Patent Publication Number: US-2019175297-A1

Title: Medical device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority under 35 U.S.C. § 119 of German Application 10 2017 129 692.1, filed Dec. 13, 2017, the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The invention relates to a medical device comprising a hinge arrangement which is configured for a pivot motion of a first hinge part in relation to a second hinge part, having a first hinge part, which comprises two hinge arms, which are arranged at a distance apart, and a hinge pin, which is extended between the hinge arms along a longitudinal axis and defines a pivot axis of the hinge arrangement, and having a second hinge part, which in certain areas is accommodated between the two hinge arms and which is passed through by a hinge cavity, wherein the hinge pin is accommodated in a pivotably movable manner in the hinge cavity. 
     BACKGROUND 
     A hinge arrangement of this type is used, for instance, in a holder for a medical instrument, wherein it can be provided to fix the medical instrument with a clamping device, said clamping device comprising a hinge arrangement. 
     SUMMARY 
     An object of the invention consists in providing a hinge arrangement which, even in the event of an occasional application of high forces, ensures a low friction for a pivot motion of the two hinge parts relative to each other. 
     It is herein provided that the hinge pin and the hinge cavity has a central contact region, with a touching contact between hinge pin and hinge cavity, and clearance regions, which border the contact region on both sides and are extended up to the hinge arms, without touching contact between hinge pin and hinge cavity, in order to ensure an exclusively central force transmission between the hinge pin and the hinge cavity. 
     The exclusively central force transmission means that the hinge pin, away from the contact region in the two clearance regions, when forces are applied to the two hinge parts, can perform a deflection motion and can hereupon be elastically deformed. Undesirable friction effects between the hinge pin and the hinge cavity, which in the long term could lead to damaging of the hinge arrangement, can hence be avoided. When a force and/or a torque is applied to the two hinge parts, the hinge pin, away from the contact region in the respective clearance region, is deformed in an S-shape. Insofar as a force is applied to the two hinge parts exclusively in a direction transversely to the longitudinal axis, the hinge pin is deformed in an S-shape in mirror symmetry to a mirror plane which is oriented perpendicular to the longitudinal axis. If, on the other hand, a torque is applied to the two hinge parts, wherein the torque about a torque axis oriented transversely to the longitudinal axis, then an S-shaped deformation of the hinge pin in the respective clearance regions takes place in axial symmetry to the torque axis. 
     It is expedient if the hinge cavity is configured as a stepped bore having a centrally arranged guide bore which has a smaller cross section than clearance bores which border this same on both sides. A cost-effective creation of the guide bore is thereby enabled, since only the clearance bores must have a larger cross section, while the guide bore has a smaller cross section, the profiling of which is matched in such a way to a profiling of the hinge pin that the hinge pin can form with the guide bore a slide bearing. Preferredly, it is provided that the guide bore and the clearance bores are respectively of circular cylindrical configuration and, in particular, are arranged coaxially to one another. In addition, it can be provided that the cross sections of the two clearance bores are identical. 
     Preferably, it is provided that the hinge pin between the hinge arms is configured with a constant profiling. Preferably, the hinge pin has a circular profiling and is thus designed as a circular cylinder, whereby a cost-effective manufacturing method for the hinge pin can be realized. 
     In an alternative refinement of the invention, it is provided that the hinge pin is configured with a centrally arranged guide portion, which has a larger cross section than clearance portions which border this same on both sides. As a result, a particularly advantageous elasticity for the hinge pin can be realized, since the centrally arranged guide portion, due to its larger cross section, within the framework of the maximum forces envisioned for the hinge arrangement, can be formed dimensionally stable, while the clearance portions which border this same, due to the smaller cross section, can be elastically deformed already in case of forces markedly below the maximum forces envisioned for the hinge arrangement. Preferably, both the guide portion and the clearance portions which border this same are respectively of circular cylindrical configuration and arranged coaxially to one another. 
     In a further embodiment of the invention, it is provided that the hinge cavity is configured as a bore having a constant profiling. The hinge cavity can hence be created by a single production procedure, in particular a drilling procedure. 
     It is advantageous if the hinge pin is configured with a centrally arranged guide portion, which has a larger cross section than clearance portions which border this same on both sides, and that the hinge cavity is configured as a stepped bore having a centrally arranged guide bore, which has a smaller cross section than clearance bores which border this same on both sides. Through the matching of the cross sections of the clearance portions to the cross sections of the clearance bores, an advantageous adjustment of the desired elasticity for the hinge arrangement can be obtained. 
     Preferredly, it is provided that mutually opposing surfaces of the hinge arms form with adjacent surfaces of the second hinge part a sliding guide with play, and that the hinge pin and the hinge cavity are mutually coordinated in such a way that, when the second hinge part is tilted in relation to the first hinge part about a tilt axis oriented transversely to the longitudinal axis, an exclusively elastic deformation of the hinge pin obtains. The sliding guide between the two hinge parts serves, in particular, to absorb forces or force components which are oriented parallel to the longitudinal axis of the hinge pin and are not supported by the hinge pin and the corresponding hinge cavity. In addition, the sliding guide between the two hinge parts serves to limit a tilting between the first hinge part and the second hinge part about a tilt axis oriented transversely to the longitudinal axis. Due to the elasticity of the hinge pin, in comparison to known hinge arrangements which are realized with rigid hinge pins, larger tilt angles for the two hinge parts relative to one another can be accepted. As a result, a clamp mounting, for instance, which is equipped with a hinge arrangement according to the invention can favorably adapt to different external geometries of objects to be clamped without an undesirable stiffness of the hinge arrangement having to be accepted in return. 
     It is expedient if an extent of the central contact region in the direction of the longitudinal axis amounts to less than 30 percent, preferably less than 25 percent, of an extent of one of the clearance regions in the direction of the longitudinal axis. 
     In an advantageous refinement of the invention, it is provided that a cross-sectional area of the guide bore amounts to less than 50 percent, preferably less than 40 percent, in particular less than 30 percent, of a cross-sectional area of the clearance bore. 
     In a further embodiment of the invention, it is provided that a cross-sectional area of the clearance portion amounts to less than 50 percent, preferably less than 40 percent, in particular less than 30 percent, of a cross-sectional area of the guide portion. 
     Advantageous embodiments of the invention are represented in the drawing. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a schematic representation of a medical device which comprises a hinge arrangement as a component part of a clamping device; 
         FIG. 2  is a schematic detailed representation of the clamping device according to  FIG. 1 ; 
         FIG. 3  is a schematic top view of the clamping device according to  FIG. 2 ; 
         FIG. 4  is a detailed representation of the clamping device according to  FIGS. 2 and 3  having a first embodiment of a hinge arrangement, in which the hinge pin is configured with a centrally arranged guide portion which has a larger cross section than clearance portions which border this same on both sides; 
         FIG. 5  is a detailed representation of the clamping device according to  FIGS. 2 and 3  having a second embodiment of a hinge arrangement, in which the hinge cavity is configured as a stepped bore and the hinge pin has a constant profiling; 
         FIG. 6  is a schematized representation of a hinge pin upon an exclusive application of radial forces; and 
         FIG. 7  is a schematized representation of a hinge pins upon an exclusive application of a torque about a torque axis oriented transversely to a longitudinal axis of the hinge pin. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to the drawings, a medical device  1  represented in  FIG. 1  is configured, purely by way of example, as a mobile supporting arm for a medical instrument (not represented in detail), for instance an endoscopic camera systems. 
     The medical device  1  comprises a base frame  2 , which is equipped with rollers  3  and which has a column  4  which extends upward substantially in the vertical direction. On the column  4 , a first supporting arm portion  5  is arranged such that it is adjustable in height and is pivotable about a vertical axis, which first supporting arm portion, on an end region facing away from the column  4 , is coupled with a second supporting arm portion  6  which, for its part, is mounted such that it is pivotably movable on the first supporting arm portion  5  about a vertical axis (not represented). 
     On that end region of the second supporting arm portion  6  which is facing away from the first supporting arm portion  5  is configured, purely by way of example, with the interposition of a ball joint  7 , a gripping arrangement  8 , which comprises a fixed gripper claw  9  and a movable gripper claw  10 . The fixed gripper claw  9  and the movable gripper claw  10  here form a hinge arrangement  11 , which enables the pivotably movable relative movement of the movable gripper claw  10  in relation to the fixed gripper claw  9 . 
     As can be seen from the schematic representation of  FIG. 3 , the fixed gripper claw  9 , on an end region facing away from the ball joint  7 , is of fork-shaped configuration and comprises two mutually spaced hinge arms  15 ,  16 , between which, purely by way of example, is accommodated the movable gripper claw  10 . The fixed gripper claw  9  thus forms with its hinge arms  15 ,  16  a first hinge part  17 , while the movable gripper claw  10  forms a second hinge part  18 . The two hinge parts  17 ,  18  are connected to each other in a pivotably movable manner by means of a hinge pin, wherein in  FIGS. 4 and 5  different embodiments of hinge arrangements are represented. 
     Purely by way of example, in  FIG. 3  the mutually facing surfaces  43 ,  44  of the two hinge arms  15 ,  16  and the mutually opposite surfaces  45 ,  46  of the second hinge part  18  are arranged such that no bearing play for the slide bearing is evident, which bearing play is formed by these surfaces  43  to  46  for the two hinge parts  17 ,  18 . In practice, the respectively opposing surfaces  43  and  45  or  44  and  46  respectively have a slight distance apart so as not to jeopardize a smoothness of running for the hinge arrangement  11 . Accordingly, the second hinge part  18 , upon application of a torque which is oriented perpendicular to the plane of representation of  FIG. 3 , can induce a tilting of the second hinge part  18  in relation to the first hinge part  17 , as is represented symbolically in  FIG. 7 . 
     In the first embodiment of a hinge arrangement  30 , which is represented in  FIG. 4 , the two hinge arms  15  and  16  of the first hinge part  17 , as well as the second hinge part  18 , are passed through by a through bore  31 , which, purely by way of example, is of circular cylindrical configuration and which, with regard to the second hinge part  18 , can also be referred to as a hinge cavity. In the through bore  31  is provided a hinge pin  32 , which, for the illustration of its geometry additionally to the sectional representation of  FIG. 4 , is represented as a single part, and which is accommodated, for instance, in a frictionally engaged manner in the two hinge arms  15  and  16  and forms with the second hinge part  18  a pivot bearing. For this purpose, the hinge pin  32  comprises a centrally arranged guide portion  33 , which is matched to a, preferably circular, profile of the through bore  31  in such a way that a slidingly movable relative movement between the guide portion  33  and the second hinge part  18  provided with the through bore  31  is enabled. At each end, the hinge pin  32  is provided with holding portions  34 ,  35 , which are fixed in non-positive engagement in the hinge arms  15 ,  16  and hence ensure a rotationally secure connection between the hinge pin  32  and the first hinge part  17 . 
     On both sides of the guide portion  33 , along a longitudinal axis  38  serving as a pivot axis for the second hinge part  18 , clearance portions  36 ,  37  respectively extend up to the holding portions  34  or  35 . The clearance portions  36  and  37  here have a considerably smaller cross section, in particular a considerably smaller diameter, than the guide portion  33 . Through this geometric design of the hinge pin  32 , it is ensured that a force transmission between the second hinge part  18  and the hinge pin  32  fixed to the first hinge part  17  obtains exclusively in the region of the guide portion  33 , and that the clearance portions  36  and  37 , due to their, compared with the guide portion  33 , considerably smaller cross sections, enable an advantageous elasticity for the hinge arrangement  33 . 
     In the second embodiment (represented in  FIG. 5 ) of a hinge arrangement  50 , in which the hinge pin  52  is accommodated in non-positive engagement in guide portions  53 ,  54  of the hinge arms  15 ,  16  and has along a longitudinal axis  55  a constant profiling, the hinge cavity configured as a through bore  51  is realized as a stepped bore. The through bore  51  herein comprises a centrally arranged guide bore  56 , the cross section of which is matched to the cross section of the hinge pin  52  so as to form a pivotably movable slide bearing. Away from the guide bore  56  extend clearance bores  57 ,  58 , which border this same on both sides and secure the clearance regions without touching contact between the hinge pin  52  and the through bore  51  that serves as the hinge cavity. 
     From the purely schematic representation of  FIGS. 6 and 7 , which relate to the hinge pin  32  according to the first embodiment of the hinge arrangement  30 , yet also apply in similar fashion to the hinge arrangement  50 , it emerges that, upon application of a purely radial force  40 , which, via the second hinge part  18 , is mounted in the guide portion  33 , an S-shaped deformation of the two clearance portions  36 ,  37  is realized in mirror symmetry to a mirror plane  41 . 
     When a torque  42  is applied to the guide portion  33  about a torque axis oriented perpendicular to the plane of representation of  FIG. 7 , there is obtained, on the other hand, a tilting of the guide portion  33  in relation to the holding portions  34  and  35 , in which the clearance portions  36  and  37  are likewise respectively deformed in an S-shape, wherein the geometric relationship between the two clearance portions  36  and  37  is here a mirroring about the torque axis. 
     While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.