Abstract:
A laser-guided stair rail drill guide which may be mounted on a tentatively set stair rail to aid in the alignment for drilling of the bottom of the rail and marking the surface of the riser below, by use of a laser beam aligned with a longitudinal axis of a drill bit of a drill mounted in the guide. Using the guide of the invention allows for the holes in the bottom of the stair rail and the top of the riser below to be easily and precisely aligned, so that a baluster may be installed perfectly vertically therebetween.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a device and guide for drilling stair rails and treads in alignment to receive balusters. More particularly, the invention comprises a laser-guided drill press apparatus which may be mounted on a tentatively set stair rail to aid in the alignment for drilling of the bottom of the rail and marking the surface of the riser directly below, by use of a laser beam aligned with the drill bit, so that a baluster may be set perfectly vertically. 
   2. Description of the Prior Art 
   Devices for guiding drills for precision drilling, such as free standing drill presses are extremely well known in the art. Likewise, there are a number of devices for use with hand held tools, such as drills which may be adapted to specific drilling needs. 
   U.S. Pat. No. 6,692,200, issued to Francis Peterson on Feb. 17, 2004; U.S. Pat. No. 6,587,184, to Christoph Wursch, et al., on Jul. 1, 2003; and U.S. Pat. No. 6,328,505, to Howard Gibble on Dec. 11, 2001, each disclose guiding devices for hand held tools, such as drills, while U.S. Pat. No. 6,375,395, issued to Michael Heintzeman on Apr. 23, 2002 discloses a laser guidance device for a hand held power drill. 
   U.S. Patent Application Number US 2003/0108395, by Anthony Douglas, et al., published on Jun. 12, 2003 discloses a tool positioning system which facilitates the positioning of a drill at a specific site for drilling. 
   While each of the above cited issued and pending patents discloses a specific element of the present invention, none, taken either singly or in combination, is seen to describe the instant invention as claimed. 
   SUMMARY OF THE INVENTION 
   The present invention provides a system for positioning and drilling holes in the underside of a stair railing and, by use of a laser beam aligned with the drill bit, marking of the treads immediately below such that the holes may be precisely aligned to ensure that the balusters are vertical. With most existing systems and methods, the precise alignment of the holes for the balusters is a tedious job requiring tiring contortions by the craftsman. The present invention makes significant improvements to the process by providing a device which mounts on the railing that is to be mounted, suspending a drill from a self plumbing guide bar, and projecting a laser beam on to the upper surface of the tread below, in perfect alignment with the drill bit at the lower surface of the railing, to precisely pinpoint the points for drilling. 
   Accordingly, it is a principal object of the invention to provide a laser-guided stair rail drill guide which is economical to procure. 
   Another object of the invention is to provide a laser-guided stair rail drill guide which is relatively light weight. 
   It is another object of the invention to provide a laser-guided stair rail drill guide which is easy to mount for use. 
   It is a further object of the invention to provide a laser-guided stair rail drill guide which is easy to align for vertical drilling. 
   Still another object of the invention is to provide a laser-guided stair rail drill guide which is self plumbing. 
   It is again an object of the invention to provide a laser-guided stair rail drill guide which precisely pinpoints the locations for drilling. 
   It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes. 
   These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Various other objects, features, and attendant advantages of the present invention will become more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein: 
       FIG. 1  is front view of a preferred embodiment of the rail guide of the laser-guided rail drill guide of the present invention. 
       FIG. 2  is an environmental perspective view of the template of the present invention. 
       FIG. 3  is a side view of the laser-guided rail drill guide of the preferred embodiment of the present invention, the rail guide  20  being cut away at line  3 - 3  of  FIG. 1 . 
       FIG. 4  is an environmental perspective view of the preferred embodiment of the present invention having a rotating drill mount assembly in its in-use position, the rail guide  20  being cut away at line  3 - 3  of  FIG. 1 . 
       FIG. 5  is an environmental perspective view of the preferred embodiment of the present invention with the drill mount assembly in drill installation/removal position, the rail guide  20  being cut away at line  3 - 3  of  FIG. 1 . 
       FIG. 6  is a view of a drill switch incorporated into the drill advancement handle mechanism. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The laser-guided rail drill guide  1 , at  FIGS. 1 through 6 , of the present invention consists of five basic elements, a rail guide  20 , a suspension bar  70 , a drill mount assembly  80 / 80   a , a drill  100  and a laser mount  110 . 
   The rail guide  20 , at  FIGS. 1 and 3  through  5 , has a clamp riser  22  which consists of a substantially vertical plate having a height with an upper end  22   u  and lower  22   l  end. The clamp riser  22  is preferably rectilinear in shape. A rail bracket housing  24 , having a length, a width and a height, is movably affixed to and extends from the clamp riser  22 , substantially normal thereto and from a point proximate upper end  22   u  of clamp riser  22 . The substantially rectilinear shape of the clamp riser  22  prevents the rotation of the rail bracket housing  24  about it, thereby. Rail bracket housing  24  is substantially hollow, being opened at its lower portion. A substantially round aperture  26  is formed through the clamp riser  22 . A second, substantially round aperture  28  is formed through rail bracket housing  24 . 
   A shaft  30 , having a diameter slightly smaller than that of the aperture  28 , extends through the apertures  26  and  28 , such that the shaft  30  may rotate within the apertures  26  and  28 . Aperture  26  has a diameter significantly larger than that of shaft  30 , as will be further explained hereinafter. Shaft  30  terminates, at a first end, in an aperture  32  formed in an opposite wall of the rail bracket housing  24 . At a mid portion of the shaft  30 , shaft  30  has a worm gear thread  34 . The worm gear thread  34  may, optionally, be an enlargement of the diameter of the shaft  30  (not shown). It would be evident to one of ordinary skill in the art that shaft  30  could easily terminate at the worm gear thread  34  in lieu of continuing to the opposite wall of the rail bracket housing  24  without departing from the spirit of the present invention. 
   At a second, free end, the shaft  30  extends through an aperture  62  in an upper end  62   u  of a suspension bracket  60  (to be further detailed, hereinbelow), terminating in an adjustment wheel  36  having a diameter greater than that of shaft  30 . Optionally, an adjustment knob  38  may be rotatably mounted proximate the perimeter of adjustment wheel  36 , to aid in a more delicate rotation of the adjustment knob  38 . Rotation of the adjustment wheel  36  causes rotation of the worm drive thread  34  of shaft  30 . 
   Two axles  40  pass through the opposite walls of the rail bracket housing  24  at points proximate the juncture of the lower surface of the rail bracket housing  24  and each of its two ends. A drive wheel  42  is situated at each end of each axle  40  within the interior of the rail bracket housing  24 . At the center of each axle  40  is a geared axle drive drum  44  having a diameter greater than that of the axles  40 , but less than that of the drive wheels  42 . A template  43 , configured to substantially match the shape of the upper surface of the railing  1000  extends along the length of the rail guide  20 , between the drive wheels  42 . The template  43  has a notch  41  cut into each of its four corners, thereby allowing space for each of the four wheels  42  to extend past the template  43 . Template  43  is held in place within the lower portion of the rail bracket housing  24  by at least one retractable clip  45  located proximate the bottom edge of the interior of each face of the rail bracket housing  24 , each clip  45  engaging a notch  47  in one of the side faces of the template  43 . 
   A central worm drive shaft  46  runs the length of the interior of the rail bracket housing  24  and has ends seated respectively within an aperture  48  situated within each of the two ends of the rail bracket housing  24 . At a central portion of the worm drive shaft  46 , the threads engage the worm drive threads  34  of the shaft  30 , while at a point proximate each of the two ends they engage the teeth of the gears of the axle drive drums  44 . Through this worm drive arrangement, rotation of the adjustment wheel  36  causes the worm drive thread  34  of shaft  30  to rotate. The worm drive threads  34 , in turn, cause the worm drive shaft  46  to rotate. Likewise, the worm drive shaft  46 , which engages the teeth of the axle drive drums  44 , which turn the axles  40  and the drive wheels  42 . 
   Proximate the lower end  22   l  of the clamp riser  22 , a pair of lower axles  49  extend substantially normal thereto and with one of the lower axles  49  substantially parallel to and below each of the axles  40 . An elongate roller  50  is rotatably mounted on each of the lower axles  49  such that each roller extends a distance substantially equal to or greater than that between the exterior of the pair of drive wheels  42  on the axles  40 . It would be evident to one of ordinary skill in the art that the rollers  50  could be a pair of wheels, similar to drive wheels  42 , without departing from the spirit of the present invention. 
   At the upper end  22   u  of the clamp riser  22  is a clamp bracket arm  52  which is offset from the clamp riser  22  such that an adjustment clamp  54  may be rotatingly attached thereto. The adjustment clamp  54  has a substantially rounded, non-symmetrical head  56  which rotates within the clamp bracket arm  52  and a handle  58  attached to the head. The non-symmetrical shape of the head  56  serves as a cam to cause compression against the upper surface of the bracket housing  24  as the adjustment clamp  54  is rotated such that the handle  58  comes down toward the bracket housing  24 . A slight flattening (not shown) of the head  56  may be used, thereby allowing the adjustment clamp  54  to lock against the upper surface of the bracket housing  24 , in the compressed position, forcing the bracket housing  24  downward and pulling the clamp riser upwards. By forcing the bracket housing  24  downward and the clamp riser upwards, the rail  1000  is compressed between the wheels  42  and the rollers  50 . The pressure thus exerted on the rail  1000  is such that the drill guide  1  is firmly maintained in a position along the length of the rail  1000 , yet rotation of the adjustment wheel  36  with adjustment clamp  54  released allows the rail guide  20  to roll along the rail  1000  being installed, to the location of each drilling site without removing the rail guide  20  from the rail  1000 . As stated hereinabove, the diameter of the aperture  26  in the clamp riser  22  is significantly larger than that of the shaft  30  in order to allow the shaft  30  to slide vertically within the aperture  26  as the adjustment clamp  54  is activated. 
   A suspension bracket  60  hangs, pivotally, from shaft  30 , and extends a long a side of clamp riser  22 , opposite the rail guide  20  assembly. The suspension bracket  60  is formed from a substantially rectilinear stock, and extends below the lower end  22   u  of the clamp riser  22 . The suspension bracket  60  has an upper end  60   u , which lies substantially along the length of the clamp riser  22 , and through which shaft  30  extends, as detailed hereinabove. Proximate the lower end of the clamp riser  22 , the suspension bracket  60  is angled downwardly and away from the clamp riser  22  in a mid portion  60   m . The suspension bracket  60  is again angled downwardly forming a lower end  60   l  which is substantially parallel to the upper end  60   u . A second aperture  64  is formed through the lower end  60   l  at a point proximate the end of the suspension bracket  60 . 
   A suspension bar  70  is rotatably mounted, at a first, upper end  70   u , at the lower end  60   l  of the suspension bracket  60 . Ideally, the upper end  70   u  of the suspension bar  70  is proximate the lower surface of the rail  1000  to be mounted, typically approximately 2.5 inches below the lower surface thereof. The suspension bar  70  is preferably rectilinear in shape to prevent rotation of a drill mount assembly  80  about the suspension bar  70 . The suspension bar  70  may be rotated about a bolt  72  and secured by a nut  74  which may be tightened to maintain the suspension bar in a plumb alignment regardless of the angle at which the rail is being installed. It would be evident to one of ordinary skill in the art that the bolt  72  could either pass through an aperture in the upper end  70   u  or affixed to a side of the suspension bar  70 . The nut  74 , preferably incorporates a hand knob to facilitate hand tightening. 
   Although not an element of the suspension bar  70  of the present invention, it would be evident to one of ordinary skill in the art that levels (not shown) could be incorporated into the suspension bar  70  to ensure a true plumb is achieved. 
   A drill mount assembly  80  ( FIG. 3 ) is movably mounted on the suspension bar  70 . Again, the rectilinear shape of the suspension bar  70  prevents rotation of the drill mount assembly  80  around the suspension bar  70 , limiting movement to a line along a longitudinal axis of the suspension bar  70 . 
   The drill mount assembly  80  consists of a drill mount bracket  82 , which fits moveably around the suspension bar  70  for vertical adjustment. In a preferred embodiment, a bolt  84  with a head  86  sufficiently large to allow hand tightening passes through an aperture in a face of the drill mount bracket  82  to engage a face of the suspension bar  70  to fix the drill mount assembly into a desired position. Optionally, a spring loaded pull pin (not shown) may be used to engage a series of apertures (not shown) spaced along the length of the suspension bar  70  to position the bracket  82  at selected, desired positions. A handle  83  may, optionally, be added to the drill mount bracket  82  to facilitate fine alignment of the drill guide manually. 
   In a preferred embodiment,  FIGS. 4 and 5 , the drill mount bracket  82  further includes a drill bracket back plate  91  with a pair of drill retention plates  90  hingedly mounted, via a hinge  93 , proximate the lower edge of the drill mount bracket back plate  91  such that they are substantially parallel to one another and lie beneath the rail guide assembly  20 . A drill retention ridge  92  is formed in the facing surfaces of each of the two drill retention plates  90 , the drill retention ridges  92  being adapted to be received in matching nylon lined grooves  102  formed in the sides of a drill  100  specifically adapted for use with the drill mount assembly  80  of the laser guided rail drill guide  1  of the present invention. The hinged feature of the drill retention plates  90  allow the drill retention plates  90  to be moved from their vertical orientation, as when in use, to a more horizontal orientation to facilitate installing the drill  100  into the drill retention plates  90 . The mating of the drill retention ridges  92  and grooves  102  of the drill  100  allow an easy, smooth installation/removal of the drill  100  into the drill retention plates  90 . 
   A drill advancement handle  94  is rotatably attached to the drill retention back plate  91 , in a geared relationship, such that as the drill advancement handle  94  is pulled, the drill attachment plates  90  move upwardly, advancing the drill  100  such that the bit  104  drills into the lower side of the rail  1000  being installed. The bit  104  engages the rail  1000  between the two sets of lower axles  48  and rollers  50 . 
   The mechanisms of drill presses are well known in the art and are not considered to be an inventive part of the present invention, therefore they will not be discussed in further detail herein. 
   In a simplest form of the inventive drill guide  1 , the drill  100 / 100 A may be turned on by simply engaging the switch  101  and locking it in the on position, as may be done with most drills. Alternatively, a switch  95 A/ 95 B incorporated into the gears  98  of the pivot point of the drill advancement handle  94  may provide power to the drill  100 / 100 A as drill advancement handle  94  is pulled to advance the drill  100 / 100 A from its lower, retracted position to its upper, engaged position, with a first contact  95 A making contact with a second contact  95 B as the handle  95 A is advanced. When the handle  94  is returned to the retracted position, the contact is broken and the power to the drill  100 / 100 A is terminated. 
   In order to prevent burring of the drilled hole, it is desirable to stop the rotation of the drill bit  104  at the maximum desired depth of the drilled hole. In order to achieve this, the switch of  FIG. 6  may be designed to open when the drill  100 / 100 A is fully advanced (not shown), or a clutch  120  may be built into the drill  100 / 100 A or installed into the chuck of the drill  100 / 100 A. DeWalt International Tool Company currently manufactures a clutch, model number DW257, which is well suited to this purpose, therefore the details of the clutch  120  will not be further discussed. 
   A laser mount plate  110  is fixedly attached to the suspension bar  70 , substantially normal thereto and below the drill mount assembly  80 . A laser device  112  is attached to the laser mount plate such that the laser projects a beam  114  downwardly along a line coincidental with the line of axis of travel of the drill  100 / 100 A and bit  104 . A true alignment of the point of drilling of the rail and the tread below is ensured through the alignment of the bit  104  and laser beam  114 . Power to the laser  112  may be constant, or a switch  116  may be incorporated into the laser  112 , thereby allowing the laser to be turned off when not needed. 
   Power to the switch  95 A/ 95 B and laser  112  may be provided through the drill  100 / 100 A unit or through a power box within the drill mount assembly  80  with equal effectiveness, and may vary from one embodiment of the present invention to another. However, in a preferred embodiment, a female electrical plug  104  is incorporated into the base of the drill  100 A in a position which allows connection to a male plug  96  formed in the base of the drill mount assembly  80 , the male plug  96  being in a wired relationship to the laser  112 . This female  104 /male  96  plug allows an electrical connection from the drill  100 A to the laser  112 . 
   When in use, the shank of the drill  100 / 100 A, bit  104  and laser  112  lie along a common axis A ensuring proper alignment of the holes in the railing and the riser below. 
   In use, a template  43  corresponding to the contour of the upper surface of the rail  1000  mounted between the drive wheels  42  of the rail guide  20 , and then the rail guide  20  is placed atop the rail  1000 , with drive wheels  42  atop the rail  1000  and the rollers  50  below the rail  1000 . The adjustment clamp  54  is used to draw the rollers  50  tightly against the bottom of the rail  1000 , holding the rail guide  20  firmly, but movably in place. 
   After the rail guide  20  has been mounted, the suspension bar  70  is adjusted such that it hangs vertically from the rail guide, with the drill mount assembly in a position such that the tip of the bit  104  of the drill  100 / 100 A is just below the lower surface of the rail  1000 . Since the drill bit  104  and the laser  112  lie along a common axis, the bit  104  is now aligned with a beam projected onto the tread below, allowing drilling of the railing and marking of the point for later drilling the tread to align a with the hole formed in the railing  1000 . As in typical drill press assemblies, the drill advancement handle  94  raises and lowers the drill  100 / 100 A and thus the bit  104  to drill the underside of the rail  1000 . 
   After each hole is drilled in the rail  1000  and the tread below is marked, the rail guide may easily be moved along the length of the rail  1000  by turning the adjustment wheel  36  which turns the drive wheels  42  which traverse the top of the rail  1000  to the next drilling site. Conversely, the drilling locations may be laid out on the tread and the drilling location in the railing  1000  located by aligning the laser on the laid out points. 
   It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.