US2261902A - Lapping machine - Google Patents

Description

Nov. 4, 1941.` Y Y Hv s; ,NDGE 2,261,902

LAPPING MACHINE Filed Oct. 5, 1940 2 Sheets-Sheet 1 vg s2 77 4 n GO 0 0 lsv a G' K f 76 'yq es gq 123K 85 Nov. 4, y1941. Y H. s. INDGE l2,251,902

l LAPPING MACHINE Filed Oct. 5, 1940 2 Sheets-Sheet 2 Ottawa,

Patented Nov. 4, 1941 LAPPIN G MACHINE Herbert S. Indge,

tion of Massachusetts Application October 5, 1940, Serial No. 359,921

2 Claims.

The invention relates to lapping machines, and more particularly to a lapping machine for lapping the crankpins and bearings of an automotive crankshaft.

One object of the invention is to provide an improved lap-ping machine for lapping crankpins, main bearings and the like.' A further object of the invention is to provide an improved hydraulically operated, toggle actuated lapping arm. A further object of the invention is to provide an improved lapping arm in which a flexible abrasive lapping element is employed which is automatically fed after each lapping operation to provide a fresh abrading surface for the next operation.

A further object of the invention is to provide an automatically actuated positive feed for a flexible abrasive lapping element. Another object of the invention is to provide an automatically actuated paper feeding mechanism including a pair of positively actuated, springpressed feed rollers which are actuated automatically at the end of each lapping operation. 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 drawings, in which is shown one of various possible embodiments of the mechanical features of the invention,

Fig. l is a cross sectional view through a lapping machine, showing the improved lapping arm together with a diagrammatic illustration of the hydraulic control and actuating system;

Fig,l 2 is a fragmentary side elevation, on an enlarged scale, of a lapping arm having the lapping element and parts shown in an openative position for a lapping operation;

Fig. 3 is a similar fragmentary side elevation, on an enlarged scale, of one of the lapping arms, such as shown in Fig. 2, with the lapping elements and supporting parts in an inoperative position;

Fig. 4 is a fragmentary detail view of the lower abrasive paper feed roll, taken approximately on the line 4 4 of Fig. 2;

Fig. 5 is a fragmentary front elevation of the lapping arm shown in Fig. 2, taken approximately on the line 5-5, showing the abrasive paper feed roll broken away and. shown in cross section;

Fig. 6 is a fragmentary cross-sectional View, 55

Westboro, Mass., assigner to Norton Company, Worcester,

Mass., a corporataken 'approximately on the line 6 6 of Fig. 2; and

Fig. '7 is a fragmentary detail view, taken approximately on the line 1 1 of Fig. 2, having parts broken away and shown in section to more clearly illustrate the'construotion.

A lapping machine has vbeen illustrated in the drawings comprisinga base I0 which supports a longitudinally reciprocable table H. Table ways are provided between the base l0 and table Il which in the preferred form are of an anti-friction type substantially the same as shown and described-in -my prior U. S. Patent No. 2,166,009 datedJuly 19, 1939, to which reference may be had for details of disclosure not 'contained herein. The table II serves as a support for a headstock` l2 and' a footstock (not shown) which serve as a rotatable support for a work piece I3.

The headstock l2 is preferably driven by an electric motor I5 which is mounted on the base l0. The motor l5` is provided with a multigrooved pulley I6 which is connected by multiple V-belts Il with a multi-grooved pulley I 8 which is operatively connected to rotate the headstock spindle (not shown) in a manner substantially the same as that disclosed in my prior U. S. patent above referred to.

Lapmng arm support It is desirable to provide a movable support for a plurality of lcrankpin and bearing lapping arms so that they may be simultaneously and rapidly moved into an operative or an 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 2l which is supported in bearings on the rear of the machine base l0. The arms 20 are provided with horizontally extending portions which are connected by two spaced bars 22 and 23 which serve as lslide bars vor ways for supporting a plurality of lapping arms to be hereinafter described.

The lapping arm assembly supported by the arms 20 is arranged so that it may be automatically moved to and from an operative position to facilitate loading of `crankshafts into the machine and removing them therefrom after a lapping operation has been completed. In order to move the entire lapping arm assembly to and from an operative position, a fluid pressure mechanism is provided including a fluid pressure cylinder 25 which is pivotally connected by means of a stud 26 with the base I0 of the machine. A piston 21 is slidably mounted within the cylinder 25 and is connected to one end of a piston rod 28. The other end of the piston rod 28 is connected by a stud 29 with an arm 39 pivotally mounted on a shaft 3| within the base I9. The arm, 38 is provided with a stud 32 which is connected to one end of a link 33. The link 33 is connected by a stud 34 with a toggle lever 35. One end of the toggle lever 35 is pivotally lconnected to a `Stud 36 which is fiXedly supported on the base I of the machine. The other end of the toggle lever 35 is connected by a stud 31 with a toggle `lever 38. The opposite end of the toggle lever 38 is connected by a stud 39 which is carried ybythe lower end of i an arm 49. The arm 48 is flxedly supported on the rock shaft 2I.

When fluid under pressure is admitted through a pipe 4I into a cylinder chamber 42, the piston 21 is moved downwardly into the position illustrated in Fig; 1 which serves through the toggle levers 35 and 38 to position the arm 49 and the arms 29 in the position illustrated in Fig. l. After a lapping operation has been completed, fluid under pressure is admitted through a pipe 43 into a cylinder` chamber 44 to move the piston 21 upwardly toward the right, which movement shifts the toggle levers 35 and 38 into the position illustrated in dotted lines 35a and 38a, which movement swings the arm 40 into position 49a. This movement of the arm 49 serves to rock the shaft 2I to swing the arms 29 together with the entire lapping arm assembly in a clockwise direction -to an inoperative position. f

A fluid pressure system is provided for controlling the admission of fluid under pressure to the cylinder 25. A motor driven pump 45 within the base I9 of the machine draws fluid through a pipe 46 from a reservoir 41 within the base I9 and forces fluid under pressure through a pipe 48 to a reverse or control valve 49. The valve 49 is a balanced piston type valve having a valve stem 50 which is'provided atits outer end with a spool-shaped member I and isconnected by means of a pair of diametrically opposed studs or pins 52 mounted on a lower yokeshaped end of a control lever 53. The control lever 53 is pivotally supported by means of a stud 54 on a bracket 55 which is xedly supported on the base I9 of the machine. A plurality of Valve pistons 56, 51 and 58 are formed integral with the valve stem 50. Fluid under pressure passing through the pipe 48 enters a valve' chamber located between the valve pistons 51 and 58 and passes outwardly through the pipe 4I into the cylinder` chamber 42 to move the piston 21 downwardly into the position shown in Fig. 1 to move the lapping arm assembly into an operative position. During the downward movement of the piston 21, fluid within the cylinder chamber 44 is exhausted through the pipe 43, through a valve chamber located between the valve pistons 56 and.51, and out through an exhaust pipe 59 into the reservoir 41.

After a lapping operation has been completed and it is desired to move the lapping arm assembly to an inoperative position, the manually operable control lever 53 is moved in a counterclockwise direction to shift the valve pistons 56, 51 and 58 so that uid under pressure passing through the pipe 48 enters a valve chamber located between the valve'pistons 56 and 51 and pass-es outwardly through the pipe 43 into the cylinder chamber 44 to cause an upward movement of the piston 21. This upward movement of the piston 21 shifts the toggle levers 35 and 38 together with the arm 40 into the dotted line positions 35a, 38a and 40a to rock the shaft 2I together with the arms 20 and the entire lapping assembly in a clockwise direction into an inoperative position. During this movement, fluid within the cylinder chamber 42 is exhausted through the pipe 4I, through the valve chamber located between the valve pistons 51 and 58, and passes outwardly through the exhaust pipe 59 into the reservoir 41.

Lapp'ng arms In'order that all of the crankpins and main bearings on the crankshaft I3 may be simultaneously lapped, a plurality of crankpin and bearing lapping arms are provided which correspond in number with Vthe crankpins and bearings to be lapped. As illustrated, only one of the lapping arms has been shown. For details of arrangement of the plurality of lapping arms, reference may be had to my prior U. S. Patent 2,166,009 above referred to. A side elevation of a lapping arm 69 is shown in Fig. 1. The lapping arm 69 aswell as all of the other lapping arms are each provided with a pair of pivotally mounted lap supporting arms 6I and 62 which are provided at their operative ends with partially cylindrical lap supporting blocks or elements 63 and 64, respectively. The arms 6| and 62 are pivotally supported by studs 65 and 66 on the lapping arm- 69. The other ends of the arms 6I and 62 are connected by a pair of toggle levers 61 and 6B which are connected together at.their inner ends by means of the stud 69vwhich slides in elongated slots 10 formed in the side plates of the lapping arm 69. When the toggle levers 61 and 68 are in a straightline position, as indicated in Fig. 1, the lap supporting members 63 and 64 are maintained in an operative position to hold the abrasive or lapping elements in operative contact with the work piece I3.

The lap supporting arms 6I and 62 are arranged to be moved toward and away from an operative position by means of a hydraulically operated mechanism comprising a uid pressure cylinder 15 which is mounted on the upper end of the lapping arm 69. A piston 16 is slidably mounted within the cylinder 15 and is connected to oneend of a piston rod 11. The other end of the piston rod 11 is connected by means of the link 18 with the stud 69 which is pivotally connected to the toggle levers 61 and 6B, respectively. Itwill be readily apparent from the foregoing disclosure that When the piston 16 is moved downwardly, that is, toward the left (Fig. l), the piston rod 11 and the connecting link 18 will be moved also in a downward direction toward the left, which serves to unlock the toggle levers 61 and 68 and thereby to rock the lap supporting arms 6I and 62 together with the lap supporting elements 63 and 64 to an inoperative position out of rengagement with the bearings of the crankshaft I3 to be lapped.

When fluid under pressure is passed through a flexible pipe 19 into a cylinder chamber 89, the piston 16 will be moved upwardly to move the toggle levers 61 and 68 into the position shown in Fig. l to move the lapping element into operative engagement with the work piece I3 for a lapping-operation. Similarly, when fluid is admitted through a flexible pipe 8I into the cylinder 15 to cause a downward movement of the piston 16 toward the left (Figs. 1 and 2), the toggle levers 61 and 68 will be unlocked to move the lapping elements to an inoperative position. Each of the lapping arms 60 is provided with an independent fluid operated piston and cylinder mechanism for independently actuating each of the lapping elements.

A pair of longitudinally extending pipes or manifolds 83 and 84 are provided for supplying fluid under pressure to the flexible pipes 19 and 8|, respectively, to a plurality of spaced lapping elements. The lapping arm 60 is pivotally connected by means of a stud 85 which is supported on a pivotally mounted arm 86. The arm 86 is pivotally supported by means of a stud 81 on a supporting member 88. The supporting member 88 is in turn adjustably supported on the guide rods 22 and 23, respectively. The supporting member 88 may be adjusted longitudinally relative to the rods 22 and 23 to position the arm 60 rin the desired location for lapping a predetermined portion on the work piece.

A flexible abrasive paper or cloth is preferably utilized as a lapping medium. Each of the lapping arms 60 is provided with a separate strip of continuous abrasive paper or cloth which wraps around the crankpin or main bearing to be lapped and is held in position thereagainst by the lap supporting members 63 and 64.

A rod 90 is supported by a pair of brackets 9| (only one of which is shown in Fig. 1) and serves as a support for a reel 92 of exible abrasive paper 93. The abrasive paper 93 passes through guides 94 and 95 which are xedly mounted on the under side of the supporting member 88 and pass through a series of rollers 96 carried by a bracket 91. The bracket 91 is in turn supported on the lap supporting arm 62. The abrasive paper, as above described, wraps around the crankpin I3 and is supported by the lap supporting members 63 and 64.

A manually operable control or reverse valve |05 is provided for controlling the admission to and exhaust of fluid from the cylinder 15. Fluid under pressure from the pump 45 passes through a pipe |06 into a valve chamber |01 and in the position illustrated in Fig. 1 passes out through a pipe |08, through the manifold 83, and through the flexible pipe 19, into the cylinder to move the piston 16 upwardly into the position shown in Figs. 1 and 2. During this movement iiuid within the lower cylinder chamber is eX- hausted through the flexible pipe 8|, the manifold 84, a pipe |09, through a valve chamber IIO and an exhaust pipe III, into the reservoir 41. When the valve |05 is shifted into a reverse position, that is, the valve rotor shifted ninety degrees, uid under pressure passing through the pipe |06 will pass through the pipe |09, the manifold 84, the flexible pipe 8|, into the cylinder chamber 82, to cause a downward movement of the piston 16.

The operation of this improved lapping machine will be readily apparent from the foregoing disclosure. A work piece I3, such as an automotive crankshaft, is placed in position for rotation by the headstock I2 and the footstock (not shown). The work rotation is then started and the control lever 53 is moved in a clockwise direction into the position shown in Fig. 1 to move the valve pistons so as to 'admit fluid under pressure through the pipe 4| into the cylinder chamber 42 to move the lapping arm assembly supported by the arms 20 into an operative position. After the lapping arms have moved to an operative position, the manually operable control -valve |05 is then shifted into the position illustrated in Fig. 1 so as to admit fluid under pressure through the flexible pipe 19 to cause anl upward movement of the piston 16, thus moving thev abrasive lapping element into operative lapping engagement with the work piece I3.

. As the lapping operation proceeds, the pressure is increased until the toggle levers 61 and 68 reach a straight-line position, as indicated in Fig. 1, after which the lapping operation' proceeds. After the work piece has been lapped to the required and predetermined extent, the control valve |05 is shifted into its reverse position to admit fluid under pressure through the flexible pipe 8| to cause a downward movement of the piston 16 which in turn serves to break the toggle 61-68, thereby moving the lap supporting members 63 and 64 into an open or' inoperative position. After the lapping element has been moved to an inoperative position, the control lever 53 may then be rocked in a counterclockwise direction so as to admit fluid under pressure through the pipe 43, into the cylinder chamber 44, to cause an upward movement of the piston 21 which operates through the lever mechanism above described to rock the shaft 2| and the arms 20 to swing the entire lapping arm assembly to an inoperative or loading position, after which the lapped work piece may be removed from the machine and replaced with a new work piece to be lapped. As above explained, the machine may be readily equipped with one or more of the lapping arms 60 arranged at spaced intervals along the slide bars 22 and 23 in a. manner similar to that shown in my prior U. S. Patent No. 2,166,009 above referred to.

It is desirable to provide a fresh portion of abrasive paper or cloth for each lapping operation in order that a substantially uniform lapping action may be obtained on successive work pieces. To accomplish this desired result, it is desirable to provide an automatic abrasive paper feeding mechanism which will automatically and positively advance the abrasive paper by an exact and predetermined amount for each lapping operation. It is desirable to provide a paper feeding ,mechanism which is arranged automatically and positively to feed the abrasive paper by a predetermined amount each time the lap supporting arms 6I and 62 are opened after a lapping` operation has been The abrasive paper feeding mechanism is supported by a bracket ||5 which is fastened to the lap supporting element 63 so that it moves to and from an operative position therewith. A roller II6 is rotatably supported by a stud II1 adjacent to the left-hand end of the bracket II5 (Figs. 1, 2 and 3). The periphery of the roller I I6 is provided with a corrugated or knurled surface II8. A roller II9 is rotatably supported by a stud |20 which is in turn supported on the left-hand end of a rock arm I2I. The rock arm I2I is pivotally supported on a stud |22 which is fixed relative to the bracket |I5. The periphery of the roller I I 9 is provided with a corrugated or knurled surface |23 which is yieldably urged toward the corrugated surface I I8 of the roller ||6 by means of a spring-pressed plunger |24. The compression of the spring-pressed plunger |24 may be adjusted by means of a manually adjustable screw I 25 so that a desired pressure may be exerted between the rollers I|9 and |I6. I

The continuous strip of abrasive paper, which completed.

wraps around the work piece |I3 and engages the lap supporting element 63, passes through a guide |26 which is carried by the bracket ||5. The abrasive paper 93 extends to the left beyond the guide |26 and wraps in a clockwise direction around the knurled peripheral surface ||8 of the roller H6.; Y The abrasive paper then passes through the adjacent knurled surfaces |23 and ||8 of the rollers I|9 and IIB, respectively, and Wraps in a counterclockwise direction around the roller I |9. A gear |28 is xedly mounted on the endA of the roller IIB. The gear |28 meshes with agear |29 which is, iixedly mounted on the end of the roller |9.

In order to automatically and positively indexv theabrasive lapping element. 93 by a predetermined amount after each lapping operation, an automatic indexing mechanism is provided whereby the gea-rs |29 and |28 may be readily indexed each time the lap supporting arms 6| and 62- are moved to an inoperative position.

A holding pawl is provided to at all times hold the gear |29 against rotation in a clockwise direction. An actuating pawl |31 is pivotally supported on a stud |38. The stud |38 is in turn supported by a pair of spaced rock arms |39 and |40 which are pivotally supported on the stud |20. The stud |38 is connected by a rod 4I with a bell crank lever |42. The bell crank lever |42 is pivotally supported by a stud |43. which is fixedly supported in spaced brackets |44 and |45 (Fig. '1). The brackets |44 and |45 are xedly mounted on the lower end of the lapping arm 69. The lower or short arm of the bell crank |42 is connected by a stud |46 with a link |41. The link |41 is pivotally connected by a stud |48 with a bracket |49 which is xedly mounted on the lap supporting arm 6 In Fig. 2 the lap supporting elements 63 and B4 together with the flexible abrasive lapping element 93` are shown in an operative position together with the other actuating parts thereof and with the abrasive paper feeding pawl |31 in a retracted position. When fluid under pressure is admitted to break the toggle levers 6.1 and 63, the lap supporting arm 6| moves in a clockwise direction, which movement is transmitted through the link |41 to rock the bell crank lever |42. in a counterclockwise direction so as to shift the rod |4| toward the left (Fig. 1) to move the pawl supporting arms |39 and |:4lA in a counterclockwise direction, which movement carries the paper feeding pawl |31 also in a counterclockwise direction to rotate the gears |29 and |28 in a counterclockwise and clockwise direction, respectively, to feed the abrasive forward by an exact and predetermined amount to present a portion of fresh abrasive surface for the next lapping operation. The index pawl |31 together with its actuating parts is shown in the indexed position inl Fig. 3. When the lap supporting elements 33 and 64 together withV their actuating parts are again moved into operative position with the next work piece to be lapped, the index pawl |31 rides idly over the teeth of the gear |29 to return the pawl |31 to its initial position (Fig. 2). During this movement the holding pawl |35 serves to prevent movement of the gear |29 in a clockwise direction.

The rod |4l is preferably adjustably connected to thebell crank lever |42. The bell crank lever |42' is preferably formed as two spaced parts |42. and |42a (Fig. 7).

|5I. The notch I5 serves as a support for the Thebell crank lever supports. a bracket |59; which is provided with a notch` threaded end ofthe rod |4I. A pair of spaced nuts and lock nuts |52' and |53 are arranged on opposite sides of the bracket |50 (Fig. 2). By manipulation of the nuts |52 and |53, the eiective length of the rod |4| may be readily varied as desired.

It will be readily apparent from the foregoing disclosure that each time the lap supporting elements 63 and 64 are moved to an inoperative position after a lapping operation has been completed, this movement will be automatically transmitted through the indexing mechanism above described positivelyr and precisely to index the abrasive paper 93 so as to present a predetermined portion of fresh abrasive for the next successive lapping operation. By utilizing the pair of corrugated or knurled spring-pressed feed rollers, a positive indexing movement of the flexible abrasive element is assured.

The operation of this improved lapping machine will be readily apparent from the foregoing disclosure. A work piece I3, such as an automotive crankshaft, is placed in position for rotation bythe headstock I2 and the footstock (not shown). The work rotation is then started and the control lever 53 is moved in a clockwise direction into the position shown in Fig. l to move the control valve 49 so that iiuid under pressure will pass through the pipe 4'| into the cylinder chamber 42 to cause a downward movement of the piston 21, thus rocking the entire lapping arm assembly supported by the arms 2-0 to an operative position, such as that shown in Fig. 1.l The valve |35 is then shifted into the position illustrated in Fig. l to move the lap supporting elements. 63. and 64 into an operative position to wrap the flexible abrasive paper or lapping element 93 around the periphery of the surface to be lapped.

The indexing mechanism above described having previously advanced the paper 93 by a precise andpredetermined amount, the closing of the lap supporting elements 63 and 641 serves to advance the abrasive paper 93 from the supply roller 92. The lapping operation thenproceedsto the desired and, predetermined extent, after which the valve |95 isy shifted so as to admit fluid under pressure throughthe flexible pipe 8| to cause a downward movement of the piston 16, which movement breaks the toggle levers 61 and 68 and moves the lap, supporting elements 63 and 64 into an inop erative position away from the work piece I3. During this movement, the index pawl |31 is automatically moved in a counterclockwise direction to rotate the gear |29 in a counterclockwise direction and the gear |28 in a clockwise direction, thusA advancing the abrasive paper 93 by a precise and predetermined amount to present a predeterminedl fresh abrasive surface for the next lapping operation. As above explained, the machine may be readilyy equipped with one or more lapping arms 30 arranged at spaced intervals along the supporting bars 22 and 23 in a manner similar to that shown in my prior U. Si. Patent No. 2,166,009-above referred to.

It will thus be seen that there has been providedv by this4 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 a75. matter hereinbefore. set forth or'shown in the. ac-

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

I claim:

1. In a lapping arm for lapping cylindrical work pieces, a exible strip of abrasive to loop around a work piece, a pair of opposed jaws having surfaces arranged to clamp said abrasive in abrading contact with a workpiece, means to move said jaws to and from an operative position, guiding rollers supported by one of said jaws, a pair of opposed rough-surfaced, spring-pressed rotatable feed rollers supported by the other jaw, means to adjust the relative pressure between said rollers, gearing operatively connecting said rollers, means including a pawl engageable with said gearing, and means including adjustable connections between said pawl and one of said jaws which is actuated by movement of said jaws to an inoperative position automatically to actuate said pawl and index said abrasive by a precise and predetermined amount.

2. In a lapping arm for lapping cylindrical work pieces having a exible strip of abrasive to loop around a work piece, a pair of pivotally mounted opposed shoes to support the abrasive element in abrading contact with the work piece, a pair of toggle levers to move said shoes to and from an operative position, and an abrasive element feeding mechanism including an abrasive guiding device supported by one of said jaws, a pair of opposed rough-surfaced, spring-pressed rotatable feed rollers supported on the other jaw, said abrasive element passing between said rollers, gearing operatively connecting said rollers, means including an index pawl engageable with said gearing, means including a pivotally mounted lever which is adjustably connected to actuate said pawl, and operative connections between said lever and one of said toggle levers which is actuated automatically by movement of said toggle levers to an inoperative position automatically to actuate said pawl and feed said abrasive element a precise and predetermined amount.

HERBERT S. INDGE.

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