Patent GB-457761-A (GB)
Title: An improved gear ratio indicator and/or control device
IPC: G05G15/00
Filed: 1935-04-30
Abstract: 457,761. Facilitating changing speed; differential speed indicators. CONSTANTINESCO, G., Oxen House, Torver, Coniston, Lancashire. April 30, 1935, No. 12918. [Class 80 (ii)] [See also Group XIX] A gear ratio or slip indicator or synchronizer control device comprises two main shafts 26, 27, Fig. 1, drivingly connected in one or more ratios by means not shown and connected also in parallel through two friction rollers or the like 33 which are coupled by a differential gear train 28, differential turning of which causes screwing at 35 which causes the train to be displaced as a whole until it comes to rest in a position affording an indication as to synchronism, or as a step on the way to ensuring that a speed change shall be properly synchronized. Thus, the shafts 26, 27 might be geared to twin engines on an aeroplane or to electric alternators working in parallel, and would normally be rotating at equal speeds in the same direction. The rollers 33 would then be rotating at equal speeds in opposite directions and there would be no translation of the synchronizer. Any difference in speeds between these engines &c. would cause differential motion of the differential spider 29 and screwing between a screwed rod 30 which carries the spider and a fixed nut 35, so that translation of the synchronizer as a whole would start and go on until the synchronizer stops in a position in which the rollers 33 are again running at equal speeds, one nearer to and the other further from the centre of discs 24, 25 fast on the shafts 26, 27. If the power-transmitting gear train (not shown) connecting the shafts 26, 27 be belt or friction, slip of the belt or of the friction elements would be indicated and measured by consequential displacement of the synchronizer. The discs 24, 25 do not need to run at equal speeds, and if the speed of the main shaft 27 driven from the shaft 26 through a gear train (not shown) was one half the speed of the shaft 26, then the synchronizer would be screwed to the left of Fig. 1 and stop in a position which would indicate that if the gear train of ratio one half was not engaged, it might be engaged without shock. Figs. 2 and 3 show a preferred arrangement adapted for change-speed gearing in which main shafts 36, 37 are supported in line in a casing 38 and the rollers 42, 43 are loose on a fixed screwed rod 40 which is slightly oblique so that each roller touches one only of the discs 36<1>, 37'. The spider 45<1> of the differential is fast on the nut 45 which is free to screw on the fixed rod 40. A differential casing 41 slides between guides 48 and carries a spring electric contact-piece 46. When the drive is disengaged and the shafts in the gearbox are spinning freely relatively to one another, this relative spinning is reproduced between the shafts 36, 37, and the synchronizer keeps moving so that the contact-piece 46 sweeps over contact-pieces 47A, 47B, 47C on the fixed casing 38, which are connected in different circuits with different lamps or other indicating means. Thus, when the spring piece 46 contacts with the contact-piece 47A, a lamp shines to show that the gear ratio of the gearboxshafts is one half, and that gears transmitting that ratio may be engaged without shock. The currents thus set up may be used as described in Specification 457,850 to prevent a gear control lever being moved except at the right time. In Fig. 4 is shown an arrangement in which the friction gearing of the synchronizer is replaced by lever linkages. One main shaft is connected by a crank (not shown) to the free end 51<1> of a lever 51 pivoted at 51<11>, and the other main shaft is similarly connected to a lever 52 pivoted oppositely at 52". These levers oscillate arms 53, 54 which contain one-way grips which drive in opposite directions the two side members 55 of the differential, the spider 59 of which is fast on a rod 60 screwing into a fixed nut 61. Translation of the synchronizer continues as long as there is lack of synchronism, one of the levers 51, 52 getting shorter as the other gets longer until a balance is struck. Specification 415,808, [Group XXXI], also is referred to.