GB2577330A

GB2577330A - Cable clamp

Info

Publication number: GB2577330A
Application number: GB1815526.7A
Authority: GB
Inventors: Chapman Paul; Cooper Brynn
Original assignee: Technetix BV
Current assignee: Technetix BV
Priority date: 2018-09-24
Filing date: 2018-09-24
Publication date: 2020-03-25
Anticipated expiration: 2038-09-24
Also published as: GB2577330B; GB201815526D0; NL2023774A; NL2023774B1; DE102019125508A1

Abstract

A cable clamp (10, figure 1) comprising a clamp body 12 defining an opening (24, figure 4) for receiving a cable 20 (preferably coaxial) and a closure portion 14 for securing over the opening, and further comprising at least one spring member (22) comprising a plurality of resilient ribs 30, 70 and locatable within the opening. Preferably two spring members are used, one spring member (22', figure 18) is positioned in the closure portion and one spring member (22, figure 17) is positioned in the body; the ribs of one spring member may be upwardly depending and the ribs of the other spring member may be downwardly depending so that the ribs of one spring member are at least partially positioned within the ribs of the other spring member. The ribs may be paired to provide a U-shaped profile, and all depend from a spine (72, figure 11a). The clamp body may comprise jaws (54, 56, figure 8) against which the cable may be clamped.

Description

Title: Cable Clamp

Field of Invention

This invention relates to a cable clamp, particularly, but not exclusively, for use with coaxial cables.

Background to the Invention

Wall outlets exist in the home as an interface between the coaxial cabling that exists in the wall, floor and ceiling and the electronic devices around the home. The cabling o in the wall serves to distribute the signals travelling between devices. The cable within the walls, floor or ceiling needs to be connected to the electronic devices using a connector. However there is often insufficient space for a connector in the volume allocated for the wall outlet, and even less likely that there is enough spare cable within the wall to permit fitting of a connector using commonly available tools.

Is Clamp-type connectors are used to mitigate these issues.

It is important to have effective shielding of the joint between the wall outlet and the cabling inside the wall. A clamp-type connector aims to ensure good shielding effectiveness by a clamping mechanism, which surrounds the shielding on the cable and crushes it between the jaws of the clamp. This crushing action provides excellent mechanical grip.

The coaxial cabling inside the wall is not of a uniform type and the range of sizes of coaxial cable that must be accommodated is often large. This has several drawbacks when implementing a traditional clamp type design, in particular there is no optimal size for the clamp given the variety of sizes of coaxial cable with which the clamp might be used and the dielectric material of the coaxial cable is prone to creep over time, which results in reduced preload imparted onto the cable by the clamp, decreasing the effectiveness of the shielding over time.

Summary of the Invention

The present invention provides a cable clamp comprising a clamp body defining an opening for receiving a cable, such as a coaxial cable, and a closure portion for securing over the opening, and further comprising at least one spring member comprising a plurality of resilient ribs and locatable within the opening.

Two spring members may be provided, with preferably one spring member positioned within the clamp body and one spring member positioned within the closure portion.

Where two spring members are provided, preferably the ribs of one spring member are upwardly depending and the ribs of the other spring member are downwardly depending so that the ribs of one spring member are at least partially positionable to within the ribs of the other spring member, typically as the clamp is closed to secure a cable.

Preferably one spring member is positioned in the closure portion such that the spring member locates within the opening when the closure portion is secured in position after insertion of a coaxial cable into the clamp body.

One spring member may be positioned in the cable body, and thus engage with a coaxial cable as the coaxial cable is inserted into the opening. Where two spring members are provided, desirably one spring member is positioned in the closure portion and one spring member is positioned in the clamp body.

The closure portion and/ or the clamp body may be formed with grooves to receive the ribs.

The ribs may be connected as pairs to provide a substantially U-shaped profile and typically three pairs of connected ribs will be provided spaced along a common axis.

Each rib may incorporate a curved region so as to increase preload applied to a cable.

The ribs may depend from a spine, the ribs positioned along two opposing sides of the spine, this arrangement being particularly preferred for a spring member positioned in the closure member.

The spine may incorporate at least one aperture, and preferably two apertures, to enable the spring member to be attached to the closure member.

The spring member may further comprise a deflectable member depending from one end of the spine, the deflectable member typically being bifurcated. The deflectable member is preferably resilient.

The ribs may be aligned along an axis and connected to each other using first and second connecting members, each connecting member extending along the direction i) of the axis and connecting to edges of the ribs. This arrangement is particularly preferred for a spring member positioned in the clamp body. Typically the connecting members will each incorporate at least one aperture to enable the spring member to be secured to the clamp body.

Is In a particularly preferred embodiment, a first spring member may be positioned in the closure portion and a second spring member may be positioned in the clamp body, wherein the first spring member comprises ribs depending from a spine, the ribs positioned along two opposing sides of the spine, and the second spring member comprises ribs connected as pairs and aligned along an axis, the pairs of ribs connected to each other using first and second connecting members, each connecting member extending along the direction of the axis and connecting to edges of the ribs.

The spring member may further comprise protrusions, or shorting bars, depending from the ribs and configured to contact a region surrounding the spring member, such as the clamp body. This allows a short, low impedance path to ground to be provided between the spring member and the adjacent region in which the spring member is located.

The invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 shows a cable clamp in accordance with the present invention prior to insertion of a coaxial cable; Figure 2 shows a perspective view of the coaxial cable inserted into the clamp with the clamp in an open condition; Figure 3 shows the clamp in a closed position; Figure 4 shows an exploded view of the clamp; Figure 5 shows a base forming part of the clamp; Figures 6 (a) and (b) show respectively a cross-section and perspective view of a spring member positionable within the base; Figure 7 shows a partial cross-section through the base when the spring member s in position; Figure 8 shows a cutaway view through the base when the spring member is in position; Figure 9 shows a view from an outer end of the base when the spring member is in position and a coaxial cable inserted; Figures 10 (a) and (b) show respectively plan and perspective views of a closure portion of the clamp; Figures 11 (a) and (b) show respectively a perspective view from one side and a perspective view from underneath of a spring member used with the closure portion; Figures 12 (a) and (b) show respectively plan and perspective views of the securing portion with spring member in position; Figure 13 shows a perspective view of the securing portion and spring member combined; Figure 14 is a perspective view illustrating how spring members in the securing portion and base interlink, with the base omitted for clarity; Figure 15 shows a section through the clamp; Figure 16 shows the clamp in use to grip a coaxial cable; Figure 17 shows a second embodiment where a single spring member s used in the base of the clamp; Figure 18 shows a third embodiment where a spring member is only associated with the securing portion; Figure 19 shows a fourth embodiment where the spring member is associated with the securing portion, without grooves or a spring member in the base of the clamp; and Figure 20 shows a fifth embodiment illustrating a multiple clamp arrangement.

Description

Figures 1 to 16 illustrate a first embodiment of a cable clamp in accordance with the invention used for securing an end of a coaxial cable.

The cable clamp 10 comprises a clamp base or body 12 and a separable clamp closure portion or lid 14 with the clamp shown in an open position in Figure 1 prior to receiving a coaxial cable 20. Lid 14 locates in body 12 by means of a push-fit connection to secure coaxial cable 20 within clamp 10, lid 14 sitting flush with a top surface 16 of body 12 in the closed clamp position shown in Figure 3. Typically body 12 and lid 14 are made from metal.

As can be seen in Figure 4, spring members 22, 22' are respectively associated with body portion 12 and lid 14, the spring members being shown in more detail in Figures 6 and 11 and each comprising a plurality of resilient ribs. Springs 22, 22' are i5 electrically conductive, typically being formed from metal. Body 12 is formed with an opening 24 which is substantially cuboid and incorporates three grooves 26, 26' 26" in which ribs 30 of spring 22 locate to ensure spring 22 is positioned correctly, the grooves allowing the ribs to deflect downwardly. Fixing points 32 are provided on body 12 so as to allow spring 22 to be secured in place.

Spring 22 consists of three pairs 34 of connected resilient ribs, each pair of ribs presenting a substantially U-shaped profile. Other numbers of ribs can be used. Each rib is shaped with a bend 36 towards its lower end, see Figure 6 (a). At base 40 of each connected pair 34 of ribs, two downwardly extending protrusions 42 or shorting bars, are provided, these protrusions acting to support spring 22 within body 12 and in use providing a low impedance path between spring 22 and body 12 so maximising shielding effectiveness. The three pairs 34 of conjoined ribs are connected to each other at their upper free end by portions 50, 50', see Figure 6 (b), so as to provide two securing lips which can be secured to fixing points 32 on body 12.

Figure 7 shows a cross-section illustrating the positioning of spring 22 within groove 26, with a cutaway view shown in Figure 8. Jaws 54, 56 are disposed at the open and closed end of opening 24 against which a coaxial cable will be clamped.

As shown in Figure 9, bends 36 of ribs 30 protrude above the height of jaws 54, 56. When a coaxial cable is positioned in opening 24, spring 22 contacts with coaxial cable 20 before the cable contacts jaws 54, 56 and spring 22 deflects, applying preload to the coaxial cable 20 prior to closure of the clamp lid 14.

Figures 10 to 13 show lid 14 in detail, both alone and in combination with spring 22'. Lid 14 is formed from metal with three centrally interconnected grooves 62 which are configured to receive spring 22'. Fixing points 64 are provided within lid 14 with io corresponding apertures 66 in spring 22' so that spring 22' can be secured to lid 14 with suitable fastening elements.

Spring 22' comprises six resilient ribs 70 formed as three pairs of opposing ribs connected along a central spine 72 and each pair of ribs having a substantially U-shaped profile. At one end of spine 72 is attached a bifurcated leaf 74. The placement of spring 22' within lid 14 is shown in Figures 12 (a) and (b) and Figure 13.

When lid 14 is positioned to secure and clamp a coaxial cable as shown in Figure 3, springs 22 and 22' will interconnect as shown in Figures 14, 15 and 16.

When lid 14 is secured in position, springs 22 and 22' inter-engage, with ribs 70 of spring 22' nesting within ribs 30 of spring 22, see Figures 14 and 15. The ribs define a channel 75 for receiving a coaxial cable. As lid 14 is urged into position so as to contact body or base 12 and close the clamp, base spring 22 which protrudes outside the area of jaws 54, 56 deflects to apply preload to coaxial cable 20. Figure 16 shows the lid during this process but before full contact is established. Preload is also applied as ribs 70 urge against ribs 30 during downward motion of lid 14. This results in a high gripping force between coaxial cable 20 and the clamp assembly formed by lid 14 and body 12. Spring 22 will contact the coaxial cable when the outside diameter of the coaxial cable falls within the range that the clamp is scaled for and that can be received within jaws 54, 56.

The electrically conductive springs 22, 22' provide a low impedance path between each other and also between body 12 and lid 14 so maximising shielding effectiveness. Further shorting bars 42 on spring 22 form a short, low impedance path to ground between spring 22 and clamp body 12. The deflectable resilient ribs 30, 70 allow preload to be applied to the coaxial cable to improve gripping and bifurcated leaf 74 of top spring 22' acts to apply further preload by deflecting and also provides a low impedance path between top spring 22' and base 12.

Alternative embodiments are shown in Figures 17 to 20. Effective gripping can be to obtained just by using one spring member with resilient ribs and in Figure 17 the embodiment just has base spring 20, located within grooves in body 12 with lid portion 14 not having a separate spring.

The embodiment shown in Figure 18 omits a base spring and relies on spring 22' Is associated with lid portion 14. Whilst grooves are shown within body 12, these can be omitted as shown in the embodiment of Figure 19 where there are no grooves or spring in the base portion.

As will be appreciated by those skilled in the art, different combinations of the clamping arrangements shown can be used within a connector, and multiple clamps can be used together, see for example Figure 20 where two clamps according to the first described embodiment are shown situated side-by-side, with the two base springs joined by additional shorting bar 80, thus adding parallel impedance and so increasing shielding effectiveness.

The coaxial cable connection clamps described can be used on, for example, a range of wall outlets that provide the interface between bare, stripped coaxial cable and the internal circuitry of the wall outlet itself. The clamps described have a high shielding effectiveness whilst being robust enough to prevent the cable from being pulled out during installation. The clamps described provide good mechanical gripping, high levels of retention strength, very high shielding effectiveness, resilience against creep and good ability to accommodate a large range of cable sizes.

Claims

Claims 1. A cable clamp comprising a clamp body defining an opening for receiving a cable and a closure portion for securing over the opening, and further comprising at least one spring member comprising a plurality of resilient ribs and locatable within the opening.
2. A cable clamp according to claim 1, wherein comprising two spring members.
3. A cable clamp according to claim 2, wherein the ribs of one spring member are io upwardly depending and the ribs of the other spring member are downwardly depending so that the ribs of one spring member are at least partially positionable within the ribs of the other spring member.
4. A cable clamp according to any of the preceding claims, wherein one spring IS member is positioned in the closure portion.
5. A cable clamp according to any of the preceding claims, wherein one spring member is positioned in the clamp body.
6. A cable clamp according to any of the preceding claims, wherein the closure portion is formed with grooves to receive the ribs.
7. A cable clamp according to any of the preceding claims, wherein the clamp body is formed with grooves to receive the ribs.
8. A cable clamp according to any of the preceding claims, wherein the ribs are connected as pairs to provide a substantially U-shaped profile.
9. A cable clamp according to any of the preceding claims, wherein each rib incorporates a curved region.
10. A cable clamp according to any of the preceding claims, wherein the ribs depend from a spine, the ribs positioned along two opposing sides of the spine.
11. A cable clamp according to claim 10, wherein the spring member further comprises a deflectable member depending from one end of the spine.
12. A cable clamp according to claim 10 or claim 11, wherein the spine is formed with at least one aperture.
13. A cable clamp according to any of claims 1 to 9, wherein the ribs are aligned along an axis and are connected to each other using first and second connecting members, each connecting member extending along the direction of the axis and connecting to edges of the ribs.
14. A cable clamp according to claim 13, wherein the connecting members incorporate at least one aperture to enable the spring member to be secured to the clamp body.
15. A cable clamp according to any of claims 2 to 9, wherein a first spring member is positioned in the closure portion and a second spring member is positioned in the clamp body, wherein the first spring member comprises ribs depending from a spine, the ribs positioned along two opposing sides of the spine and the second spring member comprises ribs connected as pairs and aligned along an axis, the pairs of ribs connected to each other using first and second connecting members, each connecting member extending along the direction of the axis and connecting to edges of the ribs.
16. A cable clamp according to claim 15, wherein the first spring member further comprises a deflectable member depending from one end of the spine.
17. A cable clamp according to any of the preceding claims, wherein the or each spring member further comprises protrusions depending from the ribs and configured to contact a region surrounding the or each spring member.