Abstract:
Disclosed is an apparatus for precisely, easily and automatically setting and resetting stops on a cutting table. In particular, a hand manipulable pointer slideable along a scale may be moved a desired and equal distance to that desired of the stops, and the stops will automatically move that same distance and direction. The system is accomplished by operatively coupling the stops and the pointer system to a linear actuator. Also disclosed is an electromechanical braking system of superior quality for this apparatus.

Description:
FIELD OF THE INVENTION 
     The field of this invention relates generally to automated cutting or sawing systems. In particular, the field of this invention relates to automated precision metering means or stop manipulation for a tabletop cutting system. 
     BACKGROUND OF THE INVENTION 
     Cutting systems such as that depicted in FIG. 2 (prior art) have been around for some time, as gleaned from the Speed Cut, Inc. brochure. However, advances in the stop positioning systems of such cutting systems have been limited. There are numerous drawbacks to prior art metering or stop positioning systems such as that depicted in FIG.  2 . For instance, the time it takes to manually change a desired length of a cut from, say, one foot, six inches to one foot, eight inches, or five feet, six inches to five feet, eight inches, is limited by the dexterity of the user of the apparatus vis-a-vis crank C and handle H. Certainly, as can be seen in large scale operations, time lost in repositioning a system such as this over the course of high usage results in unnecessary labor costs. 
     Another drawback of the prior art system of FIG. 2 is that, upon repeated use wherein workpieces are forcefully pushed against the stops S, the stops S tend to creep from their desired position to an undesired position, resulting in undesired cutting lengths. This is true of such prior art devices even if a brake is employed because prior art brakes have been inadequate for repeated, rough treatment from users. Of course, this also results in having to readjust the stop position from time to time due to the movement of the stop positions. Corollarily, this also results in a user having to check those stop positions periodically to ensure that they are accurately set. Again, this results in a serious waste of labor, time and money over the long haul. 
     Again, where we are considering a system such as that depicted in FIG. 2, we are looking at an industrial or shop setting wherein that system is intended for high volume usage. By further automating wood or metal cutting or other workpiece cutting as it relates to such a tabletop cutting apparatus, certain efficiencies can be achieved which the prior art is incapable of at the present. 
     The following prior art reflects the state of the art of which applicant is aware and is included herewith to discharge applicant&#39;s acknowledged duty to disclose relevant prior art. It is stipulated, however, that none of these references teach singly nor render obvious when considered in any conceivable combination the nexus of the instant invention as disclosed in greater detail hereinafter and as particularly claimed. 
     OTHER PRIOR ART (Including Author, Title, Date, Pertinent Pages, Etc.) “Turntable Cutting System”, Speed Cut, Inc., date unknown, entire brochure (4 pages). 
     SUMMARY OF THE INVENTION 
     Generally speaking, the instant invention is an automated precision metering means for defining workpiece cut lengths. A plurality of spaced stops may be precisely relocated by a linear electric motor means by merely repositioning a pointer on a scale. Correspondingly, the distance displaced by the pointer on the scale will be the resulting equal distance of displacement of the linear motor means and therefore the stops. This is accomplished via a closed-loop circuit design which causes motor action that follows, precisely, pointer displacement. That is, a two inch movement of the pointer on a scale by the hand of a user (really the touch of a finger) will result in a guide rail, and therefore all stops attached thereto, to move that same distance in that same direction. 
     Additionally, a braking system is likewise disclosed so that once a desired position for the stops is located, that position is held fast; this is so even after repeated workpiece collisions with the stops. An electromechanical braking system is capable of withstanding forces in excess of those commonly experienced for such an apparatus (i.e., slamming workpieces into stops). 
     OBJECTS OF THE INVENTION 
     The primary object of the present invention is to automate the process of relocating the stop positions for a predetermined length cutting apparatus. 
     Another overall object of the present invention is to provide such an automated system wherein, once the stops are relocated to a desired position, the stops remain fixed in their position until relocation is again desired. 
     It is another object of the present invention to provide an automated stop relocation system. 
     It is another object of the present invention to utilize a linear motorized means to relocate stops. 
     It is another object of the present invention to use an electric braking system to prevent the stops of the present invention from dislocating from desired points. 
     It is another object of the present invention to provide a precise metering system whereby displacement is accomplished by sliding a pointer on a scale. 
     Viewed from a first vantage point, it is an object of the present invention to provide a cutting apparatus, comprising, in combination, a saw, a table extending from and beneath the saw, a plurality of workpiece abutment means extending upwardly and outwardly from a top surface of the table, means for automatically repositioning the stops, the automatic repositioning means operatively coupled to the stops. 
     Viewed from a second vantage point, it is an object of the present invention to provide a method for precisely specifying the length of a cut for a workpiece on a table saw, the steps comprising, in combination, orienting a pointer on a scale in the direction and distance desired for a cut length change, driving a guide having a plurality of spaced stops thereon correlative to the orientation of the pointer. 
     Viewed from a third vantage point, it is an object of the present invention to provide a table saw automatic stop adjustment kit, comprising, in combination, guide rail means coupleable to the table, a plurality of stops coupled to the guide, electromechanical reorientation means operatively coupled to the guide for adjusting the stops on the table. 
     These and other objects will be made manifest when considering the following detailed specification when taken in conjunction with the appended drawing figures. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a tabletop cutting apparatus of the instant invention. 
     FIG. 2 is a prior art tabletop cutting apparatus. 
     FIG. 3 is a backside view of the tabletop cutting apparatus depicting the metering means components. 
     FIG. 4 is a top view of that which is shown in FIG.  3 . 
     FIG. 5 is a top view of the rail and gantry system of the instant invention. 
     FIG. 6 is a side view of the rail and gantry system of the instant invention. 
     FIG. 7 is a bottom view of the rail and gantry system of the instant invention. 
     FIG. 8 is an enlarged view of the gantry on the rail with one switch in a closed position. 
     FIG. 9 is a schematic of the instant invention. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Considering the drawings, wherein like reference numerals denote like parts throughout the various drawing Figures, reference numeral  10  is directed to the automated stop positioning system according to the present invention. 
     Generally speaking, the instant invention consists of the following components: a pivotable saw  12 ; a table  14 ; a guide  22  having stops  24  thereon; a linear actuator  26 ; a motor  44 ; an electromechanical brake  106 ; a power source  108 ; and a user positioning interface  30  having switches  70 ,  72  operatively coupled therein. Although these are the general components of the instant invention, details and interrelations of these components will be described hereinbelow. Although the workpieces for the cutting system may be wooden planks or metal, the following will generally describe the table associated with such a system for any such workpieces. 
     Referring now to FIG. 1, a table  14  is supported by legs  16  having a pivotable saw  12  at one end thereof. Although the workpiece support surface is to the left of the saw  12 , this invention works equally well with a right hand system. Rollers  18  spaced and interposed upon table  14  allow a workpiece to be positioned along and atop table  14  in abutment with any of stops  24 . By positioning a workpiece along the table  14  and beneath the saw  12 , the workpiece is in a position to be cut. When a user, however, wishes to make repeated and equal cuts of workpieces on such a table  14 , it is desirable to have some form of a jam, such as a stop  24 , to abut against the workpiece. A plurality of stops  24 , such as depicted in FIG. 1, is preferable, so that the stops  24  may be equally spaced, by, for example, one foot, so that various lengths can be readily chosen. Of course, the stops  24  must be in a fixed, non-slipping, position to allow multiple equal cuts to be made. However, it is also desirable to freely and readily relocate the position of such stops  24  for a next or other set of precisely metered cuts. 
     Referring now also to FIGS. 3 and 4, to that end, stops  24  are provided in a pivotally coupleable relationship to guide rail  22 . However, in the instant invention, the guide rail  22  is not itself affixed to table  14 . Instead, an L-shaped support  100  is coupled to table  14  and guide rail  22  rests upon slider pads  102  (preferably plastic disks) in a low frictional engagement with L-shaped support  100  by means of guide mounts  42  which are also L-shaped. Slider pads  102  are fastened to the L-shaped support  100 . Guide mounts  42  are fastened on one side to guide rail  22  and are in low frictional engagement with the back side of L-shaped support  100  via slider pads  102 . These low friction slider pads allow the guide rail  22  to slide back and forth as required in a low friction environment with a low level of initial force required. 
     To move the guide rail  22  back and forth, the guide rail is coupled to a linear motor means or linear actuator  26  by a rod- or bar-shaped coupling  28 . Linear electric motors are very much like rotary electric motors, but while a rotary motor uses forces to twist a rotor around in a circle, a linear motor uses forces to push a carriage or rod along a track or tube. The linear actuator  26  as depicted in the drawing figures is a telescoping linear actuator wherein a rod arm  104  extends from a sleeve or retracts into the sleeve. A variety of linear actuators may be utilized for this purpose, however, a linear actuator having a 12 inch to 36 inch stroke of the rod arm is preferred, and 18 inches is most preferred. The linear actuator also preferably can accommodate at least a 250 pound load and most preferably can accommodate a 500 pound load. By forward or reverse pulsing of motor  44  (by, for instance, a switching means described in more detail hereinafter below), which is operatively coupled to the linear actuator  26 , the linear actuator will likewise either retract or extend while a current is pulsing therethrough as will now be evident to those having ordinary skill in the art, informed by the present disclosure. 
     In physical relationship to the tabletop of the apparatus described hereinabove, the linear actuator  26  is coupled to a circuit box  46  which is itself coupled to both L-shaped support  100  and table  14 . The coupling between the circuit box and the actuator  26  includes a fastener and a spacer to so locate the actuator  26  in space in substantially axial or parallel alignment with guide rail  22 . Circuit box  46  is a housing for containing ancillary circuit components and power cables  56 . Also both mechanically and operatively coupled to the linear actuator  26  is a rectangular box  30 , which is the effective user interface for movement of the actuator  26  in a desired direction by a user. The details of that operation will follow below. 
     The rectangular box  30  is coupled to and positioned from linear actuator  26  by means of fasteners  27  (FIG. 6) project the rectangular box in space at a height at which an average user could both view the face of box  30  and manipulate it by hand. On the face of box  30 , in sight of a user of the invention, is a scale  40  and a knob  38  having a pointer  36  thereon in pointing relationship to scale  40 . Scale  40  can be of a multitude of scale varieties depending on the preference of a user, and is interchangeable at any time by a user with another scale. A foot-and-inch scale, although preferred, is not necessarily required. A left or right handed scale  40  is provided depending on whether table  14  projects from the left or right of the saw  12 . As long as a user can discern, by means of the pointer  36  and its relationship to the scale  40 , the desired distance by which that user wishes to move the guide rail  22  in a desired direction, precise movement of guide  22  may be accomplished. 
     Internal to the box  30  is a rail and gantry system. The components of this system are best viewed in FIGS. 5 through 8. In particular, the rail and gantry system is composed of a rail  92  that is engageable with bearing means, preferably V-shaped bearings,  94 , though other bearing means are available to perform this task. Rail  92  is complimentarily formed to so receive V-shaped bearings  94  or other bearings as necessary. It is intended that a gantry or carrier  90  be slideably coupled to the rail  92  by means of the rail bearings  94  so that the gantry or carrier  90  can travel freely (low friction) along the rail  92 . To hold the rail  92  in place, but also allow it to travel within box  30 , are provided slideable rail mounts  96  which are coupled along with box  30  to linear actuator  26  as described above. Slideable rail mounts  96  also include a pair of V-shaped bearings  94  to so allow free travel of rail  92  thereby. 
     Carried on the carrier or gantry  90  will be two switching means, or microswitches  70  and  72 , preferably operatively coupled to relays and transformer within circuit box  46  as will be evident to those having ordinary skill in the art, informed by the present disclosure. Also mounted on the rail  92  are a right cam guide  74  and a left cam guide  76  (fastened thereto with cam fasteners  78 ) which are provided to operatively interact with microswitches  70 ,  72 . Although the left and right cam guides  76  and  74  are substantially running through a center line of the rail, they are actually offset from each other slightly, so that they can operatively engage with microswitches  70  and  72 , respectively. More particularly, each of those microswitches  70  and  72  has a biased contact  82  in close proximity with or contacting right and left cam guides  74  and  76 . The slight displacement of the cam guides  74 ,  76  vis-a-vis each other is substantially equal to the throw of the switch contacts  82 . That is, as shown in FIG. 8, left cam guide  76  is spaced such that it will operatively engage or close switch  70 , but cannot engage switch  72  and hence switch  72  stays in an open position when traveling by cam guide  76 . The same is true in a mirrored relationship for right cam guide  74  and switch  72 . 
     A space is also provided between the cam guides substantially equal to the distance between the biased contacts  82  of the respective left and right microswitches  70  and  72  when considered axially along rail  92 . That space is adjustable by means of an adjustment screw  80  so that the desired space can be tuned precisely. When the biased contacts  82  of the respective microswitches  70  and  72  are in the open area  88 , a rest position is attained wherein the biased contacts are extended and cause the switches  70 ,  72  to be open. Conversely, if the gantry  90  is moved to the right (of FIG.  8 ), for instance, microswitch  72  and its biased contact  82  will come into contact with cam  74 , causing the switch to close. However, microswitch  70  and its corresponding biased contact  82  will not contact cam  74  due to the slight offset of the cams mentioned hereinabove. As the cams and microswitches are in a mirrored symmetric relationship left to right on the rail, the same is true if we were to take the gantry along the rail to the left. 
     As can also be seen in FIGS. 5 through 8, each microswitch  70  and  72  has a pulse terminal  84  and a ground terminal  86  and corresponding wires running therefrom through a preferably coiled cable  48  as depicted therein and running out from box  30  to circuit box  46 . Also preferably running within the center core of coiled cable  48  is air hose  50  which also runs back to circuit box  46  and is coupled to an air supply which allows constant air displacement within box  30  to prevent debris from settling therein. 
     In actuality, the gantry  90  moves relative to the rail  92  in use, and the rail  92  also moves relative to the gantry  90 . This will now be described. At the end of a cam  76  is a rod  32  coupled thereto and extending therefrom and outward from box  30 . That rod is coupled to the rod arm  104  of linear actuator  26  by a rod coupling means  34 . Therefore, as is now apparent, as the linear actuator rod arm  104  extends and retracts from within the linear actuator  26 , likewise the rod  32  will move the rail  92  left and right with respect to slideable rail mounts  96 . Box  30  also contains an elongated cavity below scale  40 . Knob  38  extends into and through that cavity and is coupled to gantry  90  (FIGS. 6 and 7) at fastening holes  110  so that when the knob  38  is moved left or right, the gantry  90  likewise moves left or right along the rail  92 . 
     As now can be understood, in use and operation, when a user wishes to adjust the position of the plurality of stops  24 , a user by hand will grasp knob  38  and move it the desired number of inches or metered position left or right along scale  40 , thereby engaging the left or right microswitch  70  or  72 , which are operatively coupled, each in opposite polarity to motor  44 , causing motor  44  to likewise pulse forward or reverse, which as described above will cause linear actuator  26  to extend or retract in the desired direction for the desired distance. The desired distance is accomplished by the following. When the gantry  90  is moved by moving the knob  38 , say to the left one inch, microswitch  70  will close due to its biased contact  82  engaging cam guide  76 . Thereafter, while that microswitch is in a closed position, current will continue to run to motor  44  until linear actuator  26  pulls rod  32  and hence rail  92  left one inch, thereby causing microswitch  70  to open and stop current from flowing when its biased contact  82  falls into opening or rest area  88 . One might describe this type of electromechanical circuitry as an electromechanical, closed-loop following system due to the initial movement of the pointer and thereafter the system following to the location of the pointer. 
     As indicated hereinabove, an electromechanical braking system or solenoid  106  (FIGS. 3,  4  and  9 ) is also provided. Solenoid  106  is operatively coupled between a power source  108 , switches  70 ,  72 , and motor  44 . The solenoid brake  106  is operatively coupled so that when current is not flowing through the solenoid, braking action is applied to motor  44 , as will now be evident to those having ordinary skill in the art, informed by the present disclosure. Such electromechanical braking systems are capable of withstanding great forces, depending on the solenoid chosen. This effect is desired to the extent that it would be anticipated that users of this apparatus will have a tendency to force workpieces against stops  24  in a repeated fashion, due to the nature of the work involved. Therefore, such a strong braking system is desired to prevent any creeping or dislocation of stops  24  and/or guide rail  22 . 
     The system described hereinabove is depicted schematically in FIG.  9 . In particular, as depicted in FIG. 9, a power source  108  is operatively coupled to switches  70  and  72 , which, when either is closed, will provide a current through the solenoid  106 . Again, as mentioned hereinabove, each switch  70  and  72  is oppositely wired or polarized so that current through one will cause motor  44  to engage linear actuator forwardly and current through the other, being of an opposite sort, will cause motor  44  to engage linear actuator  26  in the opposite direction or in retraction. Therefore, after current flows through a closed switch  70  or  72 , solenoid or brake  106  will receive that current and disengage its braking means and allow current to then flow and engage motor  44 . Thereafter, motor  44 , which is operatively coupled to linear actuator  26 , will cause linear actuator  26  to extend or retract depending on which type of current it receives from switch  70  or switch  72 . Of course, as described hereinabove, track switch left  70  or track switch right  72  are engaged or closed, thereby allowing current to flow therethrough by movement of knob  38  and pointer  36 , and therefore gantry  90  along rail  92  within housing  30 . As linear actuator  26  extends or retracts, likewise as depicted in FIG. 9, track rail  92  will also extend or retract until switch  70  or  72 , whichever is in a closed position, reaches rest area  88 , thereby causing both switches to again be in an open position. As described above, once those switches are both again in their rest or open position, current no longer flows through solenoid  106  and its electromechanical braking thereafter takes effect. 
     In use and operation, a user would by hand grasp knob  38  and move pointer  36  along scale  40  a desired distance to so move stops  24  that same desired distance and direction. As can now be understood, within seconds, stops  24  can be moved the entire length of scale  40 . Of course, longer guide rails can be provided for longer tables and shorter guide rails can be provided for shorter tables, but it is preferred that the guide rail be at least ten feet long as a standard industry practice. It is also preferred that the stops be spaced a foot apart, at least initially. Once the stops are set in the position that the user desires, a workpiece, or board, is abutted against the desired stop for the desired length to be cut. That is, if a four foot, six inch, cut is desired, the knob would have been moved six inches to the left, causing the stops to move six inches to the left, and the user would abut the workpiece against the fourth stop, assuming the first stop is one foot from the saw blade in a normal, initial position. By abutting the workpiece against the fourth stop, the first three stops pivot to a vertical position to thereby get out of the way of the workpiece. Thereafter, while the workpiece is now lying beneath the saw blade, the saw  12  is pivoted downward in cutting engagement with the workpiece, hence severing it to form a four foot, six inch length, or whatever other length might be desired. 
     Moreover, having thus described the invention, it should be apparent that numerous structural modifications and adaptations may be resorted to without departing from the scope and fair meaning of the instant invention as set forth hereinabove and as described hereinbelow by the claims.