US2138939A - Bobbin-case controlling device - Google Patents

Description

Dec. 6, 1938. H, PUDELKQ 2,138,939

BOBBIN CASE CONTROLLING DEVICE Filed Sept. 24, 1954 Patented Dec. 6, 1938 r 2,133,939: 1 BoBBiN CasE con'rnoiltnvo evice f'applicatio'n September 24, 1

7 34, Serial No. 745,184

In Germany Septenfber 30,1933 1 2 Claims." (01. 112 -228) This invention relates to the arrangement of the bobbin case on sewing machines, especially on button hole sewing machines.

The loop-taker, which'as is known serves for guiding the thread, was hitherto arranged in button hole sewing machines in such a manner that the case accommodating the loop-taker was secured on the bed of the machine by two or more screws. If loop-takers were hithertoemployed on button hole sewing machines, these were slipped over the loop-taker shaft by means of a holding journal constructed as a sleeve and secured in position by set screws. This construction is, however, open to the great objection that, in the event of it being necessary to remove the loop-taker for the purpose of cleaning, repairing or the like, it is extremely difficult to again fit the loop-taker so that it is in as accurate correspondence of position with the needle position is essential for the correct working of a button hole sewing machine. This correct adjusting, a fraction of a millimetre being a determining factor therefor, can, however, be carried out in the known arrangement only by special sewing machine experts, so that great delays occur frequently by the calling in of an expert.

As the known bobbin-case tends to participate in the rotary movement of the loop-taker and must therefore be held tightly, it is constructed so that its two abutments bear alternately at one side against a counterabutment fixed-one. rocking escapement yoke or at some other point and on the other side against a counterabutment swinging out periodically, and in'this manner is certainly held securely and nevertheless allows the alternate slipping through of the thread loop.

As only one counterabutment is capable of swinging outwards, this must travel along a very long path'during its swinging out movement, which is only possible owing to a correspondingly high speed, and the bobbin-case likewise has too much play for turning.

As compared with this known construction, the invention consists in arranging a loop-taker on a button hole sewing machine in such a manner that the person operating the machine can remove and replace the loop-taker without any difllculty and without special adjustment, the bobbin-case being provided .with a two-armed rocking escapement yoke, the two counterabutments of which need only to travel a short distance and can therefore be. moved at a relatively low speed.

ing in which the correspond j ing position relative to the position of the needle, the loop-taker- This object is attained according tothe invention in that the loop-taker engages, by means of a guide in its journal coupled with thelooptaker shaft, with a counterguide on the looptaker shaft for the purpose of determining the proper adjustment relatively to the position of the needle, and in that a two-armed pivotally mounted holder is provided with abutments which bear alternately against the corresponding counterabutments of the bobbin-case.

An embodiment of the invention is illustrated by way of example in the Fig. 1 shows the controlling device in side elevation, partly in section.

ing shaft of the button hole sewing machine.

The front end of the loop-taker shaft I is, ac-

accompanying drawcording to the invention, provided with a sleeve 4. A plug 5 inserted in this sleeve 4 has a trans-' verse slot 6. The plug 5 is secured against rotation in sleeve 4 by means of a pin I or the like. The sleeve 4 and plug 5 may evidently be made inone' piece. A journal 9 of the loop-taker has projections 8 which engage in the slot 6 and operatively connect the plug and journal. The

, journal 9 is secured against shifting in axial direction by means of one or several screws I0.

' Instead oil the projections engaging in the slot 6 the arrangement may be such, that a pin,

bolt or the like extending transversely through i the loop-taker shaft constructed as a sleeve, engages in a guide groove in the journal in the sleeve or that the coupling is effected by means of a key and groove.

The bobbin-case 2 is provided with two abutments I I and I2 which prevent its rotation. Two counterabutments l3 and I4 on a two-armed escapement yoke I5 alternately hear against the two abutments II and I2. This escapement yoke I5 is fixed on an axle I6 which is actuated from the shaft I through the intermediary of a cam I1 and a rocker lever I8. The rocking movement of the lever I8 produced by the cam I1 is transmitted to the escapement yoke which conmachine or the loop-taker thereof tobe' cleaned,

repaired or the like withoutthe aid of. a special mechanic. Moreover, a smooth and uniform running without considerable wear of the con tacting parts is attained, as by the swinging out of the two abutments l3, l4 holding the bobbincase each of the abutments only moves a short one-of saidstops is adjustable.

distance, and consequently only requires to be moved at a slow speed.v

I claim:-- 7 1. A bobbin case controlling device for button hole and similar sewing machines, comprising in combination with a bobbin case, a two-armed escapement yoke pivotally mounted for rocking movement, a stop on eachof the arms of said yoke, a pair of stops on the outer side of said bobbin case for alternately cooperating with the respective stops on said yoke, one of said pair of stops disposed between the center of said bobbin case and the pivotal axis of said yoke, and the .other of said pair of stops disposed above the center of the bobbincase.

2. A device as specified in claim 1, in which PUDELKO.

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