US2856667A

US2856667A - Semi-automatic tamping machine

Info

Publication number: US2856667A
Authority: US
Publication date: 1958-10-21
Anticipated expiration: 1975-10-21

Description

Oct. 21, 1958 J. T. GORSUCH 2,856,667

SEMI-AUTOMATIC TAMPING MACHINE Filed June 18, 1954 fiyrezylbr (fa/717 T Gama/7 y W1? m5 United rates Patent O flflce 2,856,667 Patented Oct. 21, 1958 2,856,667 SEMI-AUTOMATIC TAMPIN G MACHINE Application June 18, 1954, Serial No. 437,776 2 Claims. (CI. 25-27) This invention relates to a semi-automatic tamping machine, and more particularly, to a semiautomatic machine or apparatus for uniformly and repetitively tamping or spreading clay in a mold and for applying a uniform oil film to the spread clay.

In the prior ceramic or porcelain electrical insulator manufacturing art, a ball of clay formed by hand was positioned in a mold. Then, an operator spread or tamped the ball of clay in the mold by manually pressing downwardly on the ball of clay with a felt and canvas covered mallet, plunger, or tamper. If the ball of clay is properly spread or tamped in the mold, the clay has a shape acceptable for plunging. Prior to the plunging operation, the operator applied a film of oil by hand to the spread or tamped clay. Plunging is the final forming operation wherein a heated die is used to press intricate shapes into the tamped clay. Oil is applied to the tamped clay preparatory to the plunging operation to facilitate a uniform release of the heated plunging die from the clay.

The above-described manual operations of tamping the clay and applying a film of oil to the tamped clay are slow, costly, and result in a high rate of rejection. Tamping is a very critical operation requiring considerable operator skill, and is subject to the errors of operator judgment. For instance, the operator may tamp the ball of the clay too deeply, not deep enough, or too much on one side. Also, due to a combination of errors in operator judgement and the rather crude tamper employed, sometimes the tamper was not uniformly released from the spread clay resulting in flaws such as suck and folds. Furthermore, applying oil to the tamped clay by hand preparatory to plunging did notalways result in the application of a uniform oil fihn to the tamped clay.

It is an object of this invention to remove the abovedescribed defects by providing a machine for uniformly tamping clay in a mold for uniformly applying an oil film to the tamped clay and for affecting a uniform release of the tamper from the tamped clay.

In a clay tamping tool comprising a tamper having an outer covering such as felt and canvas, my invention comprises a high pressure gas pocket or cushion formed between said tamper and covering.

In an instrument for spreading clay in a mold comprising a reciprocating plunger having an outer cloth covering such as canvas and an absorbent pad such as felttherebetween, my invention further comprises a uniform flow of a lubricating and cooling fluid such as oil to said pad through channels or grooves formed in said plunger.

My invention further comprises a machine or apparatus having an upright closed piston cylinder positioned directly above a mold holder and a tamper disposed between said cylinder and holder and connected by a piston rod to a reciprocating piston within said cylinder, a source of high pressure fluid alternately connected to opposite ends of said cylinder by a four-way spool valve and two fluid conduits connected to said valve and said opposite ends, and a two-way spring biased spool valve communicating With said source and connected by a fluid conduit to said four-Way valve for initiating downward movement of said tamper, and a vertically adjustable two-way spring biased cam operated spool valve communicating with said source and connected by a fluid conduit to said four-way spool valve for initiating upward movement of said tamper after a predetermined downward movement thereof, and a cam movable simultaneously with said tamper engageable with said cam operated valve after said predetermined downward movement.

My invention eliminates the heretofore raising and lowering of the tamper or mallet by hand, spreads the ball of clay in the mold to the same shape in each and every case, eliminates the sticking of clay to the plunger or mallet, eliminates those defects due to hand tamping, and applies a uniform coating or film of oil to the tamped clay.

The features of my invention which I believe to be novel are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawing.

In the drawing, Fig. 1 is a perspective view of a preferred form of my invention. Fig. 2 is a diagrammatic view of my preferred form of invention. Fig. 3 is a View of a tamped ball of clay. Fig. 4 is a sectional view of the tamper of my invention, the section being taken along the line 4-4 of Fig. 1. Like reference numerals will be used throughout the various figures to indicate identical parts.

Referring now particularly to Fig. 1, shown therein is a machine frame 1 having a mold holder 2 adapted to hold and center a mold 3. Within the mold 3 is positioned a ball of clay 4. An upright high pressure fluid piston cylinder Shaving its axis common with the axis of mold 3 is supported by frame 1 directly above mold holder 2 in vertically spaced relationship therewith... A tamper, plunger, or mallet 6 is adapted to be reciprocated by the piston cylinder 5. As will be more clear hereinafter, depression of a foot lever 7 initiates downward travel of the tamping tool 6 to spread or tamp the ball of clay 4 into the shape illustrated in Fig. 3. After a predetermined downward stroke of the clay spreading instrument 6, a cam or arm 8 will engage a vertically adjustable two-way spring biased cam operated spool valve 9. Actuation of valve turn movement of the tamper 6.

Referring now also to Fig. 2, a not shown source of high fluid pressure such as a tank of high air pressure is connected by a high fluid pressure conduit 10 to a fluidly operated four-way spool valve 11. Valve 11 comprises a closed cylindrical housing 12 having a slidable triple piston valve element therein. Formed in the side wall of housing 12 and distributed along the length thereof are five apertures or ports. Conduit 10 is connected to the central one of said five ports. A high fluid pressure conduit 13 is connected to the port immediately to the left of said central port and to the upper end of cylinder 5. Another high fluid pressure conduit 14 is connected to the port immediately to the right of said central port and to the lower end of cylinder 5. Each of conduits 13 and 14 has a throttle valve (VT) for a purpose well known in the art. The two endmost ports 15 and 16 of said five ports are exhaust ports in communication with the ambient air or the like.

A two-way spring biased spool valve 17 is connected to conduit 10 by a pipe or tube 18 and to the left-hand end of four-way valve 11 by a pipe or conduit 19. Twoway valve 17 which is adapted to be actuated by foot lever 7 comprises a cylindrical housing having a slidable.

spring biased double piston valve element therein.

9 by cam 8 initiates upward re- Formed in the housing side wall of two-way valve 17 are three ports or apertures distributed along the length thereof. The central one of said three ports is connected to tube 19, and tube 18 is connected to the upper one of said three ports. The lower one of said three ports is an exhaust port and is in communication with the atmosphere or the like.

Two-way vertically adjustable spring biased cam operated spool valve 9 comprises a cylindrical housing having a slidable spring biased double piston valve element therein. Formed in the housing side wall of valve 9 and distributed along the length thereof are three ports or apertures. The central one of said three ports is connected by a flexible hose 20 to the right-hand end of four-way valve 11, and the left-hand port of said three ports is connected by a flexible hose 21 to the conduit or tube 10. The right-hand port of said three ports is an exhaust port in communication with the atmosphere or the like.

The tamper 6 is connected by a piston rod 22 to a piston 23 disposed within the cylinder 5. The cam or arm 8 movable simultaneously with the tamper 6, piston rod 22, and piston 23 is adapted to engage a finger or cam arm 24 of valve 9 after a predetermined downward stroke of tamper 6 to drive the slidable spring biased double piston valve element of valve 9 leftwardly.

When the foot lever 7 is depressed, the downwardly spring biased double piston valve element of valve 17 is moved upwardly whereby tube 18 is in communication with tube 19 while the exhaust port of valve 17 is isolated therefrom. Accordingly, high pressure fluid from conduit 10 will go through tubes 18 and 19 into the left-hand end of valve 11 to drive the slidable triple piston valve element thereof towards the right. The triple piston valve element of valve 11 will remain at the right-hand end of housing 12 inasmuch as the righthand end of housing 12 is exhausted through the flexible hose 20 and exhaust port of valve 9 while the tube 21 is isolated therefrom. When the triple piston valve element of valve 11 is driven towards the right, the tubes 10 and 13 are in communication with each other and are isolated from the exhaust ports 15 and 16 and the tube 14. Accordingly, high pressure fluid will enter the upper end of cylinder 5 through the tubes 10 and 13 to drive the tamper 6 downwardly. When the tamper 6 is initiated downwardly inasmuch as the triple piston valve element of valve 11 is in its right-hand position, the lower end of cylinder 5 is exhausted through tube 14 and exhaust port 16.

After a predetermined downward stroke of the tamper 6 to press the ball of clay 4 into the shape illustrated in Fig. 3, the cam 8 will contact the cam arm 24 to drive the cam operated spring biased double piston valve element of valve 9 to the left. When the double piston valve element of cam operated valve 9 is driven to the left, hoses and 21 are in communication with each other and are isolated from the exhaust port of valve 9. With

tubes

20 and 21 communicating with each other, high pressure fluid is conducted from conduit 10 through

pipes

21 and 20 into the right-hand end of valve 11 thereby driving the triple piston valve element of valve 11 leftwardly. An operator cannot prohibit leftward travel of the triple piston valve element of valve 11 by keeping the foot lever 7 depressed. After the foot lever 7 is depressed to initiate downward travel of the tamper 6, the left-hand end of foot lever 7 will travel beyond the lower protruding end of the piston rod of the double piston valve element of valve 17. Therefore, even though an operator retains his foot on foot lever 7 after the tamper 6 has been initiated downwardly the spring of valve 17 will be free to drive the double piston valve element of valve 17 downwardly to place the tube 19 in communication with the exhaust port of valve 17 while the tube 18 is isolated therefrom. Accordingly, when the cam or arm 8 actuates the cam operated valve 9 to initiate return travel of the tamper 6 the left-hand end of four-way valve 11 will have been exhausted via the pipe 19 and the exhaust port of valve 17. After the triple piston valve element of four-way valve 11 is driven leftwardly, the conduits 10 and 14 are in communication with each other and simultaneously isolated from the exhaust ports 15 and 16 and the conduit 13. Therefore, high pressure fluid will enter the lower end of the cylinder 5 through conduits 10 and 14 to raise the piston 23. With the triple piston valve element of valve 11 positioned at the left-hand end of the housing 12, the tube 13 is placed in communication with the exhaust port 15 while tube 13 and exhaust port 15 are each isolated from the conduits 10 and 14 and exhaust port 16. Therefore, when high pressure fluid passes into the lower end of the cylinder 5 to withdraw the tamper 6, the upper end of cylinder 5 is automatically exhausted through the tube 13 and exhaust port 15.

As better seen in Fig. 1, the valve 9 is carried in a vertically disposed slot or guideway 36. By loosening the set screws 37, the valve 9 can be moved vertically upwardly or downwardly. Since the valve 9 is vertically adjustable the stroke of the tamper 6 can be readily adjusted.

After the tamper 6 has returned to its uppermost position, the mold 3 and its tamped ball of clay can be removed from the mold holder 2 and the mold holder 2 can be reloaded with another mold and ball of clay for another identical tamping operation. The left-hand end of foot lever 7 comprises two levers capable of buckling with respect to each other. When the operator removes his foot from foot lever 7 the spring 25 of foot lever 7 will cause the left-hand end of foot lever 7 to buckle and pass beneath the valve 17 whereupon another reciprocating cycle of the tamper 6 can be initiated. After the two levers of the left-hand end of foot lever 7 have buckled with respect to each other and passed beneath the valve 17 a spring 26 will straighten said buckled levers.

Referring now to Fig. 4, it will be seen that the clay spreading tool or instrument 6 preferably comprises a solid steel bowl-shaped mallet, plunger, or tamper head member 27 having a rounded or curved convex underside. The tamper head member 27 has an outer porous flexible cloth covering 28, such as canvas or the like. Disposed between the rounded underside of tamper head member 27 and outer cloth covering 28 is an absorbent pad 29, such as felt or the like. Pad 29 is slightly spaced from the curved underside of tamper head member 27 by a shallow gas pocket or cushion 30. Stem or piston rod 22 is connected to the tamper head member 27 at the side thereof opposite to the rounded underside. Formed in the top side of tamper head member 27 is an inlet port having a T-fitting outlet ports 32 are formed in said curved or rounded underside of the tamper head member 27 and outlet ports 32 are in communication with the inlet port having T-fitting 31 connected thereto by grooves formed within the solid member 27. Connected to the T-fitting 31 are two

flexible hoses

33 and 34. The hose 33 is in communication with a high pressure gas or air source, as by connection of hose 33 to conduit 10. Hose 33 has a valve (V) disposed therein for adjusting the flow of air through hose 33 and outlet ports 32 into the gas pocket or cushion 30. The inflated gas pocket or cushion 3t flexes upon tamping and facilitates a uniform release or departure of the tamper 6 from the spread or tamped clay and eliminates sticking of the spread of tamped clay to the tamper 6.

Hose 24 is connected to a source of cooling and lubricating fluid, such as a tank or container of oil 35. Tank 35 preferably is positioned about 2 feet above the head member of tamper 6 when tamper 6 is in its raised position. When the tamper 6 travels downwardly, the increase in hydraulic head differential will cause a uniform flow or dripping of oil through the hose 34 and outlet ports 32 31 connected thereto. A plurality of' to the absorbent cloth or felt pad 29 and the outer flexible porous cloth or canvas covering 28. Pad 29 acts as a blotter soaking up this flow of oil similar to an ink stamping pad. Accordingly, the tamper 6 automatically and repetitively applies a uniform film or coating of oil to each body of spread or tamped clay. A valve (V) is inserted in flexible hose 34 for adjusting the flow of oil to pad 20.

While there has been shown and described a particular embodiment of the invention, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention, and that it is intended by the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a reciprocating clay tamping tool, a solid steel bowl-shaped tamper head having a rounded convex surface adapted to tamp clay, said tam-per head having an outer canvas cover and a felt pad disposed between said cover and rounded surface, said pad spaced from said rounded surface to define a shallow air cushion therebetween, a plurality of outlet apertures formed in said rounded surface, an inlet aperture formed in another surface of said tamper head opposite to said rounded surface, channels formed in said solid tamper head connecting all of said outlet apertures to said inlet aperture, two flexible hoses connected to said inlet aperture, one of said hoses continuously communicating with a source of compressed air to inflate said air cushion, the other of said hoses continuously communicating with a source of oil to saturate said pad and cover with oil.

2. A machine for uniformly tamping clay in a mold with a felt and canvas covered mallet and for effecting a uniform departure of said mallet from clay tamped by said mallet and for uniformly lubricating clay tamped by said mallet comprising a mold holder, an upright closed cylinder positioned directly above said mold holder, a piston in said cylinder, said mallet disposed between said cylinder and mold holder and connected to said piston by a piston rod, a source of high pressure fluid alternately connected by a four-way fluid valve and two fluid conduits to opposite ends of said cylinder, said source of high pressure fluid connected by a fluid conduit and a two-Way cam operated fluid valve to said four-way fluid valve, a cam carried by said mallet engageable with said two-way cam operated fluid valve, said mallet having at least one oil groove formed in a felt and canvas covered surface portion thereof, and said source of high fluid pressure and a source of oil in communication with said oil groove.

References Cited in the file of this patent UNITED STATES PATENTS 309,568 Schlickeysen Dec. 23, 1884 1,149,669 Mauersberger Aug. 10, 1915 1,751,049 Miller Mar. 18, 1930 1,977,699 Sebring et al Oct. 23, 1934 2,138,620 Strange Nov. 29, 1938 2,167,386 Kinnard July 25, 1939 2,190,807 Steinberger Feb. 20, 1940 2,366,297 Turner Jan. 2, 1945 2,366,780 Gelbman et al. Jan. 9, 1945 2,374,553 Miller Apr. 24, 1945 2,565,949 Clifford et al. Aug. 28, 1951 2,626,738 Nordquist Ian. 27, 1953 2,710,988 Willcox et al. llune 21, 1955 2,770,862 Miller Nov. 20, 1956