초록 ▼

A lift assembly that can be reversibly installed in the bed of a pick-up truck or other flat bed transport means. At least four telescoping support legs are disposed at the four corners of the truck bed and support the upper rails on which the load is placed. The support legs are made up of a series

A lift assembly that can be reversibly installed in the bed of a pick-up truck or other flat bed transport means. At least four telescoping support legs are disposed at the four corners of the truck bed and support the upper rails on which the load is placed. The support legs are made up of a series of nested threaded segments driven by a similarly threaded drive shaft. A reversible motor associated with each support leg enables the segments to rotate in a forward direction to raise the load and to rotate in the reverse direction to lower the load. The motors are activated simultaneously and powered by the truck battery. The raising and lowering motion is smooth and continuous and can be stopped at any desired height. The lift assembly enables the height of the load to be easily changed by one person without any disturbance or shifting of the load. Telescoping braces are available to stabilize the support legs when fully extended and protective sleeves can be used to eliminate damage to the mechanism from environmental contaminants.

대표청구항 ▼

1. A rack lift assembly, for use with pick-up trucks, flat bed trucks and trailers having a horizontal cargo bed, and being capable of raising and supporting an elevated utility rack, said lift assembly comprising:at least four telescoping support legs, each situated at a corner of the cargo bed, ea

1. A rack lift assembly, for use with pick-up trucks, flat bed trucks and trailers having a horizontal cargo bed, and being capable of raising and supporting an elevated utility rack, said lift assembly comprising:at least four telescoping support legs, each situated at a corner of the cargo bed, each of said support legs comprising;a series of nested rotatable cylindrical segments, an outer first segment and at least one inner second segment, said first segment being smooth on its exterior surface and having at least two threads situated at the bottom of its interior surface, and said second segment being threaded on its exterior surface, having a stop means at the top of its exterior surface and a stop means at the bottom of its exterior surface, and having at least two threads situated at the bottom of its interior surface, said stop means for preventing said segments from becoming dissociated;a canister for containment of said segments;a support frame to support said canister on the cargo bed;a drive shaft to rotate said segments, said drive shaft being positioned axially within the nested segments, being threaded for substantially the upper three fourths of its length, and having a stop means at its top and another stop means situated below the threads, said stop means for preventing the drive shaft from becoming dissociated from said segments;said threads on said segments and said drive shaft being of the same dimensions for cooperation therebetween;means to rotate the drive shaft in a forward direction and in a reverse direction; anda top cap to which the rack is affixed;whereby when a utility rack is supported on the four support legs and the rotation means causes the drive shafts to be rotated in the forward direction the segments rotate in the forward direction and move upward such that the support legs telescope upward raising the utility rack, and when the rotation means causes the drive shaft to be rotated in the reverse direction the segments rotate in the reverse direction and are moved downward such that the support legs are collapsed and the utility rack is lowered. 2. A rack lift assembly as in claim 1 wherein stop means on the second segment and on the drive shaft are collars. 3. A rack lift assembly as in claim 2 wherein the collars are dimensioned such that their depth is the same as the depth of the threads. 4. A rack lift assembly as in claim 1 wherein the diameters of the nested segments decrease incrementally. 5. A rack lift assembly as in claim 4 wherein as the diameters of the nested segments decrease incrementally the lengths of the nested segments increase incrementally. 6. A rack lift assembly as in claim 1 wherein the canister is cylindrical. 7. A rack lift assembly as in claim 1 wherein the canister further comprises a horizontal bearing plate affixed near its lower interior edge, said bearing plate having a central aperture through which the drive shaft passes. 8. A rack lift assembly as in claim 7 further comprising a bearing situated above the bearing plate and being adjacent thereto. 9. A rack lift assembly as in claim 7 further comprising a bearing situated below the bearing plate and being adjacent thereto. 10. A rack lift assembly as in claim 1 further comprising means to reversibly affix said support frame to the cargo bed. 11. A rack lift assembly as in claim 1 wherein the means to rotate the drive shaft comprises:a key seat disposed on the lower portion of the drive shaft,a motor capable of operating in a forward and in a reverse direction,a first pulley rotated by said motor,a belt rotated by said first pulley,a second pulley rotated by said belt, said second pulley being in communication with the drive shaft and having an aperture dimensioned to accept the key seat. 12. A rack lift assembly as in claim 11 wherein the first pulley and the second pulley are Browning pulleys. 13. A rack lift assembly as in claim 12 wherein the belt is a Browning belt. 14. A rack lift assembly as in cla im 11 further comprising a housing to contain said motor. 15. A rack lift assembly as in claim 11 further comprising a motor mount to support said motor. 16. A rack lift assembly as in claim 15 further comprising means to adjustably affix said motor mount to the support frame. 17. A rack lift assembly as in claim 1 wherein the threads situated on the first segment, the second segment and the drive shaft are all Acme 5 threads. 18. A rack lift assembly as in claim 1 wherein the top cap is cylindrical. 19. A rack lift assembly as in claim 18 wherein the top cap further comprises a flat top member, at least one plate bearing situated under the flat top member, and a bearing locator centrally affixed to the underside of the flat top member, whereby the bearing is rotatable with the segments and the top cap does not rotate with the segments. 20. A rack lift assembly as in claim 19 wherein the flat top member further comprises at least one attaching member for securing the utility rack to the support leg. 21. A rack lift assembly as in claim 1 further comprising protective sleeves which are capable of completely enclosing each support leg and protecting the support legs from undesirable outside conditions. 22. A rack lift assembly as in claim 21 wherein the protective sleeves are composed of flexible material such that they can expand as the support legs are telescoped upward and can contract as the support legs are collapsed. 23. A rack lift assembly as in claim 1 further comprising telescoping brace means affixed to the top cap and canister of each support leg for providing bracing and stability to the support legs when fully extended. 24. A rack lift assembly as in claim 23 wherein the brace means comprises a series of nested segments and a base segment dimensioned to contain the nested segments. 25. A rack lift assembly as in claim 24 wherein each of the nested segments further comprises stop means to prevent the segments from becoming dissociated. 26. A rack lift assembly as in claim 25 wherein the stop means comprises a vertical slot and a stop knob. 27. A rack lift assembly as in claim 24 wherein the nested segments are square in cross section. 28. A rack lift assembly as in claim 23 further comprising protective sleeves which are capable of completely enclosing each brace means and protecting the brace means from undesirable outside conditions. 29. A rack lift assembly as in claim 28 wherein the protective sleeves are composed of flexible material such that they can expand as the brace means are telescoped upward and can contract as the brace means are collapsed. 30. A lift assembly for smoothly raising and lowering a load, said lift assembly comprising:a series of nested rotatable cylindrical segments, an outer first segment being smooth on its exterior surface and having at least two threads situated at the bottom of its interior surface, at least one inner second segment being threaded on its exterior surface, having a collar about the top of its exterior surface and a collar about the bottom of its exterior surface and having at least two threads situated at the bottom of its interior surface;a canister for containment of said segments;a support frame to support said canister on a horizontal surface;a drive shaft to rotate said segments, said drive shaft being positioned axially within the nested segments, being threaded for substantially the upper three fourths of its length, and having a first collar about its top and a second collar situated below the threads;said threads on said segments and said drive shaft being of the same dimensions for cooperation therebetween, and said collars on said segments and said drive shaft being capable of acting as stops to prevent said segments from becoming dissociated;rotation means to rotate the drive shaft in a forward direction and in a reverse direction; anda cylindrical top cap on which the load is supported;whereby when the load is supported on said lift assembly and the rotat ion means causes the drive shaft to be rotated in the forward direction the segments rotate in the forward direction and move upward such that the lift assembly telescopes upward raising the load, and when the rotation means causes the drive shaft to be rotated in the reverse direction the segments rotate in the reverse direction and are moved downward such that the lift assembly is collapsed and the load is lowered. 31. A lift assembly as in claim 30 wherein the top cap comprises a flat top member, at least one plate bearing situated under the flat top member, and a bearing locator centrally affixed to the underside of the flat top member, whereby the bearing is rotatable with the segments and the top cap does not rotate with the segments.