Abstract:
A mortiser has a housing mounted on a support post and there is a collet on the housing for holding a mortise chisel. A chisel drive coupling is on the housing. A chisel drive shaft extends through the housing and connects with the chisel drive coupling. A reciprocal engagement mechanism is capable of selectively engaging the chisel drive coupling. An operating lever may thus be quickly indexed so that the mortise chisel may be filly lowered without the user pulling the operating lever fully toward him/her and downward. The mortiser also has a finely adjustable ram fence and a depth stop. The collet has a notched or elliptical bore to prevent jamming of the chisel shank in the collet.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims priority from U.S. Provisional Patent Application Serial No. 60/292,770, filed May 22, 2001, and entitled “Mortiser.” 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention is directed to machines capable of making a mortise cut into wood and, more particularly, to mortising machines.  
           [0004]    2. Brief Description of the Prior Art  
           [0005]    A mortise is a rectangular cavity cut into or through a piece of wood. Achieving this type of cut has been accomplished by various means. For example, round holes can be drilled into the wood, which are subsequently “squared off” through the use of a mortising chisel. On the other hand, a mortising knife and a mortising chisel can be used directly to form the rectangular cavity cut into the wood. This type of mortising can be very imprecise and labor intensive.  
           [0006]    In order to minimize the effort involved and improve the accuracy of cutting a mortise, mortising machines were developed. These were typically in two forms, adaptations of other pieces of woodworking equipment (drills, routers, etc.) and mortising machines that directly cut a mortise using a hollow square or rectangular mortise chisel. In most cases, the level of effort required to cut a mortise was improved, but the accuracy of the mortise was not.  
           [0007]    A common disadvantage of electric-powered chisel mortisers is that the action and heat generated from making the mortise cut causes the mortise chisel to become “stuck” in the chuck of the mortiser. In effect, the shank end of the mortise chisel becomes very difficult to remove from the chuck. A “stuck” mortise chisel creates obvious disadvantages regarding poor efficiency and inconvenience.  
           [0008]    Electric-powered chisel mortisers are limited as to the depth of the mortise cut that can be made. This limitation often occurs when an arm is used to lower the motor, chuck, and mortise chisel into a work piece. The arm can only be moved by pulling the arm from an upper position to a lower position. Once the lower position is reached, the mortise chisel can be lowered no further, and a finite depth of a mortise cut is reached. Also, it may be awkward for the user to fully pull the lever toward him to achieve the desired deep mortise cut.  
           [0009]    There is a need for an electric-powered mortiser in which mortise chisels do not become “stuck.” It is also desirable to expand the depth of mortise cuts that can be achieved using an electric-powered mortiser. Finally, it is desired to facilitate fine adjustments of the position of a work piece on a table of the mortiser, using an adjustable fence.  
         SUMMARY OF THE INVENTION  
         [0010]    The present invention has several aspects generally related to abrading machinery which is configured to vertically engage and disengage a cutting tool with a work piece. First, the invention is directed to a mortiser for making a mortise cut in a work piece. The mortiser having a base, a table mounted on the base, a housing supported above the base, and a collet connected with the housing for receiving a mortise chisel shank. The mortiser includes a motor, with a chisel drive shaft extending through the housing and a chisel drive coupling attached to the chisel drive shaft. A collet lowering mechanism is connected with the chisel drive shaft, and a reciprocal engagement mechanism is capable of selectively engaging the chisel drive coupling. An operating lever is attached to the reciprocal engagement mechanism for rotating the chisel drive shaft and for reciprocating the reciprocal engagement mechanism into and out of engagement with the chisel drive coupling. When the coupling and reciprocal engagement mechanism are engaged, and an operator pulls the lever, the chisel drive shaft and the collet lowering mechanism cooperate to lower the collet toward the work piece.  
           [0011]    The invention also includes a method of abrading a work piece using a motorized machine which is configured to vertically engage and disengage a cutting tool with the work piece. The method comprises the steps of positioning the work piece below the cutting tool and engaging an operating lever with a drive coupling on the machine, the drive coupling mechanically interconnected with the cutting tool so as to permit upward and downward movement of the cutting tool. The cutting tool is then lowered a first increment toward the work piece by pulling the lever from a first position to a second position. Later, the lever is disengaged from the drive coupling and repositioned to the first position. The lever is then reengaged with the drive coupling, and the user then further lowers the cutting tool a second increment by again pulling the lever from the first position to the second position.  
           [0012]    The invention is also directed to a mortiser for making a mortise cut in a work piece. The mortiser having a base, a table mounted on the base and a housing supported above the base. A collet extends downward from the housing for receiving a mortise chisel shank, and the mortiser has a motor. A mechanism for raising and lowering the collet is provided, and according to this aspect of the invention, the collet has a chisel shank removal device in an interior bore of the collet to facilitate removal of the chisel shank from the collet. The chisel shank removal device may be a notch extending the length of the internal bore in the collet or it may comprise the internal bore of the collet having an elliptical shape.  
           [0013]    Next, the invention comprises a machine for abrading a work piece. The machine having a base, a motor, a table mounted on the base, a housing supported above the base and a mechanism for holding a cutting tool extending downward from the housing. According to this aspect of the invention, the machine for abrading a work piece has an adjustable fence positioned on an upper surface of the table, with at least one fence ram assembly connected with the adjustable fence. The fence ram assembly comprises at least one positive stop slidably attached to a cylindrical ram. The assembly also includes a post having an internal bore, a set screw hole, and a set screw with a set screw handle. The cylindrical fence ram is journaled in the bore of the post and attached to the rear side of the adjustable fence. Preferably, the machine has two fence ram assemblies behind the adjustable fence.  
           [0014]    These and other advantages can be found in the present invention and will be clarified in the description of the preferred embodiment taken together with the attached drawings in which like reference numerals represent like elements throughout. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 is a front perspective view of the mortiser of the present invention;  
         [0016]    [0016]FIG. 2 is a rear perspective view of the mortiser of the present invention particularly showing the microadjustable fence of the present invention;  
         [0017]    [0017]FIG. 3 is a front elevational view of the mortiser of the present invention;  
         [0018]    [0018]FIG. 4 is a right side elevational view of the mortiser of the present invention;  
         [0019]    [0019]FIG. 5 is a schematic view of an engaged reciprocal engagement mechanism and chisel drive coupling according to the present invention;  
         [0020]    [0020]FIG. 6 is a schematic view of the reciprocal engagement mechanism and chisel drive coupling of FIG. 5, but shown in a disengaged position;  
         [0021]    [0021]FIG. 7 is a schematic view of a collet lowering mechanism of the present invention;  
         [0022]    [0022]FIG. 8 is a cross section view of one collet according to the present invention;  
         [0023]    [0023]FIG. 9 is a top view of the collet shown in FIG. 8;  
         [0024]    [0024]FIG. 10 is a top view of another collet according to the invention; and  
         [0025]    [0025]FIG. 11 is a bottom view of the mortiser of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]    For the purpose of the description hereinafter, the terms “upper,” “lower,” “right,” “left,” “vertical,” “horizontal,” “top,” “bottom,” and derivatives thereof shall relate to the invention as oriented in the drawing Figures. However, it is to be understood that the invention may assume alternate variations and step sequences except where expressly specified to the contrary. It is also to be understood that the specific devices and methods, illustrated in the attached drawings and described in the following specification, are exemplary embodiments of the invention. Hence, specific dimensions and other physical characteristics related to the embodiment disclosed herein are not to be considered as limiting the invention.  
         [0027]    In FIG. 1, a mortiser  10  has a motor  14 , a housing  36 , a reciprocal engagement mechanism  30 , an operating lever  12 , a notched post  46 , a spring-loaded post  40 , a table  18 , a fence  22 , and a base  38 . Motor  14  utilizes electric power, which is supplied via transformer  44  in order to provide the required direct current and voltage for motor  14 . Motor  14  includes a drive shaft (not shown) to which a chuck in the housing (also not shown) is attached. Collet  16  is adapted to receive a mortise chisel  17 , and the chisel is fixed in place via a set screw (not shown) fixed via set screw hole  54  (FIG. 4). Particularly, set screw  54  engages a rim that extends downward from housing  36 . Table  18  rests on top of base  38  and is moved in a left or right direction by a rack and pinion mechanism  21 , which includes a table pinion  19  and a table rack  123  (as shown in FIG. 11). Table pinion  19  is in contact with and engaged with table rack  123 . The rack and pinion mechanism  21  is driven by rack and pinion wheel  20 , which communicates with the rack and pinion mechanism  21  by table adjust screw  58  (shown in FIG. 4). The mortiser  10  may be sized and designed to be used on a bench top or to be joined with a stand for floor installation.  
         [0028]    Operating lever  12  has a handle end  90 , onto which is placed a handle  34 , a lever portion  88 , and a drive end  92 . Referring to FIG. 5, a lever insert  122  has a threaded portion  86  (covered by a nut  60  in FIG. 5), a pivot point  84 , an insert end  126 , and a terminal end  124 . Insert end  126  is inserted into a hollow portion  91  of drive end  92  of operating lever  12 . The threaded portion  86  begins at terminal end  124  and extends a distance along lever insert  122  sufficient to threadably attach nut  60 . A portion of lever insert  122  passes through reciprocal engagement mechanism  30 . A locking pin (not shown) may be placed through a locking pin channel  82  in lever insert  122 . Reciprocal engagement mechanism  30  includes a body  70  engaged and in contact with a right chisel drive coupling  72  or a left chisel drive left coupling  74 , a piston  114  located within body  70  and having a head  118  that abuts pivot point  84  on lever insert  122 , a spring housing  77 , and a spring  78  inside spring housing  77  covering a portion of piston  114 . Spring  78  exerts pressure on piston head  118 . Body  70  is thus biased into engagement with right coupling  72 .  
         [0029]    Returning to FIG. 1, housing  36  has a top side  100 , a right side  96 , a left side  104 , a front side  94 , a rear side  98 , and a bottom side  102 . Attached to rear side  98  of housing  36  is an accessory holder  64  (see FIG. 2).  
         [0030]    Housing  36  (and collet  16 ) is moved vertically by the action of operating lever  12  and reciprocal engagement mechanism  30 . FIG. 3 shows body  70  engaged with right coupling  72 . FIGS. 5 and 6 show that body  70  has a grip end  108 , and right coupling  72  has a grip end  106 . Grip ends  106 ,  108  are constructed such that they can selectively interlock with a ratchet action (for example, by providing intermeshing teeth  109 ). The raised portions along grip end  106  fit within the recessed portions of grip end  108 , and the raised portions along grip end  108  fit within the recessed portions of grip end  106 . FIG. 3 shows a tooth grip  76  established between right coupling  72  and body  70 .  
         [0031]    Referring to FIGS. 5 and 6, body  70  engages right coupling  72  (shown) or left coupling  74  (shown in FIG. 3). Reciprocal engagement mechanism  30  can thus be in an engaged position  110  or a disengaged position  112 .  
         [0032]    Focusing on FIG. 5, reciprocal engagement mechanism  30  is in engaged position  110 , which means that the raised portions along grip end  106  are intermeshed within the recessed portions of grip end  108 , and the raised portions along grip end  108  are intermeshed within the recessed portions of grip end  106 . Lever insert  122  passes through a channel  116  in body  70 . Piston head  118  is held firmly and squarely against lever insert  122 , directly opposite of pivot point  84  by spring  78 . Piston  114  has a drive end  120  received in right coupling  72 . Drive end  120  is inserted into a threaded piston channel  150  located within right coupling  72 . A set screw (not shown) is threadably inserted into set hole  148  to secure right coupling  72  in place on drive shaft  80 . A first washer  68 , through which lever insert  122  passes, rests firmly against body  70  and is held in place by a lever spring  32 . Lever spring  32  provides tension against first washer  68  and a second washer  66 , through which lever insert  122  also passes. The pressure applied by lever spring  32  against second washer  66  holds it firmly against nut  60  and biases lever  12  in the upright position.  
         [0033]    Mortiser  10  may be reconfigured for left-handed operation. This is accomplished by removing threaded piston  114  and body  70  from right coupling  72  and attaching it to left coupling  74 . Body  70  is removed from right coupling  72  by loosening nut  60 , withdrawing lever insert  122  and lever  12  from channel  116 , and then unscrewing piston  114  via head  118 . Body  70  is then attached to left coupling  74  by inserting drive end  120  of piston  114  into piston channel  150  of left coupling  74  and screwing in piston  114  to tighten. Lever insert  122  and lever  12  are then remounted in channel  116 . When attached to left coupling  74 , body  70  is operated as described with respect to right coupling  72 , except the operator may then use his left hand.  
         [0034]    When the reciprocal engagement mechanism  30  is in the engaged position  110 , housing  36  can be lowered, for example, by an operator grasping handle  34  and pulling it in a generally forward and downward direction. This action through operating lever  12  and lever insert  122  causes body  70 , coupling  72 , and chisel drive shaft  80  to rotate counter-clockwise. Particularly, operating lever  12  is pulled from its substantially upright position (shown in FIG. 4) toward table  18  a first increment, so that lever  12  ends up in a more inclined position.  
         [0035]    Turning to FIG. 7, a collet lowering mechanism  128  is located inside of housing  36  and includes notched post  46 , chisel drive shaft  80 , and a pinion  130 , which is mounted on chisel drive shaft  80 . When operating lever  12  is pulled, pinion  130  is rotated (by shaft  80 ) and moved along notched post  46 . Pinion  130  has a plurality of extended portions  131  such that extended portions  131  engage the recessed portions of notched post  46 . The interaction of pinion  130  and notched post  46  causes housing  36  to move downward, thereby feeding collet  16  and mortise chisel  17  (shown on FIG. 1) to a work piece. Pushing lever  12  causes the housing to move upward along post  46 . Spring-loaded post  40  biases the housing (or “head”)  36  upward.  
         [0036]    If operating lever  12  has been rotated to a point that it can be rotated no further, yet the mortise chisel has not reached the desired depth into the work piece, lever  12  can be reset to the substantially upright “top position” shown in FIGS.  1 - 4 . This is accomplished by first securing the housing  36  using upper stop screw  51 . Then, operating lever  12  and reciprocal engagement mechanism  30  are placed in the disengaged position  112  (i.e., by operating lever  12  outward as shown in FIG. 6). Lever  12  is then rotated in a generally upward direction to the “top position.” Operating lever  12  is then repivoted to the engaged position  110  (i.e., by pivoting inward as shown in FIG. 5). After the body  70  and coupling  72  are reengaged, stop screw  51  is loosened and handle  34  is again pulled in a generally forward and downward direction to further lower the collet  16  and chisel  17 .  
         [0037]    In disengaged position  112  (FIG. 6), operating lever  12  is moved such that handle  34  is moved in a direction generally away from motor  14 , which moves terminal end  124  of lever insert  122  in a direction generally toward housing  36 . This action causes operating lever  12  and lever insert  122  to deflect about pivot point  84 . In this position, spring  78  is compressed along piston  114  and lever insert  122  pushes against channel  116  moving body  70  away from right coupling  72 . When enough movement is accomplished, tooth grip  76  is disengaged, and space  132  is formed between body  70  and right coupling  72 .  
         [0038]    Referring to FIGS. 8 and 9, collet  16  has a chisel shank channel  136 , a wall  134 , a threaded chisel set hole  56 , threaded set screw hole  54 , a bottom side  142 , and a lip  140 . Chisel shank channel  136  is substantially round or elliptical in shape and preferably has a notch  138  that preferably extends the length of chisel shank channel  136 . The notch  138  and/or elliptical shape of chisel shank channel  136  help to prevent a mortise chisel  17  from becoming “frozen” or “stuck” in collet  16  during and after use. Chisel set hole  56  is preferably aligned with notch  138 . Lip  140  provides a surface to seat collet  16  to a rim on the housing  36  when a set screw is threadably inserted into set screw hole  54 . FIG. 10 shows another collet  16 ′ for use with smaller chisel shanks. Collet  16 ′ has two bores of different centers drilled therein, thus producing an “elliptical-shaped” bore  136 ′.  
         [0039]    To load the mortise chisel  17  into collet  16 , the non-cutting (or shank) end of the chisel is inserted into chisel shank channel  136  such that, at a minimum, the top of the chisel is inserted beyond chisel set hole  56 . Once the chisel has been completely inserted, a set screw (not shown) is inserted into chisel set hole  56  such that it presses tightly against the chisel shank.  
         [0040]    The depth of a mortise cut is controlled by how deep mortise chisel  17  penetrates into a work piece. It is desirable to be able to consistently make multiple mortise cuts of the same depth. In order to facilitate multiple, equal-depth mortise cuts, depth stop  48  is used. As shown in FIGS.  1 - 4 , depth stop  48  is cylindrical and fits snugly around notched post  46 . Depth stop  48  has a depth screw  50 , which is attached to depth stop  48 . The desired location of depth stop  48  is attained by moving it along the length of notched post  46 . Once in the desired location, depth stop  48  is secured in place by tightening depth screw  50  such that it rests tightly against notched post  46 . Once in place, housing  36  is only able to descend until it makes contact with depth stop  48 .  
         [0041]    Prior to operating mortiser  10 , a piece of wood, or work piece, is placed on table  18 . The work piece is prevented from moving by placing it firmly against fence  22 . Comers of the work piece may be held securely against table  18  through the use of conventional clamps. Once a work piece is securely in place, it can be moved from right to left (when the user is facing rack and pinion wheel  20 ) by turning rack and pinion wheel  20 .  
         [0042]    According to the invention, fence  22  may be an adjustable ram fence assembly that includes a block  144  having a threaded internal bore attached to the upper surface of base  38  (see FIG. 2), a fence adjust screw  52  having a fence end and a wheel end, the fence end in fixed contact with an equipment side of fence  22  and threadably connected to and passing through the threaded internal bore of block  144 , and at least one ram assembly that includes two positive stops  23 ,  23 ′. A post  62  has an internal bore (not shown), a set screw hole (not shown), and a set screw with set screw handle  28 . A cylindrical fence ram  26  is passed through the bore of post  62  and is attached to a collar  24  on fence  22 .  
         [0043]    In order that successive work pieces can be cut identically, fence  22  can be adjusted to accommodate a variety of depths along table  18 . Fence  22  is moved by turning ram fence wheel  42 . Fence adjust screw  52  extends from ram fence wheel  42  to fence  22 . Fence adjust screw  52  is held in place by block  144  having a threaded, internal bore. When ram fence wheel  42  is turned, it causes fence adjust screw  52  to rotate and either push forward or pull rearward the fence  22 .  
         [0044]    Once fence  22  has been moved into position, it is firmly braced in place by fence rams  26 . Set screw handle  28  on post  62  is tightened onto fence ram  26 . This action holds fence ram  26  in place and, in turn, holds fence  22  in place. There can be one or more fence rams  26  to hold fence  22  in place. Preferably, there are two fence rams  26  as shown in the drawings.  
         [0045]    In order to limit the forward position of fence  22 , positive stops  23 ′ are positioned along rams  26  such that they are in contact with post  62  when the desired forward position of fence  22  is achieved. A stop set screw  27  is then tightened to secure the location of positive stop  23 ′ along ram  26 . Once set screw  27  is tightened, ram fence wheel  42  will not be able to be turned to move fence  22  in the general direction of rack and pinion wheel  20 , thus defining a set forward position of fence  22 . Ram fence wheel  42  may, however, be turned to move fence  22  away from rack and pinion wheel  20 . When the set forward position of fence  22  is desired, ram fence wheel  42  is turned until positive stops  23 ′ contact post  62 . Likewise, stops  23  may be positioned to limit the rearward movement of fence  22 .  
         [0046]    The invention has been described with reference to the preferred embodiments. Obvious modifications and alterations will occur to others upon reading and understanding the preceding detailed description. For example, the mortiser may be provided with a right chisel coupling only, a left chisel coupling only, or (as shown) both. The various inventions herein may also be readily adapted to drill presses or the like. The present invention has been described with reference to specific details of particular embodiments thereof. It is not intended that such details be regarded as limitations upon the scope of the invention except insofar as and to the extent that they are included in the accompanying claims.