Method Of Making Sliding-clasp Fasteners

Abstract

This invention relates to sliding-clasp fasteners and in particular to the positioning of the end stops thereon, particularly at the opening end of the fastener. In accordance with the invention, a pair of linked or otherwise integralised end stops is formed at the location of the said opening end of the fastener and is bent around for securing to the stringers and, after being mounted in position, is separated into two individual stops. During the operation of forming and separating the stops, the fastener is in the closed condition.

Description

The present invention relates to sliding-clasp fasteners and particularly to a method of and apparatus for manufacturing and securing pairs of limit stops to limit the movement of the slider of such fasteners.

The movement of the slider of a sliding-clasp fastener must be limited both at the closed end as well as at the open end thereof. The limit stop at the closed end of the fastener is generally in the form of a common member joining both stringers, but at the open end, naturally each stringer requires its own stop.

It is known to punch or stamp two limit stops for the open end of such a fastener from two flat wires and to mount them simultaneously at the ends of both the stringers, the fastener itself having to be in the open condition when mounting the stop. The fastener can be opened in the mounting area of the stops by pulling up the slider from the open end of the fastener.

Furthermore, a method is known in which the limit stops at the open end of the fastener are mounted on fastener stringers or half-tracks not connected to one another, and subsequently the slider is pulled up from the subsequently closed end of the fastener.

It is common to all these methods that, when manufacturing complete sliding-clasp fasteners, one or more processes have to be carried out on half finished fasteners that are lined-up partly open and partly closed. Fasteners in this condition are, however, very difficult to arrange in exact positions for these processes, e.g. as regards setting and pressure tools, cutting blades, etc. A further disadvantage of the known method of manufacture consists in that the fastener tends to become unhooked and twisted, e.g. on the transport rollers used for assembly. It is also difficult to effect a lateral guiding or feeding of such fastener tracks. Therefore, considerable difficulties occur in the continuous automatic manufacture of sliding-clasp fasteners.

It is thus an object of the invention to simplify a continuous automatic manufacture of sliding-clasp fasteners by providing an appropriate method of manufacturing and securing the limit stops on sliding-clasp fasteners. It is a further object to provide apparatus or machine for carrying out this method.

According to the invention, a pair of linked limit stops is punched in a manner known for the hook-like interconnecting fastener elements, which is then bent, mounted on fastener stringers in the closed condition, and during or after mounting on the fastener, is divided into two individual limit stops.

Advantageously, the operation for dividing the pair of stops is initiated after the bending operation and terminated during mounting. Initiation of the division can be effected by forming a nick in the pair of stops by pressing a cutting edge into a recess of a bending matrix. The parts adjacent the nick can be bent, during the nicking operation over the bending edges defining the recess.

Advantageously, the dividing and securing operation may be carried out after mounting the pair of limit stops in a subsequent operation with the same tool. Thus, after rolling the hooks or claws of the pair of stops, a matrix is introduced as a counter-support for one cutting edge, into the free slot between the support tapes of the fastener in the central area of the pair of stops.

The dividing and securing of the stops may alternatively be carried out after the mounting operation by a second tool, as is effected for the interconnecting elements.

The invention relates also to a machine for carrying out the method, comprising a cutting, bending and a pressure stamper as well as a bending and rolling matrix, and wherein a cutting blade is mounted on the pressure stamper for separating the pair of stops.

The bending matrix preferably has, in the area in which the cutting blade of the pressure stamper extends with respect thereto, a recess having two bending edges and the roller matrix has a recess for receiving said cutting blade. Furthermore, when transferring the cutting blade to the pressure area of the pressure stamper, curves can be made.

The advantages achieved with the invention consist more particularly in that the limit stops at the open end of a sliding-clasp fastener can be mounted on the completely closed double stringers of the fastener, whereby the above-mentioned difficulties are minimised or removed. Since both the individual stringers of the fastener are in engagement when mounting the stops, it is ensured that the stops at both ends of the fastener will be at exactly the same level so that, on the one hand, the unsightly and disturbing appearance of the stop projecting beyond and to one side of the slider cannot occur when the fastener is closed and, on the other hand, a secure limitation of the slider travel is effected in that both the limit stops abut one another in the slider at the same level.

A further advantage of the invention consists in that for manufacturing both limit stops at the open end of the sliding-clasp fastener only one cutting and bending tool is required so that the machine can be essentially more simple and cheaper.

A particular advantage of the method according to the invention is to be seen furthermore in that for manufacturing the pair of stops, material of the same type and size can be used as for manufacturing the connecting part at the closed end of the fastener and these can be claw or hooked connecting parts of known design.

In order that the invention may be more clearly understood, reference will now be made to the accompanying drawings which show one particular embodiment thereof by way of example, and in which:

FIG. 1 shows a cross-section of a device for manufacturing and securing limit stops in the working position, in which the stops are not yet punched and bent,

FIG. 2 shows a plan view of the lower part of the device according to FIG. 1,

FIG. 3 shows a cross-section through the device according to FIG. 1 in a working position in which a pair of stops have been punched and bent,

FIG. 4 shows a cross-section through the device according to FIG. 1 in a working position in which a pair of stops is nicked,

FIG. 5 shows a cross-section through a device according to FIG. 1 in a working position in which a pair of stops has already been divided into two individual stops and the mounting operation has begun, and

FIG. 6 shows a cross-section through the device according to FIG. 1 in a working position in which both the stops have been mounted on the fastener .

Referring now to the drawings, FIGS. 1 to 6 show the procedure for manufacturing and securing two associated limit stops at the open end of the sliding-clasp fastener. FIG. 1 shows the device in its starting position. A flat wire 1 is laterally introduced in the direction of the arrow into the tool. A combined cutting and bending stamper 20 and a bending stamper 21 are jointly vertically displaceable below the flat wire 1 and a cutting and pressure stamper 7 is arranged separately so as also to be vertically displaceable. In a corresponding position to the cutting and bending stamper 20, a cutting plate 22 is fixed above the path of the flat wire 1. A laterally displaceable bending matrix 5 is located above the cutting and pressure stamper 7 and above the path of the flat wire 1.

A cutting blade 6 is located on the cutting and pressure stamper 7. The bending matrix 5 has in its lower area in which the cutting blade 6 of the pressure stamper abuts against it, a recess 8 having two bending edges 9. The cutting blade 6 of the cutting and pressure stamper 7 passes along two curves 14 into the pressure area 15.

A rolling matrix 13 is above the punching and bending device which has a recess 16 to receive the cutting blade 6 of the cutting and pressure stamper 7. Bulges 10 of the tape of the carrier tape 12 of a sliding-clasp fastener inserted into the tool come to rest in the depressions 23.

FIG. 2 shows the above-mentioned punching and bending device in plan view. The contours of a pair of limit stops 2 not yet bent having the claws or hooks 3 are clearly to be seen therein.

FIGS. 1 to 6 describe the sequence of operations for making and securing pairs of limit stops against movement of the slider, in detail. After the flat wire 1 has been inserted into the device, the cutting and bending stampers 20 and the bending stamper 21 are moved together upwardly in the direction of the arrow shown in FIG. 3. This action punches out a pair of limit stops 2 from the flat wire and its claws or hooks 3 are bent upwardly by 90.degree. by means of the inserted bending matrix 5. The position of the device after this punching and bending operation is shown in FIG. 3.

In the next operation, the cutting and pressure stamper 7 is pressed in the direction of the arrow in FIG. 4 upwardly against the bending matrix 5. Thus the nick 4 shown in FIG. 4 is made in the centre of the pair of stops 2. By reason of the recess 8 in the bending matrix 5, the pair of stops 2 is simultaneously bent during the nicking operation over the bending edges 9 of the recess 8. The nicking process is shown in FIG. 4 in its central stage.

Then the bending matrix 5 is withdrawn to the side against the direction of the arrow in FIG. 2 out of the path of movement of the cutting and bending stamper 20, the bending stamper 21, and the cutting and pressure stamper 7. Both the cutting and pressure stamper 7 as well as the cutting and bending stamper 20 and the bending stamper 21 can now be moved together upwardly towards the roller matrix 13. Subsequently the cutting and bending stamper 20 and the bending stamper 21 have become stationary by striking the roller matrix 13 and by pressing the carrier tape 12 of the fastener against the bending matrix 13, the carrier tapes are fixed in position, and the cutting and pressure stamper 7 moves further upwardly. The claws or hooks 3 of the stops 2 are pressed by their apices by means of the carrier tape and begin their rolling movement which is guided by means of the depressions 23 in the rolling matrix 13. By means of the counter pressure which arises when rolling, the nicked pair of stops is completely separated so that two individual limit stops 11 are produced. The position of the device after separating the pair of stops 2 into two individual stops 11 is shown in FIG. 5. By means of the approximate U-shaped form of the individual stops 11 before pressing, during rolling, the claw apices during the pressure operation, the bulges of tape 10 can be prevented from pressing outwardly in the direction of the central axis of the fastener from the stops 11.

By means of a further upward movement of the cutting and pressure stamper 7, the claws 3 are completely rolled about the tape bulges 10. The position of the device after the completed rolling operation and after the securing of the individual stops 11 is terminated, is shown in FIG. 6. The device can now be returned to its starting position as shown in FIG. 1, the flat wire 1 being advanced by one division of the claw part, and a new cycle can begin. The tape bulges shown are individual parts of metal sliding-clasp fasteners. Naturally the stops 11 can also be rolled about appropriately shaped seam and spiral parts in the case of plastics sliding-clasp fasteners.

It is particularly favourable for the manufacture of individual limit stops 11 to start with a clamp blank which is provided on both ends with at least one tapering apex or claw 3, on the one hand the point at one blank end being limited by the rectilinear extension of one blank edge and the same measured apex at the other blank edge by the rectilinear extension of the other blank edge, whilst the other parallel edges of all the apices form a steep angle with the extensions of the blank edges.

Should the method be executed with relatively simple bending and cutting tools then it is recommended in a further embodiment of the method, to undertake one part of the pre-forming operation such as, for example, the punching and bending outside the area of operation of the cutting and pressure stamper 7. Advantageously, the punching and bending tools operate at the same rate as the cutting and pressure stamper 7. The spacing between the punching and bending tool and the centre of the cutting and pressure stamper 7 must, therefore, amount to a multiple of the wire advance.

In a further embodiment, a matrix is used as a counter support for the cutting blade 6 of the cutting pressure stamper 7 and is inserted after rolling the claw 3 of the pair of stops 2 into the free slot between the carrier tape 12 in the central area of the pair of stops 2 and by pressure against this matrix separates the pair of stops 2 prepared as claw or hook-like interlocking elements and after withdrawing the matrix, by a further upward movement of the cutting and pressure stamper 7 presses on both the individual stops 11.

In a further modification, the process is divided into two; firstly, a claw-connecting part is applied to the stringer and this is subsequently separated by means of a further tool suitable for making the two individual limit stops 11.

Claims

I claim:

1. In a method for the manufacture of sliding-clasp fasteners which includes the step of making end limit stops at the opening end of the fastener, the improvement which consists in that a pair of associated limit stops is formed at the location of said opening end of the linked stringers, bent around said stringers and secured in position, whereafter said pair of stops is separated into individual end stop members.

2. A method according to claim 1, wherein said separating operation is initiated after said bending operation, and is terminated during mounting of said stops.

3. A method according to claim 2, wherein, for initiation of said separating operation, a nick is formed in said pair of stops by pressing a cutting blade into a recess in a bending matrix.

4. A method according to claim 3, wherein the parts of said stops adjacent said nick are bent during nicking, over two bending edges defining said recess.

5. A method according to claim 1, wherein said separating and securing operations are carried out by, firstly, mounting said pair of stops in the fashion of a claw-like connecting part by means of an appropriate tool, whereafter said separating operation is effected by the same tool.

6. A method according to claim 5, wherein, after rolling said claw-like parts, a matrix forming a counter-support for a cutting edge is inserted into the free space between the stringer tape of the fastener in the central area of the pair of end stops.

7. A method according to claim 1, wherein said separating and securing operations for said end stops is carried out after the mounting operation, by means of a second tool.

8. Apparatus for manufacturing and securing limit end stops in a method according to claim 1, said apparatus having a cutting, bending and a pressure stamper in addition to a bending and a rolling matrix, wherein said pressure stamper has a cutting edge for separating said pair of end stops into two.

9. Apparatus according to claim 8, wherein said bending matrix is recessed in the area in which said cutting blade extends, said recess having two bending edges.

10. Apparatus according to claim 8, wherein said roller matrix is recessed to receive said cutting blade.