Method and apparatus for determining elevation

Abstract

A light reference system for generating .[.a collimated beam of light and converting.]. and projecting .[.the same as.]. a relatively intense fan-shaped or diverging plane of light from an operator manipulatable device on a machine or a vehicle to an object or opening which may be positionally referenced to the device in a selected predetermined relation by operator control of the machine or vehicle and manipulatable device, thus enabling the operator to observably locate a sharply defined resulting line of light so as to establish such selected relation. The light reference system is capable of a number of different embodiments or forms, a few of which are disclosed herein. An exemplary embodiment of the machine or vehicle with which such a system is combined herein is of a fork lift truck vehicle on which the light reference system in various forms is mounted on the elevatable load handling device or fork carrier for generating .[.a collimated beam of light and for converting the same into.]. a flat plane of diverging light, referred to .[.usually.]. .Iadd.sometimes .Iaddend. herein as a "fan-shape" of light, having abrupt demarcation in intensity and projected as a relatively intense operator observable line of light to any selected object, such as to a pallet in an elevated bin of a storage rack, in a predetermined attitude with respect to the load handling device such as the fork of a fork truck. Also disclosed is an embodiment which projects an image or visual reference in the form of a line of light, generated by a scanning laser beam, and projected on surfaces in the path of the projected light such as a pallet as recited above.

I claim: 
     
       1. In a vehicle .Iadd.maneuverable by an operator .Iaddend.having a .[.manipulatable.]. load handling device .Iadd.maneuverable both in elevation and in attitude.Iaddend., a light optical means mounted on the handling device being so constructed and arranged as to .[.provide a substantially collimated light beam and to.]. project .[.said.]. light .[.beam.]. from said load handling device as a diverging plane of light collimated in one dimension and in a predetermined attitude in relation to the load handling device such that a visual reference of .Iadd.both .Iaddend.the .[.position.]. .Iadd.elevation and attitude .Iaddend.of the load handling device appears in the form of a distinctly perceivable line of light on surfaces in the path of the projected diverging plane of light .Iadd.both parallel and angular to the direction of travel of the vehicle.Iaddend.. 
     
     
       2. A device as claimed in claim 1 wherein the light optical means is mounted on the load handling device inside of rigid enclosing structure in a manner which protects the light optical means from damage during relatively rough load handling operations. 
     
     
       3. A device as claimed in claim 1 wherein said light optical means is adapted to project light through a plane having diverging edges. 
     
     
       4. A device as claimed in claim 2 wherein said load handling device comprises an elevatable carriage of a lift truck, and .Iadd.at least a portion of .Iaddend.said enclosing structure comprises an elongated hollow beam means secured lengthwise of one side of the carriage and having an opening through which the .[.collimated.]. light .[.beam.]. is projected as said diverging plane of light. 
     
     
       5. A device as claimed in claim 2 wherein said .[.collimated.]. light .[.beam.]. travels longitudinally of said enclosing structure .Iadd.as a collimated beam.Iaddend., and means is provided for redirecting and projecting said .Iadd.collimated .Iaddend.light beam as said diverging plane of light through an opening formed in said rigid enclosing structure. 
     
     
       6. A device as claimed in claim 5 wherein the source of said light beam is located in the enclosing structure in longitudinally spaced relation to the opening through which is projected said plane of light. 
     
     
       7. A device as claimed in claim 4 wherein said carriage is a fork carriage, said enclosing structure is secured at one side only of the fork carriage, and said opening is dimensioned such that the diverging edges of said plane of light are adapted to subtend an angle so that the line of light as projected on a surface adjacent the lift truck indicates the elevation and attitude of the fork carriage at both sides thereof. 
     
     
       8. A device as claimed in claim 4 wherein the location of said line of light is an operative visual reference of both the elevation and tilt attitude of said carriage. .[.9. A device as claimed in claim 1 wherein said light beam is projected in a diverging plane transverse to the direction of movement of the load handling device on the vehicle so that the elevation and attitude of the handling device may be visually perceived as a line of light on surfaces both parallel and angular to said 
     
     
        direction of travel..]. 10. A device as claimed in claim 1 wherein said diverging plane of light is projected both sideways and forwardly of the 
     
     
        load handling device. 11. A device as claimed in claim 1 wherein said 
     
     
        projected plane of light is substantially of a fan-shape. 12. A device as claimed in claim 1 wherein .Iadd.said light optical means provides a substantially collimated light beam and .Iaddend.a conical reflector 
     
     
        converts said collimated light beam to said diverging plane of light. 13. A device as claimed in claim .[.9.]. .Iadd.1 .Iaddend.wherein .[.the vehicle is a maneuvering vehicle the load handling device of which is maneuverable in elevation as well as with the vehicle,.]. said line of light .[.being.]. .Iadd.is .Iaddend.a continuous visual reference on the said surfaces facilitating precise operator's control of the load handling device during maneuvering of the vehicle, whereby to reduce the requirement for operator's depth perception other than by said visual 
     
     
        reference. 14. An apparatus as claimed in claim 1 wherein .[.the load handling device is maneuverable both with the vehicle and in elevation, the projected line of light being projected in a plane substantially transverse of the direction of movement of the load handling device so that the elevation and attitude thereof may be visually perceived as a line of light on surfaces both parallel and angular to the load handling device,.]. tilting of the load handling device from a horizontal position .[.causing.]. .Iadd.causes .Iaddend.the line of light to be projected onto a substantially vertical surface which is substantially parallel to the direction of travel of the load handling device at an angle to the horizontal which indicates to the operator the approximate angle and direction of tilt of the load handling device, and turning of the load handling device from such a parallel to a transverse relation to said vertical surface .[.causing.]. .Iadd.causes .Iaddend.the line of light to reflect as a substantially horizontal line from the transverse surface which indicates both the attitude and elevation of the load handling 
     
     
        device in relation thereto. 15. .[.An apparatus for mounting on a maneuverable.]. .Iadd.In a .Iaddend.load handling device .Iadd.mounted on a maneuverable vehicle and elevatable thereon, an apparatus .Iaddend.comprising a rigid housing, means mounted in the housing for producing a substantially collimated light beam which is projected inside of the housing, an opening in said housing, reflector means in said housing mounted in a predetermined relation both to said light beam means and to said opening, said reflector means being in the line of projection of said light beam and being adapted to project said light beam through said opening and outside of said housing, said opening being of such predetermined size and location relative to said reflector means as to permit said light beam to be projected outside of said housing in a predetermined attitude in relation to said load handling device and in a manner to produce a visual reference which appears in the form of a distinctly perceivable elongated line of light on .[.a surface.]. .Iadd.surfaces .Iaddend.in the path of the projected light beam, .[.said line of light defining the position of the load handling device relative to said surface.]. .Iadd.the projected line of light being projected in a plane substantially transverse to the direction of movement of the load handling device so that the elevation and attitude thereof may be visually perceived as said line of light on surfaces both parallel and angular to the load handling device.Iaddend.. .[.16. An apparatus as claimed in claim 15 wherein the load handling device is mounted on a vehicle and is maneuverable both with the vehicle and in elevation, the projected line of light being projected in a plane substantially transverse to the direction of movement of the load handling device so that the elevation and attitude thereof may be visually perceived as a line of light on surfaces both 
     
     
        parallel and angular to the load handling device..]. 17. .[.An apparatus.].  .Iadd.A device .Iaddend.as claimed in claim .[.16.]. .Iadd.32 .Iaddend.wherein tilting of the load .[.holding.]. .Iadd.handling .Iaddend.device from a horizontal .[.portion.]. .Iadd.position .Iaddend.causes .[.a.]. .Iadd.said .Iaddend.line of light to be projected onto a vertical surface parallel to the direction of travel of the vehicle at an angle to the horizontal which indicates to the operator the angle 
     
     
        and direction of tilt of the load handling device. 18. .[.Apparatus.]. .Iadd.A device .Iaddend.as claimed in claim 17 wherein turning the load handling device from a parallel to a transverse relation to said vertical surface causes the line of light to reflect as a substantially horizontal line from the transverse surface which indicates both the attitude and 
     
     
        elevation of the load handling device in relation thereto. 19. An apparatus as claimed in claim 15 wherein said reflector means is supported on a fulcrum and is adapted to be mounted on triangularly related 
     
     
        adjustment means for tilting the reflector means on the fulcrum. 20. An apparatus as claimed in claim 15 wherein said reflector means is supported on a fulcrum and is adapted to be mounted on adjustment means for tilting the reflector means on the fulcrum in any one of a plurality of selected directions to adjust the position of the line of light on said 
     
     
        .[.surface.]. .Iadd.surfaces.Iaddend. . 21. Apparatus as claimed in claim 15 wherein said light beam means includes a light source located at the focal point of a reflector for producing said light beam, said reflector means projecting said light beam as a diverging plane of light which appears as said line of light on such .[.a surface.]. 
     
     
        .Iadd.surfaces.Iaddend.. 22. Apparatus as claimed in claim 15 wherein said light beam means provides a laser beam, and said reflector means projects said laser beam as a scanning beam forming a diverging plane of light such that it is visually perceived as said line of light on .[.such a 
     
     
        surface.]. .Iadd.such surfaces.Iaddend.. 23. Apparatus as claimed in claim 15 wherein said light beam means includes a light source, reflector, lens means and cropper means intermediate said light source and lens means for interrupting an area of peripheral light rays emanating from the light source toward said lens means all of predetermined design and spacing to .[.produce.]. .Iadd.focus .Iaddend.said substantially collimated light beam, said reflector means projecting said collimated beam through said 
     
     
        opening as a diverging plane of light. 24. Apparatus as claimed in claim 15 wherein said reflector means receives said beam of light and projects it through said opening in a diverging plane collimated in one dimension and adapted to reflect from said .[.surface.]. .Iadd.surfaces .Iaddend.as 
     
     
        said line of light. 25. Apparatus as claimed in claim 15 wherein said rigid housing is of tubular or multi-sided elongated construction said light beam being directed lengthwise thereof and said reflector means being spaced longitudinally .[.thereof.]. .Iadd.of the source of said light beam .Iaddend.for receiving said light beam in the vicinity of said opening and for redirecting and reforming said light beam to project through said opening so as to form said visually perceivable line of 
     
     
        light. 26. Apparatus as claimed in claim 25 wherein said light beam is a laser beam and said reflector means projects said laser beam as a scanning 
     
     
        beam in a diverging plane. 27. .[.Apparatus.]. .Iadd.A device .Iaddend.as claimed in claim .[.25.]. .Iadd.32 .Iaddend.wherein said light .[.beam.]. is projected as a flat diverging plane of light .[.which is reflected as 
     
     
        said line of light from said surface.].. 28. Apparatus as claimed in claim 22 wherein said reflector means includes a biased motor driven reflecting 
     
     
        surface for projecting said laser beam as a scanning beam. 29. .[.Apparatus.]. .Iadd.A device .Iaddend.as claimed in claim .[.15.]. .Iadd.32 .Iaddend.wherein .[.said.]. .Iadd.such a parallel .Iaddend.surface reflects a sloping line of light if the load handling device is in a non-horizontal attitude, the slope of the line of light 
     
     
        increasing in proportion to the angle of said device from horizontal. 30. .[.Apparatus.]. .Iadd.A device .Iaddend.as claimed in claim .[.15.]. .Iadd.32 .Iaddend.wherein said load handling device is a tiltable and elevatable fork carriage of a lift truck, and said line of light as reflected and perceived by an operator provides a direct visual reference to the angle of tilt of the fork either rearwardly or forwardly and to the 
     
     
        elevation of the fork. 31. Apparatus as claimed in claim 21 wherein said light source comprises a high intensity arc lamp. .Iadd. 32. In a vehicle maneuverable by an operator having a load handling device maneuverable both in elevation and in attitude, a light optical means mounted on the handling device being so constructed and arranged as to project light from said handling device so that it traverses and is projected in a diverging plane substantially transverse to the direction of movement of the load handling device with the vehicle, the light being collimated in at least one dimension and in a predetermined attitude in relation to the handling device providing for the operator a visual reference of both the elevation and attitude of the handling device in the form of a distinctly perceivable line of light on surfaces in the path of said diverging plane both parallel and angular to the direction of travel of the vehicle. .Iaddend..Iadd. 33. An apparatus as claimed in claim 32 wherein said light optical system includes an incandescent light as a source of light. .Iaddend..Iadd. 34. An apparatus as claimed in claim 33 wherein said light optical system includes means interrupting an area of peripheral light rays emanating from the incandescent light for focusing the light. .Iaddend..Iadd. 35. An apparatus as claimed in claim 34 wherein said interrupting means is a cropper means. .Iaddend..Iadd. 36. An apparatus as claimed in claim 34 where said light optical system includes a lens, said interrupting means being located intermediate the incandescent light and the lens. .Iaddend..Iadd. 37. An apparatus as claimed in claim 1 wherein said light optical system includes an incandescent light as a source of light and means interrupting an area of peripheral light rays emanating from the incandescent light for focusing the light. .Iaddend. .Iadd.38. An apparatus as claimed in claim 14 wherein said light optical system includes an incandescent light as a source of light. .Iaddend. .Iadd. 39. An apparatus as claimed in claim 38 wherein said light optical system includes means interrupting an area of peripheral light rays emanating from the incandescent light for focusing the light. .Iaddend..Iadd. 40. An apparatus as claimed in claim 39 wherein said light optical system includes a lens, said interrupting means being located intermediate the incandescent light and the lens. .Iaddend.