JPS5857197B2 - Sewing machine koubutsu clamp unit tie sle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a low friction device for clamping sewing machine workpieces.

Workpiece clamps are commonly used in industrial machines, such as barbed stitch sewing machines, which start periodically and perform all operations automatically and then stop.

Such cyclical sewing machines are designed to perform specific functions repeatedly, such as attaching belt loops, sewing buttons, buttonholing, or attaching pockets.

Workpiece clamps are commonly used to ensure that seams are formed accurately without requiring much attention from the operator, thereby substantially reducing the possibility of error.

The workpiece clamping device is adapted to hold the workpiece between a lower workpiece clamp located proximate the sewing machine throat plate and an upper spring-loaded workpiece clamp.

The upper and lower clamps are supported by arcuate clamping frames, which are actuated by cams to effect the desired cyclic movement.

Current cycle-operating sewing machines are limited in their operating speed in part due to friction between the lower workpiece clamp and the throat plate.

As speed increases, the bolt stitches produced by the sewing machine become uneven and less repeatable due to friction and changes in friction.

This friction still creates significant stress on some of the parts, which also causes uneven work.

Therefore, in the case of a bolt-stitch sewing machine, in order to ensure uniformity of the product, it is necessary to limit the seam forming speed to a maximum of 2000 stitches per minute.

Attempts have been made to solve this problem by applying Teflon coatings to critical parts or by applying highly abrasive finishes to these parts, but these have not been able to increase machine speeds and increase production. .

Note that it is not desirable to lubricate the parts, since these parts are located near the material to be processed, and there is a risk of contaminating the material.

Previous attempts have been made to use permanent bearings to solve the friction problem, but this not only contaminates the material in close proximity to the lubricated parts, but also reduces the amount of fabric under the needle. Increase the fluttering of.

It would therefore be desirable to have an apparatus that would reduce workpiece clamp friction and substantially increase speed without reducing clamping capacity or creating workpiece contamination problems.

This object is achieved according to the invention in that, when the sewing machine needle is raised, a plastic-lined socket carrying a ball bearing passes through the needle plate and is lifted under the workpiece clamp.

The workpiece clamp is supported within the sewing machine by an arcuate clamping frame that moves the workpiece clamp according to a cam located in an intermediate base of the sewing machine.

The arcuate clamping frame supports a leaf spring which presses the upper workpiece clamp against the lower workpiece clamp and clamps the fabric between these clamps, while exposing the lower workpiece clamp. □Press it against the thin needle plate.

The reaction of the pressure of the workpiece clamp against the throat plate or the ball bearing in the plastic-lined socket lifted through the throat plate causes the pressure reaction of the workpiece clamp to occur in the plastic-lined socket supported on the top of the arcuate clamping frame. Underwritten by similar ball bearings.

The upper ball bearing abuts a hardened steel plate carried on the underside of the sewing machine arm.

Next, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows a sewing machine 10 having an overhanging arm 11 which projects from a mechanism 13 and has a head 12 at its end.

Said mechanism 13 is connected to an intermediate foundation 15 as well as a workpiece support bed 16 with a workpiece support throat plate 17 .

A main shaft 20 extends through the overhanging arm 11, and a drive pulley 21 is mounted on this main shaft.

The conventional mechanisms for driving the needle bar and the needles 24 attached thereto are not shown.

The driving pulley 21 is connected to a fishing shaft driving pulley 26 by a belt 25, and this pulley 26 is attached to a hook driving shaft 27 located within the bed 16 of the sewing machine.

A hook 28 attached to the end of the hook moving shaft 27 facing the hook moving shaft pulley 26 cooperates with the needle 24 when lock stitching is performed.

To achieve this purpose, the drive pulley 21 and the hook drive shaft pulley 26 have a 2:1 ratio, and the hook drive shaft 27
A hook 28 attached thereto rotates at twice the speed of the main shaft 20 and the needle 24 operatively connected thereto.

A workpiece clamping device is positioned below the overhanging arm 11.

Details of this workpiece fastening system are described in particular in U.S. Pat.

The description of this workpiece fastening device is limited to the extent necessary for understanding the present invention.

As shown in FIG. 1, the workpiece clamping assembly includes an arcuate clamping frame 3
0, the frame is attached by screws 31 to a base part 32 on the bed 16.

The base part 32 and the arcuate clamping frame 30 are moved by cam followers 35, 36 in synchronism with the needle 24 being withdrawn from the work fabric.

The cam followers are actuated by cam tracks 37, 3B in a cam 40 located in the intermediate base 15 of the sewing machine 10.

The cam 40 is carried by a gear 41 which is driven by a drive gear 42, said drive gear 42 being connected to the main shaft 20 of the sewing machine.
operably connected to.

Suspended from the arcuate clamping frame 30 is an upper workpiece clamp 46 by a shank portion 45.

A leaf spring 48 passes through the arcuate clamping frame 30 and impinges on an extension of the shank portion 45 and clamps the upper workpiece clamp 4.
6 is fired towards bed 16.

Adjustment screw 49 contacts leaf spring 48 and is adapted to increase or decrease the force exerted on shank portion 45 of upper workpiece clamp 46.

A projecting stud 50 engages said shank portion 45 and engages said shank portion 45 and the upper workpiece clamp when an angle reader 51 mounted on a presser foot lifting mechanism is lifted by said mechanism into a position abutting said projecting stud. 46 is lifted against the force of a leaf spring 48.

A lower workpiece clamp 56 is attached to the free end of the base part 32 by means of a screw 55.

In the needle penetration position, this lower workpiece clamp 56 is supported by the needle plate 17.

The workpiece fabric is sandwiched between the upper workpiece clamp 46 and the lower workpiece clamp 56, and the two clamps and the workpiece fabric are pressed against the needle plate 17 under the action of the leaf spring 48, so that the workpiece fabric is It is designed to prevent flapping.

Lifting shaft 60 is positioned within workpiece support bed 16 and supported by bearings therein.

The driving gear 61 attached to the hook moving shaft 27 is the lifting shaft 60
It meshes with a lifting shaft gear 63 attached to one end of the shaft.

The gears have a ratio of 2:1 and therefore the lifting shaft 60 rotates at the same speed as the main shaft 20 since the drive pulley 21 and the fishing shaft pulley 26 have a ratio of 2:1.

A hole eccentric to the center line of the shaft is formed at the end of the lifting shaft 60 facing the lifting shaft gear 63, and a headed pivot pin 65 is inserted into this hole and held by a set screw 64. and thereby form the crank.

Lifting shaft connecting link 66 by said pivot pin 65
(Fig. 2) is rotatably supported.

The lifting shaft connecting link 66 is formed with a pair of slots 68 at an end opposite to the end mating with the pivot pin 65 for receiving a lever 70, which is inserted around a pin 71 fixed to the shaft link. It is designed to vibrate at.

The lever 70 is pivoted in its center on an adjustment pin 74 which is held in the adjusted position in the bed 16 by a set screw 75.

The adjustment pin 74 is used to make adjustments as described below, has an eccentric shaft extension, and is held relative to the bed 16 by a set screw 75.

Thus, when pin 74 is screwed into bed 16 through screwdriver slot 76, the slope of lever 70 about pin 71 changes.

When the adjustment position is reached, the set screw 75 contacts the adjustment pin and maintains this specific set state.

Lever 7 opposite end capable of oscillating around pin 71
At the 0 end, the lever is pivotally mounted on a push rod wing, said push rod extending upwardly on either side of the rotating fishing shaft 27 (FIG. 2).

A bearing device 85 (FIG. 3) is pivotally supported at the end of the push rod 83, the bearing device having a tipped end 86 and made of a molded or molded anti-friction synthetic resin polymer 87. A socket 88 is formed in the polymer to receive the ball portion.

The synthetic resin polymer is preferably polytetrafluoroethylene or something substantially equivalent thereto.

The ball has a sufficient diameter for the load to be supported.
It is necessary to avoid creating dents in the synthetic resin polymer.

As shown in FIG. 2, the ball 90 projects through the throat plate 17 to some extent and can be adjusted by operating an adjustment pin 74.

As seen in FIG. 1, the ball projects through the throat plate 17 and under the lower workpiece clamp 56 and, against the action of the plate spring 48, pushes the lower workpiece clamp shell and the upper workpiece clamp 46. Lift up.

A race plate 95 made of hardened steel is attached to the lower side of the extending arm 11 above the arcuate fastening frame 30.

Said arcuate clamping frame 30 supports a second bearing device 97, which is a molded or molded insert 98 of a synthetic resin polymer, preferably polytetrafluoroethylene.
are accepted.

A socket 99 for receiving the ball 100 is formed in this insert member.

Ball 100 and race plate 9 are adjusted by adjusting screw 101.
50 is absorbed and the position thus obtained is maintained by the nut 102.

Therefore, conventionally, sliding friction occurs in the member subjected to the fastening pressure, but in the case of this device, it becomes rotational friction.

In the present invention, a synthetic resin polymer is used, and this material has very low friction, and its coefficient of static friction is similar to the coefficient of kinetic friction.

By making these changes, it was possible to increase the maximum speed of the sewing machine from 2,000 revolutions per minute to 4,000 revolutions per minute.

Although the figure shows only two balls for lifting the lower workpiece clamp 56, this principle allows for a larger number of balls to be used to lift the workpiece to achieve a low-friction movement. It can also be used when lifting the entire support surface.

Experiments have shown that the reason for lowering the workpiece clamp when the needle passes through the workpiece is to prevent the workpiece from flapping.

This flapping is caused by the sewing needle passing through an imperfectly supported fabric and deflecting the material.

If the ball 90 of the present invention were to remain in the raised position all the time, flapping would occur which would adversely affect the formation of the thread loop and cause skipped stitches.

For these reasons, the need for the mechanism according to the present invention is clear.

[Brief explanation of drawings]

FIG. 1 is a partially sectional front view of a □ thin in which the present invention can be implemented. FIG. 2 is a cross-sectional view taken substantially along line 2--2 of FIG. FIG. 3 is a sectional view of the ball bearing and the synthetic resin socket, showing details of its structure. FIG. 4 is a cross-sectional view taken substantially along line 4--4 of FIG. In the figure, 10 is a sewing machine, 11 is an extended arm, 12 is a head,
13 is a mechanism, 15 is an intermediate foundation, 16 is a bed, 17 is a throat plate, 20 is a main shaft, 21 is a drive pulley, 23 is a needle bar, 2
4 is a needle, 25 is a belt, 26 is a fishing shaft drive pulley, 27
is a hook moving shaft, 28 is a hook, 30 is an arcuate fastening frame, 31 is a screw, 32 is a base part, 35, 36 is a cam driven member, 40 is a cam, 41 is a gear, 42 is a drive gear, 45 is a shank 46 is an upper workpiece clamp, 48 is a leaf spring, 49 is an adjustment screw, 50 is a protruding stud, 51 is an angle readout,
55 is a screw, 56 is a lower workpiece clamp, 60 is a lifting shaft, 61 is a drive gear, 63 is a lifting shaft gear, 64 is a set screw, 65 is a pivot pin, 66 is a connecting link, 68 is a slot, 70 is a lever , 71 is a pin, 74 is an adjustment pin, 75
76 is a set screw, 76 is a slot, 83 is a push rod, 85 is a bearing device, 86 is a tip-shaped end, 8T is a resin polymer, 88 is a socket, 90 is a ball, 95 is a race plate, 97 is a second bearing 98 is an insertion member, 99 is a socket, 100 is a ball, 101 is an adjustment screw, and 102 is a nut.

Claims (1)

[Claims] 1 comprising a frame, a sewing machine needle, and a device for reciprocating the sewing machine needle up and down through the material to be processed, the frame having a bed provided with a hole for causing the reciprocating movement of the sewing machine needle; Furthermore, a workpiece clamping device for supporting and transporting the workpiece on the bed and having an upper clamp member and a lower clamp member; a device for supporting and transporting said workpiece fastening device upon exit; at least one ball and bearing device operating between said bed and said workpiece fastening device; a device comprising a socket for receiving a ball and moving said bearing device to place said ball in a space between said bed and a lower clamping member of said workpiece clamping device in synchronism with the upward movement of said needle; and a device adapted to lift the workpiece fastening device by means of the balls that impinge on the lower clamp member prior to conveyance of the workpiece fastening device.