CA1202772A - Cutting apparatus - Google Patents
Cutting apparatusInfo
- Publication number
- CA1202772A CA1202772A CA000412525A CA412525A CA1202772A CA 1202772 A CA1202772 A CA 1202772A CA 000412525 A CA000412525 A CA 000412525A CA 412525 A CA412525 A CA 412525A CA 1202772 A CA1202772 A CA 1202772A
- Authority
- CA
- Canada
- Prior art keywords
- blade
- piercing
- cutting
- pivot
- tube
- 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
- B23D35/00—Tools for shearing machines or shearing devices; Holders or chucks for shearing tools
-
- 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
- B23D29/00—Hand-held metal-shearing or metal-cutting devices
- B23D29/002—Hand-held metal-shearing or metal-cutting devices for cutting wire or the like
Abstract
TITLE: CUTTING APPARATUS
INVENTOR: Stuart Malcolm Harrison ABSTRACT OF DISCLOSURE
A pair of cutter blades is provided for cutting sheet metal in flat tubular form. The blades are pivotally connected together in scissors-fashion so as to be capable of relative movement between each other.
At least one of the blades is formed with a cutting edge comprising a piercing point or region having on each side portions which trail the leading extremity of the piercing point or region considered in the direction of cutting, whereby in operation after initial piercing of the metal to be cut, and on continued cutting, the incision made by the piercing point or region increases away from the pierced region towards the sides of the material being cut. The blades may be operated by means of a piston and cylinder device driving a pair of links connecting the piston to the two blades at positions off-set from the pivotal axis of the two blades.
INVENTOR: Stuart Malcolm Harrison ABSTRACT OF DISCLOSURE
A pair of cutter blades is provided for cutting sheet metal in flat tubular form. The blades are pivotally connected together in scissors-fashion so as to be capable of relative movement between each other.
At least one of the blades is formed with a cutting edge comprising a piercing point or region having on each side portions which trail the leading extremity of the piercing point or region considered in the direction of cutting, whereby in operation after initial piercing of the metal to be cut, and on continued cutting, the incision made by the piercing point or region increases away from the pierced region towards the sides of the material being cut. The blades may be operated by means of a piston and cylinder device driving a pair of links connecting the piston to the two blades at positions off-set from the pivotal axis of the two blades.
Description
~27~7,~
BACKGROUND TO THE X~JVENTION - -This invention relates to apparatus for shearing material in flat, tubular or rod ~orrn and more especially but not solely for exhaust pipes.
For the purpose of the replacement ~f exhaust sys~ems in motor vehicles the need has arisen for speedy removal of exhausk pipes prior to fitting replacement parts. The pipes are generally from 31 mm.
to 58 mm. in diameter having a wall thickness of 16 S.W.G.
STATEMENT OF PRIOR ARI
~ ttempts were made to use well known hand operated cutting implements often termed bolk-croppers~ These were found to be unsuccessful since after the initial difficulty of grippin~ the pipe was overcome the latter merely flattened, presenting to the cropper blades a double wall thickness joined by a bend which resisted shearing. Shears having park-circular cutting edges were found ~o be similarly unsatisfactory.
~ It was evident that insufficient power was being transmitted to khe cutter blades to overcome the resistance offered by the fold at the initiakion of the cutting operation. Attention was, therefore, turned to hydraulic power. Two devices were considered namely a cable cutter and a pillar cutter for emergency use on vehicles. Whilsk these were amply capable of cutting ., ' ~
7~
through exhaust pipes they were extremely heavy pieces of equipment quite unsuita~le for easy manipulation by a mechanic working beneath a vehicle.
OBJECT OF THE INVENTION
An object of the invention is to provide cu~ter blades which permit ease o~ use of a hand held tool ~or the purpose of cutting sheet metal9 especially exhaust pipes of motor vehicles.
The inventor decided to approach the problem from the point of vie~ of blade design~ It occurred to him that if the blades could be made to pierce the tube less power would be needed to effect a shearing action~
S~MMARY OF THE INVENTION
According to the invention there is provided a pair of cutter blades for relative movement between each other for cutting sheet metal in flat, tubular or rod . form, wherein at least one of said blades is formed with a cutting edge comprising a piercing point or -~region having on each side portions which trail the leading extremity of the piercing point or region considered in the direction of cutting, whereby in operation after initial piercing of the material to be cut, and on continued cutting, the incision made by the piercing point or region increases away from the pierced region towards the sides of the material being cut.
Preferably the blades are pivotally mounted as a co-operating pair in scissors-fashion on a support member and are operable by means of a ram connected to said blades by links. It is of manufac~uring and economic advantage to make the blades of the pair identical to each other~
BRIEF DESCRIPTION OF DRAWINGS
The invention will now be described by way of example with reference to the accompanyin~ drawing in ~hich:
FIGURE lA and lB show an eleva~ion of the cut~er, FIGURE 2A and 2B show an under plan view, FIGURE 3 is an end elevation, and FIGURE 4 shows a cut~er head only with the cutter blades in the closed position at the end of a cutting operation, and FIGURE 5 shows a construction in which the blades are integrally formed with handles for manned opera~ion.
DESCRIPTION OF PREFERRED EMBODIME~T
The hydraulic tube cukter shown in khe drawings is constructed using a hydraulic ram assembly of the kind used for a vehicle rescue pillar cutter, adapted by means of the present invention~ The ram assembly 9 .~2g)Z~7~
comprises a blade support me~ber or head 10 carried and secured by a thread on one end o~ a ram cylinder 12, at the other end of which is a valve assernbly 13 which can be actuated by a lever 14. A supply o~ hydraulic fluid is provided through flexible hoses 15, 16. On actuation of the valve fluid pressureJ which when khe tool is not in use passes from one hose to the other through a communicating aperture (not shown) wlthin the valve assembly, is applied to the piston (not shown) of the ram assembly. A rod 17 of the ram assembly moves within the cylinder and thus actuates a pair of cutter blades 18, l9 pivotally mounted on a bolt 20~ located in aperture 20a by way of connecting links 217 22 mounted on the rod by a common pin 23. Pivot pins 24 located within apertures 24a in the blade connect the links 21, 22 to the blades l8, l9.
The aperture 24a of each blade is disposed on an axis parallel at the axis of the pivot bolt 20, ~he axes of the two apertures in each blade being disposed on a line arranged at an angle of between 90 and 180 degrees to a line from the pivot axis ko said piercing point such as to enable maximum moments of force ~o be achieved on operation of the links by the ram.
For the sake of comparison cutter blades o~ a known cutter are shown in chain lines in Figure l. It will be seen from the drawing that the known blades each comprise a cutting edge which is formed as part of a ~
. ., . ,;. . ,.. , ., . . ~ , , . , . . - .:.
i~2~
circle and terminates in a b~lunt corner. The tips at the distal ends of the bladcs comprise flat faces.
However, in ~he present inven~ion the blades are each formed with a cutting edge 25 having a piercing point (or short region) 26 having on each s:ide portions 27, 28 which trail the leading extremity of the piercing point 26 considered in the direction of cutting shown by the arrow A. The piercing point,is positioned substantially mid-way between the pivot bolt 20 and the furthermost extremity 29 of the portion 28.
The portion 27 comprises a straight part 27a and a circular part 27b. The edge of the straight portion 28 and the tangent to the circular portion 27b at the piercing point may enclose an angle ~C of between 60 and 140 degrees but is preferably 100 degrees. The cutting edge 25 is formed by grinding the blade edge at an angle of between 30 degrees and 45 degrees to khe major surfaces of the blade, By providing a cutting edge formed with a piercing point and two trailirlg cutting edges ~or in other words, cutting edges which sweep back from the piercing point) a pipe such as an- exhausk pipe can be efficiently cut. The blades are positioned prior to cutting preferably across the diameter of the pipe.
First the piercing point enters the opposite walls o~
the pipe so that an incision is made. As the pressure is applied to the blades the incision grows towards the ~Zt~Z7t7~
side of ~he now partially fla~tened pipe.
As explained above, if as in the prior art, flattening takes place prior to cuttin~, a large force is required to effec~ the initial cuk due to the ~hick bent over double edge and connecting bend. The important aspect to be considered in the present invention is the initial prèssure needed to make the cut at the centre OI the material to be cut which cut once started needs no increased pressure to maintain the progress of the shear effeck~
Accordingly, an improved cu~ting effect is obtained with a less power (and less heavy) ram unit than ~ould otherwise be required.
The reduction in force need is also achieved by the positioning of the plercing point whereby khe rnoment of force required for the incision is reduced. If the piercing point were positioned too far from the fulcrum of the blade a greater force would be required.
However, by reducing the distance x in relation ko the distance ~ the initial cutking force required is reducedO
By so reducing the force required for cutting exhaust pipes the blades may be operated manually i.e., the blades of the present inven~ion may replace those used in known bolk croppers. The hlades in this construction may be pivotally mounted on one axis or alternatively on axes offset from each other.
~Z~7~
In the arrangement shown ln Figure 5 blades 34, 35 having cutting edges of the kind described in the above examples, are integrally forrned with handles 31, 37 for manual operation. The two blades are pivoted together on a common axis by a pivot pin 38. The handles are preferably provided with stops 39 to protect the operator's hands.
BACKGROUND TO THE X~JVENTION - -This invention relates to apparatus for shearing material in flat, tubular or rod ~orrn and more especially but not solely for exhaust pipes.
For the purpose of the replacement ~f exhaust sys~ems in motor vehicles the need has arisen for speedy removal of exhausk pipes prior to fitting replacement parts. The pipes are generally from 31 mm.
to 58 mm. in diameter having a wall thickness of 16 S.W.G.
STATEMENT OF PRIOR ARI
~ ttempts were made to use well known hand operated cutting implements often termed bolk-croppers~ These were found to be unsuccessful since after the initial difficulty of grippin~ the pipe was overcome the latter merely flattened, presenting to the cropper blades a double wall thickness joined by a bend which resisted shearing. Shears having park-circular cutting edges were found ~o be similarly unsatisfactory.
~ It was evident that insufficient power was being transmitted to khe cutter blades to overcome the resistance offered by the fold at the initiakion of the cutting operation. Attention was, therefore, turned to hydraulic power. Two devices were considered namely a cable cutter and a pillar cutter for emergency use on vehicles. Whilsk these were amply capable of cutting ., ' ~
7~
through exhaust pipes they were extremely heavy pieces of equipment quite unsuita~le for easy manipulation by a mechanic working beneath a vehicle.
OBJECT OF THE INVENTION
An object of the invention is to provide cu~ter blades which permit ease o~ use of a hand held tool ~or the purpose of cutting sheet metal9 especially exhaust pipes of motor vehicles.
The inventor decided to approach the problem from the point of vie~ of blade design~ It occurred to him that if the blades could be made to pierce the tube less power would be needed to effect a shearing action~
S~MMARY OF THE INVENTION
According to the invention there is provided a pair of cutter blades for relative movement between each other for cutting sheet metal in flat, tubular or rod . form, wherein at least one of said blades is formed with a cutting edge comprising a piercing point or -~region having on each side portions which trail the leading extremity of the piercing point or region considered in the direction of cutting, whereby in operation after initial piercing of the material to be cut, and on continued cutting, the incision made by the piercing point or region increases away from the pierced region towards the sides of the material being cut.
Preferably the blades are pivotally mounted as a co-operating pair in scissors-fashion on a support member and are operable by means of a ram connected to said blades by links. It is of manufac~uring and economic advantage to make the blades of the pair identical to each other~
BRIEF DESCRIPTION OF DRAWINGS
The invention will now be described by way of example with reference to the accompanyin~ drawing in ~hich:
FIGURE lA and lB show an eleva~ion of the cut~er, FIGURE 2A and 2B show an under plan view, FIGURE 3 is an end elevation, and FIGURE 4 shows a cut~er head only with the cutter blades in the closed position at the end of a cutting operation, and FIGURE 5 shows a construction in which the blades are integrally formed with handles for manned opera~ion.
DESCRIPTION OF PREFERRED EMBODIME~T
The hydraulic tube cukter shown in khe drawings is constructed using a hydraulic ram assembly of the kind used for a vehicle rescue pillar cutter, adapted by means of the present invention~ The ram assembly 9 .~2g)Z~7~
comprises a blade support me~ber or head 10 carried and secured by a thread on one end o~ a ram cylinder 12, at the other end of which is a valve assernbly 13 which can be actuated by a lever 14. A supply o~ hydraulic fluid is provided through flexible hoses 15, 16. On actuation of the valve fluid pressureJ which when khe tool is not in use passes from one hose to the other through a communicating aperture (not shown) wlthin the valve assembly, is applied to the piston (not shown) of the ram assembly. A rod 17 of the ram assembly moves within the cylinder and thus actuates a pair of cutter blades 18, l9 pivotally mounted on a bolt 20~ located in aperture 20a by way of connecting links 217 22 mounted on the rod by a common pin 23. Pivot pins 24 located within apertures 24a in the blade connect the links 21, 22 to the blades l8, l9.
The aperture 24a of each blade is disposed on an axis parallel at the axis of the pivot bolt 20, ~he axes of the two apertures in each blade being disposed on a line arranged at an angle of between 90 and 180 degrees to a line from the pivot axis ko said piercing point such as to enable maximum moments of force ~o be achieved on operation of the links by the ram.
For the sake of comparison cutter blades o~ a known cutter are shown in chain lines in Figure l. It will be seen from the drawing that the known blades each comprise a cutting edge which is formed as part of a ~
. ., . ,;. . ,.. , ., . . ~ , , . , . . - .:.
i~2~
circle and terminates in a b~lunt corner. The tips at the distal ends of the bladcs comprise flat faces.
However, in ~he present inven~ion the blades are each formed with a cutting edge 25 having a piercing point (or short region) 26 having on each s:ide portions 27, 28 which trail the leading extremity of the piercing point 26 considered in the direction of cutting shown by the arrow A. The piercing point,is positioned substantially mid-way between the pivot bolt 20 and the furthermost extremity 29 of the portion 28.
The portion 27 comprises a straight part 27a and a circular part 27b. The edge of the straight portion 28 and the tangent to the circular portion 27b at the piercing point may enclose an angle ~C of between 60 and 140 degrees but is preferably 100 degrees. The cutting edge 25 is formed by grinding the blade edge at an angle of between 30 degrees and 45 degrees to khe major surfaces of the blade, By providing a cutting edge formed with a piercing point and two trailirlg cutting edges ~or in other words, cutting edges which sweep back from the piercing point) a pipe such as an- exhausk pipe can be efficiently cut. The blades are positioned prior to cutting preferably across the diameter of the pipe.
First the piercing point enters the opposite walls o~
the pipe so that an incision is made. As the pressure is applied to the blades the incision grows towards the ~Zt~Z7t7~
side of ~he now partially fla~tened pipe.
As explained above, if as in the prior art, flattening takes place prior to cuttin~, a large force is required to effec~ the initial cuk due to the ~hick bent over double edge and connecting bend. The important aspect to be considered in the present invention is the initial prèssure needed to make the cut at the centre OI the material to be cut which cut once started needs no increased pressure to maintain the progress of the shear effeck~
Accordingly, an improved cu~ting effect is obtained with a less power (and less heavy) ram unit than ~ould otherwise be required.
The reduction in force need is also achieved by the positioning of the plercing point whereby khe rnoment of force required for the incision is reduced. If the piercing point were positioned too far from the fulcrum of the blade a greater force would be required.
However, by reducing the distance x in relation ko the distance ~ the initial cutking force required is reducedO
By so reducing the force required for cutting exhaust pipes the blades may be operated manually i.e., the blades of the present inven~ion may replace those used in known bolk croppers. The hlades in this construction may be pivotally mounted on one axis or alternatively on axes offset from each other.
~Z~7~
In the arrangement shown ln Figure 5 blades 34, 35 having cutting edges of the kind described in the above examples, are integrally forrned with handles 31, 37 for manual operation. The two blades are pivoted together on a common axis by a pivot pin 38. The handles are preferably provided with stops 39 to protect the operator's hands.
Claims (16)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A pair of cutter blades for relative movement between each other for cutting sheet metal in flat, tubular or rod form, wherein each blade is formed with a cutting edge comprising a piercing region in the form of a point and having on each side portions which trail the leading extremity of the piercing point considered in the direction of cutting, each blade having an aperture on an axis about which the blade can pivot, the portion of each cutting edge on the side of the piercing point remote from the pivot aperture being straight, whereby in operation after initial piercing of the material to be cut, and on continued cutting, the incision made by the piercing point increases away from the piercing region towards the sides of the material being cut.
2. Cutter blades according to claim 1, wherein the portion of each cutting edge between the piercing point and the pivot aperture includes a substantially arcuate part nearest the piercing point or region.
3. Cutter blades according to claim 2, wherein the arcuate part is part circular and merges with a straight part which extends tangentially to the circle containing said arcuate part.
4. Cutter blades according to claim 3, wherein the edge of the straight portion and the tangent to the arcuate part at the piercing point enclose an angle (?) of between 60° and 140°.
5. Cutter blades according to claim 1, wherein the cutting edge is raked at an angle of between 30° and 45°.
6. Cutter blades according to claim 1, wherein each blade has a second aperture on an axis parallel to the pivotal axis, for the attachment of an operating linkage, the two axes being disposed on a line arranged at an angle of between 90° and 180°
to a line from said pivot axis to said piercing point such as to enable maximum moments of force to be achieved when said linkage is operated.
to a line from said pivot axis to said piercing point such as to enable maximum moments of force to be achieved when said linkage is operated.
7. Cutter blades according to claim 1, wherein the two blades are identical.
8. Cutter blades according to claim 1, wherein the blades are pivotally connected together on a common axis.
9. Cutter blades according to claim 1, wherein handles are integrally formed with the blades, which blades are connected together on a common axis.
10. In a cutting tool, for cutting hollow tubular members of predetermined annular wall thickness and predetermined diameter, comprising a pair of planar opposed blade bodies, pivotally connected at a common blade pivot for relative movement with respect to each other between an open position and a closed position and receivable of an object to be cut therebetween in said open position, each said blade body comprising a substantially planar body having an outer extremity remote from said common blade pivot, the improvement comprising:
tube shearing means, on each of said blade bodies, for shearing the annular wall of the tubular member, said tube shearing means comprising a first cutting edge and a second cutting edge disposed to intersect and form an angle therebetween, said first cutting edge extending from proximate said common blade pivot to said intersection and comprising a circular portion nearest said intersection which merges tangentially with a straight portion proximate said common blade pivot, said second cutting edge extending from said intersection to said outer extremity in a straight line, each of said circular portions having a center of curvature which is closer than the other center of curvature to its respective edge when said blade bodies are in said open position;
tube piercing means, on each of said blade bodies, for simultaneously piercing the annular wall of the tubular member at two diametrically opposed points, said tube piercing means movable into piercing engagement with said tubular member at said diametrically opposed points, said tube piercing means comprising a point formed by the apex of the angle between said first and second cutting edges;
said tube shearing means cooperating with said tube piercing means to shear the tube wall on opposite sides of each of said diametrically opposed points, whereby in operation after initial piercing of the annular wall of the tubular member, and on continued cutting, the incisions made by the tube piercing means each increase away from the initial pierced point toward the sides of the tubular members;
actuating means for pivotally moving said blade bodies relative to one another about said common blade pivot, said actuating means comprising a hydraulic cylinder having an axis, a piston member with said hydraulic cylinder, said piston member axially movable within said cylinder, two rigid links pivotally connected to respective blade bodies of said pair of opposed blade bodies, means for fixedly connecting said common blade pivot to said hydraulic cylinder, means for pivotally connecting said two rigid links to a common link pivot on said piston member. whereby axial movement of said piston member causes relative movement of said blade bodies with respect to each other about said common blade pivot;
said pair of opposed blade bodies disposed in at least partially overlying relationship proximate said common blade pivot, whereby in said open position, said outer extremities are spaced apart from one another, and, in said closed position, said outer extremities overlap one another, and, as said blade bodies move toward one another, said tube piercing means come into overlapping relation before said outer extremities.
tube shearing means, on each of said blade bodies, for shearing the annular wall of the tubular member, said tube shearing means comprising a first cutting edge and a second cutting edge disposed to intersect and form an angle therebetween, said first cutting edge extending from proximate said common blade pivot to said intersection and comprising a circular portion nearest said intersection which merges tangentially with a straight portion proximate said common blade pivot, said second cutting edge extending from said intersection to said outer extremity in a straight line, each of said circular portions having a center of curvature which is closer than the other center of curvature to its respective edge when said blade bodies are in said open position;
tube piercing means, on each of said blade bodies, for simultaneously piercing the annular wall of the tubular member at two diametrically opposed points, said tube piercing means movable into piercing engagement with said tubular member at said diametrically opposed points, said tube piercing means comprising a point formed by the apex of the angle between said first and second cutting edges;
said tube shearing means cooperating with said tube piercing means to shear the tube wall on opposite sides of each of said diametrically opposed points, whereby in operation after initial piercing of the annular wall of the tubular member, and on continued cutting, the incisions made by the tube piercing means each increase away from the initial pierced point toward the sides of the tubular members;
actuating means for pivotally moving said blade bodies relative to one another about said common blade pivot, said actuating means comprising a hydraulic cylinder having an axis, a piston member with said hydraulic cylinder, said piston member axially movable within said cylinder, two rigid links pivotally connected to respective blade bodies of said pair of opposed blade bodies, means for fixedly connecting said common blade pivot to said hydraulic cylinder, means for pivotally connecting said two rigid links to a common link pivot on said piston member. whereby axial movement of said piston member causes relative movement of said blade bodies with respect to each other about said common blade pivot;
said pair of opposed blade bodies disposed in at least partially overlying relationship proximate said common blade pivot, whereby in said open position, said outer extremities are spaced apart from one another, and, in said closed position, said outer extremities overlap one another, and, as said blade bodies move toward one another, said tube piercing means come into overlapping relation before said outer extremities.
11. The cutting tool as claimed in claim 10, wherein said second cutting edge and the tangent, extending into the blade body, to the circular portion of the first cutting edge, at said intersection, form an angle between 60° and 140°.
12. The cutting tool as claimed in claim 10, wherein each cutting edge is raked at an angle of from 30° to 45° to the plane of the blade body.
13. In a cutting tool, for cutting hollow tubular members of predetermined annular wall thickness and predetermined diameter, comprising a pair of planar opposed blade bodies, pivotally connected at a common blade pivot for relative movement with respect to each other between an open position and a closed position and receivable of an object to be cut therebetween in said open position, each said blade body comprising a substantially planar body having an outer extremity remote from said common blade pivot, the improvement comprising:
tube shearing means, on each of said blade bodies, for shearing the annular wall of the tubular member, said tube shearing means comprising a first cutting edge and a second cutting edge disposed to intersect and form an angle therebetween, said first cutting edge extending from proximate said common blade pivot to said intersection and comprising a circular portion nearest said intersection which merges tangentially with a straight portion proximate said common blade pivot, said second cutting edge extending from said intersection to said outer extremity in a straight line, each of said circular portions having a center of curvature which is closer than the other center of curvature to its respective edge when said blade bodies are in said open position;
tube piercing means, on each of said blade bodies, for simultaneously piercing the annular wall of the tubular member at two diametrically opposed points, said tube piercing means movable into piercing engagement with said tubular member at said diametrically opposed points, said tube piercing means comprising a point formed by the apex of the angle between said first and second cutting edges;
said tube shearing means cooperating with said tube piercing means to shear the tube wall on opposite sides of each of said diametrically opposed points. whereby in operation after initial piercing of the annular wall of the tubular member, and on continued cutting, the incisions made by the tube piercing means each increase away from the initial pierced point toward the sides of the tubular member;
actuating means for pivotally moving said blade bodies relative to one another about said common blade pivot;
said pair of opposed blade bodies disposed in at least partially overlying relationship proximate said common blade pivot, whereby in said open position, said outer extremities are spaced apart from one another, and, in said closed position, said outer extremities overlap one another, and, as said blade bodies move toward one another, said tube piercing means come into overlapping relation before said outer extremities.
tube shearing means, on each of said blade bodies, for shearing the annular wall of the tubular member, said tube shearing means comprising a first cutting edge and a second cutting edge disposed to intersect and form an angle therebetween, said first cutting edge extending from proximate said common blade pivot to said intersection and comprising a circular portion nearest said intersection which merges tangentially with a straight portion proximate said common blade pivot, said second cutting edge extending from said intersection to said outer extremity in a straight line, each of said circular portions having a center of curvature which is closer than the other center of curvature to its respective edge when said blade bodies are in said open position;
tube piercing means, on each of said blade bodies, for simultaneously piercing the annular wall of the tubular member at two diametrically opposed points, said tube piercing means movable into piercing engagement with said tubular member at said diametrically opposed points, said tube piercing means comprising a point formed by the apex of the angle between said first and second cutting edges;
said tube shearing means cooperating with said tube piercing means to shear the tube wall on opposite sides of each of said diametrically opposed points. whereby in operation after initial piercing of the annular wall of the tubular member, and on continued cutting, the incisions made by the tube piercing means each increase away from the initial pierced point toward the sides of the tubular member;
actuating means for pivotally moving said blade bodies relative to one another about said common blade pivot;
said pair of opposed blade bodies disposed in at least partially overlying relationship proximate said common blade pivot, whereby in said open position, said outer extremities are spaced apart from one another, and, in said closed position, said outer extremities overlap one another, and, as said blade bodies move toward one another, said tube piercing means come into overlapping relation before said outer extremities.
14. The cutting tool as claimed in claim 13, wherein said second cutting edge and the tangent, extending into the blade body, to the circular portion of the first cutting edge, at said intersection form an angle between 60° and 140°.
15. The cutting tool as claimed in claim 13, wherein each cutting edge is raked at an angle of from 30° to 45° to the plane of the blade body.
16. The cutting tool as claimed in claim 13, wherein said actuating means comprises, of each blade body, a handle portion located on the opposite side of said common blade pivot from said outer extremity, said handle portion adapted for manual operation of the cutting tool.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8130277 | 1981-10-07 | ||
| GB8130277 | 1981-10-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1202772A true CA1202772A (en) | 1986-04-08 |
Family
ID=10525004
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000412525A Expired CA1202772A (en) | 1981-10-07 | 1982-09-30 | Cutting apparatus |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4549349A (en) |
| EP (1) | EP0077616B1 (en) |
| AU (1) | AU561397B2 (en) |
| CA (1) | CA1202772A (en) |
| DE (1) | DE3264128D1 (en) |
| ES (1) | ES277020Y (en) |
| ZA (1) | ZA827113B (en) |
Families Citing this family (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5125158A (en) * | 1989-02-23 | 1992-06-30 | Casebolt David R | Hand manipulated portable cutting and shearing tool with spreader adaptors |
| US5058272A (en) * | 1990-04-18 | 1991-10-22 | Mississippi Power Company | Tool apparatus for applying large forces |
| CA2048780C (en) * | 1991-08-08 | 1997-12-16 | Edward Joseph Schartinger | Blade for cutting cylindrical structures |
| US5243761A (en) * | 1992-03-18 | 1993-09-14 | Hale Fire Pump Company | Portable rescue tool |
| AT403491B (en) * | 1996-02-15 | 1998-02-25 | Wimmer Alois Ing | CONCRETE CRUSHERS with CUTTING SHEARS |
| FR2753120B1 (en) * | 1996-09-10 | 1998-12-11 | Virax Sa | TUBE CUTTER CLIP DEVICE FOR CROSS-CUTTING A PLASTIC TUBE |
| US6112415A (en) * | 1999-01-15 | 2000-09-05 | Gs Metals Corp. | Hookbill wire cutter |
| DE10313827A1 (en) * | 2003-03-21 | 2004-09-30 | REMS-WERK Christian Föll und Söhne GmbH & Co. | Separating device for workpieces, such as rods, bolts and the like, in particular for threaded rods |
| US20070145171A1 (en) * | 2005-12-23 | 2007-06-28 | The Stanley Works | Rebar cutting shears |
| US7367396B2 (en) * | 2006-04-25 | 2008-05-06 | Varco I/P, Inc. | Blowout preventers and methods of use |
| US8720565B2 (en) * | 2006-04-25 | 2014-05-13 | National Oilwell Varco, L.P. | Tubular severing system and method of using same |
| US8424607B2 (en) | 2006-04-25 | 2013-04-23 | National Oilwell Varco, L.P. | System and method for severing a tubular |
| US8720564B2 (en) * | 2006-04-25 | 2014-05-13 | National Oilwell Varco, L.P. | Tubular severing system and method of using same |
| US20080000091A1 (en) * | 2006-06-29 | 2008-01-03 | Toho Koki Co., Ltd. | Threaded Rod Cutter |
| US20080045128A1 (en) * | 2006-08-17 | 2008-02-21 | Trueit Gerald D | Door skin cutter |
| US9486864B2 (en) | 2007-07-03 | 2016-11-08 | Milwaukee Electric Tool Corporation | Pipe cutter |
| GB2464850B (en) * | 2007-07-03 | 2012-04-04 | Milwaukee Electric Tool Corp | Pipe cutter |
| US8162046B2 (en) | 2010-08-17 | 2012-04-24 | T-3 Property Holdings, Inc. | Blowout preventer with shearing blades |
| WO2014130703A2 (en) | 2013-02-21 | 2014-08-28 | National Oilwell Varco, L.P. | Blowout preventer monitoring system and method of using same |
| EP3600742A4 (en) | 2017-03-24 | 2021-04-14 | Milwaukee Electric Tool Corporation | Shear |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2249515A (en) * | 1940-12-10 | 1941-07-15 | Nina R Carroll | Shear |
| US2794250A (en) * | 1953-05-21 | 1957-06-04 | Thomas & Betts Corp | Cabel cutter |
| US2791028A (en) * | 1956-05-10 | 1957-05-07 | Bidin Peter | Hydraulically operated hand tools |
| US2870538A (en) * | 1958-03-11 | 1959-01-27 | J T Henry Mfg Co Inc | Cable cutter |
| US3012321A (en) * | 1960-06-01 | 1961-12-12 | J T Henry Mfg Co Inc | Cable cutter |
| US3624903A (en) * | 1969-08-26 | 1971-12-07 | James W Tibbet | Cutter for energized power lines |
| DE2745114C2 (en) * | 1977-10-07 | 1983-01-05 | Baudat E. Wolter KG, 7941 Dürmentingen | Portable scissors, especially for cutting cables |
| DE2910544A1 (en) * | 1979-03-17 | 1980-09-25 | Wolter Baudat E Kg | SCISSORS, IN PARTICULAR CABLE CUTTERS |
| DE3028370A1 (en) * | 1980-07-26 | 1982-02-25 | Frieseke & Hoepfner Gmbh, 8520 Erlangen | Portable hydraulic rod cutter - has pincer action jaws with blades of specified wedge shape and stop preventing mutual blade contact |
| US4392263A (en) * | 1981-02-02 | 1983-07-12 | Amoroso Michael J | Portable rescue tool |
-
1982
- 1982-09-27 AU AU88759/82A patent/AU561397B2/en not_active Ceased
- 1982-09-29 ZA ZA827113A patent/ZA827113B/en unknown
- 1982-09-30 CA CA000412525A patent/CA1202772A/en not_active Expired
- 1982-09-30 DE DE8282305202T patent/DE3264128D1/en not_active Expired
- 1982-09-30 EP EP82305202A patent/EP0077616B1/en not_active Expired
- 1982-10-06 ES ES1982277020U patent/ES277020Y/en not_active Expired
-
1984
- 1984-11-14 US US06/671,435 patent/US4549349A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| AU8875982A (en) | 1983-04-14 |
| AU561397B2 (en) | 1987-05-07 |
| ES277020Y (en) | 1985-02-01 |
| EP0077616A2 (en) | 1983-04-27 |
| EP0077616A3 (en) | 1983-08-03 |
| EP0077616B1 (en) | 1985-06-12 |
| DE3264128D1 (en) | 1985-07-18 |
| US4549349A (en) | 1985-10-29 |
| ES277020U (en) | 1984-07-01 |
| ZA827113B (en) | 1983-08-31 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |