An Engine Governor
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1-'-flE operating forces in a centrifugal I governor vary as the square of the speed, whereas the return springs follow only a linear law; this means that governors usually have a limited range unless complex correcting mechanism be incorporated. A new design, claimed to be better in this respect, comes from
the Hoof Products Co., 6543 South Laramie Avenue, Chicago, Illinois, U.S.A. (Patent No. 702,951.)
The drawing shows one of several types described in the patent. The centrifugal weights (1) when moved outwards slide a collar (2) to the left• against the force of tension springs (3). The disposition of these springs is the essence of the patent; they are placed at an angle as shown.
The angle varies with the position of the thrust collar, which means that the spring rate increases with the spindle speed and gives a good approximation to a square-law response. The patent gives graphs showing thrust-collar movement plotted against load, and the resulting curve is very near to being straight.
A UNIVERSAL JOINT FROM DAIMLER-BENZ AN improved type of flexible joint is shown in patent No. 704,041 (Daimler-Benz A.G., Stuttgarf-Unterturkheim, Germany). The main feature is the use of a ball joint at the centre to ensure concentricity.
The drawing shows a section of the assembly which includes the usual pair of spiders bolted to the flexible disc. One spider is provided with a central hub (1) whilst the shaft on the other side is extended to form a cylindrical nose-piece (2).
A34 A part-spherical ring (3) is placed on the nose, and is surrounded by a halfsocket formed in the end of the central hub. The other half of the socket is formed by a ring (4) which is springloaded on to the ball.
The ball is thus made self-adjusting for wear and yet has a measure of axial freedom. It is filled with lubricant and sealed by a rubber washer (5) which is squeezed when the flexible disc is bolted up.
THE LATEST IN PISTON-RING DESIGN
PATENT No, 703,282, comes from J. Howlett, A. Woolcott and Wellworthy Piston Rings Ltd., all of Radial Works, Lymington, Hants. It describes the latest proposals in the design of rings for use in chromiumplated or stainless-steel liners, and is claimed to minimize scuffing.
The drawing shows an enlarged section of the ring which is assembled from various units. At the bottom of the groove is a wavy spring-ring (1) which expands the assembly against he cylinder wall. Member 2 is another wavy spring which spreads the other rings into intimate contact with the upper and lower walls of the groove. Split steel rings (3 and 4) are placed under the spring ring, whilst above it is another pair of split rings. The upper one of these (5) is made of steel but the other (6) is made of bronze, preferably one with 10 per cent, of tin. In the event of the lubrication becoming poor, the bronze ring is said to deposit microscopic fragments on the cylinder wall and so save the rest of the rings from scuffing.
A CYLINDER-HEAD LAYOUT TO house an overhead exhaust valve and two overhead inlet valves in a convenient and practical manner, is the chief feature of a cylinder-head disclosed in patent No. 703,281, by Lanova A.G., 16 Bahnhofstrasse, ZUrich, Switzerland.
A plan view of the head is shown in the drawing in which 1 is an air-cell, 2 the combustion chamber and 3 the injector. The exhaust valve is located in the combustion chamber, whilst the two inlet valves (4) are at the side.
The inlet passages are at first separate, but merge in a gentle sweep to meet
the main induction pipe. The two valves are operated in unison by a common rocker engaging a bridge over the two stems.
THE REGULATION OF SINGLEPLUNGER INJECTION PUMPS A METHOD of regulating the output ti of a single-plunger, multi-outlet injection pump is shown in patent No. 703,785 by Daimler-Beni A.G., Stuttgart-Untertfirkheim, Germany. The object is achieved by advancing or retarding the rotation of the plunger as it reciprocates on its pumping stroke. Referring to the drawing, the plunger (1) is reciprocated by the camshaft (2) and is at the same time revolved by a helical gear (3). At its upper end, it is provided with a sloping groove (4) which opens the discharge path to each of the outlets (5) in turn. The fuel is drawn in during the suction stroke via a one-way valve located in passage 6. To regulate the output, the plunger gear (7) is raised or lowered by a bellcrank, not shown. The effect is to advance or retard the plunger by causing it to rotate relative to its helical driving gear. The groove in the plunger is shaped so that commencement of injection is not affected by the advanceretard motion, all the variation occurring at the moment of cut-off.