US2901791A

US2901791A - Foundry core making machines

Info

Publication number: US2901791A
Application number: US716499A
Authority: US
Inventors: Beech Austin Sidney
Original assignee: Foundry Equipment Ltd
Current assignee: Foundry Equipment Ltd
Priority date: 1956-10-29
Filing date: 1958-02-20
Publication date: 1959-09-01
Anticipated expiration: 1976-09-01

Description

Sept. 1, 1959 A, s, BEECH 2,901,791

FOUNDRY CORE MAKING MACHINES Filed Feb. 20, 1958 ll Sheets-Sheet 1 7 Sept. 1, 1959 A, s, BEECH 2,901,791

FOUNDRY CORE MAKING MACHINES Fileg Feb. 20, 1958 11 Sheets-Sheet 2 I /Z.9' 3/ F/G. Z.

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u I q I 4a in" I n |l u III l||l a /9 l o 0 d Sephl, 1959 A. s. BEECH FOUNDRY CORE MAKING MACHINES ll Sheets-Sheet 3 Filed Feb. 20. 1958 Sept. 1, 1959 A. s. BEECH FOUNDRY com: MAKING MACHINES ll Sheets-Sheet 4 Filed Feb. 20, 1958 p 1,1959 A. s. BEECH 2,901,791

FOUNDRY CORE MAKING MACHINES Filed Feb. 20, 1958 V 11 Sheets-Sheet 5 a Haj #7 #7 6 A 1 #0 A f /b0 5 #6 o o O 7/5 h #5 f O O 0 V w #2 /4/ -43; w I w /J5 M3 M b '56 g /7 P 1, 1959 A. s. BEECH 2,901,791

FOUNDRY CORE MAKING MACHINES Filed Feb. 20, 1958 ll Sheets-Sheet 6 Sept, 1, 1959 A. s. BEECH FOUNDRY CORE MAKING MACHINES ll Sheets-Sheet 7 Filed Feb. 20, 1958 Sept. 1, 1959 A. s. BEECH 2,901,791

FOUNDRY CORE MAKING MACHiNES Filed Feb. 20, 1958 -ll Sheets-Sheet 8 Sept. 1, 1959 A. s. BEECH FOUNDRY CORE MAKING MACHINES 11 Sheets-Sheet 10 Filed Feb. 20, 1958 Sept. 1, 1959 A. s. BEECH 2,901,791

, FOUNDRY CORE MAKING MACHINES Filed Feb. 20, 1958 ll Sheets-Sheet 11 f/za w a? F/G/J" United States Patent 2,901,791 FOUNDRY CORE MAKING MACHINES Austin Sidney Beech, Leighton Buzzard, England, assignor to Foundry Equipment Limited, Leighton Buzzard, England, a British company Application February 20, 1958, Serial No. 716,499 6 Claims. (Cl. 22-40) This invention relates to foundry core making machines. p It isan object automatic or semi-automatic machine for filling coreboxesby blowing sand-mix into them with the aid of compressed air, and for thereafter removing the moulded cores from the boxes. The invention comprises, in foundryicore-blowingmachinesthe combination of a sand box at a filling, station for holding a charge of sand mix, a travelling and invertible core-box support for carrying a core-box to and from the sand box forfilling, means for supplying compressed air to the sand box to blow sand therefrom into the core box, means for inverting the core-box support when carried awayfrom the sand box to a removing station and means for removing the core from the core-box atthe removing station.

According to a feature of the invention, the core-box support comprises a one-piece casting with an open topped internal cavity to receive a divided core-box, piston-andcylinder unitsclamped to the walls of the casting for opening and closing the core-box, and trunnions on opposite ends of the casting whereon it is mounted for inversion. According to another feature, the core-box support is mounted on a carriage on trunnions, for inversion, the carriage is mounted on rails to enable it to travel between the blowing and removing stations and a pistonand cylinder mechanism is mounted on the carriage and operatively connected to the core-box support to effect inversion thereof. The piston-and-cylinder mechanism may be operatively connected to the core-box support by a rack actuated by the piston and a pinionon the corebox support.

Preferably, the carriage is formed as an open rectangular frame, the cylinder is formed as an integral part of the frame across one end thereof, the piston is a long element in the cylinder and carries the rack between its two ends and the runnion bearings are formed in the frame with their axis above the rack and the pinion on one trunnion extending through an aperture in the upper side' of the cylinder so as to mesh with the rack.

According to another feature, the sand box is mounted on a carriage to travel to and fro beneath an air blowi'ng head and a sand-mix delivery chute, and a sliding shut-off valve plate is interposed between the sand box and the blowing head and delivery chute, and is divided into an aperture'd portion, which comes alternatively below the blowing head and the delivery chute, and a solid portion to close off the lower end of the delivery chute when the sand box is below the blowing head, the two portions being arranged to slide horizontally as one.

According to a further feature, an air-operated diaphragm valve controls the admission of air under pres,- sure to the blowing head for blowing the cores, a spring is provided to load the .valve toward the closed position, the spring pressure being adjustable to obtain a rapid valve action.

of the invention to provide-an improved f'ice The above and other features of the invention will be apparent from the following description given by way of example, of a core blowing machine according to the invention which is intended primarily for the production of mould cores to be used in casting cylinder blocks for internal combustion engines. It will be convenient first to describe the general layout and method of operation of the machine.

In the drawings,

Figure l is a general perspective view of the machine;

Figure 2 is a perspective View on a larger scale of one end of the machine viewed from the opposite side of that shown in Figure 1 and with certain parts broken away;

Figure 3 is a section of a roll-over cylinder;

Figure 4 is a section upon the line 4-4 of Figure 3, looking in the direction of the arrows;

Figure 5 is a detail partly in section of a draw-cylinder assembly;

Figure 6 is a plan of a cast core-box support;

Figure 7 is a side elevation of a portion of the centre of the machine;

Figure 8 is an elevation in a plane at right angles to Figure 7;

Figure 9 is a part-sectional elevation of blowing and ramming mechanism;

Figure 10 is an outline plan of the core-box support and its carriage;

Figure 11 is a detail of the rail mounting for the carriage;

Figure 12 is a section of the cylinder for lifting the carriage toward the blowing apparatus and Figures 13 and 14 are details of swing-out mechanism.

The machine has a massive fixed framework compris ing a central tower 11 and two oppositely-extending

wings

12, 13 on either side of the tower. Extending from wing to wing and through the tower are a pair of stout horizontal track rails 14, 15 (see Figures 7 and 8) and on these rails are mounted two core-

box assemblies

16, 17 each of which runs on its own carriage from one of the

wings

12 or 13 as the case may be, to a central position in the tower 11 and back again. The two corebox assemblies move in turn into the central position in the tower; that is to say while one is travelling in and out along the rails the other remains at the outermost limit of its travel. In Figure l the machine is doubled; that is, there is a second tower 21 with

wings

22, 23 and carriages 26, 27. A push-button control box 28 for the double machine is provided.

When either core-box assembly comes to rest in its central position in the tower, it is lifted up oil the

rails

14, 15 toward a sand blowing head in the upper part of the tower by a vertically-disposed pneumatic ram 18 in a cylinder 19 beneath it at the foot of the tower. The corebox assembly 16 (or 17) is raised until the open-topped core-box support holder 20 which it carries is clamped up into scaling contact against the underside of a sand box 30. Compressed air then blows sand-mix from the sand box down into the core-box held in the core-box support 20 for several seconds to fill the box and form the mould core. The sand box 30 forms part of a transfer assembly which is mounted to run on horizontal rails 32 extending from front to back of the tower, that is to say at right angles to the direction of travel of the core-box assemblies on their track, so that after each core has been blown the sand box assembly can travel from its position during blowing (shown in Figure 8) to a second station nearer the rear of the machine (in the case of. the nearer part of the machine as viewed in Figure 1) where its open upper end comes beneath a chute 33 (Figure 8) for delivering a fresh charge of sand-mix from a hopper (not shown) above the tower.

After the sand-mix has been blown into the core-box it is packed tight by the action of ramming pins on a squeeze pin assembly 34. The details of the said chamber, blowing arrangements and squeeze pin assembly are shown in Figure9. The squeeze pin assembly 34 runs on a further rail track 35 in the tower immediately below and parallel to the track 32 for the sand box assembly. During blowing of the core it lies at a station on its track in front of the core-box assembly and sand box, but after blowing, the core-box assembly 16 (Figure 8) is lowered away from the sand box 30 and the squeeze pin assembly 34 is run in to a station directly over the core-box so that a further raising of the core-box assembly causes squeeze pins 120 and squeeze plate 119 to perform a ramming action on the sand-mix in the core-box. I When the core has been blown and rammed, the corebox assembly 16 is lowered back to its position on the

track

14, 15 on which it runs, and it then travels out to its station at the extremity of one of the wings (12 or 13 as thecase may be) ofthe machine frame where the core-box support 20 is rolled right over through 180 (it is shown partly rolled over in Figure 2). A draw saddle 40 (Figure then rises from the bed of the machine frame to a position immediately beneath the inverted core-box assembly, and the core-box is opened within its support 20 to release the core and deposit it on a drier plate 41 placed on the draw saddle 40. Lowering of the draw saddle withdraws the core downwardly from the core-box, and finally when it is fully down an arm 42 (Figure 1) pivoted on the end of the machine frame about a vertical pivot 43, and carrying a horizontal fork 44, is swung in to insert the fork beneath the dried plate 41, the fork is raised slightly to lift the drier plate and core off the draw saddle, and the arm is swung out with the plate and core on the work. It can then be deposited on a conveyor to carry it to a baking o-ven. After the core-box support 20 has been rolled back into the upright position, and the core-box which it carries is closed, the assembly 16 is then ready to run back into the tower for the blowing of a further core. It will be appreciated that while the support on this core-box assembly has been rolling over and depositing its core on the core lift below for removal, the other core-box assembly 17 on the opposite wing or" the machine has run into the tower and passed through the core blowing operations in exactly the same way.

The various assemblies making up the machine will now be described in turn in some detail, commencing with the two core-box supports 16, 17 and their carriages, which are identical in operation. The carriage 16 for each core-box assembly (shown in Figure is provided with two pairs of supporting

wheels

44, 45 to run on the track rails 14, extending along the machine from wing to wing. The carriage is in the form of a massive one-piece casting which, when view in plan, takes substantially the form of a large rectangular frame; that is to say it has integral sides and ends surrounding a large central opening. The tops of the ends of the carriage are formed with central trunnion bearings 46, 47 which are aligned with one another on an axis central and parallel with respect to the track rails, and these trunnion bearings provide the mounting for the rollover core-box support 20.

The core-box support also has as its principal member a large one-piece casting, and this casting, while being a good deal deeper than the carriage casting, is smaller in plan, that is to say it is small enough to lie within the sides and ends of the carriage casting and to roll over in that situation without any part of it fouling the carriage.

tures into which are fitted short-stroke

pneumatic cylinders

53, 54 that project to some extent beyond the sides of the casting. These cylinders, which have their axes in alignment, contain pistons with rods 55, 56 (see Figure 6) projecting inwardly into the interior of the casting where they carry at their inner ends

large platens

57, 58 than can be moved toward and away from one auother by the piston-and-

cylinder units

53, 54 and are each additionally guided in this movement and held against rotation by a pair of diagonally-

opposedv guide rods

59, 60 in each case,'that pass into slide bearings 61, 62 on the side of the casting on opposite sides of the cylinder, Theopposite ends of the core-box assembly casting also have apertures to receive pneumatic-cylinders 63, 64, but in thiscase the cylinders are smaller and they carry in the interior of the casting comparatively narrow platens 65, 66 which move toward and away from one another between the aforesaid large platens57,

The four cylinders described on the core-box support casting serve the purpose of opening and closing the core-box, which is made in parts carried in the interior of the casting upon the four platens and is not shown in the drawing, as it will vary from job to job. The core-box would normally be divided both longitudinally and transversely, and the four parts so formed that when the platens move together under the control of their cylinders the core-box is closed, and when the platens move apart the core-box opens. Opening of the corebox takes place as previously mentioned when the core which it contains is to be released for withdrawal from the box. "It has been mentioned that the machine being described has been primarily designed to include the possibility of making mould cores for the casting of cylinder blocks for multicylinder automobile and like engines. Cores for this purpose normally have a portion (which is uppermost when the core is blown), corresponding to the cavity in the crank case section of the block, with a number of cylinder or barrel portions upstanding from the base and corresponding to the cylinder cavities. In the present machine if cylinder-block cores are to be blown, only that portion of the core-box which contains the base portion of the core is made in sections secured to the

platens

57, 58, 65, 66 which separate when the platens move out. The part of the core-box for shaping the cylinder barrel portions of the core is in a single piece, secured in the bottom of the cavity 48. The core after blowing is carefully withdrawn endwise from the barrel cavities in the core-box after the side sections of the core-box have been withdrawn by the

platens

57, 58, 65 and 66. To facilitate this withdrawal, a slight taper should be given to the cylinder cavities in the bottom section of the core-box.

The core-box support casting is substantially square in plan with a large square central cavity 48, and a pair of robust half-hoops 49, 50 are provided externally on its opposite end walls which carry trunnions 51, 52 that are received in the aforementioned trunnion bearings 46, 47 on the ends of the carriage. The opposite side walls of the core-box support casting have large diameter aper- When the core-box closes, the shorter sides of the box on the platens 65, 66 shut first and then the longer sides on

platens

57, 58, and dowels on the longer sides of the core-box engage the shorter sides and lock them in the closed position. The movements of the piston-andcylinder units 63, 64 operating the box are limited by internal stops in the cylinder, but since the longer sides of the box are kept closed by virtue of the pressure in their cylinders urging them against the shorter sides, there do not need to be any stops in the

large cylinders

53, 54. Locating of limit stops inside the cylinders 63', 64 keeps them protected from stray sand.

The core box is not shown in the drawings as it will vary in shape from job to job. In the case of work other than cores for cylinder castings the operation will be modified according to need and in some cases only two platens, such as 57, 58 will be in use, for a two-part core box.

All four

cylinders

53, 54 and 63, 64 have external flanges and are held in place on the sides of the corebox assembly casting by clamping

rings

66, 67, 68, 69

saw/91:

overlie'said flanges, so mar any cylinder can be rapidly removed for servicing simply by unbolting its clamping ring. So far as possible, the quantity of ex'- ternal air piping on the core-box support is reduced by providing air ducts in the body of the casting itself.

The

carriages

16, 17 with their core-box assemblies, are" propelled along the carriage rails by a pair of long pneumatic piston-and-cylinder units that are disposed longitudinally of the machine one on each of the parts of the fixed framework constituting the

wings

12, 13 and lie with their axes horizontal-and inalignmentI Part of'one'of the cylinders is seen inFigure 2 at 70.

The cylinders 70 and

carriages

16, 17 which they operate are operated alternately and the stroke of each cylinder is such that at maximum extension of the rod of one cylinder 70 the piston rod does not quite reach into contact with the parts of the other cylinder and piston rod which is in the retracted condition.

In order to" hold each carriage against lateral play as it travels along the track, each

wheel

44 or 45* of the earriage has associated with it apairof small rollers 171, 172 which are mounted below the main'wheel with their vertical and run against opposite sides of the rail r4591: 15, as seen in the detail, Figure 11.

4 Rollover of each core-box assembly on carriage from the upright to the inverted position, andback again, is aecomplished by a piston-actuated rack mechanism, shown in Figures 3 and 4 The rack 71 rneshes with a pinion 72 which is fast on the spindle 52 ofthe-outer anner oh the core-box support casting 20; The pinion 72 is situated in a housing 73 cast integrally with the "u "i" end of the carriage casting 1'6, and immediately w the pinion are the horizontal cylinder elements 253, 254 also cast integrally as part of the carriage casting 16. These extend transversely across the end of the carriage. The head cylinders" 253, 254 are united By a coaxialcylinder 74 which is tangential to the casing 73' and contains a long pneumatically-operated piston: 75 having two working heads, one at each end, and over a pd'rtion of its length intermediate its ends the long piston is recessed along its upper side to accommodate the toothed rack 71 already referred to. When air under pressureadmitted to one or other of the ends of the cylinder 74' to drive the piston 75, the pinion 72, and hence theicore-box support 20, is rotated through substanan 180.

The' piston 75 carries a small auxiliary bufier piston 76 which, toward the end of its stroke to the right as seen Figure 3', enters a small diameter cylinder 77 in a liner 78" housed in the cylinder 54, and thereby serves to eushion the rollover motion as the limit of travel in this direction is approached, so that the core-box support is Brought gently to rest" as it is inverted. V

In some modes of operation of the machine, it may be desired for the core-box support 20 to have, in addito its upright and inverted stationary positions,- a half-way position in the rollover in which it becomes stationary with the open top of the core-box facing out toward the operator, as seen in Figure 2. In ofder to" ob'tain the half-way position, the cylinder hous- 53 contains a larger piston 79 which has a plunger $0? passing through a fluid-tight gland 81 into the cylinder 74. As the rack piston 75' travels toward the left as viewed in Figure 4, it comes up against the plunger at about the halfway position of its travel, and if there is air pressure behind the larger piston 79 the rack piston 75' will be arrested in this positiori. After the rack piston has been arrested in this" manner, it may be allowed to complete the remaining half of its travel by exhausting the air from behindthe larger piston 79. The piston 79 and ca'r'ri'es a small butter piston 8 2 to enter a butter cylinder 83 in the head 84 of cylinder 53. p v

If desired, the caps of the trunnion bearings 46, 47 and pinion housing 73', can be made detachable so that the complete corebcx support 20 car he lifted from its carriage 16' without disturbing the rack piston 75 and cylinder 74 The air supply to the left-hand side of'the cylinder 75 and to cylinder 53 is by connections 90, 91 respectively. If air is admitted at 91 it will operate plunger and the core-box support 20 will roll half over; the rest of the stroke will wait until air is admitted at 90. The air supply to the right-hand end of cylinder 74' is by pipe 84 which connects with a conduit 85 in liner 78, having a branch $6 to buffer cylinder 77. The conduit 85 communicates with cylinder 74 through a ball valve 87 and also through a throttle valve 88 and passage 89. If air is admitted to pipe 84 it lifts ball valve 87 and enters cylinder 74 freely; it also enters buffer cylin der 77 and rolls the support 20 back with its full force-.- When pipe 84 is connected to exhaust for the initial rollover stroke by air admitted to connections 90, 91, how ever, the ball valve 87 closes and the speed of rollover is limited by the setting of throttle 38 as soon as biifie'r piston 76 enters cylinder 77. The return stroke at the other end is similarly buffered by the action of a' ball valve 92 and restriction valve 93. The throttle 88 is made With'a' hand wheel 94 as the speed of roll over with the core in place may call for special adjustment from time to time;

It will be understood that an interlock in the controls to

connections

84, 90, 91 is provided to block movement of the'carriage- 16 toward the blow station in the tower 11 if the core-box support 20 has not returned after roll over to the correct upright position, and this interlock may be also made to respond to the connections to

cylinders

53, 54, 63, 64 so that it also prevents movement of the carriage, if the core-box is not properly closed. Such interlocks in controls are common practice and need not be further described.

The pneumatic ram 18 that lifts each core-box sup port 20 on its carriage 16 toward the sand blowing head when it arrives at the central blow station in the tower" 11, has a large diameter cylinder 19 which projects underneath the main frame of the machine into a pit below floor level. The construction is shown in detail in Figure 12. The cylinder 19 is stopped, with a larger diameter upper portion 96 and a somewhat smaller diameter lower portion that extends down below floor level, and a long stepped ram 97 works in the cylinder, the ram being constituted in the main by a large casting with two external diameters to suit the two diameters of the

cylinders

95, 96; The top of the ram projecting through the open upper end of the cylinder has secured across it to close it a substantially rectangular platen 98 (see Figure 8) with a ribbed upper surface to carry the carriage 16 and core-box support 20, and this platen is extended out all round beyond the upper end of the cylinder to form a downwardly sloping hood 99 to prevent sand from entering the

cylinders

95, 96 below it. At the back of the cylinder the shroud ring has cast integrally in it a boss 100 with its axis vertical, and the boss receives the upper end of a single stout guide rod 191 that slides vertically in a bearing 102 secured externally to the back of the cylinder, to prevent any twisting of the ram 97 as it is raised and lowered with the carriage 16 and core-box support 20 supported on it. The hood 99 on the platen is extended out far enough at the back to cover the top of the guide rod bearing.

As has been previously explained, the core-box support 20 in the tower 11 is lifted up to a sand box 39 for delivery of the sand-mix to the core box during the core blowing operation, and the sand box 30 is movable in the fore-and-a-ft direction along rails 32 from the blow ing position to a position beneath a chute leading from a sandhopper for replenishment after each blow. The sand box is mounted on a one-piece carriage casting 31 which has wheels 105 to run along the horizontal track 32 previously mentioned. The carriage has two sets of wheels displaced slightly in the vertical direction with respect to one another, the lower-set 105 running on the rails 32 below the wheels to bear the weight, while the upper set 106 bear on the underside of the upper rails 32, whereby the carriage is held against any vertical movement. By providing two sets of wheels at slightly different levels in this Way, the friction and possible binding that would occur the same wheels were in contact with both upper and lower rails is obviated. The carriage casting 31 of the sand box assembly is in the form of an open rectangular frame, and the sand box 31 is carried in the opening of frame 31 upon vertical guide rods 107 which work in bushing 16% (see Figure 9) in the frame 31 and allow the sand box St to perform a limited vertical movement with respect to the carriage. In order to close off the lower end of the delivery chute 33 from the hopper when sand-mix is not required to be delivered through chute 33 to the sand box 30, a horizontal shut-oif valve-plate 109 is provided, carried by the chute 33 so that it comes between the sand box 30 and the chute 33 above it (see Figure 8), that is to say the upper face of the plate is sealed against the lower face of the chute 33 while its lower face is against the upper end of the sand box 30. Immediately in front of the delivery chute 33, over the position which the sand box occupies during core blowing, is a blowing head 111 having at its base a casting 110 containing two ducts 112 (see Figure 9) by which air under pressure is supplied to the upper end of the sand box during blowing. The shut-off plate 109, as well as being below the sand delivery chute 31 when the sand chamber is in the core blowing station, also has a portion which extends forwardly beneath the blowing head 111, where it has an aperture through it to permit entry of the air under pressure to the sand box. This part of plate 109 is preferably made as a distinct piece linked to the other portion but capable of slight up and down movement. When the core-box support 211 is clamped up against the underside of the sand box 39 for blowing not only is a seal made between the core box and the lower face of the sand box, but also the sand box itself is lifted slightly on its guides 107 to make a seal between its upper end and the plate 1119 and between plate 109 and the blowing head casting 110.

The sand box carriage 31 is movable along its track by a pneumatic cylinder (not shown) mounted at the back of frame of tower 11 with its axis extending parallel to rails 35 and midway between them.

A further pneumatic cylinder moves the squeeze pin assembly 34 which, as previously described, comes in beneath the sand box and above the core-box after the sand-mix has been blown into the core-box, along rails 35. The squeeze pin assembly comprises a carriage 115 (see Figure 9), also in the form of an integrally cast one-piece rectangular frame, having

wheels

116, 117 to travel on the track 35 for the squeeze pin assembly, and three vertical rods 36 depending from the carriage and slidable in bearings thereon, which rods carry at some distance below the carriage a horizontal plate 118. The

wheels

116, 117 of the squeeze pin assembly carriage are in two sets at slightly different levels to bear against upper and lower rails 35 in similar fashion to the

wheels

105, 1% of the sand box carriage 31, so as to hold the carriage against vertical displacement. Mounted just below the carriage and above the rising plate 113 already mentioned is a further horizontal plate 119 which carries a number of vertical squeeze pins 121 that extend down through bashed holes in the rising plate 118 and are a sliding fit therein. Oniy two pins 120 are shown, in chain line, as it will be understood their number and placing depend on the circumstances of the design of core box which may be in use. The upper ends of the depending rods 36, which pass through the slide bearings 121 on the carriage 115, have heads 122 above said bearings that come immediately below three vertical air-spring 8 cylinders 123 carried by external brackets-124 on the walls of the sandbox, when the squeeze pin assembly 34 is run in beneath the sand box 30.

When, after blowing a core, the squeeze pin assembly 34 is run in above the core-box support, and the latter is raised toward the squeeze-pin assembly, the top of the core-box engages and lifts the rising plate 118 of said assembly, bringing the heads 122 on the rods carrying said plate'into co-operation with pistons in the air-spring cylinders 123. The rising plate and rods are pushed upward against the resistance of the air-springs and the squeeze pins on the upper plate of the assembly which is unable to rise above the bottom of the sand box, project progressively further through the holes in the rising plate and are forced into the sand in the core-box, thereby providing the desired sand-ramming action necessary to squeeze the sand tightly into all the cavities of the core-box. By using high pressure air-springs 123 to resist the upward travel of the rising plate of the squeezepin assembly, in conjunction with a pressure regulator in the air line (not shown) to the air-springs, the amount of penetration of the squeeze pins into the core-box can be precisely controlled by adjusting the balance between the upward thrust of the main core-box assembly lifting cylinder 19 and the downward pressure of the air-springs. The control afiorded in this way is a considerable improvement on the use of ordinary coil springs, and the pressure as between one spring 123 and another is automatically equalised.

The air under pressure for blowing the cores is derived from an air reservoir, through two similar air blowing valves 125 at the top of the tower. Each air blowing valve 125 delivers into one of two ducts 126 leading down through the blowing head 111 to ducts 112, and each duct 126 has an entry at its upper end above which is situated a large valve box 127 controlled by a doublediaphragrn valve 128. The entry of duct 126 faces upwardly, and the diaphragm valve 128 is disposed horizontally and immediately above duct 126. The valve consists of two diaphragms 129 of rubber with a valvedisc 128 between them and is able to fiex up and down toward and away from the duct 126, the upper end of which forms a valve seat. The air to be delivered through the duct is admitted to the annular space 130 in the valve box around the duct 126 below the diaphragm 129. A coil spring 131 in the valve box 125 above the diaphragm bears on top of it and urges it down to close the duct, while the pressure in the air space 130 surrounding the duct acts on the underside of the diaphragm assembly and tends to urge the diaphragm up. There is also a connection 133a for air under pressure to a space 132 in the valve box 125 above the diaphragm assembly, and by suitably varying the pressure in this space the diaphragmvalve' 128 can be caused to open and close, and thereby admit and shut-01f air to and from the blow ing head. The diaphragm valve lifts away from the duct entry with a quick snap action. This is due to the fact that the pressure, up to opening, acts only in the annular space 130 and has to be adequate to overcome spring 131. When the valve opens pressure obtains access to the whole area of the valve and snaps it upward. On closing, the pressure-area is again restricted to the annulus and the spring 131 holds the valve firmly seated. This enables the period of opening to be made very definite.

There is also a second small separate air cylinder 133 for operating an exhaust valve 134 on a branch 135 from duct 126 to permit residual high pressure air to escape after the diaphragm valve 128 has closed.

The valve assembly 125 is clamped on to its valve box seating 127 around the air duct 126 by studs 136 of which one only is shown in the drawing. In order to allow the valve assembly 125 to be dismantled and reassembled rapidly, the studs do not pass through the valve assembly itself but instead the head is provided with outwardly extending lugs 137 which project beyond the valve and its b6x'12'7, and the studs'137'p'a's's through these lugs. In ordef'to' all'owf removal of the valve as"- sembly without the need for dismantling any of the air connections, the air" supply to the space above the diaphragm is brought into the valve box 111 and is then taken by the internal .ducts 133a up through the clamped edge of the diaphragm valve and thence to the upper side of the diaphragm:

Referring now to- Figure-; the draw saddle4l] that received the cores from its associated core-box support 20 after the latter is inverted above it, is operated by an hydraulic cylinder 1-40- mounted with its axis vertical in the lower part of the structureof the appropriate wing of the machine frameand extending down into: a pit below floor level. Near its upper end the draw cylinder 140 has: cast integrally on opposite sides of its exterior two substantial" l'tifiil' Wiiig brackets 141 which carry vertical slide bearings 142 for two long guide rods 143. The ram 144 working in the cylinder 140 carries the head 40 at its upper end above the cylinder. The head 40 extends outwardly and downwardly to form a shroud 145 or cover and prevent stray sand entering the cylinder 140, and this cover is extended out in opposite directions to positions where it is formed with a pair of bosses 146 in which the upper ends of the guide rods 143 are secured.

The core-carrying platform 41 of the draw saddle comprises two parallel horizontal support rails 147 which are carried on the upper ends of four vertical rods 148 that are independently supported by springs 149 and pass downwardly through dashpots 150 mounted on the cap 40 of the ram. The rails 147 are pivoted to the rods 148, and the springs 149 and dashpots 150 allow relative vertical movement of the rods. The support rails carry a drier plate 151 which the operator places on them and when they bring it up against the underside of the corebox in the inverted support 20, the rails automatically adjust themselves to suit the attitude of the core-box even though the latter may be somewhat out of the horizontal. This enables the core to be deposited on the drier plate 151 without shock. As has been hereinbefore described the part of the core-box having the cylinder cavities does not open and the barrels on the core have to be carefully withdrawn from these cavities; at this stage, before baking, the sand core is still fragile and can easily be broken and the absence of shock is important.

Moreover, in view of the fragility of the core, the rate of withdrawal of the core, that is to say the downward speed of the draw saddle 40 and drier plate 151 which it carries must be suitably controlled. To this end the lower end of cylinder 40 is connected to a supply pipe 152 which leads to a control including an oil damping valve (not shown) which provides for a slow descent of plunger 144 when stripping the core from the core-box, followed by a more rapid downward movement after a time and finally a slow finish to the stroke. The stroke terminates in a cushioned stop by reason of an extension 153 on the bottom of the plunger 144 entering a cushion ing cylinder 154 which forms an extension of the cylinder 140. The cushioning cylinder 154 contains a bypass 156 with a ball valve 155 in it and the extension 153 of the plunger has tapered flutes 157. In operation, when the ram 144 descends and the extension 153 enters the cushioning cylinder 154, oil is trapped in the bottom of cylinder 144 beneath the piston 158. It can only escape to pipe 152 through the flutes 157. These damp the motion and cushion the stop. The draw saddle rails 147 are shaped to fit the drier plate 151. Their spacing should be adjustable for different-sized plates and to this end the spring plungers 148 and dashpots 150 are on bases 160, adjustable along T-slots 161 along the sides of hood 145.

The forks 44 on the swing-out arm 42 (Figure 1) for removing the cores from the draw saddles are shown in Figures 13 and 14. A hand lever 163 on each swing-out arm is articulatedfbya' link 1 41b: parallel linkage its 1 66 supporting the haf t 1 6 7' of the fork on the Operation of hand-lever 163 therefore raises or lowers the fork. A fixed handle 1'68ena'b1es the arm 42 to be swung. There is a catch' on the hub 169 of the 42; which" engages a stopope'rated' by a hydraulic lock 173 to prevent the arm from being swung in until the corresponding draw" saddle is fully down. The fork arms 44areadjustable on a bar 174 on the haft 167 for width to 'suitdilferent core sizes; I

Thus, in use, after a'core-box has been inverted over adrier plate 151 and the drier plate has been raised by plunger 144 into contact with the core, the core-box is opened operating

cylinders

53, 54 first to withdraw platens57, 58 andjcylinders' 63, 64 after them to withdr'a'w platens 65, 66. Tliecor'e will then be supported against gravity by the drier plate, which is gently' loweredi The core-box support is then turned up again and the arm 42 is swung in which the handle 163 in the forward position shown in Figure 13, that is to say with form 44 lowered. The arms of the fork, if properly spaced, will miss the bars 147 and enter the space below the drier plate. The handle 163 is then operated to lift the fork 144, which raises the drier plate and core off the bars 147, and the core can then be swung out of the machine and placed by the operator, still on its drier plate, on a conveyor which carries it off to a drying oven.

Although in the method of operation described, the drier plates 151 to receive the cores are placed on the draw saddles 40, it may be preferred instead to stop the rollover of each core-box support 20 in the halfway position shown in Figure 2 with the core box top facing out toward the machine operator, and to place the drier plates 151 direct on to the core-boxes in this position before the core-box support is fully inverted. In this case permanent magnets would be provided on the corebox support 20 for holding the drier plates in place during inversion.

It will be appreciated that, in filling sand into the sand box 30 from the chute 33 (Figure 8), the sand must be supported and in blowing sand from the sand box 30 into the core-box below it this sand must be able to flow downwardly; to this end in the bottom of the sand box there must be a blow-plate, indicated by casting 180, Figure 9. This plate must be designed to suit the core in use and has blowing holes running through it at positions where it is suitable to direct streams of sand into the core box. The sand will bridge the holes when let in by chute 33 but will be blown through when pressure is applied by air valve 125. After the core has been filled and when it is lowered away, some clods of sand may tend to fall out of the blowing holes onto the base of the core and spoil its surface. To minimise this trouble the blowing holes in plate are preferably tapered so as to be smallest at the bottom.

I claim:

1. In a foundry core-blowing machine, the combination of a sand-box at a filling station for holding a charge of sand-mix, rails extending transversely to the box, a core-box carriage in the form of an open frame movable on the rails to and from the filling station, a core-box support mounted on trunnions on the carriage so as to swing for inversion in the open part thereof, a pinion coaxial with the trunnions on the core-box support, a cylinder extending across the trunnions of the frame, a piston therein and a rack meshing with the pinion and connecting the piston thereto to effect inversion.

2. In a foundry core-blowing machine the combination as claimed in claim 1 wherein the piston is a long piston tangential to the pinion and carries the rack between its two ends.

3. In a foundry core-blowing machine the combination as claimed in claim 1 wherein the axis of the trunnions is parallel to the rails.

4. In a foundry core-blowing machine, the combination of a sand-box at a filling station for holding a charge of sand-mix, a core-box carriage transportably mounted to move into the filling station and away therefrom to a removing station, a core-box invertibly mounted on said support to be inverted to discharge cores when transported to the removing station, means to hold a drier plate at the removing station below the core-box support to receive the cores, and means to remove the drier plate comprising a fork mounted on a movable carrier for insertion beneath the drier plate, means to lift the fork relatively to the carrier and means to withdraw the carrier from the machine. v

5. A foundry sand-blowing machine as claimed in claim 4 wherein the movable carrier consists of a swinging arm shaped to enter the machine without fouling the carriage for the core-box support and parts for supporting the same.

12 6. A foundry sand-.blowingmachine, as claimedin claim 5 wherein-the swinging arm carries an interlock member so that it cannot be swung in until the carrier plate has been lowered away from thecore-box support.

References Cited in the file of this patent UNITED STATES PATENTS 1,492,353 Campbell Apr. 29, 1924 1,595,600 Demmler Aug. 10, 1926 1,717,325 Ryan June 11, 1929 2,545,944 Ellms Mar. 20, 1951 2,559,647 Legere July 10, 1951- 2,640,234 Bergami June 2, 1953 2,791,012 Miller May 7, 1957 FOREIGN PATENTS 7 200,254

Australia Nov. 11, 1955