| 摘要 |
Two telescoping tent poles can be clamped together in a certain position relative to each other by means of a clamping screw and a thread part being fastened to the wall of the outer telescopic tube 2. The thread part is formed as an internally hollow rivet 5, the collar of which can be received internally in the pole 2 in an outwardly protruding indent 7. Externally on the pole 2, a pierced disc 8 is placed on the neck of the rivet 5, and the rivet is kept in place by clamping action between the collar of the rivet and the pierced disc 8 on the tube wall, when the rivet material above the pierced disc 8 has been clenched. Subsequently, a thread is cut internally in the hollow rivet. The rivet is clenched and the indent 7 is made by drawing of the tube material in the pole 2 by means of a lower tool in the form of a mandrel 10 having slightly smaller diameter than the internal diameter in the pole 2, and an upper tool. The upper tool has four concentrically placed punches, innermost a centring punch 19 being able to hold the rivet 5 in place on the lower tool; around the centring punch a riveting punch 22; second from the outside a disc holding-down clamp 23; and outermost a drawing muff 26. When the rivet 5 is centred, the pierced disc 8 is caught by the disc holding-down clamp 23, following which the indent 7 is made by drawing the material by the drawing muff 26. Simultaneously, the collar of the rivet and the pierced disc are bent to follow the contour of the tube wall. Thereafter, the rivet material is clenched by the riveting punch 22. The pole 2 is removed from the tool, and an internal thread is cut in the rivet 5. The thread part has a nice look and is reliable, simple and cheap in manufacture. <IMAGE>
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