US3068543A - Method for shaping appendages on ceramic articles - Google Patents

Description

Dec. 18, 1962 A. J. WAHL ETAL 3,068,543

METHOD FOR SHAPING APPENDAGES ON CERAMIC ARTICLES Original Filed June 15, 1956 7 Sheets-Sheet l 7 //v VENTORS A/berl J. Wah/ John E Lux Robe/l E Gould ATTORNEYS METHOD FOR SHAPING APPENDAGES ON CERAMIC ARTICLES ATTORNEYS 7 Sheets-Sheet 3 d a 5 5 M. II a 65% w 6 3 3 2 2 0 2 o 6 M w a s o 7 WML E H .||ufllul..... 5 a F m w m v n m n n 9 W m M 0 1| 5 J R W A 4 W 4 3 W 5 w m M n 7 w u 1 w ///74////////. A W [as 8 1 0 W 2 w Dec. 18, 1962 A. J. WAHL ETAL METi- IOD FOR SHAPING APPENDAGES ON CERAMIC ARTICLES Original Filed June 15, 1956 Dec. 18, 1962 A. J. WAHL ETAL 3,063,543

METHOD FOR SHAPING APPENDAGES 0N CERAMIC ARTICLES M219 Sheets/51w 4 Original Filed June 15, 1956 Albert J. Wah/ John F. Lax Robert E. Gould A Man eys Dec. 18, 1962 A. J. WAHL ETAL 3,

METHOD FOR SHAPING APPENDAGES' ON CERAMIC ARTICLES Original Filed June 15, 1-956 7 Sheets-Sheet 5 IN l/E/V 7055 Albert J. Wah/ John F Lux Robert 57 Gould ATTORNEYS 1386- 18, 1952 A. J. WAHL ETAL METHOD FOR SHAPING APPENDAGES ON CERAMIC ARTICLES 7 Sheets-Sheet 6 Original Filed June 1 INVENTORS Albert J Wahl Jbhn l-T Lux A TTOR/VEYS Dec. 18, 1962 A. J. WAHL ETAL 3,068,543

METHOD FOR SHAPING APPENDAGES 0N CEIRAMIG ARTICLES Original Filed June 15, 1956 7 Sheets-Sheet '7 1 INVENTORS "a Albert ,1. mm/

John F. Lux

Robert 5. 6011/0 BY W AE ORNEY$ United States Patent 3,068,543 METHQD FGR SHAPENG APEENDAGES @N CERAME ARTECLES Albert J. Wahi, Portland Township, .lohn F. Lax, Eggertsville, and Robert E. Gould, East Aurora, Nflfl, assignors to Buffalo China, Inc, a corporation of New York riginai application ions 15, 1956, tier. No. 591,786, now Patent No. 2,995,796, dated Aug. 15, 1961. Divided and this application den. 14, 196i Ser. No. 2,548

4 Qlaims. (Ql. ZS-dS) This invention relates to improvements in methods for making ceramic articles with appendages, and more particularly to improvements in methods for the final shaping of a handle blank or other appendage, molded integrally with the ceramic article.

This application is a division of our copending application Serial No. 591,706, filed on June 15, 1956, now Patent No. 2,995,796, issued August 15, 1961.

Ceramic containers, such as cups and bowls, have been made in the past with integral appendages, such as handles, in order to avoid the formation of slight cracks or checks where the handle is attached to the container, as such defects may become the unhealthful breeding place of bacteria. In the ceramic art, such integral appendaged handles on containers are known as Sanitas handles and are either molded integrally with the container of the same material and subsequently finished by hand or are preformed and arranged in a mold so that the body of the cup, or other container, is molded around the ends of the handle. Both of these methods are expensive and relatively slow as compared to the manufacture of containers with handles which are stuck to the outside of the containers.

A third method has recently been practiced in which a handle blank is premolded integrally with the container, which is then partially dried so that the ceramic is in a plastic, yet form-retaining, state, and the handle is then trimmed and shaped to its finished contours by a set of dies which are pressed together. Difficulty has been experienced in the practice of this method due to rupturing, fracturing, and the setting up of strains in the handle and in the cup body adjacent to the handle during the reshaping of the handle blank.

The original molding of one-piece china or pottery containers and handles generally is done with a water content of 19% to 22% in the ceramic material, with the preferred practical range somewhat narrower than this. Ceramic materials with this Water content are too plastic to retain their shape and must be partially dried in order to permit handling of the molded articles without distortion. Such partially dried ceramic material has been found not to be readily workable without the development of defects, even when considerable care is exercised in cutting away excess material and in pressing or reshaping the contours of a handle.

In the preparation of china or other types of white tableware bodies which are to be shaped into useful articles by a plastic molding process, it is customary to form the desired mixtures of various clays and other materials, such as ground quartz, feldspar, and the like, in the proper proportion in water. The resultant material is then passed through a screen to remove foreign substances and the screened, or filtered material, known in the trade as slip, is then dewatered. This dewatering process usually involves forcing the slip into chambers under pressure. The pressure thus applied to the slip tends to squeeze or crowd together the grains of solid material into what may be considered as a close rearrangement or touching together of the solid grains, with the remaining water distributed in the interstices "ice or cavities between the grains of solid material. This forms a filter press cake which is in a relatively nonplastic condition so that it cannot be distorted to any practical degree without fracture.

It has been found that if a filter press cake is put through a pug mill in which the cakes are sliced by rotating knives, kneaded, and forced together under pressure, the resultant material becomes plastic and moldable. The plasticity and moldable condition of the ceramic material varies with different types of clays and with the amount of water which remains in the filter press cake. This treatment of the partially dried ceramic indicates that the pulp mill treatment restores plasticity to the material by the redistribution of the water around the solid grains and out of the interstices, which permits the solid grains to slip more readily one over the other so as to induce a plastic moldable property in the semidry ceramic. According to the present invention, this thioxotropic property of various ceramic materials, in which the chief ingredient is clay, is utilized in forming or reshaping a p-remolded integral handle blank and container into a container with a handle having the desired contours.

In preforming an integral ceramic container and handle for use in practicing this invention, it is desirable that the ceramic material be forced under pressure into a one-piece plaster-of-Paris or metal mold, so as to eliminate fins and minimize manual finishing of the article. The material used in thus forming the molded container and handle blank is generally found to be in its most workable condition with a water content of 21% or 22%, although, as previously noted, the range may vary somewhat for dilferent materials. In order to make it possible to remove the molded article from the mold without distorting it, the Water content must be reduced or the material dried until it contains about 16% or 18% water. This water content is about the maximum moisture which a ceramic article can contain and be removed from a mold in a safe and practical manner. It is a condition of the ceramic which may be said to be a plastic formretaining state of the material.

In the improved method of reshaping an integral ceramic container and handle according to this invention, it has been found that the thiX-otropic property of the material is most advantageously utilized by the sudden application of the-cutting or punching and reshaping force to the semi-dried or plastic form-retaining ceramic material, within a confined space, that is, while supporting the handle blank material, to a certain degree, in all directions by a die or similar shaping tool. This permits the material of the handle to become moldably plastic, without fracturing or deforming the handle or the body of the container. It also has been found that the size or thickness of the handle which is to be reshaped affects the restoration of plasticity to the ceramic material by the thixotropic molding method practiced according to this invention, such that a larger section of material requires a relatively higher water content than does a smaller or thinner section handle. The reduction of the water content below 16% has been found generally not to allow for practical working of the ceramic without undesirable ruptures. An average of about 17% water content has been found to be the most generally practical for the practice of this invention.

An apparatus has been constructed for carrying out the present improved method of making a ceramic container with an integral handle and for shaping the handle from a handle blank premolded integrally with the container, which sequentially and automatically reshapes the handle blank by suddenly applying a reshaping force thereto, and then restores the apparatus to its starting position on removal of the finished article therefrom. This apparatus comprises a set of dies which close with a snap action and provide a certain amount of support to the handle blank in all directions, while closing and punching off excess material from the handle blank and reshaping the contours of the material within the dies. The dies are then opened, punched or cut-off material is ejected from the dies, and the faces of the dies are reoiled to prevent sticking of ceramic material thereto during the next cycle of operation. A machine for carrying out these functions has been built in which the snap action of the dies is obtained by tripping a spring-actuated mechanism, and pneumatic actuators provide the operating power for the other operations. An electrical system provides the desired sequential operating control and certain safety holding circuits to assure against accidental non-sequential operation which might damage an article undergoing reshaping by the machine.

An object of the present invention is to provide an improved method of making an integral ceramic container and appendage.

A further object of this invention is to provide an improved method for finishing the contours of a ceramic handle blank premolded integrally with the body of a container.

Further objects and advantages of this invention will become apparent upon an understanding of the illustrative embodiment of this invention hereinafter described or as indicated in the appended claims, and various additional advantages will occur to one skilled in the art upon employment of the invention in practice.

A preferred embodiment of the invention has been chosen for purposes of illustration and description and is shown in the accompanying drawings, forming a part of this specification, wherein:

FIG. 1 is a side elevational view, partly broken away and partly in section, taken along line 1-1 of FIG. 4, of a machine embodying this invention, in which the electrical circuits, pneumatic or fluid connections, and die lubricators are omitted for purposes of more clearly illustrating the mechanical relationships and arrangement of certain mechanical operating parts of the machine, shown in initial starting positions of an operating cycle;

FIG. 2 is a plan view of the machine shown in FIG. 1, with part of the cover plate broken away and with the handle forming dies in closed position and parts of the die operating links under the cup supporting chum shown in dotted lines in order to better illustrate these operating linkages;

FIG. 3 is a plan view illustrating the dies and their operating linkages in open die positions, and the handle aligning guide in its aligning position corresponding to the initial or starting position of these parts of the machine at the beginning of an operating cycle;

FIG. 4 is a sectional view, taken along line 44 of FIG. 1, illustrating details of the crank mechanism and related operating parts for providing snap action closing of the handle-forming dies;

FIG. 5 is a sectional view through a portion of a cup and handle with the dies in closed die positions, illustrating the final handle shaping positions of the dies;

FIG. 6 is a perspective View of one of the handle-forming dies, illustrating details of a die face;

FIG. 7 is a longitudinal sectional view, along line 7-7 of FIG. 6, illustrating the ejector mechanism in a die;

FIG. 8 is a schematic representation of the prinicpal Operating parts of the apparatus, showing their relationship at the beginning of an operating cycle;

FIG. 9 is a perspective view of the main supporting framework of the apparatus and the mountings of certain of the principal operating parts, other than the dies and their mountings;

FIG. 10 is a schematic plan view, taken along line 10-10 of FIG. 8, with the churn, dies, and the upper die linkages removed, to illustrate more clearly the relative positions of the actuating mechanism and the control switches in their positions at the start of an operating cycle;

FIG. 11 is a schematic diagram of the mechanism shown in FIG. 10 illustrating the relative positions of the operating elements in the closed die positions;

FIG. 12 is a schematic diagram illustrating the operating mechanism shown in FEGS. 10 and 11, illustrating the mechanism in the position in which the die operating spring actuated crank is returned to its open-die position; and

FIG. 13 is a schematic circuit diagram of the electrical control system for the apparatus illustrated in the remaining figures of the drawings.

General Structure The improved method of making an integral container and handle in accordance wth this invention may be practiced by the utilization of any desired convenient ap paratus and, for illustrative purposes, will be described in connection with the accompanying drawings, which illustrate a preferred embodiment of apparatus for carrying out the improved method. This apparatus comprises a machine adapted to utilize the thixotropic property of semi-dry ceramic material of becoming workably plastic by the sudden application of a reshaping force to the material within a confined space. Such treatment can best be provided by a snap action closure of the shaping tool and requires equipment capable of absorbing a sudden jar for each cycle of operation.

In order to assure a long useful life to the apparatus, the operating mechanism is mounted upon a sturdy main supporting frame, having a generally rectangular form and preferably being constructed of simple structural steel sections rigidly welded together. As is more clearly shown in FIG. 9, a good example of such a frame comprises an angle section post 1 extending upwardly at each front corner, and shorter angle section posts 2, secured, as by welding, to channel section feet 3, forming the rear corner posts of the frame. A rigid structure is provided by securing together the upper ends and lower ends, respectively, of the front posts 1 and the rear posts 2 by transversely extending channel section cross-bars 4 and 5, and rigidly connecting the front posts 1 to the rear posts 2 adjacent the upper ends and lower ends, respectively, by side bars 6 and 7.

According to the present invention, the cup, or other container, is integrally premolded with a blank handle appendage extending laterally therefrom, and the moisture content of the ceramic material then is reduced to between 16% and 18%, so that the article can be handled without damage to its molded form. It is then removed from the mold and is in condition for final shaping of the handle. This is done by the improved apparatus of the present invention, and a cup 8 is adapted to have its handle reshaped by placing it upon a suitable churn 9 in inverted position, with its handle blank 10 extending to the rear thereof, as shown in FIG. 8. The chum supports the cup 8 in approximately centered position on the handle shaping machine for the reshaping operation. This supporting chum 9 is made somewhat smaller than the inside or" the cup, or other container, which is to be mounted thereon, so as to provide for loosely supporting the container to permit a slight shifting thereof during the reshaping of the handle. This allows excess material which is punched or pressed from the outer contours of the handle blank adjacent the cup body to pass from the dies without damaging the cup or the handle. It has been found that this loose fit of a cup on its supporting chum is very important in order to avoid a high percentage of fractures.

In order to accommodate different sizes and shapes of containers, a variety of sizes and shapes of chums may be provided. These chums are readily interchanged by simply unbolting and withdrawing a through bolt 11,

which pivotally supports the front end of the churn. This bolt 11 extends through a pair of downwardly extending cars 12 on opposite sides of the front edge of the churn and a pair of upwardly extending mounting brackets 13, rigidly secured, as by welding, to the upper side of a cover plate 14. The cover plate 14- preferably is a thin metal plate permanently secured over the main frame, as by welding to the upper cross bars 4 and the side bars 6. This further assures the rigidity and sturdiness of the machine.

The rear end of the chum 9 loosely rests upon the upper end of a push rod 15, slidably mounted within a channel 16 and resiliently biased upwardly by a suitable compression spring 17 which thus provides a resilient support for the chum. The spring 17 is arranged around the push rod between a collar 18 fixedly secured to the rod and a supporting guide bracket 19 fixedly secured in the channel 16. This provides a resilient biased depressible chum support which is utilized to control a safety holding circuit in the electrical control system for the apparatus. so that the presence of a cup on the chum assures against accidental non-sequential operation which might damage a cup. The operation of the safety circuit is controlled through the push rod which is slidably fitted in an opening in the bracket 19, which thereby serves as a guide bearing for the rod 15 and provides a simple push rod switch control.

Article Aligning The proper alignment of the cup and handle blank on the apparatus is highly important in order to obtain the requisite simultaneous pressure on opposite sides of ti". handle blank during its reshaping. In placing a cup 8 on the chum, the handle blank 16 is placed to the rear and into an aligning groove 20 in a guide block 21, suitably mounted, as by screws 22, on a cross arm 23 secured to the upper end of an upwardly extending operating column 24. This handle aligning guide operating column 24 is controllably rockably mounted for movement or" the guide block 21 from and to handle aligning position, when the electrical control circuit is energized, depending upon the presence or absence, respectively, of a cup on the churn 5. The lower end of the column 24 is suitably secured, as by welding, to a transversely extending shaft 25, which is rotatably supported by journal bearings 26 secured by bolts 27 to the channel section feet 3, to provide for the to and fro movement of the upper end of the column 24 and of the guide block 21.

Actuation of the aligning guide column 24 may be provided by any suitable source of power, as by a fluid or pneumatic power cylinder 28, provided with a piston (not shown) connected to a piston rod 29, pivotally connected through a clevis 3t and a pivot pin 31 to a tongue 32 fixedly secured, as by welding, to the operating column 24. The end of the power cylinder 28 opposite the piston rod end is pivotally supported by a mounting flange 33 rigidly secured to the end of the cylinder and pivotally supported by a pivot pin 34 on a pair of stationary bracket arms 35 fixedly secured, as by welding, to the upper front cross bar 4 of the main supporting frame. This provides for free pivotal adjustment of the actuating power cylinder 28 and its alignment with the guide operating column 24, as it moves to and from aligning position.

Control of the operation of the power cylinder 28 is provided by an electrical circuit, schematically illustrated in FIG. 13. This circuit includes a main power system circuit breaker or switch 36, of any suitable type, for connecting and disconnecting the control circuit to a source of electric power supply 37. A suitable valve, such as a solenoid valve 38, controls the supply or" fluid or air from a source of fluid pressure 39 to the power cylinder and is operable by a suitable solenoid 4G. Energization of the solenoid 49 is obtained by connecting one side to the source of electrical power supply through a suitable conductor 41 and the other side through contacts 42 and contactor 43 of a relay 44 and a conductor 45 The relay 44 is operable by an excitig winding 46 connected to the source of electrical power supply through the conductor 41 and through manually operable, normally open, circuit breaker 47 such as a treadle switch connected to the conductor 45.

Under starting conditions, the main switch 36 is closed and the treadle switch 47 is open, so that the relay coil 46 is deenergized and the relay contacts are open. In this condition the fluid valve solenoid is deenergized, as its energizing circuit is open through the open contacts 42 and contactor 43 of the relay 44. This fluid valve is suitably connected to the fluid pressure source 39 and the power cylinder so constructed that, when the solenoid 40 is deenergized, the power cylinder piston retracts the piston rod 29 and rocks the guide operating column 24 to handle aligning guide position, as shown in FIGS. 1, 3, 8, 9 and 10, and places the guide block 21 in position for reception and alignment of a handle blank.

When a cup 8 is placed upon the chum 9, with its blank handle appendage l0 aligned in the aligning groove 26 of the guide block 21, the chum 9 is depressed under the pressure of the weight of the cup thereon, and the push rod 15 is resiliently pushed downwardly against the pressure of the spring 17. The lower end of the push rod 15 operably engages an electric switch operating handle 43 through a suitable connection, such as a clevis 49 connected to the handle 48 through a pivot pin 50. Depression of the push rod 15 is adapted to operate the switch handle 48 so as to close a normally open circuit breaker 51, such as a micro-switch, and thereby establish a holding circuit for maintaining the relay coil 46 energized through the micro-switch 51, and contacts 52 and contactor 53 of the relay 44. Thus, even if pressure on the treadle switch 47 were to be released and this circuit opened, the presence of a cup, or other container, on the chum 9 would keep the micro-switch 51 closed and the relay coil 46 energized through the safety holding circuit including the micro-switch 51 and the relay contacts 52 and contactor 53. This safety holding circuit assures energization of the valve solenoid through the relay 44 as long as a cup rests on the chum 9, and thus assures that the guide 21 will remain out of its handle aligning position after it has been moved initially away from a cup on the chum and until the cup is removed and pressure released from the handle 48 of the micro-switch 51.

A ppendage Reshaping After the container 8 and its handle blank 10 have been properly aligned in their position on the supporting churn 9 and the aligning guide 21 has been moved out of handle aligning position, the apparatus is adapted automatically to reshape the handle blank by the sudden closing of a pair of dies 54 simultaneously on opposite sides of the handle blank. Each handle forming die preferably is made with a similar complementary face 55, FIGS. 5, 6, and 7, with an inner wall 56 corresponding to the complement of the shape of the handle adjacent to the cup and an outer wall 57 corresponding to the complement of half the outer contours of the finished handle. In the center of each face is a central opening 58 surrounded by a central wall 59, corresponding to the complement of half the contours of the finger hole through a finished handle. Each die 54 is formed with a cylindrical supporting housing 60 mounted on a bracket 61, fixedly secured to the free end 62 of an arm' 63 of a bell crank. The free end 64 of the other arm 65 of each bell crank is coaxially pivotally supported eccentrically relative to the cup supporting churn 9 on a stub shaft 66, journalled in a long sleeve bearing 67 which extends downwardly through an opening in the cover plate 14 and is detachably secured thereto by bolts 68. This mounting of the dies 54 provides for simultaneously swinging them in opposite directions along arcuate paths of larger radius than the radius of the cup 8 and for closing them with the inner sides of the inner walls 56 thereof substantially tangent to the outer surface of a cup on the chum 9, as shown in FIGS. 2 and 5. This provides for a minimum of excess ceramic material being scraped or punched off or pressed out from the dies along the sides of the cup, and thus minimizes the tendency of such material to press the cup body away from its handle and cause fractures or strains in the cup or its handle. The combination of this improved method of closing the dies with the use of a chum slightly smaller than the inside of the container provides for greatly improved results in reshaping of the handles with negligible damage to the cups and handles from fractures or strains due to the reshaping operation.

In order to provide for reshaping different styles of handles by correspondingly different dies, the die supporting housings 60 are secured to the brackets 61 by detachable straps 69 extending over the housings and suitably fastened by bolts 70 to the brackets 61. Also, the vertical position of the pivotal mounting of the bell cranks can be adjusted, to a degree, by a vertically ad justable support for the stub shaft 66. This support comprises a thrust plate 71, mounted on the end of an adjusting screw 72, threadedly engaging a mounting sleeve 73 depending from a supporting bracket 74. This supporting bracket is rigidly secured, as by a screw 75, to the guide channel 16, which is suitably secured, as by welding, to the rear top cross bar 4 of the main frame. Vertical adjustment of the screw 72 provides a corre sponding adjustment in the vertical position of the stub shaft 66 and of the die mounting brackets 61. Final adjustment is set by tightening of a lock nut 76 on the screw 72. Such adjustment is limited, however, due to the related operating connections of the bell cranks to the dies.

The desired snap action closing of the dies 54 for abrupt, sudden or shock working of the ceramic is provided by actuating these dies to closed die positions by a trigger release, spring actuated mechanism. This mechanism includes an arrangement for simultaneously actuating the two dies and comprises a crank 77 pivotally secured, at one end 78 thereof, to a pair of links 79, each pivotally connected to the elbow 80 of one of the die supporting bell cranks. The crank 77 is fixedly mounted on an upwardly extending drive shaft 81 and forms a driving connection with the upper end thereof, for transmitting power from the shaft 81 to the dies 54. The shaft 81 is rotatably supported adjacent its upper end by a sleeve bearing clamp 82, suitably fastened, as by screws 83, to one of the upper side bars 8 of the main frame of the machine. The lower end of the drive shaft 81 is supported by a thrust and bearing mounted in a bracket 84 suitably secured, as by screws 85, to one of the lower side bars 7 of the main frame of the machine. Actuation of the drive shaft 81 is provided through a spring actuated crank 86 rigidly secured to a collar 87 having a fixed driving connection with the lower end of the drive shaft 81. Thus, a turning of the crank 86 produces a corresponding turning of the drive shaft 81 and of the upper crank 77, which transmits this motion through the links 79 to the bell crank elbows 80, the crank arms 63, the brackets 61, and the housings 60, to the dies 54.

At the beginning of an operating cycle, the actuating crank 86 is latched in extended open-die position as shown in FIGS. 1, 4, 8, 9 and 10, by a step 88 on a latching bar 89. This latching bar is pivotally mounted, as by welding, to the underside of a sleeve 90 supported by a pivot pin 91, on a pair of bracket arms 92. These arms 92 are mounted on a base plate 93, which extends between and is fixedly secured, as by welding to the lower cross arms of the main frame of the machine.

The latching bar 89 is resiliently biased into latching errgagement with the end of the actuating crank 86 by a compression spring 94, seated on the base plate 93, and a main actuating tension spring 95 is secured to the crank 36 and biases it into firm latching engagement with the step 88 on the latching bar. The other end of the main tension spring 95 is secured to a suitable anchoring eyelet 96, preferably adjustable to provide for adjustment of the operating tension of the main spring 95 for varying the tension of this springas required for proper reshaping of handle blanks of various sizes and materials.

This adjustment of the main actuating spring 95 may be provided in any suitable manner, as schematically illustrated in FIGS. l0, l1 and 12, by a simple conventional threaded eyelet shank 97 and wing nuts 98, which cooperate with a suitable stationary bracket 99 or may comprise a linkage for providing a wider range of adjust ment, as shown in FIGS. 1, 2 and 4. The latter linkage includes a crank 100 to which the main spring 95 is connected by an eyelet or pin 96. The spring tension is adapted to be varied by shifting the position of the spring crank 1011 around its pivotal mounting to one of the rear corner posts 2 of the main frame. This pivotal mounting is conveniently provided by a pivot pin in the form of a bolt 1&1, extending through the crank 100 and a mounting plate Hi2 secured to a rear corner post 2. In order to provide for adjustment of the spring tension, the other end of the spring crank 109 is secured to the lower end 183 of an operating handle 104 by a suitable pivot pin 1115 extending through a boss 106 on the crank 100. The

handle 104 is provided with a conventional pawl 107 and ratchet 108 mounted on one of the rear frame posts 2 and a conventional pawl release rod and linkage 109 on the handle for releasing the spring biased pawl when it is desired to shift the handle 104 to release the tension on the main spring 95. To increase the spring tension the handle is pulled forward, that is to the left, in FIGS. 1, 2 and 4. This turns the lower end 103 of the handle to the right in these figures, and the pawl 107 rides over the ratchet teeth to hold the handle 104 and, therefore, the crank 1% is in any desired position of spring tension.

Sequential Reshaping Operation In the initial operating position of the apparatus, when the main line circuit breaker 36 is closed, connecting electric power to the control circuit, and the handle aligning guide 21 and its operating column 24 are in handle aligning position, as shown in FIGS. 1, 8, l0- and 13, an operating arm 111) fixedly secured to the shaft 25, to which the column 24 is secured, is in its lower position with the free end 111 thereof in engagement with a roller 112 on an operating handle 113 of a normally open circuit breaker 114, such as a micro-switch. In this position,'the arm depresses the switch handle 113 and biases the switch 114- to closed circuit position. This energizes an exciting winding 115 of a relay 116 by connecting it to the source of electric power supply 37 through conductors 117 and 118. This closes relay 116 and completes a holding circuit for the relay coil 115 through relay contacts 119 and contactor 120 and a normally closed circuit breaker 121, such as a micro-switch.

Closing of the relay 116 also closes a circuit through relay contacts 122 and contactor 123 and a solenoid 124 of a fluid or pneumatic solenoid valve 125, which controls the flow of pressure to a power cylinder 126 from a source of fluid pressure 127, This power cylinder 126 i provided with a piston (not shown) connected to a piston rod 128 pivotally connected at its outer end through a clevis 129 and a pivot pin 130 to a resetting arm 131 adapted to reset the spring biased actuating crank 86 in its spring tensioned open die position. In this position of the solenoid valve 125, the piston of the power cylinder 126 is retracted so as to draw the resetting arm 131 away from the actuating crank 86 and against a suitable stop 132. The end of the power cylinder 126 away from the piston rod 128 is suitably pivotally mounted by a flange 133 secured to the cylinder to allow slight pivotal adjustment of the cylinder as it operates the arm 131. This flange 133 extends between a pair of cross bars 134 secured to the rear posts '2 of the main frame of the machine, and a pivot pin, such as a bolt 135 secures the flange 133 to the cross bars 134.

When a cup 8 is placed on the churn 9 and the treadle switch 47 is depressed, so as to energize relay 44 and, therefore, solenoid 40, the valve 38 supplies fluid pressure to the power cylinder 28, so as to rock the guide column 24 and guide 21 out of handle aligning position. This rocking of the guide column 24 turns the shaft 25 to which it is secured and raises the operating arms 110, and thus releases pressure on-the switch handle 113 and allows the switch 114 to assume its normally open position. The opening of switch "114 under these conditions does not affect any of the controls, as the relay coil 115 remains energized through it holding circuit established through the normally closed switch 121 and the relay contacts 119 and contactor 126.

Rocking of the guide column 24- -to its fully open position away from its handle aligning position, raises the free end 111 of the operating arm 110 into engagement with the adjacent end 136 of the latching bar 89 and rocks it around its pivotal mounting 91, so as to raise the end 136 and lower the opposite stepped end 88. This has the effect of triggering or releasing the spring actuated crank 86 from it latched position against the step 88 and, under the tension of the main spring 95, the crank 86 swings around toward the resetting arm 131.

This spring actuation of the crank 86 rotates the drive shaft 81, which correspondingly swings the crank 77, the links 79, and the bell cranks, from the positions shown in FEGS. 3, 4 and 10, so as to snap closed the dies 54 to the positions shown in FIGS. 2 and 11. As these dies close on a handle blank 10, excess ceramic material is punched off the outer contours of the handle, and the inner contours of the finger hole are formed by a combined punching and compressing or pressure molding, with exces material 137 being forced into the central openings 58 of the dies, as shown in FIG. 5.

Swinging of the spring actuated crank 86 to closed die position, as shown in dotted lines in FIG. 4, and more clearly in FIG. ll, causes the side of the crank 36 to engage an upwardly extending roller 138 on an operating handle 139 of the normally closed circuit breaker 121 and to bias it to open circuit position. This opens the holding circuit of the relay 116 and deenergizes the relay coil 115, which opens the relay and deenergize the solenoid 124 through the relay contacts 122. In deenergized solenoid position, the solenoid valve 125 admits fluid pressure to the power cylinder 126 from the source 127. This extends the piston rod 128, which extends the resetting arm 131 towards the actuating crank 86, so that a finger 149, secured to the end of the arm 13-1, engages the crank 86 and swings it back until it engages a stop 141 secured to the base plate 93, as shown in FIG, 12. This return swing of the crank 86 turns the drive shaft 81 through a corresponding angle and likewise swings the crank '77. This draws the links 79 and the bell cranks back to their starting positions and swings the dies 54 back to the open die positions, as shown in FIGS. 1 and 3.

As shown in FIG. 5, the material punched from the finger hole, in forming the handle, passes into the central openings of the dies 54. It is essential that this material be cleaned from the dies after each cycle of operation to prevent clogging of the dies and thereby rendering impossible further shaping of the finger holes in the handles. As is more clearly shown in the sectional view, in RG. 7, an ejector plunger 142 is arranged in the central opening 58 in the die and is resiliently biased to the rear of the opening by a compression spring 143 seated between a shoulder 144 in the die housing 60 and collar 145 secured to an ejector stem 146, which extends away from the face of the die. A suitable screw cap 147 threadedly engages the end of the die housing 613 and holds the collar 145 in place and provides a guide for the end of the ejector stem 146 which extends through a central opening in the cap 147.

Swinging the dies 54 to open die positions, as shown in FIG. 3, brings the outer ends of the ejector stems 146 into engagement with stops 143 before the dies 54- are fully open. The further movement of the dies to full open positions causes the die housings 60 to slide along the ejector stems 146, moving the housing shoulders 144 toward the stem collars 145, and forcibly moving the ejector plungers 140 forwardly through the central openings 58 of the dies and effectively ejecting the ceramic material therefrom. This thoroughly cleans the inside of the dies for the next cycle of operation.

Provision also is made to prevent sticking of ceramic material to the faces of the dies by supplying a thin film of oil over the faces after each operation. An oiling mixture of about kerosene and 10% lard oil is conveniently stored in a pair of oilers 149 mounted on a bracket 150, secured to the rear end posts 2 of the main frame of the machine. Suitable drip tubes 151 extend from the oilers to positions directly over the faces of the dies in open die positions, and the oily mixture is slowly dripped from the oiler tubes 151 over the faces of the dies. This material spreads very easily and forms a thin film which prevents sticking of the ceramic to the dies, without any injurious effects to the ceramic comprising the handles.

Return of the actuating crank 86 to its open die position, as shown in FIG. 12, releases pressure on switch handle 139 of the normally closed switch 121 and closes this switch. This resets the switch for the initial operating position of the apparatus, but does not, however, establish any closed electric circuit, as the relay 116 is deenergized and its contact 119, in series with the switch 121, are open under this condition.

Return to Starting Position At this point, the shaping of the cup handle has been completed, and the cup may be removed from the chum 9 and pressure on the treadle switch 47 released. This opens both switches 51 and 47, which deenergizes relay 14 and opens the circuit of the solenoid 41 thus actuating the valve 38 to remove fluid pressure from the power cylinder 28, so as to cause retraction of the piston rod 29. This rocks the guide column 24 back to handle aligning position of the guide 21 and lowers the free end 111 of arm Lowering of this arm releases pressure on the end of the latching bar 39, and compression spring 94 biases the step 88 of the latching bar 89 upwardly and back into latching engagement with the end of the spring actuated crank 86.

Lowering of arm 116 also causes its free end 111 to reengage and depress handle 113 of normally open switch 114, thus closing the energizing circuit of relay coil 115 and closing this relay. Closure of this relay reenergizes solenoid 124 through relay contacts 122 and contactor 123, which causes the solenoid valve 125 to cut off pressure from power cylinder 126. This retracts piston rod 128 thus retracting the resetting arm 131 to its initial position against the stop 132, out of the path of travel of the spring actuated crank 36, and completely restores the apparatus to its initial starting condition.

It is thus seen that the present invention provides a new and improved method for forming ceramic containers with integral handles by taking advantage of the thixotropic property of ceramics under certain moisture content conditions. The method is adapted for automatically carrying out the desired sequence of operations and permits the use of novel and improved features for eliminating the manufacturing defects and strains in the ceramic containers and the handles.

Obviously, various changes may be made in the method Without departing from the spirit and scope of this invention and without sacrificing any of its advantages; It is to be understood, therefore, that the matter herein is to be interpreted as illustrative and not in a limiting sense.

Having thus described our invention, we claim:

1. A method of making a ceramic cup with an integral handle which comprises first molding plastic ceramic material having thixotropic properties to form the cup in one piece with handle blank extending therefrom, drying the cup to a firm form retaining degree, and thereafter shaping the handle from the handle blank by a sudden closing of dies thereon at a high impact speed sufliciently great to restore plasticity in the dried handle blank by virtue of the thixotropic condition thereof which combined with the impact blow of the dies renders the dried and firm handle blank soft and workable.

2. A method of making a ceramic cup with an integral handle which comprises first molding plastic ceramic material having thixotropic properties into semi-finished form in one piece with a handle blank extending therefrom, drying the molded form to a firm shape retaining degree, and thereafter shaping the handle from the handle blank by a sudden closing of dies thereon at a high impact speed sufiiciently great to restore plasticity in the dried handle blank by virtue of the thixotropic condition therein which combined with the impact blow of the dies renders the dried and firm handle blank soft and Workable.

3. A method of making a-ceramic cup with an integral handle which comprises molding plastic ceramic material having thixotropic properties into semi-finished form in one piece with a handle blank extending therefrom,

drying the molded form to a firm shape retaining degree, and thereafter shaping the handle from the handle blank by a sudden closing of a pair of dies thereon at a high impact speed sufficiently great to restore plasticity in the blank by virtue of the thixotropic condition therein which combined with the impact blow of the dies renders the dried and firm handle blank soft and workable.

4. A method of making a ceramic cup with an integral handle which comprises first molding plastic ceramic material having thixotropic properties to form the cup in one piece with a handle blank extending therefrom, drying the cup to a firm form retaining degree, and thereafter reshaping the handle blank and removing surplus material therefrom and forming a finger hole therein by a sudden closing of a pair of dies thereon at a high impact speed sufiiciently great to restore plasticity in the blank by virtue of the thixotropic condition of the material which combined with the impact blow of the dies renders the dried and firm handle blank soft and workable.

References Cited in the tile of this patent UNITED STATES PATENTS 409,542 Winkler Aug. 20, 1889 630,397 Niedringhaus Aug, 8, 1899 2,648,125 McKanna et al. Aug. 11, 1953 2,691,806 lanes Oct. 19, 1954 2,847,708 Hamjian et a1 Aug, 19, 1958 2,953,816 Kidder Sept. 27, 1960 OTHER REFERENCES Searle. Encyclopedia of the Ceramic Industries, vol. 2, London 1930, pp. 412-413.

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