A New 30-cwt. Straker-Squire Machine.
Page 19
Page 20
If you've noticed an error in this article please click here to report it so we can fix it.
An Interesting Model Which Will be Staged Both at Bristol and Olympia.
We recently inspected the new 30-ewt. machine made by Sidney Straker and squire, Ltd. This model is designated by its makers as a C. W." type. The power-unit consists of a tour-cylinder vertical engine, of which. the cylinders are cast en bloc, and are provided with ample-sized water-jackets which, owing to clean design, should oiler no restriction to the thermo-syphon circulation of cooling employed. The bore is 90 mm. and the stroke 120 mm., the engine developing 20 b.h.p. at 1000 r.p.m. Conforming to recognized good practice, the valve pockets are all cast on one side of the engine—the near side in this case—the valves themselves being interchangeable. Provision has been made for tappet adjustment and the whole of the valve mechanism is enclosed by two separate cover-plates, either of which can be quickly detached.
The Lubrication System.
The crankshaft is made of specially-selected high-tensile steel, and it is provided with five bearings, one between each crank. Considerable attention has been given to the lubrication throughout the chassis. In the case of the engine, lubrication is automatic. The crankshaft bearings are pressure-fed by means of a gear-pump and oil-leads to the underside of each bearing. The pump also ensures a constant oil level to suitable troughs cast inside the crankcase, for allowing splash lubrication to the connecting rods, each of which is provided with a special form of dinper. An oil telltale. together with a sight glass, is fitted on to the dash.
Details that Count.
The camshaft and magneto are driven through helical gearing. The magneto, which is a Bosch high-tension " ZU4 " type, has the drive transmitted by means of a dogclutch, so that whenever this fitting is replaced, correct timing is as sured. The ignition is advanced or retarded by means of the usual form of finger lever placed on the steering wheel. A very neat form of button-switch is fitted at the top of the steering column. The clean run of the induction piping impressed us favourably, as also did the manner in which the intake mixture is exhaust-heated. In place of a costly form of "shark's jaw" or jacket clipped round the exhaust pipe, and connected to a bulky hot-air tube having badly-designed bends, a small copper pipe connects an annular space cast round the mixing chamber directly with the engine exhaust. The car buretter fitted is the company's own Ware type. Both foot accelerator and hand-control throttle are provided. Power is transmitted to the gearbox by means of an ample-sized leather-faced cone-clutch. Adjustment is provided for taking up the clutch leather. The gearbox is provided with three speeds, which are controlled by a gate change. The gearshafts are mounted upon ball bearings.
The Final Drive.
The main drive is transmitted by means of cardan shaft and worm gearing. The worm wheel is of hard phosphor-bronze, the worm itself being steel ease-hardened. Two alternate ratios of final drive may be fitted, 7.2 to 1, or alternately, 9 to 1. The housing at the centre of the rear axle is designed to accommodate either ratio, The back axle itself is a robust job. and consists of a one-piece forging. Swaged out at the centre, it forms a housing for the worm and differential, which gear, as a unit, may be removed from the top side of the axle for inspection. i he differential shaft is or the floating type, and therefore takes the drive only. The drive to the rear road wheels is taken by a. circular flange, forged integral with each differential shaft at the outer ends, which registers with a similar flange on the road wheel. The two are coupled together by means of four bolts, which are strengthened where the sheering stress renders it advisable. Upon taking out the four nuts on each rear wheel, the differential shaft may be withdrawn without having to jack up the road wheel. The pressed steel frame calls for mention as being particularly well-designed and constructed. Metal machining strips are provided for ensuring perfect alignment of engine and gearbox, The turning circle of the machine is 40 ft. The internal-expanding brakes operated by both foot and hand both take effect on the rear road wheels. The drums are each fitted with a cast-iron liner.
The tire sizes, single fronts and twin rears, are 800 ram. and 90 mm. in each ease. This model has been designed, we understand, to meet the requirements of a delivery van capable of carrying a load of 30 cwt. The leading dimensions of the machine are :— Wheelbase ... 10 ft. 6 in.
Overall length ... ... 16 ft. 0 in.
Overall width ... ... 6 ft. 4 in. Length behind driver available for body 8 ft. 3 in. Approximate height of frame from ground when loaded ... ... 2 ft. 6 in.