GB779647A - Improvements in or relating to power-assisted steering gear for mechanically propelled vehicles - Google Patents

Abstract

779,647. Vehicle power steering. BISHOP, R., and JOHNSTON, R. H. Dec. 11, 1952 [Dec. 11, 1951], No. 29013/51. Class 79(5). Power-assisted steering gear for mechanicallypropelled vehicles comprises a piston and cylinder motor supplied with pressure fluid under the control of a valve 44, Fig. 1, the closure member 43 of which is moved axially on relative rotation occurring between parts 1, 2 of the steering shaft. Part 1 carries a flanged part 12, cup-shaped members 17, 18 and an end member 13 held together by bolts 14 for rotation with the shaft part. Part 2 is keyed to a disc member 19 rotatable relatively to member 17 and having clearance holes 24, Fig. 2, for the bolts 14, springs 26 acting through T-shaped parts 27 to centralise the bolts in the holes. Part 2 carries a flanged member 32 rotatable relatively to member 18 and having axial slots 34, Fig. 3, in its flanges 33, and member 18 has helical slots 35 in its wall 18b. A pin 36 engages each pair of slots 34, 35, the latter slots being wide enough for rollers 37 mounted on the pins, and the pins engage a block 39 rotatable on part 2 and an annulus 41 which rides in a slot 42 in the valve closure member. Thus, if on rotation of part 1, springs 26 are overcome, member 18 will turn relatively to member 32 causing axial movement of annulus 41 and member 43 in the appropriate direction. The resulting movement of the motor and road wheels acts through shaft part 2 to centralise the valve member. If the power supply fails, steering is effected manually by engagement of the bolts with the sides of the holes in member 19, if the steering effort overcomes the springs 26. Specification 745,202 [Group XXIX] is referred to.