Abstract:
A setting tool for driving fastening elements in a constructional component includes a piston guide ( 11 ) adjoining the tool combustion chamber ( 16 ), a setting piston ( 20 ) arranged in the hollow space ( 12 ) of the piston guide ( 12 ) for an axial displacement therein, a piston stopping element ( 30 ) for the setting piston ( 20 ) and arranged in an end region ( 17 ) of the hollow space ( 12 ) remote from the combustion chamber ( 16 ), and a device ( 40 ) for axially displacing the piston stopping element ( 30 ) in the hollow space ( 12 ).

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a setting tool for driving fastening elements in a constructional component and including a combustion chamber, a piston guide adjoining the combustion chamber, a setting piston arranged in the hollow space of the piston guide for an axial displacement therein, and a piston stopping element for the setting piston and arranged in an end region of the hollow space remote from the combustion chamber.  
         [0003]     2. Description of the Prior Art  
         [0004]     Setting tools of the type discussed above can be driven using solid, gaseous, or liquid fuels, or a compressed air.  
         [0005]     In the above-described setting tools in which a piston drives a fastening element in a constructional component, generally, pressure is applied to the piston at the piston end opposite the fastening element. In the combustion-engined setting tools, the piston is driven, e.g., by combustion gases. Under the pressure acting on the piston, the piston is accelerated in the direction of the fastening element, impacts the fastening element, and drives it in the constructional component.  
         [0006]     Sometimes it is desirable that the fastening element is not always driven in a constructional component to the same depth. When the constructional component is soft, e.g., a fastening element would be driven, under the same condition, deeper than when it would have been driven in a hard component. This can result in the damage of the material into which the fastening element is driven in.  
         [0007]     In a setting tool Hilti GX100 of the assignee herein, a setting piston is guided in a piston guide, and a bolt guide adjoins the piston guide in the driving-in direction. At the end of the piston guide adjacent to the bolt guide, there is provided a buffer element for the setting piston that limits the displacement of the piston in the driving-in direction. On the bolt guide, a press-on sleeve is provided that can be displaced along the bolt guide between two positions, defining two stages. The press-on sleeve permits to get a maximum drive-in depth.  
         [0008]     The drawback of the known setting tool consists in that with the press-on sleeve being mounted on the bolt guide, the outer dimensions of the setting tool are increased, which constrains the to-be-handled profiles.  
         [0009]     Accordingly, an object of the present invention is to provide a setting tool of the type described above in which the foregoing drawback is eliminated.  
         [0010]     Another object of the present invention is a setting tool of the type described above and in which adjustment of the drive-in depth can be effected to a most possible extent.  
       SUMMARY OF THE INVENTION  
       [0011]     These and other objects of the present invention, which will become apparent hereinafter, are achieved by providing in the setting tool a device for axially displacing the piston stopping element in the hollow space of the guide spindle.  
         [0012]     The displacing device permits to continuously or stepwise adjust the position of the piston stopping element or the support with the piston stopping element in the direction of the longitudinal axis of the piston guide. With the device, a maximum possible stroke of the setting piston and, thereby, a maximum possible drive-in depth can be changed, without increasing, in the mouth region of the setting tool, the dimensions of the bolt guide by additional elements or components. The piston stopping element can be formed, e.g., as a buffer element from rubber, or from metal.  
         [0013]     Advantageously, there is provided a support for the piston stopping-element which is adjustably arranged in the end region of the hollow space of the piston guide. The support offers a constructively easy solution for replacing the attached thereto, piston stopping element.  
         [0014]     Advantageously, the support and/or the piston stopping element are rotatably supported about the longitudinal axis of the piston guide. This permits to effect an axial adjustment by rotating the support and/or the piston stopping element.  
         [0015]     It is advantageous when the displacement device includes first and second support surfaces provided on the support for the piston stopping element and ramp surfaces provided between the first and second support surfaces, and spaced first and second counter-support surfaces provided on an end surface of the piston guide and counter-ramp surfaces provided between the first and second counter-support surfaces. The axial distance between the end wall of the piston guide and the support can be adjusted by appropriate positioning of the support and counter-support surfaces. Advantageously, the displacing device displaces the piston stopping element back and forth in the hollow space of the piston guide between two axially spaced positions.  
         [0016]     The displacing device can include at least one actuation member with which it can be manually actuated. The actuation member can be formed, e.g., as a lever which is fixedly connected with a bearing section of the support.  
         [0017]     It is advantageous when in the first position of the piston stopping member, the first support surface abuts the second counter-support surface, and the second support surfaces abuts the first counter-support surfaces, and in the second position of the piston stopping member, the second support surfaces abuts the second counter-support surfaces.  
         [0018]     The first and second support surfaces and/or the first and second counter-support surfaces are axially spaced from each other, respectively, and are separated from each other with ramp surfaces and counter-ramp surfaces. Upon rotation, the opposite and sliding over each other ramp surfaces and counter-ramp surfaces cause an axial translational movement of the support and/or of the piston stopping element. In this way, the two axially spaced positions of the support and/or of the piston stopping element can be defined in a technically simple manner.  
         [0019]     Advantageously, the first and second support surfaces and counter-support surfaces extend transverse to a longitudinal axis of the piston guide, i.e., they extend, during the setting process, parallel to the constructional component. Thereby, when the setting piston strikes the piston stopping member, only reaction forces acting in the direction of the tool axis or the longitudinal axis of the piston guide are generated. Rotation of the support does not take place during the setting process.  
         [0020]     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 embodiment, when read with reference to the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]     The drawings show:  
         [0022]      FIG. 1 a  longitudinal cross-sectional view of a setting tool according to the present invention with a piston stopping device in a first position thereof;  
         [0023]      FIG. 2 a  perspective, partially cross-sectional view of a detail of the setting tool shown in  FIG. 1 ;  
         [0024]      FIG. 3 a  perspective view of a further detail of a setting tool shown in  FIG. 1 ;  
         [0025]      FIG. 4 a  longitudinal cross-sectional view of the setting tool shown in  FIG. 1  with the stopping device in an intermediate position thereof; and  
         [0026]      FIG. 5 a  longitudinal cross-sectional view of the setting tool shown in  FIG. 1  with the piston stopping device in a second position thereof. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0027]     A hand-held, combustion-engined, setting tool  10  according to the present invention, which is shown in  FIGS. 1 through 5 , has a combustion chamber  16  and a piston guide  11  that adjoins the combustion chamber  16 . A setting piston  20  is displaceably arranged in the hollow space  12  of the piston guide  11 . The setting piston  20  is driven by combustion gases which are produced upon combustion of a fuel in the combustion  16 . A bolt guide  24  adjoins the piston guide  11  at its end remote from the combustion chamber  16 . The bolt guide  24  extends coaxially with the piston guide  11 . In the end region  17  of the hollow space  12  of the piston guide  11  adjacent to the bolt guide  24 , there is arranged a piston stopping element  30 . The piston stopping element  30  is supported on a support  31  which is rotatably supported, with its bearing section  37 , in the opening  25  of the piston guide  11  and/or in an opening  26  of the bolt guide  24  that adjoins the piston guide opening  25 . The bearing section  37  is supported for an axial displacement along a longitudinal axis  19  of the piston guide  11 . At a side thereof adjacent to the setting piston  20 , the piston stopping element  30  is provided with a stop surface  32  for the setting piston  20 . The setting piston  20  has a piston body  23  and piston head  21  which is provided at the end of the setting piston  20  adjacent to the combustion chamber  16  and is fixedly connected with the piston body  23 . The piston head  21  has a counter-stop surface  22  facing in the direction of the piston stopping element  30  that can abut the stop surface  32  of the piston stopping element  30  upon displacement in the direction of the piston stopping element  30 . Thus, the piston stopping element limit the maximal stroke of the setting piston  20 .  
         [0028]     With a device which is generally designated with a reference numeral  40 , the piston stopping element  30  and the support  31  are displaced from a first position  41  which is shown in  FIG. 1  and in which the maximum possible stroke of the piston  20  is the greatest, to a second position  42  which is shown in  FIG. 5  and in which the maximum possible stroke of the setting piston  20  is the smallest. Thus, the device  40  permits to adjust, in a simple manner, a maximum possible drive-in depth. The displacing device  40  includes first support surfaces  34  and second support surfaces  35  which are provided on a side of the support  31  adjacent to the bolt guide  24 . The arrangement of support surfaces  34  and  35  can be seen in  FIG. 3 . The second support surfaces  35  project beyond the firs support surfaces  34  in the axial direction. All of the first support surfaces  34  and all of the second support surfaces  35  lie in the same respective planes. Between a first support surface  34  and an adjacent thereto, second support surface  35 , there is provided an ascending ramp surface  33  extending from the first support surface  34 . An actuation member  36 , which is formed as a lever is connected with the bearing section  37  of the support  31  for joint rotation therewith. The actuation member  36  is accessible to the tool operator and can be operated manually.  
         [0029]     As particularly shown in  FIG. 2 , on end wall  18  of the piston guide  11 , there are provided first counter-support surfaces  14  and second counter-support surfaces  15  of the device  40 . The second counter-support surfaces  15  project beyond the first counter-support surface  14  in the axial direction. All of the first counter-support surfaces  14  and all of the second counter-support surfaces  15  lie, respectively, in the same planes. An ascending counter-ramp surface  13  is provided from the first counter-support surface  14  to the second counter-support surface  15 .  
         [0030]     As shown in  FIG. 1 , in the first position  41  of the device  40 , the first support surfaces  34  of the support  31  abut the second counter-support surfaces  15  on the end wall  18  and the second support surfaces  35  of the support  31  abut the first counter-support surface  14  on the end wall  18 . Upon actuation of the device  40  by pivoting the actuation member  36  about the longitudinal axis  19 , the support surface  31  pivots, together with the piston stopping element  30 , in the pivotal direction of the actuation member  36 . The ramp surfaces  33  slide along counter-ramp surfaces  13  on the end wall  18 , and the support  31  is lifted by some distance from the end wall  18  in a direction of the combustion chamber  16 .  
         [0031]     In the position  42  shown in  FIG. 5 , the actuation member  36  has been completely pivoted up to a stop not designated with a reference numeral. In this position of the actuation member  36 , the second support surfaces  35  of the support  31  abut the second counter-support surfaces  15  on the end wall  18 . The piston stopping element  30  and the support  31  became displaced by a certain distance in a direction toward the combustion chamber  18 , so that the maximum displacement path of the setting piston  20  has been shortened. Thereby, the maximum drive-in depth has also been reduced, as the setting piston  20 , contrary to the first position  41  (see  FIG. 1 ), will be displaced by a shorter distance until it strikes the piston stopping element  30  upon actuation of the setting tool  10  with an actuation switch (not shown).  
         [0032]     Though the present invention was shown and described with references to the preferred embodiment, such is merely illustrative of the present invention and is 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 embodiment 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.