DE2943453A1 - CONVERTIBLE MACHINE FOR THE PRODUCTION OF SAND CORES - Google Patents

Description

The present invention relates to a convertible sand core machine for making rigid sand cores for use in metal casting. In a special aspect, the invention relates to a convertible machine for the production of sand cores by the hot box method with horizontally and vertically divided core boxes.

Machines for the production of sand cores for foundries process a molding mixture of sand into which a relatively small amount of a binding agent is mixed. This molding sand mixture is filled into a core molding box made of iron or another metal, the inner shape of which corresponds to that of the object that is to be produced with the sand core.

One known method of making rigid sand cores is known as the hot box method. In this process, the core box is inserted into the core machine and a molding mixture of sand and a hardenable binder is blown into the core box. The curable binder such as a thermosetting resin polymerizes when heated and thus hardens the molding sand mixture. After the molding sand mixture has hardened, the core is removed from the machine for use in metal casting.

A special application of the hot box process is the production of shell sand cores, i.e. H. of hollow rigid sand cores. The molding sand mixture is filled into a core or molding box made of iron or another metal, the inner shape of which corresponds to that of the sand core to be produced with the sand core, and the core box is then heated to a predetermined temperature that is high enough for a layer to form the molding sand mixture forms in the required thickness on the inner surface of the core box. This layer is partially hardened by the initial heat imparted to the core box; the molding sand mixture is then poured out of the core box by turning it over. The layer or shell of the molding sand mixture is then further heat treated in order to harden it and is finally removed from the core box and used as a core in metal casting. Examples of this pot core process are described in U.S. Patents 3,511,302 and 2,855,642.

Various machines are currently available for producing rigid sand cores using the hot box method; some of them work independently. An example of such a machine is the automatic pot core machine HS-16-RA, Redford Bulletin No. 704, the Foundry Products Division of International Minerals & Chemical Corporation. This machine can also be used to automatically produce hot-box sand cores. Recently, US Pat. No. 4,082,134 disclosed a sand core machine which can be used for the cold or hot box process, including the manufacture of pot cores. This machine is also manufactured by the Foundry Products Division of International Minerals & Chemical Corporation, Detroit, Michigan, V.St.A.

One difficulty with this sand core process arises from the shape of the core. The core box is designed in such a way that it can be split in half and the sand core can be removed after the resin has hardened. Depending on the shape of the core, the core box is opened or divided vertically or horizontally. So far, there is no machine that can accommodate both types, so the foundries had to invest in two machines - one for vertically and one for horizontally dividing boxes.

It is therefore an object of the present invention to provide a single convertible machine that can be used both vertically and vertically can accommodate horizontally divided core boxes for the hot box process. This machine eliminates the need to have two machines on hand.

1A and 1B of the drawings show, as a partially sectioned front view, an arrangement according to the present invention for operation with vertically divided core boxes;

2 shows the bearing or the carrier for horizontally divided core boxes, assembled and ready for operation;

3 and 4 show exchangeable heads for filling the sand-binder mixture into the core box, FIG. 3 showing the cooled magazine head for vertically divided boxes, FIG. 4 the magazine head and the cooled plate for horizontally divided boxes.

Fig. 5 shows the heat distributor for horizontally divided core boxes.

The present invention is directed to a sand core machine which can be converted from core production with horizontally divided core boxes to core production with vertically divided core boxes and vice versa and which has an output device such as a funnel and a magazine for outputting a mixture of molding sand and a binding agent for this a magazine head and a blower plate in a core box, means for hardening a core in the core box by adding the molding sand-binder mixture is cured, and has interchangeable parts suitable for use with horizontally and vertically split core boxes, these parts being (a) a water-cooled magazine head with a blow plate which is connected to the molding sand-binder magazine and to can create a vertically divided core box, whereby this magazine head can be exchanged for (b) a magazine head with a water-cooled blower plate, which can be arranged on the molding sand-binder magazine and can be placed against a horizontally divided core box, (c) a heat distributor for the upper part of the box as well as an upper part ejection head, which can lie against a horizontally divided core box, (d) a sand return device which is movable in order to be able to be brought into its desired position, (c) a detachable, vertically arranged support arrangement or box holder with a core box clamping device that are placed against a horizontally divided core box d can support it and has a heat distributor for the lower part of the molding box, which rests against the bottom of the core box and can be removed if vertically divided core boxes are to be used, and (f) it is a removable, reversible support arrangement or box holder, which has one or more horizontally arranged clamping devices, which can rest against a vertically divided core box and support it, as well as a heat distributor.

The arrangement is controlled with electrical and pneumatic circuits, regardless of whether with vertical or horizontal divided molding boxes is worked, are executed the same. These circuits are known in the art and do not form part of the present invention; they are described, for example, in US Pat. No. 4,082,134. Furthermore, it should be understood that hydraulic circuits can also be used instead of pneumatic ones and are considered to be equivalent for these.

A summary of the basic steps of the shell process applied to shell cores is useful at this point for understanding the convertible core-making machine. The operator sets up the machine to work with a vertically dividing core box. The water-cooled magazine head assembly 24 (FIGS. 1 and 3) for a vertically divided core box is attached to the sand magazine assembly 2, the support assembly 7 is placed on the bearing columns 27, four of which are present, and the supports 28 (see FIG. 2) . Then the compressed air hoses are connected to the horizontal clamping cylinder 42 with quick-release couplings, the switches S4 to S12 and S14 are set to automatic mode and the corresponding interval lengths are set on the time control elements 1TR, 2TR, 3TR and 4TR, the setup switch S15 to vertical operation and the switch S16 to the Operating mode pot core production set.

The core box is introduced into the carrier assembly 7 and a coolant such as a gas or water is introduced through the magazine head sent. The gas burners 67, of which there is a large number, in the heating distributor 44 of the supports 30, 31 are ignited and the temperature adjusters TC1, TC2 are set to the desired temperature, which is detected by thermocouples; at the same time the control lamps PL3, PL4 light up. The operator then starts the automatic cycle by first pressing the main switch S1 (the control lamp PL1 lights up) and then simultaneously the two start switches S2, S3 (the control lamp PL2 lights up). This activates the horizontal box clamping device 42 which, controlled by the switch S4, clamps the vertically dividing core box in the carrier arrangement 7. The sand magazine arrangement 2 then swivels into its front position, since the sand magazine lever valve has been actuated with the switch S5. The vertical clamping cylinder is then actuated with the vertical clamping valve actuated by switch S9, so that the blow head is pressed onto the sand magazine arrangement 2 and the sand magazine arrangement in turn is pressed onto the core box. The blow valve controlled by switch S6, blow time adjuster TR1 and interval adjuster TR2 then become active. The blow valve 6 causes the sand-binder mixture to be blown from the magazine arrangement 2 into the core box. After the set blowing time has elapsed, the blowing pressure is released when a control valve is actuated. Then both the vertical clamping device 5 and the sand magazine arm arrangement 2 move back into the rest position shown in FIG. 1.

When the interval set on adjuster TR2 has expired, the drain time adjuster TR3 switches on and the carrier is turned over to pour out excess molding sand. The reversing device is operated with switch S11. Furthermore, the carrier arrangement is given a rocking movement in order to facilitate the pouring out of the molding sand into the return system 9. The oscillator 68 is, if desired, actuated automatically with the switch S8 in order to also support this process. The transducer can also be operated with an S17 foot switch. The sand-resin mixture flows into the return system 9 and is pneumatically returned to the funnel 3. The sand recirculation system is controlled with switch S14.

When the time period set on the drain adjuster has expired, the hardening time adjuster TR4 responds. The inverting mechanism and vibrator are stopped and the support assembly returns to its normal upright posture for the core to cure.

When the set hardening time expires, the horizontal clamping cylinder is de-energized and retracts. The core box opens; the automatic cycle has ended. The operator can now take the finished core out of the box. If necessary, she can use the foot switch to restart transducer 68 to facilitate core removal.

The automatic cycle can be interrupted at any time with an emergency switch S13.

Although the mode of operation of the machine for vertically divided core boxes has been described using the shell process, it can be seen that these processes also apply to the hot box process in the manufacture of solid, rigid cores. For this purpose, the operator sets the switch S16 (selector switch bowls / hot box method) to hot box method so that the turning process and shaking with the vibrator are not necessary.

If a horizontally dividing core box is to be used to manufacture solid, rigid cores, the operator converts the machine accordingly. The (Fig. 3) assembled for the vertically divided core box water-cooled sand magazine blow head assembly 24 is removed by loosening four bolts (see. The bolt holes 40 in Fig. 3) and the water connections 48, 49. Instead, one mounts the sand magazine head assembly 41 with the water-cooled blower plate (FIG. 4) for horizontally divided core boxes, as shown in FIG. 2, and the connections for the coolant - for example water or gas - are made. The gas connections to the heat distributors of the bearings 30, 31 are removed, as is the drive chain 51; the entire support arrangement for vertically divided core boxes can then simply be removed from the bearing pillars 27 and the supports 28. The sand return mechanism 9 is removed by loosening the pressure hose 65 and the sand return hose 66.

The mechanism can then be easily lifted out and set aside. The carrier arrangement 39 of FIG. 2 for horizontally divided core boxes is brought into the desired position and fixed by tightening the bolts 42 at the angles 70. The compressed air hoses are connected to the clamping cylinder 43, which moves the horizontal plate 71 on which the core box is placed up to the upper abutment plate 45. The horizontal abutment plate 45 and the core box are further supported by guide rods 46, four of which are present. The heating distributor 44 (FIG. 5) is connected to the heating gas source. The heating distributor 26 is fastened at this point in time with the bolts 80 (FIG. 2) and placed on the connection 72 on the gas line.

When ready for operation, the operator ignites the gas burners (not shown) in the heating manifolds 26, 43, sets the temperature adjusters TC1, TC2 to the desired temperature (with the pilot lamps PL3, PL4 lighting up), which is detected with thermocouples. Then he turns on the coolant flow through the blow plate.

The operator operates the switches including the main switch S1 (control lamp PL1 lights up) and the time adjusters required to control the process. She puts the switch S16 in the warm box position, the set-up switch S15 in the horizontal position and then presses the pushbutton switches S2, S3 (whereby the control lamps PL2 light up), thus initiating the automatic working cycle. The clamping cylinder

43 for the core box, which is operated with the switch S4, closes the core box. The sand magazine arrangement 2 runs in the front position directly over the closed core box and the vertical clamping cylinder 5 clamps the blow plate 25 firmly on the core box. Then the blow valve of the blow valve assembly 6 is actuated and blows sand-resin mixture from the magazine into the core box. If the blowing time control has expired, the blowing pressure is reduced and the vertical clamping device 5 and the sand magazine arrangement 2 move back. The filling time adjuster TR3 activates the vibrator on the sand funnel (not shown) and the magazine is filled for the next cycle. Then the right arm moves forward with the upper box heating distributor 26 and the upper box pushing device with pushing bolts and applies heat from above. The filling time control expires and the hopper vibrator is switched off.

If the hardness setting time has expired, the vertical clamping device pushes the upper box pushing bolts of the pushing device into the blow inlets of the top box under the control of the switch S9 with now reduced pressure. The core box tensioning cylinder 43 is relieved and the core box begins to open, with the core remaining in the lower box. The lower box pushing device (not shown) comes into operation when the core box clamping cylinder has reached the fully retracted position. The vertical clamping cylinder and the upper box push-off bolts then move back. Finally, the operator picks up the hardened core out of the box and the machine is then ready for the next work cycle or for conversion to operation with a vertically divided core box.

Fig. 1 shows the preferred embodiment of the convertible core machine according to the present invention. The control box 1 has numerous switches, buttons, control lamps and time control setting elements, which are arranged on the control box and are easily accessible to the operator; they are used to program the core machine. The construction of the control box and the programming of the machine are known from the above-mentioned US Pat. No. 4,082,134 and need not be described here.

A molding mixture of a heat-resistant granular material such as sand with a hardenable binder such as a thermosetting resin which is hardened by applying heat is filled in the sand hopper 3 before the core machine is started up. A vibrator (not shown) is attached to the funnel, which ensures an even flow of the sand-binder mixture.

Immediately below the sand funnel 3 in FIG. 1 is the sand magazine arrangement 2, which has a slide 23 which lets the molding sand mixture in the funnel mechanism 3 into the sand magazine arrangement 2. The molding mixture is contained in the sand magazine tube 11 which is connected to the blow head assembly 24. The magazine tube 11 is made up of the upper magazine arm 12 and a lower magazine arm

13 worn. The upper arm 12 is separated from the lower arm 13 by four collar shafts 14 which also carry the magazine guide ring 17. The sleeve 16 separates the guide ring 17 from the collar shaft 14. A spring 15 is placed around each of the shafts 14 between the guide ring 17 and the lower magazine arm 13. Since the magazine tube 11 is directly connected to the guide ring 17 carried by the springs 15, the sand magazine tube 11 and the sand magazine blow head 24 can move slightly vertically when the force is sufficient to compress the springs 15.

The parallel magazine arms 12, 13 are mounted in one end of the main shaft 18, which is connected to the bearing 19 of the core machine via the bracket 47. Since the upper and lower magazine arms 12, 13 are attached to the main shaft 18, the sand magazine assembly 2 can pivot in the horizontal direction from under the sand funnel 3 out directly over the core box, which is between the carriers 30, 31 (Fig. 1), the one can accommodate vertically dividing core box, or sits in a support assembly 39 (Fig. 2) which receives a horizontally dividing core box. The support assembly 7 as a whole is supported by the columns 27 and bearings 28 which in turn are attached to and supported by the frame.

The sand magazine assembly 2 is brought over the core box by actuating the magazine arm cylinder 22 which is controlled by compressed air from the control circuit in the control box 1. The working position is the same for vertically and horizontally divided core boxes. The magazine arm cylinder 22 is connected to the upper magazine arm 12 via the eye 21 and the fork head 20. The sand magazine arrangement 2 also has the blow head 24 and the blow plate 25; these are water-cooled and exchangeable and hold the molding sand mixture in the magazine tube 11.

The replaceable sand magazine head 24 shown in FIGS. 1 and 3 is designed for a vertically divided core box. It is interchangeable with a sand magazine head 41 and a water-cooled blow plate 79 for the horizontally divided core box shown in FIGS. The sand magazine head 24 and the blow plate 79 are provided with a water inlet 48 for connection to a water source and a water outlet 69 for draining the water. The sand magazine head 24 and the blow plate 79 of the head 41 are designed with channels through which water flows. The heads and blow plates also contain openings through which the sand mixture is blown into the core box. The pattern formed by these openings is determined by the shape of the core and is redefined for each core to be produced.

The heating manifold assembly 4 for the upper box, i. H. the upper half of the horizontally split core box is shown in FIG. 1B without the manifold 26 shown in FIG. The top box heater manifold assembly is essentially identical with the sand magazine arrangement 2 with respect to the magazine tube 11, the upper magazine arm 12, the lower magazine arm 13, the shafts 14, the guide ring 17, the guide sleeve 16, the guide ring spring 15, the magazine shaft 18, the bracket 19, the fork head 20 and the eye 21 Corresponding to the mode of operation of the sand magazine arrangement 2, the heating distributor arrangement 4 can be brought directly over the core box in the horizontal support arrangement 39. The horizontal movement of the heating manifold assembly 4 is controlled by the arm cylinder 29 which in turn controls the control circuit. The heating manifold assembly includes a heating manifold 26 (Fig. 2) which is connected to a fuel gas source. The temperature is controlled with the temperature setting TC1 in the control box and a thermocouple, not shown. The manifold assembly is provided with a top box kick plate (not shown) with top box kickers. Immediately before the core box clamping cylinder is switched off and the core box begins to open, the vertical clamping cylinder 5 automatically exerts pressure on the heating manifold assembly, as a result of which the pusher bolts press on the hardened sand in the core box, so that the core in the lower box, i. H. the lower half of the core box remains. If the machine is set up for vertically split boxes, the gas line at 72 is disconnected and the heating manifold 26 is removed.

The vertical clamping arrangement 5 is arranged above the sand magazine arrangement 2 and the heating distributor arrangement. The vertical clamping cylinder

5 is air operated and controlled by the control circuit in the control box. This arrangement pushes the blow head 32 onto the sand magazine assembly 2 and the sand magazine tube 11 and head 24 downwardly, compressing the magazine springs 15 when the sand magazine assembly 2 is below the vertical tension cylinder assembly 5 and above the core box. The force which the vertical clamping cylinder arrangement 5 exerts on the magazine tube 11 of the sand magazine arrangement 2 compresses the springs 15 and these arrangements from above onto the core box. After the heating cycle, the vertical clamping cylinder 5 is operated so that the pushing bolts push the core out of the upper box while the core box begins to open. The molding sand mixture located in the magazine tube 11 of the sand magazine arrangement 2 is filled into the core box when the sand magazine arrangement 2 is located directly below the vertical clamping arrangement 5. The molding sand mixture is transferred into the core box by compressed air which is blown through the molding sand mixture and pushes it through suitable blow holes in the blow plate 25. In addition, the compressed air distributes and compresses the molding sand mixture evenly in the core box. Compressed air from a compressed air source is forced through the sand magazine arrangement 2 with the blow valve arrangement 6. The blow valve arrangement 6 has the blow valve 33, a blow head 32 and a blow head discharge element 34. The blow valve 33 is operated with a compressed air control circuit, which in turn is triggered by the control circuit in the control box.

The vertically split core box according to the present invention is inserted between the left beams 31 and the right beams 30 of the assembly 7 which is attached to the frame 10. Each of these carrier arrangements has a bearing plate 35 which rests directly on the core box. The rear guide rods 36, of which there are two, and the front rod 38 support the beams 30,31. The beam 30 is movable inwardly horizontally along the guide rods 36,38 to define the core box between the beams 30,31. The movement of the carrier 30 is controlled by the horizontal clamping cylinder 37, which is actuated by the operator with pressure using pushbuttons on the control box and compressed air hoses on the horizontal clamping cylinder 37, which acts on the carrier 30.

The carrier 30 contains a heating manifold assembly 44 which is connected to the fuel gas line 72. The temperature is regulated with a temperature adjuster TC2 in the control box and a thermocouple lead at connection 73. The carrier 31 also contains a heating distributor 75 which is connected to the gas line 74 and is controlled by a temperature adjuster TC1 in the control box and the thermocouple feed line 76.

The details of the operation of the horizontal clamping device, the vertical clamping cylinder assembly 5 and the sand magazine arm cylinder 22 are described in US Pat. No. 4,082,134 and will not be repeated here.

The horizontal clamping cylinder 37 is connected to the main air supply via an air line and an actuating valve. By actuating the horizontal clamping cylinder 37 with compressed air, the carrier arrangement 7 can clamp the core box between the carriers 30, 31, as shown in FIG. 1. The operating valve for the horizontal clamping device connects the main air supply to the horizontal clamping cylinder 37 to push it inward. When energized, the actuating valve for the horizontal clamping device runs into the second position, in which the main air supply is applied to the horizontal clamping cylinder 37, so that it moves in the opposite direction. The actuating valve for the horizontal clamping device thus controls the direction of movement of the horizontal clamping cylinder 37. The vertical clamping device 43 operates in the same way.

The carrier arrangement 7 is connected to the frame 10 in such a way that, in the case of the pot-type core process, it can be turned over in the vertical as a whole, including the core box. In this way, excess molding sand mixture can be poured out of the core box during the pot core process. So that the carrier arrangement 7 can be turned around, a rolling mechanism 8 is attached to it. The drum 58 carries the carrier arrangement and enables it to be rotated, specifically with a chain 51 which runs over a gearwheel 56 which is connected to the gearwheel adapter 55 in the drum 58. The action of the chain 51 on the toothed wheel 56 is initiated by two cylinders 49 which are pneumatically operated.

The pressurization of the cylinders 49 is still controlled by the control circuit in the control box 1. The brackets 59 on both sides of the carrier arrangement support it by carrying the drum 58. The rotational movement of the carrier arrangement 7 is guided by a block bearing 60 which is fastened to the two ends of the carrier arrangement. In addition, stop cushions 61 are provided at both ends of the carrier arrangement; they prevent the carrier arrangement from overflowing the desired position. Furthermore, a spindle handle 50 is provided with which the separating surface of the core box can be aligned with the center line of the machine.

To detect the position of the carrier arrangement 7 during the turning movement, a cam disk switching mechanism 54 is provided which contains a multiplicity of electrical switches which are inserted into the control circuit; See US Pat. No. 4,082,134. A cam plate switch chain 53 is connected to the cam plate gear 52, which in turn is attached to the gear adapter 55 of the turning mechanism 8. The cam switch chain 53 is also connected to the cam switch gear 52. During the turning movement of the carrier arrangement 7, the chain 53 rotates the toothed wheel 52: the electrical switches contained in the cam disk switch mechanism 54 are actuated. The functioning of this mechanism 54 is described in US Pat. No. 4,082,134.

The core machine shown in FIGS. 1A, 1B also has a sand return system 9 with which excess molding sand is returned which was poured out of the core box in the pot core process with the turning mechanism 8. In the sand return system, a sand pan 62 catches the poured molding sand mixture. A piston bracket 63 carries a pressure shaft 64 which can be moved vertically upwards in order to close the opening in the sand pan 62. The pressure shaft 64 is actuated with the compressed air from the pressure hose 65. An actuating valve allows the return system to feed the molding sand mixture collected in the sand tub 62 back to the sand funnel mechanism 3 via the return hose 66, in that the pressure hose 65 is connected to a compressed air source. The compressed air in the pressure hose 65 pushes the pressure shaft 64 upwards so that it closes the sand pan 62 and then the molding sand mixture through the hose 66 back to the sand funnel mechanism 3. The actuating valve is automatically energized by the control circuit for its function within the sand recirculation system, as in FIG U.S. Patent 4,082,134.

The carrier assembly 39 for use with horizontally split core boxes is shown in FIG. It has a vertically arranged clamping device 43, which corresponds to the horizontally arranged clamping device 37 and is operated with the same compressed air system and the same switches. The carrier arrangement is located on a plate 77 which is fastened to the frame 10 with the angles 70 and bolts 42. Four guide rods 46 are arranged on the plate 77 and determine the upward movement of the bearing plate 71 when the clamping device 43 is actuated. A heat manifold assembly 44 having a plurality of burners such as shown in more detail in Fig. 5, is located on the plate 71, connected to the fuel gas line 74 and is controlled by the temperature adjuster TC1 in the control box and a thermocouple. The core box is placed directly on the heat distributor 44. If the clamping device 43 is operated with the control circuit, it lifts the core box until it touches the top plate 45; the springs 78 ensure that the upper case is in close contact with the plate 45. The machine then continues to operate as previously described. The sand magazine arrangement 2 pivots over the plate 45 and the vertical clamping cylinder 5 causes the blow head 41 to lie tightly against the plate 45, which contains blow holes which correspond to the blow holes in the upper box. Then the sand-binder mixture is blown into the core box; then the sand magazine arrangement 2 returns to the starting position. The heating distributor arrangement 4 swivels into the working position over the plate 45 and the sand core is hardened by the heat given off by the heating distributor 26 and the heating distributor 44. After the curing time has expired, the heating distributor arrangement 4 returns to the starting position and the core box opens, as described above.

Claims (1)

A sand core machine that can be converted from horizontal core production with horizontally divided core boxes to vertical core production with vertically divided core boxes with an output device that can output a mixture of molding sand and a binding agent for this purpose through a magazine head and a blow plate into a core box and has a heating device around the core to heat in the core box and thus to harden the molding sand-binding agent mixture, and with exchangeable parts for horizontally or vertically divided core boxes, whereby the exchangeable parts split core box and is interchangeable with (b) a magazine head with a water-cooled blower plate, which can be attached to the output device and can be placed against a horizontally split core box, (c) a heat distributor arrangement for the upper box, the sic h can be applied to a horizontally divided core box, (d) a sand return device which is movable to allow it to be set down in the target position, (e) a removable, vertically arranged support arrangement or box holder with a core box clamping device, which can lie against a horizontally divided core box and support it and has a lower box heating distributor device which can lie against the bottom of the core box, the carrier arrangement being removable for operation with vertically divided core boxes, and (f) a removable, rotatable carrier arrangement or box holder with a right and a left carrier, of which the right carrier can be moved on guide rods by a horizontally arranged clamping device which can rest against a vertically divided core box and support it securely, each carrier having a distributor-like heating device.