Patent GB-1078844-A (GB)
Title: Improvements in windscreen wipers
Inventor: HADEKEL RUBEN
IPC: B60S1/12
Filed: 1963-04-16
Abstract: 1,078,844. Windscreen wipers. TRICO-FOLBERTH Ltd. April 15, 1964 [April 16, 1963; April 23, 1963], Nos. 14881/63 and 15981/63. Heading A4F. [Also in Divisions F1 and F2] A windscreen wiper motor system comprises two hydraulic motors 2, 4 driving separate wiper spindles arranged in series, the master motor 2 operating a control valve 8 causing the supply of fluid to the motors to reverse direction whenever the master motor 2 reaches the end of its wiper stroke in either direction, the slave motor 4 controlling a valve 23 which establishes a bypass across the slave motor when it reaches the end of its wiper stroke in either direction, so synchronising the wiper motors. As shown as the wiper motor pistons move to the right fluid from inlet pipe 16 passes via pipe 12 to drive slave motor 4 the fluid expelled from motor 4 passing via pipe 6 to drive master motor 2 from where fluid is expelled via pipes 10, 14 to a reservoir. At the end of the stroke, arm 17 engages lever 18 to move piston valve member 20 to the right, to reverse the direction of fluid flow so that the motors move to the left till arm 21 moves piston valve member 20 to the left (the Fig. 1 position) thus causing the motors 2, 4 to reciprocate. To park the motors operating member 22 is moved to the left so that at the end of a motor stroke to the right lever 18 does not engage and move piston valve member 20 to reverse the motors, which are thus parked. On restarting the movement to the right of member 22 and lever 18 causes piston valve member 20 to move, to again cause reversal of flow. When master motor 2 moves to its parking position its arm 31 engages lever 32 to open unloading valve 34 to by-pass the motor to prevent further movement by by-passing fluid from pipe 6 to a reservoir via exhaust line 35. As valves 25 and 34 are spring-loaded the residual pressure holds the motors in a parked position. Synchronization of the motors is attained by slave motor 4 operating valve 23 at the end of its stroke to the right when its arm moves piston 24 allowing liquid to by-pass it via pipe 43, non-return valve 25, pipe 29 and pipe 28 so that main motor 2 if it lags may finish its stroke. Should main motor 2 lead slave motor 4 on this stroke is must lag behind it on the return, when similarly synchronization in the reverse direction through non-return valve 26 may be effected. Alternative embodiments are described in which a single spring centred two way piston valve (Fig. 2) replaces the valves 23, 25, 26 and other forms of master motors and unloading valves (Figs. 3 and 4) including combined master motors and by-passing unloading valves (Figs. 5 and 6) are disclosed. Thus (Fig. 5) the piston (52) of the master motor has a spring loaded valve (53) closing a passage way (54) through the piston. When the piston moves to the motor parking position at the extreme right, projection (58) abuts the wall (59) so opening the passage way (54) whereby fluid may flow from one side of the piston (54) to the other for discharge to the reservoir. Tension spring (60) provides for the maintenance of some residual pressure to keep the motor piston locked in the parking position. Alternatively (Fig. 6) fluid may be supplied to the right hand side of a hollow piston and piston rod (64) through a sleeve (63) and openings (66) therein, the two sides of the piston being put into fluid communication via apertures (68) in the sleeve (63) which are opened against the action of spring (69) as the piston and piston rod (64) move to their extreme right hand parking position. The drive from the reciprocating piston (72, Fig. 7) of the windscreen wiper motor is transmitted to the oscillating shaft (83) of the wiper spindles by a transmission system comprising a pinion (70) which is driven through an arc of 180‹ about its axis (75) by a rack (71) attached to the piston (72). An arm (77) adjustably positioned in a guideway (78) in the pinion transmits this motion through a pin (76) and link (79) to a pinion (82) which is held in engagement against a rack portion of the link (79) by a saddle (80). The pinion (82) is mounted on the shaft (83). By this arrangement sudden accelerations of the rack (71) are converted to smooth accelerations of the pinion (82), whilst at the ends of the arc of pinion (82) when inertia forces needed to move the wipers are greatest, the force transmited from rack (71) to pinion (82) is also greatest. By adjusting the position of arm (77) in guideway (78), the stroke of the arc of movement of pin (76), and thus the angular movement of pinion (82) and the arc of wipe if the wipers may be varied as required. A clockwise rotation of pinion (70) causes a clockwise rotation of pinion (82) but if the pinion (70) is assembled on its axis (75) 180 degrees displaced or if arm (77) is inserted in guideway (78) from the other end so that pin (76) is positioned the other side of axis (75), then a clockwise rotation of pinion (70) causes a anti clockwise rotation of pinion (82). Hence the wipers may be arranged to park at either end of their pivotal axis.