US1465068A - Uniformly-driven cam-grinding apparatus - Google Patents

Description

Aug. M, 1923. 3.4-65068 A, TURNER UNIFORML-Y DRIVEN CAM GRINDING APPARATUS m Filed sept. 2a, 1918 2 sheets-Sheet 1 @B, m

.y l g3 m l 1| /jsiLl-f w w1 H5335 a@ l| n n m (u o1 Il l() u @kb l -f FIT 9 ummml QQ I, 35% kw @QS s l L\ p m /I .L"\)

Hr a e@ #xo 3 .5. *w y g Q W I :wr i :fzgl

Il.Il f E "`\\\Q Q l L w 1 gg N w W L\ S" um WN I w 1 o M vf l m @i I N um n) n i3 QQ f w3 Il \\1 :I '"3 n ""lb A l -I fm u Nil A w QNL I k' 'g i H Q r Q M1" f-v`; vif

i i #U ily@ INVENTOR 05 /em Tanya? Aug. 14, 1923. l 1,465,068 `A. TURNER UNIFORMLYv DRIVEN CAM GRINDING APPARATUS Filed sept. 22 1918 2 sheets-sheet 2 INVENTOR ORNEY the work are rotated by Pamesa aug. te, was.

NITE@ STATES meente rarest creates.

ALBERT TURNER, 0F WORCESTER, MASSACHUSETTS, ASSIGNOR TO NORTON COMPANY, 0F WORCESTER, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

UNIFORMLY-DRIVEN CAM-GRINDING APPARATUS.

Application filed. September 28, 1918. Serial No. 256,082.

To all whom it may concern.'

Be it known that I, ALBERT TURNER, a citizen of the United States of America residing at Worcester, in the county of Worcester and State of Massachusetts, have invented certain new and useful Improvements in Uniformly-Driven Cam-Grinding Apparatus, of which the following is a full, clear, and exact specification.

This invention relates to machines for grinding bodies having non-circular perimeters and more particularly to a mechanism for uniformly rotating the work in a cam grinding apparatus.

In the art of grinding cams, the devices generally used involve a swinging frame which supports the work to be ground against a grinding wheel and is rocked back and forth by means of a master cam rotatably mounted on the frame in contact with a cam follower fixed on the grinding machine.

In such constructions the master cam and a gear or belt connection with a shaft fixed relative to the swinging frame pivots., Because of this type olf driving connection, the work is not rotated with a uniform angular velocity, but is retarded or accelerated, depending upon the direction of rotation, when the frame swings to permit the wheel to grind the rise or the drop on the cam. This variation in grinding results in chatter marks and a departure from the true pattern to beground, and so is highly objectionable.

It is accordingly an object of 'my invention to provide a grinding apparatus for cams or other curved objects having noncircular perimeters, in which the relative angular velocities of the work is maintained substantially uniform, while the work and wheel are reciprocated relative to each other ,to permit grinding the work surface as the point of contact varies in radial distance from the work center.

With this and other objects in view as will be apparentfrom the followiwng disclosure, my invention resides in the combi.

nation of parts set forth in the specification and covered by the claimsl appendedhereto. In the drawings in which like reference numerals indicate like parts:

Fig. 1 is a front elevation partlybroken awaj,1 of a swinging frame embodying my ingention as attached to a grinding machine ta e;

Fig. 2 is -a section on the line 2 2 of Fig. 1; v

Fig. 3 is a right-hand elevation of the machine shown in Fig. l; and

Fig. 4 is a detail plan view of the drivinO' mechanism.

illy invention contemplates the provision of a grinding apparatus involving a rotatable grinding wheel and a Work support adapted to present work to be ground continuously to the grinding surface of the wheel. The Wheel and the work are moved relative to each other in a path transverse to the work axis, in accordance with the variation in the radial distance of the work center from the surface of contact with` the grinding wheel, and means are provided for imparting a uniform angular motion to the movable rotating bod during this transverse movement. Whi e it is immaterial So far as this invention is concerned, whether the grinding wheel or the work itself reciprocates in such transverse motion, I prefer to mount the grinding wheel on a fixed base and reciprocate the work relative thereto. This reciprocating motion may be effected as illustrated by mounting the work on a swinging frame and automatically rocking the frame by means of a rotating pattern engaging a shoe, one being mounted on the frame and the other on the base which supports the swinging frame. To rotate the work at auniform angular velocity, I preferably make use of a flexible work-driving connection between the work and the master cam shaft, and a fixed driving shaft.

In order that the invention may be more fully understood, reference is had to the drawings illustrating one embodiment thereof in which I have shown the usual form of slidable table 1 mounted on the grinding machine base and carrying a swivel table 2 on which is mounted the swinging frame base 3. The work may bel reciprocated by means of a swinging frame comprising vertical standards 4, 5 and 6 connected together by top `and bottom cross pieces 7 and 8 which is supported by the upright arms 9, 10 and 11 on the base. The frame is mounted' on pins 12, 13 and 14 which are carried by the vertical arms 9, 10 and ico 11. A casing is also supported by the two upright arms 10 and 11 and is adapted to carry the master cam follower and its operating mechanism, presently to be described.

The work to be ground, illustrated in the drawings as a cam shaft, is supported by suitable means on the lower portion of the frame. This support may comprise a footstock 16 having an adjustable centering pin 17 mounted therein for supporting one end of the work.,v The other end is supported by the centering pin 18 which is mounted in suitable bearings in the .vertical standard 5 of the swinging frame. The work may be rotated by suitable mechanism such as a lug 19 on the pin 18 engaging a driving dog 20 clamped to the work, as by means of a set screw.

In the present embodiment, I have illustrated the master cam shaft as being mounted on the frame and axially aligned with the work. This cam shaft 22 may be integral with or rigidly connected to the centering pin 18 of the work in order that the work and the pattern may rotate synchronously and simultaneously. The outer end of this cam shaft is mounted in suitable bearings in the standard 6. Master cams 23 are removably located on this shaft. indesired spaced relation and are adapted to rotate against a master cam follower which is mounted 1n the casing 15 on the fixed base. This follower may be a roller 24 mounted on a spindle 25 carried by suitable bearings 26 in the fixed casing 15, this roller being adapted to be rotated by frictional contact with the master cam, in order that a new surface may be constantly presented to the cam and thereby obviate any error due to wear on the roller.

In order that the roller 24 may be adjusted to a position opposite any one ofthe master cams, it is mounted loosely on the shaft 25 and adapted to be moved along the same by suitable means. In the embodiment illustrated, this may comprise a yoke 27 straddlin the roller 24, which is moved longitudina ly by a screw-threaded shaft 28 mounted in bearings` 29 in the walls of the casing 15 and cooperating with threads in the yoke.

. This shaft 28 is rotated by a bevel gear 30 thereon, which 'meshes with another bevel gear 32 mounted on the shaft 33, which is rotated by a suitable hand-operated mechanism 34. The position of the master cam roller may be noted by means of a pointer 35 travellng over a scale 36, this pointer 35 being carried by a block 37 non-rotatably keyed to the casing 38 and threaded on the shaft 33, whereby rotation of the hand wheel l slides the block.

It is accordingly seen that in the construction so far described, when the master cam shaft 22 is rotated, the irregularly shaped master cams push against the master cam roller 24 which is mounted on fixed supports and so swing the frame and move the master cam shaft and the work which is axially.

aligned therewith in a transverse motion relative to their axes. These parts move in the arc of a circle about the center of the pivots 12, 13 and 14 of the frame. By this means the cam shaft 40 is reciprocated relative to the rinding wheel 41, herein diagrammatic'alIy shown, this grinding wheel being mounted on fixed supports on another part of the grinding mach-ine, whereby it may be rotated with uniformvelocity by suitable driving mechanism.

In order to insure uniform swinging motion of the frame and prevent the same jumping as the grinding wheel asses over a high point on the work, suita le mechanism may be provided to hold the work firmly against the rinding wheel. In the form illustrated, this comprises two spiral r 11 on the base by means of set screws 44, so

that a rise on the master cam forces the frame to swing about the fixed centers a ainst the reactive pull of the springs 42.

he tension of these springs may be adjusted by loosening the set screws 44 and rotating the pinswithin the bearingsto a desired position.

`Suitable mechanism may be provided also for taking up any back lash in the driving mechanism and to prevent the swinging frame from moving'irregularly. This may comprise 'a brake drum 46 keyed to the shaft 22 to rotate therewith. This drum is engaged by two brake members 47 which constitute a yoke clamping against the periphery of the drum, these members being hinged together at 48 and held together at their lower end by suitable clamping means 49, the pressure of these clamping means bein adjustable to give the desired tension.

ince in this type of grinding apparatus either the wheel or the work must move transversely relative to the axis of grinding, and in the present embodiment the work is reciprocated, it is necessaryA that a driving connection be made with this reciprocating work from a stationary source of power. To avoid variation in the angular velocity of the master cam shaft 22 and the driving spindle 18, I provide a flexible drivling connection between these movable parts and the recense swinging frame and is provided with arms 52 and 53 (Figs. 3 and ai) clamped to an enxtension 54e of the standard. rlhese arms carry a shaft 55 on which pulleys 56 are mounted, these pulleys. being adapted to be driven by any suitable outside source of energy. rlhe extension ft is a hollow, preferably conical member havingV bearing portions 57 and 58 therein. llctotatably mounted in these bearings is a conical member 59 having a projecting portion 60 provided with gear teeth thereon which mesh with the gear wheel 61 on the shaft 55..

While this driving mechanism' may obviously be of other` shape, l have made it of aconica'l shape in order to economas space and provide a compact mechanism for my `versal joint simi flexible driving connection. lt has a large central opening so that the teles'coping linkage therein may swing with the frame. plate 62 is fastened on the small outer end of the conical driving member 59. AThis plate is provided with projecting lugs 63 (Fig. 4) which ,carry a' ring 64 pivotally mounted thereon. Yihis ring 6e in turn has projecting pins mounted in lugs 65 on the member 66 of the driving mechanism. The member 66 has rigidly fixed thereto an inwardly projecting shaft 67 having a reduced portion 68 which telescopes within a hollowl shaft .69, and is keyed thereto lfor rotative movement with the hollow shaft while sliding longitudinali therein. A second'uniscribed is rovided 'to connect this hollow shaft 69 with the cam shaft 22. rlhis joint may com rise, as illustrated, the member il onthe ho low vshaft 69 having lugs 72 thereon which pivotally car a central ring 73 which in turn ispivotal y mounted on lugs 7 l of the end piece '75 affixed to the shaft 22. ln order to strengthen the frame and suport the brake drum and the shaft 22 adjacent the universal coupling, l provide an arm 7 6 depending from the upright member 6 of the frame, a. suitable bearing being provided in this arm for the sha 22.

lln order that the frame may be moved back from the grindin wheel for the insertion or removal of wor l provide any suitable mechanism com rising, for example, the hand lever pivota ly mounted on the fixed standard 10 of the grinding machine and having a rod 81 eccentrically pivoted thereto and pivotally connected with a further lever 82 which is pivotally mounted on the i pin 13. A pin 83 projecting from the joint between levers 81 and 62 engages the upright standard 5 of 'the frame and causes it to swing backwards when the handle 80' is moved.,

The operation of the device is obvious from the above disclosure. When it is desired to grind an irregular body'such as a cam on a camshaft, the work is properly ar to the one above de' 60, causing the universal joints and the telescoping members to rotate therewith. No matter, what position the frame assumes in swinging back and forth the flexible connection takes care of this movement and causesthe shaft` 22 to rotate at a substantially uniform angular motion with the member 60., rllhe work d0, being in align -ment with and rotating synchronously with the shaft 22, is also moved at the same angur lar velocity.

What l claim is l. lin a grinding machine a rotatable work support mounted to move ina path transverse to 'the work axis, a non-swinging r0- tatablel driving member substantially aligned with said work support, and means comprising enible connections between said member and support for imparting uniform angular motion to the work support during such transverse movement.

2. lin a grinding machine, a movable work support, means to move the same in a path transverse to the anis of the work, a work driving shaft mounted on the support, a rotatable driving shaftvmounted in a fixed poi sition in substantial alignment with the work driving shaft and flexible connections` between said shafts whereby the work may be rotated uniformly as the work support moves.

3. lin a grinding machine, a swinging frame, awork drive mounted thereonV to move in a" path transverse to the work airis as the frame swings, a master cam rotatably mounted on the frame, a fined follower in contact with the cam so that rotation of the master cam swings the frame, a fixed driv-s` ing shaft approximately aligned with the work drive and flexible means connecting said shaft and work drive to rotate the work at a uniform angular velocity as the frame swings.

ll. lin a grinding machine, a frame mounted to swing in a path transverse to the airis of the work, a workholding device and a pattern shaft mounted on the frame in axial alignment, a grinding wheel, a rotatable pattern on said shaft, a follower fixedly mounted on the machine in contact with the pattern so that the frame is caused to swing by rotation of the pattern, a fixed driving device and flexible means operated by said driving device to rotate the work and pat tern at a uniform angular rate.

5. ln a grinding machine, a rotatable lll) @t accenna workdrive mounted'to' move in a path transverse to the work axis, a fixed driving shaft in approximate alignment with the work axis and a flexible connection between said shaft and work drive to rotate the work at a uniform angular velocity during its transverse movement.

6. ln a machine for dgrinding work of non-circullar perimeter, a rotatable grinding whee a frame movable relative to the wheel in a path transverse to the lworlr axis, a rotatable work drivev mounted on the frame, a rotatable pattern movable therewith, a follower fixed on the machine in contact with the pattern whereby rotation of the'pattern moves the frame and work relative to the grinding wheel, aunitormly rotating driving shaft fixed on the machine and a flexible driving connection between said shaft and the worlr drive and pattern adapted to rotate the latter at a uniform angular velocity as the frame moves.

7. lin a grinding machine, a movable work support, means to move the same in a path transverse to the axis of the worlr, a work driving shalt mounted on the support, a rotatable driving" shaft mounted in a fixed position substantially parallel with the worlr driving shaft, a telescoping member between said shafts, and universal joints connecting the endsot'said member with said shafts whereby the work may be rotated uniformly as the work supportmoves. y

8. lin a machine for grinding work having a non-circular perimeter, a rotatable grinding wheel, a frame movable relative thereto, a work support and drive on the frame, automatically operated mechanism to move the trame transversely relative to the axis of the grinding wheel and the worlr axis in accordance with a pattern, a uniformly rotatable driving shalt fixed on the machine, a telescoping shaft and universal joints connecting said telescoping shatt with' the driving shaft and the work drive.

9. ln a grinding machine, a base, a tram-e mounted thereon to swing in a path transverse to the axis of the worlr, a work rotating shatt mounted on said trame, a telescoping shat't, a universal joint connecting said shafts, a rotatable, hollow driving member mounted in fixed position on the base surrounding said telescoping shaft, a universal joint between the telescoping shalt and said driving member and means to rotate said driving member at a uniform rate.

Signed at llorcester, Massachusetts, this 26th day oit Sept., i918,

ALBERT

Images