GB852629A - Device for change-over of variable drives - Google Patents

Abstract

852,629. Change-speed control. VOITH G.m.b.H., J. M. Feb. 11, 1957 [Feb. 9, 1956], No. 4666/57. Class 80 (2). At least one shaft, e.g. the input shaft 10, of a change-speed and/or reverse gear on a rail vehicle, controlled by dog-clutches, e.g. 42, is provided with a rotation-detecting feeler 11, 12, which permits a change to occur only when the shaft 10 is stationary, additional means being provided for moving the feeler out of contact with the shaft when the latter is rotating, thereby preventing unnecessary wear on the feeler. In the reverse gear shown, freely mounted wheels 44, 45, which can be clutched to the input shaft 10 by the dog clutch 42, mesh wheels 70, 72 (the latter through an idler) fast on an output shaft, not shown. A selector lever 1. operates valves 2, 7 permitting compressed air to flow from a supply 4 to pipe lines 6 or 8. With the selector lever in the forward position V as shown, compressed air is directed via the pipe 6 to the cylinder space 9 of the feeler 11, and to the normally closed control valve 18. If the shaft 10 is rotating, the feeler 11 is deflected thereby, and a piston 14 allowed to travel to its upper posi. tion which uncovers a port 15 allowing the compressed air to flow through pipes 161, 47 to a chamber 35 at the left of a selector locking piston 32. The space at the right of the piston 32 has meantime become filled with compressed air via passages 16, 21, 30 and balances the force exerted on the piston which remains in the locked position by virtue of the spacing 33. If however the shaft 10 is stationary, the feeler 11 is not deflected and the piston 14 does not move sufficiently to uncover the port 15. The pressure build up on the right hand side of the piston 32 moves the piston and locking rod 34 to the left, disengaging notches 48 and opening valves 19, 25. The compressed air is allowed to flow through the duct 17 to a pipe 39 to operate a piston 37 which engages the forward gear train. Rotation of the shaft 10 will then deflect the feeler 11 to lock the selector piston in its newly engaged position. For reverse drive a second feeler device 28, 12 and valves 7, are provided for similar operation. Non return valves 22, 50 prevent the passage of compressed air from the forward to the reverse system and vice versa. A single feeler and piston common to all paths and controlled by non-return valves may be used. The additional means for moving the feeler out of contact with the shaft 10 when the latter is rotating is shown in Fig. 3, which is an enlarged detail view of one feeler 112 and its shaft 110. Such means comprises a pin 159 on the feeler 112, which pin, when the feeler 112 is deflected by contact with the rotating shaft 110, eventually rides over one or other end of a gap in a fixed sleeve 158 surrounding the shaft, to lift the feeler 112 clear of the shaft at the limit of its deflection.