JP2000257018A - Rammer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the breakage factors of coil springs and main body components by using the coil springs having such a shape that pitches of coil strands are changed nonuniformly along the longitudinal direction against a load and the deflection quantities of the springs are gradually changed from one end toward the other end. SOLUTION: Coil springs 10 are arranged in an upper space section and a lower space section across a rod end in the leg inner cylinder of a rammer. Each coil spring 10 is wound with a coil strand 13 of a fixed size into a coil shape in a uniform outer diameter size from the lower end 14 to the upper end 15 so that the pitch and pitch angle of the strand 13 are gradually increased from the lower end 14 to the upper end 15 to form the nonuniform-pitch coil spring 10. When a load is applied, the strand 13 is gradually crimped in the longitudinal direction, an effective section as the spring 10 is changed as time elapses, thus the apparent spring constant is gradually increased, and the impact force when the strand 13 is wholly stuck is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a rammer used for compacting various types of ground and road surfaces.

[0002]

2. Description of the Related Art As a conventional rammer, for example, as shown in FIG. 5, an outer cylinder 3 slidable below a power transmission mechanism 31 for changing the rotating motion of a motor 30 into a vertical motion.
3 and an inner cylinder 34, and a crimping plate 35 at the lower end of the leg 32. The vertical movement of the power transmission mechanism 31 is performed by a piston rod 36 to move the leg inner cylinder 3
4 and the vertical movement of the inner cylinder 34 is transmitted to the pressing plate 35 via the elasticity of a coil spring 37 disposed in the inner cylinder 34 (for example, a real machine). No. 1-84307).

In a conventional rammer, a coil spring 37 for imparting elasticity, which is disposed in an inner cylinder 34 constituting the leg portion 32, has the same coil outer diameter after winding a wire 38 at both upper and lower ends. Further, a coil spring in which the pitch and the pitch angle between the element wires 38 of the effective portion as the spring are uniform at both upper and lower ends has been used.

[0004]

In the coil spring 37 in the conventional rammer as described above, the load acting on the compacting plate 35 from the prime mover 30 via the coil spring 37 and the coil from the ground via the compacting plate 35 Since each pitch between the coil wires 38 between the upper and lower ends is uniformly changed by receiving the load acting on the spring 37, the rotation speed of the prime mover 30 is increased to increase the number of hits to the ground by the pressing plate 35. When the jumping force of the pressing plate 35 is increased, all the coil wires 38 between both ends of the coil spring 37 come into close contact at a time when a certain number of hits is reached.

As described above, when all the coil wires 38 between both ends of the coil spring 37 come into close contact at once, the load of the moving part of the rammer main body is not attenuated by the spring force of the coil spring 37. In addition, the impact is temporarily applied to the rammer main body, and the impact may damage the coil spring 37 and the main body components. Therefore, in the conventional rammer, as a means for preventing such an obstacle, it is necessary to provide a cushioning material 39, 40 such as rubber in a portion which is susceptible to an impact, and to take measures to prevent damage due to the impact.

[0006] Further, the rammer is used according to the purpose of the work.
It is sometimes used when compacting soft ground and when compacting relatively hard road surfaces paved with asphalt or the like. When compacting soft ground, the compacting plate 3 is used.
So that the jump amount of 5 is large and a strong hitting force can be obtained,
The spring force of the coil spring 37 is required to be high, and the vibration force of the vibrator is also required to be large. On the other hand, when compacting a relatively hard road surface, the amount of jump of the pressing plate 35 is required in order to finish the road surface as flat as possible. In order to obtain the stability of the fuselage by reducing the force, it is required that the spring force is not hard and the vibration force is small.

[0007] As described above, the fact that the spring force and the vibration force of the coil spring 37 are required to be different depending on the purpose of work means that the design features are mutually contradictory. Since it is impossible to satisfy these two conditions, conventional rammers are used for compacting soft ground using hard springs and for compacting hard roadbed using soft springs. There was a problem that two different types had to be manufactured.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the conventional rammer, the present invention provides a coil spring disposed in the leg inner cylinder of the rammer, in the length direction with respect to the load. By using a coil spring with a shape in which each pitch between coiled wires does not change uniformly and the amount of deflection of the spring gradually changes from one end to the other end, the coil can be used when a load is applied. When the wire is gradually crimped along the length direction and the effective portion as a spring changes over time, the apparent spring constant is gradually increased, and as a result, when all the coil wires are in close contact It is an object of the present invention to provide a rammer capable of reducing the impact force of the coil spring and reducing the breakage rate of the coil spring and the body parts.

The rammer according to the present invention includes, as specific means for this purpose, a leg comprising an outer cylinder and an inner cylinder which are slidable below a power transmission mechanism for changing the rotational motion of the prime mover into a vertical motion, and this leg. A vertical press by the power transmission mechanism is transmitted to the leg inner cylinder via a piston rod, and the vertical motion of the inner cylinder is transmitted through the elasticity of a coil spring disposed in the inner cylinder. In the rammer transmitted to the pressing plate, a coil spring having a shape such that the amount of deflection of the spring due to a load gradually changes from one end to the other end is disposed in the inner cylinder.

As a coil spring in which the amount of deflection of the spring due to a load gradually changes from one end to the other end,
It is preferable to use an unequal-pitch coil spring in which the coil outer diameter after winding the wire from one end to the other end is equal, and the pitch and pitch angle between the coil wires gradually increase and decrease.

As the coil spring in which the amount of deflection of the spring due to the load gradually changes from one end to the other end, a conical coil spring in which the coil outer diameter after winding the wire changes from one end to the other end in a conical shape. May be used.

The rammer has a leg portion comprising an outer cylinder and an inner cylinder slidable below a power transmission mechanism for changing the rotational motion of the motor into a vertical motion, and a crimping plate at the lower end of the leg portion. A piston rod extends into the leg inner cylinder from the power transmission mechanism, and includes an upper space portion and a lower space portion sandwiching the rod end at the lower end of the piston rod in the inner cylinder. A configuration in which a pair of unequal pitch coil springs are arranged in the space is preferable.

In the same manner as described above, the rammer has a leg portion comprising an outer cylinder and an inner cylinder which are slidable below a power transmission mechanism for changing the rotational motion of the motor into a vertical motion, and a lower end of the leg portion. A piston rod extending from the power transmission mechanism into the leg inner cylinder, and an upper space portion and a lower space portion sandwiching the rod end at the lower end of the piston rod in the inner cylinder. The configuration may be such that a pair of conical springs are arranged in each of the space portions such that the end portion having the smaller outer diameter of the coil is in contact with the rod end.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the rammer according to the present invention is as follows.
Referring to the embodiment shown in the drawings, as shown in FIG. 1, this rammer has a power transmission mechanism 2 for changing a rotary motion into a vertical motion on a side surface of a prime mover 1 such as an engine. A leg 3 is formed by slidably inserting an inner cylinder 5 having a lid 5a at an upper end into an outer cylinder 4 projecting downward, and the lower end of the inner cylinder 5 forming the leg 3 is formed. In the inner cylinder 5, a piston rod 7 whose lower end is located at the center of the inner cylinder 5 is provided in the inner cylinder 5. Is extended.

The piston rod 7 extending into the inner cylinder 5
At the lower end, a flange-like rod end 8 is provided, and an upper space portion 9a and a lower space portion 9b sandwiching the rod end 8 are defined in the inner cylinder 5, and each space portion 9a , 9b have the same coil spring 1
0 are arranged respectively.

Outside the outer cylinder 4 enclosing the inner cylinder 5, a cylindrical protect sleeve 1 whose lower end is fixed to the pressing plate 6 and whose inner peripheral surface slides on the outer peripheral surface of the outer cylinder 4.
The bellows 12 is attached between the upper end of the protect sleeve 11 and the lower end of the power transmission mechanism 2, and lubricating oil is sealed inside the protect sleeve 11.

As shown in FIG. 2, each of the coil springs 10 disposed in the upper space 9a and the lower space 9b sandwiching the rod end 8 in the inner cylinder 5 has a constant thickness. The coil wire 13 is wound in a coil shape with a uniform outer diameter from the lower end portion 14 to the upper end portion 15, and the pitch and pitch angle between the coil wires 13 are from the lower end portion 14 to the upper end portion 15. An unequal-pitch coil spring formed so as to gradually change greatly is used.

The unequal pitch coil spring 10 includes:
In the upper space 9a and the lower space 9b sandwiching the rod end 8 of the inner cylinder 5, an upper end 15 having a large pitch and a large pitch angle between the wires 13 comes into contact with the upper and lower surfaces of the rod end 8, and The pitch between the lines 13 and the lower end portion 14 having a small pitch angle are arranged so as to be in contact with the lid 5 a and the pressing plate 6 at the upper end of the inner cylinder 5.

In the rammer shown in FIG. 1, the unequal-pitch coil springs 10 are attached to the upper space 9a and the lower space 9b of the inner cylinder 5 by an upper end 15 having a large pitch between the wires 13 and a large pitch angle. Are arranged so as to be in contact with the upper surface and the lower surface of the rod end 8, but the unequal pitch coil springs 10 are arranged in the upper space 9a and the lower space 9b in the directions described above. It is not limited to only.

For example, although not shown, contrary to the above arrangement, the lower end 14 having a small pitch and a small pitch angle between the strands 13 is arranged in such a direction as to contact the upper and lower surfaces of the rod end 8. One unequal coil spring 10 has an upper end 15 having a large pitch and pitch angle between the wires 13 in contact with the upper surface of the rod end 8, and the other unequal coil spring 10 has a pitch and pitch angle between the wires 13. The small lower end 14 may be oriented such that it contacts the lower surface of the rod end 8, or the respective unequal coil springs 10 may be oriented in the opposite direction.

FIG. 3 shows the construction of another embodiment. In this rammer, the above-mentioned unequal space is formed in an upper space 9a and a lower space 9b sandwiching a rod end 8 in an inner cylinder 5. A coil spring 20 having a different shape from the pitch coil spring 10 is disposed.

As shown in FIG. 4, the coil spring 20 disposed in the upper space 9a and the lower space 9b of the inner cylinder 5 of the rammer has a coil wire 23 having a constant thickness. A conical coil spring is used which is wound in a coil shape at the same pitch from the portion 24 to the upper end portion 25, and is formed so that the coil outer diameter after winding gradually changes from the lower end portion 24 to the upper end portion 25. Have been.

The conical coil spring 20 has an upper end portion 25 having a small coil outer diameter formed by a wire 23 and an upper surface and a lower surface of the rod end 8 in the upper space portion 9a and the lower space portion 9b sandwiching the rod end 8. , The lower end 24 of the coil 23 having the larger outer diameter of the coil is covered by the lid 5 a
It is preferable to arrange them in such a direction as to be in contact with the pressing plate 6.

In the rammer shown in FIGS. 1 and 3, when the piston rod 7 descends due to the rotation of the motor 1, the coil springs 10 and 20 in the lower space 9b are compressed by the rod end 8 to push out the inner cylinder 5. As a result, the pressing plate 6 protrudes downward, and when the piston rod 7 rises, the coil springs 10 and 20 in the upper space 9a are raised.
Is compressed and the inner cylinder 5 is pulled up, so that the pressed plate 6 is lifted upward, and the vertical movement of the pressed plate 6 causes the ground to be compacted.

In the rammer shown in FIG. 1, when an unequal coil spring 10 disposed in the upper space 9a and the lower space 9b in the inner cylinder 5 receives a load from the direction of the rod end 8 or the pressing plate 6, First, the wires 13 of the lower end 14 having a small pitch and a small pitch angle begin to adhere to each other, and the wire 13 in this portion loses its effectiveness as a spring. The wires 13 of the portion 15 are not yet tightly adhered, and the tightness between the wires 13 in the portion where the pitch and the pitch angle are increased progresses with time, and as a result, the apparent spring of the entire spring As the constant increases, the impact load acting on the spring and the main body is absorbed.

On the other hand, in the rammer shown in FIG. 3, when the conical coil spring 20 disposed in the upper space 9a and the lower space 9b in the inner cylinder 5 receives a load from the rod end 8 or the pressing plate 6, First, the lower end 2 having a large outer diameter
4 begin to adhere to each other, and the wire 23 in this portion loses its effectiveness as a spring. At this point, the wire 23 of the upper end portion 25 having a small outer diameter is still in close contact. However, the spring constant of the upper end portion 25 having a smaller outer diameter is larger than that of the lower end portion 24, and the amount of bending gradually decreases as the load reaches the upper end portion 25. As a result, the apparent spring constant of the entire spring increases, and the impact load acting on the spring and the main body is effectively absorbed.

When the conical coil spring 20 is used as the coil spring, the upper end 25 having a smaller coil outer diameter is provided on the upper and lower surfaces of the rod end 8 with respect to the upper space 9a and the lower space 9b. When the coil springs 20 are arranged so as to be in contact with each other, the upper end portion 25 having a small outer diameter engages with the lower end of the piston rod 7 and the shaft end 7a projecting from the lower surface of the rod end 8, so that the coil spring 20 swings by the load. In this way, the contact with the inner cylinder 5 can be prevented, and mutual friction can be prevented and vibration stability can be achieved.

[0028]

According to the rammer of the present invention, a coil spring having a shape in which the amount of deflection of the spring due to a load gradually changes from one end to the other end is disposed in the inner leg cylinder. Initially, the amount of bending is constant, but the adhesion between the wires progresses with time from the larger bending amount to the smaller bending amount, and the apparent spring constant of the entire spring against the load Can be absorbed to absorb the impact load, so that rubber and other buffers to prevent obstacles caused by the impact load, like a conventional rammer using a coil spring with the same outer diameter, pitch, and pitch angle, can be used. There is no need to provide a material, and cost can be reduced.

Furthermore, in the conventional rammer for use in compacting soft ground, it was necessary to use a hard coil spring for the purpose of increasing the jump force of the compacting plate. However, in the rammer of the present invention, When the coil spring receives a load, the amount of deflection of the spring between the upper and lower ends does not change uniformly, but changes with time from one end to the other end, and the apparent spring constant of the entire spring with respect to the load is reduced. Since it can be increased, it can endure a large load, and there is no need to use a particularly hard coil spring.

Further, in the conventional rammer, for the purpose of compacting a hard roadbed such as an asphalt pavement surface, a soft material is used for the purpose of reducing the jumping force of the compacting plate and performing a stable compacting operation. It was necessary to reduce the eccentricity of the vibrator by using a coil spring. However, in the rammer of the present invention, the load of the coil spring causes the amount of deflection of the spring to change with time from one end to the other end. Therefore, if the number of revolutions of the engine is reduced, an appropriate spring bending action can be exerted within a range in which a required compaction force is obtained, and in particular, a soft coil spring may be used. Also, there is no need to reduce the amount of eccentricity of the exciter.

Therefore, according to the rammer of the present invention, a hard coil spring is used for compacting a soft ground like a conventional rammer, and a soft coil spring is used for compacting a hard roadbed. It is not necessary to use different coil spring springs according to the application, such as using, and a single rammer provides a versatile and economical rammer that can be used for both compaction of soft ground and compaction of hard roadbed can do.

[Brief description of the drawings]

FIG. 1 is a partially longitudinal side view showing the configuration of one embodiment of a rammer according to the present invention.

FIG. 2 is a side view showing a shape of a coil spring used in the rammer of FIG. 1;

FIG. 3 is a partially longitudinal side view showing the configuration of another embodiment of the rammer according to the present invention.

FIG. 4 is a side view showing a shape of a coil spring used in the rammer of FIG. 3;

FIG. 5 is a partially longitudinal side view showing the configuration of a conventional rammer.

[Explanation of symbols]

 1: prime mover 2: power transmission mechanism 3: leg 4: outer cylinder 5: inner cylinder 6: pressed plate 7: piston rod 8: rod end 9a: upper space 9b: lower space 10: unequal pitch coil spring 11 : Protective sleeve 12: Bellows 13: Coil wire 14: Irregular pitch coil spring lower end 15: Irregular pitch coil spring upper end 20: Conical coil spring 23: Coil element wire 24: Conical coil spring lower end 25: Conical coil Spring upper end

Claims (5)

[Claims] 1. A power transmission mechanism for changing a rotational motion of a motor into a vertical motion, a leg portion comprising an outer cylinder and an inner cylinder which are slidable below a power transmission mechanism, and a presser plate at a lower end of the leg portion, wherein In a rammer, the up-and-down movement of the transmission mechanism is transmitted to the leg inner cylinder via a piston rod, and the up-and-down movement of the inner cylinder is transmitted to the pressing plate via elasticity of a coil spring disposed in the inner cylinder. A rammer wherein a coil spring having a shape such that the amount of deflection of the spring due to a load gradually changes from one end to the other end is disposed in the inner cylinder. 2. A coil spring in which the amount of deflection of a spring due to a load gradually changes from one end to the other end.
2. An unequal-pitch coil spring in which a coil outer diameter after winding of a wire is equal from one end to the other end, and a pitch and a pitch angle between the coil wires gradually increase and decrease.
Rammer. 3. A coil spring in which the amount of deflection of a spring due to a load gradually changes from one end to the other end.
2. A conical coil spring in which the outer diameter of the coil after winding of the element wire changes conically from one end to the other end.
Rammer. 4. A power transmission mechanism for changing the rotational motion of the prime mover into a vertical motion, a leg portion comprising an outer cylinder and an inner cylinder slidable below the power transmission mechanism, and a presser plate at the lower end of the leg portion. A piston rod extends from the transmission mechanism into the leg inner cylinder, and a pair of unequal pitch coil springs are disposed in the upper space and the lower space sandwiching the rod end at the lower end of the piston rod in the inner cylinder. The rammer of claim 1 or 2, wherein 5. A power transmission mechanism for changing the rotational motion of a prime mover into a vertical motion, a leg portion comprising an outer cylinder and an inner cylinder which are slidable below a power transmission mechanism; A piston rod extends from the transmission mechanism into the leg inner cylinder, and a pair of conical springs are provided in the upper space and the lower space sandwiching the rod end at the lower end of the piston rod in the inner cylinder, respectively. 4. The rod end is arranged so that a small end of the rod is in contact with the rod end.
Rammer.