Abstract: Evaluating the operating safety of a complex software and or hardware system such as a system for displaying flight information on an instrument panel of an aircraft. The evaluation method includes construction of a first architecture of the system, divided into several blocks each comprising data inputs/outputs, the inputs of a block being connected to the outputs of other blocks in the first architecture; identification of failures of the outputs of the blocks of the architecture; construction of first boolean expressions expressing the states of the outputs of the blocks of the first architecture as a function of the states of the identified failures, of the states of the inputs of the blocks; definition of a first feared event to be examined by a second boolean expression constructed based on the first boolean expressions; and reduction of the second boolean expression in a sum of monomials.

Abstract: Evaluating the operating safety of a complex software and or hardware system such as a system for displaying flight information on an instrument panel of an aircraft. The evaluation method includes construction of a first architecture of the system, divided into several blocks each comprising data inputs/outputs, the inputs of a block being connected to the outputs of other blocks in the first architecture; identification of failures of the outputs of the blocks of the architecture; construction of first boolean expressions expressing the states of the outputs of the blocks of the first architecture as a function of the states of the identified failures, of the states of the inputs of the blocks; definition of a first feared event to be examined by a second boolean expression constructed based on the first boolean expressions; and reduction of the second boolean expression in a sum of monomials.

Abstract: A snowplow and mount assembly comprising a mount frame adapted to be secured to a vehicle, and a snowplow frame. One of the mount frame and the snowplow frame has first and second arms and the other of the mount frame and snowplow frame has first and second receivers, the first and second receivers receiving the first and second arms, respectively. Respective ones of first and second latch pins removably secure the first and second arms in the first and second receivers. A latch lever is operably associated with the first and second latch pins and simultaneously actuates the latch pins to latched and unlatched positions. The snowplow frame includes a jack stand movable to and between an extended ground contacting and snowplow frame supporting position and a retracted ground noncontacting and snowplow frame nonsupporting position.

Abstract: A snowplow assembly comprises a lift frame and A-frame operably pivotally connected together and an actuator operably connected between the lift frame and A-frame for effecting relative pivotal movement between the lift frame and A-frame. A plow blade includes a blade frame. The blade frame includes a tube of circular cross section which is operably pivotally connected to the A-frame. The tube is pivotally received by a quadrant, which is operably connected to the A-frame. A resilient element is operable between the blade frame and A-frame normally biasing a lower edge of the plow blade forwardly. The resilient element is an elastomeric loop. The pivotal connection of the plow blade to the A-frame in combination with the resilient element provides a trip function of the plow blade. The plow blade is a composite. The circular tube of the blade frame provides torsional stiffness to the composite blade.

Abstract: A snowplow assembly comprises a lift frame and A-frame operably pivotally connected together and an actuator operably connected between the lift frame and A-frame for effecting relative pivotal movement between the lift frame and A-frame. A plow blade includes a blade frame. The blade frame includes a tube of circular cross section which is operably pivotally connected to the A-frame. The tube is pivotally received by a quadrant, which is operably connected to the A-frame. A resilient element is operable between the blade frame and A-frame normally biasing a lower edge of the plow blade forwardly. The resilient element is an elastomeric loop. The pivotal connection of the plow blade to the A-frame in combination with the resilient element provides a trip function of the plow blade. The plow blade is a composite. The circular tube of the blade frame provides torsional stiffness to the composite blade.

Abstract: A snowplow assembly comprises a lift frame and A-frame operably pivotally connected together and an actuator operably connected between the lift frame and A-frame for effecting relative pivotal movement between the lift frame and A-frame. A plow blade includes a blade frame. The blade frame includes a tube of circular cross section which is operably pivotally connected to the A-frame. The tube is pivotally received by a quadrant, which is operably connected to the A-frame. A resilient element is operable between the blade frame and A-frame normally biasing a lower edge of the plow blade forwardly. The resilient element is an elastomeric loop. The pivotal connection of the plow blade to the A-frame in combination with the resilient element provides a trip function of the plow blade. The plow blade is a composite. The circular tube of the blade frame provides torsional stiffness to the composite blade.

Abstract: Method for longitudinal cutting of a wall of a fibrous tubular product in a step shaped profile. The apparatus comprises two parallel main blades which form radial cuts into the wall, slightly displaced from each other. One cut is made radially inward from the outer surface; and the other cut is made radially outward from the inner surface. Each cut extends toward the center of the shell wall to a depth approximately one half the thickness of the shell wall. A third cut is made within the shell wall perpendicular to and joining the other two cuts. These three cuts form a smooth step shaped cut through the wall and facilitate installation of the shell around conduit while minimizing heat loss and mechanical stresses within the wall.