Cyclopedia of mechanical engineering; a general reference work Editor-in-chief Howard Monroe Raymond Assisted by a corps of mechanical engineers, technical experts, and designers of the highest professional standing . on the siulditinoss withwhich die clutch is thrown out. The force of friction is tlie sole drivinir element, hence the pnthlein is to secure asliirrre a force of frictionas possible. But frictioncannot be secured with-out a heavy normal pres-sure between surfaceshaving a high coefficientof friction between thcniThe many varieties ()ffriction clutches whichare on the market or de-
Cyclopedia of mechanical engineering; a general reference work Editor-in-chief Howard Monroe Raymond Assisted by a corps of mechanical engineers, technical experts, and designers of the highest professional standing . on the siulditinoss withwhich die clutch is thrown out. The force of friction is tlie sole drivinir element, hence the pnthlein is to secure asliirrre a force of frictionas possible. But frictioncannot be secured with-out a heavy normal pres-sure between surfaceshaving a high coefficientof friction between thcniThe many varieties ()ffriction clutches whichare on the market or de-signed for some specialpurpose, are all devicesfor accomplishing oneand the same effect, vis.,ti the production of a heavynormal force or pressurebetween surfaces at sucha radius from the drivenaxis, that the product ofthe force of frictionthereby created and theradius shall equal thedesired twisting momentabout that axis. Three ty[)ical meth-odsof accomplishing thisare shown in Figs. 48,49, and 50. None ofthese drawings is workedout in operative are merely illus-trations of principle, and are drawn in the simplest form for thatpurpose. In Fig. 48 the normal pressure is created in the simplest pos-. MACHINE DESIGN 141 sible way, an absolutely direct push being exerted between thediscs, due to the thrust P of the clutch fork. In Fig. 49 advantage is taken of the wedge action of the; in-clined faces, the result be-ing that it takes less thrustP to produce the requirednormal pressure at the ra-dius K. In Fig. 50 the inclin-ation of the faces is carriedso far that the angle a ofFig. 49 has become zero;and by the toggle-joint ac-tion of the link pivoted tothe clutch collar, the nor-mal force produced may beverygreatfor a slight thrustP. By careful adjustmentof the length of the link sothat the jaw takes hold ofthe clutch surface, whenthe link stands nearly ver-tical, a very easy operatingdevice is secured, and thethrust P is made a mini-mum. THEORY. Eeferringto Fig. 4S i
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmechanicalengineerin
