FOOT ROTATION DEVICE

Description

[0001] The invention relates to a foot rotation device of an operating table according to the preamble of the first claim.

[0002] A foot rotation device is known, US 2017 / 0056234 A1, which is equipped with a foot rotation arranged on a pivotable boom, with a foot receiving cup having a heel-side mounting block and an extension extending therefrom into a rotation block provided with a locking device.

[0003] The rotation block allows the user to rotate the patient's foot or leg around its longitudinal axis during surgery and fix it in a desired position. In the familiar foot rotation device, this is achieved by a clamping screw that presses on the radius of a clamping ball mounted in the rotation block.

[0004] A disadvantage of this known state of the art is that the angle fixation depends on the clamping force of the clamping screw and therefore varies from user to user, potentially being too strong or too weak. This can lead to the rotation block slipping if the patient's foot or leg is severely twisted and the resulting torsional force is high. Another disadvantage is that, in order to increase the torsion during surgery, the user must loosen the clamping screw with one hand while simultaneously twisting and holding the patient's foot and leg with the other until the clamping screw is sufficiently tightened again. Situations where a strong user has tightened a clamping screw so much that another user cannot loosen it are also problematic, as this can significantly disrupt the surgical procedure.

[0005] Such a foot rotation device is known from DE 20 2016 101 587 U1.

[0006] The object of the invention is to provide a foot rotation device on an operating table that can be fixed in any desired position independently of manual clamping forces, and which should be easy and safe for everyone to operate.

[0007] The solution to this problem arises in conjunction with the features of the preamble of the first patent claim in connection with the technical features of its characterizing part.

[0008] Rotation is locked by pawls of the toothed mechanism, which engage with at least one locking gear. The angular locking, after pre-selection of the direction of rotation, is achieved by the positive engagement of one or more pre-tensioned locking levers with one or more locking gears. Such a locking mechanism remains angularly stable even under high torsional forces. If the torsion needs to be increased during surgery, the user simply needs to rotate the patient's foot further with one hand to twist the entire leg. The locking gear then automatically re-locks the position without the need to operate a clamping screw that frictionally engages a clamping ball.

[0009] Further advantageous embodiments of the subject matter of the invention are set out in the following dependent claims.

[0010] According to a particularly preferred embodiment of the invention, two locking gears with radially opposed locking notches are arranged slightly apart from each other on a common shaft in the rotating block, which is connected to the extension and between which a switching cam of the actuating rotary handle extends, wherein two locking levers with pawls are pivotably mounted in the rotating block about axes parallel to the axis of rotation of the shaft, which rest with control cams on the switching cam of the actuating rotary handle, wherein, depending on the angle of rotation of the rotary handle, at least one pawl engages in or is lifted from its associated locking gear.Locking or releasing the rotational movement in one of the two possible directions is achieved simply by switching the rotary handle, since depending on the angle of rotation, one or both pawls engage in or are disengaged from their corresponding locking gear.

[0011] A particularly advantageous embodiment of the invention is one in which the switching cam extends between the locking levers, which in turn have control cams that rest elastically on a cam track of the switching cam by a spring. The switching cam has a circular cylindrical basic shape, with the cam track extending approximately over half the circumference from a circular cylindrical section with a smaller diameter than that of the basic shape, forming an inner track. Curved cam tracks, extending to the larger diameter of the basic shape, adjoin this inner track on both sides, and the cam track is completed by a section with the diameter of the basic shape, forming an outer track.

[0012] In conjunction with this asymmetrical design of the cam track and the arrangement of the control cams of the locking levers running along it, four switching functions can be realized, in which the control cams either simultaneously contact the inner track or simultaneously the outer track, or alternately one on the outer track and one on the inner track, whereby when simultaneously on the inner track a complete locking of the rotation occurs, when simultaneously on the outer track a complete freewheeling on both sides is possible, or with a position of the actuating rotary handle rotated by + or - 90° with one control cam on the inner track and one control cam on the outer track a left-sided freewheeling and a right-sided locking or a right-sided freewheeling with a left-sided locking can be set.

[0013] The inventive arrangement of the cam position on the locking levers and the arrangement of the control cams on the cam track of the switching cam, which deviates from a radial contact, therefore provides four different switching functions.

[0014] An embodiment of the invention is described in more detail below with reference to the drawings. The drawings show: Fig. 1 a foot rotation device of an operating table in a spatial view, Fig. 2 an exploded view of the foot rotation device, Figs. 3-6 sectional views of the toothed gear in different switching positions, Figs. 7-10 sectional top views of the toothed gear according to the Fig. 3 - 6 , Fig. 11 an enlarged view of the left locking lever, Fig. 12 an enlarged view of the right locking lever, Fig. 13 an enlarged view of the left locking gear, and Fig. 14 an enlarged view of the right locking gear.

[0015] The foot rotation 1 of a foot rotation device of an operating table is arranged on a pivotable arm, to which it is height-adjustably fixed via a profile tube 25. It also has a handwheel 24 to move a foot support 2, containing a patient's foot or leg during surgery, into an extended position. Below the foot support 2, in the heel-side area, a mounting block 3 is arranged, into which a locking block 23 of the rotation block 4 extends. A projection 5 engages this projection, acting as a joint, and extends into the housing 20 of the rotation block 4, where it is connected to the shaft 10 mounted therein.

[0016] The rotating block 4 is designed as a toothed lock for two directions of rotation and for this purpose has two locking gears 7; 8 with radially opposing locking notches 9, wherein the two locking gears 7; 8 are arranged apart from each other on the common shaft 10, between which a switching cam 11 of the actuating rotary handle 6 extends, wherein the switching cam 11 has a circular cylindrical basic shape and is equipped with an inner track with a reduced diameter extending over approximately half of its circumference and adjoining curved tracks, except for the larger diameter of the outer track, to which the outer track as the last section of the entire cam track 18 adjoins over the remaining circumference.

[0017] Above the two locking gears 7; 8, two locking levers 12; 13 are arranged on locking lever shafts 26; 27 parallel to the shaft 10. These locking levers have pawls 14; 15 that engage with the locking gears 7; 8 or can be positioned away from them. For this purpose, they are equipped with control cams 16; 17 that rest on the cam track 18 of the switching cam 11. The two control cams 16; 17 rest opposite each other on the cam track 18, but not radially, rather offset from a central plane through the switching cam 11. Depending on the rotation angle of the actuating rotary handle 6, they either rest simultaneously on the inner track of the switching cam 11 or on its outer track, or either one control cam 16; 17 rests on the inner track and the other on the outer track. 16 on the outer track of the cam track 18, so that a total of four switching positions are created.

[0018] The Figures 3 and 7Figures 11 show the position of the shift cam 11 in two views, in which, under a rotation angle of the actuating rotary handle 6 of 0° with complete free movement of the shaft (10) on both sides, both pawls 14; 15 are lifted from the locking gears 7; 8. Figures 5 and 9 Figures 1 and 2 show a position of the switching cam 11 in two views with complete double-sided locking of the shaft at 180° of the rotation angle of the actuating rotary handle 6, in which the control cams 16; 17 both rest on the inner track of the cam track 18 of the switching cam 11, so that the locking levers 12; 13 pivot about the locking lever axes 26; 27 and engage with their pawls 14; 15 in the locking gears 7; 8 and thus create a double-sided rotary locking.

[0019] The Figures 4 and 8Positions 6 and 10, respectively, represent six switching positions when the operating handle is rotated by 90° and 270°, respectively. In these positions, either the clockwise rotation of the locking gear 7 or the counterclockwise rotation of the locking gear 8, and thus of the shaft 10, is blocked. The respective pawls 14 and 15 can briefly disengage over the shallower flanks of the locking notches 9 when rotating in the opposite direction. A spring 19 holds the pawls 14 and 15 permanently biased towards the locking gears 7 and 8, ensuring a positive engagement in the blocked direction of rotation at all times.

Claims

1. Foot rotation device of an operating table, comprising a foot rotator (1) which is arranged on a pivotable boom and has a foot receiving shell (2) with a heel-side fastening block (3), and the rotation device comprising a projection (5) extending therefrom into a rotation block (4) provided with a locking device, the projection (5) being designed as a joint piece and the locking device of the rotation block (4) being designed as a ratchet mechanism (28) for two directions of rotation and the rotation block (4) having an actuating rotary handle (6) and at least one direction of rotation being blocked or released depending on the angle of rotation thereof, characterized in that two ratchet wheels (7; 8), having radial locking notches (9) formed opposite one another, are arranged in the rotation block (4) so as to be slightly spaced apart on a common shaft (10) which is connected to the projection (5), a switching cam (11) of the actuating rotary handle (6) extends between the ratchet wheels (7; 8), and two locking levers (12; 13) having locking pawls (14; 15) are mounted in the rotation block (4) so as to be pivotable about locking lever pins (26; 27) parallel to the axis of rotation of the shaft (10), which locking levers have control cams (16; 17) with which they permanently rest on a cam track (18) of the switching cam (11) and, depending on the angle of rotation thereof, one or both locking pawls (14; 15) engage in their associated ratchet wheel (7; 8) or are detached from it.

2. Foot rotation device according to claim 1, characterized in that the switching cam (11) extends between the locking levers (12; 13) which have control cams (16; 17) which rest in a resiliently preloaded manner on a cam track (18) of the switching cam (11), which has a circular-cylindrical basic shape, the cam track (18) being composed, over approximately half of the circumference, of a circular-cylindrical portion having a smaller diameter than that of the basic shape and, adjacent thereto, curved-in curved paths up to the larger diameter as the inner track and of a sub piece having the diameter of the basic shape as the outer track.

3. Foot rotation device according to claim 2, characterized in that the control cams (16; 17) rest on the cam path (18) opposite one another and laterally offset in parallel from a central plane by the control cam (9) and rest either simultaneously on the inner track or on the outer track or alternately on one of the two tracks, and four switching positions are generated with an angular distance of 90° from one another, with complete bilateral freewheeling of the shaft (10) at 0°, complete bilateral locking of the shaft (10) at 180°, or left-hand freewheeling with right-hand locking at 90° or right-hand freewheeling with left-hand locking at 270°.