JP4995214B2 - Automatic hammer - Google Patents

Description

  The present invention relates to an automatic hammer, and more particularly to an automatic hammer such as an air hammer suitable for use in generating vibration by using compressed air and compacting concrete placed in a mold.

  As this type of automatic hammer, in particular, an air hammer, there is one proposed in Patent Document 1. This air hammer includes an air hammer body in which a piston built in by compressed air injection is vibrated at high speed, and a chisel (also referred to as a bit. This bit is also referred to as a bit in this specification) that is attached to the air hammer body and vibrates at high speed with the piston. )) And. The tip of the bit is abutted against the outer surface of the mold, and the trigger (trigger) provided on the air hammer body is operated to generate a vibration impact force on the bit by driving the piston. The mold is vibrated and the vibration is transmitted to the concrete placed in the mold to be compacted. The bit is formed of a metal cylindrical rod, and its tip surface is flattened so as to be in close contact with the outer surface of the mold. Patent Document 1 also proposes a bit whose tip is expanded in a conical shape so as to have a close contact area with the formwork.

JP 2000-271877 A

  The air hammer disclosed in Patent Document 1 has a configuration in which the front end surface of the bit is brought into direct contact with the mold frame, which causes a problem that the mold frame is damaged by the vibration impact force of the bit. That is, the concrete formwork is usually made of wood, and may be made of a thin wood board such as a plywood board. On the other hand, the bit of the air hammer is made of metal, and its tip surface is the end surface of a cylindrical rod or a conical shape, and its diameter is slightly larger, but when the bit tip is in contact with the formwork, vibration shock The force is concentrated on the part of the formwork against which the bit abuts. For this reason, a formwork that is mechanically weak against a metal bit will be damaged in some parts, resulting in cracks or chipping of the formwork, or holes in the formwork. Problem arises. In addition, the damaged formwork cannot be reused, resulting in high costs.

  An object of the present invention is to provide an automatic hammer capable of preventing damage to a mold by suppressing damage to the mold even when used for concrete compaction.

  The present invention includes a hammer body having a built-in vibration source driven by electricity or compressed air, a bit mounted on the hammer body and vibrated by the vibration source, and applying an impact by bringing the tip into contact with an object, An automatic hammer provided with a cushioning material for mitigating impact at the tip of the bit.

  The buffer member is made of at least urethane rubber or resin, and is integrated with the bit so as to cover at least the front end surface of the bit.

Furthermore, the automatic hammer according to the present invention includes a piston as a vibration source, a retainer that supports the bit, and a spring that elastically supports the hammer body in a state where the retainer is not in contact with the hammer body. Has a configuration in which the rear end portion of the bit is connected in a state of being screwed to each of the retainer and the hammer main body so as to be in a state of contacting the piston .

  According to the present invention, the shock applied to the object from the bit is reduced by the cushioning material provided at the tip of the bit, and the object is prevented from being damaged by excessive shock. Further, by holding the bit with the spring via the retainer, the collision force generated between the spring and the bit is reduced by the retainer, and the spring and the bit are prevented from being damaged. Thereby, when an air hammer is used for compaction of concrete, the formwork is prevented from being damaged, the concrete quality is improved, and the formwork can be reused.

1 is an external perspective view of an air hammer according to Embodiment 1. FIG. FIG. 3 is an exploded perspective view of the air hammer according to the first embodiment. Sectional drawing of the principal part of the air hammer of Embodiment 1. FIG. Sectional drawing of the modification of a bit.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an external perspective view showing the overall configuration of an air hammer AH to which the present invention is applied, FIG. 2 is an exploded perspective view of the main part of the air hammer AH of FIG. 1, and FIG. 3 is a cross-sectional view of the main part of the air hammer. is there. The air hammer AH includes, as main components, a pistol-shaped hammer body 1, a bit 2 attached to a portion corresponding to the muzzle of the hammer body 1, a retainer 3 for holding the bit 2 on the hammer body 1, and It consists of a spring 4.

  The internal structure of the hammer body 1 is substantially the same as the structure of the air hammer body disclosed in Patent Document 1, and a detailed description thereof is omitted, but at the bottom end of the grip portion 11 that can be grasped with one hand by an operator. The plug 12 which can connect the air tube extended from the air compressor which does not appear in a figure is provided, and compressed air is supplied through the connected air tube. Further, the upper portion of the hammer body 1 is configured as a cylinder portion 13 with a cylinder axis directed in the lateral direction, and the cylinder portion 13 is compressed inside the cylinder portion 13 by compressed air supplied as shown by a broken line in FIG. A piston 14 that is oscillated at high speed with a small stroke in the cylinder axis direction is housed inside. The piston 14 is configured as a vibration source in the present invention. The grip portion 11 is provided with a trigger 15, and when the operator operates the trigger 15 with a finger, compressed air is supplied to the cylinder portion 13 to vibrate the piston 14. A spiral groove 16 is formed on the outer peripheral surface of the tip of the cylinder part 13 so that one end of the spring 4 can be screwed together.

  The bit 2 is composed of a metal rod 21 having a cylindrical shape. As shown in FIG. 3, the rod tip 22 is formed in a conical shape and is expanded in diameter, and the tip surface is perpendicular to the rod axis. It is formed on a flat surface in any direction. A stopper 23 having a hook shape, a conical stopper 23 as in the tip portion, is integrally provided at a position slightly closer to the rear end from the intermediate position in the length direction of the bit 2. The stopper 23 is larger in diameter than the rod 21 but smaller in diameter than the tip 22. Further, urethane rubber 24 is integrated with the rod tip 22 by baking to have a required thickness so as to cover the tip surface or a conical peripheral surface region. This urethane rubber 24 constitutes the cushioning material in the present invention, and here, urethane rubber having a hardness of about 90 to 100 is used.

  The retainer 3 has an outer diameter dimension substantially equal to the outer diameter of the cylinder portion 13, an inner diameter dimension substantially equal to the outer diameter dimension of the stopper 23 of the bit 2, and a bottomed cylindrical body having a bottom portion 32 at the tip portion. 31 is formed. An insertion hole 33 having a diameter that allows the rod 21 of the bit 2 to be inserted but not the stopper 23 is opened in the bottom portion 32. A spiral groove 34 is formed on the outer peripheral surface of the distal end portion of the retainer 3, and the other end portion of the spring 4 can be screwed together. A cutout groove 35 having a width substantially equal to the diameter of the rod 21 of the bit 2 is formed in a part of the circumference of the retainer 3 along the cylinder axis direction, and the rod 21 of the bit 2 is passed through the cutout groove 35. Can be inserted into the cylinder of the retainer 3. A pair of small-diameter engagement holes 36 are provided in the outer surface of the bottom portion 32 with the insertion hole 33 in the radial direction, and the retainer 3 is pivoted when the spring 4 is screwed as will be described later. It is possible to engage a jig that is rotated in the rotation direction.

  The spring 4 is formed as a coil spring having a large uniform diameter and a large spring force with a large self-shape holding force, and one end 4a can be screwed into a spiral groove 16 provided at the tip of the cylinder portion 13 of the hammer body 1. It is. The other end 4 b can be screwed into a spiral groove 34 provided at the tip of the retainer 3. When the spring 4 is screwed into the spiral grooves 16 and 34 of the cylinder portion 13 and the retainer 3, the spring 4 firmly holds the retainer 3 against the cylinder portion 13 by the self-shape holding force of the spring 4. It is possible to move the retainer 3 relative to the cylinder portion 13 within a small dimension by the elastic force of the. Further, here, the one end portion 4a of the spring 4 has a protruding end 41 whose line end protrudes in the radial direction, and is used when the spring 4 is rotated around the center line.

  With reference to FIG. 3, the assembly process of the air hammer AH comprising the hammer body 1, the bit 2, the retainer 3 and the spring 4 will be described. First, the bit 2 is inserted into the retainer 3. That is, a partial region 21 a of the rod 21 on the tip side of the stopper 23 of the bit 2 is inserted into the bottomed cylindrical body 31 of the retainer 3 through the cutout groove 35 of the retainer 3. Even if the inserted bit 2 tries to move to the tip end side, the stopper 23 comes into contact with the inner surface of the bottom portion 32 of the retainer 3, and the bit 2 cannot move further to the tip end side, so that it is prevented from being detached. Next, the other end 4 b of the spring 4 is covered from the rear end side of the retainer 3, and the other end 4 b is screwed into the spiral groove 34. At this time, the retainer 3 is rotated around the cylinder axis by engaging a jig not shown in the figure with the pair of engaging holes 36 in the bottom 32 of the retainer 3, and screwed into the spring 4.

  Next, the assembled bit 2, retainer 3 and spring 4 are coupled to the cylinder portion 13 of the hammer body 1. That is, the one end portion 4 a of the spring 4 is screwed into the spiral groove 16 of the cylinder portion 13 while the rod rear end portion 21 b of the bit 2 is inserted into the cylinder portion 13. At this time, by operating the protruding end 41 provided at one end of the spring 4, the spring 4 is rotated around the center line with respect to the cylinder portion 13 together with the retainer 3, and can be screwed into the spiral groove 16. . In this way, by connecting the one end portion 4a of the spring 4 to the cylinder portion 13 by screwing, the spring force of the spring 4 is applied to the bit 2 via the retainer 3 and the stopper 23 in contact with the retainer 3. The rear end portion of the rod of the bit 2 is brought into contact with the end surface of the piston 14 built in the cylinder portion 13, and the vibration of the piston 14 is transmitted to the bit 2.

  In the air hammer AH assembled in this way, an operator using the air hammer AH grasps the grip portion 11 of the hammer body 1 with one hand, and pulls the trigger 15 with a finger, so that the built-in piston 14 is compressed by compressed air. It vibrates in the cylinder part 13, and the bit 2 is vibrated integrally with the vibration of the piston 14 in the length direction. Since the bit 2 is elastically supported by the cylinder portion 13 by the spring 4 through the retainer 3, the bit 2 vibrates in the length direction while the spring 4 is elastically deformed in the length direction by the vibration of the piston 14. If the tip of the bit 2 is brought into contact with the outer surface of the concrete mold, the mold 2 is vibrated by the vibration of the bit 2 and the concrete placed in the mold can be compacted.

  Since the end portion 22 of the bit 2 is covered with a cushioning material 24 made of urethane rubber, the impact applied to the mold by the vibration of the bit 2 is reduced by the cushioning material 24, and an excessive impact is applied to the mold. To prevent it. Further, since the tip 22 of the bit 2 is formed in a conical shape and the area of the tip is larger than the diameter of the rod 21, the impact force per unit area is reduced. This prevents a large impact force applied from the air hammer AH from being concentrated on a part of the mold, and the damage to the mold is alleviated to break the mold, such as cracks and chips, and holes in the mold. Opening is prevented, and deterioration of the placed concrete quality is prevented. Moreover, since the breakage of the mold is avoided, the mold can be reused.

  On the other hand, the spring 4 is deformed and vibrated with the vibration of the bit 2, and a collision force is generated between the spring 4 and the bit 2. In the configuration of Patent Document 1, since the bit and the spring are connected in a direct contact state, the bit and the spring are in a line contact state, and a collision force is applied to the contact portion, and the portion may be damaged. is there. In the air hammer AH of the first embodiment, the bit 2 is connected to the spring 4 via the retainer 3, and the bit 2 is held in surface contact with the retainer 3 by the stopper 23. Therefore, the collision force is not directly applied to the bit 2, and the collision force is buffered by the surface contact with the retainer 3, so that the spring 4 and the bit 2 are prevented from being damaged.

  In Patent Document 1, a string-like restricting tool is provided to restrict the amount of movement of the bit. However, in the first embodiment, the other end 4b of the spring 4 is connected to the retainer 3 in the spiral groove 34. The amount of extension deformation of the spring 4 can be adjusted and restricted by appropriately adjusting the lengthwise dimension of the spring 4 screwed into the spiral groove 34, and the amount of movement of the bit can be reduced without providing a restricting tool. It is possible to regulate, and the configuration of the air hammer can be simplified.

(Embodiment 2)
FIG. 4 is a diagram showing a modification of the bit, and the same reference numerals are given to the parts equivalent to those in the first embodiment. In FIG. 4A, the tip surface 22a of the tip portion 22 of the bit 2A is formed into a convex curved surface such as a spherical surface, and the surface thereof is covered with a cushioning material 24. As in the first embodiment, the cushioning material 24 is formed by baking urethane rubber. By making the distal end surface 22a a curved surface, the distal end surface 24a of the cushioning material 24 also becomes a curved surface, and even when the air hammer is pressed against the surface of the mold from different angular directions, a constant contact state is always obtained, Since a certain vibration can be applied to the mold, workability is improved and a certain compaction effect is obtained.

  FIG. 4B shows a state in which a resin cushioning material is integrally attached to the front end surface of the bit 2. Here, the buffer material is configured as a buffer block 24A in which, for example, ABS resin is formed in a block shape, and a circular concave hole 24b is opened on the back surface of the buffer block 24A. Further, a cylindrical projection 25 is formed on the flat distal end surface of the distal end portion 22 of the bit 2, and the projection 25 is press-fitted into the recessed hole 24b of the buffer block 24A and integrated. It is possible to prevent the press-fitted buffer block 24 </ b> A from falling off by providing a wedge-shaped engagement piece 25 a that protrudes in the outer diameter direction on a part of the circumference of the tip edge of the protrusion 25. Since the buffer block 24A has a simple fitting structure and is easy to replace, unlike the baking process, if the buffer block 24A is prepared in advance, it is always preferable to replace the buffer block that has deteriorated due to wear or the like in the field. It can be used in the state.

  In the embodiment, urethane rubber or ABS resin is used as the cushioning material in the present invention. However, any material can be used as the cushioning material in the present invention as long as the material can be transmitted to an object such as a mold by reducing the vibration of the bit. Is possible.

  In the embodiment, the present invention is applied to an air hammer driven by compressed air by a piston. However, the present invention can also be applied to a so-called electric hammer driven by electric energy. Further, the hammer body can be applied to the hammer of the present invention as long as it has a vibration source that generates a vibration force by electric energy or compressed air even if it does not have a piston.

  The present invention can be applied to various automatic hammers as well as automatic hammers for use in vibrating a formwork as in the embodiment as long as the automatic hammer is configured to vibrate a bit with electric or compressed air.

AH Air hammer 1 Hammer body 2 Bit 3 Retainer 4 Spring 11 Grip part 13 Cylinder part 14 Piston 23 Stopper 24, 24A Shock absorber

Claims (1)

A hammer body with a built-in piston as a vibration source driven by electricity or compressed air, and a bit attached to the hammer body and vibrated by the piston , with the tip abutting against an object and applying an impact. an automatic hammer comprising, a retainer for supporting the bit, the retainer and a spring that elastically supported by the hammer body in a state that does not contact with the hammer body, the spring, the rear end of the bit The retainer and the hammer body are connected to each other so as to be in contact with the piston, and the impact integrated into the bit so as to cover at least the front end surface of the bit is reduced. An automatic hammer comprising a cushioning material made of urethane rubber or resin.

Images