CA1137186A - Electrical connection using a heat-recoverable device and mechanical retaining means - Google Patents
Electrical connection using a heat-recoverable device and mechanical retaining meansInfo
- Publication number
- CA1137186A CA1137186A CA000318515A CA318515A CA1137186A CA 1137186 A CA1137186 A CA 1137186A CA 000318515 A CA000318515 A CA 000318515A CA 318515 A CA318515 A CA 318515A CA 1137186 A CA1137186 A CA 1137186A
- Authority
- CA
- Canada
- Prior art keywords
- retaining means
- heat
- sheet material
- recoverable
- substrate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R4/00—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation
- H01R4/70—Insulation of connections
- H01R4/72—Insulation of connections using a heat shrinking insulating sleeve
- H01R4/726—Making a non-soldered electrical connection simultaneously with the heat shrinking
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R4/00—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation
- H01R4/58—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation characterised by the form or material of the contacting members
- H01R4/60—Connections between or with tubular conductors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R4/00—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation
- H01R4/58—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation characterised by the form or material of the contacting members
- H01R4/64—Connections between or with conductive parts having primarily a non-electric function, e.g. frame, casing, rail
Landscapes
- Cable Accessories (AREA)
- Insulating Bodies (AREA)
- Multi-Conductor Connections (AREA)
Abstract
ABSTRACT
An electrical connection is made to a substrate such as the conductive sheath of an electric cable using a heat-recoverable wrap-around device. The mechanical retaining means of the device forms part of the electrical connection or is itself provided with means for doing so. The retaining means advantageously lies flush with the substrate after recovery and in preferred embodiments is a buckle in which the heat-recoverable sheet material is held by frictional forces and which can be insulated by said sheet material after recovery.
An electrical connection is made to a substrate such as the conductive sheath of an electric cable using a heat-recoverable wrap-around device. The mechanical retaining means of the device forms part of the electrical connection or is itself provided with means for doing so. The retaining means advantageously lies flush with the substrate after recovery and in preferred embodiments is a buckle in which the heat-recoverable sheet material is held by frictional forces and which can be insulated by said sheet material after recovery.
Description
11~7~8~
T.h~is invention relates to heat-recoverable articles and, more especiaily, to their use in forming andinsulating electrical connections.
The formation and insulation cr electrical connections to substrates has, until recently, involved a series of operations. First, the substrate is prepared, next the electrical connection is made, for example mechanically and/
or by soldering, and finally the connection is insulated.
Over the last decade this process has, to some extent, been simplified by so-called heat-recoverable articles, especially heat-shrinkable articles, which are now widely used in many areas where insulation, sealing and encapsulation are required. Usually these articles recover, on heating, to-wards an original shape from which they have previously been deformed, but the term "heat-recoverable" as used herein also includes an article whih, on heating, adopts a new configura-tion, even if it has not been previously deformed.
In their most common form, such articles comprise a heat-shrinkable sleeve made from a polymeric material exhibiting the property of elastic or plastic memory as described, for example, in U.S. Patents 2,027,962, 3,086,2~2 and 3,597,372. As is made clear in, for example, U.S. Patent 2,027-,962, the original di-mensionally heat-stable form may be a transient form in a con-tinuous process in which, for example, an extruded tube is expanded, whilst hot, to a dimensionally heat-unstable form but, ; in other applications, a preformed dimensionally heat stable article is deformed to a dimensionally heat-unstable form in a separate stage.
T.h~is invention relates to heat-recoverable articles and, more especiaily, to their use in forming andinsulating electrical connections.
The formation and insulation cr electrical connections to substrates has, until recently, involved a series of operations. First, the substrate is prepared, next the electrical connection is made, for example mechanically and/
or by soldering, and finally the connection is insulated.
Over the last decade this process has, to some extent, been simplified by so-called heat-recoverable articles, especially heat-shrinkable articles, which are now widely used in many areas where insulation, sealing and encapsulation are required. Usually these articles recover, on heating, to-wards an original shape from which they have previously been deformed, but the term "heat-recoverable" as used herein also includes an article whih, on heating, adopts a new configura-tion, even if it has not been previously deformed.
In their most common form, such articles comprise a heat-shrinkable sleeve made from a polymeric material exhibiting the property of elastic or plastic memory as described, for example, in U.S. Patents 2,027,962, 3,086,2~2 and 3,597,372. As is made clear in, for example, U.S. Patent 2,027-,962, the original di-mensionally heat-stable form may be a transient form in a con-tinuous process in which, for example, an extruded tube is expanded, whilst hot, to a dimensionally heat-unstable form but, ; in other applications, a preformed dimensionally heat stable article is deformed to a dimensionally heat-unstable form in a separate stage.
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In other articles, as described, for example, in British Patent 1,440,524, an elastomeric member such as an outer tubular member is held in a stretched state by a second member, such as an inner tubular member, which, upon heating, weakens and thus allows the elastomeric member to recover.
Heat-shrinkable sleeves find many applications, especially in the connection and termination of wires, cable and pipes.
However, there are other applications where it is desirable to provide a connecting, insulating or protective heat-recoverable member for elongated objects such as cables and pipes where the ends are not accessible or, if they are accessible, where it is undesirable to disconnect or otherwise displace them. For such applications so-called "wrap-around" sleeves have been de-veloped. Basically these are heat-recoverable sheets which can be wrapped round the substrate ~o form a generally tubular shape and which, in general, are provided with fastening means for holding them in the wrapped-up configuration during recovery. Typically such fastening means are mechanical in nature and comprise, for example, rigid clamps, pins, or channel members which co-operate with suitably shaped moulded or ex-truded protuberances ad3acent to the overlapping edges of the heat-recoverable sheet. Various types of fastening means are described, for example, in U.S. Patents 3,379,218 and British Patents 1,155,470, 1,211,988 and 1,346,479. In other appli-cations the sheet may be held in the wrapped-up configuration during recovery by means of an adhesive which may, in some cases, be applied on site.
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Wrap-around devices of the type described above have been successfully employed in many applications. However, in general, the previously proposed wrap-around devices have proved unsuitable for forming electrical connection, e.g. earth connections, to continuous substrates, e.g. elongate substrates having inaccessible ends, for example supply lines such as electric cables especially coaxial cables. With tubular heat-recoverable sleeves of unbroken cross-section it has proved possible to provide insert members made, for example, from solder, so that, on heating, recovery and the formation of a soldered connection occur simultaneously (as described, for example, in British Patent 1,062,043). This has been virtually impossible with wrap-around devices and, although it has been proposed in U.S. Patent 3,467,761 to use a wrap-around sleeve as an electrically shielded jacket around conductors and cables with provision for an earth connection, the sleeve is somewhat complicated and comprises a specially designed electrically conductive liner. Even with this, it is not possible simultan-eously to effect recovery and the ma~ing of the earth connection.
Thus to date, there has been no successful solution to this problem.
The present invention provides a method of forming an electrical connection to a substrate which comprises the steps of:
(a) positioning about the substrate a heat-recoverable wrap-around device which comprises heat-recoverable polymeric sheet material and retaining means which co-operates with and engages first and second regions of the s~eet material to 113718~;
maintain the device in a generally tubular form, the first and second regions being circumferentially spaced apart and the retaining means extending between the first and second regions, the retaining means being provided with means for receiving and engaging an electrical component to connect it electrically to the substrate positioned within the wrap-around device and the retaining means being positioned to make electrical contact, or to allow the electrical component to make electrical contact, with the substrate:
(b~ engaging an electrical component in said receiving means: and (b) heating said sheet material to cause recovery and.
to effect an electrical connection between said component and said substrate.
:~ 15 In accordance with the present invention there is also provided a heat-recoverable wrap-around device for forming an electrical connection to a substrate which comprises heat-recoverable polymeric sheet material and retaining means for co-operating with and engaging first and second regions of the 20 sheet material to maintain the device in a generally tubular ; form with the first and second regions circumferentially spaced apart and the retaining means extending between the . first and second regions, the retaining means being provided il with means for recelving an engaging an electrical component '.
so as to connect it electrically to a substrate positioned, ~ in use, within the wrap-around device, the device being such ~ that the retaining means can be positioned, in use, to make : electrical contact, or to allow the electrical component to : make electrical contact, with the substrate.
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~he invention further provides a wrap-around device according to the invention in combination with a substrate and an electrical component, the wrap-around device surround-ing the substrate.
As indicated above, in the assembled device the re-taining means co-operates with and engages first and second regions of the sheet material to maintain the device in a generally tubular form. Each of the first and second regions may be at an edge of the sheet itself or may be remote from an edge of the sheet itself. If desired a portion of the - heat-recoverable sheet material (preferably a portion adjacent to an edge of the sheet itself) may, in the assembled device, be positioned over the retaining means so as to insulate or otherwise protect it after recovery.
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113718~
By using the mechanical retaining means to form the electrical connection we have found that it is now possible to effect recovery and the formation of the connection in a s1ngle operation and the devices of the present invention are, there-fore, extremely use~ul in making electrical connections to continuous, i.e. elongate, substrates. One particularly useful application is in the connection o~ earth leads to the conductive sheaths o~ electric cables such as coa~ial cables.
In especially pre~erred embodiments of the present 1Q invention, the mechanical retaining mean$ is electrically-conductive, especially an electrically conducti~e buckle, generally made ~rom ~heet material such as copper, and is provided with means for receiving an electrical components, for example an earth lead, to facilitate formation of ths connection.
Such means may, for example, be provided by cutting or other-wi~e forming the retaining means to provide a ~m 11 bridge member under which the earth lead pa~ses ~o as to be held against the main bodg of the retaining means b~ resilient andjor irictional forces. Alternatively, the retaining means may comprise one or more slots in ~hich the earth lead is held, for example, by ~rictional ~orces.
The end o~ the electrical component for e~ample the earth lead, may be t~nned prior to in3erting it in the retaining mean~ and/or the retaining means it~el~ may be pro~ided with a solder pre~orm. I~ these measures are taken it is pos3ible to effect recovery and form a ~oldered connection in a single operatlon, which is especially advantageous.
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113718ci In many of the preferred wrap-around device3 used in accordance with the present invention, the surface of the devlce after recovery lies more or les~ flush with the surface of the substrate. Attention is drawn in this respect to copending Canadian Application Serial No. 318,516 inventors ~agardere and Sovi~h, filed December 22, 1978 claiming priority from ~riti2h Patent Application No. 53703/77, which describes and illustrates such devices. In these devices the mechanical retaining means does not need to pass through the body of the heat-recoverable member and thu~ the need for moulded or e~truded protuberances at - the edges of the heat-recoverable sheet i9 obviated. In this respect the mechanical retaining means generally compr~ses two sections which engage the first and second regions o~ the heat-recoverable sheet material. These sections typically comprise tines, which pass through 1OOPB in the ~heet material, or are provided with slots, through which the sheet material passes.
I In both such embodiments the heat-recoverable sheet material may be regarded a3 paAsing around these sections and, in many cases, it is engaged by frictional forces. r A flush configuration can readily be obtained by using a buckle as the mechanical retainiDg means. ~he buckle, ; which may, i~ desired, be contoured, e.g. curved, for con~ormity ; with the ~urface of the substrate, or which may be d~ormable 90 that it adopts the desired curved configuration during recsvery, may comprise one or more slots through which the sheet passes. In certain applications, it may be advantageous ~or the nature of the slots to be dif~erent, for e~ample, the ' 1 1 ~7 1 8 ~
slots may be clo~ed or open-ended. By this mea~s, for e~a~ple, it may be possible to attach the buckle to one end of the heat-recoverable sheet before it iS wrapped around the substrate, thus facilitating installation.
In some embodiments oi the present invention the heat-recoverable sheet material may be provided with loops on opposed edges thereof and the retaining meanq, e.g. the buckle, then preferably comprises two connected tinea each oi which pas3es th-ough a loop to hold the sheet in the wrap-around con-figuration. (Of course, the loop could also be provided onl~at one edge and it will be appreciated that many deRign modifi-cations are possible). ~he loops may be formed irom flat sheet material by iolding, preferably fo'lowed by bonding, for example by ultrasonic welding or, in certain em~odiments, by providing the heat-recoverable sheet member a~ a tube which becomes flatt-ened during the wrap-around operation to leave two edge loops 1-in its flattened configuration.
It will be appreciated that the use of a buckle will be especially appropriate when the width of the heat-recoverable sheet is Qmall, for e~ample where the device acts as a ~rap-around tie rather than as an insl-lPtive or protective closure de~ice, The buckle mP~ ii desired, be coated with a plastics iilm in one or more psrts for insulative purposes or to facilitate -~
assembly .
Depending on the application concerned, the heat-reco~erable sheet material can be made from any of the polymers known from the art to be useful for the production of heat-113718~
recoverable articles. Generally the sheet material will be ofcon~tant composition throughout; however lamin~tes of two different polymers bonded or fused together may be u~ed in certain instances. Among~t suitable polymers there may be mentioned, for e~ample, polyolefins, especially polyethylene, ~.
copolymer3 of ethyle~e and vinyl acetate, copolymers of ethylene and ethyl acrylate; chlorinated and fluorinated polymers, especi~lly polyvinyl chloride, polyvinylidene fluoride and polymers incorporating units from vinylidene fluoride, he~a-~luoroethylene and chlorotrifluoroethylene; a~d rubbers such asethylene/propylene rubber, chlorinated rubbers, e~g. ~eoprene, and silicone rubbers which may be used in a blend with a crystalline or glassy polymer such a~ an olefin polymer. A11 of the above materials may, if desired, be cros~-linked f~
e~ample by irradiation and/or chemical mean~, In certain applications, the internal sur~ace o~ the ~rap-arou~d sheet material may, of course, be provided with a coating of an adhe~ive or a sealant such a3 a hot-melt adhesive or a mastic. Especially suitable hot-melt adhesives include, for example, polyamides, ethylene/~inyl acetate copoly-mers and terpolymers (with or without incorporated waxes) and polyesters. Such materials are described, for e~ample, in British Patent 1,440,810 and German OS 2,709,717. Also suitable are curable adhesi~es which melt and flow on heating but which will not afterwards be hot-meltable. There may also be mentioned epo~y resins and conventional mastics such, for example, as tho3s based on butyl and isobutylene rubbers modified with suit- ¦
113718~i able materlal~ known in the art. Obviously the use or otherwise oi such materials and their type, ii chosen, will depend upon the particular requirementq in any given case.
It will be seen that the wrap-around de~ices used in the present invention can be iormed in a ~imple manner and there- !
iore that production costs can be kept very low, which i9 one of the main ad~antages provided by the ~resent invention.
Amongst other advantages there may especially be mentioned the ease oi installation of the devices, which are more or le~s independent oi manu¢acturing tolerance3 and other iactors contributing to the lack oi versatility oi the previously propo3ed mechanical fastening systems for ~rap-around device3.
Notwithstandinig the iact that the high degree oi recovery oi the sheet material itself allow~ the device~ to be used with different size substrates, the buckle arrangement enables the operator to position the de~ice accuratel~ and tightly around a~y 3ize oi substrate prior to recovery~ i Finally~ becau3ethe~buckle can itseli carr~ the 301der there i3 no diificulty in keeping the solder in position, which might otherwise be a problem with large sleeves.
Various embodiments oi the present invention will now be described, by way of e~ample o~ly, with reierence to the accompanying drawing~, in which Figures 1a and 1b illu~trate one form of wrap-around device and its use in making an electric~l connection;
~ igures 2a to 2d illustrate a second iorm of ~rap-around de~ice and its u~e in ma~ing an electrical connection;
113718~:i Figure 3 illustrates yet another form of wrap-around device suitable for use in the present invention;
~ igures 4a to 4d illu~trate a fourth form of wrap-around device suitable for use in the present invention; and Figures 5a to 5e illustrate a similar form of wrap-- around device.
Referring now to the drawings, Figures la and 1b show a wrap-around device according to the present invention comprising a strip of heat-recoverable material 1 which iB heat-Bhrinkable in it~ longitudlnal direction and a mechanical retaining means in the form of a thin metal buckle 2. ~he buckle is provided ~ith two ~ets of closed slots 3 and 4 through which the heat-recoverable strip passes. It is also formed to provide a central bridge 5. As shown, an earth lead 6 i5 held against the buckle 2 by this bridge 5. The end of braid 6 is preferably tinned with solder before it i9 inserted into the b~ckle 2.
This wrap around device ma~ be used to iorm an earth connection to the conductive sheath 7 of a cable 8. The device is assembled with the earth lead 6 a~ shown, for e~ample in Figure 1b, and i~ then wrapped about the ~heath 7 as ~hown in Figure 1a. Heat i9 then applied causing the strip 1 to shri~k loDgitudinall~ and the solder to flow and thus form the desired connection. It will be appreciated that the device i~ capable of adaptation to substrates of ~arious sizes because the length o~ the strip 1 may readil~ be varied.
Figures 2a to 2d illustrate a somewhat similar form of device e~cept that i~ this case the heat-shrinkable member is _ 1 0 --~1~37~8~
msde from a heat-shrinkable tube 11 as shown in ~igures 2a to 2c and that the buckle 12 is provided with two open-ended slots 13 and 14 80 that tines 15 and 16 respectively ma~ pas~ into the loops formed at the edges of the flattened tube 11. ~he a~sembly may be used to make an earth connection as shown, before recovery, in ~iguL~e 2d.
- In the wrap-around device ~hown in Figure 3, the retaining means comprises a metal clip 26 which operates on the hairpin principle in that it is provided with two parallel tines 27 and 28. However, in this case the retaining clip is addi-tionally provided with a base portion 29 which e~tends beneath the tines 27 and 28 and, as sho~n, operates to provide a sealirg ilap ~or the completed closure.
Figures 4a to 4d show a ~urther wrap-around device according to the present invention. This comprise~ a longitudi-- nally heat-shrinkable ~trip 31 and a metal buckle 32 which is advantageously made ~rom thin so~t copper. As can ~e seen ths width of strip 31 iB greater than that of buckle 32 a~, in this embodiment the strip i~ designed completely to cover the electri- ¦
cal connection made.
For this pUrpOBe~ as can be seen from Figure 4d, the arrangement is such that strip 31 overlaps itself when positioned on buckle 32~ The strip compri~es a longer end portion 33 provided with a ~ack-welded terminal loop 34 and a shorter en~
portion 35 provided ~ith 8 tack-welded terminal loop 36. ~he width o~ end portions 33 and 35 is less than that of huckle 32 as they are decigned to pass through the closed slots 37, 38 -- 1 1 _ ,:
113718~
snd 39 and the open ended 810t 40 of the buckle, respectlvely.
As shown in Figure 4c, the device may be provided a~sem-bled with loop 34 æurrounding the arm 41 between slots 37 and 38 after having been passed through slot ~9, the tack-weld bei~g formed in ~itu. Being made from thin soft copper the buckle 32 may bend to conform to a substrate, as shown in Figure 4d, and it may advantageously be coated with a thin fllm of a plastics material i~ the vicinity of open-ended slot 40 for electrical insulation purposes.
Prior to recovery, the device is assembled in the wrapped tubular configuration shown in Figure 4d with tine 42 of bracket 32 passing through loop 36 of heat-shriDkable strip 31. The edge portions of strip 31 bordering the dotted lines in - Figure 4a may be adhesive coated to provide an environmental seal.
~ he wrap-around device shown in Figures 5a to 5e is similar to that shown in Figures 4a to 4d. ~he difference i8 that the sheet member 51 i9 provided with terminal tagæ 52 and 53 which are not provided with loops. 3ecause of this the buckle 54 may be provided with closed ~lots as shown and the de~ice may be assembled and positioned about a substrate as illuætrated in Figures 5c and 5d. ~he absence of the terminal loops makes the construction of the device simpler and less e~penæive and, in addition, means that the device can more readily accommodate various si~es of cable.
Figure 5e shows how buckle 54 may be provided with a solder preform 55 æo that a soldered co~nection may be formed _ 12 -~ 1 ~7 on recovery.
Attention is drawn to copending Can~dian Appllcation Serial ~o. 318,5l7 inventor Francoise Biscop, filed December 22, 1978 claiming priority from Briti~h Patent Application ~o. 5~704/77, which describes wrap-around devices in which the two region~ of the sheet material which are secured together by a ~a3tening mean~ prior to recovery are each provlded with a strip oi relatively rigid sheet material, ior e~ample made irom metal and in which the strips, which lie generally in the plane o~ the sheet material, co-operate to iorm the fastening mean~ or a part thereof. Some oi the deviceY oi that inventio~
are.suitable for u~e in the present invention.
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, 11~371~;
In other articles, as described, for example, in British Patent 1,440,524, an elastomeric member such as an outer tubular member is held in a stretched state by a second member, such as an inner tubular member, which, upon heating, weakens and thus allows the elastomeric member to recover.
Heat-shrinkable sleeves find many applications, especially in the connection and termination of wires, cable and pipes.
However, there are other applications where it is desirable to provide a connecting, insulating or protective heat-recoverable member for elongated objects such as cables and pipes where the ends are not accessible or, if they are accessible, where it is undesirable to disconnect or otherwise displace them. For such applications so-called "wrap-around" sleeves have been de-veloped. Basically these are heat-recoverable sheets which can be wrapped round the substrate ~o form a generally tubular shape and which, in general, are provided with fastening means for holding them in the wrapped-up configuration during recovery. Typically such fastening means are mechanical in nature and comprise, for example, rigid clamps, pins, or channel members which co-operate with suitably shaped moulded or ex-truded protuberances ad3acent to the overlapping edges of the heat-recoverable sheet. Various types of fastening means are described, for example, in U.S. Patents 3,379,218 and British Patents 1,155,470, 1,211,988 and 1,346,479. In other appli-cations the sheet may be held in the wrapped-up configuration during recovery by means of an adhesive which may, in some cases, be applied on site.
., I
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Wrap-around devices of the type described above have been successfully employed in many applications. However, in general, the previously proposed wrap-around devices have proved unsuitable for forming electrical connection, e.g. earth connections, to continuous substrates, e.g. elongate substrates having inaccessible ends, for example supply lines such as electric cables especially coaxial cables. With tubular heat-recoverable sleeves of unbroken cross-section it has proved possible to provide insert members made, for example, from solder, so that, on heating, recovery and the formation of a soldered connection occur simultaneously (as described, for example, in British Patent 1,062,043). This has been virtually impossible with wrap-around devices and, although it has been proposed in U.S. Patent 3,467,761 to use a wrap-around sleeve as an electrically shielded jacket around conductors and cables with provision for an earth connection, the sleeve is somewhat complicated and comprises a specially designed electrically conductive liner. Even with this, it is not possible simultan-eously to effect recovery and the ma~ing of the earth connection.
Thus to date, there has been no successful solution to this problem.
The present invention provides a method of forming an electrical connection to a substrate which comprises the steps of:
(a) positioning about the substrate a heat-recoverable wrap-around device which comprises heat-recoverable polymeric sheet material and retaining means which co-operates with and engages first and second regions of the s~eet material to 113718~;
maintain the device in a generally tubular form, the first and second regions being circumferentially spaced apart and the retaining means extending between the first and second regions, the retaining means being provided with means for receiving and engaging an electrical component to connect it electrically to the substrate positioned within the wrap-around device and the retaining means being positioned to make electrical contact, or to allow the electrical component to make electrical contact, with the substrate:
(b~ engaging an electrical component in said receiving means: and (b) heating said sheet material to cause recovery and.
to effect an electrical connection between said component and said substrate.
:~ 15 In accordance with the present invention there is also provided a heat-recoverable wrap-around device for forming an electrical connection to a substrate which comprises heat-recoverable polymeric sheet material and retaining means for co-operating with and engaging first and second regions of the 20 sheet material to maintain the device in a generally tubular ; form with the first and second regions circumferentially spaced apart and the retaining means extending between the . first and second regions, the retaining means being provided il with means for recelving an engaging an electrical component '.
so as to connect it electrically to a substrate positioned, ~ in use, within the wrap-around device, the device being such ~ that the retaining means can be positioned, in use, to make : electrical contact, or to allow the electrical component to : make electrical contact, with the substrate.
.. , ' - 4a --: .
li371~;
~he invention further provides a wrap-around device according to the invention in combination with a substrate and an electrical component, the wrap-around device surround-ing the substrate.
As indicated above, in the assembled device the re-taining means co-operates with and engages first and second regions of the sheet material to maintain the device in a generally tubular form. Each of the first and second regions may be at an edge of the sheet itself or may be remote from an edge of the sheet itself. If desired a portion of the - heat-recoverable sheet material (preferably a portion adjacent to an edge of the sheet itself) may, in the assembled device, be positioned over the retaining means so as to insulate or otherwise protect it after recovery.
_ 4b -' ..
113718~
By using the mechanical retaining means to form the electrical connection we have found that it is now possible to effect recovery and the formation of the connection in a s1ngle operation and the devices of the present invention are, there-fore, extremely use~ul in making electrical connections to continuous, i.e. elongate, substrates. One particularly useful application is in the connection o~ earth leads to the conductive sheaths o~ electric cables such as coa~ial cables.
In especially pre~erred embodiments of the present 1Q invention, the mechanical retaining mean$ is electrically-conductive, especially an electrically conducti~e buckle, generally made ~rom ~heet material such as copper, and is provided with means for receiving an electrical components, for example an earth lead, to facilitate formation of ths connection.
Such means may, for example, be provided by cutting or other-wi~e forming the retaining means to provide a ~m 11 bridge member under which the earth lead pa~ses ~o as to be held against the main bodg of the retaining means b~ resilient andjor irictional forces. Alternatively, the retaining means may comprise one or more slots in ~hich the earth lead is held, for example, by ~rictional ~orces.
The end o~ the electrical component for e~ample the earth lead, may be t~nned prior to in3erting it in the retaining mean~ and/or the retaining means it~el~ may be pro~ided with a solder pre~orm. I~ these measures are taken it is pos3ible to effect recovery and form a ~oldered connection in a single operatlon, which is especially advantageous.
.~ .
113718ci In many of the preferred wrap-around device3 used in accordance with the present invention, the surface of the devlce after recovery lies more or les~ flush with the surface of the substrate. Attention is drawn in this respect to copending Canadian Application Serial No. 318,516 inventors ~agardere and Sovi~h, filed December 22, 1978 claiming priority from ~riti2h Patent Application No. 53703/77, which describes and illustrates such devices. In these devices the mechanical retaining means does not need to pass through the body of the heat-recoverable member and thu~ the need for moulded or e~truded protuberances at - the edges of the heat-recoverable sheet i9 obviated. In this respect the mechanical retaining means generally compr~ses two sections which engage the first and second regions o~ the heat-recoverable sheet material. These sections typically comprise tines, which pass through 1OOPB in the ~heet material, or are provided with slots, through which the sheet material passes.
I In both such embodiments the heat-recoverable sheet material may be regarded a3 paAsing around these sections and, in many cases, it is engaged by frictional forces. r A flush configuration can readily be obtained by using a buckle as the mechanical retainiDg means. ~he buckle, ; which may, i~ desired, be contoured, e.g. curved, for con~ormity ; with the ~urface of the substrate, or which may be d~ormable 90 that it adopts the desired curved configuration during recsvery, may comprise one or more slots through which the sheet passes. In certain applications, it may be advantageous ~or the nature of the slots to be dif~erent, for e~ample, the ' 1 1 ~7 1 8 ~
slots may be clo~ed or open-ended. By this mea~s, for e~a~ple, it may be possible to attach the buckle to one end of the heat-recoverable sheet before it iS wrapped around the substrate, thus facilitating installation.
In some embodiments oi the present invention the heat-recoverable sheet material may be provided with loops on opposed edges thereof and the retaining meanq, e.g. the buckle, then preferably comprises two connected tinea each oi which pas3es th-ough a loop to hold the sheet in the wrap-around con-figuration. (Of course, the loop could also be provided onl~at one edge and it will be appreciated that many deRign modifi-cations are possible). ~he loops may be formed irom flat sheet material by iolding, preferably fo'lowed by bonding, for example by ultrasonic welding or, in certain em~odiments, by providing the heat-recoverable sheet member a~ a tube which becomes flatt-ened during the wrap-around operation to leave two edge loops 1-in its flattened configuration.
It will be appreciated that the use of a buckle will be especially appropriate when the width of the heat-recoverable sheet is Qmall, for e~ample where the device acts as a ~rap-around tie rather than as an insl-lPtive or protective closure de~ice, The buckle mP~ ii desired, be coated with a plastics iilm in one or more psrts for insulative purposes or to facilitate -~
assembly .
Depending on the application concerned, the heat-reco~erable sheet material can be made from any of the polymers known from the art to be useful for the production of heat-113718~
recoverable articles. Generally the sheet material will be ofcon~tant composition throughout; however lamin~tes of two different polymers bonded or fused together may be u~ed in certain instances. Among~t suitable polymers there may be mentioned, for e~ample, polyolefins, especially polyethylene, ~.
copolymer3 of ethyle~e and vinyl acetate, copolymers of ethylene and ethyl acrylate; chlorinated and fluorinated polymers, especi~lly polyvinyl chloride, polyvinylidene fluoride and polymers incorporating units from vinylidene fluoride, he~a-~luoroethylene and chlorotrifluoroethylene; a~d rubbers such asethylene/propylene rubber, chlorinated rubbers, e~g. ~eoprene, and silicone rubbers which may be used in a blend with a crystalline or glassy polymer such a~ an olefin polymer. A11 of the above materials may, if desired, be cros~-linked f~
e~ample by irradiation and/or chemical mean~, In certain applications, the internal sur~ace o~ the ~rap-arou~d sheet material may, of course, be provided with a coating of an adhe~ive or a sealant such a3 a hot-melt adhesive or a mastic. Especially suitable hot-melt adhesives include, for example, polyamides, ethylene/~inyl acetate copoly-mers and terpolymers (with or without incorporated waxes) and polyesters. Such materials are described, for e~ample, in British Patent 1,440,810 and German OS 2,709,717. Also suitable are curable adhesi~es which melt and flow on heating but which will not afterwards be hot-meltable. There may also be mentioned epo~y resins and conventional mastics such, for example, as tho3s based on butyl and isobutylene rubbers modified with suit- ¦
113718~i able materlal~ known in the art. Obviously the use or otherwise oi such materials and their type, ii chosen, will depend upon the particular requirementq in any given case.
It will be seen that the wrap-around de~ices used in the present invention can be iormed in a ~imple manner and there- !
iore that production costs can be kept very low, which i9 one of the main ad~antages provided by the ~resent invention.
Amongst other advantages there may especially be mentioned the ease oi installation of the devices, which are more or le~s independent oi manu¢acturing tolerance3 and other iactors contributing to the lack oi versatility oi the previously propo3ed mechanical fastening systems for ~rap-around device3.
Notwithstandinig the iact that the high degree oi recovery oi the sheet material itself allow~ the device~ to be used with different size substrates, the buckle arrangement enables the operator to position the de~ice accuratel~ and tightly around a~y 3ize oi substrate prior to recovery~ i Finally~ becau3ethe~buckle can itseli carr~ the 301der there i3 no diificulty in keeping the solder in position, which might otherwise be a problem with large sleeves.
Various embodiments oi the present invention will now be described, by way of e~ample o~ly, with reierence to the accompanying drawing~, in which Figures 1a and 1b illu~trate one form of wrap-around device and its use in making an electric~l connection;
~ igures 2a to 2d illustrate a second iorm of ~rap-around de~ice and its u~e in ma~ing an electrical connection;
113718~:i Figure 3 illustrates yet another form of wrap-around device suitable for use in the present invention;
~ igures 4a to 4d illu~trate a fourth form of wrap-around device suitable for use in the present invention; and Figures 5a to 5e illustrate a similar form of wrap-- around device.
Referring now to the drawings, Figures la and 1b show a wrap-around device according to the present invention comprising a strip of heat-recoverable material 1 which iB heat-Bhrinkable in it~ longitudlnal direction and a mechanical retaining means in the form of a thin metal buckle 2. ~he buckle is provided ~ith two ~ets of closed slots 3 and 4 through which the heat-recoverable strip passes. It is also formed to provide a central bridge 5. As shown, an earth lead 6 i5 held against the buckle 2 by this bridge 5. The end of braid 6 is preferably tinned with solder before it i9 inserted into the b~ckle 2.
This wrap around device ma~ be used to iorm an earth connection to the conductive sheath 7 of a cable 8. The device is assembled with the earth lead 6 a~ shown, for e~ample in Figure 1b, and i~ then wrapped about the ~heath 7 as ~hown in Figure 1a. Heat i9 then applied causing the strip 1 to shri~k loDgitudinall~ and the solder to flow and thus form the desired connection. It will be appreciated that the device i~ capable of adaptation to substrates of ~arious sizes because the length o~ the strip 1 may readil~ be varied.
Figures 2a to 2d illustrate a somewhat similar form of device e~cept that i~ this case the heat-shrinkable member is _ 1 0 --~1~37~8~
msde from a heat-shrinkable tube 11 as shown in ~igures 2a to 2c and that the buckle 12 is provided with two open-ended slots 13 and 14 80 that tines 15 and 16 respectively ma~ pas~ into the loops formed at the edges of the flattened tube 11. ~he a~sembly may be used to make an earth connection as shown, before recovery, in ~iguL~e 2d.
- In the wrap-around device ~hown in Figure 3, the retaining means comprises a metal clip 26 which operates on the hairpin principle in that it is provided with two parallel tines 27 and 28. However, in this case the retaining clip is addi-tionally provided with a base portion 29 which e~tends beneath the tines 27 and 28 and, as sho~n, operates to provide a sealirg ilap ~or the completed closure.
Figures 4a to 4d show a ~urther wrap-around device according to the present invention. This comprise~ a longitudi-- nally heat-shrinkable ~trip 31 and a metal buckle 32 which is advantageously made ~rom thin so~t copper. As can ~e seen ths width of strip 31 iB greater than that of buckle 32 a~, in this embodiment the strip i~ designed completely to cover the electri- ¦
cal connection made.
For this pUrpOBe~ as can be seen from Figure 4d, the arrangement is such that strip 31 overlaps itself when positioned on buckle 32~ The strip compri~es a longer end portion 33 provided with a ~ack-welded terminal loop 34 and a shorter en~
portion 35 provided ~ith 8 tack-welded terminal loop 36. ~he width o~ end portions 33 and 35 is less than that of huckle 32 as they are decigned to pass through the closed slots 37, 38 -- 1 1 _ ,:
113718~
snd 39 and the open ended 810t 40 of the buckle, respectlvely.
As shown in Figure 4c, the device may be provided a~sem-bled with loop 34 æurrounding the arm 41 between slots 37 and 38 after having been passed through slot ~9, the tack-weld bei~g formed in ~itu. Being made from thin soft copper the buckle 32 may bend to conform to a substrate, as shown in Figure 4d, and it may advantageously be coated with a thin fllm of a plastics material i~ the vicinity of open-ended slot 40 for electrical insulation purposes.
Prior to recovery, the device is assembled in the wrapped tubular configuration shown in Figure 4d with tine 42 of bracket 32 passing through loop 36 of heat-shriDkable strip 31. The edge portions of strip 31 bordering the dotted lines in - Figure 4a may be adhesive coated to provide an environmental seal.
~ he wrap-around device shown in Figures 5a to 5e is similar to that shown in Figures 4a to 4d. ~he difference i8 that the sheet member 51 i9 provided with terminal tagæ 52 and 53 which are not provided with loops. 3ecause of this the buckle 54 may be provided with closed ~lots as shown and the de~ice may be assembled and positioned about a substrate as illuætrated in Figures 5c and 5d. ~he absence of the terminal loops makes the construction of the device simpler and less e~penæive and, in addition, means that the device can more readily accommodate various si~es of cable.
Figure 5e shows how buckle 54 may be provided with a solder preform 55 æo that a soldered co~nection may be formed _ 12 -~ 1 ~7 on recovery.
Attention is drawn to copending Can~dian Appllcation Serial ~o. 318,5l7 inventor Francoise Biscop, filed December 22, 1978 claiming priority from Briti~h Patent Application ~o. 5~704/77, which describes wrap-around devices in which the two region~ of the sheet material which are secured together by a ~a3tening mean~ prior to recovery are each provlded with a strip oi relatively rigid sheet material, ior e~ample made irom metal and in which the strips, which lie generally in the plane o~ the sheet material, co-operate to iorm the fastening mean~ or a part thereof. Some oi the deviceY oi that inventio~
are.suitable for u~e in the present invention.
Claims (31)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of forming an electrical connection to a sub-strate which comprises the steps of:
(a) positioning about the substrate a heat-recoverable wrap-around device which comprises heat-recoverable polymeric sheet material and retaining means which co-operates with and engages first and second regions of the sheet material to maintain the device in a generally tubular form, the first and second regions being circumferentially spaced apart and the retaining means extending between the first and second regions, the retaining means being provided with means for receiving and engaging an electrical component to connect it electrically to the substrate positioned within the wrap-around device and the retaining means being positioned to make electrical contact, or to allow the electrical component to make electrical contact, with the substrate:
(b) engaging an electrical component in said receiving means: and (b) heating said sheet material to cause recovery and to effect an electrical connection between said component and said substrate.
(a) positioning about the substrate a heat-recoverable wrap-around device which comprises heat-recoverable polymeric sheet material and retaining means which co-operates with and engages first and second regions of the sheet material to maintain the device in a generally tubular form, the first and second regions being circumferentially spaced apart and the retaining means extending between the first and second regions, the retaining means being provided with means for receiving and engaging an electrical component to connect it electrically to the substrate positioned within the wrap-around device and the retaining means being positioned to make electrical contact, or to allow the electrical component to make electrical contact, with the substrate:
(b) engaging an electrical component in said receiving means: and (b) heating said sheet material to cause recovery and to effect an electrical connection between said component and said substrate.
2. A method as claimed in claim 1 including the steps of folding back said heat-recoverable sheet material to form loops therein, and passing tines on said retaining means through said loops.
3. A method as claimed in claim 1 or claim 2, including the step of forming the loops by folding back opposed edge regions of the sheet material and securing the loops by bonding.
4. A method as claimed in claim 1 or claim 2, including the step of forming the loops by flattening a heat-recoverable tube to form a dual-walled sheet.
5. A method as claimed in claim 1, including the step of passing an electrical conductor under a bridge member on the retaining means so that the electrical conductor is held against the main body of the retaining means by resilient and/
or frictional forces.
or frictional forces.
6. A method as claimed in claim 1, including the step of attaching the retaining means to the first or second region of the heat-shrinkable sheet material prior to assembly of the wrap-around device for recovery.
7. A method as claimed in claim 1, which includes the step of positioning a portion of the heat-recoverable sheet material over the retaining means so as to insulate it after recovery.
8. A heat-recoverable wrap-around device for forming an electrical connection to a substrate which comprises heat-recoverable polymeric sheet material and retaining means for co-operating with and engaging first and second regions of the sheet material to maintain the device in a generally tubular form with the first and second regions circumferentially spaced apart and the retaining means extending between the first and second regions, the retaining means being provided with means for receiving and engaging an electrical component so as to connect it electrically to a substrate positioned, in use, within the wrap-around device, the device being such that the retaining means can be positioned, in use, to make electrical contact, or to allow the electrical component to make electrical contact, with the substrate.
9. A device in accordance with claim 8, in combination with a substrate and an electrical component, said wrap-around device surrounding said substrate.
10. A device as claimed in claim 9, wherein the electrical component is an earth conductor.
11. A device as claimed in claim 8 or claim 9, wherein the connection is made to a continuous substrate.
12. A device as claimed in claim 8 or claim 9, wherein the substrate is the conductive sheath of an electric cable.
13. A device as claimed in claim 8 or claim 9, wherein a portion of the heat-recoverable sheet material can be posi-tioned over the retaining means so as to insulate it after recovery.
14. A device as claimed in claim 8 or claim 9, wherein the retaining means is provided with a solder preform.
15. A device as claimed in claim 8 or claim 9, wherein the retaining means is such that the wrap-around device lies substantially flush with the substrate after recovery.
16. A device as claimed in claim 8 or claim 9, wherein the heat-recoverable sheet material of the wrap-around device is held in the retaining means by frictional forces.
17. A device as claimed in claim 8, wherein the retaining means is provided with two sections for engaging the said first and second regions of the heat-recoverable sheet material.
18. A device as claimed in claim 17, wherein said sections comprises tines for passing through loops in said heat-recoverable sheet material.
19. A device as claimed in claim 18, wherein said loops are formed at the edges of said heat-recoverable sheet material by folding back.
20. A device as claimed in claim 19, wherein the loops are secured by bonding.
21. A device as claimed in claim 18, wherein the said loops are formed by flattening a heat-recoverable tube to form a dual-walled sheet.
22. A device as claimed in claim 8, wherein said retaining means includes slots through which the heat-recoverable sheet material can pass.
23. A device as claimed in claim 22, wherein the heat-recoverable sheet material is provided as a strip the length of which can be altered according to the girth of the substrate.
24. A device as claimed in claim 8, wherein the retaining means is a buckle.
25. A device as claimed in claim 24, wherein the buckle is shaped to confirm with the substrate.
26. A device as claimed in claim 24, wherein the buckle is capable of deforming to conform to the substrate.
27. A device as claimed in claim 24, wherein the buckle is provided with a bridge member under which an electrical component such as an earth lead may pass so as to be held against the main body of the buckle by resilient and/or fric-tional forces.
28. A device as claimed in claim 24, wherein the width of the heat-recoverable sheet material is greater than that of the buckle and the arrangement is such that the heat-recover-able sheet material passes over the buckle so as to insulate it after recovery.
29. A device as claimed in claim 8, wherein the retaining means is made from an electrically conductive metal.
30. A device as claimed in claim 29, wherein said metal is copper.
31. A device as claimed in claim 8, wherein one or more parts of the retaining means is coated with a plastics material.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB53702/77A GB1604438A (en) | 1977-12-23 | 1977-12-23 | Electrical connections |
| GB53702/77 | 1977-12-23 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1137186A true CA1137186A (en) | 1982-12-07 |
Family
ID=10468699
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000318515A Expired CA1137186A (en) | 1977-12-23 | 1978-12-22 | Electrical connection using a heat-recoverable device and mechanical retaining means |
Country Status (4)
| Country | Link |
|---|---|
| CA (1) | CA1137186A (en) |
| DE (1) | DE2855602A1 (en) |
| FR (1) | FR2412968A1 (en) |
| GB (1) | GB1604438A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2243028A (en) * | 1990-03-31 | 1991-10-16 | Manweb Plc | Bonding device for lead sheathed cables. |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3312772A (en) * | 1963-08-23 | 1967-04-04 | Raychem Corp | Connectors with heat recoverable members |
| US3574313A (en) * | 1968-10-30 | 1971-04-13 | Raychem Corp | Wraparound closure sleeve |
| US3530898A (en) * | 1968-10-30 | 1970-09-29 | Raychem Corp | Closure sleeve |
| GB1503328A (en) * | 1975-11-21 | 1978-03-08 | Coal Ind | Split sleeve closures |
-
1977
- 1977-12-23 GB GB53702/77A patent/GB1604438A/en not_active Expired
-
1978
- 1978-12-21 FR FR7835910A patent/FR2412968A1/en active Pending
- 1978-12-22 CA CA000318515A patent/CA1137186A/en not_active Expired
- 1978-12-22 DE DE19782855602 patent/DE2855602A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| FR2412968A1 (en) | 1979-07-20 |
| GB1604438A (en) | 1981-12-09 |
| DE2855602A1 (en) | 1979-07-05 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |