Patent GB-181842-A (GB)
Title: Improved means for preventing injury to resilient tyres of road vehicles by loose sharp objects on the road
IPC: B60S1/68
Filed: 1921-03-23
Abstract: 181,842. Ferranti, S. Z. de. March 23, 1921. Wheel scrapers.-A device for removing nails, flints, &c. from pneumatic tyres comprises a holder located within the wheel periphery and fixed to a part having no movement relatively to the wheel axis, and a catcher-blade yieldingly supported by the holder in proximity to the tyre tread so that it removes nails to be picked up by the tyre but can be displaced by excessive impact away from the tread along a path whose centres of curvature are on the same side thereof as the wheel centre. As shown in Fig. 1, the holder H is secured to the brake casing at 21, 22 and carries a detachable socket piece K to which is pivoted an arm A carrying the catcher-blade B. The arm A is carried by a box-lilce member C which is pivoted to the socket piece K about an axis X and contains a spring tending to hold the blade B against the tyre, this position being determined by stops 34 with an interposed buffer 35. The outward swing of the arm A is limited by stops 37. The, socket piece is adjustable, radially of the wheel, on the holder H, and may also be rotated thereon so as to bring the blade into a position in which it best conforms to the tyre tread. The holder may be made integral with the casting which carries the brake shoes. As applied to a steering wheel, the holder mav be integral with the steering arm of the stubaxle, or it may be secured to the stub-axle casting as shown for example in Fig. 3. The holder H is formed with an integral forging H<1> bent at 23, 24 for attachment to the, stub-axle casting by the nut 27 which also secures the steering arm. A clip 28 secures the holder to the upper end of the axle casting. One form of yielding joint between the swivel arm A and socket piece K is shown in Fig. 19, the arm A and holder H being tubular, although in a modification they are of channel section. The box C containing the spring S has an arm 33 for carrying the arm A and a pivot 36 for engagement with a hollow stud 38 integral with the socket piece K which is split and clamped to the holder by the screw L, Figs. 1 and 3. The spring S may be dispensed with by forming the engaging surfaces of the joint between the swivel arm and socket piece with serrations held in engagement by a bolt and spring washer. The joint may also be made with considerable frictional resistance. In the modification shown in Fig. 25, a stiff spiral spring 42 arranged between the spring-box C and socket piece K serves to deaden shock at both extreme positions of the swivel arm A. One end 43 of the spring is screwed into a trunnion block 44 on the box C, and the other end 45 is squared and slides in a lug 46 on the socket piece K, stops 47 limiting the movement. When the swivel arm is moved away from the tyre, the rounded part of the spring-end 45 enters the lug 46 so that the spring-end 43 may be turned in the block 44 for adjustment. As applied to a cycle, the swivel arm is U-shaped to embrace the tyre, both its ends being carried by socket pieces attached to holders secured to the frame or forks on each side of the wheel, or the frame or forks may serve as holders. A simple form applicable to the rear wheel of a motor-bicycle is shown in Fig. 12. The U-shaped arm A is secured at its ends to springs 58 carried by studs 59 on the holders H which are notched at 60 to engage pins 61 on the arm A. The swivel arm may comprise a spring blade secured direct to the holder. The catcher-blade B may be detachably secured to the swivel arm A as shown in Fig. 29 or 30. The end of the arm A is of triangular section, and the blade B has welded thereto plates B<1>, the blade being secured to the arm A by bending over parts B<2>, Fig. 29, or by hammering down pips p, Fig. 30, into recesses in the arm.