Portable hammering machine

Abstract

This portable hammer hammering machine comprises a body and an engine. The body includes a crankcase in which a crank mechanism is installed, a cylindrical part which is connected to a lower part of the crankcase by a screw means and extends in a vertical direction, and a hammering mechanism which is installed in the cylindrical part and is driven to reciprocate in the vertical direction by the crank mechanism. The engine is mounted on a side surface of the crankcase and applies rotational power to the crank mechanism. The upper part of the engine is supported with respect to the crankcase through an elastic member, and the lower part of the engine is supported through an elastic member with respect to a bracket extended from the body. The base end part of the bracket is fixed to the body through use of a screw means for connecting the crankcase and the cylindrical part.

Description

Portable hammering machine

[0001] The present invention relates to a portable striking work machine.

[0002] Patent Document 1 discloses an engine breaker as an example of a portable impacting work machine. The engine breaker disclosed in Patent Document 1 includes a main body and an engine, such as a small gasoline engine, attached to the side of the upper part of the main body. The main body houses a crank mechanism that converts the rotational output of the engine into reciprocating motion and a hammer unit that is reciprocated via the crank mechanism. The hammer unit is configured to continuously impact a workpiece supported reciprocally on the lower part of the main body. The continuous impact force applied by the hammer unit allows the workpiece to break up solid objects such as concrete. This engine breaker generates intense vibrations in the main body during impact operation. To prevent engine malfunction or damage to the connection between the main body and the engine due to such intense vibrations, vibration-damping measures are provided between the main body and the engine.

[0003] The engine's output shaft extends horizontally, and its rotational output is input to the crank mechanism of the main body. The first vibration-proofing measure is that the engine's output shaft and the crank mechanism's input shaft are connected via a flexible joint. The flexible joint allows for axial displacement of the engine's output shaft relative to the crank mechanism's input shaft. The second vibration-proofing measure is that an elastic member is interposed between the main body and the engine when the engine is supported on the main body. A mounting member is fixedly attached to the engine, having a vertical portion extending between the output shaft side and the main body side, and a horizontal portion extending from the lower portion of the vertical portion around to below the bottom of the engine. A bracket extends downward along the horizontal portion of the mounting member, and is fixedly connected to the side of the main body by screwing a vertically bent base. The upper part of the engine is supported by an elastic member interposed between the vertical portion of the mounting member and the side of the main body, and the lower part of the engine is supported by an elastic member interposed between the bracket and the horizontal portion of the mounting member.

[0004] The bracket is fixed to the main body by screwing its vertically bent base end to the side of the main body. However, this requires drilling threaded holes in the side of the main body, which increases the number of steps required. Furthermore, since the bracket must connect the horizontal and vertical parts via a bent part, it must be quite sturdy, with increased thickness and weight, to withstand the vertical bending stress caused by the weight of the engine and the vibrations that occur in the main body during the hammering operation. This increases the weight of portable engine breakers, which are desired to be lightweight.

[0005] Japanese Patent Application Laid-Open No. 2003-145446

[0006] The present invention was conceived in light of the above circumstances, and its objective is to reduce the number of manufacturing steps and make the machine lighter in a portable percussion work machine that is equipped with an engine and has anti-vibration measures in place.

[0007] In order to solve the above problems, the present invention employs the following technical means.

[0008] That is, the portable impact work machine provided by the present invention is a portable impact work machine including a main body including a crankcase that houses a crank mechanism, a cylindrical section that is connected to the bottom of the crankcase by a screw means and extends in the vertical direction, and a impact mechanism that is housed in the cylindrical section and driven back and forth in the vertical direction by the crank mechanism, and an engine that is mounted on the side of the crankcase and provides rotational power to the crank mechanism, wherein the upper part of the engine is supported by the crankcase via an elastic member and the lower part is supported by a bracket that extends from the main body via an elastic member, and the base end of the bracket is fixed to the main body using a screw means for connecting the crankcase and the cylindrical section.

[0009] In a preferred embodiment, the screw means is provided at a plurality of locations spaced apart in a direction parallel to the output shaft of the engine, and the base end of the bracket is fixed to the main body using the plurality of screw means.

[0010] In a preferred embodiment, the screw means are located at four vertices of a rectangle surrounding the axis of the cylindrical portion, and the bracket includes a pair of approximately horizontally extending portions, each of which has its base end fixed to the main body at two locations using the screw means.

[0011] In a preferred embodiment, the engine includes a mounting member having an upright portion that runs along a surface facing the crankcase and a horizontal portion that extends from a lower portion of the upright portion, the upper portion of the upright portion being supported on the crankcase via an elastic member, and the horizontal portion being supported on the bracket via an elastic member.

[0012] In a preferred embodiment, the main body includes a support plate that extends above the top surface of the crankcase on the side of the crankcase facing the engine, and the upper part of the engine is supported against the support plate via an elastic member.

[0013] Other features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the drawings.

[0014] Fig. 2 is a plan view of the portable striking work machine shown in Fig. 1, which is a front view of the portable striking work machine according to one embodiment of the present invention. Fig. 3 is a partial side cross-sectional view taken along line III-III in Fig. 1. Fig. 4 is a rear view of the portable striking work machine shown in Fig. 1. Fig. 5 is a cross-sectional view taken along line VV in Fig. 1. Fig. 6 is an enlarged cross-sectional view taken along line VI-VI in Fig. 1. Fig. 7 is an exploded perspective view of a bracket. Fig. 8 is a side view of an elastic member for supporting an upper part of an engine on a main body. Fig. 9 is a side view of an elastic member for supporting a lower part of an engine on a main body.

[0015] Preferred embodiments of the present invention will now be described in detail with reference to the drawings.

[0016] As shown in Figures 1 to 5, the portable driving machine A1 has a main body 1 and an engine 2 mounted on the upper side of the main body 1. The engine 2 can be, for example, a small gasoline engine. Because the portable driving machine A1 is equipped with the engine 2 as its own power source, it can be carried to a desired work location and perform driving work without connecting to another power source. The portable driving machine A1 can also be configured to perform various driving work, such as an engine breaker that uses driving force to break up hard solid materials such as concrete, but in this embodiment, it is configured as a pile driver that uses driving force to drive piles B (Figure 3) into the ground.

[0017] The main body 1 has an upper crankcase 11 and a lower cylindrical portion 12, which extends vertically, and the lower space of the crankcase 11 communicates with the internal space of the cylindrical portion 12. The crankcase 11 and the cylindrical portion 12 are connected by a screw means 3. The screw means 3 is also used to fix the base end of a bracket 5, which supports the lower portion of the engine 2 via an elastic member 42, to the main body 1, as will be described in detail later.

[0018] 3, the crankcase 11 houses a crank mechanism 110 including a rotatably supported pinion shaft 111, an idler gear 113 that rotates in mesh with a pinion 112 provided at the tip of the pinion shaft 111, a crank gear 114 that rotates in mesh with the idler gear 113, an eccentric shaft 116 provided at the other end of a crankshaft 115 that has the crank gear 114 at one end, and a crank arm 117 rotatably supported on the eccentric shaft 116. The pinion shaft 111 is concentric with the output shaft 20 of the engine 2 and extends horizontally. Accordingly, the crankshaft 115 and the eccentric shaft 116 also extend parallel to the pinion shaft 111, i.e., horizontally.

[0019] The tubular portion 12 houses a striking mechanism 120 operated by the crank mechanism 110. The striking mechanism 120 includes a cylindrical cylinder 121 provided along the inner wall of the tubular portion 12, a first piston 123 fitted into the cylinder 121 airtightly by an O-ring 122 so as to be vertically movable and to which the lower end of the crank arm 117 is swingably connected, a second piston 125 fitted into the lower part of the cylinder 121 airtightly by an O-ring 124 so as to be vertically movable, and a striking work body 127 supported so as to be vertically movable by a tubular portion 126 formed at the bottom of the tubular portion 12 so as to have an inner diameter smaller than that of the cylinder 121. The second piston 125 has a small-diameter portion 125a at its lower portion, which small-diameter portion 125a extends partially into the tubular portion 126. A cylindrical holder portion 13 is connected to the lower end of the cylindrical portion 12, into which the upper end of the pile B to be driven is inserted and held, and a flange 127a having an outer diameter corresponding to the inner diameter of the holder portion 13 is provided at the bottom of the driving work body 127. A collar 131 having an inner diameter corresponding to the thickness of the pile B to be driven is provided below the holder portion 13, and this collar 131 is prevented from falling off by a cap-shaped retaining ring 132 attached to the lower end of the holder portion 13. Various inner diameters of this collar 131 are available, and they can be replaced as needed depending on the thickness of the pile B to be driven.

[0020] The first piston 123 and the second piston 125 are both airtightly movable up and down within the cylinder 121, so that an airtight air chamber S is formed between the first piston 123 and the second piston 125. The first piston 123 is driven up and down by the crank mechanism 110, but as the first piston 123 moves upward, the second piston 125 is pulled up by the negative pressure generated in the air chamber S, causing it to move upward with a delay from the first piston 123. The next moment, the first piston 123 moves downward, causing a compressive force generated in the air chamber S, causing the second piston 125 to move downward at high speed and crash into the top of the striking body 127. The impact force at this time is extremely large, and by repeating this operation continuously, the striking body 127, which is in contact with the top of the pile B within the holder part 13, can effectively drive the pile B into the ground.

[0021] The engine 2 is mounted on the main body 1 so that the direction of the axis of its output shaft 20 basically coincides with the direction of the axis of the pinion shaft 111 and extends horizontally, and vibration-proof measures are taken between the engine 2 and the main body 1.

[0022] The first vibration-damping measure is to interpose a flexible coupling 21 between the output shaft 20 of the engine 2 and the pinion shaft 111, so that the output shaft 20 of the engine 2 and the pinion shaft 111 can be displaced relative to each other in the direction perpendicular to the axis. In this embodiment, the rotational power of the engine 2 is output via a centrifugal clutch 22, and the flexible coupling 21 is interposed between a clutch drum 221 of the centrifugal clutch and the pinion shaft 111. A known flexible coupling such as that described in Patent Document 1 can be used as the flexible coupling 21.

[0023] The second vibration-proofing measure is to support the engine 2 on the main body 1 via elastic members 41 and 42, and the present invention employs a unique structure as described below.

[0024] First, a mounting member 230 is fixedly attached to the engine 2 by screws or the like. The mounting member 230 has an upright portion 231 extending between the output side surface of the engine 2 and the opposing side surface of the main body 1 (crankcase 11), and a horizontal portion 232 that wraps around from the bottom of the upright portion 231 and below the bottom of the engine 2. This mounting member 230 can be formed by bending a metal plate or the like. In this specification, the term "engine 2" is a concept that includes this mounting member 230.

[0025] On the other hand, a support plate 119 extending above the top surface of the crankcase 11 is fixedly provided on the side of the main body 1 (crankcase 11) facing the engine 2, and a bracket 5 extending below the horizontal portion 232 of the mounting member 230 is fixedly provided.

[0026] The upper part of the engine 2 is supported on the crankcase 11 by interposing elastic members 41 at two locations, left and right, between the upright portion 231 of the mounting member 230 and the support plate 119 when viewed in the direction of the output shaft 20 of the engine 2, and the lower part of the engine 2 is supported on the main body 1 by interposing elastic members 42 at two locations, left and right, between the horizontal portion 232 of the mounting member 230 and the bracket 5.

[0027] The elastic member 41 used to elastically support the upper part of the engine 2 is, for example, as shown in detail in FIG. 8 , a base plate 411 and a disk 412 with a male screw 412 a, with rubber 413 sandwiched between them by, for example, vulcanization bonding. The base plate 411 is attached to the support plate 119 with screws (not shown), and a nut 414 is screwed onto the male screw 412 a that is inserted through the upright portion 231 of the attachment member 230.

[0028] The elastic member 42 used to elastically support the lower part of the engine 2 is, for example, as shown in detail in FIG. 9, made up of two disks 422, 423 with male threads 422a, 423a, with rubber 424 sandwiched between them by, for example, vulcanization bonding. As shown in detail in FIG. 6, the elastic member 42 is provided by screwing a nut 425 onto one of the male threads 422a that passes through the horizontal part 232 of the mounting member 230, and by screwing another nut 425 onto the other male thread 423a that passes through the bracket 5.

[0029] In this embodiment, the bracket 5 is composed of a pair of left and right arm-like bracket elements 51, 52 and a connecting member 53 bridging the ends of the bracket elements 51, 52. As shown in Figures 6 and 7, the pair of left and right arm-like bracket elements 51, 52 extend substantially horizontally, and to increase bending rigidity, vertical walls 512 are integrated with the side edges of a substantially horizontal plate 511 along their entire length, thereby increasing the section modulus. The connecting member 53 is bridged between the left and right bracket elements 51, 52 by inserting a male screw 423a of an elastic member 42 used to elastically support the lower part of the engine 2 into a through-hole 531 formed in the connecting member 53 and tightening a nut 425 onto the male screw 423a. The pair of left and right bracket elements 51, 52 are positioned so as to sandwich the main body 1 from the left and right sides, and are fixed to the main body 1 using the screw means 3 that connects the crankcase 11 and the tubular portion 12 described above.

[0030] The crankcase 11 and the tubular portion 12 are connected by providing four screw through holes 128a at the vertices of a rectangle in a flange portion 128 formed outward at the upper end of the tubular portion 12, and threading bolts 14 through the screw through holes 128a from below into threaded holes 11a provided in the underside of the crankcase 11, as shown in detail in Figure 6. The base ends of the arm-like bracket elements 51, 52 extend across the tubular portion 12 in a side view, are placed on the underside of the flange portion 128, and are fixed to the main body 1 by passing the bolts 14 through two through holes 51a provided at each end spaced apart in the longitudinal direction and threading the bolts 14 into the threaded holes 11a as described above. This fixing method of threading the bolts 14 through the through holes 51a into the threaded holes 11a corresponds to the screw means 3 in this invention.

[0031] The portable driving work machine A1 according to this embodiment is provided with a handle 6 including an inverted U-shaped lifting section 61 located at the top of the main body 1 and a pair of left and right work handles 62 extending vertically from both ends of the lifting section 61. When performing pile driving work, the worker grips the pair of left and right work handles 62 with both hands. The work handles 62 are provided with an operating section 63 for adjusting the throttle opening of the engine 2.

[0032] Next, the operation of the portable striking work machine A1 having the above-described configuration will be described.

[0033] The portable hammering device A1 is gripped so that the top end of the pile set in the ground is held within the holder portion 13. At this time, the weight of the portable hammering machine A1 causes the hammering body 127 of the hammering mechanism 120 to rest on the top of the pile B (FIG. 3). When the operating portion 63 is operated to increase the rotation speed of the engine 2, the centrifugal clutch is engaged and the rotation output of the engine 2 is transmitted to the crank mechanism 110. As already explained, the hammering body 127 of the hammering mechanism 120 repeatedly hammers the top end of the pile B with a powerful hammering force. In this way, the pile B is driven efficiently into the ground.

[0034] During pile driving work using the impact force described above, the main body 1 generates strong vertical vibrations. However, because vibration-proof measures are taken by interposing elastic members 41, 42 between the engine 2 and the main body 1 (crankcase 11), the vibrations of the main body 1 are not directly transmitted to the engine 2, making it possible to avoid malfunctions or early damage to the engine 2 due to the vibrations. During work, the main body 1 and the engine 2 may move relative to each other in the vertical direction, but because a flexible coupling 21 is interposed between the output shaft 20 of the engine 2 and the pinion shaft 111, which corresponds to the input shaft of the crank mechanism 110, the rotational power of the engine 2 is transmitted without problem to the crank mechanism 110 or the impact mechanism 120.

[0035] The bracket 5 that supports the lower part of the engine 2 via the elastic member 42 is fixed to the main body 1 using a screw means 3 that uses a bolt 14 to connect the crankcase 11 and the cylindrical part 12, so there is no need to configure a separate mounting part on the crankcase 11, and the number of processing steps for the main body 1 can be reduced, thereby reducing costs.

[0036] Moreover, unlike the bracket described in Patent Document 1, the bracket 5 does not have any large bends and extends substantially horizontally, so it has essentially high bending rigidity. Furthermore, the left and right bracket elements 51, 52 in this embodiment have their vertical walls 512, 522 integrated with the side edges of the horizontal plates 511, 521, thereby increasing their section modulus. Additionally, the base ends of the bracket elements 51, 52 extend across the tubular portion 12 in a side view and are fixed to the main body 1 at two longitudinal locations with bolts 14. All of these factors contribute to increased bending rigidity, ultimately enabling the bracket 5 to be made lighter and more compact while still maintaining the necessary bending rigidity. This contributes to reducing the overall weight of the portable striking work machine A1.

[0037] Furthermore, in this embodiment, when the upper part of the engine 2 is supported on the main body 1 (crankcase 11) via the elastic members 41, the elastic members 41 are set at a higher position by the support plate 119, so that the alternating rotational moment shown by arrow M in Figure 3 acting on the engine 2 during operation can be effectively received. This also leads to an improvement in the vibration damping effect of the elastic members 41, 42.

[0038] Of course, the present invention is not limited to the above-described embodiments, and all design modifications within the scope of the claims are included within the scope of the present invention.

[0039] For example, the portable driving machine A1 according to the embodiment is configured as a pile driver, but by changing the shape of the driving body 127 to, for example, a chisel shape, it can also be configured as an engine breaker or a rammer.

[0040] The specific configurations of the crank mechanism 110, the striking mechanism 120 actuated by the crank mechanism 110, the bracket 6, etc. are also not limited to those of the embodiment.

[0041] A1 Portable hammering work machine B Pile M Rotational moment S Air chamber 1 Main body 11 Crankcase 11a Screw hole 110 Crank mechanism 111 Pinion shaft 112 Pinion 113 Idler gear 114 Crank gear 115 Crank shaft 116 Eccentric shaft 117 Crank arm 118 Holder portion 119 Support plate 12 Cylindrical portion 120 Striking mechanism 121 Cylinder 122 O-ring 123 First piston 124 O-ring 125 Second piston 125a Small diameter portion 126 Cylindrical portion 127 Striking work body 127a Flange 128 Flange portion (upper end of cylindrical portion) 128a Screw through hole 13 Holder portion 131 Collar 132 Retaining ring 14 Bolt 2 Engine 20 Output shaft 21 Flexible coupling 22 Centrifugal clutch 221 Clutch drum 230 Mounting member 231 Upright portion 232 Horizontal portion 3 Screw means 41 Elastic member (upper portion) 411 Base plate 412a Male screw 412 Disk 413 Rubber 414 Nut 42 Elastic member (lower portion) 422a Male screw 422 Disk 423a Male screw 424 Rubber 425 Nut 5 Bracket 51 Bracket element 51a Through hole 511 Horizontal plate 512 Vertical wall 52 Bracket element 53 Connecting member 531 Through hole 6 Handle 61 Lifting portion 62 Work handle portion 63 Operation portion

Claims

1. A portable impact work machine comprising: a crankcase housing a crank mechanism, a tubular section connected to the bottom of the crankcase by a screw means and extending in the vertical direction, a striking mechanism housed in the tubular section and driven to reciprocate in the vertical direction by the crank mechanism; and an engine mounted on a side of the crankcase and providing rotational power to the crank mechanism, wherein an upper portion of the engine is supported by the crankcase via an elastic member, and a lower portion of the engine is supported by a bracket extending from the main body via an elastic member, and the base end of the bracket is fixed to the main body by using a screw means for connecting the crankcase and the tubular section.

2. A portable percussion work machine as described in claim 1, wherein the screw means is provided at a plurality of locations spaced apart in a direction parallel to the output shaft of the engine, and the base end of the bracket is fixed to the main body using the plurality of screw means.

3. A portable percussion work machine as set forth in claim 2, wherein the screw means are positioned corresponding to the four vertices of a rectangle surrounding the axis of the cylindrical portion, the bracket includes a pair of approximately horizontally extending portions, and each of the approximately horizontally extending portions has its base end fixed to the main body at two points by the screw means.

4. A portable percussion work machine as described in claim 3, wherein the engine includes a mounting member having an upright portion along a surface facing the crankcase and a horizontal portion extending from a lower portion of the upright portion, the upper portion of the upright portion being supported on the crankcase via an elastic member, and the horizontal portion being supported on the bracket via an elastic member.

5. A portable percussion work machine as described in claim 4, wherein the main body includes a support plate extending above the upper surface of the crankcase on the side of the crankcase facing the engine, and the upper part of the engine is supported on the support plate via an elastic member.