Patent GB-1296148-A (GB)
IPC: B60T11/10
Filed: 1970-02-19
Abstract: 1296148 Brake locking mechanisms S KIMURA 19 Feb 1970 [19 Feb 1969 12 May 1969] 8107/70 Heading F2F A motor vehicle has brakes operated by a foot brake pedal 10, a foot brake locking mechanism 15 for locking the brakes in the brakes applied position and means for releasing the locking mechanism, the latter including apparatus connected with the pedal 10 and which locks the pedal when the pedal is actuated and an electrically operable mechanism associated with the apparatus to operate the latter. The electrically operable mechanism is connected to a powersource 42 by means of an electric circuit which is completed before the electrically operable mechanism causes the brakes to lock. The electrical circuit includes a plurality of switches each having co-operating contacts which are engaged to complete the circuit, the switches consisting of an ignition key switch 68 the contacts of which are engaged when the ignition key 76 is in the vehicle "NO" position and separated when the key is at other than that position, a switch 58 connected to the vehicle gear shift lever 59 and having contacts arranged to be engaged when the lever is shifted into a vehicle non-driving gear and separated when the lever is shifted into a vehicle driving gear, a switch 62 responsive to the position of the brake pedal, the contacts of which are closed when the pedal 10 is depressed, and a switch 52 mechanically connected with the locking mechanism and having contacts which are caused to be mechanically engaged by the locking mechanism when the latter is de-activated and which are caused to be disengaged by the mechanism when the mechanism is activated, whereby once the mechanism is activated the contacts of the switch 52 separate and the circuit is broken thereby preventing unneeded power loss and premature deterioration of the electrically operable mechanism, whereby when the contacts of all of the switches are engaged the locking mechanism 15 is activated to lock the pedal 10 in the brakes applied position. As shown, master cylinders 12, 13 operated by the foot pedal 10 are connected to a fluid switch 15 that includes a check valve 17 normally open to allow fluid flow to and from the master cylinders, and locking of the foot brakes is effected by depressing the pedal 10 to close the stop light switch 62 whereby the solenoid 24 is activated to shift the lever 25 of the switch 15 to the left and to close the valve 17, return of fluid to the master cylinders being prevented. There are switches respectively comprising a gear shift lever switch 58 whose contacts are closed when the gear shift lever 59 is placed in one of the non-drive gears, e.g. neutral or park, a manual switch 56 engageable by the vehicle operator and an inertia controlled, e.g. a mercury switch 55, whose contacts are normally closed by acceleration of the vehicle but are opened by sudden deceleration and stopping of the vehicle whereby the solenoid is activated to shift the switch 15 to a brake locking position. Foot brake locking release is effected by turning on the ignition switch 68 to start the vehicle engine, placing the gear shift lever 59 in a drive gear and depressing the accelerator pedal 185 whereby the solenoid 152 is energized to shift the lever 25 to the solid line position so that brake fluid can return to the master cylinders 12, 13, the release means being deactivated when the lever 25 engages a switch 176 to de-energize the solenoid 152. An optional inclined surface rollback prevention switch means 182 includes a gravity controlled switch 302 in electrical parallel with a vacuum switch 304 connected to the vehicle induction manifold and which is closed to complete the circuit through the switch means 182 to prevent waiting for a pressure decrease in the manifold to release the foot brake; the switch means 182 is not closed until the vehicle engine is driving the vehicle uphill with sufficient force to prevent rollback of the vehicle. The parking brake comprises a pull shaft 202 biased to the release position by a spring 204 and provided with ratchet teeth engaged by a pawl 208 in the brake engaged position, which is secured to or forms part of a solenoid 212. By turning on the ignition switch 69 to start the vehicle engine and engaging one of the driving gears, while the parking brake is on, and moving the accelerator pedal 185 the solenoid is energized to retract the pawl from the ratchet teeth and thereby release the parking brake.