Abstract:
A switch mechanism that can be attached to a conventional cordless power tool. The switch is attached to the power pack on the cordless tool and when turned on starts the tool thereby eliminating the need to keep constant pressure on the conventional pressure switch associated with such tools.

Description:
BACKGROUND OF THE INVENTION 
   This invention relates, in general, to switches, and, in particular, to switches to allow remote operation of a cordless tool. 
   DESCRIPTION OF THE PRIOR ART 
   In the prior art various types of devices have been proposed. For example, U.S. Pat. No. 3,767,876 to Batson discloses a remote switch for a power tool such as a router. 
   U.S. Pat. No. 3,602,728 to Carpenter discloses a remote operated tool which uses a coil to turn on the tool. 
   U.S. Pat. No. 5,681,214 to Kleider discloses a hand power tool with a remote handle to operate the tool. 
   U.S. Pat. No. 4,935,733 to Munekata discloses a remote control receiver which responds to a coded receiver from a transmitter to turn a device on and off. 
   U.S. Pat. No. 4,707,921 to Meyer discloses an exterior handle for a tool that removable attaches to the handle for remote control of the tool. 
   The present invention is designed to be used in high risk environments to allow mechanical tasks to be performed without creating additional risks to humans. The present invention, for example, would allow cordless tools to be used by law enforcement robots at the scene of a high risk entry. A robotic device could be equipped with the present invention and the cordless tool could be operated by a remote operator of the robot. The remote operator, through the use of the switch of the present invention, could operate the cordless tool, which normally has a depression switch which must be constantly depressed to operate the tool, without constantly depressing the conventional switch on the cordless tool. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to a switch mechanism that can be attached to a conventional cordless power tool. The switch is attached to the power pack on the cordless tool and when turned on starts the tool thereby eliminating the need to keep constant pressure on the conventional pressure switch associated with such tools. 
   It is an object of the present invention to provide a new and improved switch for cordless power tools. 
   It is an object of the present invention to provide a new and improved switch for cordless power tools that can be added to any cordless power tool. 
   It is an object of the present invention to provide a new and improved switch for cordless power tools that can be easily and quickly added to any power tool. 
   These and other objects and advantages of the present invention will be fully apparent from the following description, when taken in connection with the annexed drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of the present invention attached to a cordless drill. 
       FIG. 2  is an electrical schematic view of the wiring of the present invention. 
       FIG. 3  is an electrical schematic view of another embodiment of the wiring of the present invention. 
       FIG. 4  is an electrical schematic view of another embodiment of the wiring of the present invention. 
       FIG. 5  is a partial view showing the electrical connection between the switch of the present invention and the conventional battery pack. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to the drawings in greater detail,  FIG. 1  shows the present invention  1  attached to a conventional cordless power tool  2 , in this case a cordless drill, with a drill bit  4  attached in the conventional manner. It should be noted that the drill in  FIG. 1  is used merely for illustration purposes, and other cordless power tools could be used with the present invention. The drill  2  has a conventional trigger switch  3  and a battery pack  5  to power the tool. The switch  3  is a conventional pressure switch used on cordless tools which must be held depressed by the user in order to operate the cordless tool  2 . The add-on device  6  of the present invention is secured to the battery pack  5  and has a switch  7  which, when operated, will bypass the conventional switch  3  to operate the cordless tool  2 . The preferred method of securing the device  6  to the tool  2  is to use hook and loop fastener straps  19 , although other fasteners could be used without departing from the scope of the invention. 
   The device  6  is electrically connected to the tool  2  by an electrical cord  20  which has a plug  8  on one end (see  FIG. 5 ). The plug  8  is connected to a socket  13 , to electrically connect the device  6  to the internal wiring of the tool  2  through the housing of the tool  2  just above the battery pack  5 . 
   The switch  7 , as shown in the wiring shown in  FIGS. 2–4  allows the switch  7  to be activated and eliminates the need to keep the conventional switch  3  depressed in order to operate the tool  2 . This would allow the cordless tool to be secured to, and operated by, a robotic device which would not be able to maintain the conventional switch  3  depressed in order to operate the tool  2 . 
   As shown in  FIG. 2 , the present invention is electrically connected by means of a plug  8  and a socket  13  to the conventional internal wiring of the tool  2 . The preferred plug  8  and socket  13  is a BNC plug and socket, however, any connector that will accomplish the same results can be used without departing from the scope of the invention. Normally, when operating the tool  2 , the user presses the pressure switch  3  and holds the switch to operate the tool. When the switch  3  is released, the tool stops. Also, this type of tool usually incorporates a reverse switch, so the direction the cordless drill rotates can be reversed. For example, if the user wants to remove a screw (as opposed to installing a screw) he/she can turn the reverse switch and then press the switch  3  to remove a screw. Since the reverse switch is conventional, it has not been shown in the drawing for clarity. Also, the switch of the present invention is not reversible. 
   When the switch  7  is moved to the “on” position, electricity will flow from the battery  5  through the connector  8 ,  13  to the motor  10  bypassing the conventional switch  3 . Since the switch  7  is not a pressure switch, the motor  10  and the tool will operate without holding the switch in a depressed condition. This will allow a robot operator to operate the tool in a more convenient and simplified manner. The diode  14  prevents current flowing back to the battery  5  when the normal switch  3  is used. This allows the tool  2  to be used in the normal manner, i.e. by depressing and keeping the switch  3  depressed, or by operating the switch  7  of the present invention. 
   The circuit shown in  FIG. 3  is similar to the circuit of  FIG. 2  and similar elements are used with a “prime” designation in  FIG. 3 . In the  FIG. 3  circuit, an additional switch  16  is interposed between the connector  13 ′ and plug  8 ′ and switch  7 . The switch  16  is normally closed which allows pressure switch  3 ′ to control the motor  10 ′. In order to insert switch  7 ′ into the circuit and disconnect switch  3 ′ from the circuit, plug  8 ′ is inserted into connector  13 ′. When this happens, plug  8 ′ opens switch  16  which disconnects switch  3 ′ from the circuit. Power from the battery now runs through switch  7 ′, which is an on/off switch, and the the motor  10 ′ will not operate unless switch  7 ′ is closed. Switch  16  is similar to the switch used on stereos to plug in headphones. When the headphones are plugged in, the normal speakers are disconnected from the circuit, and sound comes only through the headphones. 
   The circuit shown in  FIG. 4  is similar to the circuits of  FIGS. 1 and 2  and similar elements are used with a “double prime” designation in  FIG. 4 . In the  FIG. 4  circuit, the switch  7 ″ is placed in parallel with the switch  3 ″ so either switch  3 ″ or  7 ″ can be used to operate the tool. 
   Although the WDS Switch and the method of using the same according to the present invention has been described in the foregoing specification with considerable details, it is to be understood that modifications may be made to the invention which do not exceed the scope of the appended claims and modified forms of the present invention done by others skilled in the art to which the invention pertains will be considered infringements of this invention when those modified forms fall within the claimed scope of this invention.