US2156798A

US2156798A - Cloth-cutting machine

Info

Publication number: US2156798A
Application number: US202430A
Authority: US
Inventors: Bangser William
Original assignee: MAIMIN Co Inc H
Current assignee: H MAIMIN COMPANY Inc; MAIMIN Co Inc H
Priority date: 1938-04-16
Filing date: 1938-04-16
Publication date: 1939-05-02
Anticipated expiration: 1956-05-02

Description

May 2, 19.39. wpBANGsER CLOTH-CUTTING MACHINE Filed April 1e, 193e 6 Sheets-Sheet 1 lNv NToR BY U www ATTORNEYS May 2, 1939. wj BANGsER CLOTH-CUTTING MACHINE Filed April 16, 1938 6 Sheets-Sheet 2 if?

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46 ,39 735 f7 4.5

lNvE TQR Bix/Jam' M AT1-cantv:

May 2, l939- w. BANGSER 2,156,798

CLOTH-CUTTING MACHINE Filed April 11.6,v 1938 6l Sheets-Sheet 3 INV TOR ATTO RNEY May 2, 1939. w, BANGsl-:R A 2,156,798

CLOTH-CUTTING MACHINE Filed April 16, 1958 6 Sheets-Sheet 4 gif/,

INV TOR ATTORNEYS e sheets-sheet 5 nlNvEN on ATTORNEYS a 'lll/lll May 2, 1.939.4 w. BANGSER CLOTH-CUTTING IACHINE Filed April 16, 1938 May 2, 1939. w. BANGsER 2,156,798

0mm-comune momma ATTORNEYS Patented May 2, 1939 CLOTH-CUTTING MACHINE William Bangser, New York, N. Y., assigner to H. Mamin Company, Incorporated, a corporation of New York Application April 16, 1938, Serial No. 202,430

18 Claims.

This invention relates to cloth-cutting machines of the reciprocating knife type and particularly to means for sharpening the knives of such machines.

Various means have been proposed for sharpening the knives of cloth-cutting machines ci' the reciprocating knife type by power-driven means, but all of them, so far as I am'aware, have been objectionable because the stones have been so mounted as to impair the full cutting capacity of the machine and obstruct the operator's view when not in use. In accordance with the present invention I have so mounted the stones that when not in use they are swungforward away from the knife and upward, thus permitting the operator to employ the full capacity of the machine for the thickest lays, and, also permitting him an unobstructed view of the line of pattern markat the point of cutting. Doing this has involved the provision of means formoving the stones outside of the presser foot guard 4at the completion of the grinding operation and for moving them inside of the guard for grinding.

During cutting the stones preferably, carried on swinging arms, are swung forward of the guard ,and held well above and beyond the upper end of the knife. To sharpen, the stones are. rotated, swung on their arms around the guard and into grinding contact one with either side of the knife. 'I'he stones, still rotating, are moved down the length `of the knife edge, the traverse reversed,

and are then-swung out into inoperative position,

thus completing the grinding cycle. In thepreferred embodiment of my invention this cycle requires the action of the operator for its initiation only, the driving mechanism being automatically Athrown out of operation at the end-of the cycle.

As the grinding takes place without removing the presser foot the cycle cannot be completed unless the presser foot is in its lowermost position. Should the operator neglect tolower the presser foot to its lowermost position before initiating the grinding cycle, the machine would be seriously damaged. I have, therefore, provided several means for avoiding this accident; One,

arranging the starting mechanism so that 'the grinding cycle cannot -be initiated until the pressl er foot has been lowered; two, vproviding means for automatically interrupting the downward movement of the stones immediately before engagement with the presser foot; andy three, making the presser foot guard extensible and. movable with the stone carriage. v

Inorder that the stones shall grind the edge oi' the knife without engaging each other, one is placed slightly in advance of or below the other. If both faces of the knife are to be ground throughout their entire lengths and the point of the chopping edge or bottom bevel ground, the forward or lower stone must pass beyond the end of the knife. As the stones are springpressed toward the knife in order to take up wear the stone passing the end of the knife swings in and on the upward stroke .forms a burr on the bottom bevel which seriously interferes with efflcient cutting. A'Io avoid this difliculty I provide one double and one single stone, with the plane of the single stone intermediate the planes of the two sections of the double stone. The upper section of the double stone bears against the knife when the lower element has passed the lower edge and this prevents the latter from swinging undervthe knife and forming a burr.

In the accompanying drawings I have illustrated two different mechanisms for moving the stones through the grinding cycle. In the first, the mechanism is driven from the motor which reciprocates the knife; in the second, a separate driving motor is provided. In these drawings Figure 1 is aside elevation of Va conventional cloth-cutting machine of the reciprocating knife type showing in vertical section a grindstone actuating mechanism driven from the main motor of the machine; Figure 2 is an elevation of the upper end of the machine of Figure 1 viewed from the other side; Figure 3 is an end elevation of that part of the machine shown in Figure 2; Figure 4 is a detail of the starting mechanism showing the means for preventing starting until the presser foot is in. its lowermost position; Figure 5 is a transverse section taken along line 5 5 of Figure 3; Figure 6 is a vertical section on a somewhat` enlarged scale taken along line 6-6 vof Figure l; Figure 'l is a transverse section taken along line 1 1 of Figure 6; Figure 8 is a transverse section taken along line 8-8 of Figure 1; and Figure 9 is a transverse section taken along line 9-9 of Figure 6. Figure 10 is a side elevation of a conventional cloth-cutting machine of the reciprocating knife typeV provided with a stone-actuating mechanism driven by a separate motor; Figure 11 is a longitudinal vertical section on a somewhat y is\a transverse section taken along line' IS-IS of Figure 11; Figure 16 is a detail showing the rela'- Figures l. through 9. The cloth-cutting machine there illustrated comprises the usual base l on which is mounted a standard 2 carrying a motor 3 and a motor housing 4. A knife 5 is mounted for reciprocation in a vertical slot inthe forward edge of the standard. The reciprocating mechanism comprises a cross-head o, a pitman 1 and a crank 3 mounted on a fly-wheel 9 on Athe motor shaft. The operation of the motor is controlled by a switch I0 and the whole machine guided by means of handle ll. Mounted for vertical adjustment immediately in front of the knife 5 is a presser foot i2 carried by a guard i3. The foregoing is standard construction and of itself forms no part of the/present invention.

I shall now describe how the grindst'ones are mounted and swung. Mounted on `the front of the motor housing is a fixed grinder frame i5 having vertical guideways it in which is slidablyvmounted a grinder slide il closed at its lower end by a plate lll extending inward toward the :motor housing. On the inner end of this plate i@ are mounted two vertical spindles i9 carrying at their lower ends plates 28 on which grindstone studs 2l are mounted, these

studs carrying grindstones

22 and 23. A coil spring 28 encircles each spindle, hxed at one end to thefspindle, and at the other to the plate i8. These springs normally urge the plates 20 to assume the position shown in Figure 8 and in dotted lines in Figure l with the stones in grinding contact with the edge of the .knife 5. In order to swing the stones out of contact with the knife at the upper end of their traverse and permit them to clear the lower end of the motor housing, l provide two xed threaded nuts 25 (see ligure l) between the grinder frame it and the motor housing adapted to receive the upper ends of the spindles l 9.

The upper ends of these spindles are provided with threads 28 of large pitch so that in passing through the nuts, with which they make thread-` ed engagement, the spindles are rotated through angles of something more than 150 against the action of springs 24 and the stones thereby swung outward to assume a position immediately below the grinder frame, as illustrated in Figures 1, 2, 3, 6 and 7. In this position they do not obstruct the vision of the operator.

I shall now describe the mechanism which rotates the grindstones. Journaled within the slide I1 is a square shaft 28 on'the lower end of which is xed a pinion 29 which, through

gears

38, 30'

v and 3|, rotates the stone 22 in a clockwise direcis xed a pinion 38 meshing with gear 39, also.

tion, as viewed in Figure 8, and through

gears

32, 33, 33' and 34 rotates stone 23 in a'counterclockwise direction. The

gears

30 and 30 are fixed upon the jsame stud and rotate together.

'Ihe same is true of*

gears

33 and 33. .Square shaft 28 passes slidably through a square hole in a bevel pinion 35 journaled in a plate 36 mounted on the fixed grinder frame I5. Bevel pinion 35'mesl1es with another bevel pinion 31, journaled in the frame I5, on the shaft of which journaled on the grinder' frame, which meshes in turn. with a pinion 40 journaled in a rocker arm 4I pivoted at 42 and coaxial with friction drive wheel 43 designed to make frictional driving engagement with the :dy-,wheel 9 of the motor. When the friction wheel 43 is swung into contact aisance grinder frame l5 are two sprockets 45 around which pass a chain 46. One link of this chain is.

provided-with a roller 41 lying within a slotted block 48. xed to the upper end of the slide l1. Movement of the chain thus reciprocates the slide I1 in its guideway i6 and with the slide the grinstones, reciprocate likewise. The stones are positively rotated throughout the reciprocation of the slide by virtue of the fact that the square shaft 28 can movey vertically with reference to the pinion 35 while, at all times, being driven by that pinion. The chain is driven through the following reducing gear train: a pinion 49 fixed to and rotating with the gear 39 meshes with a gear 58 to which is fixed a pinion 5l meshing with a gear 52 on the shaft of the lower sprocket 45. Thus rotation of the friction drive wheel 13 not only rotates the grindstones, but causes them to traverse the length of the knife, that is the effective cutting range of the knife, and back.

I shall now describe how the grinding cycle is initiated and how the mechanism which effects it is automatically thrown out of `operation at the end of one cycle. The cycle is initated through the operation of a trigger 54 mounted on one side of the grinderl frame l5. This trigger is provided with a trigger shaft 55 iournaled within a sleeve 56. At the inner end of the trigger shaft 55 is fixed a short arm' 51 on which is pivotally mounted a longer arm 58 urged toward the machine by means of coil spring 59. The lower end of the arm 58 is connected to the rocker arm 4| by meansjof a toggle link 60. With the parts arranged as `shown in Figure 4 with the arm 51 on the trigger shaft held fixed by means of a trigger latch, tobe described presently, the toggle link is so positioned that the spring 59, acting through arm 58, holds the friction drive wheel 43 out of contact with the fly-wheel 9 of the motor. In order to move the friction wheel 43 into driving contact with the ily-wheel, the trigger,- trigger shaft and arm 51 are swung to the right, as viewed in Figure 4, until the lower ltaggle joint passes tothe right of a line extend- Mounted on the trigger is a trigger latch 62u ,i

the lower arm of which engages a trip 63 mounted on the front of the slide I1 and normally holds the trigger in the position shown in Figures 3 and 4, that is, with the driving wheel out of con- .tact with the ily-wheel. The upper arm of the latch is normally urged away from the trigger by means of a leaf spring 64.

The apparatus just described operates as follows: In order to initiate the grinding cycle, the operator grasps the upper ends .of the trigger and triggerlatch vbetween the thumb and foreflnger and draws them together, thus freeing the latch -from the trip. 'I'he trigger thus freed is into contact with the fly-wheel,.as described before. It we assume that the fly-wheel is rotating, thegear trains are set in motion and three things' happen: one, the grindstones are rotated, two, .the slide moves downward, and three, cooperation between the xed nuts 25 and the 75 guapos the cycle. When the slide reaches its uppermost 'f position, however, as shown in Figure 6, where.

continued operation of the mechanism'would re. peat the vcycle just described, the trip 63 engaging the lower end of the latch A62 throws the trigger to the left and through the action of the.

toggle 60 snaps the driving wheel out of contact with the rotating fly-wheel.l In order that there should be no over-running of the mechanism, I provide a fixed brake shoe 6l which engages the driving wheel 43 when it is swung out of contact with the fly-wheel.

I shall now describe the means which I have devised which make it impossible to operate the grinding mechanism until the presser foot has -been lowered into contact with the base l. As shown best in Figure 4, the rocker arm 4| which carries the frictionV drive wheel 43 is provided with a vertically extending arm 66 provided with an inturned end 61. When the presser foot is in any raised position, the guard i3 projects beyond the end 61 of the arm 66. Thus should the operator attempt `to swing the trigger so as to throw the grinding mechanism into operation he would be unable to effect his purposev because the end 61 would bear against the guard I3 and make it impossible for the toggle 60 to snap the drive wheel 43 into contact with the fly-wheel. When the presser foot is resting upon the base of the machine, however, the upper end of the guard I3 is not so high that the end 61 of the arm 66 may not be swung over it. l

As shown in Figures 6 and 16, the grindstone 22 comprises two axially separated sections mounted on a single stud, whereas grindstone 23 comprises a single section, the plane of which is intermediate that of the two sections of the other stone. At the lgwer end of the traverse the `stones occupy the position relative to the knife shown in Figure 16, the knife being shown at the lower end of its reciprocation. It will be notedthatthe lowersection or element of the stone 22 has completely passed-the knife and were this section separately mounted, the action of the spring urging it into grinding contact withl the stone would tend to swing it beyond the edge of the bottom bevel so that on the return movement a burr would be turned on the bottom bevel. As the sections of the stone 22, however,

' are rigidly connected, being mounted on a single stud, this action cannot occur, the upper section bearing against the knife and holding the lower one in alinement. It would be possible, of course, to substitute a non-grinding element for the upper section, but I have found it more satisfactory to employ two grinding elements.

I shall now describe the modied form of actuating mechanism illustrated in 4Figures 10 through 15. The cloth-cutting machine itself, shown in these iigures, is precisely the same as the one illustrated in the other gures and need not be described again.

I shall ilrst describe` how the grindstones of this modified mechanism are mounted and On the upward move" swung. pivotally mounted at 1o on me front 'Y of the motor housing is a frame 1| having trackways 12 on which is slidably mounted a grinder slide 13 closed at its lower end by plate 14 extending inward toward the motorhousing. Pivotally mounted at 115 on the lower face of plate 14 are a pair of arms 16 extending inward toward the machine and carrying at their ends grindstones 11 which are, so far as the stones are concerned, precisely like the

grindstones

22 and 28 described in connection with the other form of device. Extending upward through arcuate slots 1'8 in the plate 14 are pins 'I9 to which are pivotally connected curved arms 80 the inner ends of which are reduced in width to form tongues 8| and shoulders 82. overlap and are straddled by the bifurcated end of an arm 83 pivotally mounted on a cross bar 84 carried by the slide 13. The curved arms 80 are connected by means of a coil spring 85 which urges the arm 16 and the stones 11 toward each other and into contact with the edge of the knife The tongues 8|v during the grinding operation, as illustrated in dotted lines in Figure 14. The upper end of the arm 83 carries a roller 86 which, when in engagement with the rear wall of the frame 1|,

swings the bifurcated lower end of the arm 83 against the shoulders 82 and, through the curved arms 80, swings the arm 16 and the stones 11 apart, as shown in Figures 14 and 15.

I shall now describe the mechanism which rotates the grindstones. Mounted on the slide 1?.A

is a motor 89 controlledl by a switch 90 operated by means of a switch arm 9|. A pinion 92 on the motor shaft neshes with a gear 93 on a shaft 94, the lower end of which carries a gear 95 which, through gear trains 96, '91 and 98, and 99, |00 and |0| carried by the plate 14 rotates the stones.

I shall now describe the mechanism for traversing the grindstones. Mounted on the inner face of the slideV 13 are sprockets |02 around which extendsA a' chain |03. One link of this chainis pivotally connected to a bar |04 pivoted at v|05 to the frame 1|. The lower sprocket |02 is fixed' to a shaft |06 on which is journaled a bevel gear i01 meshing with a bevel pinion |08yxed on shaft rying the motor, the chain, the yvarious gear trains and the stones to move relative to frame and all of the grinding mechanism carried by it is held at an angle to the vertical during normal cutting operations with the stones beyond the presser foot guard and above the handle of the machine. The frame is held in this position by means of an arm H5 pivotally mounted on the motor housing at |16 and normally held vertically in the dotted line position of Figure 10 by means of a spring ||1. 'Ihe outer end of the arm H6 is provided with jaws 8 designed to engage a roller H9 on the bar 84 in a manner to bedesoribed preesntly.

The apparatus just described operates as follows: The operator swings switch arm 9| down to close the switch 90 and start the motor 89. As the slide 13 moves downward, the stones rotating, the arm ||5 is swung about its pivot ||6 and the frame 1|, urged by a spring |20, tends I 1l. As shown in Figures 10 and 11, the frame 1| vto assume a verticalpcsition. in the downward tinue their downward traverse rotating in grinding contact with the knife blade and then reverse their travel due to the action of the chain. m3. On the upward traverse the operations performed on the downward traverse are reversed.

.Roller il@ enters vbetween the jaws it@ of the arm M5 just as roller engages cam surface |2|. Thus as the frame lli is sg outward about its upper pivot it, the stones are swung out on their arm it and pass the presser foot guard. In order to stop the mechanism at the completion of a single grinding cycle, one link of the chain w3 is provided with a lug 622 which engages a pin B2i on the switch arm extending through a slot l2@ in the slide 713. The path of the lug |22 being along an arc of sler radius of curvature than the path traversed by pin U23, the lug and pin are disengaged at the moment the switch is opened. During the grinding operation the knife should be reciprocating.

In order that the stones may not necessarily remain in their widest spaced relation when not' in use, I provide an opening i255 in the back of the frame 'H through which the roller may project and permit the spring 35 to draw the stones closer together than they otherwise would be so as not to interfere with the vision of the operator.'v

I' have provided the grinding mechanism illustrated in Figures l through 9 with a safety de-- vice which makes it impossible for the operator to start the grinding action if the presser foot is Y not in its lowermcst position. i have provided the grinding mechanism shown in Figures l0 through 15 with a dierent type of safety device. This device although permitting the operator to -start the grinding mechanism with the presser foot in elevated position, nevertheless automatically throws the switch and stops the mechanism before the stones reach the presser foot. This safety device consists of a rod i2@ terminating at its upper end in a. yoke it?? which straddles and is pivotally connected to the switch arm 9i. The lower end of the rod slidably engages a hole in the plate l and terminates in a crooked end |28. When the operator swings' the switch arm Si downward to close the switch and initiate the grinding cycle the crooked end itt of the rod |126 is moved into the dotted line position shown in Figure l0, just below the stones. lf, during the downward traverse of the stones the end of the rod |26 should engage the presser foot, inadvertently left in raised position, the f switch would be immediately opened and the mechanism stopped before any damage could be done.

In Figure 17 I have illustrated the third safety device invented by me. This comprises a telesqoping and extensible presser foot guard. The presser foot 3u is mounted on the end of a square rod 63| which nts within a square rsleeve G32 closed at itssupper end. i coil spring E33 con- A.nects the upper end of the rod itl with the upper closed end of the sleeve H32 and tends to hold the presser foot in abutment with the lower and open end of the sleeve |32. The sleeve G32 and the rod ticular lay being cut'.v When. used on a chine anaemia employing either type of grinding mechanism described in this application, but lacking any other safety device, the stone mountings descending in the downward traverse of the grinding mechanism engage the presser foot and, acting against the spring |33, cause the rod iti to slide downward relative to the iixed sleeve |32. 0n the return traverse of the stones, the presser foot follows them, being moved upward by the retractile spring |33. After the grinding, the presser foot is in the same position of adjustment as it was before. y

In using either of the grinding mechanisms described, the machine must, of course, be first removed from the cloth. Unless anextensible presser foot guard is employed the presser foot must be set in its lowermost position before the grinding cycle is begun. When g the grinding mechanism, shown in Figures l through n, it would be impossible for the operator to start grinding until the proper adjustment of the presser foot had been made. Using the form of grinding mechanism shown in the other gures, the grinding operation might be started, but it would be automatically arrested just before the stones encountered the presser foot in the event that the latter had not been previously lowered. When the stones are not in use they are carried above the upper end of the stone and yond the guard. In` this way the full cutting capacity of the stone can be used and the stones, when not in use, do not obstruct the operators view ci' the line of the pattern marks at the point of cutting. By the use of the double stone the point of the bottom bevel of the knife is sharpened without the formation of an objectionable burr.

I claim:

l. In a cloth-cutting machine of the reciprocating knife type having a guard, the combination of stones for sharpening the knife mounted, when not in use, beyond the guard, means for rotating the stones, means'for moving the stones past the guard while the latter is in operative position and into grinding engagement with the knife, meansfor traversing the stones along the length of the knife and back, and meansior nieving the stones past the guard while the latter is still in operative position and into their original position at the end of the grinding cycle.

2. In a cloth-cutting machine of the reciprocating knife type having a guard., the combination of stones for sharpening the knife mounted, when not in use, above the upper end of the krn'fe and beyond the guard, means for rotating the stones, means for swinging the stones around the guard and into grinding engagement with the knife, means for traversingr the stones along the length of the knife and back, means for swinging the stones around the guard and into their original position at the end of the grinding cycle, a source of power for the rotating, swinging and traversing means, manual means tor 'applying the power to initiate a grinding 4cycle and means for automatically turning oi the power at the end of the cycle.

3. In a cloth-cutting machine of the reciprocating knife type, the combination of a frame carried by the machine, a slide slidahly mounted in the frame, a pair of swinging arms carried by the slide, stones for sharpening the knife mounted on the arms and lying beneath the frame when not in use, means for rotating the stones, :meansy for swinging the arms to bring the stones into grinding engagement with the knife, means for moving the slide relative to the frame to traverse the stones along the length of the knife and back, and means for swinging the stones back into their original position beneath the frame at the end of the grinding cycle.

,4. In a cloth-cutting machine of the reciprocating knife type, the combination of means for sharpening the knife comprising two stones, one on either side of the knife, one stone comprising two vertically,spaced sections -rigidly mounted relative to each other, and the other stone oomprising a section lying in a plane intermediate the plane of the two sections of the double stone, means yieldably urging the stones into grinding contact with the knife, means for traversing the 'stones along the 1ength of the knife until the lower section of the double stone passes beyond the bottom bevel of the knife, the upper section bearing against thel knife and preventing the yieldable means from moving the lower section under the bottom bevel of the knife.

5. In a cloth-cutting machine of the reciprocating knife type, the combination of stones for sharpening the knife, mountings for the stones, means for moving the stones and their mountings up and down along the knife, a presser foot mounted on a telescoping guard, and a spring urging the guard sections into telescoping condition, the guard extending upon engagement of the stone mountings with the presser foot and returning to its original condition when such engagement ceases.

6. In a cloth-cutting machine of the reciprocating knife type, the combination oi' a plate movable relative to the knife, a pair oi spindles carried by the plate, swinging arms fixed to the spindles, stones for sharpening the knife mounted on the arms, threaded extensions on the spindles, fixed threaded nuts on the machine with which the spindles make threaded engagement when the plate is in its upper position and means for moving the plate vertically relative to the knife, the threads on the nuts cooperating with the threads onthe spindles to swing the stonesrelative to the knife.

7. In a cloth-cutting machine of the recipro-.

on the arms, threaded extensions on the spindies, fixed threaded nuts on themachine with which the spindles make threaded engagement when the plate is in its upper position to swing the stones relative to the knife, and means for traversing the plate along the length of the knife and back, the threads on the nuts cooperating with the threads on the spindles to swingthe stones into contact with the knife at the beginning of the downward traverse and out of contact with the knife at the end of the upward traverse.

8. In a cloth-cutting machine of the reciprocating knife type having a presser foot and guard, the combination of stones `for sharpening the knife mounted upon the machine beyond the guard when not in use, means for rotating the stones, means for moving the stones around the guard and into grinding engagement with the knife, means for traversing the stones along the length of the knife and back, means for movingk the stones beyond the guard and into their orig-` power,y and means rendering said manual means inoperative unless the presser foot is in its lowermost position.

9. In a cloth-cutting machine of the reciprocating knife type having a motor for reciprocating the knife and a fly-wheel on the motor, the

-combination of a frame carried by the machine,

on the arms, means for rotating the stones, means y for swinging the arms to bring the stones into grinding engagement with the knife, a drive wheel mounted on the frame mechanism actuated by the drive wheel for rotating the stones, swinging the arms and moving the slide, and means for throwing the drive wheel into driving engagement with the fly-Wheel.

10. In a cloth-cutting machine of the reciprocating knife type having a presser foot mounted on a vertically adjustable' guard, a motor. for reciprocating the knife, and a ily-wheel on the motor, the combination of stones for sharpening the knife, means for traversing the stones along the length of the knife and back. a drive wheel for actuating the traversing means pivotally mounted adjacent the ily-Wheel, a spring and toggle normally holding the drive wheel out of engagement with the fly-wheel, and a manually operated trigger for breaking the toggle to swing the drive wheel into engagement `with the flywheel.

11. In 'a cloth-cutting machine of the reciprocating knife type having a presser foot mounted on a vertically adjustable guard, a motor for reciprocating the knife anda fly-wheel on the motor, the combination of stones for sharpening the knife, means for traversing the stones along the length of the knife and back, a `drive wheel for actuating the traversing means pivotally mounted adjacent the y-wheel, a, spring and toggle normally holding the drive wheel out of engagement with the iy-wheel, a manually operated trigger for breaking vthe toggle to swing the drive wheel into engagement with the flywheel, and a trip movable with the stones for engaging the trigger at the end of the upward traverse of the stones to throw the drive wheel out of engagement with the ily-wheel.

12. In a cloth-cutting machine of the reciprocating knife type, the combination of a frame carried by the machine, a slide slidably mounted in the frame, a pair of swinging arms carried by the lower end of the slide, vstones for sharpening the knife mounted on the arms, means for rotating the stones, means for swinging the arms to bring the stones into grinding engagement with the knife, means for moving the slide relative to the frame to traverse the stones along the length of the knife and back, and a motor mounted on the slide for rotating the stones,swinging the arms, and moving the slide.

13. In a cloth-cuttingmachine of the reciprocating knife type, the combination of a frame carried by the machine, a slide slldably mounted in the frame, a pair of swing arms carried by the lower end of the slide, stones for sharpening the knife mounted onA the arms, means for rotating the stones, means for swinging the arms to bring the stones into grinding engagement with the knife, means for moving the slide relative to the frame to traverse the stones along the length of the knife and back, a pivoted varm carried by the slide and connected with the stone arms, a-roller on the'A upper endof the pivoted arm and a. cam on the frame engaging the roller to swing the vlo stones out of engaaementlwitln the knife at the end oi the nowarci traverse.

i4. In a clotiilontting maschine ofthe reciprocating knife type, tine combination of a frame carried by the machine, a slide slidably mounted in the frame, a pair of swinging arms carried by the lower end of the slide, stones for'sharpening the knife mount-eel on the arms, means for rotaiaing the stones, means for swinging the arms to bring the stones into grinding engagement with the knife, means for moving the slide relative to the frame to traverse the stones along the length of the knife and oaek, a motor mounted on the slide for rotating time stones, swinging the arms. and moving tine slide, a manually operated switch for actuating the motor and means for automatioaliy opening the Saiten at tine endof the upward Y traverse.

i5. In a sloth-entities machine of the reciprocating knife type, having a presser foot and guard, the combination oi a frame pivoted upon the machine, a slide slidably mounted in the frame, swinging arms carried by the slide, stones for 'sharpening the knife carried by the arms, means vfor holding the lower ends of the frame and slide away from the knife when not in use, means for rotating the stones, means for swinging the frame and slide toward the knife, means for swinging the arms to move the stones around the guard and into grinding engagement with the knife, means for traversing the stones along the length oi the knife and back, means for swinging the frame and slide back to their original position i at the end of the grinding cycle, and means for swinging the arms to separate the stones and enable them to pass the guai-ti as the frame and siicie are swung back to original position,

i6. En a olotiientting maoirlne o1' the recinto2 Y eating knife type, the combination oi means for sharpening the miie comprising two stones one V onI either side oi' the knife, one stone comprisins tion of the double stone engaging the miie after the lower nas passed beyond the lower end of the knife.

i7. In e clothmcutting machine oi the reciproeating knife type having agnard, the combination of stones ier sharpening the .knife mounted, when not in use, above the upper end of the knife and beyond the guard, means for rotating the stones,

' means ior swinging the stones around the guard and into grinding engagement with the knife, means 'i'or traversing the stones along.7 the length oi the knife ansi back, and means for swinging the stones around the guard and into their original position at the end of time grinding cycle.

i8. lin a cloth-cnttina machine oi the reciproeating knife type having a guard, the combination oi stones for sharpening the knife mounted.

when. not'in use, above the upper end of the knife' and beyond the guard, means for rotating the stones, means for moving the stones around the guard and into grinding engagement with the knife. means for traversins tne stones along the length oi the knife and back, and means for moving the stones around the anard and into their original position at the end oi the grinding cycle.

' BANGSER..