US2012263A - Crank shaft grinding machine - Google Patents

Description

Aug 27, 1935. c. H. AMlDON CRANK SHAFT GRINDING MACHINE Filed Sept. 19, 1954 4 Sheets-Sheqt l Aug. 27, 1935. c. H. AMIDON CRANK SHAFT GRINDING MACHINE Filed Sept. 19, 1934 4 Sheets-Sheet 2 1lllllllllllllllllllllll'lllh 3 ill 93 Aug. 27, 1935. c H A lb N 2,012,263

CRANK SHAFT GRINDING MACHINE Filed Sept. 19, 1934 1 4 Shegts-Sheet 3 Aug. 27, 1935. A D N 2,012,263

CRANK SHAFT GRINDING MACHINE '7 'Filed Se pL 19; 1934 4 Sheets-Sheet 4 Patented Aug. 27, 1935 UNITED STATES 2,012,263 I CRANK SHAFT (mmnmc MACHINE Charles H. Amidon, Worcester, Mass, assignor.

to Norton Company, Worcester, Mass, a corporation of Massachusetts Applicatiomseptember 19, 1934, Serial No. 744,109

13 Claims.

The invention relatesto grinding machines,

. and with regard to its more specific features to a grindingmachine for grinding crank shafts.

One object of the invention is to provide a grinding machine capable of grinding irregular bodies at a high rateof production. Another object of the invention is to provide a grinding machine capable of grinding all throws of a crankshaft at a single operation. Another object of the invention is to provide a grinding machine adapted to grinding cranks and similar articles to a high degree of precision. Another object of the invention is to provide a highly efiicient grinding machine. Another object of the invention is to provide a grinding apparatus adapted to produce precision results without the use of work-rests, thus simplifying the grinding 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, illustrative of one of various possible embodiments of the mechanical features of this invention,

Figure 1 is a front elevation;

Figure 2 is an end elevation, the machine being viewed as from the left-hand side of Figure 1, certain machine parts being shown as I broken away to show other mechanism;

I Figure '3 is a viewon an enlarged scale of a device for holding the axis of each grinding wheel at any one of a plurality of points in its orbital path for use when it is desired to true one or more of the grinding wheels; I f

Figure 4 isa'fragmentary view-showing the wheel truing or dressing device;

Figure 5 is a detailed view showing a pair of grinding wheels and their mountings, one wheel and its support being illustrated in .section;

Figure 6 is a diagrammatic view illustrating the grinding of a crankshaft and the driving trains for wheel rotation, wheel orbital movement, and workpiece rotation; v

Figure 7 is an enlarged view, similar to Figure 5, showing a modified form of wheel mounting whereby the planes of rotation of the sev eral wheels may be adjusted relative to each other by a small amount;

Figure 8 is a sectional view taken on the line 8--8 of Figure '7.

As conducive to a clearer understanding of the present invention, I note that the regular practicein grinding crankshafts has involved the grinding of the several pins or throws successively. Machines which have heretofore been provided for grinding crankshafts according to such method have included mechanisms for successively positioning the same wheel against different throws and for supporting the work-piece. With the very best arranged and organized of such machines the setting up for grinding of successive' crank-throws has nevertheless involved a substantial amount of time. The present invention succeeds in performing at a single operation successfully that which, according to the usual prior practice required a plurality of operations.

Referring now to Figures 1 and 2, I provide a machine base I l upon which'is mounted a table or carriage l2 by means of suitable ways on the under side of the table, not shown, and cooperating ways l3, l4 formed in the machine base II. The table or carriage l2 may be moved longitudinally of the machine base .I l by means of a hand wheel l5 which is connected, through suitable gearing not shown, to a driving gear l6 that meshes with a rack I'I fastened to the under side of the table or carriage l2, Although, so far as certain fea- .which is here shown as an automobile crankshaft,

is carried by centers 2| and 22, the latter being mounted in the usual adjustable tail-stock 23 having a hand towards and away from the-work-piece, together with locking device 25 to lock the center 22 in adjusted position. This tail-stock 23 is in turn adjustably mounted for movement parallel to the axis of rotation of the work-piece on thetable l 2, and may be secured in adjusted position by means of clamping bolts 26 In order that this machine may be to a large extent universal and to facilitate removal of the machine parts from the base when desired, and for simplicity in setting up the machine, I prefer to mount the head center 2| in a head-stock 30 which is independent of the table l2 but which wheel 241:0 move the center 22 table I2 rests upon and which head-stock has cooperating ways formed therein and designated by the numerals 3| and 32 on Figure 2. By reason of this construction various driving mechanisms hereinafter referred to may be lined up to perform their functionwithout undue friction, andonce the desired position of the head-stock 30 is. achieved it may be bolted in place by means of holding bolts 33.

Still referring to Figure l, the center 2| is, as in lathe practice, removably positioned in a workspindle 34, to the outer end of which is secured a driving plate 35. [The spindle 34 is suitably J'ournaled for rotation in the head-stock 30 and is rotated as will hereinafter be described.

' The majority of modern automobile crankshafts have integrally forged' therewith at one end a driving plate 36, to be secured ultimately to the automobile flywheel, and this driving plate 36 has one or more holes therein and usually one hole at least is located to precision limits a fixed radial distance from the crankshaft center, and I find such crankshafts may readily be driven by locating a driving pin 31 removab secured to the driving plate 35 in such hole in the driving plate 36, but for other types of crankshafts, or for this type if desired, the usual lathe dog may be employed. a Assuming now that the spindle 34 is rotated, the table I2 and the head-stock 30 having been fixed in position and the centers 2| and 22 engaging the crankshaft 20, and the driving pin 31 fixed in position as described, with the locking device 25 in locking position, the crankshaft 20 will be rotated, and successive crank-throws 4|, 42, 43 and 44 will partake of circular orbital movements, with diurnal motion equal in angular velocity to the angular velocity of their orbital motion respectively. I have illustrated herein a crankshaft with successive throws angularly dis- I placed 90 deg. from the preceding throw in the orbital path, but the much used four-throwcrankshaft with all throws in a plane, may be ground on the present machine, and so also may any type of sixor twelve-cylinder crankshaft, such as the familiar type of crankshaft employing the one hundred and twenty degree angle of displacement.

For the grinding of the crankshaft 20 or any other work-piece according to the present invention, I provide a plurality of grinding wheels 5|, 52, 53 and 54 (see now Figure 6) which I cause to rotate diumally and also to move orbitally in a circular motion complementary to that of the several throws 4|, 42, 43 and 44, that is with the orbital movement of each grinding wheel always in phase with the orbital movement of the throw it is grinding, and having the same radius and angular velocity. I further provide means colleca tively to displace all the orbits of the grinding wheels towards the orbits of the crank-throws to produce a cutting in-feed.

Still referring to Figure 6, I provide an electric motor 60 to which is coupled ashaft 6| by means of a coupling 62, the shaft 6| being mounted in suitable bearings 63 and-64, and the shaft 6I having affixed to it four pulleys I I, 12, I3 and I4 which are connected by belts I5, 16, TI and "to pulleys 8|, 82, 83 and 84 attached to the several grinding wheels 5|, 52, 53 and 54. Likewise mounted on the shaft 6|, but not fastened thereto. are arms 85, 86, 81 and 88 which mount idler pulleys SI, 92, 83 and 84 that serve to tension the Figure .8)

. 2,012,263 'rests upon the same ways I3 and I4 that the belts 15, I6, I1 and I8, springs 95, 86, 91 and 98 providing the required tefision.

Referring now to Figure 5, I provide for the machine a number of crankshafts I 00, each one of which is the counterpart of a crankshaft to be ground, so far as angular position of crank throws or pins and radius of throw thereof and longitudinal spacing of throws arev concerned. Each crankshaft I00 is-preferably an' integral forging, and has pins IOI, I02, I03 and I04 upon which are mounted the pulleys 8|, 82, 83 and 84 respectively, these pulleys being each split pulleys, that is formed of a pair of similar halves for assembly purposes (this type of construction being illustrated with respect to themodification, in Pulleys 8|, 82, 83 and 84 fit nicely between shoulders II 0 and III on the respective .throws IOI --I04, and these pulleys constitute mountings for the respective grinding wheels 5I54, which are thereby freely rotatable on the several pins IOI| 04. The mounting for each wheel includes likewise an additional removable split clamping plate II2, each one secured to its corresponding combined pulley and mounting 8I84 by means of bolts I|3,'and when it is desired to replace a worn grinding wheel with a new one, the two halves of the plate II2 are first removed, whereupon the grinding wheel may be moved sideways off the shoulder on itspulley mounting, which frees the latter, the grinding wheels having holes therein sufficiently large to pass over the throws of the crankshaft I00.

' Referring now to Figure 2, I provide a crossslide or table I20 such as has been heretofore provided in grinding machines, and mounted on ways, not shown, provided therein; and on the base I I for movement perpendicular to the movement of the carriage I2 on ways I3 and I4. It is by movement of the cross-slide. I20 that the cutting action is secured, and the cutting feed which may be, continuous, if desired, is achieved in any usual or desired manner, such as by means of a cross-feed screw I2| mounted, integrally formed on, or securedto a shaft I22, which is mounted in suitable journals or bearings not shown,provided in the machine base II, and which is actuated by means of a hand wheel I23 (see also Figure 1) and associated mech- 'anism including interposed gearing and shields,

stop devices I24 and the like, all ofwhich may be of any usual or desired form, for example such as shownin U. S. Letters Patent No. 762,838'granted to Charles H. Norton. By such a mechanism a graduated and controlled,

' and if desired a continuous cross-feed of the cross-slide I20 may be secured, and such move- 'ment is a precision one, and relatively speaking a slow one or'one composed of ,minute successive increments. As shown in Figure 2, the motor 60is 'mounted'oncross-slide I20; likewise mounted thereon are the bearings 63 and 64 of the shaft 6|. Each crank I 00 provided for the machine, in addition to the two, four, six or any other number of crank-throws orpins provided, has a. pair of end trunnions I25 and I26.v

Referring to Figure 2, to the trunnion I25 is attached a worm wheel I28. The trunnion I25 is removably mounted in a journal I30 which is a two-part journal for removal of the crankshaft |00; the other trunnion 26 is removably mounted in a two-part journal I3I. The bottom half of each of the.journals I30 and I3I is fastened'to the cross-slide I20, 8. fixed distance from the axis of the shaft 6|, although, adjustably .on the axis of the crankshaft I00.

Thus all of the grinding wheels and the dIiVr' ing mechanism therefor are carried on the crossslide I20 so that they may be caused to approach and recede from the work-piece collectively at will.

Referring now to Figures 2 and 6, I provide mechanism for rotating the work-piece crankshaft 20 and the grinding 'wheel supporting crankshaft I synchronously, that is at the same angular velocity, and I further provide means for synchronizing their phases. The work-spindle 34 has rigidly secured to it a worm wheel I35, and with this worm wheel meshes a worm I36 which is afiixed to a shaft I31 that is journaled in a bearing, not shown, in the work-head 30. The shaft I31 extends through a pair of bearings I38 carried by a standard -I39 projecting upwardly from the cross-slide I20, and the shaft I31 likewise passes through a couple of bearings I40 carried by a casing I4I also secured tothe cross-slide I20, which casing I4I likewise supports a bearing I42 for a shaft I43 that is in line with and adapted to be coupled to the shaft 6|, by means of a clutch to be described. Meshing with the worm wheel I28 is a worm I44 which is held in a fixed position so far as translation is concerned with respect to the cross-slide I20 by the bearings I36.

The worm I44 is splined and a long key I45 on the shaft I31, or any similar device to transmit angular motion without transmitting rectilinear motion, causes the shaft I31 to drive the worm I44 and therefore the worm wheel I28.

The casing I4I contains a large worm wheel (not shown) which is restrained from movement relative to the casing by the bearings I40, I40, the shaft I31 having a'long key I46 cooperating with a spline in said worm wheel, the purpose of this construction for transmitting power being the same as with respect to the worm I44. Fastened to the shaft I43 is a worm, not shown, which meshes with the aforesaid worm wheel to drive ,7

the same. The shaft I43 is normally connected by a positive dog clutch I 41 to the shaft 6I, but may be disconnected therefrom by means of a lever I48 having a pin I49 fitting in a groove I50 formed in movable part II of the clutch I41.

The movable part I5'I is splined to the shaft 6| while the abutting part I52 of the clutch I41 is fixed to its shaft I43.

When the clutch I41 is engaged and the motor 60 is running, power is transmitted along" the shaft 6 I through the clutch I41, and to the shaft I31,'thus to drive both cranks 20 and I00, and as the worms I36 and --I44 are of the same size and pitch, and likewise the worm wheels I35 and I28 are of the same size and pitch, the crankshafts are rotated at the same angular velocity, and since the worm wheels are so located on their respective shafts as to maintain corresponding crank-throws in the same phase relationship, and the two cranks are similar as heretofore pointed out, and their throws have the same radius, it follows that the orbital movement of each grinding wheel traces a circle similar to the orbital movement of each throw of the crank 20 and in the same phase relationship. By reason of the gear ratio which will be sufiiciently apparent from the accompanying drawings, the diurnal motion of each grinding wheel is very much greater than its orbital velocity, and further by reason of the large diameter of the grinding wheels as compared with diameter of crank-throws to be ground, a high peripheral grinding speed is achieved. Assuming a constant diurnal velocity of the grinding wheels and aconstant angular to .the work surface. By reason of the orbital motion, however, there is a tendency to change the velocity of each grinding wheel as the grinding wheel pulleys 0|, 82, 83 and 84 approach and recede from the driving pulleys 1|, 12, 13 and 14.

By using a non-positive drive for the wheels-5|,

52, 53 and 54 I find that their inertia of rotation checks this tendency, at least sufiiciently so that no harmful effects result.

A crank I00 having been chosen which has throws the same as those of acrankshaft to be ground, as stated, and grinding wheels having been mounted on such crank I00 as shown and described, the work-piece crank 20 is mounted in place between the centers 2|, 22 and the driving pin 31 is inserted in the hole in the plate 36. As-' suming that the center 2I is of a length to dispose several throws"4 I 42, 43 and 44 opposite the grinding wheels, the work-piece crank 20 may then be ground to finished size by starting the motor. 60 and then advancing the cross-slide I20 by turning the hand wheel I23. On account of the fact that the orbital movement of the grinding wheels is the same as that of the crank-throws to be ground, the planes of tangency between the sev-' ccsfively by all portions of the respective throws on account of their diurnal motion. Thus by advancing the grinding wheels to contact with the several throws, all of them may be ground by an equal amount and to' a given diameter. If desired, a continuous in-feed of the grinding wheels may be employed, in connection with a dwell at the end of such feed to continue the grindinguntil the effect of pressure in the several machine parts is removed. This is called grinding out the spar ployed, if desired. In order to avoid, as much as possible, grinding lines in the work-piece, the grinding wheels should be of-an even texture and have a relatively hard surface.

After the machine is once set up, similar cranks An intermittent feed may also be em- 1 may be introduced into the machine merely by limits, they should be trued. I provide truing mechanism to true the wheels 5I 54 without removing them from themachine.

Referring now to Figures 1 and 4, a truing hold er I60 has therein a rod I6I having screw threads, not shown, cooperating with internal threads in the holder I60. The rod I6I has'a diamond I62 in one end thereof, and on the other end a knob I63 by the angular adjustment of which the position of the diamond I62may be adjusted to within precision limits. The holder I60 has ways I64 fitting ways I65 providedonthe table I2.' An integralbracket I66 carries a pinion gear I61 cooperating with a rack I68 afiixed to the table I2 as shown in Figures 1 and 4 which serves as an adjusting means for, positioning the holder relative to the table I2. Referring to Figure 1, the holder I60 is held in adjusted position on the table 82 by means of a binder bolt I10, andby tightening this bolt the holder I 69 may be rigidly secured to the table I2. Prior to such rigid clamping of the parts together, however, the diamond I62 may be adjusted to exactly the desiredposition relative to the table I2 in a longitudinal direction by turning the bolt-headed stud I'll upon which the pinion I61 is mounted.

. In connection with the truing of the wheels, I provide means to restrain the orbital movement thereof while permitting their diurnal motion. Referring to Figure 1, an index plate I15 is secured to the end of crankshaft I00, this index plate H15 having a number of indexnotches I16 equal to the number of throws of the crank to be ground and positioned angularly on said index plate by angles corresponding to the displacement of the several throws. When it is desired to true the grinding wheels and to insure the grinding of.each throw 4 I, 42, 43 and 44 to the same diameter, clutch I 41 is first released, and then the shaft 19 is turned (by manually turning the shaft I43, for example) until one of the notches is engaged by a detent I11 mounted, as shown in Figures 2 and 3, in a portion of the bracket I39. This restrains orbital movement of the grinding wheels, and one or more of them are in a forward position. The dressing holder I 60 having been secured in position as described, the motor 69 may be started, and then by turning the hand wheel 55, the diamond I62 may be traversed with whatever wheel is at that time farthest forward. It is noted that the crank -20 will preferably not be located in the machine at this time, and it is further observed 'that coarse longitudinal adjustments of. the diamond holder maybe made by positioning it in the desired place on the table I2, while the traversing action of the diamond is better achieved by moving the table afterthe dressing device is locked in position. To insure contact between wheel and-diamond, screw I63 may be turned.

Having trued one -of the four (more or less) wheels, the detent I11 is withdrawn as by, pulling the action of a spring I80, and the shaft I rotated until the next notch I16 comes under the e e the notch and it is noted that the detent is preferablyof wedgeshape, as shown, to coopere gate with the wedge-shaped notch to determine accurately the position of the several grinding wheels in their orbits.

A second wheel having been positioned forward, it is now trued-by traversing the table I2 through the medium of the hand wheel I 5. In some cases this may be done without readjusting the bracket I60 on the table I2, and in other cases such' readjustment will be effected, but the position of the diamond I 62 with respect to the cylinder containing all of the orbits should remain the same, which will be the case if the adjustment of the knob IE3 is undisturbed.

If the several wheels are successively trued as indicated, both by reason of the fact that their orbits all lie in the same cylinder, and by reason further of the fact that the table I2 moves in a line parallel tothe axis of thatrcylinder, and wherefore parallel to all of the elements thereof, the several grinding wheels will be dressed and trued to the same diameter which, under the conditions and with the machine as described; will insure, in succeeding grinding actions, the production of ground crank-throws all of the same diameter.

Subsequent to the truing operationsthe detent I11 should be withdrawn by pulling out the knob I19, and the detent may be held in withdrawn position by giving the knob I19 a partial turn. The knob I19 and the detent I 11 are connected by a shaft I8I projecting laterally from which is a pin I82 slidably in'a slot I83. Pin I82 and slot 483 serve to align the detent I11 in its operative position, and upon withdrawal of the detent the pin I 82 moves out of the slot I83 and after the parts are given a partial turn the pin I82 engages the front face of a bearing portion I84 thus to Hold the detent withdrawn. The machine is then ready for the introduction of a crankshaft 20 to be ground, and orbital movement of the crankshafts 20 and I00 is resumed upon engagement of the clutch I41.

Figures 7 and 8 illustrate a modification in the wheel mounting mechanism. A wheel mounting crankshaft IIlIla. is provided whose throws or pins represented by pins Ill2a, I031: and Ma have threaded portions I 02b, I03!) and Nb upon which are mounted spanner nuts I99 engaging washers l9I which engage the pulley mountings 8 I, 82, 83 I and 84 respectively, the other side of said pulley wheel mountings being engaged by washers I92 that are backed up by springs I93 located in the crank-arms as shown in Figures 7 and 8. By turning the spanner nuts I90 one way or the other the longitudinal position of each wheel maybe adjusted sufliciently to cause each wheel to be cated accurately with respect to the fillets on the crank-throws 4|, 42, 43 and 44 which were produced in the previous operation, either a lathe operation or a forging operation or otherwise.

One adjustment laterally of all the grinding wheels 5|, 52, 53 and 54 will probably suflice for the grinding of any given lot of crankshafts in actual production practice. It should be noted that-this means of adjusting the position of the several grinding wheels permits the wheels to split the spar on all throws thus achieving economy so far as wear of the grinding wheels is concerned. a knob I19 thus withdrawing said detent against It will thus be seen that there has been provided by this invention with many thoroughly practical advantages, are successfully achieved.

As various 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.

1. A grinding machine comprising, in combination, a crankshaft with a plurality of throws, a plurality of grinding wheels one on each of several of said throws, a rotatable mounting for a work-piece, means to rotate the said mounting, means synchronized with said last-named means to rotate said crankshaft, and flexible means to rotate each of said grinding wheels.

2. A grinding machine comprising, in combination, a plurality of grinding wheels, individual mounting means for each of said grinding wheels movable through predetermined paths, a rotatable mounting for a work-piece, means to rotate said last-named mounting, means to rotate each of said individual mountings for said wheels through their predetermined paths and synchronously with said mounting for said work-piece. and

an apparatus in which the various objects hereinabove set f rth, to th detent I11. The spring I89 causes the detent to o ge er ing wheel,

means to rotate each of said wheels on its mount- 3. A grinding machine comprising, in combination, agrinding wheel, means to rotate orbitally said grinding wheel, means to rotate diurnally said grinding wheel, means to rotate a work-piece on an axis entirely outside the orbit of said grindand means to cause said work-piece to approach said orbit by grinding increments.

4. A grinding machine comprising, in tion, a plurality of grinding wheels, a, mounting for each grinding wheel, means to move the axis of each grinding wheel through predetermined courses at equal angular velocities, means to rotate each grinding wheel on its axis, means to arrest any grinding wheel at a. predetermined angular position in its course which is the same for all said wheels, means to locate a dressing device at such position, and means to traverse said wheel with'said dressing device.

5. A grinding machine comprising, in combination, a grinding wheel, means to rotate said grinding wheel orbitally, means to rotate said grinding wheel diurnally at a velocity greatly-in excess of the velocity of its orbital motion, means to rotate a work-piece orbitally, and means to rotate said work-piece diurnally at the same angular velocity as the orbital motion.

6. A grinding machine comprising, in combina-.

tion, a plurality of grinding wheels means to rotate all of said grinding-wheels in the same orbital path maintaining their ascensions different and their relative hour angles the same, and

means to rotate each wheel diurnallyat substantially a constant angular velocity.

'7. In a grinding machine as claimed in claim 6, the combination with the parts thereinspecified, of precision means to true each wheel to the same diameter.

8. In' a grinding machine as claimed in claim 6, the combination with the parts therein specified, of means for arresting any of the said grinding wheels at a given and at the same hour angle combinawhile maintaining its diurnal motion, a dressing device, means to traverse said dressing device relative to the grinding wheel and in a line perpendicular to the plane of any orbit, and means to adjust the position of said dressing device.

9. In a grinding machine, a drive shaft, a plurality of pulleys on said drive shaft, a pair of separated journals in a line parallel to said shaft, a member having a plurality of in said 'ournals for rotation, a grinding wheel mounted ior rotation on each pin, a pulley aflixed to each grinding wheel, each of said first-named pulleys being in line with a. pulley for a grinding wheel, flexible driving means connecting the several sets of pulleys, and means driven from said shaft for rotating said member.

10. In a grinding machine as claimed in claim 9, the combination with the parts therein specifled, of a work-piece spindle parallel to said journals, and means to drive said spindle at the same angular velocity as and in the same phase relation as said member.

11. In a, grinding machine 9, the combination with the parts thereinspecified, of a work-piece spindle parallel to said journals, means to drive said spindle at the same angular velocity and in the same phase relation as said member, a dressing device, a mounting for said dressing device to move it parallel to the axis of said journals, and means to arrest said shaft at any one of a plurality of positions.

12. A mounting for a plurality of grinding wheels comprising a, pair of trunnions mounted in line, a plurality of pairs of crank-arms, a plurality of pins each pin detachably mounted between a pair of crank-arms, and a plurality of wheel mounting members each journaled on a pin. F

13. In a mounting as claimed in claim 12, the combination with the parts therein specified, of means for adjusting axially on its pin -one or more .wheel mounting members.

CHARLES H. AMIDON.

axis pins mounted as claimed in claim

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