US2504048A - Control device for fuel burners - Google Patents

Description

April 11, 1950 H. w. RICE 2,504,048

I CONTROL DEVICE FOR FUEL BURNERS Filed Nov. 29, 1944 2 Sheets-Sheet l 5 IN V EN TOR. H. {9 Ha -0L0 ca Plea-1 April 11, 1950 H. w. RICE CONTROL DEVICE FOR FUEL BURNERS 2 Sheets-Sheet 2 Filed Nov. 29, 1944 INVENTOR. 69.92040 W. PIC'E':

BY M

Ms HTTOANE).

Patented Apr. 11, 1950 2,504,048

UNITED STATES PATENT OFFICE CONTROL DEVICE FOR FUEL BURNERS Harold W. Rice, Lynwood, CaliL, assignor to Robertshaw-Fulton Controls Company, a corporation of Delaware Application November 29, 1944, Serial No. 565,608

Claims. (Cl. 137-139) This invention relates to control apparatus for fuel burners and, more particularly, to combined ignition and safety controls.

One object of the invention is to secure condition and safety control with a single control means.

Another object of the invention is to operate a single control means by a novel type of lever action.

Another object of the invention is to render the control means operable only when the safety apparatus permits.

Another object of the invention is to afford easy access to the operating parts of the control and particularly the parts requiring manual op eration to bring the control into operation.

Another object of the invention is to reduce the unavoidable pressure drop in a fluid fuel control system using valves to control fluid flow.

'Another object of the invention is to render the control apparatus easily installed in existing fuel burner arrangements without expensive and difilcult alterations.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawings, wherein:

Fig. l is a rear view in somewhat schematic form of the condition and safety control apparaof Fig. 1;

Fig. 4 is a side elevation similar to Fig. 2 of a modification;

Fig. 5 is a rear view similar to Fig. 1 of the modification shown in Fig. 4;

Fig. 6 is a partial section similar to Fig. 3 of the modification shown in Figs. 4 and 5;

Fig. 7 is a cross-section similar to Fig. 2 but showing a further modification; and

Fig. 8 is a rear view similar to Fig. l of the further modification shown in Fig. 7.

. Referring more particularly to the drawings, Figs. 1-3, the control apparatus is conveniently mounted on the back guard It of a domestic gas range having a front panel [2 which faces the operator. A control body I4 is mounted on the back guard l0, rearwardly of the panel l2, by means of the screws It. The control body houses a control means I8 and an electromagnetic safety means 28 spaced one from the other in substantially the same horizontal plane. An actuating means 22 is secured by any suitable device (not shown) to the back guard to surmounting the control body l4. As will be apparent hereinafter, the actuating means 22 is operable at a point spaced from the plane of the control means l8 and electromagnetic safety means 20, but intermediate thereof, so as to form a trian ular relationship therewith.

The control means i 8 of this embodiment takes the form of a valve member 24, shown in. broken lines in Fig. 3, which is adapted to cooperate with a valve seat 26 to control flow of gaseous fuel from an inlet 28 to an outlet 30 formed in the control body l4. A conventional gas burner 3| receives the fuel from the outlet 30 when the valve member 24 is open. The valve member 24 is provided with a stem 32 which projects from the control body i4 and provides means for operating the valve member 24 to open position from the exterior of the control body M. The valve member 24 is biased toward the seat 26 by a coil spring 34 which may be overcome by pressure applied to the projecting end of the valve stem 32.

The electromagnetic safety means 20 comprises, in this embodiment, a magnet housing 36 secured in the control body i4 by a cap member 31 and within which a horseshoe type magnet 38 is rigidly mounted. An armature 48 is adapted to be moved into attracted position with the pole faces of the magnet 38 by manual pressure applied through a button 42 which extends from the armature through a suitable bearing 44 in the housing 36. In order to provide for operation of the button 42, the panel i2 of the back guard 10 is suitably apertured as at 46 and the button 42 made sufllciently long to project therethrough. A reset stem 48 is carried by the armature 48 on the side opposite the button 42 and projects through the magnet 38 and cap 31 exteriorly of the control body l4.

A winding 50 for the magnet 38 is adapted to be energized by current generated by a thermocouple 52. As shown schematically in the drawing, the thermocouple 52 is electrically connected at one end with the winding 50 and has its hot junction exposed to the flame of a pilot burner 54. v v The pilot burner 54 may receive fuel by way of a conduit 56 connected to the inlet 28 and is therefore of the constant burning type. It will be apparent, however, that suitable arrangements could be made to shut off the flow of fuel to the pilot. burner-when the valve 24 controlling flow of fuel to the main burner is closed. As both constant burning pilot burners and those provided with per cent shut-off are well known to those skilled in the art, either type may be used in carrying out the principles of this invention.

The actuating means 22 of this embodiment takes the form of an electric clock having an actuating stem or plunger 58 projecting therefrom. The construction of the clock has no signiflcance in this invention and any commercially available type of timing device would serve the purpose, provided a reciprocating element such as the plunger 58 is associated therewith. It will be understood that at the start of an automatic cycle the plunger 58 initially occupies a retracted position indicated by the broken line in Fig. 2. When the timed operation is to begin the plunger 58 is adapted to be extended to the full-line position shown. This position is maintained until the occurrence of the desired condition, such as termination of the timing period when the plunger retracts to the broken line position. It will further be understood that other condition responsive means could be substituted for the electric clock and that the conditions could be pressure, temperature, humidity, among others. This invention is more particularly directed toward means for operating the valve member 24 to control flow of fuel to the main burner 3| for the period set by the clock or other condition controlling means and, at the same time, to cause this valve to close to shut off the fuel supply to the main burner 3| in the event that the pilot burner 54 becomes extinguished. To this end, a simple lever device 60 is provided for transmitting movements of the plunger 58 to the valve stem 32 and also for transmitting movements of the reset stem 48 to the valve stem 32.

In the embodiment shown in Figs. 1-3, the lever device 60 takes the form of a single triangular-shaped plate 62 adapted to engage with the valve stem 32, reset stem 48 and plunger 58 at each of its apices respectively. If desired, the engaging portions of the valve stem 32, reset stem 48 and plunger 58 may be pointed and the adjacent apices of the plate 62 may be provided with depressions to afford support therefor.

The plate 62 is adapted to be pivoted at a point intermediate the points of engagement adjacent its apices but on the opposite side thereof. The pivot may take the form of a screw 64 adjustably mounted in a channel-shaped plate 66 secured by welding or other suitable means to the underside of the back guard i0. Preferably, the pivot 64 is positioned equidistant of the apices of the plate 62 but may be located at any point within the triangle depending on the lever ratio required.

If desired, the engaging end of the screw 64 may be pointed and the adjacent portion of the plate 62 suitably depressed as described in connection with the other points of engagement of the plate 62. Moreover, it will be noted that the pivot point can be adjusted forward or backward by rotating the screw 84. As the plate 82 necessarily projects upwardly through the back guard I 0 a suitable slot 68 may be provided therein to afford clearance for free movement of the plate on the pivot 84.

A coil spring 70 extends in axial alignment with the reset stem 48 between the plate 62 and a depending portion 12 formed on the channelshaped element 86. The spring 18 forms a yieldable means for rotating the plate 82 on its pivot 64 when the armature 40 resumes a released position.

The control is shown in the normal running position in Figs. 1-3 of the drawings, wherein the valve member 24 is open, the armature 40 is engaged with the pole faces of the magnet 38 and the plunger 58 of the electric clock is in its extended position. Under such circumstances the thermocouple 52 is being heated by the pilot burner 54 and the main burner 3| is in operation.

In the starting position, the plate 62 occupies the position indicated by the broken lines in Figs. 2 and 3 of the drawing. Thus, the plunger 58 is shown in Fig. 2 as retracted and the plate 62 occupying a tilted position. In Fig. 3 of the drawing, the broken line position of the reset stem 48 causes the plate 62 to occupy substantiallythe broken line position thereof, although the actual position would be somewhat different due to the valve member 24 being closed and the valve stem 32 therefore projecting somewhat farther from the control body I8 than is illustrated in this view.

A flame is provided at the pilot burner 54 by igniting the fuel flowing therefrom and, after suilicient time has elapsed for the thermocouple 52 to become heated, the button 42 is manually depressed to bring the armature 40 into engagement with the pole faces of the magnet 38. As the winding 50 is now energized by the current generated by the thermocouple 52, the armature 40 is retained in its attracted position and the reset stem 48 remains in the extended position shown in full lines of the drawings, Figs. 2 and 3. As the plunger 58 of the electric clock is in its retracted position, the resetting operation merely places the lever device 60 in position to be operated by the plunger 58 and does not aifect the closed position of the valve member 24. However, due to the change in position of the plate 62, the spring 10 which is associated with the electromagnetic safety device 20 is somewhat compressed at this time.

The valve member 24 is moved off its seat against the bias of the valve spring 34 by movement of the clock plunger 58 to its extended position, shown in full lines in Fig. 2 of the drawing. This movement of the lever device 60 to the right, as viewed in Fig. 2, causes a rotation thereof about the line A-A (Fig. 1) to the full line position shown in Fig. 2 of the drawing. It is apparent that since the screw 84, forming the pivot of the plate 62, and the reset stem 48 are both fixed, a rotation of the plate on an axis including the pivot and the' reset stem must occur. This rotation of the plate 62 to the fullline position (Fig. 2) and the corresponding movement of the valve stem 32 causes the valve member 24' to be moved away from its seat 26 to open position against the bias of the valve spring 34 The fuel which flows from the inlet 28 to the outlet 30 by way of the valve seat 26 is ignited at the main burner 3| by the pilot burner 54 when the apparatus is in running condition. At the expiration of the time period set by the clock, the plunger 58 thereof is automatically retracted to the broken line position shown in Fig. 2. This movement of the plate 52 is a rotation on the same line AA (Fig. 1), that is, on an axis including the pivot 84 and the reset'stem 48. Consequently, the valve member 24 is moved by the valve spring 34 into closed position and the flow of fuel to the main burner 3| is shut off. It will be apparent that the described control of the main burner 3i could be conducted through the agency of other condition controlling devices as previously indicated, as well asby the clock of this embodiment.

If the pilot burner 64 becomes extinguished during normal running operation of the main burner 8|, then the thermocouple 52 will cease to energize'the winding of the magnet 88. The armature 48 will be moved by the pressure of the spring 16 assisted by some force from the valve spring 84 to its released position, and the plate 62 will be rotated about the line BB (Fig. 1), that is, on an axis including the pivot 64 and the plunger 68. Hence, the valve member 24 is moved to its closed position by the valve spring 84 as the plate 62 is now in the broken line position shown in Fig. 2 of the drawing. The apparatus cannot be again placed in normal running operation until the pilot burner 54 is again lighted and the described sequence of operations conducted.

The modified forms shown in Figs. 4-6 and in Figs. 7 and 8 of the drawing are similar in function to the preferred embodiment previously described although somewhat diiferent in the details of construction. In Figs. 4-6 there is disclosed a control apparatus having an electromagnetic safety device 28, a control means l8 and an actuating means 22 similar in all respects to those described in connection with Figs. 1-3. The lever.

device of this embodiment is in two separate parts and comprises a first lever 14 in the form of a narrow strip of material having depending lugs 16 on opposite sides thereof and located intermediate its ends. The lugs I6 fit within a channel-shaped bracket 18 projecting upwardly from an annular plate 88 which is secured to the control body H by the cap 31 of the electromagnetic safety device 20. A pin 82- extends transversely through the bracket 18 and the lugs 16 and provides a pivot for the lever 14.

One end of the lever 14 is adapted to overlie the reset stem 48 and the opposite end thereof is positioned intermediate the valve stem 32 and plunger 58 and is provided with a depending lip 84. The reset stem of this embodiment may be provided with a ferrule 85 instead of a pointed end as in the previously described form. Extending transversely across the underside of the first lever I4 adjacent the lip 84 is a second lever 86. r This second lever is of sufilcient length to overlie at one end the plunger 58 and at the other end the valve stem 32.

The second lever 86 is adapted to be pivoted intermediate its ends on the first lever I4 and will, therefore, rock in an are substantially perpendicular to the'arc of rotation of the first lever 14. The pivot of the second lever 86 may take the form of a in 88 rigidly mounted on the lever 86 and extending loosely through an elongated aperture 86 formed in the lever 14. The lever 86 is further provided with a raised portion 82 of rounded contour extending transversely thereof and adapted to contact with the underside of the lever 14 to facilitate rocking movement.

The lever 14 is yieldably urged into engage-v ment with the ferrule 85 by a coil spring 84 which extends from the control body l4 into engagement with the underside of the lever 14 between the pivot 82 therefor and the second lever 86. It will be observed that the levers l4 and 86 are positioned by the spring 84 so that the second lever 86 does not engage either the plunger 58 or the valve stem 32 until the reset stem 48 is in the extended position. The operation of this modification is, however, substantially equivalent to that of the previously described embodiment insofar as the lever device provides for both 'condition and safety control through the agency of a single control device exemplified by the valve member 24.

In the operation of the embodiment shown in Figs. 4-6 the resetting movement of the reset stem 48 will rotate the first lever 14 on its pivot 82 and bring the second lever 86 into proximate relation with the plunger 58. As in the previously described embodiment, Figs. 1-3, this resetting movement does not affect the position ofthe valve member 24 which remains closed under its bias. After the pilot burner is lighted and the thermocouple sufliciently heated to generate electric current and hold the armature in engagement with the pole faces of the magnet, the apparatus is in condition for control by the actuating means 22, such as the aforementioned elec- I tric clock. 7

Thus, extension of the plunger 56 by operation of the clock will serve to rotate the lever 86 about its pivot and cause the valve stem 32 to be actuated to open the valve member 24 against its bias. After the main burner 3| has operated for the set period, the plunger 58 will retract and cause the second lever 86 to be returned to its former position by the valve stem 22 under the bias of the valve spring 34. The valve member 24 being closed, further flow of fuel to the main burner 8! is cut of! untfl the clock again operates the plunger 58 for further operation of the main burner 8|.

In the event that the pilot burner 54 becomes extinguished the thermocouple will cool and cease to generate current causing the armature 48 to become disengaged from the pole faces of the magnet 38 by rotation of the lever 14 clockwise under the bias of the spring 84. As the first lever I4 is thus rotated on its pivot, the second lever 86 is moved coincidentally to its initial'position out of operative engagement with the plunger 58. Consequently, any further movement of the plunger 58 will not affect the posi-- tion of the second lever 86 and the valve member 24 will remain closed.

In the embodiment shown in Figs. '7 and 8 of the drawings, the lever device also takes the form of two parts which are arranged in a somewhat different manner from those disclosed in Figs. 4-6. In this third arrangement the actuating means 22, the control means I8 and the electromagnetic safety means 28, are located on the same. longitudinal axis, thus departing from the triangular arrangement of the two previous embodiments. The first lever 86 is somewhat boatshaped in plan and is pivoted at the wider portion intermediate its ends. The pivot is similar to that of Figs. 46 and comprises a pin 88 carried by a bracket 18 and extending through depending lugs I08 formed on opposite sides of the lever 86.

It will be apparent that the bracket 18 may be carried by an annular plate 68 which is secured to the control body 14 by a cap 31. The lever 86 overlies at one end the reset stem 48 and, at the other end, terminates intermediate the plunger 58 and the valve stem 32.

Due to the axial arrangement of the control parts in the embodiment shown in Figs. 7 and 8, the second lever 86 is located on substantially the same longitudinal axis as the lever 86. This second lever 86 is pivoted on the first lever 86 in a manner similar to that of the previous embodiment, that is, by the provision of a pin 88 projecting from lever 86 through an aperture in the lever 86, together with a raised portion 82 formed on the lever 86 and adapted to contact with the underside of the lever 86. The second lever II also overlies the valve stem 32 and the plunger '8, as in the previous embodiment, and is maintained out of proximate relation with the plunger It by a spring ll located in the same relative position with the pivot SI and the adjacent end of the second lever It as previously described.

As it is apparent that the operation of the embodiment shown in Figs. 7 and 8 may be identical in all respects with that described in connection with Figs. 4-6, further description at this point is deemed unnecessary. The novel lever device of this invention has been described and shown in three different embodiments thereof all of which operate upon the same general principles and disclose the flexibility of arrangement possible, both in the lever device itself and in the arrangement of the control apparatus.

It will be understood that many changes can be made in the arrangement and combination of parts and in the details of construction herein disclosed within the scope of the appended claims without departing from the spirit of the invention.

I claim:

1. In a control device, the combination of control means movable between open and closed positions and being biased to said closed position, a lever device adapted to be positioned for operative engagement with said control means for opening the same upon rotation of said device from said position, a pivot about which said device is adapted for rotation, electromagnetic safety means having an attracted and a released position and being operatively engageable with said device in said attracted position for positioning the same relative to said control means about said pivot, actuating means having an operative position in which it is adapted to act upon said device when positioned for causing rotation thereof on said pivot, thereby to cause opening of said control means, and means efl'ective while said actuating means remains in said operative position for causing rotation of said device on said pivot when said safety means assumes a released position for closing said control means under its bias.

2. In a control device, the combination of control means movable between open and closed positions and being biased to said closed position, a lever device adapted to be positioned for Operative engagement with said control means for opening the same upon rotation of said device from said position, a pivot about which said device is adapted for rotation, electromagnetic safety means including an armature movable between attracted and released positions, means for resetting said armature to attracted position and positioning said device relative to said control means about said pivot, said pivot being located intermediate the points of engagement of said control means and said resetting means with said device, actuating means having an operative po-' sition in which it is adapted to act on said device when positioned for causing rotation thereof on said pivot, thereby to cause opening of said control means, and yieldable means eiIective while said actuating means remains in said operative position for rotating said device on said pivot when said armature assumes a released position to effect closing of said control means under its bias.

3. In a control device, the combination of control means movable between open and closed positions and being biased to said closed position, a lever device adapted to be positioned for operative engagement with said control means for opening the same upon rotation of said device from said position, a pivot about which said device is adapted for rotation, electromagnetic safety means including an armature movable between attracted and released positions, means for resetting said armature to attracted position and engageable with said device at a point spaced from the point of engagement of said control means therewith for positioning said device relative to said control means about said pivot, said pivot being located intermediate the points of engagement of said control means and said resetting means with said device, actuating means having an operative position in which it is adapted to act on said device at a point spaced from the points of engagement of said control means and resetting means therewith when positioned for causing rotation of said device on said pivot, thereby to cause opening of said control means, and yieldable means eflfective while said actuating means remains in said operative position for rotating ,said device on said pivot when said armature assumes a released position to effect closing of said control means under its bias.

4. In a control apparatus, the combination of control means movable between open and closed positions and being biased to said closed position, a lever device adapted to be positioned for operative engagement with said control means for opening the same upon rotation of said device from said position, electromagnetic safety means having an attracted and 9. released position and engageable with said device in said attracted position at a point spaced from the point of enagement between said device and control means for positioning said device for said operative engagement, a pivot for said device located at a point spaced from the points of engagement of said safety means and control means therewith, actuating means having an operative position in which it is adapted to act upon said device when positioned for rotating the same' on an axis including said pivot and said safety means engagement point for opening said control means, and means for causing rotation of said device on an axis including said pivot and the point of engagement of the device and said actuating means in said operative position of said actuating means when said safety means assumes a released position to eilect closing of said control means under its bias.

5. In a control apparatus, the combination of control means movable between open and closed positions and being biased to said closed posi tion, a lever device adapted to be positioned for operative engagement with said control means, electromagnetic safety means having an attracted and released position and engageable with said device in said attracted position for positioning the same for said operative engagement, a pivot for said device, actuating means having an operative position in which it is adapted to engage and act upon said device when positioned, the engagement of said actuating means and electromagnetic means with said device being at spaced points forming triangular relationship to the point of engagement of said control means therewith and enclosing said pivot therewithin, said actuating means being adapted in said operative position thereof to rotate said device on an axis including said pivot and the point of engagement of said safety means in said attracted position thereof for opening said control means, and yieldable means operable on said device axially of said electromagnetic means for causing rotation of said device on an axis including said pivot and the engagement point of said actuating means in said operative position thereof when said safety means assumes a released position to effect closing of said control means under its bias.

6. In a control apparatus, the combination of control means movable between open and closed positions and being biased to said closed position, a lever device adapted to be positioned for operative engagement with said control means, electromagnetic safety means including an armature movable between attracted and released positions, means adapted to engage said device on the same side of said device as said control means for resetting said armature to attracted position and positioning said device for said operative engagement,-a pivot for said device located on the opposite side thereof from said resetting and control means, actuating means movable between operative and inoperative positions and being adapted to engage said device when positioned on the same side as said resetting and control means, the engagement of said actuating and resetting means with said device being at spaced points forming triangular relationship to the point of engagement of said control means therewith and enclosing said pivot therewithin, said actuating means being adapted in said operative position thereof to rotate said device when positioned on an axisincluding said pivot and the engagement point of said resetting means in said attracted position of said armature for opening said control means, and yieldable means operable on said device axially of said resetting means for causing rotation of said device on an axis including said pivot and the engagement point of said actuating means in said operative position thereof when said armature assumes a released position to efiect closing of said control means under its bias.

7. In a control apparatus, the combination of control means movable between open and closed positions and being biased to said closed position; electromagnetic safety means including an armature movable between attracted and released positions; actuating means for causing movement of said control means between closed and open positions when said armature is held in attracted position; a single triangular lever adapted to be engaged on the same side and adjacent two apices thereof respectively by said control means and said actuating means; said safety means being positioned adjacent the third apex of said lever and on the said same side thereof; yieldable means engageable with said lever adjacent said third apex and on the opposite side thereof from said safety means for causing movement of said armature to released position; a reciprocable element for resetting said armature to attracted position and engageable with said lever adjacent said third apex for overcoming said yieldable means; and a pivot engaging said lever on the said opposite side and located substantially equidistant of the apices thereof; said yieldable means being efiective for rotating said lever about an axis including said pivot and said actuating means engagement apex to allow said control means to close under its bias in the event that said armature moves to released position; said actuating means being efiective for rotating said lever about an axis including said pivot and said resetting means engagement apex to cause said 10 control means to open and close in the event that said armature is held in attracted position.

8. In a control device, the combination of control means movable between open and closed positions and being biased to said closed position, a single triangular lever engageable adjacent one apex thereof by said control means,

effective for rotating said lever about an axis including said pivot and said actuating means apex to allow said control means to close under its bias in the released position of said armature, said actuating means being effective for rotating said lever about an axis including said pivot and said safety means apex in the attracted position of said armature in one direction to open said control means against its bias and in another direction to allow said control means to close under it bias.

9. In a control apparatus, the combination of control means movable between open and closed positions and being biased to closed position, electromagnetic safety means including an ar mature movable between attracted and released positions, means for resetting said armature to attracted position, actuating means for causing movement of said control means between closed and open positions when said armature is held in attracted position, a first lever pivoted inter mediate the ends thereof, one end of said lever being engageable with said resetting means for rotation thereby from an initial position during said resetting operation, and the opposite end being located intermediate said actuating and control means, a second lever pivoted intermediate the ends thereof on said first lever, one end of said second lever being engageable with said control means and the opposite end being engageable with said actuating means, said second lever being movable bodily by said first lever when the latter is rotated by said resetting means thereby to position said second lever for operative engagement with said actuating means and said control means, said actuating means being adapted to rotate said second lever while so positioned in operative engagement therewith for opening said control means against the bias thereof, and yieldable means for biasing said first lever against said rotation by said resetting means and being eifective for rotating said first lever toward said initial position thereof when said armature assumes a released position to disengage said second lever and actuating means, thereby causing said control means to close under the bias thereof.

10. In a control device, the combination of control means movable between controlling positions and being biased to one of said positions, a lever device adapted to be initially positioned in operative engagement with said control means for causing movement thereof between said positions upon rotation of said device from said position, a pivot for said device, positioning means operative fOr rotating said device on said pivot to said initial position and relative to said 11 control means, actuating means adapted to assume a position in which it is effective for rotating said device on said pivot from said initial position when said positioning means is operative and for causing movement 01. said control 5 means against its bias to another said controlling position, and means for rotating said device on said pivot to said initial position and causing movement of said control means to said one controlling position when said positioning means is 10 inoperative and while said actuating means remains in said position and thereby rendering said actuating means ineffective.

HAROLD W. RICE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,780,093 Newell Oct. 28, 1930 2,008,842 Sloyen July 23, 1935 2,019,008 Hauser Oct. 29, 1935 2,074,696 Johnson Mar. 23, 1937 2,118,886 Joesting May 31, 1938 2,299,286 Wantz Oct. 20, 1942 2,302,624 Gallagher Nov. 17, 1942 2,303,672 Wantz Dec. 1, 1942 2,354,814 Joesting Aug. 1, 1944 1 Harris Nov. 14, 1944 2,383,401 Manta Aug. 21, 1945

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