Patent Publication Number: US-6212762-B1

Title: Lumber tagger

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to staple driving apparatus with means to convey work relative to a driving station. 
     BACKGROUND OF THE INVENTION 
     It is common to place tags on dimension lumber for price and inventory control purposes. Affixing these tags to individual pieces of lumber has, unfortunately, been a time-consuming process. Although a staple gun is normally used, tagging proceeds slowly since manually positioning a staple gun and squeezing its trigger to affix a tag is a relatively slow endeavor. Thus, a manufacturer of large quantities of lumber can find itself employing, at high cost, several laborers for tagging purposes. 
     Efforts to automate the process of tagging lumber have not met with great success. Normal variations in the length, width, and height of dimension lumber from one piece to another have plagued past designers by making it difficult to affix tags in rapid succession. Warps or twists in many lumber pieces further complicate the matter of affixing tags. A need, therefore, exists for an automated apparatus which is capable of rapidly affixing tags to an indefinite number of lumber pieces regardless of slight variations in the length, width, height and shape of the lumber pieces. 
     SUMMARY OF THE INVENTION 
     In light of the problems associated with the known apparatus for affixing tags to dimension lumber, it is a principal object of the invention to provide a lumber tagger which, with little or no human intervention, will staple tags in rapid succession onto the ends of a plurality of lumber pieces which may vary somewhat from one to the other in terms of: length, width, height and the presence of warps. 
     It is another object of the invention to provide a lumber tagger of the type described which makes minimal physical contact with lumber being tagged in order to reduce wear upon its parts and to maximize its useful life. 
     It is an object of the invention to provide improved elements and arrangements thereof in a lumber tagger for the purposes described which is lightweight in construction, relatively inexpensive to manufacture, and fully dependable in use. 
     Briefly, the tagger in accordance with this invention achieves the intended objects by featuring a motor-driven chain for positioning adjacent a lumber conveyor. A stapler is positioned adjacent the chain for driving a staple through a tag and into a piece of lumber on the conveyor. A tag feeding attachment urges one tag of a contiguous sequence of tags into alignment with the stapler and severs the tag. The stapler and tag feeding attachment are actuated in sequence by a central processing unit in response to signals from a photosensor positioned near the stapler. 
     The foregoing and other objects, features and advantages of the present invention will become readily apparent upon further review of the following detailed description of the preferred embodiment as illustrated in the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention may be more readily described with reference to the accompanying drawings, in which: 
     FIG. 1 is a side view of a lumber tagger in accordance with the present invention. 
     FIG. 2 is top view of the lumber tagger of FIG. 1 shown positioned against a lumber conveyor for use. 
     FIG. 3 is a schematic diagram showing the control system for the lumber tagger. 
    
    
     Similar reference characters denote corresponding features consistently throughout the accompanying drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the FIGS., a lumber tagger in accordance with the present invention is shown at  10 . Tagger  10  includes a frame  12  adapted for mounting upon supports  14  for a horizontal conveyor  16 . Frame  12  carries a feeder  18  which adjusts the positions of pieces of lumber  20  on conveyor  16  so that they pass an adjacent stapler  22  at a predetermined distance. As lumber pieces  20  move past stapler  22  on conveyor  16 , a fixed field photosensor  24  detects their presence and sends an electrical signal to a remote, central processing unit (CPU)  26  which, in turn, energizes stapler  22  so as to affix a tag (not shown) to a lumber piece  20  with a staple (not shown). 
     Frame  12  is constructed principally of heavy gauge metal sheeting and includes a top wall  28 , a bottom wall  30 , front wall  32 , and a back wall  34  connecting the top and bottom walls together. A motor mounting plate  36  extends upwardly from top wall  28 . Brackets  38  extend rearwardly from bottom wall  30  for mounting frame  12  on conveyor supports  14 . 
     Connected to one end of bottom wall  30  by a hinge  40  is a stapler support platform  42 . Platform  42  has a front side from which a guard plate  44  extends upwardly to prevent the inadvertent contact of lumber pieces  20  with stapler  22 . On the side of platform  42  opposite hinge  40 , a column  46 , carrying a roller  48  at its upper end, is secured. The roller  48  is adapted to engage a lumber piece  20  having warps thereby elevating the platform  42  and permitting stapler  22  to staple a tag into the center of the warped piece. 
     To prevent stapler  22  from jumping upward when roller  48  contacts a lumber piece  20 , a counterweight  50  is attached to the bottom of platform  42  by means of an elongated rod  52 . As shown, rod  52  is slanted to project counterweight  50  toward bottom wall  30 . Not only does such a positioning keep counterweight  50  beneath bottom wall  30  or platform  42  during normal use of tagger  10  but such also helps maintain even an pressure on a warped lumber piece  20  through roller  48  regardless of the inclination of platform  42  and rod  52 . 
     Feeder  18  includes a pair of spaced-apart, sprocket wheels  54  and  56  supporting an endless chain  58  in a position to engage the ends of lumber pieces  20  on conveyor  16  at a slight angle when viewed from above. Wheel  56  is connected to a variable speed motor  60  via drive unit  62  such that chain  58  can be moved at the same speed as conveyor  16 . During use, lumber pieces  20 , having variable initial positions on conveyor  16 , are pushed by chain  58  laterally across conveyor  16  so that they will pass by stapler  22  at a set distance. 
     Stapler  22  is substantially like the one shown in U.S. Pat. No. 5,014,896, issued May 14, 1991, to Reitmeier et al and incorporated for all purposes herein. The construction of stapler  22  will not be belabored, however, such includes a pneumatic staple gun  64  secured to platform  42  which, upon actuation, drives staples (not shown) from a head  66  located adjacent guard plate  44  toward lumber pieces  20 . A pneumatic tag feeding attachment  68  is joined to staple gun  64  and has a roll support  70  rearward of head  66 . Tags, connected together so as to form a roll  72 , are delivered from support  70  to a cutter  74  located next to head  66  by feeding attachment  68 . 
     The tagging sequence is not actuated by the manual squeeze of a trigger as is shown by Reitmeier et al but, rather, is automatically controlled by CPU  26 . Thus, at a set time after receiving a signal from photosensor  24 , secured by arm  25  to top wall  28 , CPU  26  delivers a signal to a solenoid-actuated air valve  76  operatively coupled with tag feeding attachment  68 . Upon receiving the latter signal, valve  76  is opened to deliver compressed air from tank  75  to tag feeding attachment  68  which is thereby energized to advance a part of roll  72  past cutter  74  which, then, slices a single label from roll  72 . 
     Almost simultaneously with the single label being sliced, CPU  26  sends a signal to a solenoid-actuated air valve  78  operatively coupled with stapler  22 . Upon receiving the signal, valve  78  is opened to actuate staple gun  64  with air from tank  75  and drive a staple outwardly from head  66  through the label severed from roll  72  and into an adjacent lumber piece  20 . After a short interval, both solenoid-actuated air valves  76  and  78  are closed by CPU  26 . 
     From the foregoing, it should be appreciated that the use of tagger  10  is straightforward. First, a plurality of lumber pieces  20  are unloaded onto moving conveyor  16 . As lumber pieces  20  engage chain  58  (whose speed is adjusted to correspond with that of conveyor  16  by varying electrical current flow to motor  60  through variable resistor  85 ), such are pushed laterally to a fixed distance from stapler  22 . Next, photosensor  24  detects the leading edge of a lumber piece  20  and sends a signal to CPU  26  to initiate the tagging sequence. 
     Tagging proceeds automatically without any human intervention. First, tag feeding attachment  68  is actuated via the opening of valve  76  to cut a single tag from its outer end. After several milliseconds have elapsed, staple gun  64  is energized by opening valve  78  to drive a staple through the tag and into a lumber piece  20 . If the lumber piece  20  had an appreciable warp, the stapler  22  would have been elevated by means of roller  48  thereby ensuring that the staple and tag would be attached to the warped lumber piece at a set distance from its top edge. After another short interval, feeding attachment  68  and staple gun  64  are deenergized by closing valves  76  and  78 . Deenergization of tag feeding attachment  68  causes such to advance tag roll  72  toward cutter  74  in anticipation of the severance of another tag from roll  72 . 
     Tagger  10  includes an electrical lead  80  with a plug  82  at its free end for connection to a source of electrical power. A switch  84  in lead  80  permits tagger  10  to be readily turned on and off. A “kill” switch  86 , also on lead  80 , may be mounted in a prominent location for deenergizing tagger  10  in the event of an emergency. 
     While the invention has been described with a high degree of particularity, it will be appreciated by those skilled in the art that modifications may be made thereto. For example, a belt may be substituted for chain  58  with slight modifications to wheels  54  and  56 . Therefore, it is to be understood that the invention is not limited to the sole embodiment described above, but encompasses any and all embodiments within the scope of the following claims.