Abstract:
A positioning device for a hand-held setting tool ( 10 ) includes an actuation element ( 24 ), a switching link ( 30 ) for connecting an actuation element ( 24 ) to the actuation switch ( 13 ) of the setting tool ( 10 ) for actuating the same, and a safety device ( 50 ) for preventing actuation of the actuation switch ( 13 ) at an orientation other than a predetermined orientation of the setting tool ( 10 ) and including at least three blocking members ( 55   a,    55   b,    55   c ) displaceable in at least three separate channels ( 56 ), respectively, and receivable in a recess ( 51 ) formed in a switching member ( 34 ), that forms part of the switching link ( 30 ) a longitudinal axis with the at least three channels ( 56 ) intersecting, in some regions, an axial projection of the switching member ( 34 ) in the form of a secant and opened toward the switching member ( 34 ) in respective overlapping regions ( 59 ).

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     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 an orientation of the setting tool other than a predetermined orientation. 
     2. Description of the Prior Art 
     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. 
     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 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 that is 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. 
     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 member 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. 
     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. 
     U.S. Pat. No. 7,014,085 discloses an explosion-actuated setting tool having a housing, an elongate 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 direction of the force of gravity. The ball of the ball-controlled device is arranged in an annular receiving space between the holder and the housing. 
     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. 
     Another drawback 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 the direction of the gravitational force, can vary depending on the changes in orientation of the setting tool prior to actuation. Moreover, when the setting tool is pressed, with a jerk, horizontally against a wall or downwardly against a floor, the blocking ball rolls out of its blocking position, and the setting tools becomes inadvertently released. 
     SUMMARY OF THE INVENTION 
     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. 
     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 least three separate channels and at least three blocking members displaceable in the at least three separate channels, respectively, with the switching member having a recess for receiving the blocking members and which opens toward the structural component, with the at least three channels being inclined with respect to a plane extending perpendicular to the longitudinal axis and with the at least three channel intersecting in some regions, an axial projection of the switching member in form of a secant and opening toward the switching member in the respective overlapping regions. The intersection of the axial projection of the switching member by the channels in form of a secant means that the channels do not extend toward the axis of the switching member but rather intersect its axial projection along periphery. 
     The novel features of the present invention insure, on one hand, that a blocking position of the safety device is reached not only at a certain orientation of the positioning device but also rotationally symmetrically with respect to the longitudinal axis in other tilting positions that deviate from the predetermined orientation. This is because at least one blocking member always lies in the overlapping region of a respective channel and extends thus, into the recess of the switching member. Thus, e.g., the blocking position is always then actuated when the positioning device is moved in a tilting position relative to a vertical (i.e., with respect to the orientation in a direction opposite to the vector of the gravitational force) that exceeds the maximum allowable tilting angle. 
     On the other hand, the maximum stroke of the switching member is not determined by the size of the blocking members. Therefore, the function, which is controlled by the press-on path such as, e.g., actuation of the setting tool or displacement of a cartridge in case of a powder charge-operated setting tool, can be determined based on an optimal force-path ratio. Thereby, a need in high pressure forces can be eliminated. It can also be desirable to be able to actuate the setting tool when the positioning device is oriented in the direction of the vector of the gravitational force and/or in a tilting, with respect to this orientation, position. 
     Advantageously, the at least three channels are distributed about the longitudinal axis rotationally symmetrically. Thereby, the blocking function provides for actuation of the safety device about its longitudinal axis at the same release angle in each rotational position. 
     Advantageously, the blocking members are formed as pin-shaped members. Thereby, a premature release of the blocking position can be prevented when the device is dynamically displaced against a wall or a floor, and the blocking members have a tendency, because of the occurring acceleration forces, to move out of their blocking position. This is because the pin-shaped blocking members contrary to the ball-shaped blocking members block the release over their entire axial length, thus, preventing the premature release of the blocking position. 
     It is further advantageous, when the structural component is formed as a coupling element having a cylindrical portion, and the switching member is formed as a rod-shaped member displaceable in the cylindrical portion of the coupling element. The coupling element forms a support along which a movable part of the switching link is guided. Thereby, the safety device insures that in case of blocking, the forces acting on the blocking member are smaller at an orientation that enables a setting process relatively far below the mass link. 
     Alternatively, the structural component can be formed, e.g., by a handle or by connection means. 
     It is advantageous, when the at least three channels are inclined to the plane which extends perpendicular to the longitudinal axis, each at an angle between 20° and 50°. This permits, on one hand, a reliable free switching at an orientation transverse to a direction opposite the direction of the vector of the gravitational force or at an orientation slightly inclined to this transverse orientation and, on the other hand, reliably blocks the actuation at an orientation perpendicular to the vector of the gravitational force (horizontal) orientation, or when a dynamic pressure acts in the direction of the gravitational force. 
     Advantageously, the overlapping region of a channel with respect to the axial projection of the switching member has a depth toward the longitudinal axis, smaller than a diameter of the channel. This insures a reliable guidance of the blocking members in the channels though the channels intersect in form of secant the axial projection of the switching member or the guide bore for the switching member. 
     It is further advantageous when the recess in the switching member is formed as an annular groove closed in both axial directions of the switching member. This insures a good access of the recess for the blocking members and their easy displacement from the channels into the recess for effecting blocking when the device is displaced in a position in which an actuation is not desired. 
     It is further advantageous when the recess in the switching member has walls that limit the recess in an axial direction and that are inclined to the longitudinal axis so that an axial width of the recess diminishes from a radially outward end to a radially inward end. Thereby, the pin-shaped blocking members have, in the blocking position, not a point but linear contact with the inclined walls of the recess. Thereby, the surface pressure in the contact region can be reduced. 
     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 
       The drawings show: 
         FIG. 1  a partially exploded view of the positioning device according to the invention with actuating switching means and with a hand-held setting tool, which is arranged at connection means, in a non-pressed position; 
         FIG. 2  a cross-sectional longitudinal, parallel to the longitudinal axis, view at an increased, in comparison with  FIG. 1 , scale, of a detail of the positioning device according to the invention in a non-actuated position and with indication of an actuated vertical orientation of the positioning device in a direction opposite the direction of the gravitational force; 
         FIG. 3  a cross-sectional longitudinal view of the detail of the positioning device shown in  FIG. 2  in the non-actuated position; 
         FIG. 4  a cross-sectional longitudinal, parallel to the longitudinal axis, view of the detail of the positioning device shown in  FIG. 2  in the non-actuated position at a horizontal orientation; 
         FIG. 5  a cross-sectional longitudinal, parallel to the longitudinal axis, view of a detail of the positioning device shown in  FIG. 2  with a vertical orientation of the positioning device in a direction of action of the gravitational force; and 
         FIG. 6  a perspective view of a detail of the positioning device shown in  FIG. 5 , in a non-actuated position. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIGS. 1 to 6  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 as 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 releasable so that the positioning device  20  can be assembled and disassembled. A longitudinal extension of the rod-shaped holder  21  defines a longitudinal axis of the positioning device  20 . Positioning devices  20  are used for carrying out overhead work on ceilings, etc. with the setting tool  10 . 
     The setting tool  10  shown in  FIG. 1  has a setting mechanism arranged in a housing  11 , which can be formed of one or more parts, for driving fastening elements into a constructional component. An actuation switch  13  is arranged on a handle  12  of the setting tool  10  for actuating a setting process. A muzzle part, designated in its entirety by a reference numeral  14 , is arranged on 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 condition of the setting tool  10  changes to a setting-ready state in which a setting process can be actuated by the actuation switch  13 . The positioning device  20  has a switching link  30  that connects an actuation element  24  of the rod-shape holder  21  with the actuation switch  13  of the setting  10 . Accordingly, the actuation element  24  acts as a remote actuation switch. 
     As can be seen in  FIG. 1 , the hand-held setting tool  10  is arranged at connection means  22  of the positioning device  20  and is releasably 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 . Alternatively, the setting tool  10  can be connected with a positioning device by a threaded connection, with an inner thread being provided on the setting tool and an outer thread being provided on the positioning device or vice versa. 
     The actuation element  24  is provided on the first part  21   a  of the rod-like holder  21  and is formed as an elongated actuating sleeve, and is guided over a supporting element  23  of a supporting structure. The 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 . 
     The actuation element  24  is displaceable parallel to the longitudinal axis A relative to the supporting element  23 . A base part  26 , which projects beyond an axial end  27  of the actuation element  24  remote from the connection means  22  is arranged at a free end  25  of the supporting element  23  or the holder  21  remote from the connection means  22 . The supporting element  23  is fixedly connected to a coupling element  28  which has 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  adjacent to the base part  26 . The spring element  42  is supported with its other end against the actuation 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 actuation element  24 . 
     The actuation 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  extends through slit-shaped opening (not shown) 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. 
     The connection means  22  is provided on 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 releasable, as it has been already mentioned above, so that the positioning device  20  can be assembled and disassembled. 
     Further, the second part  21   b  of the rod-shaped holder  21  has a third switching member  35  of the switching link  30  and 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-shaped 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 provided at a free end of the switching link  30  at the connection means  22 . Spring means  49  biases the switching link  30  at the connection means  22  and the driver  37  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 . 
     In addition to the first part  21   a  and the second part  21   b , the holder  21  can have one or more elongate parts which can be arranged between the first and second parts  21   a ,  21   b  and be provided, at their respective ends, with respective coupling and counter-coupling elements and with respective further switching members of the switching link displaceable thereat. 
     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 actuation element  24  at an orientation other than the permitted orientation. This safety device  50  is arranged between a structural component of the supporting structure, which is formed, in the shown embodiment, as a portion  46  of the coupling element  28  remote from the receptacle  36 , and a switching member of the switching link  30  which is displaceable axially along the longitudinal axis A and is formed by the second switching member  34  in the disclosed embodiment. The safety device  50  includes an annular recess  51  on the radial outer side of the second switching member  34 . The annular recess  51  opens toward the portion  46  or radially outwardly. 
     The safety device  50  further has a plurality of channels  56 , exactly three in the shown embodiment, which are provided in the portion  46  of the coupling element  28 , are distributed rotationally symmetrically about the axis A, and are inclined at angle α from 20° to 50° to a plane E extending perpendicular to the axis A (see in particular  FIGS. 2 ,  4 , and  6 ). The channels  56  have, perpendicular to their longitudinal extent, a circular cross-section. A radially outer end of the channels  56  is open at an outer surface of the coupling element  28  in the region of the portion  46 , and the radial inner end  57  of the channels  56  is closed. The channels  56  intersect in the form of a secant, in some regions, an axial projection of the second switching member  34  and are open toward the second switching member  34  in these overlapping regions  59 . A length L 2  of the channels  56  from its radially outer end  58  toward the overlapping region  59  is greater than a length L 1  of the channel  56  from its inner end  57  toward the overlapping region  59  (see  FIG. 2 ). The overlapping regions  59  of the channels  56  and the axial projection of the second switching member  34  have, toward the axis A, a depth T that is smaller than a diameter D of the channels  56  (see in particular  FIG. 3 ). A blocking member  55   a ,  55   b ,  55   c , which is formed as an elongate, cylindrical pin, is displaceably arranged in each channel  56 . The length L 1  of the channels  56  from the inner end  57  toward the overlapping region  59  is smaller than a length L 3  of the pin-shaped blocking member  55   a ,  55   b ,  55   c  (see  FIG. 2 ). Further, a length L 4  of the overlapping channel  59  in the longitudinal direction of the channel  56  is smaller than the length L 3  of the pin-shaped blocking member  55   a ,  55   b ,  55   c.    
     In the initial position of the positioning device  20  shown in  FIGS. 1-3 , the positioning device  20  is oriented with the muzzle part  14  of the setting tool  10  in a direction opposite the direction of the vector G of the force of gravity (e.g., in a direction of a ceiling). The actuation element  24  is inactive and is displaced into the cup-shaped base part  26  to the maximum distance by the spring element  42 . Therefore, the second switching member  34  is moved into the guide  44  in the coupling element  28  likewise by 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 an actuation stroke are inactive. 
       FIGS. 2 and 3  show an enlarged view of an area of the positioning device  20  with the safety device  50  being oriented with respect to the vector G of the gravitational force, as shown in  FIG. 1 . As shown, the pin-shaped blocking member  55   a  is located in the channel  56 , extending radially outwardly in a region adjacent to the radially outer end  58  and, thus, without blocking the overlapping region  59  between the portion  46  and the second switching member  34 . The other blocking members  55   b ,  55   c  (in  FIG. 2 , the blocking member  55   c  is located outside of the cross-sectional plane and is, therefore, not visible) are also located radially outwardly in the respective channels  56  in regions adjacent to respective outer ends  58 , likewise not blocking the respective overlapping regions  59 . The safety device  50  is located at this orientation of the positioning device in its actuation-permitting position. The setting tool  10 , which is attached to the positioning device, can be pressed, at this orientation, with its muzzle part  14  against a ceiling or another constructional component and can be actuated by displacement of the actuation element  24  in a direction of the coupling element  28  because the blocking members  55   a ,  55   b ,  55   c  permit a relative movement of the second switching member  34  with respect to the component of the support structure or relative to the portion  46  of the coupling element  28  due to their position outside of the first recess  51 . As shown in  FIG. 2 , the second switching member  34  is displaced by the actuation element  24  and by the first switching member  33  in direction of a first arrow  15  relative to the coupling element  28  and its portion  46  (the second switching member  34  is shown with dash lines). The second switching member  34  displaces the following portion of the switching link  30  up to the driver  37  for the actuation switch  13  (not shown in  FIGS. 2 and 3 ). Thus, at this orientation of the positioning device  20  relative to the vector G of the gravitational force, the setting tool  10  can be actuated. 
     Even when the positioning device  20  is inclined relative to the orientation shown in  FIGS. 1-3 , maximum at about 25°-50°, an actuation is still possible. This is because the pin-shaped blocking numbers  55   a ,  55   b ,  55   c  remain in the regions of the channels  56  adjacent to the radially outer ends  58 . If a pin-shaped blocking member  55   a ,  55   b ,  55   c  would only partially, i.e., with an end, extend in the overlapping channel  59 , the safety device  50  still would remain in its release position, so that the blocking member can be pressed out into a release position upon application of pressure to a groove wall  52  of the recess  51 , which extends at an angle to the axis A. 
     In  FIG. 4 , the positioning device  20  together with the safety device  50 , extends with its axis A, e.g., at right angle to the vector G of the gravitational force. As shown, one of the pin-shaped blocking members, namely, the blocking member  55   a , is located in a region of the channel  56  adjacent to the inner end  57  of the channel  56 . Therefore, due to the relationship of the length L 3  of the blocking member to the length L 1  from the inner end  57  to the overlapping region  59 , the blocking member  55   a  at least partially blocks the overlapping region  59 . Thus, the safety device  50  is in its blocking position. If the setting tool  10 , which is attached to the positioning device  20 , is pressed with its muzzle part  14  against a constructional component at this orientation, a setting process cannot be initiated by movement of the actuation element  24  of the coupling element  28 . This is because the blocking member  55   a , due to its position in the recess  51 , in the blocking position, provides only for a very short path of displacement of the second switching member  34  relative to a component of the support structure or relative to portion  46  of the coupling element  28 . This very short path is much shorter than that necessary for the switching stroke of the second switching member  34 . 
     In  FIGS. 5-6  the positioning device  20 , together with the safety device  50 , is oriented with its axis A in the direction of the vector G of the gravitational force. As shown, all of the blocking members  55   a ,  55   b ,  55   c  are located in the regions of the respective channels  56  adjacent to the respective inner ends  57  of the respective channels  56 . Therefore, due to the relationship of the length L 3  of the respective blocking members  55   a ,  55   b ,  55   c  to the length L 1  from the inner end  57  for the overlapping region  59 , the blocking members  55   a ,  55   b ,  55   c  at least partially block the respective overlapping regions  59 . Thus, the safety device  50  is in its blocking position also at this orientation. If the setting tool  10 , which is attached to the positioning device  20 , is pressed with its muzzle part  14  against a constructional component at this orientation, a setting process cannot be initiated by movement of the actuation element  24  of the coupling element  28 . This is because the blocking members  55   a ,  55   b ,  55   c  due to their position in the recess  51 , in the blocking position, provides only for a very short path of displacement of the second switching member  34  relative to a component of the support structure or relative the portion  46  of the coupling element  28 . This very short path is much shorter than that necessary for the switching stroke of the second switching member  34 . 
       FIG. 6  shows also a constructional variation of channels  56 . In  FIG. 6 , the channels  56  conically expand at their radially inner ends  57 , so that the central axes of the pin-shaped blocking members  55   a ,  55   b ,  55   c  can incline to center axes of respective channels  56 . Thereby, upon a dynamic pressure of the positioning device  20  with the setting tool  10  in the direction of the vector G of the gravitational force or transverse thereto, the blocking time, during which at least one pin-shaped blocking member  55   a ,  55   b ,  55   c  at least partially blocks the overlapping region  59 , becomes longer because the blocking member  55   a ,  55   b ,  55   c  firstly, should align with respect to the central axis of the channel  56  before it can be withdrawn from the channel  56 . 
     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.