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Injection Pump for Small Oil Engines

15th September 1944
Page 36
Page 36, 15th September 1944 — Injection Pump for Small Oil Engines
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A Résumé of Patent Specifications That Have Recently 4Ieen Published

THE problem of accurately metering small quantities of fuel probably sets a limit to the smallness of compression-ignition engines, so far as the standard injection methods are concerned. But a new principle may overcome this difficulty, and such a scheme is described in patent No. 562,826, by V. Stohanzl and the Birmingham Small Arms Co., Ltd., both of Small Heath, Birmingham. The pump described employs two plungers of differing diameters, arranged so that the total displacement is proportional to their difference.

Referring to the drawing, the co-axial plungers consist of an upper one (1) and a lower (2), the latter being slightly the larger. A distance piece (3) between the guides contains the inlet and discharge ports; these follow normal practice. • The two plungers work in unison, being joined by a thin central rod, and are reciprocated by a 'Snail-cam (4), acting through a rocker arm (5)_ As the left-hand side of the rocker descends, it permits the plungers also to descend under the pressure of their own springs (6); at the same time, a powerful spring (7) in an adjoining guide is compressed. During this time, the pumping space has increased its volume and has drawn in a charge of fuel. When the cam eventually releases the rocker, the plungers are snapped upwards by spring 7 and the differential volume of fuel is discharged .

The output can be adjusted by turning the pivot-pin of the rocker; this is made eccentric for the, purpose and is fitted with an external control.

BEAD-LOCKING DEVICE FOR TYRES l‘AUCH thought seems now to be al devoted to the problem of locking an outer tyre cover to its rim_in order. to prevent damage caused by deflation, and patent No. 562,643 shows a scheme of this nature from the Firestone Tire and Rubber Co., Akron, Ohio, U.S.A. Two designs are shown, one for one-piece rims and the other for rims having a detachable side wall.

The drawing shows a rim of the latter type with. the cover and-.tube in position. Located between the beads'is a spring-steel channel, member (1) of such dimensions that the tyre is'always' held in gripping relationship -with the rim, without assistance from inflation. The channelled ring extends completely around the rim, but the flanges are removed at two opposite points; this permits it to be worked between the

beads of the cover. A rubbed-channel (2) is interposed between the lock ring and the inner tube to protect the latter. It is preferred to make the. base of the beads, and the rim, slightly taper, as at 3, to assist the locking action.

To adapt the scheme to a one-piece rim, the lock ring is cut at one point, so that it can be sprung into a smaller diameter for insertion, later being expanded by a small latching device.

IMPROVED DRIVE FOR A ROTARY VALVE "r0 relieve a rotary valve of the one1 sided stresses imposed upon it by the driving gear is the object of a scheme shown in patent No. 562,933, by F. Aspin, 149, Walmersley Road, Bury, Lancs. The patent is of further interest, illustrating as it does the latest general layout of this inventor's engine.

In the drawing, the helical driving gear (1) meshes with the driven gear (2) which surrounds the stem of the rotary valve. The valve does not, however, carry gear 2, which is attached to a separate hub member journaled On a plain bearing (3) and a ball-race (4), The valve itself is a free-splined fit in she .hub, so that it is at liberty to settle itself in its seating unaffected by the driving stresses.

FEEDING OIL TO THE INDUCTION

ALTHOUGH the practice of feeding IlLa small quantity of oil into the induction system is not widely practised, there may, nevertheless, be certain advantages to be gained therefrom. A metering device for use in this respect forms the subject of patent No. 562,908, from E. Cox and P. Millwood, " Lodore," Boxhill Road, Tadworth, Surrey.

The main point of the invention is the flow-restricting device which governs the quantity of oil admitted. The drawing shows the induction pipe (1) fitted with the device, into which the oil arrives via end 2 and .first passes a gauze filter (3) after, which it flows through the restrictor (4) into the intake. The restrict& Consists of a screwed plug housed in a plain bore. so that the only fluid path is around the thread groove, , By fitting a plug of different pitch, the flow can be altered.

FROM General Motors Corporation, Detroit, Michigan, U.S.A., comes, in patent No. 562,809, particulars of improved bearing surfaces, specially suitable for heavy-duty service.

The patent refers first to copper rubbing surfaces bonded on to a steel backing, and the object is to prOduce a surface soft enough to embed any small foreign bodies that may in-trade. The machining operations tend. to work-harden the metal, and the essence of the processais that the bearing should be subjected•to an annealing operation. This ip carried out in an oxygen-free atmosphere, and may be conducted at the surpriSingly high temperature of 1,800' degrees F. (copper melts at 1,981 F.) for approximately one hour. This treatment also acts as a final test, faulty bonding showing up as a blister.

The patent also cOvers bearings of silver-copper-steel, . lead-copper-steel and other variants of the sathe nature. In every case 'the annealing temperature approaches closely 'to the melting point of the metal used.

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