US2275667A - Shoe stitcher - Google Patents

Description

March 10, 1942. E WOLF 2,275,667

SHOE STITCHER Filed Feb. 26, 1940; 2 sheets-sheet 1 I r l INVENTOR u EUGENE G. WOLF ATTORNEY March 10, 1942} EQG. WO LF- r SHOE STII-CHER Filed Fb. 26, 1940 2 Sheeis-Sheef'Z INVENTOR EUGENE G. WOLF I ATTORNEY Patented Mar. 10, 1942 snoa s'rrrcmut Eugene G. Wolf, St.

Louis, Mo., assignor to Landis Machine Company, St. Louis, Mo., a corporation ofMissouri Application February 26, 1940, Serial No. 320,845

90mins. The invention relates to sewing. machines; and more particularly to machines for stitching leather; and the. present drawings illustrate and thespecificaticn describes. a machine of thewellknown Goodyear type adapted for stitching shoe soles and. uppers together and equipped with the present invention.

Institchers of the class referred to, the thread passes from the spool through atension device, then through a threadmeasuring device, then througha thread lock, then over an auxiliary take-up: device, then over a main take-up device, and then to the thread .looper which; lays the thread around the needle to be. drawn through the work. During each cycle of operations the thread measurer draws through the thread tension (the thread lock being set) sufiicient thread for-the next stitch. Also during each cycle of operations, the main take-up moves towards the work togive up slack sothe needle may draw the thread through the: work. without undue tension. Thereafter the main take-up moves in theopp0- site direction to pull on the thread and. tighten the stitch just formed and also to pull through the thread lock (temporarily released) the supply ofthread for the next stitch which supply the thread measurer has just drawn through the tension device. While the main take-up is giving up slack, it is necessary to provide some tension on the thread to hold it to the thread hook and the; looper and prevent the thread loop from being so loose as to he unmanageable. The auxiliary take-up is provided for this purpose and may consist of a spring mounted roller over which the. thread passes on its way from the thread lock to the main take-up device.

Throughout all of a sewing operation, except during the initial stitching, thereis a portion of each cycle of the machine: during which. the thread lock is set, and the machin presser foot and the work support clamp the work and the previously set stitches, and the auxiliary take-up takesup the slack inthe stretch of thread between the work and the thread lock. Then, when the main take-up functions, the thread tensioned thereby first pulls the auxiliary take up to a jfixed, stop-engaging position and then pulls the stitch-forming portion of the thread against thework to tighten the stitch. Then, as the main take-up gives up slack, it releases the auxiliary take-up which is moved. by its spring to maintain the desired reduced tension upon. the thread so that the thread will be :held against the thread hook and the barb oi the needle.

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But at the beginning of a sewing operation, and prlor to the insertion of the work into the machine, the operator manually rotates the main shaft by its hand wheel to place the main takeup in a position where its initial movement, after the machine is started, will. be to give up slack. In so setting the main take up, there is no great tension: on the threadand the auxiliary take-up spring is not distorted and hence the auxiliary take-up is projected to the end of its ordinary take-up movement. Hence, whenthe'machinestarts to stitch and the main take-up moves up to give up slack, the auxiliary take-up does not immediately perform its normal function of keepme the thread taut between the thread lock and the needle and there is a surplus of thread at the work. This surplus is not reduced by the initial downward movement of the main take-up because the thread measurer has supply as much thread as is necessary for a complete stitch and this supply is added to the original length of thread between the thread lock and the work. The. initial surplus is absorbed by the cumulative looseness of the first few stitches but it is only thereafter that the auxiliary take-up is pulled down and is spring actuated to maintain the thread taut as intended. 3

As a result, the thread near the hook and needle may be slack throughout the first few stitching operations and the first few stitches will not be set tightly in the work but will stand out from the work, presenting an unsightly appearance.

The main object of the present invention is to avoid this inefiective setting of the first few stitches of each sewing operation.

This object has been attained in previous machines by the use of a cam andlever for positively holding the auxiliary take-up from maximum take-up position during the initial action of the machine. This requires additional mechanism. in the restricted space available for the necessary cams, levers, etc.

It is a further object of the present invention to control the auxiliary take-up as described above by a simple connection to another part of the mechanism, such as the thread measurer, for example, which will function without requiring a separate cam and lever arrangement which adds to the complexity of the mechanism and increases the difficulty of access to adjacent parts.

These objectives are attained by the structure illustrated in the accompanying drawings in which- Figure 1 is a side elevation of a stitcher' of the class describedequipped with the present invenfunctioned. to a with upright standards 3 journalling the main cam shaft 4. The main take-up cam groove 5 lever 1 pivoted at 8 and connected at its opposite end 9 by alink- ID to the short arm ll ofa bell crank pivoted receives a roller 6 on one end of a at l2, the opposite end of the other arm l3 of the bell crank forming them ain take-up arm a which carries the roller I4.

The thread measurer cam groove 15 receives -a 1 roller I6 on the end of the arm ll of a bell crank pivoted 'at'l8 and having a depending arm l9 connected by a link'26 to a slide 2| pivoted at 22 to a harp-like frame 23 which is connected at 24 to the presser foot lever'25, whereby the height of frame 23 is controlled by the height of the presser foot 31. Variations in the height of frame 23 vary the height of slide pivotv 22and this varies the throw of a block 26 slidablefin slide 2I- and connected toan arm 2'! on a shaft 28 which also mounts an arm 29 carrying a grooved thread measuring roller 30.

up arm l3 and this is the position to which the main take-up arm must be moved by the operator when he begins a sewing operation. Hence, it is obvious that because of hook 50 the auxiliary take-up actuating spring 43 cannot move auxiliary take-up arm 40 upwardly at such a time.

When the operator begins a sewing operation, he depresses a foot treadle to raise presser foot 31 and rotates the main shaft by the hand wheel until the main take-up is in its lowermost position. Thread lock 3| and thread tension 33 are released by the same treadle movement which released the presser foot and the operator draws it thread freely through the machine to overlie the work support 36.

. The operator then inserts the work between thepresser foot and work support 36 and in line with the path of the needle and awl. The operator then releases the treadle, per- In each cycle or operations of the machine,

roller 36 is raised from the position shown in Figure 1' to that shown in Figure 2, the exact extent of the rise depending upon the height'of frame 23 as determined by the thickness of the work between the work support 36 and the presser foot 31.

A threadlocking lever 3| is timed to press against the thread on a stationary guide roller 32 when thread measuring roller is moved upwardly, whereby roller 39 draws thread through a thread tension device 33 from the supply spool (not shown) and not from the portion of thread extending from roller 30 to the work. Locking lever 3| is actuated by a crank 34 on a shaft 35 which is oscillated by a cam (not shown) in the usual manner. a

All of the above described main take-up, thread feeding and thread measuring devices are well known and in themselves do not constitute the present invention.

An auxiliary take-up arm 46 is pivoted on the machine frame at 4| and carries a roller 42 at its outer end. A spring 43 has its left hand end held down by the thread lock crank shaft 35 and passes over a grooved roller 52 on the thread measurer crank shaft 28 andbeneath a stud 45 at the outer end of auxiliary take-up arm 49.

The spring tends to thrust arm 46 upwardly to the position shown in Figure 2 but thread measurer arm 29 carries a hook 5|] overlying spring 43 and when arm 29 is moved downwardly by the action of cam IE on bell crank |'|--I9, hook 59 engages spring43 and holds it to the position shown in Figure l.

Thread T passes from lock roller 32 over auxiliary take-up roller 42, then over roller l4 on main take-up arm l3, then up to the thread looper 5| and then to the thread hook 46. The needle 41 engages the thread between looper 5| and hook 46 in the usual manner.

Bell crank l1-I9 moves thread measuring arm 29, and hook 50, downwardly during the lowermost inch or so of the travel of -main takemitting the presser foot to clamp the work and the thread together and to the work support and also permitting the thread lock to set.

Then the machine is started and the main take-up moves upwardly from the position shown in Figure 2 to give up slack; and the thread measurer roll 30, behind the closed thread lock, is raised by cam I5, crank l'|-l9, link 20, arm 21, crank 28 and arm 29 to measureoff additional thread for the next stitchf Upon the subsequent downward movement of the main take-up, the thread lock is released and the additional thread just measured is added to the length of thread between the thread lock and the work, and the surplus thread, due to the initial giving up slack by the main take-up, still exists except insofar as it had been decreased'by the looseness of the initial stitch.

But withthe present structure, at the time the operator rotated the main shaft by the hand wheel to place the main take-up in down position, hook 50 held down the auxiliary take-up spring during the clamping" of the work and the setting of the thread lock (bythe release of the treadle) {and the subsequent movement upwardly of hook 50 and the ensuing actionof the auxiliary take-up spring permits the latter to move auxiliary take-up roll 42 to take up surplus thread resulting from the giving up of slack by the main take-up. Hence the initial stitch is taut. Hence the first few stitches of each sewing operation will be drawn as tightly as any subsequent stitches;

" While the auxiliary take-up 46-42 will be held down by hook 50 during a portion of each subsequent stitch, as during portions of the initial stitches as just described, this holding down will not affect the operation of themachine and the action of hook 50 will be immaterial until the next sewing operation is begun;

The present invention is characterized by the temporary interruption of the pull of the auxiliary take-up on the thread leading to the needle during a restricted portion of the cycle of operation of the machine, thereby making it possible for the auxiliary take-up to function effectively immediately subsequent to said cycle portion, which it could not do during the first few stitches of each sewing operation except for the restraint, by means other than the pull of the thread,.on the auxiliary take-up roller. Preferably, but not necessarily, the restraint is of a positive nature and is exerted by a thread manipulating device of the machine, thereby eliminatingthe necessity of additional cams, followers,"levers and connections. t

The details of the device may'be varied without departing from the spirit of the invention and the exclusive use of such modifications as come within the scope of the claims is contemplated.

.What is claimed is:

1. In a stitching machine of the class de-- scribed, a main take-up, a thread measurer, and

an auxiliary take-up device including a spring thrusting the thread engaging portion of the auxiliary take-up device in one direction, there being a connection between said thread measurer and said device for checking the action of said spring during a portion only of the cycle of operation of said thread measurer.

2. In a stitching machine of the class described, a main take-up, a thread lock, a thread measurer, means for setting said lock as said measurer draws thread from the supply and for releasing said lock when said measurer gives up the thread it has so drawn, an auxiliary take-up, and means for holding said auxiliary take-up against tensioning the thread when said thread measurer gives up thread.

3. In a stitching machine of the class described, a main take-up moving to give up slack to the needle, an auxiliary take-up moving to keep the thread taut against the needle as said main take-up gives up slack, and a thread measurer moving to draw thread from a supply as said main and auxiliary take-ups move as described and then moving to yield the thread so drawn to said main take-up and simultaneously moving said auxiliary take-up to non-functioning position- 4. In a stitching machine of the class described, a main take-up, a thread measurer, and an auxiliary take-up device including a spring thrusting the thread engaging portion of the auxiliary take-up device in one direction, said spring extending past a portion of saidthread measurer and being engaged by an element on said thread measurer duringa portion of the cycle of operation of said thread measurer so as. to prevent said auxiliary take-up device from functioning.

5. In a stitching machine of the class described, a main take-up, a thread measuring device ineluding an oscillating shaft and an arm thereon the outer end of which reciprocates to measure the thread, a thread lock includingan oscillating shaft adjacent to said thread measuring device shaft, and an auxiliary take-up including a leaf spring having one end underlying said thread lock shaft and its intermediate portion overlying said thread measuring device shaft and thereby being distortedand its outer end moving the thread engaging portion of the auxiliary take-up, there being a hook on a reciprocating portion of the thread measurer for distorting said spring and rendering the same ineffective during a portion of the stitching cycle.

6. In a stitching machine of the class described, a thread tension device, a thread look, a main take-up, an auxiliary take up engaging the thread between said main take-up and said lock, and

a thread manipulating device between said thread tension device and said thread lock and controlling the operation of said auxiliary take-up.

7. In a stitching machine of the class described, a main take-up, an auxiliary take-up, and a thread drawing device including an element engaging said auxiliary take-up, when said device is moved in one direction, to render said auxiliary take-up inoperative during a portion only of the cycle of operation of the machine.

8. In a stitching machine of the class described, a thread main take-up, a thread auxiliary takeup device including a thread-engaging element and an actuating spring therefor functioning to keep the thread taut, a thread pulling device moved positively in one direction and including an element movable therewith and engaging said device to hold its spring against action during,

a portion only of the cycle of operation of the machine.

9. In a stitching machine of the class described, a main take-up, an auxiliary take-up, a thread measurer and an element movable with said measurer as the latter releases thread to the take-ups to temporarily render said auxiliary take-up inoperative.

EUGENE G. WOLF.

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