Handheld bandsaw

Abstract

The present invention relates to a handheld bandsaw, comprising a substantially planar frame, a main handle extending upwards and outwards from the frame, and an auxiliary handle located substantially in front of the main handle, wherein the main handle comprises a first gripping part, the first gripping part extending along a second plane parallel to a cutting plane, and the auxiliary handle comprises a first end and a second gripping part, the first end being located directly in front of the first gripping part and intersecting the second plane, and the second gripping part extending from the first end towards the cutting plane. The bandsaw of the present invention has an improved auxiliary handle design and is suitable for operating requirements of different processing positions.

Description

[0001] Hilti Aktiengesellschaft

[0002] Principality of Liechtenstein

[0003] Handheld bandsaw

[0004] TECHNICAL FIELD

[0005] The present invention relates to a cutting tool, in particular to a handheld bandsaw.

[0006] BACKGROUND ART

[0007] Handheld bandsaws currently on the market are generally held by a main handle and an auxiliary handle simultaneously to complete a processing operation. In existing handheld bandsaws, the main handle is usually arranged on upper and rear parts of a saw wheel housing frame; for example, the main handle is arranged at a position rearward of a cut-in region where the bandsaw blade cuts into a material being cut, extending forwards and upwards from one side of the saw wheel housing frame, and descending at a top end side (front end side). In existing handheld bandsaws, three forms of auxiliary handle are common, e.g. a spherical handle arranged in front of the main handle, disclosed in CN102186615A; a C-shaped handle, disclosed in CN115592201A; and an auxiliary handle part arranged on a side face of a battery pack mounting part 27, disclosed in CN117620307A.

[0008] When using a handheld bandsaw, the main handle is gripped to control a trigger to activate the bandsaw, while the auxiliary handle (e.g. spherical handle) is gripped with lifting pressure, cooperating with the main handle to complete a cutting operation. When operating a handheld bandsaw to perform work, it is necessary to simultaneously consider the requirements of cutting upwards, downwards and directly ahead, i.e. three positions. However, although existing handheld bandsaws can meet the basic requirement of a user cutting downwards, they are unable to provide effective support when cutting upwards and directly ahead, so are quite physically demanding. For example, when the auxiliary handle is a C-shaped handle or a spherical handle arranged in front of the main handle, the user's right hand grips the main handle while his left hand grips the auxiliary handle; thus, the user's left and right hands are offset from the cutting plane of the bandsaw blade, making accurate manipulation difficult. In particular, when processing a workpiece in a forward or upward direction, the left hand gripping the auxiliary handle might also interfere with the user's line of sight, affecting the convenience and accuracy of operation. As for an auxiliary handle part arranged on a side face of a battery pack mounting part 27, this easily causes deflection of the bandsaw blade cutting plane when the bandsaw is processing a workpiece in a downward direction, and the overall structure of the bandsaw is not compact enough.

[0009] SUMMARY OF THE INVENTION

[0010] The technical problem to be solved by the present invention is to provide a handheld bandsaw which has an improved auxiliary handle design and is suitable for operating requirements of different processing positions.

[0011] The present invention provides a handheld bandsaw, comprising a substantially planar frame in which are accommodated a driving wheel and a driven wheel, wherein the driving wheel and the driven wheel are meshed with an annular saw blade, and the frame defines a first plane; the frame is further provided with an opening for receiving a workpiece, a tilted part of the annular saw blade being exposed in the opening; the tilted part defines a cutting plane, and the bandsaw further comprises a main handle extending upwards and outwards from the frame and an auxiliary handle located in front of the main handle, wherein the main handle comprises a first gripping part, the first gripping part extending along a second plane parallel to the cutting plane; the auxiliary handle comprises a first end and a second gripping part, the first end being located in front of the first gripping part and intersecting the second plane, and the second gripping part extending from the first end towards the cutting plane. The present invention provides a novel secondary handle design, which can simultaneously meet the operating requirements of a user for using a bandsaw at different processing positions. When the handheld bandsaw needs to process a workpiece in a downward direction, the user can grip the first gripping part with one hand while the other hand grips the first end of the auxiliary handle, such that the exposed part of the saw blade of the bandsaw can cut the workpiece substantially perpendicularly in a downward direction. When the handheld bandsaw needs to process a workpiece in a forward or upward direction, the user can grip the first gripping part with one hand while the other hand grips the second gripping part of the auxiliary handle; the obliquely arranged second gripping part can provide more effective support during forward or upward processing by the bandsaw. The user can select different gripping points quickly according to actual needs, and does not need to perform any mechanical adjustment of the auxiliary handle itself to meet operating requirements for different positions.

[0012] The auxiliary handle further comprises a second end connecting the second gripping part to the frame. This improves the rigidity of the auxiliary handle.

[0013] The second end is connected to the frame at a position close to the opening. Based on ergonomic considerations, the second end is designed to be as close to a cutting point as possible, so as to provide a better supporting force while satisfying safety regulations.

[0014] The second gripping part extends from the first end towards the second end in a curve. Thus, the design of the auxiliary handle is more ergonomic, and easy for a user to grip. Preferably, the second gripping part is substantially arc-shaped, and a line connecting two ends of the arc shape of the second gripping part forms an angle a with the second plane, the angle being such that 15° < a < 90°. Such a second gripping part is simple to process, while the bandsaw has a compact body which can meet the requirements of operation in confined spaces.

[0015] The centre of the first end is within the second plane. Thus, the centre of the first end and the first gripping part are both within the second plane; when simultaneously gripping the main handle and the auxiliary handle to process a workpiece in a downward direction, the user can simultaneously press the bandsaw downwards more effectively, so as to increase the cutting efficiency.

[0016] The first end of the auxiliary handle is connected to the main handle by a connecting part. Thus, the main handle and the auxiliary handle form a single piece, and the handle assembly is structurally simple while also having good strength and durability.

[0017] The handheld bandsaw of the present invention provides an improved auxiliary handle design. The user can select different gripping points quickly according to actual needs, and does not need to perform any mechanical adjustment of the auxiliary handle mechanism itself to meet operating requirements for different positions. At the same time, the bandsaw has a compact structural design, and is suitable for various application scenarios.

[0018] BRIEF DESCRIPTION OF THE DRAWINGS

[0019] A better understanding of the embodiments mentioned can be gained from the following detailed description with reference to the drawings. It is emphasized that the various components are not necessarily drawn to scale. In fact, dimensions can be enlarged or reduced at will for the purpose of clear discussion. In the drawings, identical reference labels denote identical elements.

[0020] Fig. 1 is a main view of the handheld bandsaw of the present invention. Fig. 2 is a side view of the handheld bandsaw of the present invention.

[0021] DETAILED DESCRIPTION OF THE INVENTION

[0022] The handheld bandsaw of the present invention is described below with reference to Figs. 1 and 2. The following description is merely exemplary, and does not limit the disclosed content of the present application or the applications or uses of the present invention. The terms “front”, “rear”, “above...”, “below...”, “left” and “right” in the present invention are used throughout this specification to define various components of the handheld bandsaw of the present invention when arranged in an orientation in which it is to be used.

[0023] Referring to Figs. 1 and 2, as an example, a bandsaw 1 of the present invention is a rechargeable handheld bandsaw. The bandsaw 1 comprises a substantially planar, roughly C-shaped frame 10. The substantially planar frame 10 defines a first plane P1. The frame 10 has a first end 11 and a second end 12 opposite each other; the first end

[0024] 11 and the second end 12 are connected by a transverse member 13, and an opening 14 for receiving a workpiece is provided between the first end 11 and the second end

[0025] 12 at a side opposite the transverse member. The first end 11 accommodates a driving wheel having a first rotation shaft; the second end 12 accommodates a driven wheel having a second rotation shaft. The driving wheel is connected to a motor (not shown) by means of a transmission apparatus, the motor being received in a motor housing 16 projecting from an upper surface of the first end 11. The driven wheel is connected, by means of a tensioning assembly (not shown) mounted on the frame 10, to a journal arranged on a bottom face of the second end 12 of the frame 10, and the driven wheel is thus able to rotate under the driving action of the driving wheel.

[0026] A bandsaw blade 15 of a certain width is set up between the driving wheel and the driven wheel, the bandsaw blade being flexible in a plate thickness direction. The bandsaw blade 15 forms a closed loop and surrounds the driving wheel and the driven wheel. The bandsaw blade 15 mostly extends parallel to an axial direction of the first rotation shaft, but is twisted by a guide component (not shown) only in a region of the opening, and thus has a tilted part exposed in the opening 14. The exposed tilted part of the bandsaw blade defines a cutting plane CP; the cutting plane CP is different from the first plane P1 of the substantially planar frame, and forms a certain angle with the first plane P1. The bandsaw blade 15 rotating in a loop pushes against a workpiece to be cut (not shown) by means of the tilted part exposed in the opening region, so as to cut the workpiece.

[0027] An upper part of the frame 10 is provided with a handle assembly for a user to grip. The handle assembly comprises a main handle 20 gripped by the user with one hand, and an auxiliary handle 30 gripped with the other hand. The main handle 20 is arranged substantially at a position rearward of a cutting region in the opening 14, and extends forwards and upwards in a hill shape from a side where the motor housing 16 is installed on the frame 10, forming a first gripping part 21 for the user to grip with one hand. The direction in which the main handle 20 extends upwards from the frame 10 defines a second plane P2, the second plane P2 being substantially parallel to the cutting plane CP. According to a schematic embodiment of the present invention, preferably, a handle axis H-H of the first gripping part 21 is inclined in an upward-tilted direction from a rear side towards a front side. There is a downward incline from a top end 22, forming a front end 23 which extends until it is joined to a handle base 24. The handle base 24 is fixed and joined to an upper surface of the frame 10 by a screw. A switch 25 is provided on a lower surface side of the first gripping part 21 , the switch being operated by being pressed by a fingertip of a hand gripping the main handle 20. When the user operates the switch 24, the motor starts, causing the bandsaw blade 15 to rotate in a loop. The user gripping the main handle 20 applies a pressing force (a cutting force applied by the bandsaw blade 15 to the material being cut) in a direction substantially perpendicular to the handle axis H-H. This is so that a cut-in direction, in which the bandsaw blade 15 cuts into the workpiece to be cut, is the same as the direction in which the pressing force of the user's hand acts. This allows the pressing force of the user's hand gripping the main handle 20 to be effectively applied to the cutting region, to perform a cutting job quickly with a relaxed posture while lightening the burden applied to the user's wrist.

[0028] The auxiliary handle 30 is arranged in front of the main handle 20. The auxiliary handle 30 comprises a first end 31 and a second gripping part 32, the first end being located directly in front of the first gripping part 21 and intersecting the second plane, and the second gripping part extending from the first end 31 towards the cutting plane. Preferably, the first end 31 is perpendicular to the second plane P2, and the centre of the first end 31 lies on the second plane P2. The first end 31 is connected by a connecting part 26 to the front end 23 of the main handle 20. Preferably, the connecting part 26 also extends within the second plane P2; that is to say, the centre of the first end 31 , the connecting part 26, the front end 23 and the first gripping part 21 are coplanar, and the second plane P2 is parallel to the cutting plane CP.

[0029] According to a schematic embodiment of the present invention, the first end 31 is constructed as a spherical handle, and the centre of the first end 31 is within the second plane. The first end 31 constructed as a spherical handle enables the hands gripping the first end 31 and the first gripping part 21 to simultaneously press the bandsaw downwards more effectively when the bandsaw 1 is processing a workpiece in a downward direction, so as to increase the cutting efficiency as well as user-friendliness. The second gripping part 32 extends from one side of the first end 31 towards the cutting plane CP. It will be understood that the second gripping part 32 may have various extension shapes and angles. The shape of the second gripping part 32 and the angle of extension thereof depend on the structural design of the bandsaw and the ergonomics applied to the bandsaw. For example, the second gripping part 32 may be a substantially cylindrical handle extending in a direction substantially perpendicular to the second plane P2, with the first end 31 transitioning to the second gripping part 32 in an arc shape, and a cross-sectional diameter of the second gripping part preferably being 15 mm - 35 mm, so as to make gripping feel more comfortable for the user. Alternatively, the second gripping part 32 is an L-shaped, C-shaped or D-shaped handle. According to a preferred embodiment of the present invention, the second gripping part 32 extends from the first end 31 towards a second end 33 in a curve, in particular in an arc shape. A line connecting two ends of the arc shape of the second gripping part forms an angle a with the second plane, the range of the angle preferably being 15° < a < 90°. Thus, the design of the auxiliary handle is more ergonomic, while the bandsaw has a compact body which can meet the requirements of operation in confined spaces.

[0030] Preferably, the auxiliary handle 30 further comprises the second end 33, which connects the second gripping part 32 to the frame 10. This improves the rigidity of the auxiliary handle. The second end 33 is connected to the frame at a position close to the opening 14. Based on ergonomic considerations, the second end 33 is designed to be as close to a cutting point as possible, so as to provide a better supporting force while satisfying safety regulations.

[0031] A sensor for detecting a user gripping state is mounted on the main handle 20 and / or the auxiliary handle 30. For example, a first sensor is deployed on the first gripping part 21 , and can detect a first hand of the user on the first gripping part 21 . Touch sensors (e.g. capacitive touch sensors, inductive touch sensors) are separately deployed on the second gripping part 33 and the first end 31. The touch sensors are configured to detect a second hand of the user positioned on a second handle. The bandsaw comprises a controller, which can control motor operation and monitor an activation state of the first sensor and the touch sensors. When the touch sensor of either the second gripping part 33 or the first end 31 is in an activated state and the first sensor is also in an activated state, the controller drives the motor. When the first sensor is in an activated state, but neither touch sensor of the second gripping part 33 and the first end 31 detects that the user's other hand is gripping the auxiliary handle 30, the controller prohibits motor operation.

[0032] The present invention provides a design for a novel auxiliary handle 30, combining a spherical handle located in front of a main handle 20 and a secondary handle located laterally with respect to a frame in the prior art to form a one-piece auxiliary handle. With a simple and compact structure, it can simultaneously meet the operating requirements of a user for using a bandsaw at different processing positions. When the handheld bandsaw 1 needs to process a workpiece in a downward direction, the user can grip the first gripping part 21 of the main handle 20 with one hand while the other hand grips the first end 31 of the auxiliary handle 30. Since the first end 31 and the first gripping part 21 are both within the second plane P2 parallel to the cutting plane CP, the tilted part of the bandsaw blade 15 exposed in the opening 14 can cut the workpiece substantially perpendicularly in a downward direction when the user presses the main handle 20 and the auxiliary handle 30 downwards, thus increasing the cutting efficiency and the precision of the cutting job. When the handheld bandsaw 1 needs to process a workpiece in a forward or upward direction, the user can grip the first gripping part 21 of the main handle 20 with one hand while the other hand grips the second gripping part 32 of the auxiliary handle 30. The obliquely arranged second gripping part can provide more effective support during forward or upward processing by the bandsaw. The user can select different gripping points quickly according to actual needs, and does not need to perform any mechanical adjustment of the auxiliary handle itself to meet operating requirements for different positions.

[0033] As stated above, although exemplary embodiments of the present invention have been explained herein with reference to the drawings, the present invention is not limited to the specific embodiments above, and could have many other embodiments. The scope of the present invention shall be defined by the claims and their equivalent meaning.

Claims

PATENT CLAIMS1. Handheld bandsaw, comprising a substantially planar frame in which are accommodated a driving wheel and a driven wheel, wherein the driving wheel and the driven wheel are meshed with an annular saw blade, and the frame defines a first plane; the frame is further provided with an opening for receiving a workpiece, a tilted part of the annular saw blade being exposed in the opening; the tilted part defines a cutting plane, and the bandsaw further comprises a main handle extending upwards and outwards from the frame and an auxiliary handle located in front of the main handle, wherein the main handle comprises a first gripping part, the first gripping part extending along a second plane parallel to the cutting plane, characterized in that the auxiliary handle comprises a first end and a second gripping part, the first end being located in front of the first gripping part and intersecting the second plane, and the second gripping part extending from the first end towards the cutting plane.

2. Handheld bandsaw according to Claim 1 , characterized in that the auxiliary handle further comprises a second end connecting the second gripping part to the frame.

3. Handheld bandsaw according to Claim 2, characterized in that the second end is connected to the frame at a position close to the opening.

4. Handheld bandsaw according to Claim 3, characterized in that the second gripping part extends from the first end towards the second end in a curve.

5. Handheld bandsaw according to Claim 4, characterized in that the second gripping part is substantially arc-shaped, and a line connecting two ends of the arc shape of the second gripping part forms an angle a with the second plane, the angle being such that 15° < a < 90°.

6. Handheld bandsaw according to any one of Claims 1 - 5, characterized in that the centre of the first end is within the second plane.

7. Handheld bandsaw according to Claim 6, characterized in that the first end is connected to the main handle by a connecting part.

8. Handheld bandsaw according to any one of Claims 1 - 7, characterized in that a sensor for detecting a user gripping state is provided on the main handle and / or the auxiliary handle.

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