GB2400503A

GB2400503A - Sealed clamp for sealing round a cable

Info

Publication number: GB2400503A
Application number: GB0406297A
Authority: GB
Inventors: Karlheinz Binder
Original assignee: Pflitsch GmbH and Co KG
Current assignee: Pflitsch GmbH and Co KG
Priority date: 2003-03-21
Filing date: 2004-03-19
Publication date: 2004-10-13
Also published as: GB0406297D0; FR2852657B3; ES2241484A1; ES2241484B1; DE10312749B4; ITMI20040526A1; FR2852657A1; DE10312749A1

Abstract

A sealed clamp for sealing round a cable or the like comprising: a casing 1; a deformable clamping ring 5 inside the casing; a screw ring 3 for actuating clamping; and a seal 6 inside the casing; wherein a cable may run through the components of the sealed clamp and the screw ring 5 has an internal spherical surface 7 which, in use, engages an external spherical surface 8 on the clamping ring 5 to urge the clamping ring 5 onto a cable when the screw ring 3 is screwed onto the casing 1. The clamping ring 5 may be formed with segments connected by a web 9. The seal 3 may extend the length of the clamping ring 5 and may have internal ribs for engaging a cable. The seal 6 and the clamping ring 5 may be formed in one piece. A groove 10 in the end of the casing 1 may receive the end of the seal 6.

Description

Screw fitting for sealed line passages The invention concerns a screw

fitting for sealed line passages with a double nipple, a pressure screw which can be screwed thereon with axial passage opening and an annular clamping ring and sealmg insert inserted between the double nipple and pressure screw, where a hne can be passed through the parts and the clamping ring is deformable radially inwards by the screwed together components of double nipple and pressure screw, ensuring tension relief and sealing of the line.

Such screw fittings are used in line passages through housing walls, for example in electrical equipment, to allow a sealed introduction of cables or similar. In such screw fittings, in order to be able to apply high clamping forces to the cable or line and create a certain tension relief, at the end of the clamping insert are provided tooth-like formations which are forced towards each other by the screwing of the pressure screw so that the passage cross-section for the cable or line is constricted. In such designs it is necessary to provide different screw fittings for different dimension ranges as the usual screw fittings cannot be reduced arbitrarily in diameter when the pressure screw is applied. Furthermore it is also usual for the pressure screws to be splayed conically on their inside, at their opening facing away from the double nipple, and the clamping ring also to be splayed conically in order to promote the radially inwards movement when screwing on the pressure screw. This however means that to tighten the screw fitting on a line, the pressure screw must be turned several times about its longitudinal axis following through thread until the required pressure force is exerted on the cable or similar. This procedure is time- consuming and therefore disadvantageous.

Starting from this prior art, the invention is based on the object of creating a screw fitting of the generic type in which just a few turns of the pressure screw suffice to achieve an excellent clamping effect and a very large clamping range can be provided for clamping the lines.

To achieve this object the invention proposes that the pressure screw, on the inside in the end area co-operating with the clamping ring, has a spherical cavity and the clamping ring an adapted spherical outer casing surface.

Due to the spherical design of the cavity and correspondingly adapted spherical design of the outer casing surface of the clamping ring, just a few turns of the pressure screw suffice to achieve a substantial reduction in the passage channel of the clamping ring so that the clamping ring can be tightened onto the cable in a short time with little effort. Also the spherical design ensures a considerably expanded clamping range as despite the relatively short length of the clamping ring a substantial constriction is achieved in the passage channel for the cable or similar line.

Preferably it can be provided that the cavity and the clamping ring are formed spherical over their entire length.

For adequate operation it would indeed be sufficient if the cavity of the clamping screw, starting from its thread to the opening facing away from the double nipple, first runs tangentially out from the thread and then in an arc towards the opening since this would achieve an adequate clamping of the clamping ring with the spherical outer casing surface.

If however both parts are formed spherical over their entire length, the clamping ring can be inserted captive in the cavity of the pressure screw as the arc clamped by the cavity amounts to more than the shape of a semicircle if the arc form is considered from the connection of the thread of the pressure screw over its entire course to the opposite end. It is thus easily possible to insert the clamping ring in the cavity so this is held captive.

Particularly preferably it is provided that the clamping ring comprises individual segments which are spaced evenly apart in the peripheral direction.

The segment spacing can be approximately equal to the segment width (in the unclamped state of the screw fitting) but also the segments can be formed very densely and differently so that for example when the pressure screw is turned they constrict the opening overlapping.

The individual segments arranged spaced apart, or certain overlapping segments, allow to a greater extent the provision of a large clamping range for the screw fitting, so that starting from a maximum diameter even very thin lines can be sealed and tension-relieved with a screw fitting.

In order to guarantee the cohesion of the clamping ring, it is also provided that the segments are connected together via thin material webs.

Here for the function it is advantageous if the material webs are provided close to the end of the clamping ring adjacent to the double nipple.

Particularly preferably it is provided that the clamping ring or the parts forming the clamping ring comprise hard plastic.

In order to achieve a good force application of the clamping ring when clamping the screw fitting to the line, it can be provided that the clamping ring or parts forming the clamping ring are tapered on the end facing the pressure screw.

Preferably it is also provided that the sealing insert is formed by a hose which runs over the axial length of the clamping ring.

The sealing insert Is inserted in the clamping ring on the inside.

It can also be provided that the sealing insert is formed by a moulding which has an essentially cylindrical hollow channel for the line to be passed through.

Here it can be provided that the moulding on the outside has projections, ribs or material protrusions which engage between the individual segments.

This embodiment can be advantageous for the effective seal of the screw fitting.

It can also be provided that the sealing insert is formed by a sealing compound connected with the clamping ring.

It is for example possible for the sealing insert and clamping ring to be formed by a multi- component injection moulding of plastic.

Preferably it is also provided that the sealing insert consists of soft plastic material.

It is however also possible that the clamping ring and sealing insert are made of one piece from the same elastic material and the function of the clamping ring is ensured by defined geometry.

To prevent damage to the line casing from the parts of the clamping ring engaging thereon, it can be provided that the sealing insert protrudes axially over the clamping ring at its end facing the pressure screw.

It can also be provided that the sealing insert extends over the entire length of the screw fitting.

An embodiment example of the invention is shown in the drawing and described in more detail below. This shows: Figure 1 a screw fitting according to the invention in exploded view; Figure 2 the screw fittmg in the usage state in the longitudinal section viewed along line II/II in figure 3; Figure 3 the screw fitting in top view; Figure 4 a detail of the screw fitting in front view, partly cut away; Figs. 5 to 7 a variant of a clamping ring in different views.

The drawing shows a screw fitting for sealed line passages. It has a double nipple 1 with threads formed on both ends and polygonal tool fitting point 2, and a pressure screw 3 which can be screwed thereon also with tool fitting point 4 and internal thread. The pressure screw has an axial passage opening which is preferably adapted to the clear width of the passage opening of double nipple 1.

Between double nipple 1 and pressure screw 3 is arranged an annular clamping ring 5 and a sealing insert 6.

In the nominal mounting position as shown for example in figure 2, a line can be passed axially through the components. By turning the pressure screw 3 relative to the double nipple 1, the clamping ring 5 is deformed radially inwards by the action of the pressure screw 3 so that tension relief and, due to the sealing insert 6, a good seal of the line are achieved.

As is evident in particular from figures 2 and 4, the pressure screw 3 on the inside has in the end area co-operating with the clamping ring 5 a spherical cavity 7 while the clamping ring has a spherical outer casing surface 8 adapted to this spherical form. In the embodiment example both the cavity 7 and the outer surface 8 are formed spherical over their entire length so that the ends of the sealing insert facing the thread of the pressure screw 3 do not connect tangentially to the cylindrical threaded area of the pressure screw 3, but the ball form is constricted in relation to this so that the clamping ring 5 in the position according to figure 2 is held captive in the pressure screw 3 even when this is detached from the double nipple 1.

The clamping ring 5 comprises a multiplicity of individual segments which have side faces aligned parallel to the centre longitudinal axis of the screw fitting and are formed approximately trapezoidal m cross section. The individual segments are spaced apart evenly in the peripheral direction, where the segment spacing is approximately equal to the segment width when the screw fitting is unclamped, as shown for example in figure 1. The segments are connected together via thin material webs 9 so that the individual parts of the clamping ring 5 are captively connected together. The material webs 9 are arranged close to the end of the clamping ring 5 facing double nipple 1.

Preferably the clamping ring 5 comprises relatively hard material, preferably plastic. Also the segments which form the clamping ring 5 are tapered towards the end facing the pressure screw 3, as shown in particular in figure 2.

The sealing insert 6 in the embodiment example is formed by a moulding which is essentially overlapped by the clamping ring 5 and has an essentially cylindrical hollow channel for the line to be passed through. The moulding on the outside has projections, ribs or material protrusions which engage between the individual segments of the clamping ring 5. Instead of the multi-part structure shown in figure 1, a one-piece design of sealing insert 6 and clamping ring 5 is possible where these parts for example are formed by multi- component injection moulding. The sealing insert 6 preferably consists of rubber elastic material or elastomer soft plastic. As is clear in particular from figure 2, the double nipple 1 in its end facing the sealing insert 6 has a peripheral groove 10 in which engages a collar- like end of the sealing insert 6.

As is clear in particular from figure 2, the sealing insert 6 also protrudes axially over the clamping ring 5 at its end facing the clamping screw at the upper end. This ensures that on clamping of the screw fitting the finger-like ends of the clamping ring S do not lie directly on the casing of the line but with the material of the sealing insert 6 in between.

In the design of clamping ring 5 according to figure 5 to 7, the segments are arranged close together and formed - like helical gearing - such that they overlap when the pressure screw is tightened and constrict the passage channel.

The invention provides a screw fitting which is simple to operate, in which just a few turns of the pressure screw 3 suffice to clamp the screw fitting and a very large clamping range is provided for the lines to be passed through, and with which an excellent seal and tension relief of the line can be achieved.

The invention is not restricted to the embodiment example but is variable in many ways

within the context of the disclosure.

All new individual features or combinations thereof disclosed in the description and/or drawings are considered essential to the invention.

Claims

Claims 1. Screw fitting for sealed line passages with a double nipple (1),

a pressure screw (3) which can be screwed thereon with axial passage opening and an annular clamping ring (5) and sealing insert (6) inserted between the double nipple (1) and the pressure screw (3), where a line can be passed through the components and the clamping ring (5) is deformable radially inwards by the screwed together components of double nipple (1) and pressure screw (3), ensuring tension relief and sealing of the line, characterised in that the pressure screw (3) on the inside in the end area co-operating with the clamping ring (5) has a spherical cavity (7) and the clamping ring (5) has an adapted spherical outer casing surface (8).
2. Screw fitting according to claim 1, characterised in that the cavity (7) and the clamping ring (5) are formed spherical over their entire length.
3. Screw fitting according to claim 1 or 2, characterised in that the clamping ring (5) comprises individual segments spaced evenly apart in the peripheral direction.
4. Screw fitting according to any of claims 1 to 3, characterised in that the segment spacing is approximately equal to the segment width (in the unclamped state of the screw fitting) and/or that the segments are close together and formed so that on tightening on the pressure screw (3) they overlap, constricting the opening.
5. Screw fitting according to one of claims 3 or 4, characterised in that the segments are connected together via thm material webs (9).
6. Screw fitting according to claim 5, characterised in that the material webs (9) are provided close to the end of the clamping ring (5) adjacent to the double nipple (1).
7. Screw fitting according to any of claims 1 to 6, characterised in that the clamping ring (5) or the parts forming the clamping ring (5) comprise hard plastic.
8. Screw fitting according to any of claims I to 7, characterised in that the clamping ring (5) or the parts forming the clamping ring (S) are tapered towards the end facing the clamping screw (3).
9. Screw fitting according to any of claims 1 to 8, characterised in that the sealing insert (6) is formed by a hose running over the axial length of the clamping ring (S).
10. Screw fitting according to any of claims I to 8, characterised in that the sealing insert (6) is formed by a moulding which has an essentially cylindrical hollow channel for the line to be passed through.
11. Screw fitting according to any of claims 3 to 10, characterised in that the moulding has on the outside projections, ribs or material protrusions which engage between the individual segments.
12. Screw fitting according to any of claims 1 to 11, characterised in that the sealing insert (6)is formed by a sealing compound connected with the clamping ring (S).
13. Screw fitting according to any of claims 1 to 12, characterised in that the sealing insert (6) comprises soft plastic material.
14. Screw fitting according to any of claims 1 to 13, characterised in that the clamping ring (S) and the sealing Insert (6) consist of one piece of the same elastic material and in particular the function of the clamping ring (S) is achieved by a defined geometry thereof.
IS. Screw fitting according to any of claims 1 to 14, characterised in that the double nipple (1) in its end facing the sealing insert (6) has a peripheral groove (10) in which engages the end of the sealing insert (6).
16. Screw fitting according to any of claims 1 to 15, characterised in that the sealing insert (6) protrudes axially over the clamping ring (5) at its end facing the pressure screw (3).
17. Screw fitting according to any of claims 1 to 16, characterised in that the sealing insert (6) extends over the entire length of the screw fitting.
18. Screw fitting for sealed line passages with a double nipple substantially as hereinbefore described with reference to the accompanying drawings.