Patent Document

BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to work benches. More specifically the present invention relates to a work bench for assembling stair stringers. 
     2. Discussion of the Related Art 
     A typical staircase is comprised of an alternating series of treads and risers that form the individual steps of the staircase. The treads, and in most cases the risers, are supported by a pair of stair stringers that form part of the staircase structure. Stair stringers are frequently constructed at a construction worksite where the staircase is to be constructed. 
     To construct a typical stair stringer, a carpenter will “layout” a stair stringer by marking a single 2×12, 2×14 or other sized piece of lumber with layout lines. The layout lines identify the contour or shape of the stair stringer. The shape of the stair stringer generally comprises an elongated beam with multiple triangular edges that support the individual treads and risers. The carpenter saws along the layout lines that define the triangular edges leaving a stair stringer. The carpenter will then usually dispose of the remaining pieces of lumber as waste. 
     A matching stair stinger is constructed similarly. The carpenter carefully marks a single piece of lumber with layout lines and saws a complementary stair stringer from the single piece of lumber. The carpenter typically disposes of the remaining lumber as waste. The stair stringer and the matching stair stringer are then installed parallel to each other. Treads and risers are attached to the pair of stair stringer forming a staircase. 
     It can be appreciated that the carpenter must carefully layout and saw the stair stringer and matching stair stringer to allow accurate placement of the treads and risers. It can also be appreciated that the task of cutting stair stringers from a single piece of lumber is a time consuming task; particularly, since most carpenters at a worksite spend a very small proportion of their time at this task. Moreover, lumber waste is an undesirable residue of this process. 
     Those skilled in the art will recognize that there is a need for an apparatus that allows a carpenter to: quickly, easily and accurately construct the stair stringers of a staircase with little lumber waste. It can also be appreciated that an apparatus that can be used to make stair stringers at a lumberyard would allow carpenters to specialize in constructing stair stringers, allowing mass production of stair stringers for multiple construction worksites. Applicant&#39;s invention addresses these needs as well as other needs. 
     SUMMARY OF THE INVENTION 
     In one embodiment, the invention can be characterized as a stair making apparatus, comprising: a bench adapted to support a plurality of members and a beam; a stop fixture connected to the bench, the stop fixture having a plurality of stops for individually engaging each of the plurality of members; and one or more fasteners connected with the bench, the one or more fasteners configured to cooperate with the plurality of stops to brace the beam and the plurality of members in a form of a stair stringer. 
     In a further embodiment, the invention may be characterized as a stop fixture for making stair stringers, the stop fixture comprising: a rotatable shaft having a first threaded end and a second threaded end, a first stop coupled to the first threaded end of the rotatable shaft, the first stop for engaging a first member; and a last stop coupled to the second threaded end of the rotatable shaft, the last stop for engaging a last member. 
     In still another embodiment, the invention may be characterized as a stop fixture for making stair stringers, the stop fixture comprising: a shaft; a first stop coupled to the shaft for engaging a first member; a second stop adjacent to the first stop and coupled to the shaft at a predetermined distance from the first stop, the second stop for engaging a second member; a third stop adjacent to the second stop and coupled to the shaft at the predetermined distance from the second member, the third stop for engaging a third member; and means for translating the second stop and the third stop, wherein when the second stop and the third stop are translated a first distance between the first stop and the second stop remains substantially equal to a second distance between the second stop and the third stop. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features and advantages of several embodiments of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings. 
         FIG. 1  shows an illustration of a stair stringer assembly bench supporting a beam and a plurality of members configured in the form of a stair stringer according to an embodiment of the invention. 
         FIG. 2  shows an illustration of a stair stringer assembly bench supporting the beam and the plurality of members shown in  FIG. 1 , the plurality of members coupled to the beam with ties according to an embodiment of the invention. 
         FIG. 3  shows an illustration of a stair stringer assembly bench supporting the beam and the plurality of members shown in  FIG. 2 , the beam and the plurality of members flipped and configured for application of ties on an opposite side. 
         FIG. 4  shows a schematic of an exemplary beam and a plurality of members used to produce a stair stringer according to an embodiment of the invention. 
         FIG. 5  shows an exploded view of a stair stinger assembly according to an embodiment of the present invention. 
         FIG. 6  shows a stop fixture according to an embodiment of the present invention. 
         FIG. 7  shows an exploded view of a stop fixture according to an embodiment of the present invention. 
         FIG. 8  shows a shaft wheel and a spacing indicator according to an embodiment of the present invention. 
         FIG. 9  shows a stop according to an embodiment of the present invention. 
         FIG. 10  shows a press according to an embodiment of the present invention. 
         FIG. 11  shows the press of  FIG. 10  pressing a tie according to an embodiment of the present invention. 
     
    
    
     Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. 
     DETAILED DESCRIPTION 
     The following description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of exemplary embodiments. The scope of the invention should be determined with reference to the claims. 
       FIGS. 1-3  show illustrations of a stair stringer assembly bench supporting a beam and a plurality of members configured in the form of a stair stringer. Specifically,  FIG. 1  shows an illustration of a stair stringer assembly bench supporting a beam and a plurality of members in the form of a stair stringer before metal ties have been used to fasten the plurality of members to the beam  100 .  FIG. 2  shows an illustration of a stair stringer assembly bench supporting a beam and a plurality of members after metal ties have been used to fasten the plurality of members to the beam  200 .  FIG. 3  shows an illustration of a stair stringer assembly bench supporting a beam and a plurality of members flipped and configured for the application of ties to the other side of the stair stringer  300 . 
     The stair stringer assembly bench  102  shown in  FIGS. 1-3  includes a stop assembly  104 , a pneumatic press  106  and a plurality of fasteners  108 . The stair stringer assembly bench  102  also has a left support  110  and right support  112 . The stop assembly  104  includes a hand wheel  114 , a positioning tape  116 , and a plurality of stops  118 . On top of the stair stringer assembly bench  102  is a beam  120  and a plurality of members  122 . In  FIG. 2 , a plurality of ties  202  are affixed to the beam  120  and the plurality of members  122 . 
     The stair stringer assembly bench  102  supports the beam  120  and the plurality of members  122 . The plurality of stops  118  in this embodiment are spaced uniformly and are shaped to engage the substantially right angle tips of the plurality of members  122 . The plurality of stops  118  cooperates with the plurality of fasteners  108  to secure the plurality of members  122  and the beam  120  in the form of a stair stringer. In this and many other embodiments the hand wheel  114  is operable to uniformly adjust the distance between stops allowing the carpenter to increase or decrease the separation between the plurality of members  122 . This provides the bench with the capability to accommodate different sizes and shapes of beams and members for a variety of different types and sizes of stair stringers. 
     A positioning tape  116  in many embodiments allows the carpenter to easily inspect the distance between members. Markings may be used in conjunction with the position tape place to show typical distances or indicate appropriate stop positions for a variety of different sizes and types of stair stringers. The positioning tape  116  thus may be used by the carpenter to quickly adjust the stop distances using the hand wheel  114 . 
     Those skilled in the art will readily recognize that there are many alternative embodiments that include different stop separation measuring features. For example, some embodiments feature a meter mechanically connected to the hand wheel that provides numeric indicia of the separation between the plurality of stops  118 . Other embodiments feature no positioning tape  116  or measuring device. 
     In this embodiment, the fasteners  108  are wing nut clamps and the plurality of stops  118  have embedded springs. The wing nut clamps can be tightened forcing the beam  120  and the plurality of members  122  up against the plurality of stops  118  compressing the embedded springs and bracing the beam  120  and the plurality of members  122  in the form of a stair stringer. 
     Alternate embodiments feature different types of fasteners  108  and stops. In some embodiments the plurality of stops  118  do not include embedded springs. In some embodiments the fasteners  108  are spring loaded. In some embodiments the stair stringer assembly bench  102  features grooved edges and cutouts for securing the beam  120  to the plurality of members  122 . 
     In this embodiment, the pneumatic press  106  is slide-ably mounted on the stair stringer assembly bench  120 . The pneumatic press  106  can be moved along the bench as can be seen by the different positions of the pneumatic press  106  in  FIGS. 1 and 2 . This allows the carpenter to easily position the pneumatic press  106  and press ties  202  over appropriate portions of the beam  120  and the plurality of members  122 . The pneumatic press  106  can then be used to press the ties into the beam  120  and the plurality of members  122  as shown in  FIG. 2 . The fasteners  108  may then be loosened to allow a carpenter to flip the beam  120  and the plurality of members  122  as shown in  FIG. 3 . The carpenter can then easily push the beam  120  up against the plurality of stops  118  allowing the carpenter to use the pneumatic press  106  to apply ties to the other side of the stair stringer form further securing the beam  120  to the plurality of members  122 . 
     In alternate embodiments, the pneumatic press  106  is embodied as a mechanical, hydraulic or other type of press. Still other embodiments feature no press at all with the carpenter securing the beam  120  to the plurality of members  122  with other fastening products such as glue, non-press ties or the like. The use of both metallic and nonmetallic ties in conjunction with the stair stringer assembly bench  120  is contemplated. 
     The left support  110  and right support  112  can be used to hold the beam  120  or in other embodiments a plurality of beams. A convenient use of the left support  110  and right support  112  is manifest by placing the beam  120  in the supports before the plurality of members  122  are placed on the plurality of stops  118 . The beam  120  may then easily be lifted, rotated into place and secured with the fasteners  108  as shown in  FIG. 1 . 
     It can be appreciated that the stair stringer assembly bench can be used to quickly and accurately assemble a stair stringer. The carpenter adjusts the plurality of stops  118  using the hand wheel  114 . He then places the plurality of members  122  into the plurality of stops  118 , lifts and rotates the beam  120  into place and uses the pneumatic press  106  to apply ties to secure the beam  120  to the plurality of members  122 . The carpenter then flips the resulting stair stringer form and pushes the beam  120  against the plurality of stops  118  and applies ties to the other side of the stair stringer form completing the stair stringer. 
     Those skilled in the art will recognize that the stair stringer assembly bench may be used in an assembly line fashion. Lumberyards and other retailers can use the assembly bench to mass produce stair stringer assemblies for contractors saving the contractors time, effort and money. 
       FIG. 4  shows a schematic of an exemplary beam and a plurality of members  400  used to produce a stair stringer according to an embodiment of the invention. The beam  120  used to form the stair stringer has an “A” dimension  402  and a “B” dimension  404 . Each of the plurality of members  122  has a riser dimension  406  and a tread dimension  408 . The riser dimension  406  and the tread dimension  408  determine a step to step dimension  410 . The step to step dimension is important because it determines the stop to stop separation that the carpenter should use when using the stair stringer assembly bench (not shown). A precut riser dimension  412  and tread dimension  414  are also shown. 
     To construct the members of the stair stringer, the riser dimension  406  and tread dimension  408  are determined. In this exemplary case, the riser dimension  406  and the tread dimension  408  are both 9.0 inches. The riser dimension  406  of 9.0 inches and the tread dimension  408  of 9.0 inches results in a step to step dimension of about 12.75 inches. The step to step dimension for different riser dimensions and tread dimensions can be calculated using the Pythagorean Theorem.
 
Step to Step Dimension=Square root of [(riser dimension) 2 +tread dimension squared) 2 ]
 
     To fashion two of the plurality of members  122  the carpenter can cut a rectangular piece from corner to corner. The rectangular piece should have a precut riser dimension  412  and tread dimension  414  that accounts for cutting loss. In this case, the precut riser dimension  412  and the precut tread dimension  414  are both 9.07 inches. 
     In this example, the riser dimension  406  and tread dimension  408  are the same. However, the calculations are equally valid for stair stringers having different sized treads and risers. 
     Dimension A  402  represents the upper portion of the stair stringer that will extend beyond the risers and the treads. Dimension B  404  represents the lower portion of the stair stringer that will extend beyond the risers and the treads. Those skilled in the art will recognize that the carpenter assembling the stair stringer should know either dimension A  402  or dimension B  404  when assembling the stair stringer, to insure proper alignment of the  120  beam with the plurality of members  122  on the stair stringer assembly bench (not shown). 
       FIG. 5  is an exploded view of a stair stinger assembly  500  according to an embodiment of the present invention. A left bench support  502  and a right bench support  504  are shown. Strung between the left bench support  502  and the right bench support  504  are a front panel  506 , a top surface  508  and a back surface  510 . A sliding mount  512  is slide-ably mounted on the back surface  510 . The sliding mount  512  rotate-ably supports the pneumatic press  106 . The top surface  508  has a lip  514  that extends upward to prevent the stop fixture  104  from rotating when the plurality of stops  122  is engaged by the plurality of members (not shown). 
     Those skilled in the art will recognize that this is an exemplary embodiment of the stair stringer assembly bench and that in other embodiments some of the parts shown may be embodied as different structures or their function may be incorporated in other parts. 
       FIG. 6  shows an illustration of an exemplary stop fixture according to an embodiment of the present invention  600 . The stop fixture  104  has a shaft  602  that is connected to a hand wheel  114 . Connected to the shaft  602  is a plurality of stop assemblies  604  that support the plurality of stops  118 . Stop plates  606  are arranged around a first stop assembly  603  and a last stop assembly  605 . A panagraph  608  connects each of the plurality of stop assemblies  604  including a first stop assembly  603  and a last stop assembly  605 . The shaft  602  has a threaded section  610  that extends between stop plates  606  arranged around the first stop assembly  603 . The shaft  602  also has a reverse threaded section  612  that extends between stop plates  606  arranged around the last stop assembly  605 . 
     In this embodiment, turning the hand wheel  114  rotates the shaft causing the first stop assembly  603  to translate along the threaded section  610  and causing the last stop assembly  605  to translate along the reverse threaded section  612 . This results in the panagraph  608  expanding or contracting depending on the direction of rotation of the hand wheel  114 . The expansion or contraction of the panagraph  608  causes the plurality of stop assemblies  604  to move sympathetically. As the stop assemblies  604  move sympathetically, the distances between the plurality of stops  118  changes synchronously and uniformly. 
     Those skilled in the art will recognize that this synchronous and uniform change allows a carpenter to easily adjust the distance between the plurality of stops  118 . The distance can thus easily be set to the step to step distance of the stair stringer. After setting the distance the carpenter can quickly and easily place the plurality of members (not shown) flush against the stops. 
       FIG. 7  shows an exploded view of a stop fixture according to an embodiment of the present invention  700 . In this embodiment, the stop fixture  104  has a first stop plate  704 , a second stop plate  706 , a third stop plate  708 , a fourth stop plate  710 , a fifth stop plate  712  and a sixth stop plate  714 . A first hand wheel  716  and a second hand wheel  718  are also provided. The first hand wheel  716  is connected with a first shaft segment  720 , that is connected with a second shaft segment  722  having threads (not shown), that is connected with a third shaft segment  724 , that is connected with a fourth shaft segment  726  having opposite threads (not shown) as the second shaft segment  722 , that is connected with a fifth shaft segment  728  that is connected with the second hand wheel  718 . The shaft segments are supported in the stop fixture  104  by flange bearings  730 . The shaft segments are mutually connected a plurality of shaft couplings  740 . Stop assemblies  742  ride on the shaft segments with a first stop assembly riding on the second shaft segment  722 , a last stop assembly riding on the fourth shaft segment  726  and the other stop assemblies riding along the third shaft segment. A panagraph constructed from bars  744  and pins  746  is coupled to the stop assemblies  742 . The stop assemblies  742  are arranged such that each stop assembly is equidistance from another stop assembly. 
     It can be readily recognized that the parts used to construct stop fixture  104  are exemplary and that other embodiments feature different designs and structures that allow a carpenter to easily adjust the distance between the plurality of stops  118 . 
       FIG. 8  shows a shaft rotation assembly and a meter assembly according to an embodiment of the present invention  800 . The shaft rotation assembly  802  is connected with the meter assembly  804 . The shaft rotation assembly  802  includes a hand wheel  806  that has a rotation gear  808 . The meter assembly  804  has a meter gear  810  that is connected with the rotation gear  808 . The meter assembly  804  also includes a display  812  and a reset button  814 . 
     When a carpenter turns the hand wheel  806  the rotation gear  808  turns proportionately. The rotation gear  808  turns the meter gear  810  as well as the shaft supporting the stop assemblies (not shown). The display  804  shows the amount of movement of the stop assemblies connected to the shaft. A reset button  814  allows the carpenter to reset the display value to a nominal value. Using the shaft rotation assembly and meter assembly  800  the carpenter can easily adjusts the relative distances between stops allowing the carpenter to set the appropriate step to step distance for the stair stringer the carpenter is assembling. 
       FIG. 9  shows a stop  900  according to an embodiment of the present invention. The stop  900  has a base  902  and a head  904 . The head  904  has a contoured tip  906  adapted to accept the edge of a member (not shown). The base  902  and the head  904  are connected via a pair of shoulder bolts  908  and a spring  910 . 
     The spring  910  applies a force to the base  902  and the head  904 . The force separates the base  902  from the head  904  when the stop  900  is in its quiescent state. When the edge of one of the plurality of members (not shown) is pressed up against the contoured tip  906 , a force is applied the spring  910  compressing the spring  910  and applying a reaction force to the member. As explained above, the stop  900  cooperates with the plurality of fasteners  108  to hold the beam (not shown) and the plurality of members (not shown) in the form of a stair stringer. 
       FIGS. 10-11  show a pneumatic press according to an embodiment of the present invention. Specifically  FIG. 10  shows the pneumatic press  106  in its quiescent position  1000 .  FIG. 11  shows the pneumatic press  106  in its press position  1100 . 
     The pneumatic press  106  is generally U shaped and is attached to a mount  1002  via a pin  1004 . The mount  1002  is slide-ably attached to the stair stringer assembly bench  102 . The mount  1002  has a rotation guide  1006  proximate to the pneumatic press  106 . The pneumatic press  106  includes a piston chamber  1008  surrounding a piston  1012  that terminates in a press  1010 . The piston chamber  1008  and the piston are mounted via a rotating joint  1013 . In complementary relationship with the press  1010  is a rotating anvil  1014 . 
     Apparent in  FIGS. 10-11  is one of the plurality of fasteners  108  cooperating with the one of the plurality of stops  118  to secure the beam  120  and the one of the plurality of members  122  in the form of a stair stringer. Also apparent is the stop fixture  104  and the hand wheel  114  more fully described above. 
     In operation, air forces the piston  1012  down on to one of the plurality of ties  202 . The force causes the rotating joint  1013  to rotate and the rotatable anvil  1014  to swivel substantially normal to the applied force. In addition, the pneumatic press  106  rotates relative to the mount via pin  1004  and is guided by the guide  1006 . The rotating joint  1013 , the rotating anvil  1014  and the pin  1004  cooperate and insure that most of the pneumatic forces during operation are distributed throughout the pneumatic press  106  with only a small amount of force being transferred the stair stringer assembly bench. 
     While the invention herein disclosed has been described by means of specific embodiments, examples and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.

Technology Category: 4