Patent Application
20090308906
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1. Field of the Invention
The present invention relates, in general, to powered staplers and fastener applicators, and in particular, to powered staplers and fastener applicators for inserting fasteners into fastener caps intended to be used as a washers for holding roofing paper, insulation wrap, and coverings to houses, lumber, and other articles in the construction industry.
2. Information Disclosure Statement
Well-known plastic fastener cap washers are often used to hold down roofing paper, insulation wrap, and coverings on houses, buildings, lumber, and other structures in the construction industry. Such well-known fastener caps, as might be used with the present invention, are disclosed, for example, in Lamb, U.S. Pat. No. 6,302,310 (issued Oct. 16, 2001), fully included herein by reference, and Lamb, U.S. Pat. No. 7,090,455 (issued Aug. 15, 2006), fully included herein by reference. Often, powered nail guns and staplers are used to drive staples and the like through the fastener caps, and such powered nail guns and staplers often have so-called well-known “magazine towers” for holding a stack of the fastener caps, as may be seen, for example, in the previously-mentioned reference Lamb, U.S. Pat. No. 7,090,455 (issued Aug. 15, 2006), which also discloses that the stack of fastener caps may be melted together around portions of their circumferences so as to form a unitary stack of caps that can be loaded and unloaded from the cap magazine tower. It is also known to have reciprocating slider plates to feed the bottommost cap from the stack of caps in a cap magazine tower, pushing the bottommost cap into position under the nail or stapler gun's nose so that a staple or nail may be driven through the cap and into a workpiece.
A problem with prior art cap feeders is that the reciprocating slider plates have a relatively long stroke so that the bottommost cap can be moved from the cap magazine tower to the nailing/stapling position under the nose of the gun. If the position of the staple gun is moved while the reciprocating slider plate is moving the bottommost cap into position for nailing or while a staple is being driven through the cap into the workpiece, the staple gun's driver blade will come off of the top of the driven staple (because the staple and cap will not move with the gun but will be anchored by the partially-driven staple into the workpiece), causing the staple not to be fully driven into the workpiece. It is therefore desirable to provide a reciprocating cap feeder plate that has a shorter reciprocation distance than heretofore known in the prior art, such that the cap is moved more quickly into position during the stapling operation than heretofore possible, thereby allowing less time for the gun to be moved during stapling.
It is also desirable that the operator of the nail or staple gun have unimpeded view of the workpiece, and prior art cap feeding mechanisms and towers have traditionally blocked the view of the workpiece by the operator, and the linkages that coordinate the operation of the cap feeder and its reciprocating slider plate are often complex. It is therefore desirable to have a cap feeder for feeding caps from a stacked assembly of caps in a magazine tower, whereby the cap feeder is compact, operates quickly and reliably with the magazine tower placed closely adjacent to the nose of the gun, and has a simpler design than heretofore known in the prior art.
The present invention is an improved cap feeder for a fastener gun. The cap feeder includes a reciprocating cap pusher having a cap-engaging portion that feeds a cap from a stacked assembly of caps into a fastening position beneath a nose of the gun, and a grip finger, mounted to the cap pusher and extending beyond the cap-engaging portion, grips and holds the underside of the cap being fed.
It is an object of the present invention to provide an improved cap feeder for feeding a cap from a stacked assembly of caps, in which the cap feeder is compact, operates quickly and reliably, and permits a cap magazine tower holding the stacked assembly of caps to be placed closely adjacent to the nose of the gun so that the cap being fed moves a shorter distance from the magazine to the nose of the gun than in the prior art. It is a further object of the present invention to permit the cap being fed from the cap magazine tower to be closer to the workpiece, while a fastener is being driven through the cap and into the workpiece, than permitted by prior art cap feeders.
Referring to the drawing figures, the present invention is an improved cap feeder for a fastener gun 22. Except for modifications to the fastener gun 22 as hereinafter described to accommodate the improved cap feeder 20, fastener gun 22 is well-known to those skilled in the art. Fastener gun 22 has a well-known fastener magazine 24 holding a supply of well-known fasteners such as staples 26. Fastener gun 22 is used in a manner well-known in the prior art to insert fasteners, such as staples 26, through well-known plastic fastener caps 28 and into a workpiece 30, as best seen in
Fastener gun 22 includes a well-known upright cap magazine tower 34 for holding a stacked assembly 36 of caps 28, and caps 28 may preferably be melted together at circumferential portions as disclosed in Lamb, U.S. Pat. No. 7,090,455 (issued Aug. 15, 2006), fully included herein by reference. Fastener gun 22 includes a nose 38 and a pneumatic-powered driver 39 for driving a fastener 26 from the nose, through a cap 28 when the cap is in a fastening position beneath the nose 38, and into workpiece 30.
Fastener gun 22 also includes a footplate 40 that rests against the workpiece 30. While prior art fastener guns 22 are known to have footplates that rest against a workpiece, the footplate 40 of the present invention is modified from the prior art and is adapted for use with the cap pusher and grip finger of the present invention, as hereinafter described in detail.
The improved cap feeder 20 of the present invention is for sequentially feeding the bottommost cap from the stacked assembly of caps into a fastening position 42 as shown in
Cap feeder 20 of the present invention includes a cap pusher 44 mounted for reciprocation with respect to footplate 40, moving from a first position 46 shown in
In an improvement over the prior art, the cap magazine tower 34 is mounted proximate the nose 38 so that the movement of caps 28 from the stacked assembly of caps 36 to fastening position 42 is a very short distance. The close mounting of the cap magazine tower to the nose 38 is possible because of the structure of the improved cap feeder 20 of the present invention, as will now be explained in detail.
Cap feeder 20 includes a reciprocator 54, preferably a well-known pneumatic first reciprocating piston 56 mounted within a cylinder 58 (see
The improved cap feeder 20, in a significant improvement over the prior art, includes a grip finger 72 mounted to cap pusher 44 as by welding or preferably by a rivet 74 into cap pusher 44, with grip finger 72 extending from the leading portion of cap pusher 44 beyond the cap-engaging portion 50 of cap pusher 44 so that, when the cap-engaging portion is engaging the bottommost cap 28 of the stacked assembly 36 of caps, the grip finger extends under the bottom edge of the cap 28 and engages the underside 76 of cap 28 as best seen in
Cap pusher 52 is coupled to first reciprocating piston 70 of reciprocator 54 by a linkage 78, preferably rigid and a unitary piece of metal, that is preferably fixedly joined to cap pusher 52 as by welding or a rivet 82 and fixedly joined to piston rod 70 as by a nut 84 threaded onto the distal end of piston rod 70. Cap pusher 44 is preferably mounted to footplate 40, for reciprocation with respect to footplate 40, by a pair of longitudinally-entrapping lips 85 (best seen in
In the preferred embodiment of the present invention, the well-known pneumatic-powered driver 39 of the fastener gun 22 includes a second reciprocating piston 86 mounted for reciprocation within a cylinder 88 of driver 39 and sealed to cylinder 88 by a well-known O-ring 90. It is well-known to have trigger valve 68 supply air above piston 86 to cause the driver 39 to impact a leading fastener 26 from the supply of fasteners in the fastener magazine and to cause the fastener to be driven through the cap 28 and the workpiece as heretofore described. As trigger valve 68 is actuated by the operator, the air is bled from below second piston 86 and is applied above second piston 86 so as to cause the driver to impact the fastener 26. In the improvement of the present invention, port 64 of reciprocator 54 is pneumatically coupled by an air line 92 to a port 94 that is in communication with the chamber above second piston 86, such that, when pressurized air is supplied to second piston 86 by trigger valve 68, pressurized air is simultaneously applied to port 64 of reciprocator 54 at the same time that trigger valve 68 bleeds air from port 66 of reciprocator 54, causing first piston 56 to move the cap pusher 44 from its first position to its second position in tandem with the movement of the driver piston 86 toward the fastener 26. While piston 56 and/or piston 86 could be spring biased back into their original positions when the trigger valve 68 is released by the operator, in the preferred embodiment the trigger valve, when released, will bleed air from the chamber above piston 86 while also supplying pressurized air to port 66, causing reciprocator piston 56 to quickly retract to its original position (bringing cap pusher 44 back to the first position) and allowing piston 86 to retractingly rise.
Preferably, for safety and protection of the operator, a well-known safety interlock linkage 96, coupled to trigger valve 68, extends below the footplate 40 for engagement with the workpiece (as best seen in
Although the present invention has been described and illustrated with respect to a preferred embodiment and a preferred use therefor, it is not to be so limited since modifications and changes can be made therein which are within the full intended scope of the invention.
