US2480278A - Cloth-cutting machine - Google Patents

Description

Al1g- 30,1949- Y M. zAw|sTowsK1 2,480,278

CLOTH CUTTING MACHINE Filed Deo. 6, 1945 s sheets-sheet 1 Aug- 305 1949 ,l v M. zAwlsTowsKl 2,480,278

CLOTH CUTTING MACHINE ATTORNEYS M. zAw|sTowsK1 CLOTH CUTTING MACHINE Aug. 3o, 1949.

3 Sheets-Sheet 3 Fviled Deo. 6, 1945 INVENjroR Marian, ZawzsowS/'z/ BY QW/Mew ATTORNEYS 453ISA Patented Aug. 30, 1949 UNITED STATES PATENT '()FFICE CLOTH-CUTTING MACHINE l Martin Zawistowski, Huntington Station, N. Y. Application December 6, 1945, serial No. 633,167

11 Claims.

The present invention relates to portable cloth cutting machines of the reciprocating knife type having means for sharpening the knife whenever desired, and relates more particularly to the means for effecting movement of the sharpening members, and the application and control of actuating power thereto, and involves improvements over the construction illustrated in my prior Patent 2,282,918.

`The present invention involves improvements 2 the machine is far more compact and less liable to injury or displacements by objects coming in contact with' projecting parts.

Also the Sharpener carrying arms were pivoted in front of the guard bar so that it was necessary to swing around the bar, and thus idlers were in the positioning of the grinder wheel supporting arms in respect to the guard bar; the means for effecting the swinging movement of said arms; the means for effecting the down and up movements of said arms; the means for starting, re-

versing and stopping said up and down movements; and the means for effecting the application of power to impart these movements to the Sharpener wheels.

The main objects of the invention are to render the operating mechanism more compact and simpler in design, more accurate in operation and easier to control.

My present construction has many advantages over the construction shown in my Patent 2,282,918. In the form shown in that patent the clutch is normally in the middle or disengaged position, and to start the knife sharpening operation it is necessary to manually move the grinders downwardly a short distance and also manually operate a gear shifting member. As an important feature of my present invention no such manual operations are necessary. All that is needed is to momentarily push and release a small control lever.

As a further feature of the present invention the clutch is normally in engagement to lower the grinders. Therefore, upon closing the circuit the downward movement of the grinders starts automatically. The clutch is automatically shifted at the lower end of the Sharpener stroke, and is automatically shifted back to the original position when the Sharpener reaches the up-position, and the circuit is broken. Therefore, by a momentary movement of the control lever the grinders go through one cycle of operations and stop, and the cycle of grinding operations may be repeated as many times as desired.

In my prior patent above referred to the lead screw lil, the shafts 26 and the trip rod H5, extend to a very substantial distance above the motor. As a feature of the present invention the shafts, lead screw and trip rod are so designed and so arranged that they do not extend to any substantial distance above the motor, and thus required for the driving belts. As a feature of my presentY invention'the arms are journaled behind the guard. bar so that no such idlers are required.

"The invention involved vmany other features which will be apparent from, or pointed out in the description of the embodiment illustrated.

In the accompanying drawings I have illustrated only one embodiment of most of the operating parts and two embodiments of the power means, but it will be understood that many changes may be madeinthe details of construction and arrangements of the parts without departing from the scope of my invention.

In the drawing:

Fig. 1 is a front elevation of a machine embodying the invention. v

Fig. 2 is a side elevation, and showing in dotted lines the grinding wheel in sharpening position.

Fig. 3 is a view on a larger scale similar to a part of Fig. 1, and with many parts shown in section.

Fig. 4 is a side elevation showing the left side of the upper portion of the parts shown in Fig. 3 and with the parts in normal or rest position.

Fig. 5 is a View similar to Fig. 4, but with the parts in the position they occupy just after starting, or just before stopping.

` Fig. 6 is a transverse section through the reversing gear, on the line 6-6 of Fig. 3.

l Fig. 'll is a section on the line 1-1 of Fig. 6.

Fig. 8 is a vertical section in part on the line 8-8 of Fig. 6.

Fig. 9 is a section on the line 9-9 of Fig. l, the position of the grinding wheels being also shown in dotted lines engaging the knife.

Fig. 10 is a view showing the drive of the grind' ing wheels from the main motor, instead of from the separate motor, and

Fig. 1l is a front view of the parts shown in Fig. 10 with the control thereof.

The present invention is illustrated as applied to a type of machine which includes a base i, a vertical standard l'l, yand an electric motor l2 with operating connections to a vertically reciprocating knife i3. The base is ordinarily mounted on rollers and may be propelled and guided by a handlel, and the motor stopped and started by a suitable switch I5. In front of the lknife is a vertically adjustable guard bar I6 with a presser foot l'l adapted to rest upon the upper surface of the layers of cloth to be cut and beneath which layers the base I is moved. The guard bar may be adjusted vertically and locked in position by a suitable locking means operated by an oscillating member i8, as disclosed in my prior Patent 1,568,705.

The knife sharpening members comprise a pair 0f grinding wheels L9, mounted to swing horizontally in opposite directions into and out of engagement with the edge portion of knife and while rotating, may be moved down and up along the knife, substantially as shown in vmy prior Patents 2,282,917 and 2,282,918.

As shown particularly in Fig. 3, the power for actuating the grinders is a shaft 2-IJ -which has a worm 2| meshing with two worm wheels 22 on opposite sides thereto, whereby they are rotated in opposite directions. The worm wheels 2,2 are secured to parallel Vertical tubular shafts or sleeves 23, supported by `and rotatable lin spaced brackets V24 and 2,5 rigidly secured to the frame of the machine.

Disposed within, and s lidable lengthwise of said tubular or hollow shafts 23 are two parallel vertical shafts 26 which are keyed to their respective shafts 23 lso as to rotate therewith, but be freely sldable endwise in respect thereto. As shown, each outside shaft 23 has a pin or key 2|, slidable in a slot or keyway Y,28 extending lengthwise of the inner shaft. Thus, the inner shafts are simultaneously rotated with the outer hollow shaft and in opposite directions during their vertical movement, as hereinafter described.

Adjacent to, but spaced from, the lower end of each shaft 26 there is provided a sleeve 3|] journaled thereon and journaled in a vertically movable bracket 3|, and held against relative endwise movement in respect to said bracket. As shown, the upper part of each sleeve 30 has formed integral therewith, a gear wheel 32 resting on the upper side of the bracket and having helical teeth. Above each gear there is a collar 33 tightly clamped to the shaft by a set screw or other means.' Directly below the bracket each sleeve has rigidly secured thereto an arm 34 which carries a grinder wheel I9, as shown in Fig. 9. Thus, the sleeve is held against relative endwise movement in respect to the bracket 3| by the gears 32 and the arms 34.

The shafts 26 extend to a short distance below the arms 34, and these extensions are preferably square in cross section and carry pulleys 35. Beneath each pulley there is a spring washer 36, held in place and under tension by a collar 31, and between the upper surfaceof each pulley and the sleeve 3S there is mounted a friction washer 38 of felt or any other suitable material. Thus, as the bracket 3| is raised and lowered, the sleeves 30, arms 34, and pulleys 35 are raised and lowered therewith, and when said shafts are rotated, they drive the pulleys 35 and tend to frictionally turn the sleeves 30 to oscillate the arms 34. As shown particularly in Figs. 1, 2, and 9, the arms 34 rigidly carry depending pivot bolts 39, on which are rotatably mounted the grinder wheels I9 Secured to these wheels are pulleys 40, which are driven from the pulleys 35 by belts 4|.

For effecting oscillation of the arms 3 4 to swing the grinder wheels I3 into and out of operative position in respect to. the knife, there is provided a pair of rack bars 42 on the frame of the machine, and so positioned as to engage gears 32 during only the upper portion of the range of vertical movement of said gears, as shown in Fig. 2. The teeth of the rack bars and the teeth of the gears are so inclined, and the rack bars are of such length that, as the gears move endwise along the rack bars, they are rotated through approximately degrees, as shown in Fig. 9. When the gears 32 and the grinder wheels i9 are in their upper limiting position, as shown in solid lines in Figs. land 2, the arms extend outwardly and away from the knife i3. As the gears and ,grinder wheels descend, the gears swing the arms around into engagement with opposite sides of the edge of the knife i3, as shown in Fig. 9 and in dotted lines in Fig. 2.

When the gears pass beyond the lower ends of the rack bars, the grinder wheels are yieldingly pressed toward each other and against the knife, due to the friction between the pulleys 35 and the rotating sleeves 3i) which carry the arms. The wheels remain against the knife during the downstroke and during the upstroke, but when the gears again engage the rack bars, the arms and grinding wheels are positively moved away from the knife and back to the position shown in solid lines in Figs. 1 and 2. The ends of the teeth on the gears are preferably chamfered so that they will properly come into engagement Without liability of any direct abutment or jamming, when the gears are raised by the up movement of the bracket 3|, as will now be described.

For raising and lowering the bracket 3| together with the grinding wheels i9 and their drive shaft 26, I provide a threaded shaft 4", which may be driven in either direction by reversing gearing and a clutch, and from the shaft 2D. The threaded screw shaft 46 is held against endwise movement and telescopes into a tube l'i, which latter, at its lower end, is rigidly secured in a suitable manner to the bracket 3| above referred to, and at its upper end has an internally threaded portion 43 engaging the threads of the screw 46. Obviously, by rotating the screw 46 in one direction, the grinding wheels will be moved downwardly, and by rotating it in the opposite direction they will move upwardly.

For rotating and reversing the rotation of the screw, it is shown in Fig. '7 as having its upper end extending through a supporting bracket 4.5 and having a gear 5U meshing with a gear 5S on the upper end of one of the hollow shafts 23, which latter is driven from the shaft 29. The gear 50 is loose on the unthreaded portion of the screw shaft 46 and may be directly locked thereto for rotation in one direction, or locked thereto through reversing gearing for rotation in the opposite direction.

The gear 59 has formed integral therewith a beveled gear 5|, which meshes with a beveled pinion 52, which latter meshes with a second gear 53. The intermediate gear 52 has a stud shaft portion 54 journaled in the frame of the machine. Between the opposed beveled gears 5| and 53 there is provided a vertically movable clutch member 55, connected to the screw shaft i6 by a transverse pin 55 movable in a slot 51 in the shaft. This clutch member has teeth which may interlock with the upper gear 53 when the clutch member is in raised position, or with the lower gear 5| when the clutch member is in lowered position. Thus, upon rotation of the gear 56, the shaft 45 may be driven in one direction through the gear 5| and the clutch member to lower the sharpening wheels, or may be rotated in the opposite direction through the gears 5|, 52 and.

53 and the clutch member toraise the sharpening Wheels.

For operating the clutch there is shown a bell crank lever 59 pivoted at 60 and having Vone arm engaging the clutch andthe other armdepending for yieldingly locking it in position, as hereinafter .pointed out. The shaft 46-is held suspensed by a collar 6l, secured to the upper end thereof, and engaging the upperv side of the bracket 62, in which the gear 53 is -mounted,'and in which the bell crank lever 59 ispivoted.

Y In normal operation of the machine, in the cutting of cloth, the clutch member 55 is in its lowered position, as shown in Figs. `7 and-8, and the shaft 46 is thus connected to the shaft 20 for rotation of the screw shaft 46 in such a direction as will raise the grinding wheels I9, but the shaft 20 is not being rotated, and thereforethe grinding wheels remain at rest in the position shown in Figs. 1 and 2.

The shaft 29 may be intermittently driven by a separate electric motor 63, as'shown in Fig. 2, or it may be intermittently driven directly from the main motor I2, as shown in Figs. 9 and 10. Where a separate electric motor 63 is employed, it is directly connected to the shaftZD, and its circuit is controlled by a switch 64, disposed on the frame of the machine. The switch is operated by a push button 65, and when in its rest position, as shown ln Fig. 4, keeps the circuit of the motor 63 open. -The tubular carrier 41 for the grinding wheel supporting bracket 3|, at its upper end, has an arm 66 carrying a switch operating rod 61 vertically adjustable in respect thereto, and in alignment with the push button 65. Y' A switch releasing lever 68 is mounted -on a pivot pin 69 mounted in a bracket 62 from the frame of the machine, and has an operating handle 10. On the end of this lever is a pivoted latch 1l, and a coil spring 12 normally swings the lever 68 to such position that the latch is directly below the push button 65 of the switch and between it and the vertically movable rod 61."

With the parts in the rest position, as shown in Fig. 4, the grinding wheels have been raised by tube 41, and the latter has moved the rod 61 vup until it has engaged the underside of the latch 1I and lifted the latter and the push button'65 to open the switch so that the motor 63'is at rest. The lever 59 operates to reverse Athe clutch when the grinding wheels reach eitherv endr of their stroke. The lever 59 has a curved arm 14 disposed in an annular groove in the clutch collar 55, and also has an extension or arm 15, as shown particularly in Fig. 6. As previously noted, the clutch is normally in position to raise the grinding wheels. The lever 68 has a link 19 pivoted thereto, as shown in Fig. 6, and extending beneath the lever 59, as shown in Fig. 7. When the lever 68 is moved from the position shown in Fig. 4 and 'in solid lines in Fig. 6, to the position shown in -dotted lines to start the motor 63, a cam 89 on the link 19 at the same time engages beneath the lever arm 59 and raises the clutch to upper position where it interlocks with the upper bevel gear 53 to move the Sharpeners downward. Y Mounted on the frame of the machine is a vertically movable rod 8 I, shown in Figs. 3 and 6. This rod has a coil spring 82 resting on the arm 14 of the clutch reverser, and adjacent to its V'lower end it has a collar 83 which is adjustable `along the length thereof. When the grinding wheels approach the lower vend of their movement, an extension of the Aarm 66 strikes the collar v83 and'pulls the rod-8| downwardly and compresses the spring 82. When this spring pressure is sufficiently great to counteract the frictional grip of the clutch on the upper gear wheel 53, the spring acting on the arm 15 of the lever 59 snaps the clutch back to its lower position, and the Sharpener wheels start their up movement, when the rod 61 engages the lower side of the latch 1I it lifts it to apply pressure on the push button 65 and breaks the circuit of the electric motor.

Y To insure the holding of the clutch in the desired position the depending arm 11 of the lever 59 has a pair of ridges 84 and 85, either of which may engage a groove in the side of one of a pair of depending bars 18 on the bracket 68. Thus, in the position shown in Figs. 4 and '7, the ridge 84 is in engagement with the groove and the clutch is held in its lower position. When the clutch is raised to its opper position by the endwise movement of the link 19 and the cam 86, the ridge 85 will enter the groove and retain kthe clutch in its raised position.

When it is desired to start the knife sharpening operation, the lever 58 is turned on its pivot 69 by the operation of the handle 19, and from the solid line position shown in Fig. 6, to the dottedl line position. This moves the latch 1l out from between the rod 61 and the push button 65, and lets the motor 63 start operating to drive the grinding wheels and to rotate the gear 5l to start the swinging movement of the grinding wheels by the Aaction of the racks 42, and to start the rotation of the grinding wheels through the pulleys 35, belt 4l and pulleys 49. The lever 68 is immediately released so that when the rod comes up again, it will strike the latch 1|' and lift the push button 65, but it does not reverse the clutch.

If it is desired to repeat the grinding operation, the operator again presses the handle 10, to repeat the cycle of movement of the grinders. By having a steep pitch of thread on the screw 46, the grinder up and down movement may be very fast in respect to the rotary movement, and the wheels have more of a honing action than a grinding action.

It will be noted that the shafts 26 in their uppermost position do not extend much above the motor 63; that the arms 34 do not have to swing around the guard bar I6; that the operation of starting is effected by merely moving the latch 1I out from beneath the push button, and that the act of starting of the motor automatically reverses the clutch; and that all of the operating-parts are mounted close to the frame.

In the construction illustrated in Figs. l0 and 1'1 the electricmotor 63 is not employed, and the shaft 20 is driven from the main motor l2. This motor has a large disc 99 secured to the shaft 9| and provided with the usual link from a crank pin to the upper end of the knife holder.

Y I provide a lever 92 which carries a roller 93 for frictionally engaging the periphery of the disc, and'securedto said roller is a pulley 94 connected by a belt to a pulley 96 on the shaft 2D. The pulleys are of such relative sizes as will drive the shaft 20 and the grinders at the desired speed. Two pairs of pulleys are shown and of `different driving ratios so that the belt may be `put on either pair. 'A spring 98 may be employed for holding the roller firmly against the disc. Y

The lever has an arm 91 normally held in raised position by the end of the lever 68 so that the roller 93 is spaced from the disc 99. When the rlever V58 ismoved laterally the lever drops the sagome roller' onto the disc, and fthe `grinding operation starts. When 'the grinders return rto 'ltlfreir iup position, *the .rod i.' engages .the underside of the arm Si -and raises theroll'er o'ff the disc,and:smaps the arm above-'the lever F58.

tn the form shown 'in Figs. Tl itc 9 :inclusive the grinders may be used while fthe 'rknllffe :is .fat :cest 'or ywhile it is :being reciprocated lby the lmo'tor 112. In Ithe for-m shown in Figs. -120 :and lll the shampening is done only while the knife is bcingwrecirproca'ted, because 'both are-:driven by the vsaine mnotor.

Having thus described my invention, what 'I claim as new and desire to secure by Letters Patcutis:

l. A vcloth cutting machine of the reciprocating knife type having a iframe 'mem-ber, a pair of shafts and a ythreaded member depending therefrom, supported thereby, :and heldfagainst vertical movement respect thereto, fa vertically movable bracket, a pair 4of 'shafts and a threaded member extending upwardly therefrom :and held against ver-tical movement in respect thereto, knife sharpening members carried by said brack- 'et 'and driven by said last lmentioned shafts, Asaid upwardly extending shafts telescopi-ng with and keyed to said depending sha-f-ts, and said upwardly extending member telescopi-ng with rand having threaded connection to said depending member, gearing on said frame member for rotating said Shafts depending therefrom 'to there by 'rotate said 4second mentioned shafts, and reversing gearing on said frame Vmember for controlling the direction of rotation ieff said deber-id- 'ing member to thereby alternately raise and lower said bracket and said sharpening members.

2. A cloth cutting ina-chine of the reciprooating knife type having a frame member, a pair of shafts and a threaded member Adepending therefrom and supported thereby, and held against vertical movement in respect thereto, -a vertically movable bracket, a p r of shafts and a threaded member extending urdly therefrom and held against vertical movement in respect thereto,

knife sharpening members carried by saidbracket and driven by said last mentioned shafts, said upwardiy extending shafts teles-coping with and keyed to said depending shafts, and said upwardly extending member tei'es'coping with and havia tien to said depen-ding inch; "lg for rotating said shafts in one direction oni and said depending member alternately in opposite directions.

3. A cloth cutting machine of the reciprocating knife type having a frame member, a pair of shafts and a threaded member depending therefrom and supported thereby, and held against vertical movement in respect thereto, a vertically movable bracket, a pair of shafts and a threaded member extending upwardly therefrom and held against vertical movement in respect thereto, knife sharpening members carried by said bracket and driven by said last mentioned shafts, said upwardly extending shafts telescoping with and keyed to said depending f shafts, and said upwardly extending member telescoping with and having threaded connection to said depending member, means for rotating said shafts in one direction only, and means for alternately reversing the direction of rotation of said first mentioned threaded member.

4. In a cloth cutting machine 'of the reciprocating knife type including a frame member, a vertically movable bracket, two pairs of telescoping shafts, one shaft -of each pair boinc mounted in said frame member and the other .shaft of each pair :being mounted Eon `said bracket. a :pair 'of 'members connecting said frame 'and said Abracket and .having screw threaded connections, .means vfor rotating said shafts and one -of said members to move said bracket vertically, .a ipair of Ihelical gears .journaled in said bracket and concentric with .said shafts, arms rigid with said gears, .rotaitable :grinder stones j ournafled on said arms, :means operatively connecting lsaid stones 4and :said shafts, and stationary vertically disposed rack bars in the path of vertical movement of `said helical gears for swinging said arms to bring said grinder stones into and out of opferative 'engagement with said knife.

5. In a #cloth fcutting machine having a frame, a motor mounted thereon, a pair of shafts mounted on :said fname and held against endwise movement, means at the upper e'nd of said :frame and driven by said motor for rotating I'said lshafts in opposite directions, a vertically movable bracket -slidable on said frame, la threaded :member on said bracket, means driven by said motor and engaging with said threaded member for raising and lowering said bracket, a pair of shafts extending upwardly from said bracket and having their lower ends journaled therein, each telescoping with and keyed to one of the rst mentioned shafts, knife sharpening members support- -ed by said bracket, and means operatively connecting said stones and said shafts.

6. In a lcloth cutting machine having a frame. a pair of depending shafts mounted thereon, motor driven means at the upper 'end of said vframe for rotating said shafts in opposite directions, a vertically movable bracket, a pair of shafts journaled therein and extending upward- .ly therefrom, each telescoping within and keyed to one of the first mentioned shafts, a vertically movable member connected to said bracket for effecting telescoping of said shafts, knife sharpening members supported by said bracket, means operatively connecting said stones and said shafts, and motor driven means engaging said member for moving said bracket up and down along the knife.

'7. In a cloth cutting machine of the type which includes a frame, a vertically disposed reciprocatory knife, rotatable grinder stones for sharpening said knife and movable up and down along the length thereof, and a motor for reciprocating said knife, a pair of vertical shafts each Vcomprising upper and lower telescoping sections, the upper section being held against endwise movement by said frame, means operatively connecting the lower section to said stones, a vertically movable bracket in which said lower shaft sections are journaled, arms pivotally mounted on said bracket, concentric with said shafts and supporting said stones, a threaded member held by said frame against endwise movement, means connected to said bracket and engaging said threaded member for telescoping said shaft sections and moving said bracket down and up along said knife, gearing for rotating said shafts, and gearing for rotating said threaded member first in one direction and then in the other to raise and lower said bracket and thereby move said stones along said knife.

8. In a cloth cutting machine including a frame, a vertically disposed reciprocatory knife, a. motor for reciprocating said knife, a. pair of vertical shafts driven by said motor and each comprising upper and lower telescoping sections held against relative rotation, the upper section being held against endwise movement by said frame, a vertically movable bracket in which said lower shaft sections are journalled, arms mounted on said bracket and pivoted on axes concentric with said shafts, knife sharpening members journaled on said arms, means operatively connecting said stones and said shafts, a threaded member held against endwise movement by said frame, means engaging said member for raising and lowering said bracket and thereby telescoping said shaft sections, gearing driven by said motor for rotating said shafts, gearing for rotating said threaded member. and gear shift mechanism to reverse the direction of rotation of said threaded member at the ends of the path of movement of said bracket to raise and lower said bracket and thereby move said stones along said knife.

9. In a cloth cutting machine of the type which includes a frame, a vertically disposed reciprocatory knife, rotatable grinder stones for sharpening said knife and movable up and down along the length thereof, and a motor for reciprocating said knife, rotating said grinders and moving them along said knife, said machine being characterized by a pair of vertical shafts each comprising upper and lower telescoping sections held against relative rotation, the upper section being held against endwise movement by said frame, means operatively connecting the lower section and said stones, a vertically movable bracket in which said lower shaft sections are journaled, arms pivotally mounted on said bracket, concentric with said shafts and supporting said stones, a threaded member driven by said motor for raising and lowering said bracket and thereby telescoping said shaft sections, gearing driven by said motor for rotating said shafts, and gearing driven from one of said shafts for rotating said threaded member first in one direction and then in the other to raise and lower said bracket and thereby move said stones along said knife.

10. In a cloth cutting machine of the type which includes a frame, a vertically disposed reciprocatory knife, rotatable grinder stones for sharpening said knife and movable up and down along the length thereof, and a motor for reciprocating said knife, rotating said grinders, and moving them along said knife, said machine being characterized by a pair of vertical shafts each comprising upper and lower telescoping sections, means operatively connecting said stones and said lower section, a vertically movable bracket in which said lower shaft sections are journaled, arms pivotally mounted on said bracket, concentric with said shafts and supporting said stones, a threaded member driven by said motor and held against endwise movement by said frame for raising and lowering said bracket and thereby telescoping said shaft sections, and motor driven gearing for rotating said shafts in one direction, and for rotating said threaded member rst in one direction and then in the other to raise and low-er said bracekt and thereby move said stones along said knife.

11. In a cloth cutting machine having a frame, a motor carried thereby, a pair of hollow shafts carried by said frame and held against upward movement, means at the upper ends of said shafts and driven by said motor for rotating said shafts in opposite directions, a vertically movable bracket, a pair of shafts extending up from said bracket, each of said last mentioned shafts telescoping with one of said first mentioned shafts and keyed thereto, a vertically movable thread-ed member extending upwardly from said bracket and held against rotation, a screw engaging said threaded member, driven from said motor, and disposed alongside of said hollow shafts, means driven by said motor for rotating said screw and including gearing, means for Vshifting said gearing to alternately raise and lower said bracket and telescope said shafts, knife sharpening elements carried by said bracket, and means operatively connecting said shafts to said elements.

MARTIN ZAWISTOWSKI.

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

UNITED STATES PATENTS Number Name Date 1,173,983 Perlman Feb. 29, 1916 1,815,018 Wagner July 14, 1931 2,183,788 Clark et al. Dec. 19, 1939 2,282,918 Zawistowski May 12, 1942

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