Abstract:
A snap fit belt guard for a power trowel is disclosed, wherein the means for securement includes a series of slots and corresponding tabs. In some embodiments, the belt guard is manufactured, preferably of a pliable material, with the tabs farther apart than the slots, and the belt guard is squeezed to enable the tabs to fit into the slots. When the pressure is released, the belt guard is locked into place.

Description:
RELATED APPLICATION  
       [0001]     This application claims priority to U.S. Provisional Patent Application No. 60/644,920, filed Jan. 18, 2005 and entitled SNAP FIT BELT GUARD FOR POWER TROWELS, the disclosure of which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND  
       [0002]     Concrete power trowels are used for finishing concrete surfaces as the concrete is curing and hardening. A typical power trowel has a rigid frame which houses at least one blade assembly, and an engine. The engine is usually a gasoline or diesel engine, and is used to provide the motive power for the blade assembly. Other potential “engines” include, but are not limited to, electric motors and hydraulic motors. For “riding” models, an operator&#39;s seat and the necessary control systems and levers for operation of the trowel are positioned atop of the engine and the frame assembly. These machines are manufactured in a variety of sizes and weights, with the largest of these machines having not just two, but rather three, rotor and troweling blade assemblies.  
         [0003]     Power trowels have belts that drive the blades. The belts often become frayed or even tear. In order to facilitate replacing the belts, power trowels generally have removable belt guards. The belt guard is typically a shell of metal, plastic, or other rigid material that envelops the belt/pulley drive to protect people near the drive from injuries. The belt guard must be removed in order to evaluate the condition of the drive system and maintain the components including the belt.  
         [0004]     In order to be removable, belt guards require fasteners, the fasteners usually being nuts and bolts. Removing a belt guard attached with nuts and bolts requires a wrench. Removing the nuts and bolts with a wrench is time consuming, requires that the operator carry a wrench, and creates the possibility that the wrench, nuts, or bolts may become lost. Often, the belt guards are removed once and never replaced, which creates the risk of injury due to the exposure of the belt and other moving components.  
       SUMMARY  
       [0005]     The above-mentioned drawbacks associated with existing belt guards for power trowels are addressed by embodiments of the present invention, which will be understood by reading and studying the following specification.  
         [0006]     In one embodiment, a belt guard comprises a body having a hollow area configured to enclose components of a drive system of a power trowel and at least one tab extending from the body. The at least one tab is configured to frictionally engage with at least one slot on the power trowel. In addition, the belt guard is made of a pliable material.  
         [0007]     In another embodiment, a power trowel comprises a frame housing at least one blade assembly, an engine, and a drive system comprising a plurality of components, the drive system being configured to enable the engine to power the at least one blade assembly. The power trowel further comprises a belt guard enclosing at least one component of the drive system. The belt guard comprises a pliable material, and is connected to the power trowel by frictional engagement of slots and tabs.  
         [0008]     In another embodiment, a system for retrofitting a removable belt guard onto a power trowel comprises a mounting plate comprising a plurality of slots and a belt guard comprising a plurality of tabs. The belt guard comprises a pliable material and further comprises a hollow area configured to enclose components of a drive system of the power trowel. The tabs are configured to frictionally engage the slots when the belt guard is in a compressed state.  
         [0009]     These and other embodiments of the present application will be discussed more fully in the detailed description. The features, functions, and advantages can be achieved independently in various embodiments of the present application, or may be combined in yet other embodiments. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIGS. 1A and 1B  illustrate a mounting plate configured to cooperate with a belt guard, in accordance with one embodiment of the present application.  
         [0011]      FIGS. 2A and 2B  illustrate a belt guard configured to be mounted on a power trowel, in accordance with one embodiment of the present application.  
         [0012]      FIGS. 3A and 3B  are schematic drawings illustrating how the belt guard shown in  FIG. 2  can be engaged with the mounting plate shown in  FIG. 1 , in accordance with one embodiment of the present application.  
         [0013]      FIGS. 4A and 4B  illustrate the belt guard of  FIG. 2  engaged with the mounting plate of  FIG. 1 , in accordance with one embodiment of the present application.  
         [0014]      FIG. 5  illustrates a power trowel including a mounting plate and a belt guard, in accordance with one embodiment of the present application. 
     
    
       [0015]     Like reference numbers and designations in the various drawings indicate like elements.  
       DETAILED DESCRIPTION  
       [0016]     In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific illustrative embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that various changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense.  
         [0017]     The present application relates to a system and method for enclosing a belt and other components of a drive system for a power tool, such as a power trowel. In some embodiments, the system comprises two pieces. The first piece is illustrated in  FIGS. 1A and 1B , and is called a mounting plate  30 . The mounting plate  30  attaches directly to the power trowel  50 , and may be retrofitted onto existing power trowels  50 . The mounting plate  30  is preferably made of metal, but may be made of any other durable, rigid material.  
         [0018]     In some embodiments, the mounting plate  30  has four small holes  44  which allow it to be bolted onto a power trowel  50 . The mounting plate  30  can also include a first larger hole  40  on its narrow end which allows the mounting plate  30  to function as a lift bale, and can be configured to receive a hook so that a crane can lift the power trowel  50 , as shown in  FIG. 5 . The mounting plate  30  preferably also has a second larger hole  42  surrounded by the four small holes  44 . In some embodiments, the mounting plate  30  also has three straight slots  32 ,  34 ,  36 , which are configured to receive straight tabs  12 ,  14 ,  16 , from the second piece, called the belt guard  10 , which is illustrated in  FIGS. 2A and 2B . In addition, in some embodiments, such as the exemplary embodiment illustrated in  FIGS. 1A and 1B , the mounting plate  30  also comprises a curved slot  38 , which is configured to receive a curved tab  18  from the belt guard  10 . The straight slots  32 ,  34 ,  36 , are preferably located near the perimeter of the mounting plate  30 .  
         [0019]     Referring to  FIGS. 2A and 2B , the belt guard  10  is preferably made of plastic, but may be made of metal or any other material which is pliable enough for human hands to bend the belt guard  10 , yet rigid enough to spring back into position. The belt guard  10  has a hollow area  20  configured to enclose the belt and other components of the drive system, as illustrated in  FIGS. 4 and 5 .  
         [0020]     In some embodiments, the belt guard  10  comprises four tabs  12 ,  14 ,  16 ,  18 , that fit into the four slots  32 ,  34 ,  36 ,  38  on the mounting plate  30 . The curved tab  18  extends directly away from the belt guard  10 . The three straight tabs  12 ,  14 ,  16 , are preferably located on the bottom of the belt guard  10  that faces toward the mounting plate  30 . The three straight tabs  12 ,  14 ,  16 , preferably extend directly away from the belt guard  10 , but then bend in a direction slightly greater than ninety degrees, so that they are extending away from the center of the belt guard  10 , as shown in  FIGS. 2A and 2B .  
         [0021]     By manually squeezing the belt guard  10 , the tabs  12 ,  14 ,  16 , become close enough together for the tabs  12 ,  14 ,  16 , all to fit into the slots  32 ,  34 ,  36 , on the mounting plate  30 , as illustrated in  FIGS. 3A and 3B . When the pressure is released, the belt guard  10  springs back into its normal shape. Thus installed, the belt guard  10  remains in slight compression so that the tabs  12 ,  14 ,  16 , are constantly urged outwardly to frictionally engage the outside edges of the slots  32 ,  34 ,  36 , as shown in  FIGS. 4A and 4B . The bend to the straight tabs  12 ,  14 ,  16 , improves the compression fit. The belt guard  10  can also be removed by manually squeezing the belt guard  10  so that the tabs  12 ,  14 ,  16 , disengage the slots  32 ,  34 ,  36 .  
         [0022]     The distance between the straight tabs  12 ,  14 ,  16 , on either side of the belt guard is preferably greater than the distance between the straight slots  32 ,  34 ,  36 , on the mounting plate  30 . The difference between the distances is preferably great enough to cause the tabs  12 ,  14 ,  16 , to frictionally engage the slots  32 ,  34 ,  36 , when the belt guard  10  is released and allowed to spring back into its normal shape, yet small enough for a person to be able to manually squeeze the tabs  12 ,  14 ,  16 , together so that they will fit into the slots  32 ,  34 ,  36 . In some embodiments, this difference is approximately one-eighth of an inch.  
         [0023]     In some embodiments, the system described herein may be retrofitted onto existing power trowels  50  by attaching the mounting plate  30  to the power trowel  50  with nuts and bolts utilizing the four small holes  44 . However, it is envisioned that the present invention could be carried out without the mounting plate  30 . Instead, another part of the power trowel  50 , such as the engine or gear box, could be originally fitted with slots that were configured to receive the tabs  12 ,  14 ,  16 ,  18 , of the belt guard  10 . Also, the tabs  12 ,  14 ,  16 , on one side of the belt guard  10  could be replaced with a hinge. Then, instead of the belt guard  10  being removed from the power trowel  50 , the belt guard  10  would swing away and allow viewing and access to the drive system. Also, the slots  32 ,  34 ,  36 ,  38 , and tabs  12 ,  14 ,  16 ,  18 , could be exchanged, i.e., the mounting plate  30  could have tabs, and the belt guard  10  slots. This invention could also be applied to other apparatuses with a cover that needs to be removed and replaced.  
         [0024]     The systems and methods described herein present a number of distinct advantages over conventional belt guards. For example, by implementing the systems and methods described herein, workers&#39;time can be saved because it is quicker to remove and replace the belt guard  10  by the present method. It is not necessary to remove the mounting plate  30  to access the belt or other components of the drive system. In addition, no wrenches are required to be carried by the worker, and the possibility of losing fasteners such as nuts and bolts is advantageously eliminated.  
         [0025]     Although this invention has been described in terms of certain preferred embodiments, other embodiments that are apparent to those of ordinary skill in the art, including embodiments that do not provide all of the features and advantages set forth herein, are also within the scope of this invention. Accordingly, the scope of the present invention is defined only by reference to the appended claims and equivalents thereof.