DE10234271B4 - holding arm - Google Patents

Abstract

arm, comprising at least two successively arranged and with ball joints (2) articulated arm segments (1), each of which Ball joints (2) has a ball element (9) and this means a fluidic clamping device acting on the ball element (9) can be locked in any position, wherein the clamping device a hydraulic clamping device with at least one hydraulic Connecting line (15), wherein the clamping devices and the Connecting lines (15) are stiff and a closed volume form in which a compression-resistant fluid is filled, as well as additional Means (3) for a reduction of the volume and to a tensioning of the clamping device are provided, with the additional Means (3) comprises a sealing feed screw, which in the Volume protruding into this screwed and herausschraubbar is positioned at the distal end of the support arm.

Description

The The invention relates to a support arm comprising at least two consecutive arranged and hinged together with ball joints Arm segments and a holding device according to claim 9.

holders serve the fixation of instruments during an intervention and include at least a holding arm. Unlike active manipulators, these are Holding devices passive holding systems in the sense of tripods, which, once set while of the procedure generally no longer be changed. The holding device is during positioned at the appropriate location and has this one Stand or one other attachment device. On the other side of the support arm a suitable holder for fixing the instrument is provided. For one variable orientation of the instrument is the arm with joints fitted. For a reliable one Fixation need These joints are designed to be stiffenable, with a principle low number of joints and a high clamping effect the stability of the fixation decisively influence.

Basically different one holding devices whose joints are characterized by a non-adjustable Resistor clutch, such as by a slip clutch, on the one hand or stiffen by adjustable clamp on the other hand to let.

One special field of application for Holding devices and retaining arms of the type mentioned provides the surgery. Here the task is a surgical Instrument such as an endoscope at a predetermined position and orientation wobble free for to hold any time.

For this offer multi-joint holding systems with clamping devices for Joint lock on. However, most known systems have mechanical activatable clamping devices in which the joints individually can be locked by screws, pins or lever mechanisms. such However, fixings have the disadvantage that, depending on the design Locking a more or less large locking movement occurs. This is precise Adjustments, as in medical technology, but also in measurement tasks generally occurring, problematic and undesirable and requires in the Usually time-consuming readjustments of the instrument.

energetically operated clamping devices, such. B. fluidic, electromagnetic or piezoactuator systems, with appropriate design do not need these disadvantages but for that a separate power supply, i. additional aggregates. urges one for one a use of a holding device high reliability on the one hand and a small size and thus good handling on the other hand, is a mechanical and electrical decoupling of Holding system of all supply units practically inevitable. As a result, the required additional aggregates are separate Systems usually with their own energy needs (in general Network connection).

In the DE 295 11 900 U1 discloses a manually adjustable holding device for endoscopes and retractors. It has a holding arm with a plurality of successively arranged arm segments, which are connected to each other with ball joints articulated. The ball joints are locked by a pneumatic tensioning device, the required compressed air supply via an external control unit is ensured and activated by a separate hand switch on the handle.

Furthermore, in the DE 691 06 701 T2 describe a holding arm with also with hydraulically lockable ball joints, wherein the hydraulic pressure via conventional, ie external supply means is introduced into the holding arm.

outgoing It is the object of the invention to provide a holding arm a fluidic clamping device and equipped with this holding device to propose which or which manages without an external control unit.

The The object of the invention is achieved by a holding arm according to the first Patent claim and with a holding device using of the support arm according to the ninth Patent claim solved. Preferred embodiments the article according to claim 1 are the subject of claims 2 to 8 indicated.

The object is achieved by a support arm, comprising at least two successively arranged and articulated ball joints with each other connected arm segments, each of the ball joints having a ball member and these are locked by means of acting on the ball member fluidic clamping device in any position solved. An essential feature here relates to the clamping device, which is designed as a hydraulic clamping device with at least one hydraulic connecting line, wherein the clamping devices and the connecting lines are stiff and form a closed rigid volume. The volume is completely filled with a compression-stiff fluid. Further, means for a change, ie, a reduction or increase in the volume provided, whereby the fluid, a fluid pressure can be impressed, which causes increasing pressure, a tightening of the clamping device and this pressure picks up with decreasing pressure again.

Preferably contains the hydraulic clamping device at least one piston, which acts on the ball element and this presses against a ball guide. (Claim 2) Canting or eccentric force transmission is avoided according to claim 3 characterized in that the piston has an axis symmetry around an axis of symmetry and along this in one guideway moves, with the axis of symmetry through the center of the Ball element runs. The attack surface the piston on the ball element also has as a result of these conditions a symmetry to the axis of symmetry, a necessary condition So for an eccentric force on the ball element. The ball guide points also an axis symmetry about the axis of symmetry, (claim 4) which also passes through the center of the ball element.

The Retaining arms exist in addition to other components depending on the embodiment from one or more arm segments. Preferably in these Arm segments integrated hydraulic connection lines. Point the arm segments according to claim 5 cavities, which towards the outside are closed, can this as an integrated instead of the separate hydraulic connection lines be designed and serve.

It lends itself, a means for a reduction of the volume and for a tension of the clamping device so that all ball joints of the support arm clamped simultaneously and solved again become. This allows the support arm in a particularly advantageous manner be set with all its degrees of freedom and in a chosen position only by operation be locked a means. Specifically, this means that the hydraulic clamping devices all to one connecting cable be connected and with this a closed volume form. Since the ball joints and the arm segments arranged one behind the other need to have bypass lines be provided, which the hydraulic connection lines in connect two adjacent arm segments hydraulically while bridging the ball joints.

alternative can single or a group of clamping devices equipped with independent means become. This is useful when holding a tool while egg nes Be corrected in its position within certain limits or the position of the support arm first in a first step is roughly set and then in a second step with elevated precision fine to adjust.

The Invention will be described with reference to the following embodiments with the aid of following figures explained. Show it

1 an embodiment of the holding device with holding arm in a side view,

2 a sectional view of an embodiment of a ball joint with hydraulic clamping device, as well

3a to c three possible arrangements of a feed screw for manual activation of the joint lock.

A holding arm of the type described above comprises, as in 1 represented by an embodiment, at least two arm segments 1 with hydraulically lockable ball joints 2 and a feed screw 3 with sealed thread. The feed screw 3 serves as the aforesaid means for reducing the volume of the connecting line for the clamping devices for the locking of the ball joints 2 , where all clamping devices are connected to the connecting cable.

The support arm is on one side, namely the proximal side with a bearing block 4 to a stand rod 5 mounted, which in turn with a screw terminal 6 on a rail 7 , For example, arranged laterally on an operating table, placed and manually fixable. Here is the tripod rod 5 in the screw terminal 6 axially displaceable, pivotable and rotatable. The bearing block 4 is on the tripod pole 4 rotatable and axially displaceable. bearing block 4 and screw terminal 6 are each with a clamping device, preferably a clamping screw 8th , equipped on the stand rod 5 manually lockable.

On the other, the distal side with an in 1 schematically illustrated instrument holder 19 connected. It is used to hold tools 20 all kinds, in particular medical tools and instruments, but also cameras, endoscopes, light sources or sensors.

Of the Holding arm with the said distal and proximal adjoining components together form a holding device.

Not in 1 shown is a partial or complete sterile packaging for the holding device, which is necessary for reasons of sterility during a surgical procedure, especially when the support arm is not thermally sterilized. Even if the fluid for the hydraulic clamping devices of the ball joints has sufficient temperature resistance for a sterilization effort, it is recommended that at least the ball joints be packed in a sterile manner and thus prevent possible leakage. Basically, all fluids which are suitable for compression are suitable, but preferably hydraulic fluids, pastes or greases.

2 shows a ball joint with clamping device in a sectional view. It consists essentially of a ball element 9 which in a housing 10 in a ball guide 11 is guided. The housing 10 as well as the ball element 9 form constructively with one arm segment each 1 one unity.

The clamping device comprises a piston 12 , which in the housing concentric to an axis of symmetry 13 arranged and displaceable by a compression spring 14 against the ball element 9 and together with this against the ball guide 11 is biased. In particular, a plurality of stacked disc springs are suitable as a compression spring.

The connection cable 15 is due to a hollow volume in the arm segments 1 formed, for a fluidic bridging of the ball joints on the one hand, these are continued in the spherical segments and on the other hand, the pressure cylinder 12 designed as a ring cylinder. Of crucial importance is that the volume in the connecting line must not change during an adjustment of a ball joint. seals 16 prevent or hinder leaks on the piston 12 ,

The sealing feed screw 3 accesses the connection cable 15 by screwing in, taking the volume of the connecting cable 15 is changed and the clamping devices are strained or loosened. It does not matter at which point the volume is changed. In this respect, a positioning of the feed screw takes place 3 on the holding arm according to handling criteria. 3a and c show by way of example two possible arrangements of the feed screw 3 each on the housing 10 (see also 1 ), while 3b an arrangement in the region of a Haltearmsegmentes 1 shows.

The feed screw 3 has in the embodiment shown, as in 3a to c shown, optionally a pressure damping in the form of a small pressure pin 17 which increases with increasing fluid pressure against a spring 18 is pressed into the feed screw. As a spring, for example, is a rubber block. Instead of the pressure damping is also similar constructed an overpressure protection can be used, wherein the spring element is exchanged for a component which yields reversibly or irreversibly at a certain pressure. However, it should be noted that no loose particles or fragments get into the fluid.

1

Haltearmsegment

2

ball joint

3

feed screw

4

bearing block

5

Support rod

6

screw

7

rail

8th

clamping screw

9

ball element

10

casing

11

ball guide

12

piston

13

axis of symmetry

14

compression spring

15

connecting cable

16

poetry

17

pushpin

18

feather

19

instrument holder

20

Tool

Claims (8)

Holding arm, comprising at least two successively arranged and with ball joints ( 2 ) articulated arm segments ( 1 ), wherein each of the ball joints ( 2 ) a ball element ( 9 ) and by means of a on the ball element ( 9 ) acting fluidic clamping device can be locked in any position, wherein the clamping device is a hydraulic clamping device with at least one hydraulic connecting line ( 15 ), wherein the clamping devices and the connection lines ( 15 ) are stiff and form a closed volume in which a compression-resistant fluid is filled, and in addition means ( 3 ) are provided for a reduction of the volume and for a clamping of the clamping device, wherein the additional means ( 3 ) comprises a sealing feed screw, which in the volume projecting into this screwed and herausschraubbar and is positioned at the distal end of the support arm. Holding arm according to claim 1, characterized in that the hydraulic clamping device at least one piston ( 12 ), which refers to the Ku gel element ( 9 ) and this against a ball guide ( 11 ) expresses. Holding arm according to claim 2, characterized in that the piston ( 12 ) an axis symmetry about an axis of symmetry ( 13 ), the piston ( 12 ) along the axis of symmetry ( 13 ) is mounted laterally movable and the axis of symmetry ( 13 ) through the center of the ball element ( 9 ) ver runs. Holding arm according to claim 2 or 3, characterized in that the ball guide ( 11 ) an axis symmetry about the axis of symmetry ( 13 ) having. Holding arm according to one of claims 1 to 4, characterized in that the arm segments ( 1 ) Cavities as integrated hydraulic connecting lines ( 15 ) exhibit. Holding arm according to one of claims 1 to 5, characterized in that the ball joints ( 2 ) and the clamping devices have hydraulic bridging lines which connect the hydraulic connecting lines ( 15 ) in two adjacent arm segments ( 1 ) connect to each other hydraulically. Retaining arm according to one of claims 2 to 6, characterized in that the ball joints ( 2 ) and the piston ( 12 ) of the clamping device have cavities as an integrated hydraulic bypass line. Holding device for a medical instrument, comprising at least one holding arm according to one of the preceding Claims.