GB1017830A - Power transmission device - Google Patents

Abstract

<PICT:1017830/C1/1> <PICT:1017830/C1/2> A double friction clutch comprises a double-faced driving member mounted for rotation with a shaft having rotatably mounted thereon two driven members selectively axially engageable with the driving member. In a glass heat treating machine wherein glass sheets 10 are conveyed slowly through a heating chamber 12, rapidly through a secondary heating chamber 13 and the first part of a tampering chamber 14, where the sheet is rapidly cooled by air jets 16, and slowly through the remainder of the chamber 14, the conveyer rollers are driven by a motor 32 through two-speed belt gearing. A countershaft 41, driven by the motor, has keyed thereto a splined driving sleeve 94 carrying a pair of clutch plates 90, 91 secured together by an internally splined clamping member 98. Two pulleys 62, 63 mounted on bearings 121, 122 on the shaft 41 are rigid with electromagnetic field pieces 58, 59 energizable through slip rings and brushes 80, 81 and 86, 87 respectively to attract the clutch plates 90, 91 to couple the respective pulley to the shaft. The pulleys 62, 63 are connected by bolts to <PICT:1017830/C1/3> <PICT:1017830/C1/4> pulleys 64, 63 on a shaft 42 driving the conveyer rollers at either of two speeds. The desired speed may be manually selected by a change-over switch 75, or may be selected automatically by a light beam 172 sensing the leading edge of the sheet. With the conveyer moving at low speed switch 162 (Fig. 5) is closed to actuate a relay 155 to energize clutch winding 59; as the edge of the sheet cuts the light beam 172 the switch 162 is opened and switch 163 closed to trip the relay in the opposite sense to engage the clutch 56 and accelerate the glass sheet. A similar arrangement is used to decelerate the sheet in the tempering chamber 14. In a modified clutch, the plates are made in four sectors riveted to a flexible diaphragm rigid with the countershaft 41.