Abstract:
Disclosed is a battery-powered grass and weed trimming device including a housing portion with a handle portion and a shield portion. A first switch is disposed on a top side of the housing and a second switch is disposed on the bottom side of the housing. The second switch acts as a safety interlock to avoid accidental actuation of the device. A hub is disposed adjacent to the shield and retentively maintains a filament. A motor forcefully rotates the filament for cutting grass and weeds. The trimming device is packaged for sale in a sealed package having a feature that permits a prospective purchaser to momentarily operate the tirmmer while it is still in the package. The trimmer includes an optional wheeled extension handle to which the trimmer can be mounted to allow a user to use the trimmer while standing.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/617,407, filed Oct. 8, 2004. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a weed and grass trimmer, and more particularly, to a handheld, battery-powered weed and grass trimmer.  
         [0004]     2. Description of Related Art  
         [0005]     Power tools for trimming lawns and cutting weeds are well-known in the prior art. A variety of such tools includes cordless types of tools that operate on battery power. These tools are convenient for trimming and edging lawns, and for cutting weeds that grow near lawns, gardens, and other tended areas. Most such trimming tools have extended handles for use in the upright position. Others have combustion engines, while still others have electrical cord attachments. Existing grass and weed trimming power tools are not compact or lightweight enough to trim in very confined outdoor spaces, such as around shrubbery, walls, and poles. Further, with extended handles, existing devices are unwieldy for adjusting the angle at which the trimmer filament segment may be directed to the weeds or grass to be cut.  
         [0006]     Further, existing battery-powered grass and weed trimmers utilize rechargeable, heavy-duty batteries for extended battery life. Because of the sheer weight and size of these trimmers, it has been heretofore impractical to use standard, non-rechargeable, general-purpose alkaline or similar dry cell batteries. These devices in the past have simply consumed more power than non-rechargeable alkaline batteries were capable of producing.  
         [0007]     Hence, there exists a need for a compact, portable, handheld, battery-powered grass and weed trimming tool.  
       SUMMARY OF THE INVENTION  
       [0008]     The device of the present invention is a novel grass and weed trimming device. By reducing the size and corresponding power consumption of the device, it is practical to power the device using standard non-rechargeable, general purpose alkaline or similar dry cell batteries. Alkaline batteries are inexpensive and plentiful, and allow a sufficient operating life for the present invention.  
         [0009]     The present invention is a grass and weed trimming device having a housing portion. The housing portion has a handle portion and a shield portion attached to the housing portion. There is a cavity disposed within the handle portion for housing a power source.  
         [0010]     The device is controlled by two switches—a first switch disposed on the top side of the housing and a second switch disposed on the bottom side of the housing. The second switch acts as a safety interlock to avoid accidental actuation of the device. Preferably, first switch and second switch must be engaged in order to conduct power from the power source to energize a motor.  
         [0011]     There is hub disposed adjacent to the shield having an aperture for retentively maintaining a filament section. The motor is electrically coupled to the power source by the switches for impelling the hub to forcefully rotate the filament section for cutting grass, weeds, and other similar material.  
         [0012]     In one embodiment of the present invention, the filament segment has a shaped end, and the aperture is adapted for retentively receiving the shaped end to maintain the filament in position on the hub during operation of the device.  
         [0013]     The handle portion of the housing is adapted to fit into a hollow cylindrical socket of an extension handle. The handle portion also has a jack input or other means to electrically link the shear to the handle for transferring the power switch control to the extension handle.  
         [0014]     The present invention further provides a sealed package for the grass shear, which is packaged with batteries installed.  
         [0015]     The device may be enclosed within a clamshell package with a protrusion adjacent to and applying pressure to the second switch such that the second switch remains engaged while contained within the package, with the first switch being operable through the surface of the package so that the device may be operated while contained therein.  
         [0016]     In another embodiment, the package includes a transparent blister. The blister provides openings through which a purchaser can actuate both the first and second switches in order to turn the motor on and observe the operation of the shear in the package.  
         [0017]     It is an object of the present invention to provide a compact, portable, handheld, and battery-powered or cordless tool for trimming grass, weeds, and the like. Another object of the present invention is to provide a safety feature comprised of a pair of switches that must be closed simultaneously in order to operate the device. Yet another object of the present invention is to provide a novel filament segment for cutting and a hub aperture for receiving said filament segment. A further object of the present invention is to provide a low-power tool that operates efficiently on non-rechargeable batteries, such as alkaline or similar general-purpose batteries. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]      FIG. 1  is a side elevational view of the novel grass and weed trimming device of the present invention;  
         [0019]      FIG. 2  is a plan view of the trimming device;  
         [0020]      FIG. 3  is a top plan view of the trimming device shown with a battery compartment detached from a housing;  
         [0021]      FIG. 4  is an illustration of a filament segment attachment to a hub of the trimming device;  
         [0022]      FIG. 5  is a sectional view illustration of the filament segment attachment to the hub shown in  FIG. 4 ;  
         [0023]      FIG. 6  is a bottom view of a shield showing the filament segment and hub;  
         [0024]      FIG. 7  is a perspective view of the filament segment and hub;  
         [0025]      FIG. 8  is a side elevational view of the trimming device being connected to an extension handle;  
         [0026]      FIG. 9  is a top plan view of the trimming device in a sealed package designed to allow a potential purchaser to momentarily operate the shear in the package; and  
         [0027]      FIG. 10  is a side elevational view of the trimming device in a sealed package, showing a cross section of the package, which is designed to allow a potential purchaser to momentarily operate the shear in the package. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0028]     Referring, to  FIGS. 1-3 , a weed and grass trimmer is generally designated as  10 . A hollow, curved housing  12  has a shield  14  attached at one end, which covers a trim filament  46  and a hub  44 . Shield  14  partially covers the filament  46  and hub  44  to protect the user&#39;s hand when the trimmer  10  is operating.  
         [0029]     At a butt end of housing  12  is a removable cap  16  for insertion of batteries  17  to power the trimmer  10 . A push-button switch  18  is provided for energizing a small DC motor  19  from the batteries  17 . A raised collar  22  is provided on the housing  12  surrounding push-button switch  18  to prevent accidental actuation. Also provided is a safety-interlock switch  20  located on the bottom of housing  12  opposite push-button switch  18 . The trimmer  10  requires the operator to intentionally engage both push-button switch  18  and safety-interlock switch  20  in order to energize the motor  19 , thus preventing inadvertent or accidental actuation of trimmer  10 . In a preferred embodiment, safety-interlock switch  20  must be engaged first and must remain engaged during engagement of push-button switch  18 . When push-button switch  18  is released, operation of the trimmer  10  ceases. Safety-interlock switch  20  also provides the ability to have a test or “try-me” feature while the trimmer  10  is in a package, so that a shopper may operate the trimmer  10  while it is still within the packaging in a store. This feature will be discussed in greater detail below.  
         [0030]     A function of safety-interlock switch  20  is to avoid inadvertent actuation by, for example, placing the trimmer  10  on a surface with the push-button switch  18  side down. It would be possible for the push-button switch  18  to actuate the trimmer  10  alone, except for the requirement of engaging safety-interlock switch  20 . Without safety-interlock switch  20 , the trimmer  10  could accidentally run in the inverted position, due to the weight of the trimmer  10  pressing on the push-button switch  18 . While collar  22  is designed to prevent, to some extent, that particular occurrence, if the surface upon which the trimmer  10  is inadvertently laid is irregular, collar  22  may not be effective in preventing accidental actuation. Thus, the position of safety-interlock switch  20  underneath opposite push-button switch  18  requires the user&#39;s thumb to operate push-button switch  18  and forefinger or other finger to grip the barrel of housing  12 , so that the safety-interlock switch  20  is depressed simultaneously with push-button switch  18  in order to operate the trimmer  10 .  
         [0031]     Shield  14  has a partially-circular shape in the plan view, with a sector of the circle cut away  24 , so as to expose a free end of the filament  46  to permit contact between the filament  46  and weeds or grass. Shield  14  may also optionally include a rotational feature, which allows the shield  14  to rotate partially or completely around the axis of the shield  14 . If a partial rotation is used, it permits travel from one stop limit  26  to opposing stop limit  28 , which enables the user to direct the cut away portion  24  to the side to which weeds or grass are to be cut.  
         [0032]     It should be noted that a particular advantage of the disclosed embodiment is the use of disposable alkaline batteries  17  to power the small, DC motor  19  that drives the hub  44  that holds the filament  46 . A variety of types of batteries  17  may be used, including general purpose alkaline and high-power lithium, and rechargeable batteries, such as nickel metal hydride or nickel cadmium batteries.  
         [0033]     The filament  46 , as shown in  FIGS. 4-7 , is attached to the hub  44  and rotates with hub  44 , which is attached to the motor  19 . While the trimmer  10  may operate with a spool of filament, as used in many commercially-available weed trimmers, the preferred embodiment discloses a single, precut length of plastic filament  46 , rather than a continuous spool of filament, as the additional weight of the spool may adversely affect the battery life. The filament  46  may be comprised of a plastic, monofilament section having a shaped end  52 . The filament  46  is a replaceable, wear item. The housing  12  may optionally include a cylindrical cavity for storage of spare filament  46  pieces.  
         [0034]     Referring to  FIGS. 4 and 5 , in one embodiment, the shaped end  52  has a bulb  53  for mating with an insertion hole  50  in the hub  44 . The bulb  53  is designed to prevent the centrifugal force of the motor from ejecting the filament  46  when it is attached to the hub  44 . Hub  44  may include additional insertion hole  50  about its periphery for use of multiple filament sections  46 , or for spare insertion hole  50  in the event one becomes plugged.  
         [0035]     Referring to  FIGS. 6 and 7 , in another embodiment, the shaped end  52  includes a keyhole  55  configured to mate with a key  57  of the hub  44 . The key  57  and keyhole  55  are designed to prevent the centrifugal force of the motor  19  from ejecting the filament  46  when it is attached to the hub  44 .  
         [0036]     Referring next to  FIG. 8 , the weed and grass trimmer  10  is illustrated being inserted into an optional extension handle  36  so that the trimmer  10  may be used while a user is standing. Extension handle  36  has a socket  38  adapted to receive the cylindrical handle portion of housing  12 . Arrow  34  indicates the lateral direction of insertion and removal of the trimmer  10 . Socket  38  is appropriately sized for acceptance of a handle portion of housing  12  of the trimmer  10 . A key-way may be provided to prevent rotation while the trimmer  10  is locked into the socket  38 . A remote switch  40  at a top end of the extension handle  36  is interfaced with the weed trimmer  10  by way of plug  42  to transfer switch control to the opposite end of extension handle  36  when the trimmer  10  is placed into the extension handle  36 . When the trimmer  10  is inserted into the extension handle  36 , the safety-interlock switch  20  is engaged, so that the user can activate the motor  19  by pressing the remote switch  40  on the extension handle  36 . A wheel  37  may extend from a bottom end of the extension handle  36  to assist in supporting the trimmer  10  on a surface  39 .  
         [0037]     The safety-interlock switch  20  may be used to provide a test or “try me” feature while the trimmer  10  is inside a package  100 . Referring to  FIGS. 9 and 10 , in one embodiment, the package  100  comprises a transparent front blister portion  104  and a transparent back blister portion  102 . Front blister portion  104  and back blister portion  102  are manufactured using materials and methods well-known in the packaging art. Front and back blister portions  104 ,  102  are generally molded to conform to contours of the trimmer  10 . Front and back blister portions  104 ,  102  have sidewalls dimensioned so that when the trimmer  10  is placed between the front and back blister portions  102 ,  104 , the sidewalls are bonded by means known in the art to a generally flat outer perimeter flange-like portion  106  of package  100  such that the trimmer  10  is held securely within package  100  with minimal space to move. However, to facilitate the “try-me” feature, it is necessary that the part of package  100  containing the filament  46  be wide enough to accommodate the full range of motion of the filament  46 . A push-button switch opening  110  is positioned in front blister portion  104  to align with push-button switch  50  to permit a potential purchaser to press and actuate push-button switch  50 . A safety-interlock opening  112  is positioned in back blister portion  102  to align with safety-interlock switch  54  to permit a potential purchaser to press and actuate safety button  54 .  
         [0038]     In another embodiment (not shown), a clamshell package has a protrusion disposed so as to depress safety-interlocking switch and maintain the depressed position while the device is inside the packaging. The package allows a user to engage push-button switch in order to energize the motor, thereby causing the motor to turn the trim filament (or a paper representation of a filament) while enclosed in the packaging.  
         [0039]     In another embodiment (not shown), the package comprises a backing card and a transparent blister portion. Backing card and blister portion are manufactured using materials and methods well-known in the packaging art. Blister portion is generally molded to conform to the top contours of the trimmer and has sidewalls dimensioned so that when the trimmer is placed into the blister portion, the backing card can be laid flat across the blister portion and bonded by means known in the art to a generally flat outer perimeter flange-like portion of blister portion such that the trimmer is held securely within blister portion with minimal space to move. However, to facilitate the “try-me” feature, it is necessary that the part of blister portion containing the filament (or representation of the filament) be wide enough to accommodate the full range of motion of the filament. The portion of blister portion over push-button switch must be pliable enough to permit a potential purchaser to press blister portion down far enough to actuate push-button switch. Ideally, blister portion is manufactured of a shape-retaining material that will spring back to its original contours after it has been pressed down to actuate push-button switch.  
         [0040]     Since the trimmer is equipped with a safety-interlock switch that must be pressed in order to turn on the motor, a safety button block is enclosed in package between backing card and housing. Safety button block is preferably made of a relatively rigid, lightweight material, such as rigid plastic or foam, and is sized and shaped to fit securely between backing card and housing such that it holds the safety button in the depressed position while the trimmer is in package, thus allowing shoppers to turn on the motor by simply deforming the blister portion above push-button switch and pressing push-button switch. Once the trimmer is removed from the package, safety button block no longer presses against the safety interlock switch, and the trimmer is thus restored to full functionality.  
         [0041]     This “Try Me” feature is useful in attracting purchasers to the product by allowing potential buyers to feel the way in which the trimmer  10  operates without having to remove the trimmer  10  from the retail packaging  100 , thus encouraging buyers to purchase the trimmer  100 . Those skilled in the art will appreciate that the blister packages described above are only potential embodiments of such a “try-me” package  100 .  
         [0042]     According to the provisions of the patent statutes, we have explained the principle, preferred construction, and mode of operation of the present invention, and have illustrated and described what we now consider to represent its best embodiments. However, it should be understood that within the scope of the appended claims and the foregoing description, the present invention may be practiced otherwise than as specifically illustrated and described.