GB225180A - Improvements in or relating to cut-out devices for groups of pneumatically operated switches - Google Patents

Abstract

225,180. Meyfarth, G., and Soc. Anon. des Ateliers de Secheron. Nov. 22, 1923, [Convention date]. Controllers, actuating, interlocking.-The cutout lever 21, Fig. 1, of an electric vehicle is arranged to open the individual pneumatically operated contacts 16, irrespective of the position of the controlling hand-wheel 20, the action of which is thereupon suspended until it is brought to its zero position. The arrangement is shown as applied to a single phase supply, in which the contacts on one side are connected to a tapped transformer and on the other side to the motor. Rotation of the hand-wheel 20 causes a nut 7 to be traversed along a screw 6, a cam 8 on the nut 7 sequentially lifting valve rods 10, thereby causing the corresponding contacts to close. Locking-rods 19 on each switch co-operate with lugs 9 on the nut. Movement of the lever 21 causes arms 22, 23 to turn about their pivots and depress a connecting-rod 24, which pulls the cam 8 downwards against the action of springs 27 and allows the contacts to open. Reverse movement of the lever 21 does not raise the rod 24 owing to a pin and slot connection 22<3>, 28, the cam 8 is therefore not returned to its operative position until the nut 7 has been returned to its zero position where it engages an arm 22<2> and turns the arms 22, 23 to their initial position. In the arrangement shown in Fig. 3, slow backward rotation of the wheel 20 causes the switches to operate in the normal reverse order, whereas quick backward rotation opens all the switches suddenly. The quick movement of the nut 9 causes a releasing lever 22 pivoted thereon to contact with a, locking rod 19, as the corresponding switch has not had time to operate and lift the rod 9. The lever 29 therefore withdraws a pawl 30 from a lock 31 which is urged to the left by a spring 35, and which by reason of cams 32 thereon pulls the cam 8 downwards. Thereafter it is necessary to return the nut 7 to its zero position so that the lock 31 contacts with a fixed stop 34 and is returned to its normal position. In two other arrangements the screw 6 and nut 7 are replaced by a rotating cam-shaft, which is axially displaced for effecting the sudden opening of the switches, the axial movement being imparted either by the lever 21 or by quick backward rotation of the hand-wheel 20. In a further arrangement using a cam-shaft, initial movement of the lever 21 effects opening of the switches and also mechanically disconnects the hand-wheel 20 from the cam-shaft, further movement of the lever 21 returns the cam-shaft to its zero position.