US 3768357 A
Apparatus is disclosed for cutting away the interior portion of a continuous mat at a 45 DEG angle relative to the plane of the mat to provide a continuous border with a beveled inner edge. A flat bed receives the mat and a knife mount is cantilevered above the bed with the knife being pivotally mounted thereon. An adjustable edge guide is located above the bed and slides beneath the cantilevered mount to define the width of border cut. The mount holds the knife in a plane which is inclined 45 DEG relative to the vertical and about 3 DEG relative to the edge guide with the trailing edge of the blade spaced further from the edge guide than the leading edge.
Claims available in
Description (OCR text may contain errors)
O m United btates Patent [1 1 [111 3,768,357
McBride Oct. 30, 1973 MAT CUTTING APPARATUS  ABSTRACT 76] Inventor: Morris M. McBride, 412 Oxford A aratus is disclosed for cutting away the interior l PP Road, Tower Lakes, Barrington, portion of a continuous mat at a 45 angle relative to HI. 60010 the plane of the mat to provide a continuous border with a beveled inner edge. A flat bed receives the mat Flled 1972 and a knife mount is cantilevered above the bed with  Appl. No.: 293,588 the knife being pivotally mounted thereon. An adjustable edge guide is located above the bed and slides beneath the cantilevered mount to define the width of  U.S.Cl 83/438, 83/468, 83/555, 4 border cut The mount holds the knife in a pane a 1 CI 83/581 i 2'6i g /3; which is inclined 45 relative to the vertical and about 3 relative to the edge guide with the trailing edge of  Field of Search 83/468, 555, 564, the blade Spaced further from the edge guide than the 83/58], 648, 733, 438 leading edge  References Cited UNITED STATES PATENTS 3 13 10 Claims, 5 Drawing Figures 9/1970 Ellerin 83/581 X Primary Examiner-J. M. Meister Att0rney.lames J. Hill PAIENTEDBBI s an 1768,35?
SHEET 2 BF 2 1 MAT CUTTING APPARATUS BACKGROUND AND SUMMARY The present invention relates to an apparatus for cutting sheets of cardboard or pressed paper having a thickness of approximately one-sixteenth to one-eighth in. Such sheets are commonly referred to as mats; and they are used to provide borders for framing photographs or art work. It is particularly desirable in such borders to have the border remain continuous with no entry slits when the center is removed, and it is also desirable to have the inner edge of the border mat forming a beveled or inclined Surface of approximately 45 with the surface of the mat to provide a smooth transition between the surface of the photograph or art work being framed and the outer surface of the raised border which is superimposed on the photograph when it is framed.
One of the difficulties associated with a mat cutter of this type is to provide a clean beveled edge at each inner corner of the border without cutting into the border areaitself. One commercially available apparatus for forming borders is quite expensive and employs the principle of moving the cutter relative to the mat.
The apparatus of the present invention includes a flat bed for receiving the mat to be cut. A knife is cantilevered above the bed and it is actuatable by means of a handle between an upper set-up position and a lower cutting position. Ari adjustable guide edge is located above the bed and slides beneath the cantilever mount for the knife to define the width of the border being cut. The cantilever mount holds the knife in a plane which. is inclined at 45 relative to the vertical and about 3 relative to the guide edge with'the trailing edge of the blade spaced further from the guide edge than the leading edge. The knife is pivotally mounted so that the handle is rotated to its operative position. I have discovered that the 3 angle which the plane of the knife blade makes relative to the edge being cut is highly advantageousin achieving a clean, evenly mitered corner where the two inner beveled edges meet in forming a mat. This angle is further advantageous in providing an entry of the knife into the mat which is unnoticed after the mat is cut.
After the guide edge is adjusted toprovide the proper border width, the mat is placed on the bed against the guide edge and at a measured distance from the operative position of the cutting edge. The handle is then lowered to the operative position and the cutting edge enters the mat and slices through it to the cutting position. The mat is then pulled against the knife, sliding along the guide edge to a measured distance from the bottom of the mat. The 3 angle of inclination relative to the cut edge also facilitates pulling of the mat since I have found that if there is no such angle of inclination, the border being formed becomes jammed between the knife edge and the guide edge, and it makes the pulling of the mat very difficult, resulting in forced and uneven inner edges.
The apparatus may also include an extension located outwardly of the cutting edge with an adjustable pivot point for cutting circular beveled edges in such mats.
Other features and advantages of the present invention will be apparent to persons skilled in the art from the following detailed description of a preferred em bodiment accompanied by the attached drawing wherein identical reference numerals will refer to like parts in the various views.
THE DRAWING FIG. 1 is a plan view of a mat cutter constructed according to the present invention;
FIG. 2 is a front elevational fragmentary view, partially broken away, of the device of FIG. 1;
FIG. 3 is a close up cross sectional view showing the knife mounting, taken through the sight line 3-3 of FIG. 2;
FIG. 4 is a plan fragmentary view, partially broken away, of a modification of the device of FIG. 1 for cutting circular borders', and
FIG. 5 is a vertical cross-sectional view of the mat mounting of FIG. 4 taken through the sight line 55 thereof.
DETAILED DESCRIPTION Referring firstto FIG. 1, reference numeral 10 generally designates a flat board which is adapted to rest on a table top or other flat surface, and it provides a bed on which a mat is rested (see the outline of a fragment of a mat defined by the chain line 11). On either side of the bed 10 there are provided elongated slots 12 for receiving winged thumb screws 13 (see also FIG. 2). The lower portion of the slots 12 are enlarged as at 14 to receive corresponding nuts 15 into which the thumb screws 13 are threaded.
The shafts of the thumb screws 13 are also received in suitable apertures 17 of an elongated guide member 18. The guide member 18 includes a baseguide portion 19 and an overhanging member 20 which extends over the guide edge 21 of the base guide member 19, asseen best in FIG. 3. The base guide member 19 rests on the upper surface of the bed 10, and the entire guide member 18 may be adjusted in a fore and aft direction by loosening the wing screws 13 and adjusting them within the slots 12.
First'and second rulers 23 are provided at the edges of the bed 10, and they extend in a fore and aft direction. The function of the side rulers 23 is to provide a measured alignment between the cutting edge 21 and the cutting position of a knife designated 25. As the guide member is moved rearwardly (upward in the plane of the page in FIG. 1), the border 11a of the mat 11 will increase correspondingly as the position of the knife 25 is fixed. As will be explained in more detail below, to provide an elongated cut in the mat 11, the mat 11 is pulled relative to the knife 25,. so that the provision of dual side measuring means 23 facilitates alignment of the far edges of the guide member 18 and thus insures a border of uniform width.
Still referringto FIG. 1, an elongated block 27 is mounted by means of screws 28 to the bed 10. The block 27 extends from a rear portion of the base 10 to the forward portion, and it provides a cantilever mount for the knife 25. That is to say, the portion of the block 27 which is forward of the dashed line 29 is raised above the upper surface of the bed 10, as illustrated by the space 31 in FIG. 3. This mounting may be accomplished by inserting spacer material of suitable height between the bed 10 and the bottom of the block 27 at a position rearward of the dashed line 29. t
The forward edge or face of the blcok 27 is designated by reference numeral 32 in FIG. 1, and it is inclined at an angle of 45 relative to the horizontal so that the cut edge in the mat 11 will be inclined at a corresponding angle. Further, however, the plane of the face 32 forms a small angle, designated 33, with a line parallel to the guide edge 21. The functions of this angle will be described in more detail below, but it is noted that the angle is preferably about 3, and that it is fairly critical in the sense that if it is much below 2 or above 4, operation of the apparatus is noticeably more difficult.
A metallic cover plate 34 is secured by means of screws 35 to the inclined face 32 of the cantilevered portion of a block 27. A knife assembly generally designated by reference numeral 36 is secured by means of screws 37 to the metallic cover plate 34. The knife assembly 36 includes inner and outer metal slide plates 38 and 39 between which is sandwiched a flat knife handle 40 provided with an end finger grip 41. The lower end of the knife handle 40 is formed to a reduced thickness, as at 43 in FIG. 3 sufficient to receive a thin knife blade or razor 25. A
The lower portion 43 of the knife handle 40 is slidably received on an expanded center portion of a pin or shaft 45 which extends through suitable apertures in the slide plates 38, 39 of the knife assembly so that the handle 40 may be rotated between the operative or cutting position shown in solid in FIGS. 1-3 and an inoperative or set up position (shown in dashed line in FIG. 2) in which the cutting edge 46 of the blade 25 is raised above the upper surface of the bed to permit the placement and removal of the mat 11 without Cutting it. It will be observed that the cover plate 39 has a lower section of increased thickness as at 47 to compensate for the reduced lower portion 43 at the handle 40 so as to provide a space equal to the thickness of the blade 25. Thus, the lower portions of the plates 38, 39 serve to guide and steady the blade 25 in its operative or cutting position. i
The outer plate 39 is secured to the plate 38 be means of knurled screws 48 which permit adjustment of the frictional engagement of the blade and handle by these plates. The adjustment is made so that the handle may be selectively moved between the set up and cutting positions, yet once it is located in the cutting position, the movement of the mat against the cutting edge will not rotate the knife out of the cutting position. There is also provided astop mechanism for limiting the clockwise rotation of the knife handle 40 to the cutting position so that the lower edge of the blade 25, designated by reference numeral 50 in FIG. 2, extends slightly below the upper surface of the bed 10 into a recess 51 provided in the bed beneath the blade 25. Preferably, the blade extends to a depth of approximately one-sixteenth in. beneath the upper surface of the bed 10 on which the that 11 rests. This stop may be provided by location of the shaft of the nut 48, or a separate projection may be provided on the lower surface of the outer plate 39. A second stop is provided as seen at 52 in F IG. 2 to limit counterclockwise rotation of the knife to the set up position.
Additional measuring means or rules 58, 59 are provided adjacent the front edge of the bed 10, and it will be observed that the length designations read outwardly from the center. That is, the ruler 58 reads left to right whereas the ruler 59 reads right to left.
Turning now to the embodiments of FIGS. 4 and 5, there is shown a modification which adapts the invention to the cutting of a circular border, although the outer periphery of the mat need not necessarily be circular. That is, the outer periphery of the mat could be square or rectangular, so that the inner beveled edge alone is circular.
In FIG. 4, the mat is designated by reference numeral 60, and those elements which are similar to the ones already described bear like reference numerals. Hence, block 27 is secured to a bed 10 to provide a cantilever mount for the knife assembly 36. Again, the knife blade is secured to a handle 40 which may be selectively lowered to a cutting position or raised to a non-cutting position. Extending outwardly of a front of the base 10 is an extension 61, the center of which is formed into an elongated slot 62 extending directly outwardly of the cutting location. A pin assembly generally designated 63 is adjustably received in the slot 62; and it includes a vertical pin 64 adapted to be placed in the center of the mat 60. The pin 64 is adjustable in the slot 62 by means of thumb screw 65 which is received in a corresponding nut 67 located in a recess 68 in the surface of the extension member 61.
A measuring rule 69 is placed alongside the slot 62 to measure the radius of the inner circle being cut that is, it indicates the distance between the center of the pin 64 and the cutting location of the knife.
OPERATION In cutting a rectangular or square border from a-corresponding mat, the apparatus as illustrated in FIGS. 1-3 is used. First, with the knife handle raised to the set up position shown in dashed line in FIG. 2, the guide means 18 is adjusted using the side measuring ruies 23 to provide a border of desired width. The distance between the guide edge 21 and the upper or cutting position of the blade 25, of course, defines the width of the border 11a, and it will be realized that it is a simple matter to provide a border having different side widths than upper and lower widths. Other variations are possible.
After the guide member is properly located, the wing screws 13 are tightened to secure it in place. It will be appreciated that the cantilever mount for the knife assembly permits a user to slide the guide member. beneath it in adjusting the width of a border.
Next, the mat 1 1 is placed in position, and the leading edge of the mat, designated 11b in FIG. 1 is placed at the measured location on the right hand rule 58 as determined by the desired width of the top border. It will be observed that the right rule 58 is spaced slightly toward the right of the actual cutting position, and this is to allow placing of the cutting blade into its operative position without cutting intothe border.
As already mentioned, the plane of the face 32 is inclined at a 45 angle relative to the horizontal, and this provides for a beveled cut edge in the border, as is desirable for aesthetic reasons. In addition, however, there is the 3 angle of inclination as indicated by the arrow 33. There is a dual function to this inclination. The first function is to reduce the frictional engager'nentof the cut border between the guide edge 21 and the knife blade 25. By having the trailing edge of the knife blade located outwardly from the guide edge 21, there is reduced frictional engagement with the cut border 11a, andthe cut center portion is raised slightly upward and over the blade 25, there being no binding here. The second function of the slight 3 inclination of the plane of the cutting blade relates to a discovery which i have made, and it is that this particular inclination compensates for the required entry of the cutting blade into its operative position. That is to say, when the cutting blade 25 is rotated to its operative position it slices through the mat, but the location of entry for the leading edge in the upper surface of the mat is obviously different than itsfinal location because of the 45 beveled inclination already mentioned. It appears to me that the 3 longitudinal inclination of the face plate for the cantilever mount compensates for this rotational placement of the knife at the 45 angle and causes the knife to enter at a location almost exactly equal to that which it will ultimately assume in the operative or cutting position to achieve very clean beveled edges at the corners of the border which has heretofore provedto be quite difficult.
in continuing the operation, the matis pulled to the right until the trailing edge of the matdesignated 11d reaches the appropriate measured location on the rule 59 to provide the proper lower border. The mat is then turned around so that one of the other edges engages the guide edge 21,'and the operation is repeated.
For cutting beveled edges in a circular locus, the embodiment of FIG. 4 is used or in the center of the mat is located and the pin 64 place through it. The knife is then moved by means of the handle 40 to its operative position, and the mat 60 is rotated clockwise in a direction of the arrow 60a of FIG. 4.
Having thus described in detail preferred embodiments of my invention, persons skilled in the art will be able to modify certain of the structure which has been illustrated and to substitute equivalent elements for those disclosed while continuing to practice the principle of the invention; and it is, therefore, intended to cover all such modifications and substitutions as they are embraced within the spirit and scope of the appended claims.
1. Apparatus for cutting mats to form continuous borders comprising: base means providing a flat bed for supporting a mat to be cut; a knife assembly including a knife blade moveable between an operative and an inoperative position; adjustable means on said bed and providing a guide edge for a mat being cut; cantilever means for mounting said knife assembly spaced above said bed and for holding said knife blade at an angle of approximately 45 relative to the upper surface of said bed and at an inclination of about 3 relative to said guide edge; whereby when a mat is placed beneath said knife and engaging said guide edge, and said knife is placed in the cutting position, the cutting edge of said knife will slice through said mat to the cutting position, the knife forming a beveled cut in said mat as the mat is pulled beneath the knife guided by said guide edge.
2. The apparatus of claim 1 wherein said adjustable guide means includes a pair of elongated slots, one located on each side of said knife assembly; a guide bar providing said guide edge and extending transversely of said slots behind said knife assembly; and releaseable lock means for securing said guide bar to said slots in a fixed location.
3. The apparatus of claim 2 further comprising rule means extending perpendicular to the direction of intended cut for measuring the difference between the cutting edge and said guide edge of said adjustable guide means to define the width of a cut border.
4. The apparatus of claim 1 wherein said knife assembly includes a flat knife blade; a handle receiving said knife blade; and means for rotatably mounting said handle and knife blade to said cantilever mounting means.
5. The apparatus of claim 1 wherein said cantilever mounting means includes an elongated block spaced above the upper surface of said bed and including an inclined face, said face being inclined relative to the horizontal and approximately a 45 angle and inclined relative to the direction of intended cut at an angle of approximately 3, said last named angle opening downstream of a cut whereby the trailing edge of the cutting knife is located further away from said guiding edge than is the leading edge thereof.
6. The apparatus of claim 5 wherein said knife assembly includes first and second mounting plates; 21 flat handle rotatably mounted between said mounting plates; a flat knife blade secured to said handle; and means for securing said mounting plates to the face of said cantilever block.
7. The apparatus of claim 1 further comprising an extension of said base outwardly'of said knife assembly and including pivotal mounting means for securing a mat thereto, whereby a beveled edge may be cut in said mat by rotating the same about said pivotal mounting means.
8. Cutting apparatus for cutting; a beveled edge in a mat comprising: a base providing a flat surface for slidably supporting a mat; cantilever mounting means secured above said flat surface; a guide edge secured to said base beneath said cantilever mounting means at a predetermined distance from a cutting area; a cutting blade rotatably mounted to said cantilever mounting means above said cutting area and selectively moveable by an operator between an inoperative position and an operative cutting position at which the lower edge of said knife extends slightly beneath the upper edge of said flat surface, said base defining a recess to receive said blade in the operative position; guide means for engaging a mat on said base while permitting sliding thereof and receiving said mat beneath said cantilever means at a distance equal to a desired width for said border; said knife being mounted at an inclination relative to the horizontal and at a slight inclination of about 3 relative to the intended direction of cutting, the trailing edge of said knife blade being located further from the outer peripheral edge of said :mat than the cutting edge as said mat is moved to effect a cut.
9. The apparatus of claim 8 wherein said guide edge is a straight edge and wherein said guide means is adjustably mounted to said base, said apparatus further including measuring means for measuring the distance between said cutting location and said guide edge to define said border.
10. The apparatus of claim 8 further comprising second and third rule means extending respectively outwardly of said cutting location and parallel to said guide edge, second and third rule means being located to measure the beginning and end of a cut so as to prevent cutting into the border areas extending orthogonal to a given cut.