GB2503892A

GB2503892A - Power cable apparatus

Info

Publication number: GB2503892A
Application number: GB201212227A
Authority: GB
Inventors: John James Philpott
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-07-10
Filing date: 2012-07-10
Publication date: 2014-01-15
Anticipated expiration: 2032-07-10
Also published as: GB2503892B; GB201212227D0

Abstract

A power cable apparatus has a power input means for connection to a power supply point and a power output means for connection to a caravan, motor home or water craft. The power input cable is wound on a drum 12, which is rotatable relative to both the power input means and the power output means due to slip-rings (24, 25, 48, Fig 10). The drum may be driven by an electric motor 17 and may have a clutch (47, Fig 9) to allow it to be unwound without using the motor.

Description

I

POWER CABLE APPARATUS

The present invention relates to a power cable apparatus for caravans, motor homes and water craft.

Power cables are known that employ a length of cable. One end of the cable is fitted with an electric plug and the other end of the cable is fitted with an electric socket.

When it is required to supply power to the caravan, motor home or water craft, the end of the cable fitted with the plug is plugged into a power supply point provided for this purpose and the end of the cable fitted with the socket is connected to a plug already fitted to the caravan, motor home or water craft. Power is then available inside the caravan, motor home or water craft to power electrical equipment.

A disadvantage with this arrangement is that when the caravan, motor home or water craft is connected to the power supply, lengths of cable are strewn all over the ground, looking untidy and offering a potential trip hazard. Another disadvantage with this arrangement is that when power supply is no longer required, normally because the caravan, motor home or water craft needs to be moved to a different location, the whole length of cable has to be wound up by hand and then a storage place within the caravan, motor home or water craft has to be found for the cable until such time as the cable is required again.

It is the aim of the present invention to provide an apparatus that alleviates these problems.

According to the present invention there is provided an apparatus for a power cable having power input means and a power output means for connection with a caravan, motor home or water craft, the cable being wound on a drum which is rotatable relative to both the power input means and the power output means to facilitate transmission of power to the caravan, motor home or water craft during winding in andlor unwinding of the cable.

Preferably the drum is rotatable on an axis relative to a frame or housing. Preferably, the frame or housing is fitted inside the caravan1 motor home or water craft either during production or as a retro fitted accessory.

Preferably the power input means comprises a contact means comprising a first portion fixed with respect to the frame and having a plurality of power contactors of an electrically conductive material for slideable contact with respect electrically conductive regions of a second portion fixed for rotation with the drum.

The power input means further comprises a contact means comprising a length of cable wound around the drum fitted with a plug for connection to the power supply point and the power output means by way of either a panel socket fitted to the frame or casing, allowing connection to the caravan, motor home or water craft, or by way of a short length of cable that can be connected to the electrical circuit inside the caravan, motor home or water craft by the manufacturers at the time of production or as a retro fit at a later date.

The advantage of this arrangement is that only the required amount of cable need be unwound from the drum to reach the power supply point and any unwanted cable remains stored neatly on the drum.

Another advantage of this arrangement is that power may be supplied to the cable even when the drum is rotating.

In a preferred frame or housing the apparatus further comprises an electric motor which is connected to the Direct Current electrical circuit inside the caravan, motor home or water craft.

Preferably, there is a switch mounted to the frame or housing which operates the electric motor.

Preferably, when the switch is engaged, the electric motor turns the drum via a gear linkage in order to rewind the cable when it is no longer required to be connected to the power supply point. The wound up cable is then stored neatly on the drum until it is next required.

Preferably, the embodiment houses a set of rollers which help to guide the cable smoothly onto or from the drum during winding or unwinding.

The apparatus further includes a thermal cut-out device to prevent the cable from overheating in the event that too much power is drawn from the apparatus.

The apparatus further includes a relay in the Direct Current circuit within the apparatus which will cut the Direct Current when the cable is connected to the power supply point.

This prevents the accidental rewinding of the cable by operating the switch whilst the cable is connected to the power supply point. Once the cable has been unplugged from the power supply, the relay closes, allowing the Direct Current to reach the motor in order to operate it.

Preferably the motor is connected to a torque limiter device which will cut the power to the motor should the cable be fouled or snagged during rewinding. This prevents the motor from overloading and causing damage to the motor or gear linkage.

Preferably, the gear linkage comprises a clutch mechanism comprising of a one way bearing which allows the cable to be unwound from the drum without turning the electric motor the wrong way and causing damage to the motor. This also allows the cable to be unwound virtually friction free.

Preferably the power input cable is connected to the drum by way of a connector so that in the event of the cable becoming damaged it can be replaced.

For the purposes of this specification, the phrase "wound in" shall be taken to refer to retraction of the to increase the portion of the cable wound around the drum, and the phrases "wound out" and "unwound" shall be taken to refer to extension of the cable to reduce the length of the portion wound around the drum.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a power cable apparatus.

Figure 2 is a plan view of a power cable apparatus.

Figure 3 is a front elevation of a power cable apparatus.

Figure 4 is a side elevation (right hand side) of a power cable apparatus.

Figure 5 is a rear elevation of a power cable apparatus.

Figure 6 is a side elevation (left hand side) of a power cable apparatus.

Figure 7 is a side elevation of the frame and the drum which are mounted inside the housing shown in figures 1 to 6.

Figure 8 is a front elevation of the frame and the drum which are mounted inside the housing shown in figures 1 to 6.

Figure 9 is a cross section in an axial plane through a drum showing the slideable power contactors.

Figure 10, 11, 12 and 13 show axial views of component parts of a power contactor device for use in the apparatus of figures ito 8.

Referring to figures 7 and 8, a power cable apparatus comprises a frame ha and hib.

A hollow drum 12 is mounted on an axle fixed to the frame and includes a cylindrical portion 13 and two flange portions 14a and 14b.

A thermal cut out device 15 is fitted inside the hollow drum to prevent overheating of the cable (not shown) which is wound around the drum when it is wound in.

On the opposite side of the drum (not shown) there is an aperture in which a cable connector is mounted. The cable which is to be wound in and unwound during use is connected to the cable connector which, in turn, is connected to the slideable power contactors.

A Direct Current electric motor is mounted to the frame and a gear (not shown) which is connected to the electric motor engages with a second gear 16 which is connected to the axel upon which the drum is mounted.

A one way bearing 47 is housed inside the gear 16 which allows the cable to be unwound by hand without turning the motor 17 and allows the motor 17 to turn the axle connected to the drum in order to wind in the cable.

Referring to figure 9, a power cable (not shown) is wound around the outer surface of the drum 13 such that an end portion is connected to the connector 18. The drum 12 is supported for rotation round axle 20 by bearing portions 21a and 21b. The end portion of the cable is provided with an input connector (not shown) for connection to the power supply point.

Referring to figures 9, 10, 11,12 and 13, a power contactor, referred to generally as 19, is mounted on the axle 20 and comprises a main body 22 which is fixed with respect to the frame and includes a first plate 23. The first plate 23 carries radially inner electrical contact elements 24, middle electrical contact elements 25 and outer electrical contact elements 48. The inner, middle and outer electrical contact elements 24, 25 and 48 are in slideable contact with respective electrically conductive regions of a second plate 26 forming part of the power contactor 19. The second plate 26 is fixed for rotation with the drum 12. An output cable (not shown) facilitates provision of output power through electrical connections from the electrical contact elements 24, 25 and 48. Electrical connections from the electrically conductive regions of the second plate 26 facilitate provision of input power from the input power cable (not shown) which connects to the connector 18.

In use, the input power cable is wound or unwound around the drum 12 and is retained between the flange portions 14a and 14b, as the drum is rotated about the axle 20.

A gear wheel 16 is mounted on the drum 12. In the embodiment of figures 7 and 8 the gear wheel 16 is mounted adjacent to the motor 17, whereas in the embodiment of figure 9 it is mounted adjacent to the power contactor 19. The gear wheel 16 is provided with a plurality of teeth arranged around its outer circumference 27. The teeth on the gear wheel 16 engage with the teeth on the gear (not shown) of the electric motor 17.

When the electric motor operates, the gear on the motor (not shown) turns the gear wheel 16 which, in turn, rotates the drum 12 and winds in the input power cable (not shown).

Referring to figures 10, the first portion 22 of the power contactor 19 comprises an inner ring 28 a middle ring 29 and an outer ring 50, formed by projections which extend from the face of a conductive metal. Typically, the sheet may be formed from copper. The inner ring 28, middle ring 29 and outer ring 50 are substantially coplanar and are separated by an annular gaps 30, 49 so as to be electrically insulated from each other.

The inner ring 28 includes three angularly spaced raised portions which are raised from the face of the sheet to define the inner electrical contact elements 24. The middle electrical contact elements 25 and outer electrical contact elements 48 are formed in the middle ring 29 and outer ring 50 in a similar way.

The second plate 26 of the power contactor 19 comprises an inner contact member 31 for contact with the inner electrical contact elements 24, a middle contact member 32 for contact with the middle electrical contact elements 25 and an outer contact member 51 for contact with the outer electrical contact elements 48. Both the inner, middle and outer contact members 31, 32 and 51 are formed of an electrically conductive material, such as brass. The inner contact member 31 has an annular region 33 having a smooth machined planar surface with the inner and outer radii which span the radius of the inner contact elements 24. The middle contact member 32 and outer contact member 51 have similar smooth machined annular regions 34,52 having inner, middle and outer radii which span the radius of the middle contact elements 25 and outer contact elements 48.

The first plate 23 and the inner, middle and outer contact members 31, 32 and 51 of the second plate 26 are axially aligned such that the inner electrical contact elements 24 contact the annular region 33 of the inner contact member 31 and the middle electrical contact elements 25 contact the annular region 34 of the middle contact member 32 and the outer electrical contact elements 48 contact the annular region 52of the outer contact member 51.. Electrical insulation material (not shown) is provided to separate the inner, middle and outer contact members 31, 32 and 51.

The first portion of the power contactor, main body 22, and the included first plate 23 are urged towards the second plate 26 such that the portions of the inner, middle and outer rings 28, 29 and 50, which define the inner, middle and outer electrical contact elements 24, 25 and 48 are deflected. The resilience of the metal sheet from which the electrical contact elements 24, 25 and 48 are formed serves to maintain contact between the contact elements 24, 25 and 48, and the contact members 31,32 and 51.

In use, the contact members 31, 32, 51 rotate with the drum 17 and the electrical contact elements 24, 25,48 are maintained in slideable contact with the annular regions 33, 34,52 of the contact members 31, 32 and 51 respectively, to ensure a constant electrical supply to the cable is available during rotation of the drum 12.

It will be appreciated that one of the benefits of the present invention is that the cable (not shown) is unwound by hand from the drum 12 or automatically wound back onto the drum, by the motor 17, by an appropriate amount as is required to reach the power supply point and any unwanted cable is stored neatly on the drum 12.

Referring to figures 1 to 6, the switch 35 is connected, by way of a Direct Current electrical circuit, to the motor. The Direct Current is supplied from the Direct Current electrical circuit in the caravan, motor home or water craft via connector 36. When the switch 35 is turned, the electric motor 17 operates and turns the drum 12. The output power is supplied to the caravan, motor home or water craft via connector 37.

The power input cable (not shown) which winds around the drum 12 passes through a set of roller guides 38 which are mounted inside the housing 39. The roller guides 38 help to guide the cable smoothly onto the drum 12 when the switch 35 is turned.

The housing 39 is provided with air vents 46 to help keep the input cable (not shown) cool. The housing 39 is further provided with ventilation holes 43, 44 for the same purpose.

Rubber feet 40 are fixed to the housing 39 to protect the apparatus from possible damage caused when the caravan, motor home or water craft are in transit.

The housing 39 is provided with an aperture 41 to allow access to the thermal cut-out device 15 (Figure 8). The aperture 41 is large enough for a human hand to pass through it in order to reset the thermal cut-out device 15 if and when required.

The housing 39 is fitted with a power indicator light 42 which lights up when the input cable (not shown) is connected to the power supply point.

Claims

CLAIMS1. A power cable apparatus having a power input means for connection to a power supply point and a power output means for connection to a caravan, motor home or water craft, the input cable being wound on a drum (12) which is rotatable relative to both the power input means and the power output means to facilitate transmission of power to a caravan, motor home or water craft during winding in and/or unwinding of the input cable.
2. The apparatus of claim 1, further comprises an electric motor (17) for applying a drive to axle (20) via gear (16)to rotate the drum (12).
3. The apparatus of claim 2, wherein the apparatus is further provided with a switch (35) to operate the motor (17).
4. The apparatus of claim 3, wherein the apparatus is provided with a one way bearing or clutch (47) to allow the unwinding of the power input cable without turning the motor (17).
5. The apparatus of claim 4, wherein the apparatus is further provided with a power outlet socket (37) to allow the apparatus to be connected to the electrical circuit inside the caravan, motor home or water craft and to, thus, provide power to the caravan, motor home or water craft.
6. The apparatus of claim 6, wherein the apparatus is further provided with a power inlet cable which is wound around the drum (12) and can be unwound and connected to a power supply point allowing power to travel through the input power cable and reach the power outlet socket (37) via the power contactor (19).
7. The apparatus of claim 7, wherein the apparatus comprises a drum (12) mounted to a frame (11 a, 11 b) by way of axle (20) and enclosed in a housing (39) allowing the housing (39), and its content components, to be mounted inside a caravan, motor home or water craft using mounting points (45) during production of new caravans, motor homes or water craft or as a retro fit accessory for used caravans, motor homes or water craft.