GB959287A - Improvements in and relating to friction clutches - Google Patents

Abstract

959,287. Overload release friction clutches. A. MAURER. Sept. 29, 1960 [Sept. 29, 1959], No. 33422/60. Heading F2C. In a friction clutch automatically disengaging on overload, wherein a friction disc 7 axially movable on pins 18 of'a clutch half 6 is gripped between a flange 4 of a clutch half 1 and a pressure plate 9 axially slidable thereon and urged thereto by manual rightward axial movement of a sleeve such as 2, Fig. 1, acting through a lever-like, slotted conical spring ring 11 which is fulcrumed on the flange 4 at 15 and determines clutch torque capacity, at least one retainer, such as 20, pivoted in the clutch half 1 and holding the sleeve 2 in the clutch engaging position by means of an abutment 22, is tilted against a spring 21 to release the sleeve for clutch disengagement by at least one tripping pin 25 which is mounted on the clutch half 6 and, on relative rotation of the two clutch halves, tiltingly engages a retainer nose 24. The ring 11 may be as described in Specification 689,432. As shown in Fig. 1, the single retainer 20, the nose 24 of which is substantially triangular in section, may be engaged by the single tripping pin 25, as shown, for automatic disengagement after maximum slip of one revolution, or by several such tripping pins for automatic disengagement after maximum slip of only part of one revolution. The clutch of this embodiment may be rendered arbitrarily engageable or disengageable by slightly inclining the abutment 22 and the complementary sleeve surface so that leftward sleeve shift, but not the force of the spring 11, may tiltingly cam the retainer 20. The presser plate 9 comprises, in screw-threaded engagement therewith, a ring 17 which provides means adjusting for wear and torque capacity. The sleeve is manually actuated through a control lever not shown and a non-rotatable collar 3. The automatic disengaging return of the control lever may be used to actuate an alarm switch and/or stop a driving motor. In Fig. 7, an arrangement permitting clutch engagement in any circumferential relation of the halves 1, 6; i.e. whether or not the tripping pin 25 engages a nose 24 or is sufficiently close thereto to tilt a retainer due to vibration, or whilst one of the clutch halves is rotating, two diametrically opposite retainers 20 must be successively tilted by one pin 25 to release the sleeve 2. To arrest an already tilted retainer until the other is tilted for release of the sleeve, a slotted spring ring 40, which is secured in the sleeve and is resiliently deformed by the engagement of the abutment 22 of at least one of the retainers and the sleeve in the clutch engaging position, springs back on tilting of the retainer to engage an inclined surface 23 thereof. In Figs. 10-13 (not shown), which embodiment is similar to that of Fig. 7, manual disengagement is provided by making the sleeve 2 in two concentric parts, one of which, the inner, acts on the spring ring 11 and comprises the arresting spring ring 40 and the other of which, the outer, actuates the inner part to engage the clutch when it is rightwardly shifted and has an inclined surface co-operating with the inclined surface 23 of the retainers so as to tiltingly cam the latter to release the clutch when it is leftwardly shifted. In Fig. 14 an outer part 90 of a two-part sleeve acts on the spring ring 11 and is held in its clutch engaging position by an abutment 106 of at least one of two retainers 100 pivoted by a spring ring 101 in the half 1 and outwardly urged by leaf springs 102. The tripping pin 105 acts to tilt the retainers inwardly to release the sleeve 90 for automatic clutch disengagement. The outer sleeve part 90 is spaced from a complementary inner sleeve part 80 so that when a retainer 100 is tilted by the tripping pin 105 the sleeve part 90 is canted over the relevant abutment 106 and arrests the retainer in its tilted position until the tripping pin 105 tilts the other retainer to permit clutch disengagement. For manual disengagement the inner sleeve part 80 has an inner tapered surface 81 co-operating with radial projections 108 on the retainers so as to tiltingly cam the latter to release the clutch when it is leftwardly shifted. In Fig. 9 (not shown) the retainer pivots about an axis parallel to that of the clutch.