Fully Automatic Chassis Lubrication
Page 44
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The We/son Selective Grease Injector, Which Constitutes a Development of the Group-nipple System
THE method of grouping grease nipples so as to simplify maintenance, as is widely employed on commercial vehicles, has been shown to have further possibilities by the introduction of an ingenious device which removes the need for the periodical grease-gun • " drill." This is known as the Welson fully automatic selective grease injector. The inventors and patentees are Messrs. W. Elliott and Son, 303, Mount Road, Levenshulme, Manchester, and we understand that they are prepared to grant a licence to manufacture on a royalty basis to responsible concerns. We are informed, also, that a large passenger-vehicle operating concern is carrying out a practical test with a view to the extended use of the device.
Simple and robust in construction, the apparatus has the merit of being easy to accommodate, and can be mounted on almost any part of the chassis. Principally it consists of a small hydraulic ram that is connected to the engine oil-pump, a grease container, and a distributing chamber, housing an automatic selecting device which directs a charge of grease to each of the delivery tubes at a time. The ram is caused to reciprocate by the rise and fall of the engine oil-pressure and a light return spring, whilst a moderate initial pressure is maintained upon the grease by a spring in the container.
is30 The oil pressure is tapped at some convenient place, such as the gauge pipe, and on starting up the engine, the consequent rise of pressure forces about 0.5 cubic in. of oil into the instrument, driving back the ram which in turn expels, at the other end, a charge of approximately 0.5 c.c, of grease.
A reduction of engine speed, with consequent fall in pressure, results in the oil being returned to the pump. This medium flows into and out of the instrument without being lost or consumed in any way and without affecting the normal working of the engine lubrication system.
A feature of the, system is that the greasing is effected while the vehicle is in motion and each minute charge is delivered to a bearing that is moving. Thus it is almost instantly circulated. Another point is the certainty and regularity of the operations, each bearing getting grease in constant sequence and at intervals frequent enough to prevent gumming up.
The degree of lubrication provided is in proportion to the amount of running and the instrument calls for no attention other than filling with grease.
The illustration—of a 30-point model —shows the grease container connected, by means of a ball-valve, with the pressure cylinder. This houses a twodiameter ram which boosts the pressure in a 3-to-I ratio, a 30-1b, oil pressure giving a 90-11). pressure on the grease.
Oil pressure, tapped at the gauge pipe, is applied to the large end of the ram, pressing a charge of grease against a piston which must move back before the charge is admitted to the distribution chamber. This piston carries a pawl which engages with ratchet teeth formed on the selector. The lastnamed blocks off every pipe but one. Each forward stroke of the piston drives the selector for a distance equal to one tooth and discloses the various delivery pipes one by one.,. Thus Successive charges are fed to each tube in turn, so that every tube in correct sequence secures a definite charge at full pressure.