EP1012403B1 - Working machine with reduced upper mass vibrations - Google Patents

Description

The invention relates to a working device according to the preamble of claim 1. In particular, the invention relates to a ramming device for soil compaction or a hammer.

Known rammers of this type are constructed so that a motor and a crank mechanism receiving the upper mass via a spring set with a essentially a working mass forming a working or compaction plate connected is. The rotary motion generated by the motor is converted into an oscillating axial movement by the crank mechanism transfer to the worktop for soil compaction via the spring set becomes. The upper mass comprises about two thirds and the striking working mass a third of the total mass of rammers, while that of the upper mass and the distances traveled by the working mass in reverse Stand in relation to each other. The upper mass moves in one Size range from 25 to 30 mm.

The vibrations of the upper mass are transferred to the transferring the implement leading person, especially in the case of long periods Working is very uncomfortable. Are particularly stressful for the operator thereby vibrations in the horizontal or lateral direction. vibrations in the vertical direction, on the other hand, are for efficient work of the Stammerers required.

Fig. 2 shows such a known rammer.

2, a drive shaft 1 of a motor, not shown of the rammer, which is driven by a pinion 2 in the rammer housing mounted and provided with external teeth crank disc 3 drives. On the crank disc 3, a crank pin 4 is attached to the one Connecting rod 5 is rotatably mounted. The connecting rod 5 is at its other End by means of a piston pin 6 rotatably with a guide piston 7 connected. The guide piston 7 carries one through a steel disc formed and fastened by a nut 8 piston guide 9. The guide piston 7 is with the piston guide 9 within one to the lower mass belonging guide tube 10 axially back and forth. This axial direction corresponds to a vertical or working direction of the device during its Insert.

On both sides of the piston guide 9 is a multi-spring Spring set 11 arranged, the springs on each of their Piston guide 9 facing away from the guide tube 10 attached Spring plates 12 are supported. To block the spring sets 11 to avoid, a damping sleeve 13 is above the piston guide 9 an elastic plastic material placed on the guide piston 7. while below the nut 8 also made of elastic plastic existing damping plug 14 is attached. The damping sleeve 13 and the damping plug 14 can with heavily compressed spring sets 11 each with its side facing away from the piston guide 9 to the associated one Strike the spring plate 12. They then dampen the further compression movement such that a block seating of the spring sets 11 and thus one too strong impact on the implement is avoidable.

The guide tube 10 with the spring plates 12 belongs to the working or undersize of the rammer. A not shown in Fig. 3 can on the lower mass Pad foot are attached, which is used for soil compaction. To do that The upper mass is to prevent penetration of moisture and dirt and the lower mass connected by an elastic bellows 15.

As can be seen from Fig. 2, the rotational movement of the motor by Crank drive by means of the crank disk 3. the crank pin 4 and the connecting rod 5 converted into an oscillating axial movement of the guide piston 7. This Axial movement is via the spring sets 11 on the guide tube 10 and thus transferred to the lower mass and can be used for soil compaction become.

It was previously used to dampen vibrations affecting the operator known, the guide bracket against the upper mass by means of rubber elements to decouple mechanically. The attached drive motor remains but still exposed to high vibration loads. An improvement Vibration damping can only be achieved by high structural Effort can be achieved.

It is therefore desirable to have vibrations in the upper mass to avoid from the outset.

From DE-OS 19 25 870 a rammer for soil compaction is known with a working mass from an engine belonging to an upper mass is linearly reciprocated via a double crank mechanism. Around To reduce the vibrations on the upper mass, two are opposed movable weights are provided, those of the crank mechanism Vibration superimpose an opposing vibration. The pounder is double-legged, with each pounder leg having its own Crank drive is driven. Accordingly, the rammer builds a lot large and can only be used with great force on the ground to lead.

From DE-PS 753 502 is a drive device for exciting vibratory systems known. These are in a crank drive Arms and levers coupled to one another via rubber springs. A harmful dynamic mass effect in the form of on the engine and to avoid the retroactive bearing, the mass of the Arms and levers using low specific materials Weight kept as low as possible.

The invention is therefore based on the object of specifying an implement, already avoided when the upper mass vibrated can be.

According to the invention, the task is performed by a working device with the features solved by claim 1.

Surprisingly, it has been shown that when using materials, which are lighter than steel, i.e. have a lower density than steel, for the manufacture of linearly floating components the crank mechanism, in particular the connecting rod, the Guide piston and the piston guide, the vibrations of the upper mass can be significantly reduced. This is because the Mass of the upper mass due to the lower weight of the moving components is reduced, whereby lower forces act on the upper mass.

It is particularly advantageous if the material is an aluminum alloy or is a plastic material because of a particularly large reduction in mass is possible.

In the previously known tools, especially for rammers, was mostly tries to absorb the vibrations acting on the operator dampen by placing the device's guide bracket opposite the device itself vibration-insulated, for example, using rubber elements. Moreover it was known to overlap with the upper mass vibration to reduce an additional, separately generated vibration. A reduction of the vibrations as they arise by using light components, however, are not yet known.

In addition to reducing the upper mass movement, the mass reduction has the moving components also have the advantage of saving energy, because lower masses accelerate and decelerate with each crank revolution Need to become. The total weight of the device can also be reduced. Due to the lower acceleration load on the drive motor longer lifetimes achievable. On the other hand, it is the same power output of the engine possible, slightly wider or heavier ramming plates to use the same upper mass movement or acceleration. About that the running noise can also be reduced. In addition, if appropriate Manufacturing process expected significant cost reductions. However, the main advantage is the reduction of the operator acting hand-arm vibrations, which makes working more comfortable becomes possible.

In a particularly advantageous embodiment, the piston guide together with a damping bush, preferably with two damping bushes, Can be made in one piece from plastic. In addition to the mass reduction mentioned this leads to a simplification of the manufacturing process and thus also to a reduction in costs.

These and other features of the invention are described below with the help of the figures explained in more detail.

Fig. 1

einen Teil eines erfindungsgemäßen Stampfgeräts in Schnittdarstellung;

Fig. 2

einen Teilschnitt eines bekannten Stampfgeräts.

Show it:

Fig. 1

a part of a ramming device according to the invention in a sectional view;

Fig. 2

a partial section of a known ramming device.

Since essential components of the invention shown in Fig. 1 The ramming device known, already described in connection with FIG. 2 Corresponding elements, a new description is dispensed with. To simplify the figures for the same components the same reference numerals are used.

In contrast to the known tamper shown in Figure 2 are at the tamper according to the invention shown in FIG. 1 shows some of the linearly and movable components of the crank mechanism made of materials, which have a lower density than steel and are therefore lighter as steel. Depending on the size and performance of the rammer, the Decide on a case-by-case basis which components are made of lighter materials are to be produced. Basically, however, is to avoid vibrations of the upper mass to strive for as many components as possible in lightweight construction perform.

The affected components are the connecting rod 5, the Guide piston 7 and a piston guide designed according to the invention 16. The crank mechanism itself consists of the crank disc 3, the crank pin 4, the connecting rod 5, the piston pin 6, the guide piston 7 and the piston guide 16th

The connecting rod 5 can preferably be made of plastic, for example carbon fiber or glass fiber reinforced polyamide. For the guide piston 7 are wrought aluminum alloys or glass fiber reinforced Polyamide.

The connecting rod 5 made of plastic has a certain elasticity and thus spring properties. This elasticity is due to a bow leg Shape, d. H. by an arcuate course of the connecting rod 5 between the on the crank disc 3 located crank pin 4 and that on the guide piston 7 arranged piston pin 6 supports. The connecting rod 5 therefore forms an oval "O", through the center of which the drive shaft 1 extends. The lateral legs of the "O" improve the suspension or damping ability of the connecting rod 5, whereby the bearings and gears and other, with the Connecting rod 5 connected components can be spared.

The piston guide 16 integrates the one known from the prior art Piston guide made of steel, which consists of an elastic plastic material Expansion sleeve and the expansion plug in one component. The Piston guide 16 has a wider edge 17 approximately in the middle the two sides of which bear the spring sets 11. From the edge 17 goes in a sleeve in both directions, an upper expansion sleeve 18 is slipped over the guide piston 7 and a lower expansion sleeve 19th also extends in the form of a sleeve in the direction of the lower mass. To a Avoid block seating of the spring sets 11. can with strong swing strike the ends of the expansion sleeves 18, 19 against the respective spring plates 12, before the spring turns touch each other. Thereby excessive shock loading of the device is avoided. To a corresponding one To ensure damping ability through the piston guide 16 it is made in one piece from polyurethane. To reinforce the Edge 17, in particular to damage the piston guide 16 by avoiding the spring sets 11 lying on top, it is possible to thin Insert steel washers between the edge 17 and the associated springs 11.

The piston guide 16 is on the guide piston via a trapezoidal thread 20 7 screwed on. The trapezoidal thread 20 ensures a large area Contact between the piston guide 16 and the guide piston 7, see above that the local surface pressure can be kept low.

To prevent rotation, there is an internal hexagon inside the lower expansion sleeve 19 21 formed in the one having an external hexagon Steel piece 22 insertable and by means of a screw 23 on the guide piston 7 can be fixed. This arrangement ensures that the Piston guide 16 is not independent of the guide piston during operation of the device 7 can screw down.

The invention was described above using a ramming device according to the invention explained for soil compaction. The invention can also also very advantageous for a hammer, for example a hammer can be used because the impact of the hammer on the same principle as with the ramming device. The fact that the Hammer usually instead of the steel springs forming the spring sets 11 Air spring impact mechanism used has the positive effects of the invention Embodiment no influence.

The use of plastic materials can save weight of several kilograms can be achieved. This saved weight can however also be added to the upper mass, so that this opposite Devices known from the prior art increase in mass. This makes the upper mass more quiet during operation, which means fewer hand-arm vibrations transferred to the operator. The total mass of the Stampfers remains compared to the case in which the components in question are made Steel are made constant.

Claims (4)

1. Stamping device for ground compaction, having a working mass which is driven in a stamping manner and can be driven linearly in a reciprocating manner by means of a motor associated with an upper mass via a crank drive (3, 4, 5, 7, 16) and a spring assembly (11), characterised in that the crank drive comprises at least one structural element (5, 7, 16) which can be moved linearly in a reciprocating manner and is produced from a material, the density of which is less than that of steel, and that the structural element which can be moved linearly in a reciprocating manner is a structural element from the group of connecting rod (5), guide piston (7), piston guide (16).
2. Stamping device as claimed in claim 1, characterised in that the material is an aluminium alloy.
3. Stamping device as claimed in claim 1 or 2, characterised in that the material is a synthetic material.
4. Stamping device as claimed in claim 1, characterised in that the piston guide (16) together with at least one damping bushing (18, 19) can be produced in one piece from synthetic material.

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