US2040990A - Hydraulic control mechanism - Google Patents

Description

May 19, 1936. F. s. HAAS ET AL 2,040,990

HYDRAULIC CONTROL MECHANISM Original Filed May 51, 1930 3 Sheets-Sheet l FREDERKZK S. HAAS RALPH LGOETZE 7'7 am May 19, 1936. F. s. HAAS ET AL 2,040,990

HYDRAULIC CONTROL MECHANISM Original Filed May 51, 1930 3 Sheets-Sheet 2 IIIIIJJJJIJIJIIIJI FREDERK1K S. Haas RALPH L.GoETzE\.

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May 19, 1936. F. s. HAAS ET AL 2,040,990

HYDRAULIC CONTROL MECHANI SM Original Filed May 51, 19:50 3 Shets-$heet s WWW;

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Patented May 19, 1936 PATENT OFFICE HYDRAULIC CONTROL MECHANISM Frederick s. Haas, Cincinnati, and Ralph L. Goetzel, Norwood, Ohio, assignors to Cincinnati Grinders Incorporated, a corporation of Ohio Cincinnati, Ohio,

Original application May 31, 1930, Serial Non d58,558. Divided and this application February 29, 1932, Serial No. 595,746

8 Claims.

This invention relates to improvements in grinding machines of the center type or that type in which the work is held between opposed centers for rotation about a predetermined axis and especially to improvements in the mechanism for effecting the table operation and control, being a division of a copending application which eventuated in Patent 2,012,065.

In the performance of grinding operations on work pieces held between centers, there are two methods generally employed. In the first meth- 0d the work piece is held between the centers on a. table or a supporting memberwhich is thentraversed across the face of a grinding wheel to reduce the work piece throughout its length to the same size, while in the second method the supporting centers and work piece carried thereby are held stationary as respects this traversing movement and the grinding wheel is fed directly into the work and thereby effecting the stock removal. This invention pertains particularly to the former method of grinding and especially to improved hydraulic and mechanical control means for efiecting the proper traverse of the work supporting table. It is further to be noted that the grinding wheel is fed into the work at each end of the traverse of the table either by actuating the table and work toward the wheel or actuating the wheel toward the work.

It is, therefore, one of the principal objects of the present invention to provide improved hydraulic control mechanism determining the operation of the means for actuating the table.

Other objects and advantages of the present invention should be readily apparent by reference to the following specification considered in conjunction with the accompanying drawings forming a part thereof and it is to be understood that any modifications may be made in the exact structural details there shown and described within the scope of the appended claims without departing from or exceeding the spirit of the in- Figure 5 is a sectional view taken on line 5-5 of Figure 3.

Figure 6 is a sectional view taken on line 6-6 of Figure 5'.

Figure 7 is a diagrammatic view illustrating the 5 hydraulic circuits involved in this application.

Throughout the several views of'the drawings similar reference characters are employed to denote the same or similar parts.

A machine embodying this invention may comprise a bed or support 5 having formed longitudinally thereof at its forward end ways l6 and I! for guiding during its reciprocating movement a work supporting table l8. Adjustably carried by the table at opposite ends thereof is the head stock I9 and tail stock 20 from which centers 2| and 22 respectively project. The centers 2| and 22 support a work piece 23 between them.

The head stock I9 has a motor or prime mover 24 connected through suitable transmission means enclosed within guard or casing 25 with the spindle which carries the live center 2|. To efi'ect rotation of the work piece 23 from the spindle or center 2| a dog 26 is provided being secured to the work piece and bridged over by driving pin 2'! to the said spindle. The work piece 23 is removed from between the centers 2| and 22 by retracting the said center 22 through the medium or handle 28 carried by the tail stock 20.

The table l8 and work 23 are reciprocated longitudinally of the bed while effecting a stock removal from the face of the work throughout its length by a suitable tool or grinding wheel 29 supported by the bed for this purpose. To efiect the said movement of the table l8 use is made of an hydraulic motor operated by a hydraulic circuit diagrammatically shown in Figure '1 and described in detail in applicants Patent 2,012,065.

This hydraulic medium is normally contained within a tank 13, see Figure '7, from which it is drawn through a conduit 14 by a pump 15 and discharged from the pump under pressure through a. conduit 16. The medium then passes through a conduit 11 to starting and stopping valve 18 from which it passes through port 19 formed along the exterior of valve sleeve to a port 8| for direction to the interior of the sleeve 8|! passing then through port 82 to conduit 83 for conveyance to the directional control or reverse valve 84, which directs the medium to one side or the other of hydraulic motor 30. As shown in Figure "I, the medium passes through the conduit 85 from the valve 84 to the lower side of motor 30. The spent medium discharged on the other side of the motor is directed through the conduit 86 back to the valve 84 for discharge through a conduit 81 to the sump or tank I3. The valve I8 in addition to being used as a starting and stopping valve controls the velocity or rate at whichthe table I8 is being reciprocated and is of a unique, novel construction. This valve comprises a pair of spools 18a and 18b, each having a bore therein in axial alignment to receive a spring 88 which tends to actuate the spools in opposite directions. The cannelure formed in spool 18b is utilized for connecting ports 8| and 82 formed in the sleeve 80, while the cannelure of spool 18a connects a pair of similar ports 89 and 90 formed in the said sleeve 80. The velocity or rate of movement of the table by the hydraulic motor is controlled more or less by closing off the port 89 by the shoulder 9| formed by the cannelure in the valve spool 18a.

As was noted above, the spring 88 tends to actuate the spools 18a and 18b in opposite directions away from one another and thereby holds the said spools in engagement with adjustable stops 92 and 93 respectively carried by a pivotally -mounted bell crank 94 and an arm 95. The bell crank 94 is pivotally mounted at 96 to the bracket 'or housing 40 and has a second arm 91 extending therefrom. The arm 91 of the bell crank 94 is provided with a nose 98 contacting at all times with cam face 99 formed on a flange of sleeve I journaled for rotation about a sleeve IOI. Secured to the outer end of sleeve I00 is a handle I02 having a spring pressed locking pawl co-operating with a serrated or toothed plate I03 secured to the cover of the bracket or housing 40 positioned on the forward face of the bed I within convenient reach of the operator. Adjustment of the handle I02 rotates thev sleeve I00 for adjusting the position of the cam 99 to thereby shift the spool 18a and vary the opening of port 90 to control the flow of the hydraulic mediumtherethrough. As shown in Figure 5, the port 90 is partly open to permit anormal shifting of the table so that the removal of stock from the work piece 23 takes place at the desired rate.

- While the flow of the medium through the port 90 is restricted during actual operation of the machine, the flow from the port I9 formed longitudinally of the sleeve 80 is shut oil by the spool valve 181) to stop the reciprocation of the table but an unrestricted flow is permitted during actual operation. As shown in Figure 5, ports 8| and 82 are connected permitting, as noted above an unrestricted flow of the medium therethrough. This spool 18b is shifted by the arm 95 pivoted about pivot I04 carried by the rear wall of the bracket or housing 40. The upper end of arm 95 is pivotally connected to the longitudinally shiftable link I 05 which has its opposite end pivotally connected to similar crank arm I06 pivotally carried by pivot 96. The other arm I01 of bell crank I06 is provided with a cam follower I08at all times held in engagement with the stepped cam I09 formed on a flange 0 carried by the sleeve IOI. Pivotally secured to the outer end of the sleeve IOI is the main starting and stopping lever III which may be rocked in a clockwise direction to shift the spool valve 18b and open port 8| to permit the table I8 to be actuated at a normal work feeding rate.

From the foregoing, it will be noted that handle I02 may be adjusted for positioning the valve spool 18a to determine the rate of speed at which the work supporting table will be reciprocated. It will also be noted that with starting and stopplug lever in its neutral or central position. the

flow of hydraulic medium is restricted to stop the movement of the table, while the shifting thereof to the right or in a clockwise direction will open port 8| and permit the flow of the medium therethrough determined by the setting of the valve spool 18a.

There are times when it is desired to reciprocate the work table I8 at a high or rapid traverse rate, such as when grinding bearing portions at opposite ends of a shaft, for example, to thereby materially reduce the time involved in completing a given grinding operation. To this end the arm 91 of bell crank 94 is provided with a pin 2 in the path of movement of an abutment I I3, shown in Figure 3, as an adjustable screw carried by a projection on flange I I0 of sleeve IOI. Rotation of main starting and stopping lever I I in a counterclockwise direction will cause the abutment I I3 to engage the pin H2 and actuate the bell crank 94 about its pivot 96 to shift valve spool 18a to the right, as seen in Figure 5, thereby completely uncovering port 90 and permitting an unrestricted flow of the hydraulic medium therethrough. This unrestricted flow of the medium through port 90 effects a corresponding speeding up of rotation of the power gears to correspondingly rapidly rotate the pinion shaft 48 and reciprocate the table at a rapid rate.

The longitudinally shiftable bar I05 has secured thereto a projection I I4 abutting on opposite sides with adjacent ends of springs H5 and I I6 through which depressible plungers I I1 and N8 of starting and stopping switches H9 and I20 are actuated to start and stop the head stock rotating motor 24 with which the said switches are electrically connected. From this it will be noted that actuation of the lever III to effect reciprocation of the table I8 simultaneously effects the rotation of the motor 24 and work piece 23 rotated thereby.

The directional control or reversing valve 84 is shifted at each end of the stroke of the table I8 to thereby reverse the movement of the table. To this end the valve 84 is provided with a shifter rod I 2| having a forked end and receiving between its arms a pivotally mounted lever I22.

The lever I22 is pivoted to a projection I23 depending from a casing I24 carried by the housing or bracket 40. The pin I25 projects from the lever I22 into an elongated perforation I26 formed in the upper end of one arm of bell crank I2I. This bell crank I2'I is pivoted at I28 and has its other arm I29 pivoted at I30 with one end of a link I3I. Carried by the bell crank I2'I and projecting into the perforation I26 therein and from opposite sides thereof is a pair of set screws I32 and I33 adapted to engage with the pin I 25 of lever I22. The upper end of the link I3I is pivotally connected to a crank arm I34 integral with the sleeve I35 journaled about a hollow shaft I36 supported by the bracket or housing 40. Keyed or otherwise secured to the outer end of the sleeve 35 is a reversing lever I3I extending upwardly above the bed I5 and having a projection I38 extending therefrom toward the said bed I5. The table I8 has secured to its forward edge at opposite ends thereof dogs I39 and I40 adapted to engage with the projection I38 for oscillating same about its axial center or hollow shaft I36.

At each end of the stroke of the table a slight pause is effected followed by a gradual increase in speed of movement of the table in the opposite direction. This pause is effected by an hydrau- I lie tarry valve enclosed within the casing I24.

Vertically shiftable through the casing I24 is a pair of spool valves I H and I42 having co-axial bores therein for a spring I43. The spool I is enclosed within a sleeve I44 through which portsv I 45 and I46 are formed. A'cannelure I41 formed in the spool valve I4I connects the ports I45 and I48. The spool valve I 42 is likewise enclosed in a sleeve I48 having ports I49 and I50 connected together by the passage I5I formed on the spool I42. The hydraulic medium under pressure is conveyed to the the casing I24 through a conduit I52 coupled into the casing containing the reversing valve 84 and is in direct communication with the main pressure line 11. The spool valve I42 is-provided with a reduced portion I53 having formed at the end thereof a wedge-shaped head I54 having cam faces on opposite sides thereof. These cam faces co-operate with similar cam faces formed on the end of valve shifter lever I22. A pin I55 projects from the valve spool head I54 to which is attached one end of a spring I58. The other end of said spring is secured to a pin I51 projecting from the rear face of the bell crank I21. Referrlng to Figure 6, it will be noted that the port I45 of sleeve I 44 is connected with a port I50 of sleeve I48 by a longitudinal port I58. The chamberl59 formed between valve spools MI and I42 and their containing sleeves I44 and I48 is drained through a port I formed in the valve casing I24-.

Assuming the table to be traveling to the left, as seen in Figure 1, the dog I40 upon engagement with the projection I38 would rotate lever I31 and sleeve I35 which through the crank I34 would depress link I3I. This depression of link I3I actuates the bell crank I21 in a counterclockwise direction to take up the lost motion between the pin I25 and abutment set screw I32 and then shift the valve 84 to its neutral or stop position to stop further movement of the table. At the same time through the inter-engagement of the contacting cam faces on the upper end of the bell crank and the cam faces on the head I54 the depression of link I3I forces upwardly the said head I54 and spool valve I 42 permitting the hydraulic medium flowing through the conduit I52 to fill the passage I 5|. By oscillating the bell crank I21 until the lost motion between the ends of set screws I32 and I33 is taken up and the valve 84 shifted to its neutral positionthe apex of the cam faces on the bell crank I21 is beyond thepoint of the head I54. At this time the spring I58 which was tensior ed by the raising of the head I 54 tends to actuate the said head downwardly, thereby bringing into engagement the opposite cam faces. This downward movement of the head and valve spool while freely moved upward is now restricted in its descent since it must force outwardly from the passage I5I the hydraulic medium therein. The medium is discharged through port I50 to port I58 to the upper port I45 in sleeve I44. The flow of the medium through the port I45 is restricted by the shoulder on the valve I so that the descent of the head I54 and valve spool I42 is restricted and the shifting of the valve 84 takes place only at the rate of movement of the head. This movement gradually uncovers the port through which the hydraulic medium is passing and the hydraulic motor thereby slowly picks up speed to correspondingly slowly accelerate the speed of movement of the table I8.

The adjustment of the spool valve I is obtained through cam face I6I formed on flange I62 of a sleeve I63 mounted for rotary movement about the sleeve I35. A cam follower I64 projects from the spool valve I4I into engagement with the cam IIiI being held in this engagement by a spring I43. The sleeve I63 is adjusted by a handle I65 keyed or otherwise secured thereto and locked in position by the inter-engagement of a spring pressed pawl I86 co-op- 'erating with a serrated or toothed plate I61.

From this it will be seen that the amount of tarry and rate of acceleration of the movement of the table I 8 after reversal may be adjusted to any desired limit.

From the foregoing it will be noted that there has been provided a grinding machine employ,- ing improved table actuation and control means adjustable to very fine limits for accurately controlling and actuating the table and work carried thereby.

What is claimed is:

1. In a mechanism of the class described the combination of a conduit through which an h v. draulic medium flows, a starting, stopping and velocity control valve mechanism in the conduit comprising a pair of spool valves. ports connecting the said valves, common means for actuating said spool valves to stop the flow through the ports, means for actuating one of the valves against said last mentioned means for initiating the flow of the hydraulic medium through the port, and additional means for adjusting the position of the other valve against the ac.- tuation of the common means to control the rate of flow of the medium through the port and therefore through the conduit.

2. In a mechanism of the class described the combination of a conduit through which an hydraulic medium flows, a starting, stopping and velocity control valve mechanism in the conduit comprising a pair of spool valves, ports connect-' ing the said valves, common means for actuat ing said spool valves to stop the flow through the ports, means for actuating one of the valves against said last mentioned means for initiating the flow of the hydraulic medium through the port, additional means for adjusting the position of the other valve against the actuation of the common means to control the rate of flow of the medium through the port and therefore through the conduit, and additional means for further shifting the last mentioned spool valve against said common valve shifting means to effect a rapid flow of the fluid through the ports and therea source of impelling fluid and the member to be impelled thereby, said valve mechanism including a casing, a pair of co-axially disposed valve members slideable within the casing, fluid passages in the valve members and easing providing a sinuous conduit serially embodying the valves successively, a springinterposed between said valves outwardly urging same in an axial direction, abutments terminally engaging the respective valves to individually limit their respective outward movements, a control lever, and connections between the control lever and the abutments efiective to transmit power from the lever to the abutments whereby the effective position of the individual valves may be'adjusted by movement of the lever. t

4. Means for determining the effective action of an hydraulic circuit including a pair of op.

posed valve members serially arranged in the circuit, means for yieldingly outwardly urging said valve members, independent adjustable abutments for limiting the movement of the valve members as so urged, oscillatable levers supporting said abutments, an oscillatable control lever, and power transmitting connections between the control lever and the abutment supporting levers for varying the position of the individual valves in accordance with predetermined movements of the control lever.

5. A control valve mechanism for a fluid circuit including a ported casing and a pair of independent valve members slideable within the casing for efiecting connection or blocking off of the several ports of the casing, said valves being arranged serially as respects the hydraulic flow porting of the casing, means resiliently urging the valves into port blocking positions, a first abutment adjustable to efiect' a predetermined throttle setting of one of the valves whereby the rate of flow of the hydraulic medium through the conduit is determined, a second abutment adjustable to limit the movement-of the other valve member to a fully open position, a single control lever, and power connections between the control lever and the valve member effective to shift the throttle valve to a wide open position for rapid flow or alternatively to shift the other valve to a closed position, stopping flow of the fluid when the throttle valve is in its rate determining position.

6. An hydraulic control unit including a casing having valve receiving chambers formed therein and adapted to receive rate controlling and flow controlling valves, conduits in the easing interconnectible in serial relation by the valves for determining the efiective hydraulic flow of an actuating medium through the casing, a combination valve unit contained in one of the chambers and comprising a pair of axially disposed individual valve units floating within the chamber, a compression spring interposed between said units for urging them into separated position, adjustable abutments terminally engaging the floating unit for determining the position thereof as an entirety with respect to the ports of the casing, and means for individually temporarily varying the position of an individual abutment and its associate valve member while the position of the unit as an entirety is maintained by ,the opposed abutment, substantially as and for. the purposedescribed.

7. An hydraulic control unit including 9, casing having valve receiving chambers formed therein and adapted to receive rate controlling and flow controlling valves, conduits in the easing interconnectible in serial relation by the valves for determining the effective hydraulic flow of an actuating medium through the casing, a combination valve unit contained in one of the chambers and comprising a pair of axially disposed individual valve units floating within the chamber, a compression spring interposed between said units for urging them into separated position, adjustable abutments terminally engaging the floating unit for determining the position thereof as an entirety with respect to the ports of the casing, and means for individually temporarily varying the position of an individual abutment and its associate valve member while the position of the unit as an entirety is maintained by the opposed abutment, substan-' tially as and for the purpose described, said means including a control lever having a fixed cam associated therewith for imparting the prescribed movement to one of the abutments and its associate valve and having an adjustable member for cooperation with the other abutment for variably shifting the other of said valve members for prescribed movement of the lever.

8-. Means for determining the effective action of a fluid circuit including a pair oi. opposed valve members serially arranged in the circuit, means for urging said valve members into circuit interrupting position, independent adjustable abutments for limiting the movement of the valve members as so urged, oscillatable le vers supporting said abutments, an oscillatable control lever, power transmitting connections between the control lever and the abutment supporting levers for varying the position of the individual valves in accordance with predetermined movements of the control lever, and operative connections between said power transmitting connections and the power device for the other part whereby the actuation of said second power device is determined by the oscillatable control lever in predetermined. relation to the abutment determined effect of the valves.

FREDERICK S. HAAS. RALPH L. GOETZEL.

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