US2563170A - Honing machine - Google Patents

Description

w. P. HUNT l HONING MACHINE Aug. 7, 1951 2 Sheets-Sheet 1 Filed NOV. l5, 1946 INVENTOR.

w|LsoN P HUNT BY @mac 4am ATTORNEY Aug. 7, 1951 W, P HUNT 2,563,170

HONING MACHINE Filed Nov. 15, 1946 2 sheets-'sheet 2 44 8 l l FIG 3 E 3l 78 50 1 A ,7? Vw I i x82 @j ,f g l /80 y i- I/loo l m INVENTOR. WILSON P. HUNT 6AM c, QZ.

ATTORNEY Patented Aug. 7, 1951 mehr oFFicE HONING MACHINE Wilson P. Hunt, Moline, Ill., assigner to Moline Tool Company,l Moline, Ill., a corporation of Illinois Application November 15, 1946, Serial No. 710,164

12 Claims. v(Cl. 51--34) The invention relates to an improved hone and honing machine.

More specifically, the invention relates to an improvement in machines adapted to hone internal cylindrical bores such as those in automobile cylinder blocks which permit stones carried in a honing head to be moved outward an adjustable distance into contact with `the cylinder wall and then fed out slowly as metal is ground away and the stones wear while the head is revolving and reciprocating lengthwise of the bore.

Theinvention contemplates a hone construction wherein two cones are automatically moved axially of the hone to feed the stones out during the honing operation while providing independent adjustments foreach cone which permit the operator to expand either end more than the other should one end of the stones wear faster than the other.

One object of the invention is to provide a honing head containing two cones axially mov-y able in the honing head and adapted. to spread the stones. y

Another object is to provide a honing head containing two cones, each axially movable independent of the other, each adapted to spread on end of the stones in the hone. y

Another object is to provide a honing head containing two cones,v each axially movable indeependent of the other, with means permitting moving each cone while the hone is revolving and reciprocating. l Y

Another object of the invention is to provide a honing head containing two cones, concentric axially movable Aelements for moving the cones, an automatic cam mechanism for moving each axially movable element whileperrnitting manually modifying the movement of either cone independent of the other.

Another object of the invention is to provide Fig. l, partly in section., .isyan elevation of al honing machine equipped" with the improved hone shown in sectional elevation. 4

Fig; 2 is a front kView of the yspindle shown V.in Fig. 1.

2 Fig. 3 is a partial top View taken along line 3 3 in Fig. 1. f Fig. 4 is a section taken along line 4 4 i Fig. 1.

I is a cross rail of a honing machine of corrd ventional design. This cross rail slides in verti1 cal guides carried by housing I5 which rises from a bed or table I'I. This cross rail alternately moves up and down relative to the table. It is customarily moved by a hydraulic cylinder, not shown, placed inside the housing. The cross `rail I may carry finger 3l which engagesA adjustable lingers 33, 25 which are mounted adjustably' on a control rod 37 when the` cross rail reaches the end of its up or down stroke. Whenthus engaged the control rod is moved and this causes the cross rail moving mechanism to reverse its movement. The work to be honedis shown at i S as a sleeve supported on the table in any conventionalmanner. It may be held in a holder 2l having a bottom flange by clamps 23 tightened down by screws 25 in the holder. The holder may have a flange 21 which slidably supports it on the tableand the .holder may extend down into an opening 29 in the table, the opening being of larger diameter than the sleeve so that the sleeve holder may bel aligned with the axisof the hone. After the work has been properly centered it may be bolted to table I'I by bolts 22.

When honing is completed the cross rail is moved up beyond stop 33. Y

The cross rail carries a horizontal drive shaft d which carries a spiral lgear 3which meshes with another spiral lgear 5. This spiral gear 5 transmitsV rotary motion to a spindle 6 rotatablysupported in the cross rail I. This spindle carries at its lower end a cage-shaped yhoning vhead 'I. This head isalso of conventional design and .carries four radially movable. stone holders 8.

Each stone holder carries pins il, and Iiiy which extend through openings in the head .'I, preventing vertical or circumferential movements of the stone holder relative to the head. A long, narrow stone II is mounted in eachV stone holder.

A coiled garter spring I8 extends around the head I and engages the upwardly extending ears 2i) of each stone holder. The spring thus tends to draw the upper ends ofV all the stone holders inward. vA coiledgarter spring 3G is adapted to draw together the lower ends of the stone holders.

A sleeve i2 is `free to. slideup and down inside the'spindle 5 which is hollow. This sleeve .car-

,ries at its lower end a cone I4. This cone contacts. wedge-shaped surfacesl IB on the. pins@ .which are attached to the upper ends 'of the stone holders. The cone I4 is adaptedr'to pushjthe stones outward overcoming the springfIB when the sleeve I2 is moved downward inside spindle 6.

A rod 24 extends through the sleeve I2. At its lower end this rod carries a cone 26 which bears against the wedge-shaped surfaces 28 of the pins III connected with the lower ends of the stone holders.

Thus it will be seen that the stone holders always tend to move radially inward impelled.V

by the springs I8 and 36 but Ycan be moved outwardly by moving cones I4 and 26 downward. These cones may be moved downward automatically equal amounts to correct for the removal of part of the surface being honed and the wearing away of part of the stone when that wear is uniform throughout the length of the stone.

But it will be obvious that this arrangement also provides means for moving one end of the stones manually outwardfaster than the other. In this manner increased wear on one end of the stone'caused by conditions peculiar to the work being honed can readily be corrected.

It should be noted that this can either be accomplished by giving the two cones I4 and 26 the same slope and moving them different distances or by giving the two cones different slopes and moving them the same'distances. In the latter case, if the rod 24 and the sleeve I2 move together the two ends of the stones will automati- V cally be spread amounts which bear a fixed relation to each other.

To support the mechanism which moves rod 24 and sleeve I2 the cross rail I may have upwardly extending posts 40 which support two horizontal rock shafts 42 and 44. Clamped to the rock shaft 42 is an arm 46 and clamped to shaft 44 is an arm 48. The arm 48 carries a micrometer screw 50 which bears upon the enlarged head 52 of rod 24. A compressed spring 54 surrounds a part of rod 24. The upper end of the spring bears against the lower surface of the enlarged upper end 52 of rod 24 and its lower end against shoulder 56 in sleeve I2. Obviously, the spring 54 will tend to lift the rod 24 with its attached cone 26 against the micrometer screw 50 which limits its upward motion. Thus, by changing the setting of micrometer screw 58 the spread of the lower ends of the stones II can be altered. f

Riding loose on shaft 42 is a lever 60. An opening 62, considerably larger than rod head 52, extends throughlever 60. This lever 60 has two downwardly extending projections 64, one on each side of the opening. These projections bear upon a thrust washer 66 supported on Aballs free to rotate on a flange 61 which forms the upperend of the sleeve I2. A spring 68, which is considerably heavier than the spring 54, bears against flange 61 tending to lift the thrust bearing together with sleeve I2. The arm 46 carries a micrometer screw 18 which bears upon the outer end of the lever.60. It is clear that by turning the micrometer screw 18 the lever 60 can be moved and that the lever 60 will rmove the sleeve downward relative to spindle 6, and that this will spread the upper ends of the stones I I.

Thus, means have been provided whereby the operator can correct for different degrees of wear of the upper and lower ends of the stones. The micrometer screw may have a coarser thread than the screw 50 since the distance point 64 moves is less than the distance the outer end of the lever 60 travels. In this manner one turn of each micrometer screw will represent the same vertical movement of the cones I4 and 26 andv the.

same radial movement of the stones. However, the slope of the two cones can be so selected that if the micrometer screws 58 and 10 have the same pitch the two ends of the stones will still be spread the same amount.

It will be understood that a single cross rail may carry several spindles, all duplicates of the one described. The shafts 4, 42, 44, in that event all extend past all of the spindles so that whatever mechanism is provided to turn these shafts will turn all the spindles, spread the top of all stones equal amounts, and likewise spread the bottoms of all stones on all the honing heads equally.

In the manual adjustment just described the arms 46 and 48 remain stationary while the sleeve I2 and rod 24 are moved by the micrometer screws.

The invention also provides for automatically moving the stones in each head radially outwardly from their initial position while honing at a rate which will correct for the wearing away of the stones and for the increased diameter of the bore as material is removed from the surfac'ebeing honed. This is accomplished by automatically moving arms 46 and 48. Upon completion of the honing of one cylinder the arms resume their initial positions and the stones are automatically brought back to their initial position clear of the surface honed. It is now only necessary for the operator to move the micrometer screws 50 and 10 before honing on the next piece by the amount required to offset the wear of the stones which took place during the previous operation to make the hone ready to start work on the new cylinder with the stones in the same condition as they were when honing the previous sleeve. l

The stones are automatically moved outward in the head the proper amounts at the proper times as the honing operation progresses, by turning the shafts 42, 44 which carry arms 46, 48 appropriate amounts. This causes the arms 46, 48 to move the micrometer screws 58 and 10 down on rod 24 and sleeve I2 respectively and these in turn move cones 26, I4 which spread the stones.

To produce this outward movement of the stones in the honing head during each honing operation and withdrawing the stones thereafter, the shafts 42, 44 carry arms 12, 14 respectively. At the outer ends of these arms followers 16, 18 respectively are held in contact with two cams 60, 82 respectively. Each of these cams turns with shaft 84 which also carries a ratchet 86. The shaft 84 is supported on an upward extension 88 of the cross rail I.

Both of these two cams are generally involute in form but do not necessarily have the same rise. Each of these cams has a radial drop 80, 82 respectively. It will be clear that (Fig. 1) if the shaft 84 is slowly turned in a counterclockwise direction, each of the followers 16, 18 will follow its own cam 80, 82, and the shafts 42, 44 will be turned in a counterclockwise direction until the radial drop 90, '92 of the cam is reached at the end of the honing operation. Then the two arms 12, 14 will jump back in a clockwise direc'- tion to their original position, thereby allowing the garter springs to contract the stones.

These cams may be shaped to give practically any control of stone advance desired, but ordinarily they are shaped to expand the stones rapidly during the first stroke or two to secure con.- tact between the stones and the bore, thenl to expand gradually and uniformly, step by Step,

ascenso until the portion of the cam which corresponds to the desired size of bore is reached. After that the follower traverses a cylindrical portion of the cam giving a dwell during one or more strokes of the spindle without further expansion lof the stones. During this period the Apressure on the stones drops off and the stones are said to stroke themselves out. The drop is reached just before or during the withdrawal strokeV and the hone is contracted.

The two cams may be so designed that the upper and the lower ends of the stones are fed outward according to a dierent pattern or to different degrees. Thus, if in honing a particular type of sleeve the lower end of the' stone must do more work than the upper, the cam 82 may have a larger rise than the cam 80 which controls the spread of the upper end of the stone.

Upon completion of the honing operationthe upward pressure of the springs 54 and 68, acting on all of the spindles, will press arms 136 and 48 upward and thus will bring cam followers 16, T3 Aback into the position shown.

To secure the uniform slow motion ofV shaft 84 the arm S6 is loosely movable thereon. This carries a pivot e8 on which a ratchet arm IDD is pivoted. A vertical rod IGZ freely movable in a stationary party 2 carried by thethousing of the machine has a collar lili adjustably secured to the vertical rod. As the cross rail I moves up and down the collar 184 will, upon each down stroke, engage part 2 causing the ratchet to move forward one or several notches carrying with it the cams 80, 82. On the upstroke the weight of rod E02 and collar |04 will turn the arm 9c downward again until the arm 9E rests on a pin H35 carried by the extension 88.

Operation-In honing a cylindrical bore the cylinder block I9 is fastened into holder 2| resting on the fixed table I1 of the machinesand vertical reciprocation of thecross rail l is started. Continuously running shaft d through the spiral gears 3, 5 turns spindle 6 and the hone. The first down stroke of the cross rail brings the hone down into the bore to behoned after which it reciprcates with a stroke determined by setting iingers 33, 35 to bring theends ofthe stones slightly past the ends ofthe bore at each stroke. During the first few down strokes ratchet 8&5 moves the cams 8B and '82 so that followers 90, 92 pass over the quick rise portion of the cam, bringing the stones in contact with lthe bore. Then each succeeding strokebringsarms 56, i8 a little lower and this expands the stones a little more until the cylindrical part ofthe cams is reached. By this time :the :bore should be honed to size and this 'gives .the stones a chalice to make their final' strokes under' decreasing pressure. The stones are then contracted by the follower riding over the cam. In the last stroke the .cross rail rises higher and the hone `is also withdrawn fromthe bore. It stops in the up position .so that the cylinder may be removed and another placed inthe bed. A coolant is supplied while `the hone is` in 4operation through a pipe, not shown, and this coolant also washes away the particles removed from the bore by the hone.

After the cylinder has been removed anda new piece putin place the operator, :knowing how much the stone is worn down byneach piece honed, moves the micrometer screws 50 and JIJ the amounts necessary to provide the proper 'correction for the amount worn offthe surfaces.

lof vthe stones' during theY `previous honing operation. By movingthese two micrometer screws unequally the roperator can correct. for any greater wearthat may take place upon one end of the stonethanlthe other.

What'I claim is:

l. In a` honing machine,v a vertical frame, a cross rail slidably mounted on said frame, a verticalftool spindle rotatably supported on said cross rail, a honing tool having a cylindrical body supported on said spindle,` abrasive stones supported in said cylindrical body, means located at one end of the cylindrical body for spreading one end of each stone radially outward, a .rod extending through said tool vspindle for actuating said stone spreading means, a second means for spreading .the other end of each stone located at the other end ofthe cylindrical body, a sleeve extending throughsaid tool spindle and surrounding said rod for actuating said second stone spreading means, means lon said cross rail including a `shaft'carrying a cam having .successive portions with a rapid rise, a gradual rise, a dwell, and a drop adapted to engage said rod and another cam adapted to engage said sleeve forl progressively spreading said stones by moving thek rod and sleeve axially in the tool spindle and means connected to the frame for moving the shaft and cams at each reciprocation of the cross .rail on the frame.

2. In a honing machine, a vertical frame, a cross rail fslidably mounted on said frame, a vertical tool spindle rotatably supported on said `crossrail, a honing tool having a cylindrical body supported on said spindle, abrasive stones supported Lin said cylindrical body, means located at .one end ofthe cylindrical body for spreading one end of each stone radially outward, a rod extending through said tool spindle for actuating said stone spreading means, a second means for spreading the other end of each stone located at the other end of the cylindrical body, a sleeve extending through said tool spindle and surrounding said rod for actuating said second stone spreading means, means on said cross rail including ashaft carrying a cam having successive portions with a rapid rise, a gradual rise, a dwell, and adrop adapted toengage said rod andanother similar cam adapted to engage said sleeve l for progressively moving said stones radially by moving .the rod and sleeve axially in the tool spindle so that when the honing machine. is started after the hone has been inserted in the bore of a piece to be honed the stones will be movedk rapidly into contact with the walls of the bore, then fed gradually as the honing Vproceeds, then .held in radial position while the stones stroke out and are finally allowed to recede on completion of the honing, and means connected to the frame for moving the shaft and cams at each reciprocation of the cross rail on the frame. Y

3. A honing machine having a table, a vertical frame, va cross rail vertically movable on said frarnaa rotatable vertical hollow spindle supported by said cross rail, a cylindrical hone body carried by the vertical hollow spindle, abrasive stones carried in the hone body, rst means for.

moving the upper ends .of all the stones radially outward, a second means for moving the lower ends of all the stones radially outward, a sleeve in the hollow spindle engaging said rst means for moving the upper ends of all the stones, a iirst `spring bearing againstlthe sleeve and the spindle tending to elevate thesleeve, a rod in the sleeve engaging said second means for moving the lower ends of all the stones, a second spring bearing against the sleeve and the rod tending to elevate the rod relative to the sleeve, mechanism carried by the cross rail for depressing the sleeve against the rst spring, a second mechanism carried by the cross rail for depressing the rod against the second spring, cams mounted on a shaft supported on said cross rail, each cam controlling the position of one of said mechanisms, a ratchet wheel mounted on the cam shaft, a pawl actuated by the movement of the cross rail relative to the table to advance the cam shaft step by step, rock shaft assemblies carried by the cross rail, each rock shaft assembly including a follower which is engaged by one of said cams and an arm, the arm of one assembly tending to depress the rod against the second spring while the arm of the other assembly tends to depress the sleeve against said first spring.

4. In a honing device, a table adapted to support work having bores to be honed, a number of spindles adapted to enter said bores, a cross rail supporting said spindles and adapted to move said spindles into and out of said bores, a driving shaft assembly supported on the cross rail and adapted to rotate all of said spindles, a honing head carried by each spindle, stones supported in a radially movable manner in each of said heads, a sleeve axially movable in each spindle, a cone located within the hone body attached to said spindle adapted tov spreadone end of each stone radially, a rod axially movable inside said sleeve, a second cone located within the hone body attached to said rod and adapted to spread the other end of each stone radially, a rock shaft carried by the cross rail, rocker arms attached to the rock shaft adapted to move the sleeve relative to the spindle, a second rock shaft carried by the cross rail, other rocker arms attached to the second rock shaft adapted to move the rod relative to the spindle, mechanism supported on the cross rail including a single pair of cams each cam adapted to turn one rock shaft and its set of rocker arms, meansresponsive to the reciprocation of the cross rail toward and from the table to turn the cams step by step.

5. In a honing machine,y in combination, a vertical frame, a cross rail mounted on said frame and vertically movable thereon, a hollow honing spindle supported on said cross rail, a hone body supported on the lower'end of the spindle, stones radially movable in the hone body, means tending to draw the stones inward toward the center of the hone body, means including a rod extending down through the spindle to spread said stones, means on the cross rail adapted to rotate the spindle, a coil spring reacting against said spindle and a collar on the rod, a thrust bearing resting against the collar, a lever pivoted on the cross arm bearing on the thrust bearing, a second lever pivoted on the cross rail bearing against the rst lever, a shaft on the cross rail carrying a ratchet and a cam which bears against the second lever, a device engaging the vertical frame adapted to move the ratchet one step at each movement of the cross rail on the frame.

6. In a honing machine, in combination, a vertical frame, a cross rail mounted on said frame and vertically movable thereon, a hollow honing spindle supported on said cross rail, a hone body supported on the lower end of the spindle, stones radially movable in the hone body, means tending to draw the stones inward toward the center of the hone body, means including a rod extending down through the spindle to spread said stones, means on the cross rail adapted to rotate the spindle, a coil spring reacting against said spindle and a collar on the rod, a thrust bearing resting against the collar, a lever pivoted on the cross arm bearing on the thrust bearing, a second lever pivoted on the cross arm and carrying a manually adjustable screw which bears against the rst lever, a shaft on the cross rail carrying a ratchet and a cam bearing against the second lever, a device engaging the vertical frame adapted to move the ratchet one step at each movement of the cross rail on the frame.

7. In a honing machine, a vertical frame, a cross rail mounted on said frame and adapted to reciprocate up and down on said frame, a vvertical tool spindle rotatably supported on said cross rail, a honing tool having a cylindrical body supported on said spindle, abrasive stones supported in a radially movable manner in said cylindrical body, means located at one end of the cylindrical body for moving one end of each stone radially outward, a first rod extending down through said tool spindle for actuating said stone spreading means, a second means located at the other end of the cylindrical body for moving the other end of each stone radially outward, a second rod extending through said tool spindle for actuating said second stone spreading means, two mechanisms mounted on the cross rail, each mechanism adapted to move one of said rods respectively, a shaft supported on the cross rail, a cam carried by said shaft and adapted to move one of said mechanisms, a second cam carried by said shaft and adapted to engage the other of said mechanisms, a ratchet disc also carried by said shaft, a pawl coacting with said ratchet disc, means actuated by the reciprocation of the cross rail on said frame to actuate said pawl.

8. In a honing machine, a vertical frame, a cross rail mounted on said frame and adapted to be reciprocated up and down on said frame, a vertical tool spindlerotatably supported on said cross rail, a honing tool having a cylindrical body supported on said spindle, abrasive stones supported in a radially movable manner in said cylindrical body, means located at one end of the cylindrical body for moving one end of each stone radially outward, a rod extending through said tool spindle for actuating said stone spreading means, a second means located at the other end of the cylindrical body for moving the other end of each stone radially outward, a sleeve extending through said tool spindle and surrounding said rod for actuating said second stone spreading means, two mechanisms mounted on the cross rail engaging respectively said rod and said sleeve, a shaft supported on the cross rail, a cam carried by said shaft and adapted to move one of said mechanisms, a second cam carried. by said shaft and adapted to engage the other of said mechanisms, a ratchet disc also carried by said shaft, a pawl coacting with said ratchet disc, means actuated by the reciprocation of the cross rail on said frame to actuate said pawl.

9. In a honing machine in which after the hone is inserted in the bore of a piece to be honed lthe stones will be moved rapidly into contact honing, a vertical frame, a cross rail mounted on said frame and adapted to reciprocate up and down on said frame. a vertical tool spindle rotatably supported on said cross rail, a honing tool having a cylindrical body supported on said spindle, abrasive stones supported in a radially movable manner in said cylindrical body, means located at one end of the cylindrical body for moving one end of each stone radially outward, a rod extending through said tool spindle for actuating said stone spreading means, a second means located at the other end of the cylindrical body for moving the other end of each stone radially outward, a sleeve extending through said tool spindle and surrounding said rod for actuating said second stone spreading means, two mechanisms mounted on the cross rail engaging respectively said rod and said sleeve, a shaft supported on the cross rail, a cam having a gradual rise, a dwell, and a drop carried by said shaft and adapted to move one of said mechanisms; a second cam carried by said shaft having a gradual rise, a dwell and a drop and adapted to engage the other of said mechanisms; a ratchet disc also carried by said shaft, a pawl coacting with said ratchet disc, means actuated by the reciprocation of the cross rail on said frame to actuate said pawl, and manually actuable means carried by each of said mechanisms for moving the rod and sleeve endwise independent of said cams to correct the position of said stone for stone wear during a preceding honing operation.

10. In a honing machine, a vertical frame, a cross rail mounted on said frame and adapted to reciprocate up and down on said frame, a vertical tool spindle rotatably supported on said cross rail, a honing tool having a cylindrical body supported on said spindle, abrasive stones supported in a radially movable manner in said cylindrical body, means located at one end of the cylindrical body for moving one end of each stone radially outward, a sleeve extending through said tool spindle which when depressed actuates said stone spreading means, a first spring bearing against said sleeve and said spindle tending to elevate the sleeve, means located at the other end of the cylindrical body for moving the other end of each stone radially outward, a rod extending through said sleeve which when depressed actuates said last named stone spreading means, a second spring bearing against the sleeve and the rod tending to elevate the rod relative to the sleeve, two mechanisms mounted on the cross rail to depress respectively said rod and said sleeve, a shaft supported on the cross rail, a cam adapted to move one of said mechanisms, a second cam carried by said shaft and adapted to engage the other of said mechanisms, a ratchet disc also carried by said shaft, a`pawl coacting with said ratchet disc, means actuated by the reciprocation of the cross rail on said frame to actuate said pawl to move said disc and thereby cause said sleeve and rod to be depressed to spread the ends of said stone.

11. In a honing machine, a vertical frame, a cross rail mounted on said frame and adapted to reciprocate up and down on said frame, a vertical tool spindle rotatably supported on said cross rail, a honing tool having a cylindrical body supported on said spindle, abrasive stones supported in a radially movable manner in said cylindrical body, means located at one end of the cylindrical body for moving one end of each stone radially outward, a sleeve extending through said tool spindle which when depressed actuates said stone spreading means, a iirst spring bearing against said sleeve and said spindle tending to elevate the sleeve, means located at the other end of the cylindrical body for moving the other end of each stone radially outward, a rod extending through said sleeve which when depressed actuates said last named stone spreading means, a second spring bearing against the sleeve and the rod tending to elevate the rod relative to the sleeve, two mechanisms mounted on the cross rail to depress respectively said rod and said sleeve, a shaft supported on the cross rail, a cam adapted to move one of said mechanisms, a second cam carried by said shaft and adapted to engage the other of said mechanisms, a ratchet disc also carried by said shaft, a pawl coacting with said ratchet disc, means actuated by the reciprocation of the cross rail on said frame to actuate said pawl to move said disc and thereby cause said sleeve and rod to be depressed to spread the ends of said stones, and micrometer screws carried by each mechanism to move saidV rod and sleeve to permit the initial relative axial adjustment of rod, sleeve, and the vertical hollow spindle.

12. In a honing machine, a vertical frame, a cross rail mounted on said frame and adapted to reciprocate up and down on said frame, a vertical tool spindle rotatably supported on said cross rail, a honing tool having a cylindrical body supported on said spindle, abrasive stones supported in a radially movable manner in said cylindrical body, means located at one end of the cylindrical body for moving one end of each stone radially outward, a sleeve extending through said tool spindle for actuating said stone spreading means when depressed, a i'lrst spring bearing against the sleeve and the spindle tending to elevate the sleeve, means located at the other end of the cylindrical body for moving the other end of each stone radially outward, a rod extending through said sleeve for actuating stone spreading means when depressed, a second spring bearing against the sleeve and therod tending to elevate the rod relative to the sleeve, two levers pivoted on the cross rail to depress respectively said rod and said sleeve against said springs, a shaft supported on the cross rail, a cam adapted to move one of said levers, a second cam carried by said shaft and adapted to move the other of said levers, a ratchet disc also carried by said shaft, a pawl coacting with said ratchet disc, means actuated by the reciprocation of the cross rail on said frame to actuate said pawl to move said cams, a manually adjustable screw carried by one lever engaging said sleeve, and a manually adjustable screw carried by the other lever engaging said rod.

WILSON P. HUNT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED sTATEs PATENTS Number Name Date 1,793,486 Hunt Feb. 24, 1931 1,998,460 Kline Apr. 23, 1935 2,102,093 Quigley Dec. 14, 1937 2,164,811 Floss July 4, 1939 2,195,055 Wallace Mar. 26, 1940 2,229,318 Wallace Jan. 21, 1941 2,343,275 Caldwell Mar. 7, 1944 2,343,500 Fairbairn et al. 1---- Mal'. 7, 1944 FOREIGN PATENTS Number Country Date 131,542 Austria Jan. 25. 1933

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