Patent Application
20060156687
Not Applicable.
Not Applicable.
Not Applicable.
1. Technical Field
This invention relates to elevating apparatuses and, more particularly, to a portable lift assembly for lifting construction materials at a job site.
2. Prior Art
It is frequently necessary to lift workers or materials, particularly drywall, from the ground to an elevated position on construction sites, or to provide a safe work platform at desired elevation for various operations such as tightening of bolts or painting. Various lifting or elevating apparatuses have been developed and used. One common problem with the known arrangements is that the work platform, as it is lifted to an elevated position, is unstable and liable to swing due to winds, making the workers feel insecure and preventing them from doing desired works.
The work platform can be supported stably against unwanted wobbling movements by a rugged and heavy mechanism for lifting the platform or an additional mechanism for reinforcing the platform. However, these mechanisms are complex in construction, result in an additional cost, and cannot be transported easily. There is known a manual support arrangement in which a plurality of ropes are attached to an elongated ladder-like mechanism supporting thereon a work platform and manually pulled in opposite directions to render the platform stable against wobbling motions. Although the ladder-like platform supporting mechanism is relatively lightweight and thin in construction, several workers are required just for pulling and gripping the ropes. As a result, the known manual support apparatus has failed to find widespread general use.
Accordingly, a need remains for a lift assembly that can be easily transported to a job site and provides a stable platform for elevating materials. The present invention satisfies such a need by providing a portable lift assembly that allows a worker to raise, and then hold in place, drywall and other building materials. Such an invention would be especially helpful to drywall contractors because it would enable one person to install the drywall, saving a substantial amount of time and expense.
In view of the foregoing background, it is therefore an object of the present invention to provide an apparatus for lifting construction materials. These and other objects, features, and advantages of the invention are provided by a portable lift assembly for assisting an operator to elevate drywall paneling towards a ceiling during installation procedures.
The lift assembly includes a rigid outer frame including a plurality of integrally mated support members configured to define a generally rectangular shape. The support members have substantially linear shapes and are formed from tubular steel. A rigid inner frame including a plurality of integrally mated support members and having an outer perimeter is spaced inwardly from an inner perimeter of the outer frame. The inner frame is telescopically positioned within the inner perimeter of the outer frame and along a substantially vertical plane such that the inner frame can be selectively biased between raised and lowered positions while the outer frame remains at a fixed ground position.
The assembly includes a mechanism for selectively elevating the inner frame along a vertical plane wherein the inner frame remains spaced inwardly from the outer frame such that the inner frame can be slidably guided along the vertical plane without directly contacting the outer frame. The assembly further includes a mechanism for supporting at least one drywall panel on top of the inner frame wherein the drywall panel can be effectively elevated between alternate heights during operating conditions while the operator's hands remain freely disengaged from the drywall panel.
Selected ones of the inner frame support members and selected ones of the outer frame support members are vertically oriented substantially parallel to the vertical plane and symmetrically spaced at opposing corners of the outer and inner frames respectively. Other ones of the support members are horizontally oriented and medially secured to the selected support members such that the other support members become vertically aligned along a longitudinal length of the selected inner frame and outer frame support members respectively.
The elevating mechanism preferably includes a manually-operable jack including a rotatable winch and oppositely positioned base and top surfaces. The base surface may be medially positioned on corresponding ones of the outer frame support members. The top surface may be medially engaged beneath corresponding ones of the inner frame support members such that opposing lift forces will cause the inner frame to be elevated when the operator adapts the jack between retracted and extended positions.
The elevating mechanism further preferably includes at least one rigid guide bracket having a linear central portion and an integrally coupled arcuate end portion slidably engageable with the inner frame. The guide bracket may further have an opposite end portion mated with the outer frame such that the guide bracket may be maintained at a static position while the inner frame is elevated toward the ceiling.
The drywall panel supporting mechanism preferably includes a substantially rectangular platform sized and shaped for being positioned on an upper end portion of the inner frame. The platform preferably has a substantially planar top surface oriented along the horizontal plane such that the drywall panel may be effectively maintained at equilibrium during transit.
A plurality of U-shaped brackets preferably are positioned about the inner frame and spaced along opposite sides thereof such that the brackets become situated subjacent the platform. Each U-shaped bracket preferably includes outwardly extending flange portions for threadably receiving fasteners therethrough such that the platform and the inner frame become securely coupled.
The outer frame further preferably includes a plurality of elongated rails connected thereto wherein selected ones of the rails are perpendicularly oriented along traversing planes and vertically aligned along the selected outer frame support members for providing additional stability during operating conditions.
The novel features believed to be characteristic of this invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings in which:
The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which a preferred embodiment of the invention is shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiment set forth herein. Rather, this embodiment is provided so that this application will be thorough and complete, and will fully convey the true scope of the invention to those skilled in the art. Like numbers refer to like elements throughout the figures.
The apparatus of this invention is referred to generally in
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The inner frame 30 is telescopically positioned within the inner perimeter of the outer frame 20 and along a substantially vertical plane such that the inner frame 30 can be selectively biased between raised and lowered positions while the outer frame 20 remains at a fixed ground position. The outer frame 20 and inner frame 30 resemble conventional scaffolding commonly used in the construction industry, and operate on the same principle.
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The outer frame 20 further preferably includes a plurality of elongated rails 22 connected thereto wherein selected ones of the rails 22 are perpendicularly oriented along traversing planes and vertically aligned along the selected outer frame support members 21 for providing additional stability during operating conditions.
The lift assembly 10 provides a safe and easy method of raising drywall to a desired height and then holding it there while it is being secured to ceiling joists or wall studs. Such a lift assembly is light weight, reasonably priced, and offers an attractive cost saving alternative to renting a wheeled, gas-powered lift platform. The lift assembly 10 increases the level of safety on a job because workers would be less likely to attempt to lift and maneuver drywall panels themselves.
While the invention has been described with respect to a certain specific embodiment, it will be appreciated that many modifications and changes may be made by those skilled in the art without departing from the spirit of the invention. It is intended, therefore, by the appended claims to cover all such modifications and changes as fall within the true spirit and scope of the invention.
In particular, with respect to the above description, it is to be realized that the optimum dimensional relationships for the parts of the present invention may include variations in size, materials, shape, form, function and manner of operation. The assembly and use of the present invention are deemed readily apparent and obvious to one skilled in the art.
