Laid flooring end jointer
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a jointer for jointing the ends of laid flooring boards, particularly for use in repairing floors. 
     2. Prior Art 
     In the past, in order to replace defective boards in repairing laid floors, the end of a laid flooring board has been jointed by the use of a hand-held chisel, in some cases supplemented by cutting with a hand-held rotary power saw. Not only has such procedure been time-consuming, but there is danger of inadvertently cutting into a board adjacent to the board being jointed which is not to be replaced. 
     SUMMARY OF THE INVENTION 
     A principal object of the present invention is to use a router for jointing the end of a laid flooring board. 
     Another object is to guide such a router so as to locate the jointing operation accurately and provide a straight cut which is square relative to the length of the board. 
     A further object is to control the displacement of the router so as to ensure that a jointing cut of precise length is made on the end of a selected floor board laid between adjacent flooring boards. 
     An additional object is to support a router for sliding displacement in controlled fashion by mechanism that can be set up quickly, easily and accurately. 
     It is also an object to provide mechanism for holding a router mounting firmly in a desired relationship to laid flooring during the operation of jointing the end of a laid flooring board. 
     The foregoing objects can be accomplished by mounting a router on a supporting slide that is reciprocable in guideways with stops for limiting movement of the slide along the ways to enable the jointing cut to be of precise length. The ways are held immobile by the worker kneeling on a positioning plate attached to the ways and having a gripping undersurface engageable with the floor to prevent sliding of the positioning plate over the floor. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top perspective of the jointer. 
     FIG. 2 is a top plan of the jointer. 
     FIG. 3 is a vertical section through a portion of the jointer taken on line 3--3 of FIG. 1. 
     FIGS. 4, 5 and 6 are corresponding vertical sections through a portion of the jointer showing parts in different positions and having parts broken away. 
     FIGS. 7, 8 and 9 are fragmentary plans of a portion of the router showing parts in different operating positions and having parts broken away. 
    
    
     DETAILED DESCRIPTION 
     In repairing laid floors 1 made of individual boards 2, it may be necessary to replace defective parts of laid boards. In order to make a tight end joint 3 between a laid board to remain in place and a new board, it is necessary that the laid board be jointed to provide a new square end. Because the boards are laid on a subfloor, it is very difficult to joint with a saw the end of a board laid between two adjacent boards. Using a hand chisel to cut out a section of a laid flooring board and to joint a new end is time-consuming, and it is difficult to make a smoothly jointed board end. The present invention uses a router 4 to joint the end of a laid flooring board 2. 
     A difficulty with using a router held and guided by hand to remove a portion of a laid flooring board and to joint a new end on the laid board is the care with which the router must be manipulated in order to make a smooth square cut, even if a guideline is marked on the board to be cut, without injury to adjacent laid boards. The jointer of the present invention enables such jointing to be accomplished by the router 4 easily, quickly and accurately. 
     A conventional plunge router 4 is supported for elevational movement by posts on a circular base plate 5 having a central circular aperture 6 through which the router bit 7 projects downward. The router can be moved downward from the position shown in FIG. 5 a distance such that the lower end of the router bit just cuts through the thickness of the flooring boards 2 as shown in FIGS. 5 and 6. 
     The base plate 5 of the router is mounted on and attached to a slide 8 received within a rectangular aperture 9 of a router-guiding frame 10 as shown in FIGS. 1 and 2 constituting a jig. Tongues 11 forming linear ways extend in parallel relationship along the opposite longitudinal sides of the aperture 9. Opposite edges of the slide 8 are rabbeted at their undersides to provide upper flanges bearing of the upper sides of the tongues 11 so that the router and base plate can be lifted out of the ways in any position along the ways. 
     Reciprocation of the slide 8 along the ways 11 within the aperture 9 can be limited by a compound stop bar composed of an upper bar 12 and a lower bar 13 spanning across the aperture 9 between the ways. The opposite end portions of the upper bar 12 rest on the upper sides of the tongues 11. The opposite ends of the lower bar 13 have rabbets 14 to enable the upper portion of the bar length to clear the tongues 11 and to provide a bottom flange 15 extending under the tongues 11 as shown in FIG. 3. 
     Near opposite ends of the bars 12 and 13, respectively, bolts 16 are threadedly secured in the lower bar 13, and the upper bar 12 has correspondingly located apertures to slide over the upper ends of the bolts. Clamping knobs 17 have internally threaded cores that can screw onto the projecting upper ends of the bolts 16 so that, when such knobs are tightened, their skirts will press against the upper side of the upper bar 12. The depths of the rabbets 14 are slightly less than the thicknesses of the tongues 11 in the aperture 9 so that pressure exerted on the upper bar 12 by the skirts of the knobs 17 will pinch the tongues 11 between the marginal portions of the upper bar 12 and the lower flanges 15 of the lower bar 13 to fix the stop in any selected position along the ways formed by the tongues 11 for adjusting the length of the stroke of slide 8. 
     Auxiliary stops 19 are mounted in recesses 18, respectively, on the margin of the frame aperture 9 at the side of the router opposite the stop bar 12, 13 and on the margin of such stop bar adjacent to the router. Each of such auxiliary stops is a circular plate mounted on a pivot having an unthreaded portion extending through the stop disk, a threaded mounting shank 20 screwed into the frame 10 or stop bar 13 beneath the recess 18 and a head 21 disposed eccentrically of the stop disk center. Two pins 22 project upward from the circular plate to provide handles for angularly adjusting the plate on its pivot 20. Such stops can be held either in a projected position or in a retracted position by a detent mounted in the bottom of the recess 18 as shown in FIG. 3. Buttons are provided on the opposite edges of the slide 8 in positions for engagement with the stops 19 to facilitate precision location of the slide relative to the frame aperture 9. 
     A positioning plate 23, preferably made of transparent plastic material such as polycarbonate, is secured to a top flange 24 projecting from one edge of the router-guiding frame 10 by bolts 25. While such flange is shown as extending parallel to the ways 11 and to the path of reciprocation of the slide 8, such flange could be located at one end of the router-guiding frame 10 and extend perpendicular to the ways and path of reciprocation of the slide 8 if desired. 
     The bottom of the positioning kneeling plate 23 is substantially coplanar or flush with the bottom of the frame 10. At least a portion of the lower surface of the positioning plate is of gripping material which may be of abrasive character such as coarse emery paper, otherwise known as safety tread tape, or friction material such as elastomer, to prevent inadvertent shifting of the jointer when pressure is applied to the positioning plate by the worker kneeling on it. Conveniently, the gripping surface is in the form of several thin strips 26 of coarse emery paper bonded to the bottom of the positioning kneeling plate, as indicated in FIG. 1. 
     Also, the positioning kneeling plate 23 has a reference line 27 on its undersurface which can be aligned with a longitudinal joint between flooring boards 2 to locate the guideways 11 perpendicular to the longitudinal joints between the flooring boards. Also, the frame 10 has a guide line 27&#39; at the side of its aperture 9 opposite the kneeling plate which is aligned with the reference line 27 to enable the frame to be placed in proper position with reference to a joint between the flooring boards at opposite sides of the frame 10. 
     In use, the reference line 27 is placed in registration with the longitudinal joint along one edge of a laid flooring board a portion of which is to be removed and on which a new jointed end is to be formed. The positioning plate reference line 27 and frame reference line 27&#39; are located lengthwise of the laid flooring boards to locate the router bit 7 in position to make the end cut of the laid flooring board at the proper position. The clamping knobs 17 can then be loosened and the stop 12, 13 can be positioned so that, when the auxiliary stops 18 are in the positions shown in FIG. 7, both stops being projected into the aperture 9, the space between such auxiliary stops will be equal to the width of the slide 8 parallel to the ways 11 plus the width of a flooring board less the diameter of the router bit. 
     With the jointer held in this position by the worker kneeling on the positioning kneeling plate 23 alongside the router, the router can be moved downward from the position shown in FIG. 4 to the position shown in FIG. 5. With the router held in this position, the slide 8 can be reciprocated across the board to form the jointed board end 3, as shown in FIG. 6. The router will then be raised back to the position of FIG. 4, and the jointer can be removed from the location of the cut. It will then be necessary to touch up the jointed flooring board end by chiseling out the fillets formed by the router at each end of the cut. 
     If the portions of the boards at opposite sides of the board to be jointed are to be replaced, the auxiliary stops 19 are adjusted angularly about their pivots 20 a half turn, i.e., 180 degrees, from the positions shown in FIG. 7 to the reverse positions shown in FIG. 8. The degree of eccentricity of the auxiliary stops is such that the stroke of the slide 8 can be increased by thus turning both auxiliary stops a distance equal to the diameter of the router bit 7 plus a small amount such as one-quarter of an inch. Thus, if the diameter of the router bit is one-half inch, a half turn repositioning of one auxiliary stop would increase the possible travel of the slide 8 by three-eighths of an inch and turning both stops would increase the travel three-quarters of an inch. Such movement will enable the jointing cut to be made entirely across the width of a laid flooring board as shown in FIG. 8. 
     If it were desired for a jointing cut to encroach into the board on only one side of the board the end of which is to be jointed, the auxiliary stop 19 on the frame would be positioned in the projected position as shown in FIG. 9 while the auxiliary stop on the stop bar 12, 13 would be in the retracted position so that the router bit 7 could make a clean jointing operation at the end nearer the stop bar, whereas it would be necessary to remove the fillet at the opposite end of the jointing cut with a chisel.