Patent GB-624921-A (GB)
Title: Improvements relating to endless tracks for vehicles and the like, and for conveyors
IPC: B62D55/24
Filed: 1947-06-17
Abstract: 624,921. Skates. SINGER, O. June 17, 1947, No. 15987. [Class 132 (i)] [Also in Groups XXX and XXXI] An endless track for a skate comprises a con-  tinuous flexible envelope of rubber or the like forming a sealed enclosure which is freely slidable on an internal guide frame shaped to the required track profile and carried on a suitable supporting structure. The supporting structure consists of a bar 10, Fig. 1, carrying shafts 11, on which are mounted grooved wheels 12. The flanges 13, Fig. 2, of the wheels support the track element 14 which is an endless belt of vulcanised rubber having an internal rectangular cavity. The guide frame consists of a looped steel core 15 arranged within the cavity and passing round the wheels 12 in arcs concentric therewith, the arcs being joined by straight or shaped sections as desired. Strip metal linings 16 and 17 preferably of bronze are bonded to the track element 14 during vulcanisation of the latter and lubricant is injected via two nipples 19 diametrically opposite on the inner side of the track member. The lubricant may be later washed out of one nipple by cleaning fluid injected into the other. The track may be formed with a tread 18. For heavy use an outer and an inner row of rollers 20, Fig. 4, are provided which bear respectively on the bronze strips 16 and 17 and are retained by spigots 28 in the channels 22-25 provided in an I-shaped core 21, the spigots being attached to caps 27 inserted in the ends of the rollers which are hollow for lightness. In a further embodiment, Figs. 5 and 6, the supporting structure, intended to have an area of contact with the ground equivalent to that of a wheel having an essentially larger perimeter, comprises a non- rotatable shaft 30 to which a pair of plates 31 is secured by welding; the plates being spaced apart and carrying welded drum sections 32 formed with channels 34 to retain the ends of rollers 35 arranged round their periphery, the plates and drum sections being elongated to provide surfaces of shallow curvature joined continuously by end portions of more acute curvature. A flexible metal strip 36 envelopes rollers 35 and forms a bearing base for the track element 37 which is bonded to it and located against the rollers by means of the channels 34 which act as shoulders engaging grooves 38 in the track element. Sheets of rubber 41 are united centrally with sealing glands 39 arranged on each end of shaft 30 and peripherily with the track, thus forming a complete seal for the relatively moving parts. In view of the pronounced variation in radius sheets 41 are arranged to be arcuately crimped on the minor axis of the track by forming a series of arcuate ribs 43 on plates 31 which diminish progressively between the minor and major axes. Diametrically opposite nipples 44 are provided for lubrication and cleaning. In manufacture, resist is used on all parts to which the rubber is not required to be bonded and the cavity between plates 31 is loaded under fluid pressure during the moulding process to avoid distortion.