JPH0226197B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a joint stand, and more particularly to a joint stand in which shaft bolts cross and are pivotally connected to each other by a fixable central joint and support ball joints at their ends. at least two arms lockable with the central joint by means of a tensioning mechanism and a locking mechanism, the locking mechanism acting on the ball joint and disposed within the arms. It relates to a joint stand which has a push rod which can move a part with two inclined abutment surfaces by means of a relative movement with respect to one another.

Such a joint stand is used by a surgeon, for example, as a retractor. A joint stand with a central joint and two ball joints has one at each arbitrary position.
It can be fixed with two handles.

Such a joint stand is already known from US Pat. No. 3,240,516. The axial bolt of the central joint of this stand has two conical casings, which act on the corresponding inclined surfaces at the ends of the push rods. In actuation of the tensioning lever with eccentric plate, the housings are pulled together and the push rod is pushed outwards. The tension forces that must be applied due to internal friction are very high and the central joint must be dimensioned accordingly. The wedge face is sloped for self-locking and stopping, so that it must be well lubricated but is difficult to sterilize. The axial force generated during tension tends to tilt the push rod within the arm tube.

Another joint stand of this type is described in German Published Patent Application No. 2717828. In this stand, the wedge-shaped tensioning elements are pressed apart by pressure rollers, the pressure being transmitted to the push rod. The central joint consists of several individual parts, which are expensive to manufacture and difficult to install. This is particularly inconvenient during sterilization. If the fitting is not disassembled, there is no guarantee of satisfactory sterilization. On the other hand, when disassembled, assembly is difficult and time consuming.

The object of the invention is to avoid the mentioned disadvantages and to be able to operate with low consumption of forces, disassembly and assembly are also free of problems regarding auxiliary personnel, allows simple and inexpensive manufacture, and has a higher load capacity than known stands. The purpose is to form a high joint stand.

The solution to this problem, according to the invention, is that the abutment surfaces are arranged inside two cavities, in which a ball is attached which acts on the push rod, and at least one of said cavities is connected to an axial bolt. The second cavity is arranged in a case which can be moved in the axial direction above, and the second cavity is created by being arranged in a case which can be fastened directly to the axle bolt or to the axle bolt.

With this structure, the force to be transmitted by the joint stand can be increased. Its individual parts are more suitable for mass production and assembly is possible without problems after sterilization.

A major drawback of the known stand is that the arm tilts and the ball joint flexes as soon as the tensioning mechanism is released. Instruments or instruments fixed to the ball joint may thereby be damaged in the event of a collision. To avoid this, in one embodiment of the invention a central joint with a compression spring is provided to maintain an adjustable locking force upon release of the tensioning mechanism.

Embodiments of the present invention will be described in detail below with reference to the drawings.

The joint stand has two arms 1, 2 which are pivotally connected to each other by a central joint 3. At the ends of the arms there are movably mounted joint heads 4, 5 each having a threaded bolt 21. By means of a tensioning mechanism in the form of a hand lever 6 or a wheel wheel, the central joint 3 is also connected to both joint heads 4,
5 are also locked or released together. This is caused by the axle bolt 7 placed perpendicular to the arm;
A hand lever 6 is screwed onto the end of the axial bolt and is moved axially in relation to the arms 1,2. A case 8 is fitted onto the shaft bolt 7, the front side of which is in contact with the adjacent radial surface of the hand lever 6. The axle bolt 7 is provided with a spherical recess 9 in the region of the arm 1 . This recess 9 is curved in cross section and the shape of the ball 10 is adapted so that this appears from FIGS. 5 and 6. A similar spherical recess 11 is also present in the case 8, which likewise cooperates with a ball 12 (FIGS. 5 and 7). There is a push bolt 13 mounted inside the arm tube 22 relative to the ball 10, which is connected to the inner part 14 of the push rod. ball 1
0 and 12 are held slightly movable within the bore of the arm tube 22 with virtually no radial play. The push bolt 13 and the push rod inner part 14 may consist of separate parts or of one piece. The push rod outer part 15 connects to the push rod inner part 1 via a pressure spring 16.
4. Push rod outer part 15
is attached to a ball socket 17 in a ball case 18, and the ball case 18 is mounted so as to be rotatable around the axis of the arm. The ball socket 17 presses against the ball retaining bolt 20 which can pivot through approximately 180° due to the groove 58. The interior of arm 2 is constructed as in arm 1, so that identical parts have the same reference numerals.

According to FIG. 4, the central joint 3 has two discs 24,
It has 25. These discs have a front surface of 26
and these front surfaces form an inherent friction surface. In order to maintain a good mutual centering of the two disks 24, 25, there is a groove on one side and a corresponding ring-shaped shoulder 28 on the other side. In addition, a thin friction ring, for example made of hard rubber, can also be arranged between the two discs, the latter being centered by the annular shoulder 28. Both disks 24, 25 are penetrated by the shaft bolt 7 in the central hole 29. Each disk 24, 25
is provided with a lens-shaped cutout 27 on its outside, the radius of which corresponds to the radius of the arms 1, 2. These notches 27 are used to release the arm tube 22 from receiving it.

At its end remote from the hand lever 6, the axle bolt 7 has a non-circular appearance, in particular an oval shape (see FIG. 6), which engages a correspondingly formed transverse hole in the arm tube 22. It is mounted so that it fits and does not rotate, but can move within this lateral hole. Also, a part of the case 8 has an appearance different from a circular one, in particular an oval shape (see FIG. 7), which protrudes into the corresponding lateral hole of the arranged arm tube 22 and does not rotate therein, but in the axial direction. It is maintained so that it can be moved.

A joint head 4 is provided in the arm tube 22 of the first arm 1.
A tightening screw 30 that cooperates with a tightening jaw 31 is provided at an end opposite to the tightening jaw 31.
When the tightening screw 30 is screwed in, it can be pressed against the shaft bolt 7.

At its end remote from the joint head 5, the second arm has a first tightening screw 35 acting on the tensioning case 8 and a second tightening screw 36 acting on the axle bolt 7. The first tightening screw 35 cooperates with a tightening jaw 37, which is pressed against the sleeve of the tensioning case 8 when the tightening screw 35 is screwed into the arm tube 22. The clamping screw 36 passes through the central hole of the clamping screw 35 and is pressed against the axle bolt 7 through an opening 39 in the tensioning case 8 with a clamping jaw 38 when the clamping screw 36 is screwed.

The joint stand described above operates as follows.
That is, both joint heads 4 and 5 in the positions sometimes simultaneously occupied by rotation of the hand lever 6.
The locking of the central joint 3 as well as the locking of the central joint 3 can be achieved. During tightening, that is, when the hand lever 6 is screwed into the thread of the shaft bolt 7, the shaft bolt 7 is pulled in the direction of arrow A. Thereby, the ball 10 is pushed outward along the inclined curved notch 9 in the direction of arrow B, and this movement is caused by the pushing rod 14.
and 15 to the ball socket 17 and forces it onto the ball retainer bolt 20, so that it is locked in its position by a frictional closure. The hand lever 6 is at the same time also pressed against the front side of the tensioning case 8 and moves it opposite to the direction A, so that the ball 12 is moved into the inclined curved notch 1.
1, it is moved in the direction of arrow C within the arm tube 22. This movement is also transmitted via the push rods 14, 15 placed inside the arm 2 to the ball socket 17 and blocks the ball stud 20 of this arm 2 as well as its ball joint.

As a result of the tightening movement of the hand lever 6, the two discs 24, 25 of the central joint 3 are also pressed together, so that their front faces 26 are protected against rotation by a frictional closure. There again, all three joints are locked by one hand lever 6. In order to release all three joints, they are also forced to rotate the hand lever 6 in the opposite direction.

It also has the possibility of selectively releasing the joint of one arm while retaining the ball retainer bolt of the other arm in its locked position. If the ball retaining bolt 20 of arm 1 has to be blocked,
This is done by screwing in the tightening screw 30.
This tightening screw 30 is then
is pressed against the axial bolt 7 and prevents it from being able to move axially in relation to the arm 1. The clamping force is then maintained and the ball bolt 20 of arm 1 cannot move, while the other two joints are released.

When the tightening screw 36 is screwed in, it presses against the axle bolt 7 via its tightening jaw 38 and prevents it from being able to move in the axial direction. It is both discs 24, 2 of central joint 3.
This causes a blockage in position 5. On the other hand, the tightening of the tightening screw 35 makes it possible to press the tightening jaw on the tensioning case 8, so that it cannot move in the axial direction and the ball 12 is accordingly held in its tensioned position, As a result, the ball retaining bolt 20 of the arm 2 is fixed in that position.

FIG. 8 shows a variant embodiment in which the ends of both arms can be provided with joint heads which are secured and released by tension levers 6. As in the embodiment according to FIGS. 1 to 7, identical parts have been provided with the same reference symbols. What differs is the construction of the shaft bolt 7, which on the side diametrically opposite to the curved recess 9 has a further curved recess 9 which cooperates with a ball 10. In addition to the curved cutout 11, the tension case 8 also includes another diametrically opposite curved cutout 11, against which the ball 12 rests. The ball acts on the push rod 14 in a manner similar to that already described, and causes the push rod 1 to
4 fixes in position a ball retaining bolt 21, not shown in FIG. 8, which is to be attached to the end of the arm during movement in the direction of arrow E.

Instead of a groove-like cutout, the axle bolt 7 and tension case 8 also each have a rotating cross-section curved appearance. The fixation of the axle bolt 7 in relation to the arm tube 22 can also be achieved instead of the shape according to FIG. 6 by a hexagonal or other non-circular profile or wedge.

A compression spring 41 is arranged between the tensioning lever 6 and the front side of the case 8 in order to avoid uncontrollable movements of the arm under weight loading when the tensioning lever 6 is released. This compression spring is located in a spring case 41 that is connected non-rotatably to the axle bolt 7 or to the case 8. By means of a disk-shaped screw socket 42 which can be inserted into the spring case,
The compressive force of spring 41 is adjusted. The curved recesses 9, 11 are thereby pressed on the released hand lever 6 by a predetermined force on the balls 10, 12 and with it via the push rod onto the brake lug 17 of the joint head and its As a result, it is achieved that the ball retainer bolt 21 is brought to a new position after overcoming a certain force. Also, both discs 24,
25 are brought into contact with each other in a frictionally tight manner due to compression.

In a modified embodiment, instead of the balls 10, 12, cylinder rollers and square tubes can be used, or the push rod can be formed directly into a spherical shape. The curved surfaces 9, 11 can also be formed in the form of a linear slope, the slope being inclined with respect to the longitudinal axis of the shaft bolt 7.

In the variant embodiment according to FIGS. 9 to 11, the housing 8 is likewise provided with one or two diametrically opposed curved recesses 11. The push bolt 14 or push rod end rests against the ball 12 or 10. In contrast to the embodiment according to FIGS. 1 to 8, the balls 12 and 10 here have a smaller diameter than the bore of the arm tube 22. In contrast to the embodiment according to FIGS. The front side of the push bolt 14 or the end of the push rod, remote from the ball 12, has a conical structure 44 which is implemented as a notch and as a point. The central angle β of this conical structure 44 is such that the wedge surface 45
selected according to the When the inclination angle α of the wedge surface 45 is selected to be 35°, for example, the central angle β of the cone 44
will be 110°. As a result, when the case 8 is moved in the direction of the arrow F, a true rolling movement of the ball 12 occurs. This reduces friction and allows greater clamping or holding forces to be utilized at the end of the arm. The straight line of the conical sleeve along which the ball 12 rolls on the pressure bolt 14 and the straight line along which the ball 12 also rolls and the wedge surface 45 should be chosen to run parallel thereto, or in such a way that they run at least approximately parallel to it. The highly conical structure has the advantage that it produces concentric guidance of the balls. A similar structure can also be chosen in the curved surface 9 of the axle bolt 7, for example in the arms arranged on both sides according to FIG. 8, so that all four curved surfaces and balls are correspondingly formed.

In the embodiment according to FIGS. 12 and 13, the recess 9 is not provided directly on the axle bolt 7, but rather is arranged in another housing 46. In the embodiment according to FIGS. This is the screw 47 at the end of the shaft bolt 7 facing the hand lever 6.
is screwed into the Both cases 8, 46 are oval-shaped and pass through corresponding transverse holes at the ends of the arms 1, 2. The arms therefore do not rotate on the cases 8, 46, but are axially movable on these cases.

The end of the arm has a square cross section 48 which cooperates with a freely rotatable friction disk 49 arranged concentrically on the shaft bolt 7, the friction disk being defined as a specific friction surface. It has protruding ring surfaces on both sides. The outer arm extension with push rod and joint head is not shown in FIGS. 12 and 13.

If the clamping force of the joint head is changed, both bushings 8, 46 and the corresponding pushrod inner part 14 are slightly exchanged. For example, an arm fixed to the stand leg can cooperate with one liner,
The liner has a cutout with a steeply sloped abutment surface compared to a cutout in the second liner defined for example with respect to the support arm. When tightening the hand lever, the arm supported on the stand at that time is locked more strongly than the support arm. The clamping force and the clamping method are likewise influenced by the corresponding selection of the shape and inclination of the abutment surface.

In addition, the joint stand shown in FIGS.
A compression spring 41 is provided which is pressed against the disc 51 and rests against the hand lever at the inner end of the screw 52. The spring case 40 is supported on the front side of the case 8, which is freely movable on the axle bolt 7.

Due to the compression of the spring 41 the hand lever 6 is moved away and the axle bolt (the hand lever end of which is provided with a slit 53) is further moved away from the second liner 46.
screwed into. The lock nut 54 is then fitted so that the adjusted tension cannot be changed.

In contrast to the embodiments according to FIGS. 1 and 8, the hand lever 6 does not press directly against the spring 41 and therefore has to overcome the spring force during tightening. The hand lever is attached to case 8 via the spring case.
act directly on the top and as a result requires less force consumption than when tightening. This also cooperates with practically negligible friction, so that the joint stand can be loaded to a greater extent than known joint stands.

This relationship is shown schematically in FIGS. 14 and 15. FIG. 14 shows the constant adjustment of the tension on the released or disengaged hand lever 6. FIG. In FIG. 14, hand lever 6 is tensioned and spring 41 is partially released.

Depending on the purpose, a base plate 55 having a give key 56 is arranged between the spring case 40 and the tension lever 6. The give key 56 enters into a longitudinal groove 57 of the axle bolt 7, so that the base plate 55 is mounted so that it does not rotate but can be moved axially on the axle bolt 7. Correspondingly, the tensioning lever 6 can be released and tensioned as often as desired, without its rotary movement resulting in an adjustment of the tension. Also, opposite rocking of the arm has no effect on the tension.

Disassembly and assembly are simple and problem-free, so that an assistant can easily sterilize the coupling stand.

In order to avoid corrosion of drive-critical parts in each case, the necessary working properties can be generated by surface treatment (for example "Tenifer" treatment).

In addition to its use in surgery, it can also be used to support instruments and tools in industry, labor, etc.

In still other embodiments, the adjustment nut 54 (FIGS. 12 and 13) may be replaced by a round nut for continuous adjustment. axis 4
6 is not screwed onto the shaft bolt 7 in that case. Alternatively, the housing 46 and the axle bolt 7 may be connected with a longitudinal wedge that protects them against rotation.

To summarize the invention, the joint stand comprises two relatively swingable arms 1, 2 with movable joint heads 4, 5 at their ends. A tensioning lever 6 locks and releases the central joint 3 and the joint heads 4, 5 at the same time. In order to increase the force to be transmitted by the joint stand, there is an axial bolt 7 which presses against the ball 10 via the tension curve 9 and thereby links 14, 15, 15 in the first arm 1. The joint head 4 is secured via 17 with a frictional closure. The case 8 on the shaft bolt 7 is connected to the second case through the curved surface 11.
It acts on the ball 12 of the arm 2 and transmits the resulting movement during tension to the joint head 5 of this arm 2. Both disks 24, 2 of the central joint 3 simultaneously when tensioned.
5 are pressed together. Therefore, according to the invention, the recess is formed in the form of a groove with a spherical cross section, and the ball is placed between the axial bolt and the pressure bolt to be moved, so that the axial bolt is moved in the axial direction. At this time, the ball rotates smoothly in the groove-shaped recess and is raised or lowered only in the axial direction of the pressing rod. Therefore, the forces acting on the axial bolt, the ball and the pressure bolt are always in the axial direction in relation to the pressure bolt to be moved, so that the actuation is good and does not require large forces. The joint stand is suitable for use by a surgeon, for example as a retractor. A compression spring 41 can be provided, so that the arm does not tilt immediately upon release of the tensioning lever.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of the joint stand, FIG. 2 is a sectional view taken along the line - in FIG. 1,
Fig. 3 is a plan view showing the disc of the central joint of the joint stand according to Fig. 1, Fig. 4 is a side view showing both discs of the central joint, Fig. 5 is a diagram showing the shaft bolt including the case, and Fig. 6. is a cross-sectional view of the shaft bolt along the line - of Fig. 5, Fig. 7 is a cross-sectional view of the shaft bolt and the case along the line - of Fig. 5, and Fig. 8 shows that each arm is provided with a joint head on both sides. FIG. 9 is a schematic diagram showing the case on the shaft bolt of the embodiment with rollable balls, not in the tightening position; FIG. 11 is a schematic diagram similar to FIG. 9 in the tightened position, FIG. 12 is a partially sectional side view showing the central joint of another variant, and FIG. 13 is the central view of FIG. 12. Top view of the joint, Figures 14 and 1
FIG. 5 is a schematic diagram showing the constant adjustment of tension in the released and tensioned hand levers. In the figure, numerals 1 and 2 are arms, 3 is a central joint, 4,
5 is the joint head, 6 is the tension lever, 7 is the shaft bolt,
8 is the case, 9 is the notch, 10 is the ball, 11 is the notch,
12 is a ball, 13 is a pressure bolt, 14 is an inner part of the push rod, 15 is an outer part of the push rod, 16 is a pressure spring, 17
is a ball socket, 18 is a ball case, 20 is a ball retainer bolt, 21 is a threaded bolt, 22 is an arm tube, 24,
25 is a disk, 26 is a front surface, 27 is a notch, 28 is a ring-shaped shoulder, 29 is a center hole, 30 is a tightening screw, 3
1 is a tightening jaw, 35, 36 are tightening screws, 37,
38 is a tightening jaw, 39 is an opening, 40 is a spring case, 41 is a compression spring, 46 is a case, 54 is a lock nut, 55 is a base plate, and 56 is a give key.

Claims (1)

[Scope of Claims] 1. The axial bolt has at least two arms transversely, swingably connected to each other by a fixable central joint, and supporting ball joints at their ends; is lockable with the central joint by means of a tensioning mechanism and a locking mechanism, the locking mechanism having a push rod acting on the ball joint and disposed in an arm, the push rods being engaged with each other. movable by a relative movement of two inclined abutment surfaces, said abutment surfaces being arranged inside two cavities, said cavities having grooves with a spherical cross section. a ball formed in the shape of and acting on the push rod is mounted, at least one of said cavities is arranged in a case movable in the axial direction on the axial bolt, and the other cavity is arranged on the axial bolt. A joint stand characterized in that it is arranged directly or in a case that can be fixed to the shaft bolt. 2. A joint according to claim 1, characterized in that the axial bolt or the fixable case is held in one arm and the movable case in the other arm for twisting but axial movement. stand. 3. The fixable case, which is provided at the end of the shaft bolt remote from the tensioning mechanism or at the end thereof, has a cross section different from a circular one and does not rotate but is movable in the axial direction into the horizontal hole of the shaft tube. and the movable case, on its side remote from the tensioning mechanism, likewise has a cross-section different from circular and engages in a non-rotatable but axially movable transverse hole of the other shaft tube. The joint stand according to claim 2, characterized in that: 4. A clamping screw with a clamping jaw is arranged in at least one arm, acting on the axle bolt or on the lockable case, with which the relative position of the axle bolt can be blocked. A joint stand according to claim 1, characterized in that: 5. Claim 5, characterized in that one arm has a clamping screw with a clamping jaw acting on the movable case, by means of which the relevant position of the clamping case can be cut off. 1
Fitting stand described in section. 6. The joint stand according to claim 1, wherein the push rod is formed into two parts, and a push spring is inserted into each separated position. 7. The central joint includes two disks through which the shaft bolt passes, each disk having a groove on its outer surface for a slack position of the shaft tube. Fitting stand described in section. 8. At least one of the arms is provided with a lockable joint head on both sides, and the axle bolt and the case have abutment surfaces at diametrically opposed positions. fitting stand. 9. The pushing piece or push rod end adjacent to the ball is formed in a circular shape, preferably in a hollow circular shape, so that a rolling movement of the ball occurs when the part provided at the abutment part moves. A joint stand according to claim 1, characterized in that: 10. The center angle of the ball and the inclination angle of the wedge-shaped curved surface are selected such that the ball rolls at least along a substantially parallel line on at least substantially diametrically opposing points. Fitting stand described in section. 11. The joint stand according to claim 1, wherein the central joint includes a single disc through which the shaft bolt passes, and an arm end connected to the central joint is adjacent to a side surface of the disc. . 12. The joint stand according to claim 11, wherein the arm end is formed as a square tube. 13. A joint stand according to claim 1, characterized in that a compression spring is disposed within the central joint to maintain a locking force of the tensioning mechanism that can be adjusted to open. 14. The joint stand according to claim 13, wherein the compression spring is disposed between the movable case and the tension mechanism. 15. The stand according to claim 13, wherein an end of the compression spring remote from the movable case is supported by a shaft fixed stopper. 16 the compression spring is installed within the case;
Claim 13, characterized in that the case is screwed with a threaded socket that defines the tension.
Fitting stand described in section. 17. Claim 14, characterized in that the end of the shaft bolt remote from the tensioning mechanism is screwed into a fixable case, and the tension of the spring is determined by the screwed-in position. Fitting stand described in section. 18. The joint stand according to claim 17, wherein a lock nut is provided at the end of the shaft bolt that is supported by the fixable case. 19. The stand according to claim 1, wherein the surfaces formed as curved surfaces or inclined surfaces are formed with different inclinations. 20. A joint stand according to claim 13, characterized in that a base plate adjacent to the tensioning lever of the tensioning mechanism is mounted non-rotatably but movably in the axial direction on the shaft bolt. 21. The joint stand according to claim 20, wherein the base plate has a give key, and the give key is inserted into a groove in the longitudinal direction of the shaft bolt. 22. The axial bolt has at least two arms transversely pivotally connected by a securable central joint and supporting ball joints at their ends;
The arm is lockable with the central joint by a tensioning mechanism and a locking mechanism, the locking mechanism acting on the ball joint and having a push rod disposed within the arm, the locking mechanism acting on the ball joint and having a push rod disposed within the arm; is capable of moving a part with two inclined abutment surfaces by relative movement with respect to each other, said abutment surfaces being arranged inside two cavities, said cavities having a spherical cross section. A ball formed in the form of a groove and acting on the push rod is attached, and has a compression spring acting on both parts with said abutment surfaces, the tension of said compression spring being predetermined when the tensioning mechanism is released. A joint stand characterized in that it is adjustable to maintain a predetermined locking force.