Patent ID: 12215478

DETAILED DESCRIPTION OF SOME EXAMPLE EMBODIMENTS

Use of ordinal terms such as “first,” “second,” “third,” etc., in the claims and description to modify a described feature does not by itself connote any priority, precedence, or order of one described feature over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one described feature having a certain name from another described feature having a same name (but for use of the ordinal term) to distinguish the described feature.

The verbs “to comprise” and “to include” are used in this document as open limitations that neither exclude nor require the existence of un-recited features. The features recited in dependent claims are mutually freely combinable unless otherwise explicitly stated. Furthermore, it is to be understood that the use of “a” or “an”, i.e. a singular form, throughout this document does not exclude a plurality.

In this document, the word “geometric” when used as a prefix means a geometric concept that is not necessarily a part of any physical object. The geometric concept can be for example a geometric point, a straight or curved geometric line, a geometric plane, a non-planar geometric surface, a geometric space, or any other geometric entity that is zero, one, two, or three dimensional.

There is provided ram block arrangements and piling hammers for moving a ram block by an electric machine. The electric machine may generate a magnetic force that is employed for moving the ram block. On the other hand torque of the electric machine may be transformed into linear movement that is communicated to the ram block. The ram block may comprise a frame arrangement for enclosing one or more ram weights therein. The ram block may be configured movable by a magnetic force generated by a linear electric machine (LEM) or by the linear movement transformed from torque of the electric machine. In this way the ram block may be used for driving piles without a hydraulic system for moving the ram block, whereby energy efficiency of piling may be improved. Since the piles are driven without a hydraulic system, also the drawbacks of hydraulic systems are avoided. One approach for configuring the ram block movable by a magnetic force is to provide a connector that enables the ram block to be connected to the linear electric machine. According to this approach the connector is configured to connect the ram block to a mover of the linear electric machine. Thanks to the mover being connected directly to the ram block by the connector, power of the linear electric machine is coupled directly without intermediary gear or transmission to the ram block, whereby a linear movement of the mover may be directly coupled to the ram block. In this way power of the linear electric machine may be efficiently transferred to a movement of the ram block for striking the pile. It should be noted that since there is no need for gears or transmission between the linear electric machine and the ram block, downtime due to service need of such gears or transmission may be avoided which supports operational efficiency of the piling hammer. Another approach for configuring the ram block movable by a magnetic force is to adapt a frame arrangement of the ram block such that the ram block itself can form a part, e.g. a mover, of the linear electric machine. According to this approach the frame arrangement comprises permanent magnets provided one after another in a striking direction of the piling hammer and the frame arrangement is configured movable at least partly inside the linear electric machine. In this approach a need for a connector between the ram block and a mover of the linear electric machine has been eliminated. The resulting piling hammer has a compact structure since the ram block forms a part of the linear electric machine. Accordingly, designing piling hammers based on this approach makes it possible to at least partially decrease the length of the piling hammer compared with the first approach, where the linear electric machine is separated from the ram block by the connector. In an approach for configuring the ram block movable by the linear movement transformed from torque of the electric machine, there is provided an eccentric drive unit that is connected to an output shaft of the electric machine for receiving torque of the electric machine. The rotational movement of the output shaft is transformed into a linear movement, e.g. a movement in a striking direction of the piling hammer, by the eccentric drive unit. A mover is connected to the eccentric drive unit to be linearly movable based on the received torque. The mover is connected to a connector at the ram block, whereby the ram block may be moved by the mover for striking the pile. In this way power of the electric machine is coupled to the ram block.

In an example for understanding the approaches, it should be appreciated that a linear electric machine may comprise a mover comprising an active part containing permanent magnets provided one after another in the longitudinal direction of the linear electric machine, a stator comprising a ferromagnetic core-structure and windings for conducting electric currents. When electric currents are supplied to the windings, a magnetic force acting on the mover is generated, whereby the mover may be moved along a linear path of movement, e.g. back and forth. The mover may be an elongated part that is moved by the magnetic force in a longitudinal direction of the mover.

In another example for understanding the approaches, it should be appreciated that instead of a linear electric machine, also an electric machine having an output shaft for providing a torque as output may be utilized for moving a mover along a linear path of movement. An eccentric drive unit that may be connected to an output shaft of the electric machine for receiving torque and an eccentric drive unit may be connected to the output shaft for transforming the torque into a linear movement. The mover may be connected to the eccentric drive unit, whereby the mover may be moved along the linear path of movement.

In a further example for understanding the approaches, it should be appreciated that the linear electric machine may comprise first and second support structures on both sides of the ferromagnetic core structure of the stator in the longitudinal direction of the mover, the first and second support structures supporting the mover to be linearly movable with respect to the stator in the longitudinal direction of the linear electric machine.

In a further example for understanding the approaches, it should be appreciated that the above-mentioned active part of the mover may be longer than the ferromagnetic core-structure of the stator in the longitudinal direction of the linear electric machine, and the first support structure may comprise a frame-portion made of solid metal, e.g. solid steel. The first support structure may further comprise a support element arranged to keep the mover a distance away from the solid metal of the frame-portion and comprising a sliding surface being against the mover. The support element may comprise material whose electrical conductivity, S/m, is less than that of the solid metal of the frame-portion, e.g. at most half of the electrical conductivity of the solid metal. The support element may be tubular and arranged to surround an end-portion of the mover, the end-portion surrounded by the support element comprising an end-surface of the mover. As the mover is kept the above-mentioned distance away from the solid metal of the frame-portion of the first support structure, eddy currents induced by the permanent magnets of the mover to the solid metal are reduced. Therefore, losses of the linear electric machine are reduced and thereby the efficiency of the linear electric machine is improved.

In a further example for understanding the approaches, it should be appreciated that the linear electric machine can be, for example but not necessarily, a tubular linear electric machine where the ferromagnetic core-structure of the stator is arranged to surround the mover and the windings of the stator are arranged to surround the mover and conduct electric currents in a circumferential direction.

In a further example for understanding the approaches, it should be appreciated that the linear electric machine, or electric machine, may be an electric motor, such as a synchronous motor, such as a flux switching permanent magnet synchronous machine (FSPMSM), or an induction motor.

FIGS.1a,1band2illustrate examples of piling hammers in accordance with at least some embodiments. The piling hammers are illustrated with the help of a striking direction140of the piling hammer and a transverse direction142of the striking direction. Transverse direction of the striking direction may be also referred to a radial direction of a mover112of a linear electric machine108, or an axial direction of a rotatable output shaft129of an electric machine128. In the illustrated examples, the linear electric machine is an induction motor, but it should be noted that the linear electric machine108and the electric machine128may also be a synchronous motors, e.g. FSPMSM. Each of the piling hammers comprise a frame102,122,132a drive cap103attached to the frame and a ram block104,134,124. In order to drive a pile to the ground the ram block is moved reciprocally in the striking direction, e.g. repeatedly up and down. Accordingly, the ram block has along the striking direction one or more upper positions and a lower position at the drive cap. A single blow may start at an upper position, where the ram block has potential energy. In order to drive the pile, the ram block is accelerated from the upper position to the lower position, where the potential energy is transformed into kinetic energy and the ram block strikes the drive cap. The energy from the blow to the drive cap is transferred by the drive cap to the pile for driving the pile deeper into the ground. After the blow, the ram block is returned an upper position for a subsequent blow.

The piling hammers100a,100b,100ccomprise ram block arrangements that comprise ram blocks104,134,124, that comprise frame arrangements106,136for enclosing one or more ram weights therein. The ram blocks104,134,124are configured movable by electric motors. The ram blocks104,134are configured movable by a magnetic force generated by the linear electric machine108and the ram block124is configured movable by torque from the output shaft129of the electric machine128. Using the linear electric machine and the torque of the electric machine128to move the ram blocks104,134,124provides overcoming the drawbacks of the hydraulic piling hammers. The electric machines provide that the acceleration of the ram blocks104,134,124when hitting a pile may be increased compared with hydraulic hammers which is particularly advantageous for tilted processing where less potential energy is converted to kinetic energy.

InFIG.1athe piling hammer100acomprises a linear electric machine108connected to the ram block104of the ram block arrangement. In this way the ram block may be linearly moved by the linear electric machine for driving piles. In an example, the linear electric machine comprises a mover112that is connected to the ram block. A magnetic force generated by a stator of the linear electric machine may be directed to the mover112for causing linear movement of the mover112and the connected ram block. It should be noted that range of linear movement of the mover should be maintained within a range of a magnetic force from the stator for controlling the movement. In an example, the linear electric machine108comprises permanent magnets107,105provided one after another in a striking direction140of the piling hammer100aand a stator comprising windings109for directing a magnetic force to the mover.

In an example in accordance with at least some embodiments the ram block arrangement of the piling hammer100acomprises a connector110configured to connect the ram block104to the mover112of the linear electric machine108. It should be noted that the connector110may be connected to the frame arrangement106at a position, where the mover112, the ram block and the connector110are aligned in the striking direction140of the piling hammer. For example, the mover, the ram block and the connector110are aligned, when they are positioned on a common axis. The common axis may extend along longitudinal directions of each of the mover, the ram block and the connector.

In an example in accordance with at least some embodiments, the connector110comprises a collar portion114adapted to a diameter117of the mover112for connecting the collar portion around a circumference of the mover. In this way the magnetic force directed to the mover may be transformed into a movement of the ram block104via the collar portion connected to the mover. It should be noted that the collar portion may be designed to have a contact surface of a sufficient size with the mover for achieving a desired connecting force with the mover. Therefore, the diameter117of the mover at an end of the mover facing the ram block may be kept relatively small, while securely connecting to the ram block via the collar portion connected at the circumferential surface. It should be noted that since the collar portion is connected to the mover at the circumferential surface, the collar portion may leave the end of the mover facing the ram block substantially uncovered and visible, when the collar portion is connected to the mover. This allows inspecting a condition of the end surface without removing the collar portion. In an example, the collar portion may be connected around the circumference of the mover by a threading. In an example of the threading, the collar portion may have an inside thread and the mover may have an outside thread. In an example, the collar portion may have a shape that provides that the collar portion may be placed around the circumference of the mover. The shape may be circular, e.g. a ring-like shape.

It should be noted that the diameter117and shape of the mover112may be significantly determined based on the linear electric machine108. For example, the diameter of the mover, e.g. at the end of the mover facing the ram block104, may be a cross-sectional diameter in a transverse direction to the longitudinal direction of the mover. The shape of the mover may be an elongated shape having a circular, or ring-like, cross-section. The diameter and shape may be defined based on a diameter and shape of a passage through the stator of the linear electric machine. The passage provides that the mover may reciprocate along a linear path between positions. In one of the positions, a larger portion of the mover is inside of the linear electric machine and in another position a smaller portion of the mover is inside the linear electric machine. The diameter and shape of the passage and the diameter and shape of the mover are preferably made to match to allow movement of the mover in the striking direction140and for efficient transfer of the magnetic force from the stator to the mover in different positions of the mover.

InFIG.1bthe piling hammer100ccomprises an electric machine128comprising a rotatable output shaft129for output of torque. The electric machine128is operatively connected to a ram block124of the ram block arrangement by an eccentric drive unit130. The eccentric drive unit130is connected to the output shaft of the electric machine128and to a mover152for transforming torque from the output shaft into a linear movement of the mover. The ram block arrangement of the piling hammer100ccomprises a connector110configured to connect the ram block124to the mover152of the electric machine128. In this way torque from the output shaft may be transformed into linear movement of the mover for striking the pile. Accordingly, Similar toFIG.1aalso inFIG.1b, the mover152may be an elongated part that is moved by the electric machine. The mover152may be similar to the mover112, however, it should be noted that at least part of the features described with the mover112may be omitted. For example, the permanent magnets105,107may be omitted for the mover152. Also, it should be noted that the mover152may be shorter than the mover112, since the mover152is not inside the electric machine128.

In an example the eccentric drive unit130is configured to be connected to the output shaft of the electric machine128and to the mover152and to transform torque from the output shaft into a linear movement of the mover. One end of the mover may be connected to the connector and another end, i.e. opposite end, to the mover is connected to the eccentric drive unit130.

InFIG.2, the piling hammer100bcomprises a frame122housing the ram block arrangement. The frame122comprises windings111for producing a magnetic force directed to the ram block134in response to electric current supplied to the windings. The magnetic force may be controlled for causing a linear movement of the ram block134in the striking direction140of the piling hammer100b. Accordingly, the frame122of the piling hammer100bis configured to serve as a stator of the linear electric machine and the ram block134of the piling hammer100bis configured to serve as a mover of the linear electric machine.

In an example in accordance with at least some embodiments, the frame arrangement136comprises permanent magnets137,138provided one after another in a striking direction140of the piling hammer100b. In this way the ram block134may serve for a mover of the linear electric machine. It should be noted that range of linear movement of the mover should be maintained within a range of a magnetic force from the stator for controlling the movement.

In an example in accordance with at least some embodiments, neighboring permanent magnets137,138in the striking direction140have opposite magnetization directions. The opposite magnetization directions are illustrated by arrows on the permanent magnets. In this way, when the mover is subjected to the magnetic force from the stator, the linear movement of the ram block134in the striking direction may be facilitated. The magnetization directions of the permanent magnets may be e.g. parallel to the striking direction140.

In an example in accordance with at least some embodiments, the frame arrangement136comprises ferromagnetic core-elements that are alternately with the permanent magnets137,138in the striking direction140of the piling hammer100b. In this way magnetic field density between the permanent magnets may be supported.

FIG.3illustrates an example of a connector configured to connect to a mover of an electric machine in accordance with at least some embodiments. The connector302may be used for the connector110inFIG.1and is described with reference to the items described withFIG.1. The connector302has a base portion116configured to connect with the frame arrangement106and an intermediate portion118for connecting the collar portion114and the base portion116together.

The base portion provides adaptation of the ram block104to the intermediate portion and the collar portion provides adaptation of the mover112to the intermediate portion, whereby in the event of a breakage of either the base portion or the collar portion it may be sufficient to service only the one that is broken without disconnecting the one that is not broken. It should be noted that in the illustrated example the intermediate portion and is shown as connected to the collar portion.

In an example, the collar portion114may comprise a flange120for connecting with the intermediate portion118. The flange provides that the collar portion may be attached by the flange to the intermediate portion positioned towards the ram block104in the striking direction140. In an example, the flange may extend in the transverse direction142.

In an example in accordance with at least some embodiments, the base portion116comprises a lifting lug and the intermediate portion118comprises a lifting eye connectable with the lifting lug by a pin126. The lifting lug and lifting eye provide that the connection between the ram block104and the mover can be quickly secured by placing the pin through the lifting eyer and lifting lug, or quickly released by removing the pin.

In an example according to at least some embodiments, the ram block104,134is a modular ram block. The modular ram block is configured to support adding and removing one or more ram modules for adapting weight of the ram block. Adapting the weight of the ram block provides that energy for striking piles from potential energy of the ram block may be adapted. A low number of ram modules may have a relatively low weight, whereby a contribution of the linear electric machine to a total energy for striking a pile may be larger than if a higher number of ram modules, and a relatively high weight of the ram block, is used for striking the pile.

Examples in accordance with at least embodiments described with reference toFIGS.4a-4c,5and6refer to a linear electric machine400that may be used in the piling hammers100adescribed withFIG.1. However, it should be noted that the linear electric machine400described with reference toFIGS.4a-4c,5and6may also be applied to the linear electric machine described withFIG.2, where the linear electric machine is formed by the ram block134serving as a mover and the frame122serving as a stator of the linear electric machine.

FIG.4ashows a section view of the linear electric machine400according to an exemplifying and non-limiting embodiment. The section plane is parallel with the yz-plane of a coordinate system499comprising x, z, and y axes.FIG.4bshows a magnification of a part480ofFIG.4a, andFIG.4cshows a magnification of a part481ofFIG.4a. The linear electric machine comprises a mover401and a stator405.FIG.4ashows a part of the mover401also separately for the sake of clarity. The mover401comprises an active part402that contains permanent magnets provided one after another in the longitudinal direction of the linear electric machine. The longitudinal direction is parallel with the z-axis of the coordinate system499. InFIGS.4aand4b, two of the permanent magnets are denoted with references403and404.

The stator405comprises a ferromagnetic core-structure and windings for generating magnetic force acting on the mover401in response to supplying electric currents to the windings. InFIG.4b, the ferromagnetic core-structure of the stator is denoted with a reference406and cross-sections of two coils of the windings are denoted with a reference407. As shown inFIG.4b, the ferromagnetic core-structure406constitutes stator slots for the coils of the windings. Typically, the windings are arranged to constitute a multi-phase winding, e.g. a three-phase winding, and the windings can be implemented for example so that each stator slot contains only one coil which belongs to one phase of the windings. It is, however, also possible that each stator slot contains for example two coils which can belong to different phases of the windings or to a same phase of the windings. The linear electric machine400comprises first and second support structures408and409on both sides of the ferromagnetic core-structure of the stator in the longitudinal direction of the linear electric machine. The first and second support structures408and409are arranged to support the mover401to be linearly movable with respect to the stator405in the longitudinal direction of the linear electric machine. As shown inFIG.4a, the active part402of the mover401is longer than the ferromagnetic core-structure of the stator405in the longitudinal direction of the linear electric machine. Thus, during a reciprocating linear movement of the mover401, some of the permanent magnets of the mover401are temporarily inside a frame-portion410of the support structure408. The frame-portion410is made of solid metal, e.g. solid steel, to achieve a sufficient mechanical strength. The support structure408further comprises a support element411arranged to keep the mover401a distance away from the solid metal of the frame-portion410.

InFIG.4c, the above-mentioned distance is denoted with D. The support element411constitutes a sliding surface412that is against the mover and supports the mover401in transversal directions, i.e. in directions perpendicular to the longitudinal direction of the linear electric machine. The support element411comprises material whose electrical conductivity, S/m, is less than that of the solid metal of the frame-portion410. The electrical conductivity of the material of the support element411can be e.g. less than 50%, 40%, 30%, 20%, 10%, or 5% of the electrical conductivity of the solid metal of the frame-portion410. As the mover401is kept the distance D away from the solid metal of the frame-portion410, eddy currents induced by the moving permanent magnets of the mover to the solid metal are reduced. As a corollary, losses of the linear electric machine are reduced and thereby the efficiency of the linear electric machine is improved. The distance D can be e.g. at least 5 mm, at least 10 mm, at least 15 mm, at least 20 mm, at least 25 mm, or at least 30 mm.

The support element411may comprise for example polymer material or some other suitable material having low electrical conductivity and suitable mechanical properties. The polymer material can be e.g. polytetrafluoroethylene, known as Teflon. In a linear electric machine according to an exemplifying and non-limiting embodiment, the support element411comprises a coating constituting the sliding surface that is against the mover401. InFIG.4c, the coating is denoted with a reference415. The coating improves the wear resistance of the sliding surface of the support element411. The coating can be for example a layer of chrome. In cases, where the coating is made of electrically conductive material, the coating is advantageously thin to reduce eddy current losses in the coating. InFIG.4c, the thickness of the coating415is exaggerated for the sake of clarity.

The exemplifying linear electric machine illustrated inFIGS.4a-4cis a tubular linear electric machine where the ferromagnetic core-structure406of the stator405is arranged to surround the mover401and the windings407of the stator are arranged to surround the mover401and conduct electric currents in a circumferential direction. The mover401can be, for example but not necessarily, substantially rotationally symmetric with respect to a geometric line417shown inFIG.4b. The mover401comprises ferromagnetic core-elements that are alternately with the permanent magnets in the longitudinal direction of the mover. InFIG.4b, two of the ferromagnetic core-elements of the mover401are denoted with a reference418. In this exemplifying case, the magnetization directions of the permanent magnets of the mover401are parallel with the longitudinal direction, and longitudinally neighboring ones of the permanent magnets have magnetization directions opposite to each other. InFIG.4b, the magnetization directions of the permanent magnets are depicted with arrows. Exemplifying magnetic flux lines are denoted with curved dashed lines. In this exemplifying case, the mover401comprises a center rod416that mechanically supports the permanent magnets and the ferromagnetic core-elements of the mover. The center rod416is advantageously made of non-ferromagnetic material in order that as much as possible of the magnetic fluxes generated by the permanent magnets of the mover401would flow via the stator405. The center rod416can be made of for example austenitic steel or some other sufficiently strong non-ferromagnetic material.

It should be noted that, the configuration of the active part402and the stator, e.g. in terms of a number of ferromagnetic core elements, a number of permanent magnets and a number of windings and a length of the active part, may adapted according to implementation so as to accelerate a ram block from an upper position to a lower position, where potential energy is transformed into kinetic energy and the ram block strikes a drive cap.

In the exemplifying linear electric machine illustrated inFIGS.4a-4c, the support element411is tubular and arranged to surround an end-portion413of the mover401. An end-portion414of the support structure408may be closed.

FIG.5shows a section view of a part of a linear electric machine according to an exemplifying and non-limiting embodiment. The part is described with reference to items described withFIGS.4a-4c. The section plane is parallel with the yz-plane of a coordinate system599comprising x, z, and y axes.FIG.5illustrates a part of a support structure508of the linear electric machine and a part of a mover501of the linear electric machine. The support structure508is arranged to support the mover501in the same way as the support structure408is arranged to support the mover401in the linear electric machine400illustrated inFIGS.4a-4c. The support structure508comprises a support element511that comprises material whose electrical conductivity is less than that of solid metal constituting a frame-portion510of the support structure508. In this exemplifying linear electric machine, the support element511comprises ferromagnetic material519whose electrical conductivity is less than that the solid metal constituting the frame-portion510, e.g. at most half of the electrical conductivity of the solid metal. The ferromagnetic material519provides low reluctance paths for magnetic fluxes generated by permanent magnets of the mover501, and thereby the ferromagnetic material519reduces magnetic stray fluxes directed to the frame-portion510of the support structure508. Furthermore, the ferromagnetic material519reduces the flux variation taking place in the permanent magnets and thereby the ferromagnetic material reduces losses of the permanent magnets. The ferromagnetic material519can be for example ferrite or iron powder composite such as e.g. SOMALOY® Soft Magnetic Composite. The support element511further comprises a coating515on a surface of the ferromagnetic material and constituting a sliding surface that is against the mover501. The coating515can be for example a layer of chrome.

FIGS.6a,6band6cshow block diagrams for hammer devices650,652,654according to at least some embodiments. All the hammer devices comprise electric machines. The hammer devices shown inFIGS.6aand6bcomprise linear electric machines690,692and, with reference to bothFIGS.6cand1b,FIG.6cshows an electric machine694comprising an output shaft129connected to an eccentric drive unit130for transforming a rotation of the output shaft into a linear movement of a mover152connected to the eccentric drive unit. The hammer devices comprise processors connected to the electric machines690,692,694. The processor is configured to perform one or more functionalities described in examples herein. The processor may be included in a control device620,622,624, e.g. an electric motor controller (EMC). The control device may comprise a memory and computer program comprising instructions that, when executed by the processor cause to perform one or more functionalities described in examples herein, e.g. at least for accelerating a mover of the hammer device for striking a pile.

As a difference to the linear electric machine690of the hammer device650, the linear electric machine692of the hammer device652may be used for regenerative braking and electrical current of the regenerative braking may be stored to an energy storage as controlled by a control device622of the hammer device. Accordingly, it should be noted that the linear electric machine692of the hammer device652may be used at least for decelerating a mover of a hammer device and additionally for accelerating the mover of the hammer device.

The hammer device650,652,654inFIGS.6a,6band6cmay be a hammer for a ram pile, or a piling hammer for striking a pile610, e.g. as described with reference toFIGS.1and2. A piling hammer is a machine used in construction work for driving steel, concrete, or wood piling into the earth by a reciprocating movement of a hammer block. The section plane is parallel with the yz-plane of a coordinate system699comprising x, z, and y axes. The hammer device may comprise a frame arrangement630that may comprise one or more elements, e.g. guides such as leader guides, for connecting the hammer device to a leader of a pile driving machine. The hammer device650,652comprises a linear electric machine690,692and a ram block632connected to a mover of the linear electric machine. The hammer device654comprises an electric machine694comprising an output shaft129connected to an eccentric drive unit696for transforming a rotation of the output shaft into a linear movement of the mover152that is connected to the eccentric drive unit and a ram block632. Therefore, in all the hammer devices650,652,654the mover is linearly movable, e.g. movable in the striking direction, by the electric machine. The piling hammer comprises an electric motor controller (EMC), or a control device,620,622,624for controlling the linear electric machine690,692or the electric machine694. In an example the EMC may be connected to the linear electric machine690,692, or the electric machine694, and/or an external power supply for supplying electric currents to windings of the linear electric machine, or the electric machine694, for controlling a linear movement of a mover of the linear electric machine, or a linear movement of a mover connected to the eccentric drive unit. The controlling of the linear movement of the mover may comprise accelerating or decelerating the mover. The linear movement may be a reciprocating movement in a direction parallel to the z-axis. Therefore, when connected to the mover, the ram block is linearly movable with the mover, whereby both the mover and the ram block may be moved in the same direction parallel to the z-axis. It should be noted that the z-axis may be a vertical direction on a direction inclined with respect to the vertical direction. The frame arrangement may comprise guides for supporting movement of the ram block and the mover in a direction inclined with respect to the vertical direction.

In an example, the electric motor controller (EMC), or the control device,620,622,624may be connected to a power electronic converter, or the power electronic converter may serve as the electric motor controller (EMC), or the control device,620,622. The power electronic converter may be coupled to the windings of the stator of the linear electric machine690,692, or the stator of the electric machine694.

The hammer device650,652,654may comprise a drive cap670for transferring a striking force from the ram block to a pile for driving the pile by the piling hammer. The drive cap may be constructed within a drive cap housing comprising a drive cap cushion and a rebound ring. The drive cap may have on its lower side a plurality of surfaces against which the pile610can fit. When striking the pile, the energy from the ram block striking the drive cap may be transferred to the pile through the drive cap that sits on top of the pile. The mover and therewith the ram block may be engaged in a reciprocating movement for continuously driving the pile by striking the pile by consecutive blows of the ram block. The linear electric machine690,692can be for example such as illustrated in any ofFIGS.1a,2,4a-4corFIG.5.

In an example, the piling hammer650,652,654may be configured to determine a position of the mover and/or the ram block632. The position of the mover and/or the ram block632may be determined based on electrical induction, e.g. by the control device620,622624. The electrical induction may be measured by the control device connected to the LEM and/or one or more sensors640, e.g. inductive sensors. The control device may measure electrical current induced to the windings of the LEM. Accordingly, a movement of the mover induces electrical currents to the windings, which may be measured by the control device. The windings are arranged to the stator both radially around the mover and axially, parallel to the longitudinal direction of the mover, e.g. parallel to the z-axis, whereby the position of the mover may be determined based on the electrical induction of electrical current to the windings as the mover is moved linearly back and forth through the stator that holds the windings. On the other hand, the one or more sensors640may be arranged to the piling hammer650,652,654for detecting a position of the mover and/or the ram block632. The one or more sensors640may be arranged e.g. to the frame arrangement630, e.g. to detect one or more upper positions and/or one or more lower positions of the mover. Examples of the one or more sensors comprise at least a mechanical position sensor comprising a sensor rod fixed to the mover of the electric machine. The position of the mover can also be measured in a contactless way, for example with a laser measurement arrangement. It is also possible provide the mover and the stator with structures operable as an inductive position sensor. The mover and the ram block may be directly connected to each other, whereby they may be moved as a single entity. Therefore, detecting a position of the mover or the ram block may be used to determine a position of the other. Examples of the detected positions at least a peak position and a position of the pile head. The peak position may be the highest position of the ram block632for striking the pile at a total target kinetic energy. After the blow to the pile by the ram block, the pile may advance and the ram block is recoiled upwards, e.g. in a direction parallel to the z-direction. The recoiled ram block is stopped at a new peak position for a subsequent blow to the pile. When the pile is advanced, subsequent peak positions of the ram block may form a decreasing series of peak positions. An advancement of the pile may be determined based on a difference between peak positions of subsequent blows or peak positions between a number of blows.

In an example, the piling hammer652may comprise an energy harvesting system680for harvesting at least a part of recoiled kinetic energy from striking the pile610using a ram block connected to a mover of the linear electric machine692. The energy harvesting system may comprise an energy storage for example an electrical battery. The energy harvesting system may be connected to the linear electric machine692for receiving electrical current from the linear electric machine, when the linear electric machine is performing regenerative braking. When the linear electric machine is performing regenerative braking, the linear electric machine is operating as a generator of electric current for decelerating a movement of the mover. The electrical current from the linear electric machine is stored to the energy storage. The energy harvesting system may be connected to supply electrical current from the energy storage to the linear electric machine, when the linear electric machine is operating as electric motor. In this way the electrical energy stored to the energy storage may be used to accelerate the mover. The control device622may be connected to the energy storage and the linear electric machine for controlling the linear electric machine and flow of electric current between the linear electric machine and the energy storage.

The hammer device650,652,654may comprise a power supply. The control device may be included to a power supply or the power supply may be an external power supply. When the hammer device is installed to a pile driving apparatus, the power supply may be deployed to the pile driving apparatus. In a similar manner, the energy storage680may be built-in to the hammer device or the energy storage may be external to the hammer device. When the hammer device is installed to a pile driving apparatus, the energy storage may be deployed to the pile driving apparatus.

FIG.7illustrates an example of a pile driving apparatus according to at least some embodiments. The pile driving apparatus may comprise a piling hammer described in accordance with an example described herein. The pile driving apparatus702comprises a leader704and a piling hammer706installed to the leader. The leader is an elongated part of the pile driving apparatus, having the function of enabling a movement of the piling hammer in a direction that is transverse or inclined with respect to the ground surface708during driving a pile710into the ground. The leader may be tilted for driving the pile in a vertical or an inclined position and for tilting the leader to a horizontal position for the time of transport of the pile driving machine.

FIG.8illustrates a part of a linear electric machine in accordance with at least some embodiments. The linear electric machine800may be used in the piling hammer100adescribed withFIG.1. However, it should be noted that the linear electric machine800may also be applied to the linear electric machine described withFIG.2, where the linear electric machine800is formed by the ram block134serving as a mover and the frame122serving as a stator of the linear electric machine800.

The linear electric machine800comprises a mover804and a stator805. The mover804is movably supported relative to the stator805, the direction of movement of the mover804being parallel to the z-axis of a coordinate system899.FIG.8shows a section view in which the section plane is parallel to yz-plane of the coordinate system899. The stator805comprises windings for generating a magnetic force directed to the mover804in response to electric current supplied to the windings. In the exemplifying case shown inFIG.8, the windings constitute a three-phase winding whose phases are denoted with figure references U, V and W. The linear electric machine is a tubular linear electric machine in which the conductor coils of the stator windings are arranged to surround the mover804. The mover804and the electromagnetically active parts of the stator805can be, for instance, rotationally symmetric with respect to a geometric line820shown inFIG.8. InFIG.8, the cross-sections of the conductor coils of the windings of the stator805are presented as cross-hatched areas.FIG.8uses a notation in which the left side of an area representing a cross-section of each conductor coil is provided with a phase-indicating figure reference U, V or W, and with “+” if the direction of electric current in the conductor coil cross-section under consideration is the positive x-direction of the coordinate system899when the electric current of this phase U, V or W is positive, or with “−” if the direction of the electric current in the conductor coil cross-section under consideration is the negative x-direction of the coordinate system899when the electric current of this phase U, V or W is positive. The stator805has annular permanent magnets provided one after another in the longitudinal direction of the mover804, wherein the axial direction of the annular shape of each permanent magnet coincides with the longitudinal direction of the mover, i.e. is parallel with the z-axis of the coordinate system899. InFIG.8, two of the annular permanent magnets are denoted with figure references807and808. The magnetizing directions of the permanent magnets coincide with the longitudinal direction of the mover804, the magnetizing directions of the successive permanent magnets being opposite to each other. The magnetizing directions of the permanent magnets are indicated with arrows inFIG.8. An exemplifying magnetic flux line is depicted with a dashed line. The core structure of the stator805comprises annular ferromagnetic elements surrounding the mover804and forming slots for the conductor coils of the windings. InFIG.8, two of the annular ferromagnetic elements are denoted with figure references809and810. The annular ferromagnetic elements and the permanent magnets of the stator are provided in the longitudinal direction of the mover804so that there is one of the slots between successive permanent magnets. In this exemplifying case, two conductor coils are provided in each stator slot. For example, conductor coils with designations +V and −W are provided in the slot formed by the ferromagnetic elements809and810. The stator805may also comprise a stator frame817, possibly equipped with cooling channels for a cooling medium flow. The stator frame817is advantageously made of a non-ferromagnetic material to allow a portion as large possible of the magnetic flux generated by the permanent magnets to travel through the mover804. The stator frame817can be made of for example aluminum.

The mover804has a center rod811and annular ferromagnetic elements provided around the center rod to form a ferromagnetic core structure of the mover. InFIG.8, two of the annular ferromagnetic elements of the mover are denoted with figure references812and813. The annular elements of the mover804are shaped to form, on the outer surface of the mover, ridges oriented in the circumferential direction of the mover and causing a reluctance variation which enables the stator805to generate the magnetic force directed to the mover.FIG.8only shows a portion of the linear electric machine concerned. In total, the slots of the stator805can be for example 12 in number, for example, and the ridges can be provided on the mover804so that there are for example 13 mover ridges in the area covered by the stator. The mover804must have such a length that there is a sufficient number of ridges in the area covered by the stator within the entire range of movement of the mover. It should be noted that, the number of slots and ridges as well as the length of the mover may adapted according to implementation so as to accelerate a ram block from an upper position to a lower position, where potential energy is transformed into kinetic energy and the ram block strikes a drive cap.

The linear electric machine illustrated inFIG.8, having permanent magnets on its stator, is often referred to by the term a Flux switching permanent magnet synchronous machine, abbreviated as “FSPMSM”.

It should be noted that an electric machine for a ram block arrangement and piling hammer in accordance with at least some embodiments may be implemented in various ways. For example, the electric machine may be a linear electric machine and formed by a ram block serving as a mover and a frame serving as a stator of the linear electric machine in accordance withFIG.2. On the other hand, the linear electric machine may have a stator and a mover connected by a connector to the ram block in accordance withFIG.1. Depending on the implementation of the linear electric machine, the mover or the ram block serving as the mover may be provided with permanent magnets of the permanent magnets may be omitted. In the latter case the permanent magnets may be provided at the frame or included to the frame of the ram block together with stator windings and ferromagnetic elements. Accordingly, the frame of the ram block arrangement may be a stator frame, a stator frame may be connected to the frame of the ram block arrangement. In the latter case, the stator frame may be connected inside the frame of the ram block arrangement, whereby it is protected by the frame of the ram block arrangement and efficient travel of the magnetic flux generated by the permanent magnets through the ram block serving as the mover may be supported.

It is to be understood that the embodiments disclosed are not limited to the particular structures, process steps, or materials disclosed herein, but are extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting.

Reference throughout this specification to one embodiment or an embodiment means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in/according to one embodiment” or “in/according to an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Where reference is made to a numerical value using a term such as, for example, about or substantially, the exact numerical value is also disclosed.

As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience.

However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. In addition, various embodiments and examples may be referred to herein along with alternatives for the various components thereof. It is understood that such embodiments, examples, and alternatives are not to be construed as de facto equivalents of one another, but are to be considered as separate and autonomous representations.

The foregoing description has provided by way of exemplary and non-limiting examples a full and informative description of the exemplary embodiment of this invention. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended examples. However, all such and similar modifications of the teachings of this invention will still fall within the scope of this invention.