US2385768A - Sewing machine - Google Patents

Description

Oct. 2, 19.45, H. E. ALTHENS 2,385,768

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SEWING MACHINE v Oct. 2, 1945.

F-led Dec. 24, 1945 3 Sheets-Sheet 2 oct. 2; 1945.

H. E. AL'rHENs l SEWING MACHINE Filed Deo; 24, 1943 1g @im 3 Sheets-Sheet k25 Patented oei. 2, 1945 UNITED STATES PATENT orrica assassinsA SEWING MACHINE nei-bert' a. molens, Newton, Mm., mignon :o 'The Reece Brittonl Hole Machine Company, Boston, Mass., a corporation of Maine Application December 24, 1943, Serial No. 515,538 4`Claims. (Cl. 11B-219) 'wol-k, together with power control or stop mechanism which is separately manually operated (as by a-second treadle) to start the machine and automatically operated to stop the machine upon the completion of a predetermined sewing oper-- ation. However, the invention is equally applicable, at least in part, to other types of sewing machines having separately operated work clamp releasing and starting and stopping devices.

In machines of this general type, it is highly desirable (in order to avoid injury to the needle the work until after the needle has withdrawn from the work in the completion of the last stitchl forming cycle. The invention also has for an object vthe provision of an improved and simplified interlock for this purpose. .l

The foregoing and other objects of the invention, together with means whereby the latter may be carried vinto effect, will best beY understood from the following description fof an illustrative embodiment thereof shown in the accompanying drawings, this, however, having been -chosen forv purposes of exempliiication merely, as it is contemplated that the. invention, as defined by the claims hereunto appended, may be otherwise embodied without departure from itsI spirit and SCOPE.

or the work or both) that the operator be prevented from releasing or lifting the work clamping devices except when the machine is at rest, or about to stop, and with the needle free from the work, and also be prevented from starting the machine unless the work is properly clamped.

Various expedients, in the nature of interlocks between the manually operated work clamping and releasing and starting and stopping devices, designed to accomplish these results, have been proposed, but so far as I am aware none of these have been such as to prevent manual release or lifting of the work clamp during the final stitchformingv cycle of the sewing operation. In all machines of which I am aware, to which such prior expedients have been applied, the power control or stop mechanism is of such a character,

and must be so timed, as to movel into stopping position just after the beginning of the final stitch-forming cycle, during which the needle descends to penetrate the work and thereafter Withdraws therefrom. Consequently, should the operator attempt to anticipate the stopping of the machine, by pressing upon the work clamp re- In said drawings: v g j Fig. 1 is a side elevation, partly broken away and partly in longitudinal section, of a'button sewing machine including an embodiment of the invention, some parts of themachine not pertinent to the invention and not necessary to a full understanding thereof being omitted.

Fig. 2 is a horizontal section taken substantially on the line 2-2, Fig. 1.

Fig. 3 is a fragmentary horizontal section taken substantially on the line 3-3, Fig. 1.

Fig. 4 isa fragmentary vertical section taken substantially on the line l-l, Fig. 2.

Fig. 5 is a view, similar to Fig. 4, showing cer.-

' tain of the parts of the latter figure in a different position.

Fig. 6 is a fragmentary side elevation of parts of the interlocking mechanism shown in Ijig. 1, showing said parts in a different position.

Fig. 7 is a detail view of one member of the v interlocking mechanism.

Figs. 8, 9, y10 and 11 are diagrammatic` viewsy illustratingv the operation.

The invention is herein illustrated as embodied in a button sewing machine similar to that described in the aforesaid Reece patent to which reference may be had for a more complete show- 45 ing of parts not fully shown and described herein.

leasing treadle prior to the completion of the l sewing operation (as frequently occurs), the interlock would be released and the work clamp lifted when the needle was' descending or was engaged with the work. The present invention has for an object to provide a power control mechanism which is so constructed and timed,

0 supported therefrom by an upright housing porand is so inter-related or interlocked with the clamp releasing devices as to prevent release of Referring to Fig. 1, the frame or casing of the machine, which encloses theprincipal parts of the operating and controlling devices, comprises a base or bed 29 and an overhanging head 2i tion 22. The bed 20 carries a work plate 23 upon which is supported the work W to which a button B is to be attached and against which said work.

is clamped during the sewing operation by a presser-foot 24 associated with a buttonv clamp suitably positioned recesses in the wall of the casm ing 28, 29, said main cam is rotated in definite time relation, and at a reduced speed, with respect to the needle shaft. The main cam makes one complete rotation during a plurality but predetermined number of complete rotations of the needle` shaft, each corresponding to a g. The shaft 21 of the'main cam 00 being connected with the lneedle shaft 25 by the worm gear-l stitch-forming cycle during which the needle descends to penetrate the work and thereafter rises therefrom. Consequently, there is a definite portion lof the angular movement of the main cam corresponding to each stitch-forming cycle, and the stud 04 is so positioned, with respect to the portion of angular movement (indicated at a in Fig. 3) corresponding to thenal stitch-form.- ing cycle of the complete predetermined sewing operation, as to engage and operate the bunter 52 just prior to the completion of said final stitchforming cycle. Also, the dog 55 is so angularly positioned on the hub 1|, and consequently on the shaft 25, with respect to the angular- 4positioning of the crank 30 (or equivalent needle bar actuating means) on said shaft,.that the stop finger 14 approaches the plane of movement of the head 15 of the stop arm 11 (as shown in Fig. 4), and engages said head to stop the machine (as shown in Fig. 5), if the stop arm is in stopping position, just prior to the completion of each stitch-forming cycle and after the needle has risen or been withdrawn from the work.

The relative timing of the parts is diagrammatically illustrated in Figs. 8 to 1,1. In Fig. 8, the final stitch-forming cycle has been a little lmore than half completed; the needle 35 is in the work W, has reached its lowermost position,

and has started to rise therefrom; the stud 04 has not yet engaged the bunter 02', so that the stop larm 1l is still in running position with its head 15 out-of the path of movement of the stop finger 14; and the dog 00 is engaged with the shoulder I, thereby coupling the pulley 25 to the needle shaft 25. In Fig. 9, the needle has risen far enough to disengage or be withdrawn from the work but is still in proximity thereto, the stud 84 has been brought into engagement with the inclined end 93 of the bunter but has not yet moved the latter, so that the stop arm is still in running position and the pulley 25 remains coupled to the needle shaft. In Fig. 10, the needle, now completely withdr-awn from the work, is approaching its uppermost position, the stud 04 vhas moved the bunter 02 far enough to swing the stop arm 11 into stopping position with its head 15 in the path of movement of the stop finger 14 which has reached an angular position where it is about to engage said head. In Fig. 11, the needle has reached its uppermost position remote from the work, and the stop finger 14 has engaged the head of the .Stop arm, thereby disengaging the dog 69 from the shoulder 50, uncoupling the pulley 26 from the Vneedle shaft and positively stopping the latter. It will therefore be seen that the stop arm (together with the rock shaft 04 and arm remains in running position until the needle has been completely withdrawn from the work at substantially the completion of the final stitch-forming cycle, and that when the stop arm is then moved into. stopping position the machine is almost immediately stopped with the needle still remote from the work.

In order to .prevent lifting of the presser-foot 24, -by the treadle, to release the work, except when the machine is at rest, or is about to stop, with the needle disengaged from the work, and to prevent movement of the stop arm. 'l1 into running position, by the treadle 01, to start the machine, except when the work is properly clamped to the work plate by the presser-foot, the interlock mechanism best shown in Figs. 1, 2, 6 and 'l is provided. The latch lever 52, whosepivot is directly below the free end of the operating arm 05 to which the link 88 is attached, is in the form of a bell crank lever having, in addition to the arm 5 3, a second arm |0| which extends upwardly toward the arm 05. The arm |0| is formed with an-upper arcuate edge portion |02 concentric with the axis of the pivot 59 and underlying a pin |03 extending laterally from the arm 05, said edge. portion terminating in a notch |04 adapted to receive said pin. Turning of the lever 52 on its pivot 50 in a counter-clockwise direction, under the influence of the springs 40 and 50, is limited by engagement of the arm |0| with a pin |05 projecting from the casing wall, and when said arm is in engagement with said pin the notch |04 is directly opposite the pin |03. Otherwise, the arcuate edge portion |02 is of sumcient length to underlie the pin |03 throughout the range of lifting movement of the presser-foot by the treadle 50.

When the machine is at rest, with the stop arm 11 and operating arm 05 in the stopping position shown in broken lines in Fig. l, the pin |03 is free from the notch 04, and the presserfoot 24 can be lifted by depression of the treadle 50. When this is done, the arcuate edge |02 of the arm |0| of the latch lever 52 passes under the pin |00, as shown in Fig. 6, thereby blocking downward movement of the arm 85. Consequently, so long as the presser-foot remains lifted, and thework is unclamped, the arm `85 cannot be operated by the treadle 01 to move the stop arm `11 into running position, shown in full lines in Fig. 1. When the treadle 50 is released, permitting the spring 40 to restore the presserfoot to work-clamping position,l the latch lever 52 moves into the position shown in Fig, 1, carrying the arcuate edge |02 out of blocking relation to the pin |03 and bringing the notch |04 opposite said pin. The treadle 81 can then be4 freely depressed to move the stop arm into running position,`shown in full lines in Fig. 1, to start the machine. When this is done,`the pin |03 enters the notch |04, thereby locking the lever 52 against. clockwise-movement and preventing deuntil it is moved into stopping position, shown in pression ofthe treadle 58 to lift the presser-foot and release the work. This condition exists so long as the stop arm is in running position and broken lines in Fig. 1, to stop the machine. As above explained, thisdoes not occur 'until the final stitch-forming cycle has been nearly completed and the needle fully'retracted from the stopped, so that the needle cannot again descend into engagement with the work.

' I claim:

1. In a sewing machine having work clamping means, in combination| manually operated means for starting said machine, other manually operated means for releasing said clamping means,

and means for preventing the concurrent operation oi said manually operated means comprising a pivotally mounted latch having a notched arm adapted to prevent the operation of said starting means except when said notch is in position to receive an element of said starting means and having a lever arm connected with an element of said clamp releasing means, said arms having a relative position such that any movement of said lever arm in response to actuation by said releasing means serves to move said notched arm into a position in which said notch is thrown out of receiving position. y

2. In a sewing machine having work clamping means, in combination, manually operated means for starting said machine, other manually operated means for releasing said clamping means, and means for preventing the concurrent operation of said manually operated means comprising a pivotally mounted latch having a notched arm associated with said starting means and a lever arm connected to an element of said releasing means, said notched arm being adaptedto prevent said starting means fromassuming 'starting position except when an element thereof is in line with said notch, the reception of said element into said notch acting to lock said latch against pivotal movement and thereby to prevent operation of said releasing means while said starting meansjis in operation. I

`3. In a sewing machine having work clamping means, in combination, manually operated means ior starting said machine, other manually operated means for releasing said clamping means, and means for preventing the concurrent operation of said manually operated means comprising a pivotally mounted latch having one arm with an arcuate edge concentric with the axis ot said -latch adapted to maintain a. constant predetermined distance between said axis and an element associated with said starting means, a notch formed in said edge adapted to receive said element so as to permitsaidstarting means to assume starting positiornand a second armI connecd to an element of said releasing means adapted on the operation oi' said means to turn said latch to move said notch out of receiving po sition and to move said arcuate edge into a position opposite the element associated with the starting means so that said starting means is locked ini inoperative position during the operation of saidreleasing means.

4. In a sewing machine having work clamping means, in combination, manually operated means tor starting said machine, other manually operated means for .releasing the clamping means, and means for preventing the concurrent operation of both manually operated means comprising a pivotally mounted latch having one arm with an arcuate edge concentric with the axis of the latch adapted to maintain a constant predetermined distance between the axis and an element associated with the starting means, a notch formed in said edge adapted to receive said element when the starting means is in starting position, and a second arm connected to a member oi' the releasing means, the reception ci' the element of said starting means into the notch acting to lock the latch against pivotal movement so that the second arm connected to an element

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