| 摘要 |
397,573. Track apparatus for stopping trains. BRITISH POWER RAILWAY SIGNAL CO., Ltd., GLENN, S. L., and PIERCE, E. E., Windsor Works, Slough. March 14, 1932, No. 7564. [Class 105.] Apparatus, such as a train stop, having an arm moved from a normal to a reverse position by an electric or other motor driving a pinion which climbs up an arc-shaped rack on the movement of the parts to the reverse position and travels down the rack during the gravity or spring restoration to normal is locked against any external forcible movement of the arm to the reverse position by providing on the pinion a short untoothed portion which lies opposite the lower part of the arc-shaped rack when the parts are at normal and a locking means fixed on the pinion and adapted in the final stage of the return movement to normal to engage with a means in the mechanism casing thereby to prevent upward forcible movement of the pinion ; this looking means is automatically released when the motor is set in motion for the purpose of setting the arm to the reverse position. The Figure shows the relevant parts of a train stop mechanism as described in Specification 286,362, [Class 105, Railway signals &c.], modified in accordance with the present invention. The train stop is moved to reverse, on energization of the motor, by the motordriven pinion 3 climbing up the rack 8 and is returned to normal by the gravity descent of the motor and pinion 3. In the full normal position the pinion 3 presents an untoothed portion 200 to the rack 8 and inserts a cross bar 201 of a stirrup piece 204 beneath a fixed lug 202 so that external forcing of the train stop, which would necessitate the pinion 3 rising, is prevented. On energization of the motor the rotation of the pinion 3 first removes stirrup bar 201 from beneath the lug 202 and thereafter the teeth of the pinion engage the rack 8 to effect the climbing. Any person having authorized access to the interior of the mechanism casing can move the stop manually to the reverse position by a handle 210 on the the stirrup piece 204. The rack 8 is capable of a slight movement and to position it correctly in the full normal condition the stirrup 204 is provided with a second bar 212. An alternative locking means consists of a cheek fixed on the pinion and formed with a cam to engage a corresponding cam on the rack member. |
