EP2960374B1 - Working device with stamping mechanism or percussion mechanism with crossed crank drive - Google Patents

Description

The invention relates according to claim 1, a working device, for example, for compacting, ramming, hitting or breaking.

For example, a rammer for soil compaction serving as an implement is known in which a ground contact plate is set in swinging motion. For this purpose, a stamping unit is provided, which is driven by a drive motor. Other implements are, for example, break hammers in which a percussion drive is driven by a drive motor, which acts on a tool, for example a chisel.

The stamping works or percussion often have a basically similar structure. Thus, the rotational movement of the drive motor via a crank mechanism and a connecting rod in an axial (linear) reciprocating motion of a drive piston coupled to the connecting rod is converted. The movement of the drive piston in turn is usually transmitted via a spring device to the actual tool, for example, the ground contact plate or the chisel. As spring means metallic springs, such as coil springs, but also air springs can be used. In particular, in percussion, the properties of air springs have proved to be particularly suitable, while in stamping plants preferably metal springs are used.

It has proven to be expedient if the single impact energy, ie the energy that is transmitted to the tool per working stroke of the drive piston, can be varied. This gives the operator of the implement the opportunity to adjust the impact energy to his respective work needs.

In the case of the implements described above, this option is not easy. Here, the single impact energy can only vary by changing the drive speed. For example, to reduce the single impact energy, the drive or motor speed must be reduced. This has the disadvantage that the beat frequency, ie the number of beats per unit time is reduced, causing the tamper slower or a hammer beats less often. Thus, as desired, the single impact energy can be reduced, but also the overall performance of the device is unnecessarily greatly reduced.

Another way to change the single impact energy is to reduce the radius of a crank pin on the crank mechanism. The crank pin represents the connection between the crank mechanism and the connecting rod. A variability of the radius of the crank pin, however, requires a complex mechanism, which can be disadvantageous.

From the DE 10 2008 035 298 A1 It is known to drive a drive piston by two juxtaposed engines simultaneously, which are each connected via a crank mechanism and a connecting rod to the drive piston. The engines are operated in opposite directions, which increases the smoothness and thus the comfort of the implement.

From the EP 2 017 038 A1 is a hand tool with pneumatic percussion known, in which a piston is displaceable over a eccentrically mounted on an eccentric connecting rod in a reciprocating motion. The axis of rotation of the eccentric wheel is spaced at a distance perpendicular to the impact axis.

The invention has for its object to provide an implement in which in a simple manner the single impact energy is variable without the beat frequency, ie the number of strokes or strokes per unit time is changed.

The object is achieved by a working device with the features of claim 1. Advantageous embodiments are specified in the dependent claims.

A working device with a drive, a drive-driven crank drive, which is rotatable about a crank axis, and with a driven by the crank drive via a connecting rod, along a working axis reciprocable drive piston for effecting a working movement, characterized in that the crank axis and the working axis are arranged such that they do not intersect.

While usually the crank axis and the working axis are aligned with each other, so that the crank axis intersects the working axis, this is not the case with the working device according to the invention.

Rather, the crank axle is arranged in a plane which is perpendicular to the working axis, wherein the crank axle and the working axle are arranged with an offset (Deachsierung) to each other.

The working axis is usually also the axis of movement of the drive piston driven tool, so for example the stamp axis or the striking axis. It corresponds to a main axis or central axis of the implement.

The offset creates the effect that the drive piston moves at different speeds linearly, depending on the direction of rotation of the crank mechanism and whether the crank pin belonging to the crank pin connecting the crank mechanism with the connecting rod, in its movement in the working direction (direction of impact, tamping direction ) moves on the side of the offset or on the opposite side. On the side of the offset, the crank mechanism and thus the drive piston moves faster in the working direction than in one Crank mechanism without misalignment, so that an increased single impact energy can be generated. Thus, an increased single impact energy can be achieved at the same drive speed and thus constant beat frequency.

When the engine rotation direction and thus the driving rotational direction of the crank gear is reversed, the crank pin is in the drive direction (working direction) on the side opposite to the offset when driving the drive piston, whereby the drive piston is moved slower. This leads to a reduction of the single impact energy.

The energy from the crank mechanism is transmitted to the tool via the spring device when the drive piston moves in the working direction, ie in the direction of the bottom or in the direction of the material to be processed. In order to achieve a high speed of the drive piston and thus a high single impact energy, must - as explained above - the crank pin of the crank mechanism move on the side of the offset in the working direction. Reversing the direction of rotation of the drive will cause the crankpin to move in the direction of operation on the opposite side of the drain, where the drive piston is forced to lower speed, resulting in lower single impact energy.

For this reason, it is advantageous if the drive has a motor whose direction of rotation is reversible. The motor may thus be, in particular, an electric motor, in which a reversal of the direction of rotation can be realized at any time without problems.

While at the DE 10 2008 035 298 A1 two drive motors were present, which act in parallel or symmetrical to each other simultaneously via respective crank drives the drive piston, in the present implement only a drive motor is required. The implement can thus be operated with exactly one motor to achieve the effects described above.

If the motor is an electric motor, an energy store can be provided for supplying the electric motor with electrical energy.

A motor axis serving as a rotation axis of the motor may be arranged in a plane which is perpendicular to the working axis, wherein the motor axis and the working axis are either arranged so that they are spaced apart with respect to each other, or wherein the motor axis and the working axis arranged they can be cut. Thus, also the engine with respect to the working axis off-center, so with offset, be arranged. This may be useful, for example, to achieve a favorable weight distribution within the implement.

It can be sought, for example, that the center of gravity of the entire implement comes to rest as far as possible on the working axis in the intended working position, in spite of the disengagement of the crank drive. By a further offset of the engine with respect to the working axis can thus be compensated by the Deachsierung of the crank mechanism displacement of the center of gravity, so that the focus is again all on the working axis.

This ensures that the implement is substantially balanced above the tool, so that the operator can run the implement without much effort. In particular, the operator then only needs to support the weight of the implement, since the weight can be essentially carried by the tool.

Likewise, it is also possible to arrange the motor on the working axis, so in such a way that the motor axis and the working axis intersect.

The energy store can be arranged on the implement in order to compensate for a weight shift resulting from the offset of the crank axis and / or the motor axis with respect to the working axis. Thus, with a skillful choice of the location of the energy storage can be achieved that the overall center of gravity of the implement is located on the working axis, resulting in the above advantages.

Usually, a transmission is provided between the engine and the crank mechanism to transmit the torque from the engine shaft to the crank mechanism. In this case, depending on the embodiment, and the engine speed can be over or understated.

In principle, it is also possible to dispense with a variant of a transmission and drive the connecting rod directly from the engine, that is, with the help of a mounted on the motor shaft crank disk. In this case, the motor would then also be arranged eccentrically to the working axis.

An input device may be provided for prescribing a direction of rotation of the motor and / or a speed of rotation of the motor by an operator. As already explained above, the direction of rotation plays an essential role in the setting of the single impact energy. Depending on the direction of rotation of the engine and thus The location of the crankpin as the drive piston advances in the tooling direction (on the side of the drain or on the opposite side) achieves greater or lesser single impact energy.

By simply switching the direction of rotation of the motor, the operator can set the desired single impact energy.

In addition, with a change in the speed of the engine, the operator can influence not only the single impact energy but also the total impact power over a certain period of time. For example, it may be advantageous to work with a low single beat energy but a higher beat rate.

The operator thus has the option of more precisely adapting the single impact energy and the total energy to the respective substrate to be worked. By means of the choice of the direction of rotation of the motor, therefore, the coarse adjustment of the single impact energy can be made. By means of the variation of the speed then takes the fine adjustment. It is thus possible to adjust the single impact energy over a wide range, without the implement would be uncomfortable to use because of too high or too low speeds.

In a variant, a controller may be provided for changing the direction of rotation of the motor and / or for changing the speed of the motor. While in the variant described above, the operator can make the respective setting, it is possible in the variant described now to have the setting automatically carried out by the controller. Thus, the controller can automatically adjust the speed of the motor to the respective ground, but for example, the preselection of the operator with respect to the direction of rotation of the motor is observed. For example, it may be provided that there is no change in the direction of motor rotation, even if the controller recognizes that a higher or more favorable compression would be achieved with the other direction of rotation.

The working movement may be imposed on a tool coupleable to the drive piston, wherein detection means may be provided for detecting a state of the substrate being processed by the tool due to a response of the tool during a work operation. In this case, a controller may be provided for automatically changing the rotational speed of the motor as a function of the detected state of the substrate by the detection device, wherein an input device may be provided for setting a direction of rotation of the motor by the operator.

The drive piston may act on a motion conversion device for transmitting movement of the drive piston to a tool coupled to the motion conversion device. The movement-changing device can, for example, have a spring device in order to convert the rigid sinusoidal movement of the drive piston into a movement of the tool which is more suitable for the working operation, that is to say in particular a stamping or striking movement.

The implement may be a soil compaction device, for example a rammer, in which case the motion conversion device has a stamping unit. Alternatively, the implement may be a percussion device, in which case the motion conversion device has a percussion mechanism.

The offset or the Deachsierung the crank axis and the working axis can be fixed by the crank mechanism and in particular the distance of the crank pin (connecting rod) to the crank axis, ie the crank radius. However, it is also possible in a variant, to make the crank radius variable.

The Deachsierung is fixed in one embodiment and fixed. In one variant, the Deachsierung can also be realized variably, so that the operator at least when presetting the implement has the opportunity to exert over the Deachsierung, ie the axial offset of the crank axle and drive axle, a coarse impact on the later desired single impact energy.

A change of the Deachsierung can be achieved for example by the impactor or stamping unit with its surrounding housing is displaceable perpendicular to the working axis relative to the crankcase surrounding the crankcase.

The distance between the working axis and the crank axis, ie the Deachsierung can be selected in a suitable manner and in dependence on the other machine parameters. For example, the override may be in a range between zero and crank radius, where crank radius is the distance between a crankpin driving the connecting rod and the crank axle. In particular, the Deachsierung can be about half of the crank radius or in a range between 5 and 50% of the crank radius.

A disallowing greater than the crank radius, however, does not appear appropriate.

Fig. 1

in schematischer Seitenansicht das Antriebssystem eines Stampfers zur Bodenverdichtung in einer ersten Betriebsart;

Fig. 2

das Antriebssystem von Fig. 1 in einer zweiten Betriebsart;

Fig. 3

das Antriebssystem eines Aufbruchhammers in einer ersten Betriebsart; und

Fig. 4

das Antriebssystem von Fig. 3 in einer zweiten Betriebsart.

These and further advantages and features will be explained in more detail below by means of examples with the aid of the accompanying figures. Show it:

Fig. 1

a schematic side view of the drive system of a rammer for soil compaction in a first mode;

Fig. 2

the drive system of Fig. 1 in a second mode;

Fig. 3

the drive system of a breaker in a first mode; and

Fig. 4

the drive system of Fig. 3 in a second mode.

Fig. 1 shows the drive system of a rammer for soil compaction.

The drive system has an electric motor 1 serving as a drive, with a motor axis 2. Coaxially to the motor shaft 2 extends a motor shaft, not shown, on which a drive pinion 3 is arranged. The drive pinion 3 drives a crank mechanism 4 with a crank disk 5, on which a crank pin 6 is arranged. The crank mechanism 4 is rotatable about a crank axis 7 and is rotationally driven by the drive pinion 3. For this purpose, a toothing is provided externally on the crank disc 5, in which the drive pinion 3 can engage.

The crank pin 6 is coupled to a connecting rod 8, which in turn is connected via a connecting rod 9 with a drive piston 10 hinged. The drive piston 10 in a guide 11 axially and linear back and forth guided.

The drive piston has a collar 12, against which rest above and below spring assemblies 13 which transmit the reciprocating motion of the drive piston 10 on a stand 14 with a bottom contact plate 15. The soil contact plate 15 is finally used in a known manner of soil compaction.

The operation of a stamping unit, with the drive piston 10, the guide 11, the collar 12, the spring assemblies 13 and the padfoot 14 has long been known, so that further explanation is unnecessary at this point.

The reciprocating motion of the drive piston 10 defines a working axis 16, along which also the padfoot 14 serving as a tool can be moved back and forth.

As Fig. 1 shows, the crank axis 7 is arranged in a plane which is perpendicular to the working axis 16. In addition, the crank axis 7 and the working axis 16 with an offset, ie a Deachsierung V arranged to each other.

As Fig. 1 shows the Deachsierung V be about half of the crank radius, wherein the crank radius is the distance between the crank axis 7 and a central axis 6a of the crank pin 6. Depending on the configuration, however, a different value between zero and the crank radius may also make sense.

By Deachsierung the working axis 16 relative to the crank axis 7 is achieved that the single impact energy is increased. This is explained as follows:
It is assumed that the crank mechanism 4 rotates in the direction of rotation D about the crank axis 7. Then the crank pin 6 drives the connecting rod 8 and thus the drive piston 10 along the working axis 16 down. Due to the Deachsierung and the geometric conditions of the crank mechanism 4, the drive piston 10 is moved at a higher speed down than would be the case if no Deachsierung V vorläge, so the crank shaft 7 and the working axis 16 would be arranged so that they intersect ,

During the return movement of the crank pin 6, a slower movement of the drive piston 10 is effected upward.

Fig. 2 shows the same drive system, but in a mode in which the direction of rotation D 'is reversed to the direction of rotation D. The crank pin 6 is located on the opposite side of the Deachsierung V.

Since the drive path over a longer angle of rotation of the crank disc 5 and thus takes place over a longer path of movement of the crank pin 6, more time is available for the movement of the drive piston 10, which causes a reduced drive speed.

If the direction of rotation D of the crank mechanism 4 and thus of the crank pin 6 is reversed, the single impact energy can thus be considerably reduced.

This is achieved in that the crank pin 6 causes the drive piston 10 to be lowered over a larger angular range when the direction of rotation D 'is reversed relative to the direction of rotation D, so that the latter moves downwards at a lower speed.

During the return movement with the reverse direction of rotation D ', the crank pin 6 passes over a smaller angular cut-out, as a result of which the drive piston 10 is moved back relatively quickly, ie, upwards.

Fig. 3 shows the drive system of a demolition hammer with a striking mechanism.

Functionally identical components as in the stamping plant of Fig. 1 and 2 are marked with the same reference numerals. To drive the connecting rod 8, the same drive principle is used as in the FIGS. 1 and 2 ,

Accordingly, the connecting rod 8 drives the drive piston 10, which is within the guide 11 back and forth.

Coaxially with the drive piston 10, a percussion piston 17 which can be moved freely back and forth is provided which strikes the end of a chisel 18 serving as a tool. Between the drive piston 10 and the percussion piston 17, an air spring 19 is formed in a known manner, which transmits the sine movement of the drive piston 10 in the striking motion of the percussion piston 17. The structure of such impact mechanism is widely known from the prior art, so that a further description is not required.

Also in the in the Fig. 3 and 4 shown hammer mechanism are the working axis 16 and the crank shaft 7 by an offset, so a Deachsierung V arranged to each other.

Thus, depending on the direction of rotation D or D 'of the crank mechanism 4, a high or a low single impact energy can be effected.

When the crank gear 4 rotates with the crank pin 6 in the direction of rotation D, a high speed of movement of the drive piston 10 is effected, thereby providing the percussion piston 17 with a high single impact energy. If, on the other hand, the direction of rotation is reversed to the indicated direction of rotation D (direction of rotation D 'in FIG Fig. 4 ), the drive piston 10 moves at a lower moving speed, resulting in a lower single impact energy of the percussion piston 17 on the bit 18 result.

Both the direction of rotation of the electric motor 1 and its speed can be changed depending on the embodiment. For this purpose, corresponding input means may be provided with the aid of which the operator can change the direction of rotation and / or the rotational speed. It is also possible that the operator determines only the direction of rotation via an input means, while the speed through an automatic control is set depending on the nature of the material to be processed.

Claims (11)

1. Working device, comprising

   - a drive (1);

   - a crank drive (4) which is driven by the drive (1) and can be rotated about a crank axis (7); and comprising

   - a drive piston (10) for producing a working movement, which drive piston is driven by the crank drive (4) via a connecting rod (8) and can be moved in a reciprocating manner along a working axis (16);

   - the crank axis (7) and the working axis (16) being arranged in such a manner that they do not intersect each other;

   - the drive (1) has precisely one motor, the direction of rotation of which is reversible; and wherein

   - a controller is provided for changing the direction of rotation of the motor (1) and/or for changing the rotational speed of the motor (1).
2. Working device as claimed in claim 1, wherein

   - the crank axis (7) is arranged in a plane which is perpendicular to the working axis (16); and wherein

   - the crank axis (7) and the working axis (16) are arranged with an offset with respect to one another.
3. Working device as claimed in claim 1 or 2, wherein the motor is an electric motor.
4. Working device as claimed in claim 3, wherein an energy storage device is provided for supplying the electric motor with electrical energy.
5. Working device as claimed in any one of the preceding claims, wherein

   - a motor axis (2) which serves as an axis of rotation of the motor (1) is arranged in a plane which is perpendicular to the working axis (16); wherein

   - the motor axis (2) and the working axis (16) are arranged in such a manner that they are spaced apart from one another with an offset; or wherein

   - the motor axis (2) and the working axis (16) are arranged in such a manner that they intersect each other.
6. Working device as claimed in any one of the preceding claims, wherein the centre of gravity of the entire working device in the operable state lies on the working axis (16).
7. Working device as claimed in any one of the preceding claims, wherein the energy storage device is arranged on the working device in such a manner as to compensate for a weight shift which is produced by the offset of the crank axis (7) and/or the motor axis (2) in relation to the working axis (16).
8. Working device as claimed in any one of the preceding claims, wherein an input device is provided for specifying a direction of rotation of the motor (1) and/or a rotational speed of the motor (1) by an operator.
9. Working device as claimed in any one of the preceding claims, wherein

   - the working movement is imposed upon a tool (14, 18) which can be coupled to the working piston (10);

   - a detection device is provided for detecting a state of the ground, which is being worked by the tool (14, 18), by reason of a response behaviour of the tool (14, 18) during a working operation;

   - a controller is provided for automatically changing the rotational speed of the motor (1) in dependence upon the state of the ground detected by the detection device; and wherein

   - an input device is provided for specifying a direction of rotation of the motor (1) by an operator.
10. Working device as claimed in any one of the preceding claims, wherein the drive piston (10) acts upon a movement conversion device (13, 17, 19) for transferring the movement of the drive piston to a tool (14, 18) which is coupled to the movement conversion device.
11. Working device as claimed in any one of the preceding claims, wherein

    - the working device is a ground compaction apparatus and the movement conversion device has a tamping mechanism; or wherein

    - the working device is a striking apparatus and the movement conversion device has a striking mechanism.

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