Vehicle mounted snowplow impact monitoring system and method

#Typical snowplow systems designed to be mounted on smaller vehicles, such as pickup trucks or sport utility vehicles, operate by providing a plow blade pivotally mounted on a support arm which, in turn, is pivotally mounted to the vehicle frame. A first mechanism is used to raise or lower the plow by causing the support arm to pivot around an axis proximate the vehicle. This first mechanism is usually a hydraulic piston assembly or, in simpler cases, an electric winch. While plowing, the plow is in a lowered position and can pivot around a horizontal axis defined by a hinge which connects the plow to the distal end of the support arm. A spring or similar biasing mechanism extends from an attachment point on the support arm to another attachment point on the top of the plow. The spring controls the rotation of the plow around its axis of rotation by biasing the lower, leading edge of the plow in a forward direction. In the event that the plow contacts a relatively immovable object, the plow is allowed to rotate around its hinge such that the leading edge rotates rearwardly, thereby stretching the spring. Once the object has passed under the leading edge, the spring pulls the top edge of the plow back, thereby rotating the leading edge forward to its normal operating position. This damping feature protects the vehicle frame from encountering excessive forces during a plowing operation.

#Rudimentary systems rely on the weight and shape of the plow to provide the downward force necessary to keep the plow close to the ground during operation. More advanced systems have additional measures for providing downward force. Such force is desirable when using a plow to scrape hard-packed snow and ice from a road's surface. Providing such a downward force must be done in a controlled manner to prevent injury to the plow and vehicle. Existing systems utilize hydraulic pressure sensors in order to maintain a predetermined downward pressure on the blade of the plow. Unfortunately, there are many problems pertaining to the complexity of these systems.

#Existing hydraulic systems must be installed on the carrier vehicle at the factory while the vehicle is being assembled. Their complexity and structural requirements preclude them from being added to existing vehicles as an after-market retrofit. Therefore, a decision must be made at the time the sport utility vehicle or pickup truck is being purchased as to whether it will ever be used as a snowplow.

#FIG. 1 is a schematic drawing of an embodiment of a snow plow system of the present invention;

#FIG. 2 is a schematic drawing of an alternative embodiment of a snow plow system of the present invention;

#FIG. 3 is a schematic drawing of another alternative embodiment of a snow plow system of the present invention;

#Referring to FIG. 1, there is shown a snow plow system 100 which is attachable to an existing light truck such as a pickup truck or sport utility vehicle. Snow plow system 100 generally comprises a mounting bracket 180, mountable to a vehicle frame 160. The vehicle frame 160 is attached to an axle 210, preferably through a suspension mechanism such as a vehicle spring 200. The snow plow system 100 includes a support arm 110 which is attached to plow blade 120 at its forward end. Preferably, the plow blade 120 is pivotally attached to support arm 110 and can pivot forwardly and rearwardly around a horizontal axis. A spring (not shown) may be provided to pull the top portion of the plow blade 120 rearward toward support arm 110, thereby biasing the bottom edge of plow blade 120 forward.

#Support arm 110 is pivotally attached at its rearward end to the mounting bracket 180, such that support arm 110 may be raised and lowered around a horizontal axis by positioner 130. Positioner 130 is attached at one end to vehicle frame 160 and at the other end to support arm 110. In the preferred embodiment, to effect the raising and lowering of support arm 110, positioner 130 includes at least one hydraulic cylinder 132. The hydraulic cylinder 132 houses a piston that may slide within the cylinder 132 and is connected to a push rod 134 which makes up the end of the cylinder 132 attached to support arm 110. An oil distribution box (not shown) houses valves used to port hydraulic oil to and from either side of the piston, thereby causing the piston to slide back and forth within the cylinder 132, raising and lowering support arm 110. Pressurized hydraulic fluid is supplied by a hydraulic oil pump (not shown).

#The snow plow system 100 measures the impact mounting bracket 180 has on vehicle frame 160 during operation and particularly whether the impact increases above or drops below a predetermined set load. This measurement is taken using sensor 140 that is attached to vehicle frame 160. When the snow plow system 100 is operating, the sensor 140 measures fluctuations in the load felt by vehicle frame 160 by detecting variations in the distance between the vehicle frame 160 and a reference point. The reference point is a point fixed relative to at least one of the wheels such as bracket 220 attached to vehicle axle 210, shown in FIG. 1, or the ground 240, shown in FIG. 2. Sensor 140 interprets these fluctuations as indicative of the impact felt by vehicle frame 160 from the mounting bracket 180 and sends corresponding data, mechanical or electrical, to control system 150. The control system 150 uses the data to determine whether the load has changed from the predetermined set load, and what reaction is appropriate, as described below.