Sewing – Elements – Starting or stopping
Patent
1981-06-10
1984-01-24
Hunter, H. Hampton
Sewing
Elements
Starting or stopping
112220, 112275, 112255, 112260, 112324, D05B 6910, D05B 6922, D05B 4700
Patent
active
044269471
DESCRIPTION:
BRIEF SUMMARY
This invention relates to hand sewing machines, and provides improvements directed respectively to a work support platen, an upper thread feed, and a foot-operable control for an electric drive motor for the machine.
A support surface, for material being stitched, is located generally adjacent to the conventional presser foot, needle, and material feed mechanism. With hand sewing machines it is usual for the material to be passing over such area in the direction away from the operator, usually with general guidance by hand.
In certain conventional hand sewing machines the material is fed to the needle between a spring-loaded presser foot above the material, and a reciprocating serrated feed mechanism below the material and located below the presser foot.
To accommodate the present variety of synthetic and natural materials, the various thicknesses of cloth, a variable pressure can be applied between the presser foot and the feed mechanism. This can ensure an even stitch through all materials by virtue of the operator applying an optimum pressure on the presser foot. It is conventional to adjust the downward pressure of the presser foot by selection of any one of a number of settings of spring loading.
To place the material between the presser foot and the material feed mechanism prior to sewing, it is necessary to raise the presser foot to a certain height. A lever is located at the rear of the usual sewing head in a vertical line with the presser foot. When this lever is raised the presser foot will move farther away from the feed mechanism, and thus will permit material to pass freely between the two. This is normal procedure prior to or immediately after a sewing sequence and with the needle static and in the raised position.
It is desirable that a person operating a sewing machine shall be able to exercise the maximum degree of control over the sewing job in hand. Ideally, this is done with both hands in constant contact with the material and lightly pressed thereon and passing over the static work supporting surface, surrounding the feed mechanism, as sewing proceeds.
However, the sewing procedure often has to be interrupted due to additional hand operations being required, e.g. the lifting of the presser foot. This is usual, for instance, when changing the direction of a sewing run, forming a buttonhole, or attempting to sew through a heavy seam.
A first object of the present invention is accordingly to provide an improvement to overcome the need for the operator to resort to separate and additional hand operations during a sewing task, whereby the operator may have continual and constant contact with the material during sewing.
It is conventional in domestic sewing machines to provide means whereby the thread is released and subsequently "taken-up" from the lower rotary hook during the formation of each individual stitch. The expression "take-up" is intended, in the context of this specification, to refer to the act of a take-up arm in moving to draw back or take up the upper feed of thread during its circumvolution of a lower bobbin case and rotary hook.
Each stitch is formed by a single rotation of the lower rotary hook which draws off thread from a descending needle. Thread for the upper feed is taken to the needle from a reel and through a series of guides, a take-up arm and a tensioner.
In order that the thread shall be formed into a loop to make the stitch on the rotating lower hook, it is necessary for the rotary hook to draw off a suitable length of thread through the needle. This loop is made at the forming of each and every stitch.
However, there must be a facility to "take-up" and tighten each stitch by drawing the thread back through the rising needle at the completion phase of the stitch. This is carried out by the take-up arm through which the thread passes, as the arm moves in a phased sequence relative to the needle and rotating hook.
Certain features of the conventional take-up arm are undesirable inasmuch as the arm, by virtue of its function and operation, is of long length and in
REFERENCES:
patent: 2416941 (1947-03-01), Mueller
patent: 3044424 (1962-07-01), Kehrer
patent: 3331346 (1967-07-01), Firestein
patent: 3359931 (1967-12-01), Miller et al.
patent: 3599585 (1971-08-01), Myrick
Manufacturing Clothier, vol. 60, No. 12, issued Dec. 1979 (London, GB) see p. 44, columns 2 and 3
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