Battery-powered electric band saw

Abstract

To eliminate a difference in cutting load due to a difference in battery weight without making complicated adjustments when replacing a battery with one of a different capacity. [Solution] The battery-powered electric band saw 1 comprises a holding base 1A that holds the workpiece W to be cut, and a saw blade support 1B that is rotatably attached to a hinge portion 1C provided on one end of the holding base 1A and supports a saw blade 20. The saw blade support 1B has a battery mounting portion 24 that allows batteries of different capacities to be mounted at a position away from the hinge portion 1C, and the hinge portion 1C is provided with an adjustment mechanism 40 that adjusts the cutting load by adjusting the spring force that acts as a resistance to the weight of the saw blade support 1B, and the adjustment mechanism 40 is provided with a switching portion (switching lever) 43 that switches the spring force depending on the capacity of the battery mounted in the battery mounting portion 24.

Description

[Technical Field]

[0001] The present invention relates to a battery-powered electric band saw. [Background technology]

[0002] Conventionally, electric band saws have included a holder that holds the workpiece to be cut, such as a pipe, and a saw blade support that is rotatably attached to a hinge at one end of the holder, supporting the saw blade.The saw blade is operated by an electric mechanism provided in the saw blade support, and the weight of the saw blade support is used as the cutting load to cut the workpiece held on the holder (see Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Microfilm of Jikkai No. 59-46628 Summary of the Invention [Problem to be solved by the invention]

[0004] The conventional electric band saws described above generally operate the saw blade by rotating an electric motor mounted on the saw blade support using power supplied from a commercial power source. However, to enable use in situations where connecting to a commercial power source is difficult, models have been developed that incorporate a battery in the saw blade support and operate the saw blade using power supplied from this battery.

[0005] In the case of such battery-powered band saws, it is preferable to mount the battery on the side of the saw blade support, considering the wiring to the electric motor. In this case, the weight of the battery affects the cutting load. Furthermore, in consideration of factors such as continuous operating time, it is preferable for battery-powered electric band saws to be able to choose between a large-capacity battery and a small-capacity battery. However, allowing such a choice creates the problem of differences in cutting load due to the difference in battery weight between the large-capacity battery and the small-capacity battery.

[0006] In addition, in a battery-powered electric band saw, the weight of the battery can be effectively added to the cutting load, thereby reducing the weight of the saw blade support, and the lighter body improves convenience when used as a portable device. To effectively add the weight of the battery to the cutting load, it is preferable to install the battery in a position away from the hinge. However, if batteries with different capacities are installed interchangeably in a single position away from the hinge, differences in battery weight will result in large differences in cutting load.

[0007] One solution to this problem is to use a cutting load adjustment mechanism provided in the hinge section to adjust the cutting load according to the capacity of the installed battery. However, readjusting the cutting load every time the battery is replaced is extremely cumbersome. Furthermore, if proper adjustment is not possible each time, an inappropriate cutting load can lead to poor cut finish, poor workability during cutting, and in some cases, adverse effects such as wear on the saw blade.

[0008] The present invention was proposed to address these problems. Specifically, in a battery-powered electric band saw in which batteries of different capacities can be selected and attached to a fixed position on the saw blade support, the object of the present invention is to eliminate the difference in cutting load due to differences in battery weight when replacing a battery with a different capacity without having to perform complicated adjustments. [Means for solving the problem]

[0009] In order to solve such problems, the present invention has the following configuration. A battery-powered electric band saw comprising a holding base for holding the material to be cut, and a saw blade support that is rotatably attached to a hinge provided on one end of the holding base and supports a saw blade; the saw blade is operated by power from a battery mounted on the saw blade support, and the saw blade cuts the material to be cut held on the holding base using the weight of the saw blade support as the cutting load; the saw blade support has a battery mounting section that can mount batteries of different capacities at a position away from the hinge section, the hinge section has an adjustment mechanism that adjusts the cutting load by adjusting the spring force that acts as a resistance to the weight, and the adjustment mechanism has a switching section that switches the spring force depending on the capacity of the battery mounted on the battery mounting section. [Effects of the Invention]

[0010] According to the present invention, which has such characteristics, in a battery-powered electric band saw in which batteries of different capacities can be selected appropriately and attached to a fixed position on the saw blade support, when replacing a battery with one of a different capacity, the difference in cutting load due to differences in battery weight can be eliminated without having to make complicated adjustments. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a side view showing a battery-powered electric band saw according to an embodiment of the present invention. [Figure 2] FIG. 10 is an explanatory diagram (partial cross-sectional view) showing an adjustment mechanism in a hinge portion. [Figure 3] FIG. 4 is an explanatory diagram showing the lever operation of the switching lever. [Figure 4] FIG. 4 is an explanatory diagram showing the lever operation of the switching lever. [Figure 5] FIG. 10 is an explanatory diagram showing the results of adjusting the cutting load by switching the switching lever. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals in different drawings denote parts with the same functions, and duplicated descriptions in each drawing will be omitted as appropriate.

[0013] As shown in FIG. 1, a battery-powered electric band saw (hereinafter referred to as an electric band saw) 1 includes a holder 1A and a saw blade support 1B. The holder 1A includes a holding mechanism 10 that holds the workpiece W to be cut. The holding mechanism 10 may be, for example, a vise mechanism that can hold the pipe-shaped workpiece W in a fixed state. In the illustrated example, the mechanism includes a fixed plate 11 that is screwed to the holder 1A, a movable plate 12 that can be moved toward or away from the fixed plate 11, a screw shaft 14 with a knob 13 attached to its tip, and a fixed female screw portion 15 into which the screw shaft 14 is threaded. By rotating the knob 13 and moving the screw shaft 14 relative to the fixed female screw portion 15, the movable plate 12 slides, and the workpiece W is sandwiched and fixed between the fixed plate 11 and the movable plate 12.

[0014] The saw blade support 1B is rotatably attached to a hinge portion 1C provided on one end of the holder 1A, and movably supports the saw blade 20. A battery 30 is mounted on the saw blade support 1B, and the saw blade 20 is electrically driven by power supplied from the battery 30. The electric band saw 1 cuts the workpiece W held on the holder 1A with the saw blade 20, using the weight of the saw blade support 1B as the cutting load.

[0015] The aforementioned weight of the saw blade support 1B refers to the weight of the saw blade support 1B itself plus the weight of the battery 30 and all of the components mounted on the saw blade support 1B, such as the drive mechanism. The saw blade support 1B is equipped with the aforementioned drive mechanism, including the electric motor 21 and a drive circuit 22 that drives the electric motor 21.

[0016] In the electric band saw 1, a pipe-shaped workpiece W is fixed to the holding mechanism 10 of the holder 1A so that it is parallel to the hinge axis of the hinge portion 1C, and the saw blade support 1B is swung around the hinge axis of the hinge portion 1C to cut the pipe-shaped workpiece W with the saw blade 20, which is disposed approximately perpendicular to the longitudinal direction of the workpiece W. A handle portion 23 is provided on the saw blade support 1B, but the operator does not apply pressure to the cutting load with the hand holding the handle portion 23. As a result, the cutting load of the saw blade 20 is borne solely by the weight of the saw blade support 1B, and the workpiece W can be cut with a constant cutting load corresponding to the weight.

[0017] The saw blade support 1B is provided with a battery mounting portion 24 that can mount a battery 30 at a position away from the hinge portion 1C. The battery mounting portion 24 is provided at the movable end of the saw blade support 1B, so that the weight of the battery 30 is effectively added to the cutting load. This makes it possible to obtain a desired cutting load by adding the weight of the battery 30 even if the weight of the saw blade support 1B itself is reduced. Reducing the weight of the saw blade support 1B improves portability when the battery 30 is removed from the battery mounting portion 24 and the operator carries the electric band saw 1 by holding the handle portion 23.

[0018] Batteries 30 of different capacities (battery capacity) can be interchangeably attached to the battery attachment portion 24. The weight of the battery 30 varies depending on the capacity, with a large-capacity battery 30 being heavier than a small-capacity battery 30. For this reason, the weight of the saw blade support 1B will differ when a large-capacity battery 30 is attached to the battery attachment portion 24 and when a small-capacity battery 30 is attached to the battery attachment portion 24.

[0019] The hinge portion 1C is provided with an adjustment mechanism 40 as shown in Fig. 2. The adjustment mechanism 40 is provided to adjust the cutting load due to the weight of the saw blade support body 1B described above. The adjustment mechanism 40 adjusts the spring force of the torsion spring 41 that exerts resistance against the weight of the saw blade support body 1B, and includes a first adjustment mechanism 40A provided on an arm portion 41A on one side of the torsion spring 41, and a second adjustment mechanism 40B provided on an arm portion 41B on the other side of the torsion spring 41.

[0020] The first adjustment mechanism 40A adjusts the position of the tip of the arm 41A of the torsion spring 41 up and down as indicated by the arrow H1 in the figure by adjusting the adjustment screw 42, in which the tip of the arm 41A is inserted into a hole. This changes the position of the tip of the arm 41A up and down, thereby continuously changing the spring force of the torsion spring 41. Lowering the adjustment screw 42 delays the timing at which the resistance of the torsion spring 41 acts on the cutting motion (cutting angle) of the saw blade support body 1B, making the resistance against its own weight less effective and reducing the degree of adjustment to reduce the cutting load. On the other hand, raising the adjustment screw 42 advances the timing at which the resistance of the torsion spring 41 acts on the cutting motion (cutting angle) of the saw blade support body 1B, making the resistance against its own weight more effective and increasing the degree of adjustment to reduce the cutting load.

[0021] The second adjustment mechanism 40B is provided to eliminate the difference in cutting load due to the weight of the saw blade support 1B. When the winding angle of the torsion spring 41 around the hinge shaft 1C1 increases, the spring force acting as a resistance to the weight of the saw blade support 1B increases, and conversely, when the winding angle around the hinge shaft 1C1 decreases, the spring force acting as a resistance to the weight of the saw blade support 1B decreases.

[0022] Taking advantage of this, the second adjustment mechanism 40B is provided with a switching unit 43 that switches the spring force depending on the capacity of the battery 30 attached to the battery attachment part 24. As an example, the switching unit 43 can be configured with a switching lever 43L. The switching lever 43L has a mechanism that switches the position of the tip of the arm 41B of the torsion spring 41 up and down as indicated by the arrow H2 in the figure. When the tip position of the arm 41B is moved upward, the spring force increases, and the resistance to the weight of the saw blade support body 1B increases. When the tip position of the arm 41B is moved downward, the spring force decreases, and the resistance to the weight of the saw blade support body 1B decreases.

[0023] More specifically, the switching lever 43L can be switched between a first position 43A, which increases the spring force when a large-capacity battery is installed, and a second position 43B, which decreases the spring force when a small-capacity battery is installed. FIG. 3 shows the state in which the switching lever 43L is switched to the first position 43A. In this state, the arm 41B of the torsion spring 41 moves upward due to the difference in height between the first position 43A and the second position 43B. FIG. 4 shows the state in which the switching lever 43L is switched to the second position 43B. In this state, the arm 41B of the torsion spring 41 moves downward due to the difference in height between the first position 43A and the second position 43B.

[0024] The switching lever 43L can be switched between the first position 43A and the second position 43B with a single push or pull operation. The switching lever 43L is supported so as to be movable along the axial direction of the hinge portion 1C, and as shown in Fig. 3, by pulling the switching lever 43L along the arrow A, the first position 43A is moved to the position of the arm portion 41B of the torsion spring 41, and as shown in Fig. 4, by pushing the switching lever 43L along the arrow B, the second position 43B is moved to the position of the arm portion 41B of the torsion spring 41.

[0025] 5 shows an example of adjusting the cutting load using the second adjustment mechanism 40B. The dashed line P1 in the figure indicates the cutting load due to the weight when a large-capacity battery 30 is attached to the battery attachment section 24 (change in cutting load with respect to cutting angle). The dashed line P2 in the figure indicates the cutting load due to the weight when a small-capacity battery 30 is attached to the battery attachment section 24 (change in cutting load with respect to cutting angle). As shown in the figure, if no adjustment is made, the cutting load will be greater when a large-capacity battery 30 is attached compared to when a small-capacity battery 30 is attached.

[0026] In contrast, the dashed line Q1 and the dashed-dotted line Q2 in the figure show the difference in spring force caused by the second adjustment mechanism 40B, with the dashed line Q1 showing the spring force (change in spring force with respect to cutting angle) when the switching lever 43L is switched to the first position 43A, and the dashed-dotted line Q2 showing the spring force (change in spring force with respect to cutting angle) when the switching lever 43L is switched to the second position 43B. As shown in the figure, the spring force at the first position 43A is greater than the spring force at the second position 43B.

[0027] The solid line P in the figure indicates the cut load after adjustment. When a large-capacity battery 30 is attached to the battery attachment section 24, a large spring force acts on the cut load (dashed line P1) due to its own weight, and the cut load is adjusted as shown by the solid line P by switching the switching lever 43L to the first position 43A. When a small-capacity battery 30 is attached to the battery attachment section 24, a relatively small spring force acts on the cut load (chain dotted line P2), and the cut load is adjusted as shown by the solid line P by switching the switching lever 43L to the second position 43B. In this way, by switching the position of the switching lever 43L depending on the battery capacity, the cut load after adjustment is the same when a large-capacity battery 30 is attached and when a small-capacity battery 30 is attached.

[0028] As described above, the electric band saw 1 according to the embodiment of the present invention is provided with the second adjustment mechanism 40B, which allows for stepless adjustment of the cutting load using the first adjustment mechanism 40A, as well as stepwise adjustment of the cutting load according to the capacity of the installed battery 30. As a result, once the cutting load has been adjusted using the first adjustment mechanism 40A, even if the capacity of the replaced battery 30 differs, the difference in cutting load due to the battery capacity can be eliminated by simply switching the switch lever 43L with a single operation.

[0029] In other words, according to an embodiment of the present invention, in a battery-powered electric band saw 1 in which batteries 30 of different capacities can be appropriately selected and attached to a fixed position on the saw blade support 1B, when replacing a battery with one of a different capacity, the difference in cutting load due to differences in battery weight can be eliminated without having to make complicated adjustments.

[0030] Furthermore, according to an embodiment of the present invention, the battery mounting section 24 is located in a fixed position where batteries 30 with different capacities can be interchangeably mounted, and is located away from the hinge section 1C so that the battery weight can be effectively added to the cutting load. This allows the desired cutting load to be obtained even if the weight of the saw blade support 1B minus the weight of the battery is reduced, and the weight of the electric band saw 1 excluding the battery 30 can be reduced, improving portability.

[0031] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the specific configurations are not limited to these embodiments, and the present invention also includes design changes within the scope of the present invention. Furthermore, the above-described embodiments can be combined by utilizing each other's technologies as long as there are no particular contradictions or problems in their purposes, configurations, etc. [Explanation of symbols]

[0032] 1: Battery-powered electric band saw (electric band saw) 1A: Holding base 1B: Saw blade support 1C: Hinge part 1C1: Hinge shaft 10: Holding mechanism 11: Fixed plate 12: Movable plate 13: Knob 14: Screw shaft 15: Fixed female screw portion 20: Saw blade 21: Electric motor 22: Drive circuit 23: Handle 24: Battery mounting part 30: Battery 40: Adjustment mechanism 40A: First adjustment mechanism 40B: Second adjustment mechanism 41: Torsion spring 41A, 41B: Arms 42: Adjustment screw 43: Switching part 43L: Switching lever 43A: 1st position 43B: 2nd position W: Material to be cut

Claims

1. A battery-powered band saw includes a holder that holds a workpiece, and a saw blade support that is rotatably attached to a hinge provided at one end of the holder, and supports a saw blade. The saw blade is operated by power supplied from a battery mounted on the saw blade support, and the weight of the saw blade support is used as a cutting load to cut the workpiece held on the holder with the saw blade. the saw blade support includes a battery mounting portion in which the batteries of different capacities can be mounted at positions away from the hinge portion; The hinge portion is provided with an adjustment mechanism that adjusts the cutting load by adjusting a spring force that acts as a resistance force against the weight of the hinge portion, The battery-powered electric band saw is characterized in that the adjustment mechanism is provided with a switching unit that switches the spring force depending on the capacity of the battery attached to the battery attachment unit.

2. 2. The battery-powered electric band saw according to claim 1, wherein the switching portion is a switching lever that can be switched between a first position that increases the spring force when a large-capacity battery is installed and a second position that decreases the spring force when a small-capacity battery is installed.

3. 3. The battery-powered electric band saw according to claim 2, wherein the first position of the switching lever moves an arm of the torsion spring wound around the hinge portion upward, and the second position of the switching lever moves the arm of the torsion spring downward.

4. 4. The battery-powered electric band saw according to claim 2, wherein the switching lever can be switched between the first position and the second position by a single push-pull operation.

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