US2444909A - Cloth-cutting machine - Google Patents

Description

July 13, 1948. w. BANG S ER CLOTH-CUTTING MACHINE 5 Sheets-Sheet 1 Filed July 4, 1945 INVEN Mlam ZOR ,2 ATTORNEYS y 1948- w. BANGSER 2,444,909

I CLOTH-CUTTING MACHINE Filed July 4, 1945 3 Sheets-Sheet 2 ATTORNEYS W. BANGSER CLOTH-CUTTING MACHINE July 13-, 1948.

s Sheets-Shee't :s

Filed July 4, 1945 E C')R Mai?- M431 film ATTORNEYS Patented July 13, 1948 2,444,909 CLOTH-CUTTING-MAGHINE =William Bangser,- New York,N. Y., .assignorl-ito H. Maimin Company, Incorporated, acorpora- .tion of New Yor Application July 4, 1945, Serial No; 603,153

2 Claims. 1

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

In my Patent-No. 2,156,798, I have illustrated and described a motor-drivencloth-cutting ma chine of the reciprocating knife type provided with a pair of rotary grindstones for periodically sharpening the knife. 'Whilethe machine is being used for cutting cloth, the stones, carried on swinging arms, mounted in a vertically reciprocating slide-are held forward of the knifeguard, well above and beyond the upper end .of the knife. When the time for sharpening comes, the guard and presser footare lowered and a friction drive wheel isswung into contact with thefly wheel of the motor, whereupon, through appropriate mechanism the stones, rotating on vertical axes, are swung on'their arms around the guard and into'grinding contact with the knife, one on either side. While the stones are still rotating (outwardly with respect to the cutting edge) the slide on which-they are'mounted is moved down the length of the reciprocating knife and up again, whereupon the stones are swung out by the same means that swung them in, and into inoperative position; thus completing the grinding cycle.

. This machine has performed its intended func-' tion'efficiently and well. Under certain circumstances, howeventhe operation has been found to be less than perfect, and it is the object of the present invention-to eliminate these imperfections.

The means shown in my patent for swinging the stones into and out of grinding contact with the knife comprises spindles about which the stonerarms'swing, movable with the stones :and' provided with threads of large pitch which engage nuts-of like pitch fixed to the frame of-thema-' chine. It has been found that, under the vibra-' tion ofoperation, a stone may swing slightly out of its proper position toward the end of the grinding cycle so that the upper end of its threaded spindle-engages its nut with the threads out *of alinement. This immediately jams the machine. In accordance with the present invention I have provided helical cams of such configuration that no matter how far out of position a stone may vibrate-ewithin the limits imposed by the machine itself-the fixed and movable cams will cooperate to swingthe stone to its prearranged position of rest without possibility of jamming.

It has also been found that the grinding mechanism, under the vibrations set up by the clothcutting operation, has a tendency to creep. This 2 is because, when'the friction drive wheel ismoved out ofcontact withthe fly wheel at the end -.ofv the grinding cycle, the movement of i the grinding mechanism stops instantly, leaving only a-very small clearance betweenxthe-two Wheels. The grinding cycle cannot be initiated-while the presser :foot iselevated above the base of thermachine-because. a safety arm, swingable-with the friction drive-wheel,- engages the guard when the presser foot is elevated andso prevents therdrive wheel fromimaking driving'engagement with-the rotating fly wheel. As the presser foot and guard are-always raised during cloth-cutting, creeping of the grinding mechanism cannot. accidentally initiate thegrindingcycle at that time nevertheless, thislcreepi-ng causes the-safety arm to press against-the guard and binds it in' its guideways so that i-tcannot be raised and lowered as it-free quently must be in norm-alpoperation, In accordance with the present invention, I have provided means for-positively. latching the reciprocating grinderislide" in its upper or inoperative position so: thatv the mechanism: cannot creep farenough to bind'theguard.

r Inthe accompanying :drawings I have illustrated certain preferred embodiments -of-my invention although otherscould doubtless-be =devised within its purview, as defined by the 'appendedclaims... In these drawings,

Figure 1 is a side elevation of a cloth-cutting machine ofthe reciprocating knife type,

Figure 2-is a fragmentary-vertical section on an enlargedscale taken along line 2--2 of Figure 1,

- Figure 3 is avertical section taken along line 3'--3 of-Flgure 4, I 1

Figure 4:iS a vertical section taken along .line 4-4 of Figure 3,

"Figure 5 is a fragmentary front elevation showing thegrinder slide latch,

Figure 6 is a horizontal section taken along line 6----@ of Figure 5,

v-"Fi ure '7. issan end view 'of the latch'shown in Figure5,

.-Figures 8, 9, 10 and 11 are perspective =views of the? right hand helical cams, and

Figures 12 and 13 aretransverse sections taken along lines 12 and 13 respectively.

Except for the helical cams and the grinder slide-latch of the present invention-and the gear shift mechanism, the-machine illustrated in these drawings is essentially the one illustrated in'Figures 1 through 9of Patent No. 2,156,798, to which the'reader should-refer-for amore detailed account ofthemachineand itspperati ri, a now}- edge of which will be generally presumed in the description to follow.

The cloth-cutting machine illustrated in these drawings comprises the usual base I on which is mounted a standard 2 carrying a motor 3. A knife 4 is mounted in a vertical slot in the forward edge of the standard and reciprocated by means of a cross-head 5, a pitman 6 and a crank I, mounted on the fly wheel 8 of the motor. A guard 9 carrying a presser foot H is mounted for vertical adjustment immediately in front of the knife. Mounted on the front of the motor housing is a fixed grinder frame I 2 having vertical guideways 13 in which is slidably mounted a grinder slide l4 closed at its lower end by a block l extending inward. Journalled in the inner end of this block are two vertical spindles I6 supporting at their lower ends arms l1 carry- I ing studs I8 on which grindstones l9 are journalled. The upper ends of the spindles l6 terminate in pilot rods 21 enveloped by and carrying cams 22 adapted to engage fixed cams 23 carried by the fixed grinder frame I2 to swing the stones l8 into and out of grinding contact with the knife as the grinder slide is traversed, substantially as described in Patent No. 2,156,798. Coil springs 24 encircle the cams 22, being anchored at one end to the block 15 and at the other to one of the earns 22, and tend to swing the stones into grinding contact with the knife.

The shaft 25, which carries the friction drive wheel 26, is journalled in a sleeve 21 pivoted at 28 to the fixed grinder frame l2 for movement of the drive wheel in a vertical plane and is also journaled at the end remote from the drive wheel in a block 29 likewise pivoted at 28 to the frame. A trigger arm 30 is pivoted at 3! to the lower face of the block 29 for movement in a horizontal plane. During the cloth-cutting operations of the machine the trigger arm 30 is held in a horizontal position parallel with the grinder slide [4 by means of a bracket 32' projecting from the forward face of the slide and in this position, as illustrated in Figure 5, the friction drive wheel 26 is held'out of contact with the fiy wheel 8. A coil spring 33, supported at one end upon a bracket 34, which extends laterally from the fixed grinder frame [2, engages the pivoted block 29 at its other end, and tends to swing the block clockwise about the pivot 28 to hold the friction drive wheel 26 in driving engagement with the fiy wheel 8. As long, however, as the trigger arm 30 is held in horizontal position by the bracket 32, the spring 33 is held under compression and cannot act to swing the friction drive wheel into driving position. In order to initiate the grinding cycle, the operator seizes the trigger arm 30 and swings it forward about its pivot 3| against the compression of a spring 35 which normally holds the trigger parallel to the grinder head l4. When the trigger has cleared the bracket 32, the spring 33 is free to act and does act to swing the friction drive wheel into engagement with the fiy wheel. At the same time a cam 38 depending from the trigger arm 30 withdraws a slide latch 36 from an opening 31 in the grinder slide 14 where it is normally held under pressure of a spring 40, and this frees the slide for the grinding traverse, which immediately follows.

At the end of the shaft 25 remote from the friction drive wheel 26 there is fixed a pinion 39 which meshes with a gear 4| coaxial with a pinion 42 meshing with a gear 43 which, in turn, drives a pinion 44 meshing with a gear 45 integral with a bevelled pinion 46 which drives a second bevelled pinion 41 through which passes a vertical square drive shaft 48 journalled in the grinder slide l4. Fixed to the lower end of the square shaft 48 and just below the lower face of the block I5 is a gear 49 which meshes with a pinion 5| coaxial with the spindle I6 which pinion in turn meshes with a gear 52 carried by one of the grindstones l9. A similar gear train rotates the other grindstone through the intermediary of an idler 53 mounted on the lower face of the block l5. When friction drive wheel 26 is swung into engagement with the rotating fly wheel 8 of the motor, the gear trains described above are-set into operation to rotate the grindstones l9. The gears 36 through 41 are mounted upon the fixed grinder frame l2, whereas the gears 49 through 52 and 53 are carried by the grinder slide l4 and move with it. The square shaft 48 which makes a sliding engagement with the bevelled pinion 41 and extends the entire length of the grinder slide 14, drives the second gear train throughout the grinding traverse and in all positions of the grinder slide.

The grinder slide M is traversed as follows:' Two sprockets 15 are mounted upon the grinder frame 12 and about these runs a chain'lli, one link of which carries a roller 11 lying within a horizontal slot "I8 in a plate 19 fixed to the upper end of the grinder slide 14. Movement of chain 16, therefore, reciprocates the slide. The chain is driven through a pinion 8| fixed to gear 43 and meshing with a gear 82 and the lower sprocket shaft. The pinion 44 is rotatably mounted on a spindle 54 carried by a link 55 mounted for limited oscillation about'a spindle 56 onwhich the combination spur and bevelled gears 45, 46 are journalled and made to mesh either with driving gears 43 or 53, the latter carried by gear 61 which, in turn, is'driven by gear 4|. A gear shift lever 62 is pivotally connected at its inner end to spindle 54, which carries the pinion 44, so' that the operator, by seizing the knurled end of the shift lever and properly manipulating it, may

i move the pinion 44 from the low speed position shown, where it meshes with gear 43 to' the high speed position where it meshes with pinion 59. In this way the rotary speeds of the stones may be varied. As this gear shift forms no part of the present invention, I shall not describe it further.

The cams 22 and 23, as shown most partic-' ularly in Figures 8 through 13, are so designed that no matter how far the movable cam 22- may be displacedwithin the limits imposed by the machineit will always engage the fixed cam 23 V in such a way as to swing its stone into its proper positionof rest. The helical cams of each engaging pair are complementary, being semicylindrical at their bases and tapering toward their outer ends. The rear faces of both cams are provided with bulges 22a and 23a respectively which act to guide the cam 22 back into proper engagement with cam 23 should the former, by any chance, swing too far out of line. The cams can thus operatively engage through a wide arc of displacement.

Fixed to the sleeve 2'! in which the shaft 25 of the friction drive wheel 26 is journalled, is an arm 84 pivoted at 28 and extending upwardly and inwardly, as illustrated in Figures 2 and 5, terminating in a set screw 85. This safety arm 84 lies within the vertical plane of the presser foot guard 9. When the friction drive wheel 26 is in its inoperative position, as shown in the drawings, set screw 85 is out of engagement with the presser foot. When, however, the drive wheel 26 is swung toward engagement with the fly wheel, the set screw 85 would engage the guard if in elevated position, and thus prevent driving contact being made. It is, therefore, necessary for the operator first to lower the presser foot so as to carry the upper end of the guard below the are described by the set screw 85. As explained above, however, the mechanism has a tendency to creep. If not prevented by the latch 36, this creeping motion would bring the set screw 85 into engagement with the elevated guard and exert sufiicient pressure to bind and prevent manipulation of it by the operator.

I shall now describe briefly the operation of the machine throughout one grinding cycle. The operator first lowers the presser foot to move the guard below the are described by the set screw on the safety arm 8 and an appropriate switch is closed to set the motor in operation. The operator then seizes the trigger arm 30 and pulls it forward out of engagement with the bracket at 32; whereupon the spring 33 swings the friction wheel 28 into engagement with the fly wheel 8, the cam 38 withdraws the latch 36 from the hole 37 in the slide it which immediately begins its downward movement while the grindstones 19 are swung around the guard and into grinding engagement with the knife due to the action of the springs 24 and the cams 22 and 23. On the return movement as the slide approaches the upper end of its traverse, the pilot rods 21 are received by the fixed cams 23 and guide the lower cams 22 into engagement therewith. Further upward movement of the slide, therefore, causes the spindles it to swing so as to carry the grindstones l9 around the guard and into inoperative position. Toward the end of the return movement of the slide, the bracket 32 engages the trigger arm 38, which has been swung inward by spring 35, and moves it into horizontal position against the pressure of spring 83. This swings the friction drive wheel out of engagement with the fly wheel and at the same time raises cam 88 permitting the spring 48 to swing the latch 35 back into the hole 37 to latch the slide as it reaches its upper position, thus ending the grinding cycle.

I claim:

1. In a cloth-cutting machine of the reciprocating knife type, the combination of a slide movable relative to the knife, a pair of spindles carried by the slide and terminating at their upper ends in pilot rods, swinging arms fixed to the spindles, stones for sharpening the knife mounted on the arms, a helical cam carried by each pilot rod, fixed helical cams on the machine adapted to receive the pilot rods and with which the movable helical cams engage when the slide is at or near its upper position, the helical cams of each pair being complementary, semi-cylindrical at their bases, tapering toward their outer ends, and with guiding bulges on their rear faces whereby they may operatively engage through a wide arc and means for moving the slide vertically relative to the knife, whereby engagement of the fixed and movable cams swing the stones relative to the knife.

2. In a cloth-cutting machine of the reciprocating knife type, the combination of a slide movable relative to the knife, a pair of spindles carried by the slide, swinging arms fixed to the spindles, stones for sharpening the knife mounted On the arms, a helical cam carried by each spindle, fixed helical cams on the machine with which the movable helical cams engage when the slide is at or near its upper position, the helical cams of each engaging pair being complementary, semi-cylindrical at their bases ta-- pering toward their outer ends, and with guid ing bulges on the rear faces and means for moving the slide vertically relative to the knife,

" whereby engagement of the fixed and movable cams swing the stones relative to the knife.

WILLIAM BANGSER.

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

UNITED STATES PATENTS Number Name Date 40 1,173,983 Perlman Feb. 29, 1916 1,815,017 Wagner July 1 1, 1931 1,815,018 Wagner July 14, 1931 2,156,798 Bangser May 2, 1939

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