Abstract:
An apparatus for rotating elongated members of rectangular cross section, such as board lumber, is disclosed. The apparatus includes a pair of conveyors arranged so that the boards will cascade from the end of one conveyor onto the other conveyor by force of gravity, rotating in the process. A dampening mechanism to reduce the impact caused by the fall is also disclosed. The dampening mechanism allows the members to be delicately balanced on any side. After an inspection, the boards are turned again to position them for final processing. This second rotation is performed by halting the leading edge ofthe boards, at either the top or bottom, and propelling the opposite edge forward with a rubber wheel.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates, generally, to a device for handling lumber. 
     2. Description of Related Art 
     In the manufacture of wooden I-beams, the rectangular wood flanges may be cut by rip saw from laminated billets. It is desirable to inspect the laminations at each cut prior to final assembly in order to assure the quality of the products to be made from the flanges. From the cutting process to positioning for final assembly, the flanges must be turned twice to facilitate the inspection process. By turning the flanges, each fresh cut is made visible. Because the flanges can be longer than 80 feet, turning the flanges manually is difficult and undesirable. 
     The simplest way of performing the first turn automatically is to use gravity in combination with a pair of conveyors. A conveyor apparatus is generally required as part of the manufacture and inspection process regardless of the technique used to turn the flanges. By adding a second conveyor and positioning it below the end of the first, a cascade is created. When the flanges reach the end of the first conveyor, they will follow the rounded end of the conveyor pulley and fall to the second conveyor having rotated approximately ninety degrees. Of course, the conveyance speed and the height difference of the conveyors must be set to suitable levels to achieve proper rotation. This simple cascade method works well when the flanges have an approximately square cross-section. 
     The previously described method is not sufficient when the aspect ratio of the flanges is significantly high. If the width-to-thickness ratio of the flanges is too great, the relatively narrow base upon which to flange must balance, coupled with the bounce of the flange upon impact, causes many of the flanges to fall onto their wide side. Generally the flanges fall forward due to their angular and linear momentum. 
     The second turn, which places the flanges into their final position for assembly, is another practical difficulty involved in the preparation and inspection process. Some of the flanges need to be returned to their original orientation while others need to be turned an additional ninety degrees. 
     Several mechanisms exist for reorienting objects of varying shape during a manufacturing process. However, there is no known device for simply and reliably rotating elongated members of varying aspect ratio about their longitudinal axis. 
     What is needed is a simple and inexpensive system for performing the turns. The first element of such a system is a device for turning flanges onto their narrow side which is more reliable than a simple cascade system. The second element returns the flanges to their original orientation or alternatively turns the flanges an additional ninety degrees. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a mechanism by which elongated members can be automatically rotated during a linear translation. 
     It is another object ofthe present invention to provide a mechanism capable of reliably performing the rotation on members of diverse cross-sectional aspect ratios. 
     It is another object of the present invention to provide a flange turning device which is relatively inexpensive. 
     These and other objects are achieved, according to the invention, by a device for rotating elongated objects of approximately rectangular cross-section about the longitudinal axis. The device includes a first turn section and a second turn section. 
     The first turn comprises two conveyor units arranged to allow a cascade effect as the members fall from the end of the first conveyor to the second conveyor. The members, positioned with their length generally perpendicular to the direction of conveyance, naturally rotate about their longitudinal axes as they fall. A dampening mechanism dissipates a portion of the energy of the members gained during the fall and places the members onto the second conveyor. 
     In one embodiment the dampening mechanism includes at least one rotating portion which catches the member in mid-fall and, through rotation, places the member on the second conveyor. The rotating portion of the mechanism is dampened to allow for smooth placement of the member onto the second conveyor. A spring returns the rotating portion back to its starting position after the flange member has been carried away. 
     The addition of a second rotating member to the dampening mechanism provides even further benefit. With a single rotating member, the member pushes up against the flange even after the flange has been placed on the second conveyor. This action is due to the spring return mechanism and can cause a significant force against the rear corner of the flange as the flange passes off of the rotating member. It can even cause the flange to fall forward onto its wide side. Disclosed herein is the use of a second rotating member which pushes the flange forward off of the first rotating member so that the first rotating member exerts no force on the flange once it has reached the second conveyor. 
     Also disclosed herein is a mechanism which accomplishes the desired task without the use of rotating members. In this embodiment, the dampening mechanism includes a horizontally positioned member translatable along its vertical axis and dampened by a piston-cylinder device. A second member powered by a fluidic connection with the first piston-cylinder device can be added to push the flange, imparting some forward momentum before the flange makes contact with the second conveyor. 
     The second turn comprises an upper and a lower section. Flanges to be turned back to their original orientation proceed to the upper section, while flanges to be turned an additional ninety degrees are directed to the lower section. The two sections operate on the same principle. The flanges are stopped on the second conveyor by stop pins to ensure the flanges enter the turner oriented perpendicular to the direction of conveyance. When the stop pins are removed the flanges approach the end of the second conveyor. 
     In the upper section a dog halts the top edge of each flange while an elastomeric wheel propels the bottom edge forward. The flange then drops away from the dog, falls on the wheel, and moves onto the discharge conveyor with the original surface facing up. In the lower section, a trip point halts the bottom edge of each flange while an elastomeric wheel propels the upper edge forward. The flange then falls onto the discharge conveyor with the desired orientation. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of the invention. 
     FIG. 2 is a side view of an embodiment of the first turn. 
     FIG. 3 is an isometric view of the embodiment shown in FIG.  2 . 
     FIG. 4 is a side view of another embodiment of the first turn. 
     FIG. 5 is a side view of a simplified version of the embodiment in FIG.  4 . 
     FIG. 6 is a side view of the second turn, upper section. 
     FIG. 7 is a side view of the second turn, lower section. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 is a full view of the invention. It shows the process that the flanges go through as they are turned onto their narrow side and then turned back again to their wide side. The first turn is shown on the right, and the second turn is shown on the left. Second conveyor  12  is shown in the middle of the drawing. Both first conveyor  11  and second conveyor  12  can be pivoted about their respective right sides. First conveyor  11  is adjusted by first conveyor arm  70  to provide various vertical displacements between the conveyors to accommodate different flange sizes, as discussed below. Second conveyor  12  is adjusted by second conveyor arm  71  to control the exit path of the flanges. Reject conveyor  47  is shown on top at the left, upper discharge conveyor  45  at the middle, and lower discharge conveyor  46  at the bottom. Both conveyors are fixed to frame  72 . 
     One embodiment of the first turn section of the invention is shown in FIG.  2  and FIG.  3 . First conveyor  11 , second conveyor  12 , first conveyor pulley  6 , and second conveyor pulley  7  are shown. Vertically positioned cylinder  30  houses a piston (not shown) and piston rod  36 . Foot  34  is supported by piston rod  36  such that foot  34  is translatable along an approximately vertical axis, dampened in the downward direction by fluid action in cylinder  30 . Also shown in FIG.  2  and FIG. 3 is a second, horizontally positioned cylinder  31  which houses a piston (not shown) and piston rod  37 . Piston rod  37  is attached to pusher  35 , translatable along an approximately horizontal axis. 
     Foot  34  must be able to pass below the plane of second conveyor  12  in order to deposit flange  32  onto second conveyor  12 . This potential problem of interference by the conveyors applies to all embodiments ofthe invention. Several solutions are disclosed below for the embodiments of FIG.  2  and FIG. 3, and these solutions also apply in a general sense to the other embodiments. 
     One solution is to utilize conveyors which consist of chains circling sprocket conveyor pulleys as opposed to a continuous sheet of material stretched across the width of the conveyor. This chain type of conveyor is depicted in FIG.  2 . As shown in the figure, the area between the chains remains open providing room for the dampening apparatus. Furthermore, with this chain design one can easily adjust the height difference between the conveyors. The vertical spacing can even be set to a level less than the diameter of either pulley simply by using conveyors of different widths or establishing a slight horizontal offset between the conveyors. FIG. 2 shows a horizontal offset. 
     Another solution to the problem of conveyor interference with the dampening apparatus is to use multiple instances of the dampening mechanism and place them outside of the conveyors. To use this solution the flanges must be greater in length than the conveyors are wide so that the flanges will contact both dampening mechanisms. In the embodiment of FIG. 2, this solution requires that foot  34  comprise two surfaces, one surface positioned on each side of second conveyor  12  capable of supporting flange  32  after flange  32  falls from the end of first conveyor  11 . The two surfaces of foot  34  may be connected at a point below second conveyor  12  and from there connected to piston rod  36 . Alternatively, a cylinder may be used on each side of second conveyor  12 , each cylinder supporting its own foot. Numerous other geometries exist which would accomplish the task. For instance, one or more cylinders could be mounted upside-down above second conveyor  12 , provided the foot support members did not interfere with flange  32 . 
     Referring again to FIGS. 1 and 2, it is important to note that horizontal cylinder  31 , air line  33 , and pusher  35  are optional features of the invention. Vertical cylinder  30  is capable of providing the necessary dampening effect with the use of a restriction through which fluid is moved. For the single-cylinder embodiment, the turning process begins when flange  32  reaches end of first conveyor  11 . Flange  32  follows the curvature of first conveyor pulley  6 , rotating approximately ninety degrees, until flange  32  contacts foot  34 , which is in its starting position. With the cylinder acting as a damper, the foot  34  travels downwardly toward second conveyor  12 . As foot  34  passes below the plane of second conveyor  12 , flange  32  makes contact with second conveyor  12  and flange  32  carried along with second conveyor  12 , rotated with respect to its previous position on first conveyor  11 . The dampening effect of cylinder  30  prevents a large impact force due to the gravitational acceleration of flange  32 . 
     Foot  34 , which is biased, then returns to its starting position ready to receive another flange  32 . The bias for foot  34  can be created in numerous ways. The simplest mechanism to accomplish this is a spring housed in cylinder  30 . The actual location and type of spring is of course not important to the spirit of the invention, as long as foot  34  is directly or indirectly biased to return to its starting position. A coiled or flat spring, located within the cylinder or without, would all be sufficient. Another possibility to create the bias is to move air during the downstroke into a reservoir that would become somewhat pressurized. The pressurized air in the reservoir would then expand when the weight of flange  32  was removed from foot  34 , pushing piston rod  37  and foot  34  back to the starting position. Others skilled in the art will know of other means for biasing foot  34 . 
     The performance of this embodiment can be improved with the addition of horizontally positioned cylinder  31  as shown. Cylinder  31  houses a piston (not shown) and second piston rod  37 . At the end of second piston rod  37  is pusher  35 . Pusher  35  comprises a surface approximately perpendicular to that of foot  34 . First cylinder  30  and second cylinder  31  communicate through fluid line  33 . This communication causes an extension of one piston rod during retraction of the other, and vice versa. 
     During the turning process, flange  32  leaves first conveyor  11  and contacts foot  34 . Flange  32  exerts a downward force on foot  34  due to the weight and momentum of flange  32 . This downward force causes first piston rod  36  to recede into first cylinder  30 . The resultant pressure increase in first cylinder  30  is transferred along fluid line  33  to second cylinder  31 . The pressure created in the second cylinder  31  causes second piston rod  37  to extend, bringing pusher  35  into contact with flange  32 . As flange  32  continues to move downwardly with foot  34 , pusher  35  exerts a force against flange  32 . This force exerted by pusher  35  imparts momentum to flange  13  in the general direction of the movement of second conveyor  12 . Thus, flange  32  slides along foot  34  until foot  34  is below the plane of second conveyor  12 . 
     Because the relative horizontal velocities of flange  32  and second conveyor  12  are lessened through the action of pusher  35 , there is less of a moment on flange  32  imparted at the contacting surface of flange  32  and the second conveyor  12 . This reduction in the moment acting on flange  32  leads to a more reliable turn, with fewer flanges falling over backward as they contact second conveyor  12 . 
     Another embodiment of the first turn section of the invention is shown in FIG.  4 . First conveyor  11  and second conveyor  12  are positioned as in the previous embodiments. Additionally, foot  8  and pusher  9 , which partially comprise the dampening mechanism of this embodiment, are shown in their starting position, rotatably fixed to foot pivot point  4  and pusher pivot point  2 , respectively. A typical flange is depicted at various stages of the turning process. Flange  13  on first conveyer  11  prior to being turned, flange  14  at the moment of contact with foot  8 , and flange  15  on second conveyer  12  after being turned demonstrate the positional changes a flange undergoes during the turning process. 
     In the embodiment shown in FIG. 4, foot  8  and pusher  9  rotatably communicate through link  16  attached to foot  8  at foot linkage point  5  and pusher  9  at pusher linkage point  3 . Link  16 , foot  8 , and pusher  9  together form a four-bar linkage constrained to one degree of freedom. The moved position, shown as a dotted line, indicates the position of foot  8 , pusher  9 , and link  16  at the end of the stroke. In this embodiment, foot  8  is biased to move clockwise. Any suitable biasing means may be used, as detailed above. 
     The turning process begins as flange  13  reaches the end of first conveyor  11 . Flange  13  follows the curvature of first conveyor pulley  6  and begins to rotate as it falls from first conveyor  11 . The side of flange  14  that is to be placed on second conveyor  12  contacts the upper face  18  of foot  8  at or near the time that the side of flange  14  that was in contact with first conveyor  11  contacts the front face  19  of pusher  9 . The weight and momentum of flange  14  imparts counterclockwise rotation to foot  8 . As foot  8  rotates and flange  14  moves downwardly, pusher  9  also rotates counterclockwise, maintaining support of flange  14 . 
     As is evident from the moved position shown as a dotted line in FIG. 4, when foot  8  pusher  9  members rotate, the flange-supporting surfaces of each slide relative to one another. This sliding acts to push flange  14  along foot  8  in the direction of second conveyor&#39;s  12  motion during the downstroke. It is best if the four-bar is designed such that, at the end of the stroke, pusher  9  has completely pushed flange  14  off of foot  8 . 
     A simplified version of this embodiment is shown in FIG.  5 . Foot  8  and pusher  9  ofthe previous embodiment are combined to make one foot member  17 . The member rotates about single pivot point  20  and is dampened by damper  10  as before. Because there is no four-bar linkage, this embodiment does not push flange  14  off of foot  17  during rotation. Because foot  17  is biased to rotate clockwise, this will lead to foot  17  pushing up against flange  14  while flange  14  is carried away on second conveyor  12 . The bias must be set to a level that will not cause flange  14  to flip over forward as it passes off of foot  17 . 
     The speed of the two conveyors is important to achieving good results. First conveyor  11  should travel at 20 to 80 feet per minute, depending on the size of the flanges being processed. Second conveyor  12  should generally be set at a speed near to that of first conveyor  11 . A speed offset may be desirable when non-square flanges are used. If a rectangular flange is being turned from its wide side onto its narrow side, second conveyor  12  should be set to a lower speed than first conveyor  11  to achieve the same spacing between flanges on second conveyor  12  as that on first conveyor  11 . 
     The vertical spacing between the conveyors is also important, and it must be varied depending on the size of the flanges being turned. For example, for a flange the size of a two-by-four, or 1.5 inches by 3.5 inches, second conveyor  12  should be 3.75 to 4.75 inches below first conveyor  11 . One quarter to one and one quarters of an inch more than the height of the flange is generally a good spacing, although for larger flanges it may be found that more spacing is desirable. 
     FIG. 6 shows the upper section of the second turn. Second conveyor  12 , shown at the left, carries the flanges into stop pins  40 . Upon the removal of stop pins  40 , the flanges proceed along second conveyor  12  until they begin to pass under dog  41 . At this point, second conveyor  12  begins to follow the rounded surface of second conveyor end pulley  51 . In this figure, second conveyor end pulley  51  is shown as a sprocket, used with the chain embodiment of second conveyor  12 . 
     Rather than follow the rounded edge of second conveyor end pulley  51 , the flanges contact upper wheel  42  and are propelled forward. Upper wheel  42  is driven by a belt or chain powered by upper wheel drive  57 . Soon after contacting upper wheel  42 , the upper leading edge of each flange is halted by dog  41 . The height of dog  41  above upper wheel  42  can be adjusted for flanges of different sizes using any appropriate means. In FIG. 6, the adjustment is made using rack  48  and gear  49 . Dog  41  is attached to rack  48  which in turn is fixed to reject conveyor  47 . The shape of dog  41  can also be changed to accommodate different types of flanges simply by rotating it 180 degrees about an axis perpendicular to the page. Once a flange makes contact with dog  41 , it begins to rotate counter-clockwise. Upper wheel  42  forces the flange back into its original orientation and moves the flange onto upper discharge conveyor  45 . 
     FIG. 7 shows the very similar mechanism of the second turn, lower section. As before, the flanges proceed along second conveyor  12  until they are arrested by stop pins  40 . When stop pins  40  are removed, the flanges proceed to the end of second conveyor  12 . There, the curvature of cam  44  provides a smooth transition off of second conveyor  12 . The flanges&#39; momentum carries them forward until the top edge of each flange contacts lower wheel  54 . As the top of each flange is propelled forward by lower wheel  54 , the bottom edge is caught on trip point  43 . Lower wheel  54  causes the flange to rotate clockwise, 180 degrees from its original orientation. Thus properly oriented, the flange moves away on lower discharge conveyor  46 . 
     Upper wheel  42  and lower wheel  54  are best made of urethane with a hardness of between durometer 20 and 90. The preferable hardness is between durometer 50 and 60. The wheels should rotate between 30 and 120 RPM with the best results being achieved near 60 RPM. 
     The second turn, lower section mechanism can be modified to accommodate many sizes of flanges just as the upper section. Lower wheel  54  is fixed to lower wheel mount  50  which is in turn rotationally affixed at wheel mount bearing  55 . Lower wheel  54  is powered by a belt or chain turned by lower drive wheel  56 . Lower wheel mount  50  is rotationally positioned by the action of hydraulic cylinder  53 , which itself is rotationally fixed to pillow block  52 . 
     It is desirable to mount hydraulic cylinder  53  such that it can rotate because the contact between hydraulic cylinder  53  and lower wheel mount  50  describes an arc during adjustment of lower wheel  54 , while hydraulic cylinder  53  is only capable of axial movement. Thus, lower wheel mount  50  rotates as hydraulic cylinder  53  extends and retracts. Hydraulic cylinder  53  is fixed to pin  58  to allow for relative rotation between hydraulic cylinder  53  and lower wheel mount  50  about an axis perpendicular to the page. As hydraulic cylinder  53  extends and retracts, it will itself rotate a small amount about pillow block  52 . 
     The height of lower wheel  54  above cam  44  is determined by the geometry of the mechanism and the extension of hydraulic cylinder  53 . Because the geometry is fixed, the system has only one degree of freedom. The particular geometry used in FIG. 7, particularly the length of lower wheel mount  50 , makes lower wheel  54  very sensitive to adjustments in the extension of hydraulic cylinder  53 . To allow for minute variations in positioning of lower wheel  54 , a linear transducer and monitor (not shown) can be used in conjunction with hydraulic cylinder  53 . 
     There are of course other alternate embodiments which are obvious from the foregoing descriptions of the invention, which are intended to be included within the scope of the invention, as defined by the following claims.