US 3918158 A
A specialty knife is described which is particularly suitable for cutting linoleum, asphalt, vinyl and the like flexible floor tile, shingles, etc., wherein the knife is of the conventional hooked, concave-convex linoleum knife shape including a sharpened point for the scribing of a cutting or breaking line on the material to be cut. In addition, there is provided a double-bladed angled cutting edge on the forward side of the convex portion of the knife so as to provide cutting surfaces designed for the forward pushing of the knife forward through the material being cut. As an added feature, a similar double-bladed cutting edge can alternatively be provided in a mirror relationship to the forward cutting blade so as to provide controlled cutting of the knife through the material being severed when drawing the knife toward the operator.
Description (OCR text may contain errors)
Unlted States Patent 1191  3,9
Debski Nov. 11, 1975 1 SPECIALTY KNIFE  Inventor, Joseph L Debski, P'Q BOX 427 Primary E.\'aminerA1 Lawrence Smith Lenoir NC 28645 Assistant E.\a/71iner-.1. T. Zatarga Attorney, Agent, or Firm1-1erbert M. Adrian, Jr.  Filed: June 13, 1974  Appl. No.: 478,862  ABSTRACT A specialty knife is described which is particularly [52 US. Cl. 30/314; 30/315; 30/317 Suitable for Cutting linoleum, asphalt, vinyl and the 511 1111. C1. B26B 3/08 like flexible floor tile, Shirrgles, Wherei the knife  Field of Search 30/294, 314, 317, 315 is of the Conventional hooked, Concave-Convex linoleum knife shape including a sharpened point for the [5 References Cited scribing of a cutting or breaking line on the material UNITED STATES PATENTS to be cut. In addition, there is provided a double- 73 497 7 bladed angled cuttingedge on the forward side of the 5342 4 at??? ii convex portion of the knife so as to provide cutting 3 2 10/1897 s z i 30/314 X surfaces designed for the forward pushing of the knife 5411963 7/189; car emijj1:31...33i::311:11:11.... 30/294 fdrwdrd rhrddgh drd rrrdrdrrdl bdrrrg As an added 1,516,789 11/1924 Rassner 30/314 featurer Similar doublebladed cuttirg edge can 1390,0121 1/1931 H 30/294 X ternatively be provided in a mirror relationship to the 1,843,223 2/1932 Hasseler 30/314 X forward cutting blade so as to provide controlled cut- 1,988,386 1/1935 Komperud 30/314 ting of the knife through the material being severed 3.605.268 9/1971 Cassell 30/294 when drawing the knife toward the perat r, Dl28,623 8/1941 Dorcas 30/317 UX 0208.990 10/1967 Anderson et a1 30/314 UX 3 Claims, 2 Drawing Figures US. Patent Nov. 11, 1975 SPECIALTY KNIFE BACKGROUND OF THE INVENTION normally cut by such knives, several passes of the knife are required, or the material is merely broken at the scribe line. It is frequently most difficult to utilize more than the cutting point of the knife to complete the cut because the concave shape tends to feed the material to the sharpened point rather than maintaining it on the broader cutting edge.
It is an object of the present invention to provide a knife for the cutting of linoleum, asphalt tile, vinyl tile, roofing material and the like pliable material which enables the operator to more completely sever the material in an easier, surer manner.
It is a further object of the present invention to provide a cutting knife which can be operated in either the pushing or the drawing direction.
It is yet another object of the present invention to provide a hand operated knife which has versatile utility in severing numerous types of pliable sheet material in a single pushing or drawing motion.
These and other objects of the present invention will become more apparent from the description of the invention which follows.
THE INVENTION In accordance with the invention, a specialty knife is provided which is particularly suitable for cutting linoleum and pliable sheet material wherein said knife has a curved blade having a concave and a convex side, said concave side having a cutting edge terminating in a pointed end at the junction with the convex side, the improvement comprising said convex side having an angled, double-bladed cutting edge on the forward side of said convex side positioned at about the area of lowest radius of curvature to thereby position said doublebladed cutting edge for operation by forward pushing of said knife, said angled blades forming an open angle of 20 to 65.
As an optional improvement to said knife, a second angled double-bladed cutting edge is provided in mirror relationship to said forward facing double-bladed cutting edge, said second blade being positioned closer to the handle of said knife and positioned for operation by drawing said knife toward the operator, said angled blades forming an open angle of 20 to 65.
DETAILS OF THE INVENTION The invention will be more fully described by reference to the drawings in which:
FIG. 1 is plan view of the knife of the present invention; and,
FIG. 2 is a plan view of a further embodiment of the knife of the present invention.
Referring more particularly to FIG. 1, knife blade comprises a lower concave edge 14 and an upper concave surface having angled cutting blades 15 and 16 positioned therein. Knife blade 10 is conveniently uti- 2 lized with handle 22 which can be of the desired shape and design. Concave edge 14 is sharpened along its length terminating at the point of junction with the upper convex surface.
The sharpened angled blades 15 and 16 are positioned in the convex surface of the blade in the forward direction thereof, preferably at about the location where the convex sides radius of curvature is at the smallest radius, thereby positioning the angled blade for utilization in the forward pushing direction.
Angle A between sharpened blades 15 and 16 is an acute angle of 20 to 65, and more preferably in the range of 20 to 40, with about 25 being the most preferred angle. Such an angle produces a cutting slot which retains the material being severed into a lockedin position between the sharpened blades thereby eliminating the slipping of the material being cut out of the cutting surfaces. Additionally, it is preferred that the angle be located within the convex surface such that blade 15 is approximately parallel to the axis of the handle 22 or at a small angle below the horizontal axis of the handle. In the same manner, blade 16 forms a forward angle as measured from a line perpendicular to the axis of the handle.
Referring more particularly to FIG. 2, blade 12 is similar to that described in FIG. 1 with the additional provision that angled blades 18 and 20 are provided. These double-sharpened blades form angle B which is an acute angle of 20 to 65, more preferably 20 to 40, and most preferably about 25. This angle can be independently selected or can correspond to angle A. In the same manner, it is preferred that blade 20 is on a line which passes through blade 15 or is parallel thereto. Blade 18 is angled toward the handle so as to engage and lock into the cutting blades the material being severed by the drawing of knife 12 toward the operator.
Handle 22 can be of any shape or size and attached in any suitable manner. It is preferred, however, that the handle be designed for both a drawing and a pushing operation.
While the invention has been described more particularly in accordance with applicants preferred embodiments, it is recognized that various changes may be made in the detailed construction within the spirit and scope of the present invention. It is intended however to limit the invention solely by the claims which follow.
What is claimed is:
l. A specialty knife particularly suitable for cutting linoleum and pliable sheet material, wherein said knife has a curved blade having a concave and convex side, said concave side having a cutting edge terminating in a pointed end at the junction with the convex side, the improvement comprising. said convex side having an angled double-bladed cutting edge radiating from the apex of the angle on the forward side of said convex side positioned at about the area of lowest radius of curvature thereby positioning said double-bladed cutting edge for operation by forward pushing of said knife, said convex side having a second angled doublebladed cutting edge radiating from the apex of the angle in mirror relationship to said forward facing double-bladed cutting edge, said second cutting edge being positioned closer to the handle for said knife and positioned for operation by. drawing said knife toward the operator, both of said angled blades forming open angles of 20 to 65.
2. The knife of claim 1 wherein the open angle is of 20 to 40.
3. The knife of claim 2 wherein the angle is about