Patent GB-476606-A (GB)
Title: Improvements in and relating to control devices for valves and other apparatus
IPC: G05G5/02
Filed: 1936-06-13
Abstract: 476,606. Variable-speed gear. BONN, C. R. H. June 13, 1936, No. 16553. [Class 80 (ii)] [Also in Groups XXIX and XXXVII] An actuating device for valves, electric motor switches, and other apparatus, comprises means for locking the valve against movement to a new position to which it tends to move under an independent load until the control member reaches the new position when the locking device is released to permit the valve to follow the control member to the new position where it is again locked. The Figures show the invention applied to the control valves of a fluid operated control device for a variable-speed gear. In the form shown the load is applied to the spindles 46 of inlet and exhaust valves 24, 25 by fluid pressure admitted to one side or other of a pair of meshing gear wheels 68. The shaft of one valve has an extension 61 carrying a bracket 61A formed with a pair of arms 64 parallel with the axis and pair of radial arms 65. Two members 66, 67 are pivoted to the arms 64 and are acted on by springs bearing against the arms 65, to press a catch projection 62 on the member 66 into one or other of a series of locking recesses in a ring 55 fixed to the casing and a " pick-up " pin on the member 67 into engagement with a recess 93 in a movable member 84. The control member 73 is formed integrally with a disc 74 provided with a series of peripheral notches 75 adapted to co-operate with a spring-pressed pivoted locking catch. This disc has a pair of diametrically opposed arms 77 to which are pivoted members 79,. 80. The member 79 carries a roller 63 adapted to track over a cam surface 56 formed on the ring 55 while the member 80 carries a pin 91, adapted to cooperate with a member 84 slidably and rotatably mounted on a boss formed on the control member 73. Mid-way between the arms 77 the disc 74 is provided with a third arm 78 carrying a roller 87, engaging a groove 86 in the member 84 and a roller 115 engaging a groove in a member 114 slidably mounted on the spindle 61. The member 84 has recess 93 adapted to receive the " pick-up " pin 70 on the member 67 and a cam depression 90 adapted to co-operate with roller 92 on the catch member 66. When the control member is operated to move the valves from one control position to another the first part of the movement moves the roller 63 off a high part of the cam, this movement transmitted through an adjustable pin on an extension of the member 80 moves the pin out of engagement with the member 84. Rotation of this member by the roller 87 and the engagement of the cam recess with the roller 92 moves this member axially to follow the pin 91 and release the recess 93 from the pin 70. During these movements the spindle 61 is held against rotation by the catch member 62, but as the control member reaches a new position the roller 63 passes on to a high part of the cam which action presses the pin 91 against the member 84 which in turn acts on the member 66 to release the catch whereupon the valves move to their new position under the influence of the load. In a modification particularly applicable to the control devices described in Specification 476,604 wherein the loading pressure falls when the gears are in the neutral position, the recesses 90, 93 and the cam track 57 are modified so that after leaving the neutral position the " pick-up pin is not disengaged from the recess 93 but is carried round by the flange 88 and thereby rotates the spindle 61 so as to close valve ports and effect a rise of pressure. Specification 418,505 also is referred to.