EP0391891B1 - Electric power cables - Google Patents
Electric power cables Download PDFInfo
- Publication number
- EP0391891B1 EP0391891B1 EP87903383A EP87903383A EP0391891B1 EP 0391891 B1 EP0391891 B1 EP 0391891B1 EP 87903383 A EP87903383 A EP 87903383A EP 87903383 A EP87903383 A EP 87903383A EP 0391891 B1 EP0391891 B1 EP 0391891B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- cable
- coil
- electric power
- contracted
- electric
- 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 - Lifetime
Links
- 239000000463 material Substances 0.000 description 4
- 239000004033 plastic Substances 0.000 description 3
- 229920003023 plastic Polymers 0.000 description 3
- 244000025254 Cannabis sativa Species 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 239000004677 Nylon Substances 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 229920001778 nylon Polymers 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 230000000116 mitigating effect Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Images
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 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 as a helical coil so that the cable is resiliently extendable between a contracted and an extended condition characterised in that the coil has an extended length to contracted length ratio of greater than 10:1 and in that the wall thickness of the resilent sleeve is 0.5 to 0.8 mm.
- the turns of the coil may lie closely adjacent to each other.
- 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 140 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 advantageous 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 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 diameter of the resilient sleeve may be about 10 mm, and preferably from 6 to 7 mm.
- 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 mechanical and chemical damage. Furthermore, it is preferred that the sleeve be finished in a vivid colour e.g. fluorescent 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.
- the electric power cable 1 shown in Figure 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, 14, 15 each surrounded 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 mm and its diameter is 6 to 7mm.
- the power cable 20 shown in Figure 3 is of similar construction to the power cable 10 of Figures 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.
Landscapes
- Insulated Conductors (AREA)
Abstract
Description
- 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. 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. DE-U-7738998 discloses an electric power cable in accordance with the preamble of
claim 1. - It is the object of the invention to mitigate the foregoing disadvantages.
- According to one aspect of the invention there is provided 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 as a helical coil so that the cable is resiliently extendable between a contracted and an extended condition characterised in that the coil has an extended length to contracted length ratio of greater than 10:1 and in that the wall thickness of the resilent sleeve is 0.5 to 0.8 mm.
- 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 140 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 advantageous 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.
- 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 diameter of the resilient sleeve may be about 10 mm, and preferably from 6 to 7 mm.
- 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 mechanical and chemical damage. Furthermore, it is preferred that the sleeve be finished in a vivid colour e.g. fluorescent 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.
- An electrical power cable in accordance with the invention will now be described by way of example only with reference to the accompanying drawings, Figures 1,2, and 3, in which:
- Figure 1 is a side view of a power cable in accordance with the invention shown partly cut away;
- Figure 2 is a cross-section of a portion of the cable on line A-A in Figure 1; and
- Figure 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 Figure 1 comprises a resilientouter sleeve 10 containing electric wiring indicated generally at 12. Asleeve 10 is made of nylon and is formed into a resilient helix. Thewiring 12 is of conventional construction comprising 3 conductive cores ofcopper wire 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 theresilient sleeve 10 is approximately 0.5 mm and its diameter is 6 to 7mm. - The
power cable 20 shown in Figure 3 is of similar construction to thepower cable 10 of Figures 1 and 2 and corresponding features are given the same reference numeral. Aconventional plug 22 is attached to oneend 24 of the cable to permit connection of the cable to an electric power source. Theother end 26 of thecable 20 may be provided with asocket 22a to form an extension lead, or may be directly connected to an appliance e.g. a lawn mower. - It will be noted that the
outer sleeve 10 extends along thesheath 16 to theplug 22. This arrangement is advantageous in that in use, the tension in the helical coil tends to tip theplug 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 Figure 3.
- 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 (6)
- An electric power cable (1) comprising an electrically-conductive core (13,14,15) within an insulating layer (13a,14a,15a), a flexible sheath (16) at least partially encasing the core and layer and a resilient outer sleeve (10) encasing the flexible sheath (16) and formed as a helical coil so that the cable is resiliently extendable between a contracted and an extended condition characterised in that the coil has an extended length to contracted length ratio of greater than 10:1 and in that the wall thickness of the resilient sleeve is from 0.5 to 0.8 mm.
- An electric power cable (1) according to claim 1 in which the coil has an extended length to contracted length ratio of about 36:1.
- An electric cable (1) according to claim 1 or 2 in which in the contracted condition the turns of the coil lie closely adjacent each other.
- An electric cable (1) according to claim 1,2, or 3 in which the coil has a diameter (d) of at least 100 mm.
- An electric cable (1) according to claim 4 in which the coil has a diameter (d) of about 140 mm.
- An electric power cable according to any preceding claim which has a connection means (22,22a) in electrically-conductive communication with the core (13,14,15).
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT8787903383T ATE104797T1 (en) | 1986-06-03 | 1987-06-03 | ELECTRICAL POWER CABLES. |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB8613435 | 1986-06-03 | ||
GB868613435A GB8613435D0 (en) | 1986-06-03 | 1986-06-03 | Electric power cables |
PCT/GB1987/000383 WO1987007756A1 (en) | 1986-06-03 | 1987-06-03 | Electric power cables |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0391891A1 EP0391891A1 (en) | 1990-10-17 |
EP0391891B1 true EP0391891B1 (en) | 1994-04-20 |
Family
ID=10598850
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP87903383A Expired - Lifetime EP0391891B1 (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 (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR1573437A (en) * | 1967-07-03 | 1969-07-04 |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1257810A (en) * | 1915-03-30 | 1918-02-26 | Louis H Clark | Apron. |
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 |
-
1986
- 1986-06-03 GB GB868613435A patent/GB8613435D0/en active Pending
-
1987
- 1987-06-03 DE DE3789672T patent/DE3789672T2/en not_active Expired - Fee Related
- 1987-06-03 WO PCT/GB1987/000383 patent/WO1987007756A1/en active IP Right Grant
- 1987-06-03 EP EP87903383A patent/EP0391891B1/en not_active Expired - Lifetime
-
1988
- 1988-12-02 GB GB8828837A patent/GB2214698B/en not_active Expired - Lifetime
-
1995
- 1995-11-09 HK HK171595A patent/HK171595A/en not_active IP Right Cessation
- 1995-11-09 HK HK173595A patent/HK173595A/en not_active IP Right Cessation
-
1996
- 1996-08-30 CY CY189096A patent/CY1890A/en unknown
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR1573437A (en) * | 1967-07-03 | 1969-07-04 |
Also Published As
Publication number | Publication date |
---|---|
GB2214698B (en) | 1991-02-13 |
EP0391891A1 (en) | 1990-10-17 |
DE3789672D1 (en) | 1994-05-26 |
HK173595A (en) | 1995-11-17 |
GB2214698A (en) | 1989-09-06 |
WO1987007756A1 (en) | 1987-12-17 |
HK171595A (en) | 1995-11-17 |
DE3789672T2 (en) | 1994-11-17 |
GB8828837D0 (en) | 1989-03-22 |
GB8613435D0 (en) | 1986-07-09 |
CY1890A (en) | 1996-08-30 |
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