US3064961A

US3064961A - Pallet for sintering machines

Info

Publication number: US3064961A
Application number: US139724A
Authority: US
Inventors: Victor F Koontz
Original assignee: Dravo Corp
Current assignee: Dravo Corp
Priority date: 1961-09-21
Filing date: 1961-09-21
Publication date: 1962-11-20
Anticipated expiration: 1979-11-20

Description

Nov. 20, 1962 v. F. KOONTZ PALLET FOR SINTERING MACHINES eat 2 3 Sheets-Sh INVENTOR.

VICTOR F. KOONTZ Filed Sept. 21, 1961 Fig.2.

his ATTORNEYS 1962 v. F. KOONTZ 3,064,961

PALLET FOR SINTERING MACHINES Filed Sept. 21, 1961 3 Sheets-Sheet 3 INVENTOR. VICTOR F. KOONTZ BY M his ATTORNEYS United States Patent 3,064,96l PALLET FOR SINTERENG MA-QHENELl Victor F. Koontz, Coraopolis, Pa, assignor to Dravo Corporation, Pittsburgh, Pa, a corporation of Pennsylvania Filed Sept. 21, rear, Ser. No. 139,724 13 Claims. (Cl. Zed-21) This invention relates to apparatus for sintering of ore or other materials or the heat-hardening of pellets, and is for a pallet for use in such apparatus.

It is well-known in the art to sinter ore or heat-harden pellets and to make cement clinker by loading loose material or preformed pellets into the trays or pallets of sintering machines and the material so loaded is conveyed through various heating or burning and cooling zones. The machines, often referred to as Dwight-Lloyd types of machines, generally have a horizontal track between the rails of which are located a series of wind-boxes con nected either to a suction fan or blower, depending upon Whether there is a down draft of combustion gases or an up draft of cooling air. A series of separate pallets are placed in succession onto one end of this trackway with the pallets in abutting relation so that as each pallet is added to said end, all of the pallets are pushed along toward the opposite end, moving in succession over the series of wind-boxes. At the discharge end of the horizontal track, each pallet in turn is tipped to dump its charge, and lowered onto a return track to then move back to the loading end of the machine, and again elevated to the beginning of the line on the horizontal track.

At the entering end of the horizontal track the pallets are loaded with a charge and they may pass under one or a succession of hoods located over the tracks, and to which hot air, flame, burning gases or combinations thereof may be supplied, or in which suction is maintained to move gases upwardly through the pallets and the charge which they contain.

Usually the charge in the pallets contains fuel or oxidizable materials so that as air or flames are drawn from the hood above to a wind-box below, combustion or an exothermic reaction takes place in some areas of travel, while at another location cold air may be blown upwardly through the pallets, or the charge may be heated to incandescence from flames being drawn downwardly through it. At any rate the charge, and the pallets, the charge-supporting bottoms of which comprise grate bars, become highly heated. They are sometimes cooled by cooling air being forced upwardly through the charge, and are further cooled as they are emptied and move through the return part of their cycle.

As a result of this drastic heating and cooling, the pallets, which are of heavy metal, become warped and weakened. As they become increasingly warped, it becomes more difiicult to maintain the seals between them and the wind-boxes. The replacement of pallets is therefore a costly factor in the operation of sintering apparatus of this type.

One major reason for the warping of the pallets arises from the fact that it is difficult in a heavy structure of this kind to relieve thermal stresses lengthwise of the pallets. Another cause of warping arises from the unequal vertical heating or thermal gradient in a vertical direction, the grates immediately under the charge being heated more drastically than the structure below this level.

The present invention has for its principal object to provide a pallet of improved construction, which will be longer lived, and is less subject to destructive warpage.

A further object of this invention is to provide a pallet in which the grate-supporting bars are separate from the main structural members of the pallet, and the main structural members are at a level where the heat is less intense.

A further object of the invention is to provide a pallet in which the grate-supporting bars are in short lengths or sections, each free to expand and contract without transmitting any stresses to the main structural members.

A further object of the invention is to provide a pallet in which all structural sections of substantial vertical depth are fabricated from parts which are designed to sulfer minimum warpage due to a temperature gradient from top to bottom, and are composite structures, while continuous elements extending the length of the pallet are of shallow vertical depth, so that they are little afiected by any temperature gradient from top to bottom.

A further object of the invention is to provide a pallet which is fabricated from metal plates and bars with only selected parts being cast, as distinguished from integral castings heretofore generally provided.

These and other objects and advantages are secured by the invention as will be more fully apparent to those skilled in the art from the following description, in conjunction with the accompanying drawings. In the drawmgs:

FIG. 1 is a perspective view in transverse section showing a portion of one end of a pallet embodying my invention;

FIG. 2 is a top plan view of a portion of the pallet shown in PEG. 1 with the end section removed;

FIG. 3 is a longitudinal section in the plane of line IIIIII of FIG. 2;

FIG. 4 is a side elevation of one section of the grate bar-supporting assembly removed from the pallet;

FIG. 5 is an end view of the assembly shown in FIG. 4 for a grate bar support intermediate to the sides of the pallet;

FIG. 6 is a similar view of a section of the grate bar support for the sides of the pallet;

FIG. 7 is a fragmentary transverse section in the plane of line VII-VII of FIG. 2;

FIG. 8 is a transverse fragmentary section of the end assembly of the pallet, the view being in approximately the plane of line VlII-VIII of FIG. 1;

FIG. 9 shows a modified grate-supporting bar section, the view being a transverse vertical section through the bar and its complementary filler plate; and

FIG. 10 is a view similar to FIG. 8 showing in longitudinal section the pallet assembly utilizing the modification of FIG. 9, line X-X on FIG. 9 indicating the plane of the section.

The general construction of the pallet may be best seen in FIG. 1, in which 2 designates an end casting which is separate from the rest of the pallet, and which is bolted thereto, as best seen in FIG. 8. It is this portion of the casting that carries the usual seals as indicated, for example, by the channel 3 at the bottom of the casting 2, and it is this end member which carries the rollers (not shown) that support the pallet on the tracks along which it moves.

According to the present invention there is an end plate member 4 at each end of the pallet which butts against the end casting 2, and which is fabricated from two metal plates in tace-to-face relation. The end plate member 4 at one end of the pallet is connected to a corresponding plate at the other end of the pallet by a plurality of heavy bars 5. These rods or bars are preferably of solid section, although they need not be, and they are preferably circular in section, although this is not necessary. They are, however, preferably of relatively small section in a vertical direction. These bars 5 are spaced one from another and provide the rigid structure connecting the two ends of the pallet. The ends of the bars are welded to the plates 4 against which they abut,

As shown in FIGS. 2 and 8, each end plate 4 is faced against the end casting 2, and is bolted thereto. The ends of the continuous bars 5 are cut away or fiattened at two sides as indicated at 5a in FIG. 2 where this is necessary to give clearance for the entry of the bolts through the holes in the end plates.

At intervals along the bars 5 between the end plates are transverse plates 6 best shown in FIG. 2, these having openings therethrough through which the rods 5 pass.

The plates 6 have welded or otherwise aflixed to each face thereof pairs of vertical cleats 7 of generally rightangle section with one leg secured to the plate 6- and one leg or flange projecting outwardly from the plane of the plate 6, the cleats of a pair being spaced from each other as indicated at d. The cleats are provided with a vertical series of holes 9 therethrough in that flange of the cleat which is normal to the plane of the plate 6. These pairs of cleats are located centrally between each two rods 5, and the corresponding pairs of cleats are in longitudinal alignment lengthwise of the pallet. At the outermost end of each plate 6 there is a single such cleat 10, and there is a confronting vertical strip 11 welded to the end of the plate 6 and spaced from the member 19 the space being designated 12 in FIG. 2.

On the face of the end plate 4 against which the ends of the rods 5 abut, and to which the rods are Welded, there are matching pairs of similar cleats also designated 7 with spaces 8 therebetween, and at the ends there are single cleats 1t) and vertical strips 11 like those on the plates 6. There is a space 12 between the cleats 1t) and 11 on these end plates.

Lengthwise of the pallet the spaces 8 are all in alignment as are the cleats themselves, and the spaces 12 are all in alignment.

Referring particularly to FIG. 4, there is shown a grate bar-supporting member designated generally as 15, which may be fabricated from metal plate, and one form of which has a top strip 16 that is welded to the top edge of a vertical plate 17 forming a generally T-shaped section with the strip 16 projecting each side of the plane of the plate 17. These members 15 have depending leg portions 18 in which are horizontally-elongated bolt holes 19, and between the legs 18 the plate is cut away so that the member 15 as viewed in FIG. 4 is somewhat of an arch shape. These members 15, as best shown in FIG. 1, have the end legs thereof fitted into the spaces 8 between the pairs of cleats 7, and bolts passing through the holes 9 and through the horizontally-elongated bolt holes 19 serve to connect the members 15 with the cross plates and hold them at the proper vertical elevation. Along each side of the pallet there is a similar row of grate-supporting members designated generally as 15a which are in all respects similar to the members 15, except that the top flange or strip 16a extends inwardly only toward the center line of the pallet, and does not project outwardly to each side of the plane of the main plate 17. In other words, while the tops of the members 15 are T-shaped in section, the tops of the members 15a are of an inverted L section. The members 15a are held in place between the cleats and 11 by means of bolts, the same as the members are held in place.

The individual grate bars are shown in FIG. 1 and they are of the general construction commonly used in sintering pallets. They comprise a bar 20 which is generally flat on top, and which is deeper at each end than it is at the center, and each end is bifurcated as indicated at 21, so as to slidably lit the

flanges

16 or 16a, as the case may be, of the grate bar-supporting

members

15 or 15a, the bars thus resting on the flanges of the

members

15 and 15a. The top flange-forming strip 16 on member 15 is wide enough so as to accommodate the ends of two sets of bars in end-to-end relation. The outside members 15a of course have to engage only the ends of one set of bars, and for this reason the strips 16a are narrower and project only inwardly from the plane of plate 15a.

As these pallets travel along in the sintering machine they move from a position over one wind-box to a position over another. If the

members

15 and 15a were not otherwise complemented with end plates to close the archway between depending legs 18, air or gases could travel freely through the pallets and defeat the purpose of the separate wind-boxes of the machine. Therefore, each grate-supporting member, as shown in FIG. 4, has a complementary tiller plate 22 having end portions 22a which are received in the spaces between the cleats the same as are the ends of the grate-supporting members themselves, and the plates 22 have wide central portions 22b which substantially close the archway between the legs 18 of the grate-supporting members. The members 22 have elongated bolt holes 23 therethrough similar to the bolt holes 19, and in vertical alignment therewith, and the lowermost bolt passing through a hole 9 in any one of the cleats passes through an opening 23 in one of these complementary arch-closing or filler pieces.

It will thus be seen that the pallet has main load-bearing members or tie bars 5 of short vertical height or depth, and spaced well below the tops of the grate bars, and the only direct heat-conductng path from the

gratesupporting bar members

15 and 15a to the rods 5 is through the relatively thin transverse plates 6. Because of the rods or bars 5 being of solid section, there is a good heat-conducting path from top to bottom thereof, and because of the rods being of relatively small diameter, particularly in a vertical direction, there is an insignificant heat gradient between the top and bottom surfaces of the rods, wherefore they tend to expand and contract quite uniformly. In pallets as heretofore generally constructed, the grate bars have been carried on wide, flanged, deep sections, the top flanges of which are close to the heat of the charge in the pallets, and the lower flanges of which are several inches removed from the intense heat of the charge, so that there was a considerable temperature gradient vertically, and the unequal stresses developed a permanent deformation that increased as the pallet was used, to a point where replacement was necessary.

In the present invention the grate bars are carried on the short members or

sections

15 and 15a, which in turn transmit the weight of the load to the main loadcarrying members 5 through the cleats and transverse plates 6. Moreover, the grate-supporting sections are spaced and mounted so as to isolate expansion and contraction effects from the bars or rods 5 which carry the main bending stresses and are relatively little subjected to differential heating and cooling because of their shape and mass.

The grate-supporting

members

15 and 15a are each of relatively short length so that the thermal expansion in any one of them is relatively small, and there is not the cumulative effect of expansion in these short sections independently supported, which there is in a continuous long section as employed in pallets as heretofore constructed. The elongated bolt holes 19 in the legs 18 of the grate bar-carrying sections permit independent longitudinal expansion and contraction of each individual support, and because of the arch form of the members 15 there is no continuous deep web to expand unevenly. The complementary plates 22 can expand and contract independently of the members 15 into which they are fitted, but for all practical purposes in sealing oif the short-circuiting of the air flow, they function the same as continuous deep Webs of the structural sections of conventional pallets.

The end castings 2 are attached to the end plates 4 by bolts 25 passing through the end plate assemblies 4 and through the vertical web of the end casting as shown in FIG. 8. As previously noted, the flattening of the ends of the

rods

5 and 5a is to afford access to the heads of these bolts which are designated 25. The end casting may have a separate upwardly-extending end wall-forming piece 26 bolted thereto. The pallet is the same at each end, so that the drawings illustrate the structure at only one end. The basic structure comprising the end members 4, the bars 5 and the cleats, is symmetrical about its medial plane so that, should it be desired, the grate-supporting bars and filter plates may be removed, the structure turned over, and the parts so removed then replaced on the second side, thus providing a reversible pallet.

In the modification shown in FIGS. 9 and 10, the structure of the pallet is the same as that disclosed in the previous figures, with the exception that the cleats for attaching the grate bar-supporting sections to the members 6 are carried on the grate bar-supporting sections instead of on the plates 6. Also, the cleats for holding the filer members are on these members instead of on the transverse supporting members 6.

In these two figures, only so much of the entire structure as is necessary to describe the modification is shown. The grate bar-supporting section is designated generally as 30 and is provided with a top flange 31. The grate bar-supporting sections would have the flanges 31 arranged either as shown in FIG. 5 or FIG. 6, depending on whether the sections were used along the outsides of the pallet or intermediate to the sides. 33 indicates the separate filler piece corresponding to the member 22 of the structure previously described. The transverse supporting member of the pallet structure, corresponding to the member 6 is designated 34.

According to the modifications here shown, the ends of grate bar section 30 are provided with laterally-extending cleats or pads 35 through which are holes 36. These pads face against the member 34. The holes 36 register with holes of the same diameter in the cross members 34. A sleeve 37 passes through the registering holes. A bolt 38 passes through the sleeve, and a nut 39 on each bolt is tightened to secure the parts together. The sleeve 37 is slightly longer than the combined thickness of the several metal sections through which it passes, so that when the nut is tightened on the bolt it will be limited by contact with the ends of the sleeve, and cannot bind against the faces of the pads 35. The grate bar-supporting sections are thus supported in the proper position, but in a manner which provides sufficient clearance to allow each grate bar-supporting section to expand and contract independently of the others. In like manner the extension 40 at the bottom of the plate 33 is provided with similar pads 41 that project laterally from the ends of the plate. These pads are provided with holes that register with holes in the cross member 34, and there is a sleeve 41 corresponding to the sleeve 37 and similar bolts 42 with nuts 43 are provided so as to secure the separate plates 33 in position on the cross members, but allow also for the expansion and contraction.

In each of the structures as above pointed out, main load-carrying members are at a level Well below the level of the grates and are positioned between the grate-supporting bars and are not a contiguous part of the gratesupporting bars. Their section is such that there is little temperature gradient between the top surface and the bottom surface of these rods or bars, and there is no good heat-conducting path from the grate bars to the rods. The tie rods 5 are of substantially smaller section in a horizontal direction than the distance between the sectional grate-supporting bar assemblies, so that there is adequate space for the flow of air or gases through the spaces between adjacent grate bar-supporting assemblies. By making the grate-supporting bars in short lengths, each can expand and contract a slight distance without afiecting the overa.l length of the grate-supporting assembly, and conditions tending to produce warpage are thereby substantially alleviated.

It will also be noted that the vertical webs of the gratesupporting bars are cut away or notched inwardly at the ends so that the tops may overhang the transverse supporting plates or end plates with only a slight gap between the confronting ends of the grate-supporting bars or between the endmost bars and the ends of the pallet. The pallet as thus constructed has a plurality of parallel gratesupporting bar assemblies, each comprised of sections in confronting end-to-end relation with slight spaces between section ends suflicient to allow each section to expand lengthwise independently of the other sections, and each section is supported in the structure in a manner that such expansion introduces no stress into the main framework of the pallet.

While I have shown and described certain embodiments of my invention, it will be understood that this is by way of illustration, and that various changes and modifications in details of construction may be made within the contemplation of my invention and under the scope of the following claims.

I claim:

1. A pallet for sintering machines and the like comprising a pair of spaced parallel end members, a series of parallel spaced grate bar-supporting assemblies extending transversely to the end members between the two end members, parallel tie bars connecting the end members, the tie bars being staggered between the grate barsupporting assemblies, each grate bar-supporting assembly comprising a series of separate sections in end-to-end relation with confronting ends spaced sufliciently to permit independent lengthwise expansion thereof, transverse plates on the tie bars extending between the ends of the sections of the grate bar-supporting sections, and means on said sections and the transverse plates through which aligned sections are connected with each other for independent expansion and contraction, the tops of said grate bar-supporting sections extending to a level above the tops of the tie bars.

2. A pallet for sintering machines and the like comprising a pair of spaced parallel end members, a series of parallel spaced grate bar-supporting assemblies extending transversely to the end members between the two end members, parallel tie bars connecting the end members, the tie bars being staggered between the grate bar-supporting assemblies, each grate bar-supporting assembly comprising a series of separate sections in. end-to-end relation with confronting ends spaced sufliciently to permit independent lengthwise expansion thereof, transverse plates on the tie bars extending between the ends of the sections of the grate bar-supporting sections, and means on the sections and the transverse plates through which aligned sections are connected with each other for independent expansion and contraction, the tops of said sections extending to a level above the tops of the tie bars, the tops of said sections of the grate-supporting bar assemblies being flanged, and grate bars in side-by-side relation spanning the space between each pair of grate barsupporting assemblies, the grate bars having end portions slidably fitted over the flanges of said sections.

3. A pallet for sintering machines and the like comprising a pair of spaced parallel end members, a series of parallel tie bars connecting the end members, a series of parallel spaced grate bar-supporting assemblies extending transversely to the end members between the two end members, the tie bars being staggered between the grater bar-supporting assemblies, each grate bar-supporting assembly comprising a series of separate sections in slightly spaced end-to-end relation, transverse plates on the tie bars extending between the ends of the sections of the grate bar-supporting assemblies, and means on the sections and the transverse plates through which aligned sections of each assembly are connected with each other for independent expansion and contraction, the tops of said sections extending to a level above the tops of the tie bars, the tops of the grate-supporting bar assembly sections being flanged, the ends of the sections overhanging the transverse plates.

4. A pallet for sintering machines and the like comprising a pair of spaced parallel end members, a series of parallel tie bars connecting the end members, a series of parallel spaced grate bar-supporting assemblies extending transversely to the end members between the two end members, the tie bars being staggered between the grate bar-supporting assemblies, each grate bar-supporting assembly comprising a series of separate sections in slightly spaced end-to-end relation, transverse plates on the tie bars extending between the ends of the sections of the grate bar-supporting assemblies, means on the scetions and the transverse plates through which aligned connections of each assembly are connected with each other for independent expansion and contraction, the tops of said sections extending to a level above the tops of the tie bars, said means on the sections and transverse plates through which aligned sections are connected comprising cleats on the transverse plates which overlap the ends of the grate sections, the sections of the grate barsupporting assemblies having horizontally-elongated holes through the ends thereof, and fasteners passing through the cleats and said horizontally-elongated holes.

5. A pallet for sintering machines and the like comprising a pair of spaced parallel end members, a series of paralled tie bars connecting the end members, a series of parallel spaced grate bar-supporting assemblies extending transversely to the end members between the two end members, the tie bars being staggered between the grate bar-supporting assemblies, each grate bar-supporting assembly comprising a series of separate sections in slightly spaced end-to-end relation,'transverse plates on the tie bars extending between the ends of the sections of the grate bar-supporting assemblies, means on the sections and the transverse plates through which aligned sections are connected with each other for independent expansion and contraction, the tops of said sections extending to a level above the tops of the tie bars, the tops of said extensions having confronting flanges, and grate bars with bifurcated ends engaging the flanges of sections of adjacent grate bar-supporting assemblies and spanning the space crosswise of the pallet from the grate bar-supporting section of one assembly to the corresponding sections of an adjacent assembly at a level spaced above the tie bars.

6. A pallet for sintering machines and the like as defined in claim 1 wherein the ends of those sections of the grate bar-supporting assemblies that terminate at the end members are attached to said end members in the same manner that the sections of the assemblies are attached to said transverse plates.

7. A pallet for sintering machines and the like as defined in claim 1 wherein the ends of those sections of the grate bar-supporting assemblies that terminate at the end members are attached to said end members in the same manner that the sections of the assemblies are attached to said transverse plates, the tie bars passing through said transverse plates.

8. A pallet for sintering machines and the like as defined in claim 1 wherein the sections of the grate bar-supporting assemblies are of arch form with each end thereof comprising a downwardly-extending leg, and a separate filler plate closing the space under the arch between the legs, and means for securing the filler plates in place.

9. A pallet for sintering machines and the like comprising a pair of spaced parallel end members, a series of parallel tie bars connecting the end members, a series of parallel spaced grate bar-supporting assemblies extending transversely to the end members between the two end members, the tie bars being staggered between the grate bar-supporting assemblies, each grate bar-supporting assembly comprising a series of separate sections in slightly spaced end-to-end relation, transverse plates on the tie bars extending between the ends of the sections of the grate bar-supporting assemblies, means on the sections and the transverse plates through which aligned sections o are connected to each other for independent expansion and contraction, the tops of said sections extending to a level above the tops of the tie bars, said last-named means comprising cleats on the transverse plates, the sections of the grate-bar-supporting assemblies having horizontallyelongated holes therethrough, and fasteners passing through the cleats and said elongated holes, said sections of arch form which depending ends and an open central area, and a complementary filler plate filling said open central area of each section, the filler plates having ends which extend under the ends of the section which it complements, the ends of said filler plates being attached to the cleats on the transverse plates in the same manner that the sections are attached to the cleats on said transverse plates.

10. A pallet for sintering machines and the like as defined in claim 1 wherein the tie bars are of substantially smaller vertical section than the maximum depth of the sections of the grate bar-supporting assemblies and are substantially narrower in a horizontal direction than the space between adjacent grate bar-supporting assemblies whereby there is free space for the flow of air vertically through the spaces between the grate bar-supporting assemblies around said tie bars.

11. A pallet for sintering machines and the like as defined in claim 1 wherein the tie bars are solid round rods of a diameter substantially less than the distance between adjacent grate bar-supporting assemblies.

12. A pallet for sintering and like machines comprising spaced end members, a plurality of spaced parallel tie bars connecting the end members, a plurality of parallel grate bar-supporting structures extending the length of the pallet spaced from the parallel tire bars, the gratesupporting structures comprising a plurality of separate sections in end-to-end relation with flanges at the tops thereof above the level of the spaced tie bars, means on the tie bars and end plates for supporting the ends of the said separate sections and holding the respective section of each such grate bar-supporting structure in confronting end-to-end relation with the other sections of the same structure and the ends of one section spaced from the ends of an adjoining section a distance suificient to permit each to extend lengthwise independently of the other, and a series of grate bars having bifurcated ends engaging the flanges of the next-adjacent parallel sections at a level above the tops of the tie bars.

13. A pallet for sintering and like machines comprising spaced end members, a plurality of spaced parallel tie bars connecting the end members, a plurality of parallel grate bar-supporting structures extending the length of the pallet spaced from the parallel tie bars, the grate-supporting structures comprising a plurality of separate sections in end-to end relation with flanges with the tops thereof above the level of the spaced tie bars, means on the tie bars and end plates for supporting the ends of the said separate sections and holding the respective section of each such grate bar-supporting structure in confronting end-to-end relation with the other sections of the same structure with clearance spaces between sec tions sufiicient to enable each section to expand under heat independently of the confrontingsections, a series of grate bars having bifurcated ends engaging the flanges of the next-adjacent parallel sections at a level above the tops of the tie bars, each such separate section of the grate bar-supporting structure being of arch form having leg portions at each end to which said means on the tie bars and end plates are attached, and a separate plate filling the opening through the arch of each section.

References Cited in the file of this patent UNITED STATES PATENTS 2,245,136 Shallock June 10, 1941 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No S O64 96I November 20 1962 Victor E. Koontz It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 5, line 18 for "fil er read filler column 6 llne 63,, for "grater" read grate *3 column 8 line 7 after "sections" insert being line 8 for wnich" read wi th 5 Signed and sealed this 14th day of May 1963 (SEAL) Attest:

ERNEST w. SWIDER DAVID LADD Attesting Officer Commissioner of Patents