JPH0527162Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Industrial application field) The present invention relates to a thread tension device for a sewing machine.

(Prior Art) A thread tension device that applies tension to the sewing thread of a sewing machine uses a knob or the like equipped with a lead screw to attach a coil spring that abuts one side of the thread tension disc to the sewing thread held between a pair of thread tension discs. A structure is known in which the tension is adjusted by adjusting the clamping pressure by changing the operating length.

(Problem to be solved by the invention) In such a thread tension device, the pair of thread tension discs and the lower end of the knob are formed close to each other, making it difficult to carelessly hang the thread on the thread tension device. In this case, the thread will enter the gap between the thread tension disc and the mounting surface or between the thread tension disc and the knob instead of between the pair of thread tension discs, and it will not be possible to apply clamping pressure to the sewing thread correctly.

The thread tension caused by the thread tension device changes depending on the clamping pressure between a pair of thread tension discs and the contact area between the sewing thread and the thread tension disc. The position of the thread guide varies depending on the position of the thread guide, and if the thread guide is provided close to the thread tension disc to maintain a constant position of the thread on the thread tension disc, it is difficult to thread the thread through the thread guide, thread the thread through the thread guide, etc. It is difficult to perform the operation sufficiently, and in the case where the thread guide is provided away from the thread tension disc to facilitate the operation, there is a problem that the thread guide position varies.

(Means for Solving the Problems) In response to this problem, the present invention includes a spring means that applies clamping pressure by pressing a pair of thread tension discs that clamp the sewing thread of the thread tension device that applies clamping pressure to the sewing thread of the sewing machine. It is placed adjacent to the outer periphery of the adjustment knob to be adjusted,
A cylindrical tube part that covers the pair of thread tension discs is formed by a notch part for guiding the thread to a position opposite to a contact part of the pair of thread tension discs of an outer cylinder extending below the thread tension discs. It is composed of a thread guide groove and a guide pin that is placed so as to be exposed in the notch and guides and holds the sewing thread.

(Example) Next, an example of the present invention will be described in detail with reference to the drawings shown in FIGS. 1 to 3.

1 is a thread tension rod with a lead screw 1a on the tip side.
A slotted groove 1b parallel to the axis is provided at the tip. A flange portion 1c is integrally formed at the bottom of the thread tension rod, and a screw hole 1d formed in the flange portion allows the thread tension rod to be connected to the panel 1.
3 through the bottom 11a of the thread tension outer cylinder 11.
It is fixed by 2.

A pair of thread tension discs 2 and 3 are fitted onto the thread tension shaft 1 with their thread clamp holding surfaces facing each other, and a bridge is fitted onto the thread tension disc 3 to fit into the slotted groove 1b of the thread tension shaft 1. A thread tension spring outer cylinder 4 is fitted therein, and has a portion 4a and an inner diameter 4b that fits into the thread tension shaft 1. A plurality of protrusions 4c are provided on the lower surface of the thread tension spring outer cylinder.
is formed, and the projection 4c is connected to the thread tension disc 3.
is in contact with. Reference numeral 5 denotes a thread tension spring, which is formed with a rotation stopper portion 5a that fits into the slotted groove 1b of the thread tension shaft 1, and is fitted onto the thread tension shaft 1 through the smallest diameter portion 5b. Reference numeral 6 denotes a thread tension stopper, and a passing portion 6a that fits into the thread tension shaft 1.
and an inner diameter portion 6b that fits onto the outer diameter of the thread tension shaft 1, and the thread tension shaft 1 is provided with the slotted groove 1b.
It is formed so that it can move up and down while being guided by.

Reference numeral 7 denotes a knob lead screw, which has a screw 7a formed on its inner diameter portion to be screwed into the lead screw 1a, and has a knurl 7b formed on its outer periphery.

Reference numeral 8 denotes a thread tension indicating plate, and a convex portion 8a that fits into the slotted groove 1b of the thread tension shaft 1 is formed at the lower part of the plate. A display section 8c displaying an instruction mark 8b is formed at the upper part of the instruction plate higher than the flange section 8d. Reference numeral 9 denotes a thread tension knob, and inside thereof there is an inner diameter part 9a that fits into a knurl 7b formed on the outer periphery of the knob lead screw 7, and a small diameter part 9b that fits into the display part 8c of the thread tension indicator plate 8. The upper part has a thread tension scale of 10.
A recess 9c for fixing is formed.

On the inside of the thread tension knob, a convex portion 9d for engaging with the protruding portion 6c of the thread tension stopper 6 is formed on a part of the circumference as shown in FIG. 6, and is indicated by a solid line in the figure. The position is the position where the thread tension knob 9 is turned to the farthest left and the scale 0 is aligned with the indication mark 8b.The position indicated by the dotted line in the figure is the position when the thread tension knob 9 is turned to the farthest right. This is the position where scale 9 is aligned.

The assembled state of the above structure is as shown in FIG. 1, and the thread tension outer cylinder 11 has a rising portion 11b from the bottom portion 11a covering the lower outer circumference of the thread tension knob 9. An opening 11c is provided at the rising portion at a height where the pair of thread tension discs 2 and 3 face each other.

The opening extends to a range where guide pins 18 and 19, which are integrally fixed to the thread tension outer cylinder 11, are exposed in order to set the introduction position 16 and discharge position 17 of the sewing thread 15.

Next, the adjustment of the thread tension and threading of the sewing thread in the thread tension device of the present invention will be explained.

As shown in FIG. 1 in the assembled state, the thread tension shaft 1
The thread tension spring outer cylinder 4 is in contact with a pair of thread tension discs 2 and 3 that are fitted into the thread tension disc 1 and in contact with the flange portion. The tension of the pair of thread tension springs 5, which is disposed between the thread tension spring outer cylinder and the thread tension stopper 6 which abuts the lower end of the knob lead screw 7 screwed into the threaded portion of the thread tension shaft 1, A clamping pressure is generated between the thread tension discs 2 and 3. By rotating the thread tension knob in order to align the scale of the thread tension scale 10 fixed to the thread tension knob 9 fitted on the outer periphery of the knob lead screw 7 with the indication mark 8b of the thread tension indicator plate 8, the knob lead screw 7 is rotated. 7 is rotated and moved in the axial direction on the thread tension shaft 1 to change the spring length of the thread tension spring 5 and change the pressing force, thereby adjusting the tension between the pair of thread tension discs 2 and 3. Change the clamping pressure.

As for threading the thread tension device, as shown in FIG. By pulling it in the direction of the arrow along the arrow, the thread is guided between the pair of thread tension discs 2 and 3 and threaded as shown by the dotted line in the figure.

In this embodiment, the thread tension outer cylinder 11 is coaxial with the thread tension shaft and fixed to the panel at the same time, but the thread tension outer cylinder 11 is attached separately from the thread tension shaft 21 as shown in FIG. 211, or a thread tension outer cylinder part may be formed in a part of the panel 313 as shown in FIG.

(Effects of the invention) As described above, according to the invention, an opening is provided close to the outer periphery of the thread tension disc, and the thread is guided by the thread guide part covering the lower part of the thread tension knob, and the thread is guided between the thread tension discs. The thread can be easily threaded, and it is possible to prevent incorrect insertion between the thread tension knob and the thread tension disc, or between the thread tension disc and the mounting surface, as in conventional thread tension devices. Guide pins for positioning the sewing thread in the thread tension discs keep the thread in a constant position between the thread tension discs, making it possible to apply stable thread tension.

[Brief explanation of the drawing]

The drawings relate to an embodiment of the present invention, and FIG. 1 is a partial sectional view of the thread tension device, FIG. 2 is a top view of the thread tension device, FIG. 3 is an explanatory diagram of the components of the thread tension device, and FIG. The figure is a partial sectional view of another embodiment, FIG. 5 is a partial sectional view of another embodiment, and FIG. 6 is an explanatory diagram of one-turn stop of the thread tension knob. 11c is a thread tension spring which is a spring means, and a thread guide groove.

Claims (1)

[Scope of utility model registration request] A pair of thread tension discs that clamp the sewing thread, a spring means that presses the thread tension discs to apply clamping pressure, an adjustment knob that adjusts the spring means, and a portion below the adjustment knob and the pair of thread tension discs. A thread tension device for a sewing machine comprising a thread tension outer cylinder having a cylindrical tube portion covering an outer circumference of the sewing machine, the thread tension outer cylinder having a position opposite to the abutting portion of the pair of thread tension discs. A thread tension device for a sewing machine, which is provided with a thread guide groove formed by a notch for guiding the thread, and a guide pin for guiding and holding the sewing thread is arranged at a position exposed from the notch.