Patent GB-669982-A (GB)
Title: Improvements in friction clutches
IPC: F16D13/72
Filed: 1948-01-10
Abstract: 669,982. Friction clutches. BREEZE, C. A. Jan. 10, 1949 [Jan. 10, 1948], No. 836/48. Class 80 (ii). A friction clutch comprising at least one pair of co-acting driving and driven annular clutch elements 58, 59, Fig. 14, each having plane contact faces and surrounding an internal fluid space, is characterized by the provision, in the engaging face of one element 59, of fluid flow passages 56, Fig. 15, communicating directly with the space, and. in the other element 58, of outlet passages 55 which overrun the passages 56 during relative rotation between the elements 58, 59 so causing intermittent stoppage of fluid flow through the passages 56 and resisting and cushioning clutch engagement under applied pressure but which form continuations of the passages 56 and allow free fluid flow therethrough when the elements 58, 59 rotate in synchronism. As shown, the elements 58, 59 are respectively mounted on a driving disc 45 rigid with a shaft 41 and on a driven disc 46 freely mounted on the shaft 41, clutching pressure being applied by a spring 49 and relieved by a lever 52. The discs 45, 46 are surrounded by a fluid-tight chamber 53, in which a circulation of liquid through the passages 56, 55 is maintained centrifugally and by non-radial fins 64 on the disc 45, the liquid thrown out of the passages 55 being returned by a gutter 57 and ports 54 to the space between the discs. The elements 58, 59 may be integral with or detachably mounted on the discs 45, 46, and the contact face of the element 88 may be additionally formed with radial grooves. The spring engagement pressure may be wholly or partly replaced by centrifugally operated pressure means. In a modification, Fig. 18 (not shown), applied to a multi-plate clutch, the co-acting sets of clutch plates have fluid flow and outlet passages in the form of overlapping radial grooves in the respective clutch surfaces. In Fig. 22 (not shown), an apparatus similar to that of Fig. 8 of Specification 656,370, having air or liquid forcibly circulated between the clutch plates as by a pump, is employed, provided, if necessary, with an air vessel to smooth the pump delivery and having co-acting clutch surfaces of any of the following kinds. Mating clutch plates or detachable facings therefor C, D, Fig. 4, have overlapping grooves 18, 19 in their co-acting surfaces. The grooves 18 may be radial or curved, and of uniform or varying width. In Fig. 5, grooves 14 on one plate or facing surface open into a circumferential recess 16 leading.to shallow recesses 20 overlapping recesses 21 in the other plate or facing surface. In all cases the grooves may be of Vee, saw-tooth, semi-circular or other cross-section, and of uniform or varying depth. Fig. 6 shows intersecting radial and inclined grooves 22, 23 and 24, 25 on the respective plate or facing surfaces. In a further form of clutch, Fig. 12 (not shown), one annular clutch plate with a renewable facing has a rim projecting axially outside a co-acting annular plate also with a renewable facing, across the complete working surface of which extend radial grooves communicating with axial recesses extending partly across the outer periphery of the second plate and co-acting with radial outlet bores in the rim. The Provisional Specification described co-acting clutch elements of which one is similar to the element C, Fig. 4, with or without one or more circumferential recesses like the recess 16, Fig. 5, and the other may be similar to the first, have a plain surface, or possess merely radial surface grooves extending from the outer edge insufficiently to overlap the grooves in the first plate.