US1899539A - Grate bar - Google Patents

Description

1933- J. s. THOMPSON GRATE BAR Filed June 25, 1931 INVE OR ATTORNEYS Patented Feb. 28, 1933 u'.uEs s 'rnomrson, or NEW ROCHELLE, conromrron, or CLEVELAND, OHIO,

r OFFICE j NEW YORK, ASSIGNOR TO FIREBAB A CORPORATION OF DELAWARE ena'rn BAR Application filed June 25,

This invention relates to grate bars of the type commonly employed for heavy duty puroses in locomotives, boiler furnaces, and the like, and is concerned more particularly with a novel grate bar which is of extremely light weight, low cost, and long life. The advantages and benefits derived from the use of the new bar are in part attributable to its general configuration and inpart to the 19 material of which itis made and the method of making it. In some respects, the new grate bar resembles that invented by Buckley and covered in his co-pending application for j patent, Serial N 0. 338,852, filed February 8, 1929, but differs therefrom and constitutes an improvement thereon, as will be presently pointed out in detail.

. The grate bar disclosed by Buckley in the application referred to, includes a carrier 20 and a plurality of fuel-supporting units or fingers removably mounted on the carrier. The grate bar is preferably of the rocklng type, the carrier having trunnions for the purpose, and the units are mounted transversely on the carrier, so that they are sometimes referred to as cross-bars. These units are supported by the carrier so that they have a limited freedom of angular movement about the longitudinal axis of the carrier but 30 are provided with means which in one form of the device lock the units to the carrier when the limit of angular movement is reached. In this form the units are freely removable from the carrier by being lifted vertically therefrom but cannot be thrown free during rocking because the locking means are effective to prevent such displacement. In anotherform of the Buckley bar, the locking tical movement, and the units are removable only at the ends of the carrier which has a special shape at those points to serve the desired purpose.

In the Buckley bar, each unit has spaced vertical lugs on its faces defining air channels for upward flow of air to the fuel and its top is provided with a multiplicity of small fuelsupportng projections around which the air from the passages may flow. The air keeps the projections cool and prevents their being means prevent removal of the units by a ver- 1931. Serial No. 546,778.

burned out, and by reason of the excellent air distribution to the fuel, remarkable com-Y bustion results have beenobtained. Also, the free angular movement of the units on the carrier has-been found to provide a self-cleaning action,particularly when the bars are used in a locomotive wherethe structureis subjected to jars and shocks. v

'In practice, the Buckley bar is commonly made of cast metal, and it has a substantial 00 weight. While this is not objectionable in most instances, modern locomotives tend to become bigger and heavier as timegoes on, so that the weightof the grates is, a serious item, and some railroad officials have thought the requirements of low weight of grates are more important than the combustion and maintenance advantages afforded by the Buckley bar.

The present invention is accordingly directed to the provision of a grate bar which may afford the numerous advantages and benefits of. the Buckley bar but which is much lighter in weight, and lower in cost. The new bar includes a carrier'which may be of cast iron, cast steel, .or any other desired material, and fuel-supporting units thereon which are hollow and produced from a single sheet metal blank by suitable stamping operations. By reason of the fact that each unit is of a single piece of sheet metal of light gauge and is hollow, provision ismade to stiffen and strengthen the unit to resist stresses which tend to bend and distort the unit under load. Also, since the unit is of one piece and subjected to different tempera-' tures at dilferent places, it is so constructed as to absorb expansion stresses which would produce distortion.

For a better understanding of the invention, reference may be had to the accompanying drawing, in which I Fig. 1 is a view showing the carrier in cross-section and one form of unit in elevation; r y I Fig. 2 is a top plan view of a unit;

Fig. 3 is a sectional view on the line 3-3 of Fig. 1;

Fig. 4 is fragmentary side elevation of a carrier showing a pair of units thereon;

Fig. is a view in elevation of a unit of modified construction;

Fig. 6 is a sectional view on the line 6-6 of Fig. 5;

Fig. '7' is a fragmentary elevational view of another form of unit, and

Fig. 8 is a sectional view on the line 88 of Fig. 7.

The new grate bar in the form illustrated includes a carrier comprising a web 10 with an upright guiding and centering flange 11 extending from its top surface and a reinforcing fin 12 extending downwardly from its under surface. In the construction shown, the carrier is of the rocking type and it is provided with arms 13 at its ends having trunnions 14 projecting therefrom. The carrier is provided at a suitable location underneath with an arm 15 to which a shaker rod may be attached so that all of the grate bars in a grate may be rocked in unison.

'Mounted on the carrier are fuel-supporting units, one of which is generally designated 16. a Each unit is made of a single blank of sheet metal of relatively light gauge and the unit hasa' solid or continuous top, generally designated 16, and separate side walls 17 which have flanged edges 18 meeting in a seam 19 in the central plane of the unit.

I The edges of the seam are secured together by suitable welding operations. The seam 19 extends throughout all the edges of the unit below the top and at either end of the top the flanges 18 are turned in and fit tightly against the end edge20 of the top, being welded to that edge. As illustrated in Fig.

2, the flanges 18 formed on the side walls 17 are given a bulging shape as indicated at 21, this bulge strengthening the unit to a substantial degree. 'Since the top of the unit which supports the fuel and lies close to the zone of combustion is of sheet metal and of one piece, it will be apparentthat when the unit is in service, its top may be at a fairly high temperature so that expansion stresses will be set up. If thetop of the unit were flat, as is common practise in cast metal grate bars, the expansion would tend to cause the top to be distorted and buckled and the distortion would be substantial throughout the unit because the top is continuous and the lower portion of the unit nearest the ash pan is likely to be at a much lower temperature than the top. In order to overcome this difficulty, the metal in the top of the unit is formed with projections so that expansion is prevented from becoming cumulative; These projections may be-arranged in any'desired way so as to insure that the top of the unit does not lie in a plane and therefore does not expand cumulatively with the expansion of one portion adding to the expansion of another.

I prefer to provide the top with small spaced projections of such formthat the other groups by generally horizontal air channels 23 and 24. There is a main horizontal air channel 25 extending along the top of the unit from'end to end and with this arrangement, the top of the unit has practically no portions in a plane. As a consequence, the expansion throughout the top is in a number of different directions so that there is no cumulative effect which would tend to bulge the top upwardly, fracture the welding along the seams, or produce other similar harmful results. i

Since the upper part of the unit of the side is likely to be at a somewhat higher temperature than its lower end, the heating of the side-walls17of the unit might result in an expansion of those walls which would distort the unit, unless provision were'made to prevent. The sidewalls might also buckle or bent under load, since these walls are of thin metal. In the construstion illustrated, I have overcome such difiiculties by forming each side wall during the stamping operations with stifieni ng members preferably in the form of a plurality of lugs 26 spaced apart to provide vertical air passages 27. These passages lead 'up to the top of the unit and airflowing up through them may enter the channels 24 and 25 for distribution to the fuel. I further stiffen the sides by inclined ribs 26 below the ends of lugs 26. It will be understood .that the lugs, projections, and

ribsare hollow, and by the use of these or similar expedients, both the top and side walls of the unit are preserved from distortion and strengthened. t

The units are mounted on the carrier and each unit has a recess generally designated 28, the shape of which recess is generally similar to the cross-sectional shape of the carrier. The recess is shaped so that each unit rests on the sloping top surfaces '29 of the carrier and lies freeof the flange 11. The recess in the unit is considerably larger in dimensions than the carrier so that when the carrier is rocked, each unit may move relatively to the carirer about the longitudinal axis of the latter. Atthe opening into the recess 28, each unit is provided with a pair of locking lugs 80 which "may be spaced apart a distance slightly less than the greatest overall width of the carrier or may be spaced slightly less than the width, In the first case, eachunit may be lifted free of the carrier, while in the second casesome other provision must be I made for removingthe units. In either con structioh, the lugs lie below the under surface of the web of the carrier and when the units move relatively to the carrier during rocking of the latter, the relative movement is limited in part by the engagement of a lug with the under surface of the carrier, the lugs thus serving as locking means operating alternately in accordance with the direction in which the carrier is rocked.

Since the units are made of light gauge sheet metal, provision must be made for strengthening the units at their mid-point where they have the least overall depth due to the formation of the recess to receive the flange 11. Accordingly at that point, I may omit one air passage 27, combining a pair of lugs into a double lug 31 as shown in Fig. 1. As a further means for stiffening the side walls of each unit, I provide ribs or beads 32 which extend between lugs 26 to cross the air passages 27. If desiredthere may be two lines of such strengthening means, the lower line including beads 33 which'may be bent inward while beads 32 are bent outward.

In the modified construction illustrated in Fig. 6, four of the lugs 26 are combined at the middle of the unit and this provides a flat surface 34 which I strengthen by means of ribs 35, 36, 37. The ribs 35 .and 37 are inclined to the vertical and lie at either side of the median line of the unit and along the median line is a vertical rib 36. The inclination of the ribs 35, 37, and the vertical disposition of rib 36 have been found to be most suitable in withstanding stresses to which the unit is subjected in service. It will be understood that vthe strengthening beads or ribs 32 to 37, inclusive, are provided on both faces of the unit, as are also the lugs 26.

In another form of the unit shown in Fig. 7, the two middle lugs are combined into a double lug 31, which terminates above the top of the recess 28, and the surface of this lug is provided with a shallow air passage 31 by suitably drawing the metal. In this type of unit, the center chamber has a sectional shape which is generally circular as shown in Fig. 8, and this has been found to provide great strength at the middle of the unit.

In the production of the units, the flat sheet metal blank formed to proper shape is subjected to a succession of stamping operations to give it the form illustrated, after which the meeting edges of the two halves of the blank are secured together by welding operations. This sequence of steps produces a sheet metal unit which is hollow and of substantially the same wall thickness throughout. The unit is of extremely light weight, considerably less than the weight of a unit of similar dimensions made of cast iron, and the costof production of the units by stamp ing is considerably lower than the cost of casting. The units, by reason of having portions bent or distorted out of the plane of their top and side surfaces do not become warped or buckled under heat and are strengthened by the means indicated so as to prevent warping or bending under load. While I have described the top ofthe-unit as provided with a plurality of small fuelsupporting projections and the sides with hollow lugs for the purpose of overcoming expansion diflicult'ies. which would arise: if the topand sides were flat, it will be understood that other irregular surfaces may be used for the top and sides to accomplish a similar result. The use of the lugs on the sides and the projections at'the t0p, as in the Buckley bar, aliord the advantages of the Buckley. construction and are, therefore, preferable. a

In use, the carriers are mounted in the grate frame and the units'slipped thereon by the workmen. The units'lie loosely on top of the carrier, adjacent units being keptat the desired spacing by spacing lugs 38 projecting outwardly from" certain of the lugs 26. When the bar is used in a locomotive,

the units have a self-cleaning action due to the freedom of movement which is afforded them, this movement being occasioned by the shocks and-jarsto which'the structure is subjected in service. The units reduce the total weight of the. grate structure to a very marked degree and in the form illustrated, afford the'advantages' of the Buckley bar but with a reduction in weightfar beyond that which is demanded by railroadvoflicials.

- What I claim: a

1. A-grate bar which comprises a carrier and a plurality of removable fuel-supporting units thereon, each unit being hollow, made of a single piece of sheet metal, and having portions spaced inward from its edges bent out of the plane of the sheet and serving to prevent cumulative expansion eifects. 2. A grate bar which comprises a carrier and apluralityof removable fuel-supporting units thereon, each unit'having a general plate-like shape and being'hollow and formed of a single piece of sheet metal, said unit having portions of its sides bent'out of the plane of the side and serving to prevent cumulative expansion effects. I

3. A grate bar'which comprises acarrier' and a plurality of removable fuel-support ing units thereon, each unit being hollow and made of a single piece of'sheet metal and having a fuel-supporting top having portions extending in different directions to prevent cumulative expansionin a direction lengthwise of the't'op.

4. A grate-bar which comprises a-carrier and a plurality of removable fuel-support ing units thereon, eachunit being hollow and made of a single piece of sheet metal and having irregular 'top and sidesurfaces to prevent cumulative expansion.

5. .A grate barwhich comprises-a carrier and a plurality of fuehsupporting units thereon, each unit being hollow and made of a .single piece of sheet metal and having an irregular top surface to prevent cumulative expansion in a direction lengthwise of the top,.certain of said irregularities forming fuel supports. I

6. A grate bar which comprises a carrier and aplurality of fuel-supporting units thereon, each unit being hollow and made of a single piece of sheet metal, and having side surfaces formed with irregularities to prevent cumulative expansion. 7

7. A grate bar which comprises a carrier and a plurality of fuel-supporting units thereon, each unit being hollow and made of a single piece of sheet metal and having side surfaces formed with portions extendingin different directions to prevent cumulative expansion, certain of said portions partly defining vertical passages for the flow of air to the fuel supported on said unit.

8. A gratebar which comprises a carrier and a plurality of fuel-supporting. units thereon, each unit being hollow and made of a single piece of sheet metal, said unit having a continuous one-piece top and a pair of side portions integral with the top along the side edges of the latter, the edges of said side portions contacting and :being secured together.

9. A grate bar which comprises a carrier and a plurality of fuel-supporting units thereon, each unit being hollow and made of a single piece of sheet metal, said unit having a continuous one-piece top and side portions extending from the side edges of the top and lying substantially parallel and spaced apart, said side portions having parts contacting to maintain said portionsspaced throughout the major portion of their extent. 10. A grate bar which comprises a carrier and a plurality of fuel-supporting units thereon, each unit being hollow and made of a single pieceeof sheet metal, said unit having a continuous one-piece top and side portions extending'from the side edges of the top and lying substantially parallel and spaced apart, said side portions having edge flanges extending toward each other and contacting to form a seam extending from one end of the top along the outlines of said side portions to the other end of the top, said flanges being connected by welding.

11. A grate bar which comprises a carrier and a plurality of fuel-supporting units thereon, each unit resting on the carrier and having a limited freedom of angular movement relative to the carrier about the longitudinal axis of the latter and'also having means normally free of the carrier but alternately engageable with. said carrier upon occurrence of said movement in opposite directions to limit said movement, said unit being hollow and made of a single sheet of metal, and saidsheet having spaced portions-bent out of the plane thereof to prevent cumulative expansion eflects in a direction lengthwise of the unit. 1

'12. In a grate bar, a fuel-supporting unit which is hollow and made of a single piece of sheet metal, said unit having portions of its sides bent out of the plane of the sheet to prevent cumulative expansion effects in a'direction lengthwise of the unit.

4 13. In a grate bar, a fuel-supporting unit which is made of a single piece of sheet metal having a hollow interior, said unit having portions of its sides bent outof the plane of the sheet to prevent cumulative expansion effects in a direction lengthwise of the unit.

14. In a grate bar, a fuel-supporting unit having means to permit it to be mounted on a carrier, said unit. being made of a single piece of sheet metal and having a fuel-supporting top formed with irregularities preventing cumulative expansion in a direction lengthwise of said top.

15. In a grate bar, a fuel-supporting unit having means to permit it to be mounted on a carrier, said unit being made of a single piece ofsheet metal and having side walls formed withimeans for. preventing cumulative expansion in a direction lengthwise of the unit.

16. In a grate bar, a fuel-supporting unit having means to permit it to be mounted on a carrier, said unit being made of a single piece of sheet metal and having side walls provided with means for stiflening the unit against stressesv tending to distort it, said means comprising portions of the sheet spaced inwardly from the edges thereof bent out of the plane of the sheet.

17. In a grate bar, a fuel-supporting unit having means to permit it to be mounted on a carrier, said unit being made of a single piece of sheet metal and having side walls provided with beads for stiffening the unit against stresses tending to distort it.

18. In a grate bar, a fuel-supporting unit having means to permit it to be mounted on a carrier, said unit being made of a single piece of sheet metal and having side walls provided with ribs near its mid-point disposed in the direction in which bending stresses are applied to the unit in service;

19. In a grate bar, a fuel-supporting unit having means to permit it to be mounted on a carrier, said unit being made of a single piece of sheet metal and having side walls provided with a pair of ribs one on each side ofits median line, said ribs being divergent upwardly.

20. In a grate bar, a fuel-supporting uni-t having means to permit it to be mounted on a carrier, said unit being made ofa single piece of sheet metal and having side walls provided with a plurality of vertical lugs spaced to provide air passages.

21. In a grate bar, a fuel-supporting unit having means to permit it to be mounted on a carrier, said unit being made of a single piece of sheet metal and having side walls provided with a plurality of vertical lugs spaced to provide air passages and beads extending across the space between said lugs.

22. In a grate bar, a fuel-supporting unit mountable on a carrier and made of a single sheet of metal, said unit having side Walls With meeting flanges forming the edges of the unit except at the top, said top being onepiece and continuous and the interior of the unit being an empty chamber.

23. In a grate bar, a fuel-supporting unit mountable on a'carrier and made of a single sheet of metal, a substantial part of the edges of said unit, except the top, bulging out- Wardly.

24. In a grate bar, a fuel-supporting unit mountable on a carrier and made of a single sheet of metal, the top of said unit being continuous and the side portions of said unit having angularflanges meeting each other and the end edges of said top to form seams closable by Welding.

' In testimony whereof I aflix my signature. 2

JAMES S. THOMPSON.

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