The invention relates to a method for producing closure elements for metal touch-and-close fasteners, whereby notches, corresponding to the outline of the hooking elements to be formed, are made in a metal carrier while leaving a respective connecting line, and bending processes are carried out in order to raise the regions bordered by the notches as hooking elements around the connecting lines serving as bending lines, out of the plane of the carrier. Moreover, the invention relates to a closure element produced according to this method.
A method of the aforementioned type is already disclosed in DE 10 2006 015 145 A1. Producing a type of metal touch-and-close fastener makes it possible to use the advantages of proven plastic-based touch-and-close fastener systems, as have become widely used for a plurality of applications, and also in those applications in which plastic touch-and-close fasteners cannot be used, for example due to the lack of temperature stability, overly low mechanical strength, and the like. In hooking elements consisting of temperature-resistant metal alloys, for example high-grade steel, these metal touch-and-close fasteners can also be used in areas of application in which high thermal and mechanical loads occur. These fastening systems enable prompt and simple mounting of third parts without the need for additional holding devices and their actuation by special tools.
One major disadvantage of metal touch-and-close fastener systems, however, consists in that production of closure elements is complicated compared to plastic-based touch-and-close fasteners, time-consuming, and therefore expensive. Difficulties in this respect are due to the fact that for producing a sufficient number of hooking elements a large number of notches must be made, for example by punching, after which processes of shaping by bending must be carried out on each region of the pertinent carrier bordered by the notches in order to raise the hooking elements and to bring them into the hook shape which is suitable for hook engagement.
In this context, the object of the invention is to make available a method by means of which simple, efficient, and thus economical production of closure elements for metal touch-and-close fasteners is enabled.
This object is achieved according to the invention by a method having the features of claim 1 in its entirety.
According to the characterizing part of claim 1, the essential feature of the invention consists not only in that complete execution of each hooking element is carried out by a combined working step that comprises both the cutting process and also the embossing process that effects shaping by bending, but that the respective combined cutting and embossing process is carried out in a continuous process by the carrier being routed through the engagement region of the intermeshing teeth of bodies of revolution. In this way, an extremely large number of hooking elements, proceeding from a still unprocessed carrier, can be formed in continuous process at a very high operating speed to the final finished state. Thus metal touch-and-close fasteners can be produced especially efficiently and with a very high operating speed.
Preferably, the arrangement is made such that at least one of the bodies of revolution is set into rotation by a drive and the carrier in the form of a strip is pulled through the engagement region of the teeth by the feed force produced by the drive. Especially high operating speeds can thus be achieved.
Especially advantageously, several adjacent rows of hooking elements can be formed on the pertinent carrier by means of bodies of revolution in the form of roller disks which have several adjacent rows of teeth on their periphery.
In the process, notches in a rectangular shape are preferably formed whose long sides run in the direction of the teeth and whose at least one short side is formed by the connecting line which has been left.
One especially advantageous pattern of the hooking elements can be formed in such a manner that for adjacent rows of hooking elements they are designed such that the hooking elements in rows adjacent to one another are offset to one another in the longitudinal direction such that the hooking elements are aligned to one another in every other row.
It is possible to proceed such that the hooking elements in each row are raised by the bending taking place in the same direction around the bending line or that the hooking elements in rows adjacent to one another are raised with bending directions which are opposite one another around the bending line. Depending on the requirements that prevail in the respective application, touch-and-close fasteners can be implemented which make available the desired holding force against lifting of the carriers off one another and a defined locking force against displacement movements of the carriers.
In this context, it can be advantageous if the hooking elements in each row are raised with alternating bending directions around the bending line.
The subject matter of the invention is also a closure element produced according to the method according to the invention having the features of claim 9.
The invention is detailed below using exemplary embodiments shown in the drawings.
FIG. 1 shows a perspective oblique view of one section of one exemplary embodiment of the closure element according to the invention;
FIG. 2 shows a side view of the section shown in FIG. 1;
FIG. 3 shows a top view of the section shown in FIGS. 1 and 2;
FIG. 4 shows a highly schematically simplified perspective oblique view in which only that part of a device is shown in which combined cutting and embossing processes take place by means of tooth engagement to illustrate the progression of the method according to the invention;
FIG. 5 shows an oblique view of a second exemplary embodiment of the closure element similar to FIG. 1;
FIG. 6 shows a side view of the section shown in FIG. 5;
FIG. 7 shows a top view of the section from FIG. 5; and
FIG. 8 shows a partial representation similar to FIG. 4 to illustrate the progression of the method for producing closure elements with hooking elements in a C-shaped hook form.
FIG. 4 illustrates the progression of the method according to the invention for producing closure elements with hooking elements 1 which have a hook shape, as is shown in the examples from FIGS. 1 to 3, where not all hooking elements 1 are numbered. As can be taken from FIG. 4, a still unformed, strip-shaped metal carrier 3, for example of a high-grade steel alloy and with a material thickness which can be 0.1 to several mm, depending on the application of the closure element which is to be produced, is routed through the region 5 of tooth engagement between two revolving roller disks 7 and 9 having peripheral teeth, with guide rolls 11 being located in front of and behind the engagement region 5. In the example from FIG. 4, at least one of the roller disks 7, 9 can be rotated by means of a drive so that the carrier strip 3 is pulled through the region 5 by the feed force acting in the engagement region 5, i.e., is moved to the left in FIG. 4. As is likewise apparent from this figure, the tooth shapes and flank clearance are selected and matched to one another such that in the region 5 on the carrier strip 3, which has not yet been worked, a combined cutting and bending process takes place in which the teeth of the roller disk 9 carry out a type of punching process from the side of the strip 3 which is underneath in FIG. 4, whereby notches 13, of which only some are numbered in the figures, are formed in the shape of rectangles that are elongated in the feed direction, the rectangular shape being closed on the connecting lines 15; said connecting lines extend in the transverse direction to the feed direction and form bending lines around which the respective inner region of the notches 13 is raised. This takes place by the front region of the teeth of the roller disk 9, which are active not only in cutting (punching), but the pertinent regions also pressing into the tooth gaps 17 (only a few in FIG. 4 are numbered) of the roller disk 7, the inside walls of the tooth gaps 17 being shaped such that pressing the material regions into the tooth gaps 17 conducts an embossing process for forming the tooth shape of the hooking elements 1 which is shown in FIGS. 1 to 4.
As is best illustrated in FIGS. 1 and 2, the hooking elements 1 adjacent to the bending lines, i.e., the connecting lines 15, each have a base part 19 which runs obliquely to the plane of the carrier strip 3 as well as a hook end part 21 which is connected to the foot part and which is arched in the direction to the carrier strip 3. These hook end parts 21 are only numbered in FIG. 2 and partially in FIG. 3.
While in FIG. 4 a narrow carrier strip 3 is pulled through the region 5 in which there is only one row of teeth for forming only one row of hooking elements 1, FIGS. 1 to 3 illustrate examples in which six adjacent rows of hooking elements 1 are formed at the same time by means of several adjacent rows of teeth. As is best illustrated in FIGS. 1 and 3, the hooking elements 1 for all adjacent rows are shaped the same, the bending direction in which the hooking elements 1 are bent around the connecting lines 15 being the same within each row. But, for the rows adjacent to the hooking elements 1 which are aligned with one another in the transverse direction, the bending direction is reversed so that the hooking elements 1 which are aligned with one another in the transverse direction are oriented the same in every other row.
In contrast, the example shown in FIGS. 5 to 8 differs essentially in two respects. On the one hand, each of the rectangular notches 13 is bordered on the two short sides by a connecting line 15, of which only some are numbered in the figures, and the hooking elements 1 have a C shape. As FIG. 8 illustrates, this is effected by the teeth of the roller disk 9 having a centrally placed, projecting cutting edge 23 which runs in the transverse direction and which, when the teeth engage, engages a die depression 25 in the tooth gaps 17 of the roller disk 7 such that the carrier strip 3 is cut by the cutting edge 13. In this way, one partial inner region of each notch 13 at a time can be raised around one connecting line 15 and another, i.e., two hooking elements 1 result on each notch 13. These hooking elements, according to the shape of the tooth gaps 17 of the roller disk 8, are embossed in a C-shape, i.e., they have a continuous arch proceeding from the base part 19 to the hook end part 21. For the sake of clarity of the drawings in FIGS. 5 to 8, not all the notches 13, connecting lines 15, tooth gaps 17, base parts 19, and hook end parts 21 are numbered.
FIGS. 5 and 7 illustrate the arrangement and orientation of the C-shaped hooking elements 1. As is apparent, the hooking elements 1 in the rows are each bent alternately in one or the other bending direction around the connecting lines 15 so that for successive hooking elements 1, the open sides of the C-shape are facing one another. The hooking elements 1 in the adjacent rows, as in the example from FIGS. 1 to 4, are offset to one another such that the hooking elements 1 in every other row are oriented aligned to one another in the transverse direction. It goes without saying that, depending on the application, other types of patterns of hooking elements 1 can be formed, both as relates to the hook shape and also orientation as well as dimensioning with respect to hook width, hook length, repetition frequency in the rows of hooks, and the like.
Patent Application
20100257704
