Abstract:
A power cord retaining system for use with a power tool configured for accommodating an extension cord includes a cord capture formation for retaining the extension cord disposed on the tool, and a cord channel disposed on the tool and configured for supporting a loop of the cord substantially along an arc defined by the loop. In the preferred embodiment, the cord capture formation defines an enclosed aperture for retaining the cord at two points, defining a cord loop therebetween, and the cord channel defines a semi-circular arc for supporting the cord loop substantially along its apex. A cord lock is preferably formed in association with the cord channel for releasably locking the cord in the channel and preventing unwanted cord release.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates generally to portable electric power tools designed for use with extension cords, and specifically to a system for securely retaining the extension cord to the tool in a way which reduces stress on the cord.  
           [0002]    Conventional portable electric power tools, including but not limited to drills, hammer drills, sanders, grinders, circular saws, reciprocating saws, routers, power fastener drivers, garden weed trimmers, leaf blowers and the like are typically provided with a power cord which, depending on the manufacturer and model, varies in length from about six inches to about 12 feet. Regardless of the length of the standard equipment cord or tool cord, users often need to employ extension cords to reach remote work sites. For example, on construction sites, long extension cords are often connected to portable generators. In such cases, if the extension cord is merely plugged into the tool cord, pulling on the tool, which often occurs during use, may cause the extension cord to become detached from the tool cord, which disrupts work and is frustrating to the operator. Also, the junction of the tool cord and the extension cord often becomes caught on workplace obstructions, causing the tool to become disconnected from the extension cord.  
           [0003]    To address this problem, operators often tie adjacent ends of the extension and tool cords together in a knot. While making a more secure junction, the knot has a tendency to become caught on workpiece edges or on other surfaces, requiring the operator to interrupt work and free the caught knot. Another disadvantage of the knot is that it requires tight bends to be made in both the tool cord and the extension cord. Repetitive sharp bending stresses of this type cause stresses on the internal wiring of the cords and may result in fraying of the cords and/or short circuits.  
           [0004]    One attempted solution to this problem is to provide a tool which lacks a tool cord, but instead has an electric receptacle for directly receiving an extension cord. While this solution removes the problems associated with the extension cord-tool cord knot, a new problem is introduced in that pulling on the tool during work or movement causes the extension cord to become detached from the tool. Again, work is interrupted, which is often frustrating to the operator.  
           [0005]    To address the problem of retention of the extension cord on the tool, tools have been provided with cord retention systems. Such systems are typically configured with formations such as hooks and/or loops which bend the extension cord in a serpentine manner near the tool receptacle and thus isolate the cord plug from a pulling action on the cord. In this manner, pulling on the tool while attached to the cord will not cause the extension cord to become unplugged from the tool.  
           [0006]    However, such conventional systems are often unsatisfactory because they cause excessive and/or sharp bends in the cord, which shorten the life of the extension cord and may cause short circuits. Such stresses occur when the cord is forced into sharp bends around hooks or other projections. One related and important design criteria of such systems is that construction workers working on ladders or on second stories of buildings often raise and/or lower the tool by the cord. Especially with heavier tools, this places a significant load on the cord. When the cord has sharp bends, particularly where the cord leaves the retention system, there is excessive and potentially damaging stress placed on the cord. This problem is especially severe where the retention system creates a right angle bend in the cord as it exits the system. In instances where the tool has a tool cord, the stresses are severe enough to cause the tool cord to be pulled out of the tool.  
           [0007]    Another disadvantage of conventional cord retention systems is that the cord is not sufficiently secured in the system. One problem resulting from this disadvantage is that when a tool is moved backward, as in a sawing motion, a slack condition in the extension cord may cause the cord to become disengaged from portions of conventional systems. Another problem is that when operating in heavy vegetation or crowded work environments, the many cord loops created by conventional systems are prone to becoming caught on branches or other environmental obstructions, which may cause the cord to become detached from the retention system.  
           [0008]    Still another disadvantage of conventional extension cord retention systems relates to the fact that extension cords are provided in a variety of gauges or thicknesses. Conventional cord retention systems are incapable of accommodating a wide range of cord gauges.  
           [0009]    Accordingly, an object of the invention is to provide an improved cord retention system for a power tool which reduces stress on the cord, especially when the cord is used to raise and/or lower the tool.  
           [0010]    Another object of the present invention is to provide an improved cord retention system for a power tool which positively secures the cord to the tool.  
           [0011]    Still another object of the present invention is to provide an improved cord retention system for a power tool which accommodates a range of extension cord gauges.  
         BRIEF SUMMARY OF THE INVENTION  
         [0012]    The above-listed objects are met or exceeded by the present power tool extension cord retention system, which features an arrangement where the retained extension cord is subjected to only gradual loops so that sharp turns and kinks are avoided. Furthermore, the formed cord loop is supported in a way that minimizes stress on the cord when the cord is pulled, as when the tool is urged forward during work, or the cord is used to raise or lower the tool from an elevated work place. In addition, a cord lock is provided to the present system to secure the cord in place during both loaded and slack cord conditions.  
           [0013]    More specifically, the present invention provides a power cord retaining system for use with a power tool configured for accommodating an extension cord. The system includes a cord capture formation for retaining the extension cord disposed on the tool, and a cord channel disposed on the tool and configured for supporting a loop of the cord substantially along an arc defined by the loop.  
           [0014]    In the preferred embodiment, the cord capture formation defines an enclosed aperture for retaining the cord at two points, defining a cord loop therebetween, and the cord channel defines a semi-circular arc for supporting the cord loop substantially along its apex. A cord lock is preferably formed in association with the cord channel for releasably locking the cord in the channel and preventing unwanted cord release.  
           [0015]    In another embodiment, a power cord retaining system is provided for use with a power tool configured for accommodating an extension cord, and includes a cord channel disposed on the tool and defining a radius configured for supporting a loop of the cord substantially along an arc defined by the loop. In yet another embodiment, a power cord retaining system is provided for use with a power tool configured for accommodating an extension cord. The system includes a cord capture formation for retaining the extension cord disposed on the tool and a cord channel disposed on the tool and configured for supporting a loop of the cord substantially along an arc defined by the loop. The capture formation and the channel are disposed on the tool so that the cord engages the system along an axis which is parallel to a longitudinal axis of the tool. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0016]    [0016]FIG. 1 is a front perspective view of a tool handle incorporating the present system;  
         [0017]    [0017]FIG. 2 is a rear perspective view of the tool handle of FIG. 1;  
         [0018]    [0018]FIG. 3 is a bottom view of the tool handle of FIG. 1 shown with an extension cord in place;  
         [0019]    [0019]FIG. 4 is a fragmentary side view of the present system showing a cord lock feature;  
         [0020]    [0020]FIG. 5 is a side view of a tool featuring an alternate arrangement of the present system; and  
         [0021]    [0021]FIG. 6 is a fragmentary rear view of the tool of FIG. 1 showing the cord loop planes defined by the present system. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]    Referring now to FIGS.  1 - 3 , a power tool generally designated  10  is shown fragmentarily, and is contemplated as being any one of a group of commonly known portable electric power tools, including, but not limited to drills, hammer drills, sanders, grinders, circular saws, reciprocating saws, routers, power fastener drivers, garden weed trimmers, leaf blowers and the like, all being commercial or homeowner-type power tools commonly used with an extension cord, generally designated  12  (best seen in FIG. 3). The extension cord  12  is of the type commonly used in conjunction with wall sockets or portable generators used on job sites. The length of the cord  12  may vary as well as its gauge or diameter and still be suitable for use with the present invention. However, for commercial applications, the extension cord  12  will typically be made of 10, 12 or 14 gauge cable.  
         [0023]    The power tool  10  has a handle portion  14  and an actuator trigger  16 . In the preferred embodiment, the handle portion  14  is made of molded rigid plastic, however, other suitable materials are contemplated such as cast aluminum, stainless steel, etc. as are well known in the tool art. If provided, the configuration of the handle portion  14  and the trigger  16  may vary to suit the application. Opposite the tool handle portion  14  is a working end  18  (shown in phantom in FIG. 1) which includes components (not shown) as are known in the art for performing the designated work desired for a particular tool.  
         [0024]    In the preferred embodiment, the cord retaining system, generally designated  20 , is secured to the handle portion  14 , as by being integrally molded thereto. However, other types of attachment are contemplated, including chemical adhesives and threaded fasteners. Two main components make up the cord retaining system  20 , a cord capture formation  22  and a chord channel  24 . The cord capture formation  22  is configured for retaining the extension cord  12  at at least two points of contact  26 ,  28  (FIG. 3), with a loop portion  30  of the cord formed between the two points. The cord channel  24  receives and supports an apex  32  of the loop portion  30 .  
         [0025]    More specifically, the cord capture formation  22  is configured to define an enclosed space  34  when attached to the tool  10 . Thus, the capture formation  22  may define a circular, oval, free form or other preferably non-cornered shape on its own or using a portion  36  of the tool  10  (depicted as part of the handle portion  14 ). A non-cornered shape is preferred to avoid sharp edges which may cause wear or stress on the extension cord  12 .  
         [0026]    The capture formation  22  includes first and second ends also termed front and rear ends  38 ,  40 . An important feature of the present cord capture formation  22  is that at least one and preferably both of the ends  38 ,  40  are configured with a fully radiused or rounded edge  42  to prevent unnecessary wear or stress on the extension cord  12 . Further, as will be seen in FIG. 2, the ends  38 ,  40  are outwardly flared to further promote ease of insertion and retention of the cord  12 .  
         [0027]    Another aspect of the cord capture formation  22  is that it is preferably located in close proximity to an electrical receptacle  44  which is preferably integrally joined to the handle portion  14 , however other configurations are contemplated depending on the application. It will be seen that the tool  10  defines a longitudinal axis, and the cord capture formation  22  is preferably oriented on the tool  10  so that the enclosed space  34  is coaxial or parallel to the longitudinal axis of the tool. While the cord capture formation  22  is shown preferably positioned on a lower end  46  of the tool  10 , it is contemplated that other positions may be suitable, including on one side  48  of the tool, depending on the application.  
         [0028]    Referring now to the cord channel  24 , the other portion of the present retention system  20 , an important feature of the present system is that the cord channel  24  supports the apex  32  of the loop portion  30  along a substantial portion of its length. To that end, and so that kinks and sharp bends in the extension cord  12  are prevented, the cord channel  24  is preferably formed into a semi-circle which depends from the lower end  46  of the tool  10 . In addition, the cord channel  24  defines an arcuate or “C”-shaped groove  50  (best seen in FIG. 4) which is curved along its vertical dimension to accept the profile of the extension cord  12 . It is preferred that leading and trailing edges  52 ,  54  of the cord channel  24  are inclined to facilitate cord placement. Also, to prevent excessive cord wear, an outer lip  56  of the channel  24  is also radiused.  
         [0029]    Referring now to FIGS. 3 and 5, for best results, the cord capture formation  22  and the cord channel  24  are linearly aligned on the tool  10  along a major tool axis. In the embodiment of FIG. 3, the capture formation  22  and the cord channel  24  are aligned along the longitudinal tool axis “N”. However, in FIG. 5, the capture formation  22  and the cord channel  24  are disposed along an axis “M” defined by the handle portion  14  of a generally “L”-shaped tool  10   a . The other major axis is designated “N” for the tool  10   a . Thus, some tools may have a single major axis, that being the longitudinal axis, but other tools may have two major axes, as in the case of “L”-shaped tools  10   a.    
         [0030]    Also, given that the tool  10 ,  10   a  generally defines a vertical plane, the system  20  is constructed and arranged so that the cord capture formation  22  and the cord channel  24  are in operational relationship to each other on the tool  10 ,  10   a  to restrain the cord loop of cord in a cord plane “P” which is generally parallel to the corresponding major axis of the tool. Also, the formation  22  and the channel  24  are spaced apart a sufficient distance for allowing the cord  12  to easily clear the formation  22  and engage the channel  24  without kinking or bending, other than forming the loop portion  30 . It will be seen from FIGS. 3 and 5 that it is also preferred that the cord channel  24  is closer to the working portion  18  of the tool  10  than the cord capture portion  22 .  
         [0031]    Once the cord  12  is secured in the receptacle  44  and in the system  20 , it will be seen that the retained cord forms only two loop planes, the plane P and a second plane Q which is generally inclined relative to the plane P (best seen in FIG. 6). The degree of inclination of the plane Q to the plane P may vary to suit the application. By minimizing the number of cord loop planes, kinking and sharp bending of the cord  12  is prevented.  
         [0032]    Referring now to FIG. 1, another feature of the present system  20  is that once in the cord channel  24 , the extension cord  12  is releasably locked in place by a cord lock  60 . As illustrated, the cord lock  60  is preferably a biased locking tab which is integrally formed with the cord channel  24 . However, it is contemplated that the cord lock  60  could take other forms, including clips, hinges, latches, wedges, any of which retain the cord in place in the channel  24 . In the preferred embodiment, the cord  12  is retained in the groove  50  by a snap fit provided by the lock  60 .  
         [0033]    Referring now to FIG. 4, since it is contemplated that the system  20  may be used with extension cords  12  having a variety of gauges, if the dimensions of the cord channel  24  and, particularly, the cord lock  60  are fixed, there is a possibility that if the cord lock is configured for a larger diameter cord, then if a smaller diameter cord is used, it may not be properly retained. To that end, a cord lock latch  62  is provided, in which a latch member  64  engages a catch  66  in the lower end  46  of the tool  10 . As is known in the art, the latch member  64  is preferably pivotable relative to the cord channel  24 , such as by being integrally molded to form a “living hinge”, or joined to the channel with a pivot pin (not shown). To further accommodate a variety of cord gauges, the latch member  64  may be provided with a resilient pad  68  for taking up extra space between the latch member and the cord  12  if needed.  
         [0034]    To secure the cord  12  in the tool  10 , the user forms the loop  30  in the cord near a plug  70  and inserts the loop through the cord capture formation  22 . The loop  30  is then placed around the cord channel  24  and is pressed into the groove  50 . The cord lock  60  or  62  secures the cord  12  in place in the groove  50 . Next, the plug  70  is engaged in the receptacle  44  as is well known in the art. As seen in FIGS. 3 and 5, if a load “L” is placed on the cord  12  while secured to the tool  10  by the present system  20 , such as when the tool is lowered or raised by the cord  12  from an elevated location, it will be seen that the cord is not subject to stresses caused by sharp bends or kinks.  
         [0035]    While a particular embodiment of the present extension cord retention system for a power tool has been described herein, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.