US3461950A

US3461950A - Apparatus for producing adjustable reciprocation of a continuous casting mold

Info

Publication number: US3461950A
Application number: US590291A
Authority: US
Inventors: Anatol Michelson
Original assignee: EW Bliss Co Inc
Current assignee: EW Bliss Co Inc
Priority date: 1966-10-28
Filing date: 1966-10-28
Publication date: 1969-08-19
Anticipated expiration: 1986-08-19
Also published as: CH456860A; BE705744A

Description

Aug. 19. 1969 I A. WELSQN 3.461,950

PROCATIQN APPARATUS FOR PRODUCING ADJUSTABLE RBCI OF A cou'rmuous CASTING MOLD 2 Sheets-Sheet 1 Filed Oct. 28. 1966 INVENTOR. ANATOL M/cHELso/v BY v WW flA/W ATTORNEYS;

A MICHEL-SON 7 ,FOR PRODUCING ADJUSTABLE RECIPROCATION 0F A1 CONTINUOUS CASTING MOLD Aug. 19',

APPARATUS aud o. 28, 1966 2 Sheets-Sheet 2 v v 4 lg.

INVENTOR. ANA-rot. M/CHELSON ATTORNEYS.

United States Patent 3,461,950 APPARATUS FOR PRODUCING ADJUSTABLE RE- 1(@{IglfigCATION OF A CONTINUOUS CASTING Anatol Michelson, Glenolden, Pa., assignor to E. W. Bliss Company, Canton, Ohio, a corporation of Delaware Filed Oct. 28, 1966, Ser. No. 590,291 Int. Cl. B22d 11/00, 27/08; F01] 31/00 US. Cl. 164260 3 Claims ABSTRACT OF THE DISCLOSURE Apparatus for producing adjustable reciprocation of a continuous casting mold. The disclosed apparatus includes a frame for supporting a continuous casting mold and an hydraulic cylinder for reciprocating the mold. Supply of hydraulic fluid to the cylinder is controlled by a fourway control valve actuated by movement of the frame transmitted to the valve operator through an adjustable lost motion connection.

is withdrawn continuously from the bottom. In steel casting, the ingot is only partially solidified upon leaving the mold having a deep liquid center with a solid but fragile skin. The skin is subject to being torn due to friction against the sides of the mold. In the event of a tear, molten metal from the interior of the ingot will run against the mold and solidify, requiring an interruption of the casting process.

To solve this problem, a lubricant may be introduced between the ingot and the mold in order to reduce the friction. Also, the mold may be reciprocated parallel to the mold axis so that the ingot travels with the mold on the downstroke eliminating relative movement between the mold and ingot except on the upstroke. The risk of tearing is not as great owing to the better skin formed on the downstroke and the rate of reciprocation employed on the upstroke.

Heretofore, various reciprocating devices have been tried involving springs, cams and cam followers arranged to import a prescribed, periodic, time-displacement oscillation to the mold. However, the same mold movements are not always suited to the solidfication characteristics of all types of steels. Thus, largely by trial and error during the casting of the first heat of a new steel, the mold reciprocation is matched to the casting properties of the metal. The critical period is at the start of casting the new steel when it is necessary to coordinate the frequency and amplitude of the mold reciprocations with the particular solidification rate of the metal. Known prior art mold reciprocators are deficient in means to adjust the mold stroke or frequency while casting is in progress.

Another problem with prior art mold reciprocators is that their cam and spring mechanisms become worn in time causing deviations in the mold time-displacement relationship. Also, where two actuators are employed on 3,461,950 Patented Aug. 19, 1969 ice opposite sides of the mold, the reciprocator guides are subject to misalignment causing the mold to seize on the guides.

Moreover, the prior art mold reciprocators are so arranged with respect to the mold that when it is desired to exchange molds between heats, much time and labor is required since this can only be done from above the mold.

Also, no practical mold reciprocator is known which can operate with curved as well as straight molds.

These and other difficulties are overcome with the present invention by providing a mold reciprocator which is adjustable during casting, may be used with straight or curved molds, allows mold exchange from the side and is designed to operate without the use of cams or mold oscillation springs.

In accordance with the invention, a mold reciprocator comprises a pair of mold guides, one on each side of the mold, reciprocal parallel to the mold axis. An actuator is connected to the mold guides for imparting reciprocal movement thereto. A pair of control elements, one being capable of bidirectional adjustment relative to the other so as to vary the space therebetween, is positioned adjacent the actuator. And an operator, responsive to the movements of the actuator, is arranged to control the mold reciprocations in accordance with a periodic timedisplacement function as determined by the set spacing of the control elements.

In accordance with a further aspect of the invention, and particularly to permit mold exchange from the side, a U-shaped frame surrounds the mold on three sides housing the mold reciprocator mechanism.

Also, to reciprocate curved or straight molds, the mold guides may be curved or straight depending upon the mold. And the mold reciprocator mechanism includes a U-shaped lever pivoted on opposite sides of the mold and is operated by a single hydraulic cylinder connected at one ,end thereof to prevent misalignment of the mold on the guides.

It is the main object of the invention to provide a mold reciprocator which can be adjusted during the casting process so that the frequency and amplitude of reciprocation imparted to the mold can be suited to the type of metal being cast.

Another object is to provide a mold reciprocator operated by means of a single hydraulic cylinder in conjunction with a linkage mechanism which will not be subject to distortion causing the mold to seize on its guides.

Still another object is to provide a practical and workable mold reciprocator capable of straight or curved movements which can be used therefore with either straight or curved molds.

A further object is to provide a mold reciprocator, the arrangement of which with respect to the mold permits mold exchange from the side thereby saving much time and labor.

These and other objects and advantages will be more apparent by referring to the following description and drawings wherein:

FIGURE 1 is a partial side view showing the invention used in conjunction with a curved continuous casting machine;

FIGURE 2 is a side view of the mold reciprocator constructed in accordance with a preferred embodiment of the invention;

FIGURE 3 is a horizontal sectional view taken along line 33 of FIGURE 2;

FIGURE 4 is a fragmentary vertical sectional view taken along line 44 of FIGURE 2; and

FIGURE 5 is a sectional view of a control assembly for the mold reciprocator taken along line 55 of FIGURE 3.

Referring now to the drawings where the showings are for the purpose of illustrating a preferred embodiment of the invention only and not for the purpose of limiting same, FIGURE 1 depicts a water cooled, flow-through mold M which receives molten metal from a ladle L positioned above the pouring floor F. The mold M is curved so that a curved ingot I will be withdrawn therefrom. However, the mold might just as well be straight, in which case the ingot is either bent through a 90 arc after leaving the mold or remains straight depending on the type of casting plant. The ingot will have a fragile, but solid outer skin S upon leaving the mold and a deep liquid center H. Solidification is completed at some distance below the mold M depending on the cooling provided primarily by water cooling jets I. Support rolls R guide the ingot during the solidification processv Terminal equipment such as Withdrawl and straightening rolls and a cutting mechanism (not shown) would be provided in the normal casting plant.

Primarily to prevent tearing of the skin S and to increase the casting rate, the mold M is reciprocated by a mold reciprocator indicated generally at 10. In accordance with the preferred embodiment of the invention, the mold reciprocator 10, as shown in FIGURES 2-5, includes a U-shaped frame 12 surrounding three sides of the mold M. A double acting hydraulic cylinder 14 positioned centrally within the frame has its piston rod 15 connected to a U-shaped lever 17 which fits within the frame 10. The lever 17 is pivoted at 18 within the leg portions 19 which extend on opposite sides of the mold. Pairs of bushings 20 in each leg portion 19 each receive a mold guide 22 located on opposite sides of the mold which has a curvature coinciding with that of the mold. Mold holders 25 on each mold guide have hinge clamps 26 which are releasably engageable with a mold flange 27. A pair of bifurcated ends 30 on the lever 17 link with a collar 32 secured around each mold guide 22. A pair of links 34 connect the lever 17 and mold guides 22. As the hydraulic piston 15 is extended and returned, the lever 17 oscillates about pivots 18 causing the mold guides 22 to reciprocate the mold in a prescribed manner. As aforementioned, it is essential that the mold stroke be a periodic movement which is consistent with the casting properties of the metal. Experience has shown that it is practically impossible to predict beforehand the proper stroke and that only after casting has begun can meaningful adjustments be made.

In accordance with the invention, the mold stroke is adjusted during operation from a remote location by means of crank 39 which operates a hydraulic control 40 inside the frame 12. The control 40 as best shown in FIGURES 3 and 5 and generally includes a four-way control valve 42 of standard design, a valve operator 44, a reciprocal and rotatable operating rod 45 and a pair of discs 46, 47 having contact surfaces. Disc 46 is on a threaded portion 48 of the operating rod 45 and is held against rotation by means of a slot 50 which engages a lug 51 on a support bracket 52. Disc 47 is fixed on the operating rod 45. On the U-shaped lever 17 are two bosses 53 each having a known diameter D. Each boss 53 is located in the space between the discs 46, 47 which are set at a known spacing L. A reduced diameter portion 54 of the valve operator 44 is received in a hollow end of the operating rod 45. A coil spring 55 surrounds the reduced diameter portion 54 and bears against a washer 56 on the end of valve operator 44 and a shoulder 57 on the end of rod 45. The shoulder 57 also engages the valve operator 44 at 58. The valve 42 has a fitting 60 connected to a source of hydraulic pressure and alternate delivery and return fluid lines 61, 62 in fluid communication with the opposite ends of the hydraulic cylinder 14. Rotation of the operating rod 45 for adjusting the distance L between the discs 46, 47 is provided for by means of bevel gear 66 which is mounted on bushing 67 keyed to the end of the operating rod 45. The crank 39 carries on its end a bevel gear 68 engageable with the 4 bevel gear 66. As can be clearly seen in FIGURE 5, this arrangement permits the operating rod 45 to reciprocate within bushing 67 while allowing rotary motion to be transmitted from the gear 66 through sleeve 67 to the rod 45 for adjusting the position of disc 46 (i.e. varying the distance L between disc 46 and 47).

In operation, upon application of hydraulic pressure to the valve 42, fluid will enter either above or below the piston of the hydraulic cylinder 14, say for example, above. Under the influence of this pressure the piston rod 15 and lever 17 will be move downwardly carrying the bosses 53 against the disc 47. This pushes the operating rod 45 and the valve operator 44 is moved to the bottom position switching the hydraulic pressure from line 62 to line 61 which leads to the lower side of cylinder 14. Now the piston 15 rises and so do the bosses 53 traveling through the distance L, minus the diameter D, to the disc 46. The operating rod 45 moves up with the disc 46 compressing spring 55 and retracting the valve operator 44 so that the fluid flow will again change directions. The mold stroke is proportional to the distance L so that by adjustment of the discs 46, 47, the stroke may be changed accordingly; the greater the distance L the greater the mold stroke and vice versa. This adjustment is accomplished by rotating the actuating rod 45 by means of the crank 39. Because the disc 46 is restrained from rotation by means of lug 51, the disc is moved toward or away from disc 47 on the threaded portion 48 of the operating rod 45. The crank 39 can be rotated at any time, including when casting is in progress and the mold is reciprocating.

The frequency of reciprocation is also adjustable by using a pump (not shown) with a variable displacement for pressurizing the hydraulic cylinder 14. Moreover, by merely replacing the hydraulic cylinder 14 with one having a different piston size ratio, the ratio of up to down speed can be varied.

As aforementioned, it is an important aspect of the invention that the design of the mold reciprocator provides one open side K for convenient exchange of the mold M from the side. Also, this design eliminates the problem of the mold seizing on its guides by permitting a single hydraulic cylinder to be used instead of two on opposite sides of the mold as in the prior art.

Having now described a preferred embodiment of the invention, it will be appreciated by those skilled in the art that certain modifications and changes may be made without departing from the invention as defined in the appended claims.

What is claimed is:

1. A mold reciprocator for a continuous casting comprising:

a pair of mold guides connected one on each side of the mold and mounted for reciprocal movement parallel to the mold axis;

an actuator means including an hydraulic cylinder drivingly connected through a lever to the mold guides for imparting a periodic time-displacement stroke thereto;

a pair of elements each having a contact surface and adjustable means for providing bidirectional adjustment of one of said elements relative to the other so as to permit the space between said contact surfaces to be selectively varied;

operator means connected to said actuator means for oscillating in proportion to the reciprocation of said mold, said operator means having a portion extending within the space between said elements for contacting said surfaces and causing a periodic displacement of said elements corresponding to the time-displacement stroke of said mold;

an actuator control valve means for controlling the supply of hydraulic fluid to said hydraulic cylinder; and

connecting means connected to said elements and said 5 6 actuator control valve means for operating said valve 3,042,326 7/ 1962 Lamb et al. 91-279 X means in response to movement of said elements. 3,088,181 5/1963 Littl'ewood et al. 164-261 2. A mold reciprocator according to claim 1 wherein 3,154,815 11/1964 Bieri 164-261 X said actuator means includes a U-shaped lever having its 3,258,815 7/1966 Reinfeld et al. 16483 X leg portions extending one on each side of the mold and 5 3,293,707 12/1966 Olsson 164-83 connected to the mold guides and pivoted on opposite sides of the mold, said hydraulic cylinder being connected FOREIGN PATENTS to the lever at the end opposite said mold guides. 1 1,040,273 3/1966 Great Britain- 3. A mold reciprocator as defined in claim 1 wherein 169,873 12/ 1959 Swedensaid connecting means comprises a rod member extending between said elements and threadedly connected to one 10 SPENCER OVERHOLSER, 'y EXamlIlef of said elements, one end of said rod being connected R SPENCER ANNEAR, Assistant Examiner to said actuator control valve means.

US. Cl. X.R. References Cited UNITED STATES PATENTS 1,142,551 6/1915 Burnhart 9l-279X