Automatic adjustable spreader bar

A device for lifting oversized pieces of material. The device includes 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 and 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, and 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.

FIELD OF THE INVENTION

This invention pertains to a device for lifting large objects such as I-beams and precast slabs of concrete.

BACKGROUND OF THE INVENTION

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.

BRIEF SUMMARY OF THE INVENTION

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.

DETAILED DESCRIPTION OF THE INVENTION

The invention is directed to a device10for lifting oversized pieces of material12. As shown inFIGS. 1-3,5A, and8, the device10is comprised of a spreader bar14capable of attaching to a lifting vehicle (not shown). At least two cross members16are attached to the spreader bar14which is also connected to at least one cross-member power source18. The at least one cross-member power source18is connected to at least one drive mechanism20which in turn, is connected to at least one of the at least two cross members16. A load-pick power source22is attached to each of the at least two cross members16. The load-pick power source22is connected to at least one load-pick drive mechanism25which is also connected to each of the at least two load pick points27. The cross-member power source18and the load-pick power sources22are each electrically connected to an operating panel in a cab of the lifting vehicle.

In an embodiment of the invention, the cross-member power source18and the load-pick power source22are electric motors. These power sources18,22may also be hydraulic motors or any other type of power source known in the art. The drive mechanism20can be a chain32, as shown inFIGS. 4 and 5, however, any suitable drive mechanism known in the art including, but not limited to, a drive belt or hydraulic cylinder may be used without departing from the scope and spirit of the invention. In an embodiment, the cross-member power source18and load-pick power source22are each electrically connected to an operating panel remote from the lifting device. This embodiment allows an operator in the lifting vehicle cab or standing on the ground outside of the lifting vehicle to operate the cross members16and load-pick points27so as to correctly position them with respect to the material12to be lifted.

The load pick points27can be a self-locking hook device26, as shown inFIGS. 1-3,9(a) and (b), or a twist-lock type device, as shown inFIGS. 10-12.

In an embodiment of the invention, the cross-member power source18is connected to a first and a second drive mechanism20and each of the first and second drive mechanisms20are connected to a first and a second cross-member16, respectively. First and second load-pick power sources22are also connected to the respective first and second cross-members16. These load-pick power sources22are also connected to their respective load-pick latching mechanisms24which are also connected to a first and second load pick point27, respectively.

In an embodiment, as shown inFIGS. 7 and 8A, each one of the two load pick devices26is connected to a hydraulic actuator25, which functions as the load-pick latching mechanism24. Motion of the pick-point assemblies and the latching devices attached to the pick point assemblies may also be accomplished by other means such as electric actuators29, as shown inFIGS. 14 and 15, without departing from the scope and intent of the invention.

The spreader bar14is connected to a lifting vehicle (not shown), such as a crane, in any manner well known in the art. As shown inFIG. 5a, the spreader bar14may be attached to the crane by lift points28that can engage the crane hooks. The spreader bar14is equipped with at least two cross members16that are mechanically moveable along the length of the spreader bar14. In an embodiment, as shown inFIGS. 4 and 5, the cross members16are moved using a motor18, sprockets30, and chain system32. Other mechanical, hydraulic, or electric means, however, may be employed within the scope and context of this invention. A gear box34, may also be employed with the drive mechanism20, as shown inFIGS. 5 and 6.

The movement of the cross members16may 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 inFIG. 13, a crane power system is electrically connected to an operating panel from which the cross members16and the pick points27may be controlled. This connection may be either a wired or wireless connection.

When in operation, an operator in or remote from the cab of the lifting vehicle actuates the movement of the cross members16by positioning a switch on the operating panel so as to extend or retract a particular cross member16. Movement of this switch sends a signal that activates the cross member actuator or drive mechanism20which results in the cross member16being repositioned along the length of the spreader bar14. Once the cross members16are in position, the operator positions another switch sending a signal that activates the respective pick point's actuator. This allows the pick point27to slide along the length of the cross member16until the point is positioned in the correct location. After the pick point27is correctly positioned along the cross member16, the operator activates another switch on the control panel, thereby actuating the latching device26to engage the lifting means on the object12to be lifted. When all lifting means are properly engaged the crane operator can lift the object12in any manner known in the art. After lifting and placing the object12in 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 members16and load pick points27and latching device26can 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 points27. The load pick points27are moveable in a lateral direction perpendicular to the length of the main spreader beam14. 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 points27may be equipped with a variety of lifting devices to engage the object12to be lifted.FIG. 9(a) and (b) shows an example of one such device, a self-locking hook that is used to engage a loop-type lifting connection on an object12, whileFIGS. 10-12show a twist-lock type of device for engaging an insert in an object12to 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.