Crankshaft assembly for handheld power tool

Abstract

A crankshaft assembly for a handheld power tool. The crankshaft assembly includes: a first engagement member defining a first opening; a second engagement member defining a second opening; a crankshaft coupled to the first engagement member and the second engagement member and configured to rotate about a rotation axis; and at least one crank arm coupled to the crankshaft for driving one or both of the first engagement member and the second engagement member. The crankshaft assembly further includes a first sliding member disposed in the first opening and a second sliding member disposed in the second opening and in contact with the first sliding member.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 698,615, filed September 25, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to crankshaft mechanisms and handheld power tools having crankshaft mechanisms, such as hedge trimmers. Background Technology

[0004] Typically, handheld power tools, such as hedge trimmers and chainsaws, use crankshafts to convert the rotational motion of a small engine into translational motion for operation. These mechanisms allow handheld power tools to efficiently cut through objects or perform other desired tasks. Translational motion can generate undesirable vibrations and noise. Therefore, there is a need in the art for improved crankshaft mechanisms. In particular, crankshafts that reduce vibration and noise would be advantageous. Summary of the Invention

[0005] The aspects and advantages of this disclosure will be set forth in part in the description which follows, or may be apparent from the description, or may be learned by practice of the art.

[0006] According to one embodiment, a crankshaft assembly for a handheld power tool is provided. The crankshaft assembly includes: a first engaging member defining a first opening; a second engaging member defining a second opening; a crankshaft coupled to the first and second engaging members and configured to rotate about a rotation axis; and at least one crank arm coupled to the crankshaft for driving one or both of the first and second engaging members. The crankshaft assembly further includes: a first sliding member disposed in the first opening; and a second sliding member disposed in the second opening and in contact with the first sliding member.

[0007] According to another embodiment, a handheld power tool is provided. The handheld power tool includes: a first reciprocating element extending between a first end and a second end opposite to the first end; and a second reciprocating element extending between the first end and the second end. The first end of the first reciprocating element includes a first engagement member defining a first opening, and the first end of the second reciprocating element includes a second engagement member defining a second opening. The handheld power tool also includes a power unit and a crankshaft assembly that connects the power unit to the first end of the first reciprocating element and the first end of the second reciprocating element. The crankshaft assembly includes: a crankshaft configured to rotate about a rotation axis; at least one crank arm connected to the crankshaft to drive one or both of the first and second reciprocating elements; a first sliding member disposed in the first opening; and a second sliding member disposed in the second opening and in contact with the first sliding member.

[0008] These and other features, aspects, and advantages of the present disclosure will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the technology and serve to explain the principles of the technology. BRIEF DESCRIPTION OF DRAWINGS

[0009] The complete and enabling disclosure of the present application, including the best mode thereof, to one of ordinary skill in the art, is set forth in the specification, which references the drawings, in which:

[0010] Figure 1 is a cross-sectional view of a hedge trimmer according to an embodiment of the present disclosure;

[0011] Figure 2 is a perspective view of a crankshaft assembly according to an embodiment of the present disclosure; and

[0012] Figure 3 is a detailed perspective view of the crankshaft assembly of Figure 2 according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0013] Reference will now be made in detail to embodiments of the present disclosure, one or more examples of which are illustrated in the drawings. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, each example is provided in one embodiment of the present technology, but the application is not limited to one embodiment. In fact, many modifications and variations will be apparent to those skilled in the art upon reading this document, which demonstrates the principles of the present technology. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield still a further embodiment. Thus, it is intended that the present disclosure cover such modifications and variations as come within the scope of the appended claims and their equivalents. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to indicate like or similar elements. As used herein, the term “if’ can be construed to mean “when” or “upon” or “in response to the

[0014] As used herein, the terms "first," "second," and "third" can be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. The terms "coupled," "fixed," "attached to" and like terms mean either a direct connection or an indirect connection via one or more intermediary devices or features unless otherwise stated herein. As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having" or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of features is not necessarily limited only to those features but can include other features not expressly listed or inherent to such process, method, article, or apparatus. Further, unless expressly stated to the contrary, "or" refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present); A is false (or not present) and B is true (or present); and both A and B are true (or present).

[0015] Approximating language, such as "approximately," "substantially," "generally," or "about," with reference to an angle or direction indicates that the angle or direction is within 10 degrees of the stated angle or direction. For example, "generally vertical" includes directions within 10 degrees of vertical in any direction, such as clockwise or counterclockwise.

[0016] As used herein, the term "monolithic," "unitary," or "one-piece" with respect to a structure means that the structure is integrally formed from a continuous material or set of materials, without seams, connecting joints, or the like. Monolithic unitary structures described herein can be formed by additive manufacturing to have the described structure, or alternatively by a casting process or the like.

[0017] The benefits, other advantages, and solutions to problems have been described herein with regard to specific embodiments. However, the benefits, advantages, solutions to problems and any feature(s) that can cause any benefit, advantage, or solution to occur or to become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims.

[0018] Generally, a hand-held power tool includes a crankshaft for converting rotational motion from an automated force device, such as an electric motor, to translational motion. This translational motion can create secondary vibrations and undesirable noise within the hand-held power tool. The translational motion can also create increased stress on components of the crankshaft. Accordingly, including one or more sliding members in the crankshaft assembly of a hand-held power tool can reduce such vibrations, noise, and stress.

[0019] Reference is now made to the drawings, Figure 1 A cross-sectional view of a hedge trimmer 100 according to an embodiment of the present disclosure is shown. The hedge trimmer 100 generally includes at least one reciprocating cutting tool. For example, the hedge trimmer 100 can include a first reciprocating element such as a first blade 102 and a second reciprocating element such as a second blade 104. The first blade 102 and the second blade 104 each include "teeth" that will cause the blades to cut into material, such as branches of a hedge, as the tool reciprocates. For example, the first blade 102 can be a first cutting blade that includes a plurality of first teeth, and the second blade 104 can be a second cutting blade that includes a plurality of second teeth. In other example embodiments, only one of the first blade 102 and the second blade 104 is configured to reciprocate. For example, one of the first blade 102 and the second blade 104 can remain stationary, and the other of the first blade 102 and the second blade 104 reciprocates so as to cause the blades to cut into material.

[0020] The hedge trimmer 100 can also include a housing 106. The first blade 102 and the second blade 104 can extend from the housing 106. Further, the first blade 102 and the second blade 104 of the hedge trimmer 100 can be coupled to a spine 120 that extends from the housing 106 for supporting the first blade 102 and the second blade 104. The hedge trimmer 100 can include a handle 108.

[0021] As Figure 1 The hedge trimmer 100 can also include a power device 125, such as an electric motor or a gas-powered engine, that drives a crankshaft assembly 130, as shown in FIG. 1. For example, the power device 125 can be disposed within the housing 106. As will be discussed in further detail below, the crankshaft assembly 130 can be engaged with the first blade 102 and the second blade 104 such that rotation of a crankshaft of the crankshaft assembly 130 causes the first blade 102 and the second blade 104 to reciprocate. Although the crankshaft assembly 130 is discussed in connection with the hedge trimmer 100, it should be understood that the crankshaft assembly 130 can be used with other power tools, such as a reciprocating saw, a jigsaw (or multi-purpose tool), a reciprocating snipper, a compressor, a dual action sander, and a jigsaw.

[0022] The power plant 125 can be powered by a rechargeable energy source, such as the battery 116, a fuel source, such as gasoline, or the like. In the depicted example embodiment, the hedge trimmer 100 includes an actuator 118. The actuator 118 is disposed proximate the handle 108. When depressed, the actuator 118 can engage the power plant 125 to move the first blade 102 and the second blade 104. As the actuator 118 is further depressed, the speed of the power plant can increase from a zero speed to a maximum speed. In this regard, the actuator 118 can variably affect the speed of the power plant between a stop speed that occurs when the actuator 118 is not depressed and a maximum speed that occurs when the actuator 118 is fully depressed.

[0023] Figure 2 A perspective view of a crankshaft assembly 130 is shown in accordance with an embodiment of the present disclosure. Figure 1 A perspective view of a crankshaft assembly 130 is shown in accordance with an embodiment of the present disclosure.

[0024] The first blade 102 and the second blade 104 extend from a first end 201 toward a second end 202 opposite the first end 201. For example, the second blade 104 and the first end 201 of the first blade 102 can be coupled to the crankshaft assembly 130 and at least partially disposed within the housing 106 Figure 1 The crankshaft assembly 130 includes a crankshaft 205 and a gear 210. The gear 210 can be coupled to the power plant 125 and the crankshaft 205 to transfer rotational motion from the power plant 125 to the crankshaft 205 such that the gear 210 and the crankshaft 205 rotate about an axis of rotation 215. For example, when the crankshaft 205 rotates about the axis of rotation 215 in a first direction A, the first blade 102 and the second blade 104 reciprocate in a second direction B that is perpendicular to the axis of rotation 215. Thus, rotational motion of the crankshaft 205 about the axis of rotation 215 in the first direction A is converted to linear motion of the first blade 102 and the second blade 104 in the second direction B.

[0025] Figure 3 A detailed perspective view of a crankshaft assembly 130 is shown in accordance with an embodiment of the present disclosure. Figure 2 A detailed perspective view of a crankshaft assembly 130 is shown in accordance with an embodiment of the present disclosure. Figure 3 The crankshaft assembly 130 is shown with the gear 210 removed.

[0026] As Figure 3As shown in FIG. 1, the first end 201 of the first blade 102 includes a first engagement member 305 defining a first opening 310, and the first end 201 of the second blade 104 includes a second engagement member 315 defining a second opening 320. In at least one example embodiment, the first opening 310 and the second opening 320 can have a square or rectangular shape. In other example embodiments, the first opening 310 and the second opening 320 can have a circular or polygonal shape. The first engagement member 305 can be integral with the first blade 102, and the second engagement member 315 can be integral with the second blade 104. In other example embodiments, the first blade 102 can be coupled to and extend from the first engagement member 305, and the second blade 104 can be coupled to and extend from the second engagement member 315.

[0027] The first opening 310 of the first blade 102 and the second opening 320 of the second blade 104 are configured to receive at least a portion of the crankshaft assembly 130. For example, the crankshaft 205 can be disposed within the first opening 310 and the second opening 320. Accordingly, the crankshaft 205 is configured to drive one or both of the first blade 102 and the second blade 104.

[0028] Further, the crankshaft assembly 130 can include at least one crank arm 325 coupled to and extending from the crankshaft 205. The at least one crank arm 325 can be configured to drive one or both of the first blade 102 and the second blade 104 upon rotation of the crankshaft 205. As Figure 3 As shown in FIG. 1, the at least one crank arm 325 can be disposed in the first opening 310 for driving the first blade 102. Additionally or alternatively, the at least one crank arm 325 can include a first crank arm disposed in the first opening 310 for driving the first blade 102 and a second crank arm disposed in the second opening 320 for driving the second blade 104.

[0029] In at least one example embodiment, the crankshaft assembly 130 includes one or more sliding members for reducing vibration and high contact stress. For example, the crankshaft assembly 130 can include a first sliding member 330 disposed in the first opening 310 and a second sliding member 335 disposed in the second opening 320. Further, the first sliding member 330 can be in contact with at least a portion of the second sliding member 335. Further, as Figure 3As shown in FIG. 3, the first sliding member 330 can surround the at least one crank arm 325. Thus, the at least one crank arm 325, the first sliding member 330, and the second sliding member 335 convert the rotational motion of the crankshaft into the reciprocating motion of the first blade 102 and / or the second blade 104. The first sliding member 330 and the second sliding member 335 can have a generally square, rectangular, or any other polygonal shape. The generally square or rectangular shape provides reduced vibrations and lowers the contact stress with the inner surfaces of the first opening 310 and the second opening 320. In other example embodiments, the first sliding member 330 and the second sliding member 335 can have a circular or oval shape. In still other example embodiments, a plurality of needle bearings can be provided in one or both of the first sliding member 330 and the second sliding member 335 to reduce the sliding friction with the inner surfaces of the first opening 310 and the second opening 320.

[0030] The first sliding member 330 and the second sliding member 335 can be formed of a resilient damping material that is configured to absorb vibrations and reduce stress applied on the components of the crankshaft assembly 130. For example, the first sliding member 330 and the second sliding member 335 are configured to contact the inner surfaces of the first opening 310 and the second opening 320 during operation of the crankshaft assembly 130, rather than contacting the at least one crank arm 325 of the crankshaft 205. Further, the first sliding member 330 and the second sliding member 335 are configured to slide against each other during rotation of the crankshaft 205. Thus, when the crankshaft 205 rotates and the first blade 102 and the second blade 104 are reciprocated by the at least one crank arm 325, the first sliding member 330 and the second sliding member 335 move within the first opening 310 and the second opening 320, respectively. Accordingly, the first sliding member 330 reduces stress applied on the inner surface of the first engagement member 305 defining the first opening 310, and the second sliding member 335 reduces stress applied on the inner surface of the second engagement member 315 defining the second opening 320.

[0031] Further aspects of the present disclosure are provided by one or more of the following embodiments:

[0032] A crankshaft assembly for a hand-held power tool, the crankshaft assembly comprising: a first engagement member defining a first opening; a second engagement member defining a second opening; a crankshaft coupled to the first engagement member and the second engagement member and configured to rotate about an axis of rotation; at least one crank arm coupled to the crankshaft for driving one or both of the first engagement member and the second engagement member; a first sliding member disposed in the first opening; and a second sliding member disposed in the second opening and in contact with the first sliding member.

[0033] The crankshaft assembly of any one or more embodiments, wherein the at least one crank arm is disposed in the first opening, and the first sliding member at least partially surrounds the at least one crank arm.

[0034] The crankshaft assembly of any one or more embodiments, wherein the at least one crank arm, the first sliding member, and the second sliding member are configured to convert rotational motion of the crankshaft about the rotational axis to linear motion of one or both of the first engagement member and the second engagement member.

[0035] The crankshaft assembly of any one or more embodiments, wherein the at least one crank arm includes a first crank arm disposed in the first opening and a second crank arm disposed in the second opening.

[0036] The crankshaft assembly of any one or more embodiments, wherein the first opening and the second opening define a rectangular shape.

[0037] The crankshaft assembly of any one or more embodiments, wherein: the first sliding member is configured to reduce stress applied to an inner surface of the first engagement member defining the first opening; and the second sliding member is configured to reduce stress applied to an inner surface of the second engagement member defining the second opening.

[0038] The crankshaft assembly of any one or more embodiments, further comprising a power device coupled to the crankshaft for driving rotation of the crankshaft about the rotational axis.

[0039] The crankshaft assembly of any one or more embodiments, further comprising a first reciprocating element extending from the first engagement member and a second reciprocating element extending from the second engagement member.

[0040] The crankshaft assembly of any one or more embodiments, wherein the first engagement member is integral with the first reciprocating element, and the second engagement member is integral with the second reciprocating element.

[0041] The crankshaft assembly of any one or more embodiments, wherein: the first reciprocating element includes a first cutting blade having a plurality of first teeth; and the second reciprocating element includes a second cutting blade having a plurality of second teeth.

[0042] A hand-held power tool comprising: a first reciprocating element extending between a first end and a second end opposite the first end, the first end including a first engagement member defining a first opening; a second reciprocating element extending between the first end and the second end, the first end including a second engagement member defining a second opening; a power device; and a crankshaft assembly coupling the power device to the first end of the first reciprocating element and the first end of the second reciprocating element, the crankshaft assembly comprising: a crankshaft configured to rotate about a rotational axis; at least one crank arm coupled to the crankshaft for driving one or both of the first reciprocating element and the second reciprocating element, a first sliding member disposed in the first opening, and a second sliding member disposed in the second opening and in contact with the first sliding member.

[0043] The hand-held power tool of any one or more embodiments, wherein the at least one crank arm is disposed in the first opening, and the first sliding member at least partially surrounds the at least one crank arm.

[0044] The hand-held power tool of any one or more embodiments, wherein: the power device drives the crankshaft to rotate about the rotational axis; and the at least one crank arm, the first sliding member, and the second sliding member are configured to convert rotational motion of the crankshaft about the rotational axis to linear motion of one or both of the first reciprocating element and the second reciprocating element.

[0045] The hand-held power tool of any one or more embodiments, wherein the at least one crank arm comprises a first crank arm disposed in the first opening and a second crank arm disposed in the second opening.

[0046] The hand-held power tool of any one or more embodiments, wherein the first opening and the second opening define a rectangular shape.

[0047] The hand-held power tool of any one or more embodiments, wherein: the first sliding member is configured to reduce stress applied to an inner surface of the first engagement member defining the first opening; and the second sliding member is configured to reduce stress applied to an inner surface of the second engagement member defining the second opening.

[0048] The hand-held power tool of any one or more embodiments, wherein: the first reciprocating element includes a first cutting blade having a plurality of first teeth; and the second reciprocating element includes a second cutting blade having a plurality of second teeth.

[0049] The hand-held power tool of any one or more embodiments, wherein the hand-held power tool comprises a hedge trimmer.

[0050] The hand-held power tool of any one or more embodiments, wherein the hand-held power tool comprises a reciprocating saw, an oscillating saw, a reciprocating shear, a compressor, a dual action sander, or a jigsaw.

[0051] The hand-held power tool of any one or more embodiments, wherein the first engagement member is integral with the first reciprocating element and the second engagement member is integral with the second reciprocating element.

[0052] This written description uses examples to disclose the application, including the best mode, and also to enable any person skilled in the art to practice the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the present disclosure is defined by the claims, and can include other examples that occur to those skilled in the art. Such other examples are intended to fall within the scope of the claims if they include structural equivalents to elements of the literal language of the claims, or if they include insubstantial non-structural variations.

Claims

1. A crankshaft assembly for a handheld power tool, characterized in that, The crankshaft assembly includes: A first engaging member that defines the first opening; The second engaging member that defines the second opening; A crankshaft, which is connected to the first and second coupling members and is configured to rotate about an axis of rotation; At least one crank arm, said at least one crank arm being coupled to said crankshaft, for driving one or both of the first engagement member and the second engagement member; A first sliding member disposed in the first opening; and A second sliding member is disposed in the second opening and in contact with the first sliding member.

2. The crankshaft assembly according to claim 1, characterized in that, The at least one crank arm is disposed in the first opening, and the first sliding member at least partially surrounds the at least one crank arm.

3. The crankshaft assembly according to claim 1, characterized in that, The at least one crank arm, the first sliding member, and the second sliding member are configured to convert the rotational motion of the crankshaft about the axis of rotation into linear motion of one or both of the first and second engaging members.

4. The crankshaft assembly according to claim 1, characterized in that, The at least one crank arm includes a first crank arm disposed in the first opening and a second crank arm disposed in the second opening.

5. The crankshaft assembly according to claim 1, characterized in that, The first opening and the second opening define a rectangular shape.

6. The crankshaft assembly according to claim 1, characterized in that: The first sliding member is configured to reduce the stress applied to the inner surface of the first engaging member defining the first opening; and The second sliding member is configured to reduce the stress applied to the inner surface of the second engaging member that defines the second opening.

7. The crankshaft assembly according to claim 1, characterized in that, The crankshaft assembly also includes a power unit connected to the crankshaft for driving the crankshaft to rotate about the axis of rotation.

8. The crankshaft assembly according to claim 1, characterized in that, The crankshaft assembly further includes a first reciprocating element extending from the first engagement member and a second reciprocating element extending from the second engagement member.

9. The crankshaft assembly according to claim 8, characterized in that, The first engaging member is integral with the first reciprocating element, and the second engaging member is integral with the second reciprocating element.

10. The crankshaft assembly according to claim 8, characterized in that: The first reciprocating element includes a first cutting blade, the first cutting blade including a plurality of first teeth; and The second reciprocating element includes a second cutting blade, which includes a plurality of second teeth.

11. A handheld power tool, characterized in that, The handheld power tool includes: A first reciprocating element extends between a first end and a second end opposite to the first end, the first end including a first engagement member defining a first opening; A second reciprocating element extends between the first end and the second end, the first end including a second engaging member defining a second opening; Power unit; and A crankshaft assembly, which connects the power unit to a first end of the first reciprocating element and a first end of the second reciprocating element, the crankshaft assembly comprising: A crankshaft configured to rotate about an axis of rotation. At least one crank arm, connected to the crankshaft, is provided for driving one or both of the first reciprocating element and the second reciprocating element. The first sliding member disposed in the first opening, and A second sliding member is disposed in the second opening and in contact with the first sliding member.

12. The handheld power tool according to claim 11, characterized in that, The at least one crank arm is disposed in the first opening, and the first sliding member at least partially surrounds the at least one crank arm.

13. The handheld power tool according to claim 11, characterized in that: The power unit drives the crankshaft to rotate about the axis of rotation; and The at least one crank arm, the first sliding member, and the second sliding member are configured to convert the rotational motion of the crankshaft about the axis of rotation into linear motion of one or both of the first reciprocating element and the second reciprocating element.

14. The handheld power tool according to claim 11, characterized in that, The at least one crank arm includes a first crank arm disposed in the first opening and a second crank arm disposed in the second opening.

15. The handheld power tool according to claim 11, characterized in that, The first opening and the second opening define a rectangular shape.

16. The handheld power tool according to claim 11, characterized in that: The first sliding member is configured to reduce the stress applied to the inner surface of the first engaging member defining the first opening; and The second sliding member is configured to reduce the stress applied to the inner surface of the second engaging member that defines the second opening.

17. The handheld power tool according to claim 11, characterized in that: The first reciprocating element includes a first cutting blade, the first cutting blade including a plurality of first teeth; and The second reciprocating element includes a second cutting blade, which includes a plurality of second teeth.

18. The handheld power tool according to claim 11, characterized in that, The handheld power tool includes a hedge trimmer.

19. The handheld power tool according to claim 11, characterized in that, The handheld power tools include reciprocating saws, vibrating saws, reciprocating shears, compressors, double-action sanders, or jigsaws.

20. The handheld power tool according to claim 11, characterized in that, The first engaging member is integral with the first reciprocating element, and the second engaging member is integral with the second reciprocating element.

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