US2097429A - Grinding machine - Google Patents

Description

Nov. 2, 1937. H. L. BLOOD 2,097,429

GRINDING MACHINE Filed Jan. 13, 193"! 4 heet s-Sheet 1 mafia 1.. 2530a? Nov. 2, 1937. H, BL D 2,097,429

GRINQING MACHINE I 52 16/ a; 3mm ft 6. 757665.22 6065? Nov. 2, 1937. I BLQQD $097,429

I GRINDING MACHINE v Filed Jan. 13, 1937 4 Sheets-Sheet 3 "Ed 7'0 a? 1:. 755653 2, 1937 7 H. L. BLOOD 2,097,429

GRINDING MACHINE Filed Jan. 13, 1937 4 Sheets-Sheet 4 24 71. s1 Z .93 i

3 v w 776'ro&7 L. B2295;

Patented Nov. 2, 1937 UNITED STATES PATENT. OFFICE.

GRINDING MACHINE Application January '13, 1921, Serial No. 120,419

1-0 Claims.

The present invention relates to grinding machines and particularly. to a machine in which the rate of crossfeed movement between the grinding wheel and the workpiece is reduced upon engage:- ment between the wheel and the work with the crossfeed movement occurring rapidly until this engagement takes place.

In practically all types or grinding machines but more especially internal grinding machines,

the workpiece andgrindihg wheel at the begin:

ning of the grinding operation are spaced trans-r versely of the machine relative .to each other so that a transverse movement of either the wheel or the work-piece is necessary to bring the wheel and workpiece .into grinding contact. Until the wheel and workpiece are in engagement no grinding occurs and the relative movement transversely of the machine must accordingly take place at a rapid rate in order to reduce the inoperative'time of each grinding operation. One of the principal objects of the presentginvention is to provide for'a reduction in the rate of cross feed movement immediately upon engagement between the grinding wheel and the'workplece with this reduction occurring independently of the unfinished size of the workpiece.

In a copending application filed by Schmidt and Blood, Serial No. 68,291, filed March 11, 1936, is disclosed a structure by which the rate of crossfeed movement may be reduced upon engagement between the wheel and the workpiece and this structure incorporates an electrical circuit by which the grinding instrumentalitie's are controlled. This arrangement is entirely satisfactory thegrinding operation uponengagement between in operation, but it is desirable at times, and in certain types of machines, to avoid the electrical circuits and connections. One of theobje'cts of the present invention is to provide a mechanically actuated structure" for reducing the rate of crossfeed movement or ior procuring other changes in the wheel and the workpiece.-

The present inventioneccordingly incorporates an alternative mechanism; for: accomplishing the same, or a similar result, as inthe Schmidt and Blood application' In the present invention the change in the grinding operation which is procured by engagement between the wheel and the workpiece is efiected by a slight movement of the wheelhead relative'to the base of the machine, and mechanical elements provide a con nection between the wheelhead and the mecha; nism controlled thereby.

Other and further objects and advantages otthe invention will moreiully appear from the fol- Fig. 3 is a vertical section substantially along the line 1-4 of Fig. 2.

Fig. 4 is a vertical section substantially along the line 4-4 of Fig. 3, with parts broken away to show the crossieed mechanism more clearly.

Fig. 5 is an end elevation, with parts broken awaypotthe wheelhead and associated mechanism.

Fig. 6 is a fluid pressure diagram.

Fig. 7 is a view corresponding-to Fig. 5 showing a m d fication.

Like reference characters refer to like parts in the diilere'nt figures. v

' Referring first to Fig. l, the'machine has the usualreciprocatory table I provided in an interrial grinding machine; either the grinding wheel or the workpiece to beground is carried on said table, the feciprocationsof the latter operating in either case to produce a relative translatory movement between thewheel and the workpiece. In the'constructlon shown. the table'supports and carriesa workh'ead l and the-wheelhead s is mounted on abridge 4 which spans the guideways 5, Fig. 3, provided by the base 6 of the ma-' chine for the movements of the table I. The grinding wheel 'l'is, carried on a spindle! journalled in'the-wheelhead 3, and is suitably rotated at .a hlghrateof speed by any well known mechanism, which, in the presentinstance, consists of a-motonnot shown, in the base of the machine, connected by a belt, also not shown, to

- apulley, !.,IFlg 5-,- onthe spindle.

- speedirom a motor? it connected to the spindle II; by a belt IS. The clutch mechanism ll, of any well known construction, provides for stopping the rotation of the chuck without interfering with the operation or the motor II. The clutch mechanism is'under the control of a handle IS easlly. accesslble'to the operator of the machine.

The reciprocatlons of the table I to 'cause the desired relative traverse between the rotating grinding wheel and the work-supporting struc-" ture are imparted in any well known manner, as by the use of fluid pressure controlling and reverslng mechanism, one type oi. which is de- 55 ll v scribed in the Blood and Burns Patent No. 2,011,- 705, dated August 20, 1935. It is sufllcient to note for the purpose of the present application that reversal of the table is procured at each end of the normal working stroke by spaced reversin dogs l6 and II, which are carried by blocks l8 and I8 adjustably mounted on the front of the table i and adapted alternately to engage and move a reversing lever 28. The reversing lever is connected by suitable mechanism to a reversing valve 2|, Fig. 6. The reversing lever 26 during the grinding operation, when the grinding wheel is within the bore of the workpiece, is so located as to be engaged alternately by thereversingdogs.

Referring now to Fig. 6,'the pump 22, driven by a motor 26, directs fluid under pressure from a tank 24 through a pipe 25 to acasing 26 in which the reversing valve 2| is positioned. The casing 26 has an inlet port 21 to which the pipe 26 is connected, and also has spaced outlet ports 28 and-28 connected by pipes 86 and 8|, respectively, to the left and right hand ends of a cylinder "mounted in the base of the machine. A piston 88, slidable in the cylinder, has a piston rod 84 connected to a depending ing 85 on the table I. The reversing valve alternately directs fluid under pressure from the inlet port 21 to the outlet ports 26 and 28 and, at the same time, connects the opposite outlet port to an exhaust port 86 suitably connected to the tank.

The crossfeed movement between the workpiece and the grinding wheel is obtained by transverse movement of the wheelhead 3 on the bridge 4. Movement of the cross-slide 81, Fig. 3, on which the wheelhead is mounted, is effected by rotation of the crossfeed screw 36, which is held against endwise'movement by anti-friction bearings 86 engageable with the rearward end thereof. The crossfeed screw engages an internally threaded portion 46 of the cross-slide foreffecting the transverse movement thereof. On the forward end of the crossfeed screw 88 is mounted a gear 4| which meshes with a pinion 42 secured against turning movement on a shaft 43 iourhalled in a housing 44 for the crossfeed mechanism. Also secured to the shaft 48 in spaced relation to the gear 42 is a ratchet wheel 46 engageable by-spaced oppositely directed pawls I 46 and 41, Fig. 4, carried by an annular member 48 secured against turning movement on a sleeve 46 'journalled on the shaft 43. The sleeve 48 has an integral pinion 66 engageable by a rack 6| horizontally slidahle in the casing 44, said rack being held in engagement with the pinion byabearing 62. Therack 6| is shiftedbya fluid pressure mechanism,'hereinafter described in detail, and procures through the pawl and ratchet arrangement a rotation of the shaft 43, and accordingly a rotation of the crossfeed screw. Manual rotation of the crossfeed screw is by a hand wheel 43' on the end of the shaft ,46.

The pawl and ratchet arrangement 'is fully described in the Guild Patent No. 1,971,138, dated August 21, 1934. It is sufficient to note for the purpou of the present application that this double pawl arrangement permits, during the return of the crossfeed slide to original position; in readiness for a subsequent grinding operation, a compensation for the reduction in size of the grinding wheel as a result of wear and the dressing operation performed thereon during the preceding grinding operation. with reference again to Figs. 3 and 4, it will be noted that both of the pawls are normally held in operative engagement with the ratchet by a spring 53, so that a rotation of the annular member 48 provides a corresponding rotation of the ratchet 45. The pawl 41 is operative during the crossfeed movement, and the pawl 46 is operative during the retraction of the crossfeed movement, the latter involving a counterclockwise rotation of the member 46. The pawl 46 is rendered inoperative during a part of'the movement of the annular member 48 in the counterclockwise direction, so that the crossslide is retracted a slightly shorter distance than it is moved forward during the crossfeed movement.

To efiect this compensatory movement, the shaft 43 has journalled thereon an arm 64 having a gear segment 55 on the outer end thereof. The gear segment engages with a pinion 56 on a shaft 51 journalled in the front. wall of the housing 44- The outer end of the shaft 51 has a knurled knob 58 by which said shaft is turned for shifting the position of the arm 54. Integral with the arm 54 is a cam 58 in a position for engagementment of the member 48, the retraction of the V crossfeed movement takes place.

Referring now to Figs. 4 and 6, the rack 5i is carried on the end of a piston rod i, extending from a piston 62 slidable in a horizontally positioned cylinder 63 mounted on the front of the bridge. Fluid under pressure is directed alternately to oppositeends of the cylinder 63, for procuring a crossfeed movement and the retraction thereof. As shown in Fig. 6, fluid under pressure from-the pipe 25 passes through a pipe 64 to the inlet port 65 of a reversing valve casing 66 for a reversing valve 61 for the crossfeed mechanism. An outlet port 68 in the casing 66 is connected by a conduit 68 to the left hand end of the cylinder 63 and a port III is connected by a pipe '|l through suitable valve mechanisms, hereinafter described, to the right hand end of the cylinder. An exhaust port 12 for the reversing valve casing provides for exhaust of fluid from the cylinder and this port is suitably connected to the tank 24.

The structure above described is similar to structure already disclosed and claimed in prior patents and pending applications and is not of itself the present invention. The latter involves the attainment in connection with the above or similar grinding machine elements of the objects I and novel features above set forth. In accordance with the present invention the movement of the wheelhead by reason of engagement between the wheel and the workpiece is used to procure, by mechanical elements, a change in the grinding operation. This change, in the present instance,

is a reduction in the rate of crossfeed movement,

although it will be'apparent that other changes at their opposite ends by bolts I4 to a slide 15" secured in the cross-slide. The springs "are centrally connected by suitable bolts 16 to the wheelhead and the springs are shaped toprovide 75 for a small amount of oscillatory movement of the wheelhead on the slide 15, the wheelhead rocking about the lugs 15' in line with t e bolts 16.

Referring again to Fig. 5, the cm -slide 31 has mounted thereon, forwardly of the wheelhead, a housing 11 on which is mounted for rocking movement a lever 18. The support for this lever preferably comprises one or more flat springs 19 connected at one end to the housing 11 and at the opposite end to the lever between the ends thereof. One end of the lever 18 is connected by similar flat springs 89 to the wheelhead, and

it will be apparent that rocking movement of the wheelhead in the direction indicated by the arrow 8I will procure a counterclockwise turning movement of the lever 18. The rocking movement of the wheelhead is limited by an adjustable bolt 82 in the housing I1. The housing 11 has a recess therein to form a casing for a valve 83, the projecting end of which is engaged by the lower end of the lever 18 .for shifting of the valvein response to rocking movement of the lever.

With reference to Fig. 6, the housing or valve casing I1 has a port 84 connected to the pipe.1l and a second port 85 in the housing and axially spaced from the port 84 is also connected to the pipe H by a conduit 89. A port 81 in the housing 11 is connected by a conduit '88, in which is located a main throttle valve 89, to the right hand end of the cylinder 93. The housing 11 also has an exhaust port 99 suitably connected tothe tank 24. With the valve 83 in the position shown, which is the position of the valve at the beginning of the grinding operation, a reduced portion 9I of the valve provides a fluid connection between the ports 84 and 81 for directing fluid under pressure to the right hand end of the cylinder 63 when the valve 61 is shifted at the beginning of the grinding operation. When the grinding wheel engages the workpiece, the wheelhead 3 is rocked counterclockwise against the screw 82 and the valve 83 is thus shifted to the right, closing the port 84 and uncovering the port 85 to allow fluid valve 83 and into the right hand end of the cylinder 63 is .cut off, as above described, fluid under pressure still enters the right hand end of the cylinder 63 for continuing the crossfeed movement at a much slower rate. Referring again to Fig. 6, the pipe H is connected by a conduit 94 to a channel 95, in a block 98 in which is positioned the casing 91/of a valve 98. The block is secured to the bridge 4 and to the cylinder 93.

- The channel 95 in rsects spaced bores in said block in which are located throttle. valves 99 and I99, the former controlling the rate of-crossfeed movement during the rough grinding operation and the latter controlling the rate of crossfeed movement during the finish operation. The valve casing 91 has a port I9l communicating with the throttle valve 99, and the valve 98 has a removement continues under the,control of thevalve 99. It will be apparent that fluid under pressure enters the cylinder 63 through the rough feed valve 99 during the rapid crossfeed movement of the wheel into engagement with the workpiece, but the small amount of fluid passing through the valve 99 does not affect the functions of the valve 83.

As the grinding operation continues, the control' valve 98 is shifted to the right by a cam I95, Fig. 4, carriedby the annular member 48. This cam engages a roller I96 on a plunger I91 slidable in a cap I98 secured to the block 99 in line with the valve 98. When the valve 98 is shifted by the cam I95, the flow of fluid through the valve 99 is cut off and fluid then passes from the flne feed valve I99 through a port I99, Fig. 6, in the 'casing 91, around a reduced portion II9 of the -valve 98 and into the channel I93 so that during,

the last part of the grinding operation the cross- III being limited by a ring I I2; Fig. 4, on the cap I98.

The grinding operation may be brought to--a close by any suitable mechanism, as for example,

the mechanism fully disclosed in the Blood and Burns Patent No. 2,011,705, dated August 20, 1935. Whatever the type of size-controlling mechanism used, thegrinding wheel and workpiece are axially separated at the completion of the grinding operation by rendering inoperative the reversing dog I1. Simultaneously, the valve 61 is shifted by suitable mechanism, not shown, for directingfluid under pressure to the left hand end of the cylinder 63 for a retraction of the crossfeed movement. At this timethe fluid in the right hand end of the cylinder 63 exhausts through pipe 88 and the port 84 into the pipe 1I. This is possible since, immediately upon shifting of the valve 61, the fluid under pressure at the left hand end of the valve 83 is allowed to exhaust through either port 86 or 99, and the valve 83 is returned to the original position of Figs. 5 and 6 by reason of the resilient mounting of the wheelhead.

The operation of the machine so far as it is applicable to the present invention will be briefly summarized. .With the machine in the position of Fig. 1, and with a workpiece a positioned in n the chuck I9, the handle I5 is manually shifted to cause rotation of the workpiece. Movement of the table to the right to' bring the workpiece and grinding wheel into operative position, is then procured by movement of the lever II3, Fig. 1,, which is suitably connected to the table revers- As the table reaches operative ing valve 2|. grinding position, the valve 61. is shifted by any suitable mechanism, but preferably in response to the table movement, to direct fluid under .pressure into the right hand end of the cylinder 93 for the crossfeed movement.

At the beginning of the crossfeed movement, the valves 93 and 98 are in the position shown and the rate of crossfeed movement is under the control of the main throttle valve 89, for a lateral orcrossfeed movement of the grinding wheel on the wheelhead mounted for actuation by the movement of the wheelhead on the cross-slide,

thereby shifting the valve 83 to the right for locking the wheelhead against oscillatory move ment by directing fiuid under pressure to the left hand end of the valve 83. The shifting of the valve 83 also procures a reduction in the rate of crossfeed movement by cutting of! the flow of fluid under pressure through said valve to the cylinder 63.

After thereduction in. the rate of crossi'eed movement by movement of the valve 83, the grinding operation continues in the usual manner until the grinding operation is brought to a close by an extended movement of the table to the left. At the end of the grinding operation. the valve 61 is shifted, as above pointed out, to provide for a retraction of the crossfeed movement which at the same time allows the valve 83 to return to its original position with a resultant return of the wheelhead to its original position in readiness for a subsequent grinding operation.

It will be understood that, although thewheelhead is shown to be the oscillatory member by which the, change in the grinding operation is procured, in certain instances the workhead may.

if desirable, be mounted for oscillation instead of the wheelhead with the structure now shown workhead.

with reference now to Fig; 7, in which is shown a modification, the wheelhead 3' has a projecting arm H4 directly connected to the projecting end of the valve 03' corresponding to the valve 83. The valve is located in a casing forming part of a housing I1 and the latter has an adjustable bolt 82 to limit the oscillatory move-' ment of the wheelhead by engagement with a projectinglug IS. on the wheelhead. The valve 'has the reduced portion 9| which provides a connection between the ports 84' and I1 and in, the housing 11', and the latter also has the port 85' and exhaust port 9|. An axial channel 1 92' corresponds to the axial channel. I! and communicates with the reduced portion 93'. The operation of this modification is similar to' that above outlined since upon engagement between thegrinding, wheel and the workpiece during the crossfeed movement the wheelhead I is rocked counterclockwise, shifting the valve 83' upwardly. This movement of the valve 03' corresponds to a movement of the valve 83 to the right. The remainder of the operation is precisely the same as above outlined.

From the foregoing it will be apparent that the invention provides a mechanism for procuring a change in the grinding operation by engagement between the grinding wheel and the workpiece. The mechanism is mechanically actuated to avoid the use of any electrical connections where they are not desirable. One change in the grinding operation may be, as above disclosed, a reduction in the rate of crossieed movement, and this is procured by a movement of the wheelhead relative to the base, resulting from engagement between the wheel and the workpiece. This movement of the wheelhead will take place independently of variations in the unfinished diameters of successive workpieces and the device is accordingly operative for the successive grinding of aplurality of workpieces which vary substantially in unfinished diameter.

I claim:- 1. In a grinding machine, a wheel supporting member having a wheel thereon, a work-supporting member having a workpiece mounted therein, means for procuring a relative movement between said members to bring the wheel and work- 4 piece into engagement, means responsive to engagement between the wheel and the workpiece for procuring a movement of one of said members relative to the supporting structure therefor, means responsive to said last movement for procuring a change in the grinding operation, and hydraulically actuated means for preventing further movement of said movable member relative to the supporting structure alter the wheel and workpiece arein engagement.

2. In a grinding machine, member having a wheel thereon, a work-supporting member having a workpiece. mounted therein, means for procuring a relative movement between said members to bring the wheel and workpiece into engagement, means responsive to. engagement between the wheel piece for procuring a movement of one of said members relative to the supporting structure therefor, means responsive to said last movement for procuring a change in the grinding operation, and hydraulically actuated means responsive to said last movement for locking the movable member against further movement relative to the supporting structure during the remainder of the grinding operation.

3. In a grinding machine, a wheel supporting member having a wheel thereon, a work-supportworkpiece into engagement, means responsive to engagement between the wheel and the workpiece for procuring a movement of one of said members relative to the supporting structure therefor, and hydraulically actuated means rendered operative by said last movement for looking the movable member against further movement relative to the supporting structure during the remainder of the grinding operation.

4. In a grinding machine,- a wheel supportin member having a wheel thereon, a work-supporting member having a workpiece mounted therein, means for procuring a relative movement between said members workpiece into engagement, means responsive to engagement between the wheel and the workpiece for procuring a movement of one. of said members relative to the supporting structure therefor, means responsive to said last movement for reducing the rate of said relative movement, and fluid pressure means for locking the movable member against further movement relative to the supporting structure during the remainder oi the grinding operation.

5. In a grinding machine, a wheel supporting member having a wheel thereo a work-supporting member having a wor piece mounted therein, hydraulically actuated'means for procuring a relative movement between said members, a valve for controlling the admission of fluid to said hydraulically actuated means, means responsive to engagement between the wheel and the workpiece for procuring a movement of one a wheel supp n and the worktobringthe wheel and,

6. In a grinding machine, a wheelsupporting member having a wheel thereon, a work-supporting member having a workpiece mounted therein, hydraulically actuated means for procuring a relative movement between said members, a valve for controlling the admission of fluid to said hydraulically actuated means, means responsive to engagement between the wheel and the workpiece for procuring a movement of one ofsaid members relative to the supporting structure therefor, means responsive to said last movement for shifting said valve directly in response to said last movement, and means directly responsive to the movement of said valve for looking the movable member against further movement relative to the supporting structure during the remainder of the grinding operation.

7. In a grinding machine, a wheel supporting member having a. wheel thereon, a work-supporting member having a workpiece mounted there in, hydraulically actuated means for procuring a relative movement between said members, means responsive to engagement between the wheel and the workpiece in the work-supporting member for procuring a movement of one of said members relative to the supporting structure therefor, and a valve movable directly in response to the movement of, said movable member relative to the supporting structure for reducing the rate of relative movement between the members and for locking the movable member against further movement relative to the supporting structure.

8.-In a grinding machine, a wheel supporting member having a wheel thereon, a work-supporting member having a workpiece mounted therein, hydraulically actuated means for procuring a relative movement between said members,

means responsive to engagement between the wheel and the workpiece in the work-supporting 40 member for procuring a movement of one of 'means controlled by said valve for locking said movable member against further movement relative to the supporting structure.

9. In a grinding machine. a wheel supporting member having a wheel thereon, a work-supporting member having a. workpiece mounted therein, a hydraulically actuated cross slide on which one of said members is mounted for a crossfeed movement between said members, means for supportingthe wheel supporting member for a slight rocking movement relative to the supporting structure when the grinding wheel engages the workpiece in the work-supporting member, valve means responsive to said rocking movement for reducing the rate of crossfeed movement, and means responsive to said valve movement for locking the wheel supporting member against further rocking movement during the remainder of the grinding operation.

10. In a grinding machine, a wheel supporting member having a wheel thereon, a work-supporting member having a workpiece mounted therein,

HAROLD L. BLOOD.

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