Patent Application
20070212184
This invention relates to vehicle load floors having selectively variable friction characteristics.
Vehicles often include a load floor configured to support cargo in a cargo area. For example, minivans and sport-utility vehicles typically include a cargo area in the rear of the vehicle. Access to the cargo area is provided by a rear body opening that is selectively closed by a rear closure panel, such as a tailgate or a liftgate. Similarly, pickup trucks include a cargo area, i.e., a cargo box, with access to the cargo box being provided by an opening at the rear of the truck and that is selectively closed by a tailgate. The load floor forms the lower surface of the cargo area or cargo box.
Loading cargo into the cargo area may include sliding the cargo on the load floor to push the cargo into a desired position for transport. Some prior art vehicles include movable load floors that are movable rearward outside the body opening for loading cargo, and that are then movable inside the cargo area with the cargo placed thereon.
A vehicle is provided that includes a body at least partially defining a cargo area. The vehicle also includes a load floor having a surface that further defines the cargo area. The load floor is characterized by selectively variable friction characteristics. Thus, the load floor may alternately provide a relatively small amount of friction to provide a relatively small amount of resistance to the movement of cargo across the surface, thereby facilitating loading and unloading of the cargo, and a relatively high amount of friction to provide a relatively high amount of resistance to the movement of cargo across the surface, thereby preventing movement of the cargo during vehicle movement.
In an exemplary embodiment, the load floor is configured such that the friction characteristics change as a result of the presence of at least one predetermined condition. For example, if the engine is running, the vehicle is moving, or the ignition switch is in the “on” position, then the load floor increases friction to minimize or prevent movement of cargo during transport. If the engine is not running, the vehicle is at rest, or the ignition switch is in the “off” position, then the load floor decreases friction to allow cargo to more easily slide during loading or unloading.
The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.
Referring to
The vehicle body 14 is for a sport-utility style vehicle in the embodiment depicted. However, other body styles defining a cargo area may be employed within the scope of the claimed invention. For example, the vehicle body may be for a minivan, pickup truck, etc. within the scope of the claimed invention.
The load floor 26 includes an upper load floor member 42 that has a surface 46 that forms a first portion of a load floor surface 48 that is exposed to, and defines the lower extent of, the cargo area 30. Within the scope of the claimed invention, an “upper load floor member” may comprise multiple pieces. For example, an upper load floor may include a structural portion formed from stamped metal, and an aesthetic covering, such as carpeting or padding, that defines the surface 46. The member 42 defines a plurality of elongated apertures, namely slots 50 that are longitudinally oriented with respect to the vehicle 10.
The movable member 60 is shown in a first position in which the strips 66 are located below the upper surface 66 of the upper load floor member 42, and do not project through slots 50. Thus, when the movable member is in the first position, the strips 66, and therefore the second portion 70 of the load floor surface 48, do not protrude from the surface 46 of the upper load floor member into the cargo area 30. Cargo 71 therefore rests on surface 46 of the upper load floor member 46 and not on the strips 66 or the second portion 70 of the load floor surface 48.
The vehicle 10 includes two actuators 72 that are operatively connected to the movable member 60, and that are configured to selectively move the movable member 60, and correspondingly the support plate 62 and the elastomeric strips 66, up and down. Those skilled in the art will recognize a variety of actuators that may be employed within the scope of the claimed invention, such as servomotors, solenoids, shape memory materials, etc. As understood by those skilled in the art, a shape memory material assumes a predetermined shape when exposed to a stimulus such as heat. The heat may be supplied, for example, by electrical resistance heating of the shape memory material.
More particularly, the actuators 72 are configured to move the movable member 60 from the first position shown in
Accordingly, cargo 71 rests on the strips 66 of elastomeric material and on the second portion 70 of the load floor surface 48, and not on the surface 46 of the upper load floor member 42. The surface 46 of the upper load floor member 42, i.e., the first portion of load floor surface 48, is characterized by a first coefficient of friction with the cargo 71. The elastomeric strips 66, and correspondingly the second portion 70 of the load floor surface 48, have a second coefficient of friction with the cargo 71 different from the coefficient of friction of surface 46, i.e., the first coefficient of friction. Accordingly, the friction characteristics of the load floor 26 are selectively variable by moving the movable member 60 between the first and second positions.
In the embodiment depicted, the second coefficient of friction is higher than the first coefficient of friction, and therefore the strips 66 provide greater resistance to the movement of cargo 71 thereacross than the surface 46. However, and within the scope of the claimed invention, the portion of the load floor surface defined by the movable member 60 may have a lower coefficient of friction than surface 46. Such a configuration would be desirable if a shape memory material is used as an actuator because energy would be required to maintain the support plate and strips in the second position.
More specifically, if a shape memory material is used as an actuator, the predetermined shape that the material assumes when subjected to the stimulus would likely be such that the shape memory material forces the movable member 60 to the second position. Once the stimulus is removed, the movable member 60 would return to the first position. It is expected that the high friction setting of the load floor would be used more frequently than the low friction setting. Accordingly, to minimize the amount of energy that must be expended to maintain the shape memory material in the predetermined shape, the low friction setting should occur with the movable member in the second position.
Further, and within the scope of the claimed invention, the movable member 60 may have mechanisms, such as rollers, that replace strips 66 to provide less resistance to the movement of cargo than the surface 46 of the upper load floor member. In an exemplary embodiment, rollers or bearings would define the second portion of the load floor surface, and be attached to the plate 62 to protrude through the apertures 50 when the movable member 60 is in the second position. Referring to
Referring again to
More specifically, the load floor 26 includes a controller 76 that is operatively connected to the actuators 72 to selectively cause the actuators 72 to move the movable member 60 between the first and second positions. Sensors 80 are configured to monitor various vehicle components and transmit signals 84 indicative of the status of the components to the controller 76. Exemplary components monitored by the sensors 80 include the vehicle's engine 88, the vehicle's ignition switch 92, and the vehicle's wheels 96. The sensors 80 may also monitor the inclination of the vehicle to determine whether the vehicle is on a hill.
The controller 76 receives signals 84 and determines whether or not a predetermined condition exists, such as the engine 88 running, the ignition switch 92 being in the “on” position, or the wheels 96 rotating. If the controller 76 determines that the predetermined condition exists, then it causes the movable member 60 to move to the second position, as shown in
Thus, if the controller determines that a predetermined condition indicative of vehicle movement exists, such as the engine running, the ignition switch being in the “on” position, or the wheels rotating, or that the vehicle is on an inclined surface, the load floor surface 48 provides a higher level of friction with respect to the cargo 71 to resist movment of the cargo across the load floor surface 48. Otherwise, the load floor surface provides a lower level of friction with respect to the cargo to facilitate movement of the cargo across the load floor surface 48 for loading and unloading. Alternatively, the higher level of friction may be a default condition unless a predetermined condition exists that indicates that cargo is to be loaded or unloaded, such as when the liftgate (shown at 38 in
Although the load floor depicted is automated, a load floor may be manually operated within the scope of the claimed invention. For example, a switch (not shown) may be operable by a vehicle user to cause the actuators 72 to move the platform between the first and second positions, and thereby cause the friction characteristics of the load floor surface 48 to vary. Similarly, and within the scope of the claimed invention, actuators 72 may be replaced by a manually-operated mechanism, such as a hand crank, a four-bar linkage, etc.
When the movable member 60 is in the second position as shown in
Referring to
Referring to
While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.
