Abstract:
A system for monitoring a load for displacement on a vehicle, comprising a support structure adapted to be fixed to the vehicle. A sensor is supported by the support structure. The sensor is positioned with respect to the load so as to detect a displacement of the load with respect to the vehicle. An interface receives and processes signals from the sensor and to a user of the vehicle.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This patent application claims priority on U.S. Provisional Patent Application No. 60/491,967, filed on Aug. 4, 2003, by the present Applicants. 
     
    
     TECHNICAL FIELD  
       [0002]     The present invention generally relates to the freight industry and, more particularly, to a sensor system for monitoring load displacements in freight vehicles.  
       BACKGROUND ART  
       [0003]     In the freight industry, loads are transported using various types of vehicles: trucks, trains, boats and planes. Loads carried by such vehicles are subjected to displacement forces to a varying extent as a function of these vehicles. Factors such as the nature of the transportation (airborne, on rails, on a road, on water), the velocity of the vehicles, braking and accelerating forces, gravity, each have an effect on the displacement forces on the loads within the vehicles. As an example, the road transport vehicles represent the most versatile solution amongst these vehicles for terrestrial transportation. These vehicles may have a load carrying surface or container as an integral part thereof, or as a detachable part, such as a trailer. The trailer may take the form of a container (e.g., van) or of an exposed surface (e.g., flat bed).  
         [0004]     A disadvantage of the road transport vehicle over the other types of vehicles is related to the versatility of the road vehicle. As it travels on the roads, the road vehicle performs sharp movements when compared to the other freight vehicles. For instance, the road vehicle must perform sharper turns and more abrupt stops than the other freight vehicles. Moreover, the road vehicle is subjected to the road conditions, including defects in the surfacing of the road, type of pavement (e.g., gravel or dirt road), weather conditions (e.g., presence of ice on the road), and slopes.  
         [0005]     Accordingly, loads carried by freight trucks are subjected to displacements because of the road conditions and/or sharp movements of the vehicles. Also, the nature of the load may cause some inconvenience with regards to its transportation. For example, pipes are strapped onto a flat bed, piled up on one another. Such loads frequently move during transportation as a result from the shocks sustained.  
         [0006]     A load displacement results in a change in the weight distribution of the freight vehicle. This change in weight distribution has an effect on the maneuverability of the vehicle, and this may ultimately result in severe consequences. Freight trucks with an uneven weight distribution represent a road hazard. The unequal weight distribution caused by movement of the load may result in truck roll-over, or in the loads falling off the truck in open-air transport. In the latter case, the fallen loads represent a danger for the surrounding vehicles.  
       SUMMARY OF INVENTION  
       [0007]     Therefore, it is a feature of the present invention to provide a sensor system for monitoring load displacement of freight vehicles.  
         [0008]     It is a further feature of the present invention that the load monitoring sensor system provide displacement orientation and magnitude.  
         [0009]     Therefore, in accordance with the present invention, there is provided a sensor for detecting displacement of a load in a freight vehicle, comprising a fixed portion adapted to be secured to the freight vehicle in a given position, with respect to the load, a movable portion adapted to be releasably connected to the load so as to be displaced by displacements of the load, a joint interconnecting the fixed portion to the movable portion so as to allow relative motion between the fixed portion and the movable portion, and a signal generator connected to any of the fixed portion, the movable portion and the joint so as to detect relative motion between the fixed portion and the movable portion so as to signal a displacement of the load.  
         [0010]     Further in accordance with the present invention, there is provided a method for signaling a displacement of a load in a freight vehicle, comprising the steps of providing a sensor positioned with respect to the load such that the sensor is triggered by a displacement of the load with respect to the freight vehicle, obtaining a signal from the sensor for the displacement, and sending the signal to a driver of the freight vehicle to indicate that the load has been subjected to a displacement. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0011]     A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which:  
         [0012]      FIG. 1  is a schematic view, partly sectioned, of a sensor for monitoring load displacements, constructed in accordance with a preferred embodiment of the present invention; and  
         [0013]      FIG. 2  is a block diagram of a sensor system for monitoring load displacements, constructed in accordance with a preferred embodiment of the present invention. 
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0014]     Referring to the drawings and, more particularly, to  FIG. 1 , a sensor for monitoring load displacements is generally shown at  10 . The sensor  10  is supported in a desired position by a support structure  11 . The support structure  11  is preferably positioned in the load carrying portion of the vehicle, adjacent to a load  12 . For instance, the support structure  11  is fixed to a support surface  13  of the vehicle, and is thus the fixed portion of the sensor  10 .  
         [0015]     The support structure  11  may be provided with various configurations to enable the position and orientation adjustment of the sensor  10  with respect to the load  12 . For example, the support structure  11  has a telescopic mechanism for the adjustment of the vertical position of the sensor  10 , and to be pivotable about a longitudinal axis of the telescopic mechanism. The sensor  10  has a sensor arm  20 , a receptacle  30  secured to the support structure  11  to form the fixed portion, and a joint member  40  operatively connecting the sensor arm  20  to the receptacle  30 .  
         [0016]     The sensor arm  20  is the movable portion of the sensor  10 . The sensor arm  20  contacts the load  12 , so as to be subjected to the displacements of the load  12 . More specifically, the sensor arm  20  has an elongated stem portion  21  (i.e., rod) with an elbow portion  22  at an end thereof. The elbow portion  22  has a free connection end  23  thereof received in a bracket  24  of the sensor arm  20  that is secured to the load  12 .  
         [0017]     Preferably, the free end  23  of the elbow  22  has a ball. Accordingly, the ball forms a ball joint with a receptacle portion of the bracket  24 , having a spherical shape. Resilient members are preferably provided such that the ball of the free end  23  is releasably retained within the bracket  24 .  
         [0018]     The bracket  24  has suitable fasteners so as to be anchored to the load  12 . The suitable fasteners depend on the type of load being carried. For instance, adhesives can be used if the load  12  is cardboard boxes. Alternatively, the bracket  24  may be provided with a clamp, tie wrap or similar devices, to be fixed to other shapes, such as a pipe.  
         [0019]     According to a preferred embodiment of the present invention, the sensor arm  20  supports a signal generator consisting of four triggers  25  (three of which are visible in  FIG. 1 ), namely an upwardly oriented trigger, a downwardly oriented trigger, and right and left oriented triggers. The triggers  25  are pivotable toward the elongated stem portion  21 , but are biased to return to the idle positions illustrated in  FIG. 1 . The signal generator also has a pair of triggers  26  on the front and back of the sensor arm  20 , the triggers  26  being generally radially positioned with respect to the elongated stem portion  21 .  
         [0020]     The receptacle  30  has a cylindrical hollow receptacle body  31 . The cylindrical hollow body  31  has a cylindrical inner surface  32 . Opposed ends  33  and  34  of the cylindrical hollow body  31  each have a concentric opening,  35  and  36 , respectively.  
         [0021]     The sensor arm  20  is held by the joint member  40 , so as to have the stem portion  21  superposed with a central axis X of the cylindrical hollow body  31 . According to a preferred embodiment of the present invention, the joint member  40  is a conical spring  41 . The conical spring  41  is concentrically positioned with respect to the cylindrical hollow body  31 . The conical spring  41  has a larger end  42  thereof connected to the end  33 , and is positioned about the opening  35  in the cylindrical hollow body  31 . The smaller end  43  of the conical spring holds the stem portion  21  of the sensor arm  20 , such that stem portion  21  is superposed on the axis X of the cylindrical hollow body  31 .  
         [0022]     The joint member  40  must allow the pivoting motion of the sensor arm  20  with respect to the receptacle  30 . Moreover, the joint member  40  must also allow back and forth movement of the sensor arm  20  along the central axis X of the cylindrical body  31 . Various types of joint members may be used for this purpose, but a spring represents a simple and cost effective solution. Moreover, a spring, such as the conical spring  41 , biases the sensor arm  20  back to its initial position of  FIG. 1 , if the free end  23  is separated from the load. Finally, it is preferred to use a conical spring, such as the conical spring  41 , as its larger end will allow the sensor arm  20  to move within the receptacle  30 .  
         [0023]     The cylindrical inner surface  32  defines an abutment surface for the triggers  25 . If the sensor arm  20  is displaced beyond a certain value away from the central axis X of the cylindrical body  31 , at least one of the triggers  25  will come into contact with the inner surface  32 , and will thus generates a signal. Therefore, if the load  12  moves up or down, or left or right, the triggers  25  will signal this movement by coming into contact with the inner surface  32 .  
         [0024]     The triggers  26  are provided to signal the movement of the sensor arm  20  along the axis X. One of the triggers  26  is provided on a first side of the end  34  of the cylindrical body  31 , whereas the other trigger  26  is provided on the second side of the end  34 , within the cylindrical body  31 . Accordingly, a movement of the sensor arm  20  along the axis X will cause either one of the triggers  26  to be actuated. Therefore, forward and rearward movements of the load  12  are detected.  
         [0025]     It is pointed out that other possible configurations for signal generator are contemplated. For instance, the sensor arm  20  may be charged, with contact between the sensor arm  20  and the inner surface  32  closing circuitry to send a signal to the driver. In such a configuration, the inner surface  32  of the receptacle  30  could be provided with segments each representing a direction of displacement of the load, as an alternative to the plurality of triggers  25  and  26 .  
         [0026]     Referring to  FIG. 2 , the sensor  10  is shown connected to an interface apparatus  50 . Although not illustrated in  FIG. 1 , wires are provided for every trigger  25  and  26 . Preferably, wires pass through a free end of the sensor arm  20  to be connected to the interface apparatus  50 . The wires must not interfere with the movement of the sensor arm  20  within the receptacle  30 .  
         [0027]     Referring to  FIG. 2 , the interface apparatus  50  is preferably received in the driver/pilot cabin so as to be in the visual or auditive range of the driver/pilot. The interface apparatus  50  must indicate a load displacement to the driver/pilot. In a preferred embodiment of the present invention, the interface apparatus  50  has a microprocessor so as to receive and interpret the signals from the triggers  25  and  26 , and convert these signals to an indication of load displacement to the driver/pilot.  
         [0028]     According to a preferred embodiment of the present invention, the sensor  10  indicates an orientation and a magnitude of the load displacement. More specifically, each of the triggers  25  and  26  are related to a displacement of the load  12  in a specific direction (i.e., up/down, left/right, and forward/rearward, or combinations of at most three of these directions). Also, the triggers  25  and  26  may provide a magnitude of the load displacement. For instance, a displacement of one of the triggers  25  and  26  from an initial position is quantified in magnitude.  
         [0029]     Accordingly, the load displacement may be associated with a value, or with a worded level (e.g., small displacement, large displacement), to provide an idea to the driver/pilot of the importance of the load displacement. For instance, a “small” load displacement may warn the driver/pilot to slow down, and the orientation may add that the slowing down is required in curves. On the other hand, a “large” load displacement may indicate to the driver/pilot that the load should be attended to in view of possible hazards due to the large load displacement.  
         [0030]     Returning to  FIG. 1 , it is seen that the end  34  has a concave shape with respect to an inner cavity of the receptacle  30 . According to a preferred embodiment of the present invention, a radius of curvature of the end  34  coincides with a pivot point between the sensor arm  20  and the receptacle  30  (i.e., at the connection between the sensor arm  20  and the joint member  40 ). This concavity in the end  34  will ensure that any pivoting motion of the sensor arm  20  away from the axis X will not have an effect on the magnitude indicated by the triggers  26 .  
         [0031]     The free end  23 /bracket  24  combination of the sensor arm  20  must be provided with a disconnection indicator. For instance, the outer surface of the free end  23  may be provided with switches that are actuated when the free end  23  is not in an appropriate position within the bracket  24 . Advantageously, if the free end  23  inadvertently exits the bracket  24 , an indication that the sensor  10  is non-functional can be displayed to the driver/pilot.  
         [0032]     Other possible configurations are possible to detect the load movement. For instance, visual detectors may suitably be used to monitor load displacements. However, by connecting the sensor  10  to the load  12 , a single sensor is required to monitor load displacements in orientation and magnitude. It is also conceivable that the signals from the sensor  10  be recorded for further use. Alternatively, the interface apparatus  50  could be accessed remotely by wireless equipment.  
         [0033]     It is within the ambit of the present invention to cover any obvious modifications of the embodiments described herein, provided such modifications fall within the scope of the appended claims.