Foundry core or mold making machine

This invention relates generally to a foundry blow mould or core making machine and more particularly to a machine which can quickly and efficiently produce cores or moulds of large size. The present invention represents certain improvements in mould and core blowing machines of the type seen in Elms U.S. Patent 3,089,205, Hatch U.S. Patent 3,253,304, and Janke U.S. Patent 3,613,770.

More particularly, the present invention adapts such machines for use with a gassing head such as employed in a cold box process utilizing S0₂ gas, for example.

In such process, the gas is employed to harden the sand which is mixed with approximately 1.2 to 1.5% phenolic or furan resin and peroxide in equal amounts to 25 to 40% of the resin.

In high production foundries it is important to be able to produce large and complex size cores or moulds in a minimal cycle time with repeatable accuracy. It is also important to be able to produce such cores with inexpensive and readily changeable tooling. In the cold box process such as that employed using S0₂ gas, the sand mix has the advantage of mixing in a conventional muller and it will not harden until gassed. With such process foundries can employ readily available tooling. Moreover, with the cold box process, metal tooling will not change in size because of the application of heat.

It is also important not only to be able to make the core or mould quickly, but to be able to deposit the core or mould on a conveyor for subsequent inspection and assembly without manual handling and without damage to the core or mould. Also, in job shop foundries where tooling changes frequently, it is important.to be able to employ a machine wherein the tooling can quickly and readily be inspected or removed and replaced if required.

According to the present invention there is provided a foundry blow mould or core making machine comprising a blow head, a frame located below the blow head supporting separable core or mould cope and drag box halves which are mounted on the frame for opening and closing movements with the cope box half being fixed to the frame and the drag box half being movable relative to the cope box half and at least partially rotatable when moved to position the drag box half to and from a mould or core discharge position, said frame being movable vertically to clamp the cope and drag box halves when closed against the blow head, characterised in that the machine includes a gassing head adjacent to the blow head, the gas and blow heads being movable between operative and inoperative positions, said frame extending transversely of the gas and blow heads and having a fixed pivot located at one end offset from the operative position of the gas and blow heads and means for vertically moving the frame about said offset pivot to clamp the cope and drag box halves when closed against the blow head or the gassing head when respectively located in the operative position.

An embodiment of the machine of the present invention preferably has a C-shaped frame with a gassing head and blow reservoir being supported side-by-side at the top of the frame for horizontal shuttling movement. A tooling frame extends generally horizontally of the machine and into the opening of the C. The tooling frame supports in a stationary manner the cope or fixed box half and in a movable manner the movable or drag box half which are clamped together in a plane extending vertically below the blow head or gassing head. The tooling frame is pivoted by a relatively short stroke vertically movable power actuator which pivots the tooling frame to clamp the box halves when closed against the blow head or gassing head.

The movable or drag box half is mounted on a cradle on the frame for movement toward and away from the cope or fixed box half and for pivoting movement to bring the box to a core or mould discharge or an inspection or disassembly position when the box halves are not clamped against the blow head or gassing head. Each box half includes a machine actuated stripping mechanism to ensure removal of the core both from the cope and drag with the latter then placing the core or mould on a discharge conveyor. The conveyor may be of the flat belt type serving a single machine or a series of machines and may be canted somewhat at the discharge position to present a flat face to receive the core or mould. The drag box half can be positioned and stopped above the conveyor belt to present the core of mould at an ideal discharge height. The pivot of the tooling frame is slightly vertically offset so as to present the top surface of the box halves in a horizontal plane for clamping.

An embodiment of the invention will now be described, by way of an example, with reference to the accompanying drawings, in which:-

• Figure 1 is a side elevation of a machine in accordance with the present invention;
• Figure 2 is an enlarged side elevation of the machine showing the tooling frame and the movable box in several of its available positions;
• Figure 3 is a top plan view of the machine;
• Figure 4 is a front elevation of the machine as seen from the line 4-4 of Figure 1;
• Figure 5 is a fragmentary vertical section through the box halves in their closed position illustrating the machine operated stripping mechanism utilized with the fixed box half;
• Figure 6 is a fragmentary transverse section through the movable box half illustrating the stripping mechanism employed at the discharge position; and
• Figure 7 is an enlarged horizontal section taken through the trunnion of the cradle of the movable box half as seen from the line 7-7 of Figure 1.

Referring first to Figures 1 to 4 it will be seen that the machine includes C-shaped side frame plates 10 and 11 which are interconnected near the bottom by base frames 12, 13 and 14 of the angle configuration shown. Projecting feet are provided at the corners of the base of the frame as seen at 15 so that the machine may be leveled and secured to the floor.

Also extending between the side frames 10, 11 are a structural rectangular tubular element 18, an angle frame member 19, and a cylindrical reservoir 20.

At the top the side plates 10 and 11 are interconnected by a head frame shown generally at 22 which includes transverse tubular frame members 23 and 24. Through the centre of the latter extends a tube 25 in communication with a blow valve 26 and an exhaust 27. The blow valve 26 is of course in communication with the reservoir 20 through the piping seen at 28.

Gussets 30 may be provided between the head frame 22 and the side frames 10, 11 to rigidifythe frame construction. Depending from the head frame 22 as seen more clearly in Figure 4 are brackets 32 supporting square section rails 33. The rails 33 in turn support V-groove rollers 34, four in number, two on each rail 33 which in turn support a shuttle carriage 35. The rollers 34 depend from a top plate 36 of the carriage 35 which includes a gassing head 37 and a sand blow reservoir 38. The sand blow reservoir 38 includes on its lower end a tapered yet laterally spreading bottom portion or nozzle 39 conforming the cylindrical configuration of the reservoir to the slot or blow holes in the top of the box halves clamped therebeneath. A seal assembly 40 is provided on the lower end thereof.

The carriage 35 is moved horizontally by a pneumatic piston-cylinder assembly 42, the piston rod of which is connected at 43 to the carriage 35. The piston-cylinder assembly 42 is trunnion mounted at 44 to a bracket assembly which extends from the head frame 22.

Immediately outside of the blow and exhaust valves, the head frame 22 supports a sand fill chute 47. The chute 47 is situated within a hood 48 which closes the top of the machine. Properly mixed sand for the core making operation may be fed through the chute 47. The chute 47 is normally closed by the top plate 36 when the reservoir 38 is in the blow position. Any sand spillage will be caught by the hood 48, or if not, will be caught by a deflector 50 to be moved laterally of the core or mould making operation.

It will be appreciated that the piston-cylinder assembly 42 shuttles the carriage 35 to and from a position in which the sand reservoir 38 is beneath the blow and exhaust valves and a position in which it is beneath the sand chute 47. When the reservoir 38 is beneath the sand chute 47, the gassing head 37 is in the position normally occupied by the sand reservoir 38.

Positioned below the shuttling carriage 35 is a horizontally extending tooling frame shown generally at 54. Seen more clearly in Fig. 3, the tooling frame 54 includes two side plates 56 and 57 which are pivoted at 58 and 59, respectively to the side plates 10 and 11. The side plates 56, 57 of the tooling frame 54 are interconnected by tubular frame members 62, 63 and 64 seen perhaps more clearly in Figure 5.

Of the three transverse frames 62, 63, 64 the frame 62 is the largest and is offset rearwardly from the other two vertically spaced frames 63 and 64. Secured to the lower side of the frame 62 at the centre are mounting brackets 66 for the trunnion support 67 of a piston-cylinder assembly 68.

The piston rod 70 of the piston-cylinder assembly 68 extends rearwardly of the machine and a reduced diameter end 71 thereof extends through a transverse yoke 72 and is secured thereto as seen at 73. Pivotally connected at each end of the yoke 72 are elongated trunnion links 75 and 76. The yoke 72, links 75 and 76, and the piston rod 70 project from the frame into a rearwardly projecting safety housing or hood 77 which is secured by suitable fasteners 78 to the edges of the side plates 10 and 11.

The trunnion links 75, 76 extend from the yoke 72 to trunnions 80 and 81 of a cradle 82 which supports the movable drag box half 83. The stationary or cope box half 84 is secured to a frame 85 mounted on the co-planar faces of the transverse frame members 63 and 64 as seen in Figure 5. Each trunnion link 75, 76 extends through a pair of vertically spaced stub shaft rollers as seen at 90 and 91 in Figure 3. Such paired rollers 90, 91 are secured to the inside of the side frames 56 and 57 of the tooling frame and maintain the trunnion links 75, 76 in proper alignment. Each trunnion link 75, 76 is also provided with two side guide rollers as seen at 94,95 and 96, 97, respectively.

As seen more clearly in Figure 7, such rollers 94-97 are mounted on brackets 99 secured by fasteners 100 to the top of the trunnion links 75, 76. The rollers 94-97 ride or bear against the inside surface of the side plates 56 and 57 of the tooling frame. Thus, the paired rollers 90 and 91 maintain the trunnion links 75, 76 in proper alignment with the tooling frame while the rollers 94 through 97 maintain the proper spacing of the links 75, 76 between the side plates 56, 57 of the tooling frame. Such rollers 94-97 may be of the type manufactured and sold by The Osborn Manufacturing Corporation of Cleveland, Ohio under the trademark LOAD RUNNERS.

As seen perhaps more clearly in Figure 7, each trunnion link 75, 76 extends into a slot 102 in the cradle 82 and is journaled on trunnion 80 or 81. Each trunnion 80, 81 includes an outwardly projecting roller as seen at 103 which rides with a slot 104 in the respective side plate 56, 57. The configuration of the slot 104 is seen more clearly in Figures 1 and 2. The slot 104 includes a semi-circular portion 105 which extends around an inwardly projecting roller 107. Each inwardly projecting roller 107 rides in linear slots 108 which extend parallel to and in line with the straight portion of the slot 102. Thus, as the cradle moves to the right, as seen in Figures 1 and 2, the cradle will be supported with the rollers 107 and 103 aligned in the direction of movement until the roller 103 enters the semi-circular portion 105 of the slot 102 thus pivoting the cradle downwardly about the axis of the rollers 107. Continued movement of the cradle to the right as seen in Figures 1 and 2 will cause the cradle to pivot substantially through 180° with the roller 103 being then at the end of the slot 102 and on the opposite side of the roller 107.

It is noted that the side plates 56, 57 of the tooling frame include an upwardly offset portion 110 at the proximal end which offsets the pivots 58 and 59 to be substantially horizontally aligned with the top surfaces of the box halves 83 and 84 when they are clamped together and upwardly against either the sand reservoir or the gassing head.

Referring now to Figure 5, it will be seen that the frame 85 supporting the fixed box half 84 includes two horizontally spaced frame plates 112 and 113, the former being open. Between such frame plates 112,113 is accommodated a stripper plate 114 to which are secured stripper pins 115. Also secured to the stripper plate 114 are four stripper plungers 116 which when the box halves are open project slightly beyond the face 117 of the fixed box half 84. The end of each plunger 116 is enlarged and a compression spring 118 is situated between the enlarged end and the plate 113. Thus, as the box halves close together to the position seen in Figure 5, the compression springs 118 are compressed. This moves the stripper pins 115 to a position in which they are flush with the surface of the cavity 120 as shown. When the box halves 83, 84 separate, the compression springs 118 move the plungers 116 and thus the plate 114 as well as the stripper pins 115 outwardly or to the right as viewed in Figure 5. The pins 115 thus eject the core from the cavity 120 of the fixed box half 84.

At the lower end, the frame plate 112 projects beyond the transverse frame 64 and is rigidified thereto by a gusset 122. Secured to the face of the depending projection of the frame 112 is a block 123. The face of the block 123 is provided with an inverted T-shaped spacer 124 which is held in place vertically by a key 125. Trunnion blocks 126 are secured to the block 123 through the spacer 124 by suitable fasteners passing through apertures 127.

Situated between the trunnion blocks 126 is an eye 130 connected to the rod 131 of a relatively short stroke piston-cylinder assembly 132. The eye 130 is pin connected to the trunnion blocks 126 as indicated at 133.

The piston-cylinder assembly 132 is trunnion mounted at 135 to trunnion blocks 136 and 137 secured to the face of the rectangular transverse frame member 18. In this manner, the tooling frame 54 may be pivoted about the pivots 58 and 59 by extension and retraction of the piston-cylinder assembly 132.

Referring now to Figures 1, 4 and 6, it will be seen that the cradle 82 is hollow and supported in the hollow portion 140 is a stripper plate 141. The stripper plate 141 is secured at 142 to one end of plungers 143 which are mounted in bushings 145 and 146. Each plunger 143 is provided with a shoulder as seen at 147 and a compression spring 148 extends between the shoulder 147 and the flange of bushing 146. There may be four such plungers 143 supporting the stripper plate 141 at each corner.

The drag includes stripper pins 150 normally ,flush with the interior surface 151 of the drag. Each stripper pin 150 is provided with a head 152 normally slightly out of engagement with the plate 141.

Situated within the hollow 140 are two rocker arms 155 pivoted centrally at 156 to brackets 157. Ball contacts 158 and 159 may be secured to each end of the rocker arm 155. The ball contacts 159 are designed to engage the centre line of the stripper plate 141.

Each other ball contact 158 engages the top of plungers 162. Each plunger 162 includes an enlarged end mounted in bushing 163 and a reduced end mounted in a plunger retainer 164. The reduced shank of the plunger 162 is sealed in the retainer 164 as seen at 165. The plunger 162 is hollow and internally threaded to receive an adjustable contact stud 167. Lock nut 168 holds the stud 167 in the adjusted position. The head 169 on the lower end thereof is designed to contact one of the projecting brackets 170 extending from transverse frame 19 as seen more clearly in Figures 1 and 4. As the cradle 82 moves downwardly in the inverted position as seen in Figure 6, the heads 169 contact the brackets 170 elevating each plunger 162 thus rocking the arms 155 and depressing the plate 141 against stripping pins 150 causing them to eject the core or mould onto the surface 17.2 of a conveyor 173.

As seen more clearly in Figures 1 and 4, the side frames 175 and 176 of the conveyor 176 are mounted on C-shaped brackets 177 and 178 which are pivoted at 180 and 181, respectively to the insides of the side plates 10 and 11 of the machine frame. Each bracket 177, 178 includes a depending arm rigidly secured thereto as seen at 182 and 183 and the angular position of such arms 182,183 and thus the brackets 177, 178 may be adjusted by the adjustment mechanisms seen at 184 and 185 so that the conveyor 173 may be tilted or canted.

Since the cradle 82 supporting the movable drag box half moves downwardly about the pivot 58, with certain deep cores, it may be advisable to tilt the conveyor 173 to position it parallel to a surface of the core and to assure clearance when the cradle is elevated in its arcuate path about the pivot 58. In any event, the core is deposited on the conveyor 173 in its selected position. It will be appreciated that the conveyor 173 may extend through and service a plurality of machines.

As seen more clearly in Figure 2, the piston-cylinder assembly 68 may be fully retracted to the extreme limit of slot 104. This positions the box half, with or without the core or mould, in the phantom line position 190 facing horizontally outwardly. In this position the box or core or mould may be inspected or the latter may be manually removed. Such position also facilitates removal and replacement of the tooling. In the clamped together position of the box halves, the fixed box half may be removed from its frame 85 by loosening the hexagonal nut and pivoting the swing bolts 188 seen in Figure 7 at four places through 90°. Plate 114 with the stripping pins 115 attached, are part of the core box. The box halves are then secured together by straps or special fasteners and then both are moved to the position 190 for removal. The process is reversed for replacement.

Operation

The cycle of the machine is briefly as follows. The relatively large piston-cylinder assembly 68 and the relatively short stroke piston-cylinder assembly 132 may both be hydraulic. With the piston-cylinder assembly extended clamping the box halves together and with the sand reservoir 38 in position above the parting plane of the boxes, the piston-cylinder assembly 132 is extended to clamp the closed box halves against the blow reservoir. At this point the blow valve 26 is opened followed immediately by the opening of the exhaust valve 27. The box halves with the sand resin mixed therein is then lowered slightly by partial retraction of the piston-cylinder assembly 132. The pneumatic cylinder 42 is now extended substituting or shuttling the gas head into position above the box halves while at the same time shuttling the sand reservoir to a position beneath the fill chute 47. The boxes are then again elevated by extension of the piston-cylinder assembly 132 to clamp them against the gassing head. At this time the curing gas such as the aforementioned S0₂ is forced into the sand resin mix, and is purged. Also at the same time the sand is fed through the chute 47 into the reservoir 38.

After the curing of the core, the still clamped together box halves are lowered slightly by partial retraction of the piston-cylinder assembly 132. At this time, the piston-cylinder assembly 68 now retracts moving the cradle 82 to the right. As the box halves separate the stripping mechanism seen in Figure 5 causes the stripping pins 115 to follow the box half 83 causing the core or mould to remain in the cavity 151 of the drag half. Continued movement of the drag half away from the cope clears the core or mould therefrom and further movement rotates the cradle and the movable box half about the roller 107. When the cradle achieves its inverted or downwardly facing position moving to a pre-determined height above the discharge conveyor 173, the piston-cylinder assembly 132 is then hydraulically locked until the core or mould is discharged. Figure 6 shows the plunger studs 167 contacting the brackets 170 causing the plate 141 to move downwardly stripping the core from the drag half of the box onto the top surface 172 of the conveyor 173. Again, depending upon the particular core employed, the conveyor 173 may be tilted at a slight angle to receive the core. After the core is mechanically ejected, the piston-cylinder 132 partially elevates. The piston-cylinder 42 retracts moving the blow reservoir into place. The piston-cylinder assembly 68 then extends closing and firmly clamping the box halves together. Then further extension of the cylinder 132 clamps the closed box halves against the blow head to repeat the cycle.

In any event, with the present invention, large cores or moulds can be made with a cold box process in a cycle time of approximately 12 seconds.