US2401227A - Hearth - Google Patents

Description

May 28, 1946. D. c. CAMPION 2,4015227 HEARTH File d Nov. 29, 1944 2 Sheets-Sheet 2 IN VEN TOR;

I Dana/0 CZ Camp/on I Patented May 28, 1946 UNITED STATES- PATENT OFFICE HEARTH Donald 0. Campion, Detroit, Mich. Application November 29, 1944, Serial No. 565,659

12 Claims.

This invention relates to a hearth and more" particularly to a hearth for a heat treating furnace.

It is anobject of this invention to produce a hearth for a heat treating furnace which is admirably adapted for a pusher type furnace wherei .1

in the stock being heat treated is pushed along the hearth,

The invention contemplates a hearth made from a high temperature alloy which can be easily assembled, disassembled and repared, which l is long lived, and which will withstand expansion and contraction due to thermal changes and temperature differences in different areas of the hearth without buckling.

These objects are achieved by fabricating the F1 hearth from a plurality of identical or similar sections or railsof a high temperature alloy and which are connected together by interlocking members which permit sufiicient longitudinal and lateral movement by the rails to take care of the incidental rails. and a dotted line showing of one of the f rails in position for disengagement,

Referring more particularly to the drawings it will be seen that my hearth comprises a plurality of interengaged rails each having an elongated body I. Body I can have an inverted V cross-section or can be fiat'in cross-section. The

rail with an inverteclv cross-section is preferable in a pusher type furnace whereas rails which are much wider than the V rails and which have a flat surface instead of a peak are preferably used as a floor in a batch type furnace where the stock is shoveled or thrown into the furnace. Bails I are made of any suitable material having high strength at high temperatures, but preferably are made from an alloy having high strength at high v temperatures such as are encountered in heat" treating furnaces.

Rail I, when assembled in the hearth, is arranged with the apex of the V up so that in cross section the rail takes the form of aninverted V Since my hearth is arranged to over-- lay or be set upon the furnace hearth 2, which is a refractory material or clay that can be easily damaged, I provide each rail of my hearth with four legs 3 which have fiat and horizontal ho tom faces 4 which rest upon the refractory hearth 2 and distribute the weight of the work over a substantially large area. If the edges of the inverted V rails were not provided with the fiat supporting legs or bearing surfaces 4, they would dig into and destroy the refractory hearth 2. It will be noted that these supporting legs 3 on opposite sides of each rail I are offset from each other.

Each rail is provided with a. plurality of integral interlocking members or fingers .5 of V section. Fingers 5 on one side of rail I are ofiset from the fingers 5 on the opposite side of the rail. Fingers 5 and legs 3 on each side of the rail are spaced a distance greater than the length of I fingers 5 and legs 3. Fingers 5 and legs 3 are approximately the same length. The spaces between fingers 5 and legs 3 are referenced 6. The length of space 6 should be greater than the length of either legs 3 or fingers 5 in an amount sufficient to care of longitudinal expansion and contraction of the rails due to temperature variations. For purposes of description and not by way of limitation, space 6 can be a quarterof an inch longer than leg 3.

In use the rails are setupon a refractory hearth 2 with the apex of the rail uppermost. Rails I are mounted in parallel rows and staggered so that the joints 1 in alternate rows are aligned and the jointsin adjacent rows are offset. The interlocking of the rails are effected by fingers 5 which interengage the underside of body I. Each finger 5 on one rail fits into a space or slot 6 in the adjacent rail between a finger 5 and a leg 3. Thus, the interlocking of fingers 5 on the underside of body I holds the rails against lateral dislacement and the interengagement of fingers 5 on the one rail in slots 6 between a finger 5 and a leg 3 on the opposite rail holds the rails from pulling apart lengthwise. The interlocking fit between the fingers of one rail and the underside of the adjacent rail is loose so as to permit longitudinal and lateral movementof the rails relative to each other caused by thermal expansion and contraction without buckling. Each leg 3 on the one rail also interengages between a leg and finger on the adjacent rail. My hearth is generally designated 8. The end sections in alternate rows of rails can be any length that permits staggering of the joints and in most cases the end sections will be one-half the length of the other rail sections. This is necessary in order to position joints 1 as above described.

To disconnect one rail from the other it is necessary to hinge or swing the one rail upwardly about the hinge provided by the interconnected fingers and legs of the adjacent rails. By swinging one rail up sufiiciently, fingers 5 simply slide or swing out of interengagement with the underside of the adjacent rail (Fig. 8).

It will be seen that the full length rail comprises two fingers 5 and two legs 3 on each longitudinal side of the rail. In fabricating the hearth, in order to offset joint ,1, a half length of rail l is used at each end of alternate rows of rails.

The rails l cooperate to form a track along which the work can he slid through a heat treating furnace, for example, adjacent rails I being interlocked cooperate to form a groove or track along which the work can be slid and the interconnecting fingers 5 and legs 3 keep the hearth from separating either laterally or lengthwise of hearth members in the adjacent row, the hearth members in each row being interengaged with the members in the adjacent row so that the members in each row can move a limited distance relatively to each other and relative to the members in the adjacent row without buckling the hearth where the movement is such as is occasioned by expansion and contraction caused by thermal changes.

stantially the form of an inverted V projecting downwardly and then upwardly from the other longitudinal edge of the rail and ofiset from the said support leg, the said support leg being adapted for interengagement with the underside of an adjacent rail of substantially the same form and the support leg being adapted to support the rail and to rest under and support an adjacent rail of substantially the same, form as the rail herein claimed.

7. A hearth member comprising a rail in substantially the form of an inverted V having at least one support leg projecting downwardly and then outwardly in a substantially horizontal plane from opposite longitudinal edges of the rail, the leg on the one side being spaced longitudinally from the leg on the other side of the rail, and at least one locking finger projecting downwardly and then upwardly from the opposite longitudinal edges of the rail, the locking finger on the one side being spaced longitudinally from the locking finger on the other side of the rail, the locking finger and support leg on each side of the rail being spaced from each other a distance sufficient to accommodate therebetween the locking finger and support leg of a rail of similar shape.

8. A hearth member comprising a rail having a cross section substantially in the form of an inverted V, said rail having on each side a sup- 2. A hearth comprising in combination a plu- 7 j rality of parallel rows of hearth members,'each hearth member having substantially the form of an inverted V, the members of each row being in substantial longitudinal alignment and offset longitudinally with respect to the hearth mem 7 bers in the adjacent row, the hearth members in each rowhaving fingers which underlie and interengage the undersides of the hearth members in the adjacent row when the adjacent hearth members are in substantially the same plane whereby the hearth members can be disengaged byhinging the hearth members in the one row upwardly aboutthe adjacent lower edge of the hearth members in an adjacent row.

3. The combination as set forth in claim 2 wherein the hearth members are provided along 'move longitudinally only a limitedrdistanc e.

4. A rail for a hearth comprising abody portion in, the form of an inverted V having a leg projecting downwardly and outwardly from one longitudinal edge of the rail, and a locking finger projecting downwardly and then upwardly from the oppositeedge of the rail.

5. The combinationfas set forth in claim 4 wherein the locking finger and the supporting leg are ofiset from each other lengthwise of the 'rail.

6. A rail for a hearth comprising a body portion in the form of an inverted V having a leg projecting downwardly and outwardly in a substantially horizontal plane from one longitudinal edge of the rail, and a locking finger in subport leg projecting downwardly and then outwardly in a substantially horizontal plane from' the lower edge of the rail, and a locking finger projecting downwardly and then upwardly from the lower edge of the. rail, the locking finger and support leg on one side of the rail being offset from the locking finger and support leg on the opposite side of the rail, the locking finger and support leg on each side of the rail being spaced lengthwise of the rail a distance slightly greater than the length of the locking finger or leg whereby two of said rails are adapted to be interengaged by inserting the locking fingers and support legs of one rail in the spaces between the locking fingers and support legs of the other rail so that the rails can move a limited distance longitudinally of each other such as is occasioned by expansion and contraction due to temperature changes without binding.

9. A hearth member comprising a rail having on each side a support leg projecting downwardly and then outwardly in a substantially horizontal planefrom the lower edge of the rail, and a locking finger projecting downwardly and then upwardly from the lower edge of the rail. the locking finger and support leg on one side of the rail being ofiset from the locking finger and support leg on the opposite side of the rail, the locking finger and support leg on each side of the rail beingspaced lengthwise of the rail adistance slightly greater than the length of the looking finger or leg whereby two of said rails are adapted to be interengaged by inserting the locking fingers and support legs of one rail in the spaces between the locking fingers and support legs of the other rail so that the rails can move a limited distance longitudinally of each other such as is occasioned by expansion and contraction due to temperature changes without binding.

10. A hearth comprising in combination a plurality of parallel rows of hearth members, the members of each row being in substantial longitudinal alignment anad offset longitudinally with respect to the hearth members in the adjacent 3:} row, the hearth member in each row having fingers which underlie and interengage the undersides of the hearth members in the adjacent row when the adjacent hearth members are in substantially the same plane whereby the hearth members can be disengaged by hinging the hearth members in the one row upwardly about the adjacent lower edge of the hearth members in an adjacent row, the hearth members being provided along their lower edges with support legs spaced from the locking fingers whereby a support leg of one hearth member will fit beneath the adjacent edge of a hearth member in an adjacent row and between a locking finger and a support leg of such hearth member in an adjacent row whereby the locking fingers and support legs of

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