US2277047A - Lapping arm - Google Patents

Description

March 24, 1942. s, INDGE 2377,04?

LAPPING ARM Filed March 17, 1941 77 swam Patented Mar. 24, 1942 UNITED STATES. PATENT OFFICE LAPPING ARM Herbert S. I'ndge, Westboro, Mass., assignor to Norton Company, Worcester, Mass.,

tion of Massachusetts Application March 17, 1941, Serial No. 383,755

8 Claims.

arm having a yieldably' mounted, reciprocably driven lapping element. Another object of the invention is to provide a lapping arm having work engaging shoes to engage the periphery of the work to be lapped which serve as a guide for the lapping arm, and to provide the arm with a yieldably mounted reciprocable lapping element.

A further object of the invention is to'provide an improved lapping arm construction which may be applied as an attachment to a-machine such as, for example, that shown in my prior U. S. Patent No. 2,166,009 dated July 11, 1939.

' Other objects will be in part obvious or in part pointed out hereinafter.

.The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, as will be exemplified in the structure to be hereinafter described, and

the scope of the application of which will be indicated in the following claims.

In the accompanying drawing in which isshown one of various possible embodiments of the mechanical features of this invention,

Fig. 1 is a fragmentary side elevation of theporting rods or slides l and H which serve as supports for a plurality of lapping arm supporting members l2. The supporting member I2 is provided with a lower half I3 by means of which the supporting member 12 may be readily clamped in adjusted position on the rods l0 and H with a lapping element to be hereinafter described in alignment with the work piece to be lapped. The lapping arm supporting member I2 serves as a support for a pivotally mounted arm I4. A pivotal connection I5 is provided between a corporathe supporting member l2 and the pivotally mounted arm M. A lapping arm I6 is pivotally connected by a pivotal connection ll to the upper end of the arm II.

The lapping arm l6 comprises a pair of parallel side plates which are spaced apart by spacing blocks I8, I9 and at one end and by a bracket 2| which is formed as an integral extension of a fluid pressure cylinder 22.

The lapping arm l6 serves as a support. for a pair of pivotally mounted members 23 and 24 which are pivotally connected by studs 25 and 26, respectively, with the lapping arm IS. The arm 23 is provided with a pair of work engaging shoes 21 and 28 which are arranged to engage the upper portion of a work piece 29. The lower arm 24 is provided with a work engaging shoe 30 which is arranged to engage the under side of the work piece 29. A pair of toggle levers 3| .and 32 are connected at their opposite ends by studs 33 and 34, respectively, with the members 23 and The inner ends of the toggle levers 3| and 32 are connected by a common stud 35 which slides within elongated slots 36 formed in the opposite side plates of the lapping arm 16.

A fluid pressure mechanism is provided to actuate the toggle levers 3| and 32 so as to swing the pivotally mounted members 23 and 24 to position the work shoes 21, 28 and 30 either in an operative position in engagement with the periphery of the work piece 29 (Fig. 1) or in an inoperative position out of engagement with the work after a lapping operation has been completed. The hydraulic cylinder 22 contains a connecting rod or link 39, the 'lower end of .which is connected with the stud 35. In the position of the parts as shown in Fig. 1, fluid under pressure is admitted from a source of supply, such as a fluid pump (not shown) within the base of the crankshaft lapping machine, through 40 and a passage 4|, into a cylinder the pipe chamber 42-, to cause the piston 36 to move upwardly toward the right to the position-shown in Fig. 1'. During this movement fluid is exhausted from a cylinder chamber 43 above the piston 36 through a pipe 44 into a reservoir (not shown).

After a lapping operation has been completed and it is desired to remove the work engaging 7 shoes 21, 28,and 30 from operative engagement with the work piece 29, the direction of movement. of fluid under pressure is reversed and fluid under pressure is passed through the pipe 24, respectively' it into the cylinder chamber 33 to cause a downward movement of the piston 36 which transmits a downward movement toward the left through. the piston rod 31, connecting; rod or link 39, to move the stud 35 downwardly within the elongated slots 36, which movement serves to break;

'the toggle levers 3| and 32 so as to rock the arms --arm supporting member i2 to serve as a guide for the'lapping arm i5 during its swinging movement.

In order to attain one object of the invention, the lapping arm I6 is provided with a reciprocable lapping element comprising a lapping stick "59 of bonded abrasive material which is arranged to be reciprocated at a comparatively rapid rate while maintained in yielding engagement with the periphery of the work piece to be lapped.

The swinging arm 23 is pro ided with an upwardly extending portion 55 which is provided with a plurality of elongated slots 52, 53, 54 and 55 which serve to support a pair of spaced parallel yieldable elements, such as relatively thin fiat springs 56 and 51. The thickness of the springs 56 and 51 has been somewhat exaggerated in the drawing in order to clarify the illustration. A pair of plates 58 and 59 are provided adjacent to the upper ends of the springs 56 and 51. A plurality of studs 60, 6|, 62 and 63 loosely fit within the elongated slots 52, 53, 54 and 55, respectively. The studs 68, 6|, 62 and 63 are provided with threaded end portions 64 and 65. The threaded portions 64 and 65 of the studs pass through holes formed in the springs 56 and 51, respectively, and pass through corresponding holes in the plates 58 and 59. Clamping nuts 66 and 61 are provided to clamp the plates 58 and 59. and the springs 56 and 51, respectively, into fixed relation with the studs 60, 6|, 62 and 63. The length bf the body of the studs 60, 6|, 62 and 63 is slightly greater than the thickness of the member 5| so that due to the elongated slots 52, 53, 54 and 55, the springs 56 and 51 are free to slide'in a substantially vertical direction. The lowerend of. the springs 56 and 51 are fastened to a block 66 by means of screws 69 and 19. The block 68 serves as a support for a lapping stick holder 1| which supports the lapping stick 50.

The fiat supporting springs 56 and 51 are relatively thin so that the lapping stick 58 may be reciprocated in operative contact with the peripheral surface of the crankpin 29 to be ground. A crank motion is provided for oscillating or reciprocating the stick 50 which may comprise a rock shaft journalled within the arm 23. The rock shaft 15 supports a downwardly extending arm 16 having a rounded and 11 which engages a hole 18 formed in the block 68 (Fig. 3). A rock arm 19 is mounted on the other end of the rock shaft 15. The upper end of the arm 19 is provided with a vertically extending groove 80 within whicha crankpin 8| rides. The crankpin 8| is eccentrically mounted on a rotatable plate 82 formed on the lower end of a rotatable shaft 83. The upper end of the shaft 83'carries a gear 84 which meshes with'a gear 85. The

gear 85 is mounted on a rotatable shaft 86. It will be readily apparent from the foregoing disclosure that rotation of the shaft 86 will be transmitted through the gear 85, the gear 84, the shaft 83, to revolve the crankpin 8| (Fig. 3) which in turn will oscillate the rock arm 19, the rock shaft 15, and the rock arm 16 to oscillate or reciprocate the lapping stick 50 so that it abrades or laps the entire length of the peripheral surface of the crankpin 29 as it is rotated.

It is desirable that the lapping stick 50 be maintained in yielding engagement with the work piece 29 so that a uniform engagement of the lapping stick 56 may be had during its entire reciprocatory stroke. In order to accomplish this desired result, a pair .of compression springs 81 and 88 are interposed between the member 5| and the block 68. Due to the fact that the springs 56 and 51 together with the entire lap element assembly are free to move in a vertical direction, the compression springs 81 and 88 will maintain the lapping stick 50- in yielding engagement with the periphery of the crnakpin 29 during the lapping operation.

A suitable driving mechanism is provided whereby a plurality of lapping arms may be utilized and a plurality of lapping sticks- 50 supported thereby may be readily driven. A pair of spaced brackets 95, only one of which has been shown in the drawing, serve as a support for a rotatable shaft 9| which is driven by means of an electric motor 92. Each of the lapping arm supporting members I2 is provided with an upwardly extending bracket 93 each of which contains a spiral gear 94 which is slidably keyed to the shaft 9| so as to facilitate a longitudinal adjustment of the lapping arm supporting member |2 in setting up the machine. Each of the spiral gears 94 meshes with a spiral gear 95 which is rotatably supported within the bracket 93 and is drivingly connected by means of a flexible driving shaft 96 with the shaft 86 on the lapping arm l6. It will be readily apparent from the foregoing disclosure that rotation of the shaft 9| by the motor 92 will be transmitted through the spiral gear 94, the spiral gear 95, the flexible driving shaft 96, to rotate the shaft 86 and thus transmit a reciprocatory movement to the lapping stick 50. Due to the flexible driving shaft 96, the lapping arm l6 may readily swing in a desired path as the crankpin 29 revolves during a lapping operation.

It will be readily apparent from the foregoing disclosure that one or more of the improved lapping arms l6 may be mounted on a crankshaft lapping machine of the type shown in my prior U. S. Patent No. 2,166,009. The driving mechanism including the shaft 9| and electric motor 94 together with thespaced supporting brackets may be readily supported on the pivotally mounted lap supporting arms 80 so that the entire lapping arm assembly may be readily rocked to an inoperative position during the loading operation.

The operation of the improved lapping arm will be readily apparent from the foregoing disclosure. Assuming the parts to have been previously adjusted, when it is desired to start a lapping operation fluid under pressure is admitted through the pipe 48, to the cylinder chamber 42, to move the piston 36 into the position illustrated in Fig. 1, which movement shifts the toggle levers 3| and 32 into the straight line position to swing the work engaging shoes 21, 29

and 30 into operative engagement with the work piece 29. At the same time, the electric motor 92 is started which, in a manner hereinabove described, serves through the flexible driving shaft 96 to impart a rapid reciprocatory movement to one or more of the lapping sticks 50, depending upon the number of lapping arms l6 mounted upon the machine.

It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a lapping machine having a movable lapping arm, a work engaging shoe on said arm to engage the periphery of a work piece so as to take up the thrust of said arm, a reciprocable lapping stick on said arm adjacent to said shoe, a fiat spring on said arm which is free to move in a direction normal to the work axis to support said lapping stick, and means to flex said spring so as to impart a reciprocatory movement to said lapping stick.

2. In a lapping machine having a pivotally mounted lapping arm, a work engaging shoe on said arm'to engage the periphery of a work piece so as to support and steady one end of said arm,

a reciprocable lapping stick on said arm adjacent to said shoe, a fiat spring on said arm which isarranged to move in a direction normal to the work axis to support said lapping stick, yieldable means to maintain said lapping stick in yielding engagement with a work piece, and means to flex said spring so as to impart a reciprocatory movement to said lapping stick.

3. In a crank lapping machine having a pivotally mounted lapping arm, a pair of toggle levers mounted on said arm, means to actuate said toggle levers, opposed work engaging shoes each one connected to one of said levers, a reciprocable lapping stick, a fiat spring connected with one of said levers yieldably to support said lapping stick in operative engagement with the periphery of a work piece, and means including an oscillatable lever to flex said spring so as to impart a reciprocatory movement to said lapping stick.

4. In a crank lapping machine having a pivotally mounted lapping arm, a pair of toggle levers mounted on said arm, means to actuate said toggle levers, opposed work engaging shoes each connected to one of said levers, a reciprocable lapping stick, a pair of spaced fiat parallel springs connected with one of said levers yieldably to support said lapping stick in operative engagement with the periphery-of a work piece,

and means including an oscillatable lever to'flexsaid spring so as to impart a reciprocatory movement to'said lapping stick.

5. In a crank lapping machine having a piv- 65 otally mounted lapping arm, a pair of toggle levers mounted on said arm, means to actuate said toggle levers, opposed work steadying shoes each connected to one of said levers so as to take up the thrust of said arm, a reciprocable lapping 6 stick, a fiat spring on one of said levers which is free to move in a direction normal 'to thework axis to support said lapping stick, yieldable means to maintain said lapping stick in yielding engagement with a work piece, and means in- 10 eluding a positively rotated crank operatively connected to flex said spring so as to impart a reciprocatory movement to said lapping stick.

' port for a rotatable work piece, a pivotally mounted lapping arm, a pair of toggle levers mounted on said arm, means to actuate said toggle levers, opposed work steadying shoes,.each shoe connected to one of said levers so as to support and steady one end of said arm relative to the work piece, a reciprocable lapping stick, a pair of flat parallel spaced springs. on one of said levers which are free to move in a direction normal to the work axis to support said lapping stick, yieldable means to maintain said lapping stick in yielding engagement with a workpiece, and means including a positively rotated crank operatively connected to flex said springs so as to impart a reciprocatory movement to said lapping stick. 2

'7. In a crank lapping machine having a support for a. rotatable work piece, a pivotally mounted lapping arm, a pair of toggle levers mounted on said arm, means to actuate said toggle levers, opposed work engaging shoes each connected to one of said levers so as to support and steady one end of said arm relative to the work piece, a reciprocable lapping stick, a pair of flat parallel spaced springs on one of said levers which are free to move in a direction normal to the work axis to support said lapping stick,

means including a crankpin operatively connected to flex said springs so as to impart a reciprocatory movement to said lapping stick, and a flexible driving shaft operatively connected to rotate said crankpin, whereby a reciprocatory motion may be transmitted to the lapping stick during the swinging movement of the lapping arm.

8. In a crank lapping machine having a pivotally mounted lapping arm, a pair of toggle levers mounted on said arm, means to actuate said toggle levers, opposed work engaging shoes each connected to one of said levers, a reciprocable lapping stick, a pair of flat parallel spaced springs which are free to move in a direction normal to the work axis to support said lapping stick, means including a crankpinoperatively connected to fiex'said springs, a motor driven shaft on said machine, and a flexible driving 0 shaft operatively connected between said motor driven shaft and said crankpin whereby rotation of said shaft serves to revolve said crankpin so as to fiex'said springs and thereby impart a reciprocatory motion to the lapping stick.

, HERBERT S. INDGE.'

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