Method of manufacturing blade of cutting device

Abstract

A method (200) of manufacturing a blade (130, 140, 310, 320, 440, 450) includes laser cutting the blade (130, 140, 310, 320, 440, 450) from a metal sheet having a first hardness such that an edge (150, 160, 330, 460, 470) of the blade (130, 140, 310, 320, 440, 450) after laser cutting has a local hardness greater than the first hardness. The method (200) is characterized in that the laser cutting of the blade (130, 140, 310, 320, 440, 450) is followed by a heat treatment process such that the edge (150, 160, 330, 460, 470) of the blade (130, 140, 310, 320, 440, 450) has a second hardness. The second hardness is less than the local hardness.

Description

Technical Field

[0001] The present disclosure relates to a cutting device having two blades, and more particularly, to a method for manufacturing the blades of the cutting device. Background Art

[0002] Cutting devices, such as hedge trimmers, pruning shears, garden shears, loppers and scissors, can be used for various gardening operations, such as cutting, pruning, trimming and shearing of hedges, shrubs, plants and the like. The cutting device may include two blades that can move relative to each other. One of the two blades may be a cutting blade and the other blade may be an anvil blade. Furthermore, the blade may be made by laser cutting of sheet metal. Laser cutting may automatically result in some heat treatment of the blade near the edge of the blade and may result in hardening of the edge of the blade.

[0003] During the operation of the cutting device, when the cutting blade can move relative to the anvil blade, the anvil blade may cause the wear of the cutting blade, so that the worn edge of the cutting blade is worn away, and the performance of the cutting device can be gradually reduced. In order to effectively prevent the wear of the cutting blade, a grinding process can be carried out after the laser cutting to grind away the hardened edge of the cutting blade and / or the anvil blade. Then, the hardness of the edge of the cutting blade and / or the anvil blade can be partially reduced and numerically closer to the initial hardness of the metal sheet (softer than the hardness automatically generated during the laser cutting). However, the grinding process of the cutting blade and / or the anvil blade may be a time-consuming, cumbersome and costly process. Therefore, it may be generally desirable to have a kind of improved, easy and cost-effective method to manufacture the anvil blade or two blades of the cutting device, it is desirable that the life of the blade of the cutting device can be increased.

[0004] An example of a cutting device is provided in European patent application EP 4,026,420 A1 (hereinafter referred to as the '420 reference). The '420 reference provides a cutting device having a first blade and a second blade. The first blade is manufactured by thermal cutting (particularly laser cutting), while the second blade is manufactured by a shearing process. The first blade and the second blade after laser cutting and shearing process, respectively, can be further processed, such as sharpening, flattening, trimming, leveling, cleaning / rustproofing, etc. Summary of the invention

[0005] In view of the above, an object of the present invention is to solve or at least reduce the above disadvantages. This object is at least partly achieved by a method for manufacturing a cutting blade.

[0006] According to one aspect of the invention, a method for manufacturing a blade comprises laser cutting a blade from a metal sheet having a first hardness, so that the edge of the blade has a local hardness greater than the first hardness after laser cutting. The method is characterized in that the laser cutting of the blade is followed by a heat treatment process so that the edge of the blade has a second hardness. The second hardness is less than the local hardness.

[0007] Thus, the present disclosure provides an improved method for manufacturing a blade. The method can ensure a longer blade life due to a lower probability of wear of the blade. The method can provide a blade with a softer edge, or an edge with a hardness substantially similar to the hardness of the metal sheet from which the blade is made. The method can be fast, reliable, cost-effective and energy-efficient.

[0008] The first hardness according to the present invention may represent the hardness of the metal sheet from which the blade may be manufactured. Furthermore, the local hardness according to the present invention may represent the hardness of a local area near the laser cutting edge of the blade. Furthermore, the second hardness according to the present invention may represent the hardness of a local area near the edge of the blade after a heat treatment process.

[0009] According to an exemplary embodiment of the present invention, the laser beam in laser cutting may be generated by a suitable laser light source, for example, a carbon dioxide laser, a neodymium aluminum garnet laser, and a fiber laser.

[0010] According to an exemplary embodiment of the present invention, the temperature of the heat treatment process is less than 400°C, preferably 375°C. The heat treatment process can be used to change the microstructure of the blade, which can be made of a metal sheet. The heat treatment process can increase the service life of the blade. The heat treatment process of the blade at 375°C can significantly reduce the hardness of the blade, in particular reduce the hardness of the blade edge increased due to laser cutting. The heat treatment process can reduce the hardness of the blade edge from a local hardness to a second hardness. In other words, the heat treatment process can heat up the blade and soften the hardness of the blade (specifically the blade edge).

[0011] According to an exemplary embodiment of the present invention, the heat treatment process may be limited to the localized area where the hardness is increased after laser cutting or the area around it. According to an exemplary embodiment of the present invention, the heat treatment process may be performed on the complete blade.

[0012] According to an exemplary embodiment of the present invention, the duration of the heat treatment process is at least 1.5 hours, preferably 3 hours. Preferably, the blade can be heated at a temperature of 375°C for 3 hours, so that the blade edge may soften, and the hardness of the blade edge increased by laser cutting will be greatly reduced thereafter.

[0013] According to an exemplary embodiment of the present invention, the local hardness is in the range of 58 to 61 HRC. In a specific embodiment, it is 59.5 HRC. In this regard, in an embodiment, the second hardness can be expected to be in the range of 53 to 55 HRC. Thus, in a specific embodiment, the second hardness is 54.4 HRC.

[0014] The heat treatment process can significantly reduce the hardness of the blade edge from the local hardness to a second hardness.The heat treatment process can eliminate the need to grind the hardened edge of the blade, which can otherwise be a tedious and costly process.

[0015] According to another aspect of the invention, a cutting device uses two blades that move relative to each other. At least one of the two blades can be manufactured via laser cutting and a subsequent heat treatment process, such that the temperature of the heat treatment process is less than 400°C, preferably 375°C, and the duration of the heat treatment process is at least 1.5 hours, preferably 3 hours. The cutting device with two blades can be used in gardening, kitchens, art and crafts, among other applications.

[0016] According to an exemplary embodiment of the present invention, two blades of the cutting device are coupled to each other using a plurality of fasteners, an upper bracket and a lower bracket. In addition, a plurality of spacers can be provided between the two blades, and / or between the blades and the upper bracket, and / or between the blades and the lower bracket. According to the arrangement of the plurality of spacers, the plurality of spacers can prevent friction between the blades, and / or between the blades and the upper bracket, and / or between the blades and the lower bracket.

[0017] According to an exemplary embodiment of the present invention, the two blades of the cutting device may be manufactured by laser cutting and a subsequent heat treatment process to obtain a durable performance of the cutting device.

[0018] According to an exemplary embodiment of the present invention, one blade is fixed and the other blade is movable. The movable blade can be a cutting blade. In addition, the fixed blade can be a cutting board or anvil blade and can provide a flat surface to support cutting, such as cutting hedges, shrubs, etc. by the cutting blade. The cutting blade can be close to the flat surface of the cutting board or anvil blade.

[0019] According to an exemplary embodiment of the invention, at least one movable blade performs a pivoting motion. At least one blade may be movable to perform anvil cuts or bypass cuts. For example, the cutting device may be a pruning shear having a pair of pivoting handles and may have a single movable cutting blade that is closed against a flat surface to perform anvil cuts.

[0020] According to an exemplary embodiment of the present invention, at least one movable blade performs linear motion. At least one movable blade can perform reciprocating or oscillating motion to allow the cutting device to perform cutting of hedges, bushes, plants, etc. At least one blade can be moved using the power of a motor, engine or any other propulsion device.

[0021] According to an exemplary embodiment of the present invention, the cutting device is a hedge trimmer. A hedge trimmer is a gardening tool that can be used to trim (cut, prune) a hedge or individual shrubs (bushes). A hedge trimmer can be a portable and handheld cutting device. A hedge trimmer can be powered by a drive source such as a motor or an engine.

[0022] According to an exemplary embodiment of the present invention, the cutting device is a scissors. The scissors may support bypass cutting, so that the two cutting blades of the scissors can be moved to an overlapping position while performing a cutting action. The scissors may be manual scissors or electric scissors. It is obvious to a person skilled in the art that there may be other possible embodiments with a cutting device similar to scissors, for example with pruning shears or large shears, in particular gardening shears.

[0023] Before discussing the invention with the aid of the accompanying drawings, the invention is briefly discussed in general. A method for manufacturing at least one blade of a cutting device is developed, the device employing two blades. The at least one blade can be manufactured by laser cutting the at least one blade from a metal sheet. After laser cutting, the at least one blade can be heat treated in a heating furnace at a temperature of up to 375°C for a duration of 1.5 to 3 hours. The heat treatment is more of a heating process and not a hardening process at all. The heating process may result in a softening of the hardness of the at least one blade (particularly any local hardness caused by the laser cutting).

[0024] The method according to the invention can ensure a lasting blade performance with a good cutting edge. The method according to the invention can allow avoiding significant wear processes of at least one blade manufactured by the method according to the invention without expensive operations of scraping the laser cut edge.

[0025] According to an exemplary embodiment of the present invention, the method for manufacturing at least one blade of a cutting device may include heat treatment after laser cutting. The hardness difference of at least one blade manufactured by the method of the present invention may not be greater than 3 HRC.

[0026] Other features and aspects of the present invention will become apparent from the following description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be described in more detail with reference to the accompanying drawings, in which:

[0028] Figure 1 shows a perspective view of a hedge trimmer according to an exemplary embodiment of the present disclosure;

[0029] Figure 2 shows a perspective view of a blade of a hedge trimmer according to an exemplary embodiment of the present disclosure;

[0030] Figure 3 A flow chart showing a method for manufacturing a blade of a cutting device according to an exemplary embodiment of the present disclosure;

[0031] Figure 4 shows an exploded view of an elongated cutter of a hedge trimmer according to an exemplary embodiment of the present disclosure;

[0032] Figure 5 shows an assembly view of an elongated cutter of a hedge trimmer according to an exemplary embodiment of the present disclosure;

[0033] Figure 6 A perspective view showing a pair of scissors according to an exemplary embodiment of the present disclosure; and

[0034] Figure 7 A perspective view of a pole pruner according to an exemplary embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0035] The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the present invention incorporating one or more aspects of the present invention are shown. However, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will be thorough and complete and the scope of the present invention will be fully conveyed to those skilled in the art. For example, one or more aspects of the present invention may be used in other embodiments and even other types of structures and / or methods. In the accompanying drawings, like reference numerals refer to like elements.

[0036] Certain terms used herein are for convenience only and should not be considered as limiting the present invention. For example, "upper", "lower", "front", "back", "side", "longitudinal", "lateral", "transverse", "upward", "downward", "forward", "backward", "sideways", "left", "right", "horizontal", "vertical", "upward", "inside", "outside", "inward", "outward", "top", "bottom", "higher", "above", "below", "center", "in the middle", "middle", "between", "end", "adjacent", "near", "near", "far", "distant", "radial", "circumferential", etc. only describe the configurations shown in the drawings. In fact, components can be oriented in any direction, and therefore, unless otherwise specified, the terms should be understood to include such variations.

[0037] Figure 1 A perspective view of a cutting device 100 is shown. Figure 1 The cutting device 100 in the embodiment is shown as a hedge trimmer. The hedge trimmer includes a body 110. The body 110 includes a handle 112 that allows a user to hold the hedge trimmer. The handle 112 also includes a power switch 114 to selectively start the hedge trimmer. In addition, the body 110 accommodates a drive system (not shown) including a drive source and a transmission mechanism. The drive system is configured to drive an elongated cutter 120. The drive system is mechanically engaged with the elongated cutter 120. The elongated cutter 120 includes two blades 130, 140. In other words, the cutting device 100 employs two blades 130, 140 that move relative to each other. The two blades 130, 140 have the same geometry. The blade 130 will be described in detail below, and the same description will also apply to the blade 140.

[0038] Figure 2 A perspective view of a blade 130 is shown. The blade 130 is manufactured by laser cutting a metal sheet having a first hardness. The blade 130 formed by laser cutting also undergoes a heat treatment process. The blade 130 has a first end 132 and a second end 134. The first end 132 is arranged opposite to the second end 134. The first end 132 is a mounting end or a drive end configured to be mechanically engaged to a drive system. The second end 134 is a free end disposed away from the body 110 of the hedge trimmer. The first end 132 and the second end 134 are separated by an elongated portion 136. The elongated portion 136 extends along the length of the blade 130. The elongated portion 136 is defined along a longitudinal axis XX'. The elongated portion 136 includes an edge 150 and an edge 160, such that the edge 150 is disposed on one side of the longitudinal axis XX' and the edge 160 is disposed on an opposite side of the longitudinal axis XX'.

[0039] In addition, edge 150 is different from edge 160 in geometry and properties. Edge 150 is the anvil edge of blade 130, and edge 160 is the cutting edge of blade 130. The cutting edge performs a cutting action, while the anvil edge does not perform a cutting action. The anvil edge provides a surface to support or hold the cutting element when the cutting edge performs a cutting action. Edge 150 has a larger size than edge 160. Edges 150, 160 each have a plurality of teeth.

[0040] Furthermore, laser cutting the metal sheet to produce the blade 130 results in local hardening of the edges 150, 160 of the blade 130 after laser cutting such that the local hardness is greater than the first hardness. The edge 160 is ground such that any residual local hardness may no longer exist at the edge 160.

[0041] Figure 3 A flow chart of a method 200 for manufacturing at least one of two blades 130, 140 is shown. By adopting the method 200, at least one of the two blades 130, 140 is manufactured using a metal sheet. For understanding the present invention, it is assumed that by adopting the method 200, the blade 130 is manufactured using a metal sheet. The method 200 for manufacturing the blade 130 includes a step 210. Step 210 includes laser cutting the blade 130 from a metal sheet having a first hardness, so that the edges 150, 160 of the blade 130 have a local hardness greater than the first hardness after laser cutting. The method 200 for manufacturing the blade 130 also includes a step 220. Step 220 includes performing a heat treatment process after laser cutting the blade 130, so that the edges 150, 160 of the blade 130 have a second hardness. The second hardness is less than the local hardness caused by the initial laser cutting. The temperature of the heat treatment process is less than 400°C, preferably 375°C. In addition, the duration of the heat treatment process is at least 1.5 hours, preferably 3 hours. Furthermore, for this exemplary embodiment, the local hardness after laser cutting is 59.5 HRC, and the secondary hardness after the heat treatment process is 54.4 HRC.

[0042] Figure 4 An exploded view of the elongated cutter 120 is shown. The elongated cutter 120 includes two blades 130, 140. The blades 130 and 140 include a first end 132, which is a mounting end or a drive end configured to be mechanically engaged to a drive system. In addition, the blades 130 and 140 include a second end 134. During assembly of the elongated cutter 120, the blade 130 is located above the blade 140. During assembly of the elongated cutter 120, the blade 140 is rotated 180° relative to the blade 130 so that each edge 160 of the blade 130 is located between two consecutive edges 150 of the blade 140. In addition, each edge 150 of the blade 130 is located between two consecutive edges 160 of the blade 140.

[0043] In addition, the blade 130 and the blade 140 each include an elongated portion 136. The elongated portion 136 of each of the blades 130 and 140 includes a plurality of holes 135 to allow the blades 130 and 140 to be coupled using a plurality of fastener groups 170 (including screws, washers and nuts), an upper bracket 172 and a lower bracket 174. The upper bracket 172 and the lower bracket 174 mechanically couple the two blades 130, 140 in a removable manner using the plurality of fastener groups 170. In addition, the second end 134 of the blade 130 is covered by a side bracket 176 using one of the plurality of fastener groups 170.

[0044] Figure 5 An assembled view of the elongated cutter 120 of the hedge trimmer is shown such that the blade 130 is located above the blade 140. Furthermore, the blade 140 is rotated 180° relative to the blade 130 such that each edge 160 of the blade 130 is between two consecutive edges 150 of the blade 140. Furthermore, each edge 150 of the blade 130 is located between two consecutive edges 160 of the blade 140. In such an arrangement of the elongated cutter 120, the two blades 130, 140 move relative to each other and at least one of the two blades 130, 140 performs a linear motion, or a reciprocating motion, or an oscillating motion.

[0045] Furthermore, in another embodiment, one of the two blades 130, 140 is fixed and the other blade 130, 140 is movable, such that at least one movable blade 130, 140 performs linear motion.

[0046] Figure 6 A perspective view of another cutting device 100 is shown. Figure 6 The cutting device 100 in the embodiment is shown as a pair of scissors in a closed state. The scissors include two blades 310, 320. In other words, the cutting device 100 employs two blades 310, 320 that move relative to each other. The blade 310 has a first edge 330 and the blade 320 has a second edge (not shown). The two blades 310, 320 are coupled along a pivot point 360 using a coupling 350. In addition, the scissors include grips 312, 322 to grip the two blades 310, 320, respectively.

[0047] In another embodiment, one of the two blades 310 , 320 is fixed and the other blade 310 , 320 is movable such that at least one movable blade 310 , 320 performs a pivotal movement along the pivot point 360 .

[0048] In addition, by adopting the method 200, at least one of the two blades 310, 320 is manufactured using a metal sheet. For understanding the present invention, it is assumed that by adopting the method 200, the blade 310 is manufactured using a metal sheet. The method 200 for manufacturing the blade 310 includes step 210. Step 210 includes laser cutting the blade 310 from a metal sheet having a first hardness, so that the edge 330 of the blade 310 has a local hardness greater than the first hardness after laser cutting. The method 200 for manufacturing the blade 310 also includes step 220. Step 220 includes performing a heat treatment process after laser cutting the blade 310, so that the edge 330 of the blade 310 has a second hardness. The second hardness is less than the local hardness generated by the initial laser cutting. The temperature of the heat treatment process is less than 400°C, preferably 375°C. In addition, the heat treatment process lasts at least 1.5 hours, preferably 3 hours. In addition, for this exemplary embodiment, the local hardness after laser cutting is 59.5 HRC, and the second hardness after the heat treatment process is 54.4HRC.

[0049] Figure 7 A perspective view of a further cutting device 100 is shown. Figure 7 The cutting device 100 in the embodiment is shown as a tree lopping shears. The tree lopping shears include a longitudinal member 410 having a first end 420 and a second end 430. The tree lopping shears include two blades 440, 450 coupled to the longitudinal member 410 toward the first end 420. In addition, the tree lopping shears include a handle 432 coupled to the longitudinal member 410 toward the second end 430, such that movement of the handle 432 away from and toward the second end 430 achieves movement of the two blades 440, 450. When the handle 432 is away from the second end 430, the two blades 440, 450 are away from each other, and when the handle 432 is toward the second end 430, the two blades 440, 450 are close to each other. In other words, the cutting device 100 employs two blades 440, 450 that move relative to each other. In addition, the two blades 440, 450 include edges 460, 470, respectively.

[0050] In another embodiment, one of the two blades 440, 450 is fixed and the other blade 440, 450 is movable such that at least one movable blade 440, 450 performs a pivoting movement.

[0051] In addition, by adopting the method 200, at least one of the two blades 440, 450 is manufactured using a metal sheet. For the purpose of understanding the present invention, it is assumed that by adopting the method 200, the blade 440 is manufactured using a metal sheet. The method 200 for manufacturing the blade 440 includes step 210. Step 210 includes laser cutting the blade 440 from a metal sheet having a first hardness, so that the edge 460 of the blade 440 has a local hardness greater than the first hardness after laser cutting. The method 200 for manufacturing the blade 440 further includes step 220. Step 220 includes performing a heat treatment process after laser cutting the blade 440, so that the edge 460 of the blade 440 has a second hardness. The second hardness is less than the local hardness generated by the initial laser cutting. The temperature of the heat treatment process is less than 400°C, preferably 375°C. In addition, the heat treatment process lasts at least 1.5 hours, preferably 3 hours. In addition, for this exemplary embodiment, the local hardness after laser cutting is 59.5 HRC, and the second hardness after the heat treatment process is 54.4 HRC.

[0052] In the drawings and specification, exemplary embodiments and examples of the invention have been disclosed, and although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limiting the scope of the invention set forth in the following claims.

[0053] Components List

[0054] 100 cutting devices

[0055] 110 body

[0056] 112 handle

[0057] 114 Power switch

[0058] 120 Slim Cutters

[0059] 130 blade

[0060] 132 First End

[0061] 134 Second End

[0062] 135 holes

[0063] 136 Slender part

[0064] 140 blade

[0065] 150 Edge

[0066] 160 Edge

[0067] 170 Fastener Set

[0068] 172 upper bracket

[0069] 174 lower bracket

[0070] 176 side bracket

[0071] 200 Methods

[0072] 210 steps

[0073] 220 steps

[0074] 310 blade

[0075] 312 grip

[0076] 320 blade

[0077] 322 grip

[0078] 330 First Edge

[0079] 350 connector

[0080] 360 pivot point

[0081] 410 longitudinal member

[0082] 420 First End

[0083] 430 Second End

[0084] 432 handle

[0085] 440 blade

[0086] 450 blade

[0087] 460 Edge

[0088] 470 Edge

[0089] X-X' longitudinal axis

Claims

1. A method (200) for manufacturing a blade (130, 140, 310, 320, 440, 450), comprising: laser cutting the blade (130, 140, 310, 320, 440, 450) from a metal sheet having a first hardness, wherein an edge (150, 160, 330, 460, 470) of the blade (130, 140, 310, 320, 440, 450) has a local hardness greater than the first hardness after laser cutting, The laser cutting of the blade (130, 140, 310, 320, 440, 450) is followed by a heat treatment process such that the edge (150, 160, 330, 460, 470) of the blade (130, 140, 310, 320, 440, 450) has a second hardness, Features: the second hardness is less than the local hardness, And the heat treatment is more of a heating process than a hardening process, wherein the blade is heat treated up to 400°C, preferably 375°C, And wherein, the heat treatment process lasts for at least 1.5 hours, preferably, 3 hours.

2. The method (200) according to claim 1, wherein: The local hardness is in the range of 58 to 61 HRC.

3. The method (200) according to claim 2, wherein: The second hardness is in the range of 53 to 55 HRC.

4. A cutting device (100) comprising two blades (130, 140, 310, 320, 440, 450) that move relative to each other, wherein at least one of the blades (130, 140, 310, 320, 440, 450) has a plurality of laser cutting anvil edges (150) that provide a surface to support or hold a cutting element while a plurality of cutting edges (160) of the other blade (130, 140, 310, 320, 440, 450) perform a cutting action, in, The anvil edge (150) has a larger dimension than the cutting edge (160), It is characterized in that The overall hardness difference of the at least one blade (130, 140, 310, 320, 440, 450) is no greater than 3 HRC.

5. The cutting device (100) according to claim 4, wherein: One blade (130, 140, 310, 320, 440, 450) is fixed, while the other blade (130, 140, 310, 320, 440, 450) is movable.

6. The cutting device (100) according to claim 5, wherein: At least one movable blade (310, 320, 440, 450) performs pivotal movement.

7. The cutting device (100) according to claim 5, wherein: At least one movable blade (130, 140) performs linear motion.

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