US2981214A

US2981214A - Stitching apparatus and particularly sewing machines

Info

Publication number: US2981214A
Application number: US557209A
Authority: US
Inventors: Judet Henri
Original assignee: Sagem SA
Current assignee: Sagem SA
Priority date: 1955-01-10
Filing date: 1956-01-03
Publication date: 1961-04-25
Anticipated expiration: 1978-04-25
Also published as: GB824830A

Description

April 25, 1961 H. JUDET 2,981,214

STITCHING APPARATUS AND PARTICULARLY SEWING MACHINES Filed Jan. 5, 1956 v INVENTOR 50.2 HENRI JUDET y WM, Wa/Z (ft/r.

United States Patent STITCHING APPARATUS AND PARTICULARLY SEWING MACHINES Henri Judet, Paris, France, assignor to Socit dApplicatrons Generales dElectricit et de Mcanique SAGEM, Paris, France Filed Jan. 3, 1956, Ser. No. 557,209 Claims priority, application France Jan. 10, 1955 4 Claims. (Cl. 112-58) This-invention relates to stitching apparatus, and particularly though not exclusively to sewing machines of the type adapted to provide lock stitches as used in stitching soles to footwear and similar purposes.

In machines of the type contemplated the mechanism is so designed that as a stitching operation is arrested the thread is stopped substantially at the midpoint of its upward stroke and the length of the thread involved in the stitching process is engaged by the hook of the needle. Because of this, the disengagement of the thread for removing the work from the machine requires a comparatively lengthy operation, especially in cases where the machine is provided with a bifurcated pressenfoot and in the case of a moccasin stitching machine.

Moreover, on starting a stitching operation, the thread tightening-means is so positioned that the operator has to hold the thread with his hand in order to ensure a proper formation of the initial loop.

Objects of the invention include the provision of improvements in machines of the above specified type, whereby the idle periods consequent on the necessity to disengage the thread on interruption of stitching, and to hold the thread on starting or resuming the work are eliminated.

In accordance with one aspect or feature of the invention, means are provided which eliminate the requirement for holding the thread manually on starting the machine. The means provides a reserve store of thread as the machine is stopped, so that the stored length of thread will be released the next time the machine is started. Thus the machine will then perform its initial stitching cycle without the operator having to draw a length of thread through the work carrier table.

The above storage means comprises a lever operated by the machine brake and operative to constrain the thread to form an additional loop along its path of feed, whereby there will be stored during the stoppage period a predetermined length of thread that will subsequently be released as the machine is again started in operation.

Further aspects, features and advantages of the invention will appear from the ensuing description which re lates to an exemplary embodiment of the invention given by way of indication but not of limitation. Reference will be made to the accompanying drawings wherein:

Fig. 1 is a front view of the dual thread-blocking arrangement with the novel storage mechanism, shown in the position assumed during the inoperative condition of the machine.

Fig. 2 is similar to Fig. 1 except that the parts are shown in the positions assumed on depression of the clutch pedal just before the initial stitching cycle.

The machine comprises a conventional hook needle, a loop forming device and a thread tightening device all as well-known to those familiar with this art.

The thread storing device will now be described with reference to Figs. 1 and 2.

A bell-crank lever 28 has a roller 29 journalled to a longer one of its arms and is pivoted at 30 on a support 2,981,214 Patented Apr. 25, 1961 ice 31 forming part of the machine frame. The other arm of lever 28 has a link 32 pivoted to it at 33 and the other end of the link being pivoted at 34 to a lever 35 journalled at 36 in the support 31. Also pivoted at point 34 is the swivel end of a link 37. The opposite swivel end of link 37 is pivoted at 38 to an arm 39 secured to the afore-mentioned shaft 25 operated from the machine brake.

As the operator releases the clutch pedal of the machine, the automatic blocking or brake device is actuated. The shaft 25 is rocked by a predetermined angle.

During operation of the automatic brake on release of the foot pedal by the operator, the rotation of shaft 25 simultaneously causes an angular motion of lever 39 (Figs. 1 and 2). This lever moves from the position shown in Fig. 2 assumed by it during the operative period of the machine to the position shown in Fig; '1. Lever 39 actuates the rod 37 which in turn acts on lever 28 through lever 35 and link 32 to constrain lever 28 to describe a rotational movement whereby lever 28 is moved from the position shown therefor in Fig. 2 to the position indicated in Fig. 1. At the end of this movement of lever 39 the

pivotal centers

33, 34 and 36 are all substantially aligned so that a slight variation in the amount of displacement of lever 39 will have no influence upon the end position of lever 28. The thread guide roller 29 has meanwhile been operated by lever 28 to draw a loop of thread in between blocking roller 40 and return roller 41, the thread being taken from the storage source since the upper latch device 42 is blocked while the roller '40 is released.

On depression of the clutch pedal the lever 39 drops back to the position illustrated in Fig. 2, restoring lever 28 to the position indicated in that figure.

The initial stitching cycle will use up the necessary amount of thread for forming the loop stitch previously drawn out and placed in store as shown in Fig. 2. Thus it is seen that the thread does not have to be drawn out of the work nor will it have to be held by the operator as was previously required in making the initial stitch.

It will be understood that the invention is not limited to the form of embodiment illustrated and described, and that many modifications may be made therein. Thus the improvements of the invention are applicable to sewing machines of the types adapted to produce both lock stitches and chain stitches, whether or not the machine is equipped with automatic braking means.

What I claim is:

1. In a sewing machine having a clutch and a brake operating control connected to a shaft and means operable on actuation of said control for operating the stitching elements of the machine, a thread measuring mechanism comprising means connected to said control for storing a length of thread on release of said clutch and operation of said brake at the end of a stitching operation and means for releasing said length of thread on operation of said clutch and release of said brake at the start of a stitching operation.

2. In a sewing machine having a clutch and a brake operating control connected to a shaft and means operable on actuation of said control for operating the stitching elements of the machine, a thread measuring mechanism comprising means connected with said control for storing a length of thread on release of said control at the end of a stitching operation and for releasing said length of thread on actuation of said control at the start of a stitching operation.

3. In a sewing machine having a clutch and a brake operating control connected to a shaft and means operable on actuation of said control for operating the stitching elements of the machine, a thread measuring mechanism comprising means defining a path for thread through said-machine, a lever to engage said thread and tion on actuation of said control at the start of a stitching operation.

4. In a sewing machine having a clutch and a brake operating control connected to a shaft and means operable on actuation of said control for operating the stitching elements of the machine, a thread measuring mechanism comprising a shaft operated by said control, a bell crank lever having a thread engaging roller on one arm, means interconnecting said shaft and said bell crank lever to oscillate the latter from a first position to a second position where the length of thread measured is greater on release of said control at the end of a stitching operation and means for restoring said lever to said first position'o'n actuation o a stitching operation.

References Cited in the file of this patent UNITED STATES PATENTS Roberts Aug. 12, Johnson Dec. 30, Valois July 24, Zaleski Dec. 1, Lindgren July 13, Reed Oct. 16, Benjamin Sept. 24, Gouldbourn Dec. 25, Gouldbourn et al. July 28, Haas May 21, Whitaker June 25, Larson June 17, Haas May 9, Hazelton Oct. 23, Artzt et a1. May 10,

f said control at the start of