JPH059262B2 - - Google Patents

Description

TECHNICAL FIELD The present invention relates to a device for welding synthetic materials having an upper pressure roller and a lower pressure roller and a drive for at least one pressure roller.

Prior Art According to West German Patent No. 874242, 2
It is known to weld a covering tape onto the joint seams of workpieces made up of two fabric layers. Such a welding joint, as known for example from DE 732 156, has a heating element and a pair of pressure rollers which are driven at a small distance behind this element. In the case of curved, especially spatially curved and at the same time wide weld seams, pressing folds of the workpiece are formed during the swiveling of the workpiece between the pressure rollers, which folds cause the tape to It is fixed by welding and the joint of the workpieces exhibits an unsightly appearance.

OBJECTIVES The object of the invention is to create a synthetic material welding device which allows even arcuate and spatially curved wide weld seams to be formed without forming pleats.

Structure, operation and effect The above-mentioned object is, according to the present invention, that the driven pressure roller has a central drive roller portion and at least two freely rotatable rollers arranged approximately symmetrically with respect to the central drive roller portion. This is achieved by having pressure rings which are arranged concentrically with respect to the central drive roller part and whose outer diameter corresponds to the outer diameter of the central drive roller part.

By dividing at least one of the pressure rollers into a central roller part connected to a roller drive and at least two pressure rings arranged symmetrically with respect to this and freely rotatable, these pressure rings are , as the workpiece swivels during feeding, it is automatically adjusted to a local velocity different from the linear velocity of the part of the workpiece that is clamped by these rollers and located near the instantaneous axis of rotation of the workpiece. It is possible to adapt. Thus, for example, when pivoting the workpiece clockwise in the case of a pressure roller with two pressure rings, the pressure ring on the right moves with less speed than the central roller part being driven and the pressure ring on the left with a greater speed. Rotate at speed. Due to the adaptation of the speed of the freely rotatable pressure rings, there is only a small relative velocity between these rings and the workpiece, which does not lead to creases in the workpiece. can avoid.

In the case of particularly wide weld seams and correspondingly wide pressure rollers, the pressure roller should be
It is expedient to divide it into three or more parts and, for example, to arrange two or more freely rotatable pressure rings on each side of a central driven roller part.

Claim 2 shows an advantageous design of the divided pressure roller.

Embodiments The present invention will be explained below with reference to embodiments shown in the drawings.

The casing of the welding device consists of a base plate 1 carrying a vertical column 2 and an arm 4 which transitions into a stand 3 and a head 5.

An upper pressure roller 7 is disposed on a carrier 6 fixed to the head 5 and is vertically displaceable under the force of a spring, and this pressure roller is driven by a drive mechanism (not shown). It is now drivable.

A lower pressure roller 9 is arranged on the shaft 8, which is supported on the column 2. The pressure roller 9 is connected to the shaft 8
It has a central roller part 10 fixedly arranged above, which is laterally formed with two central projections 11, 12. One ball bearing 1 is mounted on each of these projections 11, 12.
3 and 14 are fixed. These ball bearings 1
3 and 14 are each one pressure ring 15 or 1
It carries 6. The outer diameter of the pressure rings 15, 16 corresponds exactly to the outer diameter of the central roller section 10. The outer rings of the ball bearings 13, 14 and the pressure rings 15, 16 have a small axial clearance relative to the central roller part 10, so that the pressure rings 15, 16 are freely rotatable.

The shaft 8 is connected via a bevel gear transmission 17 to a shaft 18, which is connected to a drive mechanism (not shown). The upper and lower pressure rollers 7, 9 are driven synchronously, ie the upper pressure roller 7 and the central roller section 10 have equal circumferential speeds.

A carrier 19 of a storage roller 20 is fixed to the head 5, which storage roller is covered with a thermoplastic tape B.
is stored. There are two guides 2 on the front of the head 5.
1 is placed for tape B.

A hood-shaped carrier 22 is rotatably mounted in front of the head 5 and carries a hot air jet nozzle 23 . The hot air jet nozzle 23 can be moved by means of the carrier 22 into a rest position remote from the pressure rollers 7, 9 and into an active position close to the pressure rollers.

The operating mode is as follows.

For example, although not shown, an upper pressure roller may be used to weld tape B onto a bonding seam, for example formed as a thread seam, of an entirely thermoplastic workpiece or of a workpiece with a thermoplastic layer. 7 is lifted, the edge of the workpiece rests on the lower pressure roller 9 and the end of the tape is inserted between the workpiece and the upper pressure roller 7. The hot air jet nozzle 23 is then swiveled into the working position and the welding device is activated, so that the area of the workpiece located in front of the pressure rollers 7, 9 and the tape B is covered by the hot air jetted from the hot air jet nozzle 23. softened and subsequently pressed by pressing rollers 7, 9,
As a result, the softened areas of workpiece and tape are evenly bonded to each other. Central roller part 10
The workpiece is continuously fed by the feed movement transmitted to the workpiece by and to the tape by the upper pressure roller 7, and at the same time new tape is withdrawn from the storage roller 20, thereby removing the withdrawn tape. is welded onto the joint seam of the workpiece as a covering tape as it advances.

During the feed movement, the workpiece, which is supported on the lower pressure roller 9 and is in such a connected state that it frictionally entrains the two pressure rings 15, 16, carries the two pressure rings 15, 16 with them. The rotational speed of the rings is approximately equal to the respective speed of the part of the workpiece that is in contact with the rings. That is, the two pressure rings 15, 16 rotate with the same speed as the central roller section 10 when the workpiece is fed in a straight line, whereas these rings rotate with the same speed as the central roller section 10 when the workpiece is fed in a straight line, whereas these rings rotate when the workpiece is fed in a straight line. rotates at a rotational speed different from that of the central roller section 10 due to the pivoting movement of the workpiece carried out by the user of the sewing machine.
Thus, when the workpiece is pivoted clockwise, the right-hand pressure ring 16 rotates at a lower number of rotations than the central roller section 10, and the left-hand pressure ring 15 rotates at a higher number of rotations.

In this way, especially when the workpiece is composed of a non-thermoplastic fabric and a thermoplastic coated layer, the non-thermoplastic fabric maintains its normal stiffness during the welding process, while the workpiece is being pivoted. Even workpieces with a high risk of forming folds when pressed down are completely machined.

[Brief explanation of drawings]

FIG. 1 is a front view of a welding device having two pressure rollers, and FIG. 2 is an enlarged sectional view of the lower pressure roller. 9... Lower pressure roller, 10... Center roller portion, 11, 12... Center protrusion, 15, 16
...pressure ring.

Claims (1)

Claims: 1. A device for welding synthetic materials with an upper pressure roller and a lower pressure roller and a drive for at least one pressure roller, in which a driven pressure roller 9 is connected to a central drive roller section 10. , at least two freely rotatable pressure rings 15, 16 arranged approximately symmetrically with respect to the central drive roller part, the pressure rings being arranged concentrically with respect to the central drive roller part, and Welding device characterized in that their outer diameter corresponds to the outer diameter of the central drive roller section. 2. The pressure rings 15, 16 are located on the central protrusion 1 provided on the side of the central drive roller portion 10.
1, 12,
A welding device according to claim 1.