Note: Descriptions are shown in the official language in which they were submitted.
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I~AT BOARD CUTTER WITH KNIFE BL~DE SECURING SAFETY PIN
Technical Field
The present invention relates to mat board cutters, and
particularly to means in a mat board cutter for retaining a knife
blade in a pivot block pivotably mounted on a slidable cutter
carrying body.
Background Art
U.S. Patent No. 4,036,486 describes a mat board cutter
by which a mat board is cut to have a desired peripheral size to
fit within a desired frame and to have a desired central opening
though whicha picture being framed is visible.
As described in greater detail in U.S. Patent No.
4,036,486, cutting the ma-t board requires sliding a cutter-carrying
body along a guide rail with a knife blade included in a cutter
device or assembly pivotably carried on the body in engagement
with the mat, which mat is held in a predetermined position by
abutment means on a base and a clamp bar on which the guide rail is
mounted.
The knife blade included in the cutter assembly is thin
and has a truncated pyramidal periphery with a cutting edge along
its base, opposite end edges converging from its cutting edge, and
a top edge parallel to its cutting edge. Also included in the
cutter assembly is a pivot block having a socket receiving the
knife blade with an end portion of the knife blade and its cutting
edge projecting out of the socket, and means in -the form of a thumb
screw adapted to bear against one side surface of the knife blade
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for releasably Eixing the kni~e blade in the socke-t. Means are
provided for mountlng the pivot block on the cutter-carrying
body for p.ivotal movemen-t be-tween a disengaged posltion with the
projecting portion of the knife blade spaced Erom a mat board
on the cutter, and an engaged position with the kniEe blade
engaged with the mat board. With this design, the possibility
exists that if
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~he thumb screw is not securely tiyhtened or works loose
during use oE the mat board cut~er, tlle kniEe blade can
slide from withing the socket and move to a position at
which it can injure a user.
Disclosure of Invention
The present invention provides a cutter assembly
for a mat board cutter of the t~pe described above which
includes means for retaining the knife blade in the socket
in the pivot block even though the thumb screw should be or
become loosened, and to thereby restrict injury to a user
of the mat board cutter.
According to the present invention there is
provided an improved mat board cutter of the type having a
base with abutment means for positioning a mat board
thereon, a clamp bar for clamping the mat board on the
base, a guide rail on the clamp bar and a cutter-carrying
body slideably mounted on the guide railO Also included is
at least one cutter assembly including a thin knife blade
having a truncated pyramidal periphery with a cutting edge
along its base and opposite end edges converging from its
cutting edge, and a pivot block having a socket receiving
the knife blade with an end portion of the blade including
a portion of its cutting edge projecting out from the pivot
block, and means for releasably Eixing the knife blade in
the socket. Means are provided ~or pivotably mounting the
pivot block on the cutter-carrying body for movement
between a disengaged position with the kniEe spaced from
the mat board and an engaged position with the kni~e
engaged with the mat boardO
The improved cutter includes a safety pin having
a transverse groove opening through one sideO The pin is
mounted on the pivot block for movement along a path
through and transverse of the socket receiving the knife
blade between a blocking position with the groove spaced
from the socket and a portion of the pin positioned to
engage the outermost end edge oE tne blade in the socket to
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retain the blade in the socket upon release of the means
for releasably fixing the blade in the socket, alld a
release position with the groove aligned with the socket to
permit movement of the knife blade through the groove and
out of the socket upon release of the means for releasably
fixing the knife blade in the socket; and means for biasing
the pin to its blocking posi-tion.
As illustrated, the safety pin has a head at one
end, the end portion of the pin opposite the head is
slidably mounted in the pivot block, and the means Eor
biasing the pin to its blocking position is a coil spring
around the pin between its head and the pivot block.
Brief Description of Drawing
.
The present invention will be further described
with reference to the accompanying drawing wherein like
numbers refer to like parts in the several views, and
wherein:
Fiyure 1 is a fragmentary perspective view of a
mat board cutter including a cutter assembly according to
the present invention;
Figure 2 is an exploded perspective view of the
cutter assembly according to the present invention shown in
Figure l; and
E`igures 3 and 4 are end views of the cutter
assembly of Figure 1 shown with a safety pin respectively
in a blocking and a release position.
Detailed Description
Referring now to the drawing there is shown a
portion of a mat board cutter 10 including an improved
cutter assembly 11 according to the present invention
pivotably mounted on a cutter-carrying body 12.
The mat board cutter 10 is generally the same as
the mat board cutter described in U.S. Patent No
4,036,436, -u~ r~t~-h~in by-refe~en6~ in that it
comprises a base (not shown) with abutment means for
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positioning a mat board thereon; a clamp bar 18 for
clamping the mat board on the base; a guide rail 20 fi.xed
on the clamp bar 18 having a cylindrical perlpheral guide
surface 22; the cutter-carryi.ng body 12 which hcls spaced
ends 26 and a bearing surface 28 defining a through opening
between its ends 26/ which bearing surface 28 receives the
guide rail 20 in close-fitting relationship so that the
bearing surface 28 of the body 12 can slide along and will
be guided by the peripheral guide surface 22 of the guide
rail 20; and two cutter assemblies including the cutter
device 11 which is mounted along a vertical side surface of
the body 12 and is thus adapted to make vertical cuts in
the mat board, and an additional cutter assembly 30 which
is mounted along an inclined side sur~ace of the body 12
and is thus adapted to make slanted cuts in the mat board.
Each o~ the cutter assemblies 11 and 30 includes a knife
blade 32 and 33 respectively and is pivotably mounted on a
different side surface of the cutter-carrying body 12 for
pivotal movement between a disengaged position with the
knife blacle 32 or 33 spaced from the mat board, and an
engaged position with the knife blade 32 or 33 engaged with
the mat board.
The improved cutter assembly 11 is best seen in
Figure 2. The cutter assembly 11 includes means in the
form of a safety pin 34 for retaining ~he knife blade 32 in
the rest of the cutter assembly 11 until the safety pin 34
is manually manipulated.
The knife blade 32 included in the cu-tter
assembly 11 is thin, and has a truncated pyramidal
30 periphery with a cutting edge 36 along its base, opposite
end edges 37 converging E~om its cutting edge 36 an~ a top
edge 38 parallel to its cutting edge 36r In addition to
the knife 321 the cutter assembly 11 also includes a pivot
block 40 including inner and outer separable portions 41
and 42 held together by two screws 44 and defining a socket
46 therebetween which opens through an end of the pivot
block 40 and receives the knife blade 32 with an end
portion of the knire blade 32 and its cutting edge 36
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projecting outwardly from the plvot block 40. Means in the
form o~ a thumb-screw 48 threadably engaged through the
outer portion 42 of the pivot block 40 along the socket 46
are provided Eor fixing the knife blade 32 in the socket 46
by pressing it against the inner portion ~1 o~ the pivot
block 40 when the thumb-scLew 48 is manually tightened.
The pivot block 40 is mounted on the body 12 by a pivot
bolt 50 that extends through its inner portion ~0 into the
body 12 for pivotal movement around the pivot bolt 50
between a disengaged position (to which the pivot block 40
is biased by a coil spring 52 between the pivot block ~0
and body 12) with the kni~e blade 32 spaced from the mat
board, and an engage position to which the pivot block 40
may be manually pressed against the bias of the spring 52
by use of a handle 54 at which the knife blade 32 is
engaged with the mat board.
The safety pin 34 for retaining the knife blade
32 in the socket 46 includes a main portion 56 and a head
57 on one end of the main portion 56, and has a transverse
groove 58 in the main portion 56 opening through one side
of the pin 34 so that the main portion 56 is cylindrical
except along the groove 58 where it is semi-circular. The
inner portion 41 of the pivot block ~0 has a opening which
slidably receives the cylindrical main portion 5~ of the
saEety pin 34 and the outer portion 42 of the pivot block
40 has a slot opening through its edge and aligned with the
cylincrical opening in the inner portion 41, which slot
will receive only the semi-circular portion of the safety
pin 3~ adjacent the groove 58, thereby mounting the sa~ety
pin 34 for movement along a path through and transverse of
the socket 46 between an outer or locking position to which
the pin 34 is biased by a coil spring 60 around the pin 34
between its head 57 and the outer portion 42 of the pivot
block 40 which is defined by engagement of the circular
por~ion of the safety pin 3~ at the end oE the socket 46
opposite its head 51 with the outer portion ~2 of the block
40; and an inner or release position to which the safety
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pin 34 can be manuaLly pressecl ayains-t -the bias o:E the sp:ring 60
which is defined by engagement of the circular por-tion oE safety
pin 34 at the end oE the socke-t 46 adjacent -the head 57 with the
ou-ter portion 42 of the block 40. A-t -the locking or outer posi-tion
of the safety pin 34, its cylindrical main por-tion 56 will ex-tend
across -the socket 46 adjacent the outer end edge 37 of the blade 32
and will preclude movement of that outer end edge 37 and -thereby
the knife blade 32 out of the socket 46.
In its inner or release position, however, the groove 58
will be aligned with the socket 46 allowing the ou-ter end edge 37
and the top edge 38 of the knife blade 32 to move through the
groove 58 and the kniEe blade 32 to move out of the socket 46.
Thus to remove the knife blade 32, a user must both
release the thumb-screw 48 and press the safety pin 34 inwardly to
its release position against the bias of the spring 60, and the
safety pin 54 will preclude movement of the blade 32 out of the
socket 46 even during use of the mat cutter should the thumb screw
48 become inadvertently loosened.
The cutter carrying body 12 is preferably of an improved
type having spaced opposed surfaces 64 de:Eining a slo-t extending
between its ends 26 and communicating along one edge with the
through opening defined by the bearing surface 28 in which the
guide rail 20 is received, and means provided by screws (not shown)
extending through the slot for adjusting the spacing between the
opposed surfaces 64 defining the slot to position the bearing and
guide surfaces 28 and 22 in close-fitting relatively slidable
relationship.
It will be apprecia-ted that modifica-tions can be made to
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the lmprovecl cutter ].1 wi-thout departing from -the spiri-t Or the
present invention. Thus -the scope of the presen-t .inven-t:ion should
not be llmited to the structure of the body as lllustrated, but
should include all structures described by the language of -the
claims and their equival.ents.
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