SAFETY INTERLOCK FOR MECHANICALLY ACTUATED CLOSURE DEVICE

Abstract: An object detection system employs an optical triangulation module for detecting the presence of an object within a pinch zone of an automated closure device such as a power sunroof (22), power window, powered door of powered hatch. The optical triangulation module includes an emitter (160) and a position sensitive detector (166).

Description: TITLE OF THE INVENTION Safety Interlock for Mechanically Actuated Closure Device CROSS REFERENCE TO RELATED APPLICATIONS Not Applicable STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT Not Applicable BACKGROUND OF THE INVENTION The present invention relates to safety interlocks and more particularly to a method and apparatus for providing an indication of the presence of an object within a pinch zone located in the vicinity of an automated closure device such as a powered window, powered sunroof, powered door or hatch. Closures for apertures such as vehicle windows, sunroofs and sliding doors are now commonly motor driven. As a convenience to an operator or passenger of a vehicle, power windows are frequently provided with control features for the automatic closing and opening of an aperture following a simple, short command from the operator or passenger. Alternatively, automatic closing and opening of an aperture may be in response to input from a separate device, such as a rain or temperature sensor. For instance, a driver' s side window may be commanded to rise from any lowered position to a completely closed position simply by momentarily elevating a portion of a window control switch, then releasing the switch. This is sometimes referred to as an w express close" feature. This feature is also commonly provided in conjunction with vehicle sunroofs. Auto anufacturers may also provide these features in conjunction with power doors, hatches or the like. Such automated aperture closing features may also be utilized in various other home or industrial settings . In addition to providing added convenience, however, such features introduce a previously un-encountered safety hazard. Body parts or inanimate objects may be present within an aperture when a command is given to automatically close the aperture. For example, an automatic window -closing feature. may be activated due to rain impinging on an interconnected rain sensor while a pet in the vehicle has its head outside the window. A further example includes a child who has placed its head through a window or sunroof which is activated to close by the driver, another passenger or accidentally by the child. In order to avoid potentially tragic accidents or property damage involving intervening objects entrapped by power windows or sunroofs, systems have been developed which detect the circumstance in which a window has been commanded to express close but closure has not occurred within a given period of time. As an example, a system may monitor the time it takes for a window to reach a closed state. If a temporal threshold is exceeded, the window is automatically lowered. Another system monitors the current drain attributed to the motor driving the window. If it exceeds a threshold at an inappropriate time during the closing operation, the window is again lowered. The problem with such safety systems is that an intervening object must first be entrapped and subject to the closing force of the window or other closure device for a discrete period of time before the safety mechanism lowers the window or reverses the sunroof or other closure device. Personal injury or damage to property may still occur in such systems. In addition, if a mechanical failure in the window driving system occurs or if a fuse is blown, the person or object may remain entrapped. Non-contacting object detection systems are known which detect the presence of an intervening object within an aperture area. Such systems are employed, for example, with security systems and garage door safety interlocks, to detect interruption of a light beam across an opening. Other systems are used with automotive apertures having motorized closure members such as windows, sunroofs, and sliding doors, to detect an intervening object proximate or extending through the respective aperture. Undesired operation of an aperture closure member is therefore prevented when an intervening object such as a finger or arm is extended through the aperture during closure; the closure member is not required to come into contact with the intervening object for the object to be detected. Such object detection systems typically measure the magnitude of a reflected signal to determine the presence or non-presence of an intervening object. An emitter emits a light beam which is directed across the aperture towards an opposing side of the aperture. An uninterrupted aperture results in the reflection of at least a portion of the emitted beam from the opposing side of the aperture. A receiver disposed near the emitter receives the reflected light beam and generates an output signal indicative of the intensity of the reflected beam. Reflection from the opposing side ordinarily results in a reflected signal of a nominal intensity being returned to the receiver. An intervening object located in the path of the light beam changes the intensity of the reflected light beam, a condition reflected in the detector output signal . The detector output signal with an object in the light beam path will thus differ from the detector output signal in the absence of an object. Depending upon the reflectivity of the intervening object and the reflectance characteristics of the aperture environment, the detector output signal will • be greater or less than the nominal output signal from the detector. Distance measuring triangulation sensors are known which are employed to generate an output signal representative of the distance to an object. Such sensors include, for example, Model Nos. GP2D02 and GP2D05 distance measuring sensors commercially available from Sharp Microelectronics of the Americas, Camas, Washington USA. Such sensors, which are referred to herein as optical triangulation modules, include an emitter and an adjacent detector mounted in a common package. The detector employed in such a module is referred to as a position sensitive detector (PSD) which provides a .signal indicative of the location on the surface of the detector at which a reflected beam strikes the PSD surface. The module is typically positioned such that the emitter emits a light beam in the direction of a target object. The light beam is reflected off the target object so as to impinge on the surface of the PSD. Since the distance between the emitter and the detector are fixed, the distance to the target object can be determined via triangulation techniques based upon the output signal obtained from the PSD. When the target object is closer to the module, the light beam emitted by the emitter and reflected off the object will impinge upon the PSD farther away from the emitter. Optical triangulation modules have heretofore been employed for the detection of distances between the module and a target object such as in focal systems within cameras. It would therefore be beneficial to provide a safety interlock that is capable of detecting the presence of an object in a pinch zone adjacent an automated closure device so as to prevent a moving member from causing injury or damage to person or property. BRIEF SUMMARY OF THE INVENTION A method and apparatus is disclosed for providing a signal indicative of the presence of an object within a pinch zone. The definition of the pinch zone varies depending upon the nature of the automated closure device. For example, if the automated closure device comprises a power assisted, slidable closure member such as power sunroof, a power window or a powered door, the pinch zone is defined by a leading edge of a closure member and a portion of the aperture defining a terminal portion of the aperture opening with the closure member leading edge. If the closure device comprises a powered, hinged door or hatch or a powered revolving door, the pinch zone is generally a plane defined by an edge of the aperture approached by the leading edge of the door or hatch and a line adjacent the aperture edge in the path of travel of the leading edge of the door or hatch. In one embodiment in which the closure member comprises a slidable closure member, an optical triangulation module having an emitter and a position sensitive detector (PSD) is selectively positioned adjacent the plane of slidable movement of the closure member such that the emitter of the module emits an infrared (IR) beam which passes through the pinch zone and reflects from a reflective surface on the opposing side of the pinch zone to the PSD within the module. The IR light beam impinges on the surface of the PSD at a nominal position in the absence of an object within •the pinch zone.. In the event an object is present within the pinch zone within the path of the emitted IR beam, the IR beam is reflected off the object to a different position on the PSD. The PSD provides an output signal which is analyzed to provide an indication of the presence of an object within the pinch zone. The output signal may be employed to halt the movement of the powered closure member, reverse the movement of the powered closure member, activate an alarm or some combination of these. In another embodiment, the optical triangulation module is positioned adjacent the pinch zone of a powered hatch, powered hinged door or revolving door. More specifically, the module is selectively positioned such that the emitter emits an IR light beam which passes through the pinch zone and, as discussed above, in the absence of an object within the pinch zone, reflects from a reflective surface on the opposing side of the pinch zone to a nominal location on the surface of the PSD in the absence of an object within the pinch zone. In the event of the presence of an object within the pinch zone, the light beam emitted by the module emitter is reflected off the object to a different position on the surface of the PSD. In response to the detection of the difference in the PSD output signal, the movement of the powered door or hatch, as applicable may be halted or reversed. Additionally, to provide greater reliability in the detection of objects within the pinch zones of the automated closure devices discussed above, an IR reflected amplitude detection system may be employed in combination with the optical triangulation module. The IR reflected amplitude detection system includes an IR emitter and an IR amplitude detector positioned adjacent the emitter and preferably in a common housing. In one embodiment, the IR reflected amplitude detection system shares a common housing with the optical triangulation module. The IR emitter emits a substantially planar light beam which, in the absence of an object within the pinch zone, is reflected from one or more reflective surfaces on the opposing side of the pinch zone and back to the IR amplitude detector. In the event an object intrudes on the path of the light beam emitted by the IR emitter, a change in the amplitude of the received IR light beam is detected by the IR amplitude detector. The output of the IR amplitude detector is analyzed or subject to thresholding to provide an indication of the presence of an object within the pinch zone. As a result of the detection of the presence of an object within the pinch zone by either the IR amplitude detector or the PSD, or both, the movement of the powered closure member may be halted or reversed, and/or an alarm may be generated. The presently disclosed system can also be employed for intrusion detection. For instance, if the closure is a powered window and automatic venting is enabled while the ' vehicle is parked, it may be possible for someone to attempt unauthorized entry into the vehicle through the partially lowered vehicle, or to insert an object through the opened window for the purpose of disengaging a door lock. Monitoring under these circumstances may be continuous or periodic, the latter having the advantage of consuming less power. Other aspects, features, and characteristics of the present invention are described in the detailed description that follows. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING The invention will be more fully understood with reference to the following detailed description in conjunction with the drawing, of which: Fig. la depicts a top view of a sunroof employing an object detection system in accordance with the present invention in which the sunroof is shown in an open position; Fig. lb is a side cross sectional view of the vehicular roof of Fig. la along section line BB and looking towards the front of the vehicle; Fig. Ic depicts a top view of a sunroof employing an object detection system in accordance with the present invention in which the sunroof is shown in a closed position; Fig. Id is a schematic diagram illustrating the theory of operation of an optical triangulation module as employed in the presently disclosed invention; Fig. le is a block diagram of the optical triangulation module as employed in the presently disclosed invention; Fig. 2a is a side view of a vehicle window illustrating the use of an optical triangulation module 'for detection of objects within a pinch zone along the upper region of the vehicle window opening; Fig. 2b is a side view of a vehicle window illustrating the use of an optical triangulation module for detection of objects within a pinch zone along the frontal region of the vehicle window opening; Fig. 2c is a side view of a vehicle window illustrating the use of multiple optical triangulation modules for detection of objects within pinch zones along the frontal and upper regions of the vehicle window opening; Fig. 2d is a side view of a vehicle window illustrating the use of an optical triangulation module for detection of objects along a diagonal extending from the lower front corner of the window opening to the upper rear corner of the window opening; Fig. 3a is a partial side view of a van illustrating the use of an optical triangulation module disposed on a "B" pillar for detection of objects within a pinch zone of a sliding door opening; Fig. 3b is a partial side view of a van illustrating the use of an optical triangulation module disposed on a leading edge of a sliding door for detection of objects within a pinch zone of a sliding door opening; Fig. 4a is a perspective view illustrating the use of an optical triangulation module for detection of objects within the pinch zone of a hinged door; Fig. 4b is a side view illustrating the use of an optical triangulation module for detection of objects within the pinch zone of a hatch; Fig. 4c is a top view illustrating the use of an optical triangulation module for detection of objects within the pinch zones of a revolving door; and Fig. 5 is a top view illustrating the use of an optical triangulation module in conjunction with an amplitude detection system for detection of objects' within the pinch zone of a vehicle sunroof. DETAILED DESCRIPTION OF THE INVENTION A method and apparatus for detecting the presence of an object within a pinch zone of an automated closure device such as a power sunroof, power window, or a powered door or hatch is disclosed. In each of the embodiments herein described, an optical ranging sensor is employed to provide an indication of the presence of an object within a pinch zone of the automated closure device. In response to the indication of the presence of an object within the pinch zone, the movement of the automated closure device may be halted or reversed to minimize the likelihood of personal injury or property damage that might result if the closure •device continued movement through the pinch zone. In another embodiment of the invention, a reflected IR amplitude detection system is employed in conjunction with the optical ranging sensor to improve the likelihood of the detection of an object within the pinch zone of the automated closure device . A powered sunroof is illustrated if Figs, la - lc in conjunction with an optical triangulation module. Referring to Fig. la, an automobile roof 10 has an opening 12 defined by a closure edge 14, first and second side edges 16 and 18, and a rear edge 20. A sunroof panel 22 is slidably movable within the roof 10 between an open position (see Fig. la) and a closed position (See Fig. lc) . In the open position, the sunroof 22 retracts into the roof 10 to allow fresh air and sunlight to enter the vehicle and in the closed position the sunroof 22 seals the opening in a conventional manner. A pinch zone for the illustrated closure device may be defined by the closure edge 14 of the opening 12, portions of the opening 12 sides 16 and 18 respectively, and a line AA located a predetermined distance rearward from the closure edge 14. This distance may be selected to allow an object 30 such as a human head to pass through the pinch zone between the closure edge and the line AA. It is desirable to detect the presence of objects within the pinch zone and halt closure of the sunroof 22 when objects are present within this zone to minimize the likelihood of personal injury or property damage should the heads or extremities of children or pets, or portions of objects, be extending through the sunroof 22 when the sunroof control mechanism is activated to close the sunroof 22. To detect the presence of an object 30 within the pinch zone, an optical triangulation module • 32 is mounted beneath the plane of slidable sunroof travel, as ■ depicted in Fig. lb. The optical triangulation module 32 includes an infra- red IR emitter 34 and a position sensitive detector 36 housed in a common package. The module 32 is selectively mounted adjacent one edge of the pinch zone and beneath the plane of sunroof 22 travel. The vehicle roof liner in this location is preferably adapted to receive the module 32 ' while minimizing abrupt projections. In an alternative embodiment, the emitter ' 34 and the detector 36 are disposed in discrete housings. In the absence of an object within the pinch zone, a beam 38a emitted by the emitter 34 traverses the pinch zone and impinges upon a reflector 40 conformably mounted below the plane of travel of the sunroof 22 on the opposite side of the pinch zone. The emitted beam 38a is reflected off of reflector 40 and impinges ' upon the position sensitive detector 36 at a first location. With reference to Fig. Id, the theory of operation of the optical triangulation module 34 is disclosed. An IR diode emits a modulated beam which is focused by optics such as a lens proximate the emitter. The beam hits an object and a portion of the light is reflected back through receiver optics to the PSD. In one embodiment, the PSD is realized as an array of photodiodes. Because object A is closer to the emitter, the light reflected from it enters the PSD lens at a greater angle than does light from distant object B. When light hits one of the photodiodes, current flows proportional to which photodiode is illuminated. The output current is compared to threshold levels, and a voltage proportional to the illuminated location on the photodiode array is generated. A predetermined correspondence between output voltage and object distance is referenced in order to resolve the distance to the reflecting object. However, in the present application, there is no need to resolve an absolute distance. Rather, the only determination to be made is whether the reflecting object is closer to the triangulation module than the unobstructed aperture environment, which may include the reflector disposed opposite the module. In a further embodiment, the test for an obstruction may be whether the reflected light energy is from an object at any distance greater or less than that of the unobstructed reflector. In the event an object 30 enters the pinch zone and obstructs the region just below the plane of sunroof 22 travel, the emitted beam 42a is reflected off the object 30 and the reflected beam 42b impinges on the surface of the position sensitive detector 36 at a location different from the first location. The position sensitive detector output signal is presented to comparison logic (discussed below in conjunction with a description of Fig. le) and the comparison logic generates a signal indicative of the presence of the object 30 within the pinch zone if the comparison logic input signal differs from the nominal PSD output signal by a predetermined value. More specifically, when the object 30 intrudes into the light beam path, the PSD within the optical triangulation module 32 will typically generate an output signal which may indicate a distance to the object less than the distance to the reflector 40. An obstacle which simply blocks the emitted beam 42a or which is so close to the module 32 that it is effectively out of the field of view of the detector 36 will result in an indication from the module 32 that no valid distance signal was received. This can be interpreted as being indicative of the presence of an obstacle. Upon the generation of an output signal from the comparison logic which indicates the presence of an object within the pinch zone, the actuator causing movement of the sunroof 22 is controlled to halt closure of the sunroof 22. Additionally, an alarm may be provided to alert the driver and passengers of the existence of the object 30 within the pinch zone. The sunroof motion may also be reversed in one embodiment. An illustrative block diagram of emitter drive logic and the comparison logic employed in the presently disclosed object detection system is depicted in Fig. le. Referring to Fig. le, a signal generator 50 generates the appropriate control signal for the triangulation module 55. This signal causes the LED drive 54, responsive to an internal control circuit 52, to illuminate the associated LED. Energy reflected from an object impinges upon a photodiode of the PSD 56, causing a characteristic output to be presented to the signal processing circuitry of the PSD 56. This output may be further processed by the internal control circuit 52 before passing to external comparison logic 51. Depending upon the device 55 used, the output may be a series of pulses explicitly characterizing the distance of the reflective object from the device 55, or may be a binary logic output indicative of whether the reflective object is beyond a certain distance from the device 55 or not. The external comparison logic 51, which may have a discrete memory (not shown) associated therewith, compares the received data from the device 55 and provides an output indicative of whether the reflected light energy is from an obstacle or from a reflector disposed on an opposite side of an aperture to be monitored. If a device 55 such as the Sharp GP2D05 is used, the internal signal processing circuit •56 may be programmed to provide a certain output if the reflective object is less than a certain distance from the device 55, thus potentially obviating the need for external comparison logic 51. The signal generator 50 and comparison logic 51 may be discrete circuits, or may be realized through the use of a programmable microprocessor and associated memory (not shown) . Figs. 2a - 2d illustrate alternative embodiments in which the automated closure device comprises an automotive power window and one or more optical triangulation modules are employed to detect the presence of an object within one or more respective pinch zones of the window. As depicted in Fig. 2a, a single optical triangulation module 100 is employed to detect the presence of an object within a pinch zone along the upper region of the window opening. The module 100 is mounted inside the vehicle and is selectively positioned such that an emitter 102 emits a beam which traverses the pinch zone. The emitted beam is reflected by a reflector 104 (also mounted within the vehicle) to the PSD 106 housed within the optical triangulation module 100. Operation of the system for detection of an object within the pinch zone along the upper region of the window opening is otherwise, as described above with respect to Figs, la - Id. The reflector 104 may be comprised of any material which results in the reflection of a substantial portion of the emitted IR beam to the PSD 106. It may be a discrete reflector element, may be an integral part of the vehicle interior trim, or may simply be the trim itself. These variants in the realization of the reflector apply to all of the embodiments disclosed herein. As depicted in Fig. 2b, an optical triangulation module • 110 and a reflector 112 may be mounted inside a vehicle to detect objects in a pinch zone along the frontal region of the window opening. Moreover, as depicted in Fig. 2c, multiple optical triangulation modules 120 and 122 may be employed in conjunction with respective reflectors 124 and 126 to provide a greater likelihood of detection of objects within both upper and frontal pinch zone regions of the window opening. It should be noted that the positions of the modules and reflectors may be reversed. Finally, as illustrated in Fig. 2d, an optical triangulation module 130 is mounted inside the vehicle adjacent the lower frontal portion of a window opening and a reflector 132 mounted inside the vehicle along the upper rearward region of the window opening so as to attempt to detect, with a single detection system, objects in the pinch zone along either the frontal region of the window opening or the upper region of the window opening. As illustrated in Fig. 3a, an optical triangulation module 140 may be mounted inside a vehicle along an upper edge of a sliding door 142 opening, proximate a vehicle λ B" pillar, such that an emitter within the module 140 emits an IR light beam that traverses a pinch zone along the frontal region of the door 142 opening. The emitted light beam impinges upon a reflector 144 mounted inside the vehicle on the opposite side of the door 142 opening such that the reflector 144 reflects the emitted light beam back to a position sensitive detector within the module 140 housing. Processing of the output signal from the position sensitive detector is performed as described above in conjunction with Figs, la-lc. Fig. 3b illustrates the placement of the optical triangulation module 140 on the leading edge of a sliding door 142. As the door processes, the emitted light beam impinges upon a reflector 144 mounted inside the vehicle on the lower edge of the door opening such that the reflector 144 reflects the emitted light beam back to a position ' sensitive detector within the module 140 housing. Processing of the output signal from the position sensitive detector is performed as described above in conjunction with Figs, la- lc. Other placements for the module 140 relative to the door opening are possible. For instance, one or more such optical triangulation modules 140 could be disposed on the "C" pillar for emitting light towards the Λ B" pillar and for receiving light reflected therefrom. If plural modules are used in this embodiment, a single processing element can be used to detect an obstacle, since knowledge of which module detected an obstacle is irrelevant. As illustrated in Figs. 4a-4c, an optical triangulation module 150 may be employed in conjunction with a reflector ■152 to detect the presence of an object within the pinch zone of a powered, hinged door 154, a powered hatch 156, or a powered revolving door 158. In contrast to the embodiments of Figs, la-lc, 2a-2d and 3a-3b, the closure in these situations swing out of the plane of the aperture. In the case of the powered hatch 156, the reflector (not visible) is disposed on the opposite side of the pinch zone from the optical triangulation module 150. Similarly, with respect to the top view of the revolving door 158, the reflector is disposed on the opposite side of the pinch zone from the optical triangulation module 150 and accordingly is not visible in the top view. It should be appreciated that in all of the embodiments, the position of the optical triangulation module and the reflector may be reversed, however greater signal to noise immunity may be achieved by positioning the optical triangulation modules at one particular side of the respective pinch zone. To increase the probability of detecting an object within a pinch zone of an automated closure device, including the devices described hereinabove, a reflected IR amplitude detector may be employed in combination with the optical triangulation module. More specifically and referring to Fig. 5, a signal generator (not shown) is employed to drive an IR emitter 160 at a designated frequency. The emitter 160 is selectively positioned such that a substantially planar light beam 162a emitted from the IR emitter 160 traverses at least a portion of the pinch zone and impinges upon the vehicle interior, potentially including the aperture trim, about the sunroof opening 12. A discrete reflector 164 may be provided to increase the power of the reflected signal in the absence of an obstacle. With no object in the light path, the aperture environment or alternatively the reflector 164 reflects at least a portion of the emitted light beam 162 (reflected portion not shown in Fig. 5 for simplicity sake) to an IR detector 166 located adjacent the emitter 160. The IR detector 166 generates an output signal indicative of the absence or presence of an object within the light path from the emitter 160 to the detector 166. For instance, the magnitude of the detector 166 output signal may vary with the received signal strength. Alternatively, the detector output signal may be provided as a series of pulses which vary in number, period or length as the received signal varies. In the event an object is present in the field of the emitted light beam 162, the amplitude of the signal reflected off the object is likely to vary based upon the size, orientation and reflectivity of the object. A 'variation in the output signal from the IR detector 166 observed in the absence of an object may be indicative of the presence of an object within the illuminated region of the aperture 12. Upon detection of such a variation in the output of the IR detector 166, a control signal is generated to halt the movement of the automated closure device. Movement of the closure member may be halted immediately upon detection of an object within the illuminated field or, alternatively, only when the leading edge of the closure member enters the pinch zone and an obstacle is detected. Additionally, movement of the moving member of an automated closure device may be halted upon detection of a signal, indicating the presence of an object within the pinch zone, .received from either the optical triangulation system or the IR amplitude detection system. The IR amplitude detector 166 of Fig. 5 comprises in general a photodiode and filter and processing circuitry including a memory. The photodiode is the element responsive to the reflected IR radiation, and typically generates an output proportional to the amplitude of the reflected radiation impinging thereon. The filter and processing circuitry applies filtering to the photodiode output signal to improve the signal to noise ratio. Additionally, the processing circuitry applies amplitude thresholding based upon a threshold or thresholds stored in •the associated memory. The thresholds so applied may be static, or may be dynamically adjusted in accordance with prior measurements of reflected energy in the absence of an obstacle. As previously noted, recognition of an obstacle may be the result of a decrease in reflected energy when the environment of the aperture is highly reflective or of a increase in reflected energy when the environment of the aperture is IR energy absorbing. The positioning of emitters and detectors for the presently described IR amplitude detection system may be generally as depicted for the optical triangulation detection system noting, however, that the detector in the IR amplitude detection system is measuring the amplitude of the received light beam rather than a location on the surface of a position sensitive detector. It should further be noted that upon detection of an object within the pinch zone of any of the above-described automated closure devices which have been activated to close, movement of the closure member may be halted immediately upon detection of the object within the pinch zone or, alternatively, only when the leading edge of the closure member enters the pinch zone. Furthermore, it should be noted that the combined optical triangulation detection system and IR amplitude detection systems illustrated in Fig. 5 may be employed in conjunction with any of the previously described automated closure devices. In addition to the use of the presently disclosed detector for preventing the capture of an object by a powered closure, it may also be used as part of an intrusion detection system. For instance, a vehicle having powered windows may be provided with an automatic venting system. Such a system automatically opens windows or a sunroof a predetermined amount to allow hot internal air to be vented outside the vehicle. Depending upon how far these closures are opened, an intruder may be able to insert a hand or ' other object inside the vehicle for the purpose of removing an article of value or unlocking a vehicle door to gain entry. The previously described system may be employed to continuously monitor the opening once automatic venting has been initiated. If an object is detected, an alarm may be sounded, or depending upon the embodiment, the powered closures may be commanded to close. The latter option must take into the consideration the potential for causing harm to either the intruder or intervening object. The response to such detection may also include disabling a vehicle ignition system or the automatic communication of an inaudible alarm signal to a remote receiver. The duty cycle for the detection system in this mode may be lower than that •in conjunction with obstacle detection for normal closure operation in order to conserve battery power. As an alternative to the use of an IR ranging system as described throughout the foregoing and as illustrated in Fig. Id, other technologies can be employed. For instance, it is possible to substitute the IR amplitude detection system with an ultrasonic system. A range detecting system based upon ultrasonic energy provides a distance measurement to an object in its beam path by measuring the short time intervals between transmitted and reflected bursts of ultrasonic sound. Depending upon the specific application, wide and narrow beam units can be employed, with detection •ranges being from approximately two inches to three feet . As with the IR ranging system, the absolute range to an object may not be necessary. Rather, the deviation of the reflecting surface from one distance to another distance can be employed as cause for recognizing the presence of an object. In a further embodiment, a thermal sensor can be employed in lieu of an IR system. Human body temperature corresponds to a peak blackbody emission of 10 microns. A suitable sensor for this wavelength is of the pyroelectric type, which are often found in automatic indoor or outdoor light switches. In most pyroelectric radiation detectors, the radiation is absorbed by a thin electrode whose thickness can be adjusted to make the absorption higher than 50% for the whole electromagnetic spectrum. The resulting change in temperature of the electrode in the presence of a radiating object yields a corresponding change in the output electric signal. The change in electric signal is compared by associated processing circuitry against a range of expected values to yield a determination of whether an object exists in the target field or not. In yet another embodiment, an RF ranging system is utilized. Such a system consists in its simplest form of a transmitter, an antenna, a receiver and a signal processor. The transmitter is responsible for providing the electromagnetic energy, while the antenna functions to concentrate the radiated energy into a shaped beam that points in the desired direction. A directional beam of RF energy is emitted across the region to be monitored, which in the present application is the pinch zone. Objects within the beam reflect a portion of the electromagnetic energy back to the system. The antenna collects the energy contained in the echo signal and delivers it to the receiver. This returned energy is amplified by the receiver and then analyzed by the radar processor. The radar processor analyzes the echo to establish if an object is present. Those of ordinary skill in the art should further appreciate that variations to and modification of the above- described methods and apparatus for providing object detection in an aperture in the path of a closure member may be made without departing from the inventive concepts disclosed herein. Accordingly, the invention should be viewed as limited solely by the scope and spirit of the appended claims.

Claims: CLAIMS 1. An obstruction detection circuit for an aperture, comprising: an emitter for emitting radiation proximate said aperture; a reflecting surface for reflecting at least a portion of said emitted radiation; and a receiver for receiving reflected radiation, said receiver providing an output signal dependent upon the position on said receiver said reflected radiation illuminates, if any. 2. The circuit of claim 1, wherein said reflected radiation comprises at least a portion of said emitted radiation as reflected from said reflecting surface. 3. The circuit of claim 1, wherein said reflected radiation comprises at least a portion of said emitted radiation as reflected from an object intermediate said emitter and said reflecting surface. 4. The circuit of claim 1, further comprising comparison logic, for receiving said receiver output signal and for comparing said output signal to a threshold value available to said comparison logic. 5. The circuit of claim 4, further comprising a memory unit in communication with said comparison logic for storing ' said threshold value. 6. The circuit of claim 1, further comprising comparison logic for receiving said receiver output signal and for comparing said output signal to a first set of acceptable values. 7. The circuit of claim 6, further comprising a memory unit in communication with said comparison logic for storing said first set of acceptable values. 8. The circuit of claim 1, wherein said receiver comprises a series of photodiodes, each having a characteristic output when illuminated by said reflected radiation. 9. The circuit of claim 1, further comprising a controller, responsive to said receiver output signal, for controlling a powered closure adapted for sealing said aperture. 10. The circuit of claim 9, wherein said controller is for controlling a powered closure adapted for sliding within said aperture. 11. The circuit of claim 9, wherein said controller is for controlling a powered closure adapted for hinged movement adjacent said aperture. 12. The circuit of claim 1, wherein said emitter comprises an infra-red wavelength emitter. 13. The circuit of claim 1, wherein said emitter is a light emitting diode. 14. The circuit of claim 1, wherein said receiver is a position sensitive detector. 15. The circuit of claim 1, further comprising: a second emitter for emitting a radiation plane proximate said aperture; and a second receiver for receiving reflected planar radiation, said second receiver providing an output signal dependent upon the amplitude, at said second receiver, of said reflected planar radiation. . 16. The circuit of claim 15, further comprising a controller, responsive to said receiver output signal and said second receiver output signal, for controlling a powered closure adapted for sealing said aperture. 17. The circuit of claim 16, wherein said controller is responsive to said second receiver output signal when said second receiver output signal is indicative of a variation in said second reflected radiation from an expected range of amplitude values . 18. The circuit of claim 16, wherein said controller is adapted for interrupting or inhibiting the closing of said powered closure in response to said receiver output signal and said second receiver output signal. 19. The circuit of claim 1, wherein said receiver output signal is one of two possible values. 20. The circuit of claim 19, wherein a first of said possible values is indicative of said reflected radiation illuminating a position within a first range of receiver positions, and a second of said possible values is indicative of said reflected radiation not illuminating a . position within said first range of receiver positions. 21. A method for detecting an obstacle proximate an .aperture having a powered closure operative therein, comprising: emitting, from an emitter, radiation proximate a portion of said aperture; receiving at least a portion of said emitted radiation, as reflected from at least one surface proximate said aperture, at a receiver; and generating a position signal, by said receiver, indicative of the position, on said receiver, said reflected, emitted radiation was received, if any. 22. The method of claim 21, wherein said step of generating further comprises generating said position signal indicative of a distance from said receiver to an object reflecting said reflected, emitted radiation. 23. The method of claim 21, wherein said step of generating further comprises generating said position signal indicative of whether said reflected, emitted radiation was received on a first portion of said receiver. 24. The method of claim 21, wherein said step of generating further comprises generating a position signal indicative of the failure of said receiver to receive at least a portion of said emitted radiation. 25. The method of claim 21, further comprising the step of determining if said position signal is indicative of receipt of any of said reflected, emitted radiation at said receiver. 26. The method of claim 21, further comprising the step of comparing said position signal to a threshold value. 27. The method of claim 26, wherein said step of comparing comprises comparing said position signal to a threshold value reflective of an acceptable distance from said receiver to an object reflecting said reflected, emitted radiation. 28. The method of claim 26, further comprising the step of controlling a power actuated closure for said aperture in response to said step of comparing. 29. The method of claim 21, further comprising: emitting, from a second emitter, a radiation plane adjacent said aperture; receiving at least a portion of said emitted radiation plane, as reflected from the environment of said aperture, at a second receiver; and generating an amplitude signal, by said second receiver, indicative of the amplitude of said reflected, emitted radiation plane as received at said second receiver. 30. The method of claim 29, further comprising the step of controlling a power actuated closure for said aperture based upon said position signal and said amplitude signal. 31. A system for detecting an obstacle proximate and aperture sealable by a powered closure, comprising: a first emitter for selectively emitting a focused beam of light energy proximate said aperture; a first receiver for receiving at least a portion of said emitted focused beam as reflected from one or more reflecting surfaces proximate said aperture and for generating a first output signal indicative of a location on said first receiver at which said reflected, focused beam is received; and a controller for controlling said powered closure in response to said first output. 32. The system of claim 31, wherein said first receiver is further for failing to receive at least a portion of said emitted focused beam as reflected from any reflecting surfaces proximate said aperture and for generating a first output signal indicative of said failure to receive. 33. The system of claim 31, further comprising: a second emitter for selectively emitting a planar beam of light energy proximate said aperture; and a second receiver for receiving at least a portion of said emitted planar beam as reflected from one or more reflecting surfaces proximate said aperture and for generating a second output signal indicative of the relative strength of said reflected, planar beam as received by said second receiver, . wherein said controller is further for controlling said powered closure in response to said second output. 34. The system of claim 33, further comprising a memory in association with said controller for storing one or more threshold values for comparison by said controller against said first and second outputs. 35. The system of claim 33, wherein said first output is indicative of a relative distance between an object reflecting at least a portion of said emitted focused beam and said first receiver. 36. The system of claim 35, wherein said controller is operative to stop, reverse or inhibit the motion of said powered closure if said relative distance is below a threshold value. 37. The system of claim 36, wherein said controller is operative to stop, reverse or inhibit the motion of said powered closure if said relative distance is below a threshold value and if said relative strength of said reflected, planar beam is beyond a prescribed threshold value. 38. A method of detecting an obstacle proximate an aperture sealable by a powered closure, comprising: emitting a focused beam of light energy proximate said aperture; attempting to receive a reflected portion of said focused beam at a location on a position sensitive detector; generating a first output signal indicative of said location on said position sensitive detector if said reflected portion of said focused beam is received; and comparing said first output signal to a threshold value to infer whether said reflected portion of said focused beam is reflected off an obstacle proximate said aperture. 39. The method of claim 38, further comprising the step of generating said first output signal indicative of the failure to receive said reflected portion of said focused beam on said position sensitive detector. 40. The method of claim 38, further comprising the step of selectively stopping, reversing or inhibiting the motion of said powered closure in response to said step of comparing. 41. The method of claim 38, further comprising the steps of: emitting a planar beam of light energy proximate said aperture; receiving a reflected portion of said planar beam at an amplitude sensitive detector; generating a second output signal indicative of the amplitude of said reflected portion as detected by said amplitude sensitive detector; and comparing said second output signal to a threshold value to infer whether said reflected portion of said planar beam is reflected off an obstacle proximate said aperture. 42. The method of claim 41, further comprising the step of selectively stopping, reversing or inhibiting the motion of said powered closure in response to said steps of comparing ' said first and second output signals to the respective threshold value.

Inventors: HAWLEY STEPHEN A, O'CONNOR CHRISTOPHER J, HAWLEY, STEPHEN, A., O'CONNOR, CHRISTOPHER, J.
Applicants: PROSPECTS CORP, PROSPECTS, CORP.
Application year: 2000
Main classification: H02P1
IPC codes: B60J7, E05F15, G01B11, G01V8