US2845057A - Furnace-installed humidifier - Google Patents

Description

July 29, 1958 R. P. sKERRl-r'r FuRNAcE-INSTALLED HUMIDIFIER 5 Sheets-Sheet 1 Filed Jan. 4. 1954 www.

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@y lp. oS'eTP/y/ BY illnu United States Patent O FURNAcE-rssrALLED lHUMIDIFIER Roy P. 'Skerrit Detroit, Mich., assigner to conomatic Products Company, Detroit, Mich., a corporation of Michigan Application January 4, 19'54, Serial No. 402,075

3 Claims. (Cl. 126-113) This invention relates to humidifiers and, in particular, to furnace-installed humidiiiers.

One object of this invention is 'to provide a furnaceinstalled lhumidifier wherein a mounting bracket is adapted to be secured adjacent an opening in the furnace wall, the bracket having outwardly-projecting spaced `parallel wings and a humidiner pan fulcrum on which a humidifier pan is tiltably mounted and, `by reasons of its tilting in response to variations in the water level due to evaporation, actuates a lever mounted on one wing of the bracket which in turn opens or closes the water supply valve mounted on the other wing of the bracket to start and stop the ow of the water for refilling the pan.

Another object is to provide a furnace-installed humidifler of the foregoing character wherein the speed of evaporation of the water is enhanced by the use of evaporator plates of porous material such as molded glass `fiber, or ceramic material, mounted in an evaporator plate rack which is placed in and slidably movable along the tilting pan relatively to its fulcrum, and the balanced condition of the pan is restored by the use of this adjustably slidable plate rack as a Acounterbalancing weight applied to the pan in order to counteract the unbalancing effect of the weight of the evaporator plates, means beingprovided for locking the plate rack in its adjusted position. 'l

Other objects and advantages of the invention will become apparent during the course of the following description of the accompanying drawings, wherein:

Figure l is a central vertical section through a furnaceinstalled humidifier according to one form of the invention, taken along the line 1 1 in Figure 2;.

l Figure 2 is a top plan View partly in horizontal section, along the line 2 2 in Figure 1;

Figure 3 is a vertical cross-section taken along the line 3-3 in Figure 2, using a wide humidifier pan;

Figure 4 is a Vertical cross-section t'a'ke'n along the line 4-4 in Figure l; y A i Figure y5 is an enlarged fragmentary vertical section through the nozzle and seat 'of the water 'supply valv'e taken along the line 5-5 in Fig'ure 2;

. Figure 6 is a front perspective view of the mounting bracket of the humidifier shown 'in Figuresl yto inclusive, wi'th the cover plate omitted; p i

Figure 7 is afront perspective view ofthe 'cover plate us'ed with Athe mounting bracket of Figure '6; I

Figure-8 is a perspectivel view of a partition'plate used with the mounting braket showni'n Figure 6;`

yFigure 9 is across-section similar to `Figure 3, but "showing Ithe use of a narrow humidifier pan Ywith 'a modified bafiie' plate; i

Figure 10 is a fragmentary vertical section taken along thel line 10-10 in Figure 9; i' y y Figure 11 is a perspective Yview yof the modified balile plate used with the narrow humidifier pan of Figures 9 and 10; y

Figure l2 is a side elevation of 'a modified humidifier pan adapted -to preventtloodirig of th'efurnace when used i'high water pressure areas,

ice

2 Figure 13 is a fragmentary vertical 'section 'similarto Figure 3, showing a modification of the water control valve and its operating mechanism; and

Figure 14 is a top plan View, partly in horizontal section, of the modified humidifier shown in Figure 13, taken along the line 14'-14 therein.

Referring to the drawings in detail, Figures 1 to 4 inclusive show a furnace-installed humidifier, generally designated 20, according to one form of the invention as consisting generally of a mounting structure 22 applied to a furnace 24, such as to the dome of a conventional hot air furnace, a humidifier pan 26 tiltably mounted upon the mounting structure 22, and a water-level-responsive water supply valve unit 28 mounted inthe mounting structure 22 adjacent the outer end vof the humidifier .pan 26.

The mounting structure 22 is turn consists of a mounting bracket, generally designated 30 (Figure 6), stamped froinsheet metal and having an attachment plate 32 with an approximately rectangular aperture 34 therein and forwardly-projecting parallel plate wings 36 projecting forwardly from the vertical edges 38 of the `aperture 34 a's yfold lines, the aperture 34 having horizontal edges 40. The lower edge portion 42 of the mounting bracket 30 is oifset'sligh'tly relatively to the remainder thereof in order to accommodate a partition plate, generally designated 44 (Figure 8). The wings 36 have aligned approximately V-shaped slots 46 in their lower portions to receive fasteners 47 (Figure 1) rfor 4'the mounting of a humidifier pah fr manual rather than automatierefilling, as described more specifically below. -Above the V-s'haped slots 46, th'ewindings 36 are 'further provided with aligned r'ect'angular holes 48 for the mounting of the water supply unit 28. The outer edges S0 of the wings 36 are preferably rounded and the/wings 36 at their upper ends terminate in notches 52, both being provided for receiving and holding a cover, generally designated 54 (Figure 7).

The cover 54 is formed of sheet material or other 'suit'- able material and has a front face 56 with an upper curved portion 58 fitting the curved edges V50 of the wings 36, and a downwardly-projecting ange `60, the ends of which'en'ter the notches 52 when the cover 54 is installed on the wings 36. Edge anges 62 follow the contours `of thev lateral edges 64 of the cover 54 and overhang the edges 50 of the wings 36. The attachment plate 32 is suitably drilled Vas at 66 to receive fasteners 68 (Figure l) by which it is secured to the wal170 of the furnace 24.

The partition plate 44 is of generally rectangular outline'with afhole 72 by whichI it is secured by one of the fasteners 68 between they mounting portion 32 o'f the bracket-30 and the yfurnace'wall 70 (Figures '1 and 8). Right-angled 'notches 74 are cut inthe lower opposite icornersoff the vpartition plate 44 in order that the lower portion 76 thereof will enter the' interior of the humidifier P21926 (Figurey j Near its .lower edge 78, each of ythe wings 36 of the mounting bracket 30 is provided with a pair of holes S0 and 82 respectively. These holes are provided for thev purpose of attaching a fulcrum plate,generallyY designated 84 (Figures 1 and 4), upon which the pan 26 is tiltably supported. The fulcrum plate S41 has a fiat bottom v86 with side and rear flanges 88 and 90-rising from the side and rear edge thereof respectively. The front or forward portion of the fulcrum plate 86 is cutl away as at 92 (Figures l and 2) lso that the `forward edge 94 thereof isset back 'from the forward ends of the side flanges 88. T hisy cutaway-.portion 92 provides freedom of action for the forward endof the humidifier .pan 2'6when it tilts downward. The rearward edge flange serves as a fulcrum for ythe humidifier pan 2'6, which is prevented from lateral displacement by vari pstanding, locating lg or tab 96 strek'upeui erweitertem-'persen s6 (Figures 1 am 4).

The fulcrum plate 84 is secured to the side Wings 36 of the mounting bracket by fasteners 98 passing through the holes 80 or 82 therein and likewise passing through the side anges 88 of the fulcrum plate 84. The fulcrum plate 84 projects through an opening 100 of rectangular outline formed in the furnace wall 70, and rests upon the lower edge 102 thereof (Figure 1).

The humidifier pan 26 is of elongated shape having side walls 104, front and rear walls 106 and 108, and a bottom wall 110 (Figure 1). The bottom wall 110 is provided with parallel laterally-extending grooves 112 and 114 respectively for receiving the upper edge 116 of the fulcrum plate ange 90. Two grooves 112, 114 are shown, but more or less may be provided to facilitate the proper balancing of the humidifier pan 26. In its mid-portion, the humidifier pan 26 is provided with an elongated longitudinal groove or recess 118 for receiving the locating lug 96 (Figures 1 and 4).

The humidifier pan 26 is optionally provided with an evaporator plate support, generally designated 120 (Figures l, 2 and 4) also made from sheet metal in troughshaped form and having a fiat bottom wall 122, inclined side walls 124, narrow top walls 126, adapted to engage the upper edges of the humidifier pan side walls 104, and vertical edge lianges 128 adapted to overhang the side walls 104. At its forward end the evaporator plate support 120 is cut back as at 130 (Figure 2) so that the top wall 126 projects slightly forward of the bottom and side walls 122 and front 124, terminating in downwardly-bent hook portions 132 engaging suitably located laterally-aligned notches 134 in the upper edges of the side walls 104 (Figure 1). This construction prevents accidental displacement of the evaporator plate support 120 lengthwise of the humidifier pan 26.

The bottom and side walls 122 Iand 124 of the evaporator plate support 120 are provided with multiple lateral slots 136 arranged in spaced parallel relationship. Mounted in the slots 136 and projecting downwardly through them are evaporator plates, generally designated 138, of any suitable porous material, such as molded glass fiber, rock Wool, ceramic material, or the like. These evaporator plates 138 have truncated triangular lower end portions 140 formed by converging lower side edges 142 for the purpose of passing through the slots 136 and entering the water W in the pan 26 (Figure 4). The spacing of the slots 136 correspondingly spaces the evaporator plates 138 apart from one another. The side edges 142 of the evaporator plates 138 engage the evaporator plate support 120 at the ends 144 of the slots 136.

The front wall 106 of the humidifier pan 26 is provided with an elongated horizontal slot 146 (Figure 3) in which a valve-operating pin or rod 148 is adjustably mounted, the pin or rod 148 having a reduced diameter threaded outer portion 150 for receiving a nut 152 with washers 154. Mounted in the rectangular hole 48 in one of the side wings 36 of the mounting bracket 30 is the threaded attachment portion 156 of the fulcrum bracket 158 of the water supply valve unit 28. The bracket 158 is L-shaped and is held in place by a nut 160 threaded on the portion 156 aided by washers 162 (Figure 3). The lower end of the bracket 158 is drilled to receive a pivot pin 164 upon which one end of a correspondingly-drilled lever arm 166 is pivotally mounted. The arm 166 rests upon the operating pin or rod 148 and carries a counterweight 168 which is bored as at 170 to receive the rod 166 and secure it in its adjusted position by a set screw 172. The free end of the arm 166 carries a cup-shaped or recessed valve seat support 174 (Figure 5) in the recess 176 of which a cupped valve seat 178 is secured, as by cementing or vulcanizing.

The cup-shaped valve seat 178 is of so-called elastic deformable material, such as natural or synthetic rubber or synthetic plastic and has an upstanding rim fiange 180 providing a cup 182 into which the end portion 184 of a water nozzle 186 extends downward into engagement with the upper surface 188 of the valve seat 180. The cup or recess 182 provides for immersion of the end portion 184 of the water nozzle 186 so as to protect it from erosion resulting from the heat in the furnace reacting with and oxidizing the metal at the end of the nozzle. The nozzle 186 is surrounded by a radially-spaced skirt or rim flange 190 which extends downwardly into overlapping relationship with the upstanding flange 180 on the valve seat 178, so as to provide further protection for the nozzle end portion 184.

Water reaches the nozzle 186 through a passageway 192 in a fixture 194 integral with the nozzle 186 (Figure 5) and having a reduced diameter tubular threaded portion 196 which passes through the other ofthe rectangular holes 48 in the other wing 36 and is held in position by a nut 198 threaded thereon, aided by washers 199. Because of the vertically-elongated shape of the rectangular holes 48, the fulcrum bracket 158 and the nozzle fixture 194 may be adjusted upward or downward, as desired.

The modified humidifier construction, generally designated 200, shown in Figures 9, 10 and 11, is generally similar to the humidifier 20 shown in Figures 1 to 8 inclusive, and corresponding parts accordingly bear similar reference numerals. The modified humidifier 200 differs from the humidifier 20 in that it permits the use of a humidifier pan 202 which is narrower than the humidifier pan 26 in Figures 1 to 8 inclusive. Accordingly, a slightly different partition plate 204 is provided (Figure l1) substantially similar in all respects to the partition plate 44, except that its lower portion 76 is provided with a pair of upwardly-extending elongated parallel notches 206. These notches receive the side walls 104 of the humidifier pan 202 which is likewise of similar shape to the humidifier pan 26. The side walls 104 of the humidifier pan 202 are optionally extended upward a sufiicient distance to require notches 208 in their upper edges for the passage of the lever arm 166. The notches 206 provide downwardly-extending side wings 209 on opposite sides of the narrow pan 202 for further protecting and shielding the apparatus from direct heat.

The modified humidifier pan, generally designated 210, shown in Figure 12 is similar in general construction to the humidifier pans 26 and 202 previously described and similar parts likewise bear similar reference numerals. The humidifier pan 210, however, is especially Well adapted for protection of the furnace against ooding, especially when installed in geographical areas, such as mountainous areas, having high local water pressures for insuring that the city Water will reach houses located on elevated ground. Prior tilting pan humidifiers have been unsuccessful in such localities for the reason that a sudden blast of water at high pressure is released when the nozzle is uncapped. Hitherto, this high pressure jet of water has tilted the forward end of the humidifier pan downward with a jolt, the delicately-balanced pan being held down by the force of the water jet for a sufficient length of time to cause the forward end of the pan to fill up and overflow, so that a sufiicient amount of water cannot flow to the rearward end of the pan to cause it to tilt on its fulcrum and close the valve. The improved humidifier pan 210 solves this diiculty by providing a two- stage rear Wall 212 and 214, with a higher level bottom wall 216 in the humidifier pan extension 217 formed thereby. Normally, the Water occupies the lower portion 218 of the pan 210 beneath the level of the upper bottom wall 216 and between the front wall 106 and lower rear wall 212. The fulcrum pan 210 is balanced in this position for rocking motion in its fulcrum grooves 114 or 116 upon the fulcrum fiange of the fulcrum plate 84 (Figure l). If, however, the pan 210 is installed in a high water pressure locality and the valve is kept open temporarily by the force of the downwardly-directed jet of water from the nozzle 186, ooding is prevented by reason of the fact that as soon as the water level rises above the level of the upper bottom wall 21'6, it moves rearwardly into the upper pan portion 217 which is considerably longer than the lower pan portion 218. The result .is that ythe weight of the water filling the upper extension pan portion 217 quickly overbalances the effect of the waterjet issuing from the nozzle 186 and closes the valve seat Iagainst the nozzle, nothwithstanding the force of the water jet issuing therefrom.

The further modified humidifier, ,generally designated 220, shown in Figures 13 and 14, is generally similar to the humidifier 20 of Figures 1 to 8 inclusive, except that a different construction of water supply valve unit, generally designated 222, is provided. The humidifier vpan 26 and mounting bracket 30 remain the same as previ ously described above, together with the -operating `rod or pin 148 in the horizontally-elongated slot 146. The valve unit 222 is provided with a combined bracket and nozzle fixture 224 having a threaded reduced diameter portion 226 adjustably mounted in one of the slots 48 of one of the wings 36 of the mounting bracket 30, and anchored in posi-tion by a nut 228 and washers 230. The member 224 is tubular, containing an L-shaped water passageway 232 terminating in an annular nozzle 234 similar to the nozzle 186 and similarly provided with a cupped valve seat 236 of elasticized deformable material.

An annular identation 238 surrounding the nozzle 234 provides a ring-shaped recess which further protectsithe nozzle 234, in a similar manner to the protection afforded by the annular skirt 190 of the nozzle 186 (Figure 5). The nozzle fixture 224 is more elongated than the `nozzle fixture 194 of Figure 5, and at a location adjacent its junction with the reduced diameter portion 226 is bored to receive a pivot pin or fulcrum pin 240 upon which an upwardly-facing lever arm 242 of channel-shaped crosssection is pivotally mounted. The valve seat 236 is mounted in a cupped valve seat support 244 secured within the channel arm 242, the latter being drilled at 246 for the passage of a stop screw 248 threaded into a threaded hole 250 in the bottom of the fixture 22,4.

Mounted in the channel of the lever `arm 242 nearer'the free end thereof than the valve seat 236 and stop screw 248 is -a counterweight 252 bored and threaded to receive a clamping screw 254. The clamping screw 254 is located at such a level that when the counterweight 252 is restingiupon the fioor or web 256 of the channel in the lever arm 242, the shank ofthe screw 254 passes over the upper of one of the fianges 258, whereas the head of the screw 254 engages the flange 258 and`clamps the counterweight 252 in its adjusted position.

Operation In the operation of the humidifier 20 shown in Figures 1 to 8 inclusive, let it first be assumed that the owner of the furnace 24 prefers to install the humidifier for manually-filled operation rather than for automatic filling. Such preference may arise, for example, for reducing the first cost of the apparatus. In this instance, the valve unit 28 and fulcrum plate 84 are omitted. The rectangular aperture 100 of suitable size is cut in the side wall or dome 70 of the furnace 24 and the mounting bracket 30 is secured to the wall 70 by means of the fasteners 68. Since the valve unit 28 is omitted, it is unnecessary to provide the partition plate 44, the principal purpose of which is to protect the water supply valve unit 28 and which is inserted in position between the attachment plate 32 and the furnace wall 70 (Figure l). The humidifier pan 26 is inserted through the furnace -opening 100 and supported on its upper edge 102, as shown in the dotted lines indicated by the dotted reference arrow 26 in the lower right-hand corner of Figure l. If desired, the evaporator plate support 120 and evaporator plate 128 may also be installed, in which case the partition plate 44 would be left off until the installation had been made, and then inserted and clamped in position by the remaining fastener 68 in the top central portion of the attachment plate 32. The fasteners 47are then inserted-through the V-shaped slots 46 -andf'tiirough suitable holes in the lhumidifier pan 26 to secure the latter firmlyrin position. With the manually-filled humidifier thus installed, `the user `insertsthe water W from the front by means of a kettle or pitcher wi`th-a spout, after which heplaces ythe cover'54v 4in kposition by dropping its forward flange 60 into the notches 52 provided (forit. The cover v54 then occupies'the position shown'in Figure '1, with the side flanges 62 thereof overlapping the side edges-50 of the wings l36. The water lW has to be replaced manually from time to 'time as it evapora-tes.

VIf, on the other hand, the owner wishes an automatically-filled humidifier 20, either at the outset or after having installed the manual installation, he purchases the fulcrum plate 84 and wa-ter supply valve unit 28 shown in Figures l 'to 5 inclusive., lInstead of installing the humidifierv ,pan '26 `rigidly in the dotted line position of Figure y1 onthe furnace-opening edge '102,-he installs the fulcrum ,plate 384 in its place, securing the plate 84 in position by the screws 98. He then installs the valveunit 28' in the aligned holesl'48, and inserts the humidifier pan 26 after equipping it with the operating rod or pin 148. The latter is adjusted lengthwise of the slot 146 until it exerts the ,proper `lifting force on the valve lever 166, in accordance with the local .water pressure, so as to urge the resilient valve seat 178 upward against .the nozzle 186 with a suitable force. The fulcrum pan 26 is balanced upon one or the other of the grooves 112-or 114 and fulcrum flange 90 (Figure l) with the locating lug 96 projecting lupwardly into therecess 118-to prevent lateral motion 'of 'the humidifier pan26. `As beforeftjhe evaporator plate support .-1.20 and evaporator plates 138 are inserted in their proper positions, with the hook portions `132-resting on one of the notches 134. The vparti.- tion vplate 44 is also inserted and clamped in position, and the humidilierpan l26 filled -t'o the proper level. From Figure .1, it will `be 'seen that the rear wall`108 of the humidifier pan 26 is located at a greater distance from either of the fulcrum grooves 114 than the forward wall 106, so that a greater amount and consequently a greater weight "of`ivvater'lies in the portion of the pan rearwardly of the fulcrum grooves l112 or 114 than forwardly thereof. This greater'weight of water causes the forward end wall 106 to' tilt upward, causing the operating rod or pin 148 t'o movethe lever arm l166 upward, pushing the valve seat 178 upward against the lower end 184 of the nozzle 1,86 (Figure 5), closingthe nozzle 186'and halting further flow of the water. 1

i When, -as a result of the operation of the furnace, hot air in 'the chamber in which the humidifier pa'n V'26 Ais located causessufiicient evaporation of the water W therein to require replenishment, the pressure of the water standing in the passageway 192 of the nozzle 186 overcomes the force exerted by the differential weight of the rearward portion of the humidifier pan 26, pushing the valve seat 178 and lever arm 166 downward so as to open the valve 194 and permit the water to flow therefrom into the humidifier pan 26. When the water level has risen to a sufficient height to voverbalance the pressure of the water in the nozzle 194, the consequent tilting of the humidifier pan 26 on the fulcrum ange 90 causes the upward motion of the operating rod 148, lever arm 166, and valve seat 178 to close the passageway 192 in the nozzle 186 and prevent further flow of water for the time being. Meanwhile, however, a small amount of water will remain in the annular recess formed by the cup-shaped depression 182 surrounding the nozzle 184 (Figure 5), protecting the lower end 184 of the nozzle 186 from oxidational erosion. The partition plate 44 further shields the valve unit 28 from the hot air of the furnace, preventing further erosion. If evaporator plates 138 have been mounted in the humidifier pan 26, the counterweight 168 is employed with the lever arm 166,

-to compensate for the added weight thereof, otherwise the counterweight 168 is omitted.

The operation of the modified humidifier 200 (Figures 9, 10 and 11) is substantially identical with that of the humidifier as described above, the sole substantial difference being the ability to use a narrow humidifier pan 202 in place of the Wide pan 26 in the same mounting bracket 30, the tabs 209 in the partition plate 204 filling in the spaces on opposite sides of the narrow pan 202.

The operation of the modified humidier pan 210 of Figure l2 has been described above in connection with its construction, hence requires no repetition. As stated above, the upper chamber 217 above the upper level bottom portion 216 provides a sudden increase of the volume and weight of water at the rearward end of the humidifier pan 210, positively closing the valve unit 28 despite the rush of water tending lto keep it open when the humidifier is installed in high water pressure localities.

The operation of the modified humidier 220 of Figures 13 and 14 is also generally similar to that of the humidifier 20, except that the lever arm 242' has the counterweight 252 located at the free end thereof rather than between the fulcrum and the valve seat 236, as in Figures 1 to 8 inclusive. The excessive downward motion of the lever arm 242 is prevented by the head of the stop screw 248, so that the valve 222 can open only to a desired extent.

What l claim is:

1. A furnace-installed humidifier comprising a mounting structure including a mounting bracket adapted to be secured adjacent an opening in the furnace wall and having a humidifier pan support including a fulcrum thereon, an elongated humidifier pan tiltably mounted upon said fulcrum at a location providing a greater volume of water in said pan rearwardly of said fulcrum than forwardly thereof and arranged to project through said opening into the interior of said furnace, a water supply valve arranged to discharge into the forward portion of said pan and including a valve seat element and a valve nozzle element, and valve-operating mechanism connected to one of said valve elements and responsive to the tliting of said pan upon said fulcrum for opening and closing said valve, said mounting bracket having side wings spaced apart from one another and projecting outwardly therefrom on opposite sides of said pan, one of said valve elements being mounted on one of said wings and said valve-operating mechanism being mounted on the other wing and operatively connected to said pan.

2. A furnace-installed humidifier comprising a mounting. structure including a mounting bracket adapted to be secured adjacent an opening in the furnace wall and having a humidifier pan support thereon including a humidierl pan fulcrum, an elongated humidifier pan tiltably mounted upon said fulcrum and arranged to project through said opening into the interior of said furnace, means for holding said pan in assembly with said mounting structure, and an evaporator plate rack disposed substantially in its entirety in the upper portion of said pan above the maximum water level therein, said rack resting upon and having opposite edge projections slidably and adjustably engaging the upper side edges of said pan and extending thereacross, said rack being adjustably movable along said pan relatively to said fulcrum, and means for holding said rack in its adjusted position.

3. A furnace-installed humidier comprising a mounting structure including a mounting bracket adapted to be secured adjacent an opening in the furnace wall and having a humidifier pan support thereon including a humidifier pan fulcrum, an elongated humidifier pan tiltably mounted upon said fulcrum and arranged to project through said opening into the interior of said furnace, means for holding said pan in assembly with said mounting structure, and an evaporator plate rack disposed substantially in its entirety in the upper portion of said pan above the maximum water level therein, said rack resting upon and having opposite edge projections slidably and adjustably engaging the upper side edges of said pan and extending thereacross, said rack being adjustably movable along said pan relatively to said fulcrum, and means for holding said rack in its adjusted position, said rack having spaced substantially parallel slots extending thereacross for receiving spaced parallel evaporator plates.

References Cited in the file of this patent UNITED STATES PATENTS 1,458,549 Sallada lune 12, 1923 1,720,241 Sallada July 9, 1929 1,817,357 Fisher Aug. 4, 1931 1,878,817 Buehrer Sept. 20, 1932 1,936,895 Anetsberger Nov. 28, 1933 2,049,731 Betts Aug. 4, 1936 2,565,210 Dovolis Aug. 21, 1951 2,573,158 Muth et al. Oct. 30, 1951 2,585,764 Getz Feb. 12, 1952 2,588,567 Perlman Mar. 11, 1952 2,678,235 Perlman May 11, 1954 2,709,427 Perlman May 31, 1955

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