Abstract:
The invention relates to a leg support arrangement for operating tables comprising two leg supports, connected to a base element of an operating table such that, the above are adjustable between a base position, lying adjacent to each other parallel to the longitudinal mid-axis of the operating table and a spread position with a separation from the longitudinal mid-axis, whereby each leg support is connected to the base element by means of a parallelogram joint, the joint axes ( 36, 52, 44, 54 ) of which are arranged perpendicular to the plane of the base element.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   Applicants hereby claim foreign priority benefits under 35 U.S.C. § 119 of PCT Patent Application No. PCT/EP2003/010844 filed Sep. 30, 2003 and German Patent Application No. 102 53 906.5 filed Nov. 19, 2002, the disclosures of which are herein incorporated by reference. 
   BACKGROUND OF THE INVENTION 
   1. Technical Field 
   The invention concerns a leg support arrangement for operating tables with two leg supports connected with a base element of an operating table so that they are adjustable between a fundamental position in which they lie next to one another parallel to the longitudinal middle axis of the operating table and a spread position in which they are spaced from the longitudinal middle axis of the operating table. 
   2. Background Art 
   In all operating procedures in which the operator moves into the foot-end of the operation field the legs of the patient lying on the operating table must be spread. In customary operating tables the leg supports are linked to the base element by means of spreading joints for pivotal movement about axes perpendicular to the operating table support surface, so that the leg supports can be pivoted about the spreading joints near the hips to provide a free space in the middle region between the leg supports. Although as a rule recesses are provided on the edges of the leg supports facing one another near the base element, the free space existing between the spread leg supports is not sufficient for all applications. 
   SUMMARY OF THE INVENTION 
   The invention has as its object the provision of a leg support arrangement of the previously mentioned kind in which a sufficient free space can be achieved between the leg supports. 
   This object is solved in accordance with the invention in that each leg support is connected with the base element by means of a parallelogram joint whose pivot axes are arranged perpendicular to the plane of the operating table support. 
   In the case of the inventive solution each leg support, by means of the parallelogram joint, is displaceable parallel to itself laterally outwardly. Thereby there exists between the leg supports an essentially larger free space than would be possible with a similar spreading of the patient&#39;s legs with the customary leg supports which are movable about spreading joints near the hips. 
   In many applications not only the legs of the patient have to be spread apart but also the lower leg has to be bent. For this, leg support arrangements are known in which each leg support has an upper leg support and a lower leg support each of which is pivotal by a folding joint about a horizontal axis relative to the base element and relative to one another, as for example shown in U.S. Pat. No. 6,276,012 B2. In accordance with the invention, for such a leg support arrangement it is proposed that each upper leg support is connected to a connecting piece by two links forming the parallelogram joint, to which connecting piece the first ends of the links are joined and which connecting piece is connected to the base element for pivotal movement about the folding axis for the upper leg support, and the second ends of the links are pivotally connected to the upper leg support to which the folding joint for the lower leg support is connected. 
   The inventive solution has the advantage that both the folding axes for the upper leg supports as well as the folding axes for the lower leg supports both maintain their orientation in space when the leg supports are moved away from or toward one another. It is therefore assured that the lower leg supports upon angularly adjusting the leg supports, that is upon the upward pivoting of the upper leg support and the folding down of the lower leg support, these do not become inclined. Thereby a sliding of the lower leg laterally from the lower leg support is inhibited. 
   In a preferred embodiment the upper leg support is not formed as one piece but instead includes a connecting member and an upper leg plate connected to the connecting member in a releasable fashion with the links being pivotally connected to the connecting member and with the folding joint for the lower leg support being formed on the connecting member. The lower leg support also preferably includes a lower leg strut and a lower leg support plate releasably connected to the strut. The connecting member together with the links of the parallelogram joint and the lower leg strut thereby form a carrier structure for the leg plates of the upper leg support and the lower leg support which plates can be exchanged for others if needed. 
   To be able to further open the space between the leg supports it is advantageous if the lower leg strut is connected with a joint arm by means of a spreading joint, which joint arm is connected to the connecting member by means of the folding joint for the lower leg support, with the axis of the spreading joint being perpendicular to the axis of the folding joint and perpendicular to the plane of the lower leg support plate. The sequence of the joint arrangement—as seen in going from the base element to the lower leg support—in connection with the parallel guiding of the upper leg support assures that the lower leg support plates even in the case of pivoted and spread apart upper leg supports always pivot about a horizontal folding axis and thereby foreclose a tilting of the lower leg support plates about a longitudinal axis. 
   Preferably the connecting piece is insertable into a receiver fixed to the operating table, which receiver is a part of the folding hinge for the upper leg support. Therefore the leg plates can be quickly and easily connected to the base element or removed from it and, as the case may be, may be exchanged for other leg supports. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The following description along with the accompanying drawings explains the invention by way of an exemplary embodiment. The drawings are: 
       FIG. 1  is a perspective view at an angle from above onto a leg support arrangement connected with a base element of an operating table with the leg supports in closed position, 
       FIG. 2  is a plan view of the arrangement according to  FIG. 1  with the leg supports in spread position, 
       FIG. 3  is a view of the leg support arrangement from the foot-end with angularly adjusted leg supports, 
       FIG. 4  is a perspective view of the arrangement illustrated in  FIG. 1  with one leg support swung entirely downwardly and one leg support with a downwardly folded lower leg support, 
       FIG. 5  is a perspective illustration of the carrier structure of one leg support, 
       FIG. 6  is a side view of the structure illustrated in  FIG. 5  taken in the direction of the arrow A in  FIG. 5  with mounted plates, and 
       FIG. 7  is a section taken through the carrier structure along the line VII-VII in  FIG. 5 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Illustrated in  FIG. 1  is a portion of a patient support surface or operating table plate with a base element  10 , which element is usually connected to or connectable to the column head of a support column of an operating table. Connected with the base element  10  is a leg support arrangement  12  having two leg supports  14 . Each leg support  14  has an upper leg support  16  and a lower leg support  18 . The upper leg supports  16  are connected with the base element  10  and lower leg supports  18  are connected with the associated upper leg supports  16  by way of joints so that the upper leg supports  16  and the lower leg supports  18  can be adjusted to different positions.  FIG. 1  shows the leg supports  12  and their parts  16 ,  18  in a fundamental position in which the leg supports  12  are oriented parallel to the longitudinal middle axis  20  of the operating table plate and lie close to one another.  FIG. 2  shows the arrangement according to  FIG. 1  in a spread position, in which the upper leg supports  16  have been shifted in the direction of the arrow B parallel to themselves outwardly, while the lower leg supports  18  each have been pivoted in the direction of the arrow C outwardly relative to the associated upper leg supports  16  about a spreading axis perpendicular to the picture plane. 
     FIG. 3  shows a position in which the upper leg supports  16  of both legs supports  14  have been folded about a horizontal folding axis  22  perpendicularly upwardly; with the left upper leg support  16  in  FIG. 3  simultaneously having been shifted outwardly in the direction of the arrows B. The lower leg supports  18  of both leg supports  14  have each been folded about a horizontal folding axis with respect to the associated upper leg support  16  into the horizontal position, with the left lower leg support  18  in  FIG. 3  additionally having been pivoted about its spreading axis outwardly. 
   Finally,  FIG. 4  shows a position in which the left leg support in  FIG. 4  in its entirety is pivoted downwardly about the horizontal folding axis  22 , while in the case of the right leg support  14  only the lower leg support  18  is folded so as to extend vertically downwardly. 
   The construction of the carrier structure of each leg support with its joints, which make possible the previously illustrated movements of the upper leg supports and lower leg supports will now be explained with reference to  FIGS. 5 to 7 . 
   In  FIG. 5  is seen a connecting piece indicated generally at  24  having a joint fork  26  and a shank  28  rigidly fixed to the joint fork. By means of this shank, the connecting piece  24  can be inserted into a receiver  30  which is pivotally connected to the base element  10  for movement about the horizontal folding axis  22 . The receiver  30  can be clamped in a desired pivotal position about the axis  22  by a clamping mechanism  32 , which in itself is known and therefore not illustrated in more detail. The connecting piece  24  can be anchored in the receiver  30  in a non-illustrated way. The folding joint along with the folding axis  22  could also be integrated into the connecting piece  24 . 
   A first link  34  is pivotally supported in the joint fork  26  of the connecting piece  24  for movement about a pivot axis  36 , and with the help of an eccentric clamping mechanism  37 , known in itself, with a tensioning lever  38  and toothed disks  40 , can be fixed in a desired pivotal position about the axis  36 . The link  34  at its other end is pivotally connected with a connecting member  42  for movement about a joint axis  44 . The connecting member  42  is plate-shaped and serves for holding an upper leg plate  46 , which can be fastened to the connecting member  42  by non-illustrated screws passing through bores  48  in the connecting member  42 . The connecting member  42  and the upper leg plate  46  together form the upper leg support  16 . The joint fork  26  and the connecting member  42  are further connected with one another by a second link  50 , which link  50  at one end is pivotally connected to the joint fork  28  for movement about an axis  52  and at its other end is pivotally connected to the connecting member  42  for movement about an axis  54 . The two links  34  and  50  form with their joint axes  36 ,  52  and  44 ,  54  a parallelogram joint, by means of which the connecting member  42  and with it the upper leg plate  46  can be adjusted parallel to itself without it changing its orientation in space. 
   At the end of the connecting member  42  remote from the connecting piece  24  is a joint arm  56  which by means of a folding joint  58  is pivotally supported for movement about a horizontal folding axis  60 . The joint arm  56  can with the help of an eccentric clamping mechanism  61 , operable by a clamping lever  62 , be fixed in a desired folded position. The eccentric clamping mechanism  61  is made in a way similar to that of the clamping mechanism  37  intended for fixing the first link  34 . 
   The joint arm  56  has a joint fork  64  which forms a spreading joint  66  for a lower leg strut  68 . The lower leg strut  68  serves for holding a lower leg plate  70 . The spreading axis  72  of the spreading joint  66  is arranged perpendicular to the folding axis  60  and to the plane of the lower leg plate  70 . The spreading joint  66  can be clamped by means of an eccentric clamping mechanism  74  which like the previously mentioned clamping mechanisms includes a clamping lever  76  and toothed disks  78 . 
   The carrier structure illustrated in  FIGS. 5 to 7  is completed by the upper leg plate  46  and the lower leg plate  70  as is indicated in  FIG. 6 . 
   Each upper leg support  16 , or the leg support  14  in its entirety, can first of all be pivoted upwardly and downwardly about the folding axis  22  relative to the base element  10 . Further the upper leg support  16 , or the leg support in its entirety, with the help parallelogram joints  34 ,  40 ,  36 ,  52 ,  44 ,  54  can be displaced laterally relative to the base element  10 , as is illustrated in  FIG. 2 . The lower leg support  18  can on one hand be pivoted relative to the upper leg support  16  about the horizontal folding axis  60  ( FIGS. 3 and 4 ) and on the other hand can be rotated about the spreading axis  72  ( FIG. 2 ). Because of the fact that the upper leg support  18  is adjustable by means of the parallelogram joint the two folding axes  22  and  60  always remain parallel to one another and horizontal. As a result of this the lower leg support in all of its possible positions remains stable with reference to its longitudinal middle axis, that is it is not tilted laterally. Therefore it is avoided that the leg of a patient can slip off of the lower leg support, which would require it additionally having to be fixed in place. From a comparison of  FIGS. 1 and 2  it will further be seen immediately that by outward pivoting of the leg supports about vertical spreading axes lying at the connecting spotted between the base element  10  and the upper leg supports  16  only a relatively small free space can be achieved between the two leg supports, whereas the lateral shifting of the leg supports with the help of the associated parallelogram joints provides a greater free space. 
   While the present invention has been illustrated and described with respect to a particular embodiment thereof, it should be appreciated by those of ordinary skill in the art that various modifications to this invention may be made without departing from the spirit and scope of the present invention.