Abstract:
The present invention relates to a removable handle ( 1 ) for a surgical rasp ( 2 ) or similar, the handle ( 1 ) and the rasp ( 2 ) cooperating, at right angles to their joining ends, via contact faces which at least intersect the mean direction of transmission of the forces between the handle ( 1 ) and the rasp ( 2 ), said handle ( 1 ) having a detachable assembly device ( 5 ) and being characterized in that the detachable assembly device ( 5 ) has, on the one hand, a means of assembly ( 6 ) by engagement in a direction generally perpendicular to said contact faces and using at least two complementary elements, namely a hollow tenon ( 7 ) and a mortice ( 8 ), and, on the other hand, a locking means ( 9 ) for locking said complementary elements ( 7, 8 ) in their engaged position, that is to say when the removable handle ( 1 ) and the rasp ( 2 ) are joined together, with their contact faces applied against each other.

Description:
TECHNICAL FIELD 
       [0001]    This invention relates to a removable handle provided with a device for detachable assembly and intended to be mounted on a tool and more specifically but not exclusively on a rasp or the like used in particular for a surgeon for calibrating or grinding the end of the femur of a patient during implantation of a femoral prosthesis. 
       PRIOR ART 
       [0002]    For many years already, it has been routine to provide a joint replacement, in particular the femur on the pelvis, for all or some of said joint. It is then possible to replace, with a prosthesis, the head of the femur or the acetabular cup or both of these joint elements. 
         [0003]    For the placement more particularly of a femoral prosthesis, the surgeon must first choose, from a line of femoral prostheses, the prosthesis most adapted to the morphology of the patient and in particular the length of the femoral neck. For this choice, the surgeon must perform a certain number of tests before selecting one and placing it definitively. 
         [0004]    Then, for the placement of the prosthesis chosen, after having removed the femoral head, the surgeon must prepare the medullary cavity of the femur using a surgical rasp or the like, the conformation of which is very similar to the rod of said prosthesis which will be engaged in the medullary canal of the femur. In order to obtain the final preparation, the surgeon will successively use a number of rasps having a homothetic shape, of increasing sizes, in order to prepare the medullary cavity in several successive steps. For this, the surgeon successively secures the different rasps to one of the ends of a removable handle in order to press each rasp into the medullary canal of the femur while tapping on the free end of said handle, the latter being provided at this free end with a hitting head and a device for quick detachable assembly of the fitting type in a direction perpendicular to the joint plane between the handle and the rasp, enabling said fitting to be locked in translation in order to prevent any undesired separation. In addition, the latest developments in hip prostheses, such as modular necks, require femoral rasps provided with a female housing capable of enabling a removable handle to be fitted. 
         [0005]    In this regard, numerous removable handles provided with a device for detachable assembly comprising male fitting means are already known. However, the known removable handles are provided with a device for detachable assembly not making it possible to obtain blocking without play between said handles and the rasps. This residual play in particular has the effect of allowing a slight rotation and/or a slight translation of the rasp with respect to the associated handle. These slight movements may affect the assessment of the primary stability of the rasp in the femur and therefore the assessment of the primary stability of the prosthesis. This residual play may also appear over time due to wear of the parts and their assemblies. 
         [0006]    Finally, as the housing, in particular female, of the rasps enabling the fitting of the removable handle is not entirely standardized, each prosthesis manufacturer has a line of rasps with its own housing model and therefore offers to provide the surgeon having its rasp line with a removable handle with a device for quick detachable assembly compatible with the housing of its rasps. Consequently, when the handle is broken or when the rasps are worn or broken, the surgeon must either use the same prosthesis manufacturer in order to replace the handle or the associated rasp line, or purchase prostheses from another manufacturer in order to obtain a new line of rasps as well as a new removable handle because the handles are not, in principle, compatible from one prosthesis manufacturer to another. 
       DESCRIPTION OF THE INVENTION 
       [0007]    The objective of this invention is therefore to overcome the disadvantages cited above and to propose a removable handle provided with a device for detachable assembly and intended to be mounted on a tool, of the surgical rasp type or the like, said assembly device ensuring blocking without residual play enabling immobilization in translation as well as rotation of the handle with respect to the rasp, said device for detachable assembly being capable of being rendered compatible, at a low cost, with a large majority of the rasps provided with a female housing available on the market. 
         [0008]    According to the invention, a removable handle for a tool, and more specifically, but not exclusively, for a surgical rasp or the like, is therefore proposed, the handle and the rasp cooperating at right angles to their assembly ends by contact faces which at least intersect the mean direction of transmission of forces between the handle and the rasp. Said handle comprising a device for detachable assembly is notable in that the device for detachable assembly has, on the one hand, means for assembly by fitting, in a direction generally perpendicular to said contact faces, implementing at least two complementary members, namely a hollow tenon and a mortise, respectively secured to the removable handle and the rasp and, on the other hand, means for locking said complementary members in their fitted position, i.e. when the removable handle and the rasp are secured, their contact faces being applied one against the other, said locking means comprising at least:
       a mobile slide capable of sliding at least partially inside the tenon in a direction substantially parallel to the direction of fitting of said assembly means between a “locked assembly” position in which it prevents any detachment between the removable handle and the rasp and a “free assembly” position in which it enables the handle to be released,   a notch formed on the mortise,   a blocking member arranged at least partially inside the tenon and capable of cooperating simultaneously with the slide and the notch when the tenon is fitted in the mortise, and   a maneuvering lever pivoting with respect to the handle between at least two actuation positions, namely a “closed lever” position and an “open lever” position at least indirectly determining, respectively, the “locked assembly” and “free assembly” positions of the slide,       
 
         [0013]    and in that the respective shapes of the slide and the notch are such that, when the tenon of the handle is fitted in the mortise of the rasp and the maneuvering lever is in the “closed lever” position, the blocking member moves away toward the outside of the tenon while bearing on the notch so as to generate a clamping force, one against the other, of the respective contact faces of the handle and the rasp. 
         [0014]    Advantageously, the locking means comprise at least one push-member articulated at each of its ends to the slide and to the maneuvering lever around axes substantially parallel to the axis of rotation of said maneuvering lever in order to transmit the movement of the maneuvering lever to the slide. 
         [0015]    The maneuvering lever-push-member-slide assembly is configured in the form of a mechanical swivel. 
         [0016]    The push-member is advantageously extendable. In this regard, the push-member has a screw-nut assembly with a differential pitch and/or a resilient member advantageously of the spring washer, called “Belleville” washer, type. 
         [0017]    The tenon preferably has at least one hole passing through the thickness of said tenon, capable of receiving the blocking member and sized so as to enable the latter to go only partially beyond the outer face of the tenon while retaining it so as to prevent it from completely emerging from the hole and said tenon. 
         [0018]    Similarly, the slide has a generally parallelepiped head, the longitudinal cross-section of which is generally trapezoidal so as to have at least one lateral face inclined with respect to the direction of fitting of the assembly means and in the direction of the free end of the tenon, said lateral inclined face comprising a longitudinal channel arranged opposite said hole when the head is inside said tenon and capable of cooperating with the blocking member. 
         [0019]    Advantageously, the notch is arranged opposite said hole when the tenon is fitted in the mortise and inclined with respect to the direction of fitting of the assembly means and in the direction of the free end of the mortise, said notch being inclined in the opposite direction with respect to the inclination of the associated channel. 
         [0020]    According to a preferred embodiment, the locking means comprise two blocking members and two notches formed opposite one another on the mortise along an axis substantially perpendicular to the direction of fitting of the assembly means and symmetrically with respect to the longitudinal axis of the mortise, the tenon comprises two holes arranged opposite one another along an axis substantially perpendicular to the direction of fitting of the assembly means, and the head has a longitudinal cross-section with a general regular trapezoid shape so as to have two lateral faces symmetrically inclined with respect to the direction of fitting of the assembly means and in the direction of the free end of the tenon and each comprising a longitudinal channel. 
         [0021]    Each blocking member is advantageously a ball. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0022]    Other advantages and features will become more clear from the following description of an embodiment of a removable handle provided with a device for detachable assembly according to the invention with reference to the appended figures, wherein: 
           [0023]      FIG. 1  is a front view of a handle provided with a device for detachable assembly according to the invention associated with a rasp; 
           [0024]      FIG. 2  is a partial view of the handle of  FIG. 1  with the maneuvering lever in the “closed lever” position; 
           [0025]      FIG. 3  is an enlarged partial vertical cross-section view of a detail of  FIG. 2 ; 
           [0026]      FIG. 4  is a partial perspective view of the handle similar to that of  FIG. 2  with the maneuvering lever in the “open lever” position; 
           [0027]      FIG. 5  is an enlarged detail view of the end of the handle of  FIG. 4 ; 
           [0028]      FIG. 6  is a partial perspective view of the handle of  FIG. 2 ; 
           [0029]      FIG. 7  is an enlarged detail view of the end of the handle of  FIG. 6 . 
       
    
    
     IMPROVED METHOD OF PRODUCING THE TECHNICAL INVENTION 
       [0030]    A removable handle provided with a device for detachable assembly enabling the assembly of said handle on a tool, of the surgical rasp type or the like, will be described below. It goes without saying that said device for detachable assembly may be used to secure, without play, said handle on a tool of any other type without going beyond the context of this invention. 
         [0031]    In reference to  FIG. 1 , the removable handle  1  is mounted on a rasp  2  used in particular by a surgeon in order to calibrate or grind the end of the femur of a patient during implantation of a femoral prosthesis. The handle  1  and the rasp  2  cooperate at right angles to their assembly ends by respective contact faces  3 ,  4 , which at least intersect the mean direction of transmission of forces between the handle  1  and the rasp  2 . 
         [0032]    In reference to  FIGS. 2 to 7 , the removable handle  1  includes a device  5  for detachable assembly enabling the removable handle  1  to be mounted on the rasp  2 . 
         [0033]    The assembly device  5  includes, on the one hand, means  6  for assembly by fitting, in a direction generally perpendicular to the respective contact faces  3 ,  4  of the handle  1  and the rasp  2 , implementing at least two complementary members, namely a tenon  7  and a mortise  8 , and, on the other hand, means  9  for locking said complementary members  7 ,  8  in their fitted position, i.e. when the removable handle  1  and the rasp  2  are secured one with the other. 
         [0034]    The tenon  7  and the mortise  8  advantageously have complementary generally cylindrical or conical elongate shapes, respectively secured to the removable handle  1  and the rasp  2 , and extending substantially perpendicularly to their respective contact faces  3 ,  4 . 
         [0035]    The term cylindrical shape here refers to a shape of which the surface is defined by a straight line, called a generatrix, passing through a variable point describing a closed planar curve, called a directrix curve and maintaining a fixed direction classically perpendicular to the plane of the directrix curve. 
         [0036]    In addition, said tenon  7  is hollow and has two holes  10  arranged opposite one another along an axis substantially perpendicular to the fitting direction of the assembly means  6  and entirely passing through the thickness of the tenon  7  so as to enable the passage from the interior to the exterior of said tenon  7 . 
         [0037]    Said locking means  9  comprise a mobile slide  11  having a generally parallelepiped head  12  capable of sliding inside the tenon  7  in a direction substantially perpendicular to the contact face  3  of the handle  1  and two blocking members  13 , advantageously of the ball type, arranged inside the tenon  7 . Said slide  1  is mobile between a “locked assembly” position in which the head  12  prevents any disassembly between the removable handle  1  and the rasp  2  and a “free assembly” position in which the head  12  enables the handle  1  to be released. 
         [0038]    Said head  12  has a longitudinal cross-section with a general regular trapezoid shape so as to have two parallel lateral faces  14  and two lateral inclined faces  15  with respect to the direction of fitting of the assembly means  6  and in the direction of the free end of the tenon  7 . In other words, the more one moves toward said free end, the narrower the head  12  is. The latter each comprise a longitudinal channel  16  capable of cooperating with one of the blocking members  13  and arranged opposite one of the holes  10  of the tenon  7  when the head  12  is inside said tenon  7 . 
         [0039]    Each hole  10  of the tenon  7  receives a blocking member  13  and is sized so as to enable the latter to go only partially beyond the outer face of the tenon  7  while retaining it so as to prevent it from completely emerging from the hole  10  and said tenon  7 . 
         [0040]    Said locking means  9  also comprise two notches  17  arranged on the mortise  8  of the rasp  2  arranged opposite one another along an axis substantially perpendicular to the direction of fitting of the assembly means  6 , each notch  17  being arranged opposite one of the holes  10  of the tenon  7  of the handle  1  when the latter is fitted in said mortise  8 . Each notch  17  has a generally rotationally cylindrical shape and is inclined with respect to the direction of fitting of the assembly means  6  and in the direction of the free end of the mortise  8 . In other words, the more one moves toward said free end, the narrower the notch  17  is. Said notches  17  are symmetrical with respect to the longitudinal axis of the mortise  8  and inclined in the opposite direction with respect to the inclination of the channel  16  associated with the head  12  of the slide  11 . Each notch  17  is capable of cooperating with one of the blocking members  13  in order to lock the assembly means  6 . 
         [0041]    In reference to  FIGS. 2 ,  3 ,  6  and  7 , when the tenon  7  of the handle  1  is fitted in the mortise  8  of the rasp  2 , each blocking member  13 , which is housed in a hole  10  of the tenon  7 , cooperates simultaneously with a channel  16  of the head  12  of the slide  11  and a notch  17  of the mortise  8 . It is thus understood that, in consideration of the inclination of the channel  16 , when the maneuvering lever  20  is closed, the slide  11  moves toward the interior of the rasp  2  to the “locked assembly” position, the blocking members  13  move away toward the outside of the tenon  7 , bearing on the associated notch  17 . In consideration of the inclination of the notches  17 , this action of the blocking members  13  has the effect of generating a clamping force one against the other of the respective contact faces  4 ,  5  of the handle  1  and the rasp  2 . This specific technical feature makes it possible to ensure the non-detachability of the handle  1 -rasp  2  assembly and in particular the suppression of any residual play between said handle  1  and rasp  2 . 
         [0042]    Conversely, in reference to  FIG. 5 , in order to be capable of releasing the handle  1 , it is necessary for the slide  11  to move toward the inside of the handle  1  to the “free assembly” position in order to enable the blocking members  13  to be completely inserted into the tenon  7  and the assembly means  6  and therefore the handle  1  to be decoupled. 
         [0043]    It is understood that the inclination of the channels  16  and that of the notches  17  may be inverted without going beyond the context of this invention. Thus, the head  12  will have two lateral faces  15  inclined with respect to the direction of fitting of the assembly means  6  and in the direction of the interior of the tenon  7 , and each notch  17  will be inclined with respect to the direction of fitting of the assembly means  6  and in the direction of the interior of the mortise  8 . With such a configuration, the slide  11  will then move toward the interior of the handle  1  so as to move from its “free assembly” position to its “locked assembly” position. 
         [0044]    In reference to  FIGS. 2 ,  4  and  6 , the assembly device  5  includes at least one push-member  18  mobile between two so-called useful positions, including, on the one hand, a position in which it cooperates with the slide  11  precisely so as to constrict it in the “locked assembly” position and, on the other hand, another position in which it places the slide  11  in the “free assembly” position so as to enable the handle  1  and the rasp  2  to be assembled or separated. 
         [0045]    Said push-member  18  is extensible, i.e. its length is variable so as to enable the constraint that it will exert on the slide  11  to be adjusted. Said adjustment makes it possible, on the one hand, to have the most suitable constraint value, and, on the other hand, to make up over time for the residual play in particular associated with wear of the parts constituting the assembly device  5 . To do this, the push-member  18  preferably has a screw-nut assembly with a differential pitch  19  so as to enable a very small variation in the length of said push-member  18  and consequently a very precise adjustment of the constraint applied. 
         [0046]    According to an alternative not shown, the push-member  18  has a resilient member, advantageously of the spring washer, commonly called “Belleville” washer, type. 
         [0047]    According to another alternative not shown, the push-member  18  has a screw-nut assembly with a differential pitch  19  associated with a resilient member, the screw-nut assembly with a differential pitch  19  enabling the precise adjustment and the resilient member making it possible to smooth the handling and compensate for wear. 
         [0048]    In reference to  FIGS. 1 ,  2 ,  4  and  6 , the assembly device  5  includes at least one maneuvering lever  20  pivoting with respect to the handle  1  about an axis substantially perpendicular to the longitudinal plane of symmetry of the handle  1 -rasp  2  assembly of the push-member  18  between at least two actuation positions, namely a “closed lever” position in which the maneuvering lever  20  extends substantially parallel and along the handle  1  to which it is articulated (cf.  FIGS. 1 ,  2  and  6 ) and an “open lever” position in which said maneuvering lever  20  forms a certain angle with said handle  1  (cf.  FIG. 4 ). The “closed lever” and “open lever” positions at least indirectly determine the “locked assembly” and “free assembly” positions of the slide  11 . 
         [0049]    For this, the push-member  18  is articulated at each of its ends to the slide  11  and to the maneuvering lever  20  about axes substantially parallel to the axis of rotation of said maneuvering lever  20  with respect to the handle  1  so that the rotation of the latter, by an action produced in particular by closing the hand on the handle  1 , drives the sliding of the slide  11  partially inside the tenon  7  in the direction of fitting of the assembly means  6  in order to block the handle  1  on the rasp  2 . The push-member  18  therefore acts as a connecting rod for transmitting the movement of the maneuvering lever  20  to the slide  11 . 
         [0050]    In addition, the maneuvering lever  20 -push-member  18 -slide  11  assembly is configured so as to be of the mechanical swivel type, i.e. the maneuvering lever  20  is blocked when the axis of articulation between the maneuvering lever  20  and the push-member  18  has gone beyond the point of alignment between the three axes of articulation and arrives at a stop, the three axes of articulation corresponding to the two axes of articulation of the push-member  18  on the slide  11  and on the maneuvering lever  20  and the axis of rotation of said maneuvering lever  20  on the handle  1 , said blocked position corresponding to the “closed lever” position of the maneuvering lever  20 . 
         [0051]    Thus, with such a configuration, when the maneuvering lever  20  is in the “closed lever” position, it remains, without the intervention of a user, in this position (cf.  FIG. 2 ). 
         [0052]    This special technical feature makes it possible to secure the assembly between the handle  1  and the rasp  2  while preventing any undesired opening of the maneuvering lever  20 . 
         [0053]    Among the various rasp models  2 , the shapes and sizes of the mortise  8  are relatively standardized, with barely over three or four mortise models, so that by manufacturing three or four handle models  1  with a tenon  7  corresponding to the different mortise models  8 , it is possible to provide, at a lower cost, a line of handles  1  compatible with all of the rasps  2  on the market. In fact, to render said handles  1  entirely compatible, it will merely be necessary to produce notches  17  on each rasp  2 . Each manufacturer of prostheses and associated rasps  2  can therefore, easily and inexpensively, render its rasps compatible with the handle  1  according to the invention. 
         [0054]    In addition, the handle  1  according to the invention may comprise only one hole  10 , one blocking member  13 , one channel  16  and one notch  17  without going beyond the present invention. 
         [0055]    Finally, the handle  1  comprises a hitting area  21  (shown in  FIGS. 1 and 2 ) at its free end so as to enable the surgeon to press each rasp into the medullary canal of the femur by tapping on said hitting area  21 . 
       INDUSTRIAL APPLICABILITY 
       [0056]    The handle  1  according to the invention applies more specifically to femoral raps  2  or the like, but it may also be used for any other tool in which any residual play is to be prohibited during its assembly with said handle  1 . 
         [0057]    Finally, it goes without saying that the examples of handles  1  according to the invention described above are merely specific illustrations, which in no way limit the invention.