Abstract:
A culling device for a conveyance apparatus which culling device includes cross transport apparatus carrying flexible fingers which have selected strength, position and speed to cull out selected objects being conveyed. In particular, elongated objects may be conveyed and culled.

Description:
BACKGROUND OF THE INVENTION 
     Strip edge separating and strip picking apparatus is old (U.S. Pat. Nos. 3,017,909; 3,101,755; and 3,139,125). Other conveying systems have used moving fingers for conveying purposes (U.S. Pat. No. 2,499,694) and it has been suggested that conveyor fingers be spring-loaded to avoid breakage of the fingers (U.S. Pat. No. 1,358,167). 
     Strip edge conveyor systems have not provided means for automatically and selectively removing lighter objects while not removing heavier objects. 
     SUMMARY OF THE INVENTION 
     Broadly, the present invention is an apparatus for culling strip objects while such objects are being conveyed along with larger or heavier elongated objects. The apparatus includes flexible fingers mounted on one or more transverse carriers moving in opposite directions which fingers engage and move the strips off either side of the conveyor while engaging but not removing larger and heavier objects. 
     It is a feature that the fingers are adjustable vertically to vary the forces including lateral forces they exert on the objects being conveyed. The higher the spring is adjusted above the plane of the workpiece, the more mechanical advantage the workpiece has on the spring, resulting in less force on the workpiece. Conversely, the shorter the spring, the more force is exerted on the workpiece. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the culling apparatus of the present invention including cross belt culling units; 
     FIG. 2 is a partial elevational view of a cross chain culling unit; 
     FIG. 3 is a partial elevational side view of a cross chain culling unit engaging a board; 
     FIG. 4 is a partial elevational view of a cross chain culling unit culling a strip object; 
     FIG. 5 is an elevational view of a finger holder; 
     FIG. 5a is a perspective view of an alternative finger holder with the finger deflected forward; and 
     FIG. 5b is a view similar to FIG. 5a with the finger in a curved recess. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to FIGS. 1-5b, gang ripsaw cut board and strip conveyor system 8 conveys cut board objects using driven rollers 10, 11, 12 in direction A. Upper surfaces of driven rollers 10-12 form a conveying plane P. Cut board conveyor 8 conveys boards 16 of substantial width, length and weight and also conveyor strips 17 of less width, length or weight. Elongated boards 16 with front ends 16a and elongated strips 17 exit a cutter (not shown) pass over lip 19 and are thereafter conveyed on and by rollers 10, 11, and 12. Strips 17, as shown, are about 1/2 inch in width but strips of varying width, height and length may be culled using the present invention. 
     Mounted across conveyor 8 in spaced-apart manner are right cross cull units 20 and left cross cull units 21 each comprising driven sprockets 22a-c and driven sprockets 23a-c. Sprockets 23a-c are mounted on drive shaft 24 turned by motor M 1 . Sprockets 22a-c turn on shaft 26 driven by motion M 2 . Each unit 20, 21 also includes a chain 27 carrying one or more blocks 28 each having an upstanding finger 30 mounted in slot 29. Units 20, 21 also include inner layer idler sprockets 25a and inner small idler sprockets 25b. Sprockets 25b are of reduced diameter so that units 23a,b present fingers 30 at varying heights above plane P as they travel from the inner center where fingers 30 extend a lesser distance above plane P to the edge area where fingers 30 extend a greater distance above plane P. Finger 30 extension, so varied, makes the culling action less aggressive in the center and thus provides for better culling. 
     Turning to FIG. 5, angled slot 29 accommodates movement of finger 30 as deflected by the leading edges 16a of boards 16 as they advance through system 8. Fingers 30 are preferably a relatively stiff coil spring but other deflectable elements may be used. The amount the fingers 30 extend above blocks 28 varies the force the fingers 30 apply to boards 16 and strips 17. The heights of fingers 30 are adjustable using set screws 31. Adjustment is accomplished by loosening each nut 32 and after finger adjustment retightening nut 32. The speed of fingers 30 also effects culling. 
     Turning to FIG. 3 and 4, it is seen that finger 30 deflects under board 16 without moving board 16 left or right any significant distance but when finger 30 engages the lighter strip 17 it urges it off the conveyor. Fingers 30 are bendable under loads applied by boards 16 but not significantly bendable under loads applied by strip 17 so that the paths of boards 16, as they are conveyed, are not substantially altered by fingers 30 while strips 17 are culled out and removed, left or right, from conveyor 8. 
     Turning finally to FIGS. 5a, 5b, an alternative block 28&#39; is shown having block cavity 29&#39; which includes forward portion 29a and curved side portion 29b. When a board end 16a engages finger 30 it is deflected out of portion 29b and forward into cavity portion 29a where it is readily bent forward (FIG. 5a). When board 16 or strip 17 resists finger 30 sideways movement it keeps finger 30 in cavity portion 29b which effectively shorten the length of finger 30 making the finger stiffer with greater deflecting power (FIG. 5b). Thus, finger 30 remains in portion 29b except when acted on by the front end 16a of a board 16.