Hand tool for forming a pocket mortise and method

A hand tool useful in forming a pocket mortise in the surface of a workpiece proximate an edge of the workpiece. The hand tool includes a clamping assembly for releasably clamping the tool to the workpiece, and a router carried by the clamp assembly and mounted for manual displacement toward the workpiece edge at an incline to progressively cut deeper into the workpiece and form an inclined pocket mortise. The hand tool also preferably carries a drill bit guide on the clamp assembly which is formed to receive and guide a drill bit from a hand drill for drilling a bore from the workpiece edge to the mortise. A method of forming a pocket mortise including the steps of clamping the clamp assembly with a movable router to a workpiece, routing the pocket mortise and then drilling a hole to the pocket mortise from the edge of the workpiece by a hand drill also is described.

TECHNICAL FIELD 
The present invention relates, in general, to an apparatus and method for 
joining together two workpieces of the type often used in furniture, 
cabinetry or case work, and more particularly, relates to an apparatus and 
method for forming a pocket mortise in the surface of a workpiece so that 
the workpiece can be joined, for example, by a screw, to a second member. 
BACKGROUND ART 
There are many applications in furniture, cabinetry and case work joinery 
in which a pocket mortise is employed to form a joint between two 
workpieces. Thus, in ready-to-assemble or knock-down furniture and in 
connection with joining together the elements of cabinets, cases, counters 
and the like, pocket mortises are employed to provide a high-strength 
joint which often can be hidden to provide desirable cosmetic effects. 
When furniture or case work is being manufactured in volume, it is feasible 
and quite advantageous for pocket mortises to be formed using a production 
or shop tool of the type described in my prior U.S. Pat. No. 4,603,719. 
The mortise pocket forming tool of my patent is readily adaptable (for 
example, by employing multiple heads) for use by manufacturers and/or job 
shops to produce pocket mortises of high-quality at relatively low cost. 
The pocket mortise forming apparatus of my patent, however, is somewhat 
specialized for the average carpenter, woodworker or do-it-yourself 
handyman to have available in their shop for the formation of only a few 
mortises in a few pieces of furniture or cabinetry. Thus, a carpenter or 
do-it-yourself woodworker is not likely to have a shop which would be 
sufficiently complete to have a pocket mortise forming apparatus as set 
forth in my U.S. Pat. No. 4,603,719. Moreover, even if such an apparatus 
is in the shop of a carpenter, it will not be readily available for 
on-site use when small projects are involved. 
Nevertheless, pocket mortises are highly advantageous structures that can 
be utilized with a variety of mortise inserts, as for example are set 
forth in my U.S. Pat. No. 4,944,627, to produce joints between structural 
members that have many desirable qualities. Thus, while pocket mortise 
joints are used in manufactured or production structures the lack of a 
practical hand tool or in-the-field way of precisely forming pocket 
mortises has limited their use by woodworkers in non-production settings. 
Accordingly, it is an object of the present invention to provide a hand 
tool which can be easily transported and used by a carpenter or woodworker 
to form high-quality, well-indexed pocket mortises for use in woodworking 
joinery applications. 
Another object of the present invention is to provide a pocket mortise 
forming hand tool and method which is suitable for use by relatively 
unskilled woodworkers to form a high-quality, screw mortise joint. 
Still another object of the present invention is to provide a hand tool for 
forming a pocket mortise in a workpiece which is highly portable, 
relatively inexpensive to manufacture and is easy to use. 
Still a further object of the present invention is to provide a hand tool 
for formation of a pocket mortise which allows the woodworker to take 
advantage of a commonly owned woodworking hand tool, namely, the hand 
drill to thereby eliminate the need for integration of a drill into the 
hand tool. 
Still a further object of the present invention is to provide a hand tool 
and method for forming a pocket mortise in a workpiece which requires 
minimal time to use, involves a minimum number of components, and produces 
a joint which is high in strength. 
The pocket mortise forming hand tool and method of the present invention 
have other objects and features of advantage which will be apparent from 
the accompanying drawing and from the following description of the Best 
Mode Of Carrying Out The Invention. 
SUMMARY OF THE INVENTION 
The hand tool of the present invention is suitable for use in forming a 
pocket mortise in the surface of a workpiece proximate an edge of the 
workpiece. The hand tool comprises, briefly, a clamp assembly formed for 
releasable clamping of the tool to the workpiece proximate the edge of the 
workpiece and a, router carried by the clamp assembly and having a router 
bit with an axis rotation oriented transverse to the surface in which the 
mortise is to be formed. The router is mounted on the clamp assembly for 
displacement in a direction transverse to and toward and away from the 
edge and for displacement of the cutting bit on an incline to cut 
progressively deeper into the workpiece. The hand tool further preferably 
includes a drill bit guide mounted to the clamp assembly and formed to 
receive and guide the drill bit of a hand drill for drilling of a bore 
from the edge of the workpiece to the pocket mortise formed by the router. 
In the preferred form, the router is mounted on a carriage slidably 
mounted to the clamp assembly for movement along an inclined path, and the 
drill guide is provided as a bushing mounted on the clamp assembly in 
indexed relation to the mortise-forming router. 
The method of forming a pocket mortise of the present invention is 
comprised, briefly, of the steps of clamping a clamp assembly having a 
movable router mounted to the clamp assembly proximate the edge of a 
workpiece with the router bit oriented transverse to an upper surface of 
the workpiece, routing an inclined pocket mortise in the workpiece by 
manually displacing the router along a progressively inclined path toward 
an edge of the workpiece, and drilling a hole from the edge of the 
workpiece to the pocket mortise using a hand drill. The drilling step 
preferably is accomplished by drilling through a drill guide carried by 
the clamp assembly while the clamp assembly is still clamped to the 
workpiece.

BEST MODE OF CARRYING OUT THE INVENTION 
In my U.S. Pat. Nos. 4,944,627 and 4,603,719 highly useful pocket mortises 
and fastener assemblies for mounting in such mortises are described in 
detail and will not be repeated herein. The pocket mortise formed by the 
present hand tool is not regarded as a novel portion of the present 
invention. As noted above, my U.S. Pat. No. 4,603,719 discloses a shop or 
production tool which is highly useful in forming such pocket mortises. 
The present invention, however, is directed to a hand-held tool which has 
high portability and yet can easily and rapidly be employed to form a 
pocket mortise of comparable precision and quality to that formed by more 
elaborate shop and production tools. 
As best may be seen in FIG. 1, the hand tool of the present invention, 
generally designated 21, is designed to form a pocket mortise 22 in the 
top surface 23 of a workpiece 24. Mortise 22 is formed proximate an edge 
26 of the workpiece, and more particularly proximate the edge which is to 
be joined to another member, as described in detail in U.S. Pat. Nos. 
4,944,627 and 4,603,719. 
Hand tool 21 preferably includes three components, namely, a clamp 
assembly, generally designated 27, a router assembly, generally designated 
28, and drill bit guide means, generally designated 29. As used herein, 
however, the expression "router assembly" shall be understood to include 
essentially the elements above clamp portion or plate 37, such as router 
30, carriage 52 and track means 53. Moreover, in the broadest form of the 
invention drill bit guide means 29 need not be present. 
In most applications, workpiece 24 will be a board, a piece of frame stock 
or sheet-like member, but it will be understood that in the broadest 
aspect of the present invention, clamp means 27 can be formed to clamp 
hand tool 21 to workpieces of various sizes and descriptions. The purpose 
of clamp assembly 27 is to secure the hand tool to the workpiece so that 
pocket mortise 22, cut by router 30, and fastener receiving bore 31, 
produced by hand drill 32, communicate with each other or are in 
relatively indexed relation to form the pocket mortise. 
One form of clamp assembly 27 suitable for use in securing the overall hand 
tool in a fixed relation to the workpiece is a clamp assembly having a 
generally U-shaped frame, here oriented on its side, with two horizontally 
oriented clamping portions and a vertically oriented connecting frame 
portion. Thus, two vertical, side-by-side, frame connecting portions 36a 
and 36b, which are joined together by central portion 35, have an upper 
horizontal clamping portion 37, formed to engage a substantial area of 
surface 23 of the workpiece fixedly mounted to an upper end of connecting 
frame portions 36a and 36b. Mounted in spaced relation to upper portion 37 
and movable with respect thereto, is a lower clamping portion or member 
38. Lower clamping portion 38 can be provided as a wooden member which is 
mounted by fasteners 41 to socket 42, formed to rotatably receive threaded 
shaft 43. Extending outwardly from frame portions 36a and 36b is a 
threaded sleeve 44, which threadably receives shaft 43. Inner ends 46 
(FIG. 2) of lower work engaging member 38 slidably engages the frame 
portions 36a and 36b as member 38 is displaced axially by rotation of 
manually engageable handle 47. 
Clamping assembly 27 also can include an edge engaging member 40 mounted to 
clamp connecting portions 36a and 36b so as to provide a surface for 
engagement of the workpiece edge 26 and preferably a low-friction surface 
for sliding engagement by the inner end 45 of the notch of lower clamping 
member 38. 
The details of construction of clamp assembly 27 are broadly known in the 
clamping art and do not, by themselves, constitute a novel portion of the 
present invention. 
In order to form precisely dimensioned pocket mortise 22, hand tool 21, as 
is the case for the shop tool of my U.S. Pat. No. 4,603,719, includes a 
router assembly 28 having a router 30 which is mounted with router bit 51 
having an axis of rotation oriented transverse to surface 23. As will be 
seen from FIG. 1, bit 51 is nearly perpendicular to surface 23, but it 
also can be seen to be inclined at a slight angle so as to progressively 
cut more deeply into surface 23 as the router is advanced in the direction 
of arrow 50 in FIG. 5. The advantages of orientation of router bit 51 are 
described in more detail in my U.S. Pat. No. 4,603,719, and those 
advantages are present in the hand tool of the present invention. 
Router 30 is movably mounted for manual displacement by the user along an 
inclined path (for example, about 12 degrees). This can most easily be 
provided by mounting router 30 on a carriage 52 which is slidably mounted 
to a router guide track, generally designated 53, carried by or mounted to 
clamp assembly 27. Track 53, as best may be seen in FIG. 3, can be 
provided by a pair of inwardly turned flanges 54 on upwardly extending 
side walls 56 of the clamp assembly upper clamping portion or plate 37. 
Carriage 52 can be provided by a transversely extending plate having 
upturned sides 58. The carriage is held up against track 54 by a 
transversely extending lower plate 59 beneath carriage plate 52 and a 
transversely extending upper plate 61 having ears (FIGS. 3 and 4) 62 which 
engage the top surface of flanges 54. 
In order to provide additional versatility, router is removably mounted to 
carriage plate 52 by fasteners 64, and fasteners 66 clamp upper track 
engaging guide plate 61 to carriage plate 52. The carriage and guide track 
assembly, shown and described, is particularly well suited for use with 
the present invention in that it is relatively inexpensive to construct 
and yet is durable and permits removal of the router from the hand tool 
for cleaning, repair and maintenance. Router 28 can be a hand router of 
the type conventionally available on the market, for example, a hand 
router of the type made by Porter-Cable Corporation, Jackson, Tenn. It 
will be understood, however, that the particular carriage and track 
assembly for movable mounting of the router to the clamp assembly can be 
varied within the scope of the present invention. If desired, carriages 
supported by wheel assemblies or ball bearings can be employed in the hand 
tool of the present invention, although they tend to increase the overall 
cost of manufacturing the hand tool somewhat. Additionally, spring biasing 
means, not shown, can be employed to bias the router and carriage to the 
position of FIG. 5 for safety and convenience so that fit 51 does not 
protrude below plate 37. 
As will be apparent from FIG. 1, both carriage plate 52 and clamping plate 
37 must have openings therein to receive router bit 51 therethrough. Thus, 
a bore 67 is provided in carriage plate 52 and an elongated slot 68 is 
provided in clamping plate 37. 
It is an important feature of the present invention that router 30 be 
mounted to carriage 52 in a manner permitting adjustment of the depth to 
which bit 51 cuts mortise 22. In the hand tool of FIG. 1, router 30 is 
mounted in a sleeve 65 fixedly mounted to router base 63. Sleeve 65 is 
clamped by fastener 70 around the body of the router. Thus, fastener 70 
can be loosened to permit adjustment of the depth of router bit relative 
to sleeve 65 and base 63. Once the desired depth is reached, fastener 70 
is tightened to clamp the router in a fixed position. 
In order to limit the advance of router bit 51 toward edge 26 so that the 
pocket mortise will have a shoulder 69 in predetermined spaced relation to 
edge 26, hand tool 21 preferably includes adjustable stop means 71 which 
engages carriage plate 52 and limits the forward displacement of the 
router bit. Nut 72 allows the user to adjust stop means 71 and thereby 
adjust the location of shoulder 69 relative to edge 26. Stop 71 is secured 
to transversely extending end channel 73, in this case by welding, to 
upper clamping plate 37, but most preferably by die casting. 
In order to reduce the size and complexity of the hand tool of the present 
invention, it is constructed in a manner which enables it to be used with 
another hand tool commonly owned by most carpenters and do-it-yourself 
craftsmen, namely, a hand drill. Thus, hand tool 21 is designed for use 
with a hand drill 32, rather than attempting to integrate into the hand 
tool a drill assembly, as is the case with the shop or production tool of 
U.S. Pat. No. 4,603,719. Hand tool 21 includes a drill bit guide assembly 
29 mounted to clamp assembly 27 in a manner so as to ensure that bore 31 
will extend from edge 26 of the workpiece to pocket mortise 22 formed by 
router 30. 
In the preferred form, a guide bushing 81 is secured to a mounting flange 
82 and is formed with a central opening 83 dimensioned to receive a hand 
drill bit 84 (FIGS. 1 and 6). Since mortise shoulder 69 is at a slight 
angle (about 12 degrees) to the vertical, it is preferably that the 
mounting flange 82 for guide 81 be at about one-half the mortise angle 
(most preferably about 6 degrees). This will orient guide hole 84 in a 
manner producing a bore 31 that will enter mortise 22 in a close to 
perpendicular orientation to mortise shoulder 69 and will flatten out the 
orientation of the fastening screw so that it will pull better across the 
joint. Thus, the bore 31 will be seen to slope downwardly only slightly 
from shoulder 69 to edge 26. 
In the preferred form of the hand tool of the present invention, the 
mounting flange 82 is adjustably mounted to frame member 36 by fastener 86 
which passes through an elongated slot 85 (FIG. 2) in the mounting flange 
82. By adjusting flange 82, the location of bore 31 to mortise 22 can be 
adjusted so as to provide sufficient room for the head of the screw or 
other fastener which is passed through bore 31 during formation of the 
mortise joint. 
While it is preferable to use drill guide bushing 81 to guide drill bit 84, 
it will be understood that it also would be possible to remove hand tool 
21 from workpiece 24 after forming mortise 22 and drill bore 31 without 
guiding the same using the hand tool. The advantage of leaving the tool 
damped on the workpiece and using drill guide 81 is that bore 31 will be 
more precisely controlled and indexed relative to the mortise. 
The pocket mortise forming method of the present invention and operation of 
the hand tool can now be described. Hand tool 21 is first clamped to edge 
26 of workpiece 24 with edge 26 in engagement with clamp bearing surface 
member 40. The user cinches down on handle 47 to clamp the workpiece 
between movable lower clamp member 38 and upper stationary clamp plate 37. 
At the outset, the router is in the position shown in FIG. 5 and is not 
powered. The router can then be turned on by switch 90 (FIG. 2) and the 
user will manually engage the router body and advance the router toward 
edge 26, as indicated by arrow 50 in FIG. 5, until carriage plate 52 hits 
stop 71. This is the router position shown in FIGS. 2 and 6. At this point 
in the method, a sloping pocket mortise 22 will have been formed in upper 
surface 23 of the workpiece. The router is then returned manually, as 
indicated by arrow 95 in FIG. 6, to the position of FIG. 5 and the router 
turned off. 
While clamp assembly 27 is still clamped to workpiece 24, hand drill 32 is 
used to drill bore 31 by inserting the drill bit 84 into the opening 83 in 
guide bushing 81, as indicated by arrow 96 in FIG. 6, and drilling until 
bit 84 reaches pocket mortise 22. The drill then can be removed from the 
guide bushing and the hand tool unclamped from the workpiece. The result 
will be a pocket mortise in surface 23 of the workpiece proximate edge 26 
that can be used to form a high-strength joint between the workpiece and 
another structural member. 
It will be understood, that since the clamp assembly holds the relative 
positions at which the router and drills will cut in fixed, indexed 
relation, it will be possible to perform the drilling step before the 
routing step. In that case, the drill has to be advanced to a position 
sufficiently deep into the edge 26 so as to ensure that the bore will 
communicate with the subsequently formed mortise 22. 
As will be apparent from the above, a hand tool constructed as above 
described is relatively inexpensive to manufacture, and accordingly, 
feasible for the average handyman or carpenter to own. The hand tool 
provides a rapid and easily learned method for producing a pocket mortise 
that can advantageously be used in numerous carpentry applications. 
Moreover, the portability of the hand tool allows it to be clamped easily 
to a workbench by a separate clamp or fixture (not shown) for low-volume 
production runs. 
The frame for the clamp assembly and guide track for the router preferably 
are die cast from steel, but the workpiece engaging surfaces also can all 
be formed of a wood, formica or other materials. Router 30 also can be 
removed easily from the hand tool of the present invention for other, more 
conventional, routing applications. The hand tool of the present 
invention, therefore, can be employed for multiple purposes, including 
general purpose routing and the formation of pocket mortises.