CA1198273A - Cutting implements - Google Patents
Cutting implementsInfo
- Publication number
- CA1198273A CA1198273A CA000436656A CA436656A CA1198273A CA 1198273 A CA1198273 A CA 1198273A CA 000436656 A CA000436656 A CA 000436656A CA 436656 A CA436656 A CA 436656A CA 1198273 A CA1198273 A CA 1198273A
- Authority
- CA
- Canada
- Prior art keywords
- work
- engaging
- blades
- edges
- cutting
- 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
Abstract
CUTTING IMPLEMENTS
ABSTRACT OF THE DISCLOSURE
A shear has a first elongate blade having a generally convex work-engaging-cutting-edge and an elongate handle portion and a second elongate blade having a generally convex work-engaging-cutting-edge and an elongate handle portion and a pivot means for pivotally linking together the first and second blades. In closing stroke, the blades are swingable toward each other and their cutting edges oppose each other in facing relationship with the defined included angle between the blades at any point of their intersection having certain value in the order of 17°? 3°.
The combined included angles of the bevels of the cutting edges of the blades is in the order of not less than 80 and not more than 120°.
ABSTRACT OF THE DISCLOSURE
A shear has a first elongate blade having a generally convex work-engaging-cutting-edge and an elongate handle portion and a second elongate blade having a generally convex work-engaging-cutting-edge and an elongate handle portion and a pivot means for pivotally linking together the first and second blades. In closing stroke, the blades are swingable toward each other and their cutting edges oppose each other in facing relationship with the defined included angle between the blades at any point of their intersection having certain value in the order of 17°? 3°.
The combined included angles of the bevels of the cutting edges of the blades is in the order of not less than 80 and not more than 120°.
Description
This in~ention relates to improvements ~n sheari~g tools such as shears 9 scissors, tin snipsy secateurs~ and other hand tools and will be described with particular reference to hedge shear It is to be under~tood however that the principles herein exemplified may be applied with equal ease to scissors and other types of hand-manipulated instrumentsO
The invention envisions cutting implements in which~
in the cut~ing action, the edges of two cooperating blades, in sub~tantial con ac~ with each other, move toward and then past each other as facilitated by a piv~t about which the blades ro~ate. The novelty lies in the fact that the operating edge~ of the blades are of arcuate configuration so tha~ the cutting action is con~tant from the initiation to termination of the cutting stroke~ a feature aided nd ~betted both ~y the particular arcuate configuration of the opposing cutting edges of the blades and by a novel dimensioning of the included ~ngle between the cutting edges With known prior art shears, particularly hedge shears, there i~ the aggravating tendency to push or extrude the work along and relatlve to the cutting edges as the cutting or closing a¢tion ensues. Such extrusion is in the form of a ~liding of the work along and rela~ive t~ the cutting edges with the result that a portion of the cutting ac~ion is obviously wasted.
Any co~ventional shear, particularly a hedge shear~ wlll exhibit, to some degree, this tendency to extrude. As the cutting stroke erlsues, the work is pushed away from the apex of the blades and along the blade edges until some point therealong is reached where that sliding actlon~ having slowed down~ i~
finally stopped, whereupon the critlcal cutting action in the ~11 4 1~
fo~m of the biting of the blades into the work finally commences. This is seriously disadvantageous as the obvious desideratum is to obtain not only an optimum cutting ction in the area of the greatest force (that is~ in the area nearest the pivot where ~u~h action should be initlated~ but also a constant and c~ntinuous cutting action throughout tha cutting s~roke.
To overcome this n~torious tendency to extrude, serrated blades have been employed, as have notched ~lades ?
either ~pproach constituting an express recognition of the extruding problem. The serrating of a single blade is shown in V~S. patent ~3J650,028 to LaPointe, and of both blades i5 shown in U.SO patent ~2~1~1,236 to McDonald. The notching of a blade is sh~wn in U.S. patent ~198909355 to Bailey.
The use of serrations represents a sacrifice of one or both of the blades as far as eficient cutting action is concerned. The conventional notch9 while it may be helpful in cutting heavy growth, is actually a drawback when the shear is used to cut ligh growths, such as grass and the like, due to the limitations in the shearing action.
We have arrived at a solution which provides a constant shearing action rom the commencement to termination of the cutting stroke and defined by the provision of an included angle between the blades in the cutting stroke which is not so 8mall as to jeopardize the shearing e~ficiency and is yet not 80 large as to ,encourage axtrusion. The solution represents a strikin~ o an optimum balance between s~earing action and extruding tendency.
In prior art shears, the blades, in ully-opened position, may bls generally disposed so as ~o define an included angle approximating 90 or even more7 sometimes even
The invention envisions cutting implements in which~
in the cut~ing action, the edges of two cooperating blades, in sub~tantial con ac~ with each other, move toward and then past each other as facilitated by a piv~t about which the blades ro~ate. The novelty lies in the fact that the operating edge~ of the blades are of arcuate configuration so tha~ the cutting action is con~tant from the initiation to termination of the cutting stroke~ a feature aided nd ~betted both ~y the particular arcuate configuration of the opposing cutting edges of the blades and by a novel dimensioning of the included ~ngle between the cutting edges With known prior art shears, particularly hedge shears, there i~ the aggravating tendency to push or extrude the work along and relatlve to the cutting edges as the cutting or closing a¢tion ensues. Such extrusion is in the form of a ~liding of the work along and rela~ive t~ the cutting edges with the result that a portion of the cutting ac~ion is obviously wasted.
Any co~ventional shear, particularly a hedge shear~ wlll exhibit, to some degree, this tendency to extrude. As the cutting stroke erlsues, the work is pushed away from the apex of the blades and along the blade edges until some point therealong is reached where that sliding actlon~ having slowed down~ i~
finally stopped, whereupon the critlcal cutting action in the ~11 4 1~
fo~m of the biting of the blades into the work finally commences. This is seriously disadvantageous as the obvious desideratum is to obtain not only an optimum cutting ction in the area of the greatest force (that is~ in the area nearest the pivot where ~u~h action should be initlated~ but also a constant and c~ntinuous cutting action throughout tha cutting s~roke.
To overcome this n~torious tendency to extrude, serrated blades have been employed, as have notched ~lades ?
either ~pproach constituting an express recognition of the extruding problem. The serrating of a single blade is shown in V~S. patent ~3J650,028 to LaPointe, and of both blades i5 shown in U.SO patent ~2~1~1,236 to McDonald. The notching of a blade is sh~wn in U.S. patent ~198909355 to Bailey.
The use of serrations represents a sacrifice of one or both of the blades as far as eficient cutting action is concerned. The conventional notch9 while it may be helpful in cutting heavy growth, is actually a drawback when the shear is used to cut ligh growths, such as grass and the like, due to the limitations in the shearing action.
We have arrived at a solution which provides a constant shearing action rom the commencement to termination of the cutting stroke and defined by the provision of an included angle between the blades in the cutting stroke which is not so 8mall as to jeopardize the shearing e~ficiency and is yet not 80 large as to ,encourage axtrusion. The solution represents a strikin~ o an optimum balance between s~earing action and extruding tendency.
In prior art shears, the blades, in ully-opened position, may bls generally disposed so as ~o define an included angle approximating 90 or even more7 sometimes even
- 2 -~L~9~ 3 as much as an included angle of 1~5 ~ 130) relative to each other~ Then, ln the cIosing stroke, they may be moved in relative positions so that, immediately prior to full closure, the blades at their outermost points, will have as~umed, as to each other, an included angle approximating 10 - 12. With the conventional shear9 obviou~ly, the smaller included angle is found near the ~board extreme and the larger angle is found near the i.nboard extreme of the cutting s~roke.
Our prima~y ~bject of providing an i~proved cutting action ls accomplished with a shear distinguished by a pair of opposed pivotally-mounted blades~ each having a specific arcuate curvature along its cutting edge. The cut~ing blades are each curved tow~rd the other; ~hat is, the blades have convexly curved edge39 the convexity being toward each other.
In the case of the shear of this inventlon, the included angle defined between the cutting edges of the blades during the cutting stro~e is a relatively cons~ant one and ~ignificantly is maintained at approximately 1? 3.
That angle can be a constant one i.n ~he order of 17 throughout the cutting s~-rnke, or 16, or 18 or comet~ing else as all~wed by the limitations of the toler~nce. Or the angle can be an ever increasing one, s~y from 14 or lS in the pivotal or inboard area to say from 19 or 20 in the outboard area immediately preceding full blade closure. Or the angle can be an ever decreasing one, say from 18 or 19 in the inboard area to say from 15 or 16 in the outboard area~
The salient crit:ical feature i8 that the included angle is a relatively con~t:an~ one approximating 17~ ~ 3.
In our developmental work7 it was recognized that while to increa~;e the included angle was to increase the
Our prima~y ~bject of providing an i~proved cutting action ls accomplished with a shear distinguished by a pair of opposed pivotally-mounted blades~ each having a specific arcuate curvature along its cutting edge. The cut~ing blades are each curved tow~rd the other; ~hat is, the blades have convexly curved edge39 the convexity being toward each other.
In the case of the shear of this inventlon, the included angle defined between the cutting edges of the blades during the cutting stro~e is a relatively cons~ant one and ~ignificantly is maintained at approximately 1? 3.
That angle can be a constant one i.n ~he order of 17 throughout the cutting s~-rnke, or 16, or 18 or comet~ing else as all~wed by the limitations of the toler~nce. Or the angle can be an ever increasing one, s~y from 14 or lS in the pivotal or inboard area to say from 19 or 20 in the outboard area immediately preceding full blade closure. Or the angle can be an ever decreasing one, say from 18 or 19 in the inboard area to say from 15 or 16 in the outboard area~
The salient crit:ical feature i8 that the included angle is a relatively con~t:an~ one approximating 17~ ~ 3.
In our developmental work7 it was recognized that while to increa~;e the included angle was to increase the
- 3 -~8~73 cutting efflciencyi Thi~ was ~o only up to a po;nt; such angle -- increase also offered the disadvantage that it led to an extruding of the material when and if a certaill value of included angle was reached in the absence of course of the aforemen~ioned serrating or notching feature.
The significant discovery was made that optimum cutting efficiency as well as work reten~ion c~pabili~y are obtainable when and ifp in the cutting stroke7 the included angle is maintained within the all-critical range of 17~ ~ 3 wi~h that ~ngle remaining con~tant or at least chang;ng only gradually between the point where the cutting edges irst contact each other, at stroke initiation7 to the point close to stroke terminatior~
Should that defined included angle fall bel~w 14, shearing per~o~mance was seen to deteni~rate rapidly; if extended above 20, the tendency to ext~ude was seen to accelerate.
The blades9 at all relative positions9 are deslrably in contact at the point-contact intersection of their cutting edges so as to define an included angle which is never less than 14 or more than 20~
Additional to the desirability for an arcuate curvature in the cutting edge of each of the blades from pivot to outer extremity and wherein the lncluded angle defined therebetween as the cutting ~troke ensues is held within certain limits, our investigati~e work led us to the further discovery that optimum results ~re obtained when the total included angle ~efined by the t:wo opposed cutting edges is desirably between 80 and 120.
If the total included angle is less than 80, the edges te~d to self distruct. If it exceads 120, the slippage fe~ture is disadvantageously accelerated.
The significant discovery was made that optimum cutting efficiency as well as work reten~ion c~pabili~y are obtainable when and ifp in the cutting stroke7 the included angle is maintained within the all-critical range of 17~ ~ 3 wi~h that ~ngle remaining con~tant or at least chang;ng only gradually between the point where the cutting edges irst contact each other, at stroke initiation7 to the point close to stroke terminatior~
Should that defined included angle fall bel~w 14, shearing per~o~mance was seen to deteni~rate rapidly; if extended above 20, the tendency to ext~ude was seen to accelerate.
The blades9 at all relative positions9 are deslrably in contact at the point-contact intersection of their cutting edges so as to define an included angle which is never less than 14 or more than 20~
Additional to the desirability for an arcuate curvature in the cutting edge of each of the blades from pivot to outer extremity and wherein the lncluded angle defined therebetween as the cutting ~troke ensues is held within certain limits, our investigati~e work led us to the further discovery that optimum results ~re obtained when the total included angle ~efined by the t:wo opposed cutting edges is desirably between 80 and 120.
If the total included angle is less than 80, the edges te~d to self distruct. If it exceads 120, the slippage fe~ture is disadvantageously accelerated.
- 4 -In sumrnary7 the scissor~like device may be said to consist of a pair of pivotally~secured blades and a pair of handles with a pivotal connaction providing a pivot axis for interconnecting the ~lades and handles so that the movement of the handles in closing stroke t~ward and in opening stroke away from e~ch other generates a corresponding movement of the blades in facial engagement with each other such that the size of the work-receiving space is reduced and increased respectively~ same being singularized by the work engaging edges of the blades each being of arcuate conf iguration and of cour~e disposed in opposed facing relationship. In the clo~ing stroke" they offer a work~
receiving-opening defining a relatively constant in~-luded angle having a value of 17 ~ 3~. The cut ing edge of one blade will have a combination holding edge and blunt edge, which preferentially will be in the range of 60 and the cutting edge of the other blade will preferentially be in the range of 45O
A certain embodiment of shear, in accordance with the invention7 will now be described7 b~ way of example~
with reference to the accompanying drawingsg in which~
Figs. 1 - 3 are views in top plan of a hedge shear of the invention in an openedg partially closed, and nearly fully closed positions respectively;
Fig. 4 is an exaggera~ed sectional view on the line 4-4 of Fig. l; and Fig. 5 is a schematic representation showing the arcuate curvature of the cutting edges of 3~ the blades and the relationship thereof to lines tangent to the respective lines of curvature.
2~73 The shear includes an upper blade 10 and a lower blade 12 disposed in the us~al criss-cross relation and pivotally int rconnected by a pivot bolt 14 or other suit~ble fastening device, Pxtended, in known manner, at their point of intersection through strategically-located9 ver~ically~
aligned blade apertures~
A nu~ ~not sh~wn) may be ~hreadedly engaged with the outboard ~r lower end of ~he pivot holt and a spring washer of dished form may be sleeved on the pivot bolt to provide a desired permanent force between the blades. Alternative pivotal me~n~ are conceivable, The blades have suita~le handle p~rti~ns 20 and 22 for grasping the ~hear and swinging the respective blades 10 and 12 abou~ ~he pivot means 14 in the cutting functio~.
The blades 10 and 12 will have confron'cable inner aces 30 and 32 respectively and oppositely facing outer faces 40 and 42 respec~ively.
The inner faces 30 and 32 upon assembly wlll be disposed in generally the same plane so that ~hey will slide in facial engagement when the ~lades are swung about the pivot means.
The desired arcuate configuration of the blade cutting is generated ma~hematically so as to allow the definition~
cooperantly with the identical arcuate configuration of the edge of the complemental blade, of an included angle in the order of 17 ~ 3 at any point of intersection of the opposed ~lades when plvotally interrelated.
The upper and lower blades have generally-convex work-engaging cutting edges 15 and 19 respectively, which edges oppose each other in facing relationship.
In Fig. 5, we have shown a schematic representation illustrating the arcuate curvature o~ the cutting edges of the ~ 6 ~
Z'~3 upper and 1i3wer blades ~d the relationship thereof to respectiva lines x-x tangent to the respective lines of curvature. When assembled, the cutting edges are so disposed that the tangent lines thereo~ bisect each other and are generally normal to an imaginary line subtending the con~ex edges of the blades adjacent the pivotally~linked blades.
The work engaging dges in the closing stroke define an opening having an:included angle of the ~alue of ~7 ~ 3 Upper blade 10 will be provided with a first beveled so~called "blun~' surace 11 disposed at an angle ~f 45 relative to its outer face 40 and with a second beveled so-called ~Iholding~ surface 13 disposed at ~n angle of 60 relative to its outer face 40 in the defining of what is known as the cutting edge 15 of the upper blade.
Lower bl~de 12 is provided with a beveled so-called "cutting" surface 17 disposed at an angle of 45~ relative to its ou~er face 42 in the defining of what is known as the cutting edge 19 of the lower blade.
The beveled surfaces extend ~ver ~he ma30r or shearing portion of the blade lengths and aGross the blade thicknesses from their outer faces to their inner faces.
Judicious experimentation showed that the totality of the bQvels in the case of the confronting cutting edges should not be less than 80 in value or more than 120 in value.
In the exemplification delineated above, the upper blade bevel of 60 and the lower blade bevel of 45 offers an ideal arr~ngement with optimum shearing eficiency and wherein t~e totaliky Qf the included angle i~ in the order of 105 ~ Various changes in the angularlzation o~ the respective cutting edges could conceivably be made 30 long as the totality of the included angle is not less than 80 or not greater than 120.
1~9~ 73 For example~ typical alternate arrangements could exploit angles of 40 and 50~ or 45 and 65 , etc. Each offers an excellent combination of reten~ion means and positive cutting means and is well within the 80 - 120 parametersO
The holding surface ~f one bl~de provides an effective retaining means for holding the work against movement along the longitudinal extent of the blades as their cutting edges are being brought together for the cutting action~
receiving-opening defining a relatively constant in~-luded angle having a value of 17 ~ 3~. The cut ing edge of one blade will have a combination holding edge and blunt edge, which preferentially will be in the range of 60 and the cutting edge of the other blade will preferentially be in the range of 45O
A certain embodiment of shear, in accordance with the invention7 will now be described7 b~ way of example~
with reference to the accompanying drawingsg in which~
Figs. 1 - 3 are views in top plan of a hedge shear of the invention in an openedg partially closed, and nearly fully closed positions respectively;
Fig. 4 is an exaggera~ed sectional view on the line 4-4 of Fig. l; and Fig. 5 is a schematic representation showing the arcuate curvature of the cutting edges of 3~ the blades and the relationship thereof to lines tangent to the respective lines of curvature.
2~73 The shear includes an upper blade 10 and a lower blade 12 disposed in the us~al criss-cross relation and pivotally int rconnected by a pivot bolt 14 or other suit~ble fastening device, Pxtended, in known manner, at their point of intersection through strategically-located9 ver~ically~
aligned blade apertures~
A nu~ ~not sh~wn) may be ~hreadedly engaged with the outboard ~r lower end of ~he pivot holt and a spring washer of dished form may be sleeved on the pivot bolt to provide a desired permanent force between the blades. Alternative pivotal me~n~ are conceivable, The blades have suita~le handle p~rti~ns 20 and 22 for grasping the ~hear and swinging the respective blades 10 and 12 abou~ ~he pivot means 14 in the cutting functio~.
The blades 10 and 12 will have confron'cable inner aces 30 and 32 respectively and oppositely facing outer faces 40 and 42 respec~ively.
The inner faces 30 and 32 upon assembly wlll be disposed in generally the same plane so that ~hey will slide in facial engagement when the ~lades are swung about the pivot means.
The desired arcuate configuration of the blade cutting is generated ma~hematically so as to allow the definition~
cooperantly with the identical arcuate configuration of the edge of the complemental blade, of an included angle in the order of 17 ~ 3 at any point of intersection of the opposed ~lades when plvotally interrelated.
The upper and lower blades have generally-convex work-engaging cutting edges 15 and 19 respectively, which edges oppose each other in facing relationship.
In Fig. 5, we have shown a schematic representation illustrating the arcuate curvature o~ the cutting edges of the ~ 6 ~
Z'~3 upper and 1i3wer blades ~d the relationship thereof to respectiva lines x-x tangent to the respective lines of curvature. When assembled, the cutting edges are so disposed that the tangent lines thereo~ bisect each other and are generally normal to an imaginary line subtending the con~ex edges of the blades adjacent the pivotally~linked blades.
The work engaging dges in the closing stroke define an opening having an:included angle of the ~alue of ~7 ~ 3 Upper blade 10 will be provided with a first beveled so~called "blun~' surace 11 disposed at an angle ~f 45 relative to its outer face 40 and with a second beveled so-called ~Iholding~ surface 13 disposed at ~n angle of 60 relative to its outer face 40 in the defining of what is known as the cutting edge 15 of the upper blade.
Lower bl~de 12 is provided with a beveled so-called "cutting" surface 17 disposed at an angle of 45~ relative to its ou~er face 42 in the defining of what is known as the cutting edge 19 of the lower blade.
The beveled surfaces extend ~ver ~he ma30r or shearing portion of the blade lengths and aGross the blade thicknesses from their outer faces to their inner faces.
Judicious experimentation showed that the totality of the bQvels in the case of the confronting cutting edges should not be less than 80 in value or more than 120 in value.
In the exemplification delineated above, the upper blade bevel of 60 and the lower blade bevel of 45 offers an ideal arr~ngement with optimum shearing eficiency and wherein t~e totaliky Qf the included angle i~ in the order of 105 ~ Various changes in the angularlzation o~ the respective cutting edges could conceivably be made 30 long as the totality of the included angle is not less than 80 or not greater than 120.
1~9~ 73 For example~ typical alternate arrangements could exploit angles of 40 and 50~ or 45 and 65 , etc. Each offers an excellent combination of reten~ion means and positive cutting means and is well within the 80 - 120 parametersO
The holding surface ~f one bl~de provides an effective retaining means for holding the work against movement along the longitudinal extent of the blades as their cutting edges are being brought together for the cutting action~
Claims (9)
1. A cutting device comprising in combination a first elongate blade having a generally convex work-engaging-edge for engaging the work to be cut and an elongate handle portion, a second elongate blade having a generally convex work-engaging-edge for engaging the work to be cut and an elongate handle portion, a pivot means for pivotally linking together the first and second blades whereby the work-engaging edges of the blades oppose one another in facing relationship and in swinging in the closing stroke toward each other define an included angle, the defined included angle between the work-engaging edges of the blades at any point of their intersection from the initiation to the termination of the closing stroke being a constant value, the work-engaging-edges having bevels with the totality of the included angles of the edges being in the order of at least 80° and not in excess of 120°.
2. A cutting device comprising in combination:
a first elongate blade having a generally convex cutting edge for engaging the work to be cut and an associated elongate handle portion, a second elongate blade having a generally convex cutting edge for engaging the work to be cut and an associated elongate handle portion, a pivot means for pivotally linking together the first and second blades whereby the cutting edges of the blades oppose one another in facing relationship and in swinging in the closing stroke toward each other define an included angle, the defined included angle between the cutting edges of the blades at any point of their intersection from stroke initiation to stroke termination having a relatively constant value of 17° ? 3°, the work-engaging-edge having bevels with the totality of the included angles of the edges being in the order of at least 80° and not in excess of 120°.
a first elongate blade having a generally convex cutting edge for engaging the work to be cut and an associated elongate handle portion, a second elongate blade having a generally convex cutting edge for engaging the work to be cut and an associated elongate handle portion, a pivot means for pivotally linking together the first and second blades whereby the cutting edges of the blades oppose one another in facing relationship and in swinging in the closing stroke toward each other define an included angle, the defined included angle between the cutting edges of the blades at any point of their intersection from stroke initiation to stroke termination having a relatively constant value of 17° ? 3°, the work-engaging-edge having bevels with the totality of the included angles of the edges being in the order of at least 80° and not in excess of 120°.
3. A cutting device comprising in combination:
a first elongate blade having a generally convex cutting edge for engaging the work to be cut and an associated elongate handle portion, a second elongate blade having a generally convex cutting edge for engaging the work to be cut and an associated elongate handle portion, a pivot means for pivotally linking together the first and second blades whereby the cutting edges of the blades oppose one another in facing relationship and in swinging in the closing stroke toward each other define an included angle, the defined included angle between the cutting edges of the blades at any point of their intersection from stroke initiation to stroke termination having a relatively constant value of 17° ? 3°, the cutting edges having corresponding tangent lines bisecting each other and being generally normal to an imaginary line subtending the pivot of the blades.
a first elongate blade having a generally convex cutting edge for engaging the work to be cut and an associated elongate handle portion, a second elongate blade having a generally convex cutting edge for engaging the work to be cut and an associated elongate handle portion, a pivot means for pivotally linking together the first and second blades whereby the cutting edges of the blades oppose one another in facing relationship and in swinging in the closing stroke toward each other define an included angle, the defined included angle between the cutting edges of the blades at any point of their intersection from stroke initiation to stroke termination having a relatively constant value of 17° ? 3°, the cutting edges having corresponding tangent lines bisecting each other and being generally normal to an imaginary line subtending the pivot of the blades.
4. The cutting device of Claim 3, the cutting edges of the blades having bevels with respect to the respective outer faces of the respective blades and defining a totality of the included angles being in the order of at least 80° and not in excess of 120°.
5. The cutting device of Claim 3, the cutting edges of the blades having bevels with respect to the respective outer faces of the respective blades with the totality of the defined included angles of the bevels being in the order of between 80° and 120°.
6. A cutting device comprising in combination:
a first elongate blade having a generally convex work-engaging edge for engaging the work to be cut, a first elongate handle, a second elongate blade having a generally convex work-engaging-edge for engaging the work to be cut, a second elongate handle, a pivot means for allowing the movement of the blades in closing and opening strokes with the work-engaging edges opposing one another in facing relationship, each blade being connected to a respective one of the handles with movement of the handles in closing stroke toward and in opening stroke away from each other inducing corresponding movement of the blades about the pivotal connection such that the size of the subtended angle between the work-engaging edges is in the order of 17 ? 3 , the work-engaging-edges having bevels with the totality of the included angles of the edges being in the order of at least 80° and not in excess of 120°.
a first elongate blade having a generally convex work-engaging edge for engaging the work to be cut, a first elongate handle, a second elongate blade having a generally convex work-engaging-edge for engaging the work to be cut, a second elongate handle, a pivot means for allowing the movement of the blades in closing and opening strokes with the work-engaging edges opposing one another in facing relationship, each blade being connected to a respective one of the handles with movement of the handles in closing stroke toward and in opening stroke away from each other inducing corresponding movement of the blades about the pivotal connection such that the size of the subtended angle between the work-engaging edges is in the order of 17 ? 3 , the work-engaging-edges having bevels with the totality of the included angles of the edges being in the order of at least 80° and not in excess of 120°.
7. A work cutting device comprising in combination:
a. first elongate blade having a generally convex work-engaging-edge for engaging the work to be cut and a first elongate handle fixed thereto, a second elongate blade having a generally convex work-engaging-edge for engaging the work to be cut and a second elongate handle fixed thereto, the first and second blades and respective handles being pivotally interengaged with the work-engaging-edges opposing each other in facing relationship, a relatively constant included angle of a minimum of 14° and a maximum of 20°, the size of the subtended angle between the work-engaging edges is in the order of 17° ? 3°, the work-engaging-edges having bevels with the totality of the included angles of the edges being in the order of at least 80° and not in excess of 120°.
a. first elongate blade having a generally convex work-engaging-edge for engaging the work to be cut and a first elongate handle fixed thereto, a second elongate blade having a generally convex work-engaging-edge for engaging the work to be cut and a second elongate handle fixed thereto, the first and second blades and respective handles being pivotally interengaged with the work-engaging-edges opposing each other in facing relationship, a relatively constant included angle of a minimum of 14° and a maximum of 20°, the size of the subtended angle between the work-engaging edges is in the order of 17° ? 3°, the work-engaging-edges having bevels with the totality of the included angles of the edges being in the order of at least 80° and not in excess of 120°.
8. In the work cutting device of Claim 7, the work-engaging-edges in the closing stroke defining an ever-narrowing opening having an ever-increasing included angle starting from at least 14° at the initiation of the closing stroke and ending at no more than 20° at the termination of the closing stroke,
9. In the work cutting device of Claim 7, the defined included angle between the blades at any point of their intersection along the lengths of the blades having a value of between 14° and 20° between closing stroke initiation and termination.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000436656A CA1198273A (en) | 1983-09-14 | 1983-09-14 | Cutting implements |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000436656A CA1198273A (en) | 1983-09-14 | 1983-09-14 | Cutting implements |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1198273A true CA1198273A (en) | 1985-12-24 |
Family
ID=4126066
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000436656A Expired CA1198273A (en) | 1983-09-14 | 1983-09-14 | Cutting implements |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1198273A (en) |
-
1983
- 1983-09-14 CA CA000436656A patent/CA1198273A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry | ||
| MKEX | Expiry |
Effective date: 20030914 |