WO2002047852A1

WO2002047852A1 - Stopper rod actuator

Info

Publication number: WO2002047852A1
Application number: PCT/SE2001/002736
Authority: WO
Inventors: Sune Johansson; Sören LÖF
Original assignee: Sune Johansson; Loef Soeren
Priority date: 2000-12-11
Filing date: 2001-12-11
Publication date: 2002-06-20
Also published as: AU2002222856A1; SE0004551L; SE0004551D0; SE520595C2

Abstract

The invention relates to a stopper rod actuator for displacement and positioning of the rod in desired positions. The actuator comprises a carrier (7), which is mountable on a stand (5) and which, when it is mounted on the stand, exends from the stand, which carrier in one end thereof carries a fixed hauling path unit (45), a holder (16) including members (31-33) provided to keep the stopper rod by a firm grip, which holder is moveable along and relative to the hauling path unit, and motion devices (14, 55, 58, 60) for the displacement of the holder and thence of the stopper rod relative to the hauling path unit in the direction of the holder for said displacement and positioning of the rod in desired positions.

Description

STOPPER ROD ACTUATOR

The invention generally speaking relates to the metallurgy technical field, e.g. foundries, melting shops and steel mills, and more specifically to an actuator for a stopper rod intended to be able to be manipulated relative to a casting hole or pouring hole in a launder, pour cup or other metallurgical vessel.

BACKGROUND OF THE INNEMTION

Advanced equipment are available for the control of the flow of molten metal in connection with automized metal casting, see e.g. internet cite www.lmint.com/Lase ourCgflron Automatic Pouring Systems. In these and other well known casting equipments there are included a stopper rod, which shall be able to be manipulated in the vertical direction relative to a pouring or casting hole by means of a stopper rod actuator, e.g. for controlling the level of molten metal in a launder or a pour cup.

The two most common stopper rod actuators which are employed in foundries are lever- controlled and linear stopper rod actuators having a fixedly mounted arm. The first type, the lever-controlled actuator, gives very low friction losses. It is a drawback that the stopper rod in these machines describes a radius during its movement, which has the effect that the stream of molten metal leaving the launder, tundish or ladle or corresponding often will be inclined, because the stopper rod may have a tendency to be eccentric relative to the pouring or casting hole. The latter type, stopper rod actuators having a fixedly mounted arm, perform a linear movement, which makes it possible to obtain a fine and concentric stream of molten metal. The principle drawback is the comparatively long arm, which leads to a bending movement on those bearings which shall absorb the movement forces. This in turn causes an increased friction and a larger inertia factor. These conditions affect the operation of the actuator negatively, which makes it difficult to achieve a perfect control of the stopper rod and therefore a risk of inferior casting results.

It is also a typical feature of existing actuators that the driving unit is located adjacent to a metallurgical vessel, such that it will be subject to a high temperature, which causes an increased wear. Therefore, there is a demand of improvements within this technical field. DISCLOSURE OF THE INNENTION

It is the purpose of the invention to address the above mentioned problems. It is a particularly a purpose to provide a stopper rod actuator designed such that the power transmission of the actuator is not subjected to any essential bending movement. It is also a purpose to make it possible to provide a power force, i.e. any kind of motor in the most general sense of this word, for said motion device at a substantial distance from the stopper rod and in other respects to design the actuator in such a way that sensitive parts are protected from the contamination which normally occurs in the environment in which the actuator is intended to be used.

These and other objectives can be achieved therein that the actuator is characterised by what is stated in the appending patent claims.

Further characteristic features and aspects of the invention will be apparent from the following, detailed description of a preferred embodiment of the invention.

BREIF DESCRIPTION OF DRAWINGS

In the following detailed description reference will be made to the accompanying drawings, in which

Fig. 1 is a perspective view of the actuator according to the preferred embodiment of the invention; Fig. 2 shows a front view of the actuator, i.e. from the right in Fig. 1; Fig. 3 is a top view of the actuator;

Fig. 4 is a side view of the actuator, mounted on a stand and carrying a stopper rod; Fig. 5 is a perspective view showing a unit included in the actuator at a larger scale, said unit including a holder for the stopper rod; Fig. 6 shows the unit according to Fig. 5, and the parts included in and connected to said unit, from below;

Fig. 7 is a view along the line NII-Nπ in Fig. 6, in which the inner parts of the unit according to Fig. 5 are illustrated by an "x-ray picture"; Fig. 8 shows a perspective view of one of four roller chain sections which are included in the actuator and which are shown in Fig. 6 and Fig. 7; and Fig. 9 shows an end view of said roller chain sections. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT An actuator is generally designated 1 in Fig. 1-4. It is mounted on a stand 5 via a mounting plate 3, which is secured to a vertical post 2 by means of strappings 4. The post 2 consists of a cylindrical pipe. A horizontal carrier 7 is fastened to the post 2 via an arm 8, which in turn is fastened to the post 2 via a clamping sleeve 9 and screw couplings 10. In the same manner the carrier 7 is fastened to the arm by means of a clamping sleeve 11 embracing the carrier, and screw couplings 12. Also the carrier 7 consists of a cylindrical pipe. This has a considerably large diameter, which provides a large bending resistance to the carrier 7. By loosening the screw couplings 10 the arm 8 and the carrier 7 can be displaced along the post 2 in order to adjust the vertical position of the carrier 7 and also be turned about the post. In a corresponding manner, the carrier 7 can be displaced in the horizontal direction, after the screw couplings 12 have been loosened. At the rear end of the carrier 7 there is a driving unit, here denominated motor 14, which according to the embodiment consists of a pneumatic turning cylinder. Also other driving units/motors, however, can be conceived. In the opposite, front end of the carrier 7 there is a guide unit, generally designated 15, which among other things includes an in the vertical direction moveable holder 16 for a stopper rod 17.

The holder 16, Fig. 5, includes a casing 20, which consists of a bent plate having a flat, broad front portion 21. Along each longitudinal side there are a pair of first side portions 22 and 23, respectively, which are angled rear wise and form an angle of 135° to the front portion 21. Further there are a pair of second side portions 24 and 25, respectively, which are angled inwards and form an angle of 90° to the first side portions 22 and 23, respectively. The casing 20 is open in the rear vice direction. The opening is designated 26. At the ends of casing 20 there are a pair of brackets 27, 28 mounted on the outer sides of the second side portions 24, 25. A pair of rigging screws 29 extend between the brackets 27 and 28. Further, a pair of brackets 30 are welded to the vertical front side 21 of the vertical casing 20 and extend horizontally forwards from said front side. Between the brackets 30 there is fastened by welding a first fastening member for the stopper rod 17 in the form of a secured cramp half 31. A correspondingly designed cramp cover 32 is fastened by screwing to the cramp half 31 by means of screws 33 for clamping the stopper rod 17 in the cramping device consisting of the cramp half 31, the cramp cover 32 and said screws.

The insides of the side portions 22-25 are flat and vertical and define roller-ways 22a, 23a, 24a and 25a for a vertical guide 45 inside the casing 20 of the holder 16. The guide has the shape of a comparatively flat, symmetrical prism having a first broad side 46 facing the open rear side of the casing 20, a second broad side 47 facing the front portion 21 of the casing, and two narrower short sides 48-51 on each side of the two broad sides. The first side 46 is parallel with the second side 47 and with the front portion 21 of the casing and in a corresponding way the short sides 48-51 are parallel with the roller-ways 22a-25a. The prism-shaped guide 45 thus has a shape in cross section which is uniform to the contour of the casing 20.

A roller chain section 36, Fig. 8 and Fig. 9, is fastened by welding to each of the short sides 48-51 of the guide 45. The roller chain elements 36 extend in the vertical direction and are centred along about % of the full length of the short sides 48-51 and consist of six rolls 37, which are journalled on roller shafts 38, which extend between chain links 39, 40. The roller shafts 38 are displaced in the lateral direction relative to the longitudinal centre line of the links 39, 40 and have such a width relative to the rolls 37 that they project beyond the periphery of the rolls 37 on one side 41 and so that the rolls 37 project beyond the opposite side 42 of the links 39, 40. The first mentioned, projecting sides 41 abut and are fastened by welding to the short sides 48-51 of the guide 45. The rollers 37 of the roller chain sections contact the roller-ways 22a-25a and are pressed by some power against said roller-ways by means of the rigging screws 29, such that they, freedom from play, can roll against the roller-ways 22a-25a on the inside of the casing 20.

The tubular carrier 7 is terminated at its rear end by a short, tubular portion 54, which is fixedly connected, e.g. by welding, to the first side 46 of the guide 45. Through the tubular carrier 7 there extends a rotatable shaft 55 from the motor 14, which is provided to rotate the shaft 55. The rotational shaft 55, which does not contact the carrier 7, also extends through a through hole in the guide 45 and is journalled in a bearing 56, which is pressed into the guide 45 adjacent to the second side 47 of the guide. In its front end, the rotation shaft 55 is engaged with a gear 58, which is provided in a gap 59 between the second side 47 of the guide and the front portion 21 of the casing. In the gap 59 there is also a vertical rack 60 which is connected to the holder 16 on the inner side of the front portion 21 of the casing 20 by means of screws. The gear 58 is in engagement with the rack 60, which extends along about a third of the length of the casing 20. This also can be expressed such that the rack 60 is about half as long as the roller chain sections 36.

The thus described actuator functions in the following way. The actuator is intended to be used in foundries for multiple production of castings. The lateral positioning of the stopper rod 17 relative to the stand 5 and also the approximate vertical position therefore is fixed during at least longer series of production. The starting position for the functioning of the actuator therefore can be regarded as fixed, once the carrier 7 has been positioned in its longitudinal and vertical direction as well as of its angular position relative to the post 2 which is mounted on the stand. The stopper rod 17 now, by means of the actuator 1, shall be possible to be adjusted with great accuracy by linear movements in the vertical direction for controlling the flow of molten metal through a casting hole and also be able completely to stop the flow in the bottom position of the stopper rod. In a conceived application, the casting hole is provided in the bottom of a not shown casting ladle, which during the performance of the casting operation is placed at the side of the stand 5. The stand 5 is stationary and is not connected to the casting ladle.

The shaft 55 is rotated by means of the motor, i.e. the pneumatic turning cylinder 14. The rotational movement of the shaft 55 is transferred to a vertical, linear movement of the rack 60 via the gear 58, The rack 60, which is secured to the holder 16 lowers or raises therefore the holder 16 and thence also the stopper rod 17. The rolls 37 of the roller chain units 36, which are connected to the pairwise angled short sides 48-51 of the stationary guide, roll against the roller ways 22a-25a on the inside of the casing 20 which are parallel with said short sides, wherethrough the guide 45 guides the holder 16 during its movement. The bending moment which the stopper rod 17 develops upon the actuator 1 is essentially absorbed by the sturdily designed, tubular carrier 7, which has a great bending resistance, which implies that the motion devices, in the first place the rotational shaft 55, are not subjected to any essential bending moment, since the bearing 56, which is a radial bearing of the shaft, is mounted in the guide 45, which in turn is fixedly connected to the carrier 7.

It should be realised that various modifications of the invention are conceivable. Also the mode of operation can be varied, including the mode of operation of the described actuator. E.g., the carrier 7 and the hauling path unit 45 also can be oriented in other directions than the horizontal and the vertical direction, respectively, i.e. in the vertical and the horizontal direction, respectively, and the holder 16 can be caused to perform movements in other directions than the vertical direction, i.e. in the horizontal direction.

Claims

PATENT CLAIMS

1. Stopper rod actuator for displacement and positioning of the rod in desired positions, characterized in that it comprises a carrier (7), which is mountable on a stand (5) and which, when it is mounted on the stand, extends from the stand, which carrier in one end thereof carries a fixed hauling path unit (45), a holder (16) including members (31-33) provided to keep the stopper rod by a firm grip, which holder is moveable along and relative to the hauling path unit, and motion devices (14, 55, 58, 60) for the displacement of the holder and thence of the stopper rod relative to the hauling path unit in the direction of the holder for said displacement and positioning of the rod in desired positions.

2. Actuator according to claim 1, characterized in that said motion devices comprise a motor (14) at a distance from said holder and a power transmission (55, 58, 60) between the motor and the holder.

3. Actuator according to claim 2, characterized in that the power transmission comprises a rotational shaft (55) provided to be rotated by the motor (14), which is provided to perform a turning moment on said shaft, and a transmission unit (58, 60) in connection to the holder, said transmission unit transforming the rotational movement of the shaft into a linear, vertical movement of the holder.

4. Actuator according to claim 3, characterized in that the rotational shaft extends essentially the whole way from the motor to the holder.

5. Actuator according to claim 4, characterized in that the shaft extends through the carrier.

6. Actuator according to claim 5, characterized in that the shaft and the carrier are horizontal.

7. Actuator according to claim 6, characterized in that the carrier which is mounted on the stand extends beyond said stand, that the hauling path unit and the holder are provided in one end of the carrier on one side of a vertical plane through the stand, and that the motor is provided in the other end of the carrier on the opposite side of said vertical plane.

8. Actuator according to claim 7, characterized in that the carrier is adjustable in different positions relative to the stand.

9. Actuator according to any of claims 1-8, characterized in that the carrier is mountable on a vertical post (2) which in turn is mountable on the stand.

10. Actuator according to any of claims 1-9, characterized in that the carrier consists of a tube, and that the shaft does not touch the tube along essentially the whole length of the tube.

11. Actuator according to claim .1, characterized in that the holder has the shape of a casing (20) which partly surrounds the hauling path unit (45), that the casing has an opening (26) on the side facing the carrier, that the carrier extends through said opening all the way to the hauling path unit with which it is fixedly connected, and that said members (31-33) for firm holding the stopper rod is provided on a portion (21) of the holder which is turned from said opening.

12. Actuator according to claim 11, characterized in that the guide (45) is provided with a plurality of rollers (37) having horizontal shafts (38), which rolls are carried by bearing members (39, 40) which are united with the guide, and that the rollers contact a plurality of vertical roller-ways (22a-25a) on the inside of the casing (20).

13. Actuator according to claim 12, characterized in that the holder is carried by the guide (45) which is connected to the carrier, via a vertical rack (60) which is fixedly connected to the holder on the inside of the holder, said rack together with a gear (58) provided at the front end of the shaft forming said transmission unit for transforming the rotational movement of the shaft into a vertical, linear movement of the holder.

14. Actuator according to any of claims 12-13, characterized in that the inside of the casing (20) has at least three vertical roller- ays forming an angle to one another.

15. Actuator according to claim 14, characterized in that the guide has the substantial shape of a prism, and that the rollers, by their bearing members, are provided on a corresponding number of sides (48-51) of the prism, said sides being parallel with the roller-ways on the inside of the casing.

16. Actuator according to claim 15, characterized in that the guide has the shape of a comparatively flat, symmetric prism having a first broad side (46), which is united with the carrier, a second broad side (47) on the opposite side of the guide, and a pair of narrower short sides (48-51) on each sides of the two broad sides, on which short sides said rollers are mounted via their bearing members.

17. Actuator according to any of claims 15 and 16, characterized in that the shaft extends rotatably through the guide, and that the gear and the rack are provided in a gap (59) between said second broad side of the guide and said casing (20),

18. Actuator according to claim 17, characterized in that the shaft is journalled in the guide.

19. Actuator according to any of claims 1-17, characterized in that the hauling path unit is vertically oriented and that the holder, and hence the stopper rod, are provided to be displaced in the vertical direction.

20. Actuator according to any of claims 1-17, characterized in that the hauling path unit is horizontally oriented and that the holder and hence the stopper rod are provided to be displaced in the horizontal direction.