Abstract:
A combustion-engined setting tool, including a housing ( 11 ), an axially displaceable piston guide ( 13 ) and a firing pin guide ( 12 ) provided on a side of the piston guide ( 13 ) facing in the direction opposite the setting direction and axially displaceable relative to the housing ( 11 ), damping element ( 20 ) supported against a stop ( 17 ) provided in the housing ( 11 ) and cooperating with the firing pin guide ( 12 ), and a locking device ( 30 ) having a locking position ( 28 ) in which it prevents a press-on force, which is generated upon the setting tool ( 10 ) being pressed against a construction component, from acting on the damping element ( 20 ), so that the damping element ( 20 ) remains inactive during a press-on process, and having a release position ( 29 ) in which the damping element ( 20 ) becomes active and is capable of absorbing recoil forces.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a setting tool including a housing, a piston guide located in the housing and axially displaceable relative thereto in a direction opposite a setting direction against a biasing force of a spring, a firing pin guide provided on a side of the piston guide facing in the direction opposite the setting direction and axially displaceable relative to the housing, and a damping element supported against a stop provided in the housing and cooperating with the firing pin guide for absorbing recoil forces during a setting process. 
     2. Description of the Prior Art 
     Setting tools of the type described above can be driven by solid, gaseous, or liquid fuels. In setting tools, the drive or setting piston is driven by combustion gases. The setting piston drives fastening elements in constructional components. 
     German Publication DE 195 44 105 A1 discloses a setting tool having a piston guide and a firing pin guide both arranged in the tool housing and axially displaceable relative to the housing against the force applied by a damping element supported in the housing. 
     The drawback of the known setting tool, in which the damping element is arranged in the press-on chain of the setting tool, consists in that the damping elements becomes compressed or upset to a certain degree already upon pressing of the setting tool against a constructional component. Therefore, the tool user senses, during the press-on step, a “light” stop, and the damping element cannot completely dampen any more recoil forces generated during a setting process. 
     Accordingly, an object to the present invention is to provide a setting tool of the type described above and in which the above-mentioned drawback is eliminated. 
     SUMMARY OF THE INVENTION 
     This and other objects of the present invention, which will become apparent hereinafter, are achieved by providing, in a setting tool, a locking device having a locking position in which it prevents a press-on force, which is generated upon the setting tool being pressed against a construction component, from acting on the damping element, whereby the damping element remains inactive during a press-on process, and having a release position to which the locking device is displaced upon actuation of a switch for actuating a setting process and in which the damping element becomes active and is capable of absorbing the recoil forces. 
     The particularity of the present invention consists in that a locking device is provided between the housing and the piston guide and/or the firing pin guide and which includes a plurality of locking elements which prevent transmission of a force to the damping element in the locking position of the locking device when the tool is pressed against a constructional component, and which allows a force to be transmitted to the damping element upon actuation of switching means that provides for displacement of the locking device to its release position. The locking device also permits to prevent the damping element from forming part of the press-on chain. This is because the locking device forms a bridge between the damping element and the movable piston and firing pin guides. After the locking device has been displaced in its release position, the entire damping path of the damping element becomes available for absorbing the recoil torque or the recoil pulse. Further, a user of the setting tool, upon pressing the tool against a constructional component, is able to detect a noticeable stop, which indicates to him that the tool has been completely pressed against the constructional component. 
     According to an advantageous embodiment of the present invention, the locking device has at least two locking elements which are brought in a stop relationship with each other in the locking position of the locking device and are displaced relative to each other in the release position of the locking device so that no bridging of the two elements exist, and the two elements can be displaced past each other. 
     Advantageously, one of the locking elements is formed as a stop which the other locking element that, e.g., is formed as a pivotal servo component, abuts in the locking position of the locking device. However, one of the locking elements can be translationally displaced. For bridging a larger displacement path, advantageously, a third locking element, which is formed as a stop securable to the housing, is provided. The first, second and third locking elements can form a continuous chain that would bridge the damping element in the locking position of the locking device. Advantageously, at least one locking element or locking member can be displaced, upon actuation of the setting process-actuating switch from its locking position, in which it abuts a stop, to its release position. 
     Advantageously, the switching means or the actuation switch is also connected with the ignition unit, so that the displacement of the locking device from its locking position to its release position takes place simultaneously with ignition of the propellant in the setting tool. 
     According to a further advantageous embodiment of the present invention, the locking device has a blocking member pivotally supported in the housing and formed as a pivotal lever, and a stop provided on the firing pin guide and which the blocking member engages in the locking position of the locking device. Instead of the firing pin guide, the stop can be provided on any other type of the ignition unit that is directly supported against the tool housing by a damping element. The blocking member engages the stop, which is provided on the firing pin guide or any other ignition unit, in its blocking position. 
     Advantageously, the blocking member is displaced from its blocking position behind the stop in its release position, in which it does not extend into the displacement path of the firing pin guide or the ignition unit, by an appropriate switch element, e.g., an actuation switch. For displacing the blocking member from its release position to its blocking position, there is provided a reset element that, e.g., can be arranged on the piston guide. 
     The reset element displaces the blocking member, with a suitable entrain member, from its release position to its blocking position when the piston guide returns to its initial position behind the stop on the firing pin guide or the ignition unit, upon lifting of the setting tool off the constructional component. 
     The novel features of the present invention, which are considered as characteristic for the invention, are set forth in the appended claims. The invention itself, however, both as to its construction and its mode of operation, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiments when read with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings show: 
         FIG. 1  a cross-sectional longitudinal view of the first embodiment of the setting tool according to the present invention in an inoperative position thereof, 
         FIG. 2  a cross-sectional view of along line II—II the setting tool shown in  FIG. 1 ; 
         FIG. 3  a cross-sectional longitudinal view of the setting tool shown in  FIG. 1  in its press-on position; 
         FIG. 4  a cross-sectional longitudinal view of the setting tool shown in  FIG. 2  in its press-on position and with an actuated actuation switch; 
         FIG. 5  a cross-sectional view of the setting tool shown in  FIG. 4  along line V—V in  FIG. 4 ; 
         FIG. 6  a cross-sectional longitudinal view of the settling tool shown in  FIG. 1  in its press-on condition after the ignition of the propellant charge; 
         FIG. 7  a cross-sectional longitudinal view of the second embodiment of the setting tool according to the present invention in an inoperative position thereof; 
         FIG. 7   a  a side view of a part of a locking device according to the present invention used in the setting tool shown in  FIG. 7 ; 
         FIG. 8  a cross-sectional longitudinal view of the setting tool shown in  FIG. 7  in its press-on position; 
         FIG. 9  a cross-sectional longitudinal view of the setting tool shown in  FIG. 7  in its press-on position with an actuated actuation switch; 
         FIG. 9   a  a side view of a part of the locking device used in the tool shown in  FIG. 9  in the actuated condition of the locking device; and 
         FIG. 10  a cross-sectional longitudinal view of the setting tool shown in  FIG. 7  in its press-on condition after the ignition of the propellant charge. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A combustion-engined setting tool  10  according to the present invention, a first embodiment of which is shown in  FIGS. 1-6 , includes a one-part or multi-part housing  11  and a piston guide  13  which is arranged in the housing  11 . A piston  15  is displaceably arranged in a hollow chamber  14  of the piston guide  13 . The piston  15  is driven by a propellant or by products of its reaction such as, e.g., combustion gases, etc. . . . A handle  21 , which is provided on the housing  11 , carries an actuation switch  16  with which a user of the setting tool  10  initiates a setting process. In the embodiment shown in  FIGS. 1-6 , the piston guide  13  is displaceably supported in the sleeve-shaped housing  11 . The piston guide  13  is resiliently supported, by a spring  19 , against a firing pin guide  12  which is likewise arranged in the sleeve-shaped housing  11 . The firing pin guide  12  is located farther in the interior of the housing  11  and is supported against a damping element  20  which is supported against a stop  17  provided on an inner wall of the housing  11 . The damping element  20  is formed as an elastic annular ring. Other designs of the damping element can also be used, e.g., the damping element can be formed as a hydraulic shock absorber that can also be combined with a spring element. 
     The spring  19  can be formed e.g., as a compression spring that pushes the piston guide  13  out of the housing  11  to a stop when the setting tool  10  is not pressed against a constructional component. The extended position of the piston guide  13  is shown in  FIG. 1. A  setting process with the setting tool  10  is only then possible when the setting tool is pressed against a constructional component with a bolt guide  24  that is located downstream of the piston guide  13  in the setting direction. It should be pointed out that the bolt guide can also be made displaceable relative to the piston guide. 
     On the piston guide  13 , there is provided a cartridge chamber  18  in which a propellant can be received (not shown in the drawing). The propellant can be provided in form of cartridges, pellets and the like which can be located in a magazine strip. 
     The setting tool  10  further includes a locking device  30  that mechanically bridges over the damping element  20  with the constructional component during the press-on process so that the damping element is not subjected to a load. However, upon initiation of a setting process with the actuation switch  16 , the bridge-over is lifted so that the damping element  20  is able to absorb the recoil force. The structure and operation of the locking device  30  will be explained in more detail further below. 
     The firing pin guide  12  has a hollow chamber  35  which is adjoined, in a direction opposite the setting direction, by a channel  36  in which a firing pin  22  is displaceably arranged. The channel  36  opens in the interior of the housing  11 . When the setting tool  10  is pressed against a constructional component, the firing pin  22  acts, through a conical opening  37  facing the cartridge chamber  18 , on a propellant located therein. In the rear wall of the housing  11 , there is supported a locking element  33  of the device  30  and which is formed as an elongate pin. The locking element  33  is arranged coaxially with the channel  36 . The locking element  33  forms a housing-side stop  43  for the firing pin  22  that carries, in its front region, a further locking element  32  of the locking device  30 . The locking element  32  is formed as a blocking member  42 . The firing pin  22  is fixedly connected with the locking element  32  and is pivotally guided therewith in the firing pin guide  12 . A spring  23  biases the firing pin  22  in the direction toward the opening  37  so that the firing pin  22  and the locking element  32  reach the opening  37  and are located shortly before it (the locking element  32 ) in the non-operative position of the setting tool  10  (shown in FIGS.  1 - 2 ). 
     A further locking element  31  is provided on the piston guide  13 . The locking element  31  also forms part of the locking device  30  and forms a stop  41  for the locking element  32  (the blocking member  42 ). The locking element  31  is formed as an elongate pin. In the non-operative or initial position of the setting tool  10  shown in  FIGS. 1-2 , the pin-shaped locking element  31 , together with the stop  41 , extends through an opening  44  into the hollow chamber  35 , with the stop  41  being located in front of the blocking member  42 . When the setting tool  10  is pressed against a constructional component (not shown), the piston guide  13  is displaced against the biasing force of the spring  19  in the direction  51  into the interior of the housing  11 , and the stop  41  presses the blocking member  42  inward, whereby the firing pin  22  is displaced in the firing pin guide  12  to its rearward position, as shown in FIG.  3 . In the position shown in  FIG. 3 , the cartridge chamber  18  abuts the firing pin guide  12  and is located in front of the opening  37 . Thus, upon the completion of the press-on process, the piston guide  13  is supported opposite the firing pin  22  by the locking elements  31 ,  32  and through the locking elements  31 ,  32  and the firing pin  22  against the stop  43  formed by the locking element  33  and, thereby, against the housing  11 . 
       FIGS. 4-5  show the position of the setting tool  10  upon actuation of the switch  16  that actuate switching means  26  which includes several levers and members. As it is particularly shown in  FIG. 5 , a switching lever  27  of the switching means  26  pivots the blocking member  42  away from the stop  41  so that the locking device  30  is displaced from its locking position  28  (shown with dash lines) to its release position  29 . Upon the displacement of the locking device  30  into its release position, the firing pin  22 , which is not retained any more in its rearward position by the stop  41 , is advanced by the biasing force of the spring  23  forward, acting on a propellant (not shown), igniting the same, as shown in FIG.  6 . The released gases  25 , which are produced as a result of the combustion of the propellant, displace the drive piston in the setting direction  50 . The front end of the drive piston impacts a fastening element (not shown) located in the bolt guide  24 , driving the fastening element in a constructional component. The recoil force displaces the firing pin guide  12  and the piston guide  13  in the direction  51  into the interior of the housing  11 , with the recoil pulls being damped by the damping element  20  which is not locked any more (see FIG.  6 ). 
       FIGS. 7-10  show a second embodiment of a setting tool according to the present invention. The setting tool  10  according to the second embodiment differs from the setting tool described with reference to  FIGS. 1-6  by a different design of the firing pin guide  12 , together with the firing pin  22 , and of the locking device  30 . The construction of the firing pin guide  12  and of the locking device  30  will be discussed in detail further below. The technical details of this embodiment, which corresponds to those of the setting tool described with reference to  FIGS. 1-6 , will be discussed by reference to the above-mentioned description of the first embodiment of the setting tool. 
     The firing pin guide  12  of the setting tool  10  according to the second embodiment differs from that of the setting tool according to the first embodiment in that the channel  36  has its rear end, i.e., the end facing the damping element  20 , closed. 
     Further, a locking element  31  of the locking device  30 , which forms a stop  141 , is provided in the lower region of the firing pin guide  12  adjacent to the handle  21 . The locking element  31  cooperates with the locking element  32  of the locking device  30  and which is formed as a lever-shaped blocking member  142 . The blocking member  142  is arranged in the hosing  11  and is pivotally secured, at its housing-side end, on an axle  38 . The blocking member  142  is engaged by a spring  39  that biases the blocking member  142  in direction  49 , i.e., in the direction of its release position  29  (see FIG.  9 ). On the blocking member  142 , there is provided a blocking nose  144  that engages in the locking position  28  of the locking device  30 , the stop  141  which is provided on the firing pin guide  12 . A reset element  34 , which is provided on the piston guide  13 , cooperates with the blocking member  142  and, in particular, with an inclination surface  45  provided on the blocking member  142 . A precise function of the reset element  34  will be discussed further below. 
     Actuation means  26 , which is actuated by the actuation switch  16 , includes, in the embodiment of the setting tool shown in  FIGS. 7-10 , a lever  27  that, as shown in  FIG. 7 , supports the blocking member  142  in its blocking position  28 , retaining the blocking member  142  in this position against the biasing force of the spring  39  until the actuation switch  16  is actuated. 
     In the embodiment of the setting tool  10  shown in  FIGS. 7-10 , the damping element  20  is formed as a solid, massive elastic element that is supported against a stop  17  provided in the housing  11 . At its end opposite the stop  17 , the damping element  20  abuts a rear surface of the firing pin guide  12 . 
     As it has already been described above, in the locking position of the locking device  30 , which is shown in  FIG. 7 , the blocking nose  144  of the locking element  32  or the blocking member  142  engages the stop  141  provided on the firing pin guide  12 . When the setting tool  10  is pressed against a constructional component, the piston guide  13  is displaced in direction  51  into the interior of the housing  11 , compressing the spring  19 , The pin, which forms the stop  41 , is displaced through the opening  44 , which is formed in the firing pin guide  12 , into the hollow chamber  35 , displacing the blocking member  42 , together with the firing pin  22  that is fixedly connected with the blocking member  42 , to their rear position which is shown in FIG.  9 . The displacement of the firing pin  22  rearwardly results in compression and preloading of the spring  23 . As shown as the cartridge chamber  18  abuts the front end of the firing pin guide  12 , further pressing of the setting of the setting tool  10  against the constructional component is not any more possible. This is because the locking device  30 , which occupies its locking position  28 , prevents the displacement rearwardly of the piston guide  13  and the firing pin guide  12  and, in particular, prevents the firing pin guide  12  from compressing the damping element  20 . 
     Further, when the setting tool  10  is pressed against a constructional component, the reset element  34  is also displaced with the piston guide  13  in the rearward direction  51 , as shown in FIG.  8 . Upon being displaced in the direction  51 , the reset element  34  moves away from the inclination surface  45  that is formed on a cam provided on the blocking member  142 . The displacement of the reset element  34  away from the inclination surface  45  allows for the pivotal movement of the blocking member  142 . 
     Upon actuation of the switch  16 , the switching means  26  is actuated, and the switching lever  27  pivots away from its support position beneath the front end of the blocking member  142 , and the blocking member  142  pivots, under the biasing force of the spring  39 , from its locking position  28  (shown in  FIG. 7 ) to its release position  29  (shown in FIG.  9 ). Upon actuation of the switch  16 , simultaneously, the switching means  26  pivots the blocking member  42 , which is provided on the firing pin  22 , a certain amount. As a result, the firing pin  22  is displaced in the setting direction  50  under the action of the spring  23 , igniting propellant (not shown) located in the cartridge chamber  18 , as shown in  FIG. 10. A  recoil pulse causes displacement of the piston guide  13  and the firing pin guide  12  in the direction  51  and against the damping element  20 . The damping element  20  damps the recoil pulse, preventing the recoil force from acting, at least to a substantial degree, on the user of the setting tool  10 . 
     When the setting tool  10  is lifted, after completion of the setting process, off the constructional component, the damping element  20  returns to its initial position, displacing the firing pin guide to its initial position. The piston guide  13  likewise returns into its initial position under the action of the spring  19 . The reset element  34  is displaced in the setting direction  50 , together with the piston guide  13 , and moves along the inclination surface  45  provided on the blocking member  142 , returning the blocking member  142  to its locking position  28  shown in FIG.  7 . 
     Though the present invention was shown and described with references to the preferred embodiments such are merely illustrative of the present invention and are not to be construed as a limitation thereof and various modifications of the present invention will be apparent to those skilled in the art. It is, therefore, not intended that the present invention be limited to the disclosed embodiments or details thereof, and the present invention includes all variations and/or alternative embodiments within the spirit and scope of the present invention as defined by the appended claims.