US2398500A - Circuit for tracer controlled machines - Google Patents

Description

J. J. JAEGER CIRCUIT FOR TRACER CONTROLLED HACHINES Filed Sept. 24, 1943 2 Sheets-Sheet 2 llWt-MUR JJaeyer a Patented Apr. 16, 1946 UNITED STATES PATENT- OFFlCE omcorr FOR TRACER CONTROLLED MACHINES Jacob J. Jaeger, West Hartford,- Conn., assignor to Niles-Bement-Pond Company, Hartford,

Conn., a corporation of Connecticut Application September 24, 1943, Serial No. 503,701

6 Claims. (01. 172439) This invention relates to tracer controlled electrically operated machine tools and its object is to provide improved clutch energizing circuits for the machine tool having means to prevent tie-energizing of some of the machine member moving clutches when thetracer lever is subject to vibrations sufilcient to open. and close its contacts. 1'

A further obiectof the invention is to provide a supplementary .relaywithin the control circults forthe machine member moving clutches, this relay serving to hold the magnet circuits for the longitudinal motion of the machine closed when the tracer lever vibratesv between its open and closed positions for the .in and "out motions of the tool so that the longitudinal motion will not stopuntil the .in"'or "out" tracer contact has fully opened.

Another object of importance is'that a supplementary or additional relay is provided so that it will operate out of synchronism with either of a. pair of relays controlling the circuits for the machine member moving clutches With the above and other objects in view the invention consists in the features of construction and operation set forth in the following specification and illustrated in the accompanying drawings.

In the drawings annexed hereto and forming a part of this specification, I have shown the invention embodied in an engine lathe, but itwill 1 be understood that the invention can be others wise embodied and that the drawings are not to be construed as defining or limiting the scope of the invention, the claims appended to this specification being relied upon for that purpose.

In the drawings:

Figure 1 is a front elevation of a lathe, the carriage and cross slide of which may be controlled by a tracer following a template or former mounted in fixed position on the base of the lathe. FiFigi. 2 is a plan view of the machine shown in Fig. 3 is a fragmentary cross sectional view of the machine shown in Figs. 1 and 2 showing the tracer, its mounting and the template by means of which the movements of the tool are'controlled.

Fig. 4 is a diagrammatic view of the circuits controlled by the tracer lever for effecting movements of the carriage and cross slide.

In its preferred form, the invention may include the following principal parts: first, amachlne tool such as an engine lathe shownin-the drawings having tool slides mounted one above the other for movements at right angles to each other; second; magnetic clutches for actuating each of the slides in either direction; third, a pattern or template supported in fixed position on r the :machine; fourth, atracer movable with said slides over a surface or edge of said pattern or template; fifth, relays operated by contacts on said tracer controlling circuits for said clutches; sixth, a delay or supplemental relay energized by operation of either of the first mentioned relays so that the supplemental relay operates momentarily after either ofsaid first relays operates; and seventh, acircult for one pair of machine membermoving clutches being controlled by said supplemental relay. a

In the operation of'tracercontrolled machines inwhich a toolor cutter is actuated relative to a work piece to-reproducethe shape of a template or model traversed by the tracer, extremely rapid vibrations ma beset up by the tool or cutter sufiiciently extensive to adversely affect operation of the machine to accurately reproduce the desired form. The tracer may be so rapidly vibrated that its tracer contacts controlling engagement and disengagement of its machine member moving clutches will be prevented from eifectively closing the clutch circuits. The machine will therefore fail to properly function,

The invention has been illustrated in connection with a machine of the type shown and described in the patent to Shaw 1,711,290, granted April30, 1929, and the present invention will be described in connection with controlling circuits, which are adevelopment of those shown in that patent, for controlling movements of a tool carriage and cross slide. It will be understood, however, that the invention may be embodied in other types of machine tools in which movements of the tool relative to the work are controlled by a tracer spindle traversing a pattern or template adapted to open and close opposed contacts and in which the means for traversing the tool over the work piece include rotating clutch magnets coupled, when energized as indicated in the above-referred to patent, to operate lead screws or other actuating means for the movable members of the machine.

Referring more in particular to the figures of the drawings, the lathe comprises the usual bed i having a headstock 2 at one end within which is mounted a work rotating spindle 3. A carriage 6 is provided on the bed which may be moved to the left or right by means of a suitable lead screw 1. Lead screw 1 is connected through suitable driving connections to magnetic clutches HI so carrying a tool holder I8 for a tool l9 and is" adapted to be moved directly toward or from the work. To effect movements of this cross or tool carrying slide 11 there is provided a transverse lead screw 20. The cross feed screw ZO-may be manually operated in the usual manner, and, in addition, is connected by means of bevel gears 22 to a shaft 23 adapted to be driven by either of a pair of magnetic clutches 12 provided in a suit able clutch housing 24' supported upon-the tool carriage so as to travel therewith. These clutches I2 are, as shown, driven by a motor 25 preferably mounted upon the carriage 6 for movement along the bed i. "The two clutcheslz in this housin 24 are similar to the clutches ill for longitudinally moving the carriage 6 so that when one clutch I2 is energized the tool moves in and when the other clutch I2 .is energized the tool moves out. The work being turned may be held betweencenters in the usual manner and'may be rotated at any desired speed.

The cross slide [1 is provided with a bracket or arm an the outer end of which supports an electric tracer 3|, the tracer point 32 of which is adapted to engage a pattern or template 33 corresponding in outline to the work being formed. The pattern or template 33 is mounted in fixed position and may be directly supported on a suitable bracket 34 secured t'o-the lathe bed I. The tracer 3! is caused to follow the pattern by the operation ot the respective lead screws 1 and 20, the operation of which is controlled by the tracer through the pairs of magnetic clutches l0 and I2. The cross slide and the lathe tool l9 will be moved toward or from the axis of the work during longitudinal movement of the slide 6 to the left or right and will reproduce the form or outline of the template on the workpiece. In this mechanism' the electric tracer controls the "in and out movement of the lathetool by controlling the circuits for the magnetic clutches l2 through which the transverse screw 20 is operated, and controls the longitudinal traversing of the work by controlling the circuits for the magnetic clutches ID by which the rotation of the lead screw 1 is controlled. The control is such that when one of the screws 1 or 2i] is operated the other is held stationary. This control of the magnetic clutches through the electric tracer is described in detail in connection" with the 'wirin'g diagram 'The magnetic clutches l0 for operating" the longitudinal lead screw '1 "for traversing the carriage 6 to the rightan'dto the' left are indicated respectivelyin the wiring diagram, Fig. 4, 'at' IDE and IDW and the magnetic clutches l2 for oper-' ating the transverse screw 20 to move the slide in and out are indicated respectively at IZN and !BT.' The tracer 3| is indicated diagrammatically and may be'similar to thatshown' in the U. S. patent to J. CI Shaw 1,518,114, granted December 2, 1924. The tracer and tracer point form no part of the present invention and will be referred to only briefly. The tracer sp indle 32 is adapted to actuate the contact carrying lever 39 pivotally mounted within the head of the tracer body 3| whenever its lowermost end touches the template. The lever 39 carries a contact 42 cooperating with an adjustable contact at the end of an insulated contact screw 43 in the bracket plate 46 supported on the tracer body 31. The tracer body 3| is grounded, as indicated, so that an electric circuit may be completed through the contacts 4243 and lever 39. A tension spring 48 and a compression spring 49 cooperate to move the upper end of the lever 39 outward- 1y, as shown in Fig. 4, to normally hold the in contacts 42-43 closed. Normally, therefore, the tool 13, travels in or toward the work until the tracer. lever 32 is tilted by contact with the template.

The pivotally mounted lever 39 also carries a contact 80 on the opposite side from contact 42 which is adapted to cooperate with an adjustable Contact 5| on an adjusting screw suitably insulated and .mounted on a lever 54 pivoted to the tracer body 3| but insulated completely there from. A compression spring and suitable ad justing screws are pr'ovi'dedioryieldably pressing" the lever forwardly toward the upper end of the first mentioned lever 39, but the forward or normal position of this auxiliary lever 54 is limited by an adjusting screw 59, the end of which carries a contact 50cooperating with a contact 61 on the upper end of 'the lever 54. The adjusting contact screw 59.is, as shown, insulated and is mounted in .the bracket plate 46.

In the circuit including the contact points 42 and 43 is the solenoid of a triple pole relay X the threecontactarmsfof which are indicated'at 10, ll and='l2. When the solenoid of the relay is energized the contact arms 10 and "II. will be in their closed positions as shown while the third contact arm 12 wnr be in its open position'also as shown. When the 'sole'noidz'of' the relay is deenergized the contact arms 10 and H and the contact arm 12 will be moved simultaneously to'their open and closed positions respectively, as for instance by the spring 73, The circuits controlled by these contact arms will be described later.

In the circuit including'the contact points 5! and 60 is the solenoid of a second triple pole relay Y, the contact arms of which are indicated at "M, '15 and 16. When the solenoid of the relay is energized the contact arms 14 and 15 will be in their closed positions while the third'cont'act arm 16 will be in its open position. When-the solenoid of the'relay is-deenergized theconta'ct arms 14 and 15' and the cont'act'arm Hi'will be moved simultaneously to their open andclo'sed positions respectively as shown, by the spring '11.

'The circuit 'forzthe" solenoid of relay X can be traced as "follows: from the ground through th'e tracer'b'ody'BI, lever 39, contacts 42 and 43, line 63;'solenoidoirelay X,'1in'e B4, junction point 83, line 51', and generator 68 to'ground.

The circuit for the solenoid of relay Y can be tracedasiollows: nomuie ground, through the tracer-beers|,-'1ever 3'9,' contac'ts 69 and 5|, line 85,so1er'ioid of relay line'i i lijunctionnoint 83, line Bland generator u to-ground. I I

The solenoid of a single polesupplementaiy rel'ay' R is also provided in circuit with the generator 68, this solenoid being energized when either of the contactarrns'lfl and 14 is in closed position. The circuit of this relayis as follows: from the ground, throughithe solenoid of said relay R, line 18, :junctionpointBfi; branch linecomprising line 19, contact arm1u;-nne*a'o-'aname 64 to junction point 83 or the branch line. comprising. line. 81, contact arm 14 andline 82 to-the junction point 83 and thence through line 61 and generator-68 to ground. The relay R controls contactarm 84 which is under the influence of a'spring 85 tending to move it to its closed position.

The relay X is adapted to control'the energizing of the clutch magnet I2N and thereby the inward movement of the tool l9. The relay Y is adapted to control the energizing of the clutch magnet IZT and thereby the outwardmovement of the tool [9.

The operation is as follows: Presume that the lever 39 is in the position shown in Fig. 4 closing the contacts and 43, then the solenoidof' relay X will be energized and contact arms'lll and 11 will be in closed positions as shown while contact arm 12 will be in open position as shown. The contact arm will close the circuit of'the solenoid of relay R and thus contact arm 84 of'said relay will lie in open position as shown. Contact 1| will close a circuit by which the clutch magnet [2N will be energized, said circuit being as follows: from the positive line 86, line 81, clutch magnet IZN, line 88, contact arm 1!, line 89 and junction point 99 to the negative line 9|. The tool l9 will consequently move inwardly towards the work.

When the tracer point 32 strikes the pattern. contacts 42 and 43' will be opened resulting in the deenergization of the solenoid of relay X and the consequential opening of the contact arms 19 and 1| and the closing of the contact arm 13. The opening of contact arm 10 will deenergize the solenoid of relay R resulting in the closing of contact arm 84. Ihe opening of the contact arm 1| will result in the breaking of the circuit through the magnet clutch I2N and the consequential stoppage of the inward movement of the tool 19. The closing of the contact arm 12 will result in the energizin of one or the other of the magnet clutches HIE, IOW depending upon the position of hand operated switch 92, and the consequential movement of the carriage 6 to the left or to the right. The circuit by which the magnet clutch IOE or IIJW is energized is as follows: positive line 86, line 93 or 93', magnet switch IIIE or IDW, line 94 or 94 switch 92, line 95, contacts 61 and 50, line 99, junction point 91, contact arm 15, line 98, contact arm 12, line 89, and junction point 99 to the negative line 9|. The closing of contact arm 84 which takes place consequent upon the opening of contact arm 19, momentarily after the closing of the contact arm 12 provides a holding circuit for the clutch magnet IDL or 19R making said circuit independent of either of the contact arms 12 or 16. This holding circuit extends from junction point 91 through line 99, contact arm 84 and line I09 to the junction point 99 thus short circuiting contact arms 12 and 16. The carriage moves to the left or the right until the shape of the pattern or template causes the tracer spindle 32 to move a sufficient distance either to re-close the contacts 4Z-43 if the pressure on the tracer point 32* is released or to close the contacts Ell-GI if the pressure is increased. Presume that the contacts 5i!6l are closed. The closing of these contacts will result in the energizing of the solenoid of the relay Y which controls the operation of the outward movement of the tool [9. Energization of the solenoid of the relay Y causes the closing of the contact arms 14 and 15 and the opening of the contact arm 16. The closing of the contact arm 15 results in the closing of a circuit which causes the energization of the magnetv clutch. 1211' and the: consequential outward movement of: the tool 19. The circuit energizing the magnet clutch HT is as follows: from positive line 89, line I 0|, magnet clutch I2T, line 102, contact arm 15, line I03, line I00, and junctionxpoint 90, to the negative line 9!.

The opening ofthe contact arm 16 has no immediate effect. This contact arm is in the circult including the contact arm 12 by which the magnet clutch "IE" or HiW'i energized but the energization of such magnet clutch is momentarily maintained owing to the holding circuit previously described which includes the contact arm 84' of. the relay R which is in closed position. This contact arm 84 is, however, opened almost immediately owing to the energization of the solenoid of said relay R which takes place upon the closing of the contact arm M which is closed simultaneously with the contact arm 15. Upon the opening of the contact arm 84 the circuit for the magnet clutch IGE or HlW will be broken and the traversing movement of the carriage Fl will be arrested.

The outward movement of the tool Will continue until the contacts 51', 69 are broken due to the. pressure on the tracer point 32 being clecreased.

If the contacts 42', 43' are closed after being open then the magnet clutch I'ZN will be energized through the circuit" previously described'but there will be a momentary delay in the opening of the circuit through the longitudinal magnet clutch IOE 0r IUW'due to th holding circuit controlled by the contact arm- 84 as described with refer ence to the relay Y, since the opening of the contact arm 12 consequent upon the oscillation of the solenoid of the relay Y, does not break the aforesaid holding circuit. The breaking of the holding circuit has to await the opening of the contact arm 84 consequent upon the energizing of the solenoid of the relay R due to the closing of contact arm 1| by the relay Y.

From the above it will be seen that closing tracer contacts 42, 43 or 60, 5| causes the operation of the supplemental relay R, and, as the circuit for operating thi supplemental relay includes contacts controlled by the relays X and Y, relay R is not energized until after the relay controlling the in Or out movement of the tool l9 has been energized. Supplemental relay R when energized opens one normally closed contact which opens the circuit to the IGE or IOW clutch magnet to stop longitudinal movement of the carriage 6.

A moment after the relay X or Y i energized the relay R is energized and opens the circuit through the clutch magnet IE or IQW, thus stopping the traversing movement of the carriage. As soon, however, as the relay X or Y releases, longitudinal movement of the carriage is immediately started by closure of contact 1| or 15.

If, during the closing operation of such contacts, the tracer contacts vibrate, due to action of the tool or cutter, the relay X or Y controlling the in or out" movement of the tool I!) will operate and release very rapidly as the tracer contacts open and close. In this condition none of the clutches may be energized for a sufficient length of time to develop the torque necessary to move the slides. However, since the supplemental relay R is energized through the contact on said relays X and Y it will not operate in exact synchronism with said relays. Consequently, the circuit to the HIE or IOW magnet will remain closed for a longer period of time than would be otherwise obtained and sufiicient time will be provided for thi motion to con tinue operation until the in or out contact points of the tracer are definitely closed or opened.

It will be seen that a manual selector switch 92 enables either the E or W clutch to be used for the traversing or leading movement of the carriage 6 and tool is along the lathe bed I so as to move either toward or away from the headstock.

What I claim is:

1. A tracer control for machine tools comprising in combination, a tracer, contacts opened and closed thereby, relays operated under control of said tracer contacts, clutch energizing circuits controlled by said relays, and a supplementary relay in the circuit of said first relays, said supplementary relay providing additional control of one of the clutch energizing circuits controlled by said first relays.

2. A tracer control for machine tool comprising in combination, a tracer, contacts opened and closed thereby, relays operated under control of said tracer contacts, clutch energizing circuits controlled by said relays, and a supplementary relay in the circuit for and energized when either of said first relays is energized, said supplementary relay providing additional control of one of the clutch energizing circuits controlled by said first relays.

3. A tracer control for machine tools comprising in combination, a tracer, contacts opened and closed thereby, relays operated under control of said tracer contacts, clutch energizing circuits controlled by said relays, and a supplementary relay in the circuit for said first relays, said supplementary relay when energized opening one of said clutch energizing circuits.

4. A tracer control for machine tools comprisins in combination, a tracer, contacts opened and closed thereby, relay operated under control of said tracer contacts, clutch energizing circuits controlled by said relays, and a supplementary relay in the circuit for and energized when either of said first relays is energized, said supplementary relay when energized opening one of said clutch energizing circuits.

5. A tracer control for machine tools comprising in combination, a tracer, contact opened and closed thereby, relays operated under control of said tracer contacts, clutch energizing circuits controlled by said relays, and a supplementary relay in the circuit for said first relays, said supplementary relay operating out of synchronism with said first relay and controlling one of the circuits controlled by said first relays.

6. A tracer control for machine tools comprising in combination, a tracer, contacts opened and closed thereby, relays operated under control of said tracer contacts, clutch energizing circuits controlled by said relays, and a supplementary relay in the circuit for said first relays and energized when either of said first relays is energized, said supplementary relay operating out of synchronism with said first relays and controlling one of the circuits controlled by said first relays.

JACOB J. JAEGER.

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