US2263212A - Saggar pin - Google Patents

Description

W. W. IRWIN -SAGVGAR PIN I Nov. 18, 1941.

Filed 001;. 1%, 1940 INVENTOR.

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ATTORNEYS.

Patented Nov. 18, 1941 it UNlTEDT STATES PATENT owes I SAGGAR PIN William W. Irwin, East Liverpool, Ohio, assignor to The Potters Supply Company, East Liverpool, Ohio, a corporation of Ohio Application October 16, 1940; Serial No. 361,349 4 Claims. (01. 25-453) This invention relates to saggar pins by which glaze-coated ceramic dinnerware and the like is supported in saggars while being fired to vitrify the glaze. As used herein the word saggar means any type of receptacle or rack in which ceramic ware is supported on saggar pins during firing.

The most practical type of saggar pin is one formed from ceramic material extruded through a triangular die, as such a pin has much more strength than a molded or cast pin of the same cross sectional area, and its triangular shape gives three well-defined points at each end, any one of which may be used for engaging and supporting the ware. The opening in the saggar wall which receives and supports the pin is usually inclined so that the ware will engage the pin at its upper point only and not along its upper edge.

As the ware is being fired,.the point of the pin is fused to it by the glaze which runs down the pin and forms a globular ring around it. The portion of the pins pointed end that is embedded in this vitrified'ring of glaze breaks from the body of the pin when the ware cools or when it is lifted from the saggar. This leaves a hard, jagged piece of the pin projecting from the bottom of the ware, and this piece must be chipped off and the raised ring of glaze removed as well as possible before the ware can be sold. It often requires considerable dressing to remove these marks from the ware, and in chipping off the adhering piece of pin the ware is sometimes spalled, which makes it necessary to sell the ware as a second.

It is among the objects ofthis invention to provide a saggar pin which leaves only a very small piece adhering to the fired ware,.which permits the formation of only a relatively small ring of glaze around its ware-supporting point, and which is as satisfactory and can be manufactured as cheaply as the customary extruded saggar pins used at present.

In accordance with this invention a saggar pin, having a pointed end for engaging and supporting glaze-coated ceramic ware during firing, is provided adjacent its pointed end with a recess which, by suddenly changing the contour of the pin, limits to avery short distance the distance the glaze will flow from the ware down around the pointed end portion of the pin. Preferably, this change in section or contour is formed by providing the side surfaces of the pin adjacent their lateral edges with grooves extending longiwill usually stop creeping downthe pin when it reaches the edges of the grooves nearest the ware,

and thus a smaller globule of glaze is formed which .can be removed more easily and satisfactorily.

The invention is illustrated in the accompanying drawing in which Fig. 1 is a plan viewof a. saggar in which a plurality of plates are supported by saggar pins; Fig. 2 is an enlarged fragmentary vertical section taken on the line IIII of Fig. 1; Fig. 3 is a still further enlarged fragmentary vertical section of a plate supported by a saggar pin and showing them just after firing and before the plate has broken from the pin;

Fig. 4 is a perspective View of my saggar pin;

Fig. 5 is a fragmentary view of the bottom of a plate showing a ring ofglaze around the point of a pin which has broken from the ware; and Figs. 6, 7 and 8 are end views of saggar pins made in accordance with three different embodiments of this invention.

Referring to Figs. 1 and 2 of the drawing, a refractory saggar I of well known construction contains the usual two compartments each of which is adapted to receive a plurality of dinner plates 2 or the like that previously have been coated with glaze and are to be fired in a kiln to vitrify the glaze. Each compartment of the saggar is provided in its side wall with three vertical rows, substantially 120 apart, of vertically spaced openings 3. Each opening is preferably triangular in cross section with the base of the triangle at the bottom of the opening and with the axis of the opening inclined upwardly at an angle of about 12. Inserted in each of these openings and projecting therefrom is a ceramic saggar pin 4 that is triangular in cross section. The pin preferably-is formed by extruding suitable ceramic material through a triangular die. The inner or upper ends of the pins at each level in the saggar engage and support a plate on their uppermost points.

It is a feature of this invention that only a relatively small ring of glaze forms around the adjoining end of each pin, so that the ware is easily dressed and is not injured in removing the ring of glaze and the point of the pin adhering to it. Accordingly, close to the ware thepointed end portion of the pin is reduced in cross section to interrupt the smooth surface of the pin and thereby provide edges beyond which the molten glaze has little tendency to flow. For this purpose the pin is preferably provided with a plurality of grooves 5 extending from end to end tudinally from end to end of the pin. The glaze along its side surfaces adjacent their lateral edges. These grooves may be of various shapes in cross section, as shown in Figs. 6, 7 and 8, and are easily formed at no increase in manufacturing cost by providing the die through which the pin is extruded with projections of the desired size and shape. When the ware is fired and the glaze melts, it tends to run down onto the pin and to thereby form a ring 6, as shown in Figs. 3 and 5, but the distance this ring extends down on the pin is generally limited by the upper edges of grooves 5 because the glaze seldom changes its direction of flow in order to pass around those edges and into the grooves. Consequently, only a small globular ring of glaze forms around the end of the pin, and this blemish can be removed much more easily and satisfactorily than a large ring of glaze. With only a small, thin ring of glaze fusing the saggar pin to the ware, only a very small piece of the pin (Fig. 5) breaks from the ware after the glaze has solidified. In chipping this point of the saggar pin from the ware there is little danger of spalling the ware. If any of the glaze should happen to flow into the grooves 5, it will run down them and therefore not increase the size of the ring forming around the point of the pin. The grooves also weaken the point of the pin so that the portion of the pin that adheres to the ware will not break from the body of the pin at a point below the grooves.

According to the provisions of the patent statutes; I have explained the principle and construction of my invention and have illustrated and described What I now consider to represent its best embodiments. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

for firing, the side surfaces of said pin being:

provided adjacent their lateral edges with grooves extending longitudinally from end to end of the pin.

3. An elongated saggar pin having two side surfaces meeting along an edge extending lengthwise of the pin, said edge at at least one end thereof being adapted to engage and support glaze-coated ceramic ware in a saggar for firing, and each of said two side surfaces being provided closely adjacent said edge with a groove extending lengthwise of the pin from the waresupporting end thereof.

4. An extruded saggar pin of substantially uniform cross section from end to end and having a sharp edge extending lengthwise thereof throughout its length to form a ware-supporting corner at each end of the pin, the surface of the pin being provided on both sides of said edge and closely adjacent thereto with grooves extending from end to end of the pin parallel to said edge.

WILLIAM W. IRWIN.

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