Process and apparatus for mechanically joining metallic components

Abstract

A process for mechanically joining plies of thin metallic components lying on one another, and apparatus for its implementation, involves an impulse-wave conductor (9, 25, 31-35) having first and second substantially straight impulse-wave-conductor portions (19, 20, 32, 33) which are arranged at an angle to one another along which impulse waves are transmitted to a stamp (7) to be driven into a component to be joined by impulse force. The impulse waves are redirected between the first and second substantially straight impulse-wave-conductor portions by a structure of an intermediate angled portion (21, 31) located between, the first and second substantially straight impulse-wave-conductor portions.

Description

BACKGROUND OF THE INVENTION[0001] This application claims a foreign priority based on German application 100 10 340.5, filed Mar. 6, 2000, and the contents of that application are incorporated by reference herein.[0002] This invention concerns a process for mechanically joining (for example, clinching and stamping together) two plies of thin metallic components, such as sheet metal, lying on one another, and an apparatus to carry this out, involving a stamp of a joining tool being driven into a component to be joined by impulse force with the impulse force being transmitted to the stamp as impulse waves via an impulse-wave conductor. Examples of such processes and apparatus are disclosed in German patent document DE 197 77 267 C2 and European patent document EP 0 890 397 A1.[0003] In both of these publications a striking tool having an impulse-creating plunger, an impulse-wave conductor and a stamp are arranged in a row along a vertical axis. Thus, a rather tall structure results, s...

AI Technical Summary

Benefits of technology

[0007] By redirecting impulse waves, it is possible to arrange a striking tool to the side of, and substantially spaced from, a stamp, thereby resulting in a significantly narrower structure of the joining tool. Such a joining apparatus has fewer impractical "disturbing contours" and is comparable with a resistance spot welder tong in its operational possibilities, relative to its access to joining locations.

[0011] To increase the effectiveness of this version of the apparatus, it has proven to be beneficial to press a body mass on the reflection surface with a spring system, with a surface of the body mass lying on the reflection surface being larger than the reflection surface and extending beyond it in all directions and with a natural frequency of the spring-mass-system being half as great as the impulse wave frequency. This additional mass serves to ensure that a compression wave hitting the redirecting surface is mainly reflected as a compression wave and not as an expansion wave. In this regard, it is beneficial for the additional mass to be of a material that has a greater wave, or sound, resistance than does the impulse-wave conductor.

[0013] An air pressure driven plunger can be used as a striker of the striking tool. It is, however, particularly for reducing striking noise, beneficial for the impulses to be created by one or more lined-up piezoelectric actuators. This series arrangement of the actuators has the advantage of amplifying the magnitude of the striking, or impulse, amplitude so that a greater stamp path can be used. The piezoelectric actuators are particularly well suited for producing a pulsating striking force.

[0015] In a beneficial further embodiment of the apparatus of this invention, the impulse-wave conductors coupled to the stamp and die plate are structured as upper and lower tong arms of a shearing-principle support device of the joining apparatus. This embodiment makes possible a quite uncomplicated and low profile construction of the entire apparatus.

Problems solved by technology

Thus, a rather tall structure results, so that joining processes to be carried out by this apparatus cannot be done in operation areas that have limited space, although they are particularly well suited therefor.

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