Patent GB-1487935-A (GB)
Title: Apparatus comprising a rescue appliance
IPC: E06C5/40
Filed: 1974-10-23
Abstract: 1487935 Luffing arm apparatus MAGIRUSDEUTZ AG 23 Oct 1974 [17 Nov 1973] 45876/74 Heading B8H [Also in Division F2] Apparatus which comprises a rescue appliance such as an extensible turntable ladder 4 or an articulated boom (20), Fig. 3 (not shown), mounted on a vehicle 1 also comprises a mechanism for levelling the appliance when the vehicle is standing on uneven or sloping ground. The appliance 4 is rotatable about a rotational axis 5 which, when the appliance has been levelled, is vertical and includes a horizontal axis 3 about which the ladder 2 or boom (20) is swung during erection. The levelling mechanism comprises a first (upper) intermediate member 9 and a second (lower) intermediate member 10 which are in the form of wedge-shaped discs, the member 9 being attached to the appliance 4 by an anti-friction bearing 12 which permits rotation of the member 9 relative to the appliance 4, and the member 10 is attached to the vehicle for rotation relative thereto about a vehicle axis 8 by means of an anti-friction bearing 13, the members 9, 10 being connected by a third anti-friction bearing 11 so that the members 9, 10 are relatively rotatable about the axis 7 of the bearing 11. The axis 7 makes an angle α with the axes 8 and 5 for all relative positions of the members 9, 10. The maximum angle of slope at which it is possible to effect levelling of the appliance is 2α, and at such angle it is necessary to rotate one of the members 9, 10 relative to the other member through 180 degrees, the actual member rotated depending on the direction of ground slope (as shown in Figs. 2, 3, not shown). For angles less than 2α one of the intermediate members is rotated through less than 180 degrees to effect levelling of the appliance, after which both members 9, 10 can be rotated together to adjust the position of the appliance relative to the axis 5. In the embodiment of Fig. 4 (not shown), the members (9, 10) are interconnected by a plain bearing (11), the bearing (13) between the lower member (10) and vehicle also being a plain bearing. Fig. 5 (not shown) discloses an embodiment in which the lower member of the levelling mechanism comprises a plate (23) having an upwardly projecting boss (24) whose axis makes the angle (α) with the vehicle axis (8), the upper member (25) comprising a bore (26) which is rotatably seated on the boss (24), the plate (23) and member (25) being formed as inner raceways of anti-friction bearings whose outer raceways are attached respectively to the vehicle and the appliance. In Fig. 6 (not shown), the levelling mechanism comprises first, second and third anti-friction bearings, the outer race (12) of the first such bearing being attached to the appliance, the upper intermediate bearing being formed by the inner (31) and outer (33) races of the first and second bearings while the lower intermediate member is formed by the inner races (34, 36) of the second and third bearings and by an intervening tubular member (35). Fig. 7 (not shown) shows an embodiment of levelling mechanism which is also formed by three anti-friction bearings. In Fig. 8 (not shown) the levelling mechanism is formed by four concentric rings, the second ring (43) having a rib (45) disposed at the angle (α) relative to the horizontal. In all of the embodiments described the rotation of the intermediate members may be effected either manually, or automatically by means which includes a power drive between the appliance and one intermediate member, a power drive between the two intermediate members and a power drive between the other intermediate member and the vehicle. Locking means (not shown) may be provided to lock the intermediate members for simultaneous rotation, or to lock the appliance and one intermediate member against rotation while the other intermediate member is being rotated.