ES2359463T3 - BLOCKABLE ARTICULATION. - Google Patents

Abstract

Lockable joint, especially lockable ball joint, comprising (a) a first arm (14) having a rotating head (30), (b) a bushing (32), the rotating head (30) being pivotally mounted in the bushing (32), and (c) a locking device (90) arranged to lock the rotating head (30) with respect to the bushing (32), the locking device (90) having a piston (70) '), (ii) a source (64) of pressurized gas, and (iii) a drive device (92) arranged to reversibly disconnect the piston (70') from the source (64) of pressurized gas, characterized in that (d) the source of pressurized gas is a gas cartridge (64).

Description

Field of the Invention

The invention relates, in general, to the field of surgical instrumentation. More particularly, the invention relates to a lockable joint, especially a lockable ball joint, comprising a first arm, the first arm having a rotating head, a bushing, the rotating head being pivotally mounted on the bushing, a blocking device arranged to block the rotating head with respect to the bushing, the blocking device having a piston, a source of pressurized gas, and an actuating device arranged to reversibly disconnect the piston from the source of pressurized gas . The invention also relates to the field of related structures that are fixed to a surgical table or other fixed structure.

Such lockable joints are known from US 5,201,325, US 6,632,170, US 5,201,325 and EP 1 520 548 A2. The lockable seals in these documents can be operated by pressurized air supplied through a gas hose. Because the gas pressure of the pressurized gas in the gas hoses is usually not sufficient to securely lock the gasket, a pressure boosting system is provided. Another lockable joint is known from US 5,271,384. This lockable joint experiences a clamping force that is not enough for many applications.

The problem of the present invention is to enhance the reliability and clamping force of the joint.

The invention solves the problem with a lockable joint, especially a lockable ball joint, comprising a first arm, the first arm having a rotating head, a bushing, the rotating head being pivotally mounted on the bushing, a device of blocking arranged to block a rotating head with respect to the bushing, the locking device having a piston, a source of pressurized gas, and an actuating device arranged to reversibly disconnect the piston from the source of pressurized gas, in the one that the source of gas under pressure is a gas cartridge.

According to another aspect, the invention solves the problem with a lockable joint, especially a lockable ball joint 25, comprising (a) a first arm, the first arm having a rotating head, (b) a bushing, being mounted so pivoting the rotating head in the bushing, and (c) a locking device arranged to lock the rotating head with respect to the bushing, the locking device (i) having a piston, (ii) a gas cartridge retaining element arranged for separately accommodating a gas cartridge, and (iii) an actuating device arranged to reversibly disconnect the gas cartridge piston or 30 from the gas cartridge retainer.

According to a more additional aspect, the invention solves the problem with a method for fixing a lockable joint according to claim 27.

Background of the invention

Typically, surgical retractors were hand instruments with multiple curved fingers used to keep the incisions open during surgical procedures. The surgeon or an assistant hooked the fingers of the surgical retractor over the edge of an incision and applied tension to keep the incision open to provide the surgeon with access to internal body structures.

In approximately the past two decades, surgical retractors have been developed that are attached to a surgical table or other structure to allow retraction without the need for the surgeon or an assistant 40 to constantly hold the retractor.

For the surgical retractor system according to the invention, a table rail post can be the basis of a surgical retractor system. It provides an anchor for a frame or other physical support to which retractable instruments and other surgical instruments can be attached. A variety of retractor instruments with variably shaped retractor fingers are used in surgery to help the surgeon keep an open surgical incision or to separate anatomical structures. Surgical retractor systems may use cam mechanisms or, occasionally, bolted fasteners to lock various elements of the retractor system into position.

The surgical retractor system according to the invention can be a round stem retractor system and / or a flat stem retractor system. Flat rod retractor systems experience the limitation that, due to the rectilinear nature of the various components, the components must be joined at substantially right angles to interconnect. Therefore, the number of orientations in which flat rod retractor systems can be assembled is limited.

Round stem retractor systems are generally preferred because they allow the interconnection of the various components of the retractor system at a variety of different angles due to the ability of the 55 round stem parts of the system to rotate relative to each other and hold components .

Round rod retractor systems include several rod-shaped parts that are initially connected to each other by threaded screw-type fasteners. When threaded screw type fasteners are used, there may be a tendency for screw fasteners to deform the cylindrical elements of the retractor system. In addition, the assembly, positioning and interconnection of the parts of the retractor system may require both hands, or possibly both hands of a person, plus an assistant to assemble the system. 5 Therefore, eccentric locking or cam locking connection systems are preferred for mounting the surgical retractor on the first arm and / or for fixing the anchoring element to the third arm.

The cam locking system may include two interconnected fasteners that are configured to grip the elements of the bar-shaped retractor system and that can be rotatably adjusted relative to each other. A rod-shaped component is seized in each clamp. The two interconnected fasteners are activated by some type of actuator such as a lever that then locks the two fasteners to two rod-shaped elements and also simultaneously locks the two fasteners relative to each other in rotation. A disadvantage of this arrangement is that when the fasteners are released, they are completely released from both rod-shaped elements as well as in relative rotation, which requires that the retractor system be fully repositioned and re-aligned before a new one subjection. fifteen

Surgical retractor systems are used to manipulate living tissue. The application of pressure to living tissue can damage the cell structure or reduce blood flow to the tissue. Live tissue may be damaged by applying pressure for too long. Therefore, it is recommended that during surgical procedures in which mechanical retractors are used, periodically the retractors are loosened or the tension in the retractors is decreased to allow greater blood flow to the tissue that is being retracted to avoid hypoxia of tissue and possible necrosis. This requirement, together with the limitation of current retractor systems, creates a dilemma for the surgical team. Surgical teams can disconnect the surgical retraction system periodically, but then they will have to make complete adjustments of each surgical retractor to reconnect it. Alternatively, the surgical team may leave the living tissue retracted under tension for long periods of time and risk damaging the tissue or a necrosis in the tissues that are being retracted. Surgical team members tend to be reluctant to disconnect and then readjust the retractor system if readjustment takes time or is difficult or if readjustment alters the carefully arranged relationship of anatomical structures.

Another issue that arises with the current round-rod surgical retractor systems stems from the fact that surgeons generally prefer to locate the retractors so that they provide an angled retraction tension 30. Surgeons prefer this approach to move the retractor to the side of the field in which they should work, so that the retractor does not interfere with their movements. When surgical retractors are displaced, it is very often impossible to position the retractors so that the retractor pulls completely linearly in relation to the longitudinal axis of the rod-shaped elements. This confers a torsional or rotational force to the fasteners that are fixed to the cylindrical or rod-shaped elements of the retraction system 35. This force tends to cause the fastenings of the retraction system to slide on the bars in a rotating manner. A common answer to this problem is to tighten more and more the grip that is applied to the bar-shaped element. Unfortunately, when pressed beyond a certain point, the fastener will tend to create a deformation or wear of the rod-shaped element to which it is attached making it more difficult to adjust the system for future use. 40

A problem that arises with the currently available retraction systems is that when a retractor is fixed to the system by means of a current clamp, the multi-axis joint created between the components is completely locked so that the joined components are immobilely fixed on all axes. . Usually, it is necessary for the surgeon or an assistant to increase or readjust retractions for certain activities. Adjusting retractions means that the surgeon or an assistant should loosen the support that holds the retractor, relocate the retractor, and then reapply the restraint. Since the support of the prior art is completely released from two bars and in rotation simultaneously, at least two hands are required to realign and re-tension the system. This can be very impractical since there is a period of time in which the tension in the retractor is reduced and the tissues can move in an unwanted way when the tension is reduced.

Retractor racks generally include a first frame arm, a second frame arm and a locking device that can also be called a fastener and that holds the left frame arm and the right frame arm in a fixed position, from so that a surgical retractor can be attached to the left and right frame arms. In addition, retractor frames generally include a third support arm that can be attached to a surgical table rail post. Existing retractor racks experience a number of limitations. For example, the fastener that holds the right and left frame arms 55 generally locks the right and left frame arms in position simultaneously. While a convenient locking of the frame arms takes place simultaneously, it may be difficult to adjust the right and left frame arms independently of each other. In addition, in many retractor frames of the prior art the clamping element also holds the pivoting connection between the support arm and the clamping element at the same time that the left and right frame arms 60 are held, sometimes making adjustment difficult of the retractor frame as desired.

Summary of the invention

For the purpose of the following description, a blocking device may be any device that is

arranged and adapted to immobilize the rotating head with respect to the bushing. It is possible to provide two or even more locking devices. The locking device can provide a friction lock with the rotating head. Alternatively, the blocking device can be adapted for a positive block or for a combination of both positive and friction block.

The drive device can be any device that is adapted and arranged to allow interrupting a gas communication between the gas cartridge and the piston. For example, the actuator may be a valve.

A gas cartridge may be a cartridge containing a chemical composition or a mixture of chemical compositions that is / are gaseous at room temperature of 20 ° C and ambient air pressure of 1013 hPa. Alternatively, the gas cartridge contains a chemical composition that can be contacted with another chemical composition to react chemically so as to produce such a gas.

An advantage of the present invention is that it is not necessary to provide an external source of pressurized air. Such an external source of pressurized air may not be available. Especially in hospitals, pressurized air systems are often contaminated with bacteria, so this air should not be used for operating devices. As an additional advantage, air hoses are no longer needed. Air hoses carry the risk of explosion and have to be checked regularly. They are also uncomfortable to use and carry the risk of staff stumbling. Another advantage is that the gas cartridge can be a disposable gas cartridge. Disposable gas cartridges are easy to handle and store, so that the lockable seal has high reliability and availability. Another advantage is that the lockable joint can be easily operated. A lockable joint is therefore advantageous for high precision applications. twenty

In a preferred embodiment, the gas cartridge has an internal pressure of more than 4 MPa or 40 bar. In particular, the internal pressure is more than 5 MPa or 50 bar. This high pressure makes it possible to operate the locking device directly by the piston. Conventional air pressure systems used for example in hospitals usually have a pressure below 0.7 MPa, so that the force of the piston has to be increased by a suitable device. These devices are susceptible to errors and are expensive. The use of a gas cartridge having an internal pressure of more than 4 PMa thus leads to a lockable gasket that is easy to manufacture, cheap and resistant.

In a preferred embodiment, the gas cartridge contains less than 1000 g of gas. In particular, the gas cartridge contains less than 100 g of gas, for example from 12 g to 50 g of gas. These types of gas cartridges are small and easy to handle, but contain a sufficient amount of gas for most applications of the lockable gasket.

It is preferred that the gas cartridge contains carbon dioxide, pressurized air, nitrogen under pressure, nitrous oxide under pressure, noble gas under pressure, oxygen under pressure, or a mixture of two, three, four or five of the aforementioned substances . In particular, it is preferred that the gas cartridge contains carbon dioxide and therefore can be referred to as a carbon dioxide cartridge. Carbon dioxide is not toxic, it is easy to manufacture and it is not harmful when handled. An advantage is the fact that carbon dioxide is a liquid at room temperature of 20 ° C, if the pressure is above 5.8 MPa. As a liquid, carbon dioxide has a high density so that even a small carbon dioxide cartridge can store a significant amount of carbon dioxide.

It is preferred that the carbon dioxide cartridge contains sterile carbon dioxide. The used carbon dioxide 40 from a sterile carbon dioxide cartridge can be released into the ambient air even in an operating room.

It is preferred that the lockable joint has a main body, the main body comprising the bushing in the locking device, the locking device having a fixing element that is housed in the main body, and the piston being arranged to press the element of fixing against the rotating head. It is particularly advantageous that the piston and the fixing element are connected, so that moving the piston in a working direction of the piston leads to the movement of the fixing element in a fixing working direction, whereby the working direction of the piston is parallel to the working direction of the fixing element. This produces a particularly advantageous flow of force.

It is a particular advantage if the piston and the fixing element are directly coupled, so that moving the piston by predetermined pistons leads to a movement of the fixing element along the same predetermined distance. That is, no force increase mechanism is required. This leads to a lockable joint that is easy to manufacture. In particular, the piston is arranged to press against the rotating head. The part that is in contact can be called the fixing section.

In a preferred embodiment, the main body comprises a cylinder, the cylinder having an inlet opening, the piston being mobilely housed in the cylinder and comprising a fixing section for pressing against the rotating head, the fixing section being located in the opposite side of the entrance opening. In this embodiment, the gas flowing through the inlet opening into the cylinder pushes the piston towards the rotating head thereby pressing its fixing section against it. The bushing is arranged so that the rotating head presses against the bushing when the fixing section presses against the rotating head. 60

Therefore, the rotating head is locked between the bushing and the fixing section. Since the piston is housed tightly in the cylinder and since the bushing is rigidly mounted on the main body, the rotating head is locked, that is, fixed and fastened tightly, to the main body. If a high gas pressure is provided, for example 6 MPa, a clamping force of more than 4000 N. is easily achieved.

In a preferred embodiment, the main body comprises a gas cartridge retainer to replace the gas cartridge in a replaceable manner. Then it is possible to use disposable or non-returnable gas cartridges that are available at low prices. In addition, it is possible to use the lockable joint in places where a pressurized air system is not available. Examples are developing countries or remote locations.

It is preferred that the fixing element, in particular the fixing section of a piston, is arranged to come into contact with the rotating head in a contact area of the fixing element which is ring-shaped and has a ring width less than 1 mm This produces a particularly strong clamping force that the locking device exerts on the rotating head, since a small ring width leads to a high pressure which in turn causes an elastic deformation of the rotating head.

In a preferred embodiment, the fixing element is arranged for a friction block between the fixing element and the rotating head. This leads to a lockable joint that is easy to manufacture and resistant.

The area of the contact section may be segmented. To achieve this, the fixing element, for example the piston fixing section, can be provided with spaces or cuts. These spaces may also be arranged to allow cleaning of the lockable joint, in particular the rotating head, after use or to disinfect the lockable joint. twenty

It is preferred that the rotating head has an outer diameter of the rotating head and that it comes into contact with the fixing element, for example the piston fixing section, in a contact area of the ring-shaped rotating head that is larger than 0.94 times the outer diameter of the rotating head.

It is preferred that the first arm has a longitudinal axis of the arm and that the outer diameter of the contact area and the longitudinal axis of the arm form a substantially constant effective angle of less than 20 °. In particular, it is preferred that the effective angle be greater than 1 °.

To allow many lock and release cycles, it is preferred that the gas cartridge has an outlet opening of the gas cartridge, the cylinder and a gas cartridge being in gas communication through a gas conduit between the outlet opening of the gas cartridge and the inlet opening of the cylinder, the gas conduit having a volume of less than 1000 mm3, in particular less than 500 mm3. To maximize the number of lock and release cycles, it is also preferred that the piston has a stroke of less than 2 mm, in particular less than 1 mm.

To provide a strong clamping force, the piston preferably has a piston diameter of more than 20 mm.

According to another aspect, the invention relates to a lockable joint assembly comprising (a) a lockable joint 35 according to the first aspect of the invention, (b) a second arm having a second rotating head, (c) a second sleeve , the head being pivotally mounted on the second bushing, (d) a second locking device arranged to lock the second rotating head with respect to the second bushing, the second locking device (i) having a second piston connected in a disconnectable manner to the gas cartridge and (ii) a second drive device arranged to reversibly disconnect the second piston from the gas cartridge. For easy handling, the second arm is preferably arranged on the side opposite the first arm.

To secure the lockable joint to an anchoring element, the lockable joint preferably comprises (a) a support arm having a rotating support head, (b) a support arm bushing, pivotally mounted on the arm bushing of support, and (c) a support arm locking device arranged to lock the rotating head of the support arm with respect to the support arm bushing, the support arm locking device (i) having a piston of the support arm connected with possibility of interruption to the gas cartridge and (ii) a support arm drive device arranged to reversibly disconnect the piston from the support arm of the gas cartridge.

According to a further aspect, the invention relates to a surgical retractor system, comprising (a) a lockable joint assembly according to the invention, (b) an anchoring element adapted to be mounted on an operating table, being mounted releasingly the anchoring element in the support arm, the first arm being adapted to act as a frame element to accommodate at least one surgical retractor.

The surgical retractor frame of the present invention is adapted to be anchored in a surgical post attached to a surgical table rail, or to another fixed structure, to allow the application of surgical retractors that are used for the retraction of anatomical structures.

The surgical retractor frame of the present invention may include a main body in the form of a control handpiece, a support arm and two frame arms, ie the first arm and the second arm.

The support arm and the two frame arms (first arm and second arm) can be articulated with the control handpiece through ball joints. Each ball joint supports one of the support arms and the two frame arms. Each ball joint can be locked and released independently at any location within its articulation range. That is, each ball joint can be released, adjusted and held independently, independently of the other two ball joints. 5

The independent gas pressure driven locking mechanism of the present invention is operated by a pressurized gas source in the form of a gas cartridge, for example a small pressure gas cylinder containing pressurized gas such as carbon dioxide. carbon, nitrogen, or compressed air.

In an exemplary embodiment, the supply of pressurized gas is provided in a small carbon dioxide cartridge or cylinder. The carbon dioxide cartridge is contained within the control handpiece 10 of the present invention. The carbon dioxide cylinder is intended to be replaced with each use of the surgical retractor frame. For example, the control handpiece may have a generally cylindrical chamber in which the compressed gas cylinder can be located. Once the gas cylinder is located in the chamber, a screw can be inserted to card the gas cylinder behind the gas cylinder and can be tightened until the gas cylinder is pierced by a trocar or a hollow needle. The gas cylinder is simultaneously sealed to the control manual part 15.

The main body or control handpiece may further include an independent push button or other valve actuator to operate each individual ball joint. The support arm locking device operates the ball joint for the support arm.

In one aspect of the invention, the operation of the support arm locking device is such that the support arm 20 is blocked because the pressurized gas presses the piston of the support arm against the rotating head, ie a spherical element, of the ball joint except when the drive device is pressed, for example a push button. The support arm locking device is structured so that when its button is pressed, the pressurized gas acting against the piston of the support arm is released while the pressurized gas is sealed inside the gas cartridge so that the gas is not constantly ventilated. The drive device for the first arm operates the first arm, that is the right frame arm, and the second locking device operates the second arm, that is the left frame arm. The spherical seals are arranged so that a certain tension is maintained on the spherical element by the piston, even when the gas pressure is released. This provides tension so that the frame arm can be adjusted in a desired position without "falling" as a result of gravity. 30

In one aspect of the invention, the pressurized gas cylinder has a fail-safe pressure release so that if a hospital staff member mistakenly places the surgical retractor frame in an autoclave for sterilization with the Gas cylinder still installed, the gas cylinder will be ventilated safely, thus avoiding the risk of an explosion in the autoclave.

In one aspect of the invention, the pistons that are supported with their fixing sections against the spherical joint spheres 35 have a piston seal that includes a stainless steel spring within the piston seal. O-rings or pistons without seals can also be used.

The compressed gas used to operate the pistons in the surgical retractor frame can be supplied at a pressure of between approximately 200 and 350 pounds per square inch. In one aspect of the invention, the system operates at pressures of approximately 300 pounds per square inch. 40

It is noteworthy that the displacement of the piston in the surgical retractor frame can be very short; of the order of less than a millimeter. The adjustment of the piston inside the cylinder is quite tight so that the piston maintains tension on the sphere of the ball joint even when the pressure on the piston is released. The piston and the ball joint sphere can be made of a metallic material such as, for example, Nitronic 60, Galltough ™, or V4A ™ steel. Four. Five

The blocking devices may comprise dual-function push-button valves that ventilate the pressure from the respective piston and cylinder and seal the gas passages or conduits from the pressurized gas source simultaneously.

The control handpiece may include an ergonomic handle. The body of the control handpiece can be formed, for example, by stainless steel such as 400 series stainless steel or V4A steel. fifty

In one embodiment of the invention, the first and second frame arms, for example the left and right, and the support arm may be tubular structures instead of the more conventional solid bars. This lightens the structure of the surgical retractor frame without significantly sacrificing resistance. The spherical joint spheres can be solid or hollow. All metal parts of the present invention can also be formed from materials such as titanium or stainless steel. 55

The gas cartridge can be supplied in a sterile or non-sterile state. When non-sterile cartridges are used, a sterile sleeve can be used to maintain a sterile field in the operating room to allow a cartridge exchange, if necessary, during a surgical procedure.

Preferred embodiments are described below with respect to the drawing, in which

Figure 1 is a perspective view of an exemplary embodiment of a surgical retractor system according to the present invention;

Figure 2 is a perspective view of an exemplary embodiment of a lockable joint assembly according to the present invention; 5

Figure 3a is a side cross-sectional view along plane A of the embodiment shown in Figure 2 in a locked position;

Figure 3b is a schematic cross-sectional view of a detail of Figure 3a;

Figure 3c is a view according to Figure 3a representing a release position;

Figure 4a is a first front cross-sectional view of an alternative embodiment of a lockable joint assembly 10 according to the present invention;

Figure 4b is a second front cross-sectional view of the embodiment of Figure 4a;

Figure 5a is a perspective view of the piston comprising the fixing element;

Figure 5b is a side cross-sectional view of the piston of Figure 5a;

Figure 5c is a front view of the piston shown in Figures 5a and 5b; fifteen

Figure 6a is a bushing for a lockable joint according to the invention in a perspective view;

Figure 6b is a cross-sectional view of the bushing of Figure 6a;

Figure 6c is a side view of the bushing of Figures 6a and 6b;

Figure 6d is a section along C-C of Figure 6c;

Figure 7 is a perspective view of a support arm and two frame arms of a surgical retractor frame 20 according to the invention;

Figure 8 is a cross-sectional view of another embodiment of a lockable joint according to the invention; Y

Figure 9 is a cross-sectional view of another embodiment of a lockable joint according to the invention. 25

Figure 1 shows a surgical retractor system 10 comprising four surgical retractors 12.1, 12.2, 12.3 and 12.4. Next, reference numbers without counting the suffix refer to the object as such. The surgical retractors 12 are mechanically fastened either to a first arm 14 or to a second arm 16 of a surgical retractor frame 18.

Surgical retractor frame 18 also comprises an anchoring element 20 that is adapted to be mounted on an operating table (not shown). The anchoring element 20 has a coupling anchor 22 which is connected to a holding bar 24. A joint 26 of the anchoring element is provided for releasably and pivotally mounting a support arm 28 of the surgical retractor frame 18. The first arm 14 and the second arm 16 have the same shape and are cylindrical in sections and form an arc. The support arm 28, the first arm 14, the second arm 16 and a schematically shown main body 34 (described 35 below in greater detail) that join them together, form part of a lockable joint assembly 49 (also described more forward in greater detail).

Figure 2 depicts a lockable joint assembly 49. The first arm 14 has a rotating head 30 that is housed in a bushing 32. The bushing 32 is part of the main body 34 which can also be referred to as a control handpiece. The main body 34 comprises a button 36 of a locking device comprising 40 components that are used to lock or release the first arm 14 with respect to the main body 34 and which will be described in greater detail below. The main body or control handpiece 34 also comprises a gas cartridge retaining element 38 having a gas cartridge chamber screw 40, which is releasably disposed. Figure 2 also depicts a bushing 42 of the support arm that is also part of the main body 34. Four. Five

Figure 3a shows a sectional view of a lockable joint 43 according to the invention. At the same time, Figure 3a represents a cross section of the lockable joint assembly 49 with respect to the plane A of Figure 2. It should be noted that a joint 43 by definition has only one arm and one joint, especially a spherical joint. Devices with more than one arm are called lockable joint assemblies. Preferably, all arms of the lockable joint assembly are mounted on a single rigid main body. Therefore, a lockable joint 43 43 forms part of the lockable joint assembly 49.

In Fig. 3a there is shown a support arm lock device 44 which is adapted to releasably lock a rotating head 46 of the support arm of the support arm 28 with respect to the main body or the control handpiece 34. The support arm lock device 44 comprises a pushbutton 48 of the support arm that projects over the main body 34, so that it can be easily operated with the tip of the finger. Alternatively, the button 48 of the support arm can be completely located in a recess, so that it is protected against an unintended drive.

The support arm lock device 44 also comprises a support arm valve element 50 that has a substantially cylindrical shape and is tightly housed in a bore 52 and gas tightly sealed against it. The valve element 50 of the support arm is mounted on the push button 48 of the support arm and is prestressed in a locked position (shown in Figure 3a) by a spring 54 located on the side opposite to the push button 48 of the support arm support.

In the locked position, an annular recess 56 in the valve member 50 of the support arm provides gas communication from a first gas channel 58 to a second gas channel 60 which both have a diameter of 3 mm. The annular recess 56, the first gas channel 58, and the second gas channel 60 form a gas conduit 61 having a volume V. This volume V must be reasonably small, for example 250 mm3 or less. However, a larger volume V is also possible. The first gas channel 58 can and extends from the perforation 52 to the gas cartridge retaining element 38 and in particular to an outlet opening 62 of the gas cartridge. a cartridge 64 of carbon dioxide. The carbon dioxide cartridge 64 can be disinfected, for example, by exposure to x-rays or γ rays.

Carbon dioxide cartridge 64 contains approximately 12 grams of carbon dioxide at a cartridge pressure of approximately 6 MPa. At room temperature, most of the carbon dioxide is liquid due to high pressure. The carbon dioxide escapes from the carbon dioxide cartridge 64 through the first gas channel 58, the annular recess 56 and the second gas channel 60, and flows through an inlet opening 66 of the cylinder into a cylinder 68. In cylinder 68, a piston 70 of the support arm is housed and sealed in a gas-tight manner through an O-ring 72. Alternatively, a gasket or a washer can be used.

In the locked position shown in Figure 3a, a gas cylinder pressure in the cylinder 68 is equal to the gas cartridge pressure in the carbon dioxide cartridge 64. Therefore, the piston 70 is pressed in a working direction of the piston so that a fixing section 74 of the cylinder 68 acting as a fixing element is pressed against the rotating head 46 of the support arm. In other words, the piston 70 directly presses 30 against the rotating head. In Figure 3a, the working direction of the piston is equal to the working direction of the fixing element. The distance between a locking position of the piston 70 of the support arm and a position in which it is fully retracted, that is, in which it abuts the wall with the inlet opening 66 of the cylinder, is called stroke s. In other words, the stroke s is the maximum displacement of the piston. It is equivalent to 0.5 mm. 35 P

Figure 3b shows a schematic cross-section of the piston 70 of the support arm and a rotating head 46 of the support arm. The fixing element in the form of fixing section 74 comes into contact with the rotating head 46 of the support arm in a contact area 76 of the fixing element. The contact area 76 of the fixing element is ring-shaped and has a ring width w of approximately 0.5 mm. The surfaces of the rotating head 46 of the support arm and the fixing section 74 are polished or ground so that a friction lock is provided. The rotating head 46 of the support arm is a ball or a sphere and has an outer diameter Dsh of the rotating head. The piston 70 of the support arm has a diameter Dpiston, which is 0.94 times the rotating head of the diameter Dsh or greater. The contact area 76 has an outside diameter Dca of the contact area that is 0.94 times the rotating head of the diameter Dsh or greater.

The support arm 28 has a longitudinal L axis. If the longitudinal axis L is aligned with the longitudinal axis of the piston 70 of the support arm, as shown in Figure 3b, an effective angle α is formed between a plane E perpendicular to the longitudinal axis L and the outer diameter Dca of the Contact area.

Figure 3c shows a support arm lock device 44 in its release position with the pushbutton 48 of the support arm pushed down against the deflection force of the spring 54. It can be seen that the annular recess 56 no longer joins the first gas channel 58 with the second gas channel 60, thereby interrupting the cylinder 50 68 with respect to the carbon dioxide cartridge 64. In the release position, a second annular recess 78 connects a first output channel 80 with a second output channel 82 that carries a discharge opening (not shown). Therefore, in the release position, the carbon dioxide escapes through the first outlet channel 80, the second annular recess 78 and the second outlet channel 82 until the gas cylinder pressure in the cylinder 68 is equal to the Ambient ambient air pressure. The rotating head 46 of the support arm can now be pivoted freely with respect to the main body 34.

The first arm 14 and the second arm 16 each have a respective rotating head that acts in conjunction with a respective piston as described above for the rotating head 46 of the support arm and the piston 70 of the support arm. Button 36 (Figure 2) is used to release the first arm 16 and a second button 86 is used to release the second arm 16. 60

Figure 4a shows a cross-section according to plane B of Figure 2 for a second embodiment of the lockable joint assembly 49. In Figure 4a, the push button 36 and the second push button 86 are located on the lower side of the main body 34. This embodiment is chosen to facilitate the understanding of the mechanism. However, the embodiment shown in Figure 2 has a respective structure. As shown in Figure 4a, the second arm 16 has a second rotating head 84 that is housed in a second bushing 88. 5

Figure 4a also shows a locking device 90 for the first arm 14, which has a piston 68 ’, the gas cartridge 64, and a drive device 92. The actuation device 92 comprises a button 36 and a valve element 50 ’. To avoid repetitions, reference is made to similar elements as described above with the same reference numbers with an added quotation mark. For example, the cylinder 68 'has the same characteristics as the cylinder 68. In Figure 4a, the push button 36 is in its locked position with the cylinder 68' in gas communication only with the gas cartridge 64 and the button 86 is in its release position with cylinder 68 "in gas communication only with ambient air.

Figure 4b shows on a different level, compared to Figure 4a, that is to say with respect to a plane C that is parallel to plane B, but which is removed from the support arm 28 (see Figure 2). In Figure 4b two openings 94 ’, 94 ″ of discharge can be seen. The discharge openings 94 ', 94 "are in 15-gas communication with the second output channels 82', 82" (see Figure 4a), respectively.

Figure 5a shows the cylinder 68 which has an annular recess 98 for the O-ring 72 (not shown). Cylinder 68 has four spaces 100.1, 100.2, 100.3, 100.4. Due to these spaces, the contact area 76 of the fixing element is segmented (see Figure 3b).

Figure 5b shows a cross section of the cylinder 68 and Figure 5c shows a front view. Figure 5b is a section along the line F-F of Figure 5c.

Figure 6a shows a perspective view of the bushing 32. The second bushing 88 and bushing 42 of the support arm have an identical shape. The bushing 32 has a thread 102 for a threaded hitch with a respective thread in the main body 34 (see Figure 3a). The bushing 32 has a plurality of perforations 104.1, 104.2, ... which allow liquids or gases to reach those parts of the rotating head 30 that are captured within the bushing 32. This is particularly advantageous for cleaning and disinfecting.

Figure 6b shows a cross-section of the bushing 32, Figure 6c is a side view, and Figure 6d is a section along the G-G line of Figure 6c.

Figure 7 shows the first arm 14, the second arm 16, and the support arm 28 in a perspective view.

Figure 8 shows an alternative embodiment of a lockable joint 43 of the invention. For easy handling, a button has been replaced by a lever 106 which is pivotally connected to the main body 34 by a hinge 108.

Figure 9 shows an embodiment of a lockable joint assembly 49 of the invention in a cross-sectional view.

Referring to FIGS. 3a and 4a, the compressed gas cylinder 64 can be located within the manual control part 34. The carding screw 40 forces the compressed gas cylinder 64 against a hollow piercing element (not shown) that pierces a malleable seal of the gas cartridge 64 and connects the inside of the compressed gas cylinder 64 with the gas lines inside of or coupled to part 34 control manual. The gas flow is then controlled by the push-buttons or other valve actuators to selectively apply or release pressure on the pistons to block or unblock the ball joints. 40

The present invention is described herein using the example of a surgical retractor frame. It should be understood that there are many other applications of the present invention both in a surgical and non-surgical context, both inside and outside of medical care, in which it is desired to adjust or block articulated joints such as, but not limited to, spherical joints . It should be understood that the invention can be applied to other devices such as: Devices for holding articulated arm joints including, but not limited to: endoscopic support, support for endoscopic retractor, fan or others; support for an endoscopic instrument / device; surgical screen holder; stirrups for the legs; and clamping devices for vertical table pole. The articulated joints / fasteners used for patient positioning; Wilson frame for spinal cord applications; operating room tables; adjustment and locking mechanisms; orthopedic traction devices; and bone cement applicator. fifty

Reference numbers

10 surgical retractor system

12 surgical retractor

14 first arm

16 second arm 55

18 surgical retractor frame

20 anchor element

22 coupling anchor

24 grab bar

26 anchor element seal 5

28 support arm

30 rotating head

32 cap

34 main body

36 push button 10

38 gas cartridge retainer

40 gas cartridge chamber screw

42 support arm bushing

43 lockable joint

44 support arm lock device 15

46 swivel head of support arm

48 support arm push button

49 lockable joint assembly

50 support arm valve element

52 drilling 20

54 spring

56 annular recess

58 first gas channel

60 second gas channel

61 gas duct 25

62 gas cartridge outlet opening

64 carbon dioxide cartridge

66 cylinder inlet opening

68 cylinder

70 support arm piston 30

72 O-ring

74 fixing section

76 contact area of the fixing element

78 second annular recess

80 first output channel 35

82 second output channel

84 second rotating head

86 second push button

88 second cap

90 locking device

92 drive device

94.96 discharge opening

98 annular recess 5

100 space

102 thread

104 drilling

106 lever

108 hinge 10

A, B, C, E flat

d outside diameter of the contact area

Piston diameter piston

Dsh outer diameter of the rotating head

Dca outside diameter of contact area 15

L longitudinal axis

p gas pressure

 piston work direction

s career

V volume 20

w ring width

Claims (23)

1. Lockable joint, especially lockable ball joint, comprising

(a) a first arm (14) having a rotating head (30), (b) a bushing (32), the rotating head (30) pivotally mounted on the bushing (32), and (c) a locking device (90) arranged to block the rotating head (30) with respect to the bushing 5 (32), the locking device (90) having (i) a piston (70 ’), (ii) a source (64) of pressurized gas, and (iii) a drive device (92) arranged to reversibly disconnect the piston (70 ’) from the source (64) of pressurized gas, 10 characterized because (d) the source of pressurized gas is a gas cartridge (64).

2. Lockable joint according to claim 1, the gas cartridge (64) having an internal pressure (cartridge) of more than 4 MPa, in particular more than 6 MPa.

3. Lockable gasket according to claim 1 or 2, the gas cartridge (64) containing less than 1000 g of gas. fifteen

4. Lockable gasket according to any one of claims 1 to 3, wherein the gas cartridge (64) contains liquid carbon dioxide, pressurized air, nitrogen under pressure, nitrous oxide under pressure, or a mixture of two or three of the same.

5. Lockable joint according to any preceding claim,

- the main seal (43) having a main body (34), the main body (34) comprising the bushing (32) and the locking device (90), - the locking device (90) having a fixing element (74) that is housed in the main body (34), and - the piston (70 ’) being arranged to press the fixing element (74) against the rotating head (30).

6. Lockable joint according to claim 5, the piston and the fixing element (74) being connected, so that

- moving the piston (70 ’) in a working direction () of the piston leads to a movement of the fixing element in a working direction () of the fixing element, - the working direction () of the piston being parallel to the working direction () of the fixing element.

7. Lockable joint according to claim 5 to 6, the piston (70 ') and the fixing element (74) 30 being directly coupled, so that moving the piston (70') along a predetermined distance leads to a movement of the fixing element along the same predetermined distance.

8. Lockable joint according to claims 5 to 7,

- the main body (34) comprising a cylinder (68 ’), the cylinder (68’) having a cylinder inlet opening (66 ’), 35 - the piston (70 ’) being mobilely housed in the cylinder (68’) and comprising the fixing element in the form of a fixing section (74 ’) for pressing against the rotating head (30), and - the fixing section (74 ’) being located on the side opposite the inlet opening (66’) of the cylinder.

9. Lockable gasket according to claims 5 to 7, the main body (34) comprising a gas cartridge retaining element (38) for interchangeably housing the gas cartridge (64). 40

10. Lockable joint according to any preceding claim,

- the fixing element (74 ’) being arranged to press a contact area (76’) of the fixing element against the rotating head (30), and - having the contact area (76 ’) of the ring-shaped fixing element with a ring width of less than 1 mm

11. Lockable joint according to any of claims 5 to 10, the fixing element (74 ’) being arranged for a friction block between the fixing element (74’) and the rotating head (30).

12. Lockable joint according to any one of claims 10 or 11, the contact area (76 ’) being of the segmented fixing element. 5

13. Lockable joint according to claims 11 or 12,

- the rotating head having an outer diameter (Dsh) of the rotating head and coming into contact with the fixing element in a contact area of the ring-shaped rotating head, and - the contact area having an outside diameter (Dca) of the contact area that is greater than 0.94 times the outer diameter (Dsh) of the rotating head. 10

14. Lockable joint according to any preceding claim,

- the first arm having a longitudinal axis (L) of the arm and - the outer diameter (Dca) of the contact area and the longitudinal axis (L) of the arm forming a substantially constant effective angle (α) of less than 20 °.

15. Lockable joint according to claim 8, 15

- the gas cartridge (64) having an outlet opening (62) of the gas cartridge, - the cylinder (68 ') and the gas cartridge being in gas communication through a gas conduit (61') between the outlet opening (62) of the gas cartridge and the inlet opening (66 ') of the cylinder, and - the gas line (61 ’) having a volume (V) of less than 1000 mm3, in particular less than 500 mm3.

16. Lockable joint according to any preceding claim, the piston (70 ') having a stroke (s) of less than 2 mm, in particular of less than 1 mm.

17. Lockable joint according to any preceding claim, the piston having a piston diameter (D piston) of more than 20 mm.

18. Lockable joint assembly, comprising

(a) a lockable seal (43) according to any preceding claim, (b) a second arm (16) having a second rotating head (84), (c) a second bushing (88), the second rotating head (84) pivotally mounted on the second bushing (88), and (d) a second locking device arranged to block the second rotating head (84) with respect to the second bushing (88), the second locking device having 30 (i) a second piston (70 ") in disconnectable gas communication with the gas cartridge (64), and (ii) a second drive device (86, 50 ") arranged to reversibly disconnect the second piston (70") from the pressurized gas cartridge (64).

19. Lockable joint assembly according to claim 18, the second arm (16) being disposed on the side opposite the first arm (14). 35

20. Lockable joint assembly according to any of claims 18 or 19, comprising

(a) a support arm (28) having a rotating head (46) of the support arm, (b) a bushing (42) of the support arm, the rotating head (46) of the support arm being pivotally mounted on the bushing (42) of the support arm, (c) a support arm lock device (44) arranged to lock the rotating head (46) of the support arm 40 relative to the bushing (42) of the support arm, the arm lock device (44) having of support (i) a piston (70) of the support arm in disconnectable gas communication with the gas cartridge (64), and (ii) a support arm drive device (48, 50) arranged to reversibly disconnect the piston (70) from the support arm of the gas cartridge (64).

21. Surgical retractor frame, comprising:

(a) a lockable joint assembly (49) according to any one of claims 18 to 20, (b) the first arm (14) being adapted to accommodate a surgical retractor (12), and (c) an anchoring element (20) for mounting the lockable joint assembly (49) on an operating table, 5 (d) the anchoring element (20) being releasably mounted on the support arm (28).

22. Surgical retractor system, comprising the surgical retractor frame (18) according to claim 21 and at least one surgical retractor (12) releasably mounted on the first arm (14).

23. Procedure for fixing a lockable joint (43), especially a lockable ball joint, having 10

- a first arm (14), the first arm having a rotating head (30), - a bushing (32), the rotating head (30) pivotally mounted on the bushing (32), - a locking device arranged to block the rotating head with respect to the bushing, the locking device having one piston, 15 a gas cartridge, in particular a carbon dioxide cartridge, and an actuator arranged to reversibly disconnect the piston from the gas cartridge, which comprises the stages of: - actuate the actuator, thereby eliminating the pressure of the piston so that the first arm can be pivoted with respect to the bushing and 20 - release the drive device, thereby putting the piston under pressure by bringing it into gas communication with the gas cartridge so that the locking device blocks the rotating head with respect to the bushing.