US2761261A - Crankpin grinding apparatus - Google Patents

Description

J. A. SILLS CRANKPIN GRINDING APPARATUS Filed Jan. l5, V1953 NM, mm. mm,

Sept. 4, 1956 INVENToR. 'Joseph A. Sil/s. BY m, @am wm lf/ys. Y

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.N @Fi Unite States tent @hice 2,761,261 iiettentetl Sept. 4, 1956 2,751,261 CRQIN GllNG APPARATUS Joseph A. Stills, St. Qharles, lil. Application January 13, 1953, Serial No. 330,994 10 Claims. (Cl. dl-njiil) The present invention relates to apparatus for regrinding and renishing the crankpin on a crankshaft of an internal combustion engine, or the like, while the :crankshaft is in its normal position supported by its main bearings in the engine block, and while the crankpin is operatively connected by a connecting rod to its piston arranged in its cylinder in the block, and more particularly t improve apparatus of the character of that disclosed in the copending No. 320,029, No. 2,670,578, March 2, 1954.

The apparatus disclosed in the Sills application mentioned comprises a cap that is detachably secured to the crank end of the connecting rod and embracing the crankpin, two bearing members respectively carried by the crank end of the connecting rod and by the cap and respectively engaging the opposite sides of the crankpin for the purposes of clamping the crankpin in place and of operatively connecting the crankpin to the connecting rod, and two grinding elements respectively carried by the two bearing members and respectively engaging the opposite sides of the crankpin in grinding relation therewith. In the arrangement, rotation of the crankshaft not only produces a grinding action by the grinding elements engaging the crankpin, but causes reciprocation of the piston in the cylinder through the connecting rod; whereby the normal cooperation between the piston and the cylinder positively establishes proper alignment between the crankpin and the cylinder as the grinding action proceeds.

While this arrangement is entirely satisfactory in regrinding and refinishing crankpins that are normally worn, it is subject to the criticism that considerable time is consumed in regrinding and refinishing crankpins that are badly worn and deeply scored.

Accordingly, it is a general object of the present invention to provide improved grinding and finishing apparatus of the character described, that incorporates a power-driven grinding wheel, so that a badly worn and deeply scored crankpin may be rapidly and accurately reground and reiinished with positive assurance that it will be in proper alignment with its cylinder in the block.

Another object of the invention is to provide grinding apparatus of the character described, that incorporates an improved and simplified arrangement for positively preventing backlash between the crankpin and the apparatus as a consequence of rotation of the crankshaft and of reciprocation of the connected piston in its cylinder in the block during the grinding action.

A further object of the invention is to provide grinding apparatus of the character described, that incorporates an improved and simplified arrangement for accommodating adjustment of the position of the grinding wheel toward and away from the center line of the crankpin during the grinding action.

A further object of the invention is to provide grinding apparatus of the character described, that incorporates an improved and simplified arrangement for accommodating adjustment of the position of the grinding wheel along the surface of the crankpin longitudinally of the center line thereof during the grinding action.

A further object of the invention is to provide grinding apparatus of the character described, that comprises a minimum number of simple parts that are largely interchangeable to accommodate the grinding of crankpins on the crankshafts incorporated in a Wide variety of internal combustion engines.

A further object of the invention is to provide grinding apparatus of the character described, that is of such compact construction and arrangement that even crankpin No. 1 on the crankshaft of an internal combustion engine mounted in a low-slung frame of' an automobile may be reground and reiinished, without removal of the engine from the frame, and without disassembly of the normally interfering front-end suspension and steering mechanism of the automobile.

Further features of the invention pertain to the particular arrangement of the elements of the grinding apparatus, whereby the above-outlined and additional operating features thereof are attained.

The invention, both as to its organization and method Figure l is an upstanding lateral sectional view of an internal combustion engine of the L-head type and ncorporating grinding and finishing apparatus, as well as a fragmentary side View of the associated electric motor drive unit for the apparatus, and embodying the present invention;

Fig. 2 is an enlarged plan View of the apparatus shown in Fig. 1;

Fig. 3 is an enlarged vertical sectional View of the apparatus, taken in the direction of the arrows, along the offset line 3-3 in Fig. 2;

Fig. 4 is an enlarged fragmentary vertical sectional view of a portion of the apparatus, illustrating the arrangement for mounting one of the guide plungers incorporated therein Fig. 2;

Fig. 5 is an enlarged horizontal sectional View of another portion of the apparatus, illustrating the arrangement of the latch ring for retaining the adjusted position of the grinding wheel in its supporting iixture, this` figure being taken in the direction of the arrows along the line 5 5 in Fig. 3;

Fig. 6 is an end View of the plug connector incorporated in the apparatus, as shown in Figs. 1 and 3; and

Fig. 7 is an end view of the detachable socket connector forming a part of the associated motor drive unit for the apparatus, as shown in Fig. 1..

Referring now to Fig. 1 of the drawing, there is illustrated ay conventional internal combustion engine 10 of the L-head type, including a block 11, a head 12 detachably secured to the top of the block 11, and an oilpan, not shown, that is adapted normally to be detachably secured to an outwardly directed flange 13 provided about` the bottom of the block 11, the lower portion of the block il and the oilpan normally cooperating to dene a `crankcase 14 housing a crankshaft 15' mounted for rotation upon main bearings, not shown, carried by the block 11. The block 11 is provided with cylinders 16, etc., in which pistons 17, etc., are arranged; and the crankshaft 15 is provided with crankpins iS, etc., that are `connected to the pistons 17, etc., by connecting rods 19, etc., and wristpins 20, etc. As illustrated, the lower end of the connecting rod 19 terminates in a iiange 21 carrying an upper bearing member 22 and normally connected to a detachable bearing cap, member; whereby the crankpin 18 is normally embraced by the two bearing members mentioned. Finally, the engine comprises the usual domes 23, etc., poppet valves 24, etc., and threaded sparkplug receiving holes 25, etc.

Now in the event it becomes necessary to regrind or refinish the crankpin 18, the oilpan, not shown, is removed from the bottom of the block 11, followed by the removal of the bearing cap, carrying the lower bearing member, not shown, from the flange Z1. The grinding apparatus, indicated generally at 311, is then assembled upon the crankpin 18 and the flange Z1; and thereafter the grinding and finishing operation is carried out, by rotating the crankshaft 15, while the crankshaft is supported by its main bearings, not shown, in the block 11, and while the crankpin 13 is connected by the connecting rod 19 to thepiston 17, and by operation of the grinding apparatus 30, as explained more fully hereinafter.

More particularly, the apparatus 30 comprises a yokelike cap 31 provided with two laterally spaced-apart and outwardly directed flanges 32 having upstanding holes 33 formed therein and receiving cap screws 34 detachably securing the cap 31 in place upon the flange 21 provided adjacent to the crank end of the -connecting rod 19. As best shown in Figs. 2 and 3, the cap 31 has a laterally extending substantially semi-cylindrical passage 35 formed through the upper end thereof and arranged to accommodate the adjacent portion of the crankpin 18, and includes a depending barrel 36 having an upstanding substantially cylindrical cavity 37 formed therein and communicating at the upper end thereof with the passage 35, the barrel 36 having laterally spaced-apart and upstanding openings 38 formed therein and communicating with the opposite sides of the cavity 37. Also, as best shown in Figs. 2 and 4, four upstanding holes 39 are formed in the barrel 36 exteriorly of the cavity 37 and communicate at the upper ends thereof with the passage 35, the holes 39 being arranged in a substantially rectangular pattern. Four upstanding guide plungers 40 are respectively slidably mounted in the four holes 39 and biased upwardly toward the adjacent surface of the crankpin 18 by four coil springs 41 respectively engaging the lower ends thereof. More particularly, as best shown in Fig. 4, each of the holes 39 is provided with a counterbore 42 adjacent to the lower end thereof that receives the 4associated coil spring 41; and each of the plungers 40 is provided with a head 43 arranged in the associated counterbore 42 and directly engaging the adjacent end of the associated coil spring 41. The coil springs 41 are retained in place by two laterally spaced-apart and longitudinally extending cover plates 44 secured in place upon the end of the barrel 36 by respective pairs of screws 45. The upper end of each of the plungers 40 is beveled, as indicated at 46 in Fig. 4, so as to provide a bearing surface engaging the adjacent surface of the crankpin 18. In view of the above description of the arrangement of the four plungers 40 slidably mounted in the four holes 39 provided in the barrel 36, it will be understood that when the cap` 31 is secured in place upon the flange 21 by the cap screws 34, the bearing surfaces 46 provided on the upper ends of the plungers 40 engage the adjacent surface of the crankpin 18, thereby securely clamping the crankpin 18 in place between the upper ends of the plungers 40 and the upper bearing member 22 carried by the flange 21, the springs 41 being compressed for the purpose of biasing the plungers 40 into firm engagement with the adjacent surface of the crankpin 18. This arrangement positively secures the crank pin 18 in clamped relation between the cap 31 and the ange 21 provided on the crank end of the connecting fod 19 eliminating any backlash between the crankpin 18 and the cap 31 or between the crankpin 18 and the crank end of the connecting rod 19 and operatively connecting the crankpin 1-8 through the connecting rod 19 and the wristpin 20 to the piston 17.

Also a pair of laterally spaced-apart and longitudinally not shown, carrying a lower bearing extending stops 47 are secured to the flange 32 within the adjacent top portions 0f the passage 35; which stops 47 engage the opposite ends of the upper bearing member 22 for the purpose of positively anchoring it in place during rot-ation of the crankshaft 15, as explained more fully hereinafter. Further, an upstanding substantially annular grinding wheel 48 is arranged within the cavity 37 and secured at the bottom end thereof to a plug 49 that is mounted for rotation about la substantially vertical axis, the body of the wheel 48 being formed of Carborundum or other suitable grinding material. More particularly, as best shown in Fig. 3, la substantially centrally disposed bore 5@ is formed in the bottom end Wall of the barrel 36 and receives a substantially cylindrical bushing 51 rotatably mounted therein. The top end of the bushing 51 is provided with an outwardly directed annular flange 52 overhanging the adjacent top end of the bore 50, and the bottom end of the bushing 51 is threaded and receives an annular internally threaded latch ring 53; whereby the bushing 51 is removably secured in place in the bore 50 for rotation therein. Cooperating threaded holes are provided in the bushing 51 adjacent to the bottom end thereof and in the latch ring 53, and receive a removable set screw 54 that securely iixes the relative positions of the bushing 51 and the latch ring 53. An elongated vertically extending threaded opening 55 is formed in the bushing 51 in a position laterally offset from and substantially parallel to the vertical axis of the bore 50; whereby the center line of the opening 55 is eccentric with respect to the center line of the bore 50.

Further, the apparatus 30 comprises a sleeve 56 terminating in an exteriorly threaded top end engaging the threaded opening 55, the body portion of the sleeve 56 projecting downwardly below the latch ring 53. The sleeve 56 is provided with an elongated vertically disposed cylindrical bore 57, the axis `of which is concentric with the axis of the threaded opening 55; which bore 57 receives and rotatably supports a spindle 58. The interior of the spindle 58 has a threaded opening 59 formed therein that terminates adjacent to the bottom end thereof in a pocket 60 constituting an oil reservoir and containing fibrous material 61 impregnated with an appropriate lubricating oil, appropriate holes 62 being provided in the body of the spindle 57 between the oil reservoir 61 and the surface of the bore 57 for the purpose of lubrication. The interior of the plug 49 is provided with an elongated vertically disposed threaded opening 63, the axis of which is disposed concentric with the axis of the threaded opening 59. Finally, a connector 64 operatively connects the plug 49 to the spindle 58, the top end of the connector 64 being threaded and engaging the threaded opening 63 provided in the plug 49, and the bottom end of the connector 64 being threaded and engaging the threaded opening 59 provided in the spindle 58. Accordingly, it will be understood that the grinding wheel 48 and the mounting plug 49 therefor are detachably secured to the connector 64; and likewise the connector 64 is detachably secured to the spindle 58.

The extreme bottom end of the spindle 5S terminates in a fixture 65 having a bore therein that carries a tube 66; which elements comprise a composite chuck fixture adapted to be engaged by an appropriate chuck fixture, carried by a detachable motor drive unit. Similarly, the intermediate barrel portion 67 of the sleeve 56 is threaded for the purpose of engagement with a detachable connector carried by the motor drive unit. As indicated in Fig. l, the motor drive unit that is detachably secured to the apparatus 30 may consist essentially of a highspeed electric motor 68 provided with an operating shaft 69 and an associated exible connector including an outer protective sheath 70 and an inner housed flexible drive cable 71, the inner end of the sheath 70 terminating in a fixture 72 appropriately connected to the drive motor 68, and the outer end of the sheath 70 terminating in a fixture 73 appropriately connected to the threaded portion 67 of the sleeve 56.

More particularly, 73 comprises an outer threaded as indicated as shown in Fig. 7, the connector tubular sleeve 74 that is internally at '75, and arranged to engage the sleeve 56. Also the tubular priately secured to the sleeve 56, the cavity 76' receives the element 65 and the pin 77 projects into the tube 66 in order to provide the drive connection between the fixture 76 and the bottom end of the spindle 58. The relationship between the respective parts carried by the connector 73, by the sleeve 56 and by the spindle 58 is shown in Figs. 6 and 7; whereby it will be understood that when the connector 73 is in place with respect to the sleeve 56, the drive fixture 75 provided on the outer end of the drive cable 71 appropriately rotates the spindle 5S and consequently the connector 64 and the grinding wheel 48 at a very high speed of about 22,000 R. P. M. Of course the electric motor 68 may be selectively energized for the purpose of selectively rotating the grinding wheel 48 through the cable 71. Also, it will be understood that the sheath '7d may be rotated manually by gripping the xture 73 so as to effect a corresponding manual rotation of the sleeve 56, for a purpose more fully explained hereinafter.

For the purpose of adjusting the position of the grinding wheel 48 toward and away from the surface of the crankpin 18 the sleeve 56 may be rotated in corresponding directions with respect to the bushing 51, the threaded top end of the sleeve 56 engaging the threaded opening 55 provided in the bushing 51; whereby the spindle 58, the connector 64, the plug 49 and the grinding wheel 48 travel with the sleeve 56. The adjusted position of the grinding wheel 58 with respect to the bushing 51 is preserved by a latch arrangement, including a latch pin 78 provided in a cavity 79 formed in the bushing 51, a coil spring 80 being arranged in the cavity 79 and engaging the top end of the latch pin 78. More particularly, as shown in Figs. 3 and 5, the coil spring 80 urges the latch pin 78 downwardly so that a reduced cylindrical latch portion 81 formed on the extreme bottom end thereof rides into one of a plurality of cooperating shallow cylindrical holes 82 formed in the adjacent top end of the sleeve 56 constituting a latch ring. Specifically, the shallow holes 82 formed in the top end or latch ring of the sleeve 56 are arranged in closely spaced angular relation thereabout for individual cooperation with the latch portion 81 of the latch pin 78 so as to preserve the adjusted rotary position of the sleeve 56 with respect to the bushing S1. Of course, it will be understood that the latch pin 78 may be pushed upwardly by engagement with a screw driver, or the like, against the bias of the coil spring 80, so as to cause the latch portion 81 thereof to disengage the aligned one of the holes 82 formed in the sleeve 56 in order to release the sleeve S6 for rotation with respect to the bushing 51.

As previously noted, the bushing 51 is rotatable in the bore S8; whereby the sleeve 56, the spindle 58, the connector 6d, the plug 49, and the grinding wheel 48 carried thereby are rotated therewith eccentrically with respect to the center line of the bore 50; whereby the position of the grinding wheel 48 is adjusted along the surface of the crankpin 18 longitudinally of the center line thereof. For the purpose of retaining the adjusted rotary position of the bushing 51 with respect to the barrel 36, an arrangement is provided that includes a friction pin 83 mounted in a hole 84 provided in the end of the barrel 36 and biased downwardly by a cooperating coil spring 85, as shown in Fig. 3. More particularly, the eXtreme bottom end of the friction pin 83 is substantially bulbous and enters into any one of a plurality of angularly disposed depressions 86 formed in the top of the latch ring 53. Specifically, the arrangement including the friction pin 83 prevents free rotation of the bushing 51 within the bore 50 as a consequence of operation of the drive motor 68, but accommodates rotation of the bushing 51 within the bore Sil, `as a consequence of manual forceable rotation vof the connector 73. In other words, the normal rotative force Si as a consequence of the operation of the drive motor 68 -does not rotate the bushing 51, but the operator may readily rotate the bushing :'51 by exerting a rotative force manually upon the connector 73. This arrangement accommodates the adjustment of the position of the grinding wheel 48 along the surface of the crankpin 18 longitudinally of the center line thereof, as previously noted.

In order to assemble the apparatus 30 upon the crankpin 18 and the flange 21, the cap 31 is brought into place in straddling relation with respect to the crankpin 18 (instead of the usual lower bearing cap); and the cap screws 311 are set securely to retain the cap 31 in place, At this time, it may be assumed that `the grinding wheel i8 occupies its retracted position with respect to the adjacent surface of the crankpin `18 and that the drive motor 68 is operated. The operator eiects the retraction of the latch pin 78 and rotates the sleeve 56 so as to move the grinding wheel 48 toward the adjacent surface of the crankpin 18; and when light contact is established between the top end of the grinding wheel 48 and the adjacent surface of the crankpin 1S, the operator effects the projection of the latch pin 78 so as to retain the adjusted position of the sleeve 56 with respect tothe bushing 51. The operator then brings about rotation of the crankshaft 15 at a slow speed so that a grinding action takes' place between the top of the grinding wheel 48 and the surface of the crankpin 18. As the grinding action proceeds, the operator rotates the bushing 51 in the bore 50 by grasping the connector 73 and exerting a rotative force thereupon so that `the position of the grinding wheel 48 with respect to the t surface of the crankpin 18 is adjusted back and forth therealong. After this grind or cut has been taken, the operator arrests rotation of the crankshaft 15 and effects further adjustment of the sleeve 56 with respect to the bushing 51, after releasing the latch pin '78; whereby another grind `or cut is established between the top end of the grinding wheel 48 and the surface of the crankpin 18. Again rotation of the crankshaft 15 is effected; and rotation of the 4sleeve 56 is brought about so that this grind or cut is produced along the surface of the crankpin 18. in carrying out the grinding action, the crankshaft 1S should be rotated at a relatively low speed by an appropriate motor drive, or the like, not shown.

During the grinding operation, proper alignment between the reground and refinished surface of the crankpin 18 and the cylinder 16 normal cooperation between the piston 1'7 and the cylinder 16, the guided reciprocatory motion of the piston 17 being transmitted via the connecting rod 19 to the apparatus 30. Also it will be understood that the arrangement including the plungers 40 prevents backlash between the crankpin 18 and the grinding wheel 48 incident to rotation of the crankshaft 15 during the grinding operation.

In connection with the operation of the apparatus 38, it is emphasized that since the grinding wheel 48 is rotated at a very high speed by the external electric drive motor 68, very substantial grinds or cuts may be taken upon the surface of the crankpin 18 in a ready manner so that badly damaged and deeply scored crankpins may be reground and refinished very quickly. Moreover since the apparatus 30 is exceedingly compact and is connected directly to the crank end of the connecting rod 19, it may be employed in regrnding and renishing crankpin No. 1 on the crankshaft of `an internal combustion engine mounted in a low-slung frame of an automobile, without removal of the engine from the frame, and without disassembly of the normally interfering front-end suspension and steering mechanism of the automobile; which arrangement is most advantageous since no limitation is imposed upon the utilization of the apparatus 30 in regrinding and refinishing crankpins.

Further, it will be appreciated that in the use of the apparatus 30y different grinding wheels 48 may be required with regard to size, shape and composition in the regrinding and refinishing of crankpins incorporated in different engines. Morover, different caps 31 are required in conjunction with the regrinding and refinishing of the crankpins in different engines, as it will be appreciated that the diameters, lengths and throws of the crankpins in different engines vary considerably. However, the apparatus 30 comprises a relatively small number of individual elements which are highly interchangeable so that with a few extra caps 31, grinding wheels 48, etc., the required assembly may be readily devised for the purpose of regrinding and refinishing the crankpin on virtually any engine.

In view f the foregoing, it is apparent that there has been provided improved apparatus for regrinding and refinishing the crankpin on a crankshaft while the crankshaft is supported in its main bearing in the engine block and while the crankpin undergoing the grinding operation is operatively connected to its piston arranged in its cylinder in the engine block; whereby the mere rotation of the crankshaft positively insures that the reground and refinished surface on the crankpin undergoing the grinding operation is positively in alignment with its associated cylinder by virtue of the fact that the guided reciprocatory movement of the connected connecting rod compels the alignment mentioned. Furthermore, the grinding proceeds very rapidly by virtue 0f the independent and external drive of the grinding wheel at the very high speed by the associated electric motor drive unit.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein, and it is intended to cover in the appended claims all such modifications as fall Within the true spirit and scope of the invention.

What is claimed is:

l. In combination with an engine including a block provided with a cylinder and main bearings, a crankshaft supported by said main bearings and provided with a crankpin, a piston arranged in said cylinder, and a connecting rod extending between said crankpin and said piston; apparatus for grinding said crankpin with said crankshaft in its supported position and with said connecting rod in its extending position and comprising a cap, means for detachably securing said cap to the crank end of said connecting rod in a position disposed below said crankpin and in straddling relation therewith, said cap having a cavity formed in the upper portion thereof adjacent to and below said crankpin, means including a bearing member carried by said cap and engaging said crankpin for clamping said crankpin in place between the crank end of said connecting rod and said cap, a rotatably mounted grinding wheel carried by said cap and arranged within said cavity and positioned below said crankpin, means for selectively moving said grinding wheel with respect to said cap into and out of engagement with said crankpin, and means for rotating said grinding wheel during rotation of said crankshaft to produce a grinding action upon said crankpin, the normal cooperation between said piston and said cylinder incident to rotation of said crankshaft establishing proper alignment between said crankpin and said cylinder as the grinding action proceeds.

2. The combination set forth in claim l, wherein said bearing member essentially comprises a plurality of plungers slidably carried by said cap and resiliently biased into engagement with said crankpin in order to clamp said crankpin in place between the crank end of said connecting rod and said cap.

3. The combination set forth in claim 1, wherein said grinding wheel is mounted upon said cap for rotation about an axis substantially normal to that of said crankpin.

4. In combination with an engine including a block provided with a cylinder and main bearings, a crankshaft supported by said main bearings and provided with a crankpin, a piston arranged in said cylinder, and a connecting rod extending between said crankpin and said piston, apparatus for grinding said crankpin with said crankshaft in its supported position and with said connecting rod in its extending position and comprising a cap, means for detachably securing said cap to the crank end of said connecting rod in a position disposed below said crankpin and in straddling relation therewith, said cap having a cavity formed in the upper portion thereof adjacent to and below said crankpin, means including a bearing member carried by said cap and engaging said crankpin for clamping said crankpin in place between the crank end of said connecting rod and said cap, an upstanding spindle carried by said cap and mounted for rotation in an opstanding opening provided therein and communicating with said cavity, a Grinding wheel detachably secured to the upper end of said spindle and arranged within said cavity and positioned below said crankpin, and means for selectively moving said spindle in said upstanding opening in said cap so as selectively to move said grinding wheel into and out of engagement with said crankpin, the lower end of said spindle projecting from said upstanding opening in said cap and being adapted to be detachably engaged by a rotatable drive element so as to accommodate rotation thereof and the consequent rotation of said grinding wheel during rotation of said crankshaft in order to produce a grinding action upon said crankpin, the normal cooperation between said piston and said cylinder incident to rotation of said crankshaft establishing proper alignment between said crankpin and said cylinder as the grinding action proceeds.

5. The combination set forth in claim 4, wherein said apparatus further comprises means for selectively adjusting the position of said spindle longitudinally of the axis of said crankshaft.

6. In combination with an engine including a block provided with a cylinder and main bearings, a crankshaft supported by said main bearings and provided with a crankpin, a piston arranged in said cylinder, and a connecting rod extending between said crankpin and said piston; apparatus for grinding said crankpin with said crankshaft in its supported position and with said connecting rod in its extending position and comprising a cap, means for detachably securing said cap to the crank end of said connecting rod in a position disposed below said crankpin and in Istraddiing relation therewith, said cap having a cavity formed in the upper portion thereof adjacent to and below said crankpin, means including a bearing member carried by said cap and engaging said crankpin for clamping said crankpin in place between the crank end of said connecting rod and said cap, said cap being provided with an upstanding bore therein positioned below said crankpin and communicating with said cavity and having an axis substantially normal to the axis of said crankpin, an upstanding bushing rotatably mounted in said ups'tanding bore and provided with an elongated upstanding opening therein having an axis offset from and substantially parallel to the axis of said opstanding bore, an ups-tanding spindle mounted for rotation in said upstanding opening, a grinding wheel carried by the upper end of said spindle and arranged within said cavity and positioned below said crankpin, rotation of said bushing effecting movement `of said grinding wheel longitudinally along the surface of said crankpin, means for rotating said bushing, rotation of said spindle during rotation of said crankshaft causing said grinding wheel to produce a grinding action upon the surface of said crankpin, and means for rotating said spindle, the normal cooperation between said piston and said cylinder incident to rotation of said crankshaft establishing proper alignment between said crankpin and said cylinder as the grinding action proceeds.

7. The combination set forth in claim 6, wherein said apparatus further comprises means for selectively restraining said bushing in the different rotary positions thereof.

8. In combination with an engine inclu-ding ablock provided with a cylinder and main bearings, a crankshaft supported by said main bearings and provided with a crankpin, a piston arranged in said cylinder, necting rod extending between said crankpin and said piston; apparatus for grinding said crankpin with said crankshaft in its supported position and with said connecting rod in its extending position and comprising a cap, means for detachably securing said cap to the crank end of said connecting rod in a position disposed below said crankpin and in straddling relation therewith, said cap having a cavity formed in the upper portion thereof adjacent to and bel-ow said crankpin, means including a bearing member carried by said cap and engaging said crankpin for clamping said crankpin in place between the crank end of said connecting rod `and said cap, said cap being provided with an upstanding bore therein positioned below said crankpin and communicating with said cavity and having an axis substantially normal 'to the axis of said crankpin, an opstanding bushing rotatably mounted in said upstanding bore and provided with an elongated upstanding threaded opening Itherein having an axis offset from and substantially parallel to the axis of said upstanding bore, lan upstanding sleeve having a threaded upper end rotatably mounted in Vsaid upstanding threaded opening and provided with an elongated upstandin-g bearing opening therein having an axis substantially concentric with the axis of said upstanding threaded opening, an upstanding spindle mounted for rotation in said upstanding bearing opening, a grinding Wheel carried by the upper end of said spindle and arranged within said cavity and positioned below said crankpin, rotation of said bushing effecting movement of said grinding wheel longitudinally along the surface of said crankpin, means for rotating said bushing, rotation of said sleeve in opposite directions effecting corresponding movements of said grinding wheel toward and away from the surface of said crankpin, means for selectively rotating said sleeve in opposite directions, rotation of said spindle with said grinding wheel in engagement with the surface yof said crankpin and during rotation of said crankshaft causing said grinding wheel to produce 'a grinding action upon the surface of said crankpin, and means for rotating `said spindle, the normal cooperation between said piston and said cylinder incident to rotation of said crankshaft establishing proper alignment between said crankpin and said cylinder as the grinding action proceeds.

9. The combination set forth in claim 8, wherein said apparatus further comprises means for selectively restraining said sleeve in the diiferent rotary positions thereof.

10. The combination set forth in claim 8, wherein said apparatus further comprises a drive unit including an elongated flexible sheath and an elongated exible element arranged within said sheath and rotatable with respect thereto, means for detachably securing the outer end of said sheath to the lower end of said sleeve, and means for detachably securing the outer end of said element to `the lower end of said spindle.

References Cited in the tile of this patent UNITED STATES PATENTS

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