Abstract:
A load test system includes a test bed frame which extends horizontally along a first axis and includes two rolling beams moveably mounted securely in the test bed frame for being moved to desired position. The rolling beams have plural attachment locations for attaching a test lift device. A hydraulic power station is located spaced perpendicular from the test bed frame along a second axis and includes a hydraulic cylinder with a line connected to the hydraulic cylinder at one end, which is connectable to a test device at another end for applying a load when the test device is attached to the test bed. Beam members connect the hydraulic power station and the test bed frame to form a rigid structure.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is related to U.S. Provisional Patent Application Ser. No. 60/970,546 for Load Test System filed Sep. 7, 2007, the disclosure of which is specifically incorporated in its entirety by reference herein. Applicants hereby expressly claim priority to the filing date of Sep. 7, 2007 of Application Ser. No. 60/970,546. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to a system for load testing devices such as for use with “below-the-hook lifting devices.” More particularly, the invention relates to such a test system which provides a standardized methodology with recorded results which can be used to ensure compliance with regulations from relevant government agencies. 
       BACKGROUND OF THE INVENTION 
       [0003]    A “below-the-hook lifting device” is a sling, hook, magnet, or vacuum device, beam or fabricated structural device that is suspended from the hook of an overhead crane or hoisting device, and used to lift an object. They are also sometimes referred to as overhead lifting devices. Under current standards for the design and manufacture of “below-the-hook lifting devices,” mandatory load testing is not required of the manufacturer. On the other hand, regulatory agencies such as OSHA in the United States, often demand testing and the burden of such testing often falls on the user to provide certification that the lifting device has been load tested prior to use. Failure to comply with testing can result in large fines being levied on the user. 
         [0004]    Many manufactures of “below-the-hook lifting devices” (hereinafter “lifting device,” “test device” or “test lift device”) produce such lift devices in batches of several hundred in a single production run. In order to provide testing certification for end-user purchasers, the manufacturer may choose to load test random numbers of lift devices produced in a single production run. This practice does not guarantee that all produced lift devices satisfy the regulatory standards, and it is preferable that every lift device produced be load tested before delivery to a customer. Unfortunately, such a task has to date been prohibitably expensive. 
         [0005]    For the above reasons, what is needed is a load test system which can be used by a manufacturer to test every lift device produced in a cost effective way, and with the ability to provide accurate certification to an end-user purchaser that the lift device purchased has been tested and satisfies regulatory standards. 
       SUMMARY OF THE INVENTION 
       [0006]    The invention is a load test system for lift devices which includes a test bed frame. The test bed frame extends horizontally along a first axis. Two rolling beams are movably mounted securely in the test bed frame for being moved to desired positions along the first axis within the test bed frame and, in a specific aspect, the rolling beams can be locked into position therein. The rolling beams include plural attachment locations for attaching a test lift device thereto. A hydraulic power station is spaced from the test bed frame along a second axis perpendicular to the first axis. The hydraulic power station includes a connecting line connected to a hydraulic cylinder in the power station at one end, and connectable to a test lift device at another end for applying a load to the test lift device when the test lift device is attached to the test bed frame and to the hydraulic power stations hydraulic cylinder. Beam members serve to connect the hydraulic power station and the test bed frame to form a rigid structure. 
         [0007]    In a specific aspect, the rigid structure is arranged to have the connecting line extend horizontally, and includes a winch and slack take up cable associated with the connecting line for taking up any slack in the connecting line when connected to a test lift device to be tested resulting from gravitational pull toward the floor of the rigid structure. 
         [0008]    Embodiments include at least one load sensor associated with the hydraulic cylinder for measuring a load applied to the test lift device. At least one camera may be provided for visually recording a load test conducted on the test lift device. 
         [0009]    A hardened monitoring and control station may also be provided separate from the rigid structure, and may be enclosed and hardened to protect a user conducting the test in the event of catastrophic failure and debris resulting from failure of a test lift device during a test. Recording devices and display devices may also be located in the monitoring and control station to record data picked up by the load sensors resulting from the test, as well as to visually record the test through use of the camera, and to display the data and images. 
         [0010]    These and other advantages and features that characterize the invention are set forth in the claims annexed hereto and forming a further part hereof. However, for a better understanding of the invention, and of the advantages and objectives attained through its use, reference should be made to the Drawings, and to the accompanying descriptive matter, in which there are described exemplary embodiments of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  shows in perspective view a load test system in accordance with the invention with some components removed for the sake of clarity. 
           [0012]      FIG. 2  is a partial view of a rolling beam viewed from the front as mounted on the test bed frame. 
           [0013]      FIG. 3  is a partial view of a rolling beam viewed from the rear as mounted on the test bed frame. 
           [0014]      FIG. 4  is a top plan view of the load test system rigid structure. 
           [0015]      FIG. 5  is a side view of the load test system rigid structure. 
           [0016]      FIG. 6  is a perspective view of the hydraulic power station. 
           [0017]      FIG. 7  is a side view in partial cross section of the hydraulic power station. 
           [0018]      FIG. 8  is a view in disassembled form of a portion of the hydraulic power station. 
           [0019]      FIG. 9  is a partial perspective view of the load test system shown testing a forklift spreader. 
           [0020]      FIG. 10  is a partial perspective view of the load test system shown testing a straight piece of chain. 
           [0021]      FIG. 11  is a partial perspective view of the load test system shown testing a telescopic spreader. 
           [0022]      FIG. 12  is a partial perspective view of the load test system, shown with a mesh wire assembled thereon. 
           [0023]      FIG. 13  is a perspective view of the circled portion of  FIG. 12 , showing how the wire mesh slides open and closed, and is attached to the rigid structure. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    In one respect, embodiments consistent with the invention may capitalize on a load test system that can test a wide variety of shapes and sizes, based in part upon a rolling beam feature, and the size of the load test system which provides numerous anchoring locations so that the test lift device can be properly evaluated and tested under conditions substantially approximating actual field conditions. 
         [0025]      FIG. 1  illustrates in perspective view a load test system  11  in accordance with the invention, with some of the components thereof not shown for the sake of clarity. A test bed frame  13  extends horizontally along a first axis and includes rolling beams  15  which typically have a number of connection points spaced equally along the vertical axis of the beams  15  for attachment of pad eyes  17 . The beams  15  can roll back and forth along the test bed frame  13  as more clearly shown in  FIGS. 2 and 3  through the means of rollers  101 . Securing tabs  19  on the rear side of the test bed frame  13  serve to secure the rolling beams  15  on the test bed frame  13  when undergoing a load test and resulting in forces applied in the direction of the arrow  18  shown in  FIGS. 2 and 3 . Optionally, rolling beams  15  can be locked in place to prevent further horizontal movement. 
         [0026]    A hydraulic power station  41  is provided along an axis perpendicular to the test bed frame  13  and includes a hydraulic ram or cylinder with a connecting line as shown and described hereafter, for applying a load on a test lift device secured to the test bed frame  13 , for example, at the pad eyes  17 . 
         [0027]    The hydraulic power station  41  also includes a winch arrangement, as described hereafter, for taking up slack on a horizontally extending connecting line connected to a test lift device. The winch arrangement is powered by hydraulic fluid passing through hydraulic winch lines  49  and  51 . Hydraulic fluid is also passed through hydraulic pull and push lines  43  and  45  for powering the hydraulic ram/cylinder. The pressurized hydraulic fluid is provided by hydraulic pumping unit  47  shown separate from the hydraulic power station  41 . 
         [0028]    Optionally, a hydraulic pressure meter (not shown) can be connected to the lines  43  and  45  and housed in the monitoring and control station. The reading of the pressure from the meter can serve as an indirect indicator of a load placed on a test lift device. 
         [0029]    As may be appreciated, the hydraulic power station  41  may also include a load cell connected to the hydraulic ram to transmit data through wire  55  to a load cell read out  57 . One or more cameras  53  may also be positioned for recording a test and may be connected to a display device  59  within a monitoring and control station, which is separate and distinct from the location where the tests are conducted. 
         [0030]    The hydraulic power station  41  is connected to the test bed frame  13  through means of upper beam members  21  and lower beam members  31 . The lower beam members  31  are preferably recessed (such as in a floor) to allow test lift devices to be passed into the rigid structure, which is made up of the connection of the test bed frame  13  beam members  21  and  31  and hydraulic power station  41 . 
         [0031]    With respect to the monitoring and control station, although not shown in an enclosed area, the monitoring and control station is an optionally separate room with a harden enclosure (not shown) to protect the operator against catastrophic failure and debris resulting from such failure when a load test is conducted on a test lift device. A display and load cell read out may be connected to recording devices as part of operating control box  61  to provide a permanent visual record and read out of a load applied during a test, and the operation of the test lift device in response to such load during the test being conducted. 
         [0032]    For ease of further understanding, it is noted that  FIGS. 4 and 5  illustrate in top-plan view and side view of the rigid structure of the load test system  11  of the invention. 
         [0033]    The hydraulic ram or cylinder arrangement of the hydraulic power station  41  is shown in greater detail in  FIGS. 6-7 . As shown in  FIGS. 6-7 , a pulley  105  with a winch  107  arrangement can be connected to the connecting line  106  for the test lift device to pull on the connecting line  106 . The connecting line  106  may be a chain in one exemplary embodiment. Slack in the connecting line  106  is optionally taken up by pulling the connecting line along line X (shown in  FIG. 6 ) to bring it into a taught horizontally extending state upon actuation of hydraulic ram  103 . The ram  103  includes a hydraulic cylinder, and no movement is wasted by taking up slack along direction X. As will be more readily appreciated, the hydraulic power station with the hydraulic ram  103  can also pivot about a pivot point along the arrow Y as shown in  FIG. 6 , depending on the lift device being tested. 
         [0034]    The components making up the hydraulic ram  103  are further shown in  FIG. 8  and include an outside cylinder assembly  201  which fits over an inside cylinder assembly  211 . The outside cylinder assembly includes a cable pulley  205  assembled on a cable pulley assembly  203  through pin  207 . A load cell  55  is located on the inside cylinder assembly in association with hydraulic cylinder  213 , which when actuated through hydraulic fluid pressure, moves rearwardly along the direction of arrow X of  FIG. 6  towards a cylinder endplate  215  and backstop block  217 . 
         [0035]      FIGS. 9-11  illustrate various tests being conducted with the load test system  11  of the invention. In the case of  FIG. 9 , a forklift spreader  301  is attached to the rolling beams  15  at the pads  17 , and with the rolling beams  15  being placed at selected locations. The connecting line  106 , preferably a cable, is connected to the forklift spreader  301 . A load is applied along the direction of the arrow shown in association with the connecting line  106 . 
         [0036]      FIG. 10  illustrates a load test system  11  conducting a test on a chain  305  which replaces connecting line  106 . The chain  305  is put under stress by attachment to a central support beam at an anchor point  303  having a clevis adaptor. In the case of  FIGS. 9 and 10  as well as  FIG. 11 , the top structure, i.e., beam members  21 , of the test load system has been removed for clarity of understanding. 
         [0037]      FIG. 11  illustrates a load test on a telescopic spreader  307 . Shackles connect the spreader  307  to the rolling beams  15  of the test bed frame  13 . Cables  309  connect the spreader to the connecting line  106 . 
         [0038]      FIGS. 12 and 13 , respectively, illustrate in perspective view a barrier mesh  401  which can be attached around the load test system  11  to prevent debris resulting from a test failure from flying out of the rigid structure. The mesh  401  can be arranged in two substantially parallel layers as an inner and outer layer of mesh. The mesh  401  is slideably mounted in connection with the beam members  21  and  31  so as to allow an opening  403  resulting from sliding motion. Once the mesh  401  is closed, it can be secured through attachment holes  405  to provide a more rigid structure and protection for those around the load test system  11 . 
         [0039]    It will be appreciated that test load capabilities for the system can be engineered in a conventional manner. For example, a system capable of applying a load of 750,000 lb may be engineered for use with loads of up to 600,000 lb. for periods of about 3 to about 5 minutes on a test lift device. The extra capacity provides a margin of safety. Further, as will be appreciated, through the use of appropriate jig arrangements, such test loads can be effectively multiplied by factors of 3 to 5 times the design tolerances. 
         [0040]    While the present invention has been illustrated by a description of various embodiments and while these embodiments have been described in considerable detail, it is not the intention of the Applicants to restrict, or any way limit the scope of the appended claims to such detail. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method, an illustrative example shown and described. According, departures may be made from such details without departing from the spirit or scope of Applicants&#39; general inventive concept.