Patent GB-756078-A (GB)
Title: Improvements in endless tracks for vehicles
Inventor: BONMARTINI GIOVANNI
IPC: B62D55/08
Filed: 1954-01-21
Abstract: 756,078. Endless tracks for vehicles. EST. ETABLISSEMENT SCIENCES TECHNIQUES. Jan. 21, 1954 [Jan. 22, 1953], No. 1813/54. Class 79 (1). In an endless track for vehicles, links are provided each having a roller freely rotatable about an axis parallel to the length of the track and a device is provided for preventing rotation of the roller. As shown in Fig. 1, the endless track 4 passes round an idler 2 and a driving sprocket 3 mounted on a frame 1 secured to the vehicle, each link 4<SP>1</SP> of the track carrying a bracket 6 mounting a pair of rollers 5, 5<SP>1</SP>. Carried by a shaft 8 on the frame 1, Fig. 2, are discs 7, 71 having flanges 9 shaped to engage the rollers 5 to prevent rotation thereof, thus preventing lateral movement of the vehicle. Additional discs may be provided at 7<SP>11</SP>, Fig. 1. In a modification, Fig. 3, the frame 1 carries a shaft 14 on which are mounted flanged rollers 13 and a sleeve 15 having on its eccentric surface a roller 17.. By means of a lever 16 the sleeve can be rotated so that the roller 17 engages a single roller 5 carried by each link 4<SP>1</SP>. Such engagement transfers the weight of the frame 1 directly to the roller 5, the link 4<SP>1</SP> still being guided by the flanges 18 on the rollers 13 and the engage - ment preventing rotation of the roller 5. Other similar modifications are shown in Figs. 4 and 5 (not shown); in Fig. 4 the sleeve 15 is extended to carry the rollers 13 eccentrically and the roller 17 concentrically, and in Fig. 5 the shaft 14 and sleeve 15 are replaced by a cranked shaft which has opposite throws for the rollers 13 and roller 17. In another modification, Fig. 6, the rollers 5 of each link are prevented from rotation about their axes 11 by engagement between adjacent peripheries of the rollers, each link being formed of parts 4<SP>11</SP>, 4<SP>111</SP> articulated about an axis 27. The frame 1 carries a shaft 14 controlled by a lever 21 and having eccentric portions 23 carrying rollers 13 and a concentric portion 22 carrying a roller 24. In another modification, Fig. 8, the roller 5 of each link 41 can be positively braked to prevent rotation about its axis 11, the roller carrying a drum 33 engaged by shoes 32 carried on levers 31 pivoted to the link. The levers 31 are actuated by rollers 30 eccentrically carried on a shaft 14 controlled by a lever 21 and carrying a roller 29 which transfers weight from the frame 1 to the link. The roller 5 may alternatively be hollow and provided with expanding brake shoes which are mechanically or hydraulically controlled by a shaft projecting from the link to engage one roller 30. In further modifications shown in Figs. 10 and 11 the rollers can be retracted from the ground and non-rotatable members brought into engagement therewith to prevent lateral movement of the vehicle. In Fig. 10 the roller 5 of each link is mounted in a frame 36 pivoted at 35 to the link 4<SP>1</SP>, the frame 36 having extensions 39, 41 engageable with rollers 38, 40 carried by the frame 1 so that the roller 5 and a part 37 of the frame 36 can alternatively be brought into engagement with the ground. In Fig. 11 the rollers 5 of each link 41 are carried by frames 42, 42<SP>1</SP> pivoted together at 141 and having at their upper parts a spring 43 so that normally the rollers 5 are in engagement with the ground. Projections on the frames 42, 42<SP>1</SP> are engaged by rollers 13 eccentrically mounted on a shaft 14 which also carries a roller 24 engaging the link 4<SP>1</SP>. By rotation of a lever 21 on the shaft 14 shoes 37, 37<SP>1</SP> on the frames 42, 42<SP>1</SP> can be brought into engagement with the ground instead of the rollers 5. Any number of the devices shown in Figs. 3 to 8 may be provided for the lower run of the track, for example as in Fig. 9 (not shown). Each link of the track may be provided with a rubber pad for engagement with the idler sprocket, Fig. 12 (not shown), or the idler sprocket may be provided with a rubber tread for engagement with the links, Fig. 13 (not shown). The lower run of the track between the idler sprocket and the ground engaging portion may have its radius of curvature gradually varied by a suitable set of rollers, Fig. 14 (not shown). In the embodiment shown in Figs. 15, 18, 19 and 20 the endless track 49 passes around an idler wheel 50 and a driving sprocket 51, and is formed of articulated pairs of links 59, each pair of links carrying a plate 62 having ribs 63. Rotatably mounted by shafts 64, 65 of the ribs 63 of each plate 62 are a pair of ground engaging rollers 57, 58. Arranged above the ground engaging run of the track 49 is an arm 48<SP>1</SP> carrying sets of rollers 52 ... 55 round which are trained two auxiliary endless tracks 56. Each track is formed of rubber shoes 66 with lateral plates 72 and bushings 70, 71. The bushings 70, 71 receive bolts 73 each carrying a pair of links 74 for connecting adjacent shoes 66. Each shoe 66 presents to the lower run of the track 49 a face 67 having a curvature corresponding to the rollers 57, 58. Each set of rollers 52, 55 comprises a shaft 80 carrying a pair of flanged rollers 81 and the pair of rollers 52 or 55, the rollers 81 and rollers 52 or 55 having opposite eccentricities. The flanges 82 on the rollers 81 guide the links 59 of the track 49 and the flanges 86 on the rollers 52 or 55 guide the auxiliary tracks 56. In the position shown in Fig. 20 the rollers 81 bear on the links 59 and the faces 67 of the auxiliary tracks 56 do not bear on the rollers 58, leaving the latter to rotate about their axes. By means of a lever 90 the shaft 84 can be rotated so that the rollers 81 do not bear on the links 59 but the faces 67 co-operate with the rollers 58 to prevent their rotation and hence lateral movement of the vehicle. The lifting or lowering of the end sets of rollers 52, 55 increases or reduces the braked zone of the rollers 58.