Commer Introduces Articulated Tractor-trailer Outfit
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J-type Automatic Gear Used for the First Time on Normal Type of Tractive Unit Machine
QHORTLY to be made available against M.O.W.T. licence . to
• acquire. is a Commer-Hands 6-84on articulated tractor trailer .outfit, which represents. the latest'. addition to the Conirner range of vehicles.
An interesting feature about this new machine is that it incorporates, for the first time, the well-known Karrier 1-type automatic detachable coupling gear and retractable trailer fore. carriage, a familiar and well-recognized assembly of the original Karrier mechanical horse, • • The advantages of this System, hitherto, available in connection with more or less lOcal or " inner zone " -,transport, are nOw extended for longdistance operation. Attachment and detachment are carried out without the need for the ,driver leaving his seat, there being a hand lever in the cab for effecting decoupling. Coupling-up is automatic, the tractive unit simply being reversed on tracks reasonably in line with the semi-trailer.
Regarding the latter, there are two
types which have been designed and produced by Hands (Letchworth), Ltd. The first is a 6-tonner, and is available with a 15 ft.-long. by 7 ft. 3 ins.-wide platform body or, if required, with 18-in, detachable sides. The 8-tonner measures 18 ft. or 20 ft. lorurr6, as required, by 7 ft. 3 ins, wide, and can be supplied with or without drop sides.
The brakes on the semi-trailer are of the Girling two-leading-shoe type, and are operated by a vacuum servo in conjunction with the brakes on the tractive unit. A spare wheel and tyre can be supplied with the 8-tonner as an'extra, if required.
In connection with this outfit, the popular 10 ft. wheelbase Commer Superpoise vehicle forms the tractive unit, of which the following is a general specification. It has a six-cylindered petrol engine having a total cylinder displacement of 4,086 c.c., and gives 80 h.h.p. It gives a torque of 178 lb.-ft. and, for taxation purposes, it is rated at 27 h.p.
From the engine the drive is taken by an 11-in, single dry-plate dutch, to a four-speed gearbox providing ratios of 1.0, 1.788, 3.366 and 6,94 to 1 forward, and 8.246 to 1 reverse. The gear ratio of the standard rear axle is 7.44 to 1.
The drive from the gearbox to the rear axle is taken by a balanced tubular propeller shaft having Layrub universal
joints; spiral-bevel gears are used in the rear axle. Frame side members have a section of 8i ins. by 2126 ins, by lag in., there being five cross-members to form the bracing. Spring dimensions are, front 36 ins. by 21 ins., and rear, 4-6 ins. by 3 ins.
All four wheels of the tractive unit have Cowdray-type brakes with Lockheed hydraulic actuation. Initial movement of the brake pedal partially opens a vacuum servo control valve to apply the brakes to the semi-trailer wheels, and further pressure serves to increase the braking 'effort and to apply the ' brakes to the wheels of the tractive vehicle. The brake shoes on the Superpoise measure 14 ins. by 2i ins, at the front, and 16 ins. by 3 ins, at the rear. The 4.33-in. by 20-in, steel disc wheels are equipped with 32-in, by 6-in. heavyservice 'tyres, twins, of course, being provided at the rear.
The lighting and starting equipment operates at 12 volts, the battery being of 63 amp.-hr. capacity. In addition to a five-lamp set, an electric horn is included. A Lucas compensated-voltagecontrol dynamo supplies the current.
Regarding the cab, this is of steel construction and has a Diaflex mounting. It has a one-piece windscreen, fullopening winding windows and self
closing doors which are forward-hinged to assist in reversing.
' Respecting the maximum allowable gross-laden weights of the outfits, for the 6-thriller the figure is II tons and on the 8-tonner 12i tons.
• The price of the tractive unit— chassis and cab—complete with Jtype coupling gear is £560; with 15-ft. platform body the 6-ton semi-trailer costs £206, and with a drop-sided body, £227. In the case of the .3tonner, with 18-ft. platform body, the price is £244, or £264 with drop sides. Respective prices of the 20-ft. bodied semi-trailer are £250 and £273. The maker is Commcr Cars, Ltd., Luton.