WO2001012466A1

WO2001012466A1 - Vehicle seat back heater

Info

Publication number: WO2001012466A1
Application number: PCT/AU2000/000939
Authority: WO
Inventors: Robin Stanley Wiseman; Julie Ann Wiseman
Original assignee: Robin Stanley Wiseman; Julie Ann Wiseman
Priority date: 1999-08-12
Filing date: 2000-08-07
Publication date: 2001-02-22

Abstract

A vehicle seat heating pad (1) adapted to be located against an outer support surface of a backrest (2) of a vehicle seat, the pad (1) including an electrical connector (8) adapted to be inserted into the cigarette lighter socket of a vehicle, the pad (1) including distributed electrical conductors within the pad (1), and switch means (11) to effect a selection of the electrical conductors, whereby there is provided a first extent of heating from a first switch position and a second extent of heating from a second switch position.

Description

VEHICLE SEAT BACK HEATER

This invention relates to a warming pad intended for use on the back of a vehicle seat.

It is known for manufacturers to provide as original equipment heating integrated within vehicle seats.

It is proposed in accordance with this invention that there be provided as an accessory a warming pad adapted to be positioned between the vehicle seat and a user which is supplied with heating electrical current from the electrical power supply of the vehicle.

The problem to which this invention is directed is the difficulty that, where such a device is to be an accessory for a motor vehicle, it will need to be connected to a power supply within the vehicle which can supply a significant level of electrical current and which can be easily accessed by an intending user. Such a connection is the electrical cigarette lighter socket which is conventionally available in every vehicle.

The problem however with such a socket is that this will supply electrical current from the battery of the motor vehicle whether or not the ignition of the motor vehicle is switched on or not or whether the engine is running or not.

The problem then is that a person can use such an accessory to significantly drain current from the motor vehicle battery without realizing that this might be the case. For instance sitting in the vehicle in circumstances where heating is beneficial but where running the motor would be inappropriate to maintain charging of the vehicle battery eg at a drive in picture theatre.

The disadvantage of running a battery flat is well known to those who have experienced this and it is an object of this invention to propose an arrangement which will at least to some extent assist in at least reducing this possibility.

In one form of this invention then, although this need not necessarily be the only or indeed the broadest form of this, there is proposed a vehicle seat heating pad including an electrical connector adapted to be connected to a power supply of a motor vehicle and including distributed electrical conductors within the pad to provide a source of heat when electrical current flows there through, and switch means to effect a selection of some of said electrical conductors for electrical connection to said power supply.

In a further form of this invention then there is proposed a heating pad to be located lying against a support surface of the back of a vehicle seat where the pad includes an electrical connector to be inserted into the cigarette lighter socket of a motor vehicle to gain access to a power supply thereby, the pad including distributed electrical conductors within the pad to provide a source of heat when electrical current flows there through, and switch means to effect a selection of said electrical conductors whereby there is provided a first extent of heating from a first switch position and in respect of a second switch position, a different degree of heating from the first.

It is well known that when a person might first commence use of a car where heating is to be used, that there is a first period during which the pad will be relatively cold, and this is the most uncomfortable period until heating reaches comfortable levels. In an unregulated current control system then, continued heating might reach temperatures which are not only uncomfortable but perhaps dangerous.

If then, there is provided a high heat position, there is provided in accordance with this invention, means to effect through a high electrical current a quicker raising of temperature through resistance wires in the pad to minimise a thermal inertia effect.

It is well known for instance to have electric blankets for beds which are supplied power through a mains alternating electrical supply and in order to overcome the thermal inertia problem, many will arrange to have the blankets switched on a significant time before the bed is to be occupied.

This is an eminently sensible thing to do when there is an essentially unlimited power supply available whereas it is not a sensible thing to do when the power supply is from a limited source such as a car battery which if left unattended for any significant period of time, could well fully discharge the battery.

Accordingly, in a preferred feature, there is provided that there is a switch with the pad, which is positioned so that the electrical resistance wires will only be connected electrically to the plug and therefore as appropriate any source of power when there is an applicable pressure on the pad in the vicinity of the switch to effect the switching of this under such pressure.

This however of itself accentuates the other problem which is the initial thermal inertia and hence it will be seen that if the pad is only to be warming once a person is in place in the seat in the vehicle, then there needs to be an initial rapid warming effect which, as a matter of time, increase the temperature of the pad quickly.

Once a comfortable temperature has been reached however, it is then appropriate to keep the pad at an acceptable comfortable temperature and to this end, there are provided switch means to allow for switching between the two relative positions.

One of the problems associated with the use of such a heating pad for a seat in a motor vehicle with two electrical current and therefore heating positions of a switch, is that there will be significant advantage if the switch should be located so that in all applications of the various types of motor vehicle, it will be readily accessible and visible.

Unfortunately, many designers of motor vehicles locate the cigarette lighter socket in a position in which it is not easily visible to a driver and what this can mean is that the driver will not necessarily easily know through any easily accessible visual signal that the heating pad is in either an off position, a low heat or high heat position.

As the power and therefore heating does not come on at all until the driver is actually sitting in the seat, it will take some reasonable time for the driver then to discern that heating is occurring and herein lies the problem.

It is a problem being considered by this invention which is to enable in a very effective way, the user of the thermal device, to determine whether it is connected to the heating and secondly in which status is the heating being provided or at least available when the pressure pad is operated.

In accord with this invention, there are light means coupled to circuit means such that there will be a light effected which can be distinctively recognised as indicating to a user that the switch is in at least one of the heating positions. In preference, there are two separate lights which are separately and uniquely identifiable so that when the light is shining, the user can positively establish that heating is occurring and in what status this is being made available.

If a switch and lights are incorporated into a plug which can be fed into the cigarette lighter socket, then there can be provided at least two lights which can be independently indicative of a high or low heat setting in connection with the pad.

It is to be noted that this then varies from any previous resistance heating system where there are not the constraints of a limited power supply, limited easy access to an indicator required for a universal fitting application, and the potential need to overcome an initial thermal inertia quickly.

For a better understanding of this invention it will now be described in relation to a preferred embodiment which shall be described with the assistance of drawings wherein

Figure 1 is a perspective view of the embodiment as it could be expected to be used in a motor vehicle, with a plug in a position to be located within an appropriate socket within the motor vehicle,

Figure 2 is an enlargement of the plug about to be positioned within the cigarette lighter socket, the plug including a switch and two lights which would indicate the selected position being either for high heating or low heating,

Figure 3 is a side view of the plug showing some instructional elements,

Figure 4 is the same side view as in Figure 3 showing however further electrical connections with mechanical parts being not shown,

Figure 5 is an illustration of one pattern of resistance wiring within the pad showing the electrical connections to provide for two heat settings, and

Figure 6 is an exploded view of a further embodiment.

Referring now in detail to the drawings, the pad 1 is intended to be positioned on the front surface of the back of vehicle seat such as at 2 and the embodiment shows the pad 3 supported by tapes 4 which are tied around stalks supporting the headrest 5. Each pad has a front layer and a back layer both of which are chosen to be of a material which is self supporting fibrous material which is selected to provide a relatively stiff support for electrical resistance wiring but also will provide a pressure averaging effect so that any pressure switch will be activatable by pressure derived from a broader area of pressure against the pad 1 and also protect the resistance wiring from having to conform with sharp bends where for instance the pad is pressed back into the shape of the front face of a vehicle seat. This stiffer material also has the effect of protecting the warming resistance elements from being excessively bent to conform for instance to the shape of a back of a car seat. The degree of stiffness of each pad is such that they will generally maintain a broad rather than a narrow curvature under normal usage. This will then assist in maintaining a longer life for the resistance wires and reduce any risk of bending stress fracturing of these in the very demanding location of the back of a vehicle seat.

Within the pad 1 and between appropriate pad layers, is a pattern of resistance wiring arranged as specifically shown in Figure 5 so as to provide relatively uniform heating across the pad and connected so that there are two separate wiring situations so that for a given voltage, in a first position, there will be a lower heating condition as compared to a second connection. (The arrangement shown is appropriate for a 24 volt supply but a different arrangement can be used for a 12 volt supply).

As a first advantageous feature, there is provided a pressure switch 6 which is positioned at a lower end of the pad 1 so as to provide an electrical contact only in the event that pressure is being applied to the switch and thus allow heating only in the event that a person is actually sitting in the seat.

This is not to say that the switch 6 cannot be operated in other ways but of course its purpose is to provide a reasonably automatic safety factor both from undue discharge of a battery and also safety from obtaining an overheating effect in the event that the high setting is left for too long in wrong conditions.

An electrical cord 7 connects the pad 3 to a plug 8.

The plug 8 includes a traditional electrically connecting male end at 9 which is adapted to fit within a cigarette lighter socket 10. A switch 11 has three positions a middle one of which is in an off position so that there is no electrical circuit made to the pad 3, and in a first position which is to say forward in figure 2, this will be such that a first selected extent of resistance wires in the pad will be connected to the voltage supply of the vehicle and further, the switching also interconnects the voltage supply to a light emitting diode of a selected colour (for low heat setting green is appropriate and for the high heat setting red is considered appropriate) at 12.

When the switch 11 is in the opposite position, there is a further different network of resistance wires in the pad 3 connected and the light emitting diode 13 is appropriately lit.

The internal circuitry and the mechanisms to achieve this are shown more extensively in Figures 3 and 4.

One feature is that the illumination of the light emitting diodes 12 or 13 are affected by contacts through the switch so that they are illuminated appropriately when the switch position is in the appropriate position and are not illuminated simply by the passage of current through the switch to the electrical resistance wiring.

This has the advantage that the illumination of the light emitting diodes will indicate that there is a power supply available and will indicate the position of the switch but will not be turned on or off simply when the user might for instance lean forward to view the plug and further, they will be illuminated whether or not a person is actually using the pad provided the plug is located in the socket and the switch is in either the low or high position.

Accordingly, there will be a high possibility of anybody then noticing that this is in an effective and operating position and can take appropriate action for instance to switch the switch to an off position or even remove the socket when appropriate.

This is especially beneficial when it might not be apparent for some time that the heating is on for instance on a day in which it is implicitly quite warm and the battery might be accidentally lowered in charge in situations which are not appropriate.

The circuit in Figure 4 includes three electrical wires at 14, 15 and 16 where 14 is connected only through the switch 6. This then provides for alternate connections to the separate circuits shown in the one case as the thinner lines at 17 and in the other case as the thicker lines at 18.

Referring to the further embodiment as shown as an exploded view in Figure 6, there are two outer pads 20 and 21 which are selected from a long lasting fibrous matting material which are cut so that they are left to join at 22 and therefore will fold up together and can be kept in that position either by stitching or by appropriate application of a gluey material.

Captured between the two members 20 and 21 however is the heating element 23 which is held between two linen sheets 24 and 25 which capture between them the electrical resistant element material 23 and these are held together by appropriate silicon based sealant which also acts as a glue.

In this embodiment, there are two pressure pads 26 in the one case and 27 in the other both of which are operating in parallel so that provided one of these is closed, then a circuit is made from the battery supply through to the resistant element.

There are tapes at 28 which pass through the element 20 at 29 and which is joined at 30 by being glued to the inner face of the element 20.

This is an alternate construction to an arrangement in which the tape is continuously extending between the aperture 29 through to the aperture 31 and this will have the effect of gathering together the top of the member 20 which can be unsightly.

When the assembled arrangement is then finally joined, for instance, by sewing, the tape 20 at 30 is captured and further held permanently in position.

This further embodiment is however further joined to the plug and lighting arrangements previously described.

The construction shown in the earlier embodiment is substantially the same as shown in Figure 6.

Claims

1. A vehicle seat heating pad including an electrical connector adapted to be connected to a power supply of a motor vehicle and including distributed electrical conductors within the pad to provide a source of heat when electrical current flows there through, and switch means to effect a selection of some of said electrical conductors for electrical connection to said power supply.

2. A vehicle seat heating pad adapted to be located against an outer support surface of a back of a vehicle seat, the pad including an electrical connector adapted to be inserted into the cigarette lighter socket of a motor vehicle to gain access to a power supply thereby, the pad including distributed electrical conductors within the pad to provide a source of heat when electrical current flows there through, and switch means to effect a selection, in one case, of some and not all of said electrical conductors for electrical connection to the cigarette lighter socket.

3. A vehicle seat heating pad as in the immediately preceding claim further characterized in that the switch means to effect a selection of said electrical conductors are such that there is provided a first extent of heating from a first switch position and in respect of a second switch position, a different degree of heating from the first switch position.

4. A vehicle seat heating pad as in either one of the immediately preceding claims further characterized in that the pad is comprised of materials such that it will maintain a shape following a broad curvature only when under normal usage.

5. A vehicle seat heating pad as in the immediately preceding claim further characterized in that the pad is comprised of two side portions each of which is a relatively stiff sheet of a fibrous material.

6. A vehicle seat heating pad as in either one of the preceding claims further characterised in that there is switch within the pad adapted and positioned to effect a closing of a connecting circuit to the pad when being pressed against by a user of the pad.

7. A vehicle seat heating pad as in any one of the preceding claims further characterised in that the switch means are located so that there is a light that will be visible by a user of the pad.

8. A vehicle seat heating pad as in any one of the preceding claims further characterised in that there are light means coupled to circuit means such that there will be a light effected which indicate to a user that the switch is in at least one of the selected heating positions and effecting a connection of electrical heating to the pad.

9. A vehicle seat heating pad as in the immediately preceding claim further characterised in that there are two separate lights which are each separately and uniquely identifiable so that when one of the lights is shining, the user is informed that heating is occurring.

10. A vehicle seat heating pad as in the immediately preceding claim further characterised in that there is the switch and lights incorporated into a plug which can be inserted into a cigarette lighter socket, and so that there are at least two lights which are independently indicative of either a high or low heat setting for the pad.

11. A vehicle seat heating pad as in any one of the preceding claims further characterised in that the pad has tapes which are adapted to be tied around stalks supporting a headrest of a motor vehicle seat to be supported thereby.

12. A vehicle seat heating pad as in any one of the preceding claims further characterised in that, within the pad and between appropriate pad layers, is a pattern of resistance wiring arranged so as to provide relatively uniform heating across the pad and connected so that there are two separate wiring situations so that for a given voltage, in a first position, there will be a lower heating condition as compared to a second connection.

13. A vehicle seat heating pad as in any one of the preceding claims further characterised in that the switch has three positions, a middle one of which is in an off position so that there is no electrical circuit made to the pad, and in a first position this will be such that a first selected extent of resistance wires in the pad will be connected to the voltage supply of the vehicle and further, the switching also interconnects the voltage supply to a light emitting diode of a selected colour and when the switch is in the opposite position, there is a further different network of resistance wires in the pad connected and the light emitting diode is appropriately connected to be lit.

15. A vehicle seat heating pad as in any one of the preceding claims further characterised in that the illumination of the light emitting diodes is affected by contacts through the switch so that they are illuminated appropriately when the switch position is in the appropriate position and are not illuminated simply by the passage of current through the switch to the electrical resistance wiring.

16. A vehicle seat heating pad as in any one of the preceding claims further characterised in that there are two outer pad sheets of material which are selected from a long lasting fibrous matting material which are cut so that they are left to be joined and therefore will fold up together and can be kept in that position either by stitching or by appropriate application of a glue .

17. A vehicle seat heating pad as in any one of the preceding claims further characterised in that captured between the two members is the heating element which is held between a first two linen sheets which capture between them the electrical resistant element material and these are held together by appropriate silicon based sealant which also acts as a glue.

18. A vehicle seat heating pad as in any one of the preceding claims further characterised in that there are two pressure pads both of which are operating in parallel so that provided one of these is closed, then a circuit is made from the battery supply through to the resistant element.

19. A vehicle seat heating pad as in any one of the preceding claims further characterised in that there are tapes which pass through the element and which are joined by being glued to the inner face of the element .