Source: http://www.google.com/patents/US6149292?ie=ISO-8859-1
Timestamp: 2014-12-20 20:26:04
Document Index: 340375791

Matched Legal Cases: ['art 3', 'art 5', 'art 5', 'art 3', 'art 3', 'art 5', 'art 3']

Patent US6149292 - Oscillating table, in particular for use in a continuous casting machine - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsThe oscillating table comprises a movable part on which a mould of a continuous casting machine is located. The movable part is coupled via eccentrics to a driving mechanism for introducing an upward and downward oscillation motion in order to prevent the cast steel from remaining stuck to the wall of...http://www.google.com/patents/US6149292?utm_source=gb-gplus-sharePatent US6149292 - Oscillating table, in particular for use in a continuous casting machineAdvanced Patent SearchPublication numberUS6149292 APublication typeGrantApplication numberUS 09/029,182PCT numberPCT/BE1996/000089Publication dateNov 21, 2000Filing dateAug 23, 1996Priority dateAug 25, 1995Fee statusLapsedAlso published asCA2228904A1, DE69616567D1, EP0846036A1, EP0846036B1, WO1997007910A1Publication number029182, 09029182, PCT/1996/89, PCT/BE/1996/000089, PCT/BE/1996/00089, PCT/BE/96/000089, PCT/BE/96/00089, PCT/BE1996/000089, PCT/BE1996/00089, PCT/BE1996000089, PCT/BE199600089, PCT/BE96/000089, PCT/BE96/00089, PCT/BE96000089, PCT/BE9600089, US 6149292 A, US 6149292A, US-A-6149292, US6149292 A, US6149292AInventorsHubert DegrandeOriginal AssigneeSidmar N.V.Export CitationBiBTeX, EndNote, RefManPatent Citations (12), Non-Patent Citations (2), Referenced by (3), Classifications (7), Legal Events (4) External Links: USPTO, USPTO Assignment, EspacenetOscillating table, in particular for use in a continuous casting machineUS 6149292 AAbstract The oscillating table comprises a movable part on which a mould of a continuous casting machine is located. The movable part is coupled via eccentrics to a driving mechanism for introducing an upward and downward oscillation motion in order to prevent the cast steel from remaining stuck to the wall of the mould. In contradistinction to the known oscillating tables according to the invention the eccentrics are not uniformly driven. To this end the driving mechanism comprises driving means for driving the eccentrics with a non-uniform angular speed. In a preferred embodiment the driving means comprise hydraulic motors provided with a control system. The hydraulic motors are electronically synchronised and as a safeguard being coupled to each other by a synchronisation shaft. In this way the facility is obtained to operate any lifting and descending motion of the casting mould.
What is claimed is: 1. Oscillating table, in particular for use in a continuous casting machine, comprising a movable part, coupled via two eccentrics to a driving mechanism for introducing an upward and downward oscillation motion, wherein the driving mechanism comprises driving means for driving the eccentrics with a non-uniform angular speed; and wherein the driving means comprises one hydraulic motor for each eccentric, said hydraulic motors being provided with a control system; and wherein the control system comprises for each hydraulic motor a control element chosen from the group consisting of hydraulic servo and proportional valve and an electronic controller for controlling the control elements; and wherein the driving mechanism comprises means for synchronising the two hydraulic motors.
2. Oscillating table according to claim 1, wherein the synchronising means comprises measurement means for indicating the exact position of the motors, which measurement means are coupled to the control system.
3. Oscillating table according to claim 2, wherein the synchronising means comprises a mechanical synchronisation means coupled to both hydraulic motors.
4. Oscillating table according to claim 3, wherein the mechanical synchronisation means comprises a synchronisation shaft.
5. Oscillating table according to claim 1, wherein the synchronising means comprises a mechanical synchronisation means coupled to both hydraulic motors.
6. Oscillating table according to claim 5, wherein the mechanical synchronisation means comprises a synchronisation shaft.
This application claims priority and benefit of U.S. Provisional Application Ser. No. 60/002,818 filed on Aug. 25, 1995 (See: 60 Fed. Reg. 79, at 20212, Apr. 25, 1995).
BACKGROUND OF THE INVENTION The present invention pertains to an oscillating table, in particular for use in a continuous casting machine, comprising a movable part, coupled via an eccentric to a driving mechanism for introducing an upward and downward oscillation motion.
In a continuous casting machine, used i.a. in steel production, the oscillation table is used to impart to the casting mould an upward and downward oscillation motion, either according to a defined radius or, less frequently, along a vertical direction in order to prevent the cast steel from remaining stuck to the water-cooled copper wall of the mould.
In the presently in use oscillating tables, the applied oscillation frequency is dependent upon the casting speed. The amplitude is fixed but is generally adaptable by exchanging eccentrics.
In the upward motion of the casting mould, there is always a relative speed difference between slab, billet or bloom being formed and the casting mould.
In the downward motion of the casting mould, the speed of the casting mould is initially less than, subsequently equal and thereafter greater than, the speed of the slab, billet or bloom. Upon the end of the descending motion, the speed of the casting mould is again equal to and thereafter less than the speed of the slab.
The period during which the speed of the casting mould in the downward motion is greater than the speed of the billet is referred to as the "negative strip".
The usual driving mechanisms for oscillating tables use linear electric motors driving eccentric shafts via reduction gearboxes and driving shafts. This results in a sinusoidal movement which is not satisfactory because the time during which the speed of the slab is nearly equal to the speed of the mould during the downward movement of the mould and causes the cast steel to stuck to the wall of the mould is too long.
SUMMARY OF THE INVENTION It is a goal of the invention to provide an oscillating table of the type mentioned hereabove, whereby the drawbacks of existing oscillating tables are avoided. To this end, the oscillating table according to the invention is characterised in that, the driving mechanism comprises driving means for driving the eccentric with a non-uniform angular speed. In this way the facility is obtained to operate any lifting and descending motion of the casting mould. By maximizing the negative strip, i.e. by raising the downward speed of the casting mould to a considerably higher value than that of the upward speed, the period during which the cast steel strikes onto the wall of the mould because of the too small difference in speed is not long enough for the cast steel to stuck to the wall of the mould.
An embodiment of the oscillating table according to the invention is characterised in that the driving means comprises a hydraulic motor provided with a control system. By way of a hydraulic motor a non-uniform angular speed of the outgoing driving shaft can be easily obtained by controlling the pressure of the supplied hydraulic oil.
An advantageous embodiment is characterised in that the control system comprises a hydraulic servo or proportional valve and an electronic controller for controlling the servo or valve.
In practice the oscillating table is nearly always driven via more than one eccentric. A further embodiment of the oscillating table according to the invention is characterised in that the driving mechanism comprises a further eccentric driven by a further hydraulic motor and means for synchronising the two hydraulic motors.
The motors need to have perfect synchronization. To this end still a further embodiment is characterised in that the synchronising means comprises measurement means for indicating the exact position of the motors, which measurement means are coupled to the control system. By interaction between the electronic controller for controlling the hydraulic servo or proportional valves and the position measurements of the motors, perfect synchronization is obtained.
A preferred embodiment is characterised in that, the synchronising means comprises a mechanical synchronisation means coupled to both hydraulic motors. This mechanical synchronisation means can be applied instead of the mentioned electronic synchronization or as a safeguard besides the electronic synchronization.
In a practical embodiment, the mechanical synchronisation means comprises a synchronisation shaft.
The invention will now be further elucidated on the basis of an example embodiment of the oscillating table according to the invention, as depicted in the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a plan view of a oscillation table according to the invention;
FIG. 2 shows a side view of the oscillating table; and
FIG. 3 shows a chart depicting a non-uniform motion of the oscillating table.
DETAILED DESCRIPTION FIGS. 1 and 2 show an oscillating table 1 according to the invention at different views. The oscillation table 1 which supports a casting mould (not shown) comprises a fixed part 3 and a moving part 5. The casting mould is tightened by four bolts on the top side of the movable part 5 (=oscillating portion). The fixed part 3 rests on the outer edges on fixed racks 7 (anchored in the concrete structure).
At each corner of the fixed part 3 there is a combined mounting with eccentric. The eccentric shaft 9 is beared in two fixed bearings 11 at each side of the eccentric 13. Attached to the eccentrics 13 are connecting rods 15, by which the moving part 5 is suspended. The eccentrics 13 are coupled to the connecting rods by moving eccentric bearings. These eccentrics 13 are connected two by two by a connecting shaft 17.
On the outer side of the fixed part 3 there are placed on the eccentric shafts 9 hydraulic motors 19, which drive the two eccentrics 13 and thus generate an upward and downward motion of the casting mould. These hydraulic motors 19 replace the usual linear electric motor which drives the eccentric shafts via reduction gearboxes and driving shafts.
Each motor 19 has a connection to a bevel gearbox 21 by teethcoupling 23. The connection between the gearbox 21 and the eccentric shaft 9 is provided with a free play elastic coupling 25.
The motors 19 are controlled by a control system. The control system comprises hydraulic servos or proportional valves 27 and an electronic controller 29 for controlling the servos or valves. The hydraulic motors 19 and the control system are part of driving means for driving the eccentrics 13 with a non-uniform angular speed.
The drive is effected with the servos or valves 27 installed as close as possible to the motors 19, possibly provided with the necessary accumulators for each motor control system.
The driving means on their turn are parts of an overall driving mechanism of the oscillating table.
The hydraulic oil is supplied under pressure. The hydraulic pressure is determined by the mass to be accelerated and the actual acceleration required.
In contradistinction to the solution of the state of the art, according to the invention the motors are not uniformly driven. During the downward motion of the casting mould, a much greater speed is indeed sought than during the upward motion. In order to make the negative strip as large as possible, the transition from high (descend) to low speed (ascend) can take place, for example, in the ascendant motion.
The braking, the transition to a uniform or non-uniform slow lifting speed and the acceleration to high descending speed takes place during the upwards motion of the slab.
In order to realise this kind of oscillation control, the angular speed of the hydraulic motors has to be continuously adjustable. With this continuous adjustment, an optional sinusoidal or other form can be set.
In the chart, shown in FIG. 3, an example of a non-uniform motion with fast descending and slow ascending speeds is depicted.
The hydraulic motors 19 are not uniformly driven. At each moment the speed on both motors must be equal. The speed on both motors 19 is realised by interaction of the electronic controller 29.
The position of the motor 19 is monitored by an absolute-value transmitter or pulse generator 31 for each motor or any other system which indicates the exact position of the motors.
The motors need to have perfect synchronization, which is realized by interaction between the electronic controller 29 for controlling the hydraulic servo or proportional valves 27 and the position measurements of the motors. As a safeguard, an additional mechanical synchronization i.a. a mechanical synchronization shaft 33 is provided between both gearboxes 21. If there is a failure on the electronic controller 29 for example, at this moment the mechanical synchronization guarantees that both motors 19 are in phase. Even when one of the motors 19 is out of service, both eccentric shafts 9 are still driven (one eccentric shaft is driven with the synchronization shaft at this moment).
The hydraulic motors 19 in question can be of the axial or radial type: hydraulic gear wheel or baffle motors also being possible.
By equipping an oscillation table with hydraulic motors provided with a control system which allows a variable angular speed for each revolution, the facility is obtained to operate any lifting and descending motion of the casting mould. The higher the acceleration (dependent upon the controller and the mass to be accelerated), the greater is the approximation to a sawtooth shape.
Although the invention has been elucidated on the basis of the accompanying drawings in the discussion to this point, it should be noted that the invention is in no way restricted to just this embodiment depicted in the drawings. The invention also encompasses all the derivative embodiments which differ from the depicted embodiment within the scope defined in the claims. As an example, it is also possible to omit the mechanical synchronisation shaft or to drive all eccentrics by one hydraulic motor. Further, instead of hydraulic motors, other motors can also be used which are able to excite a non-uniform motion. It is also to be noted that the oscillating table is not restricted for use in continuous casting machines but that the oscillating table in accordance with the present invention can be used anywhere where oscillating tables are applied.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS3407670 *Mar 21, 1966Oct 29, 1968Michele VenanzettiVibrating eccentric mass device comprising one or more pairs of vibrators independently rotating in opposite direction to one anotherUS3724819 *Nov 24, 1971Apr 3, 1973Garver FApparatus and method for the vibratory feeding of pulverulent and granular materialsUS3866480 *Jun 2, 1972Feb 18, 1975Martin Concrete Eng CoOrbital vibratorUS4151982 *Jun 20, 1977May 1, 1979L. B. Foster CompanyApparatus for cleaning metallurgical vessels such as slag pots and ladlesUS4202634 *Sep 22, 1978May 13, 1980Kraft Harold DRack for vessels and means for agitating the vessels in the rackUS4262549 *May 10, 1978Apr 21, 1981Schwellenbach Donald DVariable mechanical vibratorUS4766771 *Mar 12, 1986Aug 30, 1988Outboard Marine CorporationVariable unbalanced rotating mechanismUS4860816 *Sep 15, 1988Aug 29, 1989General Kinematics CorporationControl system for vibratory apparatusDE2232718A1 *Jul 4, 1972Jan 24, 1974Vaw Ver Aluminium Werke AgVorrichtung zur herstellung von formkoerpern durch verdichtungFR1235705A * Title not availableFR1266961A * Title not availableFR1275262A * Title not available* Cited by examinerNon-Patent CitationsReference1 *Abstract of Japanese Patent Publication 57 12549.2Abstract of Japanese Patent Publication 57-12549.* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS6575614 *May 8, 2001Jun 10, 2003Fata Aluminium Division Of Fata Group S.P.A.Bearing system for a sand container to be vibrated in a lost foam casting apparatusUS6808304 *Aug 27, 2002Oct 26, 2004Dade Behring Inc.Method for mixing liquid samples using a linear oscillation strokeCN101648259BAug 26, 2009Jun 29, 2011中冶连铸技术工程股份有限公司Vibrating device for continuous caster crystallizer* Cited by examinerClassifications U.S. Classification366/111, 164/261, 366/128International ClassificationB22D11/04, B22D11/053Cooperative ClassificationB22D11/053European ClassificationB22D11/053Legal EventsDateCodeEventDescriptionJan 18, 2005FPExpired due to failure to pay maintenance feeEffective date: 20041121Nov 22, 2004LAPSLapse for failure to pay maintenance feesJun 9, 2004REMIMaintenance fee reminder mailedJul 24, 1998ASAssignmentOwner name: SIDMAR N.V., BELGIUMFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:DEGRANDE, HUBERT;REEL/FRAME:009346/0154Effective date: 19980306RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google