Patent GB-110228-A (GB)
Title: Improvements in Driving Mechanism for Valves and the like.
Inventor: DEAN PETER PAYNE
IPC: F16K31/05
Filed: 1916-11-16
Abstract: 110,228. Dean, P. P. Nov. 16, 1916. Electrically - actuated valves.-Relates to motoroperated actuating- mechanism or gearing for valves and the like, and consists in means for mechanically or electrically de-clutching the gearing, which is of the planetary or similar type, and simultaneously cutting-off the power supply (e.g. electric current) to the motor by automatic means operated from the driven shaft at the end of the valve &c. movement; the arrangement is such that the mechanical disconnection is only momentary, the gearing being immediately thereafter re-clutched whereby the unspent momentum of the motor is absorbed in jamming the valve, &c. The drive from the electric motor 4, for example, comprises a worm 5 on the motor shaft, a worm wheel 6 and attached pinion 23 on an intermediate hollow shaft, and planet pinions 25 carried on a rotary spider or yoke fixed on a concentric driven shaft 1<a>. The planet pinions 25 also gear with an internally toothed wheel 26 which, during driving, is held stationary by a double-sided pivoted catch pawl 30 engaging a projection 31 thereon. The driven-shaft 1<a> is geared to a traversing screw 39 so that, at the end of the valve &c. movement, a nut 40 thereon operates to reverse the pawl 30 and simultaneously opens one of the two limit switches 41, 42 to cut off the current. The reversal of the pawl 30 releases the wheel 26 which then makes an idle revolution, whilst the planet yoke and driven shaft 1<a> and the valve &c. become stationary; when the projection 31 strikes the opposite side of the pawl 30, the drive is restored to allow the unspent momentum of the motor to jam the valve, &c. When the motor is subsequently started in the reverse direction, the wheel 26 is free for almost a revolution, until the projection 31 strikes the pawl 30; this allows the motor to get up speed and start the drive with a hammer blow. The pawl can be brought to its mid-position by hand means to disconnect the motor and to enable the valve &c. to be operated by manual means. The limit device 40 operates the pawl 30 mechanically through spring-operated tumbler levers 45, 47; the limit switches 41, 42, one for each end of the valve movement, are operated therefrom also by projections 65, 66 operating between jaws 64. The switches are of the spring-tumbler type. The pawl 30 may be operated by an electro-magnet or solenoid by means of auxiliary contacts on the limit switches 41, 42. The pawl may then be replaced by a sliding-bolt catch. A lamp is connected between each limit switch and the electric main to indicate the position of the switches and the valve &c. Fig. 9 shows an arrangement in which the traversing-screw 39 and limiting-devices 40 are dispensed with. In this modification, the current is cut off at the contacts 125. 126 when the valve &c. reaches the jamming position, by an electromagnetically-operated catch bolt 121 which is responeive only to a predetermined overload in the motor circuit. The arrangement shows a reversing switch 152, electric mains L<2>, L<3>, and a control station 112 which includes a circuit breaker 132 held by an electro-magnet 131 in the closed position as shown, and circuit contacts 143, 144. On pressing in the knob 138 to start the motor, the circuit-breaker 132, 133 and the contacts 143, 144 are closed whereby the main circuit for the motor passes through the contacts 143, 144; the circuit of the solenoid 122 is thus placed in shunt from the main motor circuit whilst the motor is being started. The knob 138 is then released and the spring 145 opens the contacts 143, 144 which puts the solenoid 122 in the main motor circuit. The motor continues running until it is slowed down or obstructed bv arrival at the jamming of the valve &c. or otherwise, whereupon the overload current through the solenoid raises the bolt 121 which opens the contacts 125, 126 and the motor circuit. The magnet 131 then releases the lever 132 of the circuit-breaker which is withdrawn by the spring 136. This action puts the shunt circuit of the lamp 151 in the motor circuit and thus indicates the stoppage of the motor; the resistance of the lamp is sufficient to prevent the restarting of the motor. In the mean. time, the catch bolt 121 has dropped, and the inertia of the motor, if any, rotates the toothed wheel 117 until the projection 118 strikes the returned catch 121, whereby the unspent momenturn of the motor is absorbed in jamming the valve or other device.