Patent Application
20160089812
Example embodiments relate to a saw that is appropriate for cutting control joints in green concrete, and more particularly relate to a saw having a diamond blade with a thicker core and thin cutting portion with a non-contact shoulder forming a portion of the transition between thicknesses.
Concrete is typically formed in a flowing state to enable the concrete to be evenly spread over a surface. The concrete can then be worked and/or finished before hardening. After finishing, the concrete is generally allowed to cure or set to transition into a characteristically hard state.
During curing or setting, the concrete tends to shrink while hardening. In the absence of any crack prevention efforts, the shrinking process would undoubtedly generate cracks at various locations throughout the concrete. These cracks are unsightly, but can also lead to accelerated degradation of the concrete.
To prevent or at least inhibit the generation of cracks in undesirable locations, and to improve the general appearance and quality of the finished product, it is common practice to cut control joints in the concrete so that the cracks that form will occur at controlled locations where the control joints have been cut.
The cutting of control joints is typically performed with a saw assembly having a special blade for cutting green concrete. In the past, the thickness of the blade has typically been between about 2.4 mm to about 3.2 mm. However, more and more large industrial floor projects are specifying thinner control joint widths of, for example, 1.6 mm to about 2 mm. The provision of thin blades for making such cuts has generally compromised the cutting speed and the lifespan of the thin blades used to make such cuts due to the lack of rigidity of the thin core.
Thus, improvements in blade design may be warranted.
To provide a saw blade that is capable of making thin cuts of approximately 2 mm or less for control joints in green concrete at a high speed, some example embodiments may employ a non-contact shoulder to provide a transition between a thicker core and a thinner cutting portion. The thicker core may provide the stability necessary to allow the blade to be operated at relatively high speed, and the non-contact shoulder may provide a transition to the thinner cutting portion so that the desirable thin cut can be achieved. Moreover, the thinner cutting portion may be displaced from the non-contact shoulder by sufficient distance to ensure that the non-contact shoulder does not come into contact with the concrete. To achieve this, a portion of the main body that forms the core may be extended beyond the non-contact shoulder to place the thinner cutting portion far enough from the non-contact shoulder that the desired cutting depth can be achieved without bringing the non-contact shoulder into contact with the concrete.
In accordance with an example embodiment, a saw blade for rotating about an axis to cut concrete is provided. The blade may include a main body and a cutting portion. The main body may include an inner section and an outer section. The inner section may have a first thickness in an axial direction that is greater than a second thickness of the outer section. The cutting portion may include a diamond-metal matrix joined to the outer section to cut a material responsive to rotation of the blade. The inner section may extend radially outwardly from a center of the blade to a non-contact shoulder at the first thickness to transition to the outer section at the second thickness. The outer section may extend radially outwardly to an outer diameter of the main body.
In accordance with another example embodiment, a saw assembly may be provided where the saw assembly employs a blade of an example embodiment.
In the following description of preferred embodiments, reference will be made to the accompanying drawings, in which,
The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which example embodiments of the invention incorporating one or more aspects of the present invention are shown. In the drawings, like numbers refer to like elements.
For a typical 12 inch blade, the thinnest steel core that can typically be purchased is about 1.5 mm. The cutting portion of such a blade may be expected to be formed of one or more cutting segments that are made of a diamond-metal matrix. The cutting portion may be laser welded onto the steel core, and may have a thickness of about 2 mm. Thus, in cross section, the cutting portion may form a T shape relative to the steel core and the cutting portion may engage the aggregate to cut the aggregate responsive to operation of the saw blade.
When the steel core is rotated at high speeds, stability problems may be encountered. Thus, saw blades such as the one described above must be operated at lower speeds when under load. These blades have also experienced shorter usable lifetimes. As mentioned above, some example embodiments may provide operators with the ability to provide thin cuts when cutting control joints as previously described (See
As shown in
To accomplish the transition from the thicker main body portion to the thinner cutting section, example embodiments may employ a non-contact (or contact-less) shoulder portion that is configured to make the thickness transition, but never contact the material or surface being cut.
As shown in
The cutting portion 220 may be formed from a diamond-metal matrix to give the cutting portion 220 an appropriate diamond-metal composition to enable it to cut green concrete. The cutting portion 220 may be joined to the outer section 214 such that the cutting portion 220 extends radially outwardly from the outer section 214 to cut material responsive to rotation of the blade 200. The joint therebetween may be provided by laser welding, spot welding, gluing, soldering or any other suitable method of adhesion. Although not required, the cutting portion 220 may be divided into segments 240 that may be divided from each other by slots 250. The slots 250 may extend radially inwardly from the outer edges of the blade 200 and may be used to carry material out of the groove being cut when the blade 200 is employed.
The slots 250 may have any suitable length. However, for a typical example of the blade 200, which may have a diameter of about 8 inches to about 18 inches, the slot 250 (if employed) may be expected to have a length of between about 1/16 inch to about ¾ inch. Although the cutting portion 220 could also have any suitable length including a length (in the radial direction) that is less than, equal to, or greater than the length of the slot 250, some example embodiments may employ a cutting portion length of about 1 inch to about 2 inches.
As shown in
In an example embodiment, the cutting portion 220 may have a third thickness (T3) that is approximately equal to or less than the first thickness (T1) and greater than the second thickness (T2). As such, the cutting portion 220 may essentially form somewhat of a T-shape relative to the outer section 214 and overhang each lateral side of the outer section 214 slightly. In some cases, the difference between the second thickness (T2) and the third thickness (T3) may be about ½ mm. However, larger or smaller differences could be employed in some other embodiments. Since, as stated above, the blade 200 of an example embodiment may be provided to allow thin cuts of between about 1.5 mm to about 2 mm, it can be appreciated that the third thickness (T3) may also be less than or equal to about 2 mm (e.g., about 1.3 to about 2.2 mm), and the second thickness (T2) may be less than about 1.8 mm. Meanwhile, the first thickness (T1) may be approximately equal to or substantially greater than the third thickness (T3). For example, the first thickness may be about 2 to 5 mm in some embodiments or more broadly can be in a range from about 2 to 20 mm. In some cases, the second thickness (T2) may be below 2.2 mm, below 2 mm, below 1.8 mm or below 1.6 mm.
The non-contact shoulder 260 may be formed by material disposed to extend from a surface of the inner section 212 to a surface of the outer section 214 at an angle. In some embodiments, the transition between the first and second thicknesses (T1 and T2), which is accomplished at the non-contact shoulder 260, may be made by tapering the sides of the blade 200 from the first thickness (T1) to the second thickness (T2). However, in some cases, the transition may be made instantaneously and without tapering. Thus, the angle formed between the outer section 214 and the inner section 212 may be equal to 90 degrees (as shown in
As can be appreciated from
The non-contact shoulder 260 may, as the name suggests, be provided at a distance away from a distal edge (or periphery) of the cutting portion 220 that is greater than the cutting depth so that there is no contact between the non-contact shoulder 260 and the material being cut. Thus, for example, if the cutting depth is about 41 mm, then the non-contact shoulder 260 may be located at least about 45 mm or more from the distal edge of the cutting portion 220. In order to increase stability while still providing the ability to make high speed, thin cuts, the non-contact shoulder 260 may be provided relatively close to the cutting depth, but still provide a buffer to ensure that the non-contact shoulder 260 does not contact the material being cut. Because the non-contact shoulder 260 is not designed to contact the material being cut, the shape of the non-contact shoulder 260 is not a critical design feature and thus, there can be a great deal of flexibility offered relative to the shape to be employed for the non-contact shoulder 260.
As shown in
Based on the descriptions and drawings provided above, it should be appreciated that a saw blade for rotating about an axis to cut green concrete is provided herein. The blade may include a main body and a cutting portion. The main body may include an inner section and an outer section. The inner section may have a first thickness in an axial direction that is greater than a second thickness of the outer section. The cutting portion may include a diamond-metal matrix joined to the outer section to cut a material responsive to rotation of the blade. The inner section may extend radially outwardly from a center of the blade to a non-contact shoulder at the first thickness to transition to the outer section at the second thickness. The outer section may extend radially outwardly to an outer diameter of the main body.
The blade of some embodiments may include additional features that may be optionally added either alone or in combination with each other. For example, in some embodiments, (1) the inner section may be comprised of a steel core having the first thickness (T1) of about 2 mm to about 20 mm. In addition to (1) or as an alternative, in some embodiments, (2) the first thickness (T1) may be up to about ten times larger than the second thickness (T2). In addition to (1) and (2) or as an alternative, in some embodiments, (3) the second thickness (T2) may be less than about 2 mm.
In some embodiments, any or all of (1) to (3) may be employed in addition to the optional modifications or augmentations described below. For example, in some embodiments, the non-contact shoulder may be formed at a 90 degree angle relative to a face of the outer section, although other angles including, for example, 45 degrees, are also possible. Additionally or alternatively, the outer section and the inner section may be integrally formed from a same piece of material. As an alternative, the inner section may include a center hub that extends beyond the non-contact shoulder to form the outer section. The inner section may further include a first plate disposed on a first face of the center hub and a second plate disposed on an opposite face of the center hub. Each of the first and second plates may terminate at the non-contact shoulder. Additionally or alternatively, the cutting portion may have a third thickness (T3), and the third thickness (T3) may be greater than the second thickness (T2) and may be approximately equal to or less than the first thickness (T1). Additionally or alternatively, the non-contact shoulder may be separated from a distal end of the cutting portion by a distance greater than a cutting depth of the saw blade. Additionally or alternatively, the blade may further include slots extending radially inwardly from a periphery of the blade to separate the cutting portion into segments.
Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although the foregoing descriptions and the associated drawings describe exemplary embodiments in the context of certain exemplary combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, different combinations of elements and/or functions than those explicitly described above are also contemplated as may be set forth in some of the appended claims. In cases where advantages, benefits or solutions to problems are described herein, it should be appreciated that such advantages, benefits and/or solutions may be applicable to some example embodiments, but not necessarily all example embodiments. Thus, any advantages, benefits or solutions described herein should not be thought of as being critical, required or essential to all embodiments or to that which is claimed herein. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
