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US-12623366-B2 - Cutting guide for cutting fibrous or thick sheet materials

US12623366B2US 12623366 B2US12623366 B2US 12623366B2US-12623366-B2

Abstract

A cutting guide for laying out, squaring and facilitating the cutting of fibrous batt insulation materials used in building construction is described. The cutting guide permits the substantially uniform compression of underlying materials and provides a straight edge along which a knife can be slid to uniformly cut the underlying material. A handle is provided to facilitate the even application of pressure along the guides length.

Inventors

  • Lee Hiram Stevens

Assignees

  • Lee Hiram Stevens

Dates

Publication Date
20260512
Application Date
20251208

Claims (19)

  1. 1 . A cutting guide for use with a knife for cutting fibrous and/or thick sheet materials, the guide comprising: a rectangular body having a generally horizontally-disposed top side intersecting with left and right longitudinal sides that extend downwardly from the top side at a side angle of at least 30 degrees and terminate in respective left and right longitudinal bottom edges, the rectangular body having first rule markings on its top surface proximate one or both the left and right longitudinal sides; and a grip rail assembly comprising a grip rail elevated above the rectangular body by a two or more of elevating spacers attached to the grip rail and the rectangular body, the grip rail being configured to be held in a hand of a person and being substantially parallel to the right longitudinal side.
  2. 2 . The cutting guide of claim 1 , wherein the rectangular body is in the form of a rectangular frame having an open interior framed by the top side.
  3. 3 . The cutting guide of claim 2 , wherein the top side intersects with opposing first and second lateral sides that extend downwardly from the top side at angle and terminate in respective first and second lateral bottom edges, ends of the first and second lateral sides intersecting with ends of the left and right longitudinal sides.
  4. 4 . The cutting guide of claim 3 , wherein the rectangular body has second rule markings on its top surface proximate the first and second lateral sides.
  5. 5 . The cutting guide of claim 2 , wherein the elevating spacers comprise a plurality of struts, the struts attached to and extending upwardly from the rectangular frame on first strut ends and being attached to the grip rail at second strut ends.
  6. 6 . The cutting guide of claim 1 , wherein the rectangular body is in the form of a u-shaped straightedge body with the left and right longitudinal sides extending substantially orthogonally downwardly from respective intersections with the top side.
  7. 7 . The cutting guide of claim 6 , wherein the straightedge body has a straightedge length of at least 36 inches and a straightedge width of about 3.5 to 5 inches, and the left and right longitudinal sides each have a side width of at least 0.50″.
  8. 8 . The cutting guide of claim 7 wherein the straightedge length is about 48″ and the straightedge width is about 4″.
  9. 9 . The cutting guide of claim 6 , wherein the elevating spacers comprise at least first and second elevating blocks that support a bottommost portion of the grip rail above the top side at least 0.75″, and a rightmost portion of the grip rail is spaced about at least 1.75″ from the right longitudinal edge.
  10. 10 . The cutting guide of claim 9 , wherein the grip rail assembly is centered longitudinally on the rectangular body with the first and second elevating blocks being spaced apart a distance of about 60% of a longitudinal length of the rectangular body.
  11. 11 . The cutting guide of claim 1 , wherein at least the right longitudinal bottom edge comprises an inwardly facing bevel.
  12. 12 . The cutting guide of claim 11 , further comprising a non-skid insert and/or element attached to the left longitudinal side.
  13. 13 . The cutting guide of claim 1 , wherein the grip rail is positioned laterally closer to one of the right and left longitudinal sides relative to the other of the right and left longitudinal sides.
  14. 14 . The cutting guide of claim 1 , wherein the grip rail is generally cylindrical or ovular and has an effective diameter of about 1-2 inches.
  15. 15 . The cutting guide of claim 1 , wherein the grip rail includes a cushioning element comprising an outside surface of the grip rail.
  16. 16 . In combination, the cutting guide of claim 1 and a knife, the knife comprising: a blade having an elongated substantially linear blade edge and defining a blade plane; and a knife grip coupled with the blade, the grip having a grip longitudinal length, a grip leading edge located in the blade plane, a grip top end and a grip bottom end, and defining a grip line and a grip intersection point; wherein an intersection angle made between a projection line defined by the blade edge and the blade line is between 70 and 89 degrees with the blade line being canted rearwardly, and the grip intersection point occurs at a location at or below a center point of the grip line.
  17. 17 . A method of using the combination of claim 16 to cut a fibrous batt, the method comprising: placing the cutting guide against the fibrous batt and aligning the right longitudinal edge with a desired cutline; while holding the cutting guide at the grip rail with one hand, compressing the fibrous batt at the cutline by applying downwardly pressure to the cutting guide through the grip rail; while holding the knife by the knife grip in another hand, positioning the knife blade against an edge of the fibrous batt along the right longitudinal side with the angle between the blade edge and a top surface of the fibrous batt being about 35 degrees; and pulling the knife through the fibrous batt to cut it.
  18. 18 . The cutting guide of claim 1 wherein: the rectangular body in the form of a u-shaped straightedge body having a straightedge length of about 48″ and a straightedge width of about 4″ with the left and right longitudinal sides extending substantially orthogonally downwardly from respective intersections with the top side with each side having a width of at least 0.50″; the right longitudinal bottom edge comprises an inwardly facing bevel; the elevating spacers comprise at least first and second elevating blocks that support a bottommost portion of the grip rail above the top side at least 0.75″, and a rightmost portion of the grip rail is spaced about at least 1.75″ from the right longitudinal side; the grip rail assembly is centered longitudinally on the rectangular body with the first and second elevating blocks being spaced apart a distance of about 60% of a longitudinal length of the rectangular body; and the cutting guide further comprises a non-skid elastomeric and/or rubber non-skid insert and/or element attached to the left longitudinal side.
  19. 19 . The cutting guide of claim 1 wherein: the rectangular body is in the form of a rectangular frame having an open interior framed by the top side; the top side intersects with opposing first and second lateral sides that extend downwardly from the top side at angle and terminate in respective first and second lateral bottom edges, ends of the first and second lateral sides intersecting with ends of the left and right longitudinal sides; the rectangular body has additional rule markings on its top surface proximate the first and second lateral sides; at least the right and left longitudinal bottom edges each comprise an inwardly facing bevel; the elevating spacers comprise a plurality of struts, the struts attached to and extending upwardly from the rectangular frame on first strut ends and being attached to the grip rail at second strut ends; and the grip rail is positioned laterally closer to one of the right and left longitudinal sides relative to the other of the right and left longitudinal sides.

Description

RELATED APPLICATIONS This application claims the benefit of and hereby incorporates by reference U.S. patent application Ser. No. 17/974,705 filed Oct. 27, 2022 entitled Knife and Cutting Guide for Cutting Fibrous or Thick Sheet Materials, which claims the benefit and incorporates by reference two U.S. Provisional Patent Applications each having the same inventor as the present application: namely, application No. 63/278,662 filed on Nov. 12, 2021 and having the title “Insulation Knife” and application No. 63/278,654 filed on Nov. 12, 2021 and having the title “Batt Cutting Guide”. BACKGROUND Energy costs and codes have created a heightened awareness of insulation products and performance. Mineral wool batt-type insulating products are increasingly being used over conventional fiberglass batting, as are various foam board insulations. While the cutting of conventional fiberglass batting can be challenging and put undue strain on an installer's hands and wrists, both these alternative insulating materials are harder to cut with the conventional prior art knives used by most insulation installers. Cutting any type of insulation product with a knife involves angling the blade into the material, and drawing the blade through the material, towards the user's body. Conventional prior art knives typically have a blade on axis or generally parallel with the handle, which requires the user to flex the wrist at an extreme angle in order to align the blade into the cut to be made. This puts a significant strain on the wrist, before even starting the cutting action. The pull force is directed along the axis of the handle or grip, so that the user must squeeze tightly to maintain a grip on the handle, and prevent the hand from sliding lengthwise off of the handle, while pulling through the cut. It is not uncommon to see insulation installers hold a fiberglass batt up against a wall stud, and draw the knife downwardly. The knuckles are thereby arranged nearly vertically and the wrist is relatively relaxed, but the gripping action must still be forceful, to prevent the hand from slipping along the axis of the knife handle. Ergonomic knives have been introduced, in which the cutting edge emanates from the bottom of a grip whose longitudinal axis (or grip line) is angled top forward, relative to the cutting edge. For cutting thicker materials, this requires a significant forward flex of the wrist to engage the blade to the full depth required. This rotational force results in excessive wrist strain while in use cutting thicker materials. Insulation saws have been devised, particularly for cutting mineral wool batts and foam board. The grips are typical of handsaws, in that the grips are located above the cutting edge of the blade, and canted forward at an acute angle of about 60 degrees to the blade edge. On the pull stroke, the user's grip is more or less square to the direction of force applied. This means that the fingers can curl around the front side of the grip or handle, and the pull force is taken at the first knuckles of all four fingers together. The total force applied is only the pull force, and does not require an extra squeezing or compression force to keep the hand from sliding in the direction of the pull. Sawing requires extra time and energy, to repeatedly move the arm back and forth. A law of physics states that energy expended is proportional to surface area created, and the foam sawdust particles generate a far greater surface area than a knife cutting cleanly through the same material. Another liability is that the insulation particles created by the saw cutting process may also be both a nuisance and unhealthy to breathe. To efficiently cut lofted fibrous batt insulation, such as fiberglass and mineral wool, they must be compressed or otherwise restrained while cutting. This allows the knife blade to cut through the fibers, as opposed to snagging, dragging and clumping the fibers. The thicker the batt, the greater the problem, and the greater the need to compress the fibers to enable an efficient cut to be made. It is common in the trades to compress the batt with the fingers, and hand pressure. This exposes the fingertips to inadvertent cuts, and is also slow, due to the hand having to be re-positioned every few inches of cut. Further this method often does not lend itself to accurate cutting. Minerals wools, which are becoming increasingly popular, will not easily fluff to fill gaps making accurate cutting even more imperative. Some insulation installers have been known to use tee squares that are very commonly used by drywall installers. However, tee squares have disadvantages for use in cutting batt insulation. The tee head interferes with starting the long knife blade required for the deep cuts, and a typical 48 inch rule edge is too long and therefore unwieldy even for the longest, most common crosscut, on 23 inch wide batts. Trying to compress the batt fibers by pressing down on a long flat, sl