Patent GB-343717-A (GB)
Title: Improvements in brake operating mechanism
IPC: B60T11/04
Filed: 1930-02-04
Abstract: 343,717. Transmitting-mechanism for brakes. CONSTANTINE, W. W., 111, Grosvenor Road, London. Feb. 4, 1930, No. 3709. Convention date, March 23, 1929. [Class 103 (i).] In a brake-operating mechanism for motor vehicles wherein the initial portion of the brakeapplying movement acts on the brake with a lesser mechanical advantage than the subsequent portion of such movement, the increased resistance encountered when the brake clearance has been taken up causes the displacement of an axially sliding clutch sleeve from yielding brake-applying engagement with a coaxial member acting with the lesser mechanical advantage into firm brake-applying engagement with a coaxial member acting with greater mechanical advantage. Figs. 2, 3 show one form in which a pedal 19 is connected by rods 23, 25 to arms 39, 46 on hubs 41, 47 rotatable on a shaft 27 actuating the brakes through rods 31, the connection with the arm 39 being through a spring 69. On operating the pedal 19 both arms 39, 46 move, the long arm 46 turning freely on the shaft 27 while the short arm 39 by means of a projection 43 engages the dog-clutch sleeve 53 keyed to the shaft 27. When clearance has been taken up rotation of the shaft 27 is prevented by the rods 31 and the sleeve 53 is forced axially against a spring 51 by the projection 43 riding along its face, and engages the teeth of the hub 47 of the long arm 46 through which the brakes are applied. Fig. 7 shows a modification in which the dog-clutch sleeve 109 is freely rotatable on the shaft 17 and is directly operated by an arm 123 constituting the pedal, which first rotates a long lever 105 to take up clearance and then is moved axially by the projection 115 so that the teeth 111, 113 engage, further movement of the pedal operating the arm 107 to apply the brakes. In a second modification, the hub of the long lever 46<1> Fig. 8 has a tapered recess 150 to receive a tapered extension 143 of the clutch sleeve, a series of rollers 145 separating the two tapered parts. A spring 51 bearing on a fixed collar 52 is used to thrust the sleeve 53<1> axially and a spring 54, interposed between the hub of the lever 46<1> and a fixed collar 37 permits a slight axial movement of the lever 46<1> to prevent seizing of the rollers. The operation of this form is similar to that shown in Fig. 3. The Specification as open to inspection under Sect. 91 (3) (a) comprises also a further modification shown in Fig. 4 (Cancelled) in which a pedal 75, mounted on the shaft 17, carries a pawl 79. A depression 85 in the curved surface 83 of the pawl is held normally by a spring 93 against a pin 87, on a lever arm 89 connected to one end of a rod 102 for operating the brakes. A short lever 95 with ratchet teeth 97 mounted on the shaft 17 is also connected by a rod 103 with the brakes. In operation, movement of the pedal 75 first rocks the lever 89, by means of the depression 85 in the pawl, until clearance is taken up. The pawl then moves relatively to the lever 89 and its curved surface causes it to pivot about the pin 81 and engage the teeth 97, the brakes being then applied through the rod 103. This subject-matter does not appear in the Specification as accepted.