RELATED APPLICATIONS

[0001] This patent application claims priority to and all the benefits of U.S. Provisional Patent Application No. 62/797,985 filed on January 29, 2019, which is herein incorporated by reference in its entirety.

BACKGROUND

[0002] Known reciprocating saw blades include blades having angled rake tips and triangular tips.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] FIG. 1 illustrates an example saw blade with a perspective view thereof.

[0004] FIG. 2 is a top view of the example saw blade of FIG. 1.

[0005] FIG. 3 is a side view of the saw blade of FIG. 1.

[0006] FIG. 4 is an enlarged broken-out view of the portion of the saw blade in circle 4 of FIG.

3.

[0007] FIG. 5 is a front view of the saw blade of FIG. 1.

[0008] FIG. 6 is a broken-out view of the saw blade of FIG. 5 in the direction of arrow 6.

[0009] FIG. 7 is a broken-out view of the saw blade in the direction of arrow 7 of FIG. 3 and

FIG. 5.

[0010] FIG. 8 is an enlarged view of the portion of the saw blade in circle 8 of FIG. 5.

[0011] FIG. 9 is a first alternative example saw blade.

[0012] FIG. 10 is a second alternative example saw blade.

[0013] FIG. 11 is a third alternative example saw blade.

[0014] FIG. 12 is a view of an example blade material sheet.

[0015] FIG. 13A is a side view of an example saw blade blank in an example first condition, as may be formed from the sheet of FIG. 12.

[0016] FIG. 13B is a side view of the example saw blade blank of FIG. 13A in an example intermediate condition.

[0017] FIG. 13C is a top view of the example saw blade blank of FIGs. 13A and 13B in an example completed condition.

[0018] FIG. 14 is a flow chart showing example process steps for forming a saw blade consistent with FIGs. 13 A, 13B and 13C.

DETAILED DESCRIPTION

[0019] The prior art does not address the need to provide smooth cuts that avoided snagging metal foam material during cutting. Scalloped teeth may bend at their tips and snag a work piece, e.g., metal foam, and may result in a rougher cut edge of the work piece.

[0020] A saw blade comprises an elongate body including a plurality of teeth. The body extends along an axis and has a substantially planar distal portion. The teeth are disposed along a first edge of the body substantially parallel to the axis. Tips of the teeth have a blunt surface.

[0021] The body of the saw blade may have a proximal portion fixed to and oppositely disposed relative to the distal portion wherein the distal portion includes the plurality of teeth. The proximal portion may include a retention surface.

[0022] A reciprocating saw blade comprises an elongate body. The body extends along an axis and has a proximal portion fixed to an oppositely disposed and substantially planar distal portion. The proximal portion includes a retention surface. The distal portion includes a plurality of teeth substantially coplanar therewith and disposed along a first edge of the body substantially parallel to the axis. Tips of the teeth have a blunt surface.

[0023] The teeth may be formed by a plurality of scallops on a first side of the body.

[0024] The teeth may be formed by a plurality of radiused scallops on a first side of the body.

[0025] The blunt surfaces may be planar and parallel to the axis.

[0026] The tips of all of the teeth may have a blunt surface.

[0027] A width of the blunt surface may be greater than eight percent of a tooth pitch of the teeth.

[0028] A rake angle of the teeth at the tips may be substantially equal to negative 77.4 degrees.

[0029] A method of forming a saw blade comprises the steps of selecting a blade material, forming a blade blank, and forming a plurality of teeth. The blade blank has a distal portion that is substantially planar and extends along an axis. The teeth are substantially coplanar with the distal portion and are disposed along a first edge of the distal portion. The first edge is substantially parallel to the axis. Blunt surfaces are formed on tips of the teeth. [0030] The teeth may be formed by removing material from the first edge to form a plurality of radiused scallops on a first side of the distal portion.

[0031] The blunt surfaces may be defined by the first edge by orienting the teeth relative to the first edge.

[0032] The blunt surfaces may be formed so that a width of the blunt surfaces is greater than eight percent of a tooth pitch of the teeth.

[0033] The blunt surfaces may be formed so that a rake angle of the teeth at the tips is substantially equal to negative 77.4 degrees.

[0034] Relative orientations and directions (by way of example, distal, proximal, upper, lower, bottom, rearward, front, rear, back, outboard, inboard, inward, outward, lateral, left, right) are set forth in this description not as limitations, but for the convenience of the reader in picturing at least one embodiment of the structures described. Such exemplary orientations may be from the perspective of a user of the saw.

[0035] The elements shown may take many different forms and include multiple and/ or alternate components and facilities. The example components illustrated are not intended to be limiting. Indeed, additional or alternative components and/ or implementations may be used.

Further, the elements shown are not necessarily drawn to scale unless explicidy stated as such.

[0036] As illustrated in FIG. 1 through FIG. 8, the saw blade 20 has an example elongate body 22. The elongate body 22 extends along a longitudinal axis 24. The body has an example distal portion 36 that is substantially planar. The body 22 has a first edge 26 substantially parallel to the axis 24, and a second edge 28 opposed to the first edge 26 that may be substantially parallel to the first edge 26, or tapered relative to the first edge 26, i.e., at an angle thereto. A plurality of teeth 30 are disposed along from the first edge 26 of the body. The tips 32 of the teeth 30 have an example blunt surface 34. The teeth 30 are spaced apart by a tooth pitch P. The blunt surface 34 has a width W. The blunt surfaces 34 of the teeth 30 may be substantially parallel to the axis 24.

[0037] The body 22 may also include an example proximal portion 38 that is fixed to and oppositely disposed relative to the distal portion. The teeth 30 may be disposed along and extend from the distal portion 36. The proximal portion 38 may include an example retention surface 40 for receipt by a handpiece (not shown). The retention surface 40 may be provided by a pair of oppositely disposed retention tabs 42 extending from the proximal portion 38.

[0038] The body 22, e.g. the distal portion 36 of the body 22, may have a first thickness T1 between a first side 44 of the body 22 and an opposed second side 46 of the body 22. The first side 44 and the second side 46 may be parallel to each other, and may each extend between the first edge 26 and the second edge 28. The proximal portion 38 may have a thickness T2 differing from the thickness T1 of the distal portion 36 to accommodate receipt of the proximal portion 38 by the handpiece. Illustrative thickness values for T1 and T2 may be, respectively, .032 inches (0.80 mm), and .025 inches (0.64 mm).

[0039] The teeth 30 may be formed by a plurality of scallops 48. A scallop 48 may both define and connect opposed sides of adjacent teeth 30 as illustrated in FIG. 3 and FIG. 4. The tips 32 of the teeth 30 may be separated by the tooth pitch P, an example value of pitch P being 0.220 inches (5.59 mm). The scallops 48 may be radiused. As best shown in FIG. 5, the scallops may be formed at an example angle oc, e.g. 10 degrees, to the first side 44 with an example radius R being .510 inches (6.61 mm). Each of the scallops 48 may have a center axis 49 parallel to the center axes 49 of the other scallops 48, and the axes 49 being oriented at the angle oc relative to the blade body 22.

[0040] The blunt surface 34 may be varied in size with a size of the teeth 30, the size of the teeth 30 including the pitch P of the teeth. For example, the blunt surface 34 may have a width W greater that predetermined percentage, e.g., 8%, of the pitch P. An example width W may be substantially equal to 9% of the pitch P, such a width being .019 inches (0.48 mm).

[0041] When given the width W, the angle oc, the tooth pitch P, and the radius R, a value for a depth D of the blunt surface, as measured in a direction normal to the second side 46 as illustrated in FIG. 7, may be determined. An example depth D, given the above values of W, P, R and oc, may be .002 inches (.05 mm).

[0042] An example edge rake angle b, defined by an angle between a line tangent to the scallop 48 on the second side 46 at the blunt surface 34, and a line normal to the axis 24 as may be indicated by an intersection of the scallops 48, may be negative 77.4 degrees, consistent with the above values of W, P, R and oc. The angle b affects a distribution of downward blade force versus fore-aft force that best facilitates cutting. A shallower engagement angle mitigates toward a greater downward force being required to achieve a particular fore-aft force, increasing a crushing force applied to the blade and against the material being cut. A steeper angle mitigates toward a lower downward force being required to achieve a particular fore-aft cutting force, but may result in cut surfaces of the material being cut being less smooth than may be achieved with the example angle b. The rake angle b, and its associated parameters, may be varied to suit the material being cut. [0043] The width W may alternatively be selected as a function in-part of a size of cells of foam that the blade 20 is to be used to cut, particularly when the foam is an open-cell foam. The blunt surfaces 34, and thus the tips 32, may be sized to be received by at least some of the foam cells. The width W may also be selected to provide the teeth 30, including the blunted tips 32, with a bending strength compatible with allowing the teeth 30 to overcome a shear strength of cell walls of the metal foam, i.e., allowing the teeth 30 to cut through the cell walls without tip breakage.

[0044] FIG. 9 illustrates a first alternative example saw blade 20’ with an elongate body 22’ having an alternative example retention surface 40’ provided by a retention aperture 42’ instead of retention tabs 42. The teeth may be substantially the same as those described above in the context of FIGs. 1-8.

[0045] FIG. 10 illustrates a second alternative example saw blade 20” with an elongate body 22”. The saw blade 20” has an alternative proximal portion 38” defined by a blade arbor 38”, which in turn has a notch 42” defining an alternative example retention surface 40”. An alternative example distal portion 36” may be fixed to the proximal portion 38” by any appropriate retention technique, e.g., welding, brazing. The use of such a blade arbor 38” is seen in commercially available blades, e.g., Stryker® Reciprocating Saw Precision™ Blades. The teeth may be substantially the same as those described above in the context of FIGs. 1-8.

[0046] FIG. 11 illustrates a third alternative example saw blade 20”’ with an elongate body 22”’ in the form of a band as may be used with a band saw. The saw blade 20”’ is substantially continuous and is provided without a distal portion or proximal portion. The teeth may be substantially the same as those described above in the context of FIGs. 1-8.

[0047] The example blade 20 may be formed in the following manner, consistent with the illustrations of FIG. 12, FIGs. 13A, 13B and 13C and a process illustrated in FIG. 14.

[0048] A material for the blade, i.e., a blade material, is selected, consistent with the example step of process block 60. An example blade material may be a 440 alloy stainless steel. Alternative blade materials may include tungsten carbide blades, and steel blades having tungsten carbide tips forming the teeth 30. Consistent with the example step of process block 62, the material may be provided in any of a ribbon, strip or sheet form. An example sheet 50 of blade material is illustrated in FIG. 12, with phantom lines showing one possible arrangement of blank outlines 52 on the sheet 50. The illustrated example sheet shows fifteen blank outlines 52 in a three by five grid-type arrangement. Other arrangements may be employed, with the number of outlines 52 varying with the size of the outlines 52 and the size of the sheet 50. For example, for blank outlines that may be approximately .6 inches (1.5 cm) by 4 inches (10 cm), and a sheet that may be approximately 12 inches (30.5 cm) by 39 inches (100 cm), the blank outlines may be arranged to allow an example distribution of 153 blank outlines 52 on the sheet 50 with a nine by seventeen grid-type arrangement. The orientation of the blank outlines 52 may be such that the utilization of the sheet 50 to produce blades 20 is maximized. Complete or perfect utilization would be 100%, with no waste of the sheet 50.

[0049] An example sheet thickness may be .032 inches (0.80 mm). Consistent with the example step of process block 64, blade blanks 54 may be cut from the sheet of blade material by a laser in accordance with the blank oudines 52, or may alternatively be formed by stamping, by die cutting, or by any alternative suitable forming method. The retention surface 40, 40’ may be formed as part of the blade body 22, 22’, and may be formed integrally with the forming of the body 22, 22’, consistent with the blades 20 and 20’ of FIGs 1-8 and FIG. 9. Alternatively, the retention surface 40’ may be formed in a separate operation and/ or by a separate tool, e.g., as by piercing the body to form an aperture 42’ defining the retention surface 40’ as shown in FIG. 9. Yet alternatively, the retention surface 40” may be provided by the notch 42” in the blade arbor 38” as shown in FIG. 10 and described above.

[0050] The blanks 54 may, but need not, be entirely cut from the sheet 50 in the cutting operation. The blanks 54 may remain attached in part to the sheet 50 to facilitate continued processing, e.g., localized material removal, as for example by grinding or electrical discharge machining.

[0051] When a thickness T2 of the proximal portion 38 is less than a thickness T1 of the distal portion, the thickness T2 may be achieved by grinding the proximal portion 38 of the blanks 54.

[0052] Consistent with the example step of process block 66, the scallops 48 may be formed, e.g., cut, by wire electrical discharge machining of the scallops 48. The blades blanks 54 may be oriented at the angle oc, i.e., substantially at the angle oc, relative to a cutting wire, and the cutting wire moved along the first edge 26 in the axial direction, while being arcuately displaced about the center axis 49 of each of the scallops 48 to form the scallops 48 with a radius R.

[0053] Consistent with the example step of process block 68, the scallops 48 may be oriented, i.e., the scallop center axes 49 located, relative to the first edge 26 of the blade blank 54, to allow the first edge 26 of the blank 54 to define the blunt surfaces 34. For example, to provide scallops at an angle a of 10 degrees with the first edge 26 of the blade blank 54 providing the blunt surfaces 34, the scallops 48 may be cut to an example radius of .510 inches (12.95 mm) with the scallops 48 evenly spaced along the axis 24. The example parallel center axes 49 may be in a common plane 55 and may be separated by the example pitch P of .220 inches (5.59 mm). An intersection of the plane 55 with a projection of the second side 46 defines a first reference line 56, shown as a point in FIG. 8. The axes 49 are normal to the line 56. A second reference line 57, also shown as a point in FIG. 8, is defined by an intersection of the second side 46 and the first edge 26. The common plane 55 and the second reference line 57 are separated by an example distance C of .500 inches (12.70 mm).

With the axes so positioned relative to the reference line 57, the first edge 26 of the blank 54 will define the blunt surfaces 34. By changing any of the controlling parameters, e.g., angle oc, radius R, pitch P, the distance of the axes 49 from the reference line 57, one may adjust the size of the blunt surface 34. As an alternative to using the first edge 26 to define the blunt surfaces of the scallops, the blunt surfaces 34 may be formed by instead orienting the scallops 48 to achieve pointed tips 32, and subsequently flattening the tips 32 by any selected means, e.g., wire electrical discharge machining, grinding, etc., to define the blunt surfaces 34.

[0054] Consistent with the example step of process block 70, the blade blank 54, now a formed saw blade, 20, may be surface treated, e.g., heat treated, coated. Heat treating, e.g., hardening, may be used to harden the blade 20, and particularly the teeth 30. A coating, e.g., diamond-like carbon (“DLC”) coating, titanium nitride coating, may be applied to the blade to enhance the wear characteristics of the blade and the performance characteristics (e.g., coefficient of friction) of the blade.

[0055] As an alternative to electrical discharge machining, the scallops 48 may be ground into the first side 44 with a grinding tool, e.g., a grinding wheel, rotating about an axis substantially parallel to the angle a. For example, a grinding wheel with a dressed radius equal to R may be moved along the center axis 49 of the scallop 48 to form the scallop 48 so that it has a radius substantially equal to R. The blunt surfaces 34 may be formed by grinding them parallel to the axis 24. The teeth 30 may be formed in blades 20 individually, or a plurality of blades 20 may be appropriately aligned and clamped or otherwise ganged together to allow the simultaneous cutting of teeth 30 in multiple blades 20.

[0056] The blades 20, 20’, 20” may be used with the above-referenced handpiece. The handpiece may include a driving motor, a controller, an operator input control element, e.g., an actuator switch, and a power source, consistent with commercially available handpieces, e.g., the Stryker® RemB® U Driver. The power source may be any one of a battery, a power cord, pneumatic power and hydraulic power.

[0057] In the drawings, the same reference numbers indicate the same elements. Further, some or all of these elements could be changed. For example, the teeth may be triangular in shape with chamfered edges and blunted tips instead of scalloped. With regard to the processes, systems, methods, etc. described herein, it should be understood that, although the steps of such processes, etc. have been described as occurring according to a certain ordered sequence, such processes could be practiced with the described steps performed in an order other than the order described herein. It further should be understood that certain steps could be performed simultaneously, that other steps could be added, or that certain steps described herein could be omitted. In other words, the descriptions of processes herein are provided for the purpose of illustrating certain embodiments, and should in no way be construed so as to limit the claims.

[0058] Accordingly, it is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided would be apparent upon reading the above description. The scope should be determined, not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. It is anticipated and intended that future developments will occur in the technologies discussed herein, and that the disclosed systems and methods will be incorporated into such future embodiments. In sum, it should be understood that the application is capable of modification and variation.

[0059] As used herein, the adverb“substantially” means that a shape, structure, measurement, quantity, time, etc. may deviate from an exact described geometry, distance, measurement, quantity, time, etc., because of imperfections in materials, machining, manufacturing, transmission of data, computational speed, etc.

[0060] All terms used in the claims are intended to be given their ordinary meanings as understood by those knowledgeable in the technologies described herein unless an explicit indication to the contrary is made herein. In particular, use of the singular articles such as“a,”“the,”“said,” etc. should be read to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary.

[0061] The Abstract is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in various embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.