Patent Application
20100146795
The present invention relates to cutting tools and, more particularly, to serrated pipe cutters having a pair of pivoted handles, one of which carries a serrated blade and the other of which supports the article to be cut.
Cutting tools, particularly handled serrated pipe cutters, have many uses. Conduits and other tubular articles, such as pipes, are often manufactured in bulk and handled cutting tools are often employed to cut the bulk length of manufactured conduit into smaller lengths.
Known types of handled cutting tools include pipe cutters which carry a straight blade. One drawback associated with cutters of this type is that, when placed in initial contact with an article to be cut, the force applied to the cutting tool is spread along the entire edge of the straight blade, thereby reducing the pressure applied on the article; as such, an increased force is required to initiate the cut into the article. Not only is this increased force burdensome for the user, it presents a further drawback of potentially resulting in deformation of the article in the area surrounding the applied force.
Other types of cutting tools include handled cutting tools which carry a blade that is of a constant thickness. One drawback associated with cutting tools of this variety is that, as the blade passes through the article, its lateral sides remain in constant contact with the interior material of the article. A frictional force thereby is applied to the blade from the article, requiring an increased force to be applied during execution of the cut.
Other types of known pipe cutters include blades with a jagged edge, or saw tooth, blade. This type of blade cuts in a lateral motion, by pushing and pulling the blade through the article to be cut in a direction perpendicular to the longitudinal axis of the article. One drawback associated with cutting tools of this kind is that they do not include a support system for the article, thereby requiring the user to support the article separately in a cumbersome fashion as the cut is made. Another drawback associated with cutting tools of this nature is that they can only be used in an area that provides sufficient space for the user to effect the lateral-motion cut.
Accordingly, it is an object of the present invention to overcome one or more of the above-described drawbacks and/or disadvantages of the prior art.
In accordance with a first aspect, the present invention is directed to a serrated pipe cutter comprising first and second handles that are coupled together and movable relative to each other. The first or upper handle includes a jaw for engaging one side of the pipe to be cut, and the second or lower handle includes a serrated blade for engaging the opposite side of the pipe relative to the jaw and for cutting the pipe against the jaw. The serrated blade defines a back edge and an elongated cutting edge located on an opposite side of the blade relative to the back edge. The blade further comprises a first side edge extending between the back and cutting edges of the blade, a second side edge located on an opposite side of the blade relative to the first side edge, and a blade body extending between the first, second, back and cutting edges of the blade. The blade further includes faceted surfaces located on opposite sides of the blade relative to each other and tapering inwardly in a direction from the body toward the cutting edge of the blade. The elongated cutting edge defines along one side thereof a plurality of serrations that are axially spaced relative to each other along the cutting edge. The opposite side of the cutting edge relative to the serrations is substantially planar, and defines a plurality of axially spaced, relatively shallow recesses at the cutting edge, wherein each recess is defined by a respective serration formed on the opposite side of the blade. Each serration defines a curvilinear serration boundary between the respective serration and a contiguous faceted surface, a substantially concave serration surface located within the curvilinear serration boundary and tapering inwardly in a direction from the body toward the cutting edge, and an axially-extending serration cutting edge.
The elongated cutting edge of the blade further defines a plurality of cutting tips extending between adjacent serrations. Each cutting tip defines an axially extending cutting tip edge, and each serration cutting edge is recessed inwardly on the elongated cutting edge relative to at least one contiguous cutting tip edge. The second or upper handle includes on the distal end thereof a jaw defining a substantially concave recess for receiving therein the pipe to be cut. At least one of the first and second handles is movable relative to the other to engage the pipe with the elongated cutting edge of the blade and cut the pipe.
In some embodiments, the serrated cutting edge defines a plurality of substantially linear cutting edge surfaces, wherein at least one linear cutting edge surface is angled inwardly toward the body at an acute angle within the range of about 8° to about 12°. In one such embodiment, each of the serrated cutting edges defines two substantially linear cutting edge surfaces located on opposite sides of the serrated cutting edge relative to each other and angled inwardly toward the body, and at least one substantially linear cutting edge extending between the two angled cutting edges.
In some embodiments, the serration boundaries each define an apex and a pair of substantially symmetrical, curvilinear boundary lines, each extending on opposite sides of the apex relative to each other between the apex and a respective contiguous cutting tip. In one such embodiment, each serration boundary is substantially elliptical shaped.
In some embodiments, the serrations are substantially equally spaced relative to each other along the elongated cutting edge. In one such embodiment, the distance between each serration apex and contiguous cutting tip edge is within the range of about 3/100 inch to about 9/100 inch. In another embodiment, at least a portion of each serration edge is substantially curvilinear and/or substantially straight.
In some embodiments, the cutting tips each define a substantially straight axially extending cutting tip edge and a pair of faceted surfaces on opposite sides of the cutting tip relative to each other and tapering inwardly toward the axially extending cutting tip edge. In one such embodiment, the faceted surfaces of each cutting tip taper inwardly relative to the respective side of the blade body at an angle within the range of about 20° to about 30°.
In some embodiments, the serration cutting edges each define an axial length within the range of about 4/100 inch and about 9/100 inch, and a plurality of the cutting tip edges each define an axial length within the range of about 3/100 inch and about 8/100 inch. In some embodiments, each substantially concave serration surface is defined by a radius within the range of about 2 inches to about 4 inches.
In some embodiments, a plurality of the cutting tips each define a first substantially linear cutting tip boundary between the respective cutting tip and a contiguous faceted surface, a second substantially linear cutting tip boundary between the cutting tip and an adjacent serration, and a third substantially linear cutting tip boundary between the cutting tip and an adjacent serration opposite the second cutting tip boundary Faceted surfaces are formed on opposites sides of the cutting tip relative to each other, and on the serrated side of the blade, the faceted surfaces are formed within the first and second boundaries and taper inwardly in the direction from the body toward the cutting edge. In one embodiment, at least a portion of each cutting tip edge is substantially curvilinear and/or substantially straight.
In some embodiments, the pipe cutter further comprises a locking mechanism releasably engageable with the handles. The locking mechanism defines an open state, wherein the locking mechanism is disengaged from the handles and allows movement of the handles relative to one another between an open position and a closed position, and a locked state, wherein the locking mechanism engages at least one of the handles to prevent movement of the handles relative to one another.
In accordance with another aspect, the present invention is directed to a serrated pipe cutter comprising first means for manually gripping and second means mounted on the first means for cutting a pipe. The second means defines an axially elongated cutting edge including a plurality of third means for serrating the cutting edge that are axially spaced relative to each other along the cutting edge. The second means also defines a plurality of fourth means for forming non-serrated cutting edge segments that are axially spaced relative to each other along the cutting edge. Each of a plurality of fourth means are located between respective third means, and the third means are recessed inwardly on the elongated cutting edge relative to adjacent fourth means. The pipe cutter further comprises fifth means coupled to the first means for supporting the pipe and for manually gripping. At least one of the first and fifth means is manually movable relative to the other for driving the elongated cutting edge of the second means into engagement with the pipe to cut the pipe.
In one embodiment, the first means is a first handle, the second means is a blade, each third means is a serration axially spaced relative to an adjacent serration, and each fourth means is a cutting tip defining a substantially linear cutting edge segment and a pair of faceted surfaces formed on opposite sides of the cutting tip relative to each other. Each serration defines a boundary having an apex and curvilinear boundary lines extending substantially symmetrically between the apex and the cutting edge, a substantially concave serration surface formed within the boundary, and a serration cutting edge. Each pair of faceted surfaces tapers inwardly toward the respective linear cutting edge, and each serration cutting edge is recessed inwardly relative to at least one contiguous linear cutting edge segment.
In one embodiment, the pipe cutter further comprises sixth means coupled to at least one of the first means and fifth means for releasably engaging the first means and/or the fifth means and preventing relative movement of the first means and fifth means. In one embodiment, the sixth means is a locking mechanism that defines a locked state wherein the locking mechanism engages at least one of the first and second handles to prevent movement of the first handle relative to the second handle, and an open state wherein the locking mechanism disengages at least one of the first and second handles to allow movement of the first handle relative to the second handle between an open position and a closed position.
In accordance with another aspect, the present invention is directed to a serrated blade defining an elongated serrated cutting edge and mountable within a serrated pipe cutter including a first handle, a second handle coupled to the first handle, and including a jaw defining a substantially concave recess for receiving therein a pipe to be cut. The first and/or second handle is movable relative to the other to engage a pipe with the elongated cutting edge of the blade and cut the pipe. The serrated blade defines a back edge, an elongated cutting edge located on an opposite side of the blade relative to the back edge, a first side edge extending between the back and cutting edges of the blade, a second side edge located on an opposite side of the blade relative to the first side edge, a blade body extending between the first, second, back and cutting edges of the blade, and faceted surfaces located on opposite sides of the blade relative to each other and tapering inwardly in a direction from the body toward the cutting edge of the blade. The elongated cutting edge defines a plurality of serrations axially spaced relative to each other along one side of the blade, and a substantially planar surface located on an opposite side of the cutting edge relative to the serrations. Each serration defines a curvilinear serration boundary between the respective serration and a contiguous faceted surface, a substantially concave serration surface located within the curvilinear serration boundary and tapering inwardly in a direction from the body toward the cutting edge, and an axially-extending serration cutting edge. The elongated cutting edge of the blade further defines a plurality of cutting tips extending between adjacent serrations. Each cutting tip defines an axially extending cutting tip edge, and each serration cutting edge is recessed inwardly on the elongated cutting edge relative to at least one contiguous cutting tip edge.
One advantage of the present invention is that the serrations along the cutting edge improve cutting performance by providing additional cutting points and by effectively increasing the length of the cutting edge in comparison to straight edge blades. Further, the serrations improve cutting edge wear, as the additional cutting points initiate the cut, which effectively reduces the amount of force applied to the sharpened recessed curves that continue the cut.
Another advantage of the currently preferred embodiments of the present invention is that the substantially concave recess of the jaw supports the pipe, allowing for easier execution of the cut. Another advantage of the currently preferred embodiment of the present invention is that the slot formed within the jaw receives at least a portion of the blade in the second position, thereby ensuring that a clean cut is made through the pipe. Yet another advantage of the currently preferred embodiments of the present invention is that, as the cut is made via a downwardly applied force, and not by a sawing action, the tool may be used in a tight or narrow space. Another advantage of the currently preferred embodiments of the present invention is that the locking mechanism is engageable to ensure that the two handles remain closed when desired, providing easy mobility and safe storage of the pipe cutter.
Other advantages of the present invention, and/or of the currently preferred embodiments thereof, will become more readily apparent in view of the following detailed description of the currently preferred embodiments and accompanying drawings.
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Each serration cutting edge 40 intersects at one end thereof the respective second linear boundary 46 and intersects at the other end thereof the respective third linear boundary 48. In the illustrated embodiment, the linear distance D3 between the two intersection points is preferably within the range of about 4/100 inch to about 9/100 inch. As can be seen, the serration boundary 36 also intersects the adjacent second linear boundary 46 and third linear boundary 48. In the illustrated embodiment, the linear distance D4 between the two intersection points is preferably within the range of about 6/100 inch to about 12/100 inch. Each cutting tip 34 also includes a pair of cutting tip surfaces 50 located on opposite sides of the body 28 relative to each other, which taper inwardly toward the cutting edge 26. In the illustrated embodiment, each cutting surface 50 is substantially planar. In the currently preferred embodiment, each cutting surface 50 tapers inwardly relative to the first side 20 of the blade 18 at an angle within the range of about 24 degrees to about 26 degrees, and preferably about 25 degrees. However, as may be recognized by those of ordinary skill in the pertinent art based on the teachings herein, these dimensions and angles are only exemplary and the cutting surface 50 may take any dimension or shape that is known or becomes known. For example, the cutting surfaces 50 may be substantially concave.
Each cutting tip 34 defines a linear cutting tip edge 52 extending between adjacent serrations 32. In the illustrated embodiment, each linear cutting tip edge 52 is substantially straight. However, as may be recognized by those of ordinary skill in the pertinent art based on the teachings herein, the cutting tip edges 52 may take any of numerous different shapes and configurations that are currently known or that later become known. For example, each cutting tip edge 52 may be substantially curvilinear or may include at least a portion which is substantially curvilinear and/or a portion which is substantially straight.
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The body 28 of the blade 18 preferably defines a thickness within the range of about 50/1000 of an inch to about 120/1000 of an inch, and in the illustrated embodiment is about 62/1000 of an inch. One advantage of forming the serrations on only one side of the blade is that it avoids forming an overly thin section at the cutting edge 26 that otherwise might give rise to premature chipping or breakage of the blade. Yet another advantage of the currently preferred embodiment is that the non-serrated side of the blade nevertheless defines a plurality of axially-spaced recesses thereon formed by the serrations on the opposite side of the blade, and a plurality of discrete cutting tips formed between the recesses, that contribute to reducing the cutting forces and otherwise facilitating the ability to cut through work pieces. However, as may be recognized by those of ordinary skill in the pertinent art based on the teachings herein, the serrated blades may take any of numerous different configurations, including serrated configurations, that are currently known, or that later become known, including serrations formed on both or opposite sides of the blade, serrations defining different shapes and/or configurations than that shown, and/or different serrations on different sides of the blade or on different portions of the blade.
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In the operation of the serrated pipe cutter 10, the pipe is placed within the hollow recess 58 of the jaw. The user manually engages the grips 56 and 16 and squeezes the handles 12 and 14 together. This action brings the tips of the blade 18 into initial contact with the pipe. The handles 12 and 14 are further squeezed together to drive the blade 18 into the pipe. The serrations 32 ease the frictional force between the pipe and the blade as the blade passes through the pipe. The blade passes through the pipe and at least a portion of the blade is received within the slot 60 in the second position to ensure a clean cut. When the grips 16 and 56 have been squeezed together, and the handles 12 and 14 are subsequently in a closed position, the locking mechanism 62 may be engaged to retain the handles in the closed position, for example, for safety or storage purposes.
As will be recognized by those skilled in the pertinent art based on the teachings herein, numerous changes and modifications may be made to the above-described and other embodiments of the present invention without departing from its scope as defined in the appended claims. For example, the handles, locking mechanism, and blade may be made of any of numerous different materials, or combinations of materials, that are currently known, or that later become known for performing their functions and/or depending on the application. In addition, the features of the serrated pipe cutter disclosed herein, and of the serrated blade, may be employed by other types of cutting tools or implements for cutting articles other than pipes. The handles can take numerous configurations; for example, the handles can be movable relative to one other, other than pivotally, as shown, in any way that is known or becomes known, such as by one or more linkages. The blade serrations and cutting tips can take on any of numerous shapes and/or configurations; for example, the cutting edge can include adjacent serrations without intervening cutting tips and/or adjacent tips without intervening serrations. Likewise, the hollow recess for supporting the article to be cut can take on any of numerous different shapes and/or configurations. Accordingly, this detailed description of preferred embodiments is to be taken in an illustrative, as opposed to a limiting sense.
