Patent GB-298523-A (GB)
Title: Improvements in and relating to control mechanisms
IPC: H01C10/50
Filed: 1927-07-08
Abstract: 298,523. Volk, C. Juy 8, 1927. Controlling consuming devices.-In a control mechanism enabling up to four variables to be controlled simultaneously, a universally-jointed lever actuates two or three single radial control members which pass away from it through fixed points arranged relatively close to the joint so that the control members are fully actuated by lateral movements of the lever relatively to the fixed points as well as by straight line movements of the lever in the lines of the control members, and the fixed points are located in a compact self-contained unit. Rotation or longitudinal movement of the lever may actuate independently a fourth control, or be arranged to affect the first three variables either arithmetically or geometrically. The control members may actuate the variables directly, or through multiplying or reducing gears, or through remote control devices, and they may actuate or carry indicators sholwing their adjustments. The lever may be operated by hand, or automatically according to a prearranged cycle, and the apparatus may be employed for controlling white or coloured lighting for photographic studios, shop windows, theatrical, advertising, and like purposes, or the apparatus may be duplicated for the purpose of comparing colours. In the form shown in Figs. 1 and 3, three flexible cords 13 are secured to a universally-jointed lever 1 and pass away through eyes 14 at fixed points R, G, B, which are the centres from which are struck the circular arcs which form the sides 3 of a substantially triangular gate adapted to control the movement of the lever 1 about its joint 2. The members 13 are secured to gravity- or spring-operated sliders 11 mounted on guides 12 so as to travel over dimmer resistances 10 adapted to control the current supplied to bulbs in the compartments 5, 6, 7, Fig. 4, of a box like light-projector 4. The compartments 5, 6, 7 are fitted with detachable lids carrying gelatine, glass, or other differently coloured transparencies. The projector 4 is also provided with elongated compartments 8 fitted with preferably "daylight" bulbs. The cords 13 may be replaced by rigid members such as linkages, or racks and pinions, and instead of an actual gate, a virtual gate may be formed by means of stops on the radial members. Also, the eyes 14 may be replaced by pairs of cylindrical rollers 40, Fig. 7, mounted on spindles 41 bolted to the gate 3 parallel with the mid-position of the lever 1, and pulleys 42 on spindles 43 carried in brackets 44 secured to the gate. The. lever 1 is provided with a rotatable handle 15 which operates bevel gears 16 to rotate a shaft 17 within the lever 1 and having a universal joint 19 with the same centre as the joint 2. A pinion 20 on the shaft 17 operates a drum and cord, rack, or chain 21, which engages the pinions 22 of pivoted louvre shutters 9. The pinions 22 are only partly toothed so that the louvres of compartments 5, 6, 7 operate in advance of those of compartment S. Instead of louvre shutters, a roller shutter adapted to be pulled completely over the compartments 5 - - 8 may be employed, or the shaft 17 may be arranged to control a master dimming resistance which simultaneously and proportionately affects all the bulbs in the compartments 5 - - 8. The apparatus may be provided with a cut out switch which may be mounted on the handle 15, or be in the form of a foot pedal switch. 23. Means may be provided to lock the lever in any particular position. In the form shown in Fig. 9, the lever 1 has a brake member 45 normally urged axially of the lever by a spring 46 to coact with a spherical surface 47 concentric with the joint 2, and released through a Bowden-wire mechanism by a thumb or hand actuated device on the handle 15. A ball and socket universal joint with a clamping socket may be controlled in a similar manner. The control members may actuate the variables step by step. In the form shown in Fig. 10, the control members may rotate a shaft 48 carrying a wheel 49 in engagement with a pinion 55 connected to the variable. The wheel 49 is secured to the shaft 48 by a lostmotion device, such as a key 50 and a wider keyway 51, and the teeth on the wheel 49 are engaged by a roller 52 on a spring-pressed blade 53. Alternatively, a ratchet may be employed.