Impact tool

Abstract

To provide an impact tool that can suppress noise and damage on a hummer and the like occurring during actuation, and is excellent in actuation efficiency and energy saving.SOLUTION: An impact tool 10 comprises: a tool body 11 having a cylinder 12 in which a hammer 13 reciprocates; and an impact imparting tool 1 that transmits an impact force of the hammer 13 to a work-piece W. The impact imparting tool 1 comprises: an imparting tool body 20 including a base end part 23 which is inserted into the cylinder 12; and a coil spring 55 joined to the base end part 23. The hammer 13 collides with the coil spring 55, whereby the impact force is transmitted to the imparting tool body 20 via the coil spring 55, and when the impact force is generated, the coil spring 55 prevents the hammer 13 and the imparting tool body 20 from contacting each other.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an impact tool that applies impact to a workpiece by the action of a mechanism in which a hammer reciprocates. [Background technology]

[0002] Conventionally, there has been known an impact tool that applies an impact to a workpiece containing casting sand to vibrate the workpiece and remove the casting sand (see, for example, Patent Document 1). In such an impact tool, a hammer that reciprocates in a cylinder part by air drive repeatedly collides with the base end of a tip tool, and the impact is applied to the workpiece from the tip of the tip tool. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-175797 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the impact tool of the conventional configuration described above, the hammer repeatedly collides with the base end of the tip tool, generating noise during the collision. Therefore, there has been a demand for reducing this noise. In addition, there is a risk that the tip tool and the hammer may be damaged by the repeated collision.

[0005] There is also a demand for impact tools that are more efficient in operation and that save energy, etc. However, in the above-mentioned conventional configuration in which the hammer is reciprocated only by controlling the supply of compressed air to the cylinder, there is a limit to the efficiency and energy savings.

[0006] An object of the present invention is to provide an impact tool which is capable of suppressing noise generated during operation and damage to the hammer, etc., while at the same time improving operational efficiency and saving energy. [Means for solving the problem]

[0007] The present invention is an impact tool comprising: a tool body having a cylinder and a hammer that reciprocates within the cylinder; and an impact applicator attached to the tip of the cylinder and transmitting an impact force generated by the reciprocating motion of the hammer to a workpiece, the impact applicator having a tip that contacts the workpiece and a base end that is inserted into the cylinder, and comprising an applicator body that is arranged to be movable along the operating direction in which the hammer reciprocates; and a coil spring that is joined to the base end of the applicator body and expands and contracts within the cylinder within a range that allows elastic deformation in the operating direction, the impact tool being characterized in that when the hammer collides with the coil spring, an impact force is transmitted to the applicator body via the coil spring, and when the impact force is generated, the coil spring keeps the hammer and the applicator body out of contact with each other.

[0008] In this configuration, the impact generated by the hammer hitting the coil spring is transmitted to the impact applying tool body via the coil spring, and the hammer and the impact applying tool do not collide, which reduces the noise generated by the hammer hitting and also suppresses damage to the hammer and the impact applying tool.

[0009] Furthermore, the elasticity of the coil spring, which is contracted by the forward movement of the hammer, is utilized for the double action of the hammer, so that the speed of the double action is improved, and the number of times the hammer is reciprocated per unit time can be increased compared to the conventional case. In other words, the amount of energy transmitted to the workpiece per unit time can be increased without increasing the supply of the power source (compressed air, etc.) required for the reciprocating movement of the hammer. Therefore, the configuration of the present invention can significantly improve the efficiency of operation and energy saving.

[0010] In the impact tool of the present invention described above, it is proposed that the applicator body is composed of a long member whose longitudinal direction is the extension and contraction direction of the coil spring, and the tip end of the coil spring is arranged at the base end of the long member.

[0011] In this configuration, the impact force generated by the forward movement (collision) of the hammer can be stably transmitted to the impact applicator via the coil spring, and the elastic force generated by the expansion of the coil spring can be stably transmitted to the hammer. This allows the reciprocating movement of the hammer, the expansion and contraction of the coil spring, and the operation of the impact applicator to be carried out more smoothly, further improving the effects of the present invention described above.

[0012] Furthermore, there is proposed an impact application device comprising the above-mentioned impact tool of the present invention and a work holding portion for holding a workpiece, and characterized in that an impact force is applied to the workpiece by reciprocating the hammer of the impact tool with the tip of the impact application tool abutting against the workpiece held in the work holding portion.

[0013] In this configuration, the impact force can be repeatedly applied to the workpiece while achieving the above-mentioned operational effects of the impact tool, and therefore the operation of applying an impact force to a desired workpiece can be stably performed for a relatively long period of time while improving the efficiency and energy saving of the operation. Effect of the Invention

[0014] The impact tool of the present invention can reduce noise generated during operation and prevent damage to the hammer and the impact applicator body. Furthermore, the number of times the hammer reciprocates per unit time can be increased, significantly improving the efficiency of operation and energy saving. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is an explanatory diagram of an impact tool according to an embodiment. [Diagram 2] (A) is a side view of a first body portion of the applicator body, (B) is a side view of a second body portion of the applicator body, (C) is a partially cross-sectional side view of a nut member attached to the applicator body, and (D) is a side view of a first coil spring, a second coil spring, and a third coil spring attached to the applicator body. [Diagram 3] 10 is an explanatory diagram showing an operation mode of a hammer and an impact applying tool. FIG. [Figure 4] FIG. 2 is an explanatory diagram of a casting sand removal device according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The present invention is not limited to the following examples, and appropriate design changes are possible. For convenience, the examples are described by specifying the beginning and end, but the present invention is not limited thereto.

[0017] As shown in Fig. 1, the impact tool 10 of this embodiment includes a tool body 11 provided with a cylinder 12, and an impact applicator 1 attached to the tool body 11 by a chisel cap 15. The tool body 11 includes a hammer 13 fitted reciprocally into the inside of the cylinder 12, an air passage (not shown) connected to the inside of the cylinder 12, and a valve mechanism (not shown) for controlling the inflow and outflow of compressed air into the air passage. The hammer 13 is reciprocated inside the cylinder 12 by controlling the supply and discharge of compressed air from a compressed air supply source to the inside of the cylinder 12 via the valve mechanism and the air passage.

[0018] A chisel cap 15 is connected to the tip of the tool body 11, and the impact applying tool 1 is disposed inside the chisel cap 15 so as to be movable along the longitudinal direction of the cylinder 12 (the operating direction in which the hammer 13 reciprocates). Here, the impact applying tool 1 has its tip protruding forward from the chisel cap 15 and its rear end inserted inside the cylinder 12.

[0019] 2, the impact applicator 1 is composed of a long impact applicator body 20, two nuts 30, a first coil spring 40, a second coil spring 50, and a third coil spring 55. Here, the third coil spring 55 is related to the essential part of the present invention, and will be described in detail later.

[0020] The applicator body 20 includes a first body portion 21 shown in Fig. 2(A) and a second body portion 25 shown in Fig. 2(B). The first body portion 21 includes a base end portion 23 inserted into the inside of the cylinder 12 and a large-diameter sliding portion 22 connected to the base end portion 23. The second body portion 25 is a round bar-shaped portion connected to the sliding portion 22 of the first body portion 21.

[0021] 2(A), the sliding part 22 of the first body part 21 is disposed inside the chisel cap 15 so as to be slidable in the operating direction and so as not to be inserted inside the cylinder 12, and is provided with a screw hole part 27 into which a screw groove 26 provided around the second body part 25 screws. The first body part 21 and the second body part 25 are integrated by screwing the screw hole part 27 of the sliding part 22 into the screw groove 26 of the second body part 25, thereby forming the applicator body 20. In this manner, the applicator body 20 is configured as an elongated member disposed such that its longitudinal direction is aligned with the operating direction of the hammer 13.

[0022] 1, two nuts 30, 30 are screwed into the thread groove 26 of the second main body portion 25, and a first coil spring 40 is interposed between the nuts 30, 30. Here, the first coil spring 40 is held in an elastically compressed state along the longitudinal direction of the second main body portion 25 by the two nuts 30, 30.

[0023] 2(c), the nut 30 is a nut having a screw groove formed on the inner peripheral surface of a cylinder and an outer peripheral surface shape of a hexagon. The outer peripheral surface shape does not have to be hexagonal, but it is preferable that it is hexagonal in consideration of ease of work when adjusting the frequency of the impact noise at the work site, which will be described later.

[0024] 2(d), the first coil spring 40 is a coil spring having an inner diameter that allows the second main body portion 25 to be inserted therethrough. The wire diameter, pitch, etc. of the first coil spring 40 are set appropriately.

[0025] Furthermore, a small diameter portion 29 having a smaller diameter than the second body portion 25 is provided at the tip of the second body portion 25. The second coil spring 50 is attached to this small diameter portion 29, and the expansion and contraction direction of the second coil spring 50 coincides with the longitudinal direction of the second body portion 25. As a result, the second coil spring 50 expands and contracts along the operating direction (reciprocating direction) of the hammer 13. In addition, the second coil spring 50 protrudes forward from the small diameter portion 29 in a state where it is attached to the small diameter portion 29. As a result, the tip of the second coil spring 50 is a free end. This second coil spring 50 corresponds to the tip of the impact applying tool 1 according to the present invention. That is, the impact tool 10 of this embodiment is used with the tip of the second coil spring 50 in contact with the workpiece W, as described later.

[0026] The second coil spring 50 is a coil spring having an inner diameter that allows it to be attached to the small diameter portion 29 of the second main body portion 25 (see FIG. 2(D)), and has a smaller diameter than the first coil spring 40. The wire diameter, pitch, etc. of the second coil spring 50 can be set appropriately, and a spring having a desired elastic modulus can be applied.

[0027] Next, the main part of the present invention will be described. As shown in FIG. 1, a third coil spring 55 is joined to the base end 23 of the applicator body 20 with its extension direction coinciding with the longitudinal direction of the second body portion 25. The tip end of this third coil spring 55 is welded to the base end 23 and protrudes rearward from the base end 23. This makes the base end of the third coil spring 55 a free end. The third coil spring 55 has an outer diameter smaller than the inner diameter of the cylinder 12 and is disposed so as to be movable within the cylinder 12 and extendable within the cylinder 12. The third coil spring 55 corresponds to the coil spring according to the present invention.

[0028] 3, the hammer 13 reciprocating inside the cylinder 12 collides with the third coil spring 55, and the hammer 13 does not collide with the tool body 11. As a result, the impact generated when the hammer 13 reciprocates and collides is transmitted to the applicator body 20 via the third coil spring 55, so that no strong impact is transmitted to the applicator body 20, and only the vibration generated when the hammer 13 collides with the third coil spring 55 is transmitted.

[0029] The third coil spring 55 is configured to expand and contract within a range that allows elastic deformation. That is, the third coil spring 55 is a coil spring whose elastic coefficient is set so that adjacent wound portions do not come into contact with each other due to the impact of the hammer 13 (see FIG. 3(C)). The third coil spring 55 pushes the hammer 13 backward by the elastic force generated by the impact of the hammer 13 when it is elastically compressed (see FIG. 3(C)→(B)→(A)), thereby improving the backward movement speed (double-acting speed). The third coil spring 55 is a coil spring having an outer diameter smaller than the inner diameter of the cylinder 12 (see FIG. 2(D)), and is smaller in diameter than the first coil spring 40. The wire diameter, pitch, etc. of the third coil spring 55 are appropriately set so that the third coil spring 55 has the elastic modulus described above. In this embodiment, the third coil spring 55 and the second coil spring 50 are coil springs having approximately the same diameter.

[0030] In the impact tool 10 of this embodiment, the compressed air supplied to the inside of the cylinder 12 is controlled to repeatedly reciprocate the hammer 13 inside the cylinder 12, whereby the hammer 13 and the third coil spring 55 collide repeatedly, causing the applicator body 20 to vibrate in the longitudinal direction (the operating direction of the hammer 13). This vibration can be propagated to the workpiece W via the second coil spring 50 of the impact applicator 1. According to this impact tool 10, the hammer 13 collides with the third coil spring 55 without colliding with the applicator body 20 of the impact applicator 1, so that noise caused by the collision can be reduced and damage to the hammer 13 and the applicator body 20 can be prevented.

[0031] Furthermore, as described above, the third coil spring 55 increases the double-action speed of the hammer 13, so that the number of times the hammer 13 reciprocates per unit time can be increased compared to the conventional configuration described above. This makes it possible to increase the amount of energy transmitted from the impact applicator 1 to the workpiece W per unit time without increasing the amount of compressed air supplied. Therefore, the impact tool 10 of this embodiment can significantly improve the efficiency of the operation of vibrating the workpiece W and save energy.

[0032] Moreover, the impact tool 10 transmits the impact force generated by the reciprocating motion of the hammer 13 to the workpiece W via the second coil spring 50. Only the second coil spring 50 contacts the workpiece W, and the impact applicator body 20 (impact applicator 1) does not contact it. As a result, by reciprocating the hammer 13, the tip of the second coil spring 55 wobbles within a predetermined range and transmits vibrations to the workpiece W. Therefore, it is possible to prevent the strong impact force generated at the moment the hammer 13 hits from being directly transmitted to the workpiece W. By disposing the second coil spring 50 in this way, complex vibrations can be transmitted to the workpiece W, and as described later, by using the workpiece W containing casting sand, the casting sand can be easily broken down.

[0033] The second coil spring 50 can apply vibrations not only in the direction of elastic contraction but also in a direction different from the direction of elastic contraction (for example, a direction perpendicular to the direction of elastic contraction) while mitigating the impact force transmitted to the workpiece W. This makes it possible to prevent damage to the workpiece W and transmit vibrations of various frequencies to the workpiece W. Furthermore, the first coil spring 40 contributes to mitigating the impact generated by the reciprocating motion of the hammer 13, thereby further reducing noise. Furthermore, the first to third coil springs 40, 50, 55 are easy to replace, making maintenance easy to perform.

[0034] Next, the casting sand removing device 60 will be described with reference to Fig. 4. This casting sand removing device 60 corresponds to the impact applying device according to the present invention. The casting sand removing device 60 is configured as a system including a workpiece holding section 60a that holds a workpiece W containing casting sand, and the impact tool 10 of the above-mentioned embodiment. The workpiece holding section 60a has a coil spring group 61 including a plurality of coil springs that elastically compress in different directions, and the workpiece W is held by the coil spring group 61. The impact tool 10 is in a state in which the tip of the second coil spring 50 mentioned above is in contact with the workpiece W. By applying an impact force to the workpiece W in this state, the casting sand adhering to the workpiece W crumbles, and the casting sand can be suitably removed from the workpiece W.

[0035] The casting sand removal device 60 of this embodiment is configured to include the impact tool 10 described above, and can therefore achieve the same effects as those of the impact tool 10.

[0036] In the impact tool 10 of the embodiment described above, the structure for joining the third coil spring 55 to the base end 23 of the applicator body 20 is not limited to the embodiment, and can be modified as appropriate as long as the tip end of the third coil spring 55 is joined to the base end 23. For example, a small diameter portion protruding rearward can be provided on the base end 23, and the third spring 55 can be fitted onto the small diameter portion and joined to the small diameter portion. Similarly, the structure for mounting the second coil spring 50 can also be modified as appropriate.

[0037] In the impact tool 10 of the above-mentioned embodiment, the wire diameter, pitch, etc. of the first to third coil springs 40, 50, 55 can be changed as appropriate. This allows the frequency of the impact sound propagating to the outside to be changed, and for example, the frequency of the impact sound can be set to a frequency that is not recognized as noise. By appropriately replacing the first to third coil springs 40, 50, 55 in this way, it is easy to adjust the impact force applied by the hammer 13 and the vibration transmitted to the impact application tool 1. These first to third coil springs 40, 50, 55 can be replaced with appropriate ones depending on the workpiece W and the work site. The wire diameter, pitch, etc. of the third coil spring 55 can be changed as appropriate within the range of the elastic coefficient shown in the above-mentioned embodiment.

[0038] In addition, in the impact tool 10 of the above-mentioned embodiment, if the hammer 13 is changed or the impact sound changes depending on the workpiece W, the positions of the two nuts 30, 30 screwed into the impact application tool 1 can be changed to adjust the length of the first coil spring 40, thereby making it possible to appropriately change the frequency of the impact sound.

[0039] Further, in the impact tool 10 of the above-described embodiment, the impact applying tool may not be provided with the second coil spring at the tip thereof, but may instead have another tip portion that abuts against the workpiece W.

[0040] Furthermore, the above-described embodiments and other examples are applied to air-type impact tools that use compressed air as a power source, but are not limited to this and can also be applied to hydraulic or electric tools, etc.

[0041] The impact tool 10 of the above-described embodiment is not limited to the task of removing casting sand from a workpiece W that contains the casting sand, and can be used for other purposes. For example, the impact tool 10 can be used as an impact tool for compacting concrete or soil, and can achieve the same effects as those of the embodiment. [Explanation of symbols]

[0042] 1 Impactor 10 Impact Tools 11 Tool body 12 cylinders 13 Hammer 20 Applicator body (long member) 23 Proximal end 40 First coil spring (tip of impact applying tool) 50 Second coil spring (coil spring) 60 Casting sand removal device (impact application device)

Claims

[Claim 1] a tool body including a cylinder and a hammer that reciprocates within the cylinder; an impact applying tool attached to the tip of the cylinder for transmitting the impact force generated by the reciprocating motion of the hammer to the workpiece; An impact tool comprising: The impact applying tool is An application tool body having a tip portion in contact with the workpiece and a base portion inserted into the cylinder, the application tool body being movable along an operating direction in which the hammer reciprocates; a coil spring that is joined to a base end of the application tool body and that expands and contracts within a range that allows elastic deformation in the actuation direction within the cylinder; Equipped with An impact tool characterized in that when the hammer collides with the coil spring, an impact force is transmitted to the applicator body via the coil spring, and when the impact force is generated, the hammer and the applicator body are not in contact with each other due to the coil spring.

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