US2710746A - Annealing tray - Google Patents

Description

P. S. MENOUGH ANNEALING TRAY June 14, 1955 5 Sheets-Sheet 5 Filed Feb. 2, 1951 lib F010 "-1 F r INVENTOR. PA /4 s- NEWOUG/vf A: 7'T0iP/VEYS Jime 14, 1955 P. s. MENOUGH ANNEALING TRAY 5 Sheets-Sheet 4 Filed Feb. 2, 1951 IN VEN TOR.v PA UL S. IVE/V006 I 2 jTTO/P/VEYS ited States ate ANNEALING TRAY Paul S. Mencugh, Rocky River, Ohio Application February 2, 1951, Serial No. 209,167

10 Claims. (Cl. 263-47) This invention relates to annealing trays and, in particular, to a tray which will not warp or disintegrate during a long life of productive service.

It is customary when heat treating certain articles to place them upon a tray, sometimes called a grid, which is then placed in a heat treating furnace where the' articles are subject to a predetermined temperature for a certain length of time. The tray is then removed from the furnace and unloaded. Frequently, it is desirable to quench the articles while above the critical temperature. To accomplish this purpose, the tray may be dumped into a quenching bath from inside of the furnace while both tray and the work which it carries are above the critical temperature. More frequently, however, both tray and work are suddenly dropped into the quenching medium which may be oil or water. If the tray is quenched with the work, certain destructive stresses are set up within the tray structure and if the design of the tray is not correct, these stresses will cause an early failure. After the tray has been heated up and cooled frequently it loses ductility. When this has occurred, severe and sudden thermal stresses will cause the tray to crack. Freguently, it will crack in half or possibly one or more corners will fall off.

The conventional tray is made of a one-piece casting, high in chromium and nickel. Such a casting has no flexibility whatever and is, of necessity, made of fairly heavy sections. Otherwise, it would not be possible to run the castings in the foundry. The destructive stresses which are set up in such a tray, particularly when it is quenched in oil or water, are accentuated by the fact that the load is supported on the center of the tray while the outside members of tray are integrally locked to the center portion. When such a tray, so loaded, is heated up or cooled in a furnace, the outside members of the tray are exposed to the heating and cooling medium much more effective than the center of the tray which is protected by the mass of the work which it supports. Consequently, the outside members of a one-piece cast tray expand and contract much more rapidly than the center portions of the tray. This sets up destructive stresses between the outer members and the center portion of the tray. This generally is one of the most prolific causes of premature failure.

Much the same criticism applies to trays which are fabricated from rolled sections. They are lighter in cross section than the one-piece casting and, to a certain degree, are more flexible. Generally, however, the fabricated tray is fashioned after the design of the one-piece casting with the separate members being held in their relative positions by means of welds. The same thermal stresses are set up in the fabricated tray due to sudden heating and cooling as outlined above for castings, and premature failure frequently occurs.

Furthermore, where trays of relatively light fabricated construction are employed, temperature differentials between the loads and parts of the trays engaging the loads,

particularly the tray grids, tend to develop to the point that destructive stresses are created in the trays.

In some cases the trays are propelled through the furnace in a row by pushing force applied to the tray nearest to the entrance end of the furnace. When the trays are of the fabricated type and the row includes several trays, the trays, if heavily loaded, tend to collapse due to the resistance to movement offered by the leading trays and the pushing force exerted by trailing trays.

Although many efforts have been made to solve these important and perplexing problems, no one has yet solved them satisfactorily to my knowledge.

The present invention aims to solve these problems and attains that objective by providing a new tray comprising heavy strong parts where strength is required and light parts where the strength requirements are less, the heavy and light parts being so associated that they will operate as a unit and yet expand and contract independently without-either exerting unduly high stresses on the other. Moreover, the light parts are protected by the heavy parts from excessive furnace heat.

One object of my invention is to provide an annealing tray which has a ratio of live load to dead load which is high as compared with conventional trays.

Another object of my invention is to provide a tray comprising a grid and a frame which may be connected for operation as a unit and either part may be replaced without damage to the other.

Another object of my invention is to provide a grid for an annealing tray in which the load bearing bars are slotted in a manner to pick up and position the tie bars.

A further objects of this invention is to overcome the common prior art difiiculty of carbon build-up in fabricated annealing tray grids resulting in the loss of grid flexibility and the development of destructive forces in the grids.

An additional object of my present invention is to provide an annealing tray grid having all the flexibility and other desirable characteristics of the sectional tie bar grids of the prior art, but being entirely free from the shortcomings of these grids and particularly their short service life under annealing conditions favoring carburizing of the metal of their parts.

Another object of my invention is to provide a tray which is capable of differential expansion in its frame and load carrying parts without any substantial lateral distortion.

Another object of my invention is to provide a tray which consists of separate parts mechanically associated with each other for operation as a unit and in which each part may individually respond to temperature variations without imposing undue stresses on the other parts.

Another object of my invention is to provide an an nealing tray which, although furnishing a substantial support for the articles, at the same time facilitates access of heat to the articles whereby the articles may be heated uniformly, at the same rate on all sides.

Still another object of this invention is to provide a tray in which destructive stresses due to sharp temperature differentials between the frame, the grid and the load cannot develop in normal use.

Another object of my invention is to provide a tray whereon the articles may be quenched directly and uniformly without warping or cracking the tray.

The present invention will be better understood by those skilled in the art from the following specification and the drawings which accompany and form a part thereof, and in which:

Fig. 1 is a top, plan view of one form of annealing tray embodying the present invention;

Fig. 2 is a transverse, sectional view taken on line 2-2 of Fig. 1;

Fig. 3 is a fragmentary, longitudinal, sectional view taken on line 3-3 of Fig. 1;

Fig. 4 is a perspective view of a modification of the tray shown in Fig. 1;

Fig. 5 is a fragmentary, top plan view of a modified form of tray embodying the present invention;

Figs. 6 and 7 are sectional views taken on line 6-6 and 7-7 of Fig. 5;

Figs. 8 and 9 are perspective views of the tie bars of Fig. 5;

Fig. 10 is a fragmentary, top plan View of a tray embodying the present invention and resembling the tray of Fig. 5;

Figs. 11 and 12 are cross-sectional views taken on lines 1]11 and 12-42 of Fig. 10;

Fig. 13 is a fragmentary, top plan view of still another modified form of the invention shown in Fig. 5;

Fig. 14 is an end elevational view of the tray shown in Fig. 13;

Fig. 15 is a side elevational view, partly in section, taken on line 151.5 of Fig. 13;

Fig. 16 is a fragmentary, top plan view of still another modified form of tray embodying the present invention, a portion of the top flange of the channel being cut away in the interest of clarity;

Fig. 17 is a transverse, cross-sectional view taken on line 1717 of Fig. 16;

Fig. 18 is a fragmentary, cross-sectional view taken on line 12-18 of Fig. 16;

Fig. 19 is a view similar to Fig. 18 taken on line line 19-19 of Fig. 16 but with the top flange of the frame channel removed;

Fig. 20 is a fragmentary, top plan view of another modified form of tray embodying the present invention;

Fig. 21 is a fragmentary, end elevational view, partly in section, taken on line 2121 of Fig. 20;

Fig. 22 is a fragmentary, side elevational view taken from line 2222 of Fig. 20;

Fig. 23 illustrates two alternate load bars of the Fig. 20 tray grid with tie bars shown in assembled relation.

The tray shown in Figs. 1 to 3 consists of a frame 1 and a rack 2. The frame 1 is T-shaped in cross section and comprises a rim 3 and a web 4 and may be fabricated by rolling a bar into such shape and then cutting away parts and joining parts. When the bar has been so cut it may be bent into substantially rectangular shape of Fig. 1 whereupon the edges 5 may be welded together as at 7 and then inwardly bent ends 8 of the rim may be brought into abutting contact with each other and secured to each other by any suitable means, for example, by means of rivets 9 with or without weld metal 10 or by welding alone. The curved edges 6 above mentioned form holes 11 at the corners v of the frame when the frame is bent as just described and these holes not only serve to lighten the frame with out decreasing its strength but also to prevent breakage of the rim due to failure of the welded joint be tween edges 5.

A frame constructed as is shown in Fig. 1 and as just described may be quite massive and will be strong enough to meet all service requirements and yet it may be fabricated in contrast to casting which was the only previously known method by which such a heavy and strong frame could be produced.

When frame 1 is to be pushed through a furnace on roller rails it may be provided with slides which are preferably welded to the lower edges of rim 3 and each of which preferably consists of a flat or plate-like portion 12 to ride on the rollers and a depending flange 1.3 to engage the sides of the rollers and maintain the frame thereon.

The grid comprises a plurality of load bars 15 having their ends notched as at 16 and having tie bar-receiving slots 17 extending along their longitudinal axis.

Webs 4 of the frame 1 project into the notches 16 in the ends of the load bars 15. Tie bars 20 each extend through aligned holes 17 in load bars 15 and have notches 21 in their edges to receive the load bars. The tie bars are provided with notches in their ends to receive the web 4 after the manner shown for the notches 11: of the load bars. If desired, locks 22 may be placed in slots 17 of the load bars 15 and secured to these bars adjacent to the tie bars 20 to prevent the latter from shifting or tilting.

in constructing the tray of Fig. 1, the bar 1 may be fabricated and cut as above described, the load bars and tie bars may be assembled with each other and then the rim may be bent about the rack with the web projecting into the end notches of the load bars and tie bars and then the various surfaces of the rim may be connected as above described.

5y reason of this construction, the tray consisting of frame 1 and grid 2 acts as a unit although these two parts may expand and contract independently and without either one imposing any undue stresses on the other part.

The tray shown in Fig. 4 comprises a frame consisting of two similar end castings 25 having pin-receiving end bifurcations 26 and two side castings 27 have pinreceiving ends 28 to fit between the bifurcations 26. Pins 29 connect the ends 26 and 27 and may be welded in place and also, if desired, to the several pin-receiving end parts to make the frame substantially rigid. The rim parts and 26 have subsiantiaiiy plane inner and outer sides, i. e., there is no inwardly extending projection like the web 4 of the tray of Fig. 1.

Load bars 30 and tie bars 31, quite like those shown in Fig. 1 and assembled in substantially the same manner, are positioned Within the frame. The load and tie bars 33 have end tenons 32 which project into corre spondingly shaped holes in the frame parts. These tenons and holes maintain the grid in the frame while permitting independent expansion and contraction of these two parts without the exertion of undue stresses by one part on the other and while the parts are acting as a unit.

In Figs. 5 to 9, inclusive, the tray shown consists of a frame In which is quite similar to frame 1 of Fig. 1, the main difference being that the ends of the frame bar are brought into abutting contact and welded together not only at the rim 3/: but also at the web 4a as indicated by weld metal 10a.

The grid of this tray comprises load bars 15a and tie bars 20a. The load bars 15:: have notches 16a in their ends as is shown in Fig. 7 to receive the web 4.4 of the frame and have a plurality of small round holes 1711 to receive the tenon-like ends 32 of tie bars 20:]. The tie bars between load bars have tenons 32 at each end as is shown in Fig. 9 while the tie bars between the frame and an adjacent load bar have a tenon at one end and a webreceiving recess 16a at the other end to receive the web of the frame. The load bars may be secured in place by weld metal 33 joining a tenon of a tie bar to the load bar through which it projects. If desired, the load bars shown in Fig. 8 may be welded to the web of the frame as indicated at 34.

The tray of Figs. 5 to 9 may be made entirely of fabricated stock and possesses the numerous advantages above described with respect to the tray of Fig. 1.

Figs. 10, 11 and 12 show a tray which is a modification of the tray shown in Figs. 5 to 9. The frame in, load bars 15a and tie bars 20 of this figure are substantially like the correspondingly numbered parts of Figs. 5 to 9. The frame of Figs. 10 to 12 additionally includes the rods 35 which extend parallel to the tie bars 260 and through a plurality of load bars 151: and are secured in place by Welds to the middle load bar. Rods 35 thus are of such length that they fit in the space separating opposing side webs 4a and they are provided for the purpose of assuring that the load bars and tie bars, i. e. the grid of this tray, will maintain its shape during handling prior to as sembly with frame in.

Figs. 13, 14 and 15 show a light-weight tray. The frame of this tray comprises the side bars 40, the end rods 41 and the corner braces 42. The side bars 40 are narrow, rolled plates with their ends bent back as is shown at 43 and extended through holes in the bar and the free end portion projects through a hole in the side bar as is indicated at 44. These rcversely bent ends afford strength and rigidity to the frame and serve as abutments against adjacent trays and as guards to keep other parts of the tray out of contact with the walls of the furnace.

The grid of the tray shown in Figs. 13 to 15 comprises load bars 15b, tie bars 281: and cross bars b. The load bars 15!) have a plurality of holes along their medial lines through which rods 41 and load bars 29b project. Preferably, the tie bars 2% and rods 35b lie closely adjacent or actually in contact with each other, as is indicated in Fig. 13. cross bars 35 outside side bars 48 to keep said cross bars in position in the tray within predetermined limits.

The corner braces 42 are rods which extend diagonally of the tray through holes in the side bars and the adjacent load bars 15b and may be welded in place if necessary.

The tray of Figs. 13 to 15 may be made wholly from fabricated light, and yet strong, parts which may be removed and replaced if desired and the frame and grid parts may expand and contract independently of each other and without imposing strong stresses upon one another.

The tray shown in Figs. 16 to 19 comprises a frame 56 which is a channel in cross section with the bottom horizontal flange 51 of the channel extending inwardly. This channel may be fabricated in a long piece and, after being cut away to form corner notches as described above in connection with Fig. 1, it may be bent into rectangular shape and the corners welded together as is indicated at 70. Combined slides and stitfeners 52. in the form of T bars have inwardly extending notches 53 to receive the opposite side flanges 51 of angle 50. These T bars 52 afford fiat surfaces to move along rollers in the furnace and have depending guards or flange-like portions 54 to maintain the tray on the rollers while being moved through the furnace. The grid comprises the load bars 15d and tie bars 20a. The load bars extend transversely of the frame, rest at their ends on the top of the lower flanges 51 and have elongated slots 17d on their medial line to receive tie bars 29d which have notches 21d extending inwardly from opposite edges to receive the load bars. The rack is loosely carried on flanges 51 of the frame and, where the top flange of the channel has been removed, as shown in Fig. 19, may be removed simply by being lifted out of the frame.

The tray of Figs. 16 to 19 may conveniently be made of any suitable alloy and possesses the many advantages of trays previously described.

Figs. 20, 21, 22 and 23 show a tray which, in some respects, resembles the tray of Figs. 13 to 15. In this case the parts are all fabricated and the bars are of approximately the sarne weight material and the corner rods are substantially alike.

The frame comprises side bars and bars 61 and corner braces 62 which extend diagonally of the frame and each projects through holes in the adjacent end and side bars. These rods may be welded at each end to the side and end bars as is indicated at 63. Additionally, plates 64 which are parallel and adjacent to side plates 61 and have holes through which rods 62 extend may be considered as constituting a part of the frame if desired.

The load bars He and the tie bars Ztle are quite like bars 15 and 20, respectively, of Fig. 1, i. e., but tie barreceiving slots 17c along the medial lines of these bars are not aligned transversely of the grid as was indicated in Washers 45 are fastened to the ends of 6 previously described modifications, particularly that of Fig. 1. On the contrary, the slots in every other load bar are aligned and the slots in alternate load bars are aligned but extend in the opposite direction so that a tie bar, when assembled with a plurality of load bars will have one side positioned close to the ends of slots 17:: in one set of load bars and the other side close to the other end of the slots in the alternate load bars. Tie bars 2% have notches 21 extending inwardly from their opposite edges to receive the load bars.

By this arrangement and location of slots the tie bars are fixed in position without requiring any securing means I such as welding so long as the load bars are held in posi- 1 tion by the frame. In other words, when the tie bars are being assembled with a plurality of these load bars, the load bars are so positioned that the slots 17 in all the bars are in alignment, then the tie bars are passed through the slots and are turned through to retain the load bars. Then the load bars are moved so that the slots are shifted to the position above described. In that position the ends of the load bars are in substantial alignment as best seen in Fig. 23.

As will have been noted, the frame and grid of this tray provide for differential expansion without either part imposing strong stresses on the other and parts may be replaced when desired. The tray of these figures, while comparatively light in weight, has a strong and comparatively rigid frame and is suitable for many types of use.

it will be understood that all the above described types of trays possess at least to a certain extent the numerous advantages specifically described above in connection with one or more of the illustrated trays.

It will also be understood that these trays may be made of various materials but for many uses metal highly resistant to high temperatures and corrosion such as chrome or chrome nickel steel may be used. For other uses aluminum may be suitable and for still other purposes other metals may be satisfactory. it is to be understood that any of the foregoing specifically illustrated and described trays may be made of any metal or metals suited to the intended purpose.

It is also to be understood that the shapes of parts illustrated in the various figures may be combined with parts shaped according to other figures. For instance, the T-shaped frame of Fig. 1 might be replaced by an angle-shaped frame, such as is shown in Fig. 19 or a channel with the top flange left off, i. e., an angle frame with the bottom horizontal angle extending inwardly. Similarly, the staggered arrangement of slots in the load bars as is shown in the grid illustrated in Figs. 20, 21, 22 and 23 may be used with any of the other trays illustrated. Also, the short tie bars of the modification shown in Figs. 5 to 12, inclusive, may be replaced by the longer tie bars of other figures and vice versa and the rods 12 of Fig. 10 may be used with any of the other illustrated trays. However, it is contemplated that when a tray is desired for some particular purpose wherein some particular features are to be present, a tray may be constructed by choosing parts from all those illustrated to give the desired effect.

Furthermore, regardless of the manner in Which the frames and grids of this invention are combined, the novel results and advantages stated above concerning elimination of stresses in the trays due to temperature differentials between the loads and the grids and frames of the trays. The heavy section metal frames hereof, in other words, serve in effect as heat shields for the grids so that the heating of the grids and loads is substantially uniform in rate. Thus in the preferred form and practice of this invention the temperatures of the load, frame and grid will not be substantially different during any heating operation.

Having thus described the present invention so that those skilled in the art may be able to gain a better understanding and practice the same, I state that what I desire to secure by Letters Patent is defined in what is claimed.

What is claimed is:

l. An annealing tray comprising a generally rectangular, shape-maintaining metal frame having side and end members and a load-supporting metal grid disposed in said frame and loosely engaged therewith, said frame and grid being expandable and contractable relative to each other with temperature changes and movable within predetermined limits independently of each other, said grid including load bars extending between and engaging said end members and a plurality of short tie bars, certain of said tie bars extending between, engaging and spacing a load bar and a frame side member, and other tie bars engaging, extending between and spacing the load bars in pairs, and said frame being at least as thick as the grid and opposing the side and end portions of the grid over substantially the full thickness of the grid.

2. A load supporting grid for an annealing tray comprising a plurality of spaced, substantially parallel, fiat load bars disposed on edge and having tie bar-receiving slots along their medial lines, said load bars being arranged with the said slots in partial alignment transversely of the grid but with the slots of adjacent load bars extending in opposite directions from their registered end portions, and a plurality of spaced, fiat, substantially parallel tie bars extending at substantially right angles to the load bars through said openings, alternate load bars bearing against opposite sides of a tie bar.

3. A load supporting grid for an annealing tray comprising a plurality of spaced, substantially parallel, flat load bars disposed on edge and having tie bar-receiving slots along their medial lines, said load bars being arranged With the said slots in partial alignment transversely of the grid but with the slots of adjacent load bars extending in opposite directions from their registered end portions, and a plurality of spaced, flat, substantially parallel tie bars extending at substantially right angles to the load bars through said openings, said tie bars having notches extending inwardly from their edges to receive the load bars in interlocking engagement, and alternate load bars bearing against opposite sides of each tie bar.

4. An annealing tray comprising a generally rectangular, shape-maintaining metal frame having an inwardlyextending, gridsupporting wall, and a load-supporting metal grid disposed in said frame and engaged therewith, said frame and grid being expandable and contractible relative to each other with temperature changes and movable within predetermined limits independently of each other, said grid comprising a plurality of fiat on-edge and parallel load bars extending between and supported by the said wall at the ends of the frame and having openings in their sides, and a plurality of flat, on-edge, relatively short tie bars extending at right angles to and disposed between said load bars, said tie oars having end portions of reduced dimension engaging opposed sides of adjacent load bars and projecting through the openings in said load bars, certain of the tie bars engaging and being supported by the said wall at the sides of the frame.

5. An annealing tray comprising a generally rectangular, shape-maintaining metal frame having an inwardly-extending, grid-supporting Wall, a load-supporting metal grid disposed in said frame and engaged therewith, and a plurality of rods carried by the grid and having end portions disposed in line with and adjacent to opposed portions of said grid-supporting wall for reinforcing engage ment with the frame, said frame and grid being expandable and contractible relative to each other with temperature changes and movable within predetermined limits independently of each other, and said grid comprising a plurality of flat, onedge and parallel load bars extending between and supported by the said walls at the ends of the frame and having openings in their sides, and a plurality of fiat, on-edge, relatively short tie bars extending at right angles to and disposed between said load bars, said tie bars having end portions of reduced dimensron engaging opposed sides of adjacent load bars and projecting through openings in the said load bars, certain of the tie bars engaging and being supported by the said walls at the sides of the frame.

6. An annealing tray comprising a generally rectangular, shape-maintaining metal frame having an inwardlyextending, grid-supporting wall, a load-supporting metal grid disposed in said frame and engaged therewith, and means carried by the grid for limiting relative motion of the grid in the frame, said frame and grid being expandable and contractible relative to each other with temperature changes and movable within predetermined limits independently of each other, said grid comprising a plurality of flat, on-edge and parallel load bars extending between and supported by the said walls at the ends of the frame and having openings in their sides, and a plurality of flat, onedge, relatively short tie bars extending at right angles to and disposed between said load bars, said tie bars having end portions of reduced dimension engaging opposed sides of adjacent load bars and projecting through openings in the said load bars, certain of the tie bars engaging and being supported by the said walls at the sides of the frame, and said grid motion limiting means including a plurality of rods welded to and extending through the load bars and having end portions disposed in line with and adjacent to said gridsupporting frame wall for engagement therewith when the grid is moved relative to the frame to a predetermined extent.

7. A load supporting grid for an annealing tray comprising a plurality of spaced, substantially parallel, flat load bars disposed on edge and having openings in their sides, a plurality of fiat and relatively short tie bars disposed on edge and extending at substantially right angles to the load bars, said tie bars each extending between and engaging adjacent load bars and having end portions of reduced dimension engaging opposing sides of adjacent load bars and projecting through said load bars, and elongated cross bars extending through registered openings in the load bars and bearing against and retaining the tie bars in assembled relation to the load bars.

8. A load supporting grid for an annealing tray comprising a plurality of spaced, substantially parallel, flat load bars disposed on edge and having openings in their sides, a plurality of fiat and relatively short tie bars disposed on edge and extending at substantially right angles to the load bars, said tic bars each extending between and loosely engaging adjacent load bars and having end portions of reduced width engaging opposing sides of adjacent load bars and projecting through said load bars, and elongated cross bars extending through registered openings in the load bars and disposed between and loosely engaging adjacent tie bars and retaining said tie bars in assembled relation to the load bars.

9. A load supporting grid for an annealing tray comprising a plurality of spaced, substantially parallel, fiat load bars disposed on edge and having openings in their sides, a plurality of fiat and relatively short tie bars disposed on edge and extending at substantially right angles to the load bars, said tie bars each extending between and engaging adjacent load bars and having end portions of reduced dimension engaging opposing sides of adjacent load bars and projecting through said load bars, elongated cross bars extending through registered openings in the load bars and bearing against and retaining the tie bars in assembled relation to the load bars and corner brace means comprising a brace bar disposed in each corner portion of the grid and extending diagonally between and firmly engaging adjacent load bars to stiffen the grid structure against forces tending to distort the grid in use.

l0. A load supporting grid for an annealing tray com- '7 prising a plurality of spaced, substantially parallel, fiat load bars disposed on edge and having tie bar-receiving slots along their medial lines, said load bars being arranged with the said slots in partial alignment transversely of the grid but with the slots of adjacent load bars extending in opposite directions from their registered end portions, a plurality of spaced, flat, substantially parallel tie bars extending at substantially right angles to the load bars through said openings, said tie bars having notches extending inwardly from their edges to receive the load bars, and corner brace means comprising a brace bar disposed in each corner portion of the grid and extending diagonally between and rigidly joining a side bar and a load bar adjacent to a corner of the grid to stiffen the grid structure against forces tending to distort the grid in use.

References Cited in the file of this patent UNITED STATES PATENTS FOREIGN PATENTS Great Britain Apr. 27, 1949

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