WO2021243682A1

WO2021243682A1 - Diameter adapter accessory for cable strain relief

Info

Publication number: WO2021243682A1
Application number: PCT/CN2020/094572
Authority: WO
Inventors: Tjaco Middel
Original assignee: Tridonic Gmbh & Co Kg
Priority date: 2020-06-05
Filing date: 2020-06-05
Publication date: 2021-12-09
Also published as: EP4140003A1; CN115699487A; EP4140003A4

Abstract

A single cable strain relief is difficult to securely fix multiple cables of different diameters. A diameter adapter accessory removably installable in the cable strain relief assists a first cable to securely fix to the cable strain relief by inflating the first cable's thickness. The accessory has a body formed with an adapter channel. The adapter channel has a first cross-sectional width adjustable such that when the first cable is inserted through the adapter channel, the first cable is clamped and fixed to the body via adjusting the first cross-sectional width. As the body encloses the first cable, the body has a second cross-sectional width greater than the first cross-sectional width, enabling a second cable thicker than the first cable to be securely clamped by the same strain-relief channel such that both the first and second cables having different diameters are securely fixed to the cable strain relief.

Description

Diameter Adapter Accessory for Cable Strain Relief

TECHNICAL FIELD

The present disclosure relates to an accessary used with a cable strain relief for assisting an individual cable to securely fix to the cable strain relief so as to enable plural cables to securely fix to the cable strain relief even if the cables have different diameters.

BACKGROUND

A cable strain relief, also known as a cord grip or a cable gland, is a mechanical device for attaching and securing an end of an electrical cable to the equipment. A major purpose of using the cable strain relief is to provide strain relief to the electrical cable such that when the electrical cable is pulled abruptly, or is subject to a constant pulling force, the electrical cable is made more difficult to be detached from the equipment. Unintended detachment of the electrical cable from the equipment is undesirable or even dangerous. For example, if the electrical cable used for supplying power to the equipment, such as a lighting device driver, is suddenly detached from the equipment, it may result in damage to the equipment, or exposed terminals of the electrical cable may lead to safety hazard to nearby personnel. The cable strain relief is indispensable in increasing equipment reliability and safety.

In practical situations, it is usually required to secure multiple cables to a group of nearby terminals of an equipment. To reduce cost, one may use a single cable strain relief to secure all the cables together. All the cables, however, can be securely and reliably fixed to the cable strain relief only if all the cables are of same size. Providing strain relief to cables of different diameters is also required in practical situations. FIG. 1 depicts two conventional solutions of providing strain relief to two cables of different diameters as an example situation for illustration, where cross-sectional views of respective cable strain reliefs are depicted. In a first solution 110, a single cable strain relief 111 having a channel 112 is used to securely lock a first cable 181 and a second cable 182 of different size. The first cable 181 is smaller than the second cable 182 in diameter. Although the second cable 182 is securely fixed to the cable strain relief 111 by adjusting a cross-sectional width 113 of the channel 112, the width 113 is too large to securely fix the first cable 181. The ability of the first cable 181 to resist against an unwanted pulling force is greatly reduced or even vanishes. In a second solution 120, two separate cable strain reliefs, namely, first and second

cable strain reliefs

121, 122, are used to individually secure the first and

second cables

181, 182, respectively. Cross-sectional widths 123, 124 of the first and second

cable strain reliefs

121, 122 can be independently adjusted to respectively fit to diameters of the first and

second cables

181, 182 so that the two

cables

181, 182 can be securely locked. However, the second solution 120 has several disadvantages over the first solution 110. One disadvantage is that the total cost of the two

cable strain reliefs

121, 122 is higher than the cost of the single cable strain relief 111. Another disadvantage is on the aesthetic aspect. The first and second

cable strain reliefs

121, 122 have uneven height, creating an aesthetic impression that is not nice-looking. Although the aesthetic problem may be solved with an additional cover, it results in an additional cost. A further disadvantage occurs in designing an equipment. A designer may be uncertain whether cables to be connected to the equipment are of same or different size. It sometimes forces the designer to install multiple cable strain reliefs in the equipment. Extra cost is incurred but the multiple cable strain reliefs are often not needed during actual use of the equipment.

There is a need in the art for a technique of using a single cable strain relief to fix a plurality of cables of different size while securely locking all the cables to the cable strain relief.

SUMMARY

An aspect of the present disclosure is to provide a diameter adapter accessory for assisting a first cable to securely fix to a cable strain relief. The cable strain relief has a strain-relief channel used for concurrently clamping at least the first cable and a second cable. The second cable is thicker than the first cable.

The accessory comprises a body formed with an adapter channel such that the first cable is insertable into the adapter channel. A cross-section of the adapter channel has a first cross-sectional width adjustable such that when the first cable is inserted through the adapter channel, the cross-section is widened or narrowed to clamp the first cable via adjusting the first cross-sectional width. The first cable is thereby fixed to the body. The body is configured to have a second cross-sectional width greater than the first cross-section width under a condition that the first cable is clamped in the adapter channel and the body is positioned in and clamped by the strain-relief channel, where the second cross-sectional width is determined as a minimum cross-sectional width of the body under the aforesaid condition. Thereby, both the accessory and the second cable are enabled to be concurrently and securely clamped by the strain-relief channel such that both the first and second cables are securely fixed to the cable strain relief even though the two cables have different diameters.

In certain embodiments, the adapter channel is circumferentially enclosed by the body to thereby make the second cross-sectional width greater than the first cross-sectional width.

In certain embodiments, the accessory further comprises a clamping fixture for clamping the first cable. The clamping fixture is attached to the body and configured to controllably narrow or widen the cross-section of the adapter channel. The first cross-sectional width is thereby adjusted.

The clamping fixture may comprise a first edge having an adjustable depth of protruding into the adapter channel so as to adjust the first cross-sectional width and to clamp the first cable. Preferably, the first edge is grooved or corrugated for enhancing friction with the first cable. Optionally, the clamping fixture further comprises an adjustable screw for adjusting the protruding depth of the first edge.

The clamping fixture may further comprise a second edge attached to the body and opposite to the first edge. The first and second edges are collectively used to controllably narrow or widen the cross-section of the adapter channel. Preferably, the second edge is grooved or corrugated for enhancing friction with the first cable.

In certain embodiments, the body and the clamping fixture are substantially rigid. The body and the clamping fixture may be integrally formed with a same material.

Optionally, the accessory further comprises an exterior flange surrounding the body for assisting the accessory to position in the strain-relief channel. The exterior flange and the body may be integrally formed with a same material.

In certain embodiments, the body is substantially rigid such that the second cross-sectional width is a fixed one. The body may be substantially made of plastic or metal.

In certain embodiments, the body is deformable, allowing the first cable to be clamped by pressing the body via adjusting the strain-relief channel. The body may be substantially made of a polymer. The polymer may be an elastomer or a resin.

In certain embodiments, the body is substantially made of a composite material comprising a polymer matrix with filler particles or fibers.

Other aspects of the present disclosure are disclosed as illustrated by the embodiments hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

The appended drawings, where like reference numerals refer to identical or functionally similar elements, contain figures of certain embodiments to further illustrate and clarify various aspects, advantages and features of an output load identification method and an apparatus incorporating such method as disclosed herein. It will be appreciated that these drawings and graphs depict only certain embodiments of the invention and are not intended to limit its scope. The diameter adapter accessory as disclosed herein will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

FIG. 1 depicts two conventional solutions of providing strain relief to two cables of different size, where cross-sectional views of cable strain reliefs in locking the two cables are depicted;

FIG. 2 depicts cross-sectional and side views of a cable strain relief fixing a first cable and a second cable that is thicker than the first cable, where a diameter adapter accessory, in accordance with an exemplary embodiment of the present disclosure, clamps the first cable and is in turn clamped by the cable strain relief; and

FIG. 3 depicts various views of the accessory for illustrating a structure of the accessory, where the views include a front view, a top view, a side view, and a cross-sectional view of the side view.

Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been depicted to scale.

DETAILED DESCRIPTION

The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the present disclosure or the following detailed description.

To securely lock plural cables of different size with a single cable strain relief, one may first identify the thickest cable among all the cables and then artificially inflate remaining cables each to have a thickness close to that of the thickest cable. After inflation, all the cables are substantially close in size, enabling the single cable strain relief to securely lock the cables.

Disclosed herein is a diameter adapter accessory removably installable in a cable strain relief for assisting a first cable to securely fix to the cable strain relief by the aforementioned approach of inflating a thickness of the first cable. The disclosed accessory gives an advantage that when a second cable thicker than the first cable is concurrently clamped by the cable strain relief, both the first and second cables can be securely fixed to the cable strain relief even though the two cables have different diameters.

The disclosed diameter adapter accessory is exemplarily illustrated with the aid of FIGS. 2 and 3. FIG. 2 depicts cross-sectional and side views of a cable strain relief 211 fixing a first cable 281 and a second cable 282 that is thicker than the first cable 281, where the first cable 281 is clamped by an exemplary diameter adapter accessory 300 and the accessory 300 is in turn clamped by the cable strain relief 211. FIG. 3 depicts various views of the accessory 300 for illustrating a structure of the accessory 300, where the views include a front view, a top view, a side view, and a cross-sectional view of the side view.

The cable strain relief 211 is a conventional one, and has a strain-relief channel 212 for allowing the first and

second cables

281, 282 to be inserted into the cable strain relief 211. The strain-relief channel 212 is configured to concurrently clamp at least the first cable 281 and the second cable 282.

The accessory 300 comprises a body 310 formed with an adapter channel 320. The adapter channel 320 is open at both ends 321, 322 such that the first cable 281 is insertable into the adapter channel 320. The adapter channel 320 is an interior channel of the body 310. An exterior surface 311 and an interior surface 312 both of the body 310 are identifiable. As the adapter channel 320 is an interior channel, the adapter channel 320 is in contact with the interior surface 312 rather than the exterior surface 311.

The adapter channel 320 has a cross-section 323. The cross-section 323 is obtained as an intersection of a plane and the adapter channel 320, where the plane is perpendicular to a major axis 305 of the adapter channel 320. The cross-section 323 is selected from different possible choices of cross-section in the adapter channel 320 such that the cross-section 323 as selected has a first cross-sectional width 325 adjustable in length. In particular, the first cross-sectional width 325 is adjustable such that when the first cable 281 is inserted through the adapter channel 320, the cross-section 323 is widened or narrowed to clamp the first cable 281 via adjusting the first cross-sectional width 325. The first cable 281 is thereby fixed to the body 310. For instance, as shown in FIG. 3, a pair of mutually-

opposite edges

341, 342, installed on the body 310 and with a mechanism to adjust a separation between the two

edges

341, 342, is used to contact and press the first cable 281 such that a pair of opposite forces created by the two

edges

341, 342 is acted on the first cable 281 and immobilizes the first cable 281. The aforesaid separation is the first cross-sectional width 325. Other methods of adjusting the first cross-sectional width 325 will be detailed later.

The body 310 is configured to have a second cross-sectional width 315 greater than the first cross-sectional width 325 under a condition that (1) the first cable 281 is clamped in the adapter channel 320 and (2) the body 310 is positioned in and clamped by the strain-relief channel 212. The second cross-sectional width 315 is determined as a minimum cross-sectional width of the body 310 under the aforesaid condition. Note that the second cross-sectional width 315 is measured between two points on the exterior surface 311 of the body 310. Since the second cross-sectional width 315 is greater than the first cross-sectional width 325, it follows that the first cable 381 is effectively inflated by coating with the accessory 300. By adjusting the second cross-sectional width 315 to be close to a diameter of the second cable 282, the size of the strain-relief channel 212 can be adjusted to concurrently and securely clamp the second cable 282, which is thicker than the first cable 281, and the accessary 300. As a result, both the first and

second cables

281, 282 are securely fixed to the cable strain relief 211 although the two

cables

281, 282 have different diameters.

The body 310 may be realized to be substantially rigid or deformable. If the body 310 is substantially rigid, the second cross-sectional width 315 is a fixed one and has a fixed value. A substantially-rigid body may be formed with a rigid material such as plastic, aluminum, steel, brass or other metal. If the body 310 is deformable, the first cable 281 can be fixed to the body 310 by pressing the body 310 towards the first cable 281 via adjusting the strain-relief channel 212 (viz., narrowing or widening the strain-relief channel 212) . The pressing of the body 310 towards the first cable 281 effectively causes the first cross-sectional width 325 to be adjusted. A soft material, such as a polymer (e.g., an elastomer, a resin, etc. ) , may be used to form a deformable body. A composite material comprising a polymer matrix with filler particles or fibers may also be used to form a substantially-rigid body or a deformable body depending on the selected filler particles/fibers. For example, a polyamide matrix filled with glass fibers may be used to form a substantially-rigid body.

In certain embodiments, the adapter channel 320 is circumferentially enclosed by the body 310. It follows that the adapter channel 320 is closed except the two ends 321, 322. Hence, the body 310 is shaped to have a tubular form. Since the exterior surface 311 and the interior surface 312 are separated by some materials that form the body, there is a non-zero width between the two

surfaces

311, 312. As the interior surface 312 surrounds the adapter channel 320, the condition that the second cross-sectional width 315 is greater than the first cross-sectional width 325 is automatically satisfied. This condition is satisfied regardless of whether the body 310 is rigid or deformable. If the body 310 is rigid, forming the body 310 in a tubular form (which resembles an O-shape in cross-section) is preferable over forming the body 310 with a C-shape in cross-section or with a cross-sectional shape like an arc in that the O-shape cross-section is mechanically more rigid and more difficult to be bent. Nevertheless, it is not intended that the disclosed accessory has a body limited only to a tubular shape; other shapes such as the C-shape may be used to form the body.

In certain embodiments, the accessory 300 further comprises a clamping fixture 340 for clamping the first cable 281. The clamping fixture 340 is attached to the body 310 and configured to controllably narrow or widen the cross-section 323 of the strain-relief channel 212 for adjusting the first cross-sectional width 325. The clamping fixture 340 is essential for effectively clamping the first cable 281 if the body 310 is substantially rigid. If the body 310 is deformable, the clamping fixture 340 is optional since the first cable 281 may be fixed to the body 310 by pressing the body 310.

The clamping fixture 340 comprises a first edge 341 located on the interior surface 312 of the body 310. The first edge 341 is used to contact and press on the first cable 281 to immobilize the first cable 281 in the adapter channel 320.

In certain embodiments, the first edge 341 has a depth 345 of protruding into the adapter channel 320 (referred hereinafter as a protruding depth 345) to be adjustable so as to adjust the first cross-sectional width 325 and to clamp the first cable 281. To adjust the protruding depth 345, a mechanism is installed in the clamping fixture 340 to drive the first edge 341 to move into or retract from the adapter channel 320. In some implementations, the clamping fixture 340 further comprises an adjustable screw 343 for adjusting the protruding depth 345 of the first edge 341. In one convenient implementation, the tip of the adjustable screw 343 may be used to form the first edge 341.

If the body 310 is deformable, the clamping fixture 340 may be simplified by having the protruding depth 345 of the first edge 341 to be fixed and non-adjustable. The narrowing or widening of the cross-section 323 of the adapter channel 320 to adjust the first cross-sectional width 325 is achieved by pressing the body 310 towards the first cable 281.

In certain embodiments, the first edge 341 is also configured to exert a frictional force on the first cable 281 for resisting the first cable 281 from rotation inside the adapter channel 320. Preferably, the first edge 341 is grooved or corrugated for enhancing the frictional force with the first cable 281.

The clamping fixture 340 may further comprise a second edge 342 located on the interior surface 312 and opposite to the first edge 341. The first and

second edges

341, 342 are collectively used to controllably narrow or widen the cross-section 323 of the adapter channel 320. Preferably, the second edge 342 is grooved or corrugated for enhancing a frictional force with the first cable 281 for resisting the first cable 281 from rotation inside the adapter channel 320.

Usually, the clamping fixture 340 is designed and manufactured to be substantially rigid since a mechanism is required to be installed therein for adjusting the protruding depth 345. It is possible that both the body 310 and the clamping fixture 340 are substantially rigid. In this case, the body 310 and the clamping fixture 340 may be integrally formed with a same material.

If the body 310 is deformable, the accessory 300 may be designed to have the first and

second edges

341, 342 attached and integrated to the body 310 without installing a mechanism to adjust the protruding depth 345 of the first edge 341. Similarly, it is possible that both the body 310 and the clamping fixture 340 are deformable. The body 310 and the clamping fixture 340 may be integrally formed with a same material.

Optionally, the accessory 300 further comprises an exterior flange 370 surrounding the body 310 for assisting the accessory 300 to position in the strain-relief channel 212. See FIG. 2. During installation of the accessory 300 into the cable strain relief 211, the exterior flange 370 enables a technician to easily park the accessory 300 in a preferred pre-selected position in the strain-relief channel 212. The exterior flange 370 may be realized in a form of a complete annular ring or a broken one. The exterior flange 370 and the body 310 may be integrally formed with a same material.

Although FIG. 2 depicts a specific case that the cable strain relief 211 is used to securely lock only two cables, viz., the first and

second cables

281, 282, those skilled in the art will appreciate that the application of the accessory 300 is easily extensible in case more than two cables of different size are to be fixed to a certain single-channel cable strain relief. For example, plural diameter adapter accessories as disclosed herein are respectively used to clamp the cables other from the thickest one such that the thickest cable and all remaining cables coated with respective accessories have substantially similar diameters.

A list of advantages offered by the disclosed accessory is provided as follows. One application of the accessory is in light emitting diode (LED) drivers. Particular advantages to designing LED drivers are also elaborated.

· The disclosed accessory allows a cable strain relief to apply an optimized force to hold multiple cables of different diameters.

· A limitless number of cables can be hold by the cable strain relief via diameter adaption by using one or more disclosed accessories, as long as the cables can fit a strain-relief channel of the cable strain relief.

· The cable strain relief that holds multiple cables of different diameters is still aesthetically nice looking because only one cable strain relief is visible at the outside.

· The disclosed accessory is simple in structure and is hence a low-cost solution to assist a cable strain relief to hold a cable in the presence of multiple cables of different diameters, making the use of a single cable strain relief to hold multiple cables to be a very cost-effective solution.

· If the cable strain relief is used in a LED driver housing, the overall design of the cable strain relief can be optimized at low cost for any cable by using one or more disclosed accessories for diameter adaption of cables of different size.

· If a standard cable strain relief has been used for a design of a LED driver, and if the LED driver is newly required to connect to cables of different size, the original design may be kept without any customization needed by using the disclosed accessory.

· At the design stage of a LED driver, a designer may not be certain whether cables to be connected to the LED driver are of same or different size. By advising an actual user of the LED driver to employ one or more accessories in case the cables have non-identical size, the designer may design a housing of the LED driver with a single cable strain relief instead of multiple ones for cost saving.

In the present disclosure, the use of the terms “a” and “an” and “the” and “at least one” and similar referents in the context of describing disclosed systems, apparatuses, devices, methods and processes (especially in the context of the accompanied claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B” ) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B) , unless otherwise indicated herein or clearly contradicted by context. The terms “comprising, ” “having, ” “including, ” and “containing” are to be construed as open-ended terms (i.e. meaning “including, but not limited to, ” ) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as” ) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

While exemplary embodiments have been presented in the foregoing detailed description of the invention, it should be appreciated that a vast number of variations exist. It should further be appreciated that the exemplary embodiments are only examples, and are not intended to limit the scope, applicability, operation, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention, it being understood that various changes may be made in the function and arrangement of steps and method of operation described in the exemplary embodiment without departing from the scope of the invention as set forth in the appended claims.

Claims

A diameter adapter accessory for assisting a first cable to securely fix to a cable strain relief, the cable strain relief having a strain-relief channel used for concurrently clamping at least the first cable and a second cable, the second cable being thicker than the first cable, the accessory comprising:

a body formed with an adapter channel such that the first cable in insertable into the adapter channel, wherein:

a cross-section of the adapter channel has a first cross-sectional width adjustable such that when the first cable is inserted through the adapter channel, the cross-section is widened or narrowed to clamp the first cable via adjusting the first cross-sectional width, whereby the first cable is fixed to the body; and

the body is configured to have a second cross-sectional width greater than the first cross-section width under a condition that the first cable is clamped in the adapter channel and the body is positioned in and clamped by the strain-relief channel, the second cross-sectional width being determined as a minimum cross-sectional width of the body under said condition, thereby enabling both the accessory and the second cable to be concurrently and securely clamped by the strain-relief channel such that both the first and second cables are securely fixed to the cable strain relief even though the two cables have different diameters.
The accessory of claim 1, wherein the adapter channel is circumferentially enclosed by the body to thereby make the second cross-sectional width greater than the first cross-sectional width.
The accessory of claim 1 further comprising:

a clamping fixture for clamping the first cable, wherein the clamping fixture is attached to the body and configured to controllably narrow or widen the cross- section of the adapter channel, whereby the first cross-sectional width is adjusted.
The accessory of claim 3, wherein the clamping fixture comprises a first edge having an adjustable depth of protruding into the adapter channel so as to adjust the first cross-sectional width and to clamp the first cable.
The accessory of claim 4, wherein the first edge is grooved or corrugated for enhancing friction with the first cable.
The accessory of claim 4, wherein the clamping fixture further comprises an adjustable screw for adjusting the protruding depth of the first edge.
The accessory of claim 4, wherein the clamping fixture further comprises a second edge attached to the body and opposite to the first edge, the first and second edges being collectively used to controllably narrow or widen the cross-section of the adapter channel.
The accessory of claim 7, wherein the second edge is grooved or corrugated for enhancing friction with the first cable.
The accessory of claim 3, wherein the body and the clamping fixture are substantially rigid.
The accessary of claim 9, wherein the body and the clamping fixture are integrally formed with a same material.
The accessory of claim 1 further comprising:

an exterior flange surrounding the body for assisting the accessory to position in the strain-relief channel.
The accessory of claim 11, wherein the exterior flange and the body are integrally formed with a same material.
The accessory of any of claims 1-12, wherein the body is substantially rigid such that the second cross-sectional width is a fixed one.
The accessory of claim 13, wherein the body is substantially made of plastic.
The accessory of claim 13, wherein the body is substantially made of metal.
The accessory of any of claims 1-12, wherein the body is deformable, allowing the first cable to be clamped by pressing the body via adjusting the strain-relief channel.
The accessory of claim 16, wherein the body is substantially made of a polymer.
The accessory of claim 17, wherein the polymer is an elastomer or a resin.
The accessory of any of claims 1-12, wherein the body is substantially made of a composite material comprising a polymer matrix with filler particles or fibers.