Patent GB-1215331-A (GB)
Title: Traffic control barriers
Inventor: REINITZ WILLARD O
IPC: B61L29/02
Filed: 1968-05-13
Abstract: 1,215,331. Road barriers. RAILROAD ACCESSORIES CORP. 13 May, 1968, No. 22684/68. Headings E1G and E2M. A traffic control barrier includes a trafficblocking gate arm secured to a pivotallymounted gate-supporting means by way of a fracturable connector and is combined with a raising and lowering mechanism for the gate. The raising and lowering mechanism, Figs. 10 and 14, comprises a self-contained hydraulic assembly 29 with a hydraulic cylinder 49 having its lower end pivotally anchored by a removable pivot pin 51 to a flange 52. The cylinder 49 is mounted on a plate 55 forming a movable chassis for the entire hydraulic assembly 29 which is thus free to move about pivot pin 51. Secured within the hydraulic cylinder 49 is a piston 56 whose piston rod 57 is pivotally anchored by a removable pin 58 to a crank arm 59 attached to shaft 26. Extension of the hydraulic piston-cylinder assembly thus pivots crank arm 59 and shaft 26 about the axis of shaft 26 to raise yoke 23. The entire hydraulic assembly 29 may be removed by disconnecting the two pivot pins 51 and 58 and removing electrical plug connector 88 from its plug coupling 86. To raise the barrier, hydraulic fluid is pumped from reservoir 68 via pump 66, conduit 70, selector valve 71, conduit 72, manifold block 73, check valve 75 and conduit 76 to the lower end of cylinder 49. Return fluid flows from the upper end of cylinder 49 through a line filter 77, conduit 78, manifold block 73, conduit 79, an annular cavity in valve element 69 and check valve 81 to reservoir 68. The barrier is maintained in its raised position by check valves 75 and 83 which normally block the return flow of hydraulic fluid through lower supply conduit 76. To lower lower the barrier, the pump 66 supplies its output pressure to conduit 80 and thence to the upper side of piston 56 via valve 71 and conduits 79 and 78. Hydraulic fluid in the lower end of cylinder 49 cannot pass through conduit 76 because it is blocked by check valve 75, so it passes through the adjustable flow control valve 82 and solenoid valve 83 (which is now open) to the reservoir 68. After downward movement of the barrier is initiated, 'the motor 67 driving the pump 66 may be switched off and the barrier allowed to complete its descent under gravity; alternatively the whole descent may be .brought about by gravity. Cross-check valve 74 will only open if the pressure in conduit 73b exceeds that in 73a by a predetermined amount thus preventing a large build-up of pressure in conduit 73b if the decent of the barrier is stopped by an obstruction.  The barrier, Figs. 1 and 8, comprises a lightweight gate arm 21 joined by a break-away connector 22 to a forked yoke 23 having arms 24 embracing a pole 25 with their opposite ends firmly anchored to a shaft 26 passing through an actuator housing 27. The gate arm 21 is preferably made of telescoping, laminated resin segments having a generally rectangular, tubular cross-section, the segments 'being joined by bolts 40 or cement or cured resin. The break-away connector 22 (Fig. 8) comprises two interfitting members, a yoke plate 36 and a gate socket 37. Extending downward from the yoke plate 36 is a cylindrical pivotal hub 38 forming a base for a concentric elongated cylindrical connector post 39 having two diametrically opposite protruding radial ears 41. Gate socket 37 includes a cylindrical casing 42 having a central socket bore 43 with an internal diameter larger than the diametric dimension of the ears 41, but smaller than the diameter of hub 38, communicating with an enlarged portal bore 44 dimensioned to receive and pivot upon hub 38 when past 39 and socket bore 43 are telescopingly engaged. One or two ledges or ledge rods 45 extend across the socket bore 43 just above the position of the ears 41 in the telescopingly engaged position. The gate socket 37 is attached to the gate arm 21 by a plate 34 and to yoke 23 by shear bolts 48 passing through apertures 47 in tongue 46 and yoke plate 36. A collision of a vehicle with gate arm 21 will cause pivoting motion of the gate arm 21 about hub 38, thus shearing the shear bolts 48 and allowing the gate socket 37 to drop away from yoke plate 36 until ledge rods 45 rest upon ears 41. If the pivoting motion of gate arm 21 about post 39 continues over a sufficient arc, ledge rods 45 will clear ears 41 thus allowing the assembly of gate arm 21 and gate socket to drop away from the connector post 39 of yoke plate 36.