Patent GB-435498-A (GB)
Title: Improvements in brake mechanism for electric trolley buses and other vehicles
IPC: B60T13/74
Filed: 1934-06-09
Abstract: 435,498. Electricallyoperated brakes. RANSOMES, SIMS, & JEFFERIES, Ltd., and GILBERT, W., Orwell Works, Ipswich. June 9, 1934, No. 17173. [Class 103 (i)] Vehicle brakes are applied by an electric motor through a speed reduction gear, the motor current being regulated by movement of a pedal or hand lever which initsinitial movement engages a clutch disposed between the reduction gear and the brakes. Force applied to the pedal or hand lever may be transmitted to the brakes so as to be added to that applied by the motor. The shaft 1 of the motor 2 drives through a worm 3 and worm-wheel 4 keyed to a tubular shaft 7 mounted in bearings in the casing 5. The shaft 7 carries one member 10 of a ratchet clutch, the other member 11 being carried by a shaft 14 slidable within the shaft 7 against the action of a spring 30. The clutch member 11 has arms 12, 13 that are connected respectively to the front and rear brake gear. A lever 25, 26 freely mounted on the shaft 7 has the arm 25 connected to the pedal and the arm 26 connected to a bell-crank 361 pivoted at 37 and having a lug 39 for engaging a contact arm 33 freely mounted on the pivot 37. The arm 33 moves over resistance contacts 35. A quick make-and-break switch for the motor comprises a lever having a contact arm 43 pivoted to an arm 42 and normally held in alignment with it by a spring 441. The lever has a short arm 40 normally on the lower part of a stepped segment 41 of the bell-crank 36<1> but which in coming in to the upper part of the segment effects a quick movement of the arm 43. When the lever 25 is operated to apply the brake, the switch 43 is operated to complete the motor circuit and at the same time the lever 25 and shaft 14 are moved to the left to engage the clutch 10, 11 by the engagement of a roller 28 on the lever with a cam surface on the casing 5. Continued movement of the lever moves the arm 33 to gradually cut out the resistance and increase the torque of the motor. When the lever is returned to normal position the current is cut off and the clutch 10, 11 is disengaged to permit the return of the brake gear. Figs. 7, 8 show a complete equipment in which however the clutch member 11 has a single arm 13. To enable the pressure on the pedal 44 to be applied to the brakes, this arm is connected by link 54 to an arm 55 pivoting freely on a short shaft 56 and engaging by projection 57 an arm 58 which, as shown, is connected by link 59 to the arm 60 of the master cylinder 61 of a hydraulic transmission system by which the brakes are applied. To enable the pressure on the pedal 44 also to be applied to the brakes it is connected by link 64 to a second arm 65 freely mounted on the shaft 56 and arranged to engage the lever 58. Operation of the lever 25 of the motor device by the pedal is effected by an arm 46 on the pedal-shaft 45, having a cam surface engaging a roller 49 on a lever 50 pivoted at 51 and connected to the arm 25 by an arm 52 and a link 53. After the motor has been fully put into operation the roller rims on an arcuate part 48 of the cam lever.