System and method for externally controlled spacing of self propelled vehicles along a rail

A vehicular system comprising,

• a rail extending in a predetermined path;
• at least two vehicles contacting said rail and guided thereby for in-line motion along said path in a forward direction, said vehicle spaced in forward and rear relation to each other;
• an elongate stationary cam channel connected to said rail extending parallel to said predetermined path, said cam channel having a U-shaped cross-section with a base surface and sidewalls;
• an elongate cam member received within said cam channel extending therealong, said cam member having an outer cam edge spaced from said base surface of said cam channel, said cam edge rising and falling in an inward and outward direction perpendicular to the length of said cam in a predetermined manner along its length between a base level and a peak level spaced a maximum distance outwardly from said base level;
• each said vehicle including,
• variable speed driving means for driving said vehicle along said path at varying speed controlled by a control signal;
• a cam follower movably mounted on said vehicle biased into sliding contact with said cam edge;
• a transducer connected to said cam follower for providing said control signal to said driving means, said transducer varying said control signal in response to the spacing of said cam follower from said base level to cause the speed of said vehicle to be decreased in response to increase in spacing of said cam follower away from said base level and vice versa;
• an elongate tail connected to said vehicle extending rearwardly therefrom, said tail having an outer longitudinal edge;
• a tail guide channel mounted alongside said cam channel, said tail guide channel being of generally U-shaped cross-section having side walls and a base surface, said tails being slidably received within said tail guide channel for movement parallel to said base level of said cam edge with said outer edges of said tails positioned alongside said cam edge and with at least a projecting portion of each said tail outer edge spaced a greater distance from said base level than the adjacent regions of said cam edge, said cam followers positioned to contact both said cam edge and said outer edges of said tails;
• whereby, if said vehicles come close enough together for said cam follower of the rear said vehicle to be moved further away from said base surface of said cam channel by the projecting portion of said outer edge of said tail of the forward said vehicle than said cam follower of the forward said vehicle resting on said cam edge, said transducer of the rear said vehicle signals said driving means of the rear said vehicle to move at a speed no faster than the speed of said forward vehicle.

A tail for use in a vehicular system for avoiding collision between forward and rear vehicles moving in-line along a rail, wherein the speed of each vehicle is controlled by a stationary cam which extends alongside the rail with each vehicle having a movably mounted cam follower which slidably contacts an edge of the cam, each vehicle being driven by a drive motor at a speed determined by a transducer which acts to control the drive motor in response to the movement of the associated cam follower on the edge of the cam to cause each vehicle to be driven at a speed responsive to the position of its cam follower on the cam edge, the tail being attached to at least the forward vehicle and pulled thereby along a tail guide channel extending in a path alongside the cam, the tail of the forward vehicle elevating the cam follower of the rear vehicle from the cam edge when the vehicles come close enough together, the raising of the cam follower of the rear vehicle from the cam edge causing the transducer of the rear vehicle to control the rear vehicle to move no faster than the speed of the forward vehicle thereby avoiding collision, the tail comprising,

• a flexible sheet-like body extending in a lengthwise direction, said body having,
• an elongate base edge supporting said body for sliding motion along the tail guide channel, and;
• an outer edge spaced in opposition to said base edge, said outer edge having a sloped region extending from a position adjacent the forward end of said tail to the rear end thereof, said sloped region extending from a maximum spacing from said base edge adjacent the forward end convergently towards the rear end, said base edge being supported by the tail guide channel such that at least a portion of said sloped region of said outer edge projects beyond the edge of the cam.

A vehicular system comprising,

• a rail extending in a predetermined path;
• at least two vehicles contacting said rail and guided thereby for in-line motion along said path in a forward direction, said vehicles spaced in forward and rear relation to each other;
• an elongate stationary cam connected to said rail extending parallel to said predetermined path, said cam having a cam edge which provides sensible information related to the speed at which a vehicle traveling along the track should travel varying in a predetermined manner along the length of the path;
• each said vehicle including,
• variable speed driving means for driving said vehicle along said path at varying speed controlled by a control signal;
• sensing means mounted on said vehicle for sensing the sensible information provided by said cam and providing said control signal to said driving means to cause it to drive said vehicle at a speed determined by the sensible information provided by said cam;
• an elongate tail connected to said vehicle extending rearwardly therefrom, said tail, along its length, having an outer edge also provided with sensible information sensible by said sensing means;
• a tail guide guiding each said tail for movement parallel to said base level with said outer edge of said tail positioned alongside said cam edge;
• said sensing means of the rear said vehicle also sensing the sensible information provided on said tail of the forward said vehicle when said rear vehicle approaches said forward vehicle closely enough for said sensing means of the rear said vehicle to be positioned over said tail of the forward said vehicle, said sensing means comparing the information sensed from the region of said cam edge adjacent said rear vehicle with the information sensed from said tail of said forward vehicle for providing a control signal to said driving means of the rear said vehicle to move at a speed no faster than the speed of the forward said vehicle.

A method of avoiding collision between forward and rear vehicles moving in-line along a rail, wherein the speed of each vehicle is controlled by a stationary cam which extends alongside the rail with each vehicle having a movably mounted cam follower which slidably contacts an edge of the cam which rises and falls in an inward and outward direction perpendicular to its length in a predetermined manner therealong between a base level and a peak level spaced at a maximum distance outward from the base level, each vehicle being driven by a drive motor at a speed determined by a transducer which controls the drive motor in response to the movement of the associated cam follower on the edge of the cam thereby causing each vehicle to be driven at a speed inversely responsive to the spacing of its cam follower from the base level, the method comprising the steps of,

• providing each vehicle with a tail which extends behind the vehicle and is pulled along by it;
• guiding the tails for movement alongside the cam as the vehicles move along the rail;
• contouring each tail to have an outer edge facing outwardly in the same direction as the cam edge with at least a projecting portion of the outer edge of each tail spaced a greater distance from the base level than the cam edge;
• and
• if the vehicles come close enough together for the cam follower of the rear vehicle to be moved further away from the base level by the projecting portion of the outer edge of the tail of the forward vehicle than the cam follower of the forward vehicle resting upon the cam edge, causing the transducer of the rear vehicle to signal its drive motor to move the rear vehicle no faster than the forward vehicle.