Device for producing a loop on one end of a coil spring

#This application claims priority to German Patent Application No. 10 2010 014 353.7 filed on Apr. 9, 2010, which is incorporated herein by reference in its entirety.

#The invention relates to a device for producing a loop at the end of a coil spring, with a gripping unit with gripper jaws for retaining the spring in a processing application.

#Devices for producing a loop at the end of a coil spring are, as a rule, positioned before a leg spring machine, wherein the spring is prefabricated, i.e., wound or bent, whereby the prefabricated spring, before the cutting of the wire, is gripped by the grippers of a gripping unit of the device, is fed to a loop producing device after the cutting and the second loop produced at the end of the spring. The first loop at the beginning of the spring is already produced in the spring machine. However, in principle, such devices for affixing of a loop can be coupled with any kind of spring machine.

#In the following, the invention is further explained in principle by way of example with the help of the drawings:

#FIG. 1 shows a perspective view of a device, according to the invention, with a tool designed as bending block for the “pulling up” of the loop;

#FIG. 2 shows a perspective view of a device, according to the invention, with a tool with positioning plate, with which the forming of the loop through “bending up” is effected;

#FIGS. 1 and 2 show the perspective depictions of a device 1 for the loop manufacture at the end of a coil spring, whereby FIG. 1 shows a tool for “pulling up” of the loop and FIG. 2 a tool for “bending up” of the loop.

#For a more detailed depiction of the design in the device 1, FIGS. 7 to 10, which show the essential parts of the device 1 in various stages of the loop manufacture in perspective assignment to each other, shall first be expanded on. Initially, the device 1 comprises a gripping unit 2, which exhibits two folding gripper jaws 3, which are designed to hold one coil spring 4 at a time. The embodiment of the gripping unit 2 with gripper jaws 3, as shown in FIGS. 7 to 14 is only a preferred embodiment of a gripping unit, which can be utilized in the device 1. Of course, another form of the gripping unit 2 with differently designed gripper jaws 3 can be applied. The gripping unit 2 with the gripper jaws 3 is movable in the longitudinal direction of the device 1 along a direction of travel a in order to, e.g., grab the springs 4, in combination with a leg spring machine 5, in said machine and subsequently move them in the device 1 to the processing position or any other desired position, as shown in FIG. 15. The processing position of the gripping unit 2 can be seen in FIG. 1 as well as FIGS. 8 to 10, and 12 to 14. In FIG. 2, the gripping unit 2 has also reached the processing position but is not visible due to the perspective covering by other elements.

#The coil spring 4 held by the gripper jaws 3 is exactly aligned with its central axis A (see FIG. 8). In this alignment it will subsequently be processed with other tools in the processing position. As can be best seen in the basic side views of FIGS. 3 to 6, the coil spring 4 protrudes in the direction of its axial extent over the gripper jaws 3 (in the Fig. depictions: upward) at least by a sufficiently large enough section of an end turn, which allows for a certain travel underneath and therefore gripping by the bending tool for upward bending. The remaining part of the spring body 7 is held tightly within the gripper jaws 3 of the gripping unit 2.