Abstract: A cartridge assembly for a travelling wire electrode electrical discharge machining apparatus includes a cartridge barrel having a first open end and a second open end, and a wire guide mounted in the first open end of the cartridge barrel for guiding the wire electrode. A current pick-up holder is mounted in the second open end of the cartridge barrel and includes an index pin for engagement with a current pick-up. A current pick-up is provided for delivering current to the wire electrode, the current pick-up being mounted in the pick-up holder and including a longitudinal bore for engagement with the wire electrode. The current pick-up includes a first end and a second end, with a tool engagement portion located at the first end of the current pick-up for engagement of a tool to rotate the current pick-up relative to the current pick-up holder. An index pin receiving portion is located at the second end of the current pick-up for receiving the index pin of the current pick-up holder.

Abstract: A connector bank with two rows of insulation displacement contacts for connecting insulated conductors, in particular of cables for telecommunication and data systems, comprising a surge arrester magazine to be inserted into the connector bank. In order to provide a connector bank having a voltage surge protection and allowing connecting and disconnecting as well as testing the attached cable conductors at the insulation displacement contacts even with inserted voltage surge protection, the two rows of insulation displacement contacts are arranged on different sides of the connector bank. An insulation displacement contact of the first row is connected over a connecting element with an insulation displacement contact of the second row. The surge arrester magazine is arranged laterally approximately centrally between the two rows of insulation displacement contacts.

Abstract: An air heating apparatus comprises a auxillary PTC heating element in an air duct lying parallel to the length of the duct to define first and second air passages separated by the heating element. The PTC heating element has apertures through which passes air to be heated; the two air passages thereby communicating with each other by means of the apertures through the heating element. First and second valves are located at upstream and downstream ends of the first and second air passages for selectably closing and opening the upstream and downstream ends of the first and second air passages, respectively.

Abstract: Addition of between 2 and 20% by weight of noise suppressing constituents to a conventional d.c. air-carbon arc cutting and gouging electrode results in an electrode operating at noise levels between 5 and 15 dbA below that of a conventional d.c. electrode. Further noise reduction is achieved by lowering the operating pressure of the air in the torch.