Method for cracking a connecting rod

Abstract

The machine for cracking a connecting rod comprises an electro press with an electric motor (400) for actuating an expandable element. The electro press comprises a first S actuator part (410) and a second actuator part (430) arranged so that when the first actuator part is driven by the electric motor (400) from a first position to a second position, (a) the first actuator part (410) is first driven by the electric motor (400) from said first position (FIG. 12A) to an intermediate position (FIG. 12B), without displacing the second actuator part (430), and (b) subsequently the first actuator part (410) is further driven by the electric motor (400) from said intermediate position (FIG. 12B) to said second position (FIG. 12C), displacing the second actuator part from a non-expanding position to an expanding position.

Claims

1. Method of cracking a connecting rod having a small end and a big end, into a rod part (1001) and a cap part (1002), using a machine comprising: positioning elements for positioning said connecting rod in a position for cracking; an expandable element (3) arranged to be inserted into a bore in said big end of the connecting rod so as to allow for splitting of said connecting rod (1000) into said rod part (1001) and said cap part (1002) by expanding said expandable element; and an electro press (4) comprising an electric motor (400) for actuating the expandable element by means of displacing an actuator (410, 430) to expand said expandable element; the method comprising the steps of: operating the electric motor (400) to first accelerate said actuator (410, 430) until it reaches a predetermined velocity before expansion of said expandable element (3), and thereafter maintaining said actuator moving substantially at said predetermined velocity during expansion of said expandable element (3) until the connecting rod has been cracked into said rod part and said cap part.

2. Method according to claim 1, wherein the step of thereafter maintaining said actuator moving substantially at said predetermined velocity is carried out so that said actuator is maintained moving within a range of velocities deviating less than 10% from said predetermined velocity.

3. Method according to claim 2, wherein the step of thereafter maintaining said actuator moving substantially at said predetermined velocity is carried out so that said actuator is maintained moving within a range of velocities deviating less than 5% from said predetermined velocity.

4. Method according to claim 3, wherein the step of thereafter maintaining said actuator moving substantially at said predetermined velocity is carried out so that said actuator is maintained moving within a range of velocities deviating less than 2% from said predetermined velocity.

5. Method according to claim 4, wherein the step of thereafter maintaining said actuator moving substantially at said predetermined velocity is carried out so that said actuator is maintained moving within a range of velocities deviating less than 1% from said predetermined velocity.

6. Method according to claim 2, wherein during the step of thereafter maintaining said actuator moving substantially at said predetermined velocity, the actuator is displaced more than 1 cm and less than 15 cm.

7. Method according to claim 2, wherein the electric motor is a servomotor.

8. Method according to claim 1, wherein during the step of thereafter maintaining said actuator moving substantially at said predetermined velocity, the actuator is displaced more than 1 cm.

9. Method according to claim 8, wherein during the step of thereafter maintaining said actuator moving substantially at said predetermined velocity, the actuator is displaced more than 2 cm.

10. Method according to claim 9, wherein during the step of thereafter maintaining said actuator moving substantially at said predetermined velocity, the actuator is displaced more than 3 cm.

11. Method according to claim 9, wherein during the step of thereafter maintaining said actuator moving substantially at said predetermined velocity, the actuator is displaced less than 15 cm.

12. Method according to claim 8, wherein during the step of thereafter maintaining said actuator moving substantially at said predetermined velocity, the actuator is displaced less than 15 cm.

13. Method according to claim 12, wherein during the step of thereafter maintaining said actuator moving substantially at said predetermined velocity, the actuator is displaced less than 10 cm.

14. Method according to claim 13, wherein during the step of thereafter maintaining said actuator moving substantially at said predetermined velocity, the actuator is displaced less than 8 cm.

15. Method according to claim 14, wherein during the step of thereafter maintaining said actuator moving substantially at said predetermined velocity, the actuator is displaced less than 6 cm.

16. Method according to claim 15, wherein during the step of thereafter maintaining said actuator moving substantially at said predetermined velocity, the actuator is displaced less than 5 cm.

17. Method according to claim 16, wherein during the step of thereafter maintaining said actuator moving substantially at said predetermined velocity, the actuator is displaced less than 4 cm.

18. Method according claim 8, wherein the electric motor is a servomotor.

19. Method according to claim 1, wherein during the step of thereafter maintaining said actuator moving substantially at said predetermined velocity, said actuator is displaced a sufficient distance to make sure that a part of the cracking process including a first and a second fracture, will take place while the actuator is being displaced at substantially the predetermined velocity.

20. Method according to claim 1, wherein the electric motor is a servomotor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description considered in conjunction with the accompanying drawings in which like reference numeral designate like parts throughout the figures thereof and wherein:

(2) FIG. 1 illustrates an example of a connecting rod;

(3) FIGS. 2A and 2B are two top views of a machine according to an embodiment of the invention, without and with a connecting rod to be cracked, respectively;

(4) FIG. 3 is a perspective partial view of the machine of FIGS. 2A and 2B;

(5) FIG. 4 schematically illustrates the first positioning elements;

(6) FIG. 5 is a perspective view of the machine, including the actuator of the expandable element;

(7) FIG. 6 is a lateral view in cross section of a first positioning carriage and associated equipment;

(8) FIG. 7 is a perspective view of a first positioning carriage;

(9) FIGS. 8A and 8B are schematic lateral views in cross section of a first positioning carriage and associated equipment, illustrating how a carriage is blocked into position;

(10) FIG. 9 is a schematic rear view of the part of the machine associated to the first positioning carriages;

(11) FIG. 10 Is a perspective rear view of said part of the machine;

(12) FIG. 11 is a schematic cross sectional view of the machine in accordance with a preferred embodiment of the invention;

(13) FIGS. 12A, 12B, 12C and 12D are schematic perspective views of part of the mechanism for driving the cleaving wedge, at four different stages of the cracking process;

(14) FIG. 13 schematically illustrates the velocity of the first actuator part as a function of time, in accordance with an embodiment of the invention; and

(15) FIG. 14 illustrates the results of a test of a machine in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(16) The present invention can be implemented on the. basis of a machine as described in WO-2013/034782-A1, which will be described below with reference to FIGS. 2A-10, which are identical to those of WO-2013/034782-A1. FIGS. 2A and 2B schematically illustrate this machine, including a basic machine frame including a first, fixed, part 1, in relation to which a second part 2, comprising a first (main) carriage 21, is slidably mounted, between a proximal position and a distal position. The second part 2 further comprises a second carriage 22, which is slidably mounted within the first carriage, so that it can move forwards and backwards within said first carriage 21. An actuator or drive device 25 is provided on the first carriage 21, to controllably displace the second carriage 22 within the first carriage, for example, so as to bias the second carriage against stops 26 in a loading phase of the operation of the machine.

(17) As can be best seen in FIG. 3, a first half-shell or sleeve portion 19 is attached to the first part 1 by screws 190, and a second half-shell or sleeve portion 29 is attached to the first carriage 21 by screws 290. These two sleeve portions 19 and 29 form, when together (that is, when the first carriage is in the proximal position, as illustrated in FIG. 3), a protrusion, which will enter the big bore of the connecting rod 1000 when the rod is mounted in the machine for cracking (as shown in FIG. 2B). These sleeve portions form part of an expanding element 3, which further comprises two expander mandrel halves 31 and 32, positioned within the sleeve or cylinder formed by the first 19 and second 29 sleeve portions. One of these expander mandrel parts 31 is attached to the first part 1 of the machine, and the other expander mandrel part is attached to the first carriage 21. The expander mandrel halves are arranged to be separated by an advancing movement of a cleaving wedge 33. The cleaving wedge can be actuated by any suitable actuation means, such as a conventional hydraulic actuator often used in this kind of machines, although it can sometimes be preferable to use an electro press 4, as schematically illustrated in FIG. 5.

(18) In addition to the sleeve made up by the first 19 and second 29 sleeve portions, there are several further positioning means for positioning the connecting rod in the machine. First positioning means are arranged on the first part 1 and include first positioning elements 11, which are arranged to be displaced forwards and backwards by corresponding actuators housed in the carriages 11A (referred to herein as first positioning carriages), mounted on the first part 1 of the machine. These first positioning elements 11 are arranged to be at least partially inserted into the screw bores of the connecting rod that are used to house the screws that attach the cap part to the rod part after cracking, as schematically illustrated in FIG. 4. These first positioning elements include a spindle part or portion 111 which is inserted into said screw bores from the cap part end of the connecting rod, and a contact surface 110 or abutment portion which, when the positioning elements are brought towards the connecting rod during operation of the machine, abuts against the cap portion of the connecting rod and thus biases it towards the first sleeve portion 19, establishing contact with said first sleeve portion 19. The spindle parts thus become fully inserted into the screw bores. As illustrated in FIG. 4, the spindle parts 111 include fluid outlets 12 and, during operation of the machine, a cleansing fluid can be provided to constantly or intermittently flow out of these outlets 12. These outlets are positioned so that when cracking takes place, fluid from these fluid outlets 12 will impinge on the crack surfaces of the cap part and/or the rod part, so as to help to remove loose particles.

(19) On the other hand, as best shown in FIG. 3, further fluid outlets 13 are provided in the first part 1 and in the first carriage 21, adjacent to the area where the two sleeve parts 19 and 29 meet, so as to provide further fluid to the crack surfaces when cracking take place, so as to help to remove loose particles.

(20) The fluid can be, for example, compressed air.

(21) Further positioning means for positioning the connecting rod for cracking comprise a centering pin 23, arranged to fit into the small bore 1005 of the connecting rod, and two additional positioners 24 arranged to bias the large end of the connecting rod away from the centering pin 23. The centering pin 23 and the additional positioners 24 are arranged on the second carriage 22 which, as explained above, is moveable within the first carriage 21. The purpose of this floating arrangement of the positioning means is to reduce the risk for excessive stresses or forces that may damage or deteriorate the connecting rod during an initial phase of the cracking operation.

(22) In accordance with the present embodiment, when the connecting rod is to be placed in the machine, the second carriage 21 is biased against the stops 26 by the actuator 25, and the connecting rod is inserted into the machine, so that the centering pin 23 enters the small bore of the connecting rod. The centering pin 23 can be displaced towards the first part 1 by external forces, so as to facilitate a correct positioning of the connecting rod, which is placed so that the sleeve 19+29 enters the large bore 1006 of the connecting rod.

(23) Once the connecting rod has been positioned, the first positioning elements 11 are brought forwards (that is, towards the connecting rod), the spindles 111 enter the screw bores, and the contact surfaces 110 abut against the cap portion of the connecting rod, so that the connecting rod is firmly biased against, and in contact with, the first sleeve portion 19; both the actuators of the first positioning elements (housed in the first positioning carriages 11A) and the actuator 25 thus tend to bias the connecting rod towards the first sleeve portion 19. This gives rise to a small separation between the inner surface of the large bore of the connecting rod, and the second sleeve portion 29.

(24) When the cleaving wedge 33 starts to advance, the second sleeve portion 29 is forced to move away from the first sleeve portion 19, towards the small end of the connecting rod; the first carriage 21 on which the second sleeve portion 29 is mounted will likewise move. If the small end of the connecting rod had been fixed to the first carriage 21, tensions would have occurred in the connecting rod, as its large end is prevented from moving by the first sleeve portion 19. However, as the connecting pin 23 is mounted on the second carriage 22, which is floating with regard to the first carriage 21, the connecting rod can maintain its original position without substantial stresses, in spite of this initial movement of the first carriage 21. Thereby, these tensions and stresses do not occur or are, at least, substantially reduced.

(25) Once the second sleeve portion 29 abuts the inner surface of the large bore of the connecting rod, cracking takes place in the normal way, in accordance with notches or similar, previously made by, for example, laser, in a conventional way. After cracking, the rod part and the cap part are separated, and the rod part is carried away from the cap part due to the movement of the first carriage 21.

(26) FIG. 5 schematically illustrates the use of an electro press instead of the conventionally used hydraulic press. The advantages involved have been described above.

(27) In order to adapt the machine to different kinds of connecting rods to be produced, it can be necessary to change the distance between the first positioning elements 11, so as to adapt this distance to the distance between the screw bores at the cap end of the connecting rod to be produced, so that the spindle portions 111 can be inserted into said screw bores or, if the first positioning elements do not include this kind of spindle portions, the contact surface 110 will abut against the big end of the connecting rod at a desired point or area of said big end. In order to facilitate this, the first positioning elements 11 can be placed in first positioning carriages 11A that are arranged laterally displaceable along horizontal guides 11F, as shown in FIG. 6. These guides 11 Fare associated to a fixed part 1A of the machine, which can be fixed with regard to, for example, the first part 1 of the machine. Hand-wheels 11G are mounted to said fixed part 1A for displacing blocking elements 11C used to block the first positioning carriages in selected positions, each of said selected positions corresponding to a predetermined position of the corresponding first positioning element 11. Thus, by placing the first positioning carriages at a selected specific position, the machine can be adapted to manufacture a specific kind of connecting rod, having a specific distance between the screw bores.

(28) FIG. 7 illustrates how a first positioning carriage is provided with a plurality of openings 11B, distributed in the vertical direction. Each of said openings has a specific position also in the lateral or horizontal direction (at a first look, it may seem that the openings 11B are all in the same position along the horizontal axis, but this is only due to the fact that the openings are substantially larger than the difference in their position in the horizontal direction; the difference between the distances of the screw bores of different connecting rods can be rather small, so that the lateral displacement of the first positioning carriages needed for adapting the machine to different kinds of connecting rods is often not very big; however, using fairly large openings 11B can be preferred; for example, it can be preferred that all of the openings overlap with each other by more than 50% when projected—orthogonally—onto the horizontal axis, as this can facilitate insertion of the blocking element when switching from one opening to another, as will be clear from our discussion below).

(29) Thus, by inserting the blocking element 11C into a selected one of said openings 11B, the carriage 11A can be placed in a specific lateral/horizontal position, corresponding to a specific position of the first positioning element. Figure BA shows how the blocking element 11C has been placed at the level of the second opening 11B from above, and by rotating the hand-wheel 11G the blocking element is introduced into this opening, to the position shown in Figure BB, where it fits snugly into said opening 11B, thus blocking the carriage 11A in a certain selected lateral position.

(30) As can be seen in FIGS. 8A and 8B, the blocking element 11C has a conical end. FIG. 7 illustrates how the openings 11B all have a size such that they overlap substantially when projected onto the horizontal axis. That is, when displacing the blocking element 11C in the vertical direction so as to change it from having been inserted into one of these openings to be inserted into another one of these openings, the tip of the blocking element will be in correspondence with the new opening, thereby avoiding the need to “manually” displace the carriage laterally to be able to insert the tip into the corresponding opening. Now, when rotating the handwheel so as to introduce the blocking element into the new opening, due the beveled character of the end and the snug fit between the blocking element 11C and the opening 11B when the blocking element is fully inserted, the advancing movement of the blocking element 11C will displace the carriage 11A laterally to its desired position.

(31) FIGS. 9 and 10 illustrate a vertical guide 11H for the joining structure 11D by which the blocking elements 11C corresponding to the two carriages 11A are joined to each other, together with their associated hand-wheels 11G. This guide is mounted at the rear part of the fixed part 1A of the machine, and includes a plurality of openings 11J, each of said openings corresponding to one of the openings 11B in the carriages 11A. It can be seen how the openings 11B in the carriages 11A are visible from the rear part through the slots 11I through which the blocking elements 11C penetrate (cf. also FIGS. 8A and 8B).

(32) In the position shown in FIG. 9, the blocking elements 11C are associated to the lowermost openings 11B of the two carriages 11A. To change the machine for the manufacture of a connecting rod having a different distance between the screw bores at the cap end, for example, the distance corresponding to the second opening 11G from above, the operator of the machine will first move the hand-wheels 11G so as to withdraw the blocking elements 11C out of the openings 11B. Next, the operator will pull the blocking means 11E backwards, so that a corresponding pin is drawn out of the lowest ones of the openings 11J. Next, the operator will, for example, manually, lift the whole blocking arrangement, including the joining structure 11D, the hand-wheels 11G, and the associated blocking elements 11C, until the pin (not shown) of the blocking means 11E reaches the level of the second opening 11J from above, where the operator will let the pin (such as a spring-loaded pin) snap into this opening. This corresponds to the position of Figure BA. The operator can now simply turn the hand-wheels to introduce the blocking elements 11C into the second openings 11B from above, and during this insertion of the blocking elements into the respective openings 11B, the two carriages 11A are displaced to their new positions, thus positioning the first positioning elements in the correct position for manufacture of the new kind of connecting rod.

(33) Of course, the invention can also be implemented in different kinds of machines, and in variants of the machine discussed with reference to FIGS. 2A-10.

(34) For example, in some variants, the additional positioners 24 are omitted.

(35) FIG. 11 schematically illustrates a cross section of the machine in accordance with an embodiment of the invention, with a connecting rod 1000 being arranged in a position for cracking, and wherein said cracking is produced by displacing the cleaving wedge 33 so as to separate the two expanding mandrel halves 31 and 32, and thus the optional sleeve portions 19 and 29, as explained above. The cleaving wedge 33 is driven by an electric press 4 comprising an electric motor 400, having a vertically oriented output shaft 402 which, through a belt, chain or other suitable transmission means 403, drives a vertically oriented threaded shaft or spindle 401 so that this spindle rotates around its vertical axis. A carriage 412 is connected to a threaded nut 404 or similar so that when the spindle 401 rotates, the carriage 412 is driven upwards or downwards, depending on the direction of the rotation of the spindle 401. A first actuator element 410 is connected to the carriage so that it can be driven between a first position, shown in FIG. 12A, and a second position, shown in FIG. 12C.

(36) On the other hand, the cleaving wedge 33 is a lower end part of a second actuator part 430, said second actuator part having an upper end portion 432 against which the first actuator part collides when it moves down from said first position to said second position, more specifically, when reaching an intermediate position as shown in FIG. 12B.

(37) The first actuator part 410 has an end portion 411 which is arranged to contact said second actuator part when the first actuator part 410 reaches said intermediate position when coming from said first position. Said end portion 411 of said first actuator part 410 is retained within a retaining portion 431 of said second actuator part, basically, within a kind of cage structure comprising vertical members 431A or walls and horizontal retaining members 431B, arranged to prevent the end portion 411 of said first actuator part 410 from being withdrawn from said retaining portion 431. The retaining portion is designed so as to allow a relative movement between said first actuator part 410 and said second actuator part, in the vertical or axial direction, to an extent that corresponds to the distance between said first position and said intermediate position.

(38) A pressure sensor 433 can be included, for example, as part of the second actuator part 430. This pressure sensor can be used to detect variations in the pressure exerted by the second actuator part, and this information can be transmitted to a control unit (not shown in FIG. 11) and used to determine, for example, when the first and second fractures take place and, thus, to verify that the cracking process is performed in the desired manner, for example, with the time between the two fractures being within a desired time interval.

(39) Thus, as shown in FIGS. 12A-12D, the process of cracking a connecting rod can comprise the following steps:

(40) In FIG. 11, the first actuator part 410 is in its first or uppermost position, also shown in FIG. 12A. From here, the electric motor 400 is actuated to rotate the spindle 401 so as to drive the carriage 412 with the first actuator part 410 downwards, accelerating it until reaching a desired speed. Due to the distance X between the opposing ends 411 and 432 of the first and second actuator parts (see FIG. 11), during this step, the second actuator part is not displaced; the first end 411 of the first actuator part merely moves downwards within the retaining structure 431. Thus, the motor can accelerate the first actuator part without having to overcome any force due to displacement of the cleaving wedge 33 which forms part of the second actuator part 430.

(41) In FIG. 12B, the first actuator part 410 has been driven down and accelerated until it reaches the intermediate position, when its end 411 impacts on the upper end 432 of the second actuator part 430. From now on, the electric motor 400 continues to drive the first actuator part 410 downwards and, with it, the second actuator part 430, whereby the cleaving wedge 33 is displaced downwards and separates the mandrel halves 31 and 32, to produce the cracking of the connecting rod. The first actuator part is driven downwards until reaching the second position, schematically illustrated in FIG. 12C.

(42) After cracking, the electric motor is reversed to drive the first actuator part 410 upwards. After moving upward a distance X corresponding to the freedom of movement allowed by the retaining portion 431, the end portion 411 of the first actuator part, which has a larger diameter than the adjacent portion of the first actuator part 410, abuts from below against the horizontal retaining members 431B (as shown in FIG. 12D), thereby pulling the second actuator part 430 upwards, until it reaches its initial position, shown in FIG. 12A. At this state, the cleaving wedge has been withdrawn and returned to the position shown in FIG. 12A, and a new connecting rod can be loaded into them machine, where after the process can be repeated.

(43) FIG. 13 schematically illustrates how the electric motor can be operated to first accelerate the first actuator part, during interval A, until it reaches a predetermined velocity. The electric motor is operated to maintain the first actuator part moving at said predetermined velocity during interval B, and to thereafter decelerate the movement during a further interval C. In a preferred embodiment of the invention, the first actuator part starts to displace the second actuator part after the predetermined velocity has been reached, and thereafter continues to move substantially at the predetermined velocity during interval D, during which expansion of the expanding element and cracking of the connecting rod takes place, with the two fractures. It has been found that carrying out the entire cracking in an interval in which the first and second actuator parts are moving at a substantially constant velocity helps make sure that subsequent crankshafts are cracked in a very similar manner, thereby ensuring repeatability of the process.

(44) FIG. 14 schematically illustrates the results of a test of a machine as described above, using a servomotor as the electric motor 400. A first graph 451 illustrates the theoretical velocity of the first actuator part (the left vertical axis indicates the speed of the motor, in rounds per minute; this velocity is proportional to the speed with which the first actuator part is displaced in the vertical direction); as shown by said graph, it was desired that the first actuator part should first accelerate until reaching a predetermined velocity (of about 600 mm/s, which in the embodiment of the invention that was tested corresponded to a motor speed of about 2700 rpm), at which it should be kept during the cracking process, and thereafter deceleration should take place. A second graph 452 illustrates the velocity of the motor as measured during the test, and a third graph 453 illustrates the motor current (the right-hand vertical axis indicates the effective motor current in A). In FIG. 14 it can be observed how no substantial breaking of the first actuator part took place during the cracking process, that is, the momentum of the first actuator part and the drive force of the motor were enough to perform cracking at a substantially constant speed. The current graph 453 shows high motor currents during acceleration (corresponding to interval A in FIG. 13) and deceleration (corresponding to interval C in FIG. 13), and in between there is a short current peak corresponding to the point of time when cracking takes place. It is clear from this graph that it is possible, by using an adequately programmed servomotor, to keep the speed of the actuator parts substantially constant during cracking, thereby achieving adequate process control and repeatability. In this test, the total amplitude of the displacement of the first actuator part in the vertical direction was about 70 mm, and the constant predetermined velocity of about 600 mm/s was substantially maintained during approximately 38 mm, including an interval before and after the cracking that took place at approximately 110 ms, where a current peak can be observed in FIG. 14.

LIST OF REFERENCE NUMBERS

(45) 1 first part of the machine

(46) 1A fixed part of the machine, which can be fixed in relation to said first part of the machine

(47) 2 second part of the machine

(48) 3 expandable element

(49) 4 electro press

(50) 11 first positioning elements

(51) 11A first positioning carriages, housing, for example, the actuators of the first positioning elements

(52) 11B first coupling means, for fixing the lateral position of the first position carriages; these first coupling means can be openings

(53) 11C second coupling means arranged to interact with the first coupling means to fix the position of the first position carriages; these second coupling means can comprise a blocking element to be inserted into one of the openings

(54) 11D joining structure

(55) 11E blocking means of the joining structure

(56) 11F horizontal guides

(57) 11G handwheel for displacing a blocking element 11C

(58) 11H vertical guide for the joining structure 11D

(59) 11I slots

(60) 11J openings in the vertical guide 11H

(61) 12 fluid outlets in the first positioning elements

(62) 13 fluid outlets

(63) 19 first sleeve portion

(64) 21 first carriage of the second part

(65) 22 second carriage of the second part

(66) 23 second positioning element

(67) 24 additional positioning elements

(68) 25 drive device/actuator

(69) 26 stops

(70) 29 second sleeve portion

(71) 31,32 expander mandrel halves

(72) 33 cleaving wedge

(73) 110 contact surface

(74) 111 spindle portion

(75) 190,290 screws

(76) 400 electric motor

(77) 401 spindle

(78) 402 output shaft of the electric motor

(79) 403 transmission means such as belt or chain

(80) 404 nut

(81) 410 first actuator part of the electro press

(82) 411 end portion of the first actuator part

(83) 412 carriage connected to the spindle

(84) 430 second actuator part of the electro press

(85) 431 retaining portion

(86) 431A vertical members

(87) 431B horizontal retaining members

(88) 432 end portion of the second actuator part

(89) 433 pressure sensor

(90) 451 desired velocity graph

(91) 452 measured velocity graph

(92) 453 motor current graph

(93) 1000 connecting rod

(94) 1001 rod

(95) 1002 cap

(96) 1003 small end

(97) 1004 stem

(98) 1005 small bore

(99) 1006 big bore

(100) 1007 screws

(101) 1008 joint between rod and cap

(102) A acceleration stage

(103) B stage with substantially constant, predetermined speed

(104) C deceleration/braking stage

(105) D expansion and cracking stage

(106) X distance between the first position and the intermediate position of the first actuator part

(107) In this text, the term “comprises” and its derivations (such as “comprising”, etc.) should not be understood in an excluding sense, that is, these terms should not be interpreted as excluding the possibility that what is described and defined may include further elements, steps, etc.

(108) On the other hand, the invention is obviously not limited to the specific embodiment(s) described herein, but also encompasses any variations that may be considered by any person skilled in the art (for example, as regards the choice of materials, dimensions, components, configuration, etc.), within the general scope of the invention as defined in the claims.