WO1987007756A1 - Electric power cables - Google Patents

Electric power cables Download PDF

Info

Publication number
WO1987007756A1
WO1987007756A1 PCT/GB1987/000383 GB8700383W WO8707756A1 WO 1987007756 A1 WO1987007756 A1 WO 1987007756A1 GB 8700383 W GB8700383 W GB 8700383W WO 8707756 A1 WO8707756 A1 WO 8707756A1
Authority
WO
WIPO (PCT)
Prior art keywords
electric power
power cable
cable according
outer sleeve
coil
Prior art date
Application number
PCT/GB1987/000383
Other languages
French (fr)
Inventor
Brian James Hazzard
Original Assignee
Powersafe Cables Ltd.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Powersafe Cables Ltd. filed Critical Powersafe Cables Ltd.
Priority to AT8787903383T priority Critical patent/ATE104797T1/en
Priority to DE3789672T priority patent/DE3789672T2/en
Priority to EP87903383A priority patent/EP0391891B1/en
Publication of WO1987007756A1 publication Critical patent/WO1987007756A1/en
Priority to GB8828837A priority patent/GB2214698B/en
Priority to CY189096A priority patent/CY1890A/en

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/06—Extensible conductors or cables, e.g. self-coiling cords
    • H01B7/065—Extensible conductors or cables, e.g. self-coiling cords having the shape of an helix

Definitions

  • This invention relates to electric power cables and is particularly but not exclusively concerned with electric power cables for use with electrical appliances having cutting means such as electric lawn mowers, and electric saws.
  • Conventional electric power cables comprise a plurality of conductive cores, usually 2 or 3 copper wires each surrounded by a flexible insulative coating usually of plastics material and usually held together within a flexible protective sheath, again usually of plastics material.
  • electric power cables have been constructed so that they tend to lie generally flat on the ground or other surface between the appliance and an electrical power source. This has been found to have certain disadvantages and in particular when used with electric lawn mowers and when used in long lengths between the power source and the appliance. Firstly, as the cable tends to lie flat along the ground, the cable can easily become obscured from the view of the user of the appliance. For example, in use with an electric lawn mower working in long grass, a conventional cable may become hidden in the grass.
  • an electric power cable comprising a resilient helically formed sleeve encasing electric wiring.
  • an electric power cable comprising an electri ⁇ cally-conductive core within a sheath; in which the sheath is at least partially encased within a resilient sleeve and the sleeve forms at least a partial loop.
  • an electric power cable comprising an electri ⁇ cally-conductive core within an insulating layer, a flexible sheath at least partially encasing the core and layer and a resilient outer sleeve at least partially encasing the flexible sheath and formed so that the cable is resiliently extendable between a contracted condition and an extended condition.
  • the resilient outer sleeve may be formed so that the cable forms a partial lodp.
  • the cable may be formed into a series of resilient loops along its length.
  • the resilient outer sleeve is formed as a helical coil. In the contracted condition, the turns of the coil may lie closely adjacent to each other. Thus, in the contracted condition the coil may be easily gripped in one hand by a user.
  • the coil may have a diameter of at least 100 mm, and preferably, about 1 0 mm.
  • a power cable of such a diameter is preferable in that it can not be run over by a lawn mower, in use, the lawn mower simply pushing the cable aside.
  • such a cable is advant ⁇ ageous in that the diameter of the coil enhances the cable 's visibility and reduces the possibility of the cable becoming obscured from the view of the user.
  • the coil may have an extended length to contracted length ratio of greater than 10:1.
  • the coil has an extended length to contracted length ratio of * about 36:1.
  • Such a cable is advantageous in that as the
  • the resilient sleeve may have a wall thickness of 0.5 to 2.0 mm.
  • the resilient sleeve has a wall thickness of 0.5 to 0.8 mm.
  • the diameter of the resilient sleeve may be about 10 m , and perferably from 6 to 7 nun.
  • the power cable may have a connection means in electrically-conductive communication with the core.
  • the connection means may comprise a socket or a plug.
  • the cable has a plug at one of its ends and a socket at the other end.
  • the resilient sleeve may be made from a plastics material such as nylon. It is preferred that the material be resistant to mechnical and chemical damage. Furthermore, it is preferred that the sleeve be finished in a vivid colour e.g. fluoresent orange or yellow to enhance its visibility.
  • the cable may have 2 or 3 said cores, each of which is at least partially encased within an insulating layer and which may be held together by the aforesaid flexible sheath.
  • Fig. 1 is a side view of a power cable in accordance with the invention shown partly cut awayj
  • Fig. 2 is a cross-section of a portion of the cable on line A-A in Fig 1; and
  • Fig. 3 is a side view of a power cable in accordance with the invention having an attached connection means at the ends thereof.
  • the electric power cable 1 shown in Fig. 1 comprises a resilient outer sleeve 10 containing electric wiring indicated generally at 12.
  • a sleeve 10 is made of nylon and is formed into a resilient helix.
  • the wiring 12 is of conventional construction comprising 3 conductive cores of copper wire 13 > l4jl5 each surrround- ed by an insulating layer, 13a, 14a, 15a respectively, and held together within a flexible P.V.C. sheath 16.
  • the cable is shown in a slightly extended condition, and has an extended to contracted length ratio of 36:1.
  • The. helical coil has an external diameter of approximately 140 mm.
  • the wall thickness of the resilient sleeve 10 is approximately 0.5 nun and its diameter is 6 to 7 tarn.
  • the power cable 20 shown in Fig. 3 is of similar construction to the power cable 10 of Figs. 1 and 2 and corresponding features are given the same reference numeral.
  • a conventional plug 22 is attached to one end 24 of the cable to permit connection of the cable to an electric power source.
  • the other end 26 of the cable 20 may be provided with a socket 22a to form an extension lead, or may be directly connected to an appliance e.g. a lawn mower.
  • the outer sleeve 10 extends along the sheath 16 to the plug 22. ' This arrangement is advantageous in that in use, the tension in the helical coil tends to tip the plug 22 in the socket comprising the electric power source, thus tending to lock the plug in position in the socket and inhibiting accidental withdrawal of the plug.
  • the sleeve 10 may be arranged so as to not extend to the connection means. Such an arrangement would be advantageous in a situation where access to the electrical power source were restricted and the greater flexibility of the uncovered sheath would permit easier insertion or withdrawal of the plug.

Abstract

Electric power cable comprising an electrically-conductive core within an insulating layer, a flexible sheath at least partially encasing the core and layer and a resilient outer sleeve encasing the flexible sheath and formed so that the cable is resiliently extendable between a contracted condition and an extended condition.

Description

ELECTRIC POWER CABLES
Technical Field
This invention relates to electric power cables and is particularly but not exclusively concerned with electric power cables for use with electrical appliances having cutting means such as electric lawn mowers, and electric saws.
Background Art
Conventional electric power cables comprise a plurality of conductive cores, usually 2 or 3 copper wires each surrounded by a flexible insulative coating usually of plastics material and usually held together within a flexible protective sheath, again usually of plastics material. Hitherto, electric power cables have been constructed so that they tend to lie generally flat on the ground or other surface between the appliance and an electrical power source. This has been found to have certain disadvantages and in particular when used with electric lawn mowers and when used in long lengths between the power source and the appliance. Firstly, as the cable tends to lie flat along the ground, the cable can easily become obscured from the view of the user of the appliance. For example, in use with an electric lawn mower working in long grass, a conventional cable may become hidden in the grass. Fatal accidents have occurred when .power cables have become obscured from the view of the user in this way and the mower has cut through the cable, electrocuting the user. Attempts at mitigating this particular disadvantage have included providing the cable with a vividly coloured sheath. Electronic circuit breakers have also been provided but these are complex and prone to failure. Furthermore, to avoid cutting the cable, the user has to re-arrange the cable continually to ensure that it does not lie in the path of the mower.
It is the object of the invention to mitigate the foregoing disadvantages.
Disclosure of the Invention
According to one aspect of the invention there is provided an electric power cable comprising a resilient helically formed sleeve encasing electric wiring.
According to another aspect of the invention there is provided an electric power cable comprising an electri¬ cally-conductive core within a sheath; in which the sheath is at least partially encased within a resilient sleeve and the sleeve forms at least a partial loop.
According to a further aspect of the invention there is provided an electric power cable comprising an electri¬ cally-conductive core within an insulating layer, a flexible sheath at least partially encasing the core and layer and a resilient outer sleeve at least partially encasing the flexible sheath and formed so that the cable is resiliently extendable between a contracted condition and an extended condition. fl
. . The resilient outer sleeve may be formed so that the cable forms a partial lodp. The cable may be formed into a series of resilient loops along its length. Preferably, the resilient outer sleeve is formed as a helical coil. In the contracted condition, the turns of the coil may lie closely adjacent to each other. Thus, in the contracted condition the coil may be easily gripped in one hand by a user.
The coil may have a diameter of at least 100 mm, and preferably, about 1 0 mm. A power cable of such a diameter is preferable in that it can not be run over by a lawn mower, in use, the lawn mower simply pushing the cable aside. Furthermore, such a cable is advant¬ ageous in that the diameter of the coil enhances the cable 's visibility and reduces the possibility of the cable becoming obscured from the view of the user.
The coil may have an extended length to contracted length ratio of greater than 10:1. Preferably, the coil has an extended length to contracted length ratio of * about 36:1. Such a cable is advantageous in that as the
- ' coil can be resiliently extended, it is unnecessary for the user to gather up or pay out the cable as is required with conventional cables when the appliance is used at a distance from the power source.
The resilient sleeve may have a wall thickness of 0.5 to 2.0 mm. Preferably, the resilient sleeve has a wall thickness of 0.5 to 0.8 mm.
The diameter of the resilient sleeve may be about 10 m , and perferably from 6 to 7 nun.
The power cable may have a connection means in electrically-conductive communication with the core. The connection means may comprise a socket or a plug. Preferably, the cable has a plug at one of its ends and a socket at the other end.
The resilient sleeve may be made from a plastics material such as nylon. It is preferred that the material be resistant to mechnical and chemical damage. Furthermore, it is preferred that the sleeve be finished in a vivid colour e.g. fluoresent orange or yellow to enhance its visibility.
The cable may have 2 or 3 said cores, each of which is at least partially encased within an insulating layer and which may be held together by the aforesaid flexible sheath.
Brief Description of Drawings
An electric power cable in accordance with the invention will now be described by way of example only with reference to the accompanying drawings, Figs. 1,2 and 3 > in which:
Fig. 1 is a side view of a power cable in accordance with the invention shown partly cut awayj Fig. 2 is a cross-section of a portion of the cable on line A-A in Fig 1; and Fig. 3 is a side view of a power cable in accordance with the invention having an attached connection means at the ends thereof. The electric power cable 1 shown in Fig. 1 comprises a resilient outer sleeve 10 containing electric wiring indicated generally at 12. A sleeve 10 is made of nylon and is formed into a resilient helix. The wiring 12 is of conventional construction comprising 3 conductive cores of copper wire 13>l4jl5 each surrround- ed by an insulating layer, 13a, 14a, 15a respectively, and held together within a flexible P.V.C. sheath 16. The cable is shown in a slightly extended condition, and has an extended to contracted length ratio of 36:1. The. helical coil has an external diameter of approximately 140 mm. The wall thickness of the resilient sleeve 10 is approximately 0.5 nun and its diameter is 6 to 7 tarn.
The power cable 20 shown in Fig. 3 is of similar construction to the power cable 10 of Figs. 1 and 2 and corresponding features are given the same reference numeral. A conventional plug 22 is attached to one end 24 of the cable to permit connection of the cable to an electric power source. The other end 26 of the cable 20 may be provided with a socket 22a to form an extension lead, or may be directly connected to an appliance e.g. a lawn mower.
It will ne noted that the outer sleeve 10 extends along the sheath 16 to the plug 22.' This arrangement is advantageous in that in use, the tension in the helical coil tends to tip the plug 22 in the socket comprising the electric power source, thus tending to lock the plug in position in the socket and inhibiting accidental withdrawal of the plug.
However, if desired the sleeve 10 may be arranged so as to not extend to the connection means. Such an arrangement would be advantageous in a situation where access to the electrical power source were restricted and the greater flexibility of the uncovered sheath would permit easier insertion or withdrawal of the plug.
In the contracted condition the coils of the cable lie closely adjacent each other, e.g. touching as shown in broken lines at 30 in Fig. 3-
Industrial Applicability
Whilst the invention has been described with the particular reference to power cables for the use with lawn mowers it will be appreciated the cables in accordance with the invention will find numerous other applications e.g. in workshops, in view of their advantages over conventional power cables.

Claims

- ? -
1. An electric power cable comprising an electrically- conductive core within an insulating layer, a flexible sheath at least partially encasing the core and layer and a resilient outer sleeve encasing the flexible sheath and formed so that the cable is resiliently extendable between a contracted condition and an extended condition.
2. An electric power cable according to Claim 1 in which the resilient outer sleeve is formed so that the cable forms a partial loop.
3. An electric power cable according to Claim 1 or 2 which is formed into a series of resilient loops along its length.
4. An electric power cable according to Claim 1,2 or 3 in which the resilient outer sleeve is formed as a helical coil.
5. An electric power cable according to Claim 4 in which in the contracted condition the turns of the coil lie closely adjacent each other.
ό. An electric power cable according to Claim 4 or 5 - 3 -
in which the coil has a diameter of at least 100 mm.
7. An electric power cable according to Claim 6 in which the coil has a diameter of about 140 mm.
8. An electric power cable according to Claim 4,5,6 or 7 in which the coil has an extended length ratio to contracted length ratio of greater than 10:1.
9. An electric power cable according to Claim 8 in which the coil has an extended length to contracted length ratio of about 36:1.
10. An electric power cable according to any preceding claim in which the outer sleeve has a wall thickness of 0.5 to 2.0 mm.
11. An electric power cable according to Claim 10 in which the outer sleeve has a wall thickness of 0.5 to 0.8 mm.
12. An electric power cable according to any preceding claim in which the diameter of the outer sleeve is at least 5 πim.
13- An electric power cable according to Claim 12 in which the diameter of the outer sleeve is 6 to 7 mm. - <\ -
14. An electric power cable according to any preceding claim which has a connection means in electrically- conductive communication with the core.
15• An electric power cable according to Claim 14 in which the connection means is a socket.
16. An electric power cable according to Claim 14 or 15 in which the connection means is a plug.
17. An electric power cable according to any preceding claim in which the outer sleeve is formed from a nylon- based material.
PCT/GB1987/000383 1986-06-03 1987-06-03 Electric power cables WO1987007756A1 (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
AT8787903383T ATE104797T1 (en) 1986-06-03 1987-06-03 ELECTRICAL POWER CABLES.
DE3789672T DE3789672T2 (en) 1986-06-03 1987-06-03 ELECTRIC POWER CABLES.
EP87903383A EP0391891B1 (en) 1986-06-03 1987-06-03 Electric power cables
GB8828837A GB2214698B (en) 1986-06-03 1988-12-02 Electric power cables
CY189096A CY1890A (en) 1986-06-03 1996-08-30 Electric power cables

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB868613435A GB8613435D0 (en) 1986-06-03 1986-06-03 Electric power cables
GB8613435 1986-06-03

Publications (1)

Publication Number Publication Date
WO1987007756A1 true WO1987007756A1 (en) 1987-12-17

Family

ID=10598850

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1987/000383 WO1987007756A1 (en) 1986-06-03 1987-06-03 Electric power cables

Country Status (6)

Country Link
EP (1) EP0391891B1 (en)
CY (1) CY1890A (en)
DE (1) DE3789672T2 (en)
GB (2) GB8613435D0 (en)
HK (2) HK171595A (en)
WO (1) WO1987007756A1 (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1257810A (en) * 1968-04-19 1971-12-22
US3993860A (en) * 1975-08-18 1976-11-23 Samuel Moore And Company Electrical cable adapted for use on a tractor trailer
DE7738998U1 (en) * 1977-12-21 1978-04-06 Wolf-Geraete Gmbh, 5240 Betzdorf Electric cable for mains operation

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1257810A (en) * 1915-03-30 1918-02-26 Louis H Clark Apron.
FR1573437A (en) * 1967-07-03 1969-07-04

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1257810A (en) * 1968-04-19 1971-12-22
US3993860A (en) * 1975-08-18 1976-11-23 Samuel Moore And Company Electrical cable adapted for use on a tractor trailer
DE7738998U1 (en) * 1977-12-21 1978-04-06 Wolf-Geraete Gmbh, 5240 Betzdorf Electric cable for mains operation

Also Published As

Publication number Publication date
DE3789672D1 (en) 1994-05-26
GB8613435D0 (en) 1986-07-09
HK171595A (en) 1995-11-17
GB8828837D0 (en) 1989-03-22
HK173595A (en) 1995-11-17
GB2214698A (en) 1989-09-06
EP0391891A1 (en) 1990-10-17
EP0391891B1 (en) 1994-04-20
CY1890A (en) 1996-08-30
GB2214698B (en) 1991-02-13
DE3789672T2 (en) 1994-11-17

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