Patent GB-330004-A (GB)
Title: Improvements in or relating to hydraulic brakes for aeroplanes
IPC: B64C25/48
Filed: 1929-03-05
Abstract: 330,004. Boughton, E. B., Emmott, W., Brock, D. T., (trading as Automotive Products Co.), and Burdon, A. C. March 5, 1929. Wheel brakes, applications of. -- An hydraulic braking system for aeroplanes of the kind described in Specification 296,798 comprises two separate systems a, b, each system being connected to the brakes of the landing wheel or wheels at one side of the centre line of the machine and consisting of a master piston and cylinder a<1>, b<1>, by which all play in the system is initially taken up and by which the degree of braking may be adjusted, a pressure-producing piston and cylinder a<4>, b<4>, arranged to be operated by the tail skid to produce a braking pressure proportional to the weight supported by the skid, and an auxiliary pressure adjusting piston and cylinder a<7>, b<7>. 7. Auxiliary pressureadjusting pistons of the two systems are interconnected by a compensating lever through which they may be operated to increase the pressure in one system and to permit a reduction of pressure in the other. According to one form two tail skids are provided each having fixed portions k, Fig. 1, and resiliently mounted portions e<2>. A cam e<3>, Fig. 5, is mounted on the member e<2 >and is adapted on upward movement to cause radial movement of a piston a<8> working in a cylinder a<4> secured to the fixed member k. The open end of this cylinder communicates by pipe lines with the master cylinder a<1>, b<1>. The pressure created by the piston a<8> is limited by spring-controlled pistons a<16>. The master cylinders and pistons a<1>, b<1>, are constructed in accordance with Specification 280,502, [Class 103 (i), Brakes &c.], and are operated through a compensating lever c and links a<3>, b<3> by a hand lever d mounted in a quadrant d<1>. This lever d and a second lever d<2> connected to the lever c, as shown in Fig. 1, are both provided with catches engaging in teeth provided on the quadrant d<1>; the catch which locks the lever d<2> in position is adapted to be released by the, mechanism releasing that of the main lever d so that, when the latter is operated to take up slack in the system, the lever d<2> is released and allows free movement to the compensating-lever c; when the operation is completed both the levers d and d<2> are locked to the quadrant. The master cylinders a<1>, b<1> are mounted at the highest point of the system and are connected to braking cylinders a<5>, b<5> by rising pipe lines a, b having flexible connections or lengths of flexible pipe where required. The pressure-adjusting cylinders a', b', are arranged either in front or behind the rudder bar h. They contain pistons a<6>, b<6>, Fig. 4, which are normally retained at the closed end of the cylinders by means of a spring loaded rod i<1> pivoted to a compensating bar i having slots i' at each end for engagement with pins a<29>, b<29> provided on the piston rods. When the hand lever d is moved to take up play in the system the pistons a<6>, b<6>, are forced into the position shown in Fig. 4, in which cupped ends a<37>, b<37> of their respective piston rods are in engagement with spring loaded push rods h<7>, h<8>, carried by a lever h<3> fixed to an extension h<4> of the rudder bar pivot, whereupon the rudder bar h is effective to vary the relative positions of the pistons a<6>, b<6>, for steering. The pressure exerted by means of the rudder bar h is limited by the action of the springs h<5>, h<6> since the push rods h<7>, h<8> are slidably mounted in sleeves h<13>, h<14>. Alternatively one tail skid only is employed operating two independent pressureproducing devices. The invention may also be applied to aeroplanes having more than two symmetrically disposed wheels.