US2260907A - Camshaft lapping machine - Google Patents

Description

v O'ct. 28, 1941. H. s. INDGE CAMSHAFT LAPPING MACHINE 2 Sheets-Sheet l Filed Jan. 12, 1940 lllllll/- HERBEH T 5. [N055 @www www Ocnzs, 1941. yH SJNDCHE y f 2,260,907

CAMSHAFT LAPPING MACHINE Filed Jan. 12,'1940 2 sheets-sheet 2 Patented Oct. 28, 1941 CAP/[SHAFT LAPPING MACHINE Herbert S. Indge, Westboro, Mass., assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application `lanuary 12, 1940, Serial No. 313,589

5 Claims.

The invention relates to abrading machines, and more particularly to a camshaft lapping machine.

One object of the invention is to provide a cam lapping machine which will more effectively lap and polish a plurality of integral cams of an automobile camshaft. A further object of the invention is to provide a cam lapping machine in which a bonded abrasive lapping element is employed. Another object of the invention is to provide a cam lapping machine in which the cam lapping arm is provided with a normally stationary lapping wheel. A further object of the invention is to provide a transversely movable lapping arm having a normally non-rotatable lapping element at one end and a follower roller actuated by a master cam adjacent to the other end of the arm.

A further object of the invention is to provide for intermittently indexing the normally non-rotatable lapping element. A further object of the invention is to provide a lapping element indexing mechanism which is actuated by and in timed relation with the transverse movement of the lapping arm. Another object of the invention is to provide automatically actuated means to withdraw the lapping arm to an inoperative position after a predetermined lapping operation has been completed. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations ofk 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 drawings in which is shown one of various possible embodiments of the mechanical features of this invention,

Fig. 1 is a cross sectional View through the improved camshaft lapping machine;

Fig. 2 is a fragmentary perspective View, on an enlarged scale, of one of the cam lappingarms and the actuating mechanism therefor;

Fig. 3 is a fragmentary side elevation, on an Y which supports a longitudinally reciprocable work supporting table II. The table ways'are provided between the base I0 and the table I I which in the preferred form are of an anti-friction'type. The base I0 is provided with a plate I3 which is fixed tothe base and is provided onits opposite edges with parallel grooves I4 and I5 which serve as inner raceways for a pair of spaced rows of anti-friction balls I6 and Il, respectively. A cage (not shown) is provided between the races to space the balls I6 and Il longitudinally as desired. The above parts form antifriction ways whereby `the table II together with a headstock I8 and a footstock (not shown) may be readily reciprocated during the lapping operation.

The arrangement of the headstock and footstock and associated parts is substantially identical with that shown in my prior Patent No. 2,166,009 dated July 11, 1939, to which reference may be had for details of disclosure not contained herein.

Lap arm support It is desirable to provide a movable support for a plurality of cam and .bearing lapping arms so that they may be simultaneously an-d rapidly moved into an operative or inoperative position, as desired. A pair of spaced supporting arms 20, only one of which has been illustrated in the drawings (Fig. 1), are mounted on a rock shaft 2| which is supported in bearings on the rear of the machine base I0. The arms 20 are provided with horizontally extending portions which are connected by two parallel spaced bars 22 and 23 which serve as slide bars or ways for supporting a plurality of lapping arms to be hereinafter described.

The lapping arm assembly supported by the arms 20 is arranged automatically to be moved to and from an operative position to facilitate loading of camshafts into the machine and removing them therefrom after a lapping operation has been completed. In order to move the entire lapping assembly to an inoperative'position, a

i fluid pressure mechanism is provided comprising a fluid pressure cylinder 24 which is pivotally connected by means of a stud 25 with the base I0 of the machine. A piston 26 is slidably mounted within the cylinder 24 and is connected to one end of a piston rod 21. The other end of the piston rod 21 is connected by a stud 2B with an arm 29 pivotally mounted on a shaft 30 supported Within the base l0. The arm 29 is provided with a stud 3l which is connected to one end of aglink 32. The other end of the link 32 is connected by a stud 33 with the adjacent ends of a pair of toggle levers 34 and 35. The toggle lever 34 is connected at its other end by means of a stud 36 with the base it and the toggle lever 35 is connected by a stud 31 with an arm 38 which is xedly mounted on the rock shaf't 2l and is arranged to rock the shaft 2i together with the arms 2l) and all of the cam and bearing lapping arms together with their supporting and actuating mechanisms either into or away from an operative position. The levers 29, 32, 34 and 35, as shown in full lines in Fig. 1, are in a position to hold the arm 38 and the arms 2li together with the entire lapping arm assembly in an operative position.

When a lapping operation has been completed, fluid under pressure is admitted to the cylinder 24 to cause the piston 2S and the piston rod 2l to move toward the right (Fig. 1) so as to shift the lever mechanism above described to rock the arm 38, the rock shaft Z l, together with the arms 2li, in a clockwise direction (Fig. 1) to move the entire lapping arm assembly to an inoperative position.

A fluid pressure system is provided to control the admission of fluid under pressure to the cylinder 2li. A pump 39 within the base It of the machine draws fluid through a pipe it from a reservoir 4l within the base lt and passes fluid under pressure through a pipe to a control valve 3. The valve 43 is of a balanced piston type having a valve stem Se which is provided at its outer end with a spool-shaped member (l5 and is connected by means of a pair of diasnetrcally opposed studs or pins l mounted on a yoked end of a control lever lll. The control lever il is pivotally supported on a stud 48 which is carried by a bracket le iixedly supported on the front of the base l@ of the machine. A plurality of valve pistons 52, 5S and Ell lare formed integral with the valve stem d. Fluid under pressure passing through the pipe 42 enters a valve chamber 55 located between the valve pistons 53 and 54 and passes out through a pipe 56 into a cylinder chamber 5l to cause the piston E@ to move toward the left (Fig. 1) to shift the lapping `arm support 20 in a lcounterclockwise direction (Fig. 1) to position the cam and bearing lapping arm in an operative position.

During the admission of fluid under pressure to the cylinder chamber El, uid is exhausted from a cylinder chamber 58 at the other end of the cylinder 24, through a pipe 59, a valve chamber 6l) located between the valve pistons 52 and 53, and out through a pipe El which exhausts into the reservoir 4l. A fluid pressure relief valve E2 is connected by a pipe 53 with the pipe A2 and serves to by-pass any excess fluid under pressure if the pressure within the pipe line 42 for any reason increases over the desired and predetermined operating pressure.

After a lapping operation has been completed, the control lever 4l is rocked in -a counterclockwise direction (Fig. 1) to shift the valve G3 into a reverse position so that fluid under pressure from the pump 39 passing through the pipe 42 enters the valve chamber 68 located between the valve pistons 52 and 53 and passes out thro-ugh the pipe 59 into the cylinder chamber 58. The admission of fluid under pressure to the cylinder chamber 58 causes the piston 2t and the piston rod 21 to move toward the right (Fig. 1), which movement serves through the lever mechanism above described to rock the arm 38, the roel;

shaft 2|, and the arms 2!! in a clockwise direc- 75 tion so as to move the entire lapping arm assembly to an inoperative position. During this movement fluid within the cylinder chamber Eil exhausts through the pipe 59, through the valve chamber 55 located between the valve pistons 53 and Eil, and thro-ugh the pipe 6l into the reservoir Lll.

Headstock The headstock I3 is provided with a rotatable spindle (not shown) which is supported in suitable bearings within the headstock frame. The headstock spindle may be rotated from any suitable source of power, such as an overhead belt drive or aself-contained electric motor. In the preferred construction, an electric motor 65 is mounted within the base I@ of the machine. The motor 65 is provided with a driving pulley 66 which is connected by multiple V-belts 61 with a pulley 38 on the headstock IS. The headstock construction has not been illustrated in detail in the present application, since this headstock is not considered to be a part of the present invention and, furthermore, is identical with that shown in the prior U. S. Fatent No. 2,092,734 to H. S. Indge and G. E. Hulbert dated September '7, 1937, to which reference may be had for details of construction not found herein.

A plurality of bearing lapping arms It (Fig. 1) are provided, one for finishing each main bearing on the camshaft being lapped. These lapping arms 'lll are pivotally supported on a stud 'H which is in turn supported on the upper end of an arm l2. Each of the lapping arms Tl! carries on its forward end, lapping elements '13 and ld which are arranged to engage a main bearing l5 of a camshaft 'le to be lapped. The lapping elements 13 and 'M are supported on pivotally mounted, toggle Kactuated arms, the details of which will not be described herein since these arms lll are identical with those disclosed in my prior U. S. Patent No. 2,166,009 dated July 11, 1939. The lapping elements 'F3 and "M carried by the arms lll are moved to and from operative positions by means of a. fluid pressure mechanism comprising a cylinder Tl having a piston 18 slidably mounted therein. The piston 'I8 is connected by means of a piston rod 'I9 to actuate the toggle lever so as to close the lapping element into operative engagement with the work piece before a lapping operation and to remove them therefrom after the lapping operation has been completed.

Fluid under pressure from the pump 39 within the base I of the machine passes through the pipe 42 and through a pipe {it} to a manually operable control valve ill. The valve 8l is preferably a rotary type valve having a valve rotor B2 rotatably supported within the valve casing. Fluid under pressure passing through the pipe 8% passes through a valve chamber B3 formed in the valve rotor S2 and is forced out through a pipe da which connects with a pipe or manifold 35 extending longitudinally of the machine. The manifold 35 is connected' by means of flexible pipes with the hydraulic actuating mechanism for the lapping arms 'lil (only one of the pipes and arms having been illustrated in the present case). Fluid under pressure within the manifold passes through a flexible pipe or conduit 8%, through a passage 8l, into a cylinder chamber 83, to move the piston 'I3 upwardly into the position shown in Fig. 1.

During this movement, fluid within a cylinder chamber 89 exhausts through a flexible pipe Si) into a pipe or manifold 9| which extends longitudinally of the machine. Fluid exhausts from the manifold 9 I, through a pipe 92, a valve chamber 93 formed in the valve rotor 82, and passes out through a pipe 94 which exhausts into the reservoir 4|. It will be readily apparent that in the position of the valve 8|, as illustrated in Fig. 1, the lapping elements 13 and 14 will be moved into lapping engagement with the main bearing 15 on the camshaft 16. When the valve rotor 82 is rotated one quarter turn, the direction of flow of uid under pressure will be reversed to cause the piston 18 to move downwardly toward the left (Fig. 1) to remove the lapping elements 13 and 14 from operative engagement with the main bearing 15.

A suitable support is provided for the plurality of lapping arms, that is, both the bearing lapping arms above described and the cam lapping arms to be hereinafter described. One or more slides (Figs. 1 and 2) are supported on the slide bars 22 and 23. The slide |00 is provided with an upper dovetailed surface which serves as a support for a plurality of lapping arms. If it is desired to reciprocate the lapping elements, a connecting rod |02 may be attached to each of the slides |00 (only one of which has been illustrated). The connecting rod |02 may be connected to a positively driven eccentric in a manner such as that shown in the prior patent to Indge and Hulbert No. 2,092,734 dated September 7, 1937, to which reference may be had for details of disclosure as to the reciprocating mechanism not contained herein.

In order to lap the cams on the camshaft 16 uniformly and to the desired nish, a master camshaft |04 is provided. The master shaft |04 is rotatably supported in suitable bearings carried by the arms 20. The master camshaft |04 is synchronously rotated with the product camshaft 16 to be lapped. The headstock |8 is provided With a sprocket |06 which is connected by means of a link chain |01 with a sprocket |03 rotatably supported on the rock shaft 2|. A link chain |09 also surrounds a sprocket which is formed integral with or xedly mounted relative to the sprocket |00 and serves to drive a sprocket I I0 which is connected to rotate the master camshaft |04. An idler sprocket is provided to facilitate adjustment of the tension of the chain |09. The idler sprocket is adjustably supported by means of an eccentric so that it may be readily adjusted to tension the chain |09 as desired. An idler sprocket ||2 which is rotatably `supported on an adjustable bracket I3 serves to tension the link chain |01.

A plurality of cam lapping arms are provided, one arm for each cam on the camshaft 16 to be lapped. For the sake of simplicity of illustration, only one of these lapping arms has been illustrated in detail', since the general arrangement of these arms is substantially the same as that shown in the prior U. S. patent to Indge and Hulbert No. 2,092,734, above referred to.

A plurality of cam lapping arms ||6 are provided on each of the slides |00. The cam lapping arms ||6 are spaced on the slides I0 to correpond with the spacing of a plurality of cams 5 on the camshaft 19. Each of the cam lapping arms I6 is provided with a frame ||1 having a lower dovetailed surface which mates with the dovetailed surface |0| on top of the slide |00. The frame ||1 serves as a support for a transversely slidable bar IIB. The slide bar ||8 is supported by an anti-friction support comprising nuu.)

spaced rollers ||9 and |20. The rollers ||9 and |20 are respectively supported by studs |2| and |22 carried by the frame ||1. A pair of rollers |23 and |24 are supported on studs |25 and |26, respectively. The studs |25 and |26 are supported at opposite ends of a bar |21. The rollers |23 and |24 engaging the upper surface of the slide bar ||8 cooperate with the rollers ||9 and |20 to form an anti-friction support for the transversely movable slide bar ||8. An adjusting screw |28 is screw threaded into the bracket |29 which is xedly mounted on the frame ||1 and serves to engage the bar |21 so as to adjust it in a vertical direction to take up any lost motion between the rollers ||9, |20, |23 and |24, respectively.

In order to transmit a transverse movement to the slide bar ||8 to uniformly lap the surface of the Work piece to the desired extent, a master cam roller |30 is provided for engagement with the master cam |05 on the master camshaft |04. The master cam roller |30 is supported on a stud |3|. The master cam roller |30 is ,maintained in operative contact with the master cam |05 by means of a spring |32 which is contained within an aperture formed within the slide bar ||8 and is connected at one end to a stud |33 supported by the lapping arm ||6, and at the other end is attached to a stud |34 which is xedly mounted on the slide bar ||8. The tension of the spring |32 is sufficient normally to maintain the master cam roller 30 in operative contact with the master cam |05 during the normal operation of the machine so as to transmit a transverse movement to the slide so as to produce a uniform controlled lapping action between a lapping element to be hereinafter Ydescribed and the product cam l l5 on the camshaft 16 to be lapped or finished.

The master cam roller |30 may be of a size equal to that of the lapping wheel |45, in which case the master cams may be identical in size and shape-with the cams to be produced on the camshaft being ground. If a master cam roller of `a different diameter from that of the lapping wheel |45 is utilized, then the master cams will have to be generated in order to produce the desired shape and contour on the cams being lapped.

In order to remove the cam lapping arm from an operative position after a lapping operation has been completed, a hydraulic mechanism is provided which is actuated in timed relation with the other mechanisms of the machine automatically to draw the slide I8 in timed relation with the cycle of operation. A fluid pressure cylinder |35 is iixedly mounted on the end of the slide bar i8 (Figs. 1 and 2). The cylinder |35 contains a slidably mounted piston |36 which is connected by means of a piston rod |31 with a yoke-shaped slide block |38 which supports the stud |3| and roller |30. When fluid under pressure is admitted through a pipe |39 into a cylinder chamber |40, the cylinder |35 together with the slide bar ||8 will be moved toward the right (Figs. 1 and 2) to move the cam lapping element to an inoperative position. The pipe |39 is operatively connected to the flexible pipe 90 (Fig. 1) or may be connected directly to the manifold 9|. In the position of the parts as illustrated in Fig. 1, the cam lapping arm ||6 is shown to be in an operative position.` When the rotor 82 of the valve 8| is shifted to actuate the lapping arms, fluid will be admitted through the pipe |39 into the cylinder chamber |40 to withdraw all of the cam lapping arms to an inoperative position. While only one of the cam lapping arms has been illustrated in detail, the machine may comprise a plurality of cam lapping arms, one for each cam on the camshaft being lapped, arranged substantially the same as shown in the prior U. S. Patent to Indge and Hulbert No. 2,092,734 dated September '7, 1937.

rllhe front end of the slide H8 carried by the lapping arm H5 supports a rotatably mounted, normally non-rotatable lapping element or Wheel it. This lapping wheel |45 is supported on a stud lll carried at the front end of the slide l i8. In order intermittently to present a fresh lapping surface during a lapping operation, an indexing mechanism is provided automatically to advance or index the lapping wheel M5 in timed relation With the transverse movement of the slide H8. A ratchet wheel ll'l is rotatably supported by the slide H8 on a stud lil-3. The stud Hi8 also supports a gear ille which meshes with a gear itil. The gear l5@ is supported on a stud 55 carried by the slide li. The gear 253 meshes with a gear E52 supported on a stud 53 which is also supported by the slide l it. lThe stud E53 carries a gear l5ll at its other end which meshes with a gear IE5 which is supported on the stud ll and is iixedly connected to rotate the lapping wheel M5. A holding pawl E53 supported on the slide bar H8 engages the ratchet wheel and prevents it from turning in a counterclockwise direction.

A ratchet pavvl i571 is pivotally supported by a stud EEB carried by the lapping arm llt. When the slide bar ll moves transversely toward the left under the influence of the master cam ll and the master cam roller ratchet wheel lill moves also toward the left and the pawl l5? remaining stationary, causes a partial rotation of the ratchet wheel HV1' which operates through the train of gears above described to produce a partial rotation or indexing movement of the lapping element or Wheel liii. Similarly, when the slide bar lli! moves toward the right, the ratchet wheel Ill'l is hel-d against rotation by means of the safety pawl i553 and the ratchet pawl l? rides idly over the ratchet wheel ll'l.

A modified indexing mechanism has been illustrated in Fig. 4 for indexing the lapping element or wheel E45. The lapping element M5 is rotatably supported on a stud ltd which is slidably supported in elongated slots ll formed in the spaced supporting plates it? and HB3 of the slide li. A ratchet wheel i512 is rotatably supported on the slide l lil. A sprocket l 65 is xedly mounted to rotate with the ratchet wheel It.. The sprocket 155 is connected by means of a link chain G66 with a sprocket l5?. The sprocket |67 is supported by a pair of slide blocks H53 (only one of which has been shown in Fig. 4) which are slidably supported by the slide bar H8. A peripheral surface of `a friction wheel carried by the sprocket i637 frictionally engages the periphery of the lapping wheel U35. A spring its urges the friction wheel into engagement with the periphery of the lapping wheel to turn the same as the ratchet wheel iti is indexed. A pawl Vit supported by a stud l'll is carried by the arm H6. it will be readily apparent from the foregoing disclosure that when the slide lit is moved toward the left (Fig. 4) by the master cam and follower, the ratchet wheel itil will be given a partial rotation which transmits an indexing movement to the lapping wheel H55 intermittently and automatically to present a fresh abrading surface.

ESG (Fig. 2), the

A further niodication has been illustrated in Fig. 5 in which a modiiied form of indexing mechanism has been illustrated for indexing the lapping element or wheel M5. n the modification illustrated in Fig. 5, the lapping element or wheel liil is supported on a stud 'i carried by the slide lit. A friction indexing wheel ITS is rotatably supported by a stud lll which is in turn supported by a vertically movable slide member H8 which is arranged to slide in a substantially vertical directlon within a housing HS formed on the forward end of the slide bar H8. A spring itil which surrounds the stud mi serves normally to urge the slide H8 in a downward direction to maintain the friction wheel liti in operative frictional driving engagement with the periphery of the lapping wheel ll. A ratchet wheel 182 is fixedly mounted to rotate the friction Wheel lit. A ratchet pawl iBS is pivotally supported by means of a stud llfl carried by the lapping arm Elfi. The pawl H33 is arranged automatically to transmit an indexing movement to the lapping element or wheel i655 each time the slide l i8 is moved through a complete reciprocation by means of the master cam lil and follower roller itil so as to intermittently present fresh abrading surfaces into operative lapping engagement with the cam being lapped as the lapping operation proceeds.

The operation of the improved camshaft lapping machine will be readily apparent from the foregoing disclosure. A plurality of cam lapping arms it such as shown in the drawings, are provided, one for each cam lili on the camshaft to be lapped, and a plurality of bearing lapping arms lil are provided, one for each main bearing 'l5 on the shaft it to be lapped. A camshaft 'i6 to be lapped is mounted in an operative position supported by the headstock I8 and footstock (not shown) in a manner substantially the same as that shown in the prior U. S. patent to lndge and Hulbert No. 2,092,734, above referred to. The control lever 4'! is then shifted to swing the lapping arm assembly into an operative position (Fig. 1), after which the valve rotor 32 of the control valve 3l is shifted into the position illustrated in Fig. l to admit fluid under pressure into the cylinder chambers 88 of the cylinder T8 to move the bearing lapping elements '53 and 'M into operative engagement with the main bearings l5 to be lapped. At the same time, fluid is exhausted from the cylinder chambers lilo (Fig. 2) of the cylinders |35 on each of the cam lapping arms HB to allow the released tension of the springs |32 to move the lapping elements or wheels i125 into operative engagement with the cams H5 to be lapped. The lapping operation then proceeds to the desired extent, after which the lapping elements are again moved to an inoperative position to facilitate replacement of the lapped camshaft 'I6 with a new shaft to be lapped.

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 drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a camshaft lapping machine, a cam lapping arm having a transversely movable slide, v

a master cam roller supported adjacent to one end of said slide, a master cam engaged by said' roller, said master cam and roller serving to ping arm having a transversely movable slidea rotatable master cam roller slidably supported adjacent to one end of said slide, a master cam engaged by said roller, means to maintain said roller in engagement with said cam, means to rotate said cam to impart a transverse controlled movement to said slide, a lapping wheel supported adjacent to the other end of said slide, and means including a piston and cylinder o-peratively connected between said slide and roller'whereby the slide may be withdrawn to f an inoperative position.

3. In a camshaft lapping machine, a cam lapping arm having a transversely movable slide, a rotatable master cam roller, a slide block on said slide to support said roller, a mastercam engaged by said roller, means to maintain said roller in engagement with said cam, means to rotate said cam to impart a transverse controlled movement to said slide, a lapping Wheel 5 to said slide block whereby the slide may be moved to an inoperative position.

4. In a camshaft lapping machine, a cam lapping arm having atransversely movable slide, a

masterl cam roller supported adjacent to one end of said slide, a master cam engaged by said roller, means to rotate said master cam to cause a transverse movement of said slide, means including a piston and cylinder operatively connected between said slide and roller whereby the slide may be withdrawn to an inoperative position, a normally-stationary, rotatablymounted lapping wheel supported adjacent to the other end of said slide, an index mechanism including a ratchet wheel on said slide, driving connections between said ratchet wheel and said lapping wheel, and a ratchet pawl pivotally supported on said arm which is arranged to actuate said ratchet wheel to index the lapping wheel when fluid under pressure is admitted to said cylinder to move said slide to an inoperative position. 5. In a camshaft lapping machine, a cam lapl ping arm having a transversely movable slide,

supported adjacent to the other end of said slide, a fluid pressure cylinder onA said slide, and a piston therein which is operatively connected la master cam roller supported adjacent to one end of said slide, a master cam engaged by said roller, means to rotate said master cam to cause va transversemovement of said slide, a normally..

stationary, rotatably-mounted lapping Wheel supported adjacent to the other end of said slide, an index mechanism including a ratchet wheel on said slide, frictional driving connections between saidA ratchet Wheel and said lapping wheel, and a ratchet pawl pivotally supported on said arm which isV arranged to actuate said ratchet wheel to index the lapping wheel during the movement of said slide.

l HERBERT S. INDGE.

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