JPS6326144Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a top cover mechanism of a sewing machine in which a spreader is reciprocated in front of a plurality of needles arranged in parallel to swing the top cover thread to intersect with a row of needle thread stitches.

Conventionally, this type of upper decoration mechanism has a swing shaft that swings in conjunction with the top shaft, a crank arm that is fixed to the swing shaft and swings in a vertical plane, and a crank arm that is perpendicular to the swing shaft and is connected to the spretzer. It consists of a vertical shaft that provides rocking motion, a crank that is fixed to the vertical shaft and can rotate in the horizontal direction, and a rod that connects the crank arm and the crank with a ball joint. The crank is oscillated through the machine to give the spretzer an oscillating motion, but because the structure is complex and the mass is large, vibrations caused by inertia become large during high-speed operation, making it difficult for high-speed sewing machines to operate. It was unsuitable for me.

The upper decoration mechanism as shown in U.S. Patent No. 2996023, that is, a pin protruding from the end of an arm that swings in a vertical plane in conjunction with the upper shaft can be rotated and slid on one side of the connected bushes. According to the above-mentioned upper decoration mechanism, which is slidably inserted into a cylindrical body that fits into the cylindrical body, and the other side of the bushing is fixed to an eccentric pin integrally formed with a vertically supported swinging shaft so that the mounting angle can be adjusted. This problem can be solved to some extent, but today's sewing machines have become even faster, with speeds of 6000S.PM.
In this case, even the above-mentioned mechanism is still insufficient, and resonance occurs in the mechanism, causing the spreader to swing in a larger amount than expected, which may impede seam formation.

The purpose of this invention is to further reduce the mass of the members constituting the top cover mechanism to obtain a top cover mechanism for a sewing machine that does not cause the above-mentioned problems even in high-speed sewing machines of 6000 S.PM or higher.

An embodiment of the present invention will be described below with reference to the drawings. A swing shaft 2 arranged in parallel with an upper shaft 1 is connected to the upper shaft via an eccentric cam, a rod 3, and a lever 4.
As a result, the swing shaft 2 swings in conjunction with the upper shaft 1,
The amount of rocking can be adjusted by adjusting the mounting position of a pin 6 passed through a long groove 5 formed in the radial direction of the lever 4.

A crank arm 7 is also attached to the shaft end of the swing shaft 2, and the lower end of the crank arm forms a cylindrical portion 18, which rotatably and slidably fits the pin 8, and extends in the diametrical direction of the pin 8. A crank pin 11 that projects from a crank 10 fixed to the upper end of the vertical shaft 9 is inserted into the round hole 19 provided in the opening 1 formed in the cylindrical portion 18 at the lower end of the crank arm.
A spreader 14 is attached to a metal fitting 13 that is inserted through the shaft 2 and held at the lower end of the vertical shaft.

The height of the spreader 14 can be adjusted by loosening the setscrew 15 and sliding it up and down, and by rotating it, the radius of rotation of the hook part 16 about the axis of the vertical shaft 9 can be adjusted. Loosen screw 17 and remove metal fitting 1
By changing the angle at which the rotor 3 is attached to the vertical shaft 9, its rotation range can be adjusted. When the swing shaft 2 swings in conjunction with the upper shaft 1 and the crank arm 7 swings, the pin 8 moves to the crank pin 11.
The crank 10 is oscillated together with the longitudinal shaft 9 by sliding on the top and axially inside the cylindrical portion 18 at the lower end of the crank arm, and the spretzer 14 is moved in the known manner to the needle 1.
Make a reciprocating motion on the front side of 5.

As described above, in the overlay mechanism of this invention, the lower end of the crank arm fixed to the swing shaft and the crank pin provided on the vertical shaft are connected by the pin of the sliding member fitted to the lower end of the crank arm. Since it is only necessary to have a size that allows the crank pin to be inserted, the mass can be made even smaller than the known one, and therefore even if used in a high-speed sewing machine, the vibration of the sewing machine due to inertial force will be reduced. It can be small and can also reduce the increase in the amount of swing of the spreader due to resonance.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a sewing machine equipped with a top cover mechanism according to the present invention, and FIG. 2 is an exploded perspective view of the top cover mechanism. 2... Swing axis, 7... Crank arm, 8... Pin, 9... Vertical axis, 10... Crank, 11... Crank pin, 14... Spretzder.

Claims (1)

[Scope of utility model registration request] An upper shaft 1 that is rotatably and horizontally supported within the sewing machine frame and has an eccentric cam fixed thereto; a rod 3 that fits into the eccentric cam and swings as the upper shaft 1 rotates; Rotatably supported pin 6
A lever 4 having a long groove 5 to which the position can be adjusted is fixed, and a swinging shaft 2 is supported on the sewing machine frame in parallel with the upper shaft 1, and the upper end is fixed to the swinging shaft 2. , a cylindrical part 1 parallel to the swing axis 2 at the lower end
8, and has an opening 12 formed in the lower surface of the cylindrical portion 18. The crank arm 7 is rotatably and slidably fitted in the cylindrical portion 18 in the axial direction, and has a round hole 19 in the diametrical direction. a vertical shaft 9 that supports a spreader 14 at its lower end and is rotatably supported on the sewing machine frame; and a crank 10 that integrally projects horizontally from the vertical shaft 9; erected in parallel,
A top cover mechanism for a sewing machine comprising a crank pin 11 that is inserted through the opening 12 and slidably fitted into the round hole 19.