| 摘要 |
1,065,682. Tyre pressure indicating devices. O. NECKER. April 8, 1964 [April 9, 1963], No. 14589/64. Heading B7C. [Also in Division H2] A device for indicating pneumatic tyre pressures comprises a switch mounted in a vehicle wheel and having a diaphragm exposed to the internal tyre pressure and a leaf spring which bears on the diaphragm and on a fixed abutment adjustably secured in the switch housing so that displacement of the diaphragm causes the leaf spring to act on a series of electrical contacts, the switching position of that portion of the leaf spring which acts on the contacts being dependent on the position of the diaphragm and independent of the centrifugal force due to rotation of the wheel, the device further comprising electrical connecting means including a commutator and means for indicating the tyre pressure as the switch contacts are operated. The switch is incorporated into an electric circuit (Fig. 1, not shown) in which the leaf spring is represented by contact arm (20) and the switch contacts by numerals (21), (22), (23), the switch housing being indicated by the broken line (11). The circuit includes resistors (24), (25) connected to a slip ring (14), (15) so that as the arm (20) moves from right to left of Fig. 1 with increase in tyre pressure loss the signal given by a lamp (17) mounted on the dashboard of the vehicle changes from a dim to a bright light and then to a flashing light. In the embodiment of the switch shown in Fig. 10 the leaf spring 20b is substantially U-shaped and its lower limb 44 is supported on a screw 50a which is axially adjustable to vary the initial stress of the spring. The contact arm (21) is formed by a pin 21a which may be a permanent magnet to damp natural vibration of the spring 20b. The free end of the upper limb 43 of the leaf spring carries a contact element 47 which overlies the pin 21a and co-operates with contact springs 22a, 23a spaced above the element 47. With increase in pressure loss the limb 43 of the spring 20b moves so that the contact element 47 engages the spring 22a, and with further loss causes the spring 22a to contact the spring 23a, thus setting up the required circuits shown in Fig. 1. In a modification the initial stress of the leaf spring is varied by a central pin which is secured against axial displacement and carries an eccentric stud for engagement with a slot in the lower limb of the leaf spring. In a further embodiment (Fig. 3, not shown) the leaf spring is a buckling spring (20) arranged radially with respect to the wheel, the switching movement of the electrical contacts being effected substantially at right angles to the spring on movement thereof with change in tyre pressure. |
