US3328852A

US3328852A - Foundry sand forming machines

Info

Publication number: US3328852A
Application number: US404397A
Authority: US
Inventors: Robert W Ellms
Original assignee: Osborn Manufacturing Corp
Current assignee: Osborn Manufacturing Corp
Priority date: 1964-10-16
Filing date: 1964-10-16
Publication date: 1967-07-04
Anticipated expiration: 1984-07-04

Description

July 4, 1967 R. w. ELLMS FOUNDRY SAND FORMING MACHINES 5 Sheets-Sheet 1 Filed Oct. 16, 1964 INVENTOR. ROBERT W. ELLMS BY agd.omaz

A TTORNEYS July 4, 1967 R. w. ELLMS 3,328,852

FOUNDRY SAND FORMING MACHINES Filed 0012. 15. 1964 5 Sheets-Sheet 2 INVENTOR. ROBERT W. E LLMS flmmgaameg ATTORNEYS July 4, 1967 R. W. ELLMS FOUNDRY SAND FORMING MACHINES Sheets-Shet 4 Filed Oct. 16, 1964 xmOu xmOm

mEFm mmOO m. 0 mQIO mosmmad 02E 10km INVENTOR. ROBERT W. ELLMS dlhiz/flw q 6311114211?! A TTOENEYS July 4, 1967 R. w. ELLMS FOUNDRY SAND FORMING MACHINES 5 Sheets-Sheet 5 Filed Oct. 16, 1964 INVENTOR. ROBERT W. ELLMS ATTORNEYS United States Patent 3,328,852 FOUNDRY SAND FORMING MACHINES Robert W. Ellms, North Olmsted, Ohio, assignor to The Osborn Manufacturing Company, Cleveland, Ohio, a corporation of Ohio Filed Oct. 16, 1964, Ser. No. 404,397 19 Claims. (Cl. 164-401) This invention relates generally as indicated to foundry sand forming machines and more particularly to automated foundry mold and core making machines.

In foundry molding machines, a vertically movable table is generally employed to assemble a pattern and flask which may be elevated conventionally by a hydraulic ram to an intermediate position at which the flask is filled with sand, struck ofi, jolted, etc., and then further moved upwardly against a squeeze head to ram the sand within the flask. The table is then lowered stripping the pattern from the mold and the formed mold within the flask is then moved to a core setting, mold closing and finally a pouring station. If the sand is to be blown within the flask, the table is still stopped at an intermediate position for the flask filling operation and when completed is then moved again upwardly to squeeze the sand within the flask against a squeeze head. Reference may be had to US. Patent No. 3,089,207 to L. F. Miller illustrating an exemplary type of hydraulically operated blow and squeeze foundry molding machine.

In core forming machines, a similar intermediate position is oftentimes required in the vertical stroke of a table or cradle supporting separable cope and drag parts of a mold box which is elevated against a blow head for introduction of sand within the box. The box may be heated to cure the resin-sand mix and is generally lowered away from the squeeze head to an intermediate position to permit a heating and punch out head to be placed thereover and after the core is sufficiently cured, the table or cradle is then lowered further to disassemble the mold box and strip the core therefrom.

While vertically intermediate precise positions are fairly easy to obtain with hydraulic equipment, because of the masses and short time cycles involved, such positioning of the mold box or flask is not as easily obtainable with pneumatic systems. More and more machinery manufacturers are switching to pneumatic operation of machinery because of the complexity and expense involved in hydraluic machines. Mechanical stops or latches limiting the strokes of large size pneumatic pistons may be provided, but these are subject to wear during repeated operation and are not sufliciently foolproof to obtain the desired degree of automation. Moreover, intermediate positioning devices must be able to take substantial stresses in view of the masses and movements involved as well as shock loads which may result from the jolting, sand filling, and like operations performed at such intermediate positions.

It is accordingly a principal object of the present invention to provide a simplified intermediate positioning device for foundry sand forming machines.

Another object is the provision of a pneumatically operated stop ring for use in foundry sand molding and core blowing machines by which an intermediate operational position can be obtained.

A further object is the provision of automatic sand forming machines for foundries and the like providing fluid pressure operated stop means for positioning and supporting sand containers.

Yet another object is the provision of automated pneumatically operated foundry mold and core making machines of a simplified construction obtaining a high degree of reliability.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the varous ways in which the principles of the invention may be employed.

In said annexed drawings:

FIG. 1 is a front elevation partially broken away and in section of a core blowing machine in accordance with the present invention;

FIG. 2 is an end elevation of such machine partially broken away and in section as seen from the right in FIG. 1;

FIG. 3 is an enlarged fragmentary detail view partially broken away and in section of the pneumatic intermediate stop mechanism;

FIG. 4 is a schematic pneumatic operational diagram of the machine illustrated in FIGS. 1 through 3;

FIG. 5 is a fragmentary vertical section of a foundry molding machine illustrating the employment of a similar pneumatic stop mechanism; and

FIG. 6 is a schematic pneumatic operational diagram illustrating the operation of the stop mechanism shown in FIG. 5.

Core blowing machine Referring first to FIGS. 1 and 2, there is illustrated a core blowing machine constructed in accordance with the present invention which comprises a base frame 1 on which are supported four columns 2, 3, 4 and 5 at each corner of the machine. The base frame 1 includes a depending cylinder 6 housing a large clamp piston 7, the reduced diameter tubular rod 8 of which supports table 9 for vertical movement.

Mounted on the columns 2 through 5 is a head 12 which is secured to such columns and to the base frame 1 by means of elongated tensioning members 13 illustrated in FIG. 1. The top frame or head 12 includes a vertically extending passage 15 seen in FIG. 2 which branches and is connected to blow valve 16 and exhaust valve 17 mounted on the top of the machine. The lower end of the passage 15 extends through blow head frame 18 which is provided with a peripheral seal indicated at 19. Each of the posts 2 through 5 is provided with brackets 21 on the inner sides thereof supporting horizontally extending

parallel rails

22 and 23. Such rails support tandemly arranged reservoir and

manifold carriages

25 and 26 which are interconnected by links 27. The carriages are supported on the rails by means of rollers 28 having V-shaped grooves therein which are mounted in carriage wheel brackets 29. Such brackets and supporting rollers are mounted at the corners of each carriage and support the same for horizontal shuttling movement along the

rails

22 and 23. The reservoir carriage 25 supports cylindrical sand reservoir 30 having frusto-conical bottom portion 31 terminating in blow plate 32 which may be provided with a series of blow openings 33 through which the sand within the reservoir is discharged. As indicated at 35, the wall of the cylindrical and frusto-conical portions of the reservoir may 'be jacketed so that a cooling fluid such as water may be circulated about the reservoir to maintain the sand-resin mix therewithin at the proper temperature to prevent premature cure. Covers 36 to access ports in the frusto-conical portion 31 may be provided for cleaning the interior of the reservoir. The interior cylindrical portion 37 of the reservoir extends upwardly through the carriage 25 and may be brought into registry with the ring 18 and seal 19' communicating with the passage 15. Normally, the top of the carriage is provided with. adequate clearance to shuttle to and from a position in registry with the blow opening in the head 12.

Such shuttling movement is obtained by a pair of piston-cylinder assemblies 40 which may be mounted on trunnion blocks 41 on brackets 42 at the left side of the head 12 seen in FIG. 1 and the rods 43 thereof are connected at 44 to bracket plates 45 secured to the reservoir carriage 25. In this manner, the shuttling movement of the reservoir carriage and through the link 27, the manifold carriage 26, is obtained. When the pistoncylinder assemblies 40 are retracted, the upwardly open cylindrical interior 37 of the reservoir will be positioned beneath hopper 47 which may be connected to a sand supply, not shown. The hopper 47 includes a chop gate 48 which is pivoted at its top to shaft 49 which has secured thereto link 50 connected at 51 to the rod of piston-cylinder assembly 52. The assembly 52 is mounted on a trunnion block 53 mounted on the end of the head frame 12 shown broken away in FIG. 1. It can now be seen that extension of the assembly 52 will cause the chop gate 48 to pivot about the shaft 49 to open and close the hopper to drop or dispense the resin-sand mix therewithin into the reservoir 30 when positioned vertically in registry therewith.

Such registered position will be obtained when the piston-cylinder assemblies 40 retract the reservoir 30 to the fill position beneath the hopper 47. In such position, the manifold carriage 26 will then be positioned directly vertically above the table 9. The manifold carriage 26 includes vertically extending side plates 54 and 55 which support a bottom plate 56 on which is mounted a vertically extending pneumatic cylinder 57, the rod of which is connected to manifold adapter plate 58 and guide rods 59 mounted in bushings 60 assist in the alignment and guiding of the plate 58 for vertical movement. An adapter frame 61 is secured to the bottom of the adapter plate. To the frame 61 will be attached a heating and punch out mechanism which may include a gas manifold for the cope portion of the mold box as well as vertically extending plates or pins adapted to clean the apertures in the top of the cope and facilitate the stripping of the blown core from the cope. The configuration of the heating and punch out mechanism, which is mounted for vertical movement on the manifold carriage 26 by means of the vertically extending piston-cylinder assembly 57, will vary according to the customers requirements and, of course, according to the particular sand cores being formed. In any event, it is apparent that as the reservoir 30 is moved from the blow poistion illustrated in FIG. 1 to the fill position beneath the hopper 47, the heating and punch out head carried by the manifold carriage 26 will then be positioned vertically above the table 9. An illustrative form of the manifold and punch out pins are shown in phantom lines at 62 in FIG. 1.

The cope portion C of the mold box is also shown in phantom lines and is normally supported on brackets 63 secured to the posts 2 through 5. Such brackets may include locating pins 64 seen in FIG. 2 on which the cope is precisely positioned and supported. The lower half of the mold box or drag D may be supporteddirectly on the table 9.

In operation, the table 9 will be elevated to cause the drag D to engage the cope C to lift the latter from the locating pins 64 to form the core or mold enclosure and then the enclosure is further elevated to clamp the same against the blow plate 32, which when the reservoir is in the position shown in FIG. 1, will be aligned with the blow ring 18. The vertical movement of the table may actually lift the reservoir and its carriage from the

rails

22 and 23 to clamp the reservoir against the seal ring 19. The mold enclosure comprised of the cope and drag and the reservoir will then firmly be clamped together. After the sand is then blown within the core box thus formed, the reservoir must be unclamped to permit the same to be shifted laterally to a fill position beneath the hopper and the manifold carriage 26 to be positioned thereabove. In order to accomplish this, the table 9 must be lowered to an intermediate or cure position but not far enough to cause the cope to engage the supporting pins 64 and thus start to separate the mold halves. It is, of course, extremely difficult to position precisely the table 9 by means of the large pneumatic piston 7. To accomplish this precise intermediate positioning of the table, there is employed a stop ring 65 surrounding the piston rod 8 within the top of the cylinder 6.

Referring now more particularly to FIG. 3, it will be seen that the cylinder 6 is provided with a top flange 66 seated on annular support 67 in the base frame 1. The flange 66 supports annular cap 68, the top of which surrounds annular guide 69 for the clamp piston rod 8. The interior of the cap 68 is provided with a cylindrical guide surface 70 sl'idingly confining the annular top 71 of stop ring 65. The stop ring 65 includes a downwardly extending cylindrical portion 72 having an annular shoe 73 forming an abutment to engage the top surface 74 of the clamp piston 7. A stop ring 75 is secured to the lower end of the cap 68 within the cylinder wall 6 and the inwardly projecting shoulder formed by the ring 75 serves to engage the top or piston portion 71 of the ring :65 limiting vertical movement thereof. Such piston portion 71 is provided with a piston ring 76 and the upper outer edge thereof is recessed as indicated at 77 and such recess is in communication with tapped air passage 78 in the wall of cap 68. A vent passage 79 is provided in the cap 68 and may serve to vent both the upper end of the clamp piston 7 as well as the lower end of the piston portion 71 of the stop ring 65.

It can now be seen that the clamp piston 7 can be driven down to the intermediate position simply by pressurizing the air passage 78 at high pressure causing the abutment or shoe 73 of the ring 75 to engage the top surface 74 of the clamp piston 7 to drive the same downwardly. Air under low pressure beneath the clamp piston will maintain the

surfaces

73 and 74 together with the piston portion 71 in engagement with the ring 75.

Further describing the core blowing machine embodiment of the present invention, it will be seen in FIG. 1 that the table 9 includes a vertically extending guide rod 80 extending through bushing 81 to keep the table 9 from rotating Within the cylinder 6 and to maintain the cope and drag of the mold box in precise vertical alignment.

After the intermediate position is achieved and the cores have been cured sufficiently to strip from the mold box, the air pressure beneath the clamp piston 7 is vented and the table 9 descends to deposit the cope C on the supporting brackets and the stripping pins within the heating and punch out head shown in phantom lines at 62 may assist in cleaning the apertures in the cope and stripping the core therefrom, The cores now within the drag D or bottom half of the mold box will then descend and stripping pins may then be employed to cause the cores and drag to separate. The pins may be mounted for vertical movement with respect to the drag by piston-cylinder assemblies or the pins may be caused to engage fixed abutments so that the drag will be lowered therepast to cause the cores to be elevated above the top of the drag. The drag too may be provided with a heating manifold and in order to remove the cores from the machine, a plurality of pickoif fingers 84 may be employed to move beneath the cores and withdraw the same from the machine. Such pick-off fingers are mounted on a head frame 85 pivoted at 86 to vertically extending pivot bracket 87 mounted on carriage 88. The carriage 88 may be provided with top and bottom rollers 89 at each end thereof which confine therebetween rail 90. A link 91 is pivoted at 92 to the carriage and at its opposite end to one arm of bell crank 93. The opposite end of the bell crank is pivoted at 94 to the frame and the crank 93 may be pivoted about the pivot 94 by means of the pistoncylinder assembly '96 which is mounted on trunnion block 97. The rod 98 of the assembly 96 is pivoted at 99 to the crank 93. Accordingly, when the assembly 96 is retracted, the carriage 88 is caused to move along the rail 90 to advance the fingers 84 into the machine beneath the cores. Conversely, when the assembly 96 is extended, the carriage 88 is caused to move along the rail 90 to retract the fingers 84 from the macine.

The fingers 84 may be raised and lowered by means of a piston-cylinder assembly 100 mounted on the carciage 88, the rod of which is connected at 101 to link 102. The proximal end of the link 102 is pivoted at 103 to the carriage 88 and directly therebeneath is a parallel link 104 pivoted at 105 to the carriage and at 106 to the bottom of the vertically extending portion 87 of the bracket supporting the finger frame 85. The vertically extending portion 87 is also pivoted at 107 to the link 102 so that the

pivots

103, 105, 107 and 106 form a parallel linkage to raise and lower the fingers 84 at the direction of the piston-cylinder assembly 100, all of the linkages as well as the assembly 100 being mounted on the carriage 88 for movement with the fingers into and out of the machine.

In addition, the fingers 84 may be tilted about the horizontal axis of the pivot 86 by means or piston-cylinder assembly 110 seen more clearly in FIG. 1, the rod of which is pivoted at 111 to the frame 85 and the cylinder may be mounted on bracket 112 connected to the carriage. In this manner, an operator standing to the side of the finger mechanism may receive the blown cores withdrawn from the machine more conveniently. The various linkages on the carriage may be mounted in a protective housing 113 supported on frame members 114 extending from the horizontal support frame 95 extending laterally from the machine.

Core blowing machine-opemti0n-FIG. 4

Referring now to FIG. 4, the operation of the core blowing machine embodiment of the present invention may be electric and pneumatic and operated through a complete cycle in a completely automatic manner. Air may be supplied from a plant source to a filter and a line lubricator 121 from which air passes through a manually operated lock-out valve 122 to valve inlet manifold 123. A branch line 125 between the lubricator and filter leads to a pressure regulating valve 126 leading to air storage tank 127. The storage tank 127 is connected to the blow valve 16 which is in turn connected to the reservoir 30 when the carriage 25 is in position beneath the blow head. The air storage tank 127 is also connected to the exhaust valve 17 through a two-way poppet valve 128 which is in turn controlled by a mechanically operated reservoir safety valve 129.

Parallel to the inlet header 123 is an exhaust header 131 and connected to the parallel headers are the function control valves. The top valve 132 is a single solenoid valve which may be employed to cause the table to elevate upon the energization of the associated solenoid. Air is supplied from the inlet header 123 to the line 133 to poppet valve 134 which is then shifted to open line 135 which may be connected at 136 to the air supply for providing filtered and lubricated air to the various poppet valves. The wall of the cylinder 6 may be provided with two inlets, one slightly above the other and the upper may be slightly larger as compared to the lower. For example, the upper may be a 2-inch inlet, while the lower is a /2-inch inlet. A flow control valve 136 is connected to the lower inlet and a pressure gauge 137 as well as pressure switches 138 and 139 are also provided connected to the lower inlet.

The pressure switch 138 may be employed to indicate the full clamp pressure being obtained so that the blow operation may commence. The pressure switch 139 is preset for a specified range and may be employed to control solenoid valve 140 supplying air through line 141 to twoway poppet valve 142 so that air supplied through line 144 from source 136 through three-way poppet valve 145 will force the stop ring 65 downwardly pushing the piston 7 downwardly to the intermediate or cure position. The three-way poppet valve 145 is controlled by solenoid valve 147 supplying air through line 148 to the poppet. In this manner, the table 9 is held at an intermediate cure position while still supported on a relatively large volume of air. The cure position must be precisely maintained especially if additional heating equipment such as arbors are employed which project laterally into openings within the core box.

The clamp pressure switch 138 signals the blow control valve 150 supplying air through line 151 and venting line 152 opening the blow valve 16 while closing the exhaust valve 17. The

carriage

25, 26 is controlled through double solenoid valve 153 operating three-way poppet valves 154 and 155 to supply air selectively to the rod and blind ends of the carriage cylinder assemblies 40 through the flow control valves illustrated. The chop gate 48 may be operated directly from the double solenoid valve 156 which causes the piston-cylinder assembly 52 to extend and retract, The cope strip cylinder assembly 57 on the carriage 26 is actuated by double solenoid control valve 158 which actuates

poppets

159 and 160 retracting and extending, respectively, the assembly 57. Double solenoid control valve 161 is employed directly to actuate the cylinder assembly 110 tilting and untilting the core fingers 84 while the double solenoid valve 162 is employed directly to operate the assembly 100 to raise and lower the fingers. The double solenoid valve 163 is employed to advance and retract the fingers 84 by actuating the poppet valves 164 and 165, respectively, supplying air to the rod and blind ends of the assembly 96 through the flow control valves illustrated.

An automatic cycle of the machine would start with the table or clamp cylinder in its lowermost position and with the fingers 84 retracted. The carriage with a reservoir charged with sand would be extended so that the reservoir is in the blow position shown in FIG. 1. With the machine in such condition, the table 9 is then elevated by the valve 132 and at the same time the retracted fingers 84 may be tilted by the cylinder assembly 110 so that the operator may remove the previously blown cores from the machine. The piston 7 continues upwardly to assemble the drag portion D with the cope portion C of the mold box lifting the latter from the support and aligning pins on the frame to move the now assembled mold box against the blow plate 32 of the reservoir 30. During such movement, the piston 7 will elevate the stop ring assembly 65 with the poppet valve 145 positioned to exhaust air from the cylinder wall 70 through port 78. Continued upward movement of the clamp piston will engage the reservoir and the mold box lifting the former from the rails 22. and 23 seating the same against the blow head. The pressure switch 138 will then actuate the blow valve 150 to blow the sand from the reservoir into the mold box. The

valves

140 and 147 are then actuated and with the aid of the pressure switch 139 the stop ring 65 will engage the top of the piston 7 to lower the table to the intermediate cure position. A limit switch signalling that the table has achieved the intermediate cure position will then start the time cure cycle and also energize the valve 153 to retract the assemblies 40 moving the

carriages

25 and 26 to the fill position. In such position, the carriage 26 will move the cope cure and punch-out head above the now lowered mold box. When the carriage is at the fill position, a limit switch will open the chop gate 48 through the valve 156 and may also prepare the cope strip piston-cylinder assembly 57 to be actuated through the valve 158. When the cure cycle is complete, the chop gate 48 will be closed and the piston-cylinder assembly 110 may again be actuated to bring the fingers 84 to a horizontal position. The table 9 is now lowered to separate the cope from the drag and the cores will remain in the drag as the table is lowered. Stripping fingers either fixed or vertically movable may then elevate the cores above the drag and when the table is in its lowermost position, being cushioned by the flow control valve 136, the fingers 84 are then advanced by retraction of the piston-cylinder assembly 96 at the direction of the valve 163, At the same time, the cope strip assembly 57 may be retracted and the carriage indexed to its blow position with the reservoir vertically above the table. The valve 162 is then actuated to elevate the fingers 84 to raise the same from the stripping pins and the valve 163 may then cause the piston-cylinder assembly 96 to extend retracting the fingers 84 and thus the cores from the machine.

Molding machine Referring now to FIGS. and 6 and first to FIG. 5, there is illustrated the base section of a foundry molding machine which includes a base frame 170 provided with four upstanding posts 171 at the corners thereof which may supoprt a sand hopper, measuring box, and a shuttling carriage including a squeeze head and a sand chute. Reference may be had to the copending application of Leon F. Miller et al., Serial No. 252,644, filed January 21, 1963, entitled Molding Machine, now Patent No. 3,205,542, for an illustration of a similar but hydraulic type of foundry molding machine utilizing foundry flasks which are trundled to and from the machine for the jolting and ramming of foundry sand therewithin.

The base frame 170 supports therewithin a large cylinder 172 which includes top and bottom rings 173 and 174 and a bottom membr 175 closes the lower end of the cylinder. The bottom closure 175 may be provided with an air inlet as indicated at 176. The top of the cylinder 172 is provided with a cap 177 which may be secured to the top of the cylinder by suitable fasteners 178. Soft copper or like material gaskets may be provided at 180 and 181 to provide a sealed cylindrical enclosure for the main squeeze piston 183. Projecting upwardly from the main piston 183 is a cylinder 184 which may be secured to the piston by the fasteners indicated at 185. A peripheral top flange 186 is mounted on the top of the cylinder 184 and may be secured thereto by the fasteners 187. Reciprocably mounted within the cylinder 184 is a shockless ram piston 190 supported on heavy duty coil spring 191. The ram piston 190 includes an upstanding cylindrical portion 192 which receives therein the depending jolt piston 193 secured to the table 194 which in turn supports pattern stool 195 on which the pattern plate and pattern will be positioned,

The cylinder 184 then constitutes a hollow piston rod for the squeeze piston 183 while the cylindrical portion 192 of the shockless ram piston 190 constitutes the cylinder for the jolt piston 193 on which the table is mounted,

For a more clear disclosure of a similar shockless jolt mechanism, reference may be had to the copending application of Robert W. Ellms, entitled Molding Machine, Ser. No. 322,405, filed Nov. 8, 1963.

Air for the jolting operation is supplied through line 197, vertically extending passage 198 in the jolt piston 193, by-pass porting passage 199 in the cylindrical portion 192 of the ram piston 190, and finally vertically extending passage 200 in the jolt piston 193. When air is supplied through such passages to the chamber 202 between the ram and jolt

pistons

190 and 193, the latter will be caused to elevate and the former will be driven downwardly against the spring 191. Such movement will continue until the exhaust passage 203 is opened at which time the by-pass passage 199 will block communication between the

passages

198 and 200. The exhaust passage 203 communicates with vertically extending passage 204 in the ram piston 190. Such vertical passage is in communication with the chamber 205 beneath the ram piston 190 and the jolt exhaust air passes out through the top port 206. The exhaust escape passage 204 may be restricted to cause an increase in the pressure in chamber 205 beneath the ram piston 190 and this pressure may 8 assist the spring 191 in driving the ram piston upwardly. Simultaneously, due to the jolt air being exhausted, the jolt piston 193 starts to descend gravitationally and the two meet at 207 causing the jolt action.

However, prior to such jolt action, the table 194 must be elevated to pick up a flask so that the same will enclose the pattern supported on the stool 195, such flask usually being conveyed into the machine on a roller conveyor. The thus elevated flask and the pattern therewithin form the mold box and sand must then be placed therein. To do this, the main squeeze piston 183 must be elevated to assemble the flask and pattern and support the former above the roller conveyor for the filling and jolting operation. If the machine utilizes a horizontally shuttling squeeze head, such must be shuttled into position above the flask while the latter is supported in its intermediate position and further elevation of the squeeze piston 183 will then ram the sand within the flask against the squeeze head.

In order to obtain the precise intermediate positioning required in the pneumatic molding machine illustrated, a stop ring 210 is employed which is similar in purpose and configuration to the stop ring 65 in the FIG. 3 core blowing machine embodiment. The stop ring 210 includes a cylindrical rod portion 211 and a piston portion 212 at the bottom thereof provided with a sliding seal 213 in engagement with the interior of the main cylinder 172. The cylindrical rod portion 211 of the ring 210 is fitted between the exterior of the cylindrical rod 184 of the squeeze piston 183 and ring 215 mounted on shoulder 216 on the interior of the cap 177. A chevron type gland 217 may be provided, the top of which is confined by L-shape ring 218 secured by fasteners 219 to the top of the cap 177. The upper portion of the cylindrical rod 211 is provided with a ring 220 which serves as an abutment limiting vertical movement of the stop ring 210. A shelf 221 is provided on the ring abutment 220 and

flexible boots

222 and 223 extend above and below the shelf, respectively, to protect the sliding parts of the machine from dust and dirt. An air inlet 225 is provided in the cap 177 communicating with the chamber 226 above the stop ring piston 212 and a vent passage 227 on the interior of the cylindrical rod portion 211 of the stop ring 210 is provided for the annular chamber 228 formed by the

cylinders

184 and 172 between the

pistons

212 and 183.

Molding machineoperati0n Referring now to FIG. 6, it will be seen that air may be supplied from a suitable source 230 through a manually operable lock-out valve 231 to air line 232 from which

branches

233, 234, 235 and 236 extend. The latter is connected to a plug-in type single solenoid pilot operated four-way valve 237 which includes a solenoid operated valve 238, a manual override valve 239, and two positional directional valve 240 operated thereby to supply air selectively to the line 197 connected to the table 194 to provide the jolt action.

The line 235 is provided with a filter 242, an air pressure regulator 243, and a line lubricator 244.. From the lubricator, the air passes to plug-in type double solenoid pilot operated four-

Way valves

245 and 246, each of which may include solenoid valves 247 and 248 and

manual override valves

249 and 250, respectively, pilot operating two-position directional valve 251. The valve 245 operates

poppets

252 and 253 in

lines

233 and 234,

respectively, and the valve 246 operates

poppets

254 and 255 in line 234 and exhaust line 256, respectively.

Air may also be supplied from source 258 through lock-out valve 259 to line 260. Such line may be provided with a pilot regulator 261 and a pilot operated pressure regulator 262 as well as a check valve leading to an air receiver 264 for air at about 40 p.s.i., for example. The receiver 264 is connected to the poppet 253 and thus selectively connectible to the line 234 beyond such poppet. The line 234 passing through the

poppets

253 and 254 is 9 connected to the main cylinder 172 through the illustrated

ports

266 and 267, the lower being the smaller of the two and may be connected to the passage 172 illustrated in FIG. 5. Pressure switches 268 and 269 are connected to the

lines

233 and 234, respectively, sensing the respective pressures above the stop ring piston 212 and beneath the squeeze piston 183. The

poppets

252, 254 and 255 are each provided with exhaust mufliers as seen at 270.

The cycle of operation will, of course, start with the table in the lowermost position and when in such position, the flask will be trundled above the pattern supported on the plate upon the stool 195. Now to elevate the table, the valve 246 may be actuated to close the

ex haust poppets

254 and 255 so that air will enter beneath the squeeze piston 183 through the line 260 and the 40 psi. air receiver 264. With the poppet 252 in the position shown, air will be supplied to the top of the stop ring piston 212 through the line 233 which may be connected to the source 230 which may be at regular plant line pressure at approximately 100 p.s.i. The higher pressure behind the piston 212 will thus provide a positive stop for the squeeze piston 183 as it moves upwardly to elevate the flask from the conveyor rolls or like equipment. In such intermediate position, sand will then be placed within the flask, struck off, optionally jolted, and a squeeze head may then be positioned vertically above the flask. At the completion of the jolting operation and when the squeeze head is properly positioned, the valve 245 may then be employed to reverse the

poppets

252 and 253 now venting the chamber above the stop ring piston 212 and supplying regular high pressure plant air to the bottom of the squeeze piston 183. Pressure may continue to be built up to the desired degree regulated by the switch 269 at which time the valve 246 may be reversed venting the main squeeze piston. The pressure switch 268 may be employed to signal the required stopping pressure behind the stop ring piston 212 permitting the elevating of the table and thus the cycle of operation to commence. It will, of course, be appreciated that the jolting action can be employed simultaneously with the further elevation of the table during the squeeze operation. But in any event, the table requires to be positioned precisely in an intermediate position for the flask filling and squeeze head shuttling operation.

As the table descends, the flask with the formed mold therein will be deposited on the conveyor mechanism for trundling from the machine and the pattern Will be stripped therefrom upon further lowering of the table.

It can now be seen that there is provided pneumatic sand forming foundry machines whereby an intermediate position of the table or support is precisely conveniently obtained 'by differential forces acting upon the main clamp or squeeze piston and the stop ring. In the illustrated embodiments, the differential forces are obtained by differential pressures and such forces are, of course, dependent on the areas over which such pressures are applied. Because of the much larger area of the clamp or squeeze piston, only a relatively slight increase in pressure is required to overcome the force exerted by the smaller stop ring to elevate the table or support there beyond. Pressure variations can be obtained in many ways and those illustrated are considered simply to be examples which might conveniently be employed with the two types of machines illustrated.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

I, therefore, particularly point out and distinctly claim as my invention:

1. A core blowing machine comprising a vertically movable table adapted to support a drag portion of a mold box, a piston rod extending from said table having a main clamp piston thereon, a cylinder surrounding said main clamp piston, means to supply air under pressure directed single acting pistons, and means to vary the pressures acting thereon to achieve such intermediate position.

3. A core blowing machine as set forth in claim 2 including a common exhaust passage for said pistons.

4. A core blowing machine comprising a vertically movable table adapted to support a drag portion of a mold box, a piston rod extending from said table having a main clamp piston thereon, a cylinder surrounding said main clamp piston, means to supply air under pressure beneath said piston to elevate said table to assemble such drag portion with a cope portion and clamp the thus formed core box against a sand reservoir, a stop piston surrounding said rod above said main piston, means limiting vertical movement of said stop piston, means operative to energize said stop piston to drive said main piston downwardly to a predetermined intermediate position, said main and stop pistons comprising oppositely directed single acting pistons, means to vary the pressures acting thereon to achieve such intermediate position, a common ex-haust passage for said pistons, a depending annular shoe on said stop piston operative to engage said main piston, and a shoulder ring limiting vertical movement of said stop piston but clearing said annular shoe.

5. A core blowing machine comprising a vertically movable table adapted to support a drag portion of a mold box, a piston rod extending from said table having a main clamp piston thereon, a cylinder surrounding said main clamp piston, means to supply air under pressure beneath said piston to elevate said table to assemble such drag portion with a cope portion and clamp the thus formed core box against a sand blow reservoir, a stop piston surrounding said rod above said main piston, means limiting vertical movement of said stop piston, means operative to energize said stop piston to drive said main piston downwardly, said stop piston including a depending shoe operative to engage said main piston, and means to hold said main piston against said shoe in such intermediate position.

6. In a foundry sand forming machine, a large diameter main elevating piston and rod adapted to support a sand enclosure, a stop piston surrounding said rod and operative to engage said main piston, and means operative to pressurize or vent said stop piston thus differentially to pressurize said pistons to hold said main piston in an intermediate position.

7. A foundry sand forming machine as set forth in claim 6 wherein said last mentioned means includes means to increase the pressure on said stop piston with respect to said main piston to push the latter downwardly to such intermediate position.

8. A foundry sand forming machine as set forth in claim 6 including means to increase the pressure on said main piston with respect to said stop piston to push the latter upwardly from such intermediate position.

9. In a foundry sand forming machine, a main elevating piston adapted to support a sand enclosure on the rod thereof, a stop piston surrounding said rod above said main piston and operative to engage the latter, and means operative to pressurize said stop piston to provide a force greater than that on said main piston to hold the same in an intermediate position.

10. A foundry sand forming machine as set forth in claim 9 wherein such intermediate position is achieved by moving said main piston upwardly.

11. A foundry sand forming machine as set forth in 1 1 claim wherein such intermediate position is achieved by moving said stop piston downwardly.

12. In a foundry sand forming machine, a main piston and rod adapted to support a sand enclosure, a stop piston surrounding said rod adapted to engage said main piston, and means limiting the stroke of said stop piston to pro vide a releasable abutment for said main piston, said main and stop pistons comprising oppositely directed single acting pistons.

13. A foundry sand forming machine as set forth in claim 12 including a common vent between said pistons.

14. In a foundry sand forming machine, a large cylinder, a main elevating piston adapted to be supported on a large volume of air within said cylinder, a rod extending from said piston and adapted to support a foundry sand forming pattern for vertical movement, a stop ring surrounding said rod above said piston and adapted to be engaged thereby, means limiting vertical downward movement of said stop ring, means operative to hold said stop ring in such limited lower position to provide an abutment for said main piston, and means operative to release said stop ring whereby said main piston may continue upwardly.

15. A foundry molding machine comprising a vertically movable table adapted to support a pattern, a piston rod supporting said table, a main squeeze piston thereon, a cylinder surrounding said main squeeze piston, means to supply air under pressure beneath said squeeze piston to elevate said table to assemble such pattern with a flask, a stop piston surrounding said rod, means limiting vertical downward movement of said stop piston, means to supply air under pressure to said stop piston holding the same down to engage said main squeeze piston and thus hold such pattern and flask in an intermediate position to be filled with sand, and means to change the pressures on said main and stop pistons to move such sand filled flask upwardly from such inter-mediate position to squeeze the sand therein.

16. A foundry molding machine as set forth in claim 15 wherein said main and stop pistons are oppositely directed single acting pistons.

17. A foundry molding machine as set forth in claim 16 including a common intermediate vent for said pistons.

18. A foundry molding machine comprising a vertically movable table adapted to support a pattern, a piston rod supporting said table, a main squeeze piston thereon, a cylinder surrounding said main squeeze piston, means to supply air under pressure beneath said squeeze piston to elevate said table to assemble such pattern with a flask, a stop piston surrounding said rod, means limiting vertical downward movement of said stop piston, means to supply air under pressure to said stop piston holding the same down to engage said main squeeze piston and thus holdsuch pattern and flask in an intermediate position to be filled 'Wllll sand, means to change the pressures on said main and stop pistons to move such sand filled flask upwardly from such intermediate position to squeeze the sand therein, said rod being hollow and containing a shockless jolt mechanism vertically movable with said table.

19. A foundry sand forming machine as set forth in claim 14 including means operative to pressurize said stop ring to drive said main elevating piston downwardly to an intermediate position.

References Cited UNITED STATES PATENTS 787,480 4/ 1905 Tanner 92--62 2,118,098 5/1938 Merenda 9262 X 2,122,022 6/1938 Campbell 22-26 X 2,611,938 9/1952 Hansberg 22,l0

J. SPENCER OVERHOLSER, Primary Examiner.

E. MAR, Assistant Ex'aminer.