GB2404069A - Obstacle detector in a storage compartment for a retractable folding vehicle roof - Google Patents

Abstract

A vehicle such as a convertible car (fig. 1,2) has a folding roof (10) stowable in a, possibly shared, storage compartment (18a, 18b) of the car (fig. 1,2), where the top of the compartment (18a) is for the roof and the bottom of the compartment (18b) is for luggage. Preferably the folding roof is powered and can be actuated by a manual switch (17) my the user. An infra-red optical sensor system 100 monitors the storage compartment to detect any obstacles in the path of the roof which would hinder its stowage. Preferably this system produces a multiple light transmitters and receivers positioned so monitoring beams cross the storage compartment at the maximum safe luggage height (h in fig. 3). If an obstacle is detected a warning alert is produced and the roof is not permitted to be moved (fig 5).

Description

DETECI ION SYSTEM

The present invention relates to a detection system and particularly, but not exclusively, to a system for detecting or sensing the presence of an object in a roof storage compartment of a vehicle having a folding roof structure.

Vehicles, such as automobiles, having folding roof structures are well known and are commonly referred to as "convertibles" or "cabriolets". There are two main types of cabriolet vehicle: the first, more common type, is the "soft-top cabriolet" having a roof structure formed almost entirely from a flexible fabric material which is stretched over a folding frame. The frame is collapsible between a folded and a non-folded position of the roof, in the folded position the flexible material folding or creasing naturally as the frame collapses to be stored in a roof storage area in the rear of the vehicle, either in a compartment located between the vehicle seats and the luggage compartment or seated on top of the luggage compartment or parcel shelf.

The second form of cabriolet vehicle is the "hard-top cabriolet". Hardtop cabriolet vehicles, which are comparatively rare, include a so-called "retractable hard-top" (RHT), this being a roof structure formed of two or more rigid panels which are pivotally connected together. A linkage, such as a parallelogram linkage, supports the panels and permits movement of the panels between a first, non-folded position of the roof structure and a second, folded position. In the first, non-folded position, the roof structure covers the passenger compartment or cabin of the vehicle giving the appearance of a conventional, non-convertible or fixed roof vehicle.

In the folded position, the roof structure is folded on the frame, each panel pivoting relative to each other, often in a "clam-shell" type movement. The folded roof structure is most commonly stored in a roof storage compartment comprising an upper region of the vehicle luggage compartment, the hatch door or tailgate of which is arranged to open to permit access of the folded roof structure therein. Such hard-top cabriolet vehicles are well known and an example of a vehicle having an RHT, and the operation thereof, is described in US 6,299,234.

A problem with such vehicles is that the luggage compartment of the vehicle usually performs the function of both the roof storage compartment for storage of the folded roof structure and of a conventional luggage compartment for the storage of luggage. It is frequently possible to store luggage in the vehicle luggage compartment when the roof structure is folded and stored in the roof storage compartment, there being sufficient space within the luggage compartment to achieve this simultaneous dual function.

However, a problem arises in that the luggage stored must not exceed a predetermined volume if the roof storage compartment is to remain sufficiently clear to enable the folded roof structure to be stored at the same time. In particular, the maximum height of the luggage, from the base or floor of the luggage area to the highest point thereof, must not exceed a predetermined limit. Luggage exceeding this height limit will interfere with the roof structure in its folded position which can cause considerable damage to the folding mechanism.

Heretofore, this problem has been solved by providing a retractable tonneau cover within the luggage compartment, located at a height corresponding to, or marginally lower than, the predetermined height limit referred to in the preceding paragraph. If the user of the vehicle wishes to carry luggage in the luggage compartment and also intends to fold the roof of the vehicle during use, he/she must confirm that the luggage stored does not exceed the height limit by extending the tonneau cover over the luggage. If the tonneau cover does not extend over the luggage freely, the user can establish that the luggage in the luggage compartment is too high and that if the roof structure is moved to its folded position, the luggage will interfere with or obstruct the movement, possibly causing damage to the roof or to the folding mechanism.

There are a number of disadvantages to this crude system. Firstly, providing such a tonneau cover on the vehicle is relatively expensive and the cover does not provide any additional function other than its intended purpose, namely to ensure that the roof structure can operate correctly.

Secondly, the cover must be put in place by the user immediately after any luggage has been loaded into the luggage compartment, i.e. before the vehicle itself is moved. This is acceptable if the roof structure is to be moved to the folded position before the vehicle itself is driven. Frequently, however, it will be desired to move the roof structure to the folded position whilst the vehicle is in motion, or at least from within the vehicle cabin. In this instance, it is not possible to do so without having to exit the vehicle either to move the cover into position or to check that luggage in the luggage compartment has not moved during earlier driving manoeuvres such that it now exceeds the predetermined height limit.

It would be an advantage to provide a less expensive system which can automatically detect whether any obstruction exists in the luggage compartment, without significant manual intervention from the user, and preferably while the vehicle itself is in motion.

It is an aim of the present invention to address the aforementioned problems and to provide a system which provides one or more of the advantages described in the preceding paragraph.

According to one aspect of the present invention, therefore, there is provided a detection system for an automobile having a folding roof structure arranged to be moved between a first, non-folded position in which the roof structure substantially covers the passenger compartment of the vehicle and a second, folded position in which the roof structure is stored in a storage compartment of said vehicle, the system comprising transmitter means for generating and transmitting a signal across at least a portion of said storage compartment, receiver means for receiving said signal and control means for controlling the movement of the roof structure in dependence thereon.

Preferably, the transmitter means is arranged to generate an optical signal, more preferably an infrared (JR) signal.

The system may additionally comprise switch means for manual operation by a user of the vehicle to select movement of the roof structure between the first I and second positions. On operation of the switch means by the user, the control means may be arranged to generate a TRANSMIT signal to the transmitter means. The transmitter means may be operable to transmit said optical signal in response to said TRANSMIT signal.

The receiver means may be arranged to generate a RECEIVED signal on receiving said optical signal. The RECEIVED signal may be applied to the control means which controls the movement of the roof structure in dependence thereon. The control means may be arranged to generate an OPERATE signal which may be applied to a motor or other drive mechanism for the roof structure, thereby to move the roof structure between the first and second positions.

The system may additionally comprise indicator means for generating an audible, visual, tactile or other signal to alert the user of the vehicle.

If the receiver means does not receive said optical signal, or receives only a portion of said optical signal, the receiver means may be arranged to generate a NOT RECEIVED signal which is applied to the control means. On receipt of the NOT_RECEIVED signal, the control means may be arranged to generate an ERROR signal, said ERROR signal being applied to said indicator means.

The indicator means may be arranged to generate the alert signal on receipt of said ERROR signal. On receipt of the NOT RECEIVED signal, the control means does not generate the OPERATE signal and the roof structure is not moved between the first and second positions.

The transmitter means may comprise one or more optical transmitters such as IR diodes and the receiver means may comprise one or more optical receivers, such as IR photodiodes, LDRs or CCDs.

One or both of the transmitter means and the receiver means may be movable within the storage compartment. Alternatively, one or both of the transmitter means and the receiver means may be fixed within the storage compartment.

According to another aspect of the invention there is provided a method of detecting an object within a storage compartment of a vehicle having a folding roof structure, the method comprising generating and transmitting a signal across at least a portion of said storage compartment, monitoring whether said signal is received and controlling the operation of said roof structure in dependence thereon.

In the system and method of the invention, as described in the preceding paragraphs and hereinafter, a signal is transmitted across at least a portion of the roof storage compartment and/or the luggage compartment of the vehicle. If any luggage within the luggage compartment exceeds a predetermined height, the signal will not be received, or will only partially be received. In this case, the control unit will not allow the roof structure to be moved and the indicator means will alert the user to the excessive luggage height. Only when the signal is fully received will the control unit permit the roof structure to be moved between the first and second positions.

The present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 illustrates a known folding roof structure for a vehicle in its non- folded position; Figure 2 shows the roof structure of Figure 1 in its folded position; s Figure 3 illustrates a known system for detecting obstructions in the roof storage compartment of a vehicle; Figure 4 illustrates a first form of detection system according to the invention; and Figure 5 is a flow diagram illustrating the operation of the system of Figure 4; Referring to firstly to Figures 1 and 2, a known folding roof structure for a vehicle is shown generally at 10. The roof structure is formed of two main parts, a roof part 12 and a rear-window part 14 which is pivotally connected thereto. In a first, closed or non-folded position of the roof structure 10, as illustrated in Figure 1, the roof part 12 is oriented generally horizontally and a front edge region 13 thereof engages with a frame 15 of the vehicle windscreen. In this position, the rear-window part 14 engages with the roof part 12 substantially to cover the cabin or passenger compartment 6 of the vehicle.

Both the first and second parts 12, 14 are substantially rigid and are generally formed from metal, glass or similarly rigid materials so as to give the appearance, when in the first, non-folded position, that the vehicle is a conventional fixed-roof vehicle and not a cabriolet. This is in contrast with so- called "soft-top" cabriolets whose roof structure is formed from a fabric material and is generally highly flexible. I The roof structure 10 is arranged to be moved or folded from the first nonfolded position shown in Figure 1 to a second, folded position illustrated in Figure 2. A linkage (not shown) is provided which allows the rear-window part 14 to pivot or rotate in a rearward direction (clockwise in the drawings) about a pivot point 17 over an arc of approximately 90 . This pivoting movement is achieved by a positive drive mechanism (not shown) drivingly connected to the linkage.

As the rear-window part 14 rotates, it carries with it the roof part 12 which, due to the nature of the linkage and the pivoting connection between the two parts, remains substantially horizontal throughout the rearward movement of the roof structure 10. The movement of the roof structure 10 is such that, when the rear- window part 14 has pivoted through its full range of rotation, the entire passenger compartment 6 is uncovered, as illustrated in Figure 2.

Storage of the roof structure 10 in its second, folded position is achieved by means of a roof storage compartment 18a, located towards the rear of the vehicle. In practice, the roof storage compartment forms an upper part of the luggage compartment 18b of the vehicle, and is not separated or divided therefrom or compartmentalized in any way. Movement of the folded roof structure 10 into the roof storage compartment 18a is achieved by the opening of a rearwardly pivoting trunk lid or tailgate 19 which provides access to the roof storage compartment 18a.

The folded roof structure 10 is pivoted into the roof storage compartment 18a by the positive drive mechanism, and in the second position the roof part 12 lies substantially directly above the rear window part 14 and both parts are substantially horizontally oriented. Such roof structures, and the construction and operation thereof are well known and are described, for example, in US6,299,234. As such, further details of roof structures of this type are not included herein but will be well understood by those skilled in the art.

As stated above, the roof storage compartment 18a forms an upper part of the vehicle luggage compartment 18b and thus, when the roof structure 10 is in the second, folded position and stored therein, the available space within the luggage compartment 18b is reduced. In order for the roof structure 10 to be folded correctly and, in particular, to be stored within the roof storage compartment 18a, it is necessary to ensure that any luggage in the luggage compartment 18b does not encroach into the roof storage compartment 18a.

In particular, the height or depth of the luggage in the luggage compartment 18b must be less than a predetermined limit. If that limit is exceeded, that is to say, if the height of the luggage in the luggage compartment is too great, then the luggage will interfere with the roof structure 10 in the second, folded position.

Specifically, if the height of the luggage in the luggage compartment exceeds the predetermined limit, it will obstruct the full movement of the folding roof structure 10 into the second, folded position and the roof structure will contact with the luggage before it is in its storage position. The positive drive mechanism will endeavour to drive the roof structure 10 into its storage position but will be prevented from doing so by the engagement of the roof structure with the luggage. This can cause considerable damage to the positive drive mechanism and/or to the roof structure itself.

To reduce or eliminate this problem, it is conventional to provide a retractable rigid or semi-rigid tonneau cover in the luggage compartment 18b/roof storage compartment 18a, as illustrated in Figure 3. The tonneau cover 30 is mounted on a spool 32 which is positioned in a forward region of the luggage compartment 18b at a height corresponding substantially to the interface between the roof storage compartment 18a and the remainder of the luggage compartment; in other words, at or just below the level (dashed line h) at which the roof structure 10 in its folded position would be located.

In use, the user of the vehicle can load the luggage compartment 18b with luggage and is then able to check that the height of the luggage does not exceed the predetermined limit, and hence will not interfere with or obstruct the full folding movement of the roof structure, by extending the tonneau cover 30 which is disposed at a level substantially corresponding to the predetermined height limit.

If the tonneau cover 30 is able to extend over the luggage without obstruction, then it is clear that the roof structure, should it be folded, will not be obstructed either. However, if the tonneau cover 30 is not able to be extended over the luggage without obstruction, then it is likely that the roof structure will be impeded by the luggage from moving to its fully folded position, therefore requiring repositioning or adjustment of the luggage in the luggage compartment 18b. Full extension of the tonneau cover 30 is detected by a switch 34 which is connected to a control unit for controlling the movement of the roof mechanism.

Such tonneau covers present a number of disadvantages. Firstly, they are relatively expensive to implement on a vehicle and it would be preferable to provide a system which is less costly. Secondly, being mechanical components which are manually operated on a relatively frequent basis, they wear rapidly and are prone to develop a worn and unsightly appearance. Thirdly, they are heavy and add to the sprung weight of the vehicle. Finally, the cover is required to be operated before the vehicle is used and potentially some time before the roof structure is required to be folded. It is possible, during normal driving manoeuvres, for luggage in the luggage compartment to shift such that, notwithstanding the presence of the extended tonneau cover 30, it protrudes above the predetermined limit to a height at which it can interfere with the movement of the roof structure 10 as described above.

In response to these and other disadvantages of the tonneau cover system, the present applicants have developed an improved system which alleviates or reduces some or all of these problems.

Referring to Figure 4, a first form of system according to the invention is shown generally at 100. The system comprises transmitter means, in the form of a plurality of electromagnetic transmitters 102, disposed in or on one wall of the luggage compartment 18b of the vehicle. The transmitters are positioned at a height corresponding substantially to the predetermined height limit, in other words at the maximum luggage height which can be permitted within the luggage compartment without interfering with the movement of the roof structure. In practice, therefore, the transmitters will be positioned at substantially the same height within the luggage compartment 18b as the prior art tonneau cover 30 would be.

Receiver means, in the form of a corresponding plurality of electromagnetic receivers 104, is disposed in or on an opposing wall of the luggage compartment at a height corresponding to the height of the transmitter means.

Both the transmitter means 102 and the receiver means 104 are connected to control means in the form of a control unit or processor 106. The control unit 106 is also connected, at an input thereof, to switch means in the form of a mechanical switch 108. The switch 108 is manually operable by the user to initiate folding of the roof structure 10. The control unit 106 is additionally connected, at an output thereof, to a motor 110 of a positive drive mechanism for causing movement of the roof structure 30 between the first and second positions and to indicator means 112, the purpose of which is described below.

In the illustrated embodiment, the transmitter means comprises a plurality of optical transmitters 102, such as infra-red (JR) emitters or diodes. Each diode 102 is arranged to transmit, under control of the control unit 106, an optical signal S which may be either substantially uni-dimensional, i.e. a pinpoint beam, or two-dimensional, such as a parallel beam or a fan- shaped beam. In the illustrated embodiment, the optical signal S is a parallel beam which does not diverge from the transmitter. In one embodiment, the transmitted beam is threedimensional, such as a conical beam, since this arrangement is able to compensate for any misalignment through, for example, build discrepancies or body flexing.

The receiver means 104 comprises one or more optical receivers 104 such as photodiodes, light dependent resistors (LDRs) or charge coupled devices (CCDs) which are arranged to sense or detect the optical signals generated by the transmitter means 102.

In use, if the user wishes to move the roof structure from its first, nonfolded position to its second, folded position in order to open the vehicle cabin, he/she manually operates the switch 108. Operation of the switch 108 in this manner is detected by the control unit 106 which generates a TRANSMIT signal and applies this signal to the transmitters 102. In response to the TRANSMIT signal from the control unit 106, the transmitters 102 generate an optical signal, in the manner described above, and transmit it across the luggage compartment 18b, at the predetermined height h, to the receiver means 104.

If there is no luggage in the luggage compartment 18b which extends above the predetermined height h, then the receivers 104 will receive the full optical signal from the transmitter means. On receipt of the optical signal, the receiver generate a RECEIVED signal which is applied to the control unit 106.

In response to the RECEIVED signal being received by the control unit 106, the latter generates an OPERATE signal which is applied to the motor 110 or other drive means of the positive drive mechanism for the roof structure 10.

The positive drive mechanism 110 then moves the roof structure, in a conventional manner, between the first and second positions.

If, however, there is luggage in the luggage compartment 18b which exceeds the predetermined height, and hence will interfere with the roof structure 10, the optical signal S from the transmitters 102 will be partly blocked by the offending luggage such that the receivers 104 will not receive all of the optical signal, as illustrated in Figure 4. For example, where there are a plurality of optical receiving devices 104 such as photo diodes, one or more of the diodes may not receive the optical signal from the transmitter means 102.

If all or part of the optical signal S is not received, in the manner described above, then the receivers 104 generate a NOT RECEIVED signal which is applied to the control unit 106. On receipt of the NOT RECEIVED signal, the control unit 106 does not generate the OPERATE signal but instead generates an ERROR signal. The ERROR signal is applied to the indicator means 112 which generates an audible or visual alert signal to the user to indicate that there is obstructing luggage in the luggage compartment. In this instance, the motor 110 or other drive means for the positive drive mechanism does not operate to move the roof structure.

Figure S is a flow diagram illustrating the steps involved in the method of the present invention and the operation of the system of the present invention. In i Step 1, the user operates the switch 108 to select movement of the roof structure 10 from the first, non-folded position to the second, folded position.

In step 2, the control unit 106 generates a TRANSMIT signal which is applied i to the transmitters 102. In step 3, the transmitters generate an optical signal which is transmitted across at least a portion of the roof storage compartment 18a and/or the luggage compartment 18b.

If the optical signal is fully received by the receivers 104, these generate a RECEIVED signal which is applied to the control unit 106 (Step 4a). On receipt of the RECEIVED signal, the control unit 106 generates an OPERATE signal which is applied to the motor 110 or other drive means (Step Sa). The motor 110 then operates to move the roof structure between the first and second positions (Step 6a) Alternatively, if the optical signal is not fully received by the receivers (i.e. it is only partially received or it is not received at all), the receivers 104 generate a NOT RECEIVED signal which is applied to the control unit 106 (Step 4b). On receipt of the NOT RECEIVED signal, the control unit 106 generates an ERROR signal which is applied to the indicator means 112. No OPERATE signal is generated (Step Sb). The indicator means then generates an audible, visual, tactile or other alert signal to alert the user that there is luggage protruding into the roof storage compartment 18a.

It will be appreciated that the present invention provides a simple and effective system and method for detecting the presence of luggage within the luggage i compartment of a vehicle which could interfere with the folding mechanism for the vehicle roof and hence cause damage thereto. The system, which effectively uses a "light curtain" to detect luggage impinging into the roof storage compartment, is significantly less expensive to provide on a vehicle compared with existing systems and has the additional advantage that the height of the luggage is checked for possible interference immediately before the roof structure is moved, thereby taking into account any movement of the luggage due to vehicle movement since the position of the luggage was last checked.

In addition, the process of checking for obstructing objects within the luggage compartment/roof storage compartment can be repeated to monitor substantially continuously throughout the movement of the roof structure. For example, after operation of the switch 108, the control unit 106 may repeatedly send the TRANSMIT signal to the transmitter unit 102 during the period when the roof structure is in motion. If, at any time during that period, the receiver unit generates the NOT RECEIVED signal or, indeed, anything other than the RECEIVED signal, the control unit 106 generates a STOP signal which is applied to the drive mechanism 110. In response to the STOP signal, the drive mechanism stops moving the roof structure and, optionally, reverses the movement to return the roof structure to the first, non-folded position.

It will be understood that a number of variations or improvements could be made to the invention. For example, the sequence of operation of the system and subsequent movement of the roof structure 10 need only be initiated in respect of movement of the roof structure from the first, non-folded to the second, folded position. No such procedure is required in respect of movement from the second, folded position to the first, nonfolded position since there is no danger of obstruction from the luggage, the roof structure 10 already being in its second, folded position.

In addition, means could be provided to enable the user to check, prior to operation of the vehicle, whether any luggage exceeds the predetermined height limit, thereby giving the user opportunity to adjust or reposition luggage to avoid interference with the roof structure. This could be achieved by the provision of an additional switch (not shown) located in the luggage compartment and connected to the control unit which, when actuated, causes the system to operate in the manner described above with the exception that, if no part of the luggage exceeds the predetermined height, so that the RECEIVED signal is generated by the receiver means, the control unit does not generate the OPERATE signal for the motor. If any part of the luggage does exceed the predetermined height, the ERROR signal is generated and the indicator means generates the audible or visual signal to indicate to the user that a potential obstruction is present.

The illustrated embodiment employs a plurality of transmitters and receivers to transmit and receive the optical signals. It will be appreciated, however, that only one transmitter and one receiver may be effectively used. In order that substantially all of the cross-sectional area of the luggage compartment is checked for obstructions, the transmitter and receiver could be mounted on carriages which are arranged to travel in unison along the length or width of the luggage compartment, for example in the manner of a conventional scanner. If at any point during the "scan" the receiver fails to receive the optical signal from the transmitter, this indicates that there is obstructing luggage which could interfere with the roof structure.

More than one "scan" could be initiated following actuation of the switch 108 as a failsafe measure and to improve system accuracy. For example, in the embodiment described above, the system is arranged to scan the luggage compartment/roof storage compartment for obstructions only once, following operation of the switch 108 and prior to movement of the roof between the first and second positions. If the system determines that there are no obstructions present, in the manner described, then the control unit 106generates the OPERATE signal to cause the roof structure to move between the first and second positions. However, if the system determines that an obstruction is present, then the control unit 106 generates the ERROR signal and the roof structure is not moved at all.

On the other hand, in some circumstances it may be desirable to scan repeatedly, even during movement of the roof structure between the first and second positions. In this case, the system scans the luggage compartment/roof storage compartment when the user operates the switch 108, in the manner described above. If the system determines that there are no obstructions present then the control unit 106 generates the OPERATE signal to cause the roof structure to move between the first and second positions. While the roof structure is in motion, the system scans the luggage compartment/roof storage compartment again. This enables the system to determine whether any luggage has shifted in such a way as to present an obstruction whilst the roof is moving.

This is particularly advantageous where the roof system permits retraction of the roof structure whilst the vehicle is in motion since movement of the luggage in the luggage compartment/roof storage compartment may occur after the initial scan has been performed. Several scans may be performed during movement of the roof structure.

In the event that the system detects an obstruction during movement of the roof structure, the control unit may be arranged to generate the STOP signal or the ERROR signal and movement of the roof structure is halted or the roof structure is returned to the first, closed position.

Alternatively, a plurality of transmitters/receivers could be employed but in a different arrangement from that illustrated in Figure 4. For example, to ensure that substantially all of the cross sectional area of the luggage compartment/roof storage compartment is scanned, transmitters 612 and receivers 614 can be alternately positioned along opposing side or end walls of the luggage compartment. In this way, all areas of the luggage compartment/roof storage compartment are scanned with substantially no breaks in coverage. Additionally or alternatively, optical guides and/or mirrors could be employed.

It may be desirable to include means for compensating for noise caused by ambient light which is incident on the receiver means when the trunk lid 19 is s opened. The provision of such noise compensating means may be advantageous in the embodiment where the system repeatedly or continuously scans for obstructions while the roof structure is moving between the first and second positions. During movement of the roof structure, the trunk lid will necessarily be in the open position, allowing significant ambient light to enter the roof storage compartment. This ambient light can adversely affect the performance of the receiver means 104, potentially leading to failure of the system.

This noise "filtering" may be effectively achieved by modulating the optical signal between on and off states and determining the difference between the received signal level when the transmitted signal is on and the received signal level when the transmitted signal is off. This can be further enhanced by repeating the process a number (x) of times and calculating, for example, s x Ruc(off) - Rx(on). It will be understood that the variables in this equation 0 0 may be reversed.

If the magnitude of this difference exceeds a predetermined threshold level, the system assumes that the optical signal is substantially fully received and that there are therefore no obstructions in the luggage compartment/roof storage compartment. If the magnitude of the difference does not exceed the predetermined level, then the system determines that an obstruction is present.

The predetermined level can be set as desired but may be established empirically. This "filtering" process can readily be carried out by the control unit 106.

While the invention described herein has been described with reference only to a hard-top cabriolet vehicle, it will be understood that the invention finds application with any vehicle having a folding roof structure which, in the folded position, is located within a roof storage compartment.

In addition, the use of the terms TRANSMIT signal, RECEIVED signal, NOT_RECEIVED signal, OPERATE signal, ERROR signal and STOP signal are representative of functional signals only and are not intended to be limiting in any way.

It will be understood that the embodiments described above are give by way of example only and are not intended to limit the invention, the scope of which is defined in the appended claims. It will also be understood that the embodiments described may be used individually or in combination.

Claims (18)

1. A detection system for an automobile having a folding roof structure arranged to be moved between a first, non-folded position in which the roof structure substantially covers the passenger compartment of the vehicle and a second, folded position in which the roof structure is stored in a storage compartment of said vehicle, wherein the system comprises transmitter means for generating and transmitting a signal across at least a portion of said storage compartment, receiver means for receiving said signal and control means for controlling the movement of the roof structure in dependence thereon.

2. A system as claimed in claim 1 wherein the signal is an electromagnetic signal and wherein the control means is adapted to substantially prevent movement of the roof structure if the electromagnetic signal is not fully received by the receiver means.

3. A system as claimed in claim 2 further comprising switch means for actuating the system.

4. A system as claimed in claim 3 wherein the control means is arranged to apply a TRANSMIT signal to the transmitter means in response to operation of the switch means.

5. A system as claimed in claim 4 wherein the transmitter means is operable to transmit the electromagnetic signal in response to the TRANSMIT signal.

6. A system as claimed in claim 5 wherein the receiver means is arranged to generate a RECEIVED signal on receiving the electromagnetic signal and to apply the RECEIVED signal to the control means.

7. A system as claimed in claim 6 wherein the control means is arranged to generate a OPERATE signal and to apply the third signal to a motor or other drive means, thereby to move the roof structure between the first and second positions.

8. A system as claimed in claim 7 wherein the receiver means is arranged to generate a NOT RECEIVED signal if the electromagnetic signal is not received or is only partially received, the NOT RECEIVED signal being applied to the control means.

9. A system as claimed in claim 8 further comprising indicator means for generating an audible, visual, tactile or other alert signal to alert the user of the vehicle.

A system as claimed in claim 9 wherein the control means is arranged to generate an ERROR signal on receipt of said NOT RECEIVED signal and to apply the ERROR signal to the indicator means, the indicator means being arranged to generate the alert signal on receipt of the ERROR signal.

11. A system as claimed in claim 9 or claim 10 wherein on receipt of the NOT RECEIVED signal, the control means does not generate the OPERATE signal such that the roof structure is not moved between the first and second positions.

12. A system as claimed in claim 9 or claim 10 wherein on receipt of the NOT RECEIVED signal, the control means applies the ERROR signal to the motor or drive means such that the roof structure is not moved between the first and second positions.

13. A system as claimed in any of claims 4 to 12 wherein the control means is arranged to generate the TRANSMIT signal repeatedly or substantially continuously following generation of the OPERATE signal.

14. A system as claimed in any of claims 2 to 13 wherein the electromagnetic signal is an optical signal and the transmitter means comprises one or more optical transmitters.

15. A system as claimed in any of claims 2 to 14 wherein the electromagnetic signal is an infrared signal and the transmitter means and the receiver means are arranged to transmit and receive, respectively, the infrared signal.

16. A system as claimed in claim 14 or claim 15 further comprising means for compensating for electromagnetic noise caused by ambient light.

17. A system as claimed in any preceding claim wherein one or both of the transmitter means and the receiver means is movable within the storage compartment.

18. A method of detecting an object within a roof storage compartment of a vehicle having a folding roof structure, the method comprising generating and transmitting a signal across at least a portion of said roof storage compartment, monitoring whether said signal is received and substantially preventing the operation of said roof structure in dependence thereon.