US2621621A

US2621621A - Apparatus for closing interlocking seams

Info

Publication number: US2621621A
Application number: US243553A
Authority: US
Inventors: Harry S Kaiser
Original assignee: H S KAISER Co
Current assignee: H S KAISER Co
Priority date: 1951-08-24
Filing date: 1951-08-24
Publication date: 1952-12-16
Anticipated expiration: 1969-12-16

Description

Dec. 16, 1952 H. s. KAISER APPARATUS FOR CLOSING INTERLOCKING SEAMS 4 Sheets-Sheet 1 Filed Aug. 24, 1951 INVENTOR. 2 7 i Mas 6.2

Dec. 16, 1952 H. s. KAISER APPARATUS FOR CLOSING INTERLOCKING SEAMS 4 sheetsf shaet 3 Filed Aug. 24, 1951 Dec. 16,1952

Filed Aug. 24, 1951 H. S. KAISER APPARATUS FOR CLOSING INIERLOCKING SEAMS 4 Shees=Siieet 4 Patented Dec. 16, 1952 APPARATUS FOR- CLOSING INTERLOCKING SEAMS Harry 8. Kaiser, Chicago, Ill., assignor to H. S. Kaiser Company, Chicago, 111., a corporation of Illinois Application August 24, 1951, Serial No. 243,558

'7 Claims.

This invention relates to apparatus for closing interlocking seams on sheet metal articles, such as sheet metal pipes and the like.

In the fabrication of sheet metal pipes and the like interlocking seams are utilized and such seams are usually closed by manually hammering the same with mallets or the like. In this connection the sheet metal pipe is placed over a rail having a longitudinal groove with the open interlocking seam overlying the groove. The seam is then manually hammered closed in the groove with; mallets. Then the closed seam is ordinarily manually pricked at intervals by a prick punch to prevent the seam from coming apart. The hammering necessary for this manual method of closing the interlocking seam is slow, tedious and time consuming, requires considerable personal skill, often results in poor, uneven and unsightly seams, and creates considerable noise resulting in the usual nerve wracking din found in sheet metal shops.

The principal object of this invention is to provide an apparatus for closing interlocking seams on sheet metal articles, such as sheet metal pipes, ducts and the like, wherein such seams may be quickly and uniformly closed, wherein hammering and its resulting shortcomings are eliminated, wherein such seams are rolled and pressed to close the same to provide a uniform and firmly engaged seam, wherein personal skill is largely eliminated and wherein noise is maintained at a minimum.

The apparatus of this invention for closing interlocking seams on sheet metal articles includes an elongated lower rail having a longitudinally extending groove on its upper surface and adapted to receive a sheet metal article having an open interlocking seam overlying the groove, along with an elongated upper rail parallel to and spaced from the lower rail and having spaced facing upper and lower tracks. A carriage having wheels located between the spaced facing upper and lower tracks is normally suspended by the lower track for rolling movement therealong. The carriage vertically movably carries a member below the upper rail which in turn carries a roller protruding downwardly therefrom. Motor means are also carried by the carriage and are connected to the member for raising and lowering the member and hence the roller carried thereby. Control means for the motor means are operative normally to raise the member to space the roller above the lower rail and are also operative to raise the carriage and lower the member to cause the wheels of the carriage r'ollinglyto engage the article uniformly to close the same.

i The motor means may be a fluid motor means having an expansible chamber and the control means may include a valve means for controlling the flow of fluid to and from the expansible chamber for closing the interlocking seam as the carriage is rolled along the upper rail. The valve means may also regulate the pressure of the fluid admitted to the expansible chamber in accordance with the thickness and kind of metal forming the seam so that proper closing forces may be applied to the seam. Prick points may be located in the groove in the lower rail automatically to prick the interlocking seam as it is being closed by the roller. Guide bars may also be adjustably carried by the lower rail for supporting the overhanging portions of the sheet metal articles resting on the lower rail. A pair of clamping devices may also be slidably carried by the rail for clamping the sheet metal articles to the rail as the seams thereof are being closed. These clam-ping devices may be automatically released by the carriage when the seam closing operation is completed. The two rails may be firmly supported in such a manner that the sheet metal device, such as a pipe or the like, may be received over and removed from one end of the lower rail.

Further objects of this invention reside in the details of construction of the apparatus for closing interlocking seams and in cooperative relationships between the component parts thereof.

Other objects and advantages of this invention will become apparent to those skilled in the art upon reference to the accompanying specification, claims and drawings, in which:

Fig. 1 is a side elevational view of the apparatus of this invention;

Fig. 2 is a horizontal sectional view taken substantially along the line 2-2 of Fig. 1;

Fig. 3 is an enlarged vertical sectional view taken substantially along the line 33 of Fig. 2;

Fig. 4 is an enlarged partial sectional view taken substantially along the line 44 of Fig. 5;

Fig. 5 is an enlarged sectional View taken substantially along the line 55 of Fig. 4 and showing the roller raised;

Fig. 6 is a partial sectional View similar to Fig. 5, but showing the roller lowered;

Fig. '7 is an enlarged perspective view of the right end of the apparatus as illustrated in Fig. 1;

Fig. 8 is an enlarged perspective view of a clamping device utilized in the apparatus;

Figs. 9 and 10 are side elevational views of the clamping device illustrated in Fig. 8, Fig. 9 showing the clamping device in clamping position and Fig. 10 showing the clamping device in released position;

Fig. 11 is an enlarged perspective view of the lower rail showing the guide bars;

Fig. 12 is a perspective view of a sheet metal article such as a sheet metal pipe or duct whose interlocking seam is closed by the apparatus of this invention;

Figs. 13, 14 and 15 are enlarged partial sectional views showing the manner in which the interlocking seams of the sheet metal article are closed by the apparatus of this invention.

Referring first to Figs. 1 and 2 of the drawing, the apparatus includes a substantially horizontal upper rail II and a substantially horizontal lower rail I2. The upper rail II suspends a carriage I3 for rolling movement therealong and the carriage I3 includes mechanism for closing an interlocking seam I I in a sheet metal article I5, such as a sheet metal pipe or duct which is applied over the lower rail I2.

The lower rail I2 may be in the form of an I beam and it has an upper surface I! provided with a longitudinally extending groove l8 in which the interlocking seam I4 is closed. One end of the lower rail I2 is secured by a suitable bracket I9 to a vertical supDOrt, such as a wall 20. Another vertical support 2| is secured to the lower rail I2 and extends between it and the floor 22, the bracket I9 and support 2| operating to support the lower rail I2 in a substantially horizontal position.

The interlocking seam Id of the sheet metal article [5 is illustrated in more detail in Figs. 13 to 15 and it includes a p-air of overlapping or interlocking portions 24 and 25. These interlocking portions 25 and 25, in open condition, are disposed over the groove I8 in the lower rail I2, as illustrated in Fig. 13. These interlocking portions are then rolled together in the groove I8 for the purpose of closing the same, as illustrated in Fig. 14. The groove I8 is preferably provided with a plurality of longitudinally spaced prick points 26 so that as the interlockin seam It is closed the prick points 2 6 automatically prick the closed seam, as illustrated at 21 in Fig. 15, for the purpose of locking the same together.

The upper rail I I may also be in the form of an I beam and the upper portion of the rail forms downwardly facing tracks 29 on each side of the web of the I beam. A pair of angle members 39 are secured to the web of the upper rail by means of bolts 3| and these angle members form upwardly facing tracks 32. Thus the upper rail is provided with spaced facing upper and

lower tracks

29 and 32, respectively. The upper rail II has one end secured to the vertical wall or support by means of a bracket 33. The other end of the upper rail I l is provided with a bracket 34 which in turn is connected by turn buckles 35 and cables 36 to brackets 31 secured to a suitable support, such as a sealing 37. In this way both ends of the upper rail 'I I are firmly supported to support the upper rail II in a substantially horizontal position.

As illustrated in Figs. 1 and 7, the outer end of the upper rail I I has a bracket 38 suitably secured to the upper surface thereof. The bracket 33 carries a pin 39 which in turn carries a pair of levers ill which are secured together by pins III, 52 and 43. A cable 44 is connected to the pin 42 and extends upwardly over a pulley 45 which terminates in a counterweight 46. The counterweight 46 normally holds the levers 49 in an elevated position, as illustrated in broken lines in Fig. 1. When, however, the levers 40 are swung downwardly to the solid line position illustrated in Fig. 1, the pin 43 slides over and engages a pair of projections 59 on the underside of the lower rail I2 and these projections maintain the levers in that position against the action of the counterweight. Thus, the levers 40 operate firmly to support the outer end of the lower rail l2, but yet may be moved away from the lower rail I2 to allow application and removal of the sheet metal article I5 to and from the lower rail I2. To assist in the manipulation of the levers 40, the levers All carry a pair of brackets 4'! and 48 having pins 49 extending therebetween to form handles for moving the levers,

As shown in more detail in Figs. 4 to 5. the carriage I3 includes a pair of side plates 5|, the upper ends of which are secured to a top plate 52 by'means of bolts 53, orthe like. The top plate 52 is disposed above the upper rail 1 I. The side plates 5| also carry an intermediat plate 54 disposed below the upper rail II. Two pairs of Wheels 55, having flanges 55, are interposed between the facing upper and

lower tracks

29 and 32, these wheels 55 being journalled in suitable bearings 51- secured to the side plates 5| by bolts 58 or the like. The wheels 55 normally engage the lower tracks 32, as illustrated in Figs. 4 and 5, to suspend the carriage I3. for rolling movement along the upper rail I I.

The lower portions of the side plates 5I of the carriage I3 are provided with a pairof vertically arranged guide blocks Gil for vertically slidably mounting a member therebetween. The member includes a pair of downwardly extending portions BI engaging the side plates 5I and the guide blocks 60 and an upper transverse part 62. The downwardly extending portions 6i carry bearings 63 which in turn rotatably mount a shaft 64 carrying a roller 65. Thus, the member is mounted for vertical movement in the carriage I3 and, hence, carries and, vertically moves the roller 65 protruding downwardly therefrom. The side plates 5I may be provided with slots 66 for accommodating this vertical movement of the member and the roller 65.

Motor means are carried by the carriage I3 for raising and lowering the member and, hence, the roller 65. The motor means may be of the fluid type having an expansible chamber. In this respect, the motor means may include an air cylinder 63 having a suitable piston or diaphragm therein forming the expansible chamber. The cylinder 68 is connected by bolts (9 to the intermediate plate 54 of the carriage. The piston or diaphragm within the cylinder 53 operates a piston rod I0 which is. secured by a suitable bracket H. to the transverse portion 82 of the member which carries the roller 65. The fluid motor means may include suitable spring means in the cylinder for normally raising the member and the roller 65. When, however, fluid is supplied to the cylinder 68, the piston rod I0 and. hence, the roller 65 move downwardly against the action of the spring means. The force at which the roller 65 moves downwardly is dependent upon the pressure of the fiuidin the expansible chamber of the motor means.

Fluid, such as air, is supplied to the motor means through a pressure regulator I3 which is adjustable by means of a suitable handle I4, the pressure of the fluid being indicated by a suitable gauge I5 associated with the pressure regulator. Air, after it passes through the pressure regulator I3, is conducted by a conduit 16 to a valve 11 having an operating mechanism I8 controlled by a handle I9. The valve 11 supplies air to, or exhausts air from; the expansible chambers within the motor means 58 through conduits 80 extending through openings 8I in one of the side plates 5 I, as illustrated in Fig. 1. When the valve 11 is operated to one position by the handle I9 air is exhausted from the cylinders 68 to raise the roller 65. When the valve TI is moved to the op posite position by the handle I9, air, under pressure, is admitted to the cylinders 60 to force the roller 65 downwardly, as illustrated in Fig. 6. When the roller 55 is thus forced downwardly, the carriage by reaction is raised so that the wheels 55 engage the upper tracks 29, as illustrated in Fig. 6. Thus, there is a direct reaction force between the upper tracks 29 and the lower rail I2 and while this force is being applied, the carriage may be longitudinally rolled along by reason of the wheels 55 engaging the upper tracks 29 and the roller 65 engaging the interlocking seam I4. Thus, as the carriage I3 is rolled along the upper rail II the roller 65 operates to close the interlocking seam I4. The pressure regulator I3 may be adjusted to regulate the amount offorce applied in closing the interlocking seam I4 so as to adapt the apparatus to different types of metal and difierent thicknesses of metal utilized in the interlocking seam of the article. When the pressure is released by manipulating the valve 11, the roller 65 is raised and the wheels 55 again engage the lower tracks 32 to allow the carriage I3 to be rollingly suspended by the upper rail I I with the roller 65 raised above the closed interlocking seam I4.

The carriage I3 may be rolled along the upper rail during idle periods and during periods when the seam is being closed by any suitable means. For example, the side plates 5| of the carriage I3 may be provided with a pair of brackets 83 having handles 84 extending outwardly therefrom. These handles may be grasped for rolling the carriage.

When the article I5, having the interlocking seam I4 to be closed, is placed over the lower rail I2, it is preferably clamped in proper position on the lower rail I2 by a pair of clampin devices 81, as illustrated in Fig. 1. These clamping devices are shown in more detail in Figs. 8 to 10. Each clamping device 81 includes a member 88 slidably carried on the upper surface I! of the lower rail I2 by flange 89 extending underneath the upper surface. A pair of brackets 99 are provided with flanges 9I for securing the same to the member 88. A clamping lever 92 is pivoted at one end by means of a pivot pin 93 to the brackets 90. The other end of the clamping lever 92 carries a screw 94 which is locked in place by

lock nuts

95 and 96. The screw 94 in turn carries aplate 91 which in turn carries a pair of depending arms 98 having clamping members 99 on the lower ends thereof. The clamping members 99 engage the article I5 for clamping the same to the upper surface ll of the lower rail I2. The clamping lever 92 is operated by toggle levers. One of the toggle levers I00 is pivoted to the brackets 90 by a pivot pin IOI. The other toggle lever includes a pair of levers I02 pivoted to the toggle lever I00 by a pivot pin I03 and to the clamping lever 92 by a pivot pin I04. One of the toggle levers I02 is provided with a projection I05 for engaging the upper edge of the clamping lever 92 whenthe toggle levers are in clampin position, as illustrated in Fig. 9. When the pivot pins I0 I, I09 and I04 are in substantial alignment, as illustrated in Figs. 8 and. 9, the clamping members 99 are held in contact with the sheet metal article I5 for clamping the same to the upper surface I! of the lower rail I2. When, however, the toggle lever I09 is tilted backwardly, asillustrated in Fig. 10, the toggle levers operate to move the clamping lever 92 upwardly to release the sheet metal article I5. The toggle lever I00 carries a suitable tripping mechanism to be engaged by the carriage I3. This tripping mechanism includes a spring I06 connected by arms I01 to a washer I08 and by a rod I09 to a washer IIO. A nut I I I clampsthe washers I08 and I I0 against the toggle. lever I00 for securing the tripping device in place thereon.

When the sheet metal article I5 is placed on the lower rail I2 to have its interlocking seam I4 closed, it is clamped in place by the clamping devices 31, as illustrated in Fig. 1, then the carriage I 3 is manipulated for the purpose of closing the interlocking seam l4 in the sheet metal article I5 and when the closing operation is completed the carriage is moved to one extremity to engage the tripping device I 00 for releasing its clamping member and as the carriage is continued in its movement the clamping device is moved out of the way and the seam closed to the very end. Then the carriage I3 is moved to the other end of the sheet metal article I5 and the other clampin device is released and moved out of the way and the seam completely closed at the other end.

To assist in supporting the sheet metal article I5 on the lower rail I2, the lower rail is provided with an adjustable guide bar arrangement illustrated in more detail in Figs. 1, 2 and 11. Here two pairs of levers II5 are connected by hinges II6 to the web of the lower rail I2. The outer ends of these levers I I5 are connected by hinges I20 to a pair of bars II9 which in turn rigidly carry guide bars I I8 having inwardly flared ends I2I. In this way the guide bars II8 are adjustably mounted on the lower rail I2 and may be swung inwardly and outwardly from the lower rail I2. The upper surfaces of these guide bars IIB are in substantial alignment with the upper surface I1 of the lower rail I2 and when the guide bars II8 are swung outwardly, as illustrated in Figs. 2 and 11, they operate to support the outer portions of the sheet metal article I5 so as to prevent accidental opening of the open seam I4 when the sheet metal article is applied to the lower rail I2. Because of the adjustable mounting of the guide bars II8, they operate effectively to. support almost any size of sheet metal article.

While for purposes of illustration one form of this invention has been disclosed, other forms: thereof may become apparent to those skilled in the art upon reference to this disclosure and, therefore, this invention is to be limited only by the scope of the appended claims.

I claim as my invention:

1. Apparatus for closing interlocking seams in sheet metal articles comprising, an elongated lower rail having a longitudinally extending groove on its upper surface and adapted to receive a sheet metal article having an open interlocking seam overlying the groove, an elongated upper rail parallel to and spaced from the lower rail and. having spaced facing upper and lower tracks, a carriage having wheels located between the spaced facing upper and lower tracks and normally suspended by the lower track for rolling movement therealong, a member vertically movably carried by the carriage below the upper rail and having a roller carried thereby and protruding downwardly therefrom, motor means carried by the carriage and connected to the member for raising and lowering the member and hence the roller carried thereby, and control means forthe motor means operative normally to raise the member to space the roller above the lower rail and operative to raise the carriage and lower the member to cause the wheels of the carriage r011- ingly to engage the upper track of the upper rail and. the roller rollingly to engage the .open interlocking seam of the sheet metal article overlying the groove in the lower rail for closing the same as the carriage is rolled along the upper rail.

2. Apparatus for closing interlocking seams in sheet metal articles comprising, an elongated lower rail having a longitudinally extending groove on its upper surface and adapted to receive a sheet metal article'having an open interlocking seam overlying the groove, an elongated upper rail parallel to and spaced from the lower rail and having spaced facing upper and lower tracks, a carriage having wheels located between the spaced facing upper and lower tracks and normally suspended by the lower track for rolling movement therealong, amember vertically movablycarried by the carriage below the upper rail and having a roller carried thereby and protrud ing downwardly therefrom, fluid motor means including an expansible chamber carried by the carriage and connected to the member for raising and lowering the member and hence the roller carried thereby, control means for the fluid motor means, including valve means for controlling the flow of fluid to and from the expansible chamber ofthe fluid motor means, operative normally to raisenthe member to space the roller above the lower rail and operative to raise the carriage and lower the member to cause the wheels of the carriagerrollingly to engage the upper track of the upper rail and the roller rollingly to engage the open interlocking seam of the sheet metal article overlying the groove in the lower rail for closing the same asthe carriage is rolled along theupperrail.

3. "Apparatus for closing interlocking seams in sheet "metal articles comprising, an elongated lower rail having a longitudinally extending groove on its upper surface and adapted to receive a sheet metal article having an open interlocking seam overlying the groove, an elongated upper rail parallel to and spaced from the lower rail and having spaced facing upper and lower tracks, a carriage having wheels located between the spaced facing upper and lower tracks and normally suspended by the lower track for rolling movement therealong, a member vertically movably carried by the carriage below the upper rail and having a roller carried thereby and protruding downwardly therefrom, fluid motor means including an expansible chamber carried by; the carriage and connected to the-member for raising and lowering the member and hence the roller carried thereby, control means for the fluid motor means, including valve means for controlling the flow of fluid to and from the exp-ansible chamber of the fluid motor means, operative normallyto raise the member to space the roller above the lower rail and operative to raisethe carriage and lower the member to cause the wheels of the carriage rollingly to engage the upper track of the upper rail and the roller rollingly to engage the open interlocking seam of the sheet metal article overlying th groove in the lower rail for closing the same as the carriage is rolled along the upper rail, said valve means of the control means also controlling the fluid pressure in the expansible chamber of the fluid motor means to regulate the force with which the roller rollingly engages the interlocking seam of the sheet metal article.

4. Apparatus for closing interlocking seams in sheet metal articles comprising, an elongated lower rail having a longitudinally extending groove on its upper surface and adapted to receive a sheet metal article having an open interlocking seam overlying the groove, an elongated upper rail parallel to and spaced from the lower rail and having spaced facing upper and lower tracks, a carriage having wheels located between the spaced facing upper and lower track and normally suspended by the lower track for rolling movement therealong, a member vertically movably carried by the carriage belowthe upper rail and having a roller carried thereby and protruding downwardly therefrom, motor means carried by the carriage and connected to the member for raising and lowering the member and hence the roller carried thereby, control means for the motor means operative normally to raise the member to space the roller above the lower rail and operative to raise the carriage and lower the member to cause the wheels of the carriage rollingly to engage the upper track of'the upper rail and the roller rollingly to engage the open interlocking seam of the sheet metal article overlying the groove in the lower rail for closing the same as the carriage is rolled along the upper rail, and prick point carried by the lower rail within the longitudinally extending groove for pricking the interlocking seam of the sheet metal article as it is closed by the roller.

5. Apparatus for closing interlocking seams in sheet metal pipes and the like comprising, an elongated upper rail having spaced facing upper and lower tracks, means for supporting the upper railadjacent its ends in a horizontal position, an elongated lower rail parallel to and spaced from the upper rail and having a longitudinally extending groove on its upper surface and adapted to receive a sheet metal pipe or the like having an open interlocking seam overlying the groove, means adjacent one end of the lower rail for sup-porting the lower rail in a horizontal position to allow the sheet metal pipe or the like to be received over and removed from the lower rail, a movable clamp for the other end of the lower rail carried by the upper rail for supporting said other end of the lower rail when in oneposition and allowing the sheet metal .pipe or the like to be received over and removed from said end of the lower rail when in another position, a carriage having wheels located between the spaced facing upper and lower tracks and normally suspended by the lower track for rolling movement therealong, a member vertically movably carried by the carriage below the .upper rail and having a roller carried thereby and protruding downwardly therefrom, motor means carried by the carriage and connected to the member for raising and lowering the member and hence the roller carried thereby, and control means for the motor means operative normally to raise themember to space the roller above the lower rail and operative to raise the carriage and lower the member to cause the wheels of the carriage rollingly to engage the upper track of the upper rail and the roller rollingly to engage the open interlocking seam of the sheet metal pipe or the like overlying the groove in the lower rail for closing th same as the carriage i rolled along the upper rail.

6. Apparatus for closing interlocking seams in sheet metal articles comprising, an elongated lower rail having a longitudinally extending groove on its upper surface and adapted to receive a, sheet metal article having an open interlocking seam overlying the groove, an elongated upper rail parallel to and spaced from the lower rail and having spaced facing upper and lower tracks, carriage having wheels located between the spaced facing upper and lower tracks and normally suspended by the lower track for rolling movement therealong, a member vertically movably carried by the carriage below the upper rail and having roller carried thereby and protruding downwardly therefrom, motor means carried :by the carriage and connected to the member for raising and lowering the member and hence the roller carried thereby, control means for the motor means operative normally to raise the member to space the roller above the lower rail and operative to raise the carriage and lower the member to cause the wheels of the carriage rollingly to engage the upper track of the upper rail and the roller rollingly to engage the open interlocking seam of the sheet metal article overlying the groove in the lower rail for closing the same as the carriage is rolled along the upper rail, a pair of arms pivoted for horizontal movement to each side of the lower rail, and a guide bar carried by each pair of pivoted arms to be adjustably positioned for supporting the outer portions of the sheet metal articles received on the lower rail.

7. Apparatus for closing interlocking seams in sheet metal articles comprising, an elongated lower rail having a longitudinally extending groove on its upper surface and adapted to receive a sheet metal article having an open interlocking seam overlying the groove, an elongated upper rail parallel to and spaced from the lower '10 rail nd having spaced facing upper and lower tracks, a carriage having wheels located between the spaced facing upper and lower tracks and normally suspended by the lower track for rolling movement therealong, a member vertically movably carried by the carriage below the upper rail and having a roller carried thereby and protruding downwardly therefrom, motor means carried by the carriage and connected to the member for raising and lowering the member and hence the roller carried thereby, control means for the motor means operative normally to raise the member to space the roller above the lower rail and operative to raise the carriage and lower the member to cause the wheels of-the carriage rollingly to engage the upper track of the upper rail and the roller rollingly to engage the open interlocking seam of the sheet metal article overlying the groove in the lower rail for closing the same as the carriage is rolled along the upper rail, and a pair of clamping devices slidably carried by the lower rail, each including a member slidably engaging the lower rail, a clamping lever carried by the member and adapted to clamp the sheet metal article to the lower rail, toggle levers carried by the member for operating the clamping lever and trip means carried by the toggle levers adapted to be engaged by the carriage for releasing the clamping levers.

HARRY S. KAISER.

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

UNITED STATES PATENTS Number Name Date 558,735 Luckett Apr. 21, 1896 727,629 Hill May 12, 1903 1,521,725 Stanley Jan. 6, 1925 1,541,539 Webb June 9, 1925 1,612,519 Lindgren Dec. 28, 1926 2,497,682 Mertz Feb. 14, 1950 2,516,322 Jacokes July 25, 1950