Patent GB-191413449-A (GB)
Title: Improvements in Pneumatic Clocks.
Inventor: HAHL AUGUSTUS LOUIS
IPC: G04B1/26
Filed: 1914-06-02
Granted: 1915-06-02
Abstract: 13,449. Hahl, A. L. June 2. Pneumatic clocks.-Alternating pulses of compression and expansion are sent to distant indicators or secondary clocks through pipes filled with air at atmospheric pressure by an oscillating beam machine acting on a bellows for each system of pipes, such machine being driven by a spring-motor which is released intermittently by a time-train coupled through a maintaining-spring. The machine is designed to relieve the motor of resistance at starting, to increase the leverage as the compressive stroke proceeds (thereby if desired dispensing with the relieving-device), to open valves for giving atmospheric communication by the motor independently of the time-train, to render leakage harmless, to adjust the stroke, to connect the motor and the time-train by direct detenting- mechanism, and to provide, for indicators which are driven by their own motors, controlling- mechanism comprising alternately-acting detents. The operation of the bellows 100 of the conduit 102 is derived from a rocking tooth sector 113 through a T-lever 109 and a lever 104 of the second order on a knife-edge 106, the two levers having a pin-and-slot connexion, the pin 111 of which is carried by a slide 130 on the arms of the T-lever. Two arms 116, 117 combined with the sector are connected by straps to two similar arms 118, 119 on independent co-axial pivots 122 eccentric to the shaft 120 of a disk 127 bearing three pins 128 each side, halving angles. The wheel being turned intermittently by the motor through 60 degrees at a time, a pin operates the lever 118 or 119 by wiping an attached tappet 126 or 125, Figs. 25 and 26. The momentum carries a leg 228 projecting from the T-lever beyond a detent 229 or 235, so that the motor is not under load till one of the teeth 233 on the disk has tripped the detent. To keep the pressure in rest the same as the atmospheric, at the end of the expanding stroke of the bellows, a cap-valve 192 is lifted from the top of a branch pipe 185, by a lever 203 pivoted at 207 and operated by a pin-bearing disk 206. In case of leakage, this opening occurs earlier, because the valve lever 203 carries a swivel arm 209 with terminal pallet which is slued under the valve lever to thicken it, by a bell-crank 215, which follows the movement of a collapsible chamber 220 on the branch pipe. The shaft 120 of the pindisk 127 is geared with the terminal shaft 158 of the motor by bevels on a vertical shaft 154" which rises to the time-train. The connecting-rod 104<a> between the lever 104 and the bellows may have a spring section to allow the motor to complete its stroke in case resistance is increased by leakage. A secondary clock, Figs. 8 and 9, comprises a suitably driven great wheel 81 with two cams 74, 75 on its arbor, a pinion 82 with a long arm 83 on its arbor, and two detent levers 63, 64 bearing pivoted pallets 55, 56. A lever 54 on an arbor 60 between the bellows 53 and the pallets supports the pallets by a pin 59 passing through slots therein. As shown, the pallet 55 is obstructing the long arm, the other pallet being clear both vertically and horizontally ; but when the bellows shuts up, both pallets are slightly raised, and the arm revolves till the great wheel has made half a revolution. During this action, a bell-crank lever 67 subject to a spring 85 is operated by the cam 74 to shift the detent lever 63 back and therewith the pallet 55. At the conclusion of the action, the cam 75 lets a fellow bell-crank 68, pulled by a spring 86, shift the lever 64 to put the pallet 56 in the path of the long arm. When the bellows opens, the pallets are lowered and a similar cycle ensues. Driving-mechanism, mainspring.-Consists of a spring motor, Figs. 1, 6 and 7, a time-train with balance, Figs. 28, 29 and 31, and intermediate mechanism by which the time-train releases the motor intermittently and the motor winds up a spring driving the time-train. In the motor, comprising two mainsprings 13, each attached to a bridge 184, the main arbor 170 and the first arbor 163<a> of the train are provided with fast coned pulleys 165, 169 connected by a cord 165<a>, and the first wheel 163 of the train is loose on the arbor and is driven by a fast ratchet-wheel 166 and pawl 167. Winding-up is effected by a key on the first arbor. The attachment of the spring to the bridge consists of a pin 172, Fig. 7, sliding in a radial slot, and pivoted blocks 174 are provided on this bridge and on arms 178, 179 to keep the coils closed up except for cleaning. The first wheel 163 and its fellow 164 mesh with a central pinion 162, whence a conveying vertical shaft 154<a> is driven through a wheel 160, pinion 159, and bevels. The time-train 308 has its first arbor 305 co-axial with the vertical shaft 154<a>, and a lateral train from the shaft end in a long arm 301 to be released for a number of revolutions by the action of the timetrain. The spring 309, which drives the time-train, is attached to its first wheel 306 and to the shaft 154<a> so as to be rewound by this shaft. The slower arbor 319 of the side train carries three cams 327, 331, 328, the third being really only a bevelled finger projecting from the second. A counterbalanced lever 323 on an horizontal arbor 324 carries a V-detent 302, 332 in the plane of the second cam 331, and the arbor has two arms 325, 326 projecting to the top and bottom cams respectively. Normally the long arm 301 with buffer spring 302<f> is locked by a lug 300 on the short arm 302 of the V-detent, but as this arm has a notched end engaging with a pin-wheel 303 driven by the time-train, the long arm 301 is presently released. Then, during one revolution of the cams, and say ten of the long arm, the V-detent is drawn down clear of the pin-wheel, is given its initial position, and is raised again into engagement and locking position.