US2341012A - Concrete block machine - Google Patents

Description

1944- H. BQILLMAN ETAL 2,341,012

CONCRETE BLOCK MACHINE Filed Jan. 9, 1942 10 SheetsSheet 1 -IE-l- HENRY z. BlLfMAJV' CHARLES E. ELAEE'E'N FRANK X. MUENZEH m w k Feb. 8, 1944.

H. E. BILLMAN ETAL CONCRETE BLOCK MACHINE Filed Jan. 9, 1942 10 Sheets-Sheet 2 HENHKE'. BJLLMAN CHARLES E FLAS'SEN THANK X MUENZEH 1944- v H.IE. B lLLMAN ETAL Q 2,341,012

' CONCRETE BLOCK MACHINE Filed Jan. 9, 1942 10 Sheets-Sheet s" INVENTORS HEN P? .E. BJLLMAN E'HARLZS E. FLA SEEN BY FHANK XMUENZEH Feb, 8, 1944. H, E BILLMAN ETA 2,341,012

CONCRETE BLOCK MACHINE Filed Jan. 9, 1942 10 Sheets-Sheet 4 Q Q\ Q m E INVENTORJ' H ENE? 15. Elli/MAN CHARLES .E ELASEEN E BY PHANKX. MUBNZE'E Q} N v TTORNEYS.

H. E. BILLMAN EI'AL 2,341,012

CONCRETE BLOCK MACHINE Filed Jan. 9, 1942 10 Sheets-Sheet 5 m-sm5 5 INVENTORS E. BILLMAN UHAHLES .5! ELA 5' SEN BY FRANK x ML/ENZEH W%MTTORNEYS.

Feb. 8,' 1944. H. E. BILLMAN ETAL 2,341,012 CONCRETE BLOCK MACHINE Filed Jan. 9, 1942 10 Sheets-Sheet e 54 w y W z z F )I a I r\I [N VENTORS BZNHYE'. BILLMAN BY CHAHLEB. 5. GLASSEN FRANK X. MUENZEH A TTORNE m Filed Jan. 9, 1942 l0 Sheets-Sheet 7 lTm-lz- INVENTORS I HENRY E. .BJLLMAN CHARLES .E'. ELASSE'N FRANK X. MUENZE'H MW A TT y 1944. H. E. BILLMAN ETAL CONCRETE BLOCK MACHINE Filed Ja.n. 9, 1942 TIE-l5- 10 Sheets-Sheet 8 ampa:- ylinder- QZ'IIGIII) J E J MNmm m HAHN N E A M V L T NEFM T A g HEM m HEP Feb. 8, 1944.

H. E. BILLMAN ETAL CONCRETE BLOCK MACHINE Filed Jan. 9, 1942 TIE-l5 1O Sheets-Sheet 9 ullea 'Vibra 21:-

HENRY .E'. .EJLLMAN CHARLES E E'LASSEN FRANK XMUENZEZ? 1944- H. E. BILLMAN ETAL 2,341,012

CONCRETE BLOCK MACHINE -Filed Jan. 9, 1942 10 Sheets-Sheet l0 HENRY .E'. BILLMAN CHARLES .E. ELASSEN FFANK' X MUE'NZEE Patented Feb. 8, 1944 CONCRETE BLOCK MACHINE Henry E. Billman and Charles E. Glassen, St.

Louis, Mo.,

and Frank X. Muenzer, Elmore,

Ohio, assignors to The Multiplex Concrete Machinery Company, Elmore, Ohio, a corporation of Ohio Application January 9, 1942, Serial No. 426,102

26 Claims.

This invention relates to concrete block making machines, and has for its primary object the provision of certain novel features in such a machine wherein the movement of the parts, with the possible exception of the vibrating action, is pneumatically efiected thereby, lessening liability of breakage should movement of any part be prevented or resisted to a considerable extent for any cause and to enhance the practicability and commercial value of the machine.

Another object of the invention is the provision of means whereby, during pressing, molded blocks maybe maintained in proper size irrespective of the amount of pressure applied.

Another object of the invention is the provision of means for vibrating the mold box during block molding operations and to so mount the mold box that all jar or vibration is eliminated from the balance of the machine structure during vibration of the box.

Another object of the invention is the provision of novel and improved vibrating means for the mold box and block material therein.

Another object of the invention is the provision of novel means and method for effecting dual vibrating of the block material during molding, so that the moisture is substantially uniformly distributed through the block from top to bottom, resulting in a block of substantially uniform density and texture, and the top surface of a formed block is left smooth after pressing.

Another object of the invention is the provision, in combination with means for moving the mold box successively to filling and pressing positions, of means for vibrating the mold box in both positions.

Another object of the invention is the utilization of pneumatic pressures for the tamping andpressing operations and the controlling of such pressures to obtain a block of desired density or porosity.

Another object of the invention is the provision of means preferably of a pneumatic nature in combination with movable supply hopper and mold box units to relatively move said units into superimposed relation for the mold box filling and tamping operations and then to move the filling box to material filling position and the mold box with its tamped material to pressing position.

Another object of the invention is the provision, in connection with the tamping operation, of pneumatic means for regulating the tamping pressure applied to the material in the mold box whereby the density of the tamped material is controlled.

- sion, in connection with the tamping operation,

of means for regulating and determining the number of blows to be delivered during the tamping of each block, thereby suiting the tamping action to the densities desired and the type of material used.

Another object of the invention is the provision in a machine of the class described of mold box filling, tamping, agitating, pressing and vibrating means so combined and coordinated that should various of these means become inoperative v the compression of the others may be continued. For instance the tamping means can be operated with or without the vibrating means and without operation of the pressing means, or the pressing means can be operated with or without the vibrating means and without the tamping means.

Other objects and advantages of the invention will be apparent from the following detailed description, and from the accompanying drawings illustrating the invention, in which- I Figure 1 is a side elevation of the machine, with the parts in normal at-rest position preparatory to starting a cycle of operations, and with parts broken away; Fig. 2 is a central longitudinal vertical section thereof, with parts broken away and parts in full; Fig. 3 is a central vertical longitudinal section, with parts in full, and with the mold carriage and charge box in tamping position, and a previously formed block in section on the take-off carriage; Fig. 4 is a horizontal section of the machine on the line 4-4 in Fig. 2, with the presser head raised; Fig. 5 is a vertical section through the machine on the line 55 in Fig. 4, with the presser head raised; Fig. 6 is a similar section of one side portion of the machine, with the block ejecting means in raised position; Fig. 7 is a fragmentary sectional detail similar to that of Fig. 5, with the ejector means raised to block lifting position and with parts in full; Fig. 8 is a fragmentary side detail view of the parts shown in Fig. 7. with the ejector means in raised position; Fig. 9 is a plan vieu of one end portion of the mold box and its mounting means; Fig. 10 is a section on the line Ill-Ii) in Fig. 9; Fig. 11 is a diaglam of the pneumatic operating means and control for the transfer movements of the charge box. with the parts in cycle ending position; Fig. 12 1s a diagram of the pneumatic operating means and control for the pressing cylinder, with the parts in positions they assume immediately be fore a pressing operation; Fig. 13 is a diagram of the pneumatic operating means and control for the tamping means, with the parts in the position they assume'immediately before a tamping operation; Fig. 14 is an elevation of the tamping means, with parts broken away, and with the pneumatic pressure gauge means in connection therewith; Fig. is a wiring diagram for the vibrator motors; Fig. 16 is a fragmentary front end elevation of the machine equipped with automatic means for operating the take-off carriage, and Fig. 1'7 is a fragmentary side elevation of the front end portion of the machine showing such equipment and with parts shown in diagram.

Referring to the drawings, the frame in its illustrated embodiment includes a base structure composed of cross members I and longitudinally extending connecting members 2, rising from which at the rear are a pair of opposed short side uprights 3, and forwardly thereof at spaced intervals are pairs of opposing tallside uprights 4, 5 and 6. The uprights 4, B and 8 at their upper portions are connected together in pairs and longitudinally of the frame by suitable bars l to cooperate therewith to form a well or space A in which the tamping means is disposed and operates and a well or space B in which the pressing means is disposed and operates. A crossbar 8 (Fig. 5) rigidly connects the lower end portions of the two uprights 5, 5. Longitudinally extending bars 9 are rigidly secured in transversely spaced relation within the frame, one adjacent to each side thereof, and, in the present instance, are attached, as by welding, to bosses l0 projecting from the inner side of each frame upright, as best shown in Fig. 5. The bars 9 extend over the cross-bar 8.

A U-bar I l is mounted on each bar 3 lengthwise thereof by a plurality of adjustable supports l2 and forms a track bar in which are mounted a series of transversely spaced rollers IS with their top peripheral surfaces exposed thereabove. A mold carriage is mounted for reciprocatory movements lengthwise of the frame over the track bars H and includes at each side thereof a runner bar H of channel form, which is guided for movements lengthwise of the frame by the respective track bar i i and rides on the rollers l3 of the associated series. Each bar I! is faced on its top with a runner plate IS, the outer edge of which is projected beyond the bar If to form a side flange thereon. A mold box I6 is mounted at each side thereof on the forward end portion of the respective runner plate l5, as hereinafter described, and is adapted to receive and hold a mold ll of any suitable form, depending on the shape, size and number of blocks or other articles to be molded. The construction and form of the mold I! and its manner of mounting in the mold box IE are immaterial so far as the present invention is concerned, and need not, therefore, be described.

The mold carriage at the rear of the mold box It includes side upright members l8 which are mounted on and rise from the rearward end portions of the runner plates 15 and are connected at their upper edges by a strike-off plate l9, which has its forward edge terminating adjacent to the upper rear edge of the mold and has its top surface in the horizontal plane of the top surface of the mold, as shown in Fig. 3. The plate 19 is of suflicient length to extend rearwardly across and slightly beyond the well A when the mold is in register with the well B in pressing position, as shown inFig. 2.

A material charge box 23, open at top and bottom, is mounted for reciprocatory movements lengthwise of the machine over the plate It and mold l! with the plate l9 forming a bottom closure plate for the box when the latter is thereover. In the operation of the machine the charge box is filled when the parts are in the position shown in Fig. 2, with the plate I9 under the box and with the mold I! at the extreme forward end of its movement in pressing position.. When the mold is moved to tamping position in the bottom of the well A, the box 23 at the same time is moved into superimposed relation to the mold so that the mold cavities may be filled by material contained in the box and the tamping action take place through the box, as shown in Fig. 3.

The charge box 23 is supported for its transfer movements by a set of rollers 24 at each side thereof, bearing upward against horizontally disposed side flanges 25 on the box, as best shown in Fig. 5. These rollers operate in guide grooves onthe under sides of said flanges and are supported by stub shafts 28 projecting inward from horizontally disposed bars 21 secured to the inner sides of the uprights 3 and 4 -(Figs. 1, 2, 3, 4 and 5).

A material supply hopper 30 is disposed in the rear portion of the frame between the uprights 4 and is positioned to have its bottom open to the top of the charge box 23, so as to deliver material thereto, when the charge box is at the rear end of its stroke in material receiving position, as shown in Fig. 2. The charge box has a rearward extension 3| which moves under and completely closes the bottom discharge opening of the hopper when the box is in mold charging position. The hopper is preferably provided at its rear side near its bottom with a secondary opening 32 (Fig. 2), which may be used either to supply material to the bottom portion of the hopper or for the insertion of a tool for agitating the material to the hopper.

A common means, preferably having a pneumatic power source, is employed to operate the mold carriage and charge box in proper relation and will now be described. In the present instance, the various pneumatically operated parts of the machine are adapted to be operated by air pressure, and reference will therefore be made to "air in the subsequent description of the machine operation. It will be understood, however, that a fluid pressure medium other than air may be employed if desired.

An air cylinder 35 is suitably mounted at the rear end of the machine below the plane of movement of the strike-off plate [9 on suitable cross members 36 mounted on and connecting the track bars 9 and substantially aligned horizontally with the mold box IS. A piston 31 operates in the cylinder and has a rod 38 projecting therefrom through the forward end of the cylinder and connected to a cross-bar 20 between the carriage uprights l8, as best shown in Figs. 2 and 3, so that reciprocation of the piston 31 within the cylinder will impart requisite movement to the mold carriage. The control for the admission of air under pressure to first one end and then the other of the cylinder 35, at opposite sides of the piston, will be hereinafter described.

Disposed in the rear end at each side of the path box 23 and strike-off plate chain 40 guided by a pair portion of the frame of travelof the charge I9 is an endless power of sprocket-wheels 4| which the cylinders project.

which are spaced loniitudinally of the frame to provide a lower run a. and an upper run I: for the chain. When the mold l1 and charge box 23 are in the separated positions shown in Fig. 2, the lower run a oieach chain is attached near its forward end at c to the rear end portion of the respective side member l8 of the mold carriage, while the upper run b is attached near its rear end, as at d, to the rearward extension 3! of the charge box 23. It is thus apparent that movement of the mold carriage in one direction will communicate movement through the chains 40 in the opposite direction to the charge box, so that a rearward movement of the mold box to tamping position will cause forward movement of the charge box into verticalregister with the mold box in such position, and a return of the mold box to pressing position will cause a return of the charge box to material supplying register with the supply hopper.

In order to prevent a lifting of the mold carriage from the track rollers l3 during an operation of the machine, and particularly during an operation of the block ejecting means, as herein after described, each runner plate I is .engaged over its projecting side edge near the rear end thereof when in pressing and ejecting position by a guide finger 42 (Fig. 5) and is engaged at its forward end when in such position by fingers 43 (Fig. 2).

Tamping means The tamping means is disposedin the well A of the frame and includes a vertical air cylinder 45 in which a piston 46 operates. The piston rod 41 projects down through the'bottom of the cylinder and carries a manifold head 48 from which a colony of air compression cylinders 49 downwardly project and are tied together at their lower ends by a perforated plate 50 through These cylinders, in the present instance, are twelve in number and are arranged in three longitudinally extending rows of four cylinders each. Each cylinder 49 contains a piston 5| downwardly from which a piston rod 52 projects through the bottom of the cylinder and carries at its lower end a tamping element 53. The number and arrangement of the tamping elements, and accordingly the cylinders '49, are best shown in Fig. 4. This number and arrangement will, of course, vary in accordance with the shape and size and number of cavities in the mold. In the present instance, the mold, as shown in Fig. 4, is divided into three sections for forming three separate blocks and each section has three core members 54 therein. The tamping elements are intended to enter a mold cavity of each section at each end without the respective end core members 54 and also to enter the spaces between succeeds ing core members, thus requiring four tamping elements for each mold section in order to secure satisfactory tamping. Each tamping element, in the present instance, is of I-form in crosssection. It will, of course, be understood that the form and number of the tamping elements may be changed to suit the cavity formation of a mold section.

The air in each cylinder 49 is intended to serve as a cushion for the respective tamping element and is regulatable as to pressure to suit the pressure desired to be exerted by the tamping ele-' ment on the material during a tamping action. The several cylinders 49 at their upper ends have connection through manifold passages in the l'ill head 48 with a pipe 55 which extends up at a side of the power cylinder 45 and connect: at its upper end through a connection 54 with I. controllable pressure source. The pipe ll has its upper end attached to the cylinder 45 and is of telescoping form to maintain the air connection durlng'reciprocatory movements of the head 48. It is apparent that the tamping action of the several tamping elements on the material is cushioned by the air pressure back of the pistons 5|, and that while such pressure is suiilcient to force the elements down through the loose material during the initial part of the tamping action, the pistons 5| will rise in the cylinders during successive tamping strokes and as the material in the mold box becomes more and more compressed from the bottom upward. Also, if an unusual obstruction is encountered by any tamping element during a tamping action, the air cushion back of the element will yield to prevent any breakage. The pistons and attached elements may assume different vertical positions when the tam-pin colony is at the limit of its down stroke, as shown in Fig. 3, due to a difference in density of the material at various points in a mold.

For the purpose of regulating the air pressure in the cylinders 49, the pipe 56 is adapted to have connection with a pressure tank 51 (Fig. 14), the supply line of which is provided with a pressure regulating valve 58. In-this manner the blows delivered by the tamping elements may be regulated to suit the tamping pressure desired.

Pressing and sizing means When a mold with tamped material therein has been transferred to pressing position at the bottom of the well B, as shown in Fig. 2, the material is subjected to a predetermined pressure to impart the desired density thereto and to give the formed blocks the desired sizes. For this purpose, an air cylinder 60 is mounted in the upper end of the well B and has a piston 6| therein connected by a rod 62 to a presser head 63 below the cylinder. This presser head is in the form of a hollow cross-beam having a chamber 64 therein, and is provided at its under side with a series of presser plates 65 corresponding to the number of sections in the mold l9 and each fashioned to fit in the upper portion of the cavity of the respective section, whereby pressure applied to the plates is uniformly distributed downwardly on the top of the material in the mold when the presser head is substantially at the limit of its down stroke, as shown in Fig. 2. The means for controlling the admission of air to one or the other end of the cylinder 60, to effect a raising or lowerin of the presser head, is automatic and will be later described.

The presser head 63, at each end thereof, is provided with a guide block 66 which projects into the space between the frame uprights 5 and 6 at the same side therewith and cooperates with guide strips 61 secured to said uprights (Figs. 1 and 5) to guide the reciprocatory movements of said head.

Block ejecting means means includes a cross-head l0 mounted in the lower portion of the well B below the mold pressing position which carries a plurality of ejector fingers II that enter registering openings in the bottom plate of the mold II and during an upward movement of said cross-head engage pallets 13 in the bottom of the mold sections and force them upward with the molded blocks to takeofl'" position (Fig. 7).

The cross-head I has its ends projected into the adjacent spaces between the respective sets of frame uprights and 6 and cooperate with suitable guides I4 attached to said uprights (Figs. 1 and 4) to guide the vertical reciprocatory movements of the head. A bracket I5 projects upward from each end of the head within the space between the adjacent set of uprights 5 and 8 and has a pivot stud I6 projecting outward therefrom (Fig. 5). A vertically movable trip-bar II is disposed at each side of the frame without the guiding means for the head I0 and has its lower end provided with a vertical slot I8 receiving the adjacent stud I6. The upper end of the trip-bar I1 projects up through a guide opening in the respective guide block 68 and has a vertically elongated opening 19 therein which straddles a pin 80 which attaches the guide block to the crosshead 63. The outer side of the bar 11 adjacent to the lower end of the opening "I8 is provided with a cross notch 8| which, when the presser head 64 has lowered substantially to the limit of its pressing stroke, registers with and is lockingly engaged by a cam shaft 82, as shown in Fig. 6. This shaft is mounted in the guide block 66 crosswise thereof at its outer end and has one side cut away to have flat engagement with the outer side of the trip-bar to permit relative reciprocatory movements of the bar and presser head, except when the presser head has been lowered to place the shaft 82 in register with the notch 8|, which permits a turning of the shaft into locking engagement with the upper end wall of the notch to cause the trip-bar to be moved upward with the presser head when raised. The shaft 82 has an arm 83 projecting from one end thereof and connected by a coiled contractile spring 84 to a fixed part 85 on the guide block 66 to urge the shaft to normally turn into locking engagement with the trip-bar.

To each end of the cross-head I0 is fulcrumed a lever 88, which is substantially horizontal and has the free ,end of its short arm (Figs. 1 and 4) tripping, is provided at one end with an arm 93 carrying a roller 94 with which the cam portion 95 of a. trip-bar 86 is intended to engage to effect a release of the lock shaft from the respective trip-bar II when the trip-bar 96 has been lowered a predetermined extent from the raised position in which it is normally held by the spring 9! (Figs. land 7). Each trip-bar 86 is connected by a respective link 98 (Figs. 1 and 4) and rocker arm 99 to a rock-shaft I00 mounted at the front end of the machine crosswise thereof- Bar tripping movements may be imparted to the shaft I00 by a manually operable lever IN, or the shaft may be automatically operated as hereinafter described in connection with the automatic block take-off means.

In order to prevent a sudden dropping of the ejecting means when the trip-bars II are released by the lock shafts 82, each trip-bar II has a rod I02 projecting upward therefrom and provided at its upper end with a plunger I03 operating in a dash pot I04 which is suitably supported at the upper end of the frame, as best shown in Fig. 5. The dash pot contains oil and this passes slowly through perforations in the plunger to cause a slow lowering of the ejector mechanism in a well known manner.

Block ftake-ofi means Fixed at its rear end to and projecting forward from each frame upright 6 (Figs. 3 and 4) is a horizontally disposed frame I05 supported at its outer end at each side by a brace I08 rise ing from the bas portion of the frame. A horizontally disposed track-bar I0! is mounted at its forward end to the forward end of the frame I05 for vertical rocking movements, and in the a present instance is of channel bar formation positioned to bear downward on a frame block 89,

so that an upward movement of the opposite arm of the lever 'will impart an initial forceful raising movement to the cross-head I0. The outer end of the long arm of the lever 88 is connected by a link 90 to the adjacent trip-bar II a distance above its slot 78, so that during an upward lost motion movement of the trip-bar 11 relative to the pin I6 the lever will operate to effect a start ing movement of the cross-head. During the continued upward movement of the two trip-bars II with the presser head, the cross-head I0 is raised with its channel facing inward. The rear end portion of each track-bar is supported by a leg I08 carrying a roller I09 at its lower end which rests on a'cam IIO on the rock shaft I00. A movement of the shaft I00 to tripping position for the trip bars 96 causes th high portion of the cams IIO to turn under the rollers I09 and effect a slight raising of the rear end of the track bars I0'I for the purpose hereinafter described.

A take-off carriage III is mounted for horizontal reciprocatory movements on the trackbars I01 and has a body part I I2 provided with rollers which travel in the channels of the respective track-bars I0'I. Mounted on and projecting rearward from this body part are a plurality of fingers II3 which, upon a rearward movement of the carriage, may be projected under the pallets I3 of the molded blocks which have been raised to take-off. position by the ejecting means. The carriage, of course, is moved under the blocks before a tripping and lowering ofthe ejecting means with the cams IIO on the manual control shaft I00 in lowered position, thus permitting'the forward end of the carriage fingers to pass under the raised blocks and their supporting pallets free from engagement therewith, as shown in Fig. 8. The movement of the control shaft I00 to release the ejecting means and permit its lowering causes the cams IIO to be actuated to raise the rear ends of the track-bars I01, and conse quently the carriage fingers, upward sufficiently to engage the under side of the block supporting pallets I3, so that any dropping of the newly molded blocks to engage the take-off carriage. and consequent jar to the blocks, is prevented when the ejecting means is lowered. As previously describedg'the ejecting means immediately drops tondrmal position when the control trip is operated. Either after or during such dropping movement the take-off" carriage HI with the newly molded blocks thereon may be moved out to the carrying-away" position shown in Fig. 3.

This raising of the take-off carriage into supporting engagement with the block carrying pallets after the carriage moves thereunder and before the ejecting means starts its lowering or return movement to normal position is important, as it eliminates the jar and possible injury to the newly molded blocks which has been found in practice to occur when such blocks are lowered into engagement with a take-off" table during a lowering action of the ejecting means.

The take-off carriage III may be manually moved to and from block taking-off position'as indicated by reference to Fig. 3, or it may be automatically effected at predetermined stages in a raising or lowering of the block ejecting means l0, H, as shown in Figs. 16 and 17. For this latter purpose the take-off carriage HI is yieldingly connected by a downwardly and rearwardly projecting bar 250 to a horizontally disposed arm or rod 25f which is parallel with and attached at its forward end to the forward .end of a piston rod 252. The yielding connection of the bar 250 with the rod 25l is through two opposing springs 253 acting outwardly, against nuts or stops 254 on the rod. The piston rod 252 has its piston 254 operating in a long air cylinder 255 projecting forwardly from the rear end of the machine frame. The admission to and exhaust of air from one end or the other of said cylinder is controlled by a four-way valve 256 having an operating rocker arm 25! projecting therefrom and carrying a roller at its free end.

The valve has an air pressure supply line (not shown), and has connection with the forward end of the cylinder through a line 11. and with the rear end of the cylinder through a connection w. The valve arm 25! is normally held by a spring 258 in the lowered position shown; in which position the line w to the rear end of the cylinder is open to the pressure supply line, and the line it to the forward end of the cylinder is closed to the supply line and is open for exhaust. I

When the ejector cross-bar is raised from its lowered position, an arm 259 thereon engages the roller on the valve arm and effects a movement of the valve to reverse the air action, that is, opening the rear end of the cylinder to the exhaust and its forward end to the air pressure supply. This latter control action, however, is not effected until the ejector means is very nearly at the top of its ejecting the rocker arm 28! actuates the cam H0 to raise the carriage fingers I ll up under the elevated blocks into engagement therewith. as hereinbefore described.

When the ejector parts have returned to their normal lowered position by a tripping of the bars 11, as hereinbefore described, the valve arm 251 will be permitted to return to its lowered position under the action of the spring thereby reversing the action of the air in the cylinder 255 and causing the plunger to be returned to its forwardly extended position and to draw the ejector carriage forwardly therewith. As the plunger begins its forward movement, the rod 25f releases the plunger of the air valve 260 and permits such valve to close the communication of the pressure supply line with the cylinder 26L This permits movement of the cams 0 from the track arms 18 and a consequent slight lowering of the rear end of the carriage with the formed v blocks thereon.

stroke, so that the fingers H3 of the take-off carriage may be advanced under the raised blocks.

When the take-off carriage H2 has approximately reached the limit of its rearward stroke, the forward end of the rod 25!, which is tapered or inclined for the purpose, passes under the plunger of a normally closed valve 260 in an air pressure supply line a: and moves the valve to open such line and admit air under pressure to the lower end of an upright cylinder 26l beneath a plunger therein. This plunger has its rod 262 connected by a link with a rocker arm 263 projecting forwardly and downwardly from the cam shaft I00 carrying the cam H0. The raising of Vibrating means Vibration of the block material in the mold is intended to take place during both the tamping and the pressing operations; to be discontinued during a transfer of the mold from tamping position to pressing position, during which transfer the material in the charge box 23 is stripped from the material in the mold', and to be of a dual nature during the pressing operation.

It is found that if the vibration of the mold continues during the retracting movement of the charge box from over the mold, the material in the mold becomes progressively of greater density from front to rear due to the progressively longer period of register of the charge box with the mold during such movement. In other words, more material will be discharged into the. rear end of the mold than into its front end. It is, therefore, desirable to have the vibration action stop substantially simultaneous with the breaking of the motor circuit, which can be accomplished by the type of motor used, as well understood in the art.

It is also found desirable during the pressing operation to effect a dual vibration of the material, whereby it is vibrated both at top and bottom in order to impart a smooth top surface to the material in the mold and eliminate voids therein during a single pressing action. In practice, the block is subjected to a finishing pressure of approximately 2000 pounds, and if vibration does not occur on the top of the material during such pressing action, it is'i'ound that the top surface has many voids therein due to the coarse nature of the material and to the fact that the material cannot properly adjust itself to eliminate the voids during the pressing action. By vibrating the top surface of the material during the pressing action, the material is given a more finished smoothness on top as would otherwise occur only under a longer and greater pressing action or under repeated pressing operations. The vibrating of the top surface of the mold material, therefore, not only produces a smooth top surface, but effects such smoothness in a shorter time and with less pressure than would otherwise be the case.

In order to effect vibration of the mold in both stages of its transfer movements, 9. cross shaft I I5 is mounted in brackets H6 at each end of the box it and an endless chain II! is mounted around sprockets I I8, H8, on said shafts at one end thereof and is thencelooped down between a pair of sheaves I I9 and around a drive shaft I20 relation by suitable bolts.

on a shaft of a drive motor I2I. The shafts IIE are provided with one or more eccentric weights I22 (Fig. 4), which, when rapidly rotated with the shafts, impart violent vibration to the mold box. The sheaves II9 have their shafts stationary with respect to the machine frame, being connected in the present instance to one of the longitudinally extending bars 9, o that the transfer movements of the mold box take place relative to the looped portion of the belt which extends down to the motor, as is apparent by reference to Figs. 2 and 3. The motor I2I, in the present instance, is mounted on a bracket I23 which is pivoted at one end to the base portion of the frame so that its tendency to swing downward under the weight of the motor serves as a simple means for maintaining the vibrator belt taut. It is found desirable in practice to use a chain II'I instead of a belt and to use sprockets II8 on the shafts H in place of sheaves, so as to effect a synchronized running of the weighted shafts and thereby prevent unbalanced action.

To facilitate the vibrating action, the mold box it is provided at each side centrally thereof with a trunnion I25 (Figs. 5, 9 and in the present instance of hexagonal form in cross-section, and each trunnion is mounted in a correspondingly shaped opening of a bearing block I26 with a rubber cushion i2? therebetween, so that the trunnion has a yielding floating support in the bearing, which is mounted on and rises from the runner plate I5. The mold box at each side of the trunnion I and its bearing is provided with alug I28 which rests on and is spaced from the plate I5 by a rubber cushion block I29. A bolt I30 projects up from the plate I5 through the cushion block and lug and holds the parts material, a vibrator motor I (Figs. 3 and 5) is mounted in the chamber 66 of the cross-beam 63 and transfers its vibrations to the presser plates 65 through cushion members. In the present instance, the motor shaft, on which eccentric weights I36 are provided, is mounted at its ends in standards I 31 rising from a base plate I38, and the motor itself is cushioned from this plate by an interposed rubber mat I39. The plate I38 in turn is mounted through intermediate rubber cushions I40 on a plate I, which serves as a closure plate for an opening in the bottom of the beam 63 through which the motor may be inserted, and the presser plates are attached to the under side of the plate I4I through the medium of interposed rubber spacers I42. The several mounting parts are held in assembled It is apparent that vibration set up by rapid rotation of the weights I36 is communicated through cushions to the presser plates 65.

Both motors I2I and I35 preferably should be of the substantially instantaneous stopping or brake type.

Transfer, tamping and pressing controls These various controls are so interconnected and interdependent that they must be considered more or less together.

It will be understood that at the end of each cycle of operations of the machine the parts are in the position shown in Figs. 1 and 2, except in the latter the presser means is raised and the molded, blocks have been ejected. In this position the charge box 23 stands at the right below the hopper 30 from which it is filled and the mold stands at the left in pressing position. In order to start a cycle of operations, the operator presses a starter button I50 located on one of the uprights 6 at the front of the machine, and this effects the opening of an air pressure valve I5I (Fig. 11), which permits air under air line pressure to enter the transfer line I52 from the supply line I53. This supply line includes a valve I54 which is only open when the ejector means, including the trip-bar II, is in its normal lowered inoperative position. For this purpose, one of the trip-rods 11 carries at its upper end a stud I55 which, when the trip-rod is in its completely lowered or at-rest position, engages a lever I56 mounted on the upright 5, and moves it to effect an opening of the valve I54 against the tension of a closing spring, as shown in Fig. 8 and more or less diagrammatically in Fig. 11. It is thus apparent that an operation of the press cannot be started until the ejector means has returned to its'normal inoperative position.

The opening of the starter valve I5I permits air under operating pressure to pass through the line I52 to one end of a cylinder type reverse valve I51 in which a plunger I58 operates. Air pressure from the line I52 causes movement of the valve plunger to the left, cutting off the connection of a supply line I59 to the right end of the transfer cylinder 35 and causing air from such line to enter the left end of the cylinder and permittingexhaust from the opposite end. This causes a movement of the plunger 31 to the right in cylinder 35, which in turn draws the mold box to charging and tamping position in the well A, as shown in Fig. 3. This movement in turn of the mold box and its strike-off plate I9 acts through the chains 40 to move the charge box 23 into superposed charging relation to the mold box and in register with the tamping means.

Just before the mold box has reached its tamping position a pivoted trip finger I60 thereon (Fig. 13) passes over and operates a valve plunger I6I to momentarily open a pilot valve I62 which in turn opens a pilot supply line I63 to and through a trip valve I64, then open, to one end of the cylinder of a reverse valve I 65. The opening of the line I63 moves the plunger of the reverse valve I65 in a direction to permit admission of operating air through the line I66 to the upper end of the power tamping cylinder 45 and permits exhaust from its opposite end. When the tamping colony associated with the cylinder 45 is in its raised position, a projection I61 thereon acts on and holds the valve I64 open. The admission of air pressure to the upper end of the cylinder 45 imparts a down stroke to the tamping colony, thus releasing the trip valve I64 and permitting it to close. When such colony has reached the limit of its down stroke the extension IB'I will have engaged and opened a companion trip valve I68, which opens a pilot supply of air through the line I 69 to the opposite end of the reverse valve I65 and effects a reversal thereof, so that air pressure to the upper end of the cylinder is cut off and air pressure admitted to the lower end through the line I10 from the main power supply line I! I.

In order to prevent stopping of the tamping action when the tamping colony has returned to its raised position and opened the trip valve I64, a repeater control is automatically brought into operation so as to cause the tamping colony to make a predetermined number of strokes before being stopped. For this purpose, at each clown stroke of the tamping colony a roller I15 thereon engages and imparts movement to a lever I16 (Fig. 1), which lever in turn actuates a pawl I'II to move a ratchet wheel I18 the length of one tooth. This wheel is mounted on a cross shaft I19 mounted crosswise in the upper portion of the frame and carries a repeater cam I80 and a safety stop cam I8I (Figs. 11 and 13).

The repeater cam I80 has a number of equidistantly spaced depressions I82 in its periphery, which determine the number of stops of the tamping means in a complete rotation of the ratchet wheel and the spacing between these recesses, considered in connection with the number of teeth in the ratchet disposed in the same length arc, determine the number of repeating strokes of the tamping means for each cycle of operations. For instance, the ratchet has twentyfour teeth and the repeater cam has four notches. There will,' therefore, be six strokes of the tamping colony during each machine cycle or for each tamping operation. The action and purpose of the stop cam I8I will later be described.

Upon the first down stroke of the tamping colony the ratchet I18 will be moved the length of one tooth, which is sufficient to throw the engaging roller of a plunger check valve I83 to open position (Fig. 13), which position is maintained until the next depression of the cam has moved into register with the roller. This valve is disposed in a pilot air pressure supply line I84 which connects with the line I63 and through it to the trip valve I64, so as to suppl air pressure to the line I63 when the pilot valve I62, with which it was initially connected, has closed. This causes air pressure to be supplied to the right hand side of the reverse valve I65 each time the tamping colony returns to its raised position and opens the trip valve I64 so that the tamping strokes are repeated until the cam I80 has turned sufliciently for the roller of the valve I83 to drop into the next cam depression I82. No further tamping will then occur until the next cycle of operations of the machine. The line I84 connects with the line I63 between two oppositely closing check valves I85 therein.

A check valve I90 (Fig. 11) is disposed in an air supply line I9I, which leads through a normally closed check valve I92 to the opposite end of the reverse valve I51 to that to which the initial starting line I52 is connected. When the machine is-at rest between cycles, or when the roller of the check valve I83 (Fig. 13) is in a depression of the cam I80, the roller of the plunger of the valve I60 stands on one of four equidistantly spaced high spots I93 of the stop cam I8I, so that the valve I90 is then in open position. The high spots I93 correspond innu'rn her and spacing to the depression in the cam I80. The cams I80 and I8I move together so that as the plunger of the check valve I83 moves out of register with a depression in the cam I80 and to open position, the plunger of the valve I90 will drop from a raised point so as to close the valve. This closed position of the valve I90 will continue until its plunger moves on to the next high spot, which takes place at the same time the plunger of valve I83 drops into the depression of its cam. It is apparent that the valve I90 serves as a safety stop valve in the reverse supply line I9I to the transfer valve I61 so as to prevent a transfer or the mold box carriage and charge box from tamping position until the tamplng operation is completed. Therefore, upon a completion of a tamping operation, both the safety stop valve I90 and the trip valve I82 are open to permit the passage of air pressure through the transfer line I9I and effect movement of the 12) Passes over the roller of a pilot valve plunger 20I to effect an opening of the air pressure line 202 to the right end, in the present instance, of

a reverse valve 203, which controls the admission and exhaust of air pressure to one end or the other of the pressing cylinder 60. Such admission of air pressure to the valve 203 opens an air pressure supply line 204 to the upper end of the cylinder through the line 205 and closes the supply line communication to the lower end of the cylinder through the line 206. It is thus apparent that by the time the mold carriage has reached pressing position, the pressing means will be energized and the presser head 63 will have started its down or pressure stroke. When the presser head has approximately reached the limit of its down or pressing stroke, a trip pin 20] thereon will have engaged and moved a trip lever 208 mounted on one side of the press frame and eifected a movement of such lever to open a trip valve 209 in a pressure supply line 2I0 to the left end of the reverse valve 203. This efiects a movement of the reverse valve plunger to the right, so as to close the air pressure supp y to the upper end of the cylinder and open the supply to its lower end. It is apparent that there is only one stroke of the pressing means and that pressure will not again be supplied to the upper end of the pressing cylinder until the next block forming operation of the machine. The trip pin 201 is preferably adjustable to vary its point of engagement with the lever 208 to suit the extent of compressing action desired to be applied to the mold material and to determine the sizing of the molded blocks. In this manner, the reverse valve 203 is actuated to stop the pressing action and raise the pressing means when the formed blocks have been given a predetermined depth.

It will be understood that when the mold carriage is at the limit of its rearward stroke, the trip finger I60 will have passed over the valve plunger I6I, and also that when the mold carriage is at the limit of its forward position, the trip finger 200 will have passed over the valve plunger 20I. It is thus apparent that the valve plungers I6I and 20l will be only momentarily opened during respective rearward and forward movements of the mold box and will stand in valve closin position when the mold box is at either limit of its movement.

Vibration control The vibrator motors I2I and I35 are both connected, in the present instance, in a single circuit (Fig. 15) and are controlled by two main switches H and M6 mounted on a side of the frame (Fig. 1) and operated by movements of the mold carriage, an auxiliary switch 2i! operated by movement of the transfer reverse valve I51, and an auxiliary switch 2l8 operated by movement of .the presser means reverse valve 203.

The switch 2l5 is normally open and ls closed by engagement therewith of a flange 2 I 9 on a side of the mold carriage immediately after ,the carriage has started its rearward movement from pressing to tamping position, and is maintained closed thereby until the carriage has returned to near the end of its forward stroke. The switch 2l6 is normally closed and is opened by engagement therewith of a flange 220 on a side of the mold carriage and is held open thereby during the same period of operation that the iswitch 2I5 is held closed. The auxiliary switch 211 is dis- .posed in circuit with the main switch 215, is normally closed, and is opened by the engagement therewith of an extension 22| on the rear or 7 right hand end of the plunger I528 of the trans fer valvel5l. when such plunger. is at the rear end of its movement, or is in position for admitting air to the rear end of the transfer cylinder to move the mold carriage to and hold it in its forward position. The opening of the switch 2" thus occurs at the end of a tamping operation and continues until the commencement of the next cycle of operations. The auxiliary switch 218 is disposed in circuit with the main switch 2l0 and is normally closed. This switch is opened by engagement therewith of an extension 222 on the plunger of the reverse valve 203 for the presser cylinder when the valve plunger is at the end of its stroke, which admits air to the lower end of the press cylinder 60.

As the mold carriage moves rearward upon the starting of a cycle of operations of the machine, the flanges 219 and 220 thereon will respectively act on the main switches H5 and 2 l6 to close the former and open the latter, and such position of these switches is maintained until the carriage has returned to pressing position or to the forward end of its stroke. During the rearward movement of the mold carriage the auxiliary switch 2|! is also closed. The wiring is such that when both of these switches are closed the mold box vibrating motor l2l alone will be operated. During the transfer movements of the mold carriage and until it has returned to pressing position, the presser head vibrator motor I35 is dead, due to the control of such motor being through the switches 2l6 and 218, both of which are open during such transfer movements and 'during which period the presser means is inoperative. At the end of the tamping operation and immediately before the mold carriage starts its forward or return stroke to pressing position, the auxiliary valve 2H is opened by movement of the transfer valve plunger to the right, thereby stopping the operation of the motor l2! and the vibrating of the box. When the mold carriage has substantially reached the limit of its forward movement to pressing position, the flange 220 will have ,moved from engagement with the switch 216 and permitted its closing. This switch is in circuit with both motors. The auxiliary switch 2l8, however, is disposed in series with the switch 2l6, so that the two motors will not be operated to start vibration of both the mold box and presser head until the reverse valve 203 has been moved to admit pressure to the upper end of the presser cylinder 60, at which stage the switch H8 is released by the plunger extension 222 on said valve and permitted to close. Inasmuch as both switches 218 and 2H! are in circuit with both motors i2! and I35, vibration of both the mold box and presser head is effected and continues during the pressing operation and until the valve 203 has been operated, at the lower end of the presser stroke, to effect a raising of the presser head. When this occurs, the switch 2l8 is opened and the operation of both motors is stopped.

We wish it understood that our invention is not limited to any specific construction, arrangement or form of the parts, as it is capable of numerousmodifications and changes without de parting from the spirit of the claims.

Having thus described our invention, what we claim-as new, and desire to secure by United States Letters Patent, is:

v "1. In a machine of the class described having tamping and pressing positions, separate mold and charge boxes movable to superimposed tamping position and respectively from such position to pressing and material supply positions, pneumatic means operable to move one of said boxes to tamping position and then back to its other position, and means connecting said boxes and causing the movement of the other of said boxes to and from tamping position simultaneous with the movement of the pneumatic means operated box respectively to and from tamping position.

2. In a machine of the class described having tamping and pressing positions, a mold box movable from pressing to tamping position and vice projecting therefrom, a charge box movable from material supply to tamping positions, and when in tamping position being disposed in charging position over the mold box, said cut-off plate closing the bottom of the charge box except when the boxes are in tamping position, means operable to impart transfer movements to one of said boxes, andmeans operable to cause transfer movements to be imparted in unison from one box to the other whereby the boxes are simultaneously moved to and from tamping position.

4. In a machine of the class. described having a material supply position and a tamping position, a mold box movable to and from tamping position, means for imparting such movement to the mold box, a charge box movable from material supply position to tamping position over the mold box when in such position, and chain and sprocket means connecting the mold and charge boxes and operable to move the charge box to tamping position when the mold is moved to such position and to move the charge box to supply position when the mold is moved from tamping position.

5. In a machine of the class described, a reciprocally movable tamping head having a tamping element projecting downward therefrom for cushioned tamping movements, fluid pressure means regulable as to pressure for cushioning the tamping movements of said element relative to the head, and means for'imparting reciprocatory movements to said head. I

6. In a machine of the class described, a power cylinder, a plunger operable in said cylinder and carrying a tamping head below the cylinder, a tamping element movable with said head and having cushioned connection therewith to permit a yielding movement of the tamping element relative to the head under predetermined pressure, regulable fluid pressure means for controlling the cushioned movements of the .tamping element relative to the head, and means operable to admitfluid pressure to either end of said cylinder and exhaust from the other to effect first an outward and then an inward stroke of the plunger and head.

7. In a machine of the class described, .a reciprocally movable tamping head having a plurality of tamping elements projecting downward therefrom in th direction of tamping movements. regulable fluid pressure means for cushioning the tamping action of the several elements relative to the head, and means operable to impart reciprocatory tamping movements to the head.

8. In a machine of the class described, a vertically movable tamping head having a plurality of tamping elements projecting downward there- ,from for movements with the head and for movements relative thereto in the plane of the tamping force, regulable fluid pressure means for normally holding said elements extended relative to the head and permitting cushioned inward movements thereof relative to each other and to the head, and means operable to impart downward and upward strokes to the head.

matically operable to cause timed operation of the vibrating means when the mold box has returned to pressing position.

12. In a. machine of the class described having tamping and pressing positions, a mold box movable from pressing to tamping position and vice versa, means operable to vibrate the mold box when in both pressing and tamping positions, means operable to apply pressure to the top of material in the mold when in pressin position,

and means operable to vibrate the pressing means during a pressing action.

1 3. In a machine of the class described having pressing and tamping positions, a mold box movable from one to the other of said positions and vice versa, means operable to impart transfer 9. In a machine of the class described having tarnping and pressing positions, a mold movable from pressing to tamping position and vice versa,

means operable to vibrate the mold when in tamping position and during movement from pressing to tamping position, and means automatically operable to stop the action of said vibrating means immediately after the tamping operation.

10. In a machine or the class described havin tamping and pressing positions, a moldmovable from pressing to tamping positions and vice versa, means for supplying material to the mold when in tamping position, means operable to strike of! said supply trom the mold when the latter is being moved from tamping to pressing positions, means operable to vibrate the molds in both presslngand tamping positions, and means for rendering said vibrating means inoperative during a strike-off movement of the mold.

11. In a machine of the class described having tamping and pressing positions, a mold movable from pressing to tamping position and vice versa and having a material strike-oi! member projecting therefrom, a charge box movable over saidstrike-off member and into superimposed relation to the mold when in tamping, position and vice versa, means for imparting reciprocatory movements to the mold, means for imparting reciprocatory movements to the charge. box, means operable to vibrate the mold box inboth tamping and pressing position, and means automatically operable by predetermined movements of said mold to cause operation of the vibrating means while the mold i in tamping position, means automatically operable to'discontinue the operation of the vibrating means during return of the mold from tamping to pressing positions and during which period the material in the charge box is struck off from the mold, and means automovements to said box from one position to the other and vice versa, means operable to apply a sizing pressure to material in the mold box when in pressing position, separate means operable to vibrate the mold box and pressing means, means automatically operable by the transfer means to cause operation of the box vibrating means while the box i in tamping position and operable to discontinue said vibrating action during movements of the box from tamping to pressing position, means automatically operable to cause operation of both vibrating means when the mold box has returned from tamping to pressing position, and means automatically operable at a predetermined point in the movement of the pressing means to render both vibrating means inoperative.

14. In a machine of the class described wherein a presser head vertically reciprocates over a mold box to press material into" block form therein, an ejector means for the formed blocks including a cross head vertically movable beneath the mold box and having upwardly projecting fingers for moving upward through the mold box to eject the block therefrom when the cross head is raised, vertically reciprocatory trip means having lost motion connection with said cross head, means carried by the presser head for locking engagement with said trip means when the presser head is at the lower end of a pressing stroke and effect inga raising of the trip means with the presser head during its upward movement, said trip means during said upward movement first having lost motion movement relative to the cross head and then raising the cross head to effect an ejection of a formed block from the mold blocks, means operable by the trip means during said lost motion movement to eflect a forced initial raising movement to thecross head prior to the raising thereof by the trip means, and said looking means being operable to release the trip means and permit a lowering of the cross head.

15. In a machine of the class described,means for raising a molded block to ejected position above a mold in which it is formed, releasable means for holding the ejecting means in raised position, a take-off carriage mounted for movement under a raised block in spaced relation thereto, means operable .to release said releasable means to permit a lowering of the ejector means, and means for guiding the carriage movements and operable to raise the carriage-into supporting engagement with the block when thereunder preparatory to a lowering of the ejector means.

16. In a machine of the class described, means operable to raise a molded block to ejected position above a mold in which it is formed, releasable means for holding the ejector means in raised position, a take-ofi carriage mounted for movement undena raised block out of engagement therewith, and means for guiding the carriage movements and operable to raise the carriage into supporting engagement with the block when thereunder and then to release said releasable means to permit a lowering of the ejector means to inoperative position.

17. In a machine of the class described wherein a presser head vertically reciprocates over a mold box to press material into block form therein, means having connection with said presser head during an upward movement thereof from pressing position and automatically operable by such movement of the head to elect a formed block upwardly from the mold box, a take-01f carriage mounted for movement under a raised block out of engagement therewith, and means for guiding the movements of the carriage and operable to raise the carriage into supporting engagement with the block and then to effect a release of the connection of said ejector means with the presser head to permit the ejector means to lower to inoperative position.

18. In a machine of the class described, means operable to raise a molded block to ejected position above a mold in which it is formed, releasable means for holding the ejector means in raised position, a take-oil carriage guided for predetermined movements, means automatically operable when the ejector means has reached a predetermined ejecting position to effect a movement of the carriage under a block out of engagement therewith and operable upon a lowering of the ejecting means to effect a movement of the carriage to carry-away position, and guide means for the carriage automatically operable when the carriage has moved substantially under a raised block to effect a raising of the carriage into supporting engagement with the block and then to release said releasable means to permit a lowering of the ejector means to inoperative position.

19. In a machine of the class described, means operable to raise a molded block to ejected posi-, tion above a mold in which it is formed, releasable means for holding the ejector means in raised position, a take-01f carriage guided for predetermined movements, means pneumatically operable at a predetermined point in a raising of the ejector means to efiect a movement of the carriage under a block and then pneumatically operable at a predetermined point in a lowering of the ejector means to effect an outward movement of the carriage to block carry-away position with a block thereon, and means operable to release said releasable means to permit a lowering of the ejector means to inoperative position.

20. In a machine of the class described, means operable to raise a molded block to ejected position above a mold in which it is formed, releasable means for holding the ejector means in raised position, a take-off carriage for movement under a raised block out of engagement therewith, means pneumatically operable to move the carriage to such position at a predetermined point in a raising movement of the ejectormeans and pneumatically operable to retract the carriage to carry-away position when the ejector means has lowered a predetermined extent from block ejecting position, and means controlled by movement of said carriage operating means and automatically operable to raise the carriage into supporting engagement with the block and then to release said releasable means to permit a low ering of the ejector means to inoperative position.

21. In a machine of the class described including a tamping means and wherein a mold box is horizontally movable to and from tamping position, transfer means operable to move the mold to and from tamping position, control means automatically operable to effect operation of the tamping means when the mold box has been moved to tamping position, and means rendered operative by operation of the tamping means to cause the tamping means to have a predetermined number of tamping strokes and then to stop the tamping action.

22. In a machine of the class described including a vertically reciprocable tamping means and wherein a mold box is movable horizontally to and from tamping position, a fluid pressure operated transfer means operable to move the mold box. to and from tamping position, fluid pressure operating means for the tamping means to impart a tamping stroke to the tamping means and then to retract it, and means cooperating with said last fluid pressure operating means to cause a predetermined number of tamping strokes to be imparted to the tamping means and then to stop the tamping action.

23. In a machine of the class described wherein a mold box is horizontally movable to and from tamping position and a tamping head operates over the mold box, transfer means for the mold box operable by fluid pressure to move the box to and from tamping position, fluid pressure operating means for imparting a tamping stroke to the tamping head and then to retract the head, control means for said fluid pressure oper ated means automatically operable by the transfer means to start actuation of said fluid pressure means to operate the tamping head when the mold box has been transferred to tamping position, and means automatically operable in cooperation with said control means to cause the tamping means torepeat its tampingstroke a predetermined number of times and then to discontinue the tamping action.

24. In a machine of the'class described, the combination with a vertically reciprocable tamping head and a mold box horizontally transferable to and from tamping position beneath the head, of means including a cylinder and plunger operated by fluid pressure to impart reciprocatory movements to the tamping head, means operable to impart transfer movements to the mold box to and from tamping position, a reverse valve operable to admit fluid operating pressure first to one end and then the other of said cylinder to operate the pressure head, means operable by the transfer means when the box has been moved to tamping position to operate said valve to admit fluid pressure to the upper end of the cylinder to impart a down'stroke to the presser head, mean automatically operable at the end of the down stroke of the presser head to impart reverse movement to said valve to cause a raising of the presser head, and means automatically operable tocause a predetermined number of repeats of the tamping strokes of the presser head and then to stop the tamping action.

25. In a machine of the class described, a mold box horizontally shiitable to and fromtamping position, a tamping head reciprocally movable vertically over the mold box when in tamping position, means operatedby fluid pressure for imparting a tamping stroke to said head and i 'then to return it to raised position, means oper-

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