Electricity: motive power systems – With particular motor-driven load device – Power- or motion-transmitting mechanism
Reexamination Certificate
2000-05-30
2001-10-09
Nappi, Robert E. (Department: 2837)
Electricity: motive power systems
With particular motor-driven load device
Power- or motion-transmitting mechanism
C318S007000, C318S008000, C180S006500, C180S065100, C180S065230, C280S250100, C297S073000, C297S423320
Reexamination Certificate
active
06300732
ABSTRACT:
The present invention relates to a power unit of the type employed for movement of a back and a footrest in armchairs and the like.
Known in the art are power units called “dual motors” which are formed of a generally elongated rectangular casing comprising, at the inside thereof, two motor reducers and two transmission-gears for rotation of a pair of movement shafts. Connected to one of these shafts is the kinematic movement mechanism of the armchair back and to the other of said shafts the kinematic movement mechanism of the armchair footrest.
Accomplishment of the power units is made complicated by the fact that they must be very powerful, strong and compact.
In the art it has been proposed that the transmission-gear between each motor reducer and the movement shaft should be accomplished by means of a mechanical piston formed of a screw connected to the motor reducer, and the free end of which is received in a sliding element. In this way, upon rotation of the screw, the screw-slidable element assembly is made longer and shorter. The movement shaft is integral with a cam which is disposed in a plan coincident with the screw axis and bearing on the head of the sliding element. In this manner on lengthening and shortening of the piston, the movement shaft rotates. An example of these devices is disclosed by EP-A-0 583 660.
A drawback of such a structure is that the piston, in order to supply a sufficient rotation angle of the movement shaft, must nearly double its length when it passes from the retracted condition to the completely extended condition. For the above reason the longitudinal sizes of the power unit are relatively high. In addition, even when a greater rotation angle would be preferable, this is not possible because it would involve accomplishment of a too long power unit, incompatible with the armchair sizes.
It is a general object of the present invention to obviate the above mentioned drawbacks, by providing a compact, cheap and strong power unit enabling high rotation angles with a reduced bulkiness to be obtained.
In view of the above object, in accordance with the invention, a dual power unit has been devised for movement of a back and a footrest in a power-driven armchair comprising an elongated casing which, close to each end, has a transverse-movement shaft which is connected to a shaft of an electric motor reducer through a transmission-gear, the transmission-gear comprising a screw connected to the shaft of the motor reducer and extended transversely of the movement shaft and longitudinally of the casing and a threaded slding slider into which the screw is screwed down, cam means being integral with the movement shaft and bearing on the slider for converting the sliding movement of the slider along the screw into an angular-rotation movement of the DE-U 94 17 433 discloses a power unit, wherein a crank-rod mechanism converts the linear movement of a slider rotational movement of the shaft. movement shaft, characterized in that the screw thoroughly crosses the slider and in that the cam means comprises two cam elements laterally projecting from the movement shaft for resting on thrust surfaces provided on the slider, on opposite sides of the screw.
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patent: 3596154 (1971-07-01), Gurwicz
patent: 4475072 (1984-10-01), Schwehr et al.
patent: 5044647 (1991-09-01), Patterson
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patent: 5450800 (1995-09-01), Leonard
patent: 5667035 (1997-09-01), Hughes
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patent: 5894097 (1999-04-01), Peter
patent: 5927144 (1999-07-01), Koch
patent: 6176335 (2001-01-01), Schaffner et al.
patent: 9417433 (1995-05-01), None
patent: 583 660-A1 (1994-08-01), None
Compact S.r.l.
Nappi Robert E.
Shlesinger Fitzsimmons & Shlesinger
Smith Tyrone
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