Obstacle detection system

A self guided material handling vehicle having a frame upper end portion and a vehicle operating system having an onboard computer, comprising:

• a laser scanning device having an elevationally oriented axis of rotation and being mounted on the frame upper end portion and connected to said onboard computer, said laser scanning device being adapted to deliver a laser signal in directions transversely about said elevationally oriented axis of rotation, to receive a reflection of the laser signal, and to deliver a position control signal in response to receiving the reflected laser signal;
• a supporting assembly connected to the frame upper end portion and extending upwardly from the frame upper end portion at a location adjacent the laser scanning device;
• means for delivering a light signal in a direction along an elevationally oriented axis, said delivering means being connected to said frame upper end portion;
• a guide frame connected to the supporting assembly and defining a plane passing through the light signal axis at a preselected location above said laser scanning device;
• a reflecting member supported on said guide frame and movable in directions along said plane;
• means for receiving a reflection of said light signal and delivering a condition signal in response to receiving said reflected light signal, said receiving means being connected to said frame upper end portion and said computer and being adapted to deliver said condition control signal to said computer;
• means for connecting the reflecting member to the supporting assembly and maintaining said reflecting member for movement substantially along the plane defined by the guide frame between a first position, at which said reflecting member intersects said delivering means light signal elevationally oriented axis and reflects said light signal toward said receiving means, and a second position, spaced from said first position, at which said reflecting means is free from intersecting the light signal elevationally oriented axis of the delivering means and is free from reflecting a sufficient amount of said light signal toward said receiving means, said movement of the reflecting assembly being in response to an external force of a preselected minimum magnitude being applied to the reflecting member and said second position of the reflecting member being located in a direction of the applied force lying along said plane.