GB592993A - Improvements in gearing for converting rotary motion into variable reciprocating or variable oscillating motion - Google Patents

Abstract

592,993. Cam gearing. MELDRUMS, Ltd., and WRIGHT, A. N. June 5, 1945, Nos. 14083/45 and 3550/46. [Class 80(iii)] [Also in Groups XXX and XXXVI Cam and follower gearing for converting rotary into a variable stroke reciprocating or oscillating motion is described in relation to an underfeed stoker for feeding solid fuel to a furnace. A main driving motor drives a shaft 31 and a feed screw 18 through worm and wheel gearing 36, 35 and fuel is supplied from a hopper 22 to the screw 18 by means of a reciprocating feed tray 24. The reciprocating motion of the tray 24 is derived from a lever 54 which is oscillated by the engagement of a follower 48 in an endless cam groove 46 on the shaft 31. This cam groove is formed by two sleeves 42, 43, the sleeve 42 being fixed to the shaft by a cross-pin 44 and the sleeve 43 being axially adjustable on a key 45 so as to vary the width of the groove to introduce lostmotion into the drive whereby the stroke of the reciprocating tray 24 is varied which thus varies the rate of feed of the fuel from the hopper. The delivery end of the tray 24 is formed with spaced fingers 28 which prevent the passage of larger lumps of the fuel to the screw 18 and deliver them to a chute 29. The axial adjustment of the sleeve 43 is effected by means of a guide member 57 with a flat surface 59 and side flanges 60, Fig. 4, which allows free rotation of the sleeve 43 and is adjustable axially of the shaft 31 by means of an eccentric 65 and a sheave 61 engaging between the flanges 60. The adjustment of the eccentric thus varies the rate of feed of the fuel to the furnace and this adjustment may be effected automatically according to conditions associated with the furnace, such as steam pressure or water temperature, by a reversible electric motor 66 (see Group XXXV). In the event of the fuel feed being stopped completely the main driving motor may also be stopped by an auxiliary switch. The application of the gearing to a furnace stoker of the sprinkler type is also referred to in which an intermittent rotation of the fuel measuring shaft is effected and made variable by a clutch operated by the follower from the adjustable cam groove.