Patent GB-1014304-A (GB)
Title: Improvements in or relating to electro-magnetically actuated braking and coupling device
IPC: F16D59/02
Filed: 1962-06-25
Abstract: 1,014,304. Electromagnetically operated brake; friction and positive clutches; roller shafts. N. RIEDEL. June 23, 1962 [June 23, 1961; Oct. 14, 1961], No. 24397/62. Headings F2C, F2E and F2U. A torque-transmitting device comprises a rotatable shaft 1 carrying a torque-transmitting member which can couple the shaft to a torqueabsorbing member 3 and a stationary electromagnet 16, 17 for operating the device in opposition to a spring 11, there being included in the transmitting device a power-amplified coupling device (Fig. 4) including a locking arrangement (Fig. 3) for disengaging and engaging a rotatable wedge 5 which is connected to the device between the said torque members and the electromagnet. The shaft 1 has an axial bore 4 housing the end of the rotatable wedge 5 and radial bores housing balls 37. The wedge 5 has radial bores at its end housing balls 22 which rest inwardly on a conical drawwedge 13 on a shaft 15 connected to the armature 17. The balls 22 are encircled by a ring 25 which has an hexagonal outer periphery and recesses 26 in its inner periphery into which the balls 22 engage when the electromagnet is operated to draw the wedge 13 outwards of the recess 8. Balls 28 in a carrier 29 are normally located centrally of each face 27 of the hexagon but when entry of the balls 22 into the recesses 26 locks the wedge 5 to the shaft 1, the balls 28 ag relative to the consequent movement of the haft and are jammed between the faces 27 and spring-loaded segments 30 which act as shock absorbers. Rotation of the wedge 5 causes the balls 37 to enter recesses 39 in a ring 40 which surrounds them, whilst other balls 42 are, in consequence of the resulting rotation of the ring 40, jammed between flats 41 on it and a surrounding ring 43 so that the latter also rotates. The octagonal outer periphery of the ring 43 carries one set of discs of the brake 47 whilst the other set are mounted in an extension 2 of the member 3. Pressure between the sets of discs is adjustably maintained (Fig. 10, not shown) by a spring washer 60 of which the angle of pitch may be altered by a clamping ring of variable diameter. In the embodiment shown in Fig. 7 the ball assemblies 42 and 37 of Fig. 1 are replaced by a set of rollers 61 which are entrained by members 64 attached to the shaft 1. When the wedge 5 rotates it moves the rollers 61 outwards to clamp them against ramps 70, or 71, depending on the direction of rotation, which are formed on the inner side of jaw segments 63 surrounding the rollers. The rotation thereby received from the shaft 1 is transmitted from the jaws 63 through split rings 72, 74 to a sleeve 60 which carries one half of the discs of the brake 47. The ends of the rings 72, 74 engage against a projection 73 on one of the jaws. They absorb the shock of the engagement of the rollers. The ring 74 is of bronze and has oil-fillable perforations 75. In this embodiment the draw wedge 77 is allowed a limited axial movement along a reduced portion of the draw-rod 79 which, in combination with the special shape of the wedge, causes it to snap in and out of engagement with the balls 22.