CA1099371A - Control system for multi-stage reducing apparatus - Google Patents
Control system for multi-stage reducing apparatusInfo
- Publication number
- CA1099371A CA1099371A CA292,934A CA292934A CA1099371A CA 1099371 A CA1099371 A CA 1099371A CA 292934 A CA292934 A CA 292934A CA 1099371 A CA1099371 A CA 1099371A
- Authority
- CA
- Canada
- Prior art keywords
- stage
- speed
- reducing
- speed control
- signal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES, PROFILES OR LIKE SEMI-MANUFACTURED PRODUCTS OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C1/00—Manufacture of metal sheets, wire, rods, tubes or like semi-manufactured products by drawing
- B21C1/02—Drawing metal wire or like flexible metallic material by drawing machines or apparatus in which the drawing action is effected by drums
- B21C1/12—Regulating or controlling speed of drawing drums, e.g. to influence tension; Drives; Stop or relief mechanisms
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P5/00—Arrangements specially adapted for regulating or controlling the speed or torque of two or more electric motors
- H02P5/46—Arrangements specially adapted for regulating or controlling the speed or torque of two or more electric motors for speed regulation of two or more dynamo-electric motors in relation to one another
- H02P5/50—Arrangements specially adapted for regulating or controlling the speed or torque of two or more electric motors for speed regulation of two or more dynamo-electric motors in relation to one another by comparing electrical values representing the speeds
- H02P5/51—Direct ratio control
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Power Engineering (AREA)
- Metal Extraction Processes (AREA)
- Control Of Metal Rolling (AREA)
- Control Of Velocity Or Acceleration (AREA)
- Metal Rolling (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention relates to a control system for a multi-stage reducing apparatus through which elongate material is advanced and reduced in cross section. The invention is particularly suitable for use in connection with apparatus, e.g., metal strip rolling mills and wire drawing machinery, having a series of material reducing stages through which elongate material is continuously advanced and progressively reduced in cross sectional area. The apparatus includes means for generating a set of signals representing the cross sections of the material at each of the stages, means for generating a speed control signal representative of the speed of the material at one stage, and control means responsive to the cross section signals and the speed control signal and operable for producing a plurality of speed reference signals for controlling the speed of the material at each stage, each such reference signal being proportional to the speed control signal and the ratio of the cross section of the material at said one stage and the cross section of the material at the respective stage. The control means is preferably embodied as a plurality of analog arithmetic units, for the plurality of stages, each responsive to the speed control signal and to the cross section signals of said one stage and the respective stage and operable for generating an output signal corresponding to the product of the speed control signal and the ratio of the cross sections of the material.
The present invention relates to a control system for a multi-stage reducing apparatus through which elongate material is advanced and reduced in cross section. The invention is particularly suitable for use in connection with apparatus, e.g., metal strip rolling mills and wire drawing machinery, having a series of material reducing stages through which elongate material is continuously advanced and progressively reduced in cross sectional area. The apparatus includes means for generating a set of signals representing the cross sections of the material at each of the stages, means for generating a speed control signal representative of the speed of the material at one stage, and control means responsive to the cross section signals and the speed control signal and operable for producing a plurality of speed reference signals for controlling the speed of the material at each stage, each such reference signal being proportional to the speed control signal and the ratio of the cross section of the material at said one stage and the cross section of the material at the respective stage. The control means is preferably embodied as a plurality of analog arithmetic units, for the plurality of stages, each responsive to the speed control signal and to the cross section signals of said one stage and the respective stage and operable for generating an output signal corresponding to the product of the speed control signal and the ratio of the cross sections of the material.
Description
~ ~ ~ $ 3~ ~
The present invention relates to a control system for a multi-stage redu~ing apparatus through which elongate material is advanced and reduced in cross section. The in-vention is particularly suitable for use in connection with apparatus, e.g., metal strip rolling mills and wire drawing machinery, having a series of material reducing stages through which elongate material is continuously advanced and progres-sivcly reduced in cross sectional area.
It is known in the prior art to reduce the cross section of elongate metal material by advancing the material througll successive stages of a multiwstage reducing apparatus.
Each stage includes a material advancing mechanism and an opening of smaller size than the cross section of the material advanced to the stage. The openings at successive stages of the apparatus are progressively smaller in size so that the cross section of the material is p~ogressively reduced as the material is advanced. When the material leaves the open~
ing of the final material redu~ing stage, it has the desired cross sectional shape and size. Multi-stage rolling mills and multi-stage wire drawing machines represent examples of this general type o~ equipment.
As a result of the reduction in cross sectional area o the material at each opening, the material experiences an elongation in passing through each opening. Consequen~ly, it is necessary for the material advancing mechanis~ at the suc-cessive stages of the reducing apparatus to operate at pro-gressively increasing speeds from the initial to the final stage~
When operation of such multi~stage reducing apparatus is initiated from rest, it is necessary for the prime movers~
~2 3~
e.g., electric drive motors, of the material advancing mech~
anisms to be operated at desired fixed relative speeds during the acceleration period to avoid possible breakage or the production o~ excessive material between the material reducing stages. The same fîxed proportional relationship of material speeds at the various stages is required in the operation at normal running speed for the same reasons Consequently, it is essential for successful operation of such multi-stage re-ducing apparatus to provide precise regulation of the speed o the material at each of the material reducing stages.
Control arrangements for multi~stage reducing appara~
tus have been previously proposed to allow an operator to pre-set the desired ratio of speeds between the material advancing mechanisms of the reducing stages. An example of one such arrangement is described in U. S. Patent 3,688~546, issued on Septem~er 5, 1972 to Jean Tranier. This patent discloses a speed control arrangement for a multi-stand reducing apparatus in which a dial or rule associated with each stand is provided with a logarithmic scale or rep~esenting the size~ i.e~, diameter, o the material at each stand. The dials are coupled together to provide equal movement of all dials simultaneously.
The logarithmic scales on the dials are p~ogressively offset relative to the dial associated with the final stage, with the progressive offset between the dials corresponding on a logarithmic scale to the base speed ratios between the material reducing stands. The machine operator must visually align the logarithmic scales on the dials with a series of hairlines to obtain desired size settings~ A general speed signal is applied across a parallel array o voltage dividers 3 one for each stand, with a pickup for each divider arranged to supply - .. -- : . . : ' ' ~$~
its associated drive motor with a speed control voltage dependent on the general speed control signal and the position of the pickoff along its divider. F,ach pickof-f, other than ~he final or finisher stand, is adjustable through a limited range to provide an approximately linear relationship between voltage changes and the logarithmic scale.
Because of the necessity foT an operator to manipulate the dials relative to visual hairlines, it is difficult to obtain accurate material size settings on such a control mechanism. Since all dials are coupled together for simultaneous movement, the control arrangement does not permit any flexibility in the section of relative material size settings at the various stands. In addition, because of the limited range of adjustment of the voltage dividers required to preserve the necessary linear rela-tionship between the voltage changes and logarithmic scale, -~
the range of material size settings is restricted.~
A primary objective of the present invention is to provide an improved system for controlling a multi-stage reducing apparatus to achieve more precise speed control o~
the material at the material reducing stages. Another ob-ject of the invention is to provide a control system for a multi-stage reducing apparatus which is conveniently and accurately operable over a wide range of material sizes.
It is also a purpose of the invention to achieve a multi-stage reducing apparatus in which the material speed at each of the reducing stages is accurately controlled according to the material speed at a predetermined stage and the ratio 30 of the cross sectional areas of the material at the predeter~
' ' 7~
mined stage and the particular stage.
In accordance wlth the invention in one aspect there is provided a speed control system for a multiple stage reducing apparatus having a plurality of successive material reducing stages through whlch elongate material is continuously advanced and progressively reduced in cross sectional area, comprising manually settable means settable for generating a plurality of separate reducing stage signals representing the relative cross sectional areas o~ the material at the plurality of reducing stages respectively, means for generating a speed control signal, and circuit means responsive to the plurality of separate reducing stage signals and the speed control signal and operable for producing a plurality of speed reference signals for the plurality of reducing stages respectively operable for controlling the relative speeds of the material at the respective stages, the plurality of speed reference signals being proportional to the ratios respectively of the cross sectional area of the material at one predetermined stage of the reducing apparatus to the cross sectional areas of the material at the pluralit~ of reducing stages respectively.
A preferred embodiment of the invention may be em-~died as a multi-stage wire drawing apparatus for advancing and drawing continuous wire material stock and comprising a series of material drawing stages each including a rotatable draw block ~or advancing the wire material stock, a dri~e motor for rotating the draw block to advance the wire material stock and a die having an opening for reducing the cr~ss sectional area of the wire stock.
It will be understood that the term "opening"
used herein encompasses both the spacing between rolls in a 37~
metal strip rolling mill and the bore in a die of a wire drawing machine. However, the term "opening" is not intended to limit the scope o~ the present invention to only those types of reducing machines. In addition, the preferred embodiment may include a gear train at each stage for connecting its drive motor to its respective rotatable block, and means for modifying the speed reference signals to compensate for the different gear ratios.
The present invention also contemplates a method wherein said circuit means comprises a plurality of arithmetic units for said renlaining drawing stages respectively, each responsive to the first die size signal, speed control signal and to the respective second die size signal and -operable for generating the respective speed reference signal in accordance with the product of the speed control signal and the ratio of the die size area of the die at said one predetermined drawing stage to the die size area of the die at the respective drawing state.
~., .~j ~ 37 ~
The present invention achieves a system and method of controlling the operation of a multi-stage reducing appa-ratus in which the speed of the material at each reducing stage is precisely controlled. In addition, the invention is -readily adaptable to c.ontrol a multi-stage reducing ap-paratus over a wide range of material size.
Other cbjects will be in par~ obvious and in part pointed out more in detail hereinafter.
A better unclerstanding of this inven~ion will be obtained Tom the following detailed description and the accompanying drawings of an illustrative application of the invention.
In the drawings:
FIG. 1 is a diagrammatic illustration of a multi-stage wire drawing machin,é controlled in accordance wi~h the ,,.
system and method of the present invention;
FIG. 2 is a graph illus~rati~g the power and speed characteristics of a drive motor associated with each stage of the machine;
FIG. 3 is a block diagram of a conventional control circuit used -to control the speed of the drive motor at each `
.stage of khe'machine; and FIG. 4 is a schematic diagram of a control system . ' constructed in accordance with the preseIlt invention for con~
trolling the multi-stage reducing apparatus of FIG. lo Referring to FIG. 1, a conventional multi-stage wire dra~ing apparatus includes a series of consecutive re ~, ducing stages S~, Sb,.O.S~ through which a wire 10 is con- i tinuously advanced and progressively reduced in cross section.
Although~ for purposes o illustration, only three stages are 7 "
. .
~ 37 ~
shQWn in FIG. 1, it is understood that any desired number of reducing stages can be employed with the control system of the present invention. In addition, although the invention is specifically described in the context of a wire drawing machine, it should be appreciated that the invention is also applicable to rolling mills and other similar apparatus.
The initial stage Sa includes a drawing die 20 having an opening for receiving a wire 10 for Teducing its cross sectional area. This stage also includes a rotatable draw block 22 for drawing the wire in a conventional manner through the die 20. The draw block 22 is driven by a drive motor 24 via a gear train 25. In addition, the initial stage Sa includes a suitable dancer mechanism having a dancer pulley 26, which is movable, as indicated by arrows 27, in a con-ventional manner to maintain the wire tension at a predeter-mined level and to adjust the speed of the motor 24 according-ly~ and a fixed axis îdler pulley 28 around which the wire is fed to the next stage.
The second drawing stage Sb is substantially iden-tical to the initial stage and includes a drawing die 30having an opening for receiving the wire 10 or reducing its cross sectional area3 a rotatable draw block 32 for drawing the wire~ a drive motor 34 for rotating the draw block via a gear train 35, a dancer pulley mechanism with a danceT pulley 36 and a fixed axis idler pulley 38. The final drawing stage Sf includes a drawing die 40 having an opening for recei~ing the wire to reduce its crcss sec~ional area, a rotatable draw block 42 for drawing the w~re, and a drive motor 44 for rotating the block via a gear train 45. The final stage does not require a dancer pulley.
-~ 37 ~
As shown in FIG. 13 in the drive unit of eachmaterial reducing stage, the rotatable draw block is driven by a separate drive motor, e.g., a ~C electric motor. The speed of each motor is finely controlled within, for example, 10~ by tlle danc.er pulley to maintain wire tension and to inely tune the speed relationships of the successive stages required by the reduction in cross sectional area performed by the dies. The gear trains 25, 35~ 45 which couple the drive motors 24, 34, 44 to the rotatable draw blocks 22~ 32, 42 have gear ratios which are hereinafter designated Ga~ Gb and Gf respectively.
The circuit shown in FIG. 3 represents a conventional motor control circuit for controlling a DC motor. The same circuit can be employed at the initial stage and each înter-mediate stage of the apparatus. Substantially the same cir~
cuit is employed at the final stage with the exception that the danceT pulley control is not employed. The control cir-cuit allows each drive motor to develop a combination of speed and power anywhere within the envelope (shaded area) o the graph shown in FIG. 2.
In operation, a speed reference voltage generally desîgnated Vrn ~and specifically designated for example Vrb for the second stage) is applied via a voltage divider cir~
cuit comprising a pair of resista~c~s 50 and 52 ~o a 3-phase thyristor converter circuit 54 which develops a 3-phase volt-age for the armature of the drive motor Mn~ for example the motor ~ of the second stage Sb. The voltage foT the field coil 55 of the drive motor is derived from the 3-phase output voltage o~ converter 54 via a DC-DC converter 56 having its output applied across a voltage divider comprising a pair of ..90, .. . . . . .
;37~
resist2nces 58 and 60 to a l-phase thyristor converter cir-cuit 62. A tachometer Tn, for example a tachometer Tb f the intermediate stage Sb, provides a feedback signal to the converter circuit 54 via the resistance 52.
The dancer pulley, e.g., pulley 36 (FIG.l) of the second stage Sb~ is coupled to a dancer arm 64 CFIG. 3) which moves along ~ potentiometer 66 and applies a variable voltage via a coupling resistance 68 to the junction of resistances~0 and 52 in response to movement o-f the dancer pulley. It is understood that similar arrangements are included in the motor control circuits of the other stages, with the excep~
tion o the final stage which does ~ot require a dancer pulley speed trim control.
The control circuit of FIG~ 3 provides that the speed of each stage drive motor is directly proportional to the cor-responding stage speed reference voltage Vrn when the respec-tive dancer arm 64 is located at the mîd-point of its travel along the potentiometer 66. The reference voltage Vrn is es-tablished as hereinafter described and whereby for example the reference voltage Vrb of the second stage Sb provides a speed of the respective stage drive motor Mb which is approxi-mately correct for that stage. The dancer arm provides a relatively limited, for example up to a ~ 10% speed correction compensation for die inaccuracy and wear and fluctuation in stock hardness, etc. for main~aining the correct wire speed ratios between successive stages.
In the preferred embodiment of the invention dis~
closed herein~ the speed reference voltage Vrn employed for the drive motor of each material reducing stage is genera~ed by the control system so that the reference voltage Vrn of - 10~
-~ly stage Sn is proportional to ~a) the reference voltage VrE
of the final stage S~ (b) the ratio of the square of the ~iameter of the die opening DI f the final stage S~ to the square o the diameter of the die opening Dn of the particular stage, (c) the ratio of the gear ratio Gn of the particular stage to the gear ratio Gf o-f the final s~age, (d) the ratio of the reference voltage Vrn/motor RPM conversion ratio K~
of the particular stage Sn to the reference voltage Vr~/motor RPM conversion ratio Kf of the inal stage Sf, and (e) the ratio of the block d.iameter BDf of the final stage to the block diameter BDn of the particular stage Sn, i.e., Vrn Vrf _ - Kn BDf D 2 ~f Kf BDn That relationship is derived from an equation based on the fact ~hat ~he volumetric flow of material through the die at each stage remains constant, i.e., VEL = VEL . D~fZ (1) .
where VELn is the peripheral velocity o~ the draw block at stage Sn and VF~LE is the peripheral velocity of the draw block ~It the final stage S. The peripheral speed of the draw block at stage Sn is determined in accordance w-ith the formula:
VELn = BNn ~ BDn (2) where BNn is the RPM of the draw block of stage Sn.
The draw block speed BNn at stage Sn is equal to the motor speed Nn divided by the gear ratio Gn~ i.e., . . .
~ - ~
37~
Nn _ (3) Gn By definition:
K~ = Vrn Nn From equations (1) and (2~ it follows that I I BDn Vrn n Gn Kn V ~I BDn = V 11 . BD Df2 Tn ----- rf ' ----~~--~--- - 2 Gn . Kn Gf . K~ Dn or V = V Df2 Gn Kn ~D
rn rf Dn Gf Kf BDn (5) In the preferred embodiment of this invention, a signal V is supplied, such that c V = V . Gf.Kf Tf C --BDf Therefore:
V = V ~ BDf G~.K
and using thîs signal we can res~ate equation (5) as V = IV . BDf ~ Df2 G .I~
rn rf . _ ~
Gf.K~ Dn B~n : Therefore:
.
~12-, ;37~
V - V Df Gn.Kn Tn c Dn BDn From this analysis, it will be seen that in order to get the desired relationship between wire sp~eds at the various stages of the ~nachine, it is necessary or the motor speed of the stage Sn to be related to the motor speed of the final block by the ratio Df , i.e., to ~he ra~io of the cross sectional areas of the Dn material at the final stage Sf and the nth stage S . If the gear ratios Gn and G or block diameters BDn and BDf are no~ the same, it is also necessary to factor in the gear ratios and block diameter atios to obtain the desired motor speed relationship.
Referring to FIG. 4 9 an electronic control circuit is provided for controlling the drive motors of the material reducing stages to achieve the desired relationship between the motor speeds as described in the above analysis. For purposes of illustration, the specific control system shown is adapted for use with a five stage wire drawing machin,e having five successiv0 wire drawing stages designated Sl, S2~ S3, S and S5. Stage S5 represents the final stage of the apparatus. Although the specific control circuit utilizes analog volta~e signals having voltage magnitudes which cor~
respond to motor speeds~ cross sectional areas or ratios, it is contemplated that the same control function could be achieved by a circuit which operates on digital signals.
In accordance with the invention, the control sys-tem includés means for generating analog voltage signals representing the cross sections of the material at the suc~
cessive stages. Preferably, the control circuit of FIG. 4 incorporates a suitable manually adjus~able thumb swi-tch ~13-3~
voltage di~ider 70 for each stage and which has for example three manually settable decades 71-73 of increasing order respectively which permit the machine opera~or to establish a three place setting, to three decimal places, of the dia-meter of the die opening of the r~sp~ctive stage Thus, the thumb switch 70 provides foT establishing a digital setting within a wide range of diameter se~tings for producing an output signal having a voltage directly proportional to the diameter o the respective stage die opening. The thumb switch output voltage signal is applied via a coupling re-sistance 74 to an amplifier 75 with feedback resistance 76.
The amplifier provides an output voltage s:ignal Dn directly proportional to the thumb wheel setting and therefore the diameter of the respec~ive stage die opening. Feedback re-sistance 76 is provided to eliminate the effect of any in-ternal voltage o~ characteristic changes on the ~mplifier operation. Output signal Dn~ which is directly proportional to the diameter o the die opening, represents a cross sec~
tion dimension of the material at the ~espective stage Sn.
Thus, the control system includes five thumb switch voltage dividers 70, which are preferably substantially iden-tical, for generating a set of wire or die opening cross sec-tion signals representing the diameters of the drawing die openings a~ the i~e stages Sl-S5. As indicated~ the manually adjustable thumb switch 70 of each stage is set to correspond to the diameter o the die opening of the respective stage.
Each thumb switch is connected to a common input line 12~
having a fixed line voltage, shown to be ~10 volts, estab-lished by a suitable voltage regulator 125.
The speed control system comprises a ramp funçtion 3~
g~nerator 122 that is supplied with a desired voltage under ~he control of a speed cvntrol switch 12~ that is used to establish the speed of the multiple stage drawing apparatus and in the shown embodiment the speed of the final stage motor M5. Also, a run switch 126 is provided which functions as an on-off contr~l switch. The ramp function genera~or 122 is employed in a conventional manner for controlling the multiostage reducing apparatus ~o that it gradually accelerates to the speed established by the speed control switch 124~
The control system includes means for genera~ing speed reference voltage signals Bl-E5 representati~e of the speeds of the material at tha plurality of successive stages Sl-S5. The output voltage Dn of a~plifier 75 that represents the cross section of the material at stage Sn is applied via a fixed function analog arithmetic unit or compu-ting unit 150 and a potentiometer 152 to the non~inverting input of an operational amplifier 154. The purpose o~ potentio-meter 152 is to modify ~he output signal E of the computing unit 150 in accordance with the gear ratio Gn of the gear train at the respective stage Sn and also the ratios (if other than unity) of the conv~rsion ratio Kn and block dia-meter BDn of the Tespective stage Sn to that of the inal stage S. A feedback loop including a grounded resistance 156 and a variable resistance 158 is provided at each stage between the output of amplifier 154 and its i~verting input to allow the gain of the amplifier to be adjusted. The out-put voltage provided by ampli-fieT 154 is employed as a speed control o~:reference signal Vrn which is applied to the motor control circuit for the respective stage Sn. Thus, the final 37~
stage speed re-ference signal V 5 is proportional to the motor speed and therefore also the wire speed at the final stage.
The analog arithmetic. unit 150 provides for com-pu~îng En in accordance with the formula E = V Df2 n c and the amplifier-resistor networ~7 152, 154, 156 and 158 provides for computing V in accordance wi~h the ~ormula Vrn = En . n' n BDn to provide the proper signal to the motor control circuit.
More particularly, each stage arithmeti.c or com~
puting unit 150 provides control means which is responsive to the voltage analog signal Dn representative of the cross section of the material at that stage a the voltage analog si~nal Df representative of the cross section of the material at the last stage S~,,and the speed control signal V from the ramp ~unction generator 122, and is operable for producing a speed reference signal En - Df2 . Vc or co~trolling the ~0 speed of the material at the renpective stage. Since it will be seen that the speed reference signal E5 for the final stage S5 will equal V , the speed reference signal En; of each prior stage is proportional to the speed si~nal Vc and ~o the ratio of the cross sectional area of the wire at the final stage to the cross sectional a.rea of th0 material at :
the particular stage. :' -16~
.. .. . . . . .
.
~ 37 ~
Preferably, as shown~ there is a separate computing unit 150 for each stage, responsive to the respective stage dimension signal D 3 the speed control signal Vc, and to the final stage dimension signal Df, for generating an out-put speed signal E corresponding to the product of $he speed control signal V and the respective ra~io of the cross sec-tional areas.
Each compu~ing unit 150 may for example be a model 4302 multi-function converter manufactured by Burr~Brown of Tu`¢Son, Arizona, and appropriately hard-wired to perform the desired computation function described. ~ach such converter has a ~rZ~ inpilt connected to receive the D5 dimension output signal from the final stage amplifier 75 via a common input line 170 and a "Y" input connected via a common input line 172 to receive the Y speed control signal from the ramp function generator 122. An "X" input of the converter 150 is connected to receive a dimension output signal Dn from the respective stage amplifier 75. Each computation unit 150 is hard~wired to produce an output voltage signal Eo in accordance with the formula E = ~ , Vz2 Y ~
where V , V and V are the respective voltages applied to the "X~', "Y" and "Z" inputs of the converter 150. Thus, the output signal E~ produced by the fourth stage compu~ation unit 150 has a voltage substantially equal to ~c ~` D52.
Similarly, the output signal E3 produced by the 4 third stage computation unit 150 is equal to Vc 5 ; the output signal E2 produced by the second stage computation unit 150 -17~
7~L
is equal to Vc Sz; and the ou~put signal E5 produced by the final stage computation unit lS0 is equal to Vc 2 or Vc.
Accordingly, in the specific embodiment of the con-trol system which is shown, the final stage computation unit 150 is ulmecessary and ~he Vc output signal from the ramp function generator 122 can be employed as the input slgnal to the final stage resistor 152. However, the final stage computation unit 150 is preferably provided as shown so that all o-f the individual stage systems are substantially iden-tical and to thereby simplify the installation, repair and main~enance of the control system in the field.
If desired, the dancer trim circuits can be replaced by a different type of automatic speed trim system or by suitable manually operated speed trim circuits connected like the dancer trim circuits as shown in FIG. 3 or in the alter-native connected for modifying the dimension vol~age output signals Dl-D5 from the thumb wheel voltage dividers 70. OT
each thumb wheel voltage divider may be used for manually trimming the speed of the respective draw block.
If desired, each set of thumb wheels 71~73 may be preset to the cross sectional area o the material at the respective material reducing stage9 in which event, a multi~
plication/division type of arithmetic unit would be provided in place of the described aTithmetic unit 150 in order to p~ovide an arithmetic unit output signal having a voltage ~n = Vc f2 as described.
The control system and method of the present inven~
tion provide for extremely accurate control oE the material speed at each of the successive stages of the multi-stage re~
ducing apparatus. In addition, the invention is readily ~18-7~
adaptable for use with multi-stage reducing apparatus over a wide range of cross sections of material to be reduced.
As will be apparent to persons skilled in the art, various modifications, adaptations and variations of the foregoing speci-fic disclosure can be made without departing from the teachings of this invention.
- 1 9 ~
,
The present invention relates to a control system for a multi-stage redu~ing apparatus through which elongate material is advanced and reduced in cross section. The in-vention is particularly suitable for use in connection with apparatus, e.g., metal strip rolling mills and wire drawing machinery, having a series of material reducing stages through which elongate material is continuously advanced and progres-sivcly reduced in cross sectional area.
It is known in the prior art to reduce the cross section of elongate metal material by advancing the material througll successive stages of a multiwstage reducing apparatus.
Each stage includes a material advancing mechanism and an opening of smaller size than the cross section of the material advanced to the stage. The openings at successive stages of the apparatus are progressively smaller in size so that the cross section of the material is p~ogressively reduced as the material is advanced. When the material leaves the open~
ing of the final material redu~ing stage, it has the desired cross sectional shape and size. Multi-stage rolling mills and multi-stage wire drawing machines represent examples of this general type o~ equipment.
As a result of the reduction in cross sectional area o the material at each opening, the material experiences an elongation in passing through each opening. Consequen~ly, it is necessary for the material advancing mechanis~ at the suc-cessive stages of the reducing apparatus to operate at pro-gressively increasing speeds from the initial to the final stage~
When operation of such multi~stage reducing apparatus is initiated from rest, it is necessary for the prime movers~
~2 3~
e.g., electric drive motors, of the material advancing mech~
anisms to be operated at desired fixed relative speeds during the acceleration period to avoid possible breakage or the production o~ excessive material between the material reducing stages. The same fîxed proportional relationship of material speeds at the various stages is required in the operation at normal running speed for the same reasons Consequently, it is essential for successful operation of such multi-stage re-ducing apparatus to provide precise regulation of the speed o the material at each of the material reducing stages.
Control arrangements for multi~stage reducing appara~
tus have been previously proposed to allow an operator to pre-set the desired ratio of speeds between the material advancing mechanisms of the reducing stages. An example of one such arrangement is described in U. S. Patent 3,688~546, issued on Septem~er 5, 1972 to Jean Tranier. This patent discloses a speed control arrangement for a multi-stand reducing apparatus in which a dial or rule associated with each stand is provided with a logarithmic scale or rep~esenting the size~ i.e~, diameter, o the material at each stand. The dials are coupled together to provide equal movement of all dials simultaneously.
The logarithmic scales on the dials are p~ogressively offset relative to the dial associated with the final stage, with the progressive offset between the dials corresponding on a logarithmic scale to the base speed ratios between the material reducing stands. The machine operator must visually align the logarithmic scales on the dials with a series of hairlines to obtain desired size settings~ A general speed signal is applied across a parallel array o voltage dividers 3 one for each stand, with a pickup for each divider arranged to supply - .. -- : . . : ' ' ~$~
its associated drive motor with a speed control voltage dependent on the general speed control signal and the position of the pickoff along its divider. F,ach pickof-f, other than ~he final or finisher stand, is adjustable through a limited range to provide an approximately linear relationship between voltage changes and the logarithmic scale.
Because of the necessity foT an operator to manipulate the dials relative to visual hairlines, it is difficult to obtain accurate material size settings on such a control mechanism. Since all dials are coupled together for simultaneous movement, the control arrangement does not permit any flexibility in the section of relative material size settings at the various stands. In addition, because of the limited range of adjustment of the voltage dividers required to preserve the necessary linear rela-tionship between the voltage changes and logarithmic scale, -~
the range of material size settings is restricted.~
A primary objective of the present invention is to provide an improved system for controlling a multi-stage reducing apparatus to achieve more precise speed control o~
the material at the material reducing stages. Another ob-ject of the invention is to provide a control system for a multi-stage reducing apparatus which is conveniently and accurately operable over a wide range of material sizes.
It is also a purpose of the invention to achieve a multi-stage reducing apparatus in which the material speed at each of the reducing stages is accurately controlled according to the material speed at a predetermined stage and the ratio 30 of the cross sectional areas of the material at the predeter~
' ' 7~
mined stage and the particular stage.
In accordance wlth the invention in one aspect there is provided a speed control system for a multiple stage reducing apparatus having a plurality of successive material reducing stages through whlch elongate material is continuously advanced and progressively reduced in cross sectional area, comprising manually settable means settable for generating a plurality of separate reducing stage signals representing the relative cross sectional areas o~ the material at the plurality of reducing stages respectively, means for generating a speed control signal, and circuit means responsive to the plurality of separate reducing stage signals and the speed control signal and operable for producing a plurality of speed reference signals for the plurality of reducing stages respectively operable for controlling the relative speeds of the material at the respective stages, the plurality of speed reference signals being proportional to the ratios respectively of the cross sectional area of the material at one predetermined stage of the reducing apparatus to the cross sectional areas of the material at the pluralit~ of reducing stages respectively.
A preferred embodiment of the invention may be em-~died as a multi-stage wire drawing apparatus for advancing and drawing continuous wire material stock and comprising a series of material drawing stages each including a rotatable draw block ~or advancing the wire material stock, a dri~e motor for rotating the draw block to advance the wire material stock and a die having an opening for reducing the cr~ss sectional area of the wire stock.
It will be understood that the term "opening"
used herein encompasses both the spacing between rolls in a 37~
metal strip rolling mill and the bore in a die of a wire drawing machine. However, the term "opening" is not intended to limit the scope o~ the present invention to only those types of reducing machines. In addition, the preferred embodiment may include a gear train at each stage for connecting its drive motor to its respective rotatable block, and means for modifying the speed reference signals to compensate for the different gear ratios.
The present invention also contemplates a method wherein said circuit means comprises a plurality of arithmetic units for said renlaining drawing stages respectively, each responsive to the first die size signal, speed control signal and to the respective second die size signal and -operable for generating the respective speed reference signal in accordance with the product of the speed control signal and the ratio of the die size area of the die at said one predetermined drawing stage to the die size area of the die at the respective drawing state.
~., .~j ~ 37 ~
The present invention achieves a system and method of controlling the operation of a multi-stage reducing appa-ratus in which the speed of the material at each reducing stage is precisely controlled. In addition, the invention is -readily adaptable to c.ontrol a multi-stage reducing ap-paratus over a wide range of material size.
Other cbjects will be in par~ obvious and in part pointed out more in detail hereinafter.
A better unclerstanding of this inven~ion will be obtained Tom the following detailed description and the accompanying drawings of an illustrative application of the invention.
In the drawings:
FIG. 1 is a diagrammatic illustration of a multi-stage wire drawing machin,é controlled in accordance wi~h the ,,.
system and method of the present invention;
FIG. 2 is a graph illus~rati~g the power and speed characteristics of a drive motor associated with each stage of the machine;
FIG. 3 is a block diagram of a conventional control circuit used -to control the speed of the drive motor at each `
.stage of khe'machine; and FIG. 4 is a schematic diagram of a control system . ' constructed in accordance with the preseIlt invention for con~
trolling the multi-stage reducing apparatus of FIG. lo Referring to FIG. 1, a conventional multi-stage wire dra~ing apparatus includes a series of consecutive re ~, ducing stages S~, Sb,.O.S~ through which a wire 10 is con- i tinuously advanced and progressively reduced in cross section.
Although~ for purposes o illustration, only three stages are 7 "
. .
~ 37 ~
shQWn in FIG. 1, it is understood that any desired number of reducing stages can be employed with the control system of the present invention. In addition, although the invention is specifically described in the context of a wire drawing machine, it should be appreciated that the invention is also applicable to rolling mills and other similar apparatus.
The initial stage Sa includes a drawing die 20 having an opening for receiving a wire 10 for Teducing its cross sectional area. This stage also includes a rotatable draw block 22 for drawing the wire in a conventional manner through the die 20. The draw block 22 is driven by a drive motor 24 via a gear train 25. In addition, the initial stage Sa includes a suitable dancer mechanism having a dancer pulley 26, which is movable, as indicated by arrows 27, in a con-ventional manner to maintain the wire tension at a predeter-mined level and to adjust the speed of the motor 24 according-ly~ and a fixed axis îdler pulley 28 around which the wire is fed to the next stage.
The second drawing stage Sb is substantially iden-tical to the initial stage and includes a drawing die 30having an opening for receiving the wire 10 or reducing its cross sectional area3 a rotatable draw block 32 for drawing the wire~ a drive motor 34 for rotating the draw block via a gear train 35, a dancer pulley mechanism with a danceT pulley 36 and a fixed axis idler pulley 38. The final drawing stage Sf includes a drawing die 40 having an opening for recei~ing the wire to reduce its crcss sec~ional area, a rotatable draw block 42 for drawing the w~re, and a drive motor 44 for rotating the block via a gear train 45. The final stage does not require a dancer pulley.
-~ 37 ~
As shown in FIG. 13 in the drive unit of eachmaterial reducing stage, the rotatable draw block is driven by a separate drive motor, e.g., a ~C electric motor. The speed of each motor is finely controlled within, for example, 10~ by tlle danc.er pulley to maintain wire tension and to inely tune the speed relationships of the successive stages required by the reduction in cross sectional area performed by the dies. The gear trains 25, 35~ 45 which couple the drive motors 24, 34, 44 to the rotatable draw blocks 22~ 32, 42 have gear ratios which are hereinafter designated Ga~ Gb and Gf respectively.
The circuit shown in FIG. 3 represents a conventional motor control circuit for controlling a DC motor. The same circuit can be employed at the initial stage and each înter-mediate stage of the apparatus. Substantially the same cir~
cuit is employed at the final stage with the exception that the danceT pulley control is not employed. The control cir-cuit allows each drive motor to develop a combination of speed and power anywhere within the envelope (shaded area) o the graph shown in FIG. 2.
In operation, a speed reference voltage generally desîgnated Vrn ~and specifically designated for example Vrb for the second stage) is applied via a voltage divider cir~
cuit comprising a pair of resista~c~s 50 and 52 ~o a 3-phase thyristor converter circuit 54 which develops a 3-phase volt-age for the armature of the drive motor Mn~ for example the motor ~ of the second stage Sb. The voltage foT the field coil 55 of the drive motor is derived from the 3-phase output voltage o~ converter 54 via a DC-DC converter 56 having its output applied across a voltage divider comprising a pair of ..90, .. . . . . .
;37~
resist2nces 58 and 60 to a l-phase thyristor converter cir-cuit 62. A tachometer Tn, for example a tachometer Tb f the intermediate stage Sb, provides a feedback signal to the converter circuit 54 via the resistance 52.
The dancer pulley, e.g., pulley 36 (FIG.l) of the second stage Sb~ is coupled to a dancer arm 64 CFIG. 3) which moves along ~ potentiometer 66 and applies a variable voltage via a coupling resistance 68 to the junction of resistances~0 and 52 in response to movement o-f the dancer pulley. It is understood that similar arrangements are included in the motor control circuits of the other stages, with the excep~
tion o the final stage which does ~ot require a dancer pulley speed trim control.
The control circuit of FIG~ 3 provides that the speed of each stage drive motor is directly proportional to the cor-responding stage speed reference voltage Vrn when the respec-tive dancer arm 64 is located at the mîd-point of its travel along the potentiometer 66. The reference voltage Vrn is es-tablished as hereinafter described and whereby for example the reference voltage Vrb of the second stage Sb provides a speed of the respective stage drive motor Mb which is approxi-mately correct for that stage. The dancer arm provides a relatively limited, for example up to a ~ 10% speed correction compensation for die inaccuracy and wear and fluctuation in stock hardness, etc. for main~aining the correct wire speed ratios between successive stages.
In the preferred embodiment of the invention dis~
closed herein~ the speed reference voltage Vrn employed for the drive motor of each material reducing stage is genera~ed by the control system so that the reference voltage Vrn of - 10~
-~ly stage Sn is proportional to ~a) the reference voltage VrE
of the final stage S~ (b) the ratio of the square of the ~iameter of the die opening DI f the final stage S~ to the square o the diameter of the die opening Dn of the particular stage, (c) the ratio of the gear ratio Gn of the particular stage to the gear ratio Gf o-f the final s~age, (d) the ratio of the reference voltage Vrn/motor RPM conversion ratio K~
of the particular stage Sn to the reference voltage Vr~/motor RPM conversion ratio Kf of the inal stage Sf, and (e) the ratio of the block d.iameter BDf of the final stage to the block diameter BDn of the particular stage Sn, i.e., Vrn Vrf _ - Kn BDf D 2 ~f Kf BDn That relationship is derived from an equation based on the fact ~hat ~he volumetric flow of material through the die at each stage remains constant, i.e., VEL = VEL . D~fZ (1) .
where VELn is the peripheral velocity o~ the draw block at stage Sn and VF~LE is the peripheral velocity of the draw block ~It the final stage S. The peripheral speed of the draw block at stage Sn is determined in accordance w-ith the formula:
VELn = BNn ~ BDn (2) where BNn is the RPM of the draw block of stage Sn.
The draw block speed BNn at stage Sn is equal to the motor speed Nn divided by the gear ratio Gn~ i.e., . . .
~ - ~
37~
Nn _ (3) Gn By definition:
K~ = Vrn Nn From equations (1) and (2~ it follows that I I BDn Vrn n Gn Kn V ~I BDn = V 11 . BD Df2 Tn ----- rf ' ----~~--~--- - 2 Gn . Kn Gf . K~ Dn or V = V Df2 Gn Kn ~D
rn rf Dn Gf Kf BDn (5) In the preferred embodiment of this invention, a signal V is supplied, such that c V = V . Gf.Kf Tf C --BDf Therefore:
V = V ~ BDf G~.K
and using thîs signal we can res~ate equation (5) as V = IV . BDf ~ Df2 G .I~
rn rf . _ ~
Gf.K~ Dn B~n : Therefore:
.
~12-, ;37~
V - V Df Gn.Kn Tn c Dn BDn From this analysis, it will be seen that in order to get the desired relationship between wire sp~eds at the various stages of the ~nachine, it is necessary or the motor speed of the stage Sn to be related to the motor speed of the final block by the ratio Df , i.e., to ~he ra~io of the cross sectional areas of the Dn material at the final stage Sf and the nth stage S . If the gear ratios Gn and G or block diameters BDn and BDf are no~ the same, it is also necessary to factor in the gear ratios and block diameter atios to obtain the desired motor speed relationship.
Referring to FIG. 4 9 an electronic control circuit is provided for controlling the drive motors of the material reducing stages to achieve the desired relationship between the motor speeds as described in the above analysis. For purposes of illustration, the specific control system shown is adapted for use with a five stage wire drawing machin,e having five successiv0 wire drawing stages designated Sl, S2~ S3, S and S5. Stage S5 represents the final stage of the apparatus. Although the specific control circuit utilizes analog volta~e signals having voltage magnitudes which cor~
respond to motor speeds~ cross sectional areas or ratios, it is contemplated that the same control function could be achieved by a circuit which operates on digital signals.
In accordance with the invention, the control sys-tem includés means for generating analog voltage signals representing the cross sections of the material at the suc~
cessive stages. Preferably, the control circuit of FIG. 4 incorporates a suitable manually adjus~able thumb swi-tch ~13-3~
voltage di~ider 70 for each stage and which has for example three manually settable decades 71-73 of increasing order respectively which permit the machine opera~or to establish a three place setting, to three decimal places, of the dia-meter of the die opening of the r~sp~ctive stage Thus, the thumb switch 70 provides foT establishing a digital setting within a wide range of diameter se~tings for producing an output signal having a voltage directly proportional to the diameter o the respective stage die opening. The thumb switch output voltage signal is applied via a coupling re-sistance 74 to an amplifier 75 with feedback resistance 76.
The amplifier provides an output voltage s:ignal Dn directly proportional to the thumb wheel setting and therefore the diameter of the respec~ive stage die opening. Feedback re-sistance 76 is provided to eliminate the effect of any in-ternal voltage o~ characteristic changes on the ~mplifier operation. Output signal Dn~ which is directly proportional to the diameter o the die opening, represents a cross sec~
tion dimension of the material at the ~espective stage Sn.
Thus, the control system includes five thumb switch voltage dividers 70, which are preferably substantially iden-tical, for generating a set of wire or die opening cross sec-tion signals representing the diameters of the drawing die openings a~ the i~e stages Sl-S5. As indicated~ the manually adjustable thumb switch 70 of each stage is set to correspond to the diameter o the die opening of the respective stage.
Each thumb switch is connected to a common input line 12~
having a fixed line voltage, shown to be ~10 volts, estab-lished by a suitable voltage regulator 125.
The speed control system comprises a ramp funçtion 3~
g~nerator 122 that is supplied with a desired voltage under ~he control of a speed cvntrol switch 12~ that is used to establish the speed of the multiple stage drawing apparatus and in the shown embodiment the speed of the final stage motor M5. Also, a run switch 126 is provided which functions as an on-off contr~l switch. The ramp function genera~or 122 is employed in a conventional manner for controlling the multiostage reducing apparatus ~o that it gradually accelerates to the speed established by the speed control switch 124~
The control system includes means for genera~ing speed reference voltage signals Bl-E5 representati~e of the speeds of the material at tha plurality of successive stages Sl-S5. The output voltage Dn of a~plifier 75 that represents the cross section of the material at stage Sn is applied via a fixed function analog arithmetic unit or compu-ting unit 150 and a potentiometer 152 to the non~inverting input of an operational amplifier 154. The purpose o~ potentio-meter 152 is to modify ~he output signal E of the computing unit 150 in accordance with the gear ratio Gn of the gear train at the respective stage Sn and also the ratios (if other than unity) of the conv~rsion ratio Kn and block dia-meter BDn of the Tespective stage Sn to that of the inal stage S. A feedback loop including a grounded resistance 156 and a variable resistance 158 is provided at each stage between the output of amplifier 154 and its i~verting input to allow the gain of the amplifier to be adjusted. The out-put voltage provided by ampli-fieT 154 is employed as a speed control o~:reference signal Vrn which is applied to the motor control circuit for the respective stage Sn. Thus, the final 37~
stage speed re-ference signal V 5 is proportional to the motor speed and therefore also the wire speed at the final stage.
The analog arithmetic. unit 150 provides for com-pu~îng En in accordance with the formula E = V Df2 n c and the amplifier-resistor networ~7 152, 154, 156 and 158 provides for computing V in accordance wi~h the ~ormula Vrn = En . n' n BDn to provide the proper signal to the motor control circuit.
More particularly, each stage arithmeti.c or com~
puting unit 150 provides control means which is responsive to the voltage analog signal Dn representative of the cross section of the material at that stage a the voltage analog si~nal Df representative of the cross section of the material at the last stage S~,,and the speed control signal V from the ramp ~unction generator 122, and is operable for producing a speed reference signal En - Df2 . Vc or co~trolling the ~0 speed of the material at the renpective stage. Since it will be seen that the speed reference signal E5 for the final stage S5 will equal V , the speed reference signal En; of each prior stage is proportional to the speed si~nal Vc and ~o the ratio of the cross sectional area of the wire at the final stage to the cross sectional a.rea of th0 material at :
the particular stage. :' -16~
.. .. . . . . .
.
~ 37 ~
Preferably, as shown~ there is a separate computing unit 150 for each stage, responsive to the respective stage dimension signal D 3 the speed control signal Vc, and to the final stage dimension signal Df, for generating an out-put speed signal E corresponding to the product of $he speed control signal V and the respective ra~io of the cross sec-tional areas.
Each compu~ing unit 150 may for example be a model 4302 multi-function converter manufactured by Burr~Brown of Tu`¢Son, Arizona, and appropriately hard-wired to perform the desired computation function described. ~ach such converter has a ~rZ~ inpilt connected to receive the D5 dimension output signal from the final stage amplifier 75 via a common input line 170 and a "Y" input connected via a common input line 172 to receive the Y speed control signal from the ramp function generator 122. An "X" input of the converter 150 is connected to receive a dimension output signal Dn from the respective stage amplifier 75. Each computation unit 150 is hard~wired to produce an output voltage signal Eo in accordance with the formula E = ~ , Vz2 Y ~
where V , V and V are the respective voltages applied to the "X~', "Y" and "Z" inputs of the converter 150. Thus, the output signal E~ produced by the fourth stage compu~ation unit 150 has a voltage substantially equal to ~c ~` D52.
Similarly, the output signal E3 produced by the 4 third stage computation unit 150 is equal to Vc 5 ; the output signal E2 produced by the second stage computation unit 150 -17~
7~L
is equal to Vc Sz; and the ou~put signal E5 produced by the final stage computation unit lS0 is equal to Vc 2 or Vc.
Accordingly, in the specific embodiment of the con-trol system which is shown, the final stage computation unit 150 is ulmecessary and ~he Vc output signal from the ramp function generator 122 can be employed as the input slgnal to the final stage resistor 152. However, the final stage computation unit 150 is preferably provided as shown so that all o-f the individual stage systems are substantially iden-tical and to thereby simplify the installation, repair and main~enance of the control system in the field.
If desired, the dancer trim circuits can be replaced by a different type of automatic speed trim system or by suitable manually operated speed trim circuits connected like the dancer trim circuits as shown in FIG. 3 or in the alter-native connected for modifying the dimension vol~age output signals Dl-D5 from the thumb wheel voltage dividers 70. OT
each thumb wheel voltage divider may be used for manually trimming the speed of the respective draw block.
If desired, each set of thumb wheels 71~73 may be preset to the cross sectional area o the material at the respective material reducing stage9 in which event, a multi~
plication/division type of arithmetic unit would be provided in place of the described aTithmetic unit 150 in order to p~ovide an arithmetic unit output signal having a voltage ~n = Vc f2 as described.
The control system and method of the present inven~
tion provide for extremely accurate control oE the material speed at each of the successive stages of the multi-stage re~
ducing apparatus. In addition, the invention is readily ~18-7~
adaptable for use with multi-stage reducing apparatus over a wide range of cross sections of material to be reduced.
As will be apparent to persons skilled in the art, various modifications, adaptations and variations of the foregoing speci-fic disclosure can be made without departing from the teachings of this invention.
- 1 9 ~
,
Claims (10)
1. A speed control system for a multiple stage reducing apparatus having a plurality of successive material reducing stages through which elongate material is continu-ously advanced and progressively reduced in cross sectional area, comprising manually settable means settable for gener-ating a plurality of separate reducing stage signals repre-senting the relative cross sectional areas of the material at the plurality of reducing stages respectively, means for generating a speed control signal, and circuit means respon-sive to the plurality of separate reducing stage signals and the speed control signal and operable for producing a plural-ity of speed reference signals for the plurality of reducing stages respectively operable for controlling the relative speeds of the material at the respective stages, the plurality of speed reference signals being proportional to the ratios respectively of the cross sectional area of the material at one predetermined stage of the reducing apparatus to the cross sectional areas of the material at the plurality of reducing stages respectively.
2. The speed control system of claim 1 wherein said circuit means comprises an arithmetic unit for at least each of the reducing stages of the reducing apparatus ex-cepting said one predetermined stage, each responsive to the reducing stage signals of the corresponding reducing stage and of said one predetermined stage and to the speed control signal and operable for producing the respective speed refer-ence signal.
3. The speed control system of claim 1 wherein the speed reference signals are proportional to the respec-tive products of said speed control signal and said ratios.
4. The speed control system of claim 1 wherein said one predetermined stage is the final reducing stage of the apparatus.
5. The speed control system of claim 1 wherein the circuit means is operable for producing a said speed reference signal for said one predetermined reducing stage which is proportional to said speed control signal.
6. A multiple stage drawing apparatus for ad-vancing and progressively reducing the cross sectional area of elongated material, comprising a plurality of successive material drawing stages each having a die for reducing the cross sectional area of the elongated material, a rotatable draw block for drawing the material through the die at an exit draw speed dependent on the speed of the draw block and a variable speed drive motor for rotating the draw block;
first manually settable means settable for generating a first die size signal of the size of the die at one predetermined drawing stage of the apparatus, second manually settable means settable for generating a set of second die size signals of the sizes of the dies at the remaining drawing stages respec-tively; speed control means for generating a speed control signal; circuit means responsive to the first die size signal, each of the second die size signals and the speed control signal and operable for producing a plurality of speed refer-ence signals for said remaining stages respectively which are directly proportional to the ratios respectively of the die size area of said one predetermined stage to the die size areas of the respective drawing stages, and motor control means for controlling the speed of the drive motor at said one predetermined drawing stage in accordance with said speed control signal and at each said remaining drawing stage in accordance with the respective speed reference signal and so that the relative exit draw speeds at the successive drawing stages are substantially inversely proportional to the cross sectional areas of the drawn material at the respective drawing stages.
first manually settable means settable for generating a first die size signal of the size of the die at one predetermined drawing stage of the apparatus, second manually settable means settable for generating a set of second die size signals of the sizes of the dies at the remaining drawing stages respec-tively; speed control means for generating a speed control signal; circuit means responsive to the first die size signal, each of the second die size signals and the speed control signal and operable for producing a plurality of speed refer-ence signals for said remaining stages respectively which are directly proportional to the ratios respectively of the die size area of said one predetermined stage to the die size areas of the respective drawing stages, and motor control means for controlling the speed of the drive motor at said one predetermined drawing stage in accordance with said speed control signal and at each said remaining drawing stage in accordance with the respective speed reference signal and so that the relative exit draw speeds at the successive drawing stages are substantially inversely proportional to the cross sectional areas of the drawn material at the respective drawing stages.
7. The multiple stage drawing apparatus of claim 6 further comprising a reduction drive at each stage for connecting the drive motor to the respective draw block, at least some of the reduction drives having different reduction ratios, and wherein the motor control means comprises means for compensating for the different drive ratios.
8. The multiple stage drawing apparatus of claim 6 wherein said circuit means comprises a plurality of arith-metic units for said remaining drawing stages respectively, each responsive to the first die size signal, speed control signal and to the respective second die size signal and operable for generating the respective speed reference sig-nal in accordance with the product of the speed control sig-nal and the ratio of the die size area of the die at said one predetermined drawing stage to the die size area of the die at the respective drawing stage.
9. The multiple stage drawing apparatus of claim 6 wherein said one predetermined drawing stage is the final drawing stage of the apparatus.
10. A method of controlling a multiple stage reducing apparatus having a plurality of successive material reducing stages through which elongate material is continu-ously advanced and progressively reduced in cross section, each reducing stage having a drive unit for advancing the material at a speed determined by an applied signal, the method comprising the steps of generating a first signal in accordance with the cross section of the material at one predetermined reducing stage of the apparatus, generating a set of second signals in accordance with the cross sections of the material at the remaining reducing stages respectively, generating a speed control signal and applying it to the drive unit at said one predetermined reducing stage to control the speed of the material at said one stage, producing for each said remaining stage a speed reference signal in accordance with the first signal, the respective second signal and the speed control signal and so that the speed reference signal is proportional to the speed control signal and the ratio of the cross sectional area of the material at said one stage to the cross sectional area of the material at the respective stage, and applying each reference signal to the drive unit of the respective reducing stage to control the speed of the material thereat.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB52057/76 | 1976-12-14 | ||
| GB5205776 | 1976-12-14 | ||
| US770,261 | 1977-02-18 | ||
| US05/770,261 US4079609A (en) | 1976-12-14 | 1977-02-18 | Control system for multiple stage reducing apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1099371A true CA1099371A (en) | 1981-04-14 |
Family
ID=26266984
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA292,934A Expired CA1099371A (en) | 1976-12-14 | 1977-12-13 | Control system for multi-stage reducing apparatus |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS53105688A (en) |
| CA (1) | CA1099371A (en) |
| FR (1) | FR2374680A1 (en) |
| IT (1) | IT1117149B (en) |
| MX (1) | MX4735E (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109317526A (en) * | 2018-12-11 | 2019-02-12 | 珠海桑贝思精密科技有限公司 | Drawing devices and drawing machines |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5722772Y2 (en) * | 1979-09-17 | 1982-05-17 | ||
| JPS5653817A (en) * | 1979-10-08 | 1981-05-13 | Toshiba Corp | Multistage wire drawing method |
| DE4009732A1 (en) * | 1990-03-27 | 1991-10-02 | Herborn & Breitenbach | METHOD FOR CONTROLLING AND REGULATING THE DRIVE SPEED OF DRAWING DISCS OF A WIRE DRAWING MACHINE WORKING IN STRAIGHT EXTRACTION |
-
1977
- 1977-12-13 IT IT69779/77A patent/IT1117149B/en active
- 1977-12-13 MX MX776874U patent/MX4735E/en unknown
- 1977-12-13 CA CA292,934A patent/CA1099371A/en not_active Expired
- 1977-12-14 FR FR7737665A patent/FR2374680A1/en not_active Withdrawn
- 1977-12-14 JP JP15041977A patent/JPS53105688A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109317526A (en) * | 2018-12-11 | 2019-02-12 | 珠海桑贝思精密科技有限公司 | Drawing devices and drawing machines |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS53105688A (en) | 1978-09-13 |
| FR2374680A1 (en) | 1978-07-13 |
| MX4735E (en) | 1982-08-24 |
| IT1117149B (en) | 1986-02-10 |
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| MKEX | Expiry |