Abstract:
A setting tool includes a housing ( 11 ), a bolt guide ( 12 ) axially displaceable relative to the housing ( 11 ), a safety sleeve ( 20 ) at least regionwise surrounding the bolt guide ( 12 ) and having at least two shell parts ( 21, 22 ) formed of tubular sections, and a clamp member ( 23 ) at least regionwise encompassing the two shell parts ( 21, 22 ) for forming the safety sleeve ( 20 ).

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a setting tool including a housing, a bolt guide axially displaceable relative to the housing, and a safety sleeve at least regionwise surrounding the housing and having at least two shell parts formed of tubular sections.  
         [0003]     2. Description of the Prior Art  
         [0004]     Setting tools of the type described above can be driven with solid, gaseous, or liquid fuels or with compressed air. In combustion energy-driven tools, the setting or drive piston is driven by high pressure combustion gases. The setting or drive piston drives fastening elements into a constructional component.  
         [0005]     For safety reason, in setting tools driven with high-pressure gases, usually, there is provided safety means that prevents actuation of the setting tool when the setting tool is inadvertently pressed against an object. This safety means includes usually a safety sleeve that surrounds the bolt guide and is axially displaceable relative thereto. When the safety sleeve is manually displaced in a direction opposite the setting direction, the safety sleeve prevents actuation of the setting tool.  
         [0006]     German Publication DE 100 48 311 A1 discloses a setting tool in which a press-on filler and a protection sleeve surround the bolt guide of the tool. The press-on filler or sleeve and the protection sleeve project beyond the bolt guide in the setting direction and are displaced in a press-on position in which actuation of the setting tool becomes possible, when the setting tool is pressed against a constructional component. When the protection sleeve is manually displaced in the direction opposite the setting direction, the protection sleeve prevents actuation of the setting tool.  
         [0007]     The drawback of the setting tool of DE 100 48 311 A1 consists in that the relatively thin bolt guide is subjected to an extreme load when inadvertently several nails are placed upon one another or when the setting tool strikes inadvertently a constructional component.  
         [0008]     In a setting tool DX 351 M&amp;E of Hilti Aktiengesellschaft (the assignee herein), catalog, France, 2002, p. 160, a two-part safety sleeve is arranged about the bolt guide, with the bolt guide projecting beyond the safety sleeve in the setting direction. The safety sleeve has two shell parts connected with each other by four threaded elements. The manufacturing of this safety sleeve is rather expensive because of a need in screwing operations in four connecting locations.  
         [0009]     Accordingly, an object of the present invention is to provide a setting tool with a safety sleeve in which the drawbacks of the prior art setting tools or safety means are eliminated.  
       SUMMARY OF THE INVENTION  
       [0010]     This and other objects of the present invention, which will become apparent hereinafter, are achieved according to the present intention of forming the shell parts of tubular sections and by providing a clamp element that at least regionwise surrounds the two shell parts for forming the safety sleeve. The provision of the clamp element saves time during assembly of the safety sleeve as the two shell parts are simply arranged about the bolt guide, and the clamp element is pushed over or is clipped over the two shell parts to connect the two shell parts together. The present invention permits to form the setting tool, in the region of the front end of the bolt guide, very slim, which permits to set fastening elements in very narrow cavities.  
         [0011]     Advantageously, the bolt guide is provided at its end facing in the setting direction with a annular cylindrical thickening that protects the safety sleeve from wear. The thickening also increases the service life of the bolt guide. In addition, the thickening prevents the safety sleeve from being lost.  
         [0012]     Advantageously, the clamp element is formed as a tubular body the tubular wall of which is provided with a slot extending parallel to the longitudinal axis of the tubular body. The clamp element has, at least in a condition when it surrounds or is pushed over the two shell parts, an outer diameter corresponding to the outer diameter of the cylindrical thickening of the bolt guide. With the outer diameter of the clamp element corresponding to the outer diameter of the bolt guide thickening, the safety sleeve can be flush locked with the front end (annular thickening) of the bolt guide. The slot permits to bend the clamp element off to facilitate its placement on the shell parts.  
         [0013]     According to an advantageous embodiment of the present invention, one of the shell parts is provided at one of its end with a projecting element that can be formed as a funnel-shaped element with the funnel opening lying in the direction opposite the setting direction. This element, together with a further transfer member, serve for blocking the actuation switch or a setting process when the setting tool is not pressed against a constructional component and the safety sleeve is manually displaced rearwardly.  
         [0014]     It is further advantageous when this projecting element has a recess. In this recess, a complementary projecting element, e.g., a funnel section which is provided on the other of the shell parts, can engage, locking the projecting element of the first shell part. With two projecting elements of which one is provided with a recess, during the assembly of the setting tool, the bolt guide with its thickened front end is pushed through the recess, with subsequent assembly of the shell parts to form the safety sleeve.  
         [0015]     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:  
       [0016]     The drawings show:  
         [0017]      FIG. 1 a  side view of a setting tool according to the present invention;  
         [0018]      FIG. 2 a  longitudinal cross-sectional view along line II-II in  FIG. 3  of the bolt guide of the setting tool shown in  FIG. 1 ; and  
         [0019]      FIG. 3  an exploded view of the bolt guide of the setting tool shown in  FIG. 1 .  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0020]     A powder charge-operated setting tool  10  according to the present invention, which is shown in  FIGS. 1-3 , includes a one-part or multi-part housing  11  in which a piston guide is arranged, and a drive piston (not shown) for fastening elements which is displaceable in the piston guide. For initiating a setting process, an actuation switch  17  is provided on a handle  16  of the setting tool  10 . In front of the piston guide, in the setting direction  30  of the setting tool  10 , a bolt guide  12  is arranged. The bolt guide  12  is surrounded regionwise by a safety sleeve  20 . At the end of the bolt guide  12  adjacent to the piston guide, there is provided connection means  15 , such as, e.g., a helical thread, which connects the bolt guide  12  coaxially with the piston guide. At the end of the bolt guide  12  facing in the setting direction  30 , there is provided an annular thickening  13  such as, e.g., an annular bead an outer surface of which is flush locked with an outer surface of a clamp element  23 , which is formed as an annular body, of the safety sleeve  20 . The clamp element  23  has a slot  24  that extends parallel to its longitudinal axis  29  and that insures that the clamp element can be bent off. The safety sleeve  20 , which is shown in detail in  FIGS. 2-3 , has first and second shell parts  21  and  22 . Both shell parts  21 ,  22  are formed, at least regionwise, as a half-shell of a tube and surround the front portion of the bolt guide  12 . The thickening  13  of the bolt guide  12  protects the front end of the shell parts  21  and  22  from stripping and other damages. The clamp element  23 , which is pushed over the shell parts  21 ,  22  or is clipped thereover during the assembly of the setting tool  10 , connects the two shell parts  21 ,  22  with each other.  
         [0021]     At the rear, in the settling direction  30 , end of the first shell part  21 , there is provided a funnel-shaped member  25  having a stop surface  28  facing in the direction opposite to the setting direction  30 . The member  25  has a recess  26  through which the front end of the bolt guide  12  with the thickening  13  passes during the assembly of the setting tool  10 . During the assembly of the setting tool  10 , a complementary projecting element  27  of the second shell part  22  is received in the recess  26 . In this way, in the assembled condition of the safety sleeve  20 , at its end adjacent to the piston guide, there is provided a funnel-shaped element  25 ,  27  that completely surrounds the bolt guide  12 . The recess  26 , in which the projecting element  27  of the second shell part  22  is received, provides for correct alignment of the shell part  22 . The funnel-shaped element  25 ,  27  can be engaged with one or more spring elements (not shown) which bias the safety sleeve  20  in the setting direction  30 . The bolt guide  12  is provided with a stop  14  which is spaced from the end of the bolt guide  12  facing in the setting direction  30  and is arranged opposite the funnel-shaped element  25 ,  27 . The stop  14  limits the displacement path of the safety sleeve  20  relative to the bolt guide  12 . The safety sleeve  20  prevents an inadvertent free running or displacement of the setting tool  10  when the setting tool is not pressed against a constructional component, and only the safety sleeve  20  is pulled manually in the direction opposite the setting direction  30 .  
         [0022]     The safety sleeve  20  functions as follows. The setting tool  10  is provided with a stop surface  40 . When the safety sleeve  20  is unexpectedly pushed in the direction opposite the setting direction  30 , the safety sleeve  20  is displaced over the bolt guide  12  in the direction opposite the setting direction  30  until it abuts the stop  14  on the bolt guide  12 . Then, with the setting tool  10  being pressed against a constructional component, the safety sleeve  20  is displaced together with the bolt guide  12 . A premature actuation of the setting tool  10  is prevented by the fact that the safety sleeve  20  engages the stop surface  40  of the setting tool  10  before the setting tool  10  reaches its ignition position. Further press-on displacement as a result of the safety sleeve  20  being pressed back is not any more possible, which reliably prevents the free running.  
         [0023]     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.