WO2013119148A1

WO2013119148A1 - Cutting blade for cutting apparatus

Info

Publication number: WO2013119148A1
Application number: PCT/SE2012/050105
Authority: WO
Inventors: Ulrik Gejervall
Original assignee: Husqvarna Ab
Priority date: 2012-02-06
Filing date: 2012-02-06
Publication date: 2013-08-15

Abstract

A cutting blade 3 for a cutting apparatus 1 is provided, wherein the cutting blade 3 extends in a longitudinal direction 5 and a transverse direction 7. The cutting blade 3 comprises a first surface 9, arranged to be in sliding contact with a second surface 11 of the cutting apparatus 1. The first surface 9 comprises a sliding portion 21 and a cutting portion 23, wherein the cutting portion 23 comprises a plurality of cutting teeth 13 arranged at spaced intervals. The first surface 9, at least in the sliding portion 21, is provided with at least one depression 25, so as to reduce friction between the first surface 9 and the second surface, wherein the at least one depression 25 has been produced by laser machining. The present invention also relates to a method of manufacturing a cutting blade for a cutting apparatus.

Description

CUTTING BLADE FOR CUTTING APPARATUS

TECHNICAL FIELD

The present invention relates to a cutting blade for a cutting apparatus. The present invention further relates to a method of manufacturing a cutting blade for a cutting apparatus.

BACKGROUND

With a cutting apparatus such as a hedge trimmer, an operator may cut vegetation, such as bushes, branches, grass etc. A hedge trimmer may comprise two cutting blades, reciprocating relative to each other along a longitudinal axis, wherein a relative motion between the two cutting tools may perform a cutting motion. Also, a hedge trimmer may comprise one reciprocating cutting tool, e.g. cutting blade, cooperating with a stationary cutting tool to perform cutting. The blades may be driven by means of a motor, e.g. an electrical motor or a combustion engine. Typically, a transmission transmits power from the motor to the cutting blades. In operation, the reciprocating relative motion and contact surfaces between the blades causes friction. The friction may cause heat generation and premature wear of the cutting blades. Further, as a result of grease leaking out of the transmission and/or resin from vegetation staying between the blades, extra power is needed to start the reciprocating motion of the blades when the cutting apparatus is cold.

Attempts have been made to reduce friction between the reciprocating cutting blades. For example, lubrication oil circuits have been employed to introduce lubricant oil between the blades during operation. This solution involves a number of drawbacks. Primarily, in terms of environmental concerns, there is a risk that lubricant oil leaks out from the cutting blades during cutting to thereby pollute the nearby surroundings. Also, the lubricant oil may attract dust and debris during operation and the lubrication oil circuit requires a pump and driving means for the same which adds complexity to the cutting apparatus and thereby increases manufacturing costs. The document WO201 1088846 reveals a method and system for reducing friction between two reciprocating blades of a cutting apparatus. A sliding portion of the cutting blade is provided with embossments which extend outwardly from the sliding portion. Due to the embossments, in the sliding portion a contact area between the cutting blades is reduced. During operation, the friction between the cutting blades of the cutting apparatus is reduced due to the reduction in contact area.

SUMMARY

An object of the present invention is to provide a cutting blade for a cutting apparatus wherein an improved friction characteristic between a surface of the cutting blade and a second surface of the cutting apparatus is achieved at low cost.

According to an aspect of the invention, the object is achieved by a cutting blade for a cutting apparatus, wherein the cutting blade extends in a longitudinal and a transverse direction. The cutting blade comprises a first surface, arranged to be in sliding contact with a second surface of the cutting apparatus. The first surface comprises a sliding portion and a cutting portion, wherein the cutting portion comprises a plurality of cutting teeth arranged at spaced intervals. The first surface, at least in the sliding portion, is provided with at least one depression, so as to reduce friction between the first and second surfaces. The at least one depression has been produced by laser machining.

Since the first surface, at least in the sliding portion, is provided with at least one depression produced by laser machining, friction between the first and second surfaces is reduced. As a result, the above mentioned object is achieved.

According to some embodiments, the cutting blade has been laser cut from sheet metal using a laser machining apparatus. The at least one depression may be produced using said laser machining apparatus. Thus, the same laser machining apparatus used to laser cut the cutting blade from raw material may be used for producing the at least one depression. Therefore, a number of manufacturing steps may be reduced in comparison with prior art methods for providing a cutting blade with e.g. friction reduction features. As a result, a number of machines required to produce a cutting blade may also be reduced as well as a number of intermediate production steps. Therefore, a fast and cost efficient production of the cutting blade and the at least one depression may be achieved.

Also, since the at least one depression has been produced by laser machining, the first surface may be hardened in a region of the at least one depression due to a temperature increase in this region during the laser machining. As a result, premature wear of the cutting blade may be avoided and the at least one depression may be provided with hardened edges. A distance between the cutting portion of the first surface and the second surface may affect a cutting result. Generally, a small distance between these surfaces results in a good cutting result. Since the first surface of the cutting blade is provided with a depression, a small distance between the first surface and the second surface is achieved. As a result, friction between the first and second surfaces is reduced, while a good cutting result is achieved.

The feature "reduce friction" is intended to encompass a friction reduction between the first surface and the second surface during operation of the cutting apparatus, as well as a friction reduction during a start-up phase of the cutting apparatus. That is, the at least one depression in the first surface in at least the sliding portion produced using a laser machining apparatus may reduce a coefficient of kinetic friction as well as a coefficient of static friction between the first surface and the second surface. The reduction of friction may be a result of a reduction of a coefficient of friction of the cutting blade per se or a result of the at least one depression promoting removal of matter caught between the surfaces and/or the at least one depression helping to draw in air between the surfaces.

According to some embodiments, a depth of the at least one depression is less than or equal to 0.5 mm from the first surface. In such embodiments, the depth of the at least one depression may be between 0.2 mm and 0.5 mm from the first surface. The at least one depression may promote removal of matter such as resin or sap from plants, and/or dust and debris caught between the first surface and the second surface. Due to the promotion of removal of matter between the first surface and the second surface, friction between the surfaces may be reduced. Further, matter caught between the surfaces may affect abutment between the surfaces such that a tolerance between the cutting portion of the first surface and the second surface is deteriorated which may lead to an inferior cutting result. Due to the promotion of removal of matter between the first surface and the second surface, the cutting result may be improved. Further, via the at least one depression air may be drawn in between the first surface and the second surface and may thereby reduce friction between the surfaces.

According to some embodiments, at least one protrusion, adjacent to the at least one depression, has been produced by laser machining. In such embodiments, the at least one protrusion may be formed by the laser machining when producing the at least one depression. The at least one protrusion may be formed by at least one ridge formed by said laser machining. The at least one protrusion may further reduce friction between the first and second surfaces.

According to some embodiments, both the sliding portion and the cutting portion are provided with the at least one depression, so as to reduce friction between the first surface and the second surface. In such embodiments, a larger area of the first surface may be provided with the at least one depression. As a result, a further reduction of friction between the first and second surface may be achieved. Also, in embodiments wherein a larger area is provided with the at least one depression, a larger area may be hardened due to a temperature increase in the first surface during the laser machining. Thereby, premature wear of the cutting blade may be further avoided.

According to some embodiments, the at least one depression of the first surface comprises a number of dents. Both the sliding portion and the cutting portion of the cutting blade may be provided with the dents.

According to some embodiments, the at least one depression of the first surface comprises at least one trace. The at least one trace may form a pattern extending both in the longitudinal direction and in the transverse direction of the cutting blade.

According to some embodiments, the at least one trace extends to an outer end of the first surface. The extension of the trace to an outer end of the first surface may let air in between the first surface and the second surface and may promote removal of matter caught between the first surface and the second surface. According to some embodiments, the at least one depression comprises at least one cavity. The at least one cavity may reduce friction between the first surface of the cutting blade and the second surface and may promote removal of matter caught between the first surface and the second surface. Also, via the at least one cavity air may be drawn in between the first surface and the second surface and may thereby reduce friction between the surfaces.

According to some embodiments, the at least one cavity extends in the longitudinal direction of the cutting blade, between at least two teeth of the plurality of cutting teeth.

According to some embodiments, the at least one cavity extends to an outer end of the first surface. According to some embodiments, the at least one cavity extends to an outer end of at least one tooth of the plurality of cutting teeth. Thus, according to such embodiments, the at least one cavity may promote removal of matter caught between the first surface and the second surface, wherein the promoting of removal of matter may lead to a removal of matter to a region of an outer end of at least one tooth of the plurality of cutting teeth.

According to some embodiments, the cutting blade comprises at least one through hole in a region of the at least one depression. The cutting blade may comprise two or more through holes provided in the cutting portion and/or the sliding portion of the first surface. The at least one through hole may be produced by laser machining using a laser machining apparatus. The at least one through hole may promote removal of matter caught between the first surface and the second surface and may thereby reduce friction between these surfaces. Also, the at least one through hole may supply air in between the first surface and the second surface and may thereby reduce friction between these surfaces.

According to some embodiments, the cutting blade comprises a third surface opposite to the first surface, wherein the third surface is provided with at least one third depression, so as to reduce friction between the third surface and a fourth surface of the cutting apparatus, and wherein the at least one third depression has been produced by laser machining. The fourth surface of the cutting apparatus may be a surface of a first guide rail abutting against the third surface of the cutting blade. According to some embodiments, the cutting apparatus is a power-driven hand-held cutting apparatus, such as a hedge trimmer.

According to some embodiments, the cutting apparatus is a power-driven hand-held cutting apparatus comprising a second cutting blade, wherein the second surface is a surface of the second cutting blade. The second cutting blade may be a cutting blade according to any of the embodiments described herein. That is, the second surface of the second cutting blade may be provided with a depression and/or protrusion produced by laser machining as described in connection with embodiments related to the cutting blade. Accordingly, in such embodiments, the cutting apparatus comprises a first cutting blade and a second cutting blade. The second cutting blade may be provided with the same type of depression as the first cutting blade or may be provided with a depression of a different type than the first cutting blade. Thus, according to some embodiments, the second cutting blade is provided with similar features as the first cutting blade. According to some embodiments, the at least one depression of the first surface and at least one second depression of the second surface each comprises at least one trace, and wherein the traces extend at least partially substantially in the transverse direction of the cutting blades, such that a direction of the trace of the first surface is different from a direction of the trace of the second surface when the surfaces abut against each other when arranged in the cutting apparatus. A portion of the traces may cross each other in at least one intersection when the two surfaces abut against each other. During a relative motion between the first surface and the second surface, the crossing may further reduce friction between these surfaces and may further promote removal of matter caught between these surfaces and may further draw in air between these surfaces.

According to an aspect of the invention, the object is achieved by, a method of manufacturing a cutting blade for a cutting apparatus, wherein the cutting blade extends in a longitudinal and a transverse direction. The cutting blade comprises a first surface arranged to be in sliding contact with a second surface of the cutting apparatus. The first surface comprises a sliding portion and a cutting portion. The cutting portion comprises a plurality of cutting teeth arranged at spaced intervals,

wherein the method comprises;

producing at least one depression in the first surface in at least the sliding portion using a laser machining apparatus, so as to reduce friction between the first and second surfaces.

Again, since at least one depression in the first surface in at least the sliding portion is produced using a laser machining apparatus, friction between the first and second surfaces is reduced. Furthermore, thanks to the use of laser machining, a flexible and streamlined production of the cutting blade is achieved. Thereby, manufacturing costs of the cutting blade are reduced. As a result, the above mentioned object is achieved. Also, since the at least one depression has been produced by laser machining, the first surface may be hardened in a region of the at least one depression due to a temperature increase in this region during the laser machining. As a result, premature wear of the cutting blade may be avoided and the at least one depression may be provided with hardened edges.

Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following detailed description. Those skilled in the art will realize that different features of the present invention may be combined to create embodiments other than those described in the following, without departing from the scope of the present invention, as defined by the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The various aspects of the invention, including its particular features and advantages, will be readily understood from the following detailed description and the accompanying drawings, in which:

Fig. 1 illustrates a hand-held cutting apparatus according to some embodiments. Fig. 2 - Fig. 5 illustrate cutting blades for cutting apparatuses according to some embodiments.

Fig. 6 illustrates a method of manufacturing a cutting blade for a cutting apparatus according to some embodiments.

DETAILED DESCRIPTION

The present invention will now be described more fully with reference to the

accompanying drawings, in which example embodiments are shown. However, this invention should not be construed as limited to the embodiments set forth herein.

Disclosed features of example embodiments may be combined as readily understood by one of ordinary skill in the art to which this invention belongs. Like numbers refer to like elements throughout. Well-known functions or constructions will not necessarily be described in detail for brevity and/or clarity.

Fig. 1 illustrates a hand-held cutting apparatus 1 according to some embodiments. The cutting apparatus 1 is a motor-driven hand-held hedge trimmer. The cutting apparatus 1 comprises a first cutting blade 3 extending in a longitudinal direction 5 and a transverse direction 7. The first cutting blade 3 has a first surface 9 arranged to be in sliding contact with a second surface 1 1 of the cutting apparatus 1 . The first surface 9 of the first cutting blade 3 comprises a sliding portion and a cutting portion, wherein the cutting portion comprises a plurality of cutting teeth 13 arranged at spaced intervals. The longitudinal direction 5 extends along the cutting blade 3 substantially transverse to the cutting teeth 13. The transverse direction 7 extends substantially perpendicularly to the longitudinal direction 5. The cutting apparatus 1 further comprises a motor, in the form of a combustion engine. Alternatively, the cutting apparatus 1 may comprise an electric motor. As explained below, the first cutting blade 3 may be driven, in a reciprocating motion along the longitudinal direction 5, by the motor.

The cutting apparatus 1 comprises a second cutting blade 15 extending in the longitudinal direction 5 and the transverse direction 7. The second cutting blade 15 comprises the second surface 1 1 arranged to be in sliding contact with the first surface 9 of the first cutting blade 3. The second surface 1 1 may comprise a sliding portion and a cutting portion, wherein the cutting portion comprises a plurality of cutting teeth 17 arranged at spaced intervals. The second cutting blade 15 may also be driven by the motor in a reciprocating motion. Alternatively, the second cutting blade 15 may be fixed in relation to the cutting apparatus 1 . In both cases, a relative motion between the first cutting blade 3 and the second cutting blade 15 performs a cutting motion. The first surface 9 of the cutting blade 3 is provided with at least one depression, at least in the sliding portion, so as to reduce friction between the first surface 9 and the second surface 1 1 , wherein the at least one depression has been produced by laser machining. Due to the reduced friction between the first surface 9 and the second surface 1 1 , a starting force required to start the reciprocating motion of the cutting blade 3 may be reduced. Also, during operation of the cutting apparatus 1 , the power of the motor, required to drive the cutting blade 3 in the reciprocating motion may be reduced. Further, due to the reduced friction, heat generation and premature wear of the cutting blade 3 may be avoided. Also, the at least one depression may draw air in between the first surface 9 and the second surface 1 1 to thereby avoid a binding between these surfaces. The at least one depression provided in the first surface 9 of the first cutting blade 3 may promote removal of matter such as resin or sap from plants, grease, and/or dust and debris caught between the first surface 9 and the second surface 1 1 . Due to the promotion of removal of matter between the first surface 9 and the second surface 1 1 friction between these surfaces 9, 1 1 may be reduced. Further, the promotion of removal of matter between the first surface 9 and the second surface 1 1 may ensure that a distance between these surfaces 9, 1 1 is maintained such that a distance between the cutting portion of the first surface 9 and the cutting portion of the second surface 1 1 is maintained. Thereby, a good cutting result may be maintained over time.

According to some embodiments, the second surface 1 1 of the second cutting blade 15 is provided with at least one second depression, at least in the sliding portion, so as to reduce friction between the first surface 9 and the second surface 1 1 , wherein the at least one second depression has been produced by laser machining. Since both the first surface 9 and the second surface 1 1 is provided with at least one depression, friction between these surfaces may be reduced. According to some embodiments, the cutting blade 3 comprises a third surface 19 opposite to the first surface 9, wherein the third surface 19 is provided with at least one third depression, so as to reduce friction between the third surface 19 and a fourth surface 24 of the cutting apparatus 1 , and wherein the at least one third depression has been produced by laser machining. In such embodiments, the fourth surface 24 of the cutting apparatus 1 may be a surface of a first guide rail 22 abutting against the third surface 19 of the cutting blade 3. Further, the fourth surface 24 of the first guide rail 22 may be provided with at least one fourth depression so as to reduce friction between the fourth surface 24 and the third surface 19 of the cutting blade 3. The at least one fourth depression may be produced by laser machining.

The sliding portion of the first cutting blade 3 and the second cutting blade 15 may be provided with slots having an extension essentially in the longitudinal direction 5 of the cutting blades 3, 15. In such embodiments, bolts 29 are provided extending through the slots of the blades 3, 15 to thereby hold together at least the first guide rail 22, the first cutting blade 3, and the second cutting blade 15. The slots extend essentially in the longitudinal direction 5 of the blades 3, 15 and allow a reciprocating motion of the cutting blades in the longitudinal direction 5. In embodiments wherein the second cutting blade 15 is fixed in relation to the cutting apparatus, the bolts may be fixed in relation to the second cutting blade 15 and slots provided in a sliding portion of the first cutting blade 3 may permit a reciprocating motion of the first cutting blade 3 in the longitudinal direction 5. A purpose with the first guide rail 22 may be to guide the first cutting blade 3 and/or the second cutting blade 15 in the reciprocating motion along the longitudinal direction 5. Fig. 2 illustrates a cutting blade 3 for a cutting apparatus according to some

embodiments. The cutting blade 3 extends in a longitudinal direction 5 and a transverse direction 7. The cutting blade 3 comprises a first surface 9, arranged to be in sliding contact with a second surface of the cutting apparatus. The second surface may be a surface of a second cutting blade. The first surface 9 of the cutting blade 3 comprises a sliding portion 21 and a cutting portion 23, wherein the cutting portion 23 comprises a plurality of cutting teeth 13 arranged at spaced intervals. The first surface 9 of the cutting blade 3 may comprise one or more cutting portions. The first surface 9, at least in the sliding portion 21 , is provided with at least one depression 25, so as to reduce friction between the first surface 9 and the second surface. The at least one depression 25 has been produced by laser machining. The at least one depression 25 of the first surface 9 comprises a number of dents 26. The dents 26 are provided at least in the sliding portion 21 . As illustrated in Fig. 2 the dents 26 may be provided both in the sliding portion 21 and in the cutting portion 23. Further, the dents 26 may be provided in substantially the entire first surface 9 of the cutting blade 3. The feature "dents" is intended to cover small- size depressions produced by laser machining. A diameter of a dent 26 may be in the range of 0.1 -1 mm and a depth of a dent to the first surface 9 may be in the range of 0.1 - 0.5 mm. According to some embodiments, a protrusion has been produced by laser machining adjacent to substantially each dent. In such embodiments, the protrusions may be formed by ridges, formed by said laser machining, at least partially encircling the dents 26. The protrusions may further reduce friction between the first and second surface. A height of a protrusion above the first surface 9 may be up to 0.5 mm above the first surface 9. According to some embodiments a height of a protrusion may be considerably less than a depth of a depression 25. The sliding portion 21 of the cutting blade 3 is provided with at least one slot 27. The slot 27 may be adapted to receive a bolt to extend there through to thereby position the cutting blade 3 in relation to the second cutting blade. The longitudinal extension of the slot 27 permits the cutting blade 3 to reciprocate in the longitudinal direction 5 when the bolt extends through the slot 27. Fig. 3 illustrates a cutting blade 3 for a cutting apparatus according to some

embodiments. The cutting blade 3 extends in a longitudinal direction 5 and a transverse direction 7. The cutting blade 3 comprises a first surface 9, arranged to be in sliding contact with a second surface of the cutting apparatus. The second surface may be a surface of a second cutting blade. The first surface 9 of the cutting blade 3 comprises a sliding portion 21 and a cutting portion 23, wherein the cutting portion 23 comprises a plurality of cutting teeth 13 arranged at spaced intervals. The first surface 9, at least in the sliding portion 21 , is provided with at least one depression 25, so as to reduce friction between the first surface 9 and the second surface. The at least one depression 25 has been produced by laser machining. The at least one depression of the first surface 9 comprises at least one trace 31 . The at least one trace 31 forms a pattern extending both in the longitudinal direction 5 and in the transverse direction 7 of the cutting blade 3. As an alternative, the at least one trace 31 may extend substantially exclusively in the longitudinal direction 5 or may extend substantially exclusively in the transverse direction 7 of the cutting blade 3. The at least one trace 31 may be formed by one trace or a plurality of traces. The at least one trace 31 may be formed by providing a relative motion between the first surface 9 and a laser head of the laser machining apparatus to thereby produce a depression 25 in the first surface 9 in the form of a trace 31 . During the laser machining, at least one protrusion 33 may be produced, adjacent to the at least one trace 31 . In such embodiments, the at least one protrusion 33 may be formed by ridges formed by said laser machining. The protrusions may reduce friction between the first surface 9 and second surface. A protrusion 33 may extend to a height of up to 0.5 mm above the first surface 9. According to some embodiments, a height of a protrusion 33 may be considerably less than a depth of the depression 25 forming the at least one trace 31 .

According to some embodiments, the at least one trace 31 extends to an outer end 35, 37, 41 of the first surface 9. In such embodiments, the extension of the trace 31 to an outer end 35, 37, 41 of the first surface 9 may let air in between the first surface 9 and the second surface. As a result, friction between the first surface 9 and the second surface may be reduced. Further, the extension of the trace 31 to an outer end 35, 37, 41 of the first surface 9 may promote removal of matter caught between the first surface 9 and the second surface, such as resin or sap from plants, and/or dust and debris. Promoting removal of matter caught between the first surface 9 and the second surface may reduce friction between these surfaces. When the cutting apparatus is at a standstill, resin or sap from plants may form a bond between the first surface 9 and the second surface. The at least one depression 25 and/or protrusion 33 provided in the first surface 9 may help to break the bond when the cutting apparatus is to be started up. The at least one trace 31 may extend to an outer end 37 of at least one tooth 39 of the plurality of cutting teeth 13. The at least one trace 31 may further extend to an outer end 41 of the sliding portion 21 of the first surface 9 of the cutting blade 3. The sliding portion 21 of the cutting blade 3 is provided with at least one slot 27. The slot 27 may be adapted to receive a bolt extending therethrough to thereby hold the cutting blade 3 against the second cutting blade. The longitudinal extension of the slot 27 may permit the cutting blade 3 to reciprocate in the longitudinal direction 5. As illustrated in Fig. 3, the at least one trace 31 may extend to an outer end 35 of the first surface 9 in the slot 27. According to some embodiments, the cutting blade 3 comprises at least one through hole 43 in the region of the at least one depression 25. Accordingly, the cutting blade 3 may comprise at least one through hole 43 in the region of the at least one depression 25 formed by the at least one trace 31 . The at least one through hole 43 forms an open connection between the first surface 9 of the cutting blade 3 and a third surface 19 of the cutting blade 3 opposite to the first surface 9. The at least one through hole 43 may promote removal of matter caught between the first surface 9 and the second surface and may thereby reduce friction between these surfaces. Also, the at least one through hole 43 may supply air in between the first surface 9 and the second surface and may thereby reduce friction between these surfaces. The cutting blade 3 may comprise two or more through holes provided in the cutting portion 23 and/or the sliding portion 21 of the first surface 9. The at least one through hole 43 may be produced by laser machining using a laser machining apparatus. According to some embodiments, the cutting apparatus is a power-driven hand-held cutting apparatus comprising a first cutting blade and a second cutting blade wherein the second surface is a surface of the second cutting blade. The first cutting blade and the second cutting blade may be a cutting blade 3 as described in any of the embodiments herein, e.g. a cutting blade 3 as shown in Fig. 3.

According to some embodiments, the at least one depression 25 of the first surface 9 and at least one second depression of the second surface 1 1 each comprises at least one trace, and the traces extend at least partially substantially in the transverse direction 7 of the cutting blades 3, 15, such that a direction of the trace of the first surface 9 is different from a direction of the trace of the second surface 1 1 when the surfaces 9, 1 1 abut against each other when arranged in the cutting apparatus. In such embodiments a portion 45 of the trace 31 , provided in the first surface 9 and extending substantially in the transverse direction 7, may extend in a direction different from a portion of a trace provided in the second surface when the two surfaces abut against each other. In such embodiments, the portion 45 of the traces may cross each other in at least one intersection when the two surfaces abut against each other. During a relative motion between the first surface 9 and the second surface, the at least one intersection moves in substantially the transverse direction 7. This may further reduce friction between the surfaces and may further promote removal of matter caught between the surfaces. The first surface 9 and the second surface may be provided with a plurality of traces crossing in a plurality of intersections. Portions 45 having different directions may be achieved e.g. by the first and second cutting blades 3, 15 being provided with portions 45 of the trace extending in the same direction when viewed side by side with their respective longitudinal direction aligned and with the first and second surfaces 9, 1 1 facing in the same direction. When the first and second surfaces 9, 1 1 are positioned with their respective longitudinal direction aligned and such that the first and second surfaces 9, 1 1 abut each other, different directions of the portions 45 of the traces are achieved. For instance, the first cutting blade and the second cutting blade may be a cutting blade 3 as illustrated in Fig 3. In such embodiments, when the first and second cutting blades are viewed side by side with their respective longitudinal direction aligned and with the first and second surfaces facing in the same direction, the first and second cutting blades is provided with portions 45 of the trace extending in the same direction. When the first and second surfaces are positioned with their respective longitudinal direction aligned and such that the first and second surfaces abut each other, different directions of the portions 45 of the traces are achieved.

Fig. 4 illustrates a cutting blade 3 for a cutting apparatus according to some

embodiments. The cutting blade 3 extends in a longitudinal direction 5 and a transverse direction 7. The cutting blade 3 comprises a first surface 9, arranged to be in sliding contact with a second surface of the cutting apparatus. The second surface may be a surface of a second cutting blade. The first surface 9 of the cutting blade 3 comprises a sliding portion 21 and a cutting portion 23, wherein the cutting portion 23 comprises a plurality of cutting teeth 13 arranged at spaced intervals. At least in the sliding portion 21 , the first surface 9 is provided with at least one depression 25, so as to reduce friction between the first surface 9 and the second surface. The at least one depression 25 has been produced by laser machining. The at least one depression 25 comprises at least one cavity 47. The at least one cavity 47 may reduce friction between the first surface 9 of the cutting blade 3 and the second surface and may promote removal of matter caught between the first surface 9 and the second surface. Further, via the at least one cavity 47 air may be drawn in between the first surface 9 and the second surface and may thereby reduce friction between the surfaces. As illustrated in Fig. 4, the at least one cavity 47 may have an extension such that the at least one cavity 47 is provided both in the sliding portion 21 and in the cutting portion 23. A depth of the at least one cavity 47 may be in the range 0.1 -0.7 mm from the first surface 9. The depth of the at least one cavity 47 may be in the range of 0.2-0.5 mm. The at least one cavity 47 has a substantially larger extension both in the longitudinal direction 5 and the transverse direction 7 than the depth of the at least one cavity 47. According to some embodiments, one of the at least one cavities 47 forms a first area 49 of the first surface 9, and one cutting tooth 13 of the plurality of cutting teeth 13 forms a second area 51 of the first surface 9, wherein a size of the first area 49 is larger than one-fifth of a size of the second area 51 . A ratio between the first area 49 and the second area 51 may be in the range of 0.6-0.2. According to some embodiments, the cutting blade 3 is provided with a plurality of cavities, wherein each cavity 47 is provided in a region of a base of a tooth 13. In such embodiments, the cutting blade 3 may comprise an equal number of cavities 47 and teeth 13.

According to some embodiments, the cutting blade 3 comprises at least one through hole 43 in the region of the at least one cavity 47. The at least one through hole 43 in the region of the at the at least one cavity 47 may further reduce friction between the first surface 9 and the second surface and may promote removal of matter caught between the surfaces and/or to provide air between the surfaces. In embodiments wherein the cutting blade 3 comprises a plurality of cavities, the cavities may comprise one or more through holes each. The at least one through hole 43 may be produced by laser machining and may be provided in the sliding portion 21 and/or in the cutting portion 23.

Fig. 5 illustrates a cutting blade 3 for a cutting apparatus according to some

embodiments. The cutting blade 3 extends in a longitudinal direction 5 and a transverse direction 7. The cutting blade 3 comprises a first surface 9, arranged to be in sliding contact with a second surface of the cutting apparatus. The second surface may be a surface of a second cutting blade. The first surface 9 of the cutting blade 3 comprises a sliding portion 21 and a cutting portion 23, wherein the cutting portion 23 comprises a plurality of cutting teeth 13 arranged at spaced intervals. At least in the sliding portion 21 , the first surface 9 is provided with at least one depression 25, so as to reduce friction between the first surface 9 and the second surface. The at least one depression 25 has been produced by laser machining. The at least one depression 25 comprises at least one cavity 47 extending in the longitudinal direction 5 of the cutting blade 3, between at least two teeth 13 of the plurality of cutting teeth 13. The at least one cavity 47 may reduce friction between the first surface 9 of the cutting blade 3 and the second surface and may promote removal of matter caught between the first surface 9 and the second surface. According to some embodiments, the at least one cavity 47 extends to an outer end 53 of the first surface 9 and the at least one cavity 47 may extend to an outer end 53 of at least one tooth 13 of the plurality of cutting teeth 13. As an alternative, the at least one cavity 47 may extend to an outer end of the sliding portion 21 of the first surface 9 of the cutting blade 3 and/or may extend to an outer end of the first surface 9

communicating with a slot 27 provided in the sliding portion 21 of the cutting blade 3. The extension of the at least one cavity 47 to an outer end of the first surface 9 may promote removal of matter caught between the first surface 9 and the second surface and may draw in air between these surfaces.

In further embodiments, the cutting blade 3 is provided with at least one through hole 43 in a region of the at least one cavity 47. The at least one through hole 43 may be produced by laser machining and may further reduce friction between the first surface 9 and the second surface and may further promote removal of matter caught between these surfaces and air may be drawn in between the surfaces through the at least one through hole 43. The at least one through hole 43 may be provided in the sliding portion 21 and/or in the cutting portion 23.

Fig. 6 illustrates a method of manufacturing a cutting blade for a cutting apparatus according to some embodiments, wherein the cutting blade extends in a longitudinal and a transverse direction and comprises a first surface arranged to be in sliding contact with a second surface of the cutting apparatus. The first surface comprises a sliding portion and a cutting portion, the cutting portion comprising a plurality of cutting teeth arranged at spaced intervals, wherein the method comprises,

- producing 101 at least one depression in the first surface in at least the sliding portion using a laser machining apparatus, so as to reduce friction between the first and second surface.

The method of manufacturing a cutting blade for a cutting apparatus may further comprise;

- producing 102 at least one protrusion in the first surface, adjacent to the at least one depression, using the laser machining apparatus. The at least one protrusion may be formed by the laser machining when producing the at least one depression. The at least one protrusion may be formed by ridges formed by said laser machining. The at least one protrusion may further reduce friction between the first and second surfaces. Since a region of the at least one depression may be hardened during the laser machining, the at least one protrusion may be hardened. According to some embodiments, a height of a protrusion above the first surface may be considerably less than a depth of the depression from the first surface. The method of manufacturing a cutting blade for a cutting apparatus may further comprise;

- producing 103 the at least one depression in the form of a number of dents, using the laser machining apparatus. The method of manufacturing a cutting blade for a cutting apparatus may further comprise;

- providing 104 a relative motion between the first surface and a laser head of the laser machining apparatus to thereby produce a depression in the form of a trace in the first surface when using the laser machining apparatus.

The relative motion between the first surface and the laser head of the laser machining apparatus may be provided by moving the laser head relative to the first surface of the cutting blade. As an alternative, the relative motion between the first surface and the laser head of the laser machining apparatus may be provided by moving the cutting blade comprising the first surface relative to the laser head.

The trace may be produced by providing a relative motion between the first surface and a laser head of the laser machining apparatus to thereby produce a depression in the form of a trace extending to an outer end of the first surface.

- producing 105 the at least one depression in the form of an at least one cavity, using the laser machining apparatus. In such embodiments, the at least one cavity may be produced by providing a relative motion between the first surface of the cutting blade and a laser head of the laser machining apparatus. The relative motion may be provided in a to and fro motion and/or a motion substantially along and parallel with edges of the at least one cavity. That is, the at least one cavity may be produced by a removal of material in the form of a plurality of adjacent traces. The relative motion between the first surface and the laser head of the laser machining apparatus may be provided by moving the laser head in a relative motion to the first surface of the cutting blade. As an alternative, the relative motion between the first surface and the laser head may be provided by moving the cutting blade comprising the first surface in a relative motion to the laser head.

- producing 106 at least one through hole in the region of the at least one

depression.

In such embodiments, the at least one through hole may be produced using the laser machining apparatus. Since the at least one depression has been produced by the laser machining apparatus, producing the at least one through hole with the same apparatus may be a cost efficient manufacturing method. The at least one through hole may form an open connection between the first surface of the cutting blade and a third surface opposite to the first surface. During operation of the cutting device, the open connection may promote removal of matter caught between the first surface and the second surface and may thereby reduce friction between these surfaces. Also, air may be drawn in between the surfaces through the at least one through hole and may thereby reduce friction between these surfaces.

laser cutting 107 the cutting blade from sheet metal, using the laser machining apparatus. That is, according to such embodiments, the same laser machining apparatus used to laser cut the cutting blade from raw material is used for producing the at least one depression. Therefore, a fast and cost efficient producing method of the at least one depression is achieved. Further, according to some embodiments, the laser machining apparatus used to laser cut the cutting blade and for producing the at least one depression, is used for producing at least one protrusion, adjacent to the at least one depression, and/or used for producing at least one through hole in the region of the at least one depression. Thus, the number of manufacturing steps is reduced in comparison with prior art methods for producing a cutting blade with e.g. friction reduction features. As a result, the number of machines required to produce a cutting blade may be reduced and the number of intermediate production steps may also be reduced. The feature "laser cutting the cutting blade from sheet metal" may include laser cutting the outer contours of the cutting blade as well as laser cutting slots in a sliding portion of the cutting blade. A piece of the sheet metal may be used to laser cut a plurality of cutting blades. The cutting blade may be laser cut from sheet metal prior to the producing of the at least one depression in the first surface using the laser machining apparatus. As an alternative, the at least one depression is produced, using the laser machining apparatus, prior to said laser cutting the cutting blade from sheet metal. In such embodiments, the at least one depression is produced in a surface of the sheet metal prior to said laser cutting the cutting blade, wherein the surface of a piece of sheet metal may constitute a basis for several first surfaces of several cutting blades.

Further, the method of manufacturing a cutting blade for a cutting apparatus, as described herein may be performed in any suitable order.

The feature "laser machining" is intended to encompass laser machining methods such as melt and blow or fusion cutting, reactive cutting, burning stabilized laser gas cutting, flame cutting or any other laser machining method appropriate for producing a depression in a surface and/or any other laser machining method appropriate for laser cutting. The feature "laser machining apparatus" is intended to encompass a laser machining apparatus appropriate for conducting one of the laser machining methods mentioned above, e.g. an Amanda LC 2415 alpha III laser machining apparatus. Although the invention has been described with reference to example embodiments, many different alterations, modifications and the like will become apparent for those skilled in the art. For example, the second cutting blade 15 may comprise a fifth surface opposite to the second surface 1 1 , and wherein the fifth surface is provided with at least one fifth depression, so as to reduce friction between the fifth surface and a sixth surface of the cutting apparatus 1 , and wherein the at least one fifth depression has been provided by laser machining. The cutting apparatus 1 may comprise a second guide rail provided with the sixth surface abutting the fifth surface of the second cutting blade 15. A purpose with the first and/or second guide rail may be to guide the cutting blade 3 and/or the second cutting blade 15 in the reciprocating motion. The sixth surface of the second guide rail may be provided with at least one sixth depression so as to reduce friction between the sixth surface and the fifth surface of the second cutting blade 15. The at least one sixth depression may have been produced by laser machining. It is also understood by those skilled in the art that the third surface 19, fourth surface 24, fifth surface and/or sixth surface may be provided with at least one depression in the form of any herein described depression. Also, all the surfaces described herein provided with at least one depression produced by laser machining may comprise at least one protrusion, adjacent to the at least one depression. Further, the at least one depression provided in these surfaces may comprise a number of dents, and/or at least one trace, and/or at least one cavity. Also, the cutting blade, the second cutting blade, the first guide rail and/or the second guide rail may comprise at least one through hole in the region of the at least one depression. It is to be understood that the foregoing is illustrative of various example embodiments and the invention is not to be limited to the specific embodiments disclosed and that modifications to the disclosed embodiments, combinations of features of disclosed embodiments as well as other embodiments are intended to be included within the scope of the appended claims.

As used herein, the term "comprising" or "comprises" is open-ended, and includes one or more stated features, elements, steps, components or functions but does not preclude the presence or addition of one or more other features, elements, steps, components, functions or groups thereof. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. As used herein, the common abbreviation "e.g.", which derives from the Latin phrase "exempli gratia," may be used to introduce or specify a general example or examples of a previously mentioned item, and is not intended to be limiting of such item. If used herein, the common abbreviation "i.e.", which derives from the Latin phrase "id est," may be used to specify a particular item from a more general recitation.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It will be understood that although the terms first, second, third etc. may be used herein to describe various elements and/or components, these elements and/or components should not be limited by these terms. These terms are only used to distinguish one element and/or component from another element and/or component. Thus, a first element and/or component discussed herein could be termed a second element and/or component without departing from the teachings of the present invention.

Claims

A cutting blade (3) for a cutting apparatus (1 ), wherein the cutting blade (3) extends in a longitudinal direction (5) and a transverse direction (7) and comprises:

a first surface (9), arranged to be in sliding contact with a second surface (1 1 ) of the cutting apparatus (1 ), wherein the first surface (9) comprises a sliding portion (21 ) and a cutting portion (23), wherein the cutting portion (23) comprises a plurality of cutting teeth (13) arranged at spaced intervals;

characterized in that the first surface (9), at least in the sliding portion (21 ), is provided with at least one depression (25), so as to reduce friction between the first surface (9) and the second surface (1 1 ), wherein the at least one depression (25) has been produced by laser machining.

The cutting blade (3) according to claim 1 , wherein at least one protrusion (33), adjacent to the at least one depression (25), has been produced by laser machining.

The cutting blade (3) according to claim 1 or 2, wherein both the sliding portion (21 ) and the cutting portion (23) are provided with the at least one depression (25), so as to reduce friction between the first surface (9) and the second surface (1 1 ).

The cutting blade (3) according to any of the claims 1 -3, wherein the at least one depression (25) of the first surface (9) comprises a number of dents (26).

The cutting blade (3) according to any of the claims 1 -3, wherein the at least one depression (25) of the first surface (9) comprises at least one trace (31 ).

The cutting blade (3) according to claim 5, wherein the at least one trace (31 ) forms a pattern extending both in the longitudinal direction (5) and in the transverse direction

(7) of the cutting blade (3).

The cutting blade (3) according to claim 5 or 6, wherein the at least one trace (31 ) extends to an outer end (35, 37, 41 ) of the first surface (9).

8. The cutting blade (3) according to any of the claims 1 -3, wherein the at least one depression (25) comprises at least one cavity (47).

9. The cutting blade (3) according to claim 8, wherein the at least one cavity (47)

extends in the longitudinal direction (5) of the cutting blade (3), between at least two teeth of the plurality of cutting teeth (13).

10. The cutting blade (3) according to claim 8 or 9, wherein the at least one cavity (47) extends to an outer end (53) of the first surface (9).

1 1 . The cutting blade (3) according to claim 10, wherein the at least one cavity (47) extends to an outer end (53) of at least one tooth of the plurality of cutting teeth (13).

12. The cutting blade (3) according to any of the preceding claims, wherein the cutting blade (3) comprises at least one through hole (43) in the region of the at least one depression (25).

13. The cutting blade (3) according to any of the preceding claims, wherein a depth of the at least one depression (25) is less than or equal to 0.5 mm from the first surface (9).

14. The cutting blade (3) according to any of the preceding claims, wherein the cutting blade (3) comprises a third surface (19) opposite to the first surface (9), and wherein the third surface (19) is provided with at least one third depression, so as to reduce friction between the third surface (19) and a fourth surface (24) of the cutting apparatus (1 ), and wherein the at least one third depression has been produced by laser machining.

15. The cutting blade (3) according to any of the preceding claims, wherein the cutting apparatus (1 ) is a power-driven hand-held cutting apparatus.

16. A cutting apparatus (1 ) comprising a cutting blade (3) according to any of the

preceding claims, wherein the cutting apparatus (1 ) is a power-driven hand-held cutting apparatus comprising a second cutting blade (15), wherein the second surface (1 1 ) is a surface of the second cutting blade (15).

17. The cutting apparatus (1 ) according to claim 16, wherein the second cutting blade (15) is a cutting blade according to any of the claims 1 -14.

18. The cutting apparatus (1 ) according to claim 17, wherein the at least one depression (25) of the first surface (9) and at least one second depression of the second surface (1 1 ) each comprises at least one trace, and wherein the traces extend at least partially substantially in the transverse direction (7) of the cutting blades (3, 15), such that a direction of the trace of the first surface (9) is different from a direction of the trace of the second surface (1 1 ) when the surfaces (9, 1 1 ) abut against each other when arranged in the cutting apparatus (1 ).

19. A method of manufacturing a cutting blade for a cutting apparatus, wherein the

cutting blade extends in a longitudinal and a transverse direction and comprises a first surface arranged to be in sliding contact with a second surface of the cutting apparatus, and wherein the first surface comprises a sliding portion and a cutting portion, the cutting portion comprising a plurality of cutting teeth arranged at spaced intervals,

wherein the method comprises;

producing (101 ) at least one depression in the first surface in at least the sliding portion using a laser machining apparatus, so as to reduce friction between the first and second surfaces.

20. The method of manufacturing a cutting blade for a cutting apparatus according to claim 19, wherein the method further comprises:

producing (102) at least one protrusion in the first surface, adjacent to the at least one depression, using the laser machining apparatus.

21 . The method of manufacturing a cutting blade for a cutting apparatus according to claim 19 or 20, wherein the method further comprises:

producing (103) the at least one depression in the form of a number of dents, using the laser machining apparatus.

22. The method of manufacturing a cutting blade for a cutting apparatus according to claim 19 or 20, wherein the method further comprises:

providing (104) a relative motion between the first surface and a laser head of the laser machining apparatus to thereby produce a depression in the form of a trace in the first surface when using the laser machining apparatus.

23. The method of manufacturing a cutting blade for a cutting apparatus according to claim 22, wherein the trace extends to an outer end of the first surface.

24. The method of manufacturing a cutting blade for a cutting apparatus according to claim 19 or 20, wherein the method further comprises:

producing (105) the at least one depression in the form of an at least one cavity, using the laser machining apparatus.

25. The method of manufacturing a cutting blade for a cutting apparatus according to any of the claims 19-24, wherein the method further comprises:

producing (106) at least one through hole in the region of the at least one depression.

26. The method of manufacturing a cutting blade for a cutting apparatus according to any of the claims 19-25, wherein the method further comprises:

laser cutting (107) the cutting blade from sheet metal, using the laser machining apparatus.