Patent Publication Number: US-2004056063-A1

Title: Hand-guided working tool, in particular a fuel-driven setting tool

Description:
BACKGROUND OF THE INVENTION  
       [0001] The present application relates to a hand-guided working tool, in particular a fuel-driven setting tool. Hand-guided working tools, such as fuel-driven setting tools, screw driving tools, electrical nail driving tools, for example, require electrical power as the main or ancillary energy for electrical consumers, control circuits, etc.  
       [0002] Fuel-driven setting tools that comprise a housing and a setting mechanism disposed therein, by which a fastener can be driven at a setting point in a substrate, when an operator triggers a setting operation using at least one switch, generally also comprise at least electronic components such as electronically controlled valves, ignition units, blowers, etc. These components and their control systems must be supplied with current, whereby mains independence is desirable. This energy is often provided by storage cells or batteries.  
       [0003] U.S. Pat. No. 4,403,722 discloses a gas-driven setting tool in which the mixture comprised of air and fuel gas situated in the combustion chamber prior to ignition is homogenized by an electrically driven blower. An NiCd storage battery is provided as the power supply for the blower drive and its control system.  
       [0004] A significant drawback of this type of power supply is the technology-related protracted charging time of the NiCd storage battery or alternatively storage batteries used. The charging process requires several hours even in a quick charge process. During this time, the working tool cannot be used unless the user carries a palette of exchange storage batteries.  
       SUMMARY OF THE INVENTION  
       [0005] The object of the present invention is the development of a hand-guided working tool of the that can be operated independent of a fixed location and that makes quick uptake and storage of electrical energy possible.  
       [0006] This object is achieved according to the invention by at least one high-performance capacitor being provided on a hand-guided working tool such as a fuel-driven setting tool, for example, for supplying the tool with power. By virtue of the connection of the capacitor to a charging port on the hand-guided working tool, the capacitor can be connected to an external power source and then charged in a few minutes. The tool-internal circuits or electrical consumers, which draw the required electrical energy via a controller circuit, if required, are connected to the capacitor on the discharge side  
       [0007] advantageously, the capacitor(s) has a capacity of 10 F to 10,000 F. In an electrical consumption of 10 Ws/setting, for example, and a setting rate of 500 sets per day, a capacitor of 1,200 F, for example, can be used, which, depending on losses and incomplete dischargeability, must be charged only 5 to 10 times per day for a very short time (˜1 minute).  
       [0008] By virtue of the fact that the capacitors are removably arranged in a receptacle on the setting tool they can also be easily exchanged, depending on the battery type, and replaced by new, charged capacitors without the working tool or the setting tool having to be connected to an external power source.  
       [0009] It is also advantageous, if the capacitors are part of an energy storage module in which a plurality of capacitors are interconnected and can be contacted there via an common external connections. When exchanging capacitors, only the energy storage module need be replaced and not a plurality of capacitors, which makes replacement simpler.  
       SUMMARY OF THE INVENTION 
     
    
    
     [0010] Further advantages and methods of the invention become apparent from the following description with reference to the drawings, wherein:  
     [0011]FIG. 1 shows a hand-guided setting tool in side view and partial cut-away, in accordance with the invention; and  
     [0012]FIG. 2 shows a wiring layout of the control circuit of the setting tool of FIG. 1. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0013] In FIG. 1 and FIG. 2, the hand-guided working tool  10  according to the invention is shown as a setting tool, which is driven using a combustible gas. The setting tool has a housing  1 , in which a setting mechanism  15  is arranged, by a fastener element  40  to be driven into a substrate (not shown herein). The fastener element  40  moves over the setting side end  18  of the driving piston and is driven into a substrate when the working tool  10  or setting tool is pressed against the substrate.  
     [0014] The setting mechanism  15  comprises a firing chamber or combustion chamber  23 , a piston guide  16 , in which a striking piston  17  is displaceably mounted, and a bolt guide  16 ′ in which a fastener element  40  is guided. The fastening element  40  moves via the setting end  18  of the striking piston  17  forward and can be driven into a substrate.  
     [0015] In the exemplary embodiment a firing chamber  23 , a blower  12  with a rotor  12 ′ or propeller and an ignition system  12 , such as a spark plug, are arranged in the combustion or firing chamber  23 . A turbulence is created in the burner or firing chamber using the blower  12  for mixing the fuel gas with air before an ignition spark is triggered by a control system  50  at the ignition unit  13  for igniting the fuel gas—air mixture.  
     [0016] The supply of the fuel gas in the combustion or firing chamber  23  occurs via a fuel feed line  22  and an electronically or mechanically controllable valve  21  from a fuel reservoir  20 . The setting operation is triggered only after operating a trigger or trigger switch  14  on the hand grip of the setting tool  10 . The switch can operate mechanically, electronically or even electromechanically.  
     [0017] In addition, further electrical or electromechanical switches can be provided on the setting tool that must be switched together or in different combinations to trigger a setting operation. These switches are a toggle-like, stacked switch or sensors that determine the nature of the substrate.  
     [0018] The power supply for the electrical consumers on the setting tool  10  such as the controller  50 , the blower  12 , the ignition unit  13 , the trigger switch  14  and, if applicable, the other switches, the valve(s)  21  and other electronic components is provided in the present setting tool  10  using a capacitor  31 . The capacitor  31  or the energy storage module  33  is arranged in a receptacle  28  on the setting tool  10  in the present exemplary embodiment and is arranged to be removable therefrom. The connection to the electrical electrical circuit in the setting tool  10  is made via contacts  27  on the energy storage module  33 /capacitor  31 , which co-operated with counter-contacts  29  in the receptacle  28 .  
     [0019] The distribution of the electrical energy from the capacitor  31  to the electrical consumers and the transmission of electrical control impulses is done via the controller unit  50 , which is arranged in a controller circuit  56  and over electrical input and control lines  51 ,  52 ,  53 ,  54 . Charging of the capacitor  31  is done using a charging port  30 , into which an electrical contact plug (not diagrammatically represented here) can be inserted. When this is done the plug contacts the electrical contacts  32  so that a charge current can flow over the electrical line  55  to the capacitor.  
     [0020] The fastening elements  40  are packaged in a magazine  41  in a magazine strip  42  that is disposed anterior on the setting tool  10 . The fastening elements  40  can, however, be inserted individually into the bolt guide  16 ′ by the user without such a magazine  41  being required.  
     [0021]FIG. 2 shows a circuit layout for the setting tool of FIG. 1. In this instance, one or several capacitors  31  (C 1 -C n ), which can be wired in series or in parallel, form the actual energy storage module  33 . The controllers R 1  and/or R 2  ( 56 ) can be integrated in this energy storage module  33 . R 1  controls the charging process of the capacitors  31  and provides overload protection. R 2  monitors the voltage of the capacitors  31  and controls them in a range, in which the control unit  50  and all connected electrical consumers, such as the dosing unit  21 , the display  57 , the actuators like the blower  12 , the switches  14 , the sensors  58 , the safety module  59  and the ignition unit  13  function safely and reliably. R 2  interrupts the current flow for the electrical consumers  21 ,  57 ,  12 ,  14 ,  58 ,  59 ,  13  in the event it falls below a defined minimal voltage. By picking up the capacitor voltage up stream of the controller R 2  it is possible to determine the charge status of the capacitors, which can be displayed, for example, on a screen  57 . As to the other legends, reference is made to the description of FIG. 1.  
     [0022] In summary, it must be noted that the invention is not limited to the embodiment represented. Hence, for example, a plurality of capacitors can be present. Similarly, the capacitor(s) can be arranged exchangeably in a special receptacle in the housing of the hand-guided working tool or setting tool.