GB545176A - Improvements in apparatus for loading sheath wire electric heating units - Google Patents

Abstract

545,176. Electric heating elements. BRITISH THOMSON-HOUSTON CO., Ltd. July 25, 1941, No. 9437. Convention date, July 25, 1940. [Class 39 (iii)] Apparatus for' loading sheathed wire heating units with insulating material comprises means for feeding the insulating material into the sheath, centralizing means to hold the resistance wire in central position, which means is reciprocated during filling. The centralizing device engages the insulating material on its downward stroke, whereby the turns of the resistance wire are slightly lifted to counteract sagging. The feed of material is slowed when the sheath is partly full, and cut off when full. The sheath 11 containing the heating wire with terminals attached, as in Specifications 144,767 and 198,932, [both in Class 39 (iii)], is mounted on a base 29, and the upper end held by jaws 69. The carriage 52 and associated parts are then lowered by means of a knob 58 until the centralizing tube 48 passes down into the sheath to the bottom. During this movement roller 68a engages latch 43 to release lever 38 to drop into its lower position on the latch. Lever 114 is then depressed, whereby a mercury switch 172 is closed to start a vibrator 167 which imparts periodic blows to the sheath to compact the insulation. Simultaneously, or preferably previously, the rotary driving shaft of the apparatus is started. The latch 107 is also released to open a shutter which allows insulating material to flow from the hopper 93 into the upper end of the sheath, and the latch also releases a detent which allows pawl 148 to engage ratchet wheel 146. This effects the vertical oscillation of centralizer 48. On the downward stroke the centralizer engages the insulating material and is temporarily released by slip between the pawl and ratchet 148, 146. The centralizer is gradually elevated as the insulating material rises, lifting the carriage 52 until the attached cam 118 actuates the shutter control to decrease the flow of insulating material, whereby a more uniform density throughout the length of the sheath is obtained. The apparatus continues to function until another part of the cam 118 acts to shut off the flow. At the same time, a wedge 59 rises and is held by levers 63 whereby the centralizer is allowed to drop and hold the upper terminal. The operating lever 114 is returned to its initial position, which also closes the shutter and de-energizes the vibrator. The jaws 69 are opened, and the filled sheath can be removed.