US 6,547,216 B1Granted

Multiple balls supported push actuator

AssigneeGestion Laforest Inc.

InventorsPaul-André Bouchard, Pierre Laforest, Pierre Gagnon, Alain Forté

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Abstract

The push actuator has a fixed base which rotatably carries a selectively rotatable rotor. A horizontal band has a lower portion stacked in a helical pattern and has an upper portion engaged by the upper portion of a vertical band, to form a telescopic column. The lower portion of the vertical band is stacked in a spiral, separately from the horizontal band, the horizontal band is supported on the rotor with a helical ball support track along which a number of balls can roll and slide, to allow substantially frictionless rotation of the rotor member while the horizontal band remains rotatably stationary. A ball re-circulation unit allows the balls to circulate between the top of the track and the bottom of the track. Upon rotation of the rotor, the vertical column is formed by the horizontal band being lifted and its turns being spaced through its engagement on the rotating helical ball support track, and by each turn of the vertical band being inserted between two vertically successive turns of the horizontal band.

Claims16

Dependent claims

A telescopic tube comprising:

a first annular band wound in helical form about a central axis with its turns transversely normal to said central axis and capable of taking a retracted stacked position with its turns resting flat against one another, and an extended position with its turns spaced from one another in the direction of said central axis;
a second band wound on itself, with its turns transversely parallel to said central axis and capable of taking a retracted, spiral position with its turns nested within one another and an extended position with its turns forming a helix around said central axis and generally equally radially spaced therefrom to form a tube, said first and second bands, when in retracted position, being in respective locations so as to clear each other;
a frame having a base resting on the ground and a rotor rotatably carried by said base;
a continuous frictionless support member carried by said rotor and forming at least a portion of a helix for supporting part of said first band, and for successively spacing the turns of said first band;
a power device, to cause relative rotation of said first band and of said rotor about said central axis, said continuous frictionless support member allowing the axially oriented load of said push actuator to be transmitted from said first band to said rotor while allowing a substantially frictionless relative rotation of said first band and said rotor;
and
a guiding member to insert the turns of the second band between the spaced turns of the first band, with the edges of the turns of the second band bearing against the turns of the first band, the second band thus forming a spacer for the turns of the first band.

4 more elements

A push actuator having opposite first and second ends and an intermediate portion between said first and second ends, said push actuator further defining a central axis extending between said first and second ends and comprising:

a fixed base portion at said first end;
a rotor member rotatably carried by said base portion and rotatable about said central axis;
a power device, for selectively rotating said rotor member relative to said base portion;
a load-bearing member at said second end, movable relative to said first end, between a retracted position in which said load-bearing member is adjacent to said first end, and an extracted position in which said load-bearing member is distally located relative to said first end;
a first flat band being perpendicular to said central axis, being wound according to a helical pattern about said central axis, and having a first end portion adjacent said push actuator first end and a second end portion attached to said load-bearing member;
a second flat band being parallel to said central axis, being wound according to a helical pattern about said central axis, and having a first end portion adjacent said push actuator first end and a second end portion attached to said load-bearing member;
a continuous frictionless support member with at least a portion thereof being wound in a helical pattern about said central axis, with part of said first helical band engaging said continuous frictionless support member allowing substantially frictionless rotation of said rotor member relative to said first band;
and
a guiding member at said push actuator intermediate portion and carried by said rotor member, for guiding said second band so as to place each turn of each one of said first and second bands between two successive turns of the other one of said first and second bands between said intermediate portion and said second end when said rotor member is rotated in a first direction around said central axis, thus forming a telescopic column composed of the interconnected first and second bands with the edges of the turns of the second band bearing against the turns of the first band, and with said first and said second bands each being independently stackable between said intermediate portion and said first end.

6 more elements

Dependencies are inferred from the claim text.