Abstract:
The present invention is directed at a bin lifting and weighing assembly comprising a bin lifting mechanism having means for engaging and lifting a bin; means for mounting the bin lifting mechanism against a structure; a load cell, mounted against the structure; for measuring a weight of the bins; wherein the means for mounting the bin lifting mechanism allows only a single degree of freedom such that the load cell remains in parallel with the structure.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of U.S. Provisional Application No. 60/497,547, filed Aug. 26, 2003, which is incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The present invention relates generally to bin lifters. More particularly, the present invention relates to a bin lifting and weighing assembly. 
   BACKGROUND OF THE INVENTION 
   Mobile trash and refuse systems are known in the art and are generally used to collect large amounts of garbage or refuse from commercial or residential buildings. With some of these services, there is a cost to the building owners which generally is based on the weight of the trash or refuse being collected. 
   In many cases, the cost for this service is based on a flat monthly fee or set fee per removal. Therefore, regardless of the weight of the trash bin and contents being removed, the owner is charged the same amount. This is quite unfair if an owner is throwing away large items which are lightweight and is charged the same amount as an owner who has a similar sized item which weighs more. This is especially less reasonable when the trash or refuse is simply shredded documents since paper is lightweight. In this manner, owners may find alternatively methods to dispose of their garbage. 
   Rather than being charged a predetermined fee, it would be more beneficial for removal companies to have a garbage or refuse removal system which includes a way to measure the weight of the garbage or refuse being removed so that owners are charged by weight. 
   It is, therefore, desirable to provide a novel bin lifting and weighing assembly. 
   SUMMARY OF THE INVENTION 
   It is an object of the present invention to obviate or mitigate at least one disadvantage of previous bin lifting assemblies. 
   In one embodiment, the bin lifting mechanism is mounted to a support structure to produce a linear axial force on an integral load cell to accurately measure the weight of loads lifted in fixed applications and in mobile applications where angular orientation of the lift mechanism may not be exactly vertical. The mechanism facilitates rapid weight measurement and reduces the amount of parts required for handling motions associated with use of independent scales or devices. 
   A laminated leaf spring mounting arrangement is used and provides a stable geometry that is generally unaffected by static and dynamic frictional forces inherent in mechanical components of the bin lift mechanism. The bin lifting assembly also provides a positive mechanical connection that is able to absorb and withstand the dynamic shock loads of a mobile application. 
   In a first aspect, the present invention provides a means for mounting the bin lifting mechanism against a structure; a load cell, mounted against the structure; for measuring a weight of the bins; wherein the means for mounting the bin lifting mechanism allows only a single degree of freedom such that the load cell remains in parallel with the structure. 
   In a further embodiment, there is provided a weighing assembly comprising means for attaching the weighing assembly to a support structure; means for receiving an item to be weighed; a load cell, mounted against the structure and to the means for receiving an item to be weighed; for weight measurements; wherein the means for attaching the weighing assembly allows only a single degree of freedom such that the load cell remains in parallel with the support structure. 
   Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the present invention will now be described, by way of example only, with reference to the attached Figures, wherein: 
       FIG. 1  is a perspective view of a bin lifting and weighing assembly; 
       FIG. 2  is a side view of the bin lifting and weighing assembly mounted to a support structure; 
       FIG. 3  is an enlarged schematic view of a load cell and mounting means; 
       FIG. 4  is a detailed side view of upper mounting means and the load cell mounted to the support structure in accordance with an embodiment of the invention; 
       FIG. 5  is a side view of lower mounting means mounted to the support structure in accordance with an embodiment of the invention; and 
       FIG. 6  is a schematic diagram of a second embodiment of the bin lifting and weighing assembly. 
   

   DETAILED DESCRIPTION 
   Generally, the present invention provides apparatus for a bin lifting and weighing assembly. The bin lifting and weighing assembly may be attached to a support structure such as a wall of a truck or the sidewall of a large receptacle. 
   Turning to  FIG. 1 , a schematic diagram of a first embodiment of a bin lifting and weighing assembly for attachment to a truck is shown. The assembly  10  comprises a bin lifting mechanism  12  including a pair of, preferably cane shaped, guide rails  14 . The bin lifting mechanism  12  further comprises a pair of chains  16 , preferably double lift, which are integrated within the pair of guide rails  14  and powered by independent drive motors  18  The chains  16  and the motors  18  operate in tandem to drive a carriage  20  from a first, lowered, position to a second, raised, position along the guide rails  14 . In operation, a bin (not shown) is fastened to the carriage  20  via fastening means, such as a hook and a lock, when the carriage  20  is in the first position and then lifted to the second position so that the contents of the bin may be dumped out. Although the bin lifting mechanism  12  has been shown with chains  16  and motors  18 , it will be understood that the bin lifting mechanism may also use extension cylinders or electric actuators to lift the bin from the first position to the second position. Such bin lifting mechanisms will be well known to one skilled in the art. 
   In order to mount the bin lifting mechanism  12  to a support structure, such as a truck wall, the assembly  10  comprises mounting means  22  which includes mounting ears  24 . In the preferred embodiment, there are four sets of mounting means  22  with two mounting ears  24  located on each of the guide rails  14 . The mounting means  22  also comprise stacked leaf springs  23 , preferably a laminated set of three, which provide support for the bin lifting and weighing assembly  10 . The leaf springs  23  allow the bin lifting and weighing assembly to only travel in a single degree of freedom, preferably in the vertical direction, which means that any movement by the bin or support structure during the lifting and weighing process is in the vertical direction. Mounting brackets  25  are also used to assisting in the mounting of the assembly  10 . 
   The mounting means  22  are selected such that they only allow movement of the assembly in one direction, namely vertical. By providing only one degree of freedom of movement, regardless of the movement of the support structure, the weight of the bin and its contents, or payload, may be more accurately measured. This will be described in more detail below. 
   When the assembly  10  is mounted to the support structure, such as a mobile shredding truck, the assembly  10  is attached to a pair of mounting bars  26  so that the mounting bars  26  provide further support to the assembly. The mounting bars  26  provide support to the entire assembly to reduce deflection by the assembly during the lifting and weighing process and are preferably perpendicular to the guide rails  14 . As more clearly shown in  FIG. 2 , when the bin lifting and weighing assembly  10  is mounted against a support structure, the mounting bars  26  are located on the opposite side of a truck wall  28  away from the assembly  10  to provide further support to the mounted assembly  10 . In this embodiment, fastening means such as screws are used to fasten the assembly to the mounting bar  26  through the truck wall  28 . 
   As more clearly shown in  FIGS. 4 and 5 , which are enlarged schematics of the circles in  FIG. 2 , the leaf springs  23  are attached to the mounting bars  26  via the mounting bracket  25  while the mounting ear  24  is attached to the clamp plate  27  with the leaf spring  23  therebetween via fastening means  29 . 
   In order to weigh the contents in the bin, along with the bin, the bin lifting and weighing assembly  10  further comprises weighing means  30 . The weighing means  30  comprises a load cell  32  which is preferably mounted in a vertical orientation (to the ground) between a first yoke  34  and a second yoke  36  as more clearly shown in  FIG. 3  which is an enlarged schematic diagram of the weighing means. Anti-friction bearings  38  are also mounted at the joints between the yokes  34  and  36  and the load cell  32  in order to reduce the forces acting on the load cell which may affect the measurement of the bin and its contents. 
   The second yoke  36  is anchored to a base structure  40  mounted to one of the mounting bars  26   a  while the first yoke  34  is attached to the guide rails  14  via a connecting structure  42 . 
   The load cell  32  measures the combined weight load of the bin lifting mechanism and the bin along with the payload (contents) within the bin. By having the load cell  32  and the mounting means  22  anchored to the same support structure, any movement by the support structure causes a similar motion by the load cell  32  and the mounting means  22 . By maintaining the load cell  32  in axial alignment with the plane of the support structure, the weight measurements measured by the load cell  32  are more accurate than other prior art systems since the forces acting on the bin and its contents is restricted to the vertical direction. Furthermore, in the present invention, only a single load cell is required to obtain a weight measurement of the bin and its contents while many prior art systems require multiple load cells. The leaf springs  23  limit the side-to-side motion of the bin during the lifting process and allow only unidirectional deflection parallel to the force being experience by the load cell  32 . 
   In order to assist in the weighing process, the mounting ears  24  distribute the forces experienced by the lifting assembly so that the force is shared over the assembly  10  to reduce the wear and tear on the parts of the assembly. 
   Turning to  FIG. 6 , a second embodiment of the bin lifting and weighing assembly is shown including apparatus for displaying or recording the measured weight is shown. The apparatus  50  comprises the bin lifting and weighting assembly  10  (as described above) with the load cell  32 . The load cell  32  communicates with a processing means  52  which is connected to a database  54  and/or a display  56  such as an LCD display. 
   In operation, in one embodiment, a bin, containing material which is to be measured and dumped, is attached to the carriage  20  of the bin lifting and weighing assembly  20  while the carriage  20  is in the first, lowered, position. A bin lifting and weighing assembly operator then activates the assembly  10  to move the bin from the first, lowered, position to the second, raised, position. At a predetermined location, operation of the assembly is halted and a weight measurement taken by the load cell  32  The load cell  32  then transmits an electric signal corresponding to the measured weight which is then received by the processing means  52  and displayed on a display  56  or stored in a database  54 . After the weight measurement has been retrieved, the operator re-starts the assembly  10  and the bin travels to the second, raised, position where the contents are dumped into a larger receptacle. 
   As will be understood, during the lifting process, the mounting means  22  only allow movement of the assembly, including the bin, in the vertical direction so more accurate measurements are retrieved by the load cell  32 . 
   Alternatively, the measurements may be taken dynamically without having to stop the lifting process so that the entire lifting and weighing process may be automated without requiring operator assistance outside of the initial attachment of the bin and the initiation of the lifting and weighing process. 
   Furthermore, the processing and display means described above may be a programmable logic control and a screen or a dedicated display corresponding to the load cell. In another embodiment, the electrical signal produced by the load cell (representing the weight measurement) may be transmitted directly or over a telemetry system to a main computer, acting as a processor, which automatically records the measurement and stores it in a database for further processing or displays it to a screen. 
   An advantage of the present invention is that it is less costly to manufacture since the parts are readily available to builders and only one load cell is required. 
   Alternatively, it will be understood that the bin lifting assembly may only require a single guide rail. The number of guide rails and lift chains required for the bin lifting assembly is determined by the size and weight of bins which the assembly is designed to lift. Therefore, for smaller and lighter bins, only one guide rail may be used while for larger bins, the double guide rail system may be employed. Similarly, the number of mounting ears may be variable to suit the bin lifting assembly requirements. 
   Other bin lifting mounting arrangements that produce similar desired characteristics of providing lateral support while also providing linear axial force on the load cell may include double hinge, sliding connection or linear bearings. 
   Furthermore, the use of the leaf springs reduces the likelihood of an overturning moment occurring. 
   Alternatively, if the support structure is a rigid mounting surface, there may be no need for the mounting bars  26  and the mounting means  22  may be fastened directly to the stationary wall since there is less opportunity that the support structure will move during the bin lifting and weighing process. 
   The design is flexible and suitable for mounting bin lifter that may be constructed in other designs common to the art. The structure is robust and suitable for use in industrial and mobile applications where shock loads are probable. A typical application, for example, is a mobile shredding truck where the bin lifting is used to lift bins full of material to be shredded on location. 
   The above-described embodiments of the present invention are intended to be examples only. Alterations, modifications and variations may be effected to the particular embodiments by those of skill in the art without departing from the scope of the invention, which is defined solely by the claims appended hereto.