| 摘要 |
952,707. Making electrical contact points. FANSTEEL METALLURGICAL CORPORATION. May 7, 1962 [May 8, 1961], No. 17554/62. Heading B3A. [Also in Division B5] A method of producing electrical contact discs, for use as contact points, from a rod of contact material comprises rotating the rod, bringing the rod and a line cutting device into cutting relationship and effecting relative movement between the device and the rod in a plane at an acute angle to the axis of the rod to cut it along substantially one half a chordal length at the depth of cut. A rod 3 of tungsten or other refractory metals is supported in a motor driven spindle housing 2 by a collet 4 and fed to a stop 12 by pneumatic or other means (not shown). Mounted on the same base as the rod assembly is a cut off wheel drive assembly comprising a motorized spindle 17 on which is mounted a thin fibre or steel disc cut-off wheel 14, a housing 18 slidably mounted on table 16 pivoted at 15 and an hydraulic motor 26 which swings the table 16 about the pivot 15, the axis of which intersects the axis of the rod 3 at right angles. To cut off discs having conical end faces the table assembly 16 is disposed and locked at an angle less than 90 degrees to the rod axis and the wheel assembly 14 fed towards the rod 3 by an hydraulic motor 19 to cut off the end disc and produce a conical face on the end of the rod and a concave face on the cut-off end face of the disc. The subsequent cutting-off of the following disc produces one with a conical and concave end faces. Discs with two conical ends are produced by displacing the axis of the wheel 14 one half of a wheel diameter in a plane perpendicular to the plane containing the axes of the wheel and rod or by using a releasable collet for holding the end of the rod in contact with the step 12 until the wheel has travelled the full diameter of the rod to cut a conical face on the back of the severed disc. To produce a spherical radius on the rod the cut-off wheel assembly angular relationship with the rod is continuously varied up to 90 degrees. The contacts may be finally tumbled to produce rounded edges as necessary. Alternatively an oscillating saw blade may be used. |
