GB455861A - Improvements in and relating to apparatus for indicating rate of acceleration and retardation - Google Patents

Abstract

455,861. Electric signalling systems. NEW, C. E., 20, Bucklersbury, Wallbrook, and ROSE, S. A. M., 111, Gray's Inn Road, both in London. April 26, 1935, No. 12579. [Class 40 (i)] Apparatus for the direct indication of the rate of change, acceleration or retardation in the physical variables pressure, speed and temperature comprises a moving member actuated directly or indirectly by the physical variable which operates an electrical generator the current from which is measured by an electrical instrument to show the rate of change of the variable and whether it is rising or falling. Fig. 1 shows the invention applied to the measurement of rate of change of pressure. The pressure acts on a piston 1 adapted to move against the influence of springs 3. The piston rod 5 is connected through a multiplying gear 6, 6, 6 on the last shaft of which is mounted an armature 7 rotating in a magnetic field 8 and supplying current to a moving coil instrument 9. When the pressure is steady the instrument reads zero, but when the piston is moving the instrument reads to one side or the other of zero according as to whether the pressure is rising or falling. In a modification, the rod 5 is connected to the core of a solenoid connected in circuit with the indicating instrument. In a second modification, the final spindle of the gear 6, 6, 6 rotates a magnet near a copper disc carrying a pointer and adapted to rotate about the axis of the final shaft against the influence of a hair spring which maintains the pointer at zero when the variable is steady. In a further form adapted to measure variations of speed, the needle of the speedometer has mounted upon its spindle an armature rotating in a magnetic field and connected to an electrical instrument indicating acceleration or retardation. Visible or audible signals as shown in Fig. 6 may be combined with the above devices. A disc 34 driven by the gear 6, 6, 6 has on its circumference cams 36 which actuate an impulse current transmitter 37. A friction change-over switch 38 is mounted on the spindle 35 and is adapted to rock between two contacts 39, 40 thus closing circuit 41 or 42 and causing lamps 43 and 44 of different colour to light up or gongs 45, 46 of different tone to be sounded. A light sensitive cell 47 may be substituted for the impulse transmitter 37, one or more apertures 48 being provided in the disc to come between a lamp and the cell. The impulses originated by the movement of the disc 34 may be used to energize solenoids and through ratchet gear to move a valve controlling for instance the fuel supply to a boiler.