U.S. patent number 3,893,238 [Application Number 05/412,188] was granted by the patent office on 1975-07-08 for butt seam cutting tool.
Invention is credited to Albert S. Scholl.
United States Patent |
3,893,238 |
Scholl |
July 8, 1975 |
Butt seam cutting tool
Abstract
A hand operated tool for cutting relatively heavy paper and
plasticized wall coverings, cork, carpet and like materials. A
cutting blade is held by a manually engageable holder in bi-angular
relation to the plane of the material to be cut. As the tool
advances along a desired cutting line, the material is severed in a
plane disposed in acute angular relationship to the plane of the
material. The effect of this provides an undercut edge on the
material whereby such edge may be arranged in overlapping
relationship with a matingly angulated edge of adjacent material to
produce a seamless butt joint. The blade cooperates with an
underlying guide shoe and material guiding means in making the
angulated cut. Inversion of the tool presents a second knife edge
for cutting the material at matching angles in those instances
where the guide shoe cannot be employed.
Inventors: |
Scholl; Albert S. (Chicago,
IL) |
Family
ID: |
23631957 |
Appl.
No.: |
05/412,188 |
Filed: |
November 2, 1973 |
Current U.S.
Class: |
30/294; 30/287;
30/289 |
Current CPC
Class: |
B26B
5/005 (20130101); A47G 27/0487 (20130101); B44C
7/08 (20130101) |
Current International
Class: |
A47G
27/00 (20060101); B44C 7/00 (20060101); A47G
27/04 (20060101); B44C 7/08 (20060101); B26B
5/00 (20060101); B26B 003/08 (); B26B 029/02 () |
Field of
Search: |
;30/294,293,289,291,286,287,290 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
566,233 |
|
Dec 1944 |
|
GB |
|
50,952 |
|
Apr 1910 |
|
CH |
|
1,343,561 |
|
Oct 1963 |
|
FR |
|
146,889 |
|
Apr 1936 |
|
OE |
|
Primary Examiner: Smith; Al Lawrence
Assistant Examiner: Zatarga; J. T.
Attorney, Agent or Firm: McCaleb, Lucas and Brugman
Claims
I claim:
1. A hand operated tool for cutting angulated butt seam edges in
wall covering materials and the like comprising: an elongated
planar guide shoe formed with an opening therethrough and having a
bottom planar guide surface engageable with an underlying wall to
guide the tool in its normal operating position, a generally planar
body member affixed to said guide shoe adjacent one end thereof
such that the plane of said body member lies in acute angular
relation to the plane of said guide shoe and guide surface, an
elongated arm portion formed on said body member in overhanging
spaced alignment with the longitudinal axis of said guide shoe and
opening such that the longitudinal axis of said arm portion
intersects the plane of said guide shoe and guide surface; holder
means affixed to said arm portion and comprising a pair of parallel
spaced wall portions for slidably receiving and holding a cutting
blade in the plane of said body member, a cutting blade
frictionally mounted in said holder means and having a first
cutting edge in the plane of said body member and parallel to the
longitudinal axis of said arm portion to subtend in bi-angular
intersecting relationship with the plane of said guide surface,
said cutting edge invading said opening rearwardly of the leading
other end of said guide shoe to interferingly engage sheet
materials passing over the latter, whereby movement of the tool
through said material serves to feed material over the leading end
of said guide shoe and against said cutting edge to sever the same
in a plane disposed in acute angular relationship to the
formational plane of said sheet material, a secondary cutting edge
formed on a lateral margin of said blade, in intersecting
relationship with said first cutting edge and adapted for use in an
inverted operating position for the tool, and additional guide
means formed on the outer end of said holder means for locating the
second cutting edge in a plane of angularity coincident with the
plane of severance effected by said first cutting edge.
2. A hand operated tool for cutting angulated butt seam edges in
wall covering materials and the like comprising: an elongated
planar guide shoe formed with an opening therethrough and having a
bottom planar guide surface engageable with an underlying wall to
guide the tool in its normal operating position, a generally planar
body member affixed to said guide shoe adjacent one end thereof
such that the plane of said body member lies in acute angular
relation to the plane of said guide shoe and guide surface, an
elongated arm portion formed on said body member in overhanging
spaced alignment with the longitudinal axis of said guide shoe and
opening, such that the longitudinal axis of said arm portion
intersects the plane of said guide shoe and guide surface; holder
means affixed to said arm portion and comprising a pair of parallel
spaced wall portions for slidably receiving and holding a cutting
blade in the plane of said body member, handle means removably
mounted on said body member in angular disposition to said holder
means and guide shoe spaced means on said body member and holder
means for adjustably mounting and holding said handle means in
selected positions of elevation relative to said guide shoe, and a
cutting blade frictionally mounted in said holder means and having
a first cutting edge in the plane of said body member and parallel
to the longitudinal axis of said arm portion to subtend in
bi-angular intersecting relationship with the plane of said guide
surface, said cutting edge invading said opening rearwardly of the
leading other end of said guide shoe to interferingly engage sheet
materials passing over the latter, whereby movement of the tool
through said material serves to feed material over the leading end
of said guide shoe, against said cutting edge and between said
handle means and guide shoe to sever the same in a plane disposed
in acute angular relationship to the formational plane of said
sheet material.
Description
BACKGROUND OF THE INVENTION
Under present practice, butt seams for heavy gauge wall covering
materials, by way of example, are usually made by cutting the
material normal or at right angles to the material face or plane.
This is generally accomplished by means of a straight edge, guiding
a razor blade knife. In some instances a so-called "shoe knife" is
used. Such a tool has a guide shoe that rides underneath the
material and means for holding a knife blade in a plane normal to
the material and in subtending angularity so that one lower corner
of the knife edge passes through the material and into a clearance
slot formed in the guide shoe. By pushing such a tool along a
desired line of cut, one or more layers of material may be severed
with matching edges formed substantially at right angles to the
plane of the material.
In both of the foregoing outlined practices, the right angular
edges of the material are adapted to abut one another in forming a
butt seam between adjacent wall covering sheets. In the case of
wall coverings having a dark colored facing, in particular, such
right angular abutted edges usually exhibit an unsightly gap or
line of abutment, due, principally to the light colored backing
layer of the material and the inexactness of matching edges at the
line of abutment therebetween. Consequently present practices
produce butt seams which are quite noticeable to the eye.
In recognition of the above outlined problems and difficulties
experienced in the known art and the almost impossible task of
providing seamless or non-visible butt joints under present known
practices, particularly with wall coverings having a dark facing
color or background, the present invention has been developed to
provide an improved tool capable of effecting seamless edges
between adjacent material pieces or sheets. Specifically, the tool
of this invention provides an undercut edge on the material which
is formed at an angle to the plane of the material so that adjacent
edges may overlap in effecting a butt seam. Consequently, the
finished butt seam is quite invisible even under careful
inspection. While the utility of the improved tool of this
invention is especially apparent when working with dark colored
wall covering materials, its principles and advantages apply
equally in cutting cork, carpet, grasscloth, canvas, plasticized
wall coverings and like materials.
SUMMARY OF THE INVENTION
In brief, the present invention is directed to an improved
combination of elements for a hand operated cutting tool
comprising, a planar body member angularly affixed to a planar
guide shoe and having a manually engageable handle means mounted
thereon. A cutting blade holder is provided on the body member for
removably mounting a multiple edge cutting blade in coplanar
relation with the body member and in bi-angular intersecting
relation with the guide shoe. Guide means are provided for guiding
materials over the guide shoe and against one of the cutting edges
in the normal operating position for the tool. Additional guide
means are provided adjacent the second cutting edge for operation
of the tool in inverted position whereby the second cutting edge
may be aligned with a straight edge for effecting a matching
angulated cutting of the material.
An important object of this invention is to provide an improved
tool for severing wall covering materials and the like whereby
severed edges thereof may be abuttingly overlapped in effecting a
relatively invisible butt joint or seam between adjacent material
pieces.
Another important object of this invention to provide an improved
cutting tool for severing wall covering materials and the like
having a dual edge cutting blade and guide means for effectively
severing such materials at a predetermined angle of cut with
respect to the plane of the material by operation of either of the
cutting edges.
Still another object of this invention is to provide an improved
cutting tool having a replaceable cutting blade held in bi-angular
disposition with respect to material to be severed thereby.
Having thus described the present invention, the above and further
object features and advantages thereof will be recognized from the
following detailed description of a preferred embodiment thereof
taken in conjunction with the accompanying drawings.
DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a perspective view of the improved tool of this invention
showing the major elements thereof except for the handle means;
FIG. 2 is exploded perspective view showing the various elements of
the improved tool of this invention;
FIG. 3 is a side elevational view of the assembled tool;
FIG. 4 is a cross-sectional view thereof taken substantially at
vantage line 4--4 in FIG. 3 and looking in the direction of the
arrows thereon;
FIG. 5 is an enlarged end elevational view illustrating the
overlapping relationship of abutting edges for materials severed by
a tool of this invention;
FIG. 6 is an enlarged partial view in cross-section and elevation
taken substantially from vantage line 6--6 of FIG. 3 and looking in
the direction of the arrows thereon;
FIG. 7 is a perspective illustration of an auxiliary tool employed
for mounting and removing cutting blades;
FIG. 8 is a perspective view illustrating the operation of the tool
of this invention in its inverted position; and
FIG. 9 is an enlarged cross-sectional view illustrating the guide
means associated with the inverted operating position for the tool
as viewed substantially from vantage line 9--9 of FIG. 1 and
looking in the direction of the arrows thereon.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning now to the particulars and details of the preferred
embodiment illustrated in the drawings, initial reference is made
to FIGS. 1, 2 and 3. As therein shown, the preferred tool of this
invention, indicated generally by numeral 15, comprises a main body
member 16 adapted to support a handle member 17 and a blade holder
18. A cutting blade 19 is mounted in the holder 18 to angularly
subtend therefrom so that one cutting edge thereof intersects the
plane of a planar guide shoe 20 affixed to the main body 16 and
carrying guide means 21 to operate with the handle member in
guiding material past the cutting edge of the blade 19 in
operation.
As best shown in FIG. 2 of the drawings, the body member 16 is
formed as a unitary metal stamping of generally planar
configuration with minor exceptions as will be hereinafter pointed
out. The body member has a central planar body portion 26 having an
elongated generally rectangular tail portion 27 tending angularly
outwardly from one upper marginal corner thereof for interfitting
engagement with the handle member 17. In similar fashion, extending
angularly outwardly of the opposite upper corner of the body
portion 26, is an elongated arm portion 28, the outer end of which,
as indicated at 29, is formed at an angle or bias to the
longitudinal axis of portion 28 to interfit with the blade holder
18, as will be described in greater detail hereinafter. A stop
shoulder 30 is formed at the junction of the base end of the arm
portion 28 and body portion 26. In the particular embodiment
illustrated in FIG. 2, such shoulder 30 is disposed at right angles
to the longitudinal axis of arm portion 28. Alternately, shoulder
30 may be disposed at an angle to such longitudinal axis (see the
dotted line indication at 30a in FIG. 2). In still other instances,
depending on the blade 19 employed, shoulder 30 may be located at
30b, again as illustrated in dotted lines in FIG. 2. Below the
shoulder, the lefthand lateral margin of the body portion 26 as
seen in FIGS. 1, 2 and 3, is formed as a curvilinear edge 31.
Preferably, the curvilinear edge 31 is rounded over or formed by
angularly intersecting edge surfaces so as to provide a means for
engaging the material to be cut and separating the same to clear
the body portion 26. Along the bottom edge 32 of body portion 26 is
a projecting ear portion 33 of substantially rectangular
configuration. Ear portion 33 acts as a mounting means for affixing
the body portion to the guide shoe 20 in assembly. Importantly, ear
portion 33 is formed out of the plane of body portion 26 and
preferably at an angle B of substantially 45.degree. with respect
thereto. Similarly edge 32 is formed in a plane at 45.degree.
angularity with respect to the plane of body portion 26 to meet the
upper face of shoe 20 in assembly (see FIG. 6).
The righthand lateral marginal edge 34 of body portion 26 is
distinguished by a pair of parallel spaced rectangular notches or
slots 35 and 36, the former being at the base of tail portion 27
where the same intersects the margin 34 of body portion 26, while
notch or slotted opening 36 is disposed between slot 35 and the
lower angulated edge 32 of the body portion 26.
As best shown in FIG. 2 of the drawings, the handle member 17 is
formed by a short length of generally cylindrical metal tubing
having an angular bend intermediate its ends. The front or leading
end of the handle, as indicated at 40, is cut at an angle with
respect to the longitudinal axis of a first cylindrical portion 41
of the handle member.
The upper side of portion 41 is formed with an elongated slotted
opening 42 through which the upper margin on edge of the body
member 16 extends in certain of the operating positions for the
handle member 17 as will appear in greater detail hereinafter. On
the bottom side of the cylindrical portion 41 an additional or
second slotted opening 43 is provided (see FIG. 2) for clearing the
main body portion 26 in positioning of the handle on member 16.
Opening 43 registers with opening 42, but is shorter in length. As
will be best appreciated from FIG. 3, the mounting of the handle
member 17 on body member 16 involves insertion of tail portion 27
of the latter into the hollow interior of the handle member so that
the cylindrical portion 41 embraces the body member 16, with
portions of the handle beyond the terminal end 44 of the lower
slotted opening 43 engaging one of the positioning notches 35 or 36
as the case may be. Preferably a bicycle type grip of rubber or
like material, indicated generally at 45 is mounted over the
exterior of the metal handle member 17 to provide convenient manual
engagement thereof. To that end, the grip 45 is preferably provided
with spaced finger grip indentations 46, 46 on one side which are
particularly useful in the inverted operating position of the tool,
as will appear hereinafter.
Mounted over the arm portion 28 of the body member is the blade
holder 18. As shown best in FIGS. 1 and 3 of the drawings, the
blade holder 18 comprises a reentrantly folded metal member of
substantially U-shape cross-section (see FIG. 4) having opposed
upper wall portions 50, 51 disposed generally parallel to one
another and interconnected by an integrally related folded upper
edge margin 52 therebetween; the two wall portions 50, 51 closely
embrace the arm portion 28 therebetween when the holder member 18
is mounted on the latter. Spot welds 53, or other fastening means
are employed to rigidly affix the holder member 18 to the arm
portion 28.
In addition to the upper wall portions 50, 51, the holder member 18
includes a pair of parallel spaced lower wall portions 54 and 55
(see FIG. 4) separated sufficiently to receive and frictionally
hold the blade member 19 therebetween. It will be noted that each
of the wall portions 54 and 55 is provided with an inwardly turned
lower edge portion 54a and a pair of spaced dentent identations 56,
which project inwardly of the space between wall portions 54, 55 to
actively engage and lock the blade 19 in position therebetween. The
holder edge portions 54a serve to guide the covering materials past
the blade 19.
Importantly, the outer ends of the wall portions 50, 51 and 54, 55
are formed or cut at an acute downwardly sloping angle relative to
the longitudinal axis of the holder member 18 with the end edges 57
and 58 thereof being beveled inwardly at substantially 45.degree.
to act as a guide means for engaging a straight edge in the
inverted operating position for tool 15, as will be amplified
hereinafter (see FIG. 9).
Mounted on and protruding from the exterior faces of the wall
portions 50, 51, 54 and 55 of the blade holder are a plurality of
outwardly projecting pairs of locating beads 60, 61 and 62 which
are spaced from one another and aligned in registeringly opposed
pairs on opposite exterior walls of the holder member. As
illustrated in FIG. 3, such bead projections 60-62 are adapted to
engage the inner and outer walls of the handle portion 41 adjacent
the outer tip end thereof in its several operating positions.
Specifically, as shown in that figure, it will be recognized that
the uppermost bead projections 60, 60 limit the upper position for
the handle, as shown in full lines therein, by engaging the
exterior wall of the handle's cylinder portion 41, immediately
adjacent the outer tip end thereof and on opposite sides of the
slotted opening 42 therein. At the same time the beads 61
underengage the inside walls of the cylindrical portion 41 opposite
its areas of engagement with projections 60. These projections in
conjunction with the upper locating slot 35 of the body member
serve to frictionally hold or wedge the handle member in a first or
upper operating position. In similar fashion when the handle member
is engaged with the lower notched opening 36 of the body member,
the outer tip end thereof is interfitted between the adjacent bead
projections 61, 62 on opposite sides of the holder member, as
indicated by the dotted line showing for the handle member in FIG.
3. This variation in the positioning of the handle member serves to
accommodate materials of different thickness with the lower
exterior portions of the handle's cylindrical portion 41 acting as
a guide means for directing the material past the knife tool as the
latter effects its cut. In this respect it will be readily
appreciated that in the upper positioning of the handle member 17
whereat the same is engaged between the beads 60, 61 and with the
upper locating notch or slot 35, the line of flow for materials
past the knife blade 19 is substantially in accordance with the dot
dash line F in FIG. 3.
The cutting blade 19, is best illustrated in FIG. 2 of the drawings
showing blade 19 and two modified versions 19a and 19b of a
multiple edge cutting blade. As shown in FIGS. 1 and 2, blade 19
comprises a planar blade body 64 made of surgical steel or the like
and provided with an elongated slotted opening 65 disposed
substantially medially of its length and extending upwardly toward
the upper margin thereof. A reentrantly formed reinforcing backing
member 66 is folded to fit snugly over the upper margin of the
blade body 64 and is affixed thereto as by spot welds 67, at least
two of which weld zones are indented and opposite the detent
projections 56 of the blade holder for cooperating engagement
therewith in the mounted position of the blade in the holder. The
lefthand or leading edge 68 of the blade comprises a first
angularly ground cutting edge which intersects with a second
cutting edge 69 formed along the bottom margin of the blade body
64. It will be noted that the back member 66 is cut or chamfered at
one end to coincide with the cutting edge 68 in the specific form
of blade indicated at 19 in FIGS. 1 and 2.
As best illustrated in FIGS. 1 and 3, blade 19 is adapted to fit
between the wall portions 54 and 55 of the holder 18, with the
rearward end 70 of the blade backing member abuttingly engaging
shoulder 30 of the holder body and the intersection of the two
cutting edges 68 and 69 thereon projecting forwardly of the holder
member. Inasmuch as the arm portion 28 on the holder body is formed
to diverge upwardly at an angle with respect to the horizontal in
an upright position for the tool's body member 16, it will be
appreciated immediately from an examination of FIG. 3 that the
blade 19 is held by the holder at an angle to the horizontal so
that one lower corner of cutting edge 69 thereon intersects the
plane of the guide shoe 20.
The modified blade 19a as illustrated in FIGS. 2 and 7, differs
from blade 19 principally in that the same is doubled-ended or,
that is, comprises three cutting edges 68a, 69a and 71a; cutting
edges 68a and 71a being disposed at an angle to the bottom linear
cutting edge 69a to permit reversal or reversed positioning of the
blade in the holder 18. It will be noted that the backing member
66a, which is affixed to the upper margin of the blade body 64a,
has ends formed at right angles to its longitudinal axis and
located beyond the angularly disposed cutting edges 68a and 71a. In
utiilizing the blade 19a the shoulder position 30a on the tool's
body portion 26 is employed to abuttingly engage and locate the
ends of the backing member 66a in the holder.
The second modified blade 19b illustrated in FIG. 2 is
substantially identical to blade 19a with the exception that the
backing member 66b thereon has its ends chamfered or cut at an
angle to conform to the angular disposition of the end cutting
edges 68b and 71b. Shoulder 30b of the tool's body portion 26
serves to locate blade 19b in the holder. Basically it will be
recognized that the formation of the two modified blades 19a and
19b is such that the body portions theeof are formed substantially
as trapezoids. It further will be appreciated that each of the
blades is adapted to be frictionally received between the wall
portions 54 and 55 of the holder member and that the detent
indentions 56 in such walls cooperate with the spaced depressions
of indentations 67 formed in the backing members of the respective
blades as above mentioned, thus resiliently locking the blades in
mounted position in the holder.
As previously noted, the disposition of a blade in the holder is
such that one lower corner of cutting edge 69 intersects the plane
of the guide shoe 20 when the latter is assembled with the main
body member 16. As will be noticed best from an examination of
FIGS. 1 and 2 in particular, the guide shoe 20 comprises a
generally elongated planar body portion 72 rounded over at its ends
73 and 74. The leading or front end 74 of the shoe body 72 is
curvilinear and chamfered at an angle to the main plane of its
formation to provide an entry or nose portion for the leading edge
of the shoe to assist its movement beneath material to be cut. A
first elongated opening 75 is formed generally on the longitudinal
center line of the body portion 72 to accommodate the passage of
the intersecting blade 19.
Mounted directly over the slotted opening 75 is a first guide means
21 comprising a bifurcated leaf spring having a slotted opening 78
extending inwardly of one end thereof and a mounting platform
portion 79 at its opposite end. Portion 79 is configured to fit
registeringly over the nose end 74 of the guide shoe body portion
72. Spring means 21 is held to the upper face of the end portion 74
by an overdisposed mounting plate 80 which is spot welded to the
body portion 72. The arms of the leaf spring guide angle upwardly
from the guide shoe to assist the feeding of the material across
the cutting edge 69 of the blade 19, as best shown in FIG. 3 of the
drawings. The slotted opening 78 in the guide means 21 of course
accommodates passage of the cutting blade 19 therethrough and into
the underlying clearance opening 75 of the guide shoe.
As noted previously, the guide shoe is adapted to be affixed to the
bottom margin of the body member 16 by inserting the projection
portion 33 on the latter into a registeringly aligned slotted
opening 81 formed through the guide shoe body portion 72. It will
be recognized that opening 81 is slightly off center so that when
assembled with the body member 16, the plane of the blade means
will align with the central axis of the clearance opening 75.
Inasmuch as the portion 33 of the body member 16 is formed at
45.degree. or thereabouts with respect to the plane of the body
portion 26, mounting of the latter on the shoe member disposes the
plane of the body portion as well as the cutting blade at an angle
B of substantially 45.degree. with respect to the guide shoe. This
relationship is best illustrated in FIG. 6 of the drawings. Once
assembled the guide shoe is affixed to the body portion 26 as by
brazing or welding to provide a rigid fixed connection between the
guide shoe and the body member 16.
As thus described, it will be understood that the tool 15 of this
invention is particularly distinguished by virtue of the fact that
the cutting blade 19 thereof is held in bi-angular relationship to
the guide shoe 20, that is to say, a first attack angle labeled A
in FIG. 3 disposes the blade at an angle to the line of advance of
the shoe so as to gradually infeed the material to be cut across
the cutting edge 69 thereof. Simultaneously the plane of the blade
19 is held at approximately 45.degree. to the plane of the guide
shoe 20 or at an angle B as illustrated in FIG. 6. With this
bi-angular arrangement of the blade, it will be understood that
material 85 is severed or cut as a bias or angle to the plane of
the material's formation, thus lapping edge portions 86 and 87 at
adjacent edges of the material are provided to permit a
substantially seamless butt junction therebetween. It further will
be appreciated that the two matching edges 86 and 87 of adjacent
material pieces conveniently may be produced by overlapping two
pieces and simultaneous cutting the same along the desired cut line
in the manner illustrated in FIG. 4. In any event, the
inter-matching 45.degree. faces of the bias cut edges 86 and 87
effectively overlap in assembly with little or none of the backing
color, such as in layer 88 (FIGS. 5 and 9) readily visible at the
junction of the outer layer 89 of the material, even when cutting
wall covering materials having a dark background, for example.
In considering the operation of the present invention, its method
of effecting a desired overlapping butt joint is as above described
and illustrated in FIG. 4 of the drawings. It will be appreciated,
however, that in cutting adjacent sheets or lengths of the wall
covering materials mounted in overlapping fashion, production of a
seamless butt joint therebetween, in the normal operating position
of the tool 15, can be effected except for the positions of the
tool whereat the guide shoe 20 interferes with adjacent walls,
molding, etc. This would occur, as, for example, at the base line
of the room adjacent baseboards, and at the ceiling line adjacent
the ceiling wall. Stated another way, where obstructions prevent
the passage or movement of the guide shoe sufficiently to permit
the cutting edge of the knife blade to move through the material,
completion of the cut must be made in some other fashion. To
accommodate this problem inverted positioning of the tool is
contemplated and for this purpose the second cutting edge 68 on
blade 19 is utilized. As will be noted best from FIG. 3, with the
blade 19 mounted in a holder 18, cutting edge 68 projects at an
obtuse angle with respect to leading edges 57 and 58 of the holder
means. By inverting the tool or that is turning the same upside
down in the manner illustrated in FIG. 8 of the drawings, cutting
edge 68 is available and may be inserted through the material as at
the ceiling of the room to complete the unfinished cut barred by
the presence of the guide shoe 21. In accomplishing this, it is
essential that the angle of the cut match the line of severance
between the materials previously made by the normal cutting
position of the tool. To this end with the tool of this invention
inverted, a straight edge, such as the blade of a wide scraper 90
(see FIG. 9), may be placed parallel to the desired line of cut and
one or the other of the two 45.degree. undercut edge surfaces 57 or
58 guided thereagainst to dispose the tool at a 45.degree. with
respect to the plane of the material. By drawing the knife
downwardly from the ceiling line then the overlapping edge
formation may be completed. In a similar fashion completion of the
cut at or near the base line of the wall may be effected, bearing
in mind that the tool may be disposed with either surfaces 57 or 58
of the holder engaging the straight edge for guidance.
Inasmuch as it is fully contemplated that the blade means 19 and
its modified forms will be resiliently held in the holder by means
of the cooperating detent indentations 56 and the depressions 67 of
the holder and blade, respectively, it has been found convenient to
provide a tool to assist in the insertion and removal of the blade.
To this end the tool 95 as illustrated in FIG. 7 is provided having
a generally cylindrical manually engageable handle portion 96 with
an opening 97 near one end for hanging convenience and including a
generally flat, key-shaped blade 98 extending from one end of the
handle 96. The blade 98 enters the central slotted opening 65 of
the blade body in the manner indicated in FIG. 7. By pushing
sideways on the blade the tool permits a safe injection or
rejection of the blade into and out of the holder 18.
From the foregoing it is believed that those familiar with the art
will readily understand and appreciate the unique features and
operational advantages provided by the improved tool of this
invention and while the same has been described in association with
a particular preferred embodiment as comprising the best mode
presently contemplated to enable those skilled in the art to
practice the invention, it will be appreciated nevertheless that
the concepts and features involved therein may depart from the
specifics described hereinabove without materially departing from
its inventive purview.
* * * * *