KR101606106B1 - Water resistant electrical cable gland - Google Patents

Abstract

There is provided a cable gland comprising an inner tubular body (4) having an outer tubular body (1) and an outer threaded portion (5) with a free end forming an inlet end (2) for the cable (3) The threaded portion interacts with the internal threaded portion 6 of the outer tubular body and the two bodies define an internal cavity for receiving the external clamping assembly and the external clamping assembly includes an external clamping cone 7 and an interaction clamping ring 8 , And when the inner tubular body is threaded into the outer tubular body, the outer clamping cone and the interaction clamping ring are actuated in an interaction relationship. An external thread on the inner tubular body is confined to the inner end region of the inner tubular body and a smooth outer cylindrical surface (9) with a diameter less than or equal to the minimum diameter of the thread end region extends from the thread end region To the nut portion (11). The inner surface of the outer tubular body has a circumferential groove (13) adjacent its end receiving the inner tubular body, which receives an endless seal (12) in the operative position, And interacts with the outer cylindrical surface of the body. The endless seal is positioned on the outer cylindrical surface of the inner tubular body adjacent the threaded end region of the inner tubular body or the circumferential groove in the outer tubular body prior to installation on the gland.

Description

{WATER RESISTANT ELECTRICAL CABLE GLAND}

The present invention relates to a general type of water resistant electric cable gland provided at the end of an electric cable in which the electric cable enters the electric junction box or other housing, Shape or other type of terminal.

More particularly, the invention relates to an electric cable gland for use in a cable of the kind having an armoring (generally referred to herein) located between an inner electrically insulating sheath and an outer electrically insulating sheath.

The term "exterior" in this specification is used in a broad sense. The term is therefore used to denote a mechanical protective layer generally having electrical conductivity (typically serving as a ground conductor) disposed between the innerview of the cable and the outer insulating sheath, and also of a substantial thickness of longitudinally rigid wire It includes an enclosure in the form of. The term has the broadest meaning and also does not have a substantially large tensile strength and also serves to provide a function of reinforcing the cable, a function of providing electromagnetic shielding, or an electrically conductive path typically used for grounding, It also includes more flexible wires.

These different types of sheathing have substantially different thicknesses and the present invention relates to cable glands that can accommodate these different thicknesses.

It is common to design a cable gland having an outer clamp in the form of a cone having an outer conical surface engaging the interior of the enclosure, said cone interacting with a clamping ring having a complementary conical inner surface, Tightly tightening the sheath between the surfaces. Due to the different constraints on the length and material content of the appropriate locking cone angle and cable gland, naturally clearly different sheath enclosures are not acceptable.

It is generally impractical and costly to provide different cable glands for each different thickness of sheath provided to the electrical cable, otherwise the cable glands will have similar size and characteristics.

One solution to this problem is described in British Patent 2,269,710, which describes a substantially conventional cone and clamping ring, wherein the cone is made substantially longer, or the clam ring is made shorter Or both, will simply accommodate other enclosure thicknesses that otherwise would have a substantially conventional configuration. This proposal is not particularly attractive when it is necessary to accommodate the substantial thickness difference of the enclosure, because the entire gland should be substantially longer, so that more material is consumed and thus the cost is increased.

British Patent No. 2,269, 711 discloses another proposal in which the clamping ring has two axially oriented conical surfaces opposite to each other and these conical surfaces are the right one of the two possible axially opposite positions in the gland Position to be combined with cable sheaths of different thicknesses. It is difficult to install these glands because it is difficult to find the right direction on the outer surface of the clamping ring. Applicants believe this configuration is impractical and may even be dangerous if the clamping ring is not installed in the right direction.

British Patent No. 2,296,998 discloses another proposal in which the outer conical surface of the cone is stepped to provide two different conical surfaces with the same cone angle, Thereby selectively coupling with the same clamping ring. Inevitably, the working length of the clamping surface is limited, and for proper installation of such cable glands, the free end of the enclosure needs to be trimmed somewhat precisely, which is extremely difficult to achieve and control in the open air where normal hand tools are not available.

According to the configuration described in International Patent Publication No. WO 01/93396, the clamping cone and clamping ring have two different vertex angles, thus providing a peripheral clamping surface for a thinner sheathing, and also for a thicker sheathing, Angles are provided. Applicant thinks this configuration is better.

In the latter configuration and some other solutions mentioned, the relative axial movement of the outer body relative to the inner body must be greater. The electrons generally interact directly with the clamping ring and the clamping cone is urged by the inner body toward the clamping ring, the inner body having threads interacting with the threads on the inner surface of the outer body.

In the case of water resistant cable glands (often referred to as "deluge resistant glands"), one type of seal to prevent water from entering the cable sheath clamp is the outer surface of the inner cable gland body An O-ring seal held in a groove that seals against a smooth cylindrical surface on the inner surface of the outer body of the gland. Of course, the other axial position of the inner body with respect to the outer body, depending on the different thickness of the sheath, should be long enough to accommodate both axial end positions with a smooth inner surface interacting with the O-ring .

The outer cable gland body is typically made by turning a metal extrudate, typically of a suitable grade of brass, stainless steel or aluminum, from a suitable lathe. These extrusions are expensive and therefore it is desirable that the length of the extruded article used for each cable gland is limited to only the required length.

It is an object of the present invention to provide a cable gland of the general type described above which uses an O-ring or other endless seal between the outer cable gland body and the inner cable gland body, And the length of the outer cable gland body is shorter than that of the case where the O-ring seal is maintained.

According to the present invention there is provided a cable comprising an inner tubular body having an outer tubular body and an outer threaded portion having a free end defining an inlet end for the cable, the outer threading portion interacting with the inner threaded portion of the outer tubular body, The body defines an inner cavity for receiving the outer clamp assembly, wherein the outer clamp assembly includes an outer clamping cone and an interacting clamping ring, wherein when the inner tubular body is threaded into the outer tubular body, the outer clamping cone and the interaction clamping ring The ring is provided with a cable gland that is operatively pressurized in an interaction relationship wherein the external thread on the inner tubular body is confined to the inner end region of the inner tubular body and has a minimum diameter Wherein a smooth outer cylindrical surface having a diameter is provided in said threaded end region Wherein the inner surface of the outer tubular body has a circumferential groove adjacent its end receiving the inner tubular body, the groove receiving an endless seal in the operative position , The endless seal interacting with the outer cylindrical surface of the inner tubular body and the endless seal being located in the circumferential groove in the outer tubular body prior to installation in the gland or adjacent the thread end region of the inner tubular body And is located on the outer cylindrical surface of the inner tubular body.

In another aspect of the present invention, the endless seal is an elastomeric O-ring seal, and the end of the outer tubular body that houses the inner tubular body has an introduction tapered portion, An O-ring located on the outer cylindrical surface of the inner tubular body immediately adjacent to the outer tubular body is automatically pressed and placed into the outer tubular body to snap into the operative position in the circumferential groove, Which groove partially receives the seal in preparation before the O-ring seal is introduced into its operative position, and the internal threads of the outer tubular body are formed in the circumferential groove , And the outer clamping cone and the interacting clamping ring have their different It is to sin the exterior of different thicknesses in the direction of the relative position.

In a preferred configuration, the outer clamping cone and the clamping ring have a first interacting conical clamping surface with a relatively small cone angle that is substantially conventional, as described in International Patent Publication No. WO 01/93396, At the large diameter end of each first conical clamping surface of the ring, it has a second interacting clamping surface that is widened outwardly from the first conical surface.

The second interaction clamping surfaces are thus adapted to clamp a relatively small thickness of sheath between them and the first interaction clamping surface is intended to clamp a relatively large thickness of sheath between them. The cone angle of the first interacting conical clamping surface is between 15 and 25 degrees and is preferably about 20 degrees so that the first clamping surface has an angle of between 7.5 and 12.5 degrees with the axis of the cable gland, Respectively. The second interacting clamping surfaces have in each case a cone angle of 60 to 90 degrees, preferably a cone angle of about 70 degrees, so that the second clamping surface is about 30 to about 45 degrees with the axis of the cable gland, 35 degrees.

The cable gland is preferably in a two-part configuration, wherein the clamping cone is held against the inner tubular body and the clamping ring is held at least temporarily in the outer tubular body.

The cable gland preferably has an inner compression seals and an outer compression seals that are sealed on the inner and outer sheaths of the cable.

In order that the present invention may be more fully understood, one embodiment thereof will be described with reference to the accompanying drawings.

1 is an elevational view of a cable gland according to the invention, the upper half of which is shown in cross-section.
Fig. 2 is an enlarged cross-sectional view showing the relationship between the outer tubular body and the inner tubular body, with the cone and the clamping ring separated by a thick sheath wire clamped between them.
Figure 3 is a view similar to that of Figure 2 showing an outer tubular body and an inner tubular body (only half of which is shown in cross-sectional view), the cone and the clamping ring being separated by a thin sheath wire clamped between them.
Figure 4 shows these inner and outer tubular bodies in a similar view, just before the inner tubular body is installed on the outer tubular body.
Figure 5 shows in a similar view the position of a prior art O-ring located in a groove in the outer surface of the inner tubular body and also clearly shows the reduction in the length of the outer body.

In the embodiment of the invention shown in Figures 1-4, the cable gland comprises an outer tubular body 1 and an outer threaded portion 5 having a free end 2 forming an inlet end for the cable 3 The outer threaded portion interacting with the inner threaded portion 6 of the outer tubular body.

In the illustrated condition, the two bodies define an internal cavity for receiving an external clamp assembly including an external clamping cone 7, and when the internal tubular body is threaded into the external tubular body, ) In an interaction relationship.

As provided by the present invention, the external threads in the inner tubular body are short in length and confined to the inner end region of the inner tubular body. A smooth outer cylindrical surface 9 with a diameter somewhat smaller than the minimum diameter of the threaded end region extends from the threaded end region to the nut portion 11 outside the outer tubular body.

The inner surface of the outer tubular body has an endless O-ring seal (12) received in a circumferential groove (13) adjacent to an end thereof receiving the inner tubular body. This O-ring seal engages the outer cylindrical surface of the inner tubular body and completely seals the inflow passageway leading from the exterior to the cavity and enclosure wire that receives the outer clamp.

In order to facilitate assembly of the cable gland, the end of the outer tubular body, which receives the inner tubular body, has an introduction tapered portion 14 which, as seen in FIG. 4, An O-ring, which fits snugly on the outer cylindrical surface of the tubular body, is automatically compressed and placed into the outer tubular member to snap into engagement with the operative position in the circumferential groove. To assist in this process, the inner tubular body is provided with a shallow groove 21 immediately adjacent to the external threaded portion 5, so that the O-ring is partially located in its shallow groove. Such grooves typically have a width less than the cross-sectional diameter of the O-ring, preferably about 1/2 of the cross-sectional diameter of the O-ring. This is shown in FIG. The internal threads in the outer tubular body may extend beyond the circumferential groove for convenience of manufacture.

As described above, the outer clamping cone and clamping ring have a first interacting conical clamping surface 15 with a relatively small cone angle that is substantially conventional, as described in International Patent Publication No. WO 01/93396, At the large-diameter end of the first conical clamping surface of each of the cone and clamping ring, it has a second interacting clamping surface 16 that is widened outwardly from the first conical surface.

Thus, the second interaction clamping surfaces are adapted to clamp a relatively small thickness enclosure between them, as shown in Fig. 3, and the first interaction clamping surfaces are relatively small It is intended to fasten a large thickness of sheathing. The cone angle of these two surfaces is preferably the preferred cone angle.

In this embodiment of the present invention, the cable gland has a two-part configuration wherein the clamping cone is held against the inner tubular body and the clamping ring is held at least temporarily held on the outer tubular body.

The cable gland has an inner compression seal (17) and an outer compression seal (18) sealed on the inner and outer sheaths (19, 20) of the cable.

By constituting the cable gland as described above, the length of the extruded material constituting the outer tubular body can be remarkably reduced. This can be seen clearly in Figure 5 where an O-ring A disposed in the groove B of the inner tubular body C and interacting with the smooth inner surface D of the outer tubular body E Lt; RTI ID = 0.0 > gland < / RTI > In the practice of the present invention, the outer tubular body may end up in the conventional state as indicated by the dotted line (F).

Many modifications may be made to the embodiments of the invention described above without departing from the scope of the invention.

Claims (10)

An outer tubular body having a free end forming an inlet end for the cable and an inner tubular body having an outer threaded portion, the outer threaded portion interacting with the inner threaded portion of the outer tubular body, the inner tubular body and the outer The tubular body defines an inner cavity for receiving the outer clamp assembly, wherein the outer clamp assembly includes an outer clamping cone and an interaction clamping ring, wherein when the inner tubular body is threaded into the outer tubular body, The clamping ring is a cable gland that is actuated in an interacting relationship,
Wherein an external thread on the inner tubular body is confined to an inner end region of the inner tubular body and wherein a smooth outer cylindrical surface having a diameter less than or equal to the minimum diameter of the threaded end region extends from the threaded end region to the outer tubular body exterior The inner surface of the outer tubular body having a circumferential groove adjacent its end receiving the inner tubular body which receives an endless seal in the operative position, Wherein the endless seal is located in the circumferential groove in the outer tubular body prior to installation in the gland or adjacent the outer end of the inner tubular body adjacent the threaded end region of the inner tubular body, Wherein the cable gland is located on a cylindrical surface. The method according to claim 1,
Wherein the endless seal is an elastomeric O-ring seal. 3. The method of claim 2,
The end of the outer tubular body that houses the inner tubular body has an introducing tapered portion that is adjacent to a threaded end region of the inner tubular body when the inner tubular body is threaded into the outer tubular body, Wherein the O-ring positioned on the outer cylindrical surface is automatically crimped to roll into the outer tubular body and snap into engagement with the operative position within the circumferential groove. The method of claim 3,
The inner tubular body has a shallow circumferential groove immediately adjacent its threaded end region that partially receives the seal in preparation for the O-ring seal to be introduced into its operative position. 5. The method according to any one of claims 1 to 4,
Wherein the inner thread of the outer tubular body extends beyond the circumferential groove. 5. The method according to any one of claims 1 to 4,
Wherein the outer clamping cone and the interacting clamping ring are adapted to clamp an outer sheath of different thickness at their different axial relative positions. The method according to claim 6,
The outer clamping cone and the clamping ring each having a first interacting conical clamping surface with a common cone angle and also at a large diameter end of the first cone clamping surface of each of the cone and the clamping ring, A cable gland having a second, interacting clamping surface. 8. The method of claim 7,
Wherein the first interacting conical clamping surface has a cone angle of 15 to 25 degrees such that the first clamping surface forms an angle of 7.5 to 12.5 degrees with the axis of the cable gland, Wherein the second clamping surface has an angle of 30 to 45 degrees with the axis of the cable gland. 5. The method according to any one of claims 1 to 4,
Wherein the cable gland is in a two-part configuration, the clamping cone being held against the inner tubular body and the clamping ring held at least temporarily in the outer tubular body. 5. The method according to any one of claims 1 to 4,
The cable gland is an inner sheath of the cable and a cable gland having an inner compression seal and an outer compression seal that are sealed on the outer sheath.

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