US3022680A - Incremental feed mechanism - Google Patents

Description

Feb. 27, 1962 J. VAN ROOJEN 3,022,680

INCREMENTAL FEED MECHANISM 2 Sheets-Sheet 2 3,022,686 Patented Feb. 27, 1962 thee 3,022,680 v EWCREMENTAL FEED MECHANISM Jan van Robien, Rockford, i., assigner to The Ingersoll Milling Machine Co., Rockford, Ill., a corporation of Illinois Filed July 1S, 1960, Ser. No. 43,432 2 Claims. (Cl. 74-625) This invention relates generally to a mechanism for converting the reciprocatory motion of a power actuator into a unidirectional motion of a driven part to advance the latter in successive steps of equal lengths while providing for independent manual adjustment of the driven part to establish a selected starting point for the step-by-step movement. More particularly, the driven part is indexed or advanced step-by-step by a means comprising a one-way clutch of the instantly engaging type and its positions are retained by a similar unit acting as a brake during the retracting strokes of the actuator.

The general object is to provide a mechanism of the above character which, as compared to prior devices, is simpler and more economical in construction and capable of being indexed in a greater number of steps.

A more specific object is to take advantage of an inherent but seldom used characteristic of the instantly engageable clutches and brakes to permit manual disengagement of the power feed, independent manual movement of the driven part, and re-engagement of the feed with virtually no movement of the driven part during uncoupling and recoupling.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which- -FiGURE l is a fragmentary side elevational view of a cutter sharpener incorporating an incremental feed mechanism embodying the novel features of the present invention.

FIG. 2 is a fragmentary vertical section of the reciprocating actuator.

FlG. 3 is a fragrnnetary section taken along the line 3 3 of FG. l.

FIG. 4 is a somewhat enlarged fragmentary section taken along the line 4-4 of FIG. y3 showing another position of the driven shaft.

FlGS. 5 and 6 are fragmentary sections taken respectively along the lines 5-5 and 6 6 of FIG. 3.

For purposes of illustration, the invention is shown in the drawings embodied in a grinding machine in which a power rotated abrasive wheel is reciprocated in a generally horizontal path back and forth across a dressing point 11 and the work surface to be ground, in this case the edge 12 of a blade 13 on a cutter 14. Contouring of the Wheel 10 by the dressing point and following the contour of the blade edge are controlled by a cam 15 on the Wheel head 16 riding along a stationary follower 17.

The cutter 14 is held in a fixture 18 including a support 19 and a carrier 20 and is indexable relative to the fixture to position successive cutter blades for the grinding operation. Slidably mounting the carrier 20 on the machine base 21 for vertical step-by-step movement are guide barsV 22 xed at their upper ends to the machine base and at their lower ends to a bracket 23 on the base. A screw 24 (FIG` 3) fixed to and upstanding from the bracket threads through a nut 25 forming the hub of a bevel gear 26. The nut is journaled in a thrust bearing 31 in the carrier 20. The gear meshes with a bevel gear 27 on a sleeve 27a journaled in bearings 27b and internally Splined to receive mating spline teeth on the end of a horizontal shaft 28. The latter is journaled in bearings 29 in the carrier 20. Turning the shaft in opposite directions rotates the nut thereby raising and lowering the carrier 20 along the guide bars and the screw.

Intermittent turning of the shaft 28 to feed the carrier upwardly step by step is etfected by a reciprocating actuator mounted in a housing 49 and comprising a cylinder 3'4 and a piston 33 slidable back and forth therein in response to the admission of pressure alternately into opposite ends of the cylinder. The outer end of the piston rod 36 carries a rack 35 guided in bearings 39 in the carrier 2t) and meshed with a mutilated pinion 37. Formed between the inner wall of the carrier and a retaining end plate 53 encircling the shaft 28 is a groove 32 in which the pinion is journaled loosely around its outer periphery and located axially between the inner side wall of the groove and the plate.

The piston 33 and rack bar 35 reciprocate back and forth between stops, one provided by the head end of the cylinder 34. The other stop is a screw 41 threaded into the actuator housing and adjustable by a micrometer 42 to determine the length of the forward stroke of the rack.

The means herein shown for coupling the pinion 37 to the shaft 28 during the forward strokes of the rack comprises a one-way driving clutch 38 ofthe Morse so-called Series 200type. Clt includes a cylindrical outer race 43 (FIG. 6) formed by the inner periphery of a ring'4'4 concentric with and telescoped in the bore of `the pinion 37 and held rigidly therewith by a key 45. The cylindrical inner race 46 of the clutch is formed directly on the shaft 2S concentric with the axis thereof. Eccentriccams or wedges `47 for gripping the races are arranged in an annular series between the latter and are positioned axially between two retaining rings 48 pressed into counter-bores at opposite ends of the ring 44. Garter springs 49 seated in notches '51 in the ends of the wedges hold the wedges against the outer race 43. The wedges are tiltable, rol-lerlike elements having an arcuate rolling surface 54 bearing on the inner race 46 and an eccentrically disposed outer edge 55 engageable with the outer race. The effective thickness is greater than the spacing o-f the inner and outer races so that upon turning of the outer rin-g in vvone direction, clockwise as shown in FIG. 6, the wedges are rocked to press their inner arcuate surfaces into gripping engagement with the inner race and thereby immediately lock the two rings `together for turning in unison during the entire stroke ofthe rack bar. Atv .the beginning of the return stroke, the wedges are rocked reversely releasing the gripping pressure so as to free lthe outer race for turning independently of the shaft 28.` p p A similar but reversely acting unit 56 (FIG. 5) is spaced axially along the shaft 28 from the driving coupling 38 and operates as a feed b ackstop brake effective to grip the shaft and prevent counter-rotation thereof during return strokes of the piston 33 while releasing the shaft during the forward strokes. In this unit, the outer race ring 44' is seated in a groove 32 formed between the inner carrier wall 52 and a retaining end plate `61 and is' secured to the carrier 20 by a key 45'. As before, the inner race 45 is formed directly on the sha-ft concentric with the axis thereof. Since the outer race is fixed, however, the brake is disengaged during rotation of the shaft by the driving clutch 3S, engages to prevent reverse turning during the return stroke of the piston, and disengages when the next forward stroke begins.

Clutches and brakes of the character above described may be said to be instantly engageable. That'is to say, the surfaces of the wedge elements of the driving clutch grip the inner and outer races instantly, with virtually no loss of motion, upon turning of the outer race ring thercollar 66. Both ;engagement of the inner races and the Wedges.

The invention contemplates utilizing this unique characteristic of instantly engageable one-way clutches and brakes to enable the clutch 38 and brake 56 to be disengagedY simultaneously simply by' axially shifting the driven shaft 28 to carry the two inner races out of association with their respective wedge elements. This permits the shaft to be turnedindependently of the power actuator for lmanual movement of the actuated device or cutter mounting to adjust the same to a new desired position. Similarly, by reverse shifting of the shaft, the inner Vraces are brought Iback into the planes of their wedges,

thus reconditioning the clutch and the brake for ratcheting of the shaft by the power actuator.

During automatic operation, the -shaft is held fby a helical spring 57 against axial movement out of the position wherein the inner races are disposed in the planes of the respective wedge elements, as shown in FIG. 3. The spring is seated in the countenbore 58 around the splined bore 59 and acts in compression against an annular shoulder 69 rigid with and encircling the shaft 28, and 'bearing against the end plate `61.

To permit disabling of the clutch and the brake by axial shifting of the shaft, surfaces 62 on the shaft 28 adjacent the races 46, '46 are of slightly reduced diameter, in this instance about .056 of an inch smaller than theraces. This is shown on an exaggerated scale in FIG. 4. When the shaft is shifted to the left out of the driving position shown in FIG. 3 into the disengaged position shown in FIG.V 4.,.the`reduced diameter surfaces become disposed in the planes of the respective wedges, 'and both the clutch and the brake are disabled. The extent of the shifting is somewhat greater than the axial length of the inner races so that the latter are carried completely out of engagement with the wedges, such shifting being permitted by compression of the spring 57` The inner races and the surfaces 62 of reduced diameter are spaced a short distance apart axially and joined by frusto-conical surfaces -63 which serve as guides to facilitate 1re-entry of the races into proper relation with the Wedge elementsras Vthe shaft 28 is shifted reversely to effect rc2-engagementV of the races and the wedge elements. Y

Back and forth shifting of the shaft and turning thereof While the clutch 38 (.FIG. 4) may be accomplished conveniently by a `hand wheel Y64 fixed to theoutwardly projecting end of the shaft and having a hub 65 which is adapted for abutment with a collar 66 to limit the inward shifting and thereby locate VVthe races 46, 46 out of the planes of the respective wedges. The collar is split and adapted to grip the shaft 28 upon manual actuation of a suitable screw clamp 70. It is journaled in a ring 67 xed to the outer end-of the retaining plate 53.

When it is desired to change the' position of the cutter mounting independently of the power actuator, the operator grasps the wheel 64and pushes it inwardly against the action of the spring 57 until the hub 65 comes against the clutch and the brake are thus dls'engaged and the position of the shaft may be retained by tightening the clamp 70. Then, by turning the hand andthe brake 56 are disengagedV scenes@ with Y 4 wheel, the'cutter mounting maybe lowered `for the purpose of changing cutters and again raised to a desired position.

It will be apparent that the power actuator or the manual adjuster may be conditioned selectively for individual operation simply byrback and forth shifting of the shaft 28 which is a common element of both drives. Moreover, the structure required for such changes is exceedingly simple involving as it does only the mounting of the shaft for axial shifting and the formation of the reduced diameter surfaces thereon.

I claim as my invention:

l. The combination of a shaft, means supporting said shaft for turning about a fixed axis and also for axial sliding, an actuating member reciprocable back and forth through forward and return strokes, means for converting the successive forward strokes of said member into unidirectional step-by-step turning of saidV shaft cornprising an instantly engageable one-way clutch encircling the shaft and comprising an annular series of cams and concentric inner and outer races between which said cams become wedged upon relative turning of the races in one direction, said inner race being cylindrical and rigid with the shaft and concentric with said axis, a similar instantly engageable unit forming a brake for holding said shaft against reverse turning during and after the return strokes of said member and having a cylindrical inner race rigid with said shaft and spaced axially from said first race, the surfaces of said shaft adjacentsaid inner races being smaller in diameter than the races, and manually operable means for shifting said shaft back and forth axiaily between two predetermined positions in one of which both of said races Vare located for gripping engagement with the respective cams, said reduced diameter surfaces on said shaft being disposed in the planes of the respective cams in the other of said positions whereby to disable the clutch and the brake and permit turning of said shaft independently of said reciprocable member. 2. The combination of a shaft, means supporting said shaft for turning about a iixed'axis and also for axial sliding, an actuating member reciprocable back and forth through forwardY and return strokes, means for converting the successive forward strokes of said member into unidirectional step-by-step turning of said Vshaft comprising an instantly engageable one-way clutch encircling the shaft and comprising an annular series of cams and concentric inner and outer races between which said cams become wedgedv upon relative turning of the races in one direction, said inner race being cylindrical and rigid with the shaft and concentric im'th said axis, a similar instantly engageable unit forming a brake for holding said shaft against reverse turning ,during the returnstrokes of said member and havingia cylindrical 'inner race rigid said shaft and spaced axially from said rst race, the surfaces of said shaft adjacent said inner races being smaller in diameter than the races, and manually operable means for shifting said shaft back and forth axially to carry both of said inner races into and out of location for gripping engagement with ysaid cams and thereby respectively engage and disengage both said clutch and said brake, said shaft having frustro-conical surfaces between the inner races and said smaller diameter surfaces to facilitate re-entry of the inner races into engagement with said cams. Y

-References Cited in the tile of this patent I

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