GB743337A - Improvements in or relating to control mechanisms - Google Patents

Abstract

743,337. Locking levers; controlling change-speed gearing. ROLLS-ROYCE, Ltd. Dec. 2, 1953 [Dec. 2, 1952], No. 30597/52 Classes 80(2) and 80(3) An operating lever 10, particularly for a vehicle steering column controlled change-speed gearing, is adapted to be moved in steps each step corresponding to an application of the operating torque. The lever 10 is mounted on a rod 12 for rotation with a radius arm 14. The arm 14 has a limited rotation. relative to a second radius arm 17 determined by pins 19 thereon and carries a roller 16 at its end which co-operates with a V- notch 21 in a pawl 20 pivoted on the arm 17. A blade spring 24 serves to urge the pawl 20 against the roller 16 and thereby centralise the arm 14 between the pins 19 of arm 17. Centralised on the pawl 20 between pegs 48 is a detent 27 with a nose 28 and acted upon by a blade spring 29. The detent 27, 28 is adapted to operate with a series of abutments 31-36 on a fixed structure 30. The arm 17 is secured to one end of a driven shaft formed in two parts 37, 38 connected by a lost-motion coupling 39, 40 and a rubber sleeve 41. To the other end of shaft 37, 38 is secured a toothed wheel 42 which co-operates with a spring-loaded locating plunger 43. In operation from the position shown, in which the detent 28 lies opposite one of the abutments 31-36, a torque is applied to lever 10 in the desired direction of movement and the arms 14 and 17 move together until the lost-motion between the shaft parts 37, 38 is taken up and the detent 28 moved out of line with the abutment 32. The arm 14 then moves relatively to arm 17 and roller 16 forces pawl 20 together with detent 28 outwardly. The arm 14 then engages one of the pins 19 and the two arms 14 and 17 again move together until the detent 28 abuts the next of the abutments 31-36, whilst the spring plunger 43 drops into the next tooth of the wheel 42. Further movement of the operating lever 10 by continued application of the torque thereto will not effect any further movement of the lever and arms 14 and 17. If the operating torque on lever 10 is released the arm 14 is then centralised with respect to arm 17 and detent 28 assumes a position opposite the abutment it was engaging. The mechanism can then be operated for a further step of movement. Dogs 46, 44 an the shaft 12 and arm 17 can be engaged for an overriding direct control of shaft 37, 38. A modified arrangement is described in which a pawl corresponding to pawl 20 is pivoted on driven arm 17 and carries two pegs which in any adjusted position are radially aligned with, and on either side of, one of a series of fixed abutments. These pegs are adapted to move radially, on an operating movement, for one of them to engage the next abutment and limit the movement to one step. The pegs are disengaged on release of the operating torque as before to allow a further movement.