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17th August 1920, Page 28
17th August 1920
Page 28
Page 28, 17th August 1920 — A NEW FOUR-SPEED GEARBOX.
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A Résumé of Recently Published Patents.

. A new gearbox particularly adaptable as a four-speed unit has been: ,patented by S. Bramley-Moore, the specification being numbered 145,827. Apart from the reverse gear, all the wheels necessary -for this box are six in number, and, as might ' be anticipated, the gearbox itself is remarkably compact for one affording so many changes of gear. Another advantage of the box is that there is no necessity to manipulate the change-speed gear lever when changing from boat to second or third to fourth speed or vice versa, this being aceanialishest merely by the operation of declutching or clutching The addition of a further intermediate gearwheel, such as is usually necessary for the reverse, affords, it should be noted, two changes of • speed in the reverse direction. The inventor particularly thaws attention to the fact that this invention is applicable-in the ease of a, four. speed has only, or at least that four is the motimum number of changes which can

be provided. e Our illustrations show, in one, a section of a t-ypical gear-box embodying the invention, mid in the other, the gear's and clutches depicted aia,grammatically in the

four principal pesitions. In the latter illustration those parts which are shaded are the ones employed in transmitting the power for the particular gear shown. The four diagrams show respectively the first, second, third and fourth speeds. It" is perhaps important to draw attention to the fact that the arrangement of the shafts on the diagrams is opposite to that in the detail drawing of the box.

The friction clutch is a clouble•-cone, ore. There is a cone bolted to the engine flywheel and with it engage two clutch members, one an the interior surface another on the exterior. These two members are fastened together in such a way that they move to and ire) as one unit under the influence of a clutch pedal and only one of them can be in engagement at one time.

The interior clutch member is keyed to a long shaft, which is spigotted at one end into the engine flywheel, and traverses the whole length of its -box, being seigottecl at its Other end in a hollow driven shaft. The outer chi,sh member is keyed to n aleeve bearing on the first-named shaft, which is referred to as the primaias shaft, the sleeve we are now discussing beiter called the secondary shaft. This sleeve terminates just inside the gearbox in a toothed pinion. arise to

this pinion, within the box, and keyed. to the primary shaft, is another pinion slightly larger than the first. It haa clutchkteeth .formed on that face of it farthest removed from the friction clutch.

The driven shaft, which, as we have stated, is hollow, and in which is spigotted the outer end of the primary shaft, bears at its inner end against this gearwheel and is also splined to receive a third wheel which again is larger than the other two. This third wheel has also clutch teeth formed -upon it of such dimensions that they will engage with those on the wheel of the primary shaft. There is a layshaft in the box to which are keyed three gearwheels. These are of such dimensions that they are capable of being enmeshed 'with -the wheels of the primary, secondry, and driven shafts. Two of them are in continuous engagement with those on the primary and Secondary ahafts. The gearwheel on-the driven shaft may be slid into engagement either with the third wheel of the layshaft, or by means of the clutch teeth, with the wheel eit.the primary shaft. It may also be left in an intermediate position. when it is in engagement with neither of these two wheels.. -The changespeed lever operates to slide this single wheel.

The operation of the box ions follows': When in first epeed, as in diagram (1), the sliding wheel is in engagement with its fellow nn the layshaft. The exterior clutch member is brought into engagement with the flywheel. The drive is then from the flywheel to outer clutch member, along • the secondary shaft, thence to the lavshaft, and back again to the wheel on he driven shaft. While the outer clutch is-..thus engaged, the driver's foot is kept upon the clutch pedal, which is thus held down. On lifting his foot the clutch metnber slides back, releasing the outer clutch and engaging the inner one. The drive then runs from engine flywheel to inner clutch, primary shaft. lay shaft. and back again

to driven shaft, as in diagram 2. To engage third speed, the change-speed lever is'moved in its quadrant, and the sliding wheel is engaged by -means of the clutch teeth with the wheel which is keyed to the primary shaft. This is the only occasion when the change-speed lever ia -used. The outer clutch is engaged by means of preSsure on the pedal. The drive is then transmitted from engine flywheel to outer clutch, via secondary

shaft to the layshaft, and back again to the wheel of the primary shaft through the claw clutch to the wheel of the driven shaft. To engage fourth speed, the clutch pedal is released, thereby disengaging outer frietion, clutch and engaging the inner one. The flywheel, inner 'clutch member, primary shaft, claw clutch, and wheel on driven shaft afford a direct drive on top.

In this description we have avoided any reference to reverse gear. To affect a reverse, a double pinion is mounted upon a spindle within the box. When the sliding wheel of the driven haft is in the usual position, the reverse can be caused to mesh wit-h it and the third wheel of the layshaft. The ratio of the reverse gear depends upon which clutch is engaged.

Detail Improvements.

NO. 145,991, by F. W. Apperley, deacsibes an electric jack, which may be operated by Current from the usual Car lighting sets.

A simple ratchet gear which may be applied to the clutch pedal of any ear. is the subject of patent No. 145,979 by F. C. Denham.

Henry Ford and Son describe in No. 129,996 the arrangement of the dashboard steering gear and clutch-Operating gear of the Fordaon tractor. .

No. 135,455, by Eta blissements H. C Nchat, describes a construction qf trailer drawbar, designed to ensure that the wheels of the trailer follow precisely the tracks made by the tractor.

No. 128,915 by the U.S. industrial Alcohol 'Co. gives the formula for the manufacture of a motor fuel containing alcohol, benzoic, and petrol, together with a preparation of sulpharic ether. The utilitY of the latter is, apparently, that it . prevents crystallization of the benzole• at temperatures which are met with at high altitudes.

.-A simple arrangement of gearing 'is described in No. 134,199 by M. Chassin. It is particularly applicable for use in connection with electric starting and lighting outfits of the single unit class in which, when• the unit-is operating as 'a motor, it must revolve at a high speed compared wit-h that of the engine; but when operating as a dynamo need not revolve so quickly. •


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