Lift device

Claim 2

A lift device comprising a vertical column securable on a support surface, a support frame movably secured along at least a portion of said column, a driveable drum secured in an upper part of said column, a drive assembly including a drive motor coupled to said drum, at least one cable secured to said drum and said support frame and of sufficient strength to displace said support frame and load thereon along said column when said drum is rotated, an elongated bolt supported adjacent said column for free axial rotation, said bolt having a helical thread along at least a portion thereof, and a connector secured to said support frame and is in threaded engagement with said bolt, said bolt supporting said support frame when said at least one cable fails to support said support frame.

Claim 3

A lift device as claimed in claim 1, wherein said column comprises a steel beam having an elongated flat wall, said support frame being connected to said flat wall by support wheels positioned on a front and back side of said flat wall, said support frame having at least one support arm extending transverse to said vertical column.

Claim 4

A lift device as claimed in claim 2, wherein said support frame further comprises a U-shaped attachment bracket defining opposed parallel side walls and a transverse connecting wall, said support wheels being roller bearings secured transverse to a respective one of said side walls and in contact with said front and back side of said flat wall whereby said attachment bracket is captive and displaceable on said flat wall by said roller bearings, said at least one support arm being pivotally secured to said transverse connecting wall.

Claim 5

A lift device as claimed in claim 3, wherein said at least one support arm is a telescopic extensible support arm having a horizontal support bracket at a free end thereof.

Claim 6

A lift device as claimed in claim 2, wherein said drive assembly further comprises a gear reduction mechanism coupled to said drive motor and said drum, said drum being secured to a shaft having a toothed drive gear which is chain coupled and driven from an output toothed gear of said gear reduction mechanism in a manner whereby the r.p.m. of said motor to said toothed drive gear is greatly reduced.

Claim 7

A lift device as claimed in claim 5, wherein said drum has three steel cables secured thereto, the free end of each said cables being secured to said support frame, said cables being secured in spaced-apart relationship on said drum whereby said cables are wound on said drum simultaneously, said cables being of sufficient tensile strength to lift at least the maximum load to be lifted by said support frame.

Claim 8

A lift device as claimed in claim 1, wherein there is further provided a further vertical column securable on said support surface, a further support frame movably secured along said further column, a further cable secured to said support frame and extending to said further column by engaging a guide pulley in a base of each column, a top pulley in an upper part of said further column, said further cable extending upwardly along said further column and about said top pulley and then downwardly to be secured at its free end to said further support frame whereby both said support frames will be displaced simultaneously at a substantially equal rate and in substantially horizontal alignment along their respective column by said drum when rotated.

Claim 9

A lift device as claimed in claim 7, wherein said top pulley is secured in a bracket which is adjustably secured to said further column for vertical displacement whereby to maintain said further cable taut.

Claim 10

A lift device as claimed in claim 8, wherein there are two of said further cables each of which extends side-by-side, said guide pulleys and top pulley being double-grooved to guide each of said two further cables.

Claim 11

A lift device as claimed in claim 8, wherein said further cable has opposed ends thereof secured to said further support frame thus forming a loop to define two side-by-side cable length sections and an integral end, said guide pulley and top pulley being double-grooved to guide each of said cable length sections, said integral end being looped about an attachment post secured to said support frame.

Claim 12

A lift device as claimed in claim 7, wherein said columns are secured in spaced-apart relationship on said support surface to permit a passenger vehicle to be positioned therebetween on said support surface, said further cable extending under said support surface in a cable housing and displaceable longitudinally therein, said support frame of both columns being capable of engagement of said vehicle from the underside thereof and said columns being of sufficient height to cause said vehicle to be lifted between said columns to a height sufficient to permit a person to walk thereunder.

Claim 13

A lift device as claimed in claim 1, wherein a portion of said bolt extends through a support bracket secured to said column, a support plate secured to said bolt and disposed above a support face of said support bracket, said support plate resting on said support face and supporting said bolt and the load on said support frame when said at least one cable fails to support said support frame.

Claim 14

A lift device as claimed in claim 12, wherein said support plate is a circular support disc having a friction surface on a lower face thereof, said support face of said support bracket being on engageable disc having an upper flat surface, a separator coil spring positioned about said portion of said bolt extending through said support bracket to maintain said friction surface above and spaced from said upper flat surface of said engageable disc.

Claim 15

A lift device as claimed in claim 13, wherein said connector is a hollow open-ended housing, thread engaging means secured in said open-ended housing and in threaded engagement with said bolt, said connector transferring the load of said support frame onto said bolt when said cable fails to support said support frame whereby said bolt which be displaced axially downward and compress said separator coil spring with said friction surface brought in contact with said upper flat surface of said engageable disc, said support disc being given a rotational torque by the load on said support frame acting on said bolt through said thread engaging means whereby said support frame will be displaced a short distance downwardly in a damped manner when said cable fails to support said support frame and its load.

Claim 16

A lift device as claimed in claim 14, wherein said thread engaging means is at least two diagonal bolts havinga thread engaging free end in close frictional contact between opposed side walls of the thread of said bolt.

Claim 17

A lift device comprising a vertical column securable on a support surface, a support frame movably secured along said column, a drive assembly including a drive motor coupled to said support frame for displacing said support frame along said column, a safety mechanism secured adjacent said column, said safety mechanism having an elongated bolt with a helical thread along at least a portion thereof, said bolt being supported adjacent said column for free axial rotation, and a connector secured to said support frame and in threaded engagement with said bolt, said bolt supporting said support frame when said drive assembly becomes uncoupled to said support frame.

Claim 18

A lift device comprising a vertical column securable on a support surface, a support frame movably secured along said column, a drive assembly including a drive motor coupled to said support frame for displacing said support frame along said column, a safety mechanism secured adjacent said column, said safety mechanism having an elongated bolt with a helical thread along at least a portion thereof, said bolt being supported adjacent said column for free axial rotation, and a connector secured to said support frame and in threaded engagement with said bolt, said bolt supporting said support frame when said drive assembly becomes uncoupled to said support frame.

Claim 19

A lift device as claimed in claim 16, wherein a portion of said bolt extends through a support bracket secured to said column, a support plate secured to said bolt and disposed above a support face of said support bracket, said support plate resting on said support face and supporting said bolt and the load on said support frame when said drive assembly becomes uncoupled from said support frame.

Claim 20

A lift device as claimed in claim 17, wherein said support plate is a circular support disc having a friction surface on a lower face thereof, said support face of said support bracket being an engageable disc having an upper flat surface, a separator coil spring positioned about said portion of said bolt extending through said support bracket to maintain said friction surface above and spaced from said upper flat surface of said engageable disc.

Claim 21

A lift device as claimed in claim 18, wherein said connector is a hollow open-ended housing, thread engaging means secured in said open-ended housing and in threaded engagement with said bolt, said connector transferring the load of said support frame onto said bolt when said drive assembly becomes uncoupled from said support frame whereby said bolt will be displaced axially downward and compress said separator coil spring with said friction surface brought in contact with said upper flat surface of said engageable disc, said support disc being given a rotational torque by the load on said support frame acting on said bolt through said thread engaging means whereby said support frame will be displaced a short distance downwardly in a damped manner when said drive assembly becomes uncoupled from said support frame.

Claim 22

A lift device as claimed in claim 19, wherein said thread engaging means is at least two diagonal bolts having a thread engaging free end in close frictional contact between opposed side walls of the thread of said bolt.

Claim 23

A lift device as claimed in claim 16, wherein there is further provided a further vertical column securable on said support surface, a further support frame movably secured along said further column, drive coupling means between said columns to displace said further support frame whereby both said support frames will be displaced simultaneously at substantially equal rate, and in substantially horizontal alignment, along their respective column by said drive assembly.