The Automatic Adjustment of Brakes
Page 62
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A Resume' of Recently Published Patent Specifications
BRAKES which automatically. adjust themselves to take up wear are described in the patent (No. 338,503) of J. A. Furness, 6, Freelands Road, Bromley, Kent. The brake described is of the ordinary two-shoe pattern in which the shoes are hinged to a back plate and the opposite ends are separated by means of the equivalent of a cam.
The main feature of the invention lies in the abutments against which the shoes bear when in the off position. Two discs (A and B) are mounted eccentrically on the back plate,
the distance apart of the pins on which they are mounted being constant. Arms extending from the dises are drawn together by the spring shown, but owing to the major facia being on the side of.the arms, no rotation ofboth discs can take place in directions which would permit the arms to approach nearer to each other.
Rotation of the disc A can, however take place in the direction of the arrow, the other disc (B)• following it up, but A will resist rotary movement in a direction opposite to the arrow. In other words, the pair of discs forms a unidirectional drive, allowing a slight' amount of rotation in one direction, but jamming when forced in the opposite direction.
A link (C) is pivotally connected to the be and is provided with a slot through which passes a pin extending from disc A. The length of this slot determines the amount of clearance allowed between the shoe and its drum. As this slot is not clearly shown in the drawing in the specification we have made the enlarged view shown.
In operation the shoe moves towards its drum, and as wear takes place its movement in that direction gradually
increases. As this takes place disc A is slightly rotated in the direction of the arrow, but the return movement of the shoe is governed entirely by the length of the slot, as disc A can only be moved in one direction.
An apailication of the same principle is shown in which the pulI1•od is jointed to the hand or foot levers (D and E).
These levers are separate and are only connected, when acting in one direction, by the pair of eccentric discs shown. The relative positions of E and D automatically adjust themselves to wear in the manner already described.
A Duplex Universal Joint. pATENT No. 338,667, by Manning and Co., 208, South
La Salle Street, Chicago, U.S.A., relh.es to a universal joint which will transmit power through a greater angle than is possible with such joints of ordinary design. It should prove of use in vehicles where wheels are employed for the double purpose of driving and steering.
Besides being able to work at a greater angle, the joint has a centring device in the form of a ball and socket, and is claimed to have means for carrying more than the usual amount of lubricant.
Each shaft has an enlargement formed at its end and through this is a hole to receive a pin (A). Each of these pins carries a yoke (B), as shown in perspective, which is in the form of -a square frame with hollow bosses to receive the aforementioned pins (A) and other pins (C) formed integral with the frame on the other two sides. A member (Ill) in the form of a ring carries on each side two Mocks (E), which are secured to the ring by means of bolts. These blocks are bored to fit pins C.
The assembly of the joint is. as follows :—The yokes are secured to their axles by means of pins A, which are held in place by. taper pins passing through their centres. The ring member,is"then placed between the two shafts, and the ball and .socket engaged. The blocks (E) are then slid on pins C and are secured to the ring by the bolts which pass right through them and the ring, a pin being formed' on each block to engage with a hole in the ring and thus elieve the bolts of shear stress.
The ring D is described as being hollow, but no mention is made of bow this is to be accomplished. The hollow ring is said to hold a supply, of lubricant which can find its way to the various hearing surfaces through passages cut in the various parts.
A Place for Luggage and a Means for Ventilation.
IN specification No. 336,127, by. Charles 11. Roe (1923),
Ltd., of Leeds, C. Er. Roe, West Yorkshire Road Car Co., Ltd., and F. J. Chapple, an overhead luggage rack for coaches or buses which provides a means for ventilation and acts as a reflector for the lights is described. The channel Which is formed where the rack joins the wall of the body is provided with means whereby air can escape.