Abstract:
A punch plasterer is disclosed which in one action, drives and countersinks a fastener into wood or other materials and which fills the resulting cavity above the fastener thereafter. The present invention includes a punch tool for driving the fastener and first and second resilient springs for reciprocating the punch and for dispensing a predetermined amount of plaster. A plurality of plaster sizes may be used according to the size of the fasteners utilized.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to carpentry and construction tools, and more specifically, to a tool which in one action, countersinks a fastener and fills the countersink cavity to provide a smooth finish. 
     2. Description of Related Art 
     When a carpenter places a nail into a finished piece of wood such as a door or a piece of furniture, it is necessary to countersink the nail and to apply filler to the countersink cavity in order to provide a smooth finish. The filling or plastering process is typically accomplished in two steps. First the nail is countersunk into the material and second, plaster or other filler is manually applied to the cavity created by countersinking. This two step process wastes a considerable amount of time and is not uniform since there is no way of knowing precisely the exact amount of filler needed to fill each cavity. The carpenter inevitably uses too much or not enough plaster. Furthermore, manual plastering becomes very laborious and less precise after repeat applications. 
     Pneumatically driven nail machines are known which dispense a predetermined quantity of plaster into the cavity thereafter. However, these machines can be expensive, bulky, and not appropriate for all applications. Thus, it can be seen that a device that is relatively small and inexpensive is needed for countersinking nails and for plastering the resulting cavity. 
     SUMMARY OF THE INVENTION 
     To overcome the limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention in accordance with the principles set forth herein, discloses a manually operated punch plasterer. The present invention enables a carpenter to simultaneously embed and countersink a nail and to fill the resulting countersink cavity with the exact amount of filler needed. 
     A first bias means concentric to the driving axis of the punch is compressed upon striking of an anvil and provides a recuperating force to return the punch to its original position. A second bias means also disposed concentric to the driving axis of the punch, is compressed upon striking the anvil and is not released until the first bias means has substantially returned to its equilibrium state. The second bias means imparts a secondary force to the punch for driving it downwardly to discharge a predetermined portion of filler into the countersink activity. 
     Thus, in one action of striking the punch anvil, the fastener is countersunk into the material and a predetermined amount of filler is discharged and troweled into the countersink cavity. 
     These and various other advantages and features of novelty which characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages, and the objects attained by its use, reference should be made to the drawings which form a further part hereof, and to the accompanying descriptive matter, in which there is illustrated and described specific examples of the devices and methods in accordance with the principles of the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring now to the drawings, which like reference numbers represent corresponding parts throughout: 
     FIG. 1 is a perspective view of a punch plaster in accordance with the principals of the present invention; 
     FIG. 2 is a cross sectional side view of the punch plasterer in an inoperative position; 
     FIG. 3 is an exploded view of the punch plasterer in accordance with the principles of the present invention; 
     FIG. 4 is a cut away view of the punch plasterer in accordance with the principles of the present invention; 
     FIG. 5 is a view of the punch plasterer in a first operative position; 
     FIG. 6 is a view of the punch plasterer in a second intermediate operative position; 
     FIG. 7 is a view of the punch plasterer in a third operative position; 
     FIG. 8 is a view of the punch plasterer taking away surplus wax; and 
     FIG. 9 is a view of how the punch plasterer is cleaned. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     U.S. Pat. No. 5,092,508, entitled &#34;COMPRESSED AIR NAIL MACHINE&#34;, issued Mar. 3, 1992, to Vigil Rio, the inventor of the present invention, and which is herein incorporated by reference, discloses a pneumatically operated nail machine incorporating a device which utilizes exhaust for filling the cavity above each nail head after it is placed into the wood. 
     In the following description of the preferred embodiment, a manually operated punch plasterer which utilizes first and second bias means is disclosed. Reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration a specific embodiment in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. 
     Throughout the specification, reference in which the device is to be practiced is made to a nail as the fastener and wax as the filler. Those skilled in the art will be able to bring to mind other suitable expedients for fasteners and plasters for which the principles of the present invention may be practiced. 
     Reference is now made to FIGS. 1 and 3 which depict a perspective view and an exploded view of the punch plasterer in accordance with the principles of the present invention. 
     An anvil 1 manufactured of a steel or a plastic material suitable to withstand substantial striking forces, is disposed at a proximal end of the device. A substantially cylindrical rod 2 is attached to the anvil 1 and extends from the proximal end towards a distal end. The rod 2 is manufactured of a high-quality steel suitable for withstanding sizable striking forces. 
     Forming the body of the present invention, is a cylinder 4 substantially concentric with the rod 2. The cylinder 4 is threaded in both its proximal and distal end and maybe made of a rough cast steel. The cylinder 4 comprises a first chamber in its proximal end having interior walls defining an aperture concentric with the rod 2 but of a slightly larger diameter. The cylinder 4 further comprises a second chamber in its distal end having interior walls of a diameter larger than the first chamber and including two notched grooves 24 for operative engagement with a pair of hook members 10, described in more detail herein below. 
     Forming the exterior portion of the body is a knurled elastomer or rubber grip 3 disposed on the outer surface of the cylinder 4 for providing an easy grip surface. 
     An end cap 5 having a substantially annular concentric aperture is threaded into the cylinder 4 at the proximal end. The rod 2 passes through the aperture in the end cap 5 and is rigidly attached at the proximal side to the anvil 1 and the distal end of the rod 2 extends through the first and second chambers of cylinder 4. A ferrule 23 is annularly disposed around rod 2 at a distance approximately one-half to two-thirds from its proximal to its distal end. Rod 2 has a groove 25 machined around its circumference at a distance approximately one-third to one-half from its proximal end to its distal end for receiving a retaining ring 7. 
     A first bias means 6, such as, but not limited to, a spring, of predetermined stiffness having a diameter slightly larger than the aperture defined by the first chamber in cylinder 4, is disposed coaxial and coextensive with the rod 2 between the retaining ring 7 and the inner wall of the first chamber. Retaining ring 7 inhibits the first bias means 6 and the rod 2 from traveling through the aperture in end cap 5. Forces applied to the anvil 1 compress first bias means 6. The compression of first bias means 6 stores recuperating energy to return rod 2 to its original position. 
     A second bias means 8, such as, but not limited to, a spring, having a stiffness greater than the first bias means 6 is disposed coaxial and coextensive along the distal end of rod 2 between the ferrule 23 and a punch tool 9. The punch tool 9 is made of a similar high-quality steel as the rod 2 and has a substantially cylindrical body with an orifice at its proximal end for operative engagement with rod 2. The thrust of the rod 2 imparts a force on the punch tool 9 as the rod 2 is stroked in a direction towards the distal end. At its distal end, the punch tool 9 has a substantially cylindrical member of lesser diameter than its body for imparting the applied force onto the head of the fastener 21. A pair of flexible hook members 10 are attached to the side walls of the body of the punch tool 9 and extend substantially parallel to the rod 2 towards the proximal end. The flexible hook members 10 operably engage the ferrule 23 on the rod 2 during a down stroke of the rod 2 in response to a force being imparted on the anvil 1. On an up stroke of the rod 2, the hook members 10 are disengaged from the ferrule 23 as they contact the notched grooves 24 in the interior walls of the second chamber in cylinder 4. 
     As best seen in FIGS. 2 and 3, a body 12 made of steel or plastic, has mating threads 26 for coupling to the distal end of cylinder 4. The body 12 includes a contoured mouth 27 defining an aperture having an axis which is substantially concentric with the axis of the rod 2. The punch tool 9 has a mating guide 11 disposed within the mouth 27. The internal diameter of the guide 11 is substantially equal to the external diameter of the punch tool 9. The exterior of the guide 11 has salient features to prevent movement within the mouth 27. The guide 11 has an orifice in its side wall in operative alignment with the portion of the body 12 which stores the wax 14. 
     The punch tool 9 and guide 11 are interchangeable as a pair for different applications. The mating thread 26 of the body 12 is unscrewed to remove the body 12 from the cylinder 4, thereby releasing the punch tool 9 and guide 11 from the cylinder 4. A replacement punch tool 9 and guide 11, having more or less width, may be used in place of the first punch tool 9 and guide 11. 
     The body 12 extends substantially perpendicular to the axis of the rod 2. The body 12 defines a hollow cylinder for housing a filler bar such as wax, and an assembly that provides means for advancing the filler into the contoured mouth 27. The means for advancing the filler comprises a plastic thrust piece 15 for engagement with a filler bar 14, a thrust bias means 16 coupled to the thrust piece 15 for providing compressive forces for advancing the filler into the contoured mouth 27, and a coupling 17 for securing the assembly to the proximal end of the body 12. The coupling 17 may include a bayonet member for securing the assembly to the body 12 and for providing easy release. Those skilled in the art will be able to bring to mind other suitable expedients for a quick release coupling for which the principles of the present invention may be practiced. The body 12 may include an additional area for providing storage for a helical shaped cleaner 18. The cleaner 18 is preferably made of metal or plastic. In the preferred embodiment, the storage area is a hollow cylindrical region in the body 12 parallel and beneath the means for advancing the filler. The cleaner 18 is removable disposed in the cylindrical region and maybe used to clean filler from the body 12. 
     Referring now to FIG. 9, the cleaner 18 is depicted for cleaning filler from the body 12. The body 12 is removed from the cylinder 4 to avoid contact between the cleaner 18 and the punch tool 9. Although this feature is optional, it is useful for removing filler from the body 12 in the event that the body 12 was exposed to excessive heat such as being left in the sun. 
     A third bias means 13 having a body which flares from its proximal end to its distal end is operatively disposed between the punch tool 9 and the body 12 for providing dampening. The third bias means 13 has little stiffness and has an approximately displacement of two millimeters. To protect the surface of the material in which the fastener 21 is being driven, the third bias means 13 provides dampening so the forces applied to the anvil 1 are substantially transmitted through the punch tool 9 to the fastener 21 and not through the rest of the device. All of the applied energy to the anvil 1 passes to the fastener 21 not to the wood. 
     Reference is now made to FIGS. 4, 5, 6, and 7 which depict the present invention in four stages of operation. 
     In FIG. 4, the plaster punch is placed over the fastener 21 after it is driven into the wood. First bias means 6 and second bias means 8 are in an equilibrium state. 
     In FIG. 5, a hammer 19 applies a force to anvil 1 which is transmitted through the rod 2, to the punch tool 9, and to the fastener 21. Displacement of the rod 2 forces the external retaining ring 7 to compress the first bias means 6 between the retaining ring 7 and the wall defining the aperture between the first and second chambers in cylinder 4. The displacement of rod 2 also compresses the second bias means 8 between the ferrule 23 and the punch tool 9. As best seen in FIG. 5, the completion of the downstroke of rod 2 engages hook members 10 onto ferrule 23. 
     As best seen in FIG. 6, first bias means 6 recuperates rod 2 to its original position pulling up the punch tool 9. The recuperation of the punch tool 9 draws a predetermined amount of filler 14 into the guide 11 disposed in mouth 27. The recuperation of the punch tool 9 also brings hook members 10 into operative engagement with notched grooves 24 in the interior walls of the second chamber of cylinder 4. 
     As best seen in FIG. 7, the engagement with notched grooves 24 causes hook members 10 to flex and disengage from the ferrule 23. Disengagement of the hook members releases the second bias means 8 to drive the punch tool 9 downwardly. The punch tool forces the predetermined amount of filler 14 in guide 11 into the cavity 22 above the fastener 21. The second bias means 8 has a sufficient stiffness to compress the filler 14 into the cavity 22 providing a smooth finish on the wood. 
     Referring now to FIG. 8, the mouth 27 of the body 12 may include a beveled edge 20 for removing excess filler in the event that the fastener 21 was driven into an uneven surface such as a molding. The punch plaster is slightly inclined and scraped in a forward direction much like a carpenter&#39;s plane or pallet knife would be used. Excess filler will remain fastened on the beveled edge 20. 
     The foregoing description of the preferred embodiment of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Any modifications or variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims amended hereto.