Patent GB-494250-A (GB)
Title: Improvements in and relating to transmission mechanism
IPC: B63H21/22
Filed: 1937-04-23
Abstract: 494,250. Fluid-pressure servomotorcontrol systems; controlling reversing- gear; pressure-regulating valves; electric switches. BARKER, G. G. (Bendix Aviation Corporation) April 23, 1937, No. 11676. [Class 135] [Also in Groups XXIV and XXXVII] A remotely controlled power means for controlling the transmission or so-called reverse gear of marine craft comprises a pressure differential operated power device controlled by power operated valves and is associated with a power operated brake on the propeller shaft. In the arrangement shown in Fig. 3, the conrol lever 24 for the gear is operated by vacuum derived from the engine manifold acting on a double-acting piston 40 under the control of solenoid-actuated shuttle-lift auxiliary valves 50, 52. A second single-acting piston 294 is adapted to apply a brake 34 to the propeller shaft under the control of a solenoid-actuated auxiliary valve 304. The solenoids are included in an electrical circuit which includes ignition and cutout switches 106, 108 engine starter switch 110, manually operated selector switch 28 limit switch 322 and brake control switch 310 actuated by gear control lever and a two-way switch actuated by the piston of the main power device. With the engine started, to engage the transmission to give a forward drive the selector switch is moved to bridge the contacts 100, 94 energizing the magnet 50. This lifts a control valve to disconnect the left-hand end of the cylinder from atmosphere and couple it to the engine manifold. This causes the piston to move towards the left and move the gear control into the ahead position. In this position the lever opens a limit switch 322 to break the solenoid circuit and the piston itself moves a spring - loaded lever 142 to permit a spring-loaded contact to move into engagement with a fixed contact 118 and so connect the solenoid 52 to the neutral contact on the selector switch. Thus when the selector switch is moved back to neutral the solenoid 52 is energized admitting vacuum to the right-hand end of the cylinder and restoring the gear to neutral. When both gear control lever and selector switches are in neutral switches 310 and 114 are closed and the electromagnet 304 is energized to connect the cylinder 300 to vacuum and apply the brake. No limit switch corresponding to the switch 322 is provided for the reverse gear a spring 324 being relied upon to return the selector switch to neutral as soon as the hand is removed. In a modification, Fig. 4 (not shown), a single power cylinder operates both transmission gear and propeller shaft brake. In a further modification a vacuum regulating valve 336, Fig. 5, in the vacuum conduit is brought into operation by a solenoid 342 controlled by auxiliary contacts on the selector switch so that reduced suction may be applied to the main power device when it is desired to permit the slipping of the transmission during manoeuvring. The regulating valve comprises a spring loaded diaphragm adapted to co-operate with ribs 354 extending completely across a casing 332. In the switch construction shown in Fig. 12 the ignition and starter switches are combined in one switch mechanism 112 which is housed in the side of the selector switch casing 148. This casing which is adapted to be clamped at one end to the steering column houses at the other a rotary spindle 154 carrying an operating handle 152 held against the end of the casing by spring-pressed plungers 172 bearing on a collar 176 on the spindle. An insulating disc carrying three spaced contacts connected to a conductor ring 158 is keyed to the spindle 154 and is pressed by a spring 184 into engagement with three spaced contacts 94, 98, 114 and a sector contact 100, Fig. 3, embedded in an insulating disc 178 secured against a shoulder in the casing by a locking ring 182. The switch 112 comprises a casing 186 secured by rivets to the casing 148 carrying an insulating disc 190 in which are embedded contacts 192, 194, 196. A second insulating disc 198 having semicircular contacts 200, 202 embedded therein is secured by a stamping 208 to a spindle 206 carrying an actuating handle 204. In a modified switch construction shown in Fig. 21 the two switches are interlocked by a sliding bar 276 reciprocable between notched recesses in th bosses of the actuating members for the two switches. The selector switch handle 230 has a hollow boss 228 rotatably mounted on a fixed pin 218 and enclosing a contact plate 216 keyed to the boss by pins 232. The actuating cap 246 for the combined ignition and starter switch is rotatably secured to the fixed spindle by a headed member 250 having a screwed socket engaging a threaded part of the spindle 218. A contact plate rotatably mounted on the member 250 is keyed to the cap by pins 254. The reversing-gear may be of the kind shown in Fig. 19 in which 376, 378 are the driving and driven shafts respectively and each carry bevel wheels coupled by bevel wheels 380 mounted in a rotatable carrier. This carrier is adapted either to be held against rotation by a band brake 384 to give the reverse drive or to coupled by a clutch 386 to the driven shaft to give a solid forward drive. The control lever is coupled to the brake by mechanism, not shown, and to the clutch by a sliding wedge 388 acting through a bell-crank lever 390.