JPS6117735Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a fabric presser device that feeds out the fabric to be sewn in a predetermined direction at a predetermined pitch by working in conjunction with a fabric feed dog that protrudes and retracts from the throat plate of a sewing machine bed.

In general, the presser foot device in this type of sewing machine consists of a presser foot attached to the lower end of a presser foot that is pressed down with a predetermined pressure by a presser spring, and a needle mounted on the sewing machine bed directly below the presser foot. It is composed of sawtooth-like cloth feed teeth that protrude and retract from the plate in the cloth feed direction and feed the cloth to be sewn in a predetermined direction at a predetermined pitch. Therefore, when the cloth feed dog protrudes from the plate surface of the throat plate, the presser foot bar is pushed up against the pressing spring by the protruding amount of the cloth feed dog via the cloth to be sewn and the presser foot. When the cloth feed dog retracts from the plate surface of the throat plate, the presser foot bar is pushed down together with the cloth feed dog by the presser spring, and the fabric to be sewn is pressed against the throat plate by the presser foot of the presser foot rod. It is designed to hold.

However, in the conventional presser foot device configured as described above, when the operating speed of the sewing machine increases, the number of times the cloth feed dog goes up and down increases, and the workpiece moves in conjunction with the cloth feed dog. The presser foot that clamps and feeds the cloth and the presser rod that is integrated with the presser foot are susceptible to high-speed lifting and lowering of the cloth feed dog due to their own inertia and the twisting phenomenon between the medallion that supports the presser foot. It is easy to cause a phenomenon in which the sewing machine cannot follow the sewing pattern faithfully and cannot accurately feed the cloth to be sewn at the set pitch. One way to deal with this phenomenon is to increase the elastic force of the presser spring that presses down the presser foot rod. However, if the presser spring is strengthened in this way, so-called "sewing wrinkles" may occur in the fabric being sewn. This has the disadvantage that "stitching misalignment" is more likely to occur.

Furthermore, as a means to eliminate such defects, a support arm having a pivoting arm extending in the cloth feeding direction is fixed to the hanging end of the presser foot rod, and a presser foot is attached to the end of the swinging arm. A cloth pressing device has been proposed in which the cloth presser foot is fixed and the cloth presser foot is pressed down toward the cloth feeding teeth of the needle plate.

That is, FIGS. 1 and 2 show this presser foot device. Reference numeral 1 denotes a sewing machine arm that is integrated with a bed 2. At a predetermined position on this arm 1, there is a sewing needle 21 that moves up and down every sewing cycle. Rod 3 is attached. Reference numeral 4 denotes a throat plate detachably attached to the upper surface of the bed 2 directly below the needle bar 3, and 5 is disposed below the throat plate 4, and a serrated cloth feed tooth 6 is fixed at a predetermined position. At the feed stand, this feed stand 5
The cloth feed dog 6 is moved to the throat plate 4 every sewing cycle.
The slit is made to protrude and retract from the slit at a predetermined pitch in a predetermined direction, and is provided to feed out the fabric to be sewn which is clamped by a cloth presser foot 15 which will be described later.
7 is a metal fixed to the arm 1 at a predetermined interval in parallel with the needle bar 3, and 8 is a hollow adjustment screw 17 screwed into the metal 7 and the upper part of the arm 1. This is a hollow presser rod that is supported so as to be able to rise and fall astride the presser pin 8, and a receiving pin 18 that is inserted into the upper part of the presser rod 8, and a lower part of the presser rod 8 that is swingably supported. A single cloth presser spring 20 is stretched between the press pin 19 and the elastic force of this cloth presser spring 20 is adjusted by rotating the adjustment screw 17 to raise and lower it. It is made so that it can be obtained. Reference numeral 9 denotes a stopper fixed approximately at the middle of the presser foot bar 8. An eccentric cam 10 rotated by a presser foot lifting lever 11 engages with the stopper 9. The cloth presser bar 8 is configured to be held at the upper limit position against the cloth presser spring 20, or to be released as shown in FIG. 12 is a support arm fixed to the hanging end of the presser foot bar 8 and having a free end extended by a predetermined amount in the direction opposite to the needle bar 3;
One end of a swing arm 13 is pivotally attached to the support arm 12 by a pivot 14 so as to be swingable. Therefore, the free end of the swinging arm 13 is arranged so that the hanging end of the press pin 19 in the work presser bar 8 is always pressed against it, and the elastic force of the work presser spring 20 is applied to the free end of the swing arm 13 together with the work presser bar 8. The pressure is reduced by a predetermined pressure. 15 is a cloth presser foot detachably attached to the free end of the swing arm 13 with a set screw 16;
It is well known that the presser foot 15 is provided with a slit through which the sewing needle 21 of the needle bar 3 can pass.

In the cloth presser foot device configured as described above, as shown in FIG. 13 is the cloth pressing spring 20
The fabric to be sewn (not shown) is swung on a trajectory of radius R with the pivot shaft 14 as a fulcrum against the elastic force of will be sent out. Therefore, cloth feed dog 6
The lightweight presser foot 15 operates as the
Since the presser foot 8 does not move up or down, its inertia is extremely small even when the sewing machine is running at high speed, and even if the cloth feed dog 6 moves up and down at high speed, the presser foot 15 does not move up or down. can be obtained by following
This means that the fabric to be sewn can always be fed accurately.

However, in the structure as described above, the presser foot 15 has the following structure as shown in FIG.
Since it swings in an arc shape on a locus with a radius R, the circular needle insertion hole is removed from the drop point of the sewing needle 21, so this should be carried out on sewing machines equipped with a presser foot that has a circular needle insertion hole. There is a drawback that it cannot be done.

This invention has been made in view of this point, and is intended to provide a presser foot device that can prevent the arcuate movement of the presser foot as required.

That is, in this invention, as in the embodiment shown in FIGS. 3 to 6, the base of the support arm 12 fixed to the lower end of the presser foot bar 8 is engaged with a protrusion 26, which will be described later. A locking member 23 having a notched groove 22 that prevents the swinging arm 13 integral with the swinging arm 13 from swinging is pivotally attached to the free end of the swinging arm 13 by a stepped screw 24. As shown in FIG. 5, a protrusion 25 is provided which engages with the aforementioned locking member 23 as necessary to prevent the swinging arm 13 from swinging. As shown in FIG. 3, 26 is a ring interposed between the locking member 23 and the head of the stepped screw 24 to hold the locking member 23 in an engaged state or an open state. A shaped elastic body 27 is a stopper for positioning the locking member 23 in the horizontal direction when the locking member 23 is in the open state, as shown in FIG. There is.

Since the cloth pressing device of this invention is constructed as described above, when the locking member 23 is held in the state shown in FIG. The presser foot 15 can smoothly follow the feed dog 6 to accurately feed the fabric to be sewn at a predetermined pitch, and the locking member 23 can be rotated about the stepped screw 24 as a fulcrum, as shown in FIG. As shown in FIG. 2, when this is engaged with the protrusion 25 of the swinging arm 13, the swinging arm 13 is prevented from swinging by the locking member 23, and the movement of the presser foot 15 is restricted only in the vertical direction. Therefore, even if the sewing machine is equipped with a presser foot having a circular needle insertion hole, the sewing function is not hindered and has an excellent effect.

Note that instead of providing the notch groove 22 in the above-mentioned embodiment, the locking member 23 may be provided with a small hole 28 that fits into the stopper 27 as shown in FIG. As shown in the figure, a protrusion 30 is provided at the free end of the locking member 29, and the swinging arm 13
It goes without saying that the same effect can be obtained by providing an engagement groove 31 in which the protrusion 30 engages.

[Brief explanation of the drawing]

Fig. 1 is a partially sectional front view of a conventional presser foot, Fig. 2 is an explanatory diagram of the operation of the presser foot, and Figs. 3 to 6 all show one embodiment of this invention. Fig. 3 is a side view of the main part, Fig. 4 is a sectional view taken along the - line in Fig. 3, and Fig. 5 is a side view of the main part showing the state in which a presser foot with a circular needle insertion hole is used. 6 are perspective views of essential parts. Also the 7th
8 and 8 are perspective views showing other embodiments of this invention. In the drawing, 8 is a presser bar, 12 is a support arm, 13 is a swing arm, 15 is a presser foot, 20 is a presser spring, 2
3 is a locking member. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] a swinging arm having a presser foot that is swingably pivoted to the free end of a support arm fixed to the downwardly hanging end of the presser foot rod and is constantly pressed down with a predetermined pressure by a presser spring; or a locking member rotatably attached to the support arm and having a locking portion at the other end; and an engaging portion that engages with the locking portion of the locking member provided on the support arm or the swinging arm. A cloth for a sewing machine, comprising: rotating the locking member as necessary to engage the locking portion with the engaging portion to prevent the swinging arm from swinging. Presser foot device.