Patent Application
20070262599
This invention pertains to a device for lifting large objects such as I-beams and precast slabs of concrete.
Precast and prestressed concrete products come in many forms. These products include precast rooms such as jail cells and road and building products such as I-beams, double tees, and bridge segments.
In the normal course of a manufacturing or construction process, these precast and prestressed products must be moved several times. At a minimum, the products are moved from the mold to storage area for curing and then from storage to a transportation vehicle for shipping.
These precast and prestressed products usually have a lifting means integrally placed on them. These lifting means can be wire rope loops, inserts for attaching lifting devices, or other lifting means. The actual lifting and moving of the product is typically accomplished by the use of some type of lifting vehicle such as a gantry crane or boom crane.
The products to be lifted usually have multiple lift points and the lifting vehicle often uses a spreader bar with multiple lift points to connect to the product to be lifted. The spreader bar also has crane lift points that are used to connect the spreader bar to the lifting vehicle.
The actual connection of the product to be lifted to the spreader bar is accomplished with a variety of devices such as slings, hooks, shackles, specialized attaching devices, etc. The connections are typically made by yard personnel manually connecting the spreader lifting devices to the pick points on the product. This process often involves manually positioning variable position lifting points on the spreader. This manual process is time consuming and sometimes hazardous when yard personnel must climb on stacks of stored products to make the connections. Given these problems, an automatic and remotely controlled device that alleviates and eliminates the steps and problems previously mentioned would be an important improvement in the art.
The invention involves a device or system for lifting oversized pieces of material. The system is comprised of a spreader bar capable of attaching to a lifting vehicle. At least two cross members are attached to the spreader bar along with at least one cross-member power source. The at least one cross-member power source is connected to at least one drive mechanism which in turn is connected to at least one of the at least two cross members. A load-pick power source is attached to each of the at least two cross members as well as to at least one load-pick drive mechanism. The at least one load-pick drive mechanism is connected to each of the at least two load pick points. The cross-member and the load-pick power sources are each electrically connected to an operating or control panel in a cab of the lifting vehicle.
a is a schematic view showing the main spreader beam with a power source for moving two cross members lengthwise along the main beam.
The invention is directed to a device 10 for lifting oversized pieces of material 12. As shown in
In an embodiment of the invention, the cross-member power source 18 and the load-pick power source 22 are electric motors. These power sources 18, 22 may also be hydraulic motors or any other type of power source known in the art. The drive mechanism 20 can be a chain 32, as shown in
The load pick points 27 can be a self-locking hook device 26, as shown in
In an embodiment of the invention, the cross-member power source 18 is connected to a first and a second drive mechanism 20 and each of the first and second drive mechanisms 20 are connected to a first and a second cross-member 16, respectively. First and second load-pick power sources 22 are also connected to the respective first and second cross-members 16. These load-pick power sources 22 are also connected to their respective load-pick latching mechanisms 24 which are also connected to a first and second load pick point 27, respectively.
In an embodiment, each one of the two load pick devices 26 is connected to a hydraulic actuator 24, as shown in
The spreader bar 14 is connected to a lifting vehicle (not shown), such as a crane, in any manner well known in the art. As shown in
The movement of the cross members 16 may be controlled in unison or individually by a crane operator within the cab of the crane through the use of an individual drive system. As shown in
When in operation, an operator in or remote from the cab of the lifting vehicle actuates the movement of the cross members 16 by positioning a switch on the operating panel so as to extend or retract a particular cross member 16. Movement of this switch sends a signal that activates the cross member actuator or drive mechanism 20 which results in the cross member 16 being repositioned along the length of the spreader bar 14. Once the cross members 16 are in position, the operator positions another switch sending a signal that activates the respective pick point's actuator. This allows the pick point 27 to slide along the length of the cross member 16 until the point is positioned in the correct location. After the pick point 27 is correctly positioned along the cross member 16, the operator activates another switch on the control panel, thereby actuating the latching device 26 to engage the lifting means on the object 12 to be lifted. When all lifting means are properly engaged the crane operator can lift the object 12 in any manner known in the art. After lifting and placing the object 12 in the desired location the operator may activate the proper switch on the control panel to disengage the latch device from the lifting means.
The lifting device of the instant invention can be used with large heavy objects such as precast pieces of concrete, structural I-beams, or any other like objects. As mentioned above, control of the cross members 16 and load pick points 27 and latching device 26 can be accomplished by an operator within the cab of the lifting vehicle or by someone on the ground outside of the vehicle.
Each cross member has at least two moveable load pick points 27. The load pick points 27 are moveable in a lateral direction perpendicular to the length of the main spreader beam 14. The moving means in this case is a motor, sprocket, and chain system. However, other mechanical, hydraulic, or electric means may be employed within the scope and context of this invention.
The moveable load pick points 27 may be equipped with a variety of lifting devices to engage the object 12 to be lifted.
The foregoing discussion shows a system that can accommodate a wide variety of product lift points and lift point positions by controllable means which eliminates the necessity of having personnel making manual connections to the products to be lifted and also eliminates the necessity of having personnel climb on stacks of stored products to make connections.
All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. It should be understood that the illustrated embodiments are exemplary only, and should not be taken as limiting the scope of the invention.
