US2961721A

US2961721A - Machine for making hot tops for ingot moulds

Info

Publication number: US2961721A
Application number: US708630A
Authority: US
Inventors: Tiberg Magnus George; Kjellberg Sven Axel
Original assignee: Svenska Kullagerfabriken AB
Current assignee: SKF AB
Priority date: 1957-01-14
Filing date: 1958-01-13
Publication date: 1960-11-29
Anticipated expiration: 1977-11-29

Description

Nov. 29, 1960 Filed Jan. 13, 1958 M. G. TIBERG ETAL 2,961,721

MACHINE FOR MAKING HOT TOPS FOR INGOT MOULDS 3 Sheets-Sheet 1 mvcmoas: MAGNUS GEORG TIBERG SVEN AXEL KJELLBERG ATT VS.

Nov. 29, 1960 M. s. TIBERG ETAL 2,961,721

MACHINE FOR MAKING HOT TOPS FOR INGOT MOULDS Filed Jan. 13. 1958 3 Sheets-Sheet 2 mvau'roasz MAGNUS GEORG TIBERG BY SVEN AXEL KJELLBERG WW ATTYS- Nov. 29, 1960 M. G. TIBERG Erin. 2,951,721

MACHINE FOR MAKING HOT TOPS FOR meow MOULDS Filed Jan. 13, 1958 3 Sheets-Sheet 3 INVENTORS. MAGNUS GEORG TIBERG SVEN AXEL KJELLBERG Mg W ATTYS.

United States Patent MACHINE FOR MAKING HOT TOPS FOR INGOT MOULDS Maguus George Tiberg and Sven Axel Kjellberg, Halleors, .Sweden, assignors to Aktiebolaget Svenska Kullsavgeafabriken, Goteborg, Sweden, a corporation of e en 1 :Filed Jan. 13, 19 s, Ser. No. 708,630

Claims priority, application Sweden Jan. 14, 1957 s Claims. 01. 22-49 The present invention relates to a machine for making hot tops especially those which are intended to the applied to ingot moulds for making killed ingots. A suitable hot top may comprise a body of fire-proof material, preferably fine sand, having a silicate binder such as sodium silicate and/or potassium silicate, the sand being of such degree of coarseness that the body can be formed by a vibrating process while still being porous after drying and which has a downwardly extending portion for projecting into the ingot mould. In the fire-proof material the size of the largest grain should not exceed 5 mm. and the average size should be about 0.4 to 2 mm. In other words, all the grains should pass through a screen with ,5 mm. mesh and the greater part should be within the limits 0.4 to 2 mm.

' The quantity of binder should be 5 to 15% by volume,

suitably about by volume of waterglass of about 38' to .40 Baum calculated on the volume of the dry material, In the finished hot top this will correspond to a sodium silicate or potassium silicate content of.1.7 to 5.2% by weight calculated on the weight of the dry ma-. terial.

Thevolume of the wall of the hot top should be as small'aspossible. It may .thus be less than .the volume which it envelops. Excellent results have been obtained when the volume of the wall was 50% of the volume enyeloped.

A hot top of this kind could be made in a core blower and hardened in the machine in a known manner with carbonic acid, but this decreases its strength so that it will .not be'strong enough after drying. If the hot top is to remain intact after being moulded without carbonic acid hardening it is necessary to use a hard sand, i.e. a wet'sand. The finished .top will then have a tendency to crack when the steel is poured into it and will thus be useless.

' The present invention has for its purpose to avoid these .difliculties.

, The machine according to the present invention is characterized mainly by an outer pattern for moulding the outer surface of the hot top, an inner pattern for moulding the inner surface of the hot top, a lower pattern for moulding its ,lower portion, said patterns together enclosing a space to form a mould for the hot top and being separable in a vertical direction relative each other, means for mechanically moving at least two of the said patterns in a vertical direction for closing and separating the patterns, there being a feed hopper for supplying .material to the said mould, at least one of the said patterns being "Ice connected to a vibrator for imparting vibrations thereto, means for moving the lower pattern in a substantially horizontal direction and means for closing olf the upper edge of the box.

The means for closing off the top may suitably be made on the principle of a camera diaphragm and have a pneumatically driven piston device for cutting off the top. It also serves to cut off the supply of mixture to the machine. At the beginning of the next cycle the closing ofi means is opened with the aid of the same device and may suitably be located between the feed hopper and the outer pattern. The lower pattern is movable in a substantially horizontal plane before and after the moulding operation. It is intended to mould a downward extension on the hot top for projecting down into the ingot mould and the hot top will remain resting on this part even after the operation in the machine has been completed. These lower patterns may be provided with wheels and may be movable on rails, on conveyors, carriages or in any suitable manner.

To prevent the mixture which is very sticky from adhering to the machine parts with which it comes into contact these parts are coated with a suitable material with a low coefficient of friction, e.g. polymerized tetrafluoroethylene or, alternatively, suitably located nozzles may be provided to spray water onto the inner and outer patterns when the latter are in suitable positions. Still further characteristics of the machine will be apparent from the following detailed description of a form thereof.

In order to explain more clearly the manner in which the machine operates the method of making a hot top in the machine is described in the following with reference to the accompanying drawings in which Fig. 1 shows a section through a hot top made in a machine ac cording to the invention. Fig. 2 shows a plan view of thesame hot top. Fig. 3 shows a section through a machine according to the invention. Fig. 4 shows the closing off means for separating the hot top from the mixture. Fig. 4-11 is a fragmentary enlarged sectional plan view of the closing-oil" device illustrated in Fig. 4, showing the closing-01f elements retracted. Fig. 4b is a fragmentary enlarged sectional plan view of the closing-0E device showing the closing-oil? elements advanced to cutoff position, and Fig. 5 shows the sequence of operations when making a hot top. 7

Figs. 1 and 2 show a hot top 1 applied to'an ingot mould 2; The upper part of the mould is substantially square with rounded corners. At two opposed sides of the mould are lugs 3. The lower part of the top is shaped to fit the mould and is extended downwards sothat an extended portion 4 projects into the mould. Between the inner surface of the mould and the outer surface of the portion 4 there will be a small interstice 5. This interstice is filled with a sealing substance. The top tapers olt upwardly and its upper part is circular. A spring 6 is wound round the top at about half its height and encircles the top 1 /2 times and is extended to grip the lugs 3.

Fig. 3 is a section through a machine for making hot tops according to the invention. The top is formed between an outer pattern 7, an inner pattern 8 and a lower pattern 9.

- The. outer pattern 7 can be raised and lowered together with a feed hopper 10 by means of a bar 11 and a pneumatically operating piston in a cylinder 12. It is guided by rollers 13. A cone 14 is located within the feed hopper 10. A discharge pipe 15 is arranged above the feed hopper 10 for filling material into the hopper. The lower end of the hopper can be closed by a cutting off device 16 which is shown more clearly in Fig. 4. The hopper may suitably be coated with polytetrafluoroethylene.

The inner pattern 8 is carried by a bar 17 and can be raised and lowered in a similar manner by means of a piston pneumatically operated in a cylinder 18. A vibrator 19 is located under the pattern 8. The pattern 8 is provided with a shoulder against which the cone 14 rests.

The lower pattern 9 comprises a frame member formed from a Z-shaped profile bar and having rollers 20 for rolling on a track 21.

Fig. 4 shows the closing off device 16 which resembles the diaphragm of a camera. It cuts off the flow of niaterial from the hopper and after completion of the moulding separates the hot top from material remaining in the hopper. The closing off device comprises an outer ring 22 and an inner ring 23 which latter consists of a number of segments pivoted in the ring 22 at 24. The closing off operation is accomplished with the aid of a pneumatic device which actuates the ring 22 through an arm- 26 and a link 27. The ring is thus rotated thereby turning the segments and decreasing the diameter of the opening to cut off the flow of material.

This closing-off device is illustrated in greater detail in Figs. 4-a and 4-1). These figures show the overlapping segments 36 pivoted on pins 35 on the inner ring 23. The inner edges of the segments are formed on two

arcs

37 and 38, respectively. When the segments are in the retracted or inoperative positions as shown in Fig. 4-0, the arcs 37 of the segments jointly form a circle which corresponds to the inner peripheral surface of the hopper 10, as also shown in Fig. 3.

When the segments are advanced to the operative position, as shown in Fig. 4-b, the arcs 38 form a circle smaller than the aforesaid circle formed by the arcs 37, and conforming in size to the circumference of the upper end of the cone 8, again with reference to Fig. 3. Thus in the retracted position of the segments 36, the top of the mould cavity is open to the hopper, and in the advanced position, the segments act to close the opening, and in the process of advancement, to sever or to separate the material in the mould cavity from the material in the hopper.

As previously explained, the segments are advanced and retracted by rotating an outer ring 22 through the medium of the arm 26 by action of the pneumatic cylinder 25, which contains a plunger connected by link 27 to the arm. Each of the segments is connected to the ring 22 through the medium of a pin 24 on the ring, which is received in a slot 39 in the segment. The inner ring is fixed through the medium of arm 41 extending inwardly from the fixed frame of the apparatus.

Fig. shows the sequence of operations for making the hot top. A drying furnace is designated 28. The dried hot tops are transported from the end 29 of the furnace while resting on the lower pattern 9 which rolls on wheels 20 on a track 21.

The next operation takes place at 30 where the hot top is removed and the lower pattern is cleansed and may also be provided with a thin protective coating of gypsum. The removal is facilitated thereby that the lower pattern can be opened up by means of a handle 33. The empty lower pattern is then rolled in under the machine at 31. After a new hot top has been moulded the lower pattern is transported to the furnace 28 as shown at 32.

The moulding of the hot top is carried out as follows. From an elevated container (not shown) material is led through the discharge pipe 15 to fill the hopper 10 which, together with the outer pattern 7 is then in upper position. The cutting off device 16 is closed and rests against the cone 14. At the same time the lower pattern 9 is centered over the inner pattern 8 which is at the time in its lower position. The inner pattern 8 is then raised and the hopper 10 and the outer pattern 7 are lowered. The inner pattern 8 continues its movement until its top enters the cone 14 after which the latter will rest on a shoulder on the inner pattern. At the end of its downward movement the outer pattern rests on the lower pattern. The lower pattern is positioned thereby that it is located by the inner pattern and the latter in turn is guided by the cone which is fixed to the hopper and the outer pattern. The closing off device is now opened and material falls quickly from the hopper into the space formed by the inner, outer and lower patterns and the vibrator is started. The vibrator is allowed to run for a suitable length of time after the moulding space has been filled. The closing off device is now closed, the outer pattern raised and the inner pattern lowered, whereby the finished hot top remains resting on the lower pattern. This is transported away, preferably direct to the furnace. The cycle is repeated for the next hot top.

It has been found that the whole cycle takes about 20 seconds. The lower patterns move along a closed circular track about which furnaces are arranged. The furnace may have a capacity of for instance of about 75 hot tops per hour and the operations of the machine are regulated to coincide therewith. About 25 lower patterns will thus be required which circulate along the closed track through the machine and the furnaces.

The removal of hot tops from the lower pattern after they have been dried can also be accomplished automatically for instance by means of an arm with suitable gripping members, which lift the top from the pattern to a suitable transporting device and the machine and the furnaces can thus be made to operate wholly automatically without special attendance.

If greater capacity is required the machine may be made with several moulding units working at the same time.

We claim:

1. A machine for making hot tops for ingot moulds comprising an outer pattern for moulding the outer surface of the hot top, an inner pattern for moulding the inner surface of the hot top, a lower pattern for moulding its lower portion, said patterns together enclosing and defining therebetween a space to form a mould for the hot top and being separable in a vertical direction relative to each other, means for mechanically moving at least two of the said patterns in a vertical direction for closing and separating the patterns, a feed hopper for supplying material to the said mould a vibrator connected to, at least one of the said patterns for imparting vibrations thereto, means for moving the lower pattern in a substantially horizontal direction and means selectively operable for closing off the upper end of the mould.

2. A machine according to claim 1 wherein the outer pattern is movable upwards, the inner pattern is movable downwards and the lower pattern is movable sideways from the closed position in which they together form the mould.

3. A machine according to claim 2 wherein the closing olf device is located between the hopper and the outer pattern. a v v 4. A machine according to claim 2 wherein the] inner pattern engages a conical hood within the hopperwhen the inner pattern is in raised position and the outer pattern is in its lower position. Y

5. A machine according to claim 3 wherein the closing off device comprises an overlapping annular series of seg mental plates embracing the upper end of the mould, and means for simultaneously adjusting the plates to close oif and to open the said upper end of the mould selectively.

6. A machine according to claim 1 wherein the closing-off device is located between the hopper and the outer pattern.

7. A machine according to claim 1, wherein the inner pattern engages a conical hood within the hopper when the inner pattern is in raised position and the outer pattern is in its lower position.

8. A machine according to claim 3 wherein the inner pattern engages a conical hood within the hopper when the inner pattern is in raised position and the outer pattern is in its lower position.

References Cited in the file of this patent UNITED STATES PATENTS 1,698,603 Moore Jan. 8, 1929 1,911,011 Brotz May 23, 1933 2,789,332 Scott Apr. 23, 1957 2,846,739 Hallsworth Aug. 12, 1958 FOREIGN PATENTS 549,957 Canada Dec. 10, 1957 ERNEST w. SWIDER Attesting Officer UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No. 2,961,721 November 29, 1960 Magnus Georg .Tiberg et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the grant, line 1, and in the heading to the printed specification, line 4, name of first inventor, for "Magnus George Tiberg", each occurrence, read Magnus Georg Tiberg 1 Signed and sealed this 16th day of May 1961.

(SEAL) r Attest: 1

DAVID L. LADD I Commissioner of Patents