GB2186652A

GB2186652A - Releasable locking arrangement for taper connections

Info

Publication number: GB2186652A
Application number: GB08702913A
Authority: GB
Inventors: Klaus Jehmlich
Original assignee: Medizin und Labortechnik Leipzig VEB
Current assignee: Medizin und Labortechnik Leipzig VEB
Priority date: 1986-02-19
Filing date: 1987-02-10
Publication date: 1987-08-19
Also published as: GB2186652B; GB8702913D0; SE464335B; DD246030A1; SE8605125L; DE3640955A1; SE8605125D0

Abstract

A male tapered part 6 is attached to a female tapered part 5 by claws 16 arranged at the free ends of tongues (2) on a surrounding member 1, the claws entering an annular groove (17) in the male part 6; the claws 16 are moved radially inwardly (locked) and outwardly (released) by peripheral wedge surfaces 10 on the female part 5. Member 1 and part 5 are connected by a spring 3 which permits relative axial and rotational movement. The wedge surfaces are separated by stops 13 which limit the rotation of the member 1. The connections are for use in medical flexible-tube systems such as inhalation anaesthetic and breathing equipment. <IMAGE>

Description

SPECIFICATION Releasable locking arrangement for taper connections The invention relates to a releasable locking means for taper connections with axial compensation for play. Such taper connections are used in medical flexibletube systems and particularly in the breathing circuit of inhalation anaesthetic and breathing equipment.

According to ISO/DIS 5367 and TGL-RGW 1454, taper connections with a nominal width of 15.22 and 30 and a taper of 1:40 or 1:20 are prescribed for taper connections in the breathing circuit of inhalation anaesthetic and breathing eguipment. The 1:40 taper in particular, with an angle of inclination of 0 43' +2.2', involves the risk of release of the taper connection if the tolerance limits are reached or exceeded or even after wear. Associated with this are extremely dangerous conditions for the artificial respiration patient, which must be prevented.

An equal number of claws is arranged oppositely situated in each case. If the claw member is pressed offset radially and by 900 to the claws, these expand and the taper connection can be undone.

In this taper connection with securing against disconnection, all the tolerances have to be taken up by the sealing ring. Since this soon loses its resilience, however, as a result of the necessary sterilization operations, leakages will occur after a relatively short time.

Nor is there any possibility of eliminating these leakages because no means for axial compensation are provided.

The present invention seeks to overcome or reduce the disadvantages mentioned and to provide a releasable locking means for taper connections, the tightness of which is in no way dependent on an annular seal and is ensured by axial compensation.

The present invention also seeks to provide a releasable locking means for taper connections which, in accordance with international standards, does not use any resilient sealing element and eliminates any leakages caused by manufacturing defects, soiling and wear. In addition, the leakproof taper connection should also be able to be opened more favourably even after defects have been removed.

According to the present invention there is provided a releasable locking arrangement for taper connections having a female tapered part and a male tapered part, comprising a claw member which is capable of axial and rotational movement in relation to the female tapered part and which is constructed in the form of a closed ring and provided with detent tongues arranged inwardly thereof, and peripheral wedge surfaces on the female tapered part resting on each of which is a detent tongue, the detent tongues having claws at their free ends and, depending on the position of the claw member, are either expanded or snapped into an annular groove on the male tapered part by their claws.

In a preferred embodiment the arrangement has a compression spring with torsional behaviour which is disposed between the claw member and the female part and one end of which is fixed to the female part and held against torsion and the other end of which is connected to the claw member. It is advisable to secure one end of the spring to the inner marginal portion of the wedge surfaces or planes at the entry side of the female taper and to connect the other end of the spring to a guiding portion of the claw member.

Furthermore, between the wedge surfaces there are twosided stops which form the limits for the rotary movement of the detent tongues so that, when hearing against the one side, these assume the snapped-in position and when bearing against the other side they assume the expanded position. An advantageous solution is provided if there are four wedge planes and four stops arranged between them so that the rotatability of the claw member is limited to 900.

In a preferred arrangement the sum of all the frictional forces acting as a result of the detent tongues resting on the wedge surfaces is smaller than the torsional force of the compression spring and before the two tapered parts are fitted together, the detent tongues always rest against the respective stop sides of the stops as a result of the torsional behaviour of the compression spring.

The advantages of the above locking arrangement are to be seen, in particular, in the axial compensation for the defects resulting from manufacture, wear and soiling but also in better freedom of maintenance and a favourable formation from the assembly point of view as well as the possibility which is afforded of introducing a torque for the facilitated releasing of jammed taper connections.

A preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure 1 shows a sectional view of a taper connection with a claw member in the locking position; Figure 2 shows a view corresponding to Figure 1 in the unlocked state; Figure 3 shows a section A on Figure 1; and Figure 4 shows a section B on Figure 2.

First let it be mentioned that in the two Figures 1 and 2, only one half section of a taper connection in the same position can be seen in each case but these very clearly show the locking means according to the invention in two positions offset by 900.

As Figure 1 shows, the claw member 1 formed according to the invention is a closed outer ring which has detent tongues 2 in the interior. It is connected, by a compression spring 3 with torsional behaviour, to a connecting member 4 with a female taper 5, for axial displacement and rotation, in which taper there is the male taper 6 of a connecting member 7. The compression spring 3 is fitted, by bent ends 8, 9, on the one hand to the claw member 1 and on the other hand to the female connecting member 4 so that the claw member 1 is prestressed in the direction of rotation and axially in relation to the connecting member 4.

Furthermore, the connecting member 4 is provided, at the entry side of the female taper 5, with wedge planes 10 which extend at the periphery and on each of which a detent tongue 2 is mounted with prestressing. In one preferred embodiment, the one end 8 of the spring is secured to the inner marginal portion 11 of this wedge #plane 10 while the other end 9 of the spring is connected to a guiding portion 12 of the claw member 1. Disposed between the beginning and end of each of the wedge planes 10 is a two-sided stop 13 of which, therefore, with preferably four wedge planes 10, there are an equal number of stops 13.These stops 13 form the limits for the rotary movement of the detent tongues 2 which, according to Figures 1 and 3 are located at one side 14 of the stops in the "lock" position and according to Figures 2 and 4 at the other side 15 of the stops in the "open" position.

The free ends of the detent tongues 2 are provided with claws 16 which, depending on the rotary movement of the claw member 1 which is effected, are either in a position lifted from the male taper 6 or in a position situated behind it, preferably in an annular groove 17.

If a taper connection is now established, the detent tongues 2, which are bearing against the side 14 of the stops as a result of the torsional behaviour of the compression spring 3, slide in the axial direction of the two connecting members 4, 7 over the wedge planes 10 and so the claws 16 slide in the same direction over the male taper 6. In the course of this, the detent tongues 2 at first expand with increasing fitting together of the two tapers 5, 6 until finally the male taper 6 comes to bear against the female taper 5. The claw member 1 is now moved further axially, against the action of the compression spring 3, until the claws 16 of the detent tongues 2 engage in the annular groove 17. When the "lock" position is reached, a taper connection is secured under constant axial spring pressure with compensation for any possible faulty tolerances.

In order to release the taper connection, the claw member 1, which may also have grip plates or be provided with knurling, is turned counter-clockwise, seen from the end 18 of the flexible tube. As a result, the detent tongues 2 move on the wedge planes 10 against the torsional force of the compression spring 3 to the side 15 of the stops and assume an expanded position. When the "open" position is reached, the taper connection can be undone.

If this taper connection is relatively tight, the stops 13 enable the rotary movement of the claw member 1 to be transmitted to the connecting member 4 which facilitates the releasing of the female taper 5 from the male taper 6. After the release of the taper connection, the claw member 1 returns automatically to the initial "lock" position as a result of the effective spring force component.

The claw-shaped formation of the free ends of the detent tongues is also designed to limit the axial backward movement of the claw member 1 caused by the compression spring 3. Therefore, the claws 16 are at least so large that the locking means is held in a predetermined end position by impact against the marginal portion 11 of the wedge planes 10.

Claims

1. A releasable locking arrangement for taper connections having a female tapered part and a male tapered part, comprising a claw member which is capable of axial and rotational movement in relation to the female tapered part and which is constructed in the form of a closed ring and provided with detent tongues arranged inwardly thereof, and peripheral wedge surfaces on the female tapered part resting on each of which is a detent tongue, the detent tongues having claws at their free ends and, depending on the position of the claw member, are either expanded or snapped into an annular groove on the male tapered part by their claws.

2. A locking arrangement according to Claim 1 wherein the detent tongues rest on the wedge surfaces under slight prestressing.

3. A locking arrangement according to Claim 1 or 2, wherein disposed between the claw member and the female tapered part is a compression spring with torsional behaviour, one end of the spring being fixed to the female tapered part and secured against torsion and the other end of the spring being connected to the claw member, so that this is prestressed in the direction of rotation and axially in relation to the female tapered part.

4. A locking arrangement according to Claim 3, wherein one end of the spring is secured to an inner marginal portion of the wedge surfaces at the entry side of the female taper, and the other end of the spring is connected to a guiding portion of the claw member.

5. A locking arrangement according to any of Claims 1 to 3 wherein, between the beginning and end of each of the wedge surfaces there are provided two-sided stops, the stop sides of which form limits for the rotary movement of the detent tongues.

6. A locking arrangement according to Claim 5, wherein there are four wedge surfaces and four stops provided between them so that the rotation of the claw member is limited to 900.

7. A locking arrangement according to Claim 5 or 6, wherein the detent tongues are located in the "locked" position at one side of the stops and in the "open" position at the other side of the stops.

8. A locking arrangement according to any of Claims 5 to 7, wherein the sun of all the frictional forces acting as a result of the detent tongues resting on the wedge surfaces is smaller than the torsional force of the compression spring and before the two tapered parts are fitted together, the detent tongues always rest against the respective stop sides of the stops as a result of the torsional behaviour of the compression spring.

9. A releasable locking arrangement substantially as herein described with reference to the accompanying drawings.