Power-controlled Steering for Tracked Machines
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, CRITICISMS of the usual clutch-andbrake method of steering endlesstrack vehicles are contained in patent No. 539,079 from H. Bounsall, of the 96th Battalion, Royal Tank Regiment,
A Résumé of Patent Specifications That Have Recently Been Published
whose assertion is that the existing system is inaccurate in use, and liable" to excessive wear.
The patent describes his suggested improvements, which are shown here diagrammatically. The main shaft (4) drives, via bevels, a cross-shaft upon which are mounted sunpinions (3) which drive the track sprockets via an epicyclic reduction gear. So far, the driving mechanism is complete, provided that the planet carriers and associated • spur gears (6) are held from rotating.
These carriers are normally balanced one against the other by a differential mechanism. Actually there axe two differential gears having a common worm wheel, and the
• two sets of bevel pinions (1) are locked together on common spindles. The inner set of bevels on the shafts (8) is geared to the planet carriers (6), whilst the outer set carries a pair of brake drums (2) normally held by their bands.
By rotating the worm wheel via,the worm shaft (7) and releasing one• of
• the brake bands, one side or the other is caused to lose its drive at a controlled rate, without gearing-up the drive to the other side, as usually happens. The steering is thus brought under delicate control.
Shaft 7 may be power-driven via a clutch (5), and always revolves in the same direction; it is the selection of one brake drum or the other which decides the direction of steering.,
SIDE AND TAILBOARD RETAINING BOLT CROM the Ford Motor Co., Ltd., and
J. Whitby, both of SS, Regent Street, Londot, W.1, comes in patent No. 539,045 an improvement in locking bolts for the sides and tailboard of a drop-sided lorry.
A side view of the body is illustrated, 1 being the drop side; the tailboard is not directly shown, as it is positioned behind the corner pillar (6). Tail-board and side carry bars (5" and 2 respectively) which can be engaged by a sliding bolt (4) mounted on the corner pillar. The bolt can be pulled down to release the sides, and held by the end being hooked under stops (3). In one position the side is released ; in the other the tailboard. Adyantages include robustness, certainty of locking and absence of loose parts that are liable, to be lost.
EXTENSIBLE BODY FOR MOBILE WORKSHOP
A BODY designed for a mobire workA—t shop is described in patent No. 539,090, by Charles H. Roe, Ltd., and W. Davies, both of Crossgates Carriage Works, Leeds. The patent is based on the method of obtaining increased body space when the vehicle is stationary.
Shown in an accompanying drawing are a rear view and a section of the bOdy in the open and closed positions. The sides consist of doubly hinged flaps (1 and 2) which open sideways to form first the floor and roof extensions, and then, hingeing again upwards and downwards to meet at a mid-point, the wall (4 and 5). To support the extensions. sliding girders (3) are pulled out along slides on the frame.
The machinery generally is attached to the permanent main floor, the extra space giving room for the operators to work.
UNIT-PRINCIPLE DEPTH CONTROL
TOprevent variations of the effective depth in operations suCh as ploughing is the object of a control scheme shown in patent No. 539,003, by David Brown Tractors, Ltd., Meltham Mills, Huddersfield.
The drawing shows the rear of a tractor coupled to ploughing tackle. A groundengaging wheel (5) forms the depth stop, and is mounted on an arm (4) pivoted on the frame of the plough. The angle of this arm can be adjusted by means of a screw-jack (3) placed within easy reach of the driver. To permit the motion the plough frame is coupled to the tractor by a pair of pivoted parallel links (2 and 6).
A further feature is a power-operated lifting gear for raising the whole Implement clear of the ground ; this consists of an hydraulically worked arm (1) attached to the parallel links, and under the centrol of the driver. • The links, of course, do not normally carry any weight.
• We included' a. general description of this apparattis and a fuller explanation of its functioning in our issue dated January 14, 1941.