US2337100A - Grate bar lock - Google Patents

Description

Dec. 21, 1943. J; KW2 HALL s 2,337,1Q0

' GRATE BAR LOCK 'Fi1ed`sep`t- 27, 1941 2 sheets-sheet 1 INVENTOR Dec. 21, 1943. J. w. HALL 2,337,100

GRATE BAR LOCK Filed Sept.^27, 1941 2 Sheets-Sheet 2,

Patented Dec. 21, 1943 GRATE BAR LOCK John W. Hall, Conemaugh Township, Somerset County, Pa., assigner to The National Radiator Company, Johnstown, Pa., a corporation of Maryland Application September 27, 1941, Serial No. 412,629

4 Claims.

This invention relates to a grate b-ar lock, i. e., a device for preventing displacement of the grate bars of a boiler, warm-air furnace, oven, or other heating apparatus utilizing rocking or tilting grate bars.

In the use of such apparatus, it frequently happens, on tilting of the bars for shaking or dumping the fuel bed, that clinkers wedging between adjacent bars tend to throw some of the bars 01T their bearings. The replacement of the bars is a tedious and diiicult task and numerous proposals have been made hertofore for preventing grate bars from jumping oil their bearings. So far as I am aware, none of the previous proposals has entirely solved the problem and it is, therefore, an object of this invention to improve generally upon grate bar locks as known heretofore.

In a preferred embodiment of the invention, I provide a grate bar with an cverhanging end forming a concave pocket having a bearing surface adapted to engage one of a pair of trunnions extending inwardly from the wall of the combustion chamber. I also form a locking lug spaced vertically below the bearing surface adapted to engage the trunnion in the event the grate bar tends to rise as in the case of the wedging of clinkers between adjacent bars as above mentioned. The bearing surface has downward extensions which, with the locking lug, define throats adapted to receive the trunnion in certain positions only of the bar. The trunnion is so shaped that it will not pass through the throat in any normal position of the grate bar.

. I also provide grate operating means for tilting a plurality of the grate bars of a boiler furnace, such that the movement thereof is arrested before the grate bars are tilted to positions in which the throats will pass the trunnions therethrough.

In modified embodiment, the concave pocket yproviding the trunnion bearing surface, and the locking lug are formed in the wall of the combustion chamber and the trunnion integral With the grate bar.-

- The invention may be more fully comprehended by consideration of the following detailed description and explanation with reference to the accompanying drawings illustrating the preferred embodiment and modification above mentioned. In the drawings,

,Figure 1 is a view showing a portion of the grate of a boiler furnace in plan with the wall ofthe combustion chamber in section on a horizontalplane adjacent that of the grate;

Figure 2 is a transverse sectional view of a furnace showing a grate bar in elevation;

Figures 3 and 4 are elevations showing the ends of the grate bar;

Figure 5 is a diagrammatic, partial, sectional View taken transversely through the grate bars, substantially along the plane of line V-V of Figure 2;

Figure 6 is a similar View showing. the grate bars in alternate positions and illustrating the manner in which the invention serves to prevent the grate bars from jumping oli;

Figure 'l is a similar view showing one grate bar tilted to abnormal position for installation in or removal from the furnace;

Figure 8 is a view similar to Figure 5 showing a modification;

Figure 9 is a partial side elevation of the wall of a combustion chamber illustrating a further modification and showing the grate bar trunnion in section; and

Figure l0 is a partial sectional view taken along the plane of line X-X of Figure 9.

Referring now in detail to the drawings and for the present, to Figures 1 through 4, the combustion chamber of a boiler furnace is defined by the lower limbs of arched, hollow, water sections l through which water circulates to be heated. The sections are disposed side by side in the known manner and alined holes therethrough connected by bushings II. The boiler sections are supported on any convenient form of base panels (not shown).

Trunnions I2 extend inwardly from lower ends of the limbs of the boiler sections and may be conveniently cast integrally therewith. The

trunnions I2 have convex upper bearing surfaces I3 and flat sides I4. The convex bearing surfaces I3 are adapted to be engaged by cooperating concave bearing surfaces formed on the ends of grate bars I5. As shown in Figure l, each boiler section is provided with trunnions supporting one grate bar whereby the number of sections and grate bars may be chosen to obtain the desired capacity. In some cases, however, a plurality of grate bars may be carried on a single boiler section. The grate bars I5 are elongated castings having an upper, fuel-supporting surface with perforations I5' distributed thereover. In one end of the grate bar, a recess or socket I is formed to receive one of the trunnions I2. A crank arm I'I descends from the end of the grate bar in which the socket I6 is formed and terminates inla hook I8. A grate connecting bar I9 has holes spaced therealong whereby it may be disposed over the hook ends of the crank arms I1 of the several grate bars and supported thereby. Various means other than the hooks I8 may be used to hold the connecting bar in operative relation to the grate bars. One end of the bar is accessible from the front of the furnace and may be actuated by a manually operable lever to tilt the grate bars for shaking or dumping the fuel bed.

The end of each grate bar opposite that in which the socket IE is formed, is under-cut to form a pocket 2li having a concave bearing surface 2l, It will be understood that the term under-cut is used to define merely the contour of the end of the bar and not the method of shaping it. The bearing surface 2l rests on the convex upper surface of one of the trunnions I2, thereby permitting tilting movement of the grate bar as described above. The wall of the pocket 2i) has downward extensions 22 for a purpose which will appear shortly.

A locking lug 23 extends outwardly from the under-cut end of thegrate bar and` is disposed centrally below the bearing surface 2l by a distance slightly greater than the vertical dimension of the trunnion I2. The lower surfaces of the trunnions are rounded convexly as at 24 and lug 23 has its upper end shaped to conform therewith as indicated at The extensions 22 of the walls of pocket 2t form, with the lug 23, slots or throats 26 leading from both sides of the grate bar toward the bearing surface 2l. The sides of the lug 2S are generally parallel to the `extensions 22. The throats 2t are dimensioned by suitably shaping 'and spacing the extensions 22 and the lug 23, to pass the trunnions I2 only when the grate bar is tilted to a position making a greater angle with the horizontal than is made by the bar in any normal operating position thereof.

The operation of the grate bar lock will now be explained by reference to Figures 5 through 7. Figure 5 illustrates the normal position of the grate bars. In such position, the lugs 23 would engage the trunnions I2 should the grate bars tend to be lifted up. When the bars are tilted to the positions shown in Figure 6 in shaking the fuel bed, the cooperative relation of the locking lug and the trunnions is maintained so that shoulda piece of fuel or clinker such as indicated at 27, become wedged between the adjacent bars, it would be impossible for one bar to be thrown olf its bearing at the end opposite that from which the crank il depends.

As shown in Figure 6, any tendency to lift the grate bar at the left when returning the bars to horizontal position, would be resisted by engagement of the lug 23 with the adjacent trunnicn. It is further to be noted that Figure 6 illustrates the extreme position to which the grate bar may be shifted by actuating the connecting bar I5. This results from engagement of the bar i8 with the under-surface of the grate bars, thereby arresting the connecting bar before the grate bars reach such position that they can be lifted off the trunnions I2 as will now be explained,

Figure 7 illustrates the position to which the grate bars must be shifted for installation or removal. To insert a grate bar, the socket i6 thereof is rst disposed on one of the trunnions I2. Before placing the connecting bar t9' in position, the grate bar is tilted to the position indicated in Figure 7 in which the throat 26- will admit the trunnions between the extension 22 and the lug 23. Such arcuate movement of the bar may be necessary to cause proper entry of the trunnions into the slot or throat, but this is a matter presenting no difficulty. When all the bars have been positioned 'as indicated, the connecting bar may be disposed over the hook ends I8 of the cranks II of al1 grate bars.

As explained above, after the grate bars have been installed and the connecting bar placed in position, the grate bars are prevented from jumping off the trunnions at the ends opposite those in which the sockets I6 are formed. It is a simple matter, however, to remove any one grate bar should that be necessary, for repair or replacement. The connecting bar I9 is first removed and the grate bar to be replaced is tilted to an angular position such as illustrated in Figure 7. In that position, the end of the grate bar opposite that in which the socket I6 is formed, may be raised with slight angular movement so that. the throat 26 clears the trunnion I2. When the grate bar has cleared the trunnion, it may be moved axially off of the other trunnion. As previously explained, the locking lugs 23 prevent lifting of the grate bars at one end. The socket I6, obviously, prevents lifting of the bars at their other end.

The grate bar lock. described above is such as to permit end-to-end reversal of the grate bar. By the provision of the tapered throat 26 leading downwardly of the lug 23, the grate barl may be, installed or removed by tiltin-g it in the same direction regardless of whether the crank is at one end or the other. This is quite adl vantageous, particularly in large boilers where;

it is customary to provide two shaking levers at the front of the furnace, each lever operating a connecting bar cooperating with the cranks of half the grate bars. Where the possibility of positioning the grate bars in either direction is not important, I may employ the construction shown in Figure 8, which is similar to that described above in allv respects except that only one extension 22 and one throat 26 are provided, the locking lug 23' being continuous with the over-hanging wall of the pocket 2li.

A further modification of the invention which is the result of a mere reversal of the trunnions, is illustrated in Figures 9 and 10. As there shown, the wall of the combustion chamber 3l which may be the inner wall of a hollow boiler section such as that shown. in Figure 1i), is provided with a rib 32 integral therewith and providing a concave bearing surface 33 adapted. to. receive a trunnion 34 formed at one end of a grate bar 35. The other` end of 'the bar is supported in the same manner as in the case of the bars I5. The rib 32 has extensions 3S. It will be apparent that the rib 32 provides a pocket similar to that shown at 20 in the end of the` grate bar I except that itis inverted. A locking lug 3l is4 also formed integral with the wall: 3l and is located centrally of the rib 32 and spaced thereabove. The trunnion 36 has flatv sides like the trunnions l2 and the extensions 3bA cooperate with the lug 37 to define slots or throats 38 through which the trunnion Sil may be passed when the grate bar is tilted to an angl@ beyond that to which it is actuated in the normal tilting movement incident to shaking or dumping. The grate bai 35 is installed and removed in the same manner as already described for the bars I5.

It. will be apparent that the invention is characterized by numerous advantages. The structure providing a lock for preventing the grate bar from jumping 01T its bearing, is simple and inexpensive. The lock is equally effective whether the4 bar is in its normal or horizontal position, or is tilted for shaking or dumping. Any bar may easily be removed, nevertheless, without disturbing the others. The accidental movement of the grate bar past the locking position is prevented since movement of the grate connecting bar is arrested before the grate bars have been tilted too far. The reversibility of grate bars provided with my lock has already been mentioned. This is a further advantage in that it is not necessary to stock different bars having cranks at the left hand and right hand ends. A further advantage is that the grate bar lock does not reduce the area of the rounded upper bearing surface of the trunnions supporting the grate bar. rI'his bearing surface conforms to the contour of-concave pocket at the end of the grate bar and has an extensive area of contact therewith. As previously stated, furthermore, the locking lugs may be integral with the grate bar, thus avoiding the necessity for any additional manufacturing operations.

While I have shown the grate bar lock of my invention at only one end of the bar, it may also be formed at both ends if desired, or on the end opposite that on which it is illustrated. Similarly, as shown in the drawings, trunnions may be formed on the grate bar and cooperate with a bearing surface in a concave pocket formed on the wall of the boiler section.

Since the grate bar lock is eiective when the bars are in their normal position, it is impossible to dislodge a grate bar while working the fuel bed with a poker or splice bar.

While I have illustrated and described but a preferred embodiment of the invention with slight modifications, it will be recognized that changes in the construction and arrangement disclosed may be made without departing from the spirit of the invention or the scope of the appended claims.

I claim:

l. In a grate, pairs of spaced supports, a grate bar tiltable on cach pair of supports, and locking means comprising a portion of the bar overhanging one end thereof and forming a concave pocket having a bearing surface engaging one of said supports, a locking lug on the bar spaced below said surface and normally adapted to engage said last-mentioned support should the bar tend to rise, said one of said supports having flat sides and a convex top engaging said surface, said surface and lug being spaced sufficiently to clear said one of said supports only when the bar is tilted through an angle greater than that through which it is turned for normal shaking and dumping, and moved generally parallel to said sides.

2. In a grate, a plurality of bars, trunnions tiltably supporting the bars, each bar having a portion overhanging at one end to provide a pocket with a concave bearing surface adapted to engage a supporting trunnion, said surface having a downwardly inclined extension, and a locking lug on said bar spaced below said surface, the side of the lug adjacent the extension being generally parallel thereto, said lug and said extension dening a slot adapted to admit said trunnion, said trunnion being shaped oblong in cross-section to clear said slot only when the bar is tilted to a position beyond its extreme normal operating positions.

3. In a grate, pairs of spaced trunnions, a grate bar tiltable on each pair of trunnions, one end of said grate bar having an overhanging portion providing a pocket on which a trunnion-engaging surface is formed, the trunnion engaged by the surface of said pocket having a greater dimension vertically than horizontally, and a throat extending at an angle from said pocket dimensioned to clear said last-mentioned trunnion only when the grate bar is tilted to a position beyond the limits of its normal tilting movement.

4. In a tilting grate bar, locking means for preventing jumping of the bar from its normal position relative to a furnace wall comprising an overhanging shoulder at one end of the bar providing a bearing surface concave downwardly, said surface being adapted to engage a pivotal support rounded on top but having a greater dimension vertically than horizontally, and a locking lug on said end of the bar spaced below said surface, having generally flat sides and projecting beneath said support, said surface having a downwardly inclined extension defining with the adjacent side of the lug a throat adapted to clear the width of the support when said end of the bar is raised relative thereto, only after the bar has been tilted through an angle greater than that through which it is tilted for normal shaking and dumping.

JOHN W. HALL.

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