US2553946A

US2553946A - Machine for making foundry cores and molds

Info

Publication number: US2553946A
Application number: US72460A
Authority: US
Inventors: Herbruggen Heinrich Schulte
Original assignee: CONSTRUCTIONAL ENGINEERING COM
Current assignee: CONSTRUCTIONAL ENGINEERING Co Ltd; CONSTRUCTIONAL ENGINEERING COM
Priority date: 1948-03-11
Filing date: 1949-01-24
Publication date: 1951-05-22
Anticipated expiration: 1968-05-22
Also published as: GB637002A

Description

y 1951 H. s. HERBRUGGEN 2,553,946

MACHINE FOR MAKING FOUNDRY CORES AND MOLDS Filed Jan. 24, 1949 5 Sheets-Sheet l N VEN 7'0}? HEM/RICH SCHULTE HEABRwQBv HHOPHEYS May 22, 1951 H. s. HERBRU'GGEN 2,553,946

MACHINE FOR MAKING FOUNDRY CORES AND MOLDS Filed Jan. 24, 1949 5 Sheets-Sheet 2 May 22, 1951 H. s. HERBRUGGEN 2,553,946

MACHINE FOR MAKING FOUNDRY CORES AND MOLDS Filed Jan. 24, 1949 5 Sheets-Sheet 5 MNENTOR l/E/A/R/C say ULTE" HERBRUGQEA/ RTT R NEVS y 22, 1951 H. s. HERBRUGGEN 2,553,946

MACHINE FOR MAKING FOUNDRY CORES AND MOLDS Filed Jan. 24, 1949 5 Sheets-Sheet 4 HTTOKNEYS y 1951 H s. HERBRUGGEN 2,553,946

MACHINE FOR MAKING FOUNDRY CORES AND MOLDS Filed Jan. 24, 1949 5 Sheets-Sheet 5 INVENTOI? HEM/ m so /om? flRBRucae/v 3y rpm 6cm HTTOA/VEYS Patented May 22, 1951 MACHENE FOR MAKING FOUNDRY CORES AND MOLDS Heinrich Schulte Herbruggen,

Hagen-Kalle],

Germany, assignor to The Constructional Engineering Company Limited, Birmingham, v England, a company of Great Britain Application January 24, 1949, Serial No. 72,460

In Great Britain March 11, 1948 4 Claims.

This invention relates to improvements in machines for making foundry cores and moulds and refers particularly to machines or the type in which prepared sand is fed from a hopper or the like into a chamber from which it is forced by air under pressure through openings in the bottom of the chamber into a core box or moulding box which is supported on a table movable vertically by hydraulic or pneumatic means to hold the core box or moulding box against the blowing chamber for filling. A machine of this type is described in the specification of British Patent No. 570,193.

According to my invention a machine of the type set forth above comprises an intermittently rotated sand container, an intermittently operated shutter controlling the delivery of sand from the container to a blOWillg chamber, a table for supporting a core-box or mould to be filled, means for moving the table vertically to clamp the core box or mould against the bottom of the blowing chamber, pneumatic means for intensifying the clamping pressure on the core box or mould during filling, and a rotary control for controlling each of the operations or movements and for ensuring automatically that they take place in the correct sequence.

The control may be operated by hand or it may be operated by an electric motor with a pushbutton switch so that the machine is completely automatic and the operator has simply to place the core-boxes or moulds on the table and remove them at the appropriate times in the sequences of operations. 7

One practical form of machine for making foundry cores or moulds in accordance with my invention is illustrated. by way of example in the accompanying drawings in which- Figure 1 is a front elevation of the complete machine.

Figure 2 is a plan.

Figure 3 is a side elevation.

Figure 4 is an elevation on a larger scale and partly in section of the lower end of the machine showing the means for operating the ram and applying pressure to the core-box.

Figure 5 is a sectional elevation of the control mechanism for the machine.

Figure 6 is a horizontal section of the control mechanism.

In the machine illustrated the mainpart of the supporting frame consists of two rigid vertical columns IE, il. Mounted on the upper end of the frame at one side is the sand container 12 which is a cylindrical chamber mounted for ro- 2 tation about a vertical axis and divided by radial partitions ['3 into, say, six segmental compartments. The container is adapted to be rotated intermittently through a chain It and toothed ring l5 by an electric motor 36. The container is open at the bottom but is in contact with a circular plate ll having an opening I 8 leading into the blowing chamber I9. The opening I8 is controlled by an angularly movable shutter 29 operated by a pneumatic cylinder 2 I.

The blowing chamber is of the known type described in British patent specification No. 570,193 with means for supplying air under pressure to an air belt around the chamber, a wire gauze or like screen on the inner side of the airbelt, and a power driven agitator in the chamber. The agitator is driven through V belts 22 by an electric motor 2 5. Openings are provided in the bottom of the chamber for the discharge of the sand, the position and number of these openings depend ing on the type of cores or moulds to be made.

The blowing chamber has not been illustrated or described in detail as it is of known type.

The table 2 which supports the core-box or mould to be filled is mounted on the upper end of a ram 25 working in a vertical cylinder 26 which communicates with a pressure chamber 21 through a passage 28 controlled by a springloaded valve 29 as shown in Figure 4. This valve is urged towards its seating 30 by a spring 3! bearing against the bottom of the valve head but the valve is normally held open by a springloaded plunger 32 which enters the upper end of the chamber 2? and bears on the stem of the valve. v

Theplunger is guided in an extension 33 of a closure 34 bolted to and closing the upper end of the chamber 27, and a head on the upper end of the plunger carries a cup leather 35 working in an enlarged bore 35 in the closure. The cup leather is held between the head and a disc 31,

and springs 33 bearing on the disc normally hold the plunger in its lowermost position in which it holds the valve 29 open. The bore 36 below the cup leather is in communication with the interior of the chamber 2'! through one or more passages 39.

The chamber 21 is partially filled with oil and means are provided for admitting air under pressure into the chamber above the surface of the oil.

When the compressed air is admitted oil is forced from the chamber 21 into. the ram cylinder 26 by way of the valve 29 and passage 28, and the ram 25 and table 24 are raised to clamp a core-box or mould which has been placed on the table against the bottom of the blowing chamber l9. When the pressure in the chamber 2? reaches a predetermined value the spring-loaded plunger 32 is forced upwardly against the action of the springs 32 by the pressure acting on the plunger and on the underside of the head. The valve 29 then closes and seals the ram cylinder so that the table is locked in position.

To intensify the upward pressure on the table the upper part 46 of the table is allowed a limited vertical movement relative to the lower part and there is arranged between them a flexible diaphragm 6| of substantially the same area as the table. The periphery of the diaphragm is clamped between the lower part of the table and a clamping ring 42. The relative vertical movement of the upper part 46 of the table is limited by a sleeve 43 which surrounds the table. This sleeve has an engagement with a shoulder on the part 46 and near its lower end the sleeve carries an internal ring 44 between which and the lower part of the table there is a small ver-- tical clearance.

After the valve 29 closes air under pressure is admitted below the diaphragm 4i and owing to the relatively large area of the diaphragm the air applies a very high upward pressure to the table and so to the core-box or mould.

The various operations are controlled by a series of valves and switches which are mounted in vertical alignment in a casing 45 mounted at one side of the machine. Figures 5 and 6 show the arrangement of the control mechanism.

A main supply pipe 46 leads air under pressure from a compressor or other source to a central bore 41 in a hollow pillar 48 having four outlets controlled by valves 49, 50, 5| and 52. A parallel bore 53 in the pillar is also in communication with the valves and has connected to it an exhaust pipe 54 leading to atmosphere. One valve controls the supply of air to the blowing chamber 1 9 through a pipe 55, another controls the supply of air through a pipe 56 to the air cylinder 2| for the shutter 26, a third valve controls the supply of air through a pipe 5! to the space below the diaphragm 4!, and the fourth valve controls the supply of air through a pipe 58 to the pressure chamber 21.

Below the valves are two

electric switches

59 and 60 controlling respectively the energising of the motor I6 for driving the sand container and the motor 23 for driving the agitator in the blowing chamber.

The valves and switches are selectively actuated in the required order by cams 6| on a rotatable vertical spindle 62 provided at its upper end with a handle 63. The cams actuate the valves and switches through pivoted rockers 64 carrying rollers for engagement with the cams and the valves and switches to reduce friction.

The sequence of operations when the handle 63 is rotated step by step in one direction is as follows:

The motor I6 is switched on to rotate the sand container 12, and air is admitted to the cylinder 2| which opens the shutter 26 and allows sand to pass into the blowing chamber. The container is then stopped and the shutter is closed.

Air is admitted into the pressure chamber 21 to force oil out of that chamber into the ram cyl nder and raise the table 24 to clamp the corebox or mould against the bottom of the blowing chamber l9. When a predetermined pressure has been reached the plunger 32 is raised and 4 the valve 29 closes, and air is then admitted under the diaphragm 4| to intensify the upward pressure on the core-box or mould.

Next air under pressure is admitted to the blowing chamber and the agitator in the chamher is driven. After a predetermined time interval sufiicient to allow the core-box or mould to be filled, the air is cut oil from the blowing chamber and the agitator is stopped and the chamber is connected to exhaust to release the pressure.

The air feed to the space under the diaphragm 4| is then cut off and this space is connected to exhaust and the air supply to the pressure chamber 27 is cut off and that chamber is connected to exhaust. The pressure on the spring-loaded plunger 32 is thus relieved and the plunger opens the valve 29 between the ram cylinder and the pressure chamber so that oil can return from the ram cylinder to the pressure chamber and the ram and table can descend under gravity to allow the filled core-box or mould to be removed.

Preferably at the same time as the pressure in the pressure chamber 2'! is relieved the sand container is set in motion again and the shutter is opened to refill the blowing chamber, and the cycle of operations starts again.

To speed up

production sliding carriages

65, 66 may be arranged on opposite sides of the table of the machine and at the same level as the table in its lowered position, each carriage having wheels running on rails spaced apart at a distance greater than the width of the table. A core-box or mould is prepared on one carriage and the carriage with the core-box or mould on it is slid over the table which lifts the carriage off into rails and takes it up with the core-box or mould. Meanwhile another core-box or mould is being prepared on the other carriage, and after the first core-box or mould has been filled and the table has returned to its lowered position the first carriage is slid off to one side of the table and the second is slid on from the other side.

I claim:

1. A machine of the type set forth for making foundry cores and moulds comprising a sand container, a blowing chamber below said container, means for feeding sand intermittently from said container into said chamber, a table below said chamber for supporting a mould to be filled, an hydraulic ram on which said table is mounted and which is adapted to raise the table vertically to clamp the mould against the bottom of the blowing chamber, a passage connecting the lower end of the ram cylinder and a pressure chamber containing oil, means for admitting air under pressure to said chamber above the oil to force the oil into the ram cylinder, a springloaded valve in said passage, a pressure-responsive device within the chamber operatively connected with said valve, spring means acting on said device to normally move the latter to a position to open said valve, said device bein subjected to the pressure within the chamber and movable when a predetermined pressure is reached therein to allow said valve to close, and pneumatic means associated with said table for intensifying the clamping pressure on the mould when the valve is closed.

2. A machine of the type set forth for making foundry cores and moulds comprising a sand container, a blowing chamber below said container, means for feeding sand intermittently from said container into said chamber, means for feeding air under pressure into said chamber, a table below said chamber for supporting a mould to be filled, said table having a relatively movable upper part to receive the mould, a flexible diaphragm substantially co-extensive with the table between the table and the said relatively movable mouldreceiving part, an hydraulic ram carrying said table and working; in a vertical cylinder, a pressure chamber containing oil adjacent to the rain cylin a passage connecting the bottom of the ram cylinder and the pressure chamber, a spring-loaded valve in said passage, means for admitting air under pressure to said pressure chamber to force oil from the chamber through said passage into the rain cylinder to raise the ram and clamp the mould against the bottom of the blowing chamber, a pressureresponsive device within the pressure chamber operatively connected with said valve, spring means acting on said device to move the latter to a position to maintain said valve normally open, said device being subjected to the pressure within the pressure chamber and movable when a predetermined pressure is reached therein to allow said valve to close, and means for subsequently admitting air under the diaphragm to intensify the clamping pressure on the mould.

3. A machine of the type set forth for making foundry cores and moulds comprising a sand container rotatable about a vertical axis, electrical means for driving said container intermittently, a blowing chamber arranged below said container, pneumatically operated means for feeding sand intermittently from said container into said blowing chamber, a mould-supporting table below said blowing chamber, an hydraulic ram on which said table is mounted for moving said table vertically to clamp a mould against the bottom of the blowing chamber, pneumatic means for forcing oil from a pressure chamber into the ram cylinder, means including a device within the pressure chamber and subjected at all times to the pressure therein for closing the communication between the pressure chamber and the ram cylinder when a predetermined pressure is reached, pneumatic means associated with said table for intensifying the clamping pressure on the mould, grouped valves and switches for controlling the supply of compressed air and current to initiate the various operations of the machine, and a rotatable spindle carrying cams for actuating said valves and switches automatically in the correct sequence.

4. A machine of the type set forth for making foundry cores and moulds comprising a cylindrical sand container rotatable about a vertical axis, means for rotatin said container intermittently, a fixed plate over which said container works, blowing chamber arranged below said plate, an opening in said plate leading into said blowing chamber, a pivoted shutter for covering and uncovering said opening to control the delivery of sand from container int said blowing chniber, pneumatic means for operating said shut r, a supporting table below said blowing chamber, an hydraulic ram on which said table is mounted for moving said table vertically to clamp a mould against the bottom of the blowing chamber, pneumatic means for forcing oil from a pressure chamber into the ram cylinder,

means including a device within the pressure chamber and subjected at all times to the pressure therein for closin the communication between the pressure chamber and the ram cylinder when a predetermined pressure is reached, pneumatic means associated with said table and moving a part of said table relative to another part to intensify the clamping pressure on the mould during filling, and a rotary control for controlling each of the operations of the machine and for ensuring automatically that these operations take place in the correct sequence.

HEINRICH SCHULTE I-IERBRUGGEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 819,883 Hewlett May 8, 1906 1,030,326 Peterson June 25, 1912 1,563,156 Burman Nov. 24, 1925 1,781,168 Dollin Nov. 11, 1930 1,801,654 Blood Apr. 21, 1931 1,866,301 Goodlin July 5, 1932 1,940,063 Sherman Dec. 19, 1933 2,088,123 Toman July 27, 1937 2,192,133 Hagemeyer Feb. 27, 1940 2,300,148 Gilliland Oct. 27, 1942 2,409,330 Wood et a1 Oct. 15, 1946