EP2392413A2 - Vibration ram - Google Patents

Abstract

The vibrating hammer has a vibration generator, where shaft groups (1,2) are connected with a drive such that the rotation speed of a shaft group is half the rotation speed of another shaft group. The ratio of the static moments of the shaft groups is between six to one and ten to one. The shaft groups are provided with imbalance groups. An independent claim is also included for a method for inserting a profile into the ground using a vibrating pile driver.

Description

The invention relates to a vibratory hammer with a vibration generator, comprising two, three or four wave groups, on which at least two imbalance groups are arranged and which are connected to at least one drive, by which they are rotated at different speeds in rotation. The invention further relates to a method for introducing a profile into a ground by means of a vibrating hammer.

In construction, vibratory rams are used to bring objects such as profiles into the ground or to pull them out of the ground. The soil is excited by vibration at a frequency above the natural frequency of the soil and thus reaches a "pseudo-liquid state". By static load the pile can then be pressed into the ground. The vibration is characterized by a linear movement and is generated by pairwise counter-rotating imbalances.

The vibration generators of such vibratory rams are linearly acting vibration exciters whose centrifugal force is generated by rotating imbalances. These vibration exciters move at a variable speed. The size of the unbalance is also called a static moment. The course of the velocity of the linear vibration exciter corresponds to a periodically recurring function, in particular a sine function. Due to the sinusoidal course of the force generated by means of the rotating unbalanced masses a temporally offset alternately acting in and against the direction of advance drive is generated. This is ultimately determined by static forces, in particular dead weight and static loads. Without the superimposition of the vibration with static forces, the pile would not move forward, but would merely swing back and forth. A disadvantage of the known systems that the piling process with the aforementioned sinusoidal force curve has a considerable energy consumption, the is additionally increased by friction of the pile in the ground. The energy used for the vibrator causes virtually no propulsion.

The invention aims to remedy this situation. The invention is based on the object to provide a vibrating hammer with a vibrator, which allows an energy-efficient directional force in the forward direction. According to the invention, this object is solved by the features of the characterizing part of patent claim 1.

With the invention, a vibrating hammer is provided with a vibration generator, which allows a directed force in the direction of advance. By coupling at least two wave groups with a speed ratio of 2: 1 and a ratio of the static torque of between 6: 1 and 10: 1, a directional characteristic in the direction of advance is generated by superposition of the sinusoidal force characteristics generated by the rotating imbalances. In the direction of advance, there is a much greater maximum force compared to the opposite direction. Since during the ramming process the ground can not follow the large acceleration in the direction of ramming, the pile rips off the resonating ground with each forward momentum impulse. Due to this periodic decoupling of soil and pile material less energy is supplied to the ground. As a result, the vibration load of the environment is also significantly reduced.

Due to the greater maximum force in the direction of advance an acceleration of the piling process is achieved. Thus, while in the prior art vibratory rams the pseudo-liquid state of the soil is absolutely necessary, this condition must be avoided when using the vibrating ram according to the invention. It is therefore in the present case a method with other physical principles of action. On the one hand, energy-efficient operation is made possible by the considerably lower speed, and on the other hand, the speeds of the faster unbalance groups for rolling bearings are unproblematic. According to the natural frequencies of the regularly present soils, which are in the range of 20 Hz to 28 Hz, the present vibration ram at a frequency of the resulting force characteristic of the vibrator of less than 20 Hz, preferably less than 18 Hz operated.

Advantageously, the static moment of the first wave group is eight times as large as the static moment of the second wave group. As a result, a pronounced force peak is effected in the advancing direction.

The present object is further achieved by the features of claim 3. By using three wave groups on which at least three unbalance groups are arranged, the wave groups having a speed ratio of 1: 2: 3 and the ratio of the static moments of the wave groups to each other being substantially 100: 16.64: 3.68 the maximum acting force is increased by a further pronounced force peak in the direction of advance. This results in a further increase in energy efficiency, combined with an acceleration of the piling process causes. These vibratory ram has the advantages of the aforementioned embodiment of a vibrating hammer and is to operate at a speed corresponding to a frequency which is well below the natural frequency of the soil.

The stated object is further achieved by the features of claim 4. By using four wave groups on which at least four imbalance groups are arranged, wherein the speed ratio of the wave groups to one another is substantially 1: 2: 3: 4 and the ratio of the static moments of the wave groups to one another is substantially 100: 18.72: 5, 6: 1.38, a further expression of the force curve is achieved in the advancing direction. These vibratory ram has the advantages of the aforementioned embodiment of a vibrating hammer and is to operate at a speed corresponding to a frequency which is well below the natural frequency of the soil. Due to the specific arrangement of wave and imbalance groups a very fine adjustment of the desired force characteristic is possible.

In a further development of the invention means for adjusting the effective direction of the vibrator are provided. This allows adaptation of the vibrator to different process requirements such as ramming and pulling.

In an embodiment of the invention, the means for adjusting the direction of action comprise a swivel motor, via which the phase position of at least two imbalance groups rotating at different rotational speeds is variable relative to one another. As a result, a conversion of the effective direction is made possible without any necessary conversion measures.

In a further embodiment of the invention, the at least two imbalance groups are connected via gears with the pivot motor, wherein at least one imbalance group with the stator and at least one imbalance group is connected to the rotor of the swing motor. As a result, a direct adjustment of the imbalance groups on the swing motor allows.

Advantageously, the swing motor is a rotary-wing pivoting motor with a wing. This is distinguished from the 180-degree adjustable swivel motors by multiple higher torque and lower friction. Alternatively, the swing motor may also be a swivel motor with coarse thread.

Figur 1

die schematische Darstellung eines Getriebes eines Schwingungserzeugers einer Vibrationsramme für gerichtetes Vibrieren mit zwei Wellengruppen;

Figur 2

das Vibrationsgetriebe aus Figur 1 mit zusätzlichem Schwenkmotor zur Richtungsumschaltung;

Figur 3

die schematische Darstellung eines gerichtet wirkenden Getriebes mit zwei Wellengruppen, jeweils bestehend aus drei Wellen;

Figur 4

die schematische Darstellung verschiedener Varianten gerichtet wirkender Vibratorgetriebe mit:

1. a) sechswelliger, kurzer Bauform;
2. b) siebenwelliger, einfacher Bauform;
3. c) siebenwelliger, kurzer Bauform;

Figur 5

die schematische Darstellung gerichtet wirkender, richtungsumschaltbarer Vibratorgetriebe mit

1. a) sechswelliger, einfacher Bauform;
2. b) sechswelliger, kurzer Bauform;

Figur 6

die Darstellung des Vibratorgetriebes aus Figur 5 in kompakter Ausführung und

Figur 7

die schematische Darstellung eines richtungsumschaltbaren Vibratorgetriebes mit acht Wellen.

The invention is further based on the object to provide a energy-efficient method for introducing a profile in the ground by means of a vibrating hammer. According to the invention, this object is solved by the features of claim 9. Surprisingly, it has been found that by the design of the vibratory hammer according to one of the claims 1 to 8 and the operation of the slowest wave group at a speed corresponding to a frequency below the natural frequency of the soil, an acceleration of the profile movement is effected while reducing the energy input. Other developments and refinements of the invention are specified in the remaining subclaims. Embodiments of the invention are illustrated in the drawings and will be described in detail below. Show it:

FIG. 1

the schematic representation of a transmission of a vibrator of a vibration ram for directional vibration with two groups of waves;

FIG. 2

the vibration gear FIG. 1 with additional swivel motor for direction switching;

FIG. 3

the schematic representation of a directionally acting transmission with two wave groups, each consisting of three waves;

FIG. 4

the schematic representation of different variants of directionally acting vibrator gearbox with:

1. a) six-wave, short design;
2. b) seven-wave, simple design;
3. c) seven-wave, short design;

FIG. 5

the schematic representation directed acting, direction-switchable vibrator with

1. a) six-wave, simple design;
2. b) six-wave, short design;

FIG. 6

the representation of the vibrator gearbox FIG. 5 in a compact design and

FIG. 7

the schematic representation of a direction switchable vibrator gear with eight waves.

The vibration generator of a vibrating hammer selected as the exemplary embodiment are designed as vibrator gears. Such vibrators essentially consist of a housing in which gears provided with gears are rotatably mounted. The gears are each provided with imbalance masses. Such Vibratorgetriebe with rotatably mounted imbalance masses are the expert, for example from the DE 20 2007 006 283 U1 known. The following explanation The embodiments is essentially limited to the arrangement of waves and imbalance masses.

In the embodiment according to FIG. 1 are two wave groups 1, 2 arranged. The shafts 11, 12 of the shaft group 1 are provided with toothed wheels 112, 122 on which imbalance masses 111, 121 are arranged. The imbalance masses 111, 121 are executed in the same embodiment. The shafts 21, 22 of the shaft group 2 are as it were provided with gears 212, 222, on which similar imbalance masses 211, 221 are arranged. The gears 112, 122, 212, 222 are designed in such a way that, during rotation, the rotational speed of the shafts 21, 22 of the shaft group 2 is twice as great as the rotational speed of the shafts 11, 12. The imbalance masses 111, 121, 211, 221 are arranged in this way in that the static moment of the wave group 1 is eight times the static moment of the wave group 2.

In the embodiment according to FIG. 2 In addition, a pivot motor 5 is arranged, whose stator has a gear 51 and whose rotor has a gear 52. The wave groups 1, 2 are connected to each other via the swing motor 5 such that the gear 112 of the shaft 11 is engaged with the gear 52 of the swing motor 5; the gears 212, 222 of the shaft group 2 are connected to the gear 51 of the swing motor 5 in engagement. By relative pivoting of the rotor relative to the stator, the adjustment of a phase shift of the oscillations of the wave group 2 relative to the vibrations of the wave group 1 is now made possible, whereby a change in direction is adjustable. In the exemplary embodiment, the swivel motor 5 is a rotary-wing pivoting motor with a wing.

In the embodiment according to FIG. 3 are the wave groups 1, 2 of three shafts 11, 12, 13, 21, 22, 23 are formed, which are each provided with imbalance masses 111, 121, 131, 211, 221, 231. The unbalanced masses 111, 121 and 131 form the imbalance group 101, the imbalance masses 211, 221 and 232 form the imbalance group 201. The gears 112, 122, 132, 212, 222, 232 of the

Waves 11, 12, 13, 21, 22, 23 are in turn selected such that upon rotation the waves of the wave group 2 have twice the speed as the waves of the wave group 1. By displacement of the waves 21, 22, 23 of the wave group 2 a more compact design achievable (see. FIG. 4 a) ). The number of waves of the wave groups 1, 2 can also be chosen differently. In the embodiment according to FIG. 4 b) an additional shaft 24 is added with corresponding imbalance mass 241. By staggered arrangement of the shafts 21, 22, 23, 24 of the shaft group 2, in turn, a compact design can be achieved (see. FIG. 4c) ).

In the embodiment according to FIG. 5 is between the shafts 11, 12, 13 of the shaft group 1 and the shafts 21, 22, 23 of the shaft group 2, a pivot motor 5 is arranged. The unbalanced masses 111, 121 and 131 form the imbalance group 101, the imbalance masses 211, 221 and 232 form the imbalance group 201. Here, the gears 112, 122, 132 of the shaft group 1 with the gear 51 of the stator of the swing motor 5 are engaged and the gears 212, 222, 232 of the shaft group 2 are engaged with the gear 52 of the rotor of the swing motor 5. By relative rotation of the stator and the rotor of the rotary motor 5, in turn, a switching of the direction of action is possible. By staggered arrangement of the waves of the wave group 2 in turn a more compact height can be achieved (see. FIG. 5 b) ). In the exemplary embodiment, the pivot motor 5 is a rotary wing pivot motor with three wings.

In FIG. 6 is a modified structure of the aforementioned arrangement according to FIG. 5 shown, which allows a significant reduction in length, but in which instead of six waves eight waves are required, but this is reflected in a lower load on the shaft bearings and advantages in terms of recoverable centrifugal force, suitability for high speeds and lower sensitivity large angular acceleration brings with it.

To achieve the most balanced characteristic curve, an additional speed stage whose unbalances rotate at three times the speed can be used. In the embodiment according to FIG. 7 such an arrangement is based on the transmission concept according to FIG. 5 shown. This falls slightly wider, since the lower large gear 132, which drives the two juxtaposed shafts 31, 32, is shifted relative to the transmission center. When adjusting the effective direction, the angular position of the slow imbalances 111, 121, 131 and rapid imbalances 311, 321 remains unchanged. By the pivoting motor 5, the adjustment of the imbalances 211, 221, 231 medium speed over the others is possible.

In the embodiment according to FIG. 7 the ratio of the rotational speeds of the wave groups 1, 2, 3 to each other is about 1: 2: 3; the static moment of the wave groups 1, 2, 3 to each other is substantially 100: 16.64: 3.68.

With the help of the above-mentioned and claimed ratios of the speeds or the static moments to one another a very effective force in the feed direction can be achieved. This effect can be achieved even with a small change in the ratios in the range up to ten percent, but with efficiency loss. Such modifications of the ratios of the rotational speeds or the static moments to each other are also included in the patent claims, in which the ratios with the addition "substantially" are given.

Claims (10)

Vibratory hammer with a vibration generator, comprising two wave groups on which at least two imbalance groups are arranged and which are connected to at least one drive, by which they are set in rotation, characterized in that the wave groups (1, 2) with the at least one drive are connected so that the speed of the shaft group (1) is half the speed of the shaft group (2) and that the ratio of the static moments of the imbalance groups (101, 201) provided wave groups (1, 2) between six to one and ten is one, the frequency of the resultant force characteristic of the vibrator being less than 20 Hz, preferably less than 18 Hz. Vibratory hammer according to claim 1, characterized in that the static moment of the wave group (1) is eight times as large as the static moment of the wave group (2). Vibratory hammer with a vibration generator comprising three "wave groups on which at least three imbalance groups are arranged and which are connected to at least one drive, by which they are set in rotation, characterized in that the wave groups (1, 2, 3) with the connected to at least one drive, that rotational speed of the shaft group (1) is half the rotational speed of the shaft group (2) and one third of the rotational speed of the shaft group (3) and that the ratio of the static moments with the imbalance groups (101, 201, 301 ) is substantially 100: 16.64: 3.68 with the frequency of the resulting force characteristic of the vibrator being less than 20 Hz, preferably less than 18 Hz. Vibratory hammer with a vibrator, comprising four wave groups, on which at least four imbalance groups are arranged and which are connected to at least one drive, by which they are set in rotation, characterized in that the wave groups (1, 2, 3, 4) are connected to the at least one drive such that the ratio of the rotational speeds of the wave groups (1 , 2, 3, 4) to each other substantially 1: 2: 3: 4 and that the ratio of the static moments of the imbalance groups (101, 201, 301, 401) provided wave groups (1, 2, 3, 4) to each other is substantially 100: 18.72: 5.6: 1.38, wherein the frequency of the resultant force characteristic of the vibrator is less than 20 Hz, preferably less than 18 Hz. Vibratory hammer according to one of the preceding claims, characterized in that means for adjusting the effective direction of the vibration generator are provided. Vibratory hammer according to claim 5, characterized in that the means for adjusting the direction of action comprise a swivel motor (5) via which the phase position of at least two unbalance groups (101, 201) rotating at different rotational speeds is mutually variable. Vibratory hammer according to claim 6, characterized in that the at least two imbalance groups (101, 201) are connected to the pivot motor (5) via gears (232, 112), an imbalance group (13) being connected to the stator and at least one imbalance group (101). is connected to the rotor of the swing motor (5). Vibratory hammer according to claim 6 or 7, characterized in that the swivel motor (5) is a rotary vane or a swivel motor with coarse thread. A method for introducing a profile into the ground by means of a vibratory hammer, characterized in that the vibrating hammer comprises a vibrator according to one of claims 1 to 8, wherein the The slowest wave group is operated at a speed which corresponds to a fre quency, which is smaller than the natural frequency of the soil, whereby a pseudo-liquid state of the soil is avoided. A method according to claim 9, characterized in that the frequency of the resulting force characteristic of the vibrator is less than 20 Hz, preferably less than 18 Hz.

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