Abstract:
A positioning device for a hand-held setting tool ( 10 ) includes an actuating switching device having an actuation element ( 24 ), a switching link ( 30 ) for connecting an actuation element ( 24 ) to the actuation switch ( 13 ) of the setting tool ( 10 ) and having a switching member axially displaceable relative to a stationary, with respect to the holder, structural component, and a safety device ( 50 ) for preventing actuation of the actuation switch ( 13 ) at a predetermined orientation of the setting tool ( 10 ) and including a displaceable blocking element ( 55 ), first and second annular recesses ( 51, 52 ) for receiving the blocking element and extending radially circumferentially about the structural component and about the switching member, respectively, with the first ( 51 ) and the second ( 52 ) annular recesses being open toward the switching member and the structural component, respectively, and with the blocking element ( 55 ) being completely positionable in one of the first and second annular recesses ( 51 ) in an operational position of the actuation switching means.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a positioning device for a hand-held setting tool having an actuation switch for actuating the setting tool, with the positioning device including a rod-shaped holder defining a longitudinal axis, connection means for the setting tool arranged at an end of the holder, actuating switching means for actuating the actuation switch of the setting tool and including an actuation element, a switching link that connects the actuation element with the actuation switch of the setting tool, and a safety device for preventing actuation of the actuation switch of the setting tool at a predetermined orientation of the setting tool. 
         [0003]    2. Description of the Prior Art 
         [0004]    Positioning devices of the type described above are used, e.g., at overhead works with hand-held setting tools in case of high ceilings when working is possible only using working platforms or ladders. Setting tools, which can be used with such devices, can be driven with solid, gaseous, or liquid fuels or with compressed air or electricity. 
         [0005]    U.S. Pat. No. 4,479,599 discloses a positioning and actuation device for a combustion-operated setting tool and including connection means for the setting tool, which is arranged at an end of an elongated holder and is formed as a rod or a bar. The rod or bar is axially displaceable relative to the connection means for actuating the actuation switch of the setting tool secured on the connection means via coupling means. For actuating the setting tool, the tool should be placed with its muzzle part against a ceiling and then be displaced in the direction of the ceiling with the holder or rod by the user. 
         [0006]    Further, the positioning and actuation device has a safety device which prevents the setting tool from being actuated when the muzzle part is oriented exactly in direction of the force of gravity. For this purpose, the safety device has a blocking element formed as a ball which is guided in a recess formed as a channel and extending in the connection means diagonally to the longitudinal axis of the rod. At an orientation of the tool in the direction of the gravitational force, the ball rolls into the movement path of the rod and prevents a further movement of the rod relative to the connection means and, therefore, prevents actuation of the setting tool secured on the connection means. To this end, the rod has, at its end adjacent to the connection means, a radially circumferential recess into which the ball can fall. 
         [0007]    The drawback here consists in that the actuation of the setting tool can only be safely prevented when the positioning and actuation device with the setting tool is oriented exactly with the muzzle part facing in direction of the force of gravity. 
         [0008]    U.S. Pat. No. 7,014,085 discloses an explosion-actuated setting tool having a housing, an elongated holder projecting therefrom, and a ball-controlled safety locking device which permits the setting tool to be actuated only in a vertical or almost vertical orientation opposite to the force of gravity. The ball of the ball-controlled device is arranged in an annular receiving space between the holder and the housing. 
         [0009]    However, the drawback of the setting tool of U.S. Pat. No. 7,014,085 consists in that the diameter of the ball defines the maximum movement path of the holder relative to the housing which is available in the release position of the ball and within which all of the necessary functions such as, e.g., initiating of ignition, must be carried out. Therefore, a very high pressing force is needed for this short movement path. 
         [0010]    Another disadvantage consists in that widely differing angles result when the setting tool is lifted upward until released, and when the setting tool is lowered until blocked again; that is, the limiting angle at which a setting process is still possible when the setting tool deviates from a vertical orientation opposite to gravitational force can vary depending on the changes in orientation of the setting tool prior to actuation. 
       SUMMARY OF THE INVENTION 
       [0011]    An object of the present invention is a positioning and actuation device of the type mentioned above which overcomes the drawbacks described above and which makes possible a sufficiently long movement path of the holder relative to the setting tool when pressing against a workpiece while at the same time requiring a small expenditure of force. 
         [0012]    This and other objects of the present invention, which will become apparent hereinafter, are achieved according to the invention, by providing a positioning device the safety device of which includes a first annular recess for receiving the blocking element and extending radially circumferentially about a stationary, with respect to the connection means, structural component, and a second annular recess extending radially circumferentially about the switching member and located, at least in an initial position of the positioning device radially opposite the first annular recess. The first annular recess and the second annular recess are open toward the switching member and the structural component, respectively. The blocking element is completely positionable in one of the first and second annular recesses in an operational position of the actuation switching means. 
         [0013]    The safety device acts in a rotationally symmetrical manner in identical tilting positions. Therefore, the blocking position of the safety device is achieved not only at certain orientation of the positioning device, but also remains rotationally symmetrical to the longitudinal axis in other tilting positions of the setting tool which deviate from the permissible orientation. For example, the blocking position can always be initiated when the positioning device is moved into a tilting position relative to the vertical (i.e., the orientation opposite to the vector of the force of gravity) which exceeds a maximum permissible tilting angle. On the other hand, the required stroke of the switching link can be longer than the maximum extension or dimension of the blocking element or blocking ball. Therefore, the functions which are controlled by the press-on path such as, e.g., the actuation of the setting tool or the transport of cartridges in powder-operated setting tools can be designed based on the optimal force/path behavior. Therefore, high press-on forces can be avoided. It may also be desirable that the setting tool can be actuated when the positioning device is arranged in an orientation in direction of the vector of the force of gravity and/or in a tilted position relative to this orientation. 
         [0014]    The structural component in which the first annular recess is arranged is advantageously formed by a portion of a coupling element. This coupling element belongs to the supporting structure at which the switching link with its moving parts is guided so that, in an orientation in which a setting process is possible, the safety device is relatively far down in the line of mass so that the forces acting on the ball and blocking element are smaller during blocking. 
         [0015]    Alternatively, the structural component element could also be formed, e.g., by a grip piece or by the connection means. 
         [0016]    It is advantageous when the switching member with the second recess is a first switching member of the switching link which is sleeve-shaped and is guided over the radial outer surface of the portion of the coupling element. This enables a compact construction and a simple integration of the safety device in the positioning device. 
         [0017]    It is further advantageous when the recesses are formed as annular grooves which are closed in both axial directions so that a closed receiving space is provided for the blocking element or blocking ball between the first switching member and the portion of the coupling element. 
         [0018]    One of the recesses advantageously has a pocket-shaped depression whose maximum length is greater than the greatest extension (or diameter) of the blocking element, and the other recess has a maximum radial depth which is smaller than the radial extension (or diameter) of the blocking element. The depression forms a space into which the blocking element can move entirely in an operational position of the actuation switching means in a gravity-controlled manner, while in the blocking position it lies partly in the first recess and partly in the second recess and, accordingly, does not permit a movement of the two parts relative to one another or, if so, only for a short stroke path. 
         [0019]    The pocket-shaped depression is advantageously defined axially at its end remote from the connection means by an inclined surface which is inclined from the outer side to the inner side toward the free end of the holder relative to the longitudinal axis of the holder. The angle of inclination of the inclined surface relative to the longitudinal axis defines, in a simple manner, the maximum permissible tilting angle of the positioning device relative to the vertical at which the blocking element still remains in the depression and, therefore, in the actuation position of the actuation switching means. 
         [0020]    A clearance angle or releasing angle of 15° to 30° for the actuation switching means position is advantageously achieved with an angle of inclination of the inclined surface to the longitudinal axis in the range of 60° to 75°. 
         [0021]    It is also advantageous when the recesses form conical boundary surfaces at their axial ends remote from the free end, which conical boundary surfaces narrow the recesses in the direction away from the free end of the holder. This results in a surface support in the blocking position so that the blocking element or ball blocks in a reliable manner in the perpendicular orientation in direction of the vector of gravitational force. Further, a jamming of the ball or blocking element is prevented at an inclination in direction of the vector of gravitational force so that when moving into a different position this ball or blocking element can roll out again from the funnel that is formed. 
         [0022]    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 
         [0023]    The drawings show: 
           [0024]      FIG. 1  a partially exploded view of the positioning device according to the invention with an actuating switching means and with a hand-held setting tool, which is arranged at connection means, in a non-pressed position; 
           [0025]      FIG. 2  a cross-sectional view at an increased, in comparison with  FIG. 1 , scale, of a detail of the positioning device according to the invention according to section II in  FIG. 1  in the inactive position in a vertical orientation; 
           [0026]      FIG. 3  a cross-sectional view of the detail of the positioning device shown in  FIG. 2  in the actuated position; 
           [0027]      FIG. 4  a cross-sectional view of the detail of the positioning device shown in  FIG. 2  in the inactive position in a horizontal orientation; 
           [0028]      FIG. 5  a cross-sectional view of a detail of the positioning device shown in  FIG. 2  in the horizontal orientation in a blocking position of the blocking element; and 
           [0029]      FIG. 6  a cross-sectional view of a detail of the positioning device shown in  FIG. 2  at an increased, in comparison with  FIG. 2 , scale. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0030]      FIGS. 1 to 5  show a positioning device  20  according to the invention with actuating switching means for a hand-held setting tool  10  and which can be formed a modular unit, for example. In the complete positioning device  20 , the parts  21   a  and  21   b  of a rod-shaped holder  21 , which are shown in  FIG. 1  are coupled with one another by a coupling element  28  and a counter-coupling element  29 . The connection between the coupling element  28  and the counter-coupling element  29  is detachable so that the positioning device  20  can be assembled and disassembled. One or more lengthening elements, not shown in the drawings, may be added between the two parts  21   a  and  21   b  of the rod-shaped holder  21 . The longitudinal extension of the rod-shaped holder  21  defines a longitudinal axis A of the positioning device  20 . 
         [0031]    The setting tool  10  shown in  FIG. 1  has a setting mechanism arranged in a housing  11  and having one or more parts for driving fastening elements into a constructional component. An actuation switch  13  is arranged at a holder  12  of the setting tool  10  for actuating a setting process. A muzzle part, designated in its entirety by  14 , is arranged at the setting tool  10  in front of the housing  11  and can be displaced relative to the housing  11 . When the muzzle part  14  of the setting tool  10  is pressed against a construction component (not shown in the drawings), the setting tool  10  changes to a ready state in which a setting process can be actuated by the actuation switch  13 . The positioning device  20  has a switching link  30  by means of which the actuating switching means is connected with the actuation switch  13  of the setting  10 . The actuating switching means includes an actuation element  24  of the rod-shape holder  21 . Accordingly, the actuation element  24  acts as a remote actuation switch. 
         [0032]    As can be seen from  FIG. 1 , the hand-held setting tool  10  is arranged at connection means  22  of the positioning device  20  and is reversibly secured thereto by first holding element  38  and second holding element  39 . The setting tool  10  can be detached from the connection means  22  by loosening the screw means  40  of the second holding element  39 . 
         [0033]    The first part  21   a  of the rod-like holder  21  has an actuating element  24  which is formed as an elongated actuating sleeve and which is guided at a supporting element  23  of a supporting structure, which supporting element  23  is formed as a hollow bar. As an alternative to an actuating sleeve, an actuating lever could also be used and, e.g., arranged at a grip part at an end of the holder  21  remote from the coupling element  28 . 
         [0034]    The actuating element  24  is displaceable parallel to the longitudinal axis A relative to the supporting element  23 . A base part  26  which projects over an axial end  27  of the actuating element  24  remote from the connection means  22  is arranged at a free end  25  of the supporting element  23  or holder  21  remote from the connection means  22 . The supporting element  23  is fixedly connected to a coupling element  28  having a receptacle  36  for a counter coupling element  29  at its end remote from the supporting element  23 . A support point  41  for a spring element  42  is formed at an end of the coupling element  28  facing the base part  25 . The spring element  42  is supported with its other end against the actuating element  24  by an intermediate element  43  formed as an inner sleeve and elastically loads the latter in direction of its initial position which is shown in  FIG. 1 . The intermediate element  43  is fixedly connected to the actuating element  24 . 
         [0035]    The actuating element  24  is connected to a sleeve-shaped, first switching member  33  of the switching link  30  which at least partially surrounds a portion  46  of the coupling element  28  that is secured to the supporting element  23 . The first switching member  33  cooperates with a second switching member  34  of the switching link  30  which is formed as a pin and which is displaceably guided in a guide  44  in the coupling element  28  that is formed as a blind hole. The first switching member  33  is in turn connected to the second switching member  34  by a connection element  47  which extend perpendicular to the longitudinal axis A and is formed as a stud. The connection element  47  penetrates slit-shaped openings  48  in the portion  46  of the coupling element  28  which make it possible for the connection means  47  to be displaced relative to the coupling element  28  and parallel to the longitudinal axis A. 
         [0036]    The connection means  22  is arranged at the second part  21   b  of the rod-shaped holder  21 . At its end remote from the connection means  22 , this second part  21   b  of the rod-shaped holder  21  has an annular counter coupling element  29  which, as has already been described, can be inserted into the receptacle  36  of the coupling element  28 . The connection between the coupling element  28  and the counter coupling element  29  is detachable so that the positioning device  20  can be assembled and disassembled. 
         [0037]    Further, in the second part  21   b , the rod-shaped holder  21  has a third switching member  35  of the switching link  30  which cooperates with the second switching member  34  when the coupling element  28  and the counter coupling element  29  are connected to one another. The third switching member  35  is rod-shaped and is guided in an interior space of the second part  21   b  of the rod-shaped holder  21 . At the transition from the rod-like holder  21  to the connection means  22 , the third switching member  35  can be coupled with additional switching members of the switching link  30  at least in the movement direction toward the connection means  22 . Further, a driver  37  which cooperates with the actuation switch  13  of the setting tool  10  arranged at the connection means  22  is arranged at a free end of the switching link  30  at the connection means  22 . The switching link  30  at the connection means  22  is acted upon by the driver  37  via spring means  49  in direction of its inactive position, shown in  FIG. 1 , in which the driver  37  does not press against the actuation switch  13  of the setting tool  10 . 
         [0038]    Further, the positioning device  20  has a safety device, designated in its entirety by  50  (see especially  FIGS. 2 to 6 ), which prevents the setting tool  10  arranged at the positioning device  20  from being actuated by the actuating element  24  in an orientation other than the permitted orientation. This safety device  50  is arranged between a structural component of the supporting structure—the portion  46  of the coupling element  28  remote from the receptacle  36  in the present embodiment example—and a switching member of the switching link  30  which is displaceable axially along the longitudinal axis A, the first switching member  33  in the disclosed embodiment. The safety device  50  has a first annular recess  51  on the radial outer side in portion  46 . The first annular recess  51  opens toward the first switching member  33  and has a radially circumferential pocket-shaped depression  53  at its axial end facing the support point  41 . The pocket-shaped depression  53  is defined at its axial end facing the free end  25  by an inclined surface  56  which is inclined at an angle of inclination α of about 75° from the outer side to the inner side toward the free end  25  of the holder ( 21 ) relative to the longitudinal axis A. Further, the first annular recess  51  has a first conical boundary surface  54  which slopes upward toward the radial outer side from the pocket-shaped depression  53  to its other axial end. The cone angle of the first conical boundary surface  54  relative to the longitudinal axis A is in the range of about 25° to 35°, although other cone angles are also possible. Further, the safety device  50  has a second annular recess  52  on the radial inner side in the first switching member  33 . The second annular recess  52  opens toward portion  46  and has a radial depth T which is less than a maximum length L of the pocket-shaped depression  53 . The second annular recess  52  has a second conical boundary surface  57  at its end facing the connection means  22  whose angle of inclination relative to the longitudinal axis A corresponds, with the opposite mathematical sign, to the angle of inclination of the first conical boundary surface  54 . 
         [0039]    Further, the safety device  50  includes a blocking element  55  which is formed as a ball and whose dimension or diameter is selected in such a way that it can be received in its entirety in the pocket-shaped depression  53 , i.e., the maximum extension D of the blocking element  55  or the diameter of the ball is smaller than the maximum length L of the pocket-shaped depression  53  and also smaller than its axial height. However, the radial extension E or the diameter of the blocking element  55  is greater than the radial depth T of the second recess  52 . 
         [0040]    In the initial position of the positioning device  20  shown in  FIGS. 1 and 2 , the positioning device  20  is oriented with the muzzle part  14  of the setting tool  10  opposite the direction of the vector G of the force of gravity. The actuating element  24  is inactive and is displaced into the cup-shaped base part  26  to the maximum distance via the spring element  42 . Therefore, the second switching member  34  is moved into the guide  44  in the coupling element  28  likewise to the maximum distance. The third switching member  35  and the rest of the switching link  30  with the driver  37  following in the direction of stroke are inactive. 
         [0041]      FIG. 2  shows an enlarged view of the area of the positioning device  20  with the safety device  50  oriented to the vector G of gravitational force, shown in  FIG. 1 . As can be seen, the blocking element  55  or ball is situated completely in the first recess  51  in portion  46 , more precisely in its radially circumferential pocket-shaped depression  53 . The position of safety device  50  corresponds to an operational position  59  of the actuation switching means. In this orientation, the setting tool  10  at the positioning device  20  can be pressed with its muzzle part  14  against a ceiling or another construction element, and a setting process can be actuated by displacing the actuating element  24  relative to the coupling element  28  because the blocking element  55 , in view of its position entirely inside the first recess  51 , permits a movement of the first switching member  33  relative to the structural component part of the supporting structure or portion  46  of the coupling element  28 . As can be seen from  FIG. 3 , the first switching member  33  is displaced by the actuating element  24  in direction of the first arrow  15  relative to the coupling element  28  and its portion  46 . By means of the first switching member  33 , the second switching member  34  (second arrow  16 ) and, along with it, the following portion of the switching link  30  up to the driver  37  for the actuation switch  13  is actuated (not shown in  FIG. 3 ) by the intermediate element  47  so that the setting tool  14  is actuated at the connecting portion  22  in this orientation to the vector G of the gravitational force. Also, actuation is still possible at an inclination of the positioning device  20  to the illustrated orientation of a maximum of approximately 15° to 30° because the ball would still be held in the radially circumferential pocket-shaped depression  53  since the inclined surface  56  is at a tilting angle of less than 90° to an axis defined by the vector G of the force of gravity and the blocking element  55  and blocking ball are accordingly prevented from moving out of the pocket-shaped depression  53 . 
         [0042]    In  FIG. 4 , the area of the positioning device  20  with the safety device  50  is oriented with its longitudinal axis A, for example, at a right angle to the vector G of the force of gravity. As can be seen, the blocking element  55  or ball is now located partly in the second recess  52  in the first switching member  33  and partly in the first recess  51  in portion  46 . Therefore, the safety device  50  is now located in its blocking position  58 . If the setting tool  10  at the positioning device  20  is pressed against a construction element by the muzzle part  14  in this orientation, a setting process can no longer be initiated by displacing the actuating element  24  toward the coupling element  28  because the blocking element  55  in this blocking position  58 , in view of its position in the two recesses  51 ,  52 , only permits a movement of the first switching member  33  relative to the structural component of the supporting structure or portion  46  of the coupling element  28  for a very short distance which is shorter than the required switching stroke. 
         [0043]    As can be seen from  FIG. 5 , the first switching member  33  can be displaced by a further distance by the actuating element  24  in direction of the third arrow  17  relative to the coupling part  28  and its portion  46 . The second switching member  34  is now also displaced by the first switching member  33  by this same stroke length in direction of the fourth arrow  18  by means of the intermediate element  47 . However, the following portion of the switching link  30  up to the driver  37  for the actuation switch  13  is either not actuated at all (not shown in  FIG. 3 ) because a coupling is no longer produced, or is displaced only by an insufficiently long stroke so that the setting tool  10  at the connection part  22  is not actuated in this orientation to the vector G of the force of gravity. In all other orientations which deviate from the indicated inclination of approximately 0° to 15° (a maximum of 30° is also possible instead of 15°) to the orientation indicated in  FIGS. 1 to 3 , the safety device  50  behaves as described with reference to  FIGS. 4 to 5  and prevents actuation. 
         [0044]    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.