Patent GB-773804-A (GB)
Title: Travelling excavators, cranes or the like supported upon endless tracks
Inventor: HALL PETER
IPC: E02F9/22
Filed: 1954-08-10
Abstract: 773,804. Motor vehicle driving and steering gear. RANSOMES & RAPIER Ltd. Nov. 8, 1955 [Aug. 10, 1954], No. 23271/54. Classes 79(2) and 79(5). The invention is concerned with a travelling excavator, crane or the like comprising a carriage 1 supported on endless tracks 2, 3 and rotatably supporting a superstructure 4, the tracks being driven by sprockets 11 from a common transverse shaft 8 on the carriage, the shaft 8 being driven from a prime mover 110 on the superstructure through a shaft 5 disposed in the axis of rotation of the superstructure, and clutch and locking mechanisms associated with the sprockets for manoeuvring and operating purposes. The invention comprises pneumatic or hydraulic devices 28, 29, 36, 37 mounted on the carriage for controlling the clutch and locking mechanisms, selector valve apparatus 40 for controlling the supply of operating fluid to the mechanisms and a single fluid pressure supply line leading to the devices from a pressure source on the superstructure and including a vertical conduit 54 coaxial with the shaft 5. As shown, each track sprocket 11 is supported by a shaft 13 splinedly carrying a sleeve 15 having at its ends dogs 17, 21, adapted to be engaged respectively with dogs 19 secured to the carriage 1 and dogs 23 secured to the shaft 8 whereby the sprockets can be selectively braked, driven or, when the sleeves 15 are in a neutral position, permitted free rotation. The sleeves 15 are connected to pivoted levers 33, 34 interconnected by a spring 35 urging the sleeves into theirsprocket-driving positions. The levers 33, 34 are selectively moved by the pneumatic devices 36, 37, and a disc on the shaft 8 carries teeth 25, Fig. 2, adapted to be engaged by ratchet members 26, 27 under the action of the pneumatic devices 28, 29 to lock the shaft 8 against rotation in one or both directions. The devices 28, 29, 36, 37 are supplied with compressed air from the superstructure 1 through boxes 53, 55, the conduit 54, a flexible conduit 41 and the selector valve apparatus 40. The apparatus 40, Fig. 3, comprising a housing carrying valves 44 . . . 47, one for each device, and each valve has a control element connected to a roller 48, the rollers being engaged by a movable control member 42 having cam formations 43. The member 42 is connected to a bellcrank lever 56 to the conduit 54 which is vertically movable within the shaft 5 for actuating the valves 44 . . . 47 and hence the devices 28, 29, 36, 37 to cause (1) engagement of both clutches and disengagement of the ratchet members, (2) engagement of either clutch with the other sleeve 15 moved to its locked position, and (3) engagement of both clutches with either or both of the ratchet members operative. In another embodiment, Fig. 4 (not shown), the selector valve apparatus may be additionally or alternatively controlled by a sleeve between the conduit 54 and the driving shaft 5. In a further embodiment, Figs. 5 to 7 (not shown), it is possible to engage the clutch of one sprocket and leave the other sprocket free to rotate in order to give turns of large diameter. In yet another embodiment, Figs. 8 and 9 (not shown), the devices 28, 29 are operated individually. As shown in Fig. 10, the prime mover 110 on the superstructure is connected by forward and reverse friction clutches 111, 112, which can be both disengaged to form a main clutch, gearing 113, and a dog clutch 114, 115 to the driving shaft 5. The conduit 54 is vertically moved to control the selector valve apparatus by a lever 118 carrying inclined cams 119, 120, which operate valves 121, 122 in circuit, Fig. 12 (not shown), with pneumatic rams for operating the clutches 111, 112 to prevent either of the latter clutches being engaged when one or other of the ratchet members 26, 27 is operative. In a modification, Fig. 13 (not shown), the ratchet members are prevented from being engaged unless the clutch 114, 115 is engaged, a manual override being provided for parking. In another embodiment, Fig. 14 (not shown), the selector valves are associated with a solenoid electrically connected through conductors surrounding the conduit 54 to slip rings which are connected to an electrical supply through switch mechanism.