Patent GB-944662-A (GB)
Title: Clutch
IPC: F16D47/02
Filed: 1960-03-07
Abstract: 944,662. Friction clutches; controlling clutches; overload-slip couplings. BORGWARNER CORPORATION. March 7, 1960 [March 11, 1959], No. 8022/60. Headings F2C, F2L and F2U. A friction clutch comprises a sprag carried by a driving clutch member and rotatable about an axis parallel to the main clutch axis to engage frictionally with a driven sleeve, the clutchengaging movement being obtained by the projection of a stop into the path of travel of the sprag which is linked to a lever engaged by the same stop to disengage the clutch. In one form, a driving pulley 11, Fig. 1, is fast with a sleeve 12 to which is secured a plate 18 connetted by rivets 36, 38 to a spaced plate 34, two sprags 54, 78; Fig. 2, pivoting about the rivets 36, 38 and also being pivoted upon an intermediate linking plate 94 movable radially by virtue of a hole 96 transversely to the axis of the clutch. A driven sleeve 60 is rotatable upon a bushing 62 carried by the driving sleeve 12, and is secured to a driven pulley 68. The sprag 54 is formed with a cam surface 58 which, as shown in Fig. 3, can be engaged frictionally with the surface of the sleeve 60 to transmit drive thereto. The corresponding cam surface 58 upon the sprag 78 is disposed radially away from the driven sleeve 60, so that it never engages therewith. A stop disc 124 can be slidden axially into the radial paths of tabs 86, 98 upon the sprags 54, 78, respectively. In the position shown in Fig. 2, the sprags 54, 78 are so positioned that the tab 98 on the sprag 78 describes a larger circular path as the driving pulley 11 &c. rotates, than does the tab 86 on the end of the sprag 54. The clutch is now disengaged. By introducing the stop disc 124 into the path of the tab 98, the sprag 78 is pivoted about the rivet 38 as the clutch rotates, and accordingly draws the linking plate 94 transversely downwards of Fig. 2. The sprag 54 is thereby simultaneously turned about its rivet 36, and the cam surface 58 thereon is engaged with the surface of the driven sleeve 60 for torque transmission. To disengage the clutch, the stop disc 124 is moved axially of the clutch into the path of the tab 86 on the sprag 54, which has now taken up the position shown in Fig. 3. The sprag 54 is turned by the rotation of the clutch when it contacts the stop disc 124, and its cam surface 58 is moved out of engagement with the driven sleeve 60. Bouncing of the sprags 54, 78 when the clutch is disengaged is prevented by bending the edge 93 of the linkage plate 94, so that it engages frictionally with the driveplate 18. Control of the axial position of the stop disc 124 is effected by a solenoid 102 energized to attract an armature 118 against the bias of a spring 128. In a modified form, a sleeve 138, Fig. 6, driven through a similar clutch, is provided with a radially outwardly turned flange 140 between two friction rings 180 biased into engagement therewith by a Belleville spring 182 lying between the hub of a driven pulley 146 and a disc 172, the whole forming an overloadslip coupling. A radial tab, Fig. 4 (not shown), on the disc 172 projects through a slot in the hub of the pulley 146 to prevent relative rotation therebetween, and the friction rings 178 are prevented from moving radially by tabs 190 pressed out from the hub of the pulley. In another modification, Figs. 7, 8 (not shown), the sprags pivot on rivets passing through a solid pulley corresponding to the driving-plate 18 of Fig. 1, and the clutch is normally disengaged but is momentarily engaged to transmit drive to a pump (not further described).