Patent Application
20120042756
This invention relates to stabilization of circular saw blades, and more particularly to the stabilization of large circular saw blades of the type used in cut-off sawing operations for workpieces made of metal.
Over a period of more than three decades, the Assignee of the present invention has demonstrated that its cut-off sawing systems using circular saw blades consistently out perform band saws and other cutting systems for cutting railroad rails, forging, billets and other workpieces made of metal. Specifically, equipment manufactured by the common Assignee of the present invention has utilized saw blades approaching six feet in diameter to cut workpieces of up to 24 inches in height and/or width at speeds 10 times faster than systems utilizing band saws. Use of the Assignee's circular cut-off saw systems has also repeatedly demonstrated an ability to cut more precisely, economically and reliably than other types of cut-off systems.
In order to achieve a high level of precision in cut-off length, and a smooth finish on the cut-off surface of the finished workpiece, using a circular saw blade, it is necessary to deal with a number of factors affecting the path of the saw blade as it enters and passes through the workpiece during the sawing operation. For example, the saw blade needs to be precisely constructed from suitable materials which will minimize dimensional inaccuracies of the blade itself, both at rest and while exposed to the working loads and heat generated during the cut-off process. The blade must also be accurately and securely mounted on a driving spindle in a manner which reduces wobble and run-out of the cutting edge. The configuration of the cutting teeth on the cutting edge of the saw blade can also influence on how true the blade will run and the nature of vibration introduced into the blade during the cutting operation. Such circular saw blades are also inherently distorted by vibration modes induced in the circular disk of the blade by the action of the teeth on the cutting edge impacting on and slicing through the workpiece.
Through the years, the Assignee and others involved in utilizing circular saw blades for cutting wood, metals and other materials have disclosed a variety of apparatuses and methods for dealing with the various factors influencing the performance of a circular saw blade. For example, commonly assigned U.S. Pat. No. 3,656,393 to Goellner discloses a method and apparatus for driving a saw blade and positively locking the saw blade to the nose of a driving spindle in a manner which minimizes backlash between the blade and spindle. Commonly assigned U.S. Pat. No. 4,463,645 to Goellner discloses a circular saw blade having a dual chip-cutting action in which all of the saw teeth are of like width and radial height to improve cutting action of the blade in a variety of respects, including significantly changing the manner in which the cutting teeth impact upon and cut through a workpiece in a way which positively influences deformation of the blade disk as a result of vibration induced by the cutting action of the saw teeth through the workpiece.
Those skilled in the art have long recognized that, for purposes of stabilizing a circular saw blade, it is the first mode of vibration as illustrated in
Through the years, a number of prior approaches have been disclosed for stabilizing a circular saw blade by placing matching pairs of stabilizers on opposite sides of the saw blade. The following US patent documents illustrate a number of prior approaches to stabilizing a circular saw blade, by placing pairs of stabilizer pads or other devices on opposite sides of the saw blade, with those pairs of pads being placed in some disclosures along a desired node line for the saw blade: U.S. Pat. No. 3,483,858 to Jansen; U.S. Pat. No. 4,136,590 to Kordyban; U.S. Pat. No. 4,563,928 to Salomonsson; U.S. Pat. No. 5,213,020 to Pleau; U.S. Pat. No. 7,127,978 to Boss; and US Published Patent Application 2006/0174497 to Belfiglio.
In general, these previous approaches to stabilizing a saw blade are directed toward circular saw blades used in rip-sawing arrangements. In rip-sawing, the conditions acting on the saw blade are different than for a typical cross-cutting arrangement. For example, in a rip-sawing arrangement, the workpiece along a longitudinal axis of the workpiece is typically mounted in some sort of movable carriage arrangement which directs the workpiece over, and pushes the workpiece past the saw blade, with the saw blade being mounted on a stationery cradle or frame arrangement. In cross-cutting arrangements, it is typically preferred to have the workpiece be mounted in a stationery cradle and have the saw blade mounted in a moveable carriage which can be manipulated to direct the saw blade across the longitudinal axis of the workpiece along an axis of motion in a cutting plane.
In a rip-sawing arrangement, providing stabilization for a saw blade is more readily accomplished, because the stabilizers can be mounted in a fixed location with respect to the circular saw blade. For cross-cutting saw operations, having the stabilizing elements in a fixed position with relation to the saw blade, at a location providing effective and efficient blade stabilization, has heretofore presented significant design difficulties, partly caused by having the blade move across the workpiece, as opposed to having the workpiece move across the blade.
What is needed, therefore, is an improved method and apparatus for stabilizing a circular saw blade, and particularly such an improved method and apparatus which is effective in a cross-cutting arrangement.
This invention provides improved stabilization of a circular saw blade through use of a blade stabilizer mounted adjacent a workpiece in a fixed relationship to the workpiece and having a stabilizer contact element adapted to bear against the circular saw blade and exert a force against the saw blade in a direction substantially perpendicular to the cutting plane of the saw blade at a point on at least one of the blade faces on the working side of the blade, proximate an axis of motion passing through an axis of rotation of the saw blade and the workpiece in the cutting plane, as the circular saw blade and/or the workpiece move relative to one another along the axis of motion. Some forms of the invention may also utilize additional blade stabilizers, in accordance with various aspects of the invention. The invention may be used in various forms with sawing arrangements and operations having a linear axis of motion, and also with sawing arrangements and operations having a curved axis of motion.
In one form of the invention, an apparatus for stabilizing a circular saw blade is provided. The circular saw blade has a diameter and is mounted for rotation in a cutting plane which is coplanar to a cutting plane. The saw blade is moveable along an axis of motion of the saw blade extending through the axis of rotation within the cutting plane, for cutting a workpiece extending through the cutting plane along a workpiece axis in such a manner that the workpiece axis extends through the cutting plane. The saw blade also defines oppositely-oriented first and second faces thereof which are joined by a cutting edge extending around a periphery of the circular saw blade. The saw blade further defines a working side thereof extending toward the workpiece axis along the axis of motion of the saw blade, and a non-working side of the saw blade extending oppositely from the workpiece axis along the axis of motion of the circular saw blade. The contact element exerts a force against the saw blade in a direction substantially perpendicular to the cutting plane at a point on at least one side of the blade faces proximate to the axis of motion of the saw blade on the working side of the blade as the axis of rotation of the circular saw blade moves laterally along the axis of motion.
In some forms of the invention, stabilizer contact element is retractable away from the saw blade. Some forms of the invention may also include a control arrangement operatively connected between the stabilizer contact element and the blade, for automatically retracting the stabilizer contact element when the cutting edge enters a predetermined zone of proximity to the stabilizer contact element, to thereby preclude contact between the cutting edge and the stabilizer contact element. A control arrangement, according to the invention, may also perform other functions such as: regulating the force exerted by the stabilizer contact element against the blade. The controller may perform a function including, but not limited to automatically extending and/or retracting the stabilizer contact element, and controlling the force exerted by the stabilizer element as a function of an operating parameter such as a relative position between the blade and the workpiece, a measurement of vibration during a sawing operation, rotational speed of the cutting blade, and/or any other appropriate operating parameter.
Some forms of a first blade stabilizer, according to the invention, include a fluid pressure chamber operatively connected to the stabilizer contact element for urging the stabilizer contact element to move in a direction perpendicular to the saw blade in response to the application of an actuating fluid pressure within the fluid pressure chamber. In some forms of the invention, pressured fluid from the fluid pressure chamber is directed between the stabilizer contact element and the face of the saw blade, when the stabilizer contact element is proximate to the face of the saw blade.
A first blade stabilizer, according to the invention may also include a return spring for urging movement of the stabilizer contact element to a non-actuated position when actuating fluid pressure is not present in the fluid pressure chamber. In forms of the invention having pressurized fluid from the fluid pressure chamber directed between the stabilizer contact element and the face of the saw blade, the stabilizer apparatus may further include a flow restrictor to limit flow of the pressurized fluid directed between the stabilizer contact element and the face of the saw blade.
Some forms of the invention may also include a secondary blade stabilizer mounted opposite the first blade stabilizer substantially along the axis of motion of the saw blade in a fixed relationship to the rotational axis of the saw blade. Such a secondary blade stabilizer may have one or more stabilizer contact elements adapted to bear against the circular saw blade and exert a force against the saw blade in a direction substantially perpendicular to the cutting plane at a point on at least one of the blade faces proximate to the axis of motion of the saw blade on the non-working side of the blade, as the axis of rotation of the saw's blade moves along the axis of motion of the saw blade. The secondary stabilizer contact elements may be retractable away from the saw blade to allow for passage of the cutting edge, in some forms of the invention.
A secondary stabilizer, according to the invention, may include first and second secondary stabilizer contact elements operatively mounted for bearing against first and second faces of the circular saw blade. The first and second secondary stabilizer contact elements may be independently adjustable in a direction substantially perpendicular to the cutting plane, for bringing the first and second secondary stabilizer elements into a bearing relationship against the first and second faces of the circular saw blade respectively.
In some forms of the invention, at least one secondary stabilizer contact element may be eccentrically mounted on a rotatable secondary stabilizer mounting shaft which defines an axis thereof. The secondary stabilizer contact elements are eccentrically mounted in such a manner that rotation of the mounting shaft about its axis urges the secondary stabilizer contact element mounted to that shaft toward the saw blade.
In some forms of the invention, a secondary stabilizer contact element may be a stabilizer roller mounted for rotation about a stabilizer roller axis that is offset from and extends substantially parallel to the secondary stabilizer mounting shaft axis, with the stabilizer roller also having an outer surface thereof adapted for contact with the face of the saw blade.
In some forms of the invention, wherein the circular saw blade is moveable along the axis of motion between a maximum retracted position and a maximum extended position of the circular saw blade with respect to the workpiece axis, the secondary stabilizer contact elements are positioned between the cutting edge and the axis of the circular saw blade regardless of the position of the circular saw blade along the axis of motion.
In some forms of the invention, at least one secondary stabilizer contact element is a stabilizer shoe mounted for pivotable movement about a secondary stabilizer shoe axis that is offset from and extends substantially parallel to the secondary stabilizer mounting shaft axis. The secondary stabilizer shoe may have an outer surface thereof adapted for contact with the face of the saw blade. Such a secondary stabilizer shoe may also be moveable linearly along the axis of the secondary stabilizer mounting shaft, in some forms of the invention. The secondary stabilizer shoe may be mounted for rotation about a stabilizer shoe axis that is offset from and extends substantially parallel to the axis of a secondary stabilizer mounting shaft, so that the contact face of the stabilizer shoe is rotatable about the offset axis. A stabilizer shoe, according to the invention, may also include a friction element, which may take the form of a deformable O-ring, for example, disposed for resisting rotation of the stabilizer shoe to thereby facilitate positioning of the contact face of the stabilizer shoe in relation to the face of the saw blade.
A method for stabilizing a circular saw blade, in accordance with the invention, may include exerting a stabilizing force against the saw blade in a direction substantially perpendicular to the cutting plane at a point on one of the blade faces proximate the axis of motion of the saw blade on the working side of the blade as the axis of rotation of the circular saw blade moves laterally along the axis of motion.
A method, according to the invention, may also include adjusting the stabilizing force exerted against the face of the saw blade to achieve a desired stability condition. A stabilizing force may be exerted against the face of the saw blade with a blade stabilizer mounted adjacent the workpiece axis in a fixed relationship to the workpiece axis and having a stabilizer contact element adapted to bear against the circular saw blade. The stabilizer contact element may be retracted away from the saw blade to allow for passage of the cutting edge.
A method, according to the invention, may include exerting a secondary stabilizing force against the saw blade in a direction substantially perpendicular to the cutting plane at a point on at least one of the blade faces proximate to the axis of motion of the saw blade on the non-working side of the blade, as the axis of rotation of the circular saw blade moves along the axis of motion. The secondary stabilizing force exerted against the saw blade may be adjusted to achieve a desired stability condition. The secondary stabilizer contact force may be directed against the face of the blade at a fixed location with respect to the saw blade rotational axis as the circular saw blade rotational axis moves along the axis of motion. The fixed location for applying the secondary forces may be adjusted to achieve a desired stability condition.
In some forms of the invention, secondary stabilizing forces may be oppositely directed on both blade faces proximate the axis of motion of the saw blade on the non-working side of the blade as the axis of rotation of the circular saw blade moves along the axis of motion. The oppositely-directed secondary stabilizing forces may be substantially coaxial with one another.
The invention may also include exerting a stabilizing force against saw blade in a direction substantially perpendicular to the cutting plane at a point on one of the blade faces proximate the axis of motion of the saw blade on the working side of the blade as the axis of rotation of the circular saw blade moves laterally along the axis of rotation.
In some forms of the invention, the workpiece and stabilizer are fixed in relative position to one another, and the axis of rotation of the circular saw blade moves along the axis of motion through a cutting plane intersecting the workpiece. In other embodiments of the invention, the axis of rotation of the circular saw blade is fixed, and the workpiece and first blade stabilizer are fixed in relationship to one another, but moveable along the axis of motion to thereby move the workpiece axis through the circular saw blade while the circular saw blade is rotating within the cutting plane.
The invention may also take the form of a sawing apparatus for cutting a workpiece along a cutting plane using a circular saw blade stabilized by a stabilizer according to the invention. Such an apparatus may include a circular saw blade arrangement and a workpiece support arrangement operatively connected for movement relative to one another along an axis of motion within the cutting plane.
A circular saw blade arrangement, according to the invention, may include the circular saw blade mounted for rotation in the cutting plane about an axis of rotation. The circular saw blade defines oppositely oriented first and second faces thereof joined by a cutting edge extending around the periphery of the circular saw blade. The saw blade further defines a working side of the circular saw blade for cutting through the workpiece and a non-working side of the circular saw blade extending oppositely from the working side of the circular saw blade.
A workpiece support arrangement, according to the invention, may be operatively configured for supporting a workpiece therein with the workpiece oriented to extend through the cutting plane. The workpiece support arrangement includes a blade stabilizer having a stabilizer contact element adapted to bear against the circular saw blade and exert a force against at least one of the faces of the circular saw blade. The stabilizer contact element is further adapted when positioned such that the force exerted by the stabilizer contact element is directed substantially perpendicular to the cutting plane at a point of contact proximate the axis of motion on the working side of the blade, as the circular saw blade arrangement and workpiece support arrangement move relative to one another along the axis of motion.
The invention may also take the form of a blade stabilizer apparatus, according to the invention, for cutting a workpiece along a cutting plane with a circular saw blade, when the workpiece is supported in a workpiece support arrangement and the circular saw blade is mounted in a circular saw blade arrangement. The circular saw blade is mounted for rotation in the cutting plane about an axis of rotation. The circular saw blade defines oppositely oriented first and second faces thereof joined by a cutting edge extending around the periphery of the circular saw blade. The saw blade further defines a working side of the circular saw blade for cutting through the workpiece and a non-working side of the circular saw blade extending oppositely from the working side of the circular saw blade. The circular saw blade arrangement and workpiece support arrangement are operatively connected for movement relative to one another along an axis of motion within the cutting plane. The blade stabilizer apparatus may include a stabilizer body and a stabilizer contact element. The stabilizer body is configured for affixed attachment to the workpiece support arrangement. The stabilizer contact element is operatively attached to the stabilizer body and adapted to bear against the circular saw blade and exert a force against at least one of the faces of the circular saw blade in a direction substantially perpendicular to the cutting plane, at a point of contact proximate to the axis of motion on the working side of the blade, as the circular saw blade arrangement and workpiece support arrangement move relative to one another along the axis of motion.
In some forms of the invention, a first blade stabilizer is mounted adjacent the workpiece axis in a fixed relationship to the workpiece axis, and has a stabilizer contact element adapted to bear against the circular saw blade.
Other aspects, objects and advantages of the invention will be apparent from the following detailed description and accompanying drawings of exemplary embodiments.
The drawings in conjunction with the written text herein describe exemplary embodiments and various aspects of the present invention. In the drawings:
a and 11b are enlarged views similar to
While the invention is described herein in connection with certain preferred embodiments, there is no intent to limit the scope of the invention to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention.
As shown in
The circular saw blade arrangement 108 includes the circular saw blade 106 mounted for rotation in the cutting plane 104 about an axis of rotation 114 of the circular saw blade 106. As shown in
As shown in
As further illustrated in
As illustrated in
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As indicated in
As shown in
In various embodiments of the invention, it is contemplated that a first blade stabilizer may taken any appropriate form. In the embodiments shown in
As shown in
As also shown in
In practicing the invention, it is contemplated that the first blade stabilizer, operatively connected in a fixed relationship to the workpiece 104 in the manner described above, will provide improved stabilization to the saw blade 106 regardless of the exact location of the point of contact 130 of the stabilizer contact element 128 with one or the other sides 116, 118 of the saw blade 106. Experience has shown, however, that for providing optimal stabilization of the saw blade 106 in some embodiments of the invention, it is desirable to have the point of contact 130 be positioned proximate to the axis of motion 112 along a diametral line 148 extending through the axis of rotation 114 of the saw blade 106 and a point of initial contact 147 on the periphery of the saw blade 106 of the cutting edge 120 of the saw blade 106 with the workpiece 102. With such an arrangement, the force exerted by the contact element 128 at the point of contact 130 tends to cause the single node B, as illustrated in
As a practical matter, however, it may not be possible, or desirable, in some embodiments of the invention to have the stabilizer contact element 128 of the first blade stabilizer 126 contact the saw blade 106 directly along either the line of motion 112 or the diametral line 148 extending through the axis of rotation 114 of the saw blade 106 and the point of initial contact 147 between this cutting edge 120 and the outer surface of the workpiece 102. Such difficulties may be encountered, for example, when the workpiece 102 has an odd shaped, or non-uniform outer surface. It may also be desirable in some applications of the invention to have the contact element 128 displaced somewhat from the axis of motion 112 and/or the diametral line 148 to accommodate movement of other structural elements or features of a sawing apparatus, such as a hub 150 securing the saw blade 106 for rotation about the axis of rotation 114 of the saw blade 106. By displacing the contact element 128 somewhat from the line of motion 112, for example, the saw blade 106 may be able to make a deeper cut in the workpiece 102 without interference between the hub 150 and the contact element 128, in some embodiments of the invention.
Generally speaking, as indicated
As shown in
Although it is contemplated that in many embodiments of the invention only a single first blade stabilizer 126 may be utilized with efficacy for blade stabilization, it is also contemplated that in some embodiments of the invention, as shown in
Where two or more first blade stabilizers, according to the invention, are utilized it is further contemplated that in some embodiments of the invention the multiple first blade stabilizers may be operatively mounted for bearing against the first and second faces 116, 118 respectively of the saw blade 106. In some embodiments, such multiple first stabilizer contact elements may be positioned for contacting the first and second faces 116, 118 along a common axis of force extending substantially perpendicular to the faces 116, 118 of the saw blade 106.
Such multiple first blade stabilizers 126 may also be operatively positioned and controlled either independently, or in a cooperative manner in some embodiments of the invention, to allow for adjustment of the forces exerted against the faces 116 and/or 118 of the saw blade 106. A control arrangement 132 may operatively interconnect such multiple first blade stabilizers in a manner allowing for active adjustment of the force being exerted by the stabilizer elements, or for other actions such as extending and retracting the stabilizer contact elements as a function of some parameter of operation of the sawing arrangement, such as the proximity of the cutting edge 120 to the first blade stabilizer contact element. The position and force exerted by the various stabilizer contact elements 128 may also be controlled as a function of any appropriate operating parameter, such as: a measured displacement or vibration of the saw blade 106, the position of the axis of rotation 114 of the saw blade 106; the diameter, shape or thickness of the workpiece 102; etc.
As shown in
As will be understood from the discussion below, the rollers 154, 156 of the secondary blade stabilizer arrangement 152 are configured to be selectively disposed with regard to the saw blade 106 in such a manner that the rollers 154, 156 exert a force against the saw blade 106 in a direction substantially perpendicular to the cutting plane at a point on the blade faces 116, 118 proximate the axis of motion 112 of the saw blade 106 on the non-working side 124 of the blade 106 as the axis of rotation 114 of the circular saw blade 106 moves along the axis of motion 112 of the saw blade 106. Stated another way, whereas the relative position between the contact element 128 of the first blade stabilizer 126 varies with respect to the axis of rotation 114 of the saw blade 106 as the workpiece 102 and the axis of rotation 114 move relative to one another during the cutting process, the points of contact between the secondary stabilizer contact elements 154, 156 remain constant with respect to the axis of rotation 114 of the saw blade 106 during the cutting operation.
As shown in
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In the exemplary embodiment of the secondary blade stabilizer arrangement 152 of the first exemplary embodiment of the sawing apparatus 100, the secondary stabilizer mount 160 takes the form of a split block arrangement having first and second clamping elements 172, 174 joined by threaded fasteners 176 in such a manner that, with the fasteners 176 loosened as shown in
Those having skill in the art will recognize that a secondary stabilizer according to the invention may take a variety of forms other than those described above with reference to
In order to facilitate manipulation and positioning of the stabilizer shoes 178 in the alternate embodiment of the secondary blade stabilizer arrangement 152, the alternate embodiment of the secondary blade stabilizer arrangement 152A includes a rotation resisting element in the form of an O-ring 184 disposed in an annular groove 186 within the bore 180 of the stabilizer shoe 178. As shown in the sectional portions on the right side of both
As shown in
The workpiece support arrangement 210 of the second exemplary embodiment of the sawing apparatus 200 includes a first blade stabilizer 226 fixedly mounted to the workpiece support arrangement 210 in a fixed relationship to the workpiece 202, during operation of the sawing apparatus 200. The first blade stabilizer arrangement 226 includes a first blade stabilizer contact element 228 which operates in the same manner described in more detail hereinabove with regard to the contact element 128 of the first blade stabilizer 126 of the first exemplary embodiment of the sawing apparatus 200, such that the contact element 228 of the first blade stabilizer 226 may be selectively brought into varying contact with one of the faces of the saw blade 206 of the second exemplary embodiment of the sawing apparatus 200.
As also shown in
In general, it will be appreciated by those having skill in the art that, the secondary exemplary embodiment of the sawing apparatus 200 operates substantially in the same manner as the first exemplary embodiment of the sawing apparatus 100 as relative motion between the circular saw blade arrangement 208 and workpiece support arrangement 210 are affected through pivoting motion of the circular saw blade arrangement 208 about the pivot point 209 from a maximum retracted position of the circular saw blade arrangement 208 shown in dashed lines in
In practicing the invention, it is contemplated that stabilization of the circular saw blade is effective with a wide variety of traditional and non-traditional cutting surfaces of the saw blade. Experience has shown, however, that the stabilizing apparatuses and methods of various embodiments, according to the invention, are particularly effective when used in combination with a circular saw blade having a dual chip cutting action, in accordance with commonly assigned U.S. Pat. No. 4,463,645 to Goellner, the disclosure and teachings of which are incorporated herein in their entirety by reference. A blade 300, according to the U.S. Pat. No. 4,463,645 patent is illustrated in
All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventor expects skilled artisans to employ such variations as appropriate, and the inventor intends for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.
