Storage Compartment Sensor System for Use With an Automotive Vehicle Convertible Roof

This invention relates generally to automotive vehicles having convertible roofs and specifically to a sensor system for detecting undesired objects in a convertible roof storage compartment.

Convertible roofs are commonly provided on many automotive vehicles. These convertible roofs are movable from a raised position attached to a front windshield header to a lowered or stowed position within a storage compartment. Traditionally, the storage compartment is located within a trunk space which is accessible by opening a trunk or deck lid about a rear pivot. The storage space is alternately between a rearmost passenger seat and a trunk, and is often called a boot.

Conventional convertible roofs include both hard-top and soft-top constructions. Examples of such conventional hard-top systems are disclosed within the following U.S. patents: U.S. Pat. No. 5,195,798 entitled "Retractable Roof for Vehicles" which issued to Klein et al. on Mar. 23, 1993; U.S. Pat. No. 4,854,634 entitled "Upper Body Structure for a Convertible Vehicle" which issued to Shiraishi et al. on Aug. 8, 1989; U.S. Pat. No. 2,939,742 entitled "Foldable Vehicle Top" which issued to Dardarian et al. on Jun. 7, 1960; U.S. Pat. No. 2,704,225 entitled "Convertible Automobile Top" which issued to Anschuetz et al. on Mar. 15, 1955; and, U.S. Pat. No. 2,007,873 entitled "Vehicle Body Top Capable of Being Stowed Away" which issued to Paulin on Jul. 9, 1935. Examples of conventional soft-top convertible roofs include U.S. Pat. No. 4,720,133 entitled "Convertible Top Structure" which issued to Alexander et al. on Jan. 19, 1988; and, U.S. Pat. No. 4,958,882 entitled "Folding Top for Vehicles" which issued to Kolb on Sep. 25, 1990. The disclosures of all the afore-mentioned conventional convertible roof patents are incorporated by reference herewithin.

Objects left in the trunk or boot storage compartments can cause a severe problem upon retraction of these convertible roofs. A jack, briefcase or even an object as small as a golf ball can break a glass backlite and bend linkages when inadvertently pressed thereagainst. The likelihood of such an event is further heightened with the ever increasing use of electric motors to automatically drive the convertible top-stack linkages.

Unrelated to convertible roofs, occupant sensors have been used in seat belt systems for a number of years. Examples of such a seat occupant sensor are disclosed within the following U.S. patents: U.S. Pat. No. 4,107,645 entitled "Seat Belt System with Starter Engine Lock and Alarm" which issued to Lewis et al. on Aug. 15, 1978; U.S. Pat. No. 3,859,485 entitled "Occupant Sensor Seat Switch" which issued to Blinkilde et al. on Jan. 7, 1975; U.S. Pat. No. 3,845,261 entitled "Occupant Sensor Seat Switch with Deformable Conductive Spacer Pads" which issued to Blinkilde on Oct. 29, 1974; U.S. Pat. No. 3,761,658 entitled "Load Responsive Switch" which issued to Loose et al. on Sep. 25, 1973; and, U.S. Pat. No. 3,715,541 entitled "Cushion Seat Switch Sensor Means" which issued to Koenig on Feb. 6, 1973; the disclosures of which are all incorporated by reference herewithin. While seat sensors have proven effective in detecting a person occupying a seat, these conventional sensors have not been employed in combination with a convertible roof for preventing inadvertent destruction thereof upon retraction.

In accordance with the present invention, a preferred embodiment of a sensor system is located in a storage compartment of an automotive vehicle for preventing full retraction of a convertible roof when an undesired object is detected within the storage compartment. In one aspect of the present invention, a sensor employs a pair of nominally separated conductive layers. This sensor construction transmits an electrical signal when the weight of an undesired object places the conductive layers in electrical contact or moved toward each other. A further aspect of the present invention provides a sensor system capable of transmitting and receiving waves. In another aspect of the present invention, an electric roof motor is controlled by an electrical control unit which operates the motor responsive to a signal transmitted by a sensor coupled thereto. In yet another aspect of the present invention, a method of using and a method of retrofitting an automotive vehicle with a convertible roof and an object sensor system is provided.

The sensor system of the present invention is advantageous over traditional systems. For example, a sensor of the present invention prevents inadvertent damage to a convertible roof upon retraction thereof. Furthermore, a sensor of the present invention can detect objects as small and light weight as a golf ball. The present invention sensor system is also advantageous in that it takes up a minimal amount of packaging space within a storage compartment. Moreover, the present invention sensor system controls an electromagnetic device through an electrical control unit. Additional advantages and features of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings.

FIG. 1 is a perspective view showing a preferred embodiment of a sensor of the present invention;

FIG. 2 is an exploded perspective view showing a preferred embodiment sensor system of the present invention employing the sensor of FIG. 1;

FIG. 3 is a sectional view, taken along line 3--3 of FIG. 1, showing the preferred embodiment sensor system of the present invention;

FIG. 4 is a side elevational view showing the preferred embodiment sensor system employed in a preferred embodiment automotive vehicle of the present invention;

FIG. 5 is a side elevational view of a preferred embodiment convertible roof of FIG. 4, shown in a raised position;

FIG. 6 is a side elevational view of the preferred embodiment convertible roof of FIG. 4, shown in a fully retracted position;

FIG. 7 is a perspective view showing an alternate embodiment sensor system employed in an alternate embodiment automotive vehicle of the present invention;

FIG. 8 is a perspective view showing a second alternate embodiment sensor system employed in a second alternate embodiment automotive vehicle of the present invention;

FIG. 9 is an electrical schematic diagram showing the preferred embodiment sensor system of the present invention employing the sensor of FIG. 1;

FIG. 10 is a top elevational view showing leads extending from the preferred embodiment sensor of the present invention of FIG. 1;

FIG. 11 is an electrical schematic diagram showing the electrical operation of the preferred embodiment sensor of the present invention of FIG. 1;

FIG. 12 is a diagrammatic flow chart showing the interaction of a microprocessor of the preferred embodiment sensor system of the present invention employing the sensor of FIG. 1; and

FIG. 13 is a fragmentary top diagrammatic view showing a third alternate embodiment sensor of the present invention within a trunk of an automotive vehicle.

In accordance with the present invention, the preferred embodiment of a storage compartment sensor system is employed in an automotive vehicle having a convertible roof. In this preferred embodiment, the convertible roof is a two-part hard-top roof variety which is operated by a linkage and electric motor system. The present invention sensor system prevents full retraction of the convertible roof into a storage compartment when a sensor detects an undesired object located therein. This prevents inadvertent damage to the convertible roof upon retraction. The undesired object can be defined as any non-vehicle object remaining in the storage compartment prior to roof retraction. The sensor system includes a sensor, materials covering and supporting the sensor, an electrical control unit and an electrical circuit interacting therewith.

Referring to FIGS. 1-4, a preferred embodiment sensor 21 consists of an upper mylar sheet 23 having an electrical conductor 25 silkscreened or otherwise printed on the inside thereof, a lower mylar sheet 27 having an electrical conductor 29 silkscreened or otherwise printed on a top surface thereof, and a soft rubber substantially nonconductive material 31 silkscreened or placed on top of conductor 29 and mylar sheet 27. Mylar sheets 23 and 27 are generally flexible such that when they are adhered together upper conductor 25 can be depressed through voids 33 within nonconductive material 31 so as to electrically contact lower conductor 29. Upper and lower conductors 25 and 29, respectively, are made from a highly conductive noncorrosive material such as a tin and silver alloy.

Sensor 21 must operate on an automotive input voltage between 8 and 24 volts, dc, and be capable of switching a minimum amperage of 25 ma. The sensor is capable of detecting a 3.6 ounce minimum actuation force or weight necessary to cause electrical contact between the conductors. This simulates a golf ball sized and weighted object. The conductive layers must have a maximum contact resistance of 50 ohms with an open resistance greater than 10.sup.6 ohms. Sensor 21 must operate within a temperature range of -40.degree. Celsius to 85.degree. Celsius and having a cycling life greater than 20,000 cycles. Such a sensor can be purchased from The Hall Co. of Urbana, Ohio.

Lower mylar sheet 27 is adhered or otherwise bonded to a hard masonite floor board 35 which is positioned against a floor 37 of a storage compartment 39. In this embodiment, storage compartment 39 is defined as the trunk area of the automotive vehicle. In a general sense, a seat back panel 41 separates trunk 39 from a passenger compartment 43. Of course, the storage compartment may take the form of any area where the convertible roof can be stowed. A pressure point enhancement layer 51 is made from a mylar or polycarbonate type material having pressure enhancement contours such as bumps 53 formed or molded therein. Pressure point enhancement layer 51 is juxtapositioned on top of upper mylar sheet 23 such that bumps 53 are preferably aligned with conductors 25 and 29. Pressure point enhancement layer 51 serves to localize pressures and multiply the effective weight of a flat object such that sensor 21 can detect the weight thereof. Pressure point enhancement layer 51 is adhered or otherwise bonded to sensor 21 as is a carpet 61 aesthetically mounted thereabove.

A preferred embodiment convertible roof 81 is shown in FIGS. 4-6. Convertible roof 81 includes an entirely rigid front roof section 83 and an entirely rigid rear roof section 85 containing a glass backlite 87 and retractable quarter window (not shown). A linkage assembly 91 and a fractional horsepower dc electric motor 93 serve to lift and rotate convertible roof 81 from a raised position (FIG. 5) to a fully retracted position (FIG. 6). Rear roof section 85 is pivotably inverted and front roof section 83 is folded in a clamshell manner about a hinge 95 when convertible roof 81 is fully retracted. A decklid panel 101 containing a pair of collapsible and extensible flippers or extension members 103 pivots about a rear tail panel of the automotive vehicle and serves to act as a tonneau cover against convertible roof 81. Sensor 21 is disposed along floor 37 of trunk 39 so as to detect an undesired object 111 such as golf clubs, spare tires, brief cases, golf balls, or the like. Other preferred embodiment convertible roofs may be driven by more conventional motor operated hydraulic pump and linkage mechanisms.

A first alternate embodiment sensor system and convertible roof is shown in FIG. 7. In this embodiment, a sensor 121 of the type employed with the preferred embodiment, is disposed within a rear seat 123. A convertible roof 125, here shown as a conventional soft-top roof is retractable into a storage space 127 defined at least in part above rear seat 123. A variation of the embodiment folds a substantially vertical back portion of rear seat 123 horizontally forward with sensor 121 positioned on the uppermost folded surface thereof. For this application, the preferred sensor heretofore discussed is advantageous over traditional seat belt occupancy detectors since the present invention employs a sensor capable of detecting a golf ball sized and weighted object which could damage a convertible roof.

A second alternate embodiment sensor system and convertible roof is illustrated in FIG. 8. In this embodiment, a soft-top convertible roof 131 is retractable into a storage compartment 133 located rearward of a rearmost seat 135 but forward of a trunk 137. A sensor 139 is positioned within storage compartment 133 along its floor and even possibly along its vertical walls.

Other alternate embodiments employ different types of sensors within the storage compartment. Referencing FIG. 13, a proximity, ultrasonic, infrared, optical or magnetic sensor 201 is positioned within a trunk 203 rearward of a seatback panel 41. These otherwise conventional sensors transmit a magnetic wave field, sound wave or light wave beam which, normally bounces off of the vehicle panels such as the tail, quarter and floor pan panels. The wave is received or detected by sensor 201 which utilizes an electrical control unit to calculate its magnetic value, return time, distance, or integrity. It may be desirable to further rotate sensor 201 from side-to-side within trunk 203. The electrical control unit is provided with a different signal when the wave received by sensor 201 is interrupted or changed from the nominal value by an undesired object in its path. A separately located wave receiver can also be employed.

A further alternate embodiment sensor uses a capacitive sensor which appears similar to the sensor illustrated in FIGS. 1-3. However, this alternate sensor can be more sensitive than the preferred embodiment. With the present embodiment, an electrical control unit measures and compares the capacitive distance or gap between conductive layers before and during depression by an undesired object. Depression moves at least one of the conductive layers toward the other. Full electrical contact between conductive layers is not necessary. However, barometric pressure and temperature variations must be accounted for.

Referring again to the preferred embodiment system of FIGS. 9-11, an electrical control unit such as a microprocessor 161 is electrically coupled to sensor 21 through electrical connectors 163 and 165. Among other functions, microprocessor 161 serves to control roof motors 93 as a function of a driver operated switch, position sensing potentiometers, sensor 21 and other optional features. An example of such a driver operated button is disclosed within U.S. Pat. No. 5,225,747 entitled "Single-Button Actuated Self-Correcting Automatic Convertible Top" which issued to Helms et al. on Jul. 6, 1993, the disclosure of which is incorporated by reference herewithin. Electrical control unit 161 may alternately take the form of a Field Effect Transistor, an Isolated Gate Bata Transistor or a Bipolar.

A lead 167 extends from sensor 21 to connector 163. Lead 167 contains a first pin 169, a second pin 171 and a third pin 173. First and second pins, respectively 169 and 171, are electrically coupled to one another for providing a constant path current or short-type situation to send a signal which informs microprocessor 161 if sensor 21 is connected thereto. When an object is detected upon sensor 21, upper conductor 25 electrically contacts with lower conductor 29. This operates as a normally open single pole, single throw switch 175 which, in turn, provides a signal to microprocessor 161.

The interaction between the sensor, microprocessor and roof motors is diagrammatically shown in FIG. 12. If the undesired object is not detected by the sensor then the convertible roof is allowed to be fully retracted into the storage compartment. If the object is detected by the sensor when the convertible roof is between the raised position and an approximately half raised position then the convertible roof is retracted to the approximately half raised position and then the motors and retraction are stopped. If the sensor is not electrically coupled to the microprocessor then the microprocessor will act as if an object were detected within the storage compartment. If the object is detected when the convertible roof is between the generally half raised position then the motors and retracting movement is reversed such that the convertible roof is stopped in the substantially half raised position; this allows the vehicle occupant to remove the undesired object and reactuate the driver operated button. If the weight of the undesired object is too light to be detected, then the convertible roof will retract until a portion of the roof lightly presses the object into the sensor at a force which can be detected; at this point, the motors and retracting movement of the convertible roof is reversed and stopped at the substantially half raised position.

While various embodiments of the sensor system and convertible roofs have been disclosed, it will be appreciated that various modifications may be made without departing from the present invention. For example, the membrane switches of U.S. Pat. Nos. 4,515,999 which issued to Harper; 4,489,302 which issued to Eventoff; and 4,423,294 which issued to Walser et al., can also be employed herewith, and the disclosures of which are incorporated by reference herewithin. Conventional piezo-electric, electrochemical, resilient and electrically conductive pads, and even copper stampings with spacers or springs therebetween can be employed within the present invention sensor system. Magnetic, optical, infrared, ultrasonic, pressure, capacitive, doppler and proximity sensors, known within the art, can also be interchangeably used within the present invention system. Furthermore, a variety of other convertible roofs, linkage mechanisms and tonneau covers can be incorporated in combination With the present invention sensor system. The present invention further encompasses a sensor used to move or otherwise operate an electromagnetic device, such as a solenoid, to block or prevent full retraction of a manual or powered convertible roof. Of course, a normally closed switch sensor which send a signal upon or during opening is considered as part of the present invention system. Various materials have been disclosed in an exemplary fashion, however, various other materials may of course be employed. It is intended by the following claims to cover these and any other departures from the disclosed embodiments which fall within the true spirit of this invention.