Swash-plate Control of Epicyclic Gear Gives Infinite Variability
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AN interesting combination of two well-known principles is shown in patent No. 550,522 detailing an • infinitely variable gear. Epicyclic trains are employed in conjunction _with reaction members controlled by swashplate pumps. The patentee is R. J. Held, 1, Wherretts Lane, Elmdon Heath, Solihull, Birmingham. , On the engine flywheel is the annulus of the epicyclie gear, and there are two sun wheels and two sets of planets of markedly different diameters. By holding stationary, one or other of the two sun-gears," either of two ratios may be obtained between the input and output shafts. The-sun-gears are fixed, respectively, to rotary cylinder blocks (2 and 3). A number of pump plungers (4 and 6) slide in each block, the bores of one 'block communicating with those of the other. The distance of travel of these plungers depends en the angularity of two adjustable swash-plates (I and 8). In the position shown, block 2 is hydraulically locked, because swashplate 6 is square with the shaft, so that its plungers cannot travel in their cylinders and no fluid.ean therefore be displaced from the cylinders of block 2. One ratio is, therefore, in operation, block 3 meanwhile being idly rotated by its associated surhgear. If swash-plate 1 were square and swash-plate 5 inclined, the dther ratio would be in use_ Midway positions provide midway ratios, whilst if both swash-plates be given equal and opposite inclinations, the whole gear becomes locked and direct drive is established.
ROTARY-VALVE SEALING BY COMBUSTION PRESSURE
jN patent"No. 550,459, R. C. Cross, a pioneer of the rotary valve, and the Cross Manufacturing Co. (1938), Ltd., 33, Midford Road, Combo Down, Bath, propose a means for maintaining an
efficient_seal at the valve face. .
The cylindrical valve body rotates in a split housing, and the essence of the idea is that-the cylinder is free to move slightly, so that the compression and power strokes can cause extra sealing
force. • An accom
panying diagram sh.ows one application. of the principle. Portion 1 of the housing in which the valve (5) operates is rigidly fixed to the surrounding body of the engine, whilst the other half (4) is formed on the cylinder head. The cylinder isallowed a limited degree of rock about a pivot (2). Pressure between cylinder and piston tends to move the former in the direction of the arrow (3), and so to increase the loading on the valve at the precise moment when theagreatest sealing effect is needed.
NOVEL SELF-ADJUSTER IN FOURSHOE BRAKE
FROM Kirkstall Forge, Ltd., and F. R. Cowell, both of Kirkstall Forge, Leeds, comes in patent No. 550,348 a design for a self-energizing four-shoe 'brake with an automatic adjuster. The design is ate improvement on an earlier scheme shown in patent No. 542,112. By the use of four shoes almost a full circle of working face is provided. The shoes are floatingly mounted in pairs upon a pair of carriers (2). There is an expander (I) at the top (as drawn), and an anchor (i) at the bottom. This unit also forms a means for manual adjustment. The two sets of shoes abut on each other at top and bOttom, but
. at the sides they meet, stops (6) attached to the back-plate.'
In operation, the opening of the expander first brings the shoes to bear on the Urtma at the ends marked 3 and 7; then they move with the drum andmake contact over their full area. In addition to the two =mine pull-off springs; each shoe is fitted with its own retracting spring (4). The construction of the stops (6) is novel; they incorporate spring-loaded stepped wedge pieces (8). When the . slack in the " off" position becomes. excessive each wedge can advance and engage the shoe on the net step, an action which is repeated at intervals until the linings are completely worn out. Note the lip at the top of each step riser; which ensures clearance between shoe and drum after slack has been taken up,
WIDE PISTON RING TO SOLVE DESIGN PROBLEMS
("OE of the problems in connection 1/4./with the design of two-stroke engines of the port-controlled 'Variety is that of mutual interference.between piston rings and ports. Patent No. 550,206, from S. A. Adolphe Saucer, Arbon, Switzerland, shows a piston ring which will not only traverse port openings, but can also be permitted to emerge from the bottom end of the cylinder, thereby allowing a longer stroke for a given cylinder length. ' In an accornpanyieg sketch is shown a section of the piSton (3), the ring (2) and the cylindet wall (1), It will be seen that the ring is of channelsection, and is considerably wider than usual. Actually, it may be ,regarded as two spaced rings connected by a thin sleeve, althmigh the lower rim may be omitted in some cases, according to the specification..