Patent GB-571981-A (GB)
Title: Transmission dynamometers
IPC: G01L3/14
Filed: 1943-11-16
Abstract: 571,981. Dynamometers. HEENAN & FROUDE, Ltd., and WALKER, G. H. Nov. 16, 1943, No. 15235. Addition to 549,560. [Class 106 (ii)] The transmission dynamometer according to the parent Specification is modified by connecting the high and lower pressure chambers of the torque-transmitting elements to the torque-indicating gauge by means independent of the passages by which the circulating liquid is conveyed to and from the chambers. As shown, the driving means is coupled at B to a driving shaft A terminating in a spider with four equally-spaced arms a. The driven element is coupled at E to an annulus D having four inwardly-projecting arms d, forming with the arms a a series of chambers g<1>-g<8>, Fig. 2. Oil under pressure is supplied via connection s, port j<10>, and passage a<3> to four passages a<4> in the arms a, the ends of the passages a<4> communicating via arcuate slots d<3>, d<4> with the chambers g<1>-g<8>. The chambers g<1>-g<8> also communicate with passages a<5> (also Fig. 5, not shown), in the hub of the shaft A, the passages a leading away oil via passages a<2>, a<7> and R to the sump. When a torque is applied, the shaft A rotates relatively to the annulus D, the extent being limited by stops d<12>, Fig. 4, and the ports a<4> reduce or cut off connection to one set of chambers, say g<1>, g<3>, g<5>, g<7>, while supplying an increased amount of pressure fluid to the other chambers g<2>, g<4>, g<6>, g<8>. At the same time, the high-pressure chambers reduce or cut off their connection with the exhaust ports a<5>, which increase their communication with the low-pressure chambers. Further ports a<10> of smaller size than a<4> in the arms a (also Fig. 3, not shown) connect with the high-pressure chambers via suitable arcuate slots to lead a static pressure via passages a<11>, a<12>, j<12> and P<1> to the high-pressure side of a pressure gauge, while ports a<13> of smaller size than a<5> connect with the low-pressure chambers to lead a static pressure via passages a<14>, a<15>, j<5> and P<2> to the low-pressure side of the gauge. The ports a<10>, a<13> are of such size that they can communicate with only one chamber at a time, and in the position of no torque they are cut off completely. Measuring thrust.-Secured to the arms a are pairs of discs A<3>, A<4> and A<5>, A<6> shutting off end annular spaces s<1>, s<2> from the chambers g<1>-g<8> and enclosing the radial arms d with small endwise clearance. In the position of no thrust and no torque, ports q<3>, Figs. I and 6, in the member D lie between and just out of register axially and angularly with ports q<1>, q<2> in the discs A<4>, A<5>. At the transmission of torque and thrust, the discs rotate to bring one or other set of ports q<1>, q<2> into angular register with the ports q<3> according to the direction of rotation and the shaft A moves slightly endwise. This causes disc A‹ or A<3> to shut off the set of ports q<3> at the one end and to bring the ports q<3> at the other end into axial register with the appropriate ports q<1> or q<2> whereupon oil flows from the high-pressure chambers g<1>, g<3>, g, g<7> or g<2>, g<4>, g<6>, g<8> into the end space s<1> or s<2> to counteract the thrust. Leak holes s<3>, s<4> provide a restricted leak from the spaces s<1>, s<2> to the low-pressure chambers so as to prevent locking the elements A and D despite variations in thrust. The pressures in the spaces s<1>, s<2> are conducted along passages t<1>, t<2>, t<3>, j<8>, T<1> and t<4>, t<5>, j<7>, T<2> respectively to the two sides of a thrustmeasuring device. Oil leaking into spaces s<6> or s<5> at the end of shaft A or into sleeve J is returned to the sump via passages t<8> (Fig. 7, not shown) and T<5>, or j<15> and T<6>, respectively.