Patent GB-868205-A (GB)
Title: Speed control device
Inventor: TEETOR RALPH R
IPC: B60K31/06
Filed: 1958-02-03
Abstract: 868,205. Fluid-pressure servomotor control systems. PERFECT CIRCLE CORPORATION. Feb. 3, 1958, No. 3446/58. Class 135. [Also in Groups XXXI and XXXVIII The invention relates to a speed control device which may be set to hold an automobile at a predetermined speed by holding the accelerator pedal at such position as to produce said speed, the holding means being disabled by slight depression of either the accelerator pedal or the brake. The device comprises vehicle speed-responsive pressure means for advancing the accelerator pedal, manuallycontrolled valve means for limiting the advancing movement of the accelerator pedal by the fluid-pressure means to a position for operating the vehicle at a predetermined speed and manually controlled, electrically operated valve means for controlling said fluid pressure means. The accelerator pedal is connected to the threaded end 22 of a sleeve 15 mounted on a tubular piston-rod 14, the sleeve being connected to the piston-rod in a manner to cause advancing movement thereof. The piston-rod 14 extends through a pair of vacuum cylinders 12, 90 and carries a pair of slidable pistons 13, 91 having cup-like hub portions 43, 92 to allow telescoping. The space in the cylinder 90 below the piston 91 and the space in the cylinder 12 above the piston 13 have a communicating passage 95 and are maintained at atmospheric pressure. The hollow piston-rod 14 extends into a vacuum chamber 51 located at the upper end of the cylinder 90, the chamber being connected through a passage to the in-take manifold of the engine whence vacuum is supplied to the cylinder 12 through the tubular pistonrod 14 by way of radial openings 44. The openings 44 are opened or closed by means of a valverod 56, the openings being in communication with the interior of cylinder 12 when the valve rod has been moved downwardly by the action of a governor on the increasing speed of the vehicle. The valve rod 56 is connected through a linkage to centrifugal weights 66 rotatable and longitudinally movable on a shaft 73 driven through a flexible shaft 80 in timed relation with the vehicle speed by connection to the speedometer drive cable. Outward movement of the weights is opposed by a spring 81, adjustment of which to determine the vehicle speed is effected by a Bowden wire extending to the steering-post of the vehicle. At the lower end of the valve rod 56 a flange 57 is provided fitting within the piston-rod 14. Vacuum passes to the cylinder 12 when the flange 57 is below the openings 44. The lower end of the piston-rod 14 is vented to atmosphere so that when the flange 57 is above the openings 44, the cylinder 12 is in communication with the atmosphere. The admission of vacuum to the cylinder 12 causes the piston-rod 14 together with the sleeve 15 to be moved downwardly. Such movement of the piston-rod continues until the vacuum is cut off from the cylinder 12 by the closure of the radial openings 44 by the flange 57 of the valve rod 56. The cylinder portion 90 is adapted to have vacuum admitted to the upper end thereof to draw the piston 91 upwardly therein and movement of the piston-rod 14 together with sleeve 15 is effected by a snap-ring 93 fitting in a groove in the piston-rod and engaged by the cup-like huh portion 92. Valve means controlled by manually-operated electrical means for controlling the application of fluid pressure to the cylinder 90 comprises a valve 103 which forms the core of a solenoid 106, the solenoid being energized by current supplied from the battery through a push-button switch on the steering column. In the raised position of the valve, the passage 100 at the upper end of the cylinder 90 is connected with a passage 101 formed in the casing 10 and extending to vacuum chamber 51. When the solenoid is de-energized the spring 110 mounted in the upper end of the core forces the latter downwardly and passage 101 is closed, connection being established between passage 100 and passage 105 which communicates with the air cleaner of the engine. By cutting off supply of vacuum to cylinder 91, the vehicle is returned to normal running. Slight depression of the brake pedal opens a switch and breaks the circuit through the solenoid to cut off the application of vacuum to cylinder 91, the spring 110 forcing the valve 103 downwardly and separating the contacts 120, 121 on the solenoid. Slight depression of the accelerator pedal causes a switch embodied in the connection of the sleeve 15 and piston 13 to be opened to break the circuit to the solenoid. Slight relative movement between the sleeve 15 and piston-rod 14 causes opening and closing of the circuit.