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24th February 1925
Page 30
Page 30, 24th February 1925 — A NEW AUTOMATIC CLUTCH.
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A Resume of Recently Published Patent Specifications.

A NEW form of clutch is described in the specification of

Louis Renault, No. 212,521. The object of this invention appears to be the provision of a clutch which will release itself automatically should the resistance to the drive be more than the torque being developed by the engine at any given speed, and thereby prevent a driver from stopping his engine through not having changed down to a sufficiently low gear, or not having his engine running fast enough to develop the necessary, torque. At first sight the drawings may convey the idea that there are a great number of working parts, but it must be borne in mind that in ordinary running all ,parts revolve as a solid mass ; consequently, there is but little wear on any part.

At a low speed the engine can revolve without imparting movement to the car, as the two shoes which form the grip of the clutch will he in the position shown in Fig. 2, and will be dear of the drum (11). When a predetermined speed of engine is reached the weights (7) fly outward and, by means of the shaft (6), will impart movement to the sector (8) and through its teeth to the boss of the left-hand wheel (16) of the balance gear shown. The effect of this is to move the casing of the balance gear (13), and through its links (14) to apply pressure to the shoes (5), forcing them against the drum (11) and causing a clutching effect. This clutching effect causes the engine shaft to carry with it the drum (11), which, through the springs (12), drives the driven shaft (2) and through it drives the car. So far this describes the driving effect, but it is obvious that a balance gear, or differential, cannot act by moving one of its side wheels only, as no movement would be imparted to the casing unless there were some resistance to movement applied to the opposite side wheel (17). Here we come to a point which it is not easy to make clear in the space available. It will, however, be seen that the shaft (1) ends where it meets the boss of the drum (11), and that the driven shaft (2) commences at this point. Both shafts are provided with a hollow in which the members (18) and (20) can slide, and with slots for the pins (19) to slide in, as shown in Fig. 5.

The bosses of both the side wheel (13) and the drum (n) are provided with helical slots as shown in Fig. 5. Stout springs (12), as shown in Fig, 4, connect the drum (11) to the plate (10), and, through it, drive the car. Should these springs be overloaded and be extended beyond a predeter mined distance, a movement will take platebetWen 11 and 10 which will result in the sliding member (18) being "pressed towards the member .(20) sliding within the driving shaft ; this, in turn, causes a slight rotary movement of the side wheel (17) around its shaft by means of the helical slots. This movement is arranged so that it causes the side wheel (17) to move in such a direction that it causes the shoes to release their grip of the drum, and brings about a declutching action due to overload. Thus it will be seen that the side wheels of the balance gear are governed—one by the speed at which the engine is running and one by the resistance offered to the torque of the engine. "

The specification says; "By suitably adjusting the tension of the springs (9) and (12) it is thus passible to cause declutehing only when the speed is such that the driving torque is equal to or greater than the resisting force ; as soon as it becomes less, the action of the wheel (17) preponderates and declutching will take place automatically, warning the driver that he should either increase the speed of the engine, if it has not reached its maximum torque, or decrease the speed of the vehicle by using a lower gear. Another form is shown in which the same principle is applied to a multi-plate clutch.

The arrangement around the sliding members as shown in Fig. 5 appears to us to be very slight and unsuited for hard work, but probably the actual form shown should be only looked upon as diagrammatical. .

Silent-running Ball Bearings.

IT may not be generally known that even the noise arising from a ball bearing when running at high speed is audible above the other noises of a motorcar, particularly in the case of dynamos and magnetos.

It is true that this trouble is more acute in high-class pleasure cars than in commercial vehicles, but the commercial vehicle is fast approaching the pleasure car in refinement, and noisy ball bearings may very soon be objected to. It is recognized that noise in a bearing can only arise from the fact that the tracks or races along which the balls roll, art not formed with a perfectly smooth surface. The grinding wheels with which they have, hitherto, been finished leave a series of minute hollows and projections, which, althoug'h not measurable, are sufficient to produce vibrations which Set up the whirring noise one hears when a ball bearing is spun.

H. S. Wood and the Rudge-Whitworth Co., Ltd., in specification No. 227,277, describe a process they have developed which imparts to the race the same perfect polish that one sees on a ball. The process described consists of treating both the inner and, outer rings of the bearing to the same polishing to which the balls are subjected. That process consists of placing the parts in a revolving barrel with a number of balls slightly smaller than those which will eventually fill the bearing, together with a polishing medium. The polishing effect operates on all surfaces of the ring at the same time, so the hole is left slightly smaller and the. width slightly greater. An amount of .002 of an inch is removed from all surfaces by the polishing process.

A New Fuel for Internal-combustion Engines.

WHAT is described as a new fuel for internsd-combustion engines is the subject of a patent by B. H. Morgan, No. 225,685.

The inventor claims to have discovered that if petrol in certain quantities is added to certain mixtures of alcohol and ether, the rate of distillation of such mixtures between temperatures of 60 deg. and 90 deg. C. is higher than the rate of alcohol and ether alone, and that a very advantageous fuel is thereby obtained. The proportions named are : alcohol, 60 to 30 parts; ether, 30 to 60 parts, and the remainder petrol.

TWO-STROKE engine, in which the charge, instead of

being compressed into the crankcase, is taken into a chamber which is provided between the underside of the piston and a dividing plate separating the cylinder from the crank ease, is described in specification No. 221,532, by T. F. Smith.


People: Louis Renault

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