US3916982A

US3916982A - Sound attenuating improvements for foundry molding machines

Info

Publication number: US3916982A
Application number: US314377A
Authority: US
Inventors: Warren A Blower; Harry R Nara
Original assignee: Sherwin Williams Co
Current assignee: Sherwin Williams Co
Priority date: 1972-12-12
Filing date: 1972-12-12
Publication date: 1975-11-04
Anticipated expiration: 1992-11-04
Also published as: JPS5649172B2; FR2223111B1; FR2223111A1; CA1011079A; DE2354538A1; GB1445749A; JPS4989628A; IT999930B

Abstract

Jolt foundry molding machines incorporating specially constructed jolt impact receiving surfaces and exhaust and valve systems which achieve the required jolt impact to make satisfactory foundry molds while nevertheless attenuating the noise normally produced by such machines as required by the Occupational Safety & Health Act Standards.

Description

United States Patent Blower et a1. 1 1 Nov. 4, 1975 SOUND ATI'ENUATING IMPROVEMENTS 2,561,726 7/1951 (3116mm 181/36 R FOR FOUND MOLDING MACHINES 2,984,529 5/1961 Dailey 1 1 92/85 3170,3175 9/1966 Young 1 1 1 4 4 164/206 1 lnvemorsl Warren Blower, Brecksvllle; 3,450,037 6/1969 1161mm et 211.1 ,1 92/85 Harry R. Nara, Novelty, both of 3.537543 11/1970 011381 181/36 A 01110 3,589,432 6/1971 Miller .1 164/39 3,658,118 4/1972 Abraham 164/39 [73] Asslgneel The sherwln-wllllams Companh 3,703,125 11/1972 Pauliukonis .1 92/249 Cleveland, 01110 3,724,502 4 1973 Hayner .4 181/36 R [22} Filed: Dec. 12, I972 FOREIGN PATENTS OR APPLICATIONS [21] Ap l. No.: 314,377 863.078 3/1961 UniICd Kingdom 164/197 610,265 1/1932 German 164/206 52 us. 01 164/206; 164/197; 91/216 B; Emmmekpaul E. Maslousky 91625; 92/85? 181/36 R Artur/1e1 Agem, or Firm-D0nr1el1y, Maky, Renner & (51] Int. Cl. ,1 B22C 15/18; B22C 15/14; Om)

FO1B15/O0;F01L 21/02 [58] Field of Search 92/85. 117 R, 217. 250, 7 AB T T 92/249;91/216 B,216 R,216 A. 325; [5 I S B [64/206, 2031 39 261, 196 197; 181/36 A Jolt foundry m0l d1ng machn es mcorporatmg specially 36 R, 7! constructed olt lmpact recewmg surfaces and exhaust and valve systems which achieve the required jolt im- [56] References Cited 56c; t0 nxike SiIISfHfiiOT) feundry moulds whjjle nave:-

eess a enua mg e no1se norma y pro uce y UNITED STATES PATENTS such machines as required by the Occupational Safety 989,971 4/1911 Herman 164/206 & Health Act Standards, 1,459,221 6/1923 Krause 164/206 2,499 018 2/1950 Christiano .1 181/71 26 Claims, 8 Drawing Figures -85 j I -78- 73- f l 87 74- Z 86 m 77 U.S. Patent Nov. 4, 1975 Sheet 2 of6 3,916,982

US. Patent Nov. 4, 1975 Sheet 3 of6 3,916,982

US. Patent Nov. 4, 1975 Sheet 4 of6 3,916,982

U.S. Patent Nov. 4, 1975 Sheet 5 Off) 3,916,982

g/lv

SOUND AI'IENUATING IMPROVEMENTS FOR FOUNDRY MOLDING MACHINES This invention relates generally as indicated to sound attenuating improvements for foundry jolt molding machines and more particularly to improvements in the construction of the strike or impact surfaces of such machines as well as improvements in the exhaust and valve systems.

Foundry jolt molding machines normally operate at sound levels in the range of I to I decibels A"Scale (dbA). Most sound in such machines is nor mally created by two sources, the first being the metalto-metal strike of the jolt impact, while the second is the air exhaust, air under pressure being required to operate the jolt mechanism and other components of the machine.

Foundry jolt molding machines nomially involve relatively moving massive metal parts which impact against each other to obtain the jolt action. Jolt impact surfaces have in the past been provided with wearresistant, non-metallic coverings. These have not appreciably affected the sound levels of the operation of the machines.

Applicants have found that by providing the jolt impact surfaces of the squeeze ram or jolt ram with specially constructed elastomeric inserts, the noise level attributable to the jolt impact can be significantly reduced while still nonetheless providing sufiicient impact forces to obtain dense, firm and uniformly packed foundry molds of the highest quality. In the case of the jolt ram which normally provides a center strike for the sand-filled flask supporting table, a large volume elastomeric insert is provided in the ram to receive the impact. In the case of an annular or outside strike with the table dropping onto the squeeze piston, a relatively large volume elastomeric ring is provided. It has been discovered that the hardness of the elastomeric material utilized should vary inversely to the area of the strike impact. For example, when the strike is on an an nular ring, the area of the strike is substantial and the material should normally be fairly soft. Conversely, when the strike is in the center of the table or squeeze head, the area of impact is relatively small and the hardness of the material should be significantly increased. Not only must the hardness and volume of the insert material be carefully controlled but the material itself must be carefully selected to avoid undue softening and wear upon repeated impacting in operation. The volume of the insert is also a factor in dissipating heat resulting from repeated impacting which can cause softening.

In the exhaust system special mufflers or sound filters are employed in conjunction with specially designed porting for the exhaust, the latter preferably leading to an expansion chamber before being ported to atmo sphere.

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 here inafter fully described, the following description and the annexed drawings setting forth in detail certain il lustrative embodiments of the invention, these being indicative however, of but a few of the various ways in which the principles of the invention may be employed.

IN SAID ANN EXED DRAWINGS:

FIG. I is a fragmentary vertical section of one embodiment of the present invention illustrating a machine providing both an anvil jolt and shockless jolt during squeeze;

FIG. 2 is a fragmentary vertical section taken sub stantially on the line 22 of FIG. I illustrating the exhaust expansion chamber in the housing with laterally extending exhaust ports therein;

FIG. 3 is a vertical section of a machine similar to that of FIG. I but illustrating a different exhaust porting arrangement for the jolt with the exhaust ports extending through the annular anvil jolt strike ring; the exhaust porting also being connected to the lower chamber;

FIG. 4 is a horizontal section taken substantially on the line 44 of FIG. 3 illustrating the arrangement of the exhaust ports in the strike ring;

FIG. 5 is a vertical section taken through the table of a somewhat larger machine of the type which may be used, for example, in automatic lines;

FIG. 6 is a vertical section of a machine having a modified form of squeeze cylinder ram providing both an annular outside anvil jolt and a center strike shockless jolt;

FIG. 7 is a fragmentary vertical section of an over head squeeze head incorporating a jolt ram and provided with some of the sound attenuating improvements of the present invention; and

FIG. 8 is a vertical section of a machine similar to that of FIG. 6 but utilizing the center strike only for both anvil jolt and shockless jolt during squeeze.

In describing the various embodiments of the present invention particular attention will be paid to the sound attenuating improvements incorporated in the various machines illustrated and the details of such machines will be described only to the extent thought necessary to provide the proper environment for the improvements of this invention.

With reference to FIG. I there is illustrated a machine having a base 10 which includes an upstanding cylindrical housing 11 in which is mounted squeeze piston 12. Such squeeze piston includes an upstanding cy lindrical portion I3. Projecting into the cylindrical extension ]3 of the squeeze piston I2 is a cylindrical extension 14 depending from table 15. The table is adapted to support a sand-filled pattern containing flask. Normally a squeeze head is positionable above the table, such squeeze head engaging the sand within the flask as the table is elevated to form the foundry mold.

Positioned interiorly of the table cylindrical extension 14 is a ram 16 which includes a lower reduced di ametcr extension I7 which extends through a central opening in the squeeze piston formed by the outwardly extending central cylindrical portion 18. The extension I7 in the down position of the table is supported on the base 10 and there is provided a slight clearance indicated at 20 between the top of jolt piston and the underside of the table thcreabove. The table in such down position is supported solely on the annular top of the cylindrical extension 13 of the squeeze piston. In such down position the squeeze piston 12 is bottomed on the housing It) as indicated at 21.

In operation, to obtain an anvil jolt or a dropping of the table against the machine base, air under pressure is supplied through passage 23 in the table which enters chamber 24. In the down position of the table poppet valve member 25 is in its up position compressing spring 26, the spring and valve member surrounding poppet guide 27, the cap 28 of which is secured to the table by fasteners 29. In the down position of the table the valve member 25 is unseated from the shoulder 30 and accordingly air from the passage 23 will pass into chamber 31 between the ram 16 and the table 15. When air is thus admitted to the chamber 31 the table is lifted off strike ring 32 on the top of the squeeze piston cylindrical extension 13. As the table elevates the spring 26 will cause the poppet valve member to move downwardly against the seat closing the air inlet to the chamber 31. Even though the valve member 25 is closed, the table will continue upwardly due to both the pressure in chamber 31 and the momentum of the table. The table continues upwardly until annular slot 34 in ram 16 communicates with transverse exhaust ports 35 in the table cylindrical extension 14. The annular groove 34 is in communication with the chamber 31 through a plurality of vertical slots 36. The exhaust ports 35 in the table cylindrical extension 14 are in communication with vertically elongated shallow groove 37. Such groove extends downwardly from the exhaust ports 35 and provides communication between exhaust ports 35 and exhaust ports 38 in the squeeze piston cylindrical extension 13. The exhaust ports 38 communicate with a further elongated groove 40 in the outside face of the extension 13 of the squeeze piston. The purpose of the elongated slot 40 is to provide communication between the exhaust ports 38 and exhaust slots 41 in the housing wall 11. Such slots 41 are three in number as seen in FIG. 2 and provide communication between the elongated groove 40 and exhaust chamber 42. The

side walls

43 and 44 of the exhaust chamber are provided with

enlarged exhaust ports

45 and 46, respectively, which are covered by exhaust screens or

mufflers

47 and 48, respectively, each of which is secured in place by screen clamp ring 49 which is in turn secured by the fasteners 50. The exhaust screens or mufflers may be of the compressed metal fiber type which have been found effective to reduce air exhaust noise in combination with the exhaust arrangement shown.

When the annular groove 34 communicates with the exhaust port 35, air from the chamber 31 will then exhaust to atmosphere through the exhaust chamber 42. The table then drops onto the strike ring 32. When the table drops the valve member 25 is again opened repeating the jolt operation as long as the jolt valve is open supplying air pressure through the line 23. In the illustrated embodiment, the valve member 25 will travel approximately three-eighths of an inch to its closed position while there is approximately 1 inch of travel required to provide communication between the slot 34 in the jolt ram and the exhaust ports 35. This arrangement reduces the volume of air required to perform the jolt action and accordingly also reduces exhaust noise.

Now. to jolt during squeeze, air is supplied through pipe flange 52 pressurizing the chamber 53 beneath the squeeze piston 12 through passage 54. This elevates the squeeze piston and of course the table 15 supported on the strike ring 32. Jolt ram 16 is also elevated by the air pressure within the chamber 53 since the extension 17 thereof is exposed to the pressure within such chamber.

This of course will move the jolt ram against the bottom of the table 15 opening the poppet valve member 25. Again when air is supplied through the passage 23 to the chamber 31 the jolt ram 16 will descend first closing valve member 25 and then providing communication between the slot 34 and the exhaust ports 35 venting the chamber 31. The squeeze pressure beneath the jolt ram extension 17 will then cause the ram to move upwardly striking the bottom of the table on the underside of the frusto-conical projection 55. This action will continue as desired as the table is elevated against the squeeze head compressing the sand within the flask supported on the table.

The exhaust system of the machine of FIG. 1 which utilizes: the short stroke poppet 25; a reduced volume chamber 31 with vertical slots and an annular slot 34 comprising a part of that chamber; a plurality of exhaust ports 35 (in the illustrated embodiment preferably six in number); the exhaust ports 38 and the exhaust slots 41 communicating with the exhaust chamber 42 provided with cover 56; and the enlarged later ally extending

exhaust ports

45 and 46, has been found effectively to reduce the noise level of such machine caused by the jolt air exhaust. For comparative purposes references may be had to US. Pat. No. 3,658,1 18 to Abraham dated Apr. 25, 1972, showing an exhaust system of a prior art machine. While all of the above factors are believed to contribute to the reduced noise level, one point of some significance is believed to be the ratio of the cross-sectional area of the exhaust ports 35 as compared to the cross-sectional area of the

exhaust ports

45 and 46. In the illustrated embodiment the latter two provide a cross-sectional area of approximately 14.1 square inches while the cross-sectional area of the six exhaust ports 35 provide a crosssectional area of approximately 4.7 square inches. This provides an area enlargement in a ratio of approximately three to one.

To reduce the noise level normally generated by the usual metal-to-metal impact of a jolt mechanism, the strike ring 32 is made of a urethane elastomer and includes a mounting ring 58 which is secured to the top of the squeeze piston extension 13 by suitable fasteners 59. To reduce the noise level of the center strike, the jolt ram 16 is provided at its top with a cavity 61 in which is secured a large volume molded urethane insert 62. The insert is secured in place by a retaining ring 63 which fits over the shoulder 64 on the insert. The insert is provided with a frusto-conical top projection 65 having the same area as the projection 55 on the table. A tapped aperture 66 is provided in the top of the insert to facilitate the insertion of a lifting eye so that the insert may be readily removed. In the illustrated embodiment the insert 62 may, for example, have a diameter of approximately 6 inches and also a height of approximately 6 inches. Thus the insert is quite massive. The volume of the urethane insert 62 is believed to create some form of heat sink which in combination with the ram structure maintains the insert sufficiently cool to prelude undue softening. For example, a urethane insert pulled after use has felt cold on the outside but the center of the insert was measured at about 200 Farenheit by the use of a thermocouple. Jolt air passing from the chamber 31 down the vertical slots 36 and into the annular slot 34 apparently extracts heat from the insert, the clearance between the insert and the surrounding jolt ram being just sufficient to insert and remove the insert 62.

For the center strike insert 62 which has a relatively small strike area it has been found that a relatively high hardness is required of from about 65 to 72 on the Shore D scale and preferably about 70 while the strike ring 32, having a much larger impact area may have a hardness of approximately 60 to about 95 on the Shore A scale. This is of course relatively soft. With the hardnesses noted it has been found that sufficient impact is still obtained to produce high quality molds while reducing the noise level to less than 90 decibels (dbA). As indicated, normal metal-to-metal impact in such machines generally run from around 110 to I decibels (dbA).

The inserts of this and subsequently described embodiments may incorporate suitable heat transfer fillers in suitable amounts (approximately 25-50%). Fillers which have been found to function acceptably are lami nar fillers such as aluminum chips, iron or flake aluminum. Also acceptable are graphite granules or coarse bronze wool, for example. It has been found that the insert can be molded in steps with the heat transfer fill ers placed alternately between the steps. For example, the uncured elastomer may be poured in the mold to a certain height and then aluminum chips may be Iayed on top of that portion poured. The pouring and placement of the filler is then alternated until the insert is completely molded. Circular discs of aluminum or cop per screen of suitable mesh to permit the elastomer to flow therethrough may be used. In any event, the filler is then confined to vertically spaced horizontal layers. It is believed that such fillers act to absorb and transmit heat from the center of the insert which results from the hysteresis loss of the material. The temperature is of course a factor in the properties of the material and the fillers are believed to maintain the properties at acceptable levels.

In FIGS. 3 and 4 there is illustrated another embodiment of the invention utilizing a different exhaust system to obtain the requisite noise control. In such embodiment the machine includes a housing 70. squeeze piston 71 mounted therein for vertical reciprocation, table 72 having a cylindrical skirt 73 telescoped into the cylindrical extension 74 of the squeeze piston and jolt ram 75 mounted for vertical reciprocation in the table extension 73. The jolt ram includes a reduced diameter extension 76 extending through the squeeze piston so that the lower end of the extension 76 is exposed to the chamber beneath the squeeze piston. The jolt ram is provided with a cavity 77 in which is secured the large volume urethane insert 78 while the top of the cylindrical extension 74 of the squeeze piston 71 is provided with urethane strike ring 79 secured through mounting ring 80 by the fasteners 81.

Air for the jolt action is obtained through the poppet valve assembly 82. As the table elevates, the air from the chamber 83 above the jolt ram passes downwardly through slots 84 into the annular slot 85 and outwardly through exhaust ports 86 in the table extension 73.

The exhaust ports 86, which again may be six in number as in the FIG. I embodiment, communicate with an annular groove 87 in the interior of the extension 74 of the squeeze piston 71. The extension 74 also has a series of vertical grooves 88 therein which extend vertically along the interior thereof. the lower ends communicating with the chamber 89 beneath the table extension 73 and the enlargement of the jolt ram 75. As seen more clearly in FIG. 4, three of the vertical slots 88 communicate with paired exhaust ports seen at 91. Such exhaust ports extend vertically in the annular strike ring 79 and the mounting ring with the latter being utilized to hold muffler screens 92 in place. It will be appreciated that additional exhaust ports may be provided extending vertically through the strike ring 79. Such exhaust ports will of course be opened as the table is elevated from the strike ring permitting air to escape beneath the relatively shallow skirt 93. The combination of the muffler screens 92, which are the same type as employed in the FIG. I embodiment, together with the large number of exhaust ports has been found effectively to reduce the air exhaust noise.

One point of note which is illustrated perhaps most clearly in FIG. 4 is that the urethane large volume insert 78 which receives the center strike of the jolt ram is provided with a transverse top slot 94 which precludes an air seal between the ram and the underside of the table.

Referring now to FIG. 5 there is illustrated the head ofajolt and squeeze machine which may be utilized for example in automatic lines. The machine includes a table 96 which is supported on springs, not shown, on vertically movable guide head 97 which is in turn supported on the upper end of tubular piston rod 98. The piston rod 98 extends through fixed cylinder head 99 from the cylinder I00 of the vertically extending piston cylinder assembly by which the table 96 is raised and lowered.

.lolt guide pins I02 and I03 are secured to the guide head 97 and extend through suitable bushings in both the table and the cylinder head as indicated at 104 and 105, respectively. A jolt ram 106 includes a lower re' duced diameter extension I07 which is spring supported and piloted in the tubular rod 98. The jolt ram is mounted in cavity I08 in the table and a suitable piston ring is provided indicated at 109. The table includes a cylindrical skirt I I0 formed by the cavity 108. Air for the jolt is supplied through the poppet valve assembly III pressurizing chamber 112. The chamber I I2 includes vertical passages I I3 communicating with annular groove II4 so that when the table and ram move relative to each other and the groove 114 is exposed to exhaust ports I IS the chamber "2 will be exhausted. The exhaust ports I I5 are closed by plugs 1 l6 and inverted T-passages I17 connect the exhaust ports [I5 to chamber "8 through their open legs.

The chamber 118 is formed by ring II9 mounted on annular plate I20 secured to the guide head 97. The top of the annulus H9 is provided with a beveled ring I2], the ID. of which has a rather close clearance with the OD. of the skirt H0. The annulus H9 is provided with a plurality of exhaust ports I22 each of which has secured therein muffler screens I23 of the type illustrated in the embodiments of FIGS. I and 3.

Jolt ram I06 is provided with a large volume ure thane insert seen at I24 held in place by the retaining ring I25 as in the embodiments of FIGS. I and 3. In this embodiment the insert I24 is provided with two dia metrical intersecting passages I26 and 127 at the bottom thereof. Each of the four radially extending passages thus formed is provided with two vertically extending passages as seen at 128 and 129, or eight such vertical passages altogether. .Iolt air from the chamber H2 is accordingly required to pass downwardly through the insert to exhaust through passages l 13 during jolt. This accordingly more directly removes heat from the insert which would be generated by repeated jolt impact.

The chamber 118 acts as in the FIG. 1 embodiment as an expansion chamber reducing the exhaust pressure through the ports 122 and together with the muffler screens in a series of exhaust ports substantially reduces the noise level caused by the exhaust. For example, there may be 12 exhaust ports 122 in the annulus 119 thus increasing the cross-sectional area of the ex haust ports by the factor of approximately 3 to l indicated above. The machine of FIG. has been found to produce high quality foundry molds with substantially reduced noise levels.

in FIG. 6 the machine includes a table 132 having depending cylindrical extension 133 which tits within cylindrical liner 134 mounted on and secured to shoulder 135 on the interior of the cylindrical extension 136 of the squeeze piston 137. The cylindrical extension 136 includes a top flange 138 which in the table down position seats on the top [39 of the cylindrical portion [40 of the base 141.

A jolt ram 143 in the table down position is supported on ram extension 144 which extends through sleeved aperture 145 in the piston 137. The end of the extension is provided with a lip [46 which precludes the extension from popping through the aperture when the squeeze piston is pressurized.

For jolt action air is admitted from the passage 148 through unseated poppet valve 149 into chamber 150 above the jolt ram. In the table down position. the urethane insert 15] engages the poppet valve member 149 unseating the same. Jolt air pressure in the chamber 150 elevates the table until groove [52 communicates with exhaust ports 153 in the table extension 133 per mitting the jolt air to escape into vertical grooves 154. The vertical grooves 154 are provided with ports 155 communicating with annular chamber I56 which in turn communicates through passages 157 with chamber [58 beneath the table extension 133 and the jolt ram 143.

The chambers I58 and 156 act as expansion chambers reducing the air pressure impact on exhaust ports 160, each of which is provided with a muffler screen as indicated at 161. in the illustrated embodiment of PK]. 6, there may. for example. be eight such exhaust ports 160. Such exhaust ports permit the air to escape into chamber 162 and then over the top of the annular strike ring 163 to atmosphere. Radial grooves 164 may be provided in the top of the strike ring to exhaust chamber [62 during simultaneous jolt and squeeze. Such ring is held to the flange 138 of the squeeze piston by fasteners 165 extending through mounting ring 166.

A jolt guide pin [67 is mounted in table 132 and ex tends into bushing [68. A limit pin [69 is mounted in the cylindrical extension 140 of base 141 extending into closed-end slot in the CD. of cylindrical extension ]36 of squeeze piston 137. The pin 169 pre cludes ovcr-stroke of the table. Additionally, overstroke ports may be provided in the liner to preclude the table from popping out.

The large volume urethane insert 151 includes a somewhat higher frusto-conical portion 172 than the inserts of the other embodiments. such frusto-conical portion projecting from a cylindrical base 173'. retaining ring 174 engaging the top of the base to hold the in sert in place in its cavity. This permits the vertical grooves 175 extending between the chamber 150 and the annular groove 152 to be foreshortened. The insert 151 is also provided with the threaded aperture 176 permitting a lifting eye to be inserted so that the insert may be removed. Transverse passage l77 communicating with the aperture 176 serves the same function as the transverse slot 94 seen in FIG. 4.

In the operation, with the table down. the table will be jolted on the annular strike ring 163 due to the clearance between the top of the center insert 151 and the underside of the table. At the peak of the strike the compression of the ring 163 may also cause contact with insert 151. When the squeeze air pressure is supplied through port 179, the table will be elevated and as the pressure increases to a certain preset value the ram extension 144 will be elevated to the extent permitted by the lip 146. This will cause the insert [51 to engage the underside of the table and continued jolting during elevation or squeeze is accomplished on the center insert with the ram rebounding due to squeeze air pressure.

It will. of course. be appreciated that the chamber I58 may be pressurized with an imperforate piston [37 and without the extension 144 so that the ram 143 will rebound on a pillow of air within the chamber 158. To control the pressure within chamber 158, a pressure control line may be provided through port 157. Such line may lead to a servo valve which is operative in response to the position of the table 132.

Referring now to the embodiment of FIG. 7, there is illustrated a squeeze head against which the sand filled flask is elevated to ram a foundry mold therein. The squeeze head shown generally at 184 includes a peripheral peen strip 185 and a central pouring basin mold imprinter 186. Both are mounted on plate I87 readily removably secured through brackets 188 to vertically extending plates 189. Such plates extend downwardly from the bottom 190 of cylindrical housing 191, the upper end which is closed by plate 192.

The housing 191 is supported on compression springs 193 supported on washers 195. in turn on nuts 1%. secured to the lower ends of support rods 197. Such rods are secured to fixed head frame 198 and extend through

bushings

199 and 200 in laterally projecting ears on the cylindrical housing 191. The top plate 192 of the housing is provided with a FABREEKA pad 202 adapted to engage the underside of the fixed frame 198. Accordingly, the squeeze head is adapted to move downwardly against the compression of the springs 193. but is limited in its upward movement.

Inside the cylindrical housing 191 is a large volume jolt ram 203 which is mounted for vertical reciprocation in the housing. The ram is provided with a cavity 204 in which is positioned a large volume elastomeric urethane insert 205 having a projection 206 thereon adapted to engage projection 207 on the squeeze head bottom plate 190.

To obtain a jolting action, air is supplied through the port 208 to the chamber beneath the ram 203 elevating the same until exhaust ports 209 are uncovered directly exhausting the air beneath the ram. The chamber above the ram may be vented to atmosphere through ports 2l0. The ram. of course. traps air above the exhaust ports to assist in rebounding the ram against the squeeze head.

In the illustrated embodiment. there may be 12 exhaust ports 209. some being fitted with muffler screens indicated at 21 I. while others may be titted with the cylindrical baffle-type mufflers seen at 212. In any evenL the combination of the large number of exhaust ports. together with the mufflers. reduces the exhaust air noise to a satisfactory level while the large volume ram insert 295 reduces the metal to metal impact noise nor mally present.

FIG. 8 is an embodiment of the invention fairly similar to that of FIGv 6. but utilizing the center strike ofthe table and jolt ram for both anvil jolt and shockless jolt during the squeeye. The machine includes base 215 liming upstanding cylindrical housing 216 in which squeeze piston 217 is mounted for vertical reciprocation. The squee/e piston includes an upstanding cylindrical portion 218. the top of which terminates in flange 219 which bottoms on the top of the housing The squeeze piston includes a liner 221 in which the ex tension 222 oftl'ic table 223 Is mounted. Jolt guide pins 224 extend from the table into the liner.

A poppet valve assembly 225 admits air to chamber 226 above jolt ram 227 inside the table extension 222. The jolt ram includes as a separate item extension 228 extending through sleeved aperture 229 in the removable bottom plate 230 ofthe piston 217. The extension includes a lip 23! precluding the same from popping through the sleeved aperture 229. The extension is sup orted on large annular spring plate 232 in the down position ofthe table. the latter being supported on elastomcric ring 233 which may be urethane of a suitable hardness. l'hc plate is held in centered position by a guide pin 234, the head of which precludes the plate from bouncing upwardly excessively or being lifted by squeeze air pressure. The plate is not otherwise held within the machine. The extension 228 is provided with a suitable aperture 236 to provide a suitable clearance between the extension and the guide pin head.

in the down position of the table. the table is so; ported on the insert 237 secured in the jolt ram 227 by the retaining ring 238. When air is admitted through the poppet valve assembly 225 to the chamber 226 above the jolt ram 227, the table elevates until the exhaust ports 240 are exposed to the chamber. where-- upon the table drops providing an anvil jolt impact on the top of the insert 237. The impact is transmitted through the jolt ram to the ram extension 228 and through the large diameter spring plate 252 and the rin 233 to the housing or base 2l5. The large diameter spring plate. which may be 1090 steel. heat treated. thus absorbs. transfers and distributes the relatively concentrated impact as a smaller load to a much larger area permitting the base to take the repeated impact load During squeeze. the squeeze piston 217 elevates to pick up the table at the flange clearance 241. Air pres sure beneath the piston also elevates the extension 22% and the jolt ram 227. Jolt during squeeze is obtained in the same manner as in the FIG ti embodiment.

Again as in the llti. h embodiment. there may be six such exhaust ports 240, each provided with a mulflcr screen 24*. The exhaust ports lead to vertical grooves 243 in the table extension and the port to atmosphere. as indicated at 244. It will of course be understood that the same exhaust system as provided in FIG. (1 may be used in the H0. 8 embodiment with the screened exhaust pvrts being in the liner from an exhaust system Iii F ll

also communicating with the

chambers

245 and 246 the latter in this embodiment being normally vented through the passages 24']. In any event. the urethane insert 237 may be the same as the insert 15! in the FIG. embodiment. and with such large volume insert together with the exhaust system. machines are provided which produce excellent foundry molds at much reduced noise levels.

What is claimed is:

I. In a foundry jolt molding machine having a table adapted to support a sand-tilled lTasl-t. a pneumatically operated jolt mechanism in said table including a verti cally movable jolt ram. the improvement comprising exhaust system porting means for said 5 ilt mechanism progressively enlarging in crust-sectional area towards a plurality of exhaust ports at atmosphere thereby substantially reducing the noise level of the machine. and an expansion chamber in said system between said jolt mechanism and said exhaust ports operative to reduce the pressure of the exhausting air. said expansion chamber being formed in part by a portion of the un dersidc of said jolt ram.

2. A machine as set forth in claim 1 including sound absorbing screens on each of the exhaust ports of such system.

3. A machine as set forth in claim I including piston and cylinder means operative vertically to elevate said table. and a further expansion chamber in such system provided extcriorly of the cylinder of said piston.

4. A machine as set forth in claim 3 wherein said further expansion chamber includes two relatively large laterally extending final exhaust ports.

5. A machine as set. forth in claim 3 including slot means interconnecting said jolt mechanism and such further expansion chamber at all vertical positions of elevation of said table.

6. A machine as set forth in claim I wherein said jolt mechanism includes a cylindrical extension on said table and said jolt ram reciprocally mounted therein. and poppet valve means operative to open by contact between said ram and table. the movement of said poppct valve means being limited to reduce the volume of air required for said jolt mechanism.

7. A machine as set forth in claim I wherein the en largemcnt in cross-sectional area towards the atmosphere is approximately in a ratio of 3 to I.

St In foundry jolt molding machine. having a verti cally movable table. means to elevate said table and then drop the same to obtain a jolt strike. the improvement comprising an elastorneric sound attenuating in-- sert means against which said table is dro ed. the hardness of said insert means being inversely reiated to the area of the strike thereagainst.

9. A machine as set forth in claim 8 wherein said inscrt means includes a heat absorbing and transmitting tiller material.

It]. A machine as set forth in claim 8 wherein said elastomeric sound attenuating insert means includes an annular ring having a large impact area. said ring being relatively soft.

II. A machine as set forth in claim I" wherein said ring has a durometer hardness on the Shore A scale of approximately 60 to about 95.

12. A machine as set forth in claim 8 wherein the said elastomeric sound attenuating insert means including an insert in the center of the table and has a relatively small strike area. said insert being relatively hard.

13. A machine as set forth in claim 12 wherein said insert has a durometer hardness on the Shore D scale of approximately 70.

14. A machine as set forth in claim 3 wherein said insert means includes an insert of solid polyurethane of substantial volume.

15. A machine as set forth in claim 8 wherein said insert means includes an insert of solid polyurethane of substantial volume. and means operative to cool said insert by the passage of machine exhaust air thcreadjacent.

16. A machine as set forth in claim 8 including a reciprocable jolt ram in the center of the table. said insert means including an insert mounted in the end of said ram facing said table and projecting from said ram to receive the table strike thereagainst.

17. A machine as set forth in claim 16 wherein said insert is a large volume of solid polyurethane held in place by a retaining ring.

18. A machine as set forth in claim 8 including air passages extending through a part of said insert means for cooling the same.

19. In a foundry jolt molding machine comprising a table and jolt ram mounted for relative movement to obtain jolt impact. the improvement comprising a large volume elastomeric insert in said jolt ram to receive the impact. whereby such machine will operate to produce high quality foundry molds at reduced noise levels. said table and jolt ram being air operated to obtain such jolt impact. and means to pass such air adjacent such insert to prevent overheating the same.

20. A machine as set forth in claim 19 wherein said insert is solid polyurethane having a hardness of approximately 60 to 75 on the Shore D scale.

2|. A foundry jolt molding machine comprising a table and a jolt ram mounted in said table for relative movement, means to pressurize the end of the ram facing the table relatively to move said ram and said table. means to vent the pressurized end of said ram through a plurality of exhaust ports to bring the table and ram together for ajolt impact. such ram having a large volume elastomeric insert therein to receive the jolt impact. whereby such machine will operate to produce high quality foundry molds at a noise level of less than 90 dbA (A scale). said chamber formed by the end of the ram facing the table and including a plurality of passages adjacent the insert to facilitate the dissipation of heat therefrom.

22. A machine as set forth in claim 21 wherein said insert is solid polyurethane having a hardness of approximately on the Shore D scale.

23. In a foundry jolt molding machine. having a vertically movable table. means to elevate said table and then drop the same to obtain a jolt strike. the improvement comprising an elastomeric sound attenuating insert means against which said table is dropped. the hardness of said means insert being inversely related to the area of the strike thereagainst. said elastomeric sound attenuating insert means including an annular ring having a large impact area. said ring being relatively soft. and exhaust air ports extending through said annular ring.

24. A machine as set forth in claim 23 including muffler screens in said exhaust air ports.

25. in a foundry jolt molding machine comprising a table and jolt ram mounted for relative movement to obtain jolt impact. the improvement comprising a large volume elastomerie insert in said jolt ram to receive the impact. whereby such machine will operate to produce high quality foundry molds at reduced noise levels. and an exhaust system porting means for said table and jolt ram progressively enlarging in cross-sectional area towards atmosphere thereby substantially reducing the noise level of the machine.

26. A machine as set forth in claim 25 including an expansion chamber in such exhaust system to reduce the air pressure of the exhaust.

Claims

1. In a foundry jolt molding machine having a table adapted to support a sand-filled flask, a pneumatically operated jolt mechanism in said table including a vertically movable jolt ram, the improvement comprising exhaust system porting means for said jolt mechanism progressively enlarging in cross-sectional area towards a plurality of exhaust ports at atmosphere thereby substantially reducing the noise level of the machine, and an expansion chamber in said system between said jolt mechanism and said exhaust ports operative to reduce the pressure of the exhausting air, said expansion chamber being formed in part by a portion of the underside of said jolt ram.

3. A machine as set forth in claim 1 including piston and cylinder means operative vertically to elevate said table, and a further expansion chamber in such system provided exteriorly of the cylinder of said piston.

5. A machine as set forth in claim 3 including slot means interconnecting said jolt mechanism and such further expansion chamber at all vertical positions of elevation of said table.

6. A machine as set forth in claim 1 wherein said jolt mechanism includes a cylindrical extension on said table and said jolt ram reciprocally mounted therein, and poppet valve means operative to open by contact between said ram and table, the movement of said poppet valve means being limited to reduce the volume of air required for said jolt mechanism.

7. A machine as set forth in claim 1 wherein the enlargement in cross-sectional area towards the atmosphere is approximately in a ratio of 3 to 1.

8. In foundry jolt molding machine, having a vertically movable table, means to elevate said table and then drop the same to obtain a jolt strike, the improvement comprising an elastomeric sound attenuating insert means against which said table is dropped, the hardness of said insert means being inversely related to the area of the strike thereagainst.

9. A machine as set forth in claim 8 wherein said insert means includes a heat absorbing and transmitting filler material.

10. A machine as set forth in claim 8 wherein said elastomeric sound attenuating insert means includes an annular ring having a large impact area, said ring being relatively soft.

11. A machine as set forth in claim 10 wherein said ring has a durometer hardness on the Shore A scale of approximately 60 to about 95.

12. A machine as set forth in claim 8 wherein the said elastomeric sound attenuating insert means including an insert in the center of the table and has a relatively small strike area, said insert being relatively hard.

14. A machine as set forth in claim 8 wherein said insert means includes an insert of solid polyurethane of substantial volumE.

15. A machine as set forth in claim 8 wherein said insert means includes an insert of solid polyurethane of substantial volume, and means operative to cool said insert by the passage of machine exhaust air thereadjacent.

16. A machine as set forth in claim 8 including a reciprocable jolt ram in the center of the table, said insert means including an insert mounted in the end of said ram facing said table and projecting from said ram to receive the table strike thereagainst.

19. In a foundry jolt molding machine comprising a table and jolt ram mounted for relative movement to obtain jolt impact, the improvement comprising a large volume elastomeric insert in said jolt ram to receive the impact, whereby such machine will operate to produce high quality foundry molds at reduced noise levels, said table and jolt ram being air operated to obtain such jolt impact, and means to pass such air adjacent such insert to prevent overheating the same.

21. A foundry jolt molding machine comprising a table and a jolt ram mounted in said table for relative movement, means to pressurize the end of the ram facing the table relatively to move said ram and said table, means to vent the pressurized end of said ram through a plurality of exhaust ports to bring the table and ram together for a jolt impact, such ram having a large volume elastomeric insert therein to receive the jolt impact, whereby such machine will operate to produce high quality foundry molds at a noise level of less than 90 dbA (A scale), said chamber formed by the end of the ram facing the table and including a plurality of passages adjacent the insert to facilitate the dissipation of heat therefrom.

22. A machine as set forth in claim 21 wherein said insert is solid polyurethane having a hardness of approximately 70 on the Shore D scale.

23. In a foundry jolt molding machine, having a vertically movable table, means to elevate said table and then drop the same to obtain a jolt strike, the improvement comprising an elastomeric sound attenuating insert means against which said table is dropped, the hardness of said means insert being inversely related to the area of the strike thereagainst, said elastomeric sound attenuating insert means including an annular ring having a large impact area, said ring being relatively soft, and exhaust air ports extending through said annular ring.

25. In a foundry jolt molding machine comprising a table and jolt ram mounted for relative movement to obtain jolt impact, the improvement comprising a large volume elastomeric insert in said jolt ram to receive the impact, whereby such machine will operate to produce high quality foundry molds at reduced noise levels, and an exhaust system porting means for said table and jolt ram progressively enlarging in cross-sectional area towards atmosphere thereby substantially reducing the noise level of the machine.