WO2017180493A1

WO2017180493A1 - Reciprocating saw blade with recessed chip catchments located between the blade teeth

Info

Publication number: WO2017180493A1
Application number: PCT/US2017/026753
Authority: WO
Inventors: Colin FENNESSY
Original assignee: Stryker European Holdings I, Llc
Priority date: 2016-04-15
Filing date: 2017-04-10
Publication date: 2017-10-19

Abstract

A reciprocating saw blade (60) with plural teeth (80) that extend away from the longitudinal axis of the blade. At least one tooth is formed to have a base (82) located adjacent the body (62) of the tooth and a head that extends outwardly from the base. The head defines an outer section of the rake surface (84) the cutting edge (86) and the clearance surface of the tooth. A step surface (90) extends distally forward from an inner end of the rake surface. Consequently between the cutting edges of the teeth there is a receiving void (104) and a chip catchment (108). An opening (106) from the receiving void to the chip catchment is smaller in width than the maximum width of the chip catchment.

Description

RECI PROCATING SAW BLADE WI TH RECE SSED CHI P CATCHMENTS

LOCATED BE TWEEN THE BLADE TEE TH

FIELD OF THE INVENTION

[0001] This invention relates generally to a reciprocating saw blade. More particularly, the saw blade of this invention is formed to have chip catchments between the individual teeth of the blade.

BACKGROUND OF THE INVENTION

[0002] In a surgical procedure it is sometimes necessary to use a saw to remove tissue, including bone and cartilage.

Often a powered saw is used to perform this procedure.

Attached to the saw is a saw blade. A drive assembly internal to the saw oscillates the blade in a back and forth motion. Some saw and blades are designed so that, when the saw is actuated, the blade moves back and forth along their

longitudinal axes. This type of blade is known as a

reciprocating saw blade. This type of blade is provided with teeth that extend outwardly from a bottom surface of the blade body .

[0003] There are some surgical procedures in which it is desirable to use a thin reciprocating saw blade to remove a section of tissue. One such procedure in which this type of blade is used is the procedure in which an artificial ankle is implanted in a patient. In this type of procedure, the reciprocating saw blade is used to remove the bone forming the patient's original ankle so the implant can be fitted in place. Prior to the removal of the bone, a resection guide is fitted to the patient. The resection guide includes a set of slots. The slots precisely define the planes along which the bones forming the ankle should be cut. Once the guide is fitted to the patient, the blade is inserted in the slot and actuated. The bone is cut along the planes defined by the slots. The forming of these cuts along these planes ensures that the implant will properly fit in the space previously occupied by the excised bone.

[0004] Given the small sizes of the bones around the foot, the resection guide used to facilitate the proper placement of an artificial ankle has narrow slots. This ensures the precise shaping of the implant-receiving voids. Typically these slots have a width of 3 mm or less. A saw blade

designed to fit in this size slot must therefore have a width that is only marginally less than the width across the slot.

[0001] An inevitable result of the cutting of bone is that the cut bone forms debris in the vicinity of the cut-forming teeth of the blade. As debris accumulate in front of the teeth, they reduce the cutting efficiency of the blade. This slows the cutting process and the overall time it takes to perform the procedure. This runs contrary to one of the goals of modern surgical practice. Specifically, it is goal to perform a procedure as quickly as possible. Performing a procedure quickly as possible lessens the exposure of the patient to anesthesia. Performing a procedure quickly also minimizes the time the patient's normally covered internal to tissue is exposed to ambient environment and the infection- induce agents inherently in this environment.

[0005] Accordingly, one reciprocating blade is shaped so the teeth of the blade are formed with tapered surfaces.

These tapered surfaces define flow paths through which the debris formed in the cutting process can flow away teeth as these debris are formed.

[0006] The above types of blade provide a means to flow debris away from the cutting edges of the teeth integral with the blade. However, plural numerous steps are believed to be required to manufacture the blade. Specifically, a first process is employed to initially shape the blade. As part of this process, the teeth are shaped to define their outer perimeters. One means to so shape the blade is to laser cut the blade from a blank stock. Once the blade is initially shaped, a second process is required to form the taper in the teeth. Typically, this taper is formed by individually grinding the teeth of the blade. Having to perform the grinding processes on the plural teeth of a reciprocating saw blade can appreciably add to the overall cost of providing the blade .

SUMMARY OF THE INVENTION

[0007] This invention is directed to a new and useful reciprocating saw blade. The saw blade of this invention has features that reduce the accumulation of debris adjacent the cutting edges of the blade teeth. The saw blade of this invention is further designed to facilitate the economic manufacture of the blade.

[0008] The saw blade of this invention is formed so that at least one, if not many of the teeth that extend outwardly from the longitudinal axis of the blade body has a base and a head. The most outer portion of the base of the tooth has a smaller side-to-side width than the adjacent inner portion of the head of the tooth. Consequently between a pair of adjacent teeth there is a void that is not fully open to the gap between the teeth. This void functions as a catchment for holding the debris created by the proximal tooth of the two adjacent teeth .

[0009] In some versions of this invention, this void is defined by a step surface that forms the inner most surface of the head of the tooth. In some specific versions of this invention, this step surface is planner. In more specific versions of this invention, the step surface extends along a line that is parallel to the proximal-to-distal longitudinal axis along the body of the saw blade.

[00010] It is a further feature of some versions of this invention that the rake surface of a tooth forms a uniform distally directed surface of the tooth. The inner portion of the rake surface forms the distally directed surface of the base of the teeth. The outer portion of the rake surface forms the distally directed surface of the head of the tooth.

[00011] A further feature of this invention is that the distally and proximally directed surfaces of the tooth of this blade are substantially, if not completely perpendicular, to the opposed sides of the blade. This makes it possible to in a single shaping process, such as laser cutting, form the blade out a section of stock.

BRIEF DESCRIPTION OF THE DRAWINGS

[00012] The invention is pointed out with particularity in the claims. The above and further features and benefits of this invention are understood from the accompanying Detailed Description taken in conjunction with the accompanying

drawings in which:

[00013] Figure 1 is a side view of a saw to which a saw blade of this invention is attached;

[00014] Figure 2 is an enlarged plan view of the saw blade.

[00015] Figure 3 is a perspective view of the saw blade in which the rake surfaces of bottom directed teeth are visible;

[00016] Figure 4 is a perspective view of the saw blade wherein the clearance surfaces and proximally directed

surfaces of bases of bottom directed teeth are visible;

[00017] Figure 5A is an enlarged plan view of the bottom directed teeth and Figure 5B is a cross section view of the teeth taken along line 5B-5B of Figure 5A; [00018] Figure 6A is an enlarged plan view of the bottom directed teeth and Figure 6B is a cross section view of the teeth taken along line 6B-6B of Figure 6A;

[00019] Figure 7A is an enlarged plan view of the bottom directed teeth and Figure 7B is a cross section view of the teeth taken along line 7B-7B of Figure 7A.

[00020] Figure 8A and 8B depict how, when the blade of this invention is used to cut bone, debris generated by the cutting process accumulate in the catch between adjacent teeth; and

[00021] Figures 9 is a cross sectional view of how, owing to the geometry of the blade, a laser may be used to cut this blade out of stock; and

[00022] Figure 10 is a plan view of the cutting process of Figure 9.

DETAILED DESCRIPTION

[00023] Figure 1 depicts surgical sagittal saw 30 to which a blade 60 of this invention is mounted. The saw 30 includes a pistol shaped body 32. Saw body 32 thus includes a

handgrip 34. A barrel 36, also part of the body 32, extends proximally from the top of the handgrip 34. (Here,

"proximally" is understood to mean towards the surgeon holding the saw 30, away from the site to which the saw blade 60 is applied. "Distally" is understood to mean away from the surgeon holding the saw 30 and towards the site to which the saw blade 60 is applied.) A head 40 extends forward from the distal end of the barrel 36. A blade mount 42 extends forward from the head 40. Blade mount 42 includes components for releasably holding the blade 60 to the head 40. The structure of the components integral with the saw that releasably hold the blade 60 to the saw 30 is not part of this invention.

[00024] A motor 46, represented by a dashed rectangle, is housed in the barrel 36. A transmission 48, represented by a second dashed rectangle, transfers the rotational movement of the motor rotor to a motion that reciprocates the blade mount 42 back and forth. The blade 60, being attached to the blade mount 42, engages in a like motion. More particularly, the blade 60 reciprocates back and forth along the proximal- to-distal longitudinal axis that extends through the blade. The structure of the motor 46 and transmission 48 are not part of the present invention.

[00025] The depicted saw 30 is understood to have a DC motor 46. A battery, not illustrated, is attached to the butt end of the handgrip 34. The battery supplies the current for the energization signals to the motor 46. A manually actuated trigger 50 projects distally forward from the portion of the handgrip below the head 40. Internal to the handgrip 34 is a control module, not illustrated and not part of the present invention. The control module includes at least one sensor that monitors the actuation of the trigger 50. Based on the extent to which the trigger 50 is depressed, the control module selectively controls the application of the

energization signals to the motor. The control module

regulates the application of the application single to cause the motor to run at a speed that results in the desired back and forth reciprocating motion of the blade 60. One such control module that can be incorporated in the saw 32 is disclosed in PCT Pub. No. WO 2007/002180 A2/ US Pat. Pub. No. US 2007/0085496 Al , the contents of which are incorporated herein by reference.

[00026] A saw blade 60 of this invention, as best seen in Figures 2-4, includes an elongated, generally rectangularly shaped body 62. The blade 60 is a single piece structure formed out of a material such as stainless steel. One such stainless steel is 7C27Mo2 martensitic stainless steel. The body 62 has two side surfaces 70, one of which is seen in each of Figure 2, 3 and 4. Opposed top and bottom surfaces, 68 and 72, respectively, extend from the opposed side surfaces 70. In Figure 2 only the edges of the top and bottom surfaces 68 and 72, respectively are seen. In versions of the invention wherein the blade 60 is intended for small bone surgery, the thickness between the opposed side surfaces 70 of the blade is often 3 mm or less and can be 1 mm or less. A blade 60 will have this thickness to ensure that the blade can slip fit in the slots of resection guide used for small bone surgery.

[00027] Tabs 74 extend outwardly from the opposed top surface 68 and bottom surface 72. The tabs 74 are

diametrically opposed to each other relative to the

longitudinal axis through the blade body 62 and are located approximately 14 mm forward of the proximal end of the body. The tabs 74 are dimensioned to seat in complementary slots formed in the blade mount 42. Tabs 74 are the features of the saw blade 60 that facilitate the releasable coupling of the blade to the saw 30.

[00028] The saw blade 60 is further formed to have a head 76 that extends distally forward from the end of the body 62. The opposed top and bottom surfaces of the head taper inwardly from, respectively, the top surface 68 and bottom surface 72 of the body 62. Supplemental teeth 78 project outwardly from the top and bottom surfaces of the head 76.

[00029] Saw blade 60 is further formed so as to have primary teeth, teeth 80, that project outwardly from the bottom surface 72 of the blade body 62. The primary teeth 80 extend outwardly from the section of the body 62 adjacent the head 76 and extend proximal along the body 62 from head 76. Primary teeth 80 typically extend outwardly from the blade body 62 from a section of the body that is often 90% or less and, more typically, 25% to 50% of the overall length of the blade body 62. [00030] Each primary tooth 80 includes a base 82 and a head 98, one of each identified in Figure 6A. A rake

surface 84, one of which is identified in each of Figures 3, 5B, 6B and 7B, is the distally directed surface of a primary tooth 80. Each rake surface 84 extends outwardly, away from the longitudinal axis of the blade body 62 and slightly distally forward. Each rake surface 84 functions as the distally directed surface of both the base 82 and head 98 of the primary tooth with which the rake surface 84 is integral. A clearance surface 88, one identified in each of Figures 4, 6A and 7B, extends proximally rearward and inward from the outer end of each rake surface 84. The edge where the rake surface 84 and clearance surface 88 of each primary tooth 80 meet is the cutting edge 86 of the tooth, two cutting edges identified in Figure 3. Each clearance surface 88 is the proximally directed surface of the head 98 of the primary tooth 80 which the clearance surface is integral.

[00031] A primary tooth 80 of the blade 60 of this invention is further formed so that the clearance surface 88 does not extend the full length of the tooth. Instead, the clearance surface extends a length that extends between 20% and 90% along the line that extends from where the tooth 80 emerges from the blade body 62 to the cutting edge 86. More often, the clearance surface 88 extends a distal that occupies 40% to 60% of the overall length along this line. The primary tooth 80 is formed so a step surface 90 extends distally forward from the inner end of the clearance surface 88. In Figure 6A, the edges of a clearance surface 88 and the associated step surface 90 are identified. Two step

surfaces 90 are identified in Figure 6B . In the illustrated versions of the invention, the step surfaces 90 of primary teeth 80 are in a common plane and this plane is parallel to the longitudinal axis through the blade body 62. Each step surface 90 thus forms the inner face, the inner perimeter of the head 98 of the primary tooth 80 with which the surface 90 is integral.

[00032] A trailing surface 92 extends inwardly from the distal end of each step surface 90. More specifically, as called out in Figures 5B, 7A and 7B, each trailing surface 92 extends inwardly, the trailing surface extends proximally. With the exception of the trailing surface integral with the most proximal of the primary teeth 80, each trailing

surface 92 extends proximally towards where the rake

surface 84 of the proximally adjacent tooth 80 emerges from the body 62 of the blade 60. Each trailing surface 92 is the proximally directed face of the base 82 of the primary

tooth 80 with which the surface 92 is integral.

[00033] It should thus be appreciated that a blade of this invention is thus constructed so that proximal-to-distal width of the outer portion of the base 82 of each primary tooth 80 is less than the proximal-to-distal width of the adjacent inner portion of the head 98 of the tooth 80.

[00034] As identified in Figure 5A, between each pair of adjacent primary teeth 80 there are two voids. Inwardly from cutting edges 86 of the teeth there is an outer void referred to as the receiving void 104. The outer section of the rake surface 84 of the proximal tooth 80 and the opposed clearance surface 88 of the adjacent distal tooth 80 form the side boundaries of the receiving void 104. The plane between the cutting edges 86 of the two teeth form the outer opening, represented by dashed line 102 into the receiving void. A plane that extends proximally from the proximal end of the step surface 90 of the distal tooth to the rakes surface 84 of the proximal tooth forms the inner base of the receiving void 104. In Figure 5A, the base of the receiving void 104 is represented by a dashed line 106. [00035] The base of the receiving void 104 is the opening into the second void, the inner void, identified as the catchment 108. The trailing surface 92 of the distal of the two teeth 80 and the opposed inner portion of the rake

surface 84 of the proximal tooth form the side perimeters of the catchment 108. Since, extending inwardly towards the longitudinal axis through the blade body 62, the rake

surface 84 and trailing surface 92 of the adjacent teeth taper towards each other, catchment 108 has a shape that can

generally be described as triangular. Owing to the presence of the step 90 it should be understood that the base of the receiving void, the opening into the catchment 108 is shorter in proximal-to-distal length than the proximal to distal length of the opening 102 between the cutting edges 86 of the adjacent teeth 80.

[00036] A blade 60 of this invention is readied for use by the attachment of the blade to the saw 30.

[00037] The blade 60 is used the same way a conventional blade is used. The blade 60 is directed against the bone to be cut by positioning the primary teeth 80 against the bone. When the practitioner is ready to cut the bone, he/she

depresses the trigger 50. In response to the detection that the trigger is depressed, the control module causes

energization signals to be applied to the motor 46. The actuation of the motor 46 results in the reciprocation of the saw blade 60.

[00038] As blade 60 reciprocates, moves back and forth along the longitudinal axis of the blade body 62, the practitioner positions the blade so primary teeth 80 press against the bone to be cut. During the distally phase, the forward movement phase, of the blade 60 in a single reciprocation cycle, the movement of the blade in combination with the blade being pushed against the bone causes the rake surfaces 84 of the teeth 80 to shear against the bone 120 as seen in Figures 8A and 8B. This results in the generation of bone dust,

debris 122, immediately above the cutting edge 86, in front of the rake surface 84. The debris pass through the outer opening 102 between the teeth and enter the receiving

void 104.

[00039] As the debris continue to be generated, the later generated debris push the earlier generated debris inwardly. The debris move inwardly in front of the rake surface 84.

The debris move inwardly into the catchment 108. As

represented by curved arrow 124, the debris then move distally forward, in front of the trailing surface 92 of the tooth 80 immediately distally forward of the tooth that formed the debris. The debris move into the space immediately inward of step surface 90 and adjacent the trailing surface 92 of this distally adjacent tooth 80. As seen in Figure 8B, the debris form a clump 128 in this space.

[00040] The clumping of the debris 122 in the chip

catchment 108 reduces the extent to which the debris generated by the cutting process are pushed into the path of the teeth when the blade is engaged in the cutting of bone. This reduction in the accumulation of debris adjacent the cutting edges and the rake surfaces of primary teeth 80 results in a like reduction in which these debris reduce the efficiency of the cutting process. This increases the amount of bone per unit time the bone is cut, (the cutting rate of the saw 32 and blade 60) . This increased efficiency also reduces power required to perform the cut.

[00041] Further when the debris clump initially forms, the clump forms in a space that is spaced away from the rake surface 84. Thus, as the clump initially forms, the clump does not impeded the flow of debris inwardly along the rake surface 94. This minimizes of the blocking of debris flow along the rake surface. This reduced blocking of this debris flow reduces the extent to which the inevitable presence of the debris reduces the efficiency of the cutting process.

[00042] Thus, this invention, while providing a

catchment 108 between the teeth 80 for debris, does so without resulting in the debris initially clumping where the presence of the clump can be detrimental to debris flow, along the rake surface 84.

[00043] A further feature of blade 60 of this invention, is that the top surface 68, the bottom surface 72, the surfaces that define the perimeters of both the supplemental teeth 78 and the primary teeth 80 can all be perpendicular to the opposed side surfaces 70 of the blade. This means that, as represented by Figures 9 and 10. A laser beam 138,

represented by a solid line in Figure 9 and a dot in

Figure 10, can form the blade out of a section of stock 132 in a single pass. As seen in Figure 9, the beam 138 is emitted from a laser 136 so as to be perpendicular to the plane of the face of the stock 132 from which the blade 60 is formed. In Figure 9, the stick 132 is shown resting on bed 140 formed from aluminum. In Figure 10, the cut in the stock to form the blade 60 is seen as a solid line 142. Dashed line 144

represents the pattern where the stock 132 needs to be cut to complete the process of fabricating the blade 60.

[00044] The surfaces of the blade between the side

surfaces 70 are all perpendicular to the side surfaces.

Accordingly, there is no need to, after the blade is initially shaped, subject the blade to an additional shaping process so as to form tapered surfaces that extend from the side

surfaces. Since there is no need to subject a blade to these additional shaping processes, the blade of this invention can be more economical to manufacture than blades that must be subjected to these added processes. [00045] It should be understood that the foregoing is directed to a specific embodiment of this invention. Other versions of the invention may have features different from what has been described.

[00046] For example, there is no requirement that in all versions of the invention tabs that extend outwardly from the body of the blade be the feature of the blade 60 that

facilitate the releasable coupling of the blade to the saw 30. In alternative versions of the invention, the feature of the blade that facilitates the coupling of the blade to the saw by may be one or more openings in the blade body. Alternatively, the feature of the blade body that facilitates the releasable coupling of the blade may be providing the blade body with a proximal section that has specific dimensions. These

dimensions facilitate the seating of the blade in the

complementary blade mount 42.

[00047] Likewise, there is no requirement that all versions of the invention include the teeth illustrated with respect to the described embodiment of the invention. For example, there is no requirement that the inner perimeter of the head of the teeth be defined by a step that is planar. In some versions of the invention, the surface that defines this perimeter may be curved. If the step is planar, the step may not be

parallel to the longitudinal axis through the blade body. The step may be angled relative to longitudinal axis through the blade body. Typically, if a tooth of this invention has this type of shape, the tooth is shaped so, as the surface that defines the inner perimeter of the tooth head extends

proximally, the surface extends inwardly, towards the

longitudinal axis of the blade body 62.

[00048] Similarly, there is no requirement that in all versions of the invention a planar rake surface serve as the common distal perimeter of both the base 82 of a tooth 80 and the contiguous head 98 of the tooth. In some versions of the invention, this surface will be a common rake surface that, instead of being planner, is curved. In some versions of the invention, the distally directed surface of the base of the tooth and the contiguous adjacent rake surface of the head of the tooth may be two distinct surfaces. Typically, in

versions of the invention in which the teeth have this

geometry, a single tooth is formed so that, relative to line perpendicular to the longitudinal through the blade body 62, the acute angle of the rake surface integral with the head of the tooth is greater than the acute angle of the contiguous distally directed surface of the associated base of the tooth.

[00049] Further there is no requirement that, in all

versions of the invention, the primary teeth have a common shape. In other words, not all of the primary teeth may be shaped to have the tooth base and tooth head of this

invention. Some reciprocating saw blades of this invention may be designed so to have one or more primary teeth of this invention that are interleaved with teeth that are shaped differently. It should thus be appreciated that in these versions of the invention, the primary tooth with the above described base and head and the proximally adjacent tooth will still form a chip catchment for the proximally adjacent tooth. Thus reciprocating saw blades that fall within the scope of this invention includes blades wherein: each tooth with a base and head alternates with another tooth; plural teeth with a base and head alternative with plural teeth that have an alternative shape; a single tooth with a base and head is disposed between on either side of that tooth, plural teeth that have an alternative shape.

[00050] Likewise, while in many versions of the invention, the surfaces between the side surfaces 70 are all perpendicular to the side surfaces, all blades of this invention may not have this feature.

[00051] Further while many versions of blade 60 are designed to be of narrow thickness to facilitate the use of the blade with a small bone resection guide, not all blades of this invention may be so designed. Thus it is within the scope of some versions of this invention the blade have a thickness greater than the maximum thickness of the blades that are used with small bone resection guides.

[00052] Also while the blade is normally intended for attachment to a powered saw, the use of the blade is not so limited. It is within the scope of this invention that the blade be attached to a manual saw. This is a saw that

includes a handle that is used to hold and manually press and reciprocate the blade against the tissue the blade is used to cut. Thus, for the purposes of this invention, a saw should be interpreted to include a handle that can be attached to the blade to facilitate the manual reciprocation of the blade.

[00053] Further there is no requirement that this blade always be formed in a laser cutting process wherein the cutting beam is always perpendicular to the face of the stock from which the blade is formed.

[00054] Accordingly, it is an object of the appended claims to cover all variations and modifications that come within the true spirit and scope of this invention.

Claims

What is claimed is:

1. A surgical saw blade (60), said saw blade including: an elongated body (62) having opposed sides

surfaces (70), a proximal end, a distal end, a longitudinal axis that extends between the proximal and distal ends; and, between the side surfaces, opposed top and bottom surfaces (68, 72);

a feature (74) adjacent the proximal end of the

body (60), the feature configured for releasably attaching the body to a saw (30) capable of reciprocating the body along the longitudinal axis of the body so the blade can perform a surgical procedure; and

a plurality of the teeth (80) that extend outwardly from the bottom surface (72) of the blade body (62), each tooth having a rake surface (84) and a clearance surface (88) that meet to form a cutting edge (86),

characterized in that:

at least one tooth is formed to have a base (82) located proximal to the longitudinal axis of the blade body (62) and a head (98) that extends outwardly from said base, said head including the rake surface (84), the cutting edge (86) and the clearance surface (88) of the tooth and wherein said base has an outer portion with a proximal-to-distal width that less than the proximal-to-distal width of an adjacent section of said head (98) so that said tooth has a step (90) that extends distally forward from an end of the clearance surface (88) closest to the longitudinal axis of the blade body, the step at least partially defining a chip catchment (108) between the said tooth (80) and a proximally adjacent tooth, wherein the proximal to distal length of an opening (106) into the chip catchment is less than the proximal-to-distal length of the opening (102) between the cutting edges (86) of the tooth and the proximally adjacent tooth.

2. The saw blade (60) of Claim 1, wherein said at least one tooth (80) is formed so that the rake surface (84) extends inwardly toward the blade body (62) so an inner section of the rake surface functions as a distally directed surface of said base (82) of said tooth.

3. The saw blade (60) of Claims 1 or 2, wherein said at least one tooth (80) is formed so the rake surface (84) is planar in shape.

4. The saw blade (60) of any one of Claims 1 to 3 wherein, said at least one tooth (80) wherein is further formed so that the step (90) is planar in shape.

5. The saw blade (60) of Claim 4, wherein said at least one tooth (80) is further formed so that the step (90) is located on a plane that is parallel to the longitudinal axis of the blade body (62) .

6. The saw blade (60) of any one of Claims 1 to 5, wherein said at least one tooth (80) is further formed so as to have trailing surface (92) that defines a proximal end of said base (80) of said tooth, said trailing surface extending from the blade body (62) to a distal end of the step (90) .

7. The saw blade (60) of Claim 6, wherein said at least one tooth (80) is further formed so that, as the trailing surface (92) of the base (82) of said tooth extends away from the blade body (62) the trailing surface extends distally forward .

8. The saw blade of Claims 6 or 7, wherein said at least one tooth (80) is further formed so that the trailing surface (92) of the base (80) of said tooth is planar in shape .

9. The saw blade (60) of any one of Claims 1 to 8, wherein at least two said teeth (80) each having said

base (82), said head (92) and the step surface (90) extend outwardly from the blade body.

10. The saw blade of Claim 9, wherein the at least two said teeth (80) are adjacent each other.

11. The saw blade of any one of Claims 1 to 10, wherein: a head (76) extends forward from the distal end of said blade body; and

supplemental teeth (78) extend outwardly from said head (76) .

12. The saw blade of any one of Claims 1 to 11, wherein the feature for releasably attaching the body (62) to a saw consists of at least one tab (74) that extends outwardly from one of the top surface (68) or bottom surface (72) of the body .

13. The saw blade of any one of Claims 1 to 9, wherein said at least one tooth (80) is formed so that the rake surface (84), the clearance surface (88) and the step (90) of the said at least one tooth (80) are in planes that are perpendicular to planes of the opposed side surfaces (70) of the blade body (62) .