Apparatus for cutting V-grooves in mats

A cutting unit and associated mat cutting apparatus are provided for cutting V-grooves in a mat board or the like. The cutting unit is mounted on a mat cutter and includes a pair of cutting blade holders attached to a frame. Each blade holder mounts a cutting blade therein with an exposed tip. The blade holders are movable between a lowered position relative to frame where the tips are adjacent one another and form a V pattern which intersects the mat board and a raised position. The cutting unit is mounted for precise movement along the guide of the mat cutter whereby a V-groove is precisely cut during movement as the cutting blade holders are held in the lowered position. Preferably, the blade holders are biased to the raised position and a retaining device is provided for retaining the blade holders in a lowered position, preferably locked in a lowered position. The tips of the blade are also preferably offset longitudinally relative to one another.

FIELD OF THE INVENTION 
The present invention relates generally to an apparatus for cutting 
V-grooves in picture mat boards or the like, and more particularly to an 
apparatus which precisely and conveniently cuts a V-groove in a mat board 
in one stroke. 
BACKGROUND OF THE INVENTION 
When providing a mat board for a picture, it is frequently desired to add a 
decorative V-groove or the like about the picture in the mat board. The 
creation of such V-grooves is a difficult and time-consuming task. 
One manner in which V-grooves can be provided is to use a mat cutter having 
a bevelled cutting blade movably mounted on a cutting guide disposed 
adjacent an associated mat guide. Using the bevel cutting head, a regular 
bevelled opening is cut in the mat. Then, the fallout piece is placed in 
the mat cutter and the bevelled cutting blade is used to trim 
approximately 1/16 inch off of each side. The fallout piece is then 
reinserted in the mat and tape is applied to the back of the fallout piece 
and mat to hold the fallout piece in place. Depending on the accuracy of 
the mat cutting apparatus, an attractive and fairly consistent V-groove is 
created in a mat in this manner. However, such a system for creating 
V-grooves requires a precise mat cutting system, as well as being 
relatively time consuming and subject to simple errors which can ruin the 
entire job. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, an apparatus is provided for 
cutting V-grooves in a mat board or the like simply and easily. The 
apparatus includes a mat cutter having a flat base as well as a 
positioning means for positioning the mat board on the base. The cutting 
apparatus is provided with a guide which is mounted to the flat base 
adjacent the positioning means. A cutting unit is suitably mounted on the 
guide by a frame mounting means. The cutting unit includes a frame and a 
pair of cutting blade holders. Each cutting blade holder has a cutting 
blade positioned therein with an exposed tip. A holder moving means is 
provided on the frame for moving the blade holders between a lowered 
position relative to the frame where the tips are immediately adjacent one 
another and the planes of the blades intersect at the tips to form a 
V-pattern and a raised position relative to the frame. Thus, a V-groove is 
precisely cut in the mat board provided on the base when the cutting unit 
is moved along the guide and the holder moving means is moved to the 
lowered position so that the tips engage the mat board. 
In the preferred embodiment, the holder moving means includes a holder 
mounting means for mounting each blade holder to the frame for rotation 
about a respective axis. Thus, the tips of the cutting blades are 
rotatable with the blade holders from the raised position to the lowered 
position where the tips are adjacent one another. In addition, the holder 
moving means includes a biasing means for biasing the blade holders about 
the respective axes of rotation to the raised position. A retaining means 
has been provided for retaining the blade holder means in the lowered 
position, such as a lock means which locks the holding means in the 
lowered position. The retaining means includes a lever, a pivot means for 
mounting the lever to the frame for rotation about an axis, and an 
engaging means attached to the lever for engaging the blade holders as the 
lever is rotated about the axis to move the blade holders from the raised 
position to the lowered position. Preferably, the engagement between the 
engaging means and the blade holders creates a moment about the pivot 
means due to the action of the biasing means. The lock means is then 
provided by positioning the axis of the pivot means to a side of the 
moment created by the biasing means when the blade holders are in the 
lowered position. This causes the moment to urge the lever to continue 
lowering the blade holders against a stop means provided for preventing 
the continued lowering of the blade holders when the blade holders are in 
the lowered position. 
In mounting the blade holders to the frame, it is also preferred that one 
of the tips of the blade is offset from the other tip in a longitudinal 
direction relative to the V-groove which is cut. With such an offset, the 
leading tip provided by such an offset is preferably used for the inside 
cut of the V. Then, when a corner is cut, the outside, trailing blade is 
moved the full length of the cut resulting in a slight overcut of the 
inside leading blade. However, when the mat is turned 90.degree. and the 
second V cut is made at the corner, an exact cut is made at the corner and 
most of the overcut of the inside of the V is cut off by the subsequent 
cut made by the outside blade in the new V-groove. The small remaining cut 
portion which is not removed by the subsequent V-groove is so small as to 
be unnoticeable. 
In the preferred embodiment, the guide includes a flat guide bar having a 
top surface and a guide rod attached to the top surface. The frame 
mounting means then includes a pair of frame portions on one side of the 
blade holders, with each frame portion including an aperture in which the 
guide rod is snuggly but slidably received. These frame portions also 
include bearing surfaces on either side of the aperture which slide along 
the top surface of the guide bar. Preferably, these bearing surfaces are 
individually adjustable in a direction perpendicular to the guide bar so 
that the depth and breadth of the V-groove is thereby adjustable. In 
addition, each frame portion includes two elements each of which forms a 
part of the aperture. An attaching means is then provided for attaching 
the two elements together to form the aperture in which the guide rod is 
snuggly received. With the attaching means, each frame portion and hence 
the frame are quickly and easily attachable and demountable from the guide 
rod. 
To provide for an easier making of the V-grooves, guide stops are 
preferably provided adjustably along the guide on respective sides of the 
cutting unit. The cutting unit then includes adjustable stop members on 
respective sides of the frame for engagement with these guide stops. 
It is an object of the present invention to provide an apparatus for 
cutting V-grooves which is simple to operate and which is easily used to 
cut V-grooves in a mat board to form a rectangular or other pattern. 
It is also an object of the present invention to provide an apparatus for 
cutting V-grooves in which the depth and hence breadth of the V-groove is 
easily adjusted. 
Other features and objects of the present invention are stated in or 
apparent from a detailed description of a presently preferred embodiment 
of the invention found hereinbelow.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
With reference now to the drawings in which like numerals represent like 
elements throughout the several views, an apparatus 10 for cutting 
V-grooves in a mat board 12 or the like is depicted in FIG. 1. In this 
embodiment of the present invention, apparatus 10 includes a C & H Mat 
Cutter 14 available from C & H Manufacturing of Jackson, Miss. Mat cutter 
14 includes a flat base 16 upon which mat board 12 rests. Mat cutter 14 
also includes a positioning means 18 for precisely positioning mat board 
12 on flat base 16. Positioning means 18 has a mat guide bar 20 which is 
mounted on a mounting arm 22. Mat guide bar 20 is perpendicular to 
mounting arm 22 and is adjustably mounted thereon by means of thumbscrew 
24. 
Positioning means 18 positions mat board 12 on flat base 16 relative to a 
guide 26. Guide 26 includes a guide bar 28 having a top surface 30 and a 
guide rod 32 attached to top surface 30. Guide 26 is mounted for movement 
forward and away from flat base 16 by means of a pair of parallel supports 
34 attached together by a handle 36. Supports 34 are pivotably attached to 
flat base 16 by hinges 38 at one side of flat base 16 so that guide 26 is 
easily raised above flat base 16 by grasping handle 36. This movement of 
guide 26 facilitates the insertion and removal of mat board 12 on a flat 
base 16. 
In order to easily cut V-grooves immediately adjacent the edges of mat 
board 12, positioning means 18 also preferably includes a first attachment 
40 which is removably and adjustably located on mat guide bar 20 by a 
thumbscrew 42. As shown, first attachment 40 includes an edge 44 parallel 
to mat guide bar 20 against which an edge of mat board 12 rests. First 
attachment 40 also includes a second edge 46 parallel to mounting arm 22 
which acts as a stop against which mat board 12 rests. To assure the 
parallel alignment of the edge of mat board 12 against edge 44, a second 
attachment 48 is provided on mat guide bar 20 by use of thumbscrew 50. 
Second attachment 48 includes an edge 52 which is spaced the same distance 
from mat guide bar 20 as edge 44 of first attachment 40. Thus, by 
positioning the edge of mat board 12 against both edges 44 and 52, mat 
board 12 is precisely positioned with an edge parallel to mat guide bar 20 
and precisely positioned a distance away from mounting arm 22 by edge 46. 
Attachments 40 and 48 further allow the easy use of adjustable stops 54 
and 56 which are conveniently mounted on cutter guide rod 32. As is known 
to those of ordinary skill in the art, stops 54 and 56 include adjustable 
stop ends 58 and 60. 
As shown in greater detail in FIG. 3, apparatus 10 includes a cutting unit 
62 which is mounted for movement along cutter guide 26. Cutting unit 62 
includes a frame 64 comprising two mounting arms 66 and two cross pieces 
68 which are mounted to form a suitable angle between each other for a 
V-groove, such as approximately 75.degree.. As shown further in FIG. 5, 
each cross piece 68 has a cutting blade holder 70 attached thereto in 
which a cutting blade 72 is provided. Each cutting blade holder 70 is 
mounted to cross piece 68 by a holder mounting means 74 for rotation about 
a respective axis. Conveniently, holder mounting means 74 is a screw 76 
which is threadably received in cross piece 68 and which includes a shank 
78 about which cutting blade holder 70 rotates. 
Cutting blade holder 70 is constrained to rotate between a raised position 
where tips 80 of cutting blade 72 are raised out of engagement with mat 
board 12 and a lowered position where tips 80 penetrate into mat board 12 
as depicted in FIG. 6. The movement of cutting blade holder 70 is depicted 
schematically in FIG. 5 as a difference between the solid lines shown for 
cutting blade holder 70 in the lowered position and the dotted lines 
outlining a portion of cutting blade holder 70 in the raised position. 
Each cutting blade holder 70 is constrained to move only between the 
raised and lowered position by means of a stop means 82. Conveniently, 
stop means 82 takes the form of a pin 84 extending through cutting blade 
holder 70 and into a curved slot 86 precisely positioned in cross piece 
68. Thus, pin 84 is constrained to move only between the ends of slot 86. 
Preferably, a biasing means 88 is provided to bias cutting blade holder 70 
to the raised position when pin 84 engages an end of slot 86. Biasing 
means 88 is preferably a spring 90 attached at one end to cross piece 68 
and at the other end to cutting blade holder 70 as shown. As an 
alternative, a stop screw can be provided adjacent a top edge of cutting 
blade holder 70. 
It should be appreciated that cutting blades 72 are precisely located in 
cutting blade holder 70 by means of a lower edge stop 92 and end stops 94. 
In addition, cutting blade 72 is firmly held in cutting blade holder 70 by 
a pressing member 96 having a thumbscrew 98 for adjustment which allows 
the insertion removal of cutting blade 72. Pressing member 96 has an end 
adjacent tips 80 to reinforce tips 80. The end of pressing member 96 is 
always aligned in this position because pin 84 also passes through 
pressing member 96 as shown. 
It should further be appreciated that cutting blade holders 70 are 
precisely positioned on respective cross pieces 68 so that one cutting 
blade holder 70 is slightly offset in a direction along cutter guide 26 
from the other. This results in one tip 80 being slightly offset from the 
other tip 80 along the length of cutter guide 26 by a short distance as 
depicted in FIG. 2. Preferably, this distance is approximately 1/32 inch 
and cutting blade holder 70 closest to mat guide bar 20 is the cutting 
blade holder slightly behind (in the cutting direction) of the other 
cutting blade holder 70. This offset of tips 80 allows for an easier 
cutting of a corner where two V-grooves meet, as explained subsequently. 
In order to move cutting blade holder 70 between the raised and lowered 
position about holder mounting means 74, a holder moving means 100 is 
provided. Holder moving means 100 includes a retaining means 102 which is 
used to retain cutting blade holders 70 in the lowered position. Retaining 
means 102 preferably includes a lever 104 which is mounted to mounting arm 
66 as shown by a pivot means 106 including a pin 108. Attached to lever 
104 is an engaging means 110 which preferably takes the form of short 
steel rod 112. 
As shown best in FIG. 4, steel rod 112 engages an edge 114 of each cutting 
blade holder 70 to move cutting blade holder 70 from the raised position 
to the lowered position within the limits of stop means 82. The use of 
lever 104 makes it easier to overcome the biasing of biasing means 88 
which pulls cutting blade holder 70 to the raised position. However, it 
should also be appreciated that holder moving means 100 further includes a 
lock means 116 for locking retaining means 102 in the position where 
cutting blade holder 70 are in the lowered positioned. Lock means 116 is 
provided by the location of pin 108 to one side of the force line F 
created by biasing means 88 acting through cutting blade holder 70 and 
steel rod 112. As shown in FIG. 4, force line F is located below pin 108. 
Therefore, a moment is created about pin 108 which urges, slightly, lever 
104 toward the lowered position and hence to the position where pin 84 and 
stop means 82 engages the end of slot 86. In this lowered position, 
biasing means 82 thus holds or locks lever 104 in the lowered position by 
the action of the moment created by biasing means 82. Obviously, as lever 
104 is raised slightly, force line F shifts to the other side of pin 108 
and lever 104 is thus urged upwards by biasing means 82 and biasing means 
82 thus completes raising of cutting blade holder 70. The raised and 
lowered position of lever 104 and the rest of retaining means 102 is 
depicted schematically by dotted lines in FIGS. 3 and 5. 
In order to facilitate the mounting of cutting unit 62 on cutter guide 26, 
a frame mounting means 118 is provided. Frame mounting means 118 includes 
an aperture 120 in each mounting arm 66 as shown best in FIG. 5. Frame 
mounting means 118 further includes a bottom bearing surface of each 
mounting arm 66 which mates with top surface 30 of cutter guide bar 28. As 
is also shown in FIG. 5, mounting arm 66 includes two elements 66a and 66b 
which together form aperture 120 and which have mating surfaces as shown. 
A thumbscrew 124 passes through element 66b and is threadably received in 
element 66a to securely attached elements 66a and 66b together. Thus, it 
will be appreciate that cutting unit 62 is simply mounted on cutter guide 
26 by initially removing element 66b from mounting arm 66 so that the 
remainder of cutting unit 62 is easily placed on cutter guide 26 with 
cutter guide rod 32 received in the half of aperture 120 in element 66a. 
Then, element 66b is attached to element 66a to complete the attachment of 
cutting unit 62 to cutter guide 26 in the trapping of cutter guide rod 32 
in aperture 120. Thus, aperture 120 and element 66a and 66b together with 
thumbscrew 124 form a suitable attaching means 126 for attaching cutting 
unit 62 to cutter guide 26. 
As also shown in FIG. 5, mounting arm 66 also includes an adjustment means 
128 for adjusting the position of cutting unit 62 on cutter guide 26. 
Adjusting means 128 includes a pair of polymeric rods 130 which are 
disposed in suitable apertures 132 located on either side of aperture 120. 
The extent, if any, by which polymeric rods 130 extend below bottom 
bearing surface 122 of mounting arm 66 is adjustable by means of 
respective set screws 134. Thus, if cutting unit 62 is slightly loosely 
fitted on cutter guide 26, set screws 134 can be suitably adjusted to 
extend polymeric rods 130 out of mounting arm 66 to achieve a tight 
sliding fit of cutting unit 62 to cutter guide 26. It should also be 
appreciated that adjustment means 128 provides for a slight adjustment of 
the depth of cut of tips 80 in mat board 12. As will be appreciated with 
reference to FIG. 5, where polymeric rods 130 on the side of cutter guide 
rod 32 closest to tips 80 are adjusted to extend from mounting arm 66, 
tips 80 will be raised slightly relative to mat board 12. On the other 
hand, where polymeric rods 130 on the other side of cutter guide rod 32 
are extended from bottom bearing surface 122 of mounting arm 66, tips 80 
will be lowered somewhat into mat board 12. While it is contemplated that 
such an adjustment of the depth of the V-groove cut by tips 80 will not 
generally be needed, it should be appreciated that adjustment means 128 
does provide this additional possibility. 
Cutting unit 62 also includes adjustable stops 136 and 138. Adjustable 
stops 136 and 138 include respective threaded bolts 140 and 142 which are 
threadably received in a respective mounting arm 66 and which extend 
outwardly from cutting unit 62. Bolts 140, 142 are held in place after 
threaded adjustment by respective nuts 144 and 146 which engage the 
associated mounting arm 66. Adjustable stops 136 and 138 are designed to 
engage respective stops 54 and 56 on cutter guide bar 32 and thus to 
provide very precise cutting strokes along cutter guide 26 as desired. 
In operation, cutting unit 62 functions in the following manner after 
attachment to mat cutter 14. Where stops 54 and 56 are not to be used, it 
is a simple matter to initially mark mat board 12 in pencil where it is 
desired to have a V-groove cut. Then, by appropriate positioning of 
positioning means 18, cutting unit 62 is used to cut the V-groove along 
one penciled line. It should be noted that cutting unit 62 is initially 
located at the end of the line furthest from mounting arm 22. At this 
position, holder moving means 100 is used to move cutting blade 72 from 
the raised position to the lowered position where tips 80 penetrate mat 
board 12. This is simply done by moving lever 104 around pivot means 106 
until lever 104 will no longer move due to the action of pin 84 contacting 
the end of slot 86. Cutting unit 62 is then manually drawn toward mounting 
arm 22 the desired distance at which time lever 104 is raised and tips 80 
are withdrawn from mat board 12. The remaining cuts are then made in mat 
board 12 as appropriate. 
If stops 54 and 56 are used with mat cutter 14, it is also possible to 
provide for over cuts or under cuts where desired using cutting unit 62 
without changing the position of stops 54 and 56. This is simply done by 
use of adjustable stops 136 and 138 by loosening the appropriate bolt 144, 
146 and either advancing or retreating respective bolt 140 or 142 to the 
desired over cut or under cut position. 
Depicted in FIGS. 7 and 8 are two of many different examples of V-groove 
patterns which can be cut in a mat board by apparatus 10. In FIG. 7, a mat 
board 150 is shown in which a rectangular V-groove 152 has been cut around 
an opening 154. In FIG. 8, a more elaborate design of V-grooves is shown 
in a mat board 156. Mat board 156 has a keystone corner V-groove pattern 
158 which is easily cut using detachable stops 54 and 56. 
Depicted in FIGS. 9 and 10 is a stabilizing means 160 for cutting unit 62. 
As shown, stabilizing means 160 comprises two rollers 162 which are 
mounted to respective brackets 164. Each bracket 164 is mounted to a 
respective element 66a of mounting arm 66 by screws 166 which are normally 
used to mount cross piece 68 to respective element 66a. Rollers 162 are 
mounted to brackets 164 by suitable axles 168. 
In order to accommodate different size mat boards, stabilizing means 160 is 
adjustable to raise or lower the height of rollers 162 above flat base 16. 
This is accomplished by use of slots 170 which are provided in each 
bracket 164 and through which screws 166 extend. Thus, by loosening screws 
166, the height of each roller 162 is adjustable as desired. After 
adjustment, screws 166 are tightened to hold bracket 164 in the adjusted 
position. 
When stabilizing means 160 is attached to cutting unit 62 and adjusted, as 
shown in FIG. 10, rollers 162 ride along mat board 12 as cutting unit 62 
is moved along cutter guide rod 32 and cutter guide bar 28. As stabilizing 
means 160 is provided at the end of cutting unit 62 furthest from the 
support provided by cutter guide bar 28 and cutter guide rod 32, the ends 
of elements 66a are thus stabilized as rollers 162 ride along mat board 12 
during cutting. This results in stabilizing the movement of cutting unit 
62 and thus a smoother movement which results in better control of the 
width and depth of the V-groove being cut. 
Although the present invention has been described with respect to an 
exemplary embodiment thereof, it will be understood by those of ordinary 
skill in the art that variations and modifications can be effected within 
the scope and spirit of the invention.