A CATERPILLAR MOTOR LORRY.
Page 28
If you've noticed an error in this article please click here to report it so we can fix it.
A Resume of Recently Published Patents.
It is difficult te. imagine, in a welldeveloped Country; plentifulay supplied with comparatively good reads, as is this England. Of ouis, that any use •could be found •fot a -motor lorry which ,runs. on caterpillar tracks. Nor is it likely, we think, that circumstances will ever arise, at least in time of peace; Which wilil call for a vehieleiso provided. It is easy to understand, however,' that there might very well be quite a considerable demand for a caterpillar • truck in the Colonies, andesabroad in . such places as South Ameriea,. and also in the ice. and snowbound regions, : . wherein a caterpillar would be yell ableqo proceed, probably even-bitter thana sledge. A certain amount of, interest attaches, on that, account, to pateet.. specification No. 139,700, for which Caterpillararactors, Ltd., are responsible. It describesouch a truck,' or rather a. cantrivance, which may be applied to any live axle chassis whereby it is convertible from a wheeled vehicle to a caterpillar-driven truck. The axle of the wheeled vehicle remains in situ; as also the springs, although it would seem that, if eaoh of the latter is not shackled at botts.encls it would be better to alter it ED that. it bec-omes,so. In place-of the wheebhubs, twO brackets are fitted, so as to .bear on the ends of 'the existing. axle. They are aorizontally.disnosed'in the main, with the bulk of 'them behind', the axle, and forked' to receive the rear and driving sprockets of the chain ,tracks. Near the front ,of each of the •htackets a• vertical 'pivot is. carried, and these -serve as the rear attachments for a pair • of radius rods; . which while allowing the bracket,: to rise:andfall under' the influence of the springs, neveritheleis restrain them from any movement sideways, or from swinging round 'their bearings on the .asclecase. _ The driving dogs -on the ends of the live axle.dtiving shafts are removed,, and their places taken by oidinary chain sprockets. 'Other' sprockets, similar to these, are secured to the, driving sjorockets of the caterpillar tracks', itnd the two pairs of chain sprockets,-together with the -thainsrcote: stituteosthe means of 'find drive.
c58' To the front lower portion of each of the main brackets is hinged a second, which •serve4 asa. support for the front trailing . wheel fees the caterpillar track. This bracket is aleo supported on three flanged raiders which run on the inside of the track. The idler wheel of the track is rubber tyred, the object of this unusual construction being that of rediking the.noise which is regarded as an inseparableibfeature of the caterpillar. The tracks are built up ,of shoes which are smaller than those which are customarily tused, and it is"claimedthat the construction generally is suitable for speeds of from 15 to 20 miles an hour.
The hinged joint between' the Main brackets and the forward trucks, which are supported on the inside of the tracks, is ofivalne or two reasons: It allows of thetflauged rollersfolloWing the motion and flexing of . the track, so' that the weight is evenly spread over a geed number of thelinks. It also allows the distance between the two track wheels to be shortened or lengthened to some extent in -order to allow the track. to accommodate' itself to the unevenness of .tie road surface, without either undue tension or undesirable slackness of the track.
Detail Improvements.
A peculiar type' of differential gear is -described in specification No. 139,607,. the patentee being John Krohn. A plate carried in the middle of the usual differ, ential case is pierced for four small discs, which are equally spaced 'round the. central hole inwhich the main .driving. axle bearings are supported. Each Of the four discs carries a pin which is not in the centre of the disc. , To the pins are secured two gears, that on one side of ' the main disc is an eternal gear, and • engages with an internal gear on -one driving axle ; that on the other side of the main disc is an internal gear, and itis in engagement with an externally toothed wheel on the other driving shaft. In ordinary circumstances the whole gear • revolves en bloc, driving the two axle shafts atequal, Any difference in the resistance offered by de two road -wheels causes relative motion sbetween • the pair of wheels which are carried by the eccentric pins and the main disc,-which motion involves -the smallerdisc in movement in the large disc. This. movement is frictionally resisted, but ' only to a noticeable extent. when therelative Motion is fairly considerable.
It is claimed that .whert the movement _called for is no more than that which' is required of a gear when the _ vehicle is turning a corner, the differential offers. practically -no resistance, but. that in the event of one wheel losing grip it refuses to act,but transmits the power to the wheel, which is in good tractive contact with the ground.
. A novel arrangement. of ,friction drive . is described in-'specification No. 139,90, by T. S.Smith. It is illustrated with reference to a single-cylinclered 'engine, the crankshaft of whieh is divided so that two connecting reds are needed, one to each half of shaft. At the ends of . the latter are two flywheels, ' which are drawn towards one another by springs. Bearing on the inner faces • of the flywheels is a single driven. disc. The two halves of the crankshaft revolve in contrary directions one to the other.
The feature orthe splash-guard, which is patented by G. C. Whittle and another, in No. 139,674, is its adjustabilityto suit various wheel diameters.
A safety lockingdevice for electric vehicles, whereby any possibility of the machine being started while it is "on charge," or of its being put " charge" while the starting lever is in' tbe operative position, is obviated. The , patentee is H. Crochat, and the specification is numbered 139,710.
A. C. Pictet in No. 139,424, bypasses a -small portion of the exhaust gases, so that it escapes in, view of the driver, thus enabling him to see if it is clear or smoky without there being any necessity for Rim to turn round to look. .
A strut or stay for stiffening the front' forked radius rod of a Ford car is the subject of specification No. 139,729, by
C. H. Helsley. .