PATENTS SUMMARIZED.
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Aninteresting Alley and MacLellan Invention.
The latest suggested development in the design of the Sentinel steam wagon, as indicated by a recent patent specification No. 111,872—the inventor being Mr:S. E. Alley—is td incorporate the differential gear with the engine crankshaft. The designer's wish is, evidently, to eliminate, if possible, the gearbox, or at the very least, by placing the differential gear in this position, to reduce its weight to a, minimum consistent with the essential requirements for strength. This reduction is best effected when, as in'this ease, it is carried on the shaft-which revolves at the highest speed
of any in the transmission. •
As illustrated, and as it will probably be' used, the gear is applied to a twocylinder engine, upon which the cranks are set al right ankles. The cranks do not directly-drive the crankshaft, being carried on the ends of the shaft, on bushes, so that the two halves of the shaft are free to revolve inside the cranks. Each crankpin it hollow, and bushed, and through it, taking a bearing in the bush, is a shaft which carries a pinion at each end. The two inner pinions— those which come between the two cranks —gear one with another, thus coupling together the two shafts within the crank pins. -The outer pinions engage with otherS aCtually keyed to the crankshaft. The two cranks are fastened together by mean e of a substantial distance piece, which, incidentally, also serves as a balance weight. It will be gathered that the two cranks serve the same purpose as the differential case in an ordinary differential gear as it is commonly designed. The pinions carried by the shafts which run within the crank pins are the satellite pinions. Those gears which are keyed to the portions of the crankshaft are the sun wheels, and correspond ,precisely to the gears which are keyed to the two driving shafts of a live axle. It may be presumed that the gear wheeTs on the crankshaft could cominuniAte directly with
suitable gear rings on the road wheels of the vehicle, in Which case, provided that these two road wheels offered equal resistance to turning, the two portions of the crankshaft would revolve in time with one another and with the cranks. In the event of one of them, as in going round a corner, being constrained to run more slowly than the other, the• balariCe would be made up by a differential movement of the two portion% of the Crankshaft, in precisely the same manner as it occurs with an ordinary differential axle.
Tractor Springing.
Specification No. 111,941, by G. F. Joseph and W. H. Brown concerns a design of front axle which allows a transverse axle to.revolve in a. vertical plane about its centre as well as to rise and fall under the influence of its load. It is thus rendered better able to negotiate even ground. The. usual arrangement of spring and axle is inverted, the Ackermann-type axle being carried on shackles at the ends of a transverse semi-elliptic spring. The spring is attached to a bracket, pivoted on a pin disposed lengthwise of the chassis. The same bracket extends' upwards and serves as a guide to the axle and acts on the same principle asthe horn blocks on alonaMotive axle,' preventing -it from moving in any direction but the vertical. -The axle is maintained in a central position on the shackles of the .spring by stops which are formed on it, both in front and behind. These stopsbear against the edges of the pivoted bracket.
An Air Cleaner and Filter. .
It has been 'clearly demonstrated on more occasimOS than one that Some means of cleaning the inlet air to the carburetter is advantageous. • The provisionof some device for.attaining this end in the case ef the engine of an agricultural tractor is 'essential. F. C. Orem has devised a simple and effective fitting for the purpose which is described in patent No. -411,882. The body of the . filter' takes' the form of a shallow cylindrical dish, from the base of Which a pipe leads to the inlet oPening of the carburetter. A layer of felt clipped between. two skeletonie discs covers the open mouth of the cylindrical basin. It is held in Place by four wing nuts, and can therefore he quickly removed in case of need. The inventor does not confine himself to theuse of felt as a filtering medium,andpoints out that the area of this filter must be many times that of the inlet to the carburetter. Experiments; he states, have shown that about.40 times the area is the most suitable proportion.