Accouplement à autorenforcement

摘要

1,068,641. Ratchet clutches; friction clutches. G W. SEIFERT. Jan. 15, 1965 [Jan. 15, 1964; April 18, 1964], No.1990/65. Heading F2C. A self-tightening friction clutch has full engagement pressure produced by a nut running on a coarse thread, and a spring is interposed between the nut and a friction element or pressure plate of the clutch. As shown in Fig. 1 a nut 10 engages threads 2 on a driving- shaft 1 and carries a laminated spider spring 12 which is retained within recesses 13 of a driving friction disc 9 by means 14. Stops 3, 4 limit the disengaged and engaged positions for the nut 10, a spring 11 normally maintaining the nut fully disengaged against the stop 3. The friction disc 9 is brought into light frictional engagement with a driven clutch part 5 by any suitable means, the nut 10 then screwing along the shaft 1 to give full engagement. In a modification the nut 10 may be retained in its fully engaged position by providing it with a sleeve having a ball containing aperture, the ball engaging a groove in the shaft 1 when the nut is against the stop 4 and being retained in the groove by a locking sleeve. Fig. 4 shows a multiplate friction clutch having a nut 10 connected to a presser plate 42 by a spider spring 12. Fig. 5 shows an arrangement for driving an engine cooling fan 69. In this case the nut 10 engages threads on a member 10a adjustably positioned on a driving shaft 1 and the nut carries a spider spring 12 bearing against a friction disc 9 which is secured to bolts 67 on an axially displaceable housing 64. The housing 64 is secured to the periphery of a bimetallic plate 56 the inner periphery of which is retained against the shaft 1 by the head of a screw 55. In operation the shaft 1 is continuously rotated, the bimetallic plate 56, housing 64 and clutch disc 9 rotating therewith. When the temperature of the air stream coming from the radiator rises to a predetermined value, the bimetallic plate is deflected and shifts the housing 64 axially and engages the disc 9 with a friction element of the clutch part 5. The initial light engagement is augmented by screwing of the nut 10; if the temperature falls the bimetallic plate 59 resumes its initial configuration and the spring 12 relaxes. The clutch then opens when the fan 69 overruns the driving shaft 1.