Abstract:
A counterbalanced lifting beam designed to lift and permit balancing of heavy loads. The lifting beam includes an internal counterweight that is adapted to be hydraulically adjusted by use of a manually operated control mechanism. The lifting beam also includes a rigid elongated lifting tower to add stability to the lifting beam and includes a centralized storage cabinet, which stores control mechanism and increases the weight concentration and the overall stability of the beam. Storage batteries and hydraulic control equipment are fully encased in the storage cabinet. As the lifting beam is held by the crane cable and a swivel, the beam can be moved in three dimensions.

Description:
BACKGROUND 
   This invention is designed to provide an apparatus to be used primarily in conjunction with a crane in situations requiring a load, be it materials, equipment or otherwise, to be inserted into a portal or under an obstruction by the use of an elongated boom. Oftentimes, during construction, it is necessary to place materials in elevated locations without the aid of an attached loading platform. This necessitates the use of hooks and ropes to position the load and manually pull it through an opening, usually a vacant window opening. This function can be dangerous to both the employees and to the load, especially when the task is at great heights. Prior art lifting beams, as shown in U.S. Pat. No. 6,048,012, utilizing a counterweight to offset the weight of the load require continuous counterweight adjustment, during load transfer, in order to prevent unwanted shifting of the load. 
   In view of the above, it should be appreciated that there is a need for a lifting beam that permits loads of various weights to be transferred from a ground level to an elevated level and through an opening in a building without the requirement of undue counterweight adjustment while the transfer is occurring. The present disclosure satisfies these and other needs and provides further related advantages. 
   SUMMARY 
   The present invention is directed to a counterbalanced lifting beam having a centralized weight concentration that is designed to lift and permit balancing of heavy loads. The lifting beam includes an internal counterweight that is adapted to be hydraulically adjusted by use of a manually operated control mechanism. The lifting beam also includes a rigid elongated lifting tower that increases the stability of the lifting beam and includes a centralized storage cabinet, which stores control mechanism and increases the weight concentration and promotes the overall stability of the beam. Storage batteries and hydraulic control equipment are fully encased in the storage cabinet. As the lifting beam is held by the crane cable and a swivel, the beam can be moved in three dimensions. 
   Other features and advantages of the disclosure will be set forth in part in the description which follows and the accompanying drawings, wherein the embodiments of the disclosure are described and shown, and in part will become apparent upon examination of the following detailed description taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of the preferred embodiment of the lifting beam attached to a crane; 
       FIG. 2  is a perspective view in phantom of the lifting beam of  FIG. 1 , illustrating the relative relationship between the internal components of the lifting beam, particularly the hydraulic cylinder and the internal counterweight; 
       FIG. 2   a  is a cross sectional view of the lifting beam of  FIG. 1  taken along lines  2   a – 2   a  in  FIG. 2 ; 
       FIG. 3  is a perspective view in phantom illustrating the centralized storage cabinet; and 
       FIG. 4  is a top view of the control cable unit. 
   

   DETAILED DESCRIPTION 
   As illustrated in the drawings, the present invention relates to a lifting beam  10  which is adapted to be connected to a crane  13  and is designed to permit an operator to quickly level the beam  10  after a load  15  has been secured thereto as shown in  FIG. 1 . The use of the lifting beam  10  permits quick and easy transportation of a load from the ground to a location elevated from the surface below. The lifting beam, generally designated with the numeral  10 , includes a housing member  12 , a load securing member  14 , a rigid elongated lifting tower  16 , a hydraulic system, a centralized storage cabinet  19  and a counterweight  20 . The lifting beam  10  is designed to be connected to a crane cable  22  of the crane  13 . 
   The housing member  12 , as shown in  FIG. 2 , includes a heavy gauge steel housing welded to form a tube. The housing member  12  includes a first end  24  adapted to receive the load  15  and a second end  26  that permits extension of the counterweight  20 . The lifting tower  16  is rigidly secured to the housing member  12  along its center of gravity and provides for an eyelet  28  at the top end  30  of the lifting tower  16 . The lifting tower  16  is preferably welded to the housing member  12  but other securing means may also be employed including bolting or riveting. 
   The lifting tower  16  includes a forward surface  32  that acts as a stop to prevent the lifting beam  10  from being inserted too far into the building, preventing damage to the crane cable  22 . The forward surface  32  includes a pad  34  that acts as a cushion in the event the lifting tower  16  contacts the building structure, to prevent marring of the building&#39;s facade. The lifting tower  16  is rigidly secured to the housing member  12  to increase the stability of the lifting beam  10  and is designed to provide a pocket  36  to permit placement of the centralized storage cabinet  19 . The lifting tower  16  is comprised of first and second side plates  38 ,  40  that are connected to sides  42  of the housing member  12 . The lifting tower  16  includes a bridge plate  44  that interconnects the first and second side plates  38 ,  40  to form an I-beam arrangement and includes a first end  46  and a spaced apart second end  48  as shown in  FIG. 3 . The first end  46  of the bridge plate  44  is connected to a top surface  50  of the housing member  12  and includes an opening  52  therein to permit the passage of a hydraulic cylinder  54 . The second end  48  of the bridge plate  44  is connected to the eyelet  28 . 
   The eyelet  28  is adapted to be connected to a hook  21  on the crane cable  22 , as shown in  FIG. 2 . Since the eyelet  28  is spaced a considerable distance from the housing member  12 , the stability of the lifting beam  10  is increased by increasing the moment force that needs to be applied to the lifting beam  10  in order to offset the balance of the beam. Enhanced stability is also due to the I-beam design of the lifting tower  16 . Stability is further increased because of the lifting beams attachment to the top surface  50  and sides  42  of the housing member  12 . The use of the lifting tower  16  eliminates the need for an automatic balancing system that would constantly adjust the counterweight  20  to prevent undesirable tipping of the load. Once the lifting beam  10  is initially balanced by the operator, there is no longer a need for continuous counterweight adjustment while the beam is being elevated from the ground. 
   The use of the lifting tower  16  also permits the housing member  12  of the lifting beam  10  to be inserted further into the building structure, exceeding the range of a lifting beam in combination with a triangular harness and hook arrangement as illustrated in U.S. Pat. No. 6,048,012. Use of the triangular harness limits insertion of the housing member  12  into the building. 
   The load securing member  14 , shown in the preferred embodiment as a swivel hook  21 , is attached to the first end  24  of the housing member  12 , as shown in  FIG. 2 . A chamber  56  is defined within the housing member  12  and extends the length of the housing member  12 . The counterweight  20 , which is connected to the hydraulic cylinder  54 , is slidably disposed within the chamber  56  and adapted to move axially in response to the change in the angular orientation of the housing member  12 , as controlled by the operator. The counterweight  20  can partially extend outside the second end  26  of the housing member  12  to a distance to sufficiently balance the load attached to the first end  24  of the housing member  12 . 
   The preferred method of use of the lifting beam  10  involves a cooperative effort between the crane operator and the lifting beam operator. The eyelet  28  of the lifting tower  16  of the lifting beam  10 , is attached to the crane  13  by means of a swivel hook, that is placed through the eyelet  28 . After the housing member  12  has been initially lifted off of the ground, the lifting beam operator removes the control cable unit  58 , as seen in  FIG. 2 , from a central cable stowage box  60  and directs the crane operator to position the housing member  12  over the load  15 . It is known that the load  15  can be attached to the housing member  12  in one of two ways. The preferred method, is to have the load  15  strapped or secured by a suitable means to the load securing member  14  at the first end  24  of the housing member  12 . 
   The alternative method is to wrap a sling or other strapping material around the housing member  12 , also at the first end  24  of the housing member  12 , and utilize a set of guide loops  64  positioned along the sides  42  of the housing member  12 , as shown in  FIG. 2 , to insure the load securing straps remain in place and do not slide off of the housing member  12 . The advantage of using the load securing member  14  to attach the load  15  to the first end  24  of the housing member  12  is that the load  15  can be rotated in the horizontal plane while the strapping wrapped around the housing member  12  is fixed with only minimal movement in the horizontal plane. 
   Once the lifting beam  10  is attached to the crane and the load  15  is attached to the housing member  12 , the crane picks up the lifting beam  10  by slowly raising the crane cable  22 . Initially, as the lifting beam  10  is slowly raised, the housing member  12  will not be horizontally oriented due to the load  15  at the first end  24  of the housing member  12 . To level the housing member  12 , the operator depresses the extend button  74  on the control cable unit  58 , which energizes the hydraulic system, extending the hydraulic cylinder  54  and extending the counterweight  20  from the second end  26  of the housing member  12 . Movement of the counterweight  20  in a direction opposite the load balances the overall weight of the beam and load at the fulcrum, returning the housing member  12  to a horizontal position. Due to the increased stability caused by the rigidly attached lifting tower  16  continual adjustments of the counterweight  20  are not required. The operator, with use of the cable unit  58  has the ability to reposition the load  15  to compensate for wind load and to raise or lower the load  15  for entry through an opening in a building structure. 
   The hydraulic system used to extend and retract the hydraulic cylinder  54  includes a hydraulic pump  66 , a reservoir  68  for storing hydraulic fluid, electric power supply  70 , solenoid valve  67  and the hydraulic cylinder  54 , best illustrated in  FIG. 3 . Although a hydraulic system is shown, it is known that other similar type of arrangements for axially moving large masses can also be used, including, but not limited to, a rotary screw assembly, rack and pinion and other devices well known to those skilled in the art. The hydraulic pump  66  and the reservoir  68  are positioned adjacent to the lifting tower  16  within the storage cabinet  19 . 
   In response to an unbalanced load, the control cable unit  58  is used by the operator to activate the hydraulic system. The power source for the hydraulic system consists of batteries  70  with an on-board charger  72 . A gasoline engine also may also be used. The storage batteries  70  and the charger  72  are positioned within the storage cabinet  19 , adjacent to the lifting tower  16  to center the load on the beam. The positioning of the batteries  70 , charger  72  and pump  66  in the storage cabinet  19  adjacent to the lifting tower  16  concentrates the weight of the lifting beam  10  near the center adding stability eliminating the need for constant adjustment of the counterweight  20 . 
   The storage cabinet  19  is positioned upon the housing member  12  and adjacent to the lifting tower  16 . The storage cabinet  19  includes a hinge  78  that permits the storage cabinet  19  to be tilted to an open position to access the batteries,  70 , charger  72 , or hydraulic pump  66  within the cabinet  19 . The oil reservoir  68  is located inside of the lifting tower  16  to further concentrate the load at the center of gravity of the beam. The storage cabinet  19  includes shelving units  80  that permit vertical stacking of the various accessories to further concentrate the equipment load adjacent to the lifting tower  16 . The storage cabinet  19  also permits the storage of the hydraulic directional valve, the electrical disconnect and additional storage for tools and rigging. 
   The beam operator uses the control cable unit  58  to initially level the housing member  12  by pressing the extend button  74 , as shown in  FIG. 4  which electrically activates the internal motor of the hydraulic pump  66 , which in turn axially displaces the hydraulic cylinder  54 . The counterweight  20 , which is connected to the hydraulic cylinder  54 , is equally displaced axially away from the first end  24  of the housing member  12  until the housing member  12  is once again horizontally level. 
   With the load  15  attached to the first end  24  of the housing member  12 , the housing member  12  and attached load  15  is further lifted by the crane operator to eventually be delivered to the desired location. To ease in the axial displacement of the counterweight  20 , a series of rollers or wear pads  77  are provided along the inner walls of the housing member  12 , to enable the counterweight  20  to move easily and not to impinge on the sides, top or bottom of the housing member  12 , as shown in  FIG. 2 . 
   Once the housing member  12  and attached load  15  reaches the desired location, the first end  24  of the housing member  12  with the attached load  15  are inserted through an opening in a building to place the load  15  on a desired floor. Once the load is inserted through the opening in the building, the beam operator removes the control cable unit  58  and pushes the retract button  76 , thereby axially displacing the counterweight  20  towards the first end  24  of the housing member  12  until there is sufficient slack in the securing device to release the load securing member  14  from the load  15 . 
   Use of the cable unit  58  to control the lifting beam  10  relieves the responsibility of the crane operator, who is “blind” as to the final positioning of the load  15 , to make any adjustments in the vertical direction. After the load  15  is disconnected from the first end  24  of the housing member  12 , the beam operator utilizes the control cable unit  58  to manually raise the first end  24  until the housing member  12  has sufficient clearance to be safely removed. The beam operator then places the control cable unit  58  in the control cable storage box  60 , and the crane operator backs out the housing member  12  from the opening in the building. 
   Removal of a load would be done in the opposite sequence as that shown and described for delivery of a load. 
   The lifting beam  10  can be designed for a wide range of loads and is sized to have the capability to balance loads attached to the beam. The lifting beam  10  saves substantial manpower, as only one operator is needed at both ends of the loading procedure, instead of multiple workers. In addition, there are increased safety effects of not having workers with pole hooks trying to physically pull the load  15  into the opening or under the structure. Finally, due to the balance of the lifting beam  10  caused by the rigid lifting tower  16  and concentrated load storage cabinet  19 , constant adjustment of the counterweight  20  is not required during load transfer. 
   Various features of the invention have been particularly shown and described in connection with the illustrated embodiment of the invention. However, it must be understood that these particular arrangements merely illustrate, and that the invention is to be given its fullest interpretation within the terms of the appended claims.