EP3111016A1

EP3111016A1 - Method and apparatus for driving screwable foundations into the ground

Info

Publication number: EP3111016A1
Application number: EP14828485.4A
Authority: EP
Inventors: Günther THURNER; Martin Thurner
Original assignee: Krinner Innovation GmbH
Current assignee: Krinner Innovation GmbH
Priority date: 2014-02-28
Filing date: 2014-12-30
Publication date: 2017-01-04
Also published as: US9976275B2; DE102014002986B3; WO2015128048A1; CA2940890A1; US20160362864A1

Abstract

Disclosed is a method for driving a screwable foundation, which comprises a thread-type external helix that has a pitch on the outer contour thereof, into the ground. In said method, a striking force is applied to the screwable foundation in the driving direction in alternation with or at least temporarily simultaneously with a torque when the screwable foundation is driven into the ground.

Description

METHOD AND DEVICE FOR INTRODUCING SCREWING ELEMENTS

IN THE EARTH

The invention relates to a method and an apparatus for introducing Schraubfunda- elements in the soil, especially in soil of different soil conditions.

Screw foundations are used in a variety of ways and also introduced into the soil with screw-in tools of a mechanical type. Nevertheless, in order to be able to reliably bring the ground screws into the ground for a wide variety of ground conditions, i. especially when stones are in the screw of the screw foundation, the corresponding Schraubfundamente have been equipped with hardened tips or chisel-like additional tools, which are guided inside the Schraubfundamentes and serve the destruction of the stone, so to speak at the leading edge when introducing the Schraubfundamentes. In contrast, impact sleeves are known, which are merely hammered or driven into the ground by a striking tool. While only one impact device is present in impact sleeves, i. a screwing prohibits, because the impact sleeves in the longitudinal direction or Einschlagrichtung trained webs to prevent rotation, the Schraubfundamente threaded ridges have attached to their outer contour, so that they can be screwed into the ground. For wrapping are

Screw foundations therefore not suitable.

When screwing in, for the purpose of reliable anchoring, the screw-in sleeve, ie the screw foundation with the webs, should screw into the ground, but not loosen it considerably. Depending on the condition of the ground, different ridge heights were therefore developed. In order to be able to reliably introduce screw foundations in soils which are very hard or have stones as obstacles for the introduction of the screw foundations, screw foundations with open tips have been developed, in which an additional hammer which complicates the entire insertion system is introduced into the screw foundations , so that during the screwing in by means of a striking movement on the chisel leading stones in the ground may possibly be smashed or crushed. The striking movement of the chisel takes place independently of the rotational movement of the screw foundation. Due to the fact that screw foundations are screwed into the ground and, in order to ensure a reliable anchoring, should not be loosened during the screwing process, it is not possible to use turning tools and sliding tools together for the insertion of screw foundations.

Such combinations are known only for Rammbohrgeräte, which are also referred to as rotary hammers. These devices are used to create tubular earth bores and are similar in basic construction to those used for impact drills, for example, for drilling hard concrete and are well known (see DE 3911467 C2).

The basic procedure when using such rotary hammers would mean that it would be necessary to pre-drill, then a drill would have to be removed from the generated borehole in order subsequently to be able to subsequently screw in a foundation. The pre-drilling and producing a borehole for the introduction of a screw foundation, however, is also disadvantageous because, if necessary, then it can not be ensured that the screw foundation is reliably anchored, and because, moreover, although a predrilled hole for the screw foundation has been produced, However, it can not be ruled out that a stony ground condition would oppose considerable resistance to the penetration of the helices of the screw foundation, so that when screwing in even with a pre-drilled hole, the screw foundation to be introduced may possibly be damaged or even destroyed. Furthermore, from DE 36 17 025 A1 for prefabricated concrete piles known to introduce this while exerting an axial feed rate and simultaneous rotation about its longitudinal axis into the ground. In one embodiment, the feed rate and rotational movement are synchronized in accordance with the pitch of the helical fin assembly. First, the rotational speed is controlled in dependence on the traveled actual distance until some courses of the rib have taken in the ground and can be provided by merely further rotation of the concrete pile due to the support of the rib necessary for displacing the soil axial force. Then, in the first place, the rotational speed is set according to the desired feed speed. The object of the present invention is to provide a method and a device by means of which screw foundations in soils of different textures can be reliably introduced and yet reliably anchored. This object is achieved by a method having the features according to claim 1 and a device having the features according to claim 16. Advantageous developments are defined in the respective dependent claims.

In the method according to the invention, a torque and an impact force directed in the direction of insertion of the screw foundation are applied to the screw foundation alternately one after the other or at least temporarily at the same time, depending on the soil. The screw foundation has on its outer contour an outer spiral in the manner of a thread with a defined pitch. If now the screw foundation is screwed into the soil, i. not drilled, so at a given speed corresponding to the slope of the Eindringweg over time or the feed rate is theoretically determined.

The combination of screwing and driving in of screw foundations has surprisingly been found that a secure fastening of screw foundations can be ensured, especially in hard and / or stony soils, although in principle it was to be expected that the use of impact forces when screwing in screw foundations is reduced in the ground, since the borehole is widened in particular in the helical coil. This is especially true when using conventional rotary hammers used for drilling cylindrical drilled holes. Known percussion drills have a maximum torque of 750 to 3000 Nm and a striking power of up to 20 KW. From this it can be seen that the main propulsion results from the impact force and the torque is used predominantly for displacing the bit and for removing the overburden.

To ensure a safe insertion and fixing of screw foundations, the ratio of torque and impact performance in favor of the torque is changed. In particular, the maximum torque is increased compared to the aforementioned conventional Schlagbohrköpfen and held the impact performance constant or even reduced. An exemplary embodiment is a torque of 5 to 10 kNm and a punch power of about 5 kW, so that a ratio of about 1 to 2: 1 exists. By switching on the impact, for example, when hitting a stone, it is ensured that the obstacle is overcome without loosening the surrounding soil so far that a secure anchoring of the screw foundation is no longer guaranteed. It also prevents the Schraubfundament is rotated without generating more significant propulsion, and the helical coil the surrounding soil stirs and loosens, as is done when screwing without impact when hitting an obstacle. Applying the Schraubfundaments with a torque and with a striking force is preferably carried out based on a speed measurement and a longitudinal movement measurement of Schraubfundamentes. If, due to resistances or uneven ground conditions, the actual penetration path does not correspond to the theoretical value for the penetration path, then a slip value not equal to 1 is present. The slip or slip value is defined as follows: s = (np) -v ^'1 , ie speed times slope due to feedrate. Thus, a (current) slip value is preferably determined on the basis of a rotational speed measurement and a longitudinal movement measurement (feed measurement) of the screw foundation and of the gradient. The slip value is kept within predefined limits by varying the speed and switching the impact force on or off. The limits of the slip value are preferably defined in such a way that a certain deviation from the theoretically traveled penetration path is permitted, ie limits are defined as a function of the theoretically traversed penetration path. The rotational speed and the impact force are regulated in such a way that when the amount of this slip value, ie a limit of the slip value, is exceeded, the impact force is switched on or off, the control taking place such that the amount of the slip value after switching on or off is respected again. That is, the speed and the impact force are controlled to each other so that always the predetermined limits of the Schiupfwerts are not exceeded. Namely, only then can it be ensured that, on the one hand, a good penetration into the ground is ensured, ie that resistances possibly present through stones are overcome with a correspondingly slower penetration rate, but that the solid anchoring of the screw foundation with its outer spirals in the soil is not thereby eliminated. If, according to a preferred embodiment, the actual penetration path is reduced relative to a theoretical penetration path related to the current rotational speed, the impact force is switched on and the rotational speed is adapted accordingly on the basis of the longitudinal movement and the gradient. This is the case, for example, when the screw foundation encounters a hard ground area such as a stone when screwing.

Accordingly, if thereafter the obstacle in the ground is overcome, i. the stone is penetrated, for example, so is virtually the reduced longitudinal movement no longer exists, so that a normal longitudinal movement can be set, which is initially in increased

Speed affects. Determining these conditions then the impact force is switched off. Thus, it is preferably even possible by the existing method to ensure stone detection in the ground. According to a preferred embodiment, the total theoretical length traveled is determined as compared, for example, by integral formation and with the actual longitudinal path traveled by means of the screw foundation during insertion. If this actual longitudinal path is now reduced in relation to the theoretically covered longitudinal path, whereby the theoretically covered longitudinal path is determined from inclination and revolutions, the impact force is switched on and the speed reduced to such an extent that the reduced longitudinal path is adapted accordingly in the direction of the expected longitudinal path. Upon reaching a predetermined approach value to the expected, ie theoretical longitudinal path, the impact force is switched off again.

According to a further preferred embodiment, the torque exerted on the screw foundation is limited or reduced. For example, a maximum torque is predetermined by the drive or is set on the machine depending on the soil condition, the type of screw foundation and / or further introduction or boundary conditions. Preferably, therefore, the measured actual torque is compared with a predetermined maximum torque during penetration. Preferably, the speed is reduced as far as reaching the predetermined maximum torque and at the same time switched on the percussion that the predetermined maximum torque is not exceeded. Further preferably, after limiting or reducing the torque, the impact force is applied to the screw foundation until a new light torque, i. a renewed startup of the device, a propulsion in the direction of insertion is available again.

The impact force is preferably switched on when the speed drops by a predefined amount. During the introduction of the screw foundation, a substantially constant torque is demanded from the screwing tool with consistently constant soil conditions. The torque increases at best due to increasing friction on the Eindrehiefe. If the screw foundation, and in particular the tip of the screw foundation strikes a layer of hard ground or a stone or rock, the torque required increases abruptly. If this torque increase is limited by the maximum torque of the drive, the speed drops. In such a speed drop then preferably the impact force is switched on. The speed drop can be defined as a threshold value via a (negative) gradient or a speed difference. If the threshold value is exceeded, the impact force is preferably switched on automatically. Alternatively or additionally, the exceeding of the threshold value can also be displayed via a display device, for example in the form of a lamp or a display. Alternatively, the impact of the Schraubfundaments on a stone, a rock or the like is also recognizable by the abrupt increase in torque. Thus, such a behavior of the torque is detectable and usable as Einschaltbedingung for the impact force. For detection, a torque difference or a slope of the torque curve can also be defined as a threshold value.

The maximum torque and / or the threshold for the switch-on condition are preferably set as a function of the nature of the soil and / or the screw foundation to be screwed in.

This embodiment is also completely self-contained possible, i. without corresponding slip values are required as the basis for a control of the connection or shutdown of the torque or the impact force. The control is carried out on the basis of the maximum torque. When the maximum torque is reached, it is always reduced or switched off and the impact force is switched on, which can be followed by the switching on of the torque again after a corresponding penetration. In such a case, a multiple change between switching on and switching off torque and / or impact force is conceivable, so that ensures optimal insertion of the Schraubfundaments while securing a reliable anchorage by the balanced combination of switching on or Abschalte ns of torque and power becomes.

Preferably, the impact force is switched off when reaching the rated speed and when the torque falls by a predefined value.

In addition to a hammer, it is also possible that the impact force is exerted by high-frequency vibrations. The high-frequency vibrations may preferably be high-frequency or ultra-high-frequency sound vibrations. According to a second aspect of the invention, a device for introducing

Screw foundations provided in the soil, by means of which a sleeve body is introduced with on its outer sides existing outer spiral with a thread-like pitch. This device realizes the method according to the invention described above. This device comprises a rotating device for screwing the Schraubfundaments, a striking device for generating a striking force in the direction of insertion of the screw foundation, a speed measuring device for determining the current speed of the Schraubfundamentes during its introduction, further comprises a displacement measuring device for determining the Einbringweges the Schraubfundamentes and a control device for controlling the rotating device and impact device and their connection or disconnection. By means of the control device are the rotating device and the impact device during the introduction of the

Schraubfundamentes alternately or at least temporarily simultaneously operable so that by means of the control device of the current speed, the slope of the outer spiral and the Einbringweg the Schraubfundamentes certain amount of a defined slip value is not exceeded.

Preferably, the control device acts on the rotating device as speed reducing and the impact device is switched on when the Schraubfundament strikes a rock or hard ground and the actual Einbringweg is less than the current speed corresponding Einbringweg until the amount of the defined slip value is reached.

Preferably, the impact device is designed as a device which emits ultra-high-frequency vibrations in the form of a sound source. Preferably, the high-frequency vibrations can also be generated by a device which outputs mechanical vibrations.

According to a further development of the device, a torque sensor is furthermore provided by means of which the current torque can be measured, on the basis of which the rotary device can be switched off or down regulated on reaching a defined maximum permissible torque.

Preferably, the device has at least one contact surface pair, via which the torque from the motor of the rotary device can be transmitted to a drive shaft and the screw foundation. The contact surface pair is arranged on a diameter which corresponds to at least twice, in particular five times the diameter of the drive shaft. The contact surfaces of the contact surface pair are movable relative to each other, in particular in the direction of a rotation axis of the rotating device.

Further features and advantages of the invention will become apparent from the following embodiments in conjunction with the figures. Showing:

FIG. 1 shows an embodiment of a screw foundation loading device according to the invention,

FIG. 2 shows the screw foundation in a first position during screwing in, FIG. 3 shows the screw foundation in a second position during screwing in; FIG. 4 shows a flow diagram of a method according to the invention for inserting a screw foundation;

FIG. 5 shows a second embodiment of a screw foundation loading device according to the invention,

Figure 6a, b: a third embodiment of a Schraubfundament-Einbringgeräts invention, and

Figure 7 a, b, c: various embodiments of a Schraubfundaments in side view and bottom view, which can be introduced with the method according to the invention or the device according to the invention in the soil.

FIG. 1 shows an inventive feeding device 1 for introducing a screw foundation 10 into the ground 20. The screw foundation 10 has a helical spiral 11 at least in partial regions. The introduction device 1 has a carriage 2, in which a drive head 3 is arranged displaceably. By the Reiativbewegung the drive head 3 relative to the carriage 2, which is generally carried out in a substantially vertical direction, the feed V for the introduction of the screw 10 is provided. The feed V can be provided by the own weight, in particular of the drive head 3, or by an active drive with a given propulsion force and / or propulsion speed. The drive head 3 has a coupling 7, which is rotationally rigidly connected to the screw foundation 10. The coupling 7 is rotatable by the drive head 3 both in the direction of rotation R and movable in the translation direction T to perform a percussion drilling. Both a speed sensor 4 and a torque sensor 5 for measuring the introduction speed or the Einbringmoments and a displacement sensor 6 for determining the feed path and the feed rate are provided on the drive head 3 or on the feed unit 1.

FIG. 2 shows a section of the screw foundation 10 in a first position during introduction into the soil 20. In this section, the screw foundation has a thin-walled cylindrical sleeve 14 and the helical coil 11 arranged on the outside thereof. In an idealized driving-in process, in which the feed rate corresponds to the insertion feed speed, ie, the screwing speed n times the thread pitch p, the helical coil 11 cuts into the soil 20 such that both the upper and the lower flanks 12 and 13 abut in the soil 20. In real driving operations, however, the feed rate often does not match the feed rate. In the case shown in FIG. 2, the feed rate v is too small or the rotational speed n is too high. This is also referred to as positive slip, so that the factor s for the slip is greater than 1. With positive slip occurs below the lower edge 13 of the Schraubfundaments 10, a cavity 21 during insertion. This happens, for example, when the Einbringwiderstand, for example, by a stone is increased. The formation of such cavities 21, however, has a negative effect on the strength (holding force) of the

Schraubfundaments 10 in the soil 20 off. The slip is defined in the present application as follows: s = (n p) / v.

The cavity 21 is created by the fact that the real feed lags behind the ideal feed to the tail N.

By means of the method according to the invention, the wake N is to be reduced by using a particularly combined rotary and hammering or driving movement, as shown in FIG. FIG. 4 schematically shows a flowchart for a loading process according to the invention. The turning operation is started at step 100. After the start of the driving-in process, the driving-in process is monitored by means of the sensors for speed, torque and feed (4, 5 and 6). In particular, a stone recognition 110, a thread protection 120 and a Schaubfundamentschonung 130 are realized via these sensors. As shutdown condition for the introduction process, the insertion depth is monitored via the feed sensor 6. When the insertion depth is reached, the insertion process is terminated in step 150. The monitoring operations 110, 120 and 130 usually run parallel to each other. However, the individual types of control can also be implemented individually or in various combinations. For each of the monitors, there is a condition in column 101, with which the respective state is detected. In column 102, the impact device or the impact force is then switched on and the further introduction according to column 103 is regulated. Upon reaching an exit condition according to column 104, the hammer mechanism is turned off in accordance with column 105.

The stone recognition 110 has as recognition condition that a collapse of the feed rate takes place. In particular, the current slip exceeds a predetermined limit slip value, since, for example, the screw foundation strikes a rock and the feed rate is reduced abruptly. Turning on the percussion ensures that even in hard subsurface, for example in rock or rock, a feed takes place. After switching on the impact mechanism, the speed is controlled on the basis of the forward speed and a positive slip, for example with 3 = 1, 1. Due to the positive slip, the feed is quickly accelerated again after penetrating the rock. The exit condition here is the exceeding of a preset limit speed, for example 20 min ^-1 . With entry of the exit condition, the impact mechanism is switched off and the speed control is terminated.

For the thread protector 120, the detection 121 is determined on the basis of the traveled feed path and, ideally, on the basis of the number of revolutions u and the thread pitch p. As a result, the follower N is considered to be the recognition criterion. If the caster exceeds a predefined value, for example half a thread pitch p, then the percussion mechanism switches on, and speed control likewise takes place. In the given case, however, the slip s is set to a value <1, for example 0.9, d. H. regulated on negative slip. This counteracts the further destruction of the structure in the soil, in particular that an on-the-surface conveying of soil through the screw foundation 10 or the helical coil 11 takes place. As an exit condition applies here according to step 124, when the caster is reduced to zero or falls below a predefined value. Upon reaching the exit condition, the hammer mechanism is turned off and the speed control is terminated.

A third type of control is the screw foundation protection according to FIG. 130. The detection criterion according to step 131 is when a predefined maximum torque or a limit torque is reached. For example, the torsional rigidity of the screw foundation 10 or the rated power of the drive head 3 can serve as limit torque. By activating the impact mechanism, the screwing resistance of the screw foundation 10 is reduced by loosening up the soil. When the Schraubfundamentschonung becomes active, the torque is regulated to the limit torque, which may be reduced by a safety factor, according to step 133. As exit sbedi ng u ng according to step 134 here is in particular the falling below the predetermined speed limit by a predefined value at maximum speed. If, for example, the maximum torque is 3500 Nm, the limit torque for switching on can be 3000 Nm. Upon entry of the exit condition in step 134, the hammer mechanism is turned off and the torque control of step 133 is also terminated.

If the exit condition according to column 104 occurs in the three control modes 110, 120 and 130, then the program loop between the steps 100 and the monitors 1 10, 120 and 130, that is, it continues to monitor according to the steps

110, 120 and 130 instead. In addition, there is the possibility that the monitors 110, 120 and 130 are also active during a control according to column 103. FIG. 5 shows a second embodiment of the introduction device 1 according to the invention, in particular the drive of the insertion device 1 according to the invention, in which an oscillation can be introduced into the coupling 7 by means of an oscillatory movement. Between the drive head 3 and clutch 7, a sleeve 30 is rotatably mounted on the shaft. The sleeve 30 is arranged concentrically with the shaft. On the sleeve, a mass 31 is arranged as imbalance. In addition, the sleeve via a drive 32, for example an electric motor, can be driven. By displacing the mass 31 in rotation, a vibration is exerted on the clutch 7 and thus also on the screw foundation 10. The direction of rotation of the sleeve is preferably opposite to the direction of rotation of the clutch. This device can be arranged in addition to the impact boring machine shown in Example 1 on the loading machine 1 or only in combination with a boring machine. The introduction of

Vibrations, in particular vibrations, are particularly advantageous in the screw foundation protection control or in the overload protection according to step 130 in FIG. 4. However, it is also usable, for example, for penetrating rock in stone detection according to step 110 in FIG. The axis of rotation of the mass 31 is alternatively also perpendicular to the longitudinal axis of the Schraubfundaments attachable. The speed of rotation of the mass 31 is preferably between 1000 and 10,000 min. ¹

FIGS. 6a, b show a second embodiment of the introduction device 1 according to the invention, in particular the drive of the insertion device 1 according to the invention. The motor 8 of the drive head 3 is formed with a central passage 33 through which a hollow shaft 34 is passed and driven by the motor 8. Concentric with the hollow shaft 34, a drive shaft 35 is formed and passed through the hollow shaft 34. On a first side of the motor 8, a firing pin 36 is arranged, via which impact energy in the drive shaft 35 can be introduced. On the opposite second side of the engine 8, the hollow shaft 34 has two drivers 37 which form contact surfaces 39a, b with wings 38 arranged on the drive shaft. Through the hollow shaft 34 and the contact surface pairs 39a, b, the torque of the motor 8 is transmitted to the drive shaft 35. The pairs of contact surfaces 39a, b are designed such that they allow a relative movement between the hollow shaft 34 and the drive shaft 35 in the direction of their longitudinal extension during impact operation. Furthermore, the contact surface pairs 39a, b are arranged at a diameter which is significantly greater than the diameter of the two shafts. The diameter on which the contact surface pairs 39a, b are arranged corresponds approximately to 6 times As a result, the surface pressure in the contact surface pairs 39a, b is reduced, so that the friction and also the wear due to the relative movement are reduced. FIG. 7 a shows a screw foundation 10, which consists of a cylindrical, thin-walled sleeve 14. The screw foundation 0 according to FIG. 7b has a conical section in the lower region and is open towards the bottom. The screw foundation according to FIG. 7c has a thin-walled cylindrical section in the upper region and a conical section in the lower region, which terminates in a closed screw foundation tip. For solid types of soil such as sandstone are preferably open at the bottom

Schraubfundamente used, since in contrast to closed screw foundations practically only the volume of the pipe wall, but not the volume of the entire

Must displace screw foundations. Due to the already solid floor sufficient stability is guaranteed. With the screw foundations shown, the screw thread can! 11 may be arranged over the entire length of the screw foundation or only in partial areas.

Bezuaszeichenliste

1 delivery device

2 carriage

3 drive head

4 speed sensor

5 torque sensor

6 way sensor

7 clutch

8 engine

10 screw foundation

11 helical screw

12 upper flank

13 lower edge

14 cylindrical sleeve

20 soil

21 cavity 30 sleeve

31 mass

32 drive

33 central implementation

34 hollow shaft

35 drive shaft

36 striker

37 drivers

38 wings

39a, b Contact surface pairs v Feed speed (m / min) n Speed screw head (min ¹ ) M Torque (Nm)

U sum of revolutions (1) L distance traveled (m) p thread pitch (m)

s Factor for Slip (1)

N caster

Claims

1. A method for introducing a Schraubfundamentes with a slope on the outer contour having outer spiral in the manner of a thread into the soil, wherein the Schraubfundament during its introduction into the soil alternately or at least temporarily at the same time with a torque and applied in the insertion direction with a striking force.

2. The method of claim 1, wherein on the basis of a rotational speed measurement and longitudinal movement measurement of the screw foundation and the slope, a slip value is determined and the speed changed in such a way and the impact force is switched on or off so that the slip value is kept within predefined limits ,

3. The method of claim 2, wherein the predefined limits are determined as a function of the theoretical penetration rate based on the speed and the thread pitch.

Method according to one of the preceding claims, in which the rotational speed of the

Screw foundation is controlled when screwing in between rated speed and zero revolutions per minute. 5. The method according to any one of the preceding claims, wherein the torque applied to the screw foundation is limited or reduced, in particular when the measured actual torque is equal to a predetermined maximum torque during insertion. 6. The method of claim 5, wherein the impact force is switched on at an abrupt drop in speed.

7. The method according to any one of claims 4 to 6, wherein the speed when reaching the predetermined maximum torque is reduced so far and at the same time the percussion is switched, that the predetermined maximum torque is not exceeded.

8. The method of claim 5 or 6, wherein after limiting or reducing the torque, the impact force is exerted as long on the Schraubfundament until at low torque propulsion in the direction of insertion is present.

9. The method according to any one of claims 4 to 8, wherein the impact force is switched off when reaching the rated speed and torque drop by a predefined value.

10. The method according to any one of claims 1 to 9, wherein when compared to the current speed reduced longitudinal movement, the impact force switched on and the speed is adjusted based on the longitudinal movement and pitch. 11. The method of claim 10, wherein when compared to the reduced longitudinal movement again increased speed, the impact force is turned off.

12. The method according to any one of claims 1 to 11, wherein when compared to a distance along the longitudinal path reduced longitudinal path total of pitch and turns expected longitudinal path the impact force switched on and the speed is reduced so far that the reduced longitudinal path adapted in the direction of the expected longitudinal path becomes.

13. The method of claim 12, wherein upon reaching a predetermined approximate value on the expected longitudinal path, the impact force is switched off.

14. The method according to any one of claims 1 to 13, wherein the impact force is exerted by high-frequency vibrations. 15. The method of claim 14, wherein the high-frequency vibrations are high-frequency or ultra-high-frequency sound vibrations.

16. An apparatus for introducing Schraubfundamenten into the soil, which have a sleeve body and on its outer side an outer spiral having a thread-like pitch, for carrying out the method according to one of claims 1 to 15, which a. a turning device for screwing in the screw foundation, a striking device for generating a striking force in the direction of insertion of the screw foundation,

b. at least one of the following devices from the group comprising a speed measuring device for determining the current rotational speed of the Schraubfundamentes during its introduction, a displacement measuring device for determining the Einbringweges of Schraubfundamentes and means for limiting the torque comprises, and

c. a control device adapted for controlling the rotating device and / or the

Blow device as well as its connection or disconnection on the basis of b. has determined values by means of which the rotating device and the impact device during the introduction are alternately or at least temporarily operated simultaneously.

The apparatus of claim 16, wherein the control device defines the slip value from the current speed, the pitch of the outer coil and the insertion path of the screw foundation, which is compared with a predefined amount of slip value.

Apparatus according to claim 16 or 17, wherein the control device acts on the rotating device as speed-limiting and the impact device switches on when the Schraubfundament strikes a stone or hard ground and the actual Einbringweg is less than the current speed corresponding Einbringweg until the amount of the defined slip value is reached. 19. Device according to one of claims 16 to 18, wherein the impact device is designed as an ultra-high frequency vibrations emitting sound source.

20. Device according to one of claims 16 to 18, wherein the impact device is designed as a high-frequency mechanical vibrations issuing device.

21. Device according to one of claims 16 to 20, in softer on reaching a maximum torque based on a signal provided by a torque sensor, the rotating device is switched off or limits the torque. 22. Device according to one of claims 16 to 21, characterized in that the

Torque from the motor of the rotating device via at least one arranged on a diameter contact surface pair whose contact surfaces are relatively movable relative to a drive shaft and the screw foundation, wherein the diameter corresponds to at least twice, in particular five times the diameter of the drive shaft.