US 2908972 A
Description (OCR text may contain errors)
CL 20, 1959 NlTENsQN l 2,908,972
ARTIST'S KNIFEl Filed July 51, 1956 IIIIIII III United States Patent C) 2,908,972 p Y Aurrsrs KNrFE -Edward Nitenson, Sharon, Mass. v i "Application July 31, 1956, Serial No. 601,208 i 6 claims. (cl. sti- 293) v' Ihis invention relates to cutting tools and more particularly comprises a new and improved precision cutting tool .of the type used by artists and draftsmen.
One mportantobject of my invention is to provide a cutting tool having a blade which may be set at any desired distance beneath the bottom of the frame which holds it.
Another important object of my invention is to provide a regulator or adjustment for the blade which may easily be operated manually.
Still another important object of my invention is to provide a cutting instrument which may easily be guided along a straight edge.
Yet another important object of my invention is to provide a cutting tool which may be used with equal ease by both left-handed and right-handed persons To accomplish these and other objects of my invention my precision cutting tool includes, among its several features, a frame having a vertical slotted region extending across its bottom and terminating short of the top of the'frame. Extending across the frame and through the slotted region are drilled'holes adapted to receive a pin which pivotally supports the cutting blade. The cutting blade which may be a standard Exacto blade may be selectively pivoted at either of the holes.
Two additional holes are drilled vertically in the frame with their axes coincident with the center of the slotted region. A spring is disposed in the bottom of one of the additional holes and bears against the lower or cutting edge of the blade, while a screw having a knurled head is threaded into the top of -that hole and bears against the top edge of the blade. By tightening the screw in the hole, the blade is lowered against the bias of the spring so that it extends a greater distance out of the slotted region and below the bottom of the frame. The screw itself provides a firm bearing surface for the blade when the instrument is in use and prevents the blade from re? `ice y description of two embodiments thereof, selected for tracting into the slotted region of theframe when pres# sure is applied-against its cutting edge.
The blade, the pin, the spring and the screw may be reversed in the frame, for duplicate holes are provided for this purpose.' This feature permits the blade to be drawn across a straight edge from either left to right or right to left, so that the tool may easily be handled b either a right-handed or left-handed person. i
In addition to the features alluded to above, the frame of my cutting tool includes a ange which cooperates with the-side of the frame to form a guide so that the tool may be drawn along a straight edge. The side edges of the frame beneath the flange are rounded so that when the tool is drawn along the straight edge, it will run smoothly and Snot gouge the straight edge. Because this guide lies on but one side of the frame, it is, of course, of great advantage to have the flexibility of blade position as described in the preceding paragraph. x
Asp another feature of my invention, the precision cutpurposes of illustration and` shown in the accompanying drawing wherein:
Figure l is a frontv elevation view of a precision cutter constructed in accordance with my invention', pp
Figure 2 is a cross-sectional View taken alongthe corresponding section lines of Figure 3, v
Figures 3 and 4 are cross-sectional viewstaken along the corresponding section lines of Figure 2,
Figure 5 is a partial cross-sectional view taken alongV the corresponding section lines of Figure 1, and,
Figure 6 is a View similar to that of Figure 2 and illustrating a slightly modiled frame. .t The embodiment of my invention illustrated in Figures l-5 includes a frame 10 having a vertical slot 12 extending across its entire width and a cutting blade 14. y
The frame 10 is rectangular in cross section (see Figure 2) and has a pair of parallel legs 16 which define the sides of the slot12. A pair of parallel holes or openings lfextendthrough the legs 16 and normal tothe slot 1,2, one end of each of the holes being counter-sunk; while their other ends are threaded. Either of the holes may receive a screw 20V which extends across the slot v12 and through the opening 22 formedin the blade 14.
From the foregoing description, it will be Vapparent that the blade 14 may be mounted either inthe position shown in Figure 2er alternatively on the opposite side of the frame 10 by threading the screw 20 into the other hole 18 provided in the frame. The reasons for this will be more fully explained in the following paragraphs.
A pair of recesses 24 and 26 are formed vertically in the frame 10, one on the outside of each of the holes 18. The axes of the recesses 24 and'26 are coincident with the` center of the slot 12. This feature is clearly`shown in- Figure 4. The recesses 24 and 26 areA somewljatrwiderk than the width; of the slot 12 and thus are capable 'of supporting a spring 28 at their bottoms.'v The spring 28,' shown at the bottom of recess 24 in Figures 2 and 4, bears against the lower cutting edge 30 of the blade 14 and. urges the blade upwardly in the s1otf12 in a clockwise. direction aboutthepivotal support pin 20. A screwfv32v having a knurled head 34 is threaded into the recess 24.` and its lower end abuts against the'upper edge 36 ofthe blade 14. The recess 24 is, of course, threaded to receive the screw 32, these threads extending downwardly from the top of the frame 10 to the slot`r12. These threads may, of course, extend downwardly to Vthe bottom of the recess; but this is unnecessary. From the foregoing description, it will be appreciated that by tightening the screw 32 into the frame 10, the blade 14 is forced downwardly by the bottom of the screw` against the bias of the spring 28 so that it assumes a lower position in the slot 12; that is, the blade assumes a greaterV angle with the horizontal, thus moving its end 38 a greater distance belorwlthe bottom of the frame.` In this manner, the screw 32 provides a precision adjustment for the blade 14 so that the exact depth of the cut made by the blade may be selected-readily. It will be noted also that the bottom of the screwV 32 which bears against the upper edge 36 of the blade 14 provides a solid bearing surface for the blade and will not permit it to move upwardly lwhen pressure is applied `to the cutting edge 30 as the Vtool is used. The spring 28 constantly urges the blade against the bottom of the screw and assures the operatorthat then blade is 'positioned at the depth selected. The
" lcnurled head 34 of the screw affords the user'a ready Y 3 means of quickly adjusting the cutting depth of the blade without the need of additional tools.
A ange 40 carried on the side of the frame 10 cooperates with the side wall 42 of the frame to form a lguide for drawing the instrument along a straight edge. When a cut is to be made with the aid of a triangle, T square, or other straight-edged instrument, the flange 40 rides on the upper surface of that instrument while the side wall 42 rides along the edge of the instrument to guide the tool along a straight line. The iiange 40 actually controls the depth of the cut made by the knife or blade 14, while the surface 42 of the side of the frame vguides the tool along a straight line.
It will be noted in Figure 5 that the edges 44 of the side wall 42 are rounded. The rounded edges prevent gouging of the straight edge when the tool is drawn along it. The radius of the edges 44, of course, must be rather small so as not to introduce any tendency for the tool to rock on the edge.
The importance of being able to mount the blade either in the position shown in Figure 2 or alternatively in the reverse position with the blade extending tothe lower right corner of the frame may now be fully appreciated. It is natural for a right-handed person to draw a tool of this kind from left to right across the straight edge of a square, triangle or other similar guide. However, it is extremely awkward for a left-handed person to do this. With the blade mounted as shown in Figure 2, a right-handed person may use the instrument naturally; that is, he can draw the blade across the straight edge from left to right. A left-handed person who naturally draws an instrument of this kind from right to left would ind it desirable to shift the position of the blade 14 so that it extends downwardly and to the right as viewed in Figure 2. The second hole 18 and the recess 26 are provided so that this change may be made quickly and without diiiiculty. To accomplish this reversal of parts, the pin 20, the spring 28, the screw 32 and the blade 14 are first removed from the frame. Then the user merely drops the spring 28 into the recess 26 from the top of the frame 10, next slides the end of the blade 14 into the slot 12, which will be turned over from the position shown in Figure 2, and aligns the hole 22 in the blade with the second hole or opening 18. Next, the screw is threaded into the hole 18, and the screw 32 is turned into the recess 26. By this very simple operation, the blade is positioned for comfortable use by a left-handed person. The cutting edge 30 of the blade 14 will face downwardly and in a position to be drawn from right to left across a straight edge.
As shown, the end 38 of the blade 14 extends beyond lthe end ofthe frame 10. This is true whether the blade is mounted in the position illustrated or in the reverse positionpsuitable for left-handed users. This allows the end of the blade '58 to be seen by the user and thus permits him to align the blade with a prescribed cutting line. If
, 4 4 the pivotal action of the blade. Of course, other means could be used to accomplish the same purpose.
The instrument that I have invented is very easy to use and is well balanced so that it will easily ride along a straight edge without wobbling or tilting. The major portion of the Weight of the instrument lies on the side of the blade nearer to the flange 40. Thus, the center of gravity of the instrument will be disposed above the surface of the straight-edge instrument; and it will have no tendency to tilt outwardly away from the straight edge. As a result, the blade 14 will maintain its vertical alignment, and a square edge will be provided the material which is eut by it. Because it is desirable to have the instrument centered in this fashion, the guide for moving the instrument along a straight edge is confined to but one side of the frame 10. This, of course, ycreates the need for providing means for shifting the position of the blade 14 to suit both left-handed and right-handed users.
In view of the fact that numerous modifications may be made of my invention, I do not intend to limit its scope to the specific embodiment illustrated and described; rather it is my intention that the breadth be determined by the `appended claims and their equivalents.
What I claim as new and desire to secure by Letters Patent of the United States is:
l. A device of the character described comprising an elongated frame, said frame having means defining an upwardly extending slotted region longitudinally in the bottom of the frame and elongated so that the slotted region extends to the ends of the frame, a pair of spaced apait downwardly extending threaded recesses formed in the top of the frame intermediate its ends and intersecting the slotted region, each of the recesses being wider than said slotted region and having their centers coincident with the center of the slotted region, a pair of spaced apart horizontal openings formed in the frame between the recesses and intersecting the slotted region, one of said openings being adjacent one recess and the other of said openings being adjacent the other recess, an elongated single edge cutting blade having 'an opening adjacent one end, a pin adapted to iit into either of the openings in the frame and through the opening in the blade and selectively support the blade in the slotted region so that it extends out either end of the slotted region and with the cutting edge facing downwardly, said blade passing through the recess adjacent the opening into which the pin is itted, a spring disposed in the bottom of that recess below the blade and bearing upwardly against the bottom of the blade biasing -the blade upwardly in the slotted region, and a screw disposed in that recess and extending downwardly to the top of the blade for moving the l blade downwardly against the bias of the spring.
the blade were completely hidden by the frame, it would be impossible for an operator to View the exact location of the blade and thus it would be extremely difficult for him to determine whether or not the blade was aligned with the line along which the cut was to be made.
The frame of the tool just described may be made of steel, or -other rigid metal. However, it is not beyond the scope. of my invention to use non-metallic material, such as plastic for it. Clearly the simple shape of the frame makes it peculiarly susceptible to molding. If a plastic material is used, it may prove necessary or desirable to add strength and rigidity to the frame. In Figure 6, a tool frame 50 has a slot 54 extending across its length as in the previous embodiment. However, thev slot is interrupted by a rib 52 which extends -between the sides of the slot 54. The `rib 52 prevents the legs forming the sides ofthe slot from spreading, but does not interfere with 2. A device as defined in claim l further characterized by a rib disposed in the slotted region between the openings and secured to the frame for strengthening the frame.
3. A device comprising a frame, a horizontal flange formed on one side of the frame and above the bottom of the frame forming a guide to draw vthe frame along a straight edge, a pair of upwardly extending slots formed in the bottom of the frame and parallel to said one side of the frame, a pair of spaced apart and downwardly extending recesses formed in the frame and one .intersecting each slot, a rib disposed between the slots and between the recesses and secured to the framefor strengthening the frame, a single edge cutting blade having an opening at one end, a pin extending through the opening in the blade and adapted to be secured to the frame between the recess 'in either slot and the rib for selectively pivotally mounting the blade in that slot so that it extends through one of they recesses with the cutting edge facing dovmwardly and with the other end of the blade extending out of that slot, a spring secured to the frame and engaging the blade urging the blade to pivot upwardly in that slot, and a screw threaded downwardly into the recess through which the blade extends for limiting the upward pivotal movement of the blade under the influence of the spring.
4. A device of the character described, comprising an elongated frame, a pair of aligned upwardly extending slots formed longitudinally in the bottom of the frame and elongated so that opposite ends of the Slots extend to the ends of the frame, a pair of spaced apart downwardly extending threaded recesses formed in the top of the frame intermediate its ends and one intersecting each of the slots, each of the recesses being wider than the slots and having their centers coincident with the `center of the slots, an elongated single edge cutting blade having an opening adjacent one end, a pin extending through the opening in the blade and adapted to be secured to the sides of either slot adjacent the recess intersecting that slot for selectively supporting the blade in the slots so that it extends out either end of the frame with the cutting edge of the blade facing downwardly, said blade passing through one of the recesses, a spring disposed in the bottom of said recess below the blade and bearing upwardly against the bottom of the blade biasing the blade upwardly in that slot, and a screw disposed in that recess and extending downwardly to the top` of the blade for `moving the blade downwardly against the bias of the spring.
5. A device as defined in claim 4, further characterized by a horizontal ange formed on one side of the frame and spaced upwardly from the bottom of the frame and forming with the lower portion of that side of the frame, a g-uide for drawing the frame along a straight edge.
6. A device comprising a frame, a horizontal ange formed on one side of the frame and above the bottom of the frame forming a guide to draw the frame along a straight edge, said frame having means dening an upwardly extending slotted region in the bottom of the frame and parallel to said one side of the frame, a pair of spaced apart and downwardly extending recesses formed in the frame and intersecting the slotted region, a single edge cutting blade having an opening at one end, a pin extending through the opening in the blade and adapted to be secured to the frame between the recesses for selectively pivotally mounting the blade so that it extends through either one of the recesses with the cutting edge facing downwardly and with the other end of the blade extending out of the slotted region, a spring secured to the frame and engaging the blade urging the blade to pivot upwardly in the slotted region, and `a screw threaded downwardly into the recess through which the blade extends for limiting the upward pivotal movement of the blade under the influence of the spring.
References Cited in the tile of this patent UNITED STATES PATENTS 262,218 Geiger Aug. 8, 1882 1,475,264 Gundlaeh NOV. 27, 1923 1,737,552 Altman et al. Dec. 3, 1929 2,282,062 Jewett May 5, 1942 V2,685,764 vInl-Ipateld Aug. 10, 1,954