Patent Application
20050236352
1. Field of Invention
The present invention relates generally to a portable crane for lifting objects. More specifically, the present invention relates to a portable crane for lifting heavy objects to the rooftop.
2. Description of Related Art
Heavy objects, such as air conditioner units and ventilation systems, often have to be lifted to the rooftop of a building for installation. If the object is small enough, it may be brought up to the rooftop through the stair well or the elevator, if available. However, more often than not, the object is either too heavy or too large to be brought up to the rooftop through the stair well or the elevator. The heavy and/or large object often has to be brought up to the rooftop from the outside of the building by lifting it directly from the ground to the rooftop.
A fixed and dedicated crane such as those used for lifting the platforms for washing windows on a large office building may be used if they are available. However, these cranes are fixed to the building as a permanent fixture and are relatively expensive. Furthermore, these fixed cranes are not practical or economical for small buildings and for single use applications such as for lifting an air conditioner unit up to the rooftop for installation.
Conventional means to lift a large and/or heavy object up to the rooftop without a fixed and dedicated crane are limited. One method is to have several people manually pull the object to the roof top. The people pulling the object will pull on a rope while standing on the rooftop to lift the object to the rooftop. This manual method requires sufficient manpower to not only lift the object but to also hold the object in mid-air when one or more person is tired or accidentally releases their grip on the rope. This method also risks damaging the side of the building if the object is dragged on or makes contact with the side of the building. Obviously this manual method risks not only damaging the object being lifted and the building but also the safety of the persons lifting the object.
The other method is to use a movable hydraulic platform that has sufficient height to raise the object to the rooftop. Obviously, this method is much safer and easier than the manual method. However, this method requires the use of an expensive movable hydraulic platform that must be delivered to the work site for use and removed from the worksite after use. Furthermore, the moveable hydraulic platform has a limited height that they can reach. This method is not feasible if the building is taller than the height of the moveable hydraulic platform when fully raised.
Yet another conventional method is to use a crane positioned on the ground adjacent to the building with sufficient reach to reach up and onto the rooftop to lift and place the object onto the rooftop. This method requires mobilization of an extremely large crane and large amount of access. This method also requires extensive setup and operation, and is expensive.
Therefore, a safe, economical, and easily portable device that can be setup and removed easily from the rooftop to lift heavy objects to the rooftop is desired and lacking.
The present invention is a portable crane that can be easily set up on the rooftop. The portable crane can be used to safely and easily lift objects to the rooftop. The portable crane comprises of a support structure that will support the portable crane near the edge of a rooftop with a boom pivotally connected to a support column affixed to the support structure and a cable extending between the free end of the boom to lift the load and a means to pull the cable such as a winch. The support structure will stabilize and support the portable crane and the load it is lifting on the edge of a rooftop. The portable crane can be quickly set up on top of the roof and safely lift a load to the top of the roof. The portable crane can be easily moved from one rooftop to another rooftop.
The portable crane comprises of a support structure that will support the portable crane near the edge of a rooftop with a boom pivotally connected to a support column affixed to the support structure and a cable extending between the free end of the boom to lift the load and a means to pull the cable. The support structure will stabilize and support the portable crane and the load it is lifting on the edge of a rooftop. The portable crane can be quickly setup on top of the roof to safely lift a load to the top of the roof and can be easily moved from one rooftop to another rooftop.
The two pairs of the connecting members 17, 18, 19, 20 with the adjustable locking member 21 may also be positioned such that one connecting member in each pair of connecting members is positioned parallel to the other corresponding connecting member in the other pair while the other connecting member that is pivotally connected to the first connecting member is positioned such that it converges with the other corresponding connecting member from the pivot connection to a base member with a stabilizing member 22 connecting the two pairs together at the pivot connection between the two connecting members as shown in
Although the description above contains many specificities, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. Thus the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given.
