CA1224386A - Hand held cutting tools - Google Patents
Hand held cutting toolsInfo
- Publication number
- CA1224386A CA1224386A CA000475107A CA475107A CA1224386A CA 1224386 A CA1224386 A CA 1224386A CA 000475107 A CA000475107 A CA 000475107A CA 475107 A CA475107 A CA 475107A CA 1224386 A CA1224386 A CA 1224386A
- Authority
- CA
- Canada
- Prior art keywords
- cutting
- blade
- teeth
- hand saw
- edge
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23D—PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR
- B23D61/00—Tools for sawing machines or sawing devices; Clamping devices for these tools
- B23D61/12—Straight saw blades; Strap saw blades
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Knives (AREA)
- Scissors And Nippers (AREA)
Abstract
Abstract of the Disclosure A hand saw having cutting teeth with a depth limiting design com-patible with the forces capable of being generated by an operator. The leading cutting edge is followed by a rearwardly sloping bottom surface that allows the operator to control the bite of the teeth and thereby produce a smoother cutting action.
Description
~3~;
~ his invell-tioll relates to cutting tools for cutting wood, e.g. for pruning outdoor trees and shrubs and for carpentry applications.
Hand held cutting tools are generally of two basic types; hand held knives and hand held saws. The basic design for the knife and saw are similar i.e. an elongated blade is provided with a handle at one end. The basic operation for both is also similar i.e., the blade is drawn back and fourth across the desired cutting line while pressure is applied on the blade by a pivotal urging of the operators wrist. The cutting ac-tion, however~ is quite different. The knife utilizes a continuous cutting edge and slices through and thereby separates the material being cut~ while the saw has teeth that individually bite into and remove bits of material thereby digging a trench or kerf as it is commonly called.
The smooth precise cutting action of a knife is highly desirable, but for many applications the knife is simply unsuitable. For example, con-sider a large tree limb. The sharp edge of the knife will easily slice into the wood but only to a very shallow depth. As the blade enters the cut, the cut has to widen. Wood is "elastically" compressable (more or less depending on the type of wood) and thus penetration is permitted simply by the sides of the blade forcing compression of the wood fibers to thereby enlarge the cut.
However, as more of the blade is forced into the cut, the cumulative effect of the resistance by the wood member to this compression vcry quickly renders it very difficult for the operator to continue cutting.
The hand held saw, having its blade edge made up of a sequence of sharp points, (referred to as teeth) cuts a trench that allows free entry of the blade. Typica]ly, the cutting action of the saw involves a drawing of the saw blade coupled with forward pivoting of the wrist to achieve penetration -- 1 -- ,, ~ .
of the tee-th. The teeth dig in and pu].l loose ;n a rapidly repetitive action, and in the process, wood particles are ripped or torn loose from the wood member. As the saw teeth are worked back and forth in the cut, the trench is increased until the desired severing of the wood member is accomplished. rihis cutting action will be herein re:Eerred to as stutter cutting.
A major problem with the sawing blade is that at least in start up, the stutter cutting ma.kes it difficult to hold the blade on the desired line of cut. This diffi.culty is re:ferred to as the saw's tendency to skate and is a major cause of minor accidents experiellced by operators placing their off hand too close to the desired line of cut. Also, the cut is ragged, the cutting efficiency is poor, and using the saw is uncomfortable and often a difficult task for the operator. These problems can be reduced by reducing the space between the teeth (depth and length) bu-t to do so limits the ability of the saw to remove the particles and this undesirably affects the saw's cut-ting capabilities.
Summar,~f~th_____~___on The present invention is directed to the achievement of a cutting saw wherein the cutting action substantia:Lly departs from that of typical stutter cutting of existing saws and approaches more closely the slicing action of a cutting knife, without materially effecting the saw's cu-tting ability.
The invention provides a hand saw for severing wood materials com-prising; a blade having a cutting edge formed by a series of cutting teeth, the spacing between the teeth forming gullets for carrying wood chips, certain of said teeth having a front surface and a bottom surface cooperatively formed for controlled depth cutting of the wood material, said front surface and bot-tom surface intersecting to form a leading cutting edge having a leading cutting point, said bottom surface being angled inwardly relative to the blade from the cutting edge wi-thin a shallow angular range to form a limiting surface whereby penetration of the cutting point into the wood material is limited to a controlled depth.
In general, the cutting teeth are designed to penetrate to a con-trolled depth and to substantially retain that depth to s:Lice away wood chips rather than tear out wood particles. This is accomplished by forming the teeth with an elongated tapered bottom relief surface that controls the depth of cut. With little or no wrist pressure, the points of the teeth are limited to a very shallow depth that is ideal for start up. As a kerf is established, increased wrist pressure achieves increased depth of penetration, bigger bites, and more rapid cutting, all while substantialLy eliminating the undesirable characteristics of stutter cutting.
Detailed Description and Drawings Having thus briefly described the invention, the preferred embodi-ment will now be described in detail with reference to the accompanying drawings, wherein:
Figure 1 is a side view of a pull type pruning saw o-f the present invention;
Figure 2 is an enlarged view of a section of the pruning saw of Figure l;
Figure 3 is a view taken on view lines 3-3 o:E Figure 2 illustrating a cutting tooth of the saw;
Figure 4 is a view taken on view lines 4-4 of Figure 3 illustrating a cutting tooth on the other side of the saw;
Figure ~ is a bottom view of the pruning saw as -taken on view lines 5-5 of Figure l;
Figure 6 is a front view of a cutting tooth, in schematic illus-tration, as it is entering a wood member in a start up mode;
Figure 7 is a side view of the cutting tooth illustrated in Figure 6;
Figure 8 is a front view of the cutting tooth illus-trated in a full cut mode; and Figure 9 is a side view of the cutting tooth illustrated in Figure 8.
Referring to Figure 1 of the drawings, a pruning saw 10 is illus-trated having an elonga-ted blade 12 to which a handle 14 is attached at one end. The saw 10 is a pull type saw, meaning that it is designed to cut as the blade 12 is being pulled over and through a ]imb 16 as indicated by arrow 18.
The forward or push motion of the saw is simply a return motion with little or no cutting taking place. (The invention is however, readily applicable to push type saws wherein the cutting teeth are reversed.) In general, the sawing action involves the gripping of the handle 14 and while reciprocally drawing the blade in the cutting direction 18 with the cutting bottom edge of the blade engaging limb 16, the handle is urged in a forward pivotal motion as indicated by arrow 20 for urging the blade 12 into the limb 16.
Referring now to Figures 2 thru 5, it will be understood that the cutting edge of the blade 12 comprises a sequence of cutting teeth 22. Each cutting tooth 22 includes a front surface 24 and a bottom surface 26. These surfaces are formed to cooperatively produce the controlled cutting function previously described. The tooth configuration is completed by the forming of the rear surface 28 which, together with the front surface of the following tooth, forms gullet 30 i.e., the relief for removal of wood chips which is furtller explailled in the "Operation" section.
As will be apparent by reEerence to Figures 3, 4, and 5, the teeth 22 are alternately bent outwardly from the side of the blade 12, first to the right side and then to the left side of -the blade. This bending is a com-bination of bending and twisting to -force the bottom surface 26 outwardly at an angle "a" (Figure 5) relative to the side of the blade. This bending locates the point 32, which is the intersection of the outside edge of surfaces 24 and 26, as the outermost point of the tooth 22. ~This ou-tward positioning of point 32 is typically referred to as the "set" of the saw.) The front surface 24 is formed, as by grinding, to have an angle "b" (Figure 5) relative to the plane of the blade. Using a round abrading surface such as a grinding wheel with a rounded edge (used primarily in pro-duction) or a round file 34 produces the desired hook shape illustrated in Figure 2. The bottom surface 26 is also angled sidewardly and inwardly (in-wardly meaning frora-the bottom edge of the blade towards the opposite or upper edge of the blade) from its outer side edge as by grinding to form an angle "c" (Figure 3) and is further angled rearwardly and inwardly from its leading edge to form angle "D" relative to the direction of cut (Figure 2). The out-side edge alongside surface 26 formed by angle "c" will sometimes be hereafter referred to as the limiting edge, and the bottom surface 26 as the limiting surface.
Specific Dimensions A specific design of a pruning saw which has been produced and utilized, demonstrating the advantages of the invention herein disclosed, will now be described.
A blade was blanked from 1075 steel having a thickness of .0425 inch. rhe blclcle is 1 o. 250 inches long with a varying height from about 1.750 inclles at the handle to about 1.0750 inches at -the opposite, or distal, end.
Ihe blade is slightly concave with a radius oE about 55 inches. These dimen-sions are typical of pruning saws and other dimensions and configurations typical of pruning saws will easily sufEice.
The saw is provided with 25 cutting teeth with notches or gullets 30 formed .250 inch deep. One side of the notch is on a radial line (relative to the concave curvature) which ultimately forms front surface 24, and the other side of the notch is at a 35 degree angle therefrom and forms the rear surface 28 of the preceding tooth. The length of the bottom surface 26 is about .250 inch i.e. a substantial length sufficient to resist the depth seek-ing force of the front surface 24, and the tooth is twisted to form angle "a"
by setting the point 32 outward from the side of the blade a distance .020 inch. The front surface 24 is formed with a round file 34 having a diameter of about .078 inch, set out at an angle "b" of 30 degrees. Top surface 26 is ground with a side angle "c" of 30 degrees and a length angle "d" of about 4 degrees.
Operation The operation of a hand held saw of the present invention is illus-trated in the schematic drawings of Figures 6 thru 9. Figures 6 thru 9 show only one of the cutting teeth but it will be readily appreciated that a preced-ing or following cutting tooth will operate in a similar manner on the other side of the saw blade 12.
Figures 6 and 7 illustrate the cutting tooth in a start up mode.
With very little pressure applied to the blade, the point 32 is maintained at a shallow depth by reason of the resistance generated by the expanding width x and length y o the tooth tha-t must be forced :into the wood 16. ~Vith this shallow penetration, the tooth merely scratches the wood surface at a consis-tent depth and stutter cutting is avoided. Starting the cut on a desired cutting line is thus easily achieved.
After several passes of the saw blade, a sufficient depth is achiev-ed to confine the blade in the cutting line and additional pressure can be safely applied i.e., by pivotal pressure 20 applied by ~he operator's hand and wrist. The increased pressure will increase the depth of cut e.g., as illustrated in Figures 8 and 9. I-lowever, by appropriate design and rcferring specifically to the angles "c" and "d", the resistance of x and y are rapidly built up and restrict the amount of penetration that can reasonably be applied by the operator. Thus a balancing is achieved whereby the drawing force 18 necessary to pull the point 32 through -the wood does not exceed the operator's ability to hold the teeth in the cut. The result is a steady and smooth cutting action, whereby wood chips 36 are stripped from the wood member 16.
Whereas applicant does not wish to be bound to this theory, it is believed that the cutting control that is achieved is largely a result of the elastic compressability of wood fibers. As the cutting edge of the tooth takes its bite, the wood tries to partially fold back behind the cutting edge where it engages the limiting edge of the tooth. The greater the bite the greater this engagement and in the same manner as described for the knife, resistance to such further penetration quickly builds up and of~sets the forces tending to bury the cutting tooth. The unrestricted "digging in" of the prior cutting teeth are believed to be the primary cause of stutter cutting. This is support-ed by the relatively smooth cutting action that is achieved by the present device.
I`he woocl chips (and the wood pclrticles in prior saws) have to be carried out of the kerf ancl thus a sufficiellt gullet 30 (the relief area formed by the notch~ has to be provided. ExperieTIce teaches that a notch .25 inch deep is desirable for this reason. Also, it has been found tha-t the curved front surface 24 is beneficial in directing the flow of the chips 36 away from the cutting point 32.
Modi~ications It will be understood that different types of wood have different degrees of cutting difficulty and thus a more or less aggressive cutting tooth than herein described may be desirable. Such aggressiveness is varied by chang-ing the angles "a", "b", "c" and "d". [t has been found that acceptable ranges for these angles are: angle "a" between 3 and 6; angle "b" between 25 and 40;
angle "c" between 0 and 45; and angle "d" between 1 and 7. (~he desired angle "c" is greatly affected by the width of the blade and a very narrow blade used in soft wood will permit the 0 angle configuration.) The length of the tooth can be changed as well in that only a relatively sma]l portion, length y of Figure 7, is utili~ed for limiting penetration. ~lowever, as the cutter is repeatedly resharpened with file 34, this length is gradually shortened alld thus the life of the saw is affected by shortening the length of the tooth.
Whereas the invention has been found to be most beneficial to hand held wood cutting saws, this is believed due to the particular properties of wood, the slow cutting motion and power limitations inherent in manual cutting, and the design of manual saws which dictate the application of that power.
Other forms of cutting having similar conditions might very well benefit from the invention, which accordingly is not limited to the specific embodiment shown but is encompassed by the claims appended hereto.
~ his invell-tioll relates to cutting tools for cutting wood, e.g. for pruning outdoor trees and shrubs and for carpentry applications.
Hand held cutting tools are generally of two basic types; hand held knives and hand held saws. The basic design for the knife and saw are similar i.e. an elongated blade is provided with a handle at one end. The basic operation for both is also similar i.e., the blade is drawn back and fourth across the desired cutting line while pressure is applied on the blade by a pivotal urging of the operators wrist. The cutting ac-tion, however~ is quite different. The knife utilizes a continuous cutting edge and slices through and thereby separates the material being cut~ while the saw has teeth that individually bite into and remove bits of material thereby digging a trench or kerf as it is commonly called.
The smooth precise cutting action of a knife is highly desirable, but for many applications the knife is simply unsuitable. For example, con-sider a large tree limb. The sharp edge of the knife will easily slice into the wood but only to a very shallow depth. As the blade enters the cut, the cut has to widen. Wood is "elastically" compressable (more or less depending on the type of wood) and thus penetration is permitted simply by the sides of the blade forcing compression of the wood fibers to thereby enlarge the cut.
However, as more of the blade is forced into the cut, the cumulative effect of the resistance by the wood member to this compression vcry quickly renders it very difficult for the operator to continue cutting.
The hand held saw, having its blade edge made up of a sequence of sharp points, (referred to as teeth) cuts a trench that allows free entry of the blade. Typica]ly, the cutting action of the saw involves a drawing of the saw blade coupled with forward pivoting of the wrist to achieve penetration -- 1 -- ,, ~ .
of the tee-th. The teeth dig in and pu].l loose ;n a rapidly repetitive action, and in the process, wood particles are ripped or torn loose from the wood member. As the saw teeth are worked back and forth in the cut, the trench is increased until the desired severing of the wood member is accomplished. rihis cutting action will be herein re:Eerred to as stutter cutting.
A major problem with the sawing blade is that at least in start up, the stutter cutting ma.kes it difficult to hold the blade on the desired line of cut. This diffi.culty is re:ferred to as the saw's tendency to skate and is a major cause of minor accidents experiellced by operators placing their off hand too close to the desired line of cut. Also, the cut is ragged, the cutting efficiency is poor, and using the saw is uncomfortable and often a difficult task for the operator. These problems can be reduced by reducing the space between the teeth (depth and length) bu-t to do so limits the ability of the saw to remove the particles and this undesirably affects the saw's cut-ting capabilities.
Summar,~f~th_____~___on The present invention is directed to the achievement of a cutting saw wherein the cutting action substantia:Lly departs from that of typical stutter cutting of existing saws and approaches more closely the slicing action of a cutting knife, without materially effecting the saw's cu-tting ability.
The invention provides a hand saw for severing wood materials com-prising; a blade having a cutting edge formed by a series of cutting teeth, the spacing between the teeth forming gullets for carrying wood chips, certain of said teeth having a front surface and a bottom surface cooperatively formed for controlled depth cutting of the wood material, said front surface and bot-tom surface intersecting to form a leading cutting edge having a leading cutting point, said bottom surface being angled inwardly relative to the blade from the cutting edge wi-thin a shallow angular range to form a limiting surface whereby penetration of the cutting point into the wood material is limited to a controlled depth.
In general, the cutting teeth are designed to penetrate to a con-trolled depth and to substantially retain that depth to s:Lice away wood chips rather than tear out wood particles. This is accomplished by forming the teeth with an elongated tapered bottom relief surface that controls the depth of cut. With little or no wrist pressure, the points of the teeth are limited to a very shallow depth that is ideal for start up. As a kerf is established, increased wrist pressure achieves increased depth of penetration, bigger bites, and more rapid cutting, all while substantialLy eliminating the undesirable characteristics of stutter cutting.
Detailed Description and Drawings Having thus briefly described the invention, the preferred embodi-ment will now be described in detail with reference to the accompanying drawings, wherein:
Figure 1 is a side view of a pull type pruning saw o-f the present invention;
Figure 2 is an enlarged view of a section of the pruning saw of Figure l;
Figure 3 is a view taken on view lines 3-3 o:E Figure 2 illustrating a cutting tooth of the saw;
Figure 4 is a view taken on view lines 4-4 of Figure 3 illustrating a cutting tooth on the other side of the saw;
Figure ~ is a bottom view of the pruning saw as -taken on view lines 5-5 of Figure l;
Figure 6 is a front view of a cutting tooth, in schematic illus-tration, as it is entering a wood member in a start up mode;
Figure 7 is a side view of the cutting tooth illustrated in Figure 6;
Figure 8 is a front view of the cutting tooth illus-trated in a full cut mode; and Figure 9 is a side view of the cutting tooth illustrated in Figure 8.
Referring to Figure 1 of the drawings, a pruning saw 10 is illus-trated having an elonga-ted blade 12 to which a handle 14 is attached at one end. The saw 10 is a pull type saw, meaning that it is designed to cut as the blade 12 is being pulled over and through a ]imb 16 as indicated by arrow 18.
The forward or push motion of the saw is simply a return motion with little or no cutting taking place. (The invention is however, readily applicable to push type saws wherein the cutting teeth are reversed.) In general, the sawing action involves the gripping of the handle 14 and while reciprocally drawing the blade in the cutting direction 18 with the cutting bottom edge of the blade engaging limb 16, the handle is urged in a forward pivotal motion as indicated by arrow 20 for urging the blade 12 into the limb 16.
Referring now to Figures 2 thru 5, it will be understood that the cutting edge of the blade 12 comprises a sequence of cutting teeth 22. Each cutting tooth 22 includes a front surface 24 and a bottom surface 26. These surfaces are formed to cooperatively produce the controlled cutting function previously described. The tooth configuration is completed by the forming of the rear surface 28 which, together with the front surface of the following tooth, forms gullet 30 i.e., the relief for removal of wood chips which is furtller explailled in the "Operation" section.
As will be apparent by reEerence to Figures 3, 4, and 5, the teeth 22 are alternately bent outwardly from the side of the blade 12, first to the right side and then to the left side of -the blade. This bending is a com-bination of bending and twisting to -force the bottom surface 26 outwardly at an angle "a" (Figure 5) relative to the side of the blade. This bending locates the point 32, which is the intersection of the outside edge of surfaces 24 and 26, as the outermost point of the tooth 22. ~This ou-tward positioning of point 32 is typically referred to as the "set" of the saw.) The front surface 24 is formed, as by grinding, to have an angle "b" (Figure 5) relative to the plane of the blade. Using a round abrading surface such as a grinding wheel with a rounded edge (used primarily in pro-duction) or a round file 34 produces the desired hook shape illustrated in Figure 2. The bottom surface 26 is also angled sidewardly and inwardly (in-wardly meaning frora-the bottom edge of the blade towards the opposite or upper edge of the blade) from its outer side edge as by grinding to form an angle "c" (Figure 3) and is further angled rearwardly and inwardly from its leading edge to form angle "D" relative to the direction of cut (Figure 2). The out-side edge alongside surface 26 formed by angle "c" will sometimes be hereafter referred to as the limiting edge, and the bottom surface 26 as the limiting surface.
Specific Dimensions A specific design of a pruning saw which has been produced and utilized, demonstrating the advantages of the invention herein disclosed, will now be described.
A blade was blanked from 1075 steel having a thickness of .0425 inch. rhe blclcle is 1 o. 250 inches long with a varying height from about 1.750 inclles at the handle to about 1.0750 inches at -the opposite, or distal, end.
Ihe blade is slightly concave with a radius oE about 55 inches. These dimen-sions are typical of pruning saws and other dimensions and configurations typical of pruning saws will easily sufEice.
The saw is provided with 25 cutting teeth with notches or gullets 30 formed .250 inch deep. One side of the notch is on a radial line (relative to the concave curvature) which ultimately forms front surface 24, and the other side of the notch is at a 35 degree angle therefrom and forms the rear surface 28 of the preceding tooth. The length of the bottom surface 26 is about .250 inch i.e. a substantial length sufficient to resist the depth seek-ing force of the front surface 24, and the tooth is twisted to form angle "a"
by setting the point 32 outward from the side of the blade a distance .020 inch. The front surface 24 is formed with a round file 34 having a diameter of about .078 inch, set out at an angle "b" of 30 degrees. Top surface 26 is ground with a side angle "c" of 30 degrees and a length angle "d" of about 4 degrees.
Operation The operation of a hand held saw of the present invention is illus-trated in the schematic drawings of Figures 6 thru 9. Figures 6 thru 9 show only one of the cutting teeth but it will be readily appreciated that a preced-ing or following cutting tooth will operate in a similar manner on the other side of the saw blade 12.
Figures 6 and 7 illustrate the cutting tooth in a start up mode.
With very little pressure applied to the blade, the point 32 is maintained at a shallow depth by reason of the resistance generated by the expanding width x and length y o the tooth tha-t must be forced :into the wood 16. ~Vith this shallow penetration, the tooth merely scratches the wood surface at a consis-tent depth and stutter cutting is avoided. Starting the cut on a desired cutting line is thus easily achieved.
After several passes of the saw blade, a sufficient depth is achiev-ed to confine the blade in the cutting line and additional pressure can be safely applied i.e., by pivotal pressure 20 applied by ~he operator's hand and wrist. The increased pressure will increase the depth of cut e.g., as illustrated in Figures 8 and 9. I-lowever, by appropriate design and rcferring specifically to the angles "c" and "d", the resistance of x and y are rapidly built up and restrict the amount of penetration that can reasonably be applied by the operator. Thus a balancing is achieved whereby the drawing force 18 necessary to pull the point 32 through -the wood does not exceed the operator's ability to hold the teeth in the cut. The result is a steady and smooth cutting action, whereby wood chips 36 are stripped from the wood member 16.
Whereas applicant does not wish to be bound to this theory, it is believed that the cutting control that is achieved is largely a result of the elastic compressability of wood fibers. As the cutting edge of the tooth takes its bite, the wood tries to partially fold back behind the cutting edge where it engages the limiting edge of the tooth. The greater the bite the greater this engagement and in the same manner as described for the knife, resistance to such further penetration quickly builds up and of~sets the forces tending to bury the cutting tooth. The unrestricted "digging in" of the prior cutting teeth are believed to be the primary cause of stutter cutting. This is support-ed by the relatively smooth cutting action that is achieved by the present device.
I`he woocl chips (and the wood pclrticles in prior saws) have to be carried out of the kerf ancl thus a sufficiellt gullet 30 (the relief area formed by the notch~ has to be provided. ExperieTIce teaches that a notch .25 inch deep is desirable for this reason. Also, it has been found tha-t the curved front surface 24 is beneficial in directing the flow of the chips 36 away from the cutting point 32.
Modi~ications It will be understood that different types of wood have different degrees of cutting difficulty and thus a more or less aggressive cutting tooth than herein described may be desirable. Such aggressiveness is varied by chang-ing the angles "a", "b", "c" and "d". [t has been found that acceptable ranges for these angles are: angle "a" between 3 and 6; angle "b" between 25 and 40;
angle "c" between 0 and 45; and angle "d" between 1 and 7. (~he desired angle "c" is greatly affected by the width of the blade and a very narrow blade used in soft wood will permit the 0 angle configuration.) The length of the tooth can be changed as well in that only a relatively sma]l portion, length y of Figure 7, is utili~ed for limiting penetration. ~lowever, as the cutter is repeatedly resharpened with file 34, this length is gradually shortened alld thus the life of the saw is affected by shortening the length of the tooth.
Whereas the invention has been found to be most beneficial to hand held wood cutting saws, this is believed due to the particular properties of wood, the slow cutting motion and power limitations inherent in manual cutting, and the design of manual saws which dictate the application of that power.
Other forms of cutting having similar conditions might very well benefit from the invention, which accordingly is not limited to the specific embodiment shown but is encompassed by the claims appended hereto.
Claims (7)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A hand saw for severing wood materials comprising; a blade having a cutting edge formed by a series of cutting teeth, the spacing between the teeth forming gullets for carrying wood chips, certain of said teeth having a front surface and a bottom surface cooperatively formed for controlled depth cutting of the wood material, said front surface and bottom surface intersecting to form a leading cutting edge having a leading cutting point, said bottom surface being angled inwardly relative to the blade from the cutting edge within a shallow angular range to form a limiting surface whereby penetration of the cutting point into the wood material is limited to a controlled depth.
2. A hand saw as defined in claim 1 wherein the shallow angular range of the bottom surface ("d") is between 1° and 7°.
3. A hand saw as defined in claim 2 wherein said front surface of said certain cutting teeth is rearwardly angled side-to-side relative to the blade to form with said bottom surface a rearwardly angled side-to-side cutting edge with the forwardmost point of the cutting edge forming the leading cutting point, said cutting teeth being offset to project said cutting point outwardly from the side of the blade and with various ones of said certain cutting teeth having cutting points on one side of the blade and other ones of said certain cutting teeth having leading cutting points on the other side of the blade to cut a kerf wider than the width of the blade.
4. A hand saw as defined in claim 3 wherein said cutting edge angle ("b") is within the range of 25° to 40° from the blade, and said cutting teeth are angularly offset relative to the blade within a range of 3° to 6°
("a")
("a")
5. A hand saw as defined in claim 4 wherein said bottom surface is inwardly angled side-to-side from the outer edge thereof ("c") to form a limit-ing edge that controls penetration of the tooth into the wood material.
6. A hand saw as defined in claim 5 wherein said side-to-side angle of the bottom surface ("c") is within the range of 0° to 45°.
7. A hand saw as defined in claim 6 wherein the rearward angle ("b") of the front surface is formed with a round abrading surface to provide a hooked configuration in the cutting tooth.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US58398384A | 1984-02-27 | 1984-02-27 | |
| US583,983 | 1984-02-27 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1224386A true CA1224386A (en) | 1987-07-21 |
Family
ID=24335415
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000475107A Expired CA1224386A (en) | 1984-02-27 | 1985-02-26 | Hand held cutting tools |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS60204301A (en) |
| CA (1) | CA1224386A (en) |
| DE (1) | DE3506959A1 (en) |
| FR (1) | FR2560105B3 (en) |
| GB (1) | GB2154505B (en) |
| IT (1) | IT1181753B (en) |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB306808A (en) * | 1928-02-25 | 1929-10-31 | Erik August Bolinder | Improvements in or relating to saw blades |
| GB641636A (en) * | 1948-05-04 | 1950-08-16 | Gustav Jirikowski | Improvements in and relating to saws used for felling trees |
| GB772481A (en) * | 1952-05-23 | 1957-04-17 | Arthur Gretton Tomkies | Improvements in and relating to saws |
| GB724784A (en) * | 1953-01-20 | 1955-02-23 | Aspin Frank Metcalfe | Improvements in or relating to power saw chains |
| US3374815A (en) * | 1965-08-30 | 1968-03-26 | Millers Falls Co | Woodcutting saw blade |
| US4292871A (en) * | 1979-02-01 | 1981-10-06 | The L. S. Starrett Company | Welded edge band saw tooth geometry |
| US4218820A (en) * | 1979-03-27 | 1980-08-26 | William Cleva | Hand-actuated chain saw |
| JPS5832885U (en) * | 1981-08-27 | 1983-03-03 | ワイケイケイ株式会社 | Swivel casement window |
-
1985
- 1985-02-25 FR FR8502663A patent/FR2560105B3/en not_active Expired
- 1985-02-26 GB GB08504875A patent/GB2154505B/en not_active Expired
- 1985-02-26 CA CA000475107A patent/CA1224386A/en not_active Expired
- 1985-02-27 DE DE19853506959 patent/DE3506959A1/en not_active Ceased
- 1985-02-27 JP JP60038603A patent/JPS60204301A/en active Pending
- 1985-02-27 IT IT47739/85A patent/IT1181753B/en active
Also Published As
| Publication number | Publication date |
|---|---|
| FR2560105B3 (en) | 1988-04-29 |
| IT8547739A1 (en) | 1986-08-27 |
| IT1181753B (en) | 1987-09-30 |
| FR2560105A1 (en) | 1985-08-30 |
| GB2154505B (en) | 1988-01-13 |
| GB8504875D0 (en) | 1985-03-27 |
| JPS60204301A (en) | 1985-10-15 |
| GB2154505A (en) | 1985-09-11 |
| IT8547739A0 (en) | 1985-02-27 |
| DE3506959A1 (en) | 1985-08-29 |
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