US2487032A

US2487032A - Apparatus for making sealing devices

Info

Publication number: US2487032A
Application number: US650715A
Authority: US
Inventors: Hans F Stoffel
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-02-27
Filing date: 1946-02-27
Publication date: 1949-11-01
Anticipated expiration: 1966-11-01

Description

Nov. l, 1949 H. F. s'roFFEL APPARATUS FOR MAKING SEALING DEVICES s sheets-sheet'l Filed Feb 27, 1946 Nov. 1, 1949 H. F. sToFFEL 2,487,032

APIARATUS FOR MAKING SEALING DEVICES Filedeb. 27, 194e s sheets-sheet 2 Nov. l, 1.949 H, F. sTor-'FEL 2,487,032 l APPARATUS FOR MAKING SEALING DEVICES Filed Fei. 27, 1945 s sneaks-sheet s Patented Nov. 1, 1949 vUNITED STATES PATENT OFFICE APPARATUS FOR MAKINGSEALING DEVICES Hans F. Stoffel, Scarsdale, N. Y.

Application February 27, 1946,A Serial No. 650,715

"7 Claims. 1

articles to be sealed.

AIt is another object'of this invention toprovide means affording the continuous supply of preshaped blanks 'from one station of a machine, then working and transforming said blanks at another station to open, cap-shaped sealing devices, and closing said sealing devices at anal station (by ya curling operation) while the same are lappliedto respective articles to be sealed.

A'further object of this invention is `toprovide means enabling improved and simplified kmanufacturing steps for obtaining cap-shaped sealing devices, and further means adapted to achieve timed relationship between forming and closing actions on said sealing devices.

yStill another object `of this invention is to vprovide means permitting rapid formation of smoothly finished open 'sealing devices from a stack of sealing blanks carried by a magazine and speedy and `secure closure of such sealing devices for application Ato any desired articles tolbe prow tected'against tampering, injury, etc.

Yet, a further object of this invention resides in the provision of means eifectuating the 4curling of the rim portion of a sealing devicefor closing the same and for 'accommodatingtherein one or more portions of a cordystring or wire from an article to which said string or wire has been applied,

Still another object of this invention is to provide means contributing to eiiicient, speedy and uninterrupted operation of the forming and closing'implements employed for said'sealing devices, the partsof said Vimplements being so arranged and constructed :that they only necessitate a minimum of space although these implements comply substantially with all requirements of the practice and permit their handling even by unskilled labor.

A still further object of the zpresent invention is to provide means ensuring smooth working conditions of the synchronizedparts of the machine :made in accordance with this invention 2 by which a vsubstantially nat seal blank is subsequently suppliedto cooperating dies for forming dish-shaped sealing means devoid Yof any wrinklesor other uneven surface portions, and

lthen transferred toat least one other die by which the dish-shaped sealing means is further worked upon and closed.

These and other'objects and advantageswill y follow from the `ensuing specification and attached drawings illustrating one of many possible embodiments lof the invention.

In the drawings:

Fig. 1 is a side-elevational view of a machine (some parts being shown in section, other parts beingbroken away) for'producing sealing devices and embodying 'the invention.

Fig. 2 is a'sectional view'taken along line 2-2 of Fig. land disclosing the supply mechanism l for `seal blanks.

f-Fig. 3 is a topplan view of the supply mechanism for seal blanks and a `further Adetail for retaining each blank vin the machine.

Figs. 4 to 10 illustrate various steps (diagrammatically indicated) `of the process of shaping a seal cap from a seal blank and the transformation of the seal cap to a closed sealing device.

Fig. 11 is a fragmentary top plan view of the feeding mechanism with a preshaped seal blank inserted therein.

Fig. lZillustrates a closed sealing device with a cord -enclosedin the curled rim portion thereof, as `producedin accordance with this invention.

Referring now particularly to the attached drawings, there are more schematically disclosed in Figs. l and 2 the connections between the main parts of -a machine by which this invention may becarried into effect.

On base plate 20 of the improved seal forming and closing machine 2|, vthere is supported by means of asuitable bracket (not shown) a shaft v22 7^which is driven by a motor or similar power meansinot shown). vShaft 22 carries a cam `23 which is in engagement with oppositely disposed rollers 24 an`d125. Roller 24 is attached to a rocker l lever '26 which is `pivpted at 21 about an axle 28 extending Abetween standards 29 and 3i] which are lxed in any appropriate manner tos the machine base 20 (these standards being shown in Fig. 1 broken away).

.Roller 25 is mounted on lever 3l at 32, said lever 3l being pivotally supported on a suitable horizontal shaft33. Leverl has a fork-shaped eXtensionS forming an integral part of lever 3|.

It will be noted from Fig. .1 that rocker lever 26 and lever-3| are interconnected by means of .a

coil spring 36 which is anchored and held in position at studs 31 and 38, respectively. Further afxed at stud 31 is another coil spring 48 which extends to an operating linkage device 39 which is secured at 4| to the base 28 of the hollow base frame of the machine 2|.

Fixed adjacent lever extension of lever 3| is a cam-shaped part or lobe 42 which coacts with a roller 43 of a reciprocating lever 44 later referred to.

Lever extension 35 has two arms 35a, 35h, respectively, mounted on the ends of a cross block 45, which may be adjusted relatively to shank or rod d6 by means of two pairs of

nuts

41 and 48, engaging the threads 49 of rod 46, as is well understood.

Connected with lever extension 35 is further a pusher lever or swinging arm 58 which is attached by screw bolts 52, 53 to an angle piece 5| of lever 3|. Arm 58 carries an adjustable abutment 55 xed to said arm by means of a lock nut 54. The forward and free end 56 of pusher arm 58- is adapted to follow the reciprocating movements of rod 46 (arrow B) through the lever connection 45-35a-35b-35-5 |-58, lever 3| being actuated and controlled in its movement by the springurged engagement of roller 25 with the cam surface 23a of the revolving cam 23.

As will be apparent from Figs. 1 and 2, rocker lever 26 is operatively connected (by means of eyelets 68, 6i of yoke-shaped end piece 62 and of pin or axle 63) with the head or end piece 64 of a shank or spindle 65 which actuates the upper forming die 61 held in slidable relation to sleeveshaped holder member 66. This holder member is enabled to swing together with shank 65 and die 61 about axle 83 when arm 58 is pushed against said holder member and overcomes the action of spring 64a which extends between head piece 64 and the end o-f lever 26 which is positioned adjacent head piece 64.

In alignment with and opposite upper forming die 61 is a lower forming die 68 which is guided for reciprocating motion relatively to a platform 18 within a tubular pad or sleeve member 69. Centrally to and within said die 68 is disposed an ejector piston 1| which is supported by a coil spring 12 housed in a hollowextension of said die 68.

Fixed to base plate 28 inn any suitable manner (by welding or bolt. and nut connection) is a framework 13 which carries a fulcrum bar 14 and an anvil holding device 15 adapted for cooperation with said upper holder member 66 carrying said die 61. The position of holder member 66 (indicated by dot-dash lines and designated by II) oppositely to said anvil holding device 15 is seen in Fig. 1.

The drawings show a further position of holder member 66 (indicated by dot-dash lines and designated by I) opposite to the lower forming die 68, also illustrated in Fig. 1, whereas the position of holder member 66 (upper and lower parts thereof being broken away), its relation to arm 58 and the coordinated relationship between cam device 23 and levers 26, 3| and 35 are depicted in full lines in Fig. 1.

Cam 23 not only operates levers 26 and 3| and controls their movements, but also times the movements of supply mechanism 88, as will be hereinafter set forth.

Movement to supply mechanism 88 is imparted by rocker lever 26 and spring 48 which engages lever 8| of linkage device 39. Lever 8| is fixed to and connected through pin 82 with lever 83, said pin 82 being supported in a suitable bearing 84. Rod 85 is linked to the free end of lever 83 and is pivoted at trunnion 86h to control bar 86, whose end piece 86a is swingably supported in a suitable bearing 81 on base plate 28. The opposite end of rod 86 is ball-shaped at 88 and engages a bearing ing for fixation into a slot 96 of reciprocating slide It will be well understood that by movements of rocking lever 26 a tension of the spring 48 is caused which imparts movement to lever 8| in the direction of the arrow, thus actuating rod 85 and control bar 86 against action of spring 9|. Thus, bar 86 transmits to slide 98 a to and fro movement in accordance with arrow C. Slide 98 is provided at its forward end with a nose 91 for guiding a seal blank |88 made of any suitable, preferably metallic material and provided with curved notches 98 and 99 (Fig. 11).

Slide or pusher plate 98 is of considerable thickness, as seen in Fig. 4 and as compared with the thickness of each blank with which said pusher plate engages. Pusher plate 98 may therefore be of rigid construction and is suitably supported on a frame 98a, Fig. 2 shows a magazine |8| from which a sta-ck |82 of blanks |88 may be fed successively onto slide 98. As can be further realized from Fig. 2, magazine |8| consists of two upwardly extending round standards |8|a, 8|b between which the stack |82 of blanks |88 is positioned with

notches

As seen in Fig. 4 on an enlarged scale, the lowermost blank |88 furnished through opening |84 of table 18 from magazine |8| is moved laterally in the direction of arrow D toward a cylindrical opening |85 where said blank or disk is clamped against the undersurface of 18 at 18a and 18h by guide member 69 (Figs. 4 and 5).

By means of the power-driven, in the direction A revolving cam 2 3, lever 3| and through it lever 35 are caused to rst move downwardly lower die 6B together with piston 1| (Fig. 4) to a position indicated in Fig. 5. Lower die 68 is provided with an upper beaded edge 68a, as depicted in Figs. 5 to 10.

Figs. 6 and '7 illustrate how the lower die 68 together with piston 1| is then gradually moved upwardly (by the aforesaid cam mechanism) thereby permitting those blank portions of blank |88 positioned at 18a and 18b to slip out between the underface of table 18 and upper edge of sleeve member 69, the latter being surrounded by spring 69a which urges said member 69 downwardly and away from table 18. Thus, a cap-shaped sealing device |88a is formed without any wrinkles and which is subsequently guided through opening |85 of table 18 against the upper die 61. Upper die 61 is provided with a, recessed, ring-shaped formation 61a which is adapted during reciprocal movement to cooperate with the beaded edge 68a of the lower die so as to shape said blank and to prepare it for the cup formation. Holder 66 consequently retains by means of the springy fingers |86 and |81 said cup-shaped device 10011, said fngers releasably gripping rim |001; within the notches 98, .99.

In order to :further positively guide rim |.00b during the .ensuing 'upward .movement of said device |00a, spring-.actuated stripper members |08, A|109 are arranged on platform 10, which are pivotedzat ||0 and respectively. Ends ||2, l'lsnare lurged apart by fmeans fof a spring member ||4 (Fig. .3), vwhich is housed in part ||4a fixed to platform by ra suitable screw bolt Hlb. Thus, `during upward 'movement of lower die 68 with piston 1|, the forward ends of the stripper `members |08, v|00 zwill `be urged outwardly lin ithe direction v'of arrows E `to permit passage of rim 1001i past the curved stripper 'members |08, |100 against fthe action of said spring |14.

Therbottom-edgesfofsaid stripper members 108, I|09 Awhich face platform *mare preferably somew'hatfcurve'd so as'to Afurther-ensure smoothguiding of the cup-shaped sealing device or element |0|Ja linitsfu'ptlnust through opening "|05 of platvri'orm 10 onto the upper die member 61 within holder "A56 *(Fig. 9).

IAs 'can be seen in (Fig. '10, during the upward movement of "die member 61 the cap-shaped 'sealing device gripped 'at its

notches

98, 99 by said springy fingers |05, |01 isthus transferred vto and rmly located on holder 66, while piston 1| due y'to the 'action of Asprung: 12 still supports and bears againstthe `median portion ||5 of cup element |00a until lower 'die 60 is vsuiiiciently retracted Ain the direction of arrow F (by'means of'theabove mentioned cam driving mechanism) relatively to's'aid sleeve or guide member 69 and opening |05 in platform10, as it is clearly indicated by the downwardly moving steps of -die 'member "58 with piston 1| .in Figs. 4 and .5.

During the downward movement of .lower die member 68 the feeding mechanism 80, as .hereinabove described, vis set .into action to feed the lowermostsealing blank from :magazine `|0| below opening or passageway |05 of platform 10 (Fig. 5). Subsequently sleeve 4or guide member $9 is forcedagainst said blank vto clamp the same :in-desired position during the engagement of cam or lobe 42 with roller 43. This engagement is caused -by an upward movement of rocking lever dtaboutipivot 14a. offulcrum 14 which in turn is yieldingly supported at 14h on bolt 13a. Bolt 13a Iis fixed to frame 13 (Fig. 1).

Further, during the aforesaiddownward movement of lower diemember "68, control arm '.50 Iis forcedrfrom one extreme .position (shown in dotd'ash lines and 'indicated vvby la) Lto abut with its free end 55 againstholder 66 and `to swing the same about pin 63 (against action of spring 64a) to another-extreme position (shown in dot-dash lines and indicated by IIa) in whichholder 66 comes to lie opposite said anvil carrying device 15 (Figs. A1,4 and 5').

As 'soon as this position (indicated by II in Fig. `1) Vof holder 66 is reached, rocker 'lever 26 is actuated by the engagement of cam v23 with roller 24 and imparts to spindle 65 a downward sliding movement within and relative to holder member 66 (against action of a spring 56a), 'which is Vstill engaged by the end 56 of arm '50. This downward movement of spindle 05 to which saidupper die l61 is connected, effectuates a bearing of the aforesaid median portion |.|.5 of sealing cap device |0`0a against .the upper face [I6 of an anvil ||1 which is supported by a coil 'spring .HB Vwithin a housing H9 of said anvil holding device 15.

AThe penetration of punch member 61 `into bore |2| causes anvil ||1 to recede (in the direction of arrow G) within said housing ||9 while said anvil v| |1 is guided within a narrower Abore |2|a provided in portion |20 of holder Adevice 15.

The space |25 between the lug-shaped wall portions |23, |24 is used to facilitate insertion of a cord or string-like element |26 before punch member `6'1 with cap-shaped element |00a, comes into engagement with anvil ||1. This cord in contact with the rounded die or curling edge y|22 is then enclosed'duringthe ensuing curling operation of rim portion, |002) of element |00a, within the inwardly curled rim |0073, as can -be more clearly seen in Figs. 5 and ll2. `When holder 66 is moved in thedirection of anvil holding ymember the forward edge 66b-of holder 66 will `come into abutting relation with upper face |21 of portion of holder device 15 and is retained thereon in position against -the action of spring 66a which abuts `against holder part 65a, surrounding spindle 6'5.

It can thus be seen that the extent of curling ofthe end of rim |001) of cap-shaped element 00a, at rounded edge |22 can kbe regulated by means of adjustable screw member |30. Such curling action is dependent on the thickness of the cord to be enclosed in the sealing device 'when transformed into closed position. It can be easily y realized "that the relative position of the upper face M6 of anvil ||1 relatively to the curling die edge |22 controls the extent of curling of rim |0511 in accordance with the thickness of employed cord |26.

In order to provide for a smooth, but effective actuation of the various machine parts and more particularly to brake somewhat the swinging movements of holder l66 with respect to swinging arnrE, a hydraulic device is disposed on base plate 20. This 'device |35 has a reservoir |36 for suitable fluid, ysuch as oil |31, which reservoir communicates lwith a substantially cylindrical housing |40 through channels |38, |39.

Cylindrical housing |40 includes an upper reduced or contracted portion Uil. The lower part of housing |053 forms a seat for a ball element |42 which is adapted to check (damming action) the passage of the oil between reservoir |36 and housing |40 through channel |38. In order to provide access to said housing and channel as well as to regulate the quantitative iiow of fluid from housing 0 through channel |30, screw bolt |43 isprovided which threadedly extends through wall opening |44 of device |35.

Into contracted housing yportion |l|| and fur-` ther into the lower portion of housing |40 is adapted to project a piston |46 whose diameter substantially corresponds to and slidingly fits the wall of the cylindrical bore forming said contracted housing portion 4|. Piston |46 is connected to rod or spindle 46 by a cylindrical stem or extension |45 whose diameter is somewhat reduced with respect to that of piston |46 so that extension |45 permits in the bore of contracted housing portion |4| for the passage of fluid |31 through channel |39 between reservoir |36 and housing portion |4|. Channel |39 is so disposed that it forms a means for levelling the uid |31 between reservoir |36 and housing |40 and past piston |46 in the position thereof when it projects into the enlarged lower part f housing |40.

Briefly, the operation of the machine hereinabove outlined is as follows:

While a seal blank is furnished from the magazine |0| onto the Aslide 90 and is then guided along slot 90b (Fig. 4) into the opening |05 of the platform '|0, a previously formed, dish-shaped sealing device |||0a has been shifted by means of the holder device 66 into aligned position with the anvil holding device 15. All these movements are initiated, followed up and repeated by the cam driving mechanism which is actuated by shaft 22 to which cam 23 is affixed. During the revolutions of cam 23 levers 3| and 26 are so moved and controlled that the supply of seal blanks, as aforesaid, the formation of the dish-shaped seal and its transfer to the anvil are so timed and effectuated, that a continuous operation of the machine is achieved.

In order to provide a braking or damming effect for the swinging die holder 6'6 relatively to the movements oi' the swinging arm 50 which is actuated from lever connection 3|-35, and in order to further cushion the movements of other machine parts, such as dies, and to bring about resiliency and smoothness during operation of the machine, the aforesaid hydraulic device |35 is alignedly disposed on the machine with spindle or rod 45.

It is well understood that regulation of the position of the set screw i 43 will cause a displacement of ball |42 and will consequently permit a change of the uid flow passing from housing |40 through channel |30 into reservoir |36, whereby a desired braking eifect of the moving parts of the machine will be attained.

It is to be noted that withdrawal of the curled and closed cap element |00a from holding device 'I5 is brought about by spring H0 urging upper part of anvil H7, which works as an ejector, out of the enlarged portion |20, whereby element |00a still in contact with face IB of anvil I1 is ejected from Within the hollow of said enlarged portion |20. During this ejection operation die 61 is then moved by shank 65 and rocker lever 26 through the aforesaid cam action from position II to position I again in alignment with lower die 68.

It can thus be seen that in accordance with this invention there have been provided a method and means for manufacturing from a stack of flat, preshaped seal blanks, dishor cap-shaped sealing devices which are subsequently transferred and subjected to means for curling and closing said sealing devices.

Having thus described what is claimed as new and desired to be secured by Letters Patent is:

1. In a machine of the character described, the combination of a platform having an opening, supply means for successively delivering substantially fiat metallic blanks to said opening, a pair of reciprocable dies disposed for position, respectively, at either end of said opening and shaped to transform each supplied blank in cooperation with said opening to a substantially dish-shaped sealing device, retaining means projecting from one of said dies, means to move the other die through said opening to shape and to transfer said dish-shaped sealing device to said retaining means, a further die positioned adjacent said reciprocable dies, pusher means for moving said one ydie with said dish-shaped sealing device retained thereby to said further die for coaction therewith, said further die being provided with a rounded edge for curling and closing said sealing device, said supply means and said reciprocable dies being movable relatively to each other, and power driven cam-lever means operatively connected, respectively, to said pusher means, to said supply means and said reciprocable dies for imparting movements to the same in timed relation.

2. In a machine of the character described, the combination of a platform having an opening,

` supply means for successively delivering substantially flat metallic blanks to said opening, a pair of reciprocable dies movable for position, respectively, above and below said opening and shaped to transform each supplied blank in cooperation with said opening to a substantially dish-shaped sealing device, retaining means associated with one of said dies, means to move the other die through said opening to shape and to transfer said dish-shaped sealing device to said retaining means, a further die positioned adjacent said reciprocable dies, pusher means for moving said one die with said dish-shaped sealing device retained thereby to said further die for coaction therewith, said further die being provided with a rounded edge f-or curling and closing said sealing device, said supply means and said recip'rocable dies being movable relatively to each other, and power driven means operatively connected, respectively, tosaid pusher means, to said supply means and said reciprocable dies for imparting movements to the same in timed relation.

3. In a machine of the character described, a magazine for holding metallic flat blanks, slidalble supply means positioned at one end of said magazine, a platform having an opening, said supply means being arranged to successively deliver said blanks from said magazine and to said opening, a pair of reciprocable dies disposed for position, respectively, above and below said opening and shaped to transform each supplied blank in cooperation with said opening to a substantially dish-shaped sealing device, retaining means associated with one of said dies, means to move the other die through said opening to shape and to thereby transfer said dish-shaped sealing device to said retaining means, a further die positioned adjacent said reciprocable dies, said one die being arranged for pivotal movement, pusher means to swing said one die with said dish-shaped sealing device retained thereby to said further die for coaction therewith, said further die including a rounded edge for curling and closing said sealing device, said supply means and said reciprocable dies being movable relatively to each other, and power driven means operatively connected, respectively, to said pusher means, to said supply means and said reciprocable dies for imparting movements to the same in timed relation.

4. A machine for manufacturing sealing devices and applying the latter to string means connected to articles to be sealed comprising a magazine for holding a stack of flat seal blanks, a platform having an opening, slide means supplying successively seal blanks from said magazine stack to said platform opening, a pair o-f reciprocable dies positioned for cooperation with one another, respectively, above and below said platform opening, one of said dies being provided with a beaded edge, the other of said dies being provided with a ring-shaped recess corresponding to and cooperable with said beaded edge, said reciprocable dies in cooperation with said opening being adapted to shape each blank into a cup-shaped sealing device with a downwardly directed rim, means on said other die for retaining said cup-shaped sealing device thereon, a further die positioned adjacent said reciprocable dies, and means for transferring said other die with said cup-shaped sealing device to said further die, said further die coacting with said other die for curling said rim and enclosing said string means in said curled rim.

5. A machine for manufacturing sealing devices and applying the latter t string means connected to articles to be sealed comprising a magazine for holding a stack of fiat seal blanks, a platform having an opening, means supplying successively said seal blanks from said magazine to said platform opening, a pair of cooperable dies, upper and lower dies, respectively, positioned above and below said platform opening, said dies being respectively formed so as to transform each seal blank supplied to said opening in cooperation with the latter to a cup-shaped sealing device with a downwardly extending rim, v

anvil means positioned adjacent to and coacting with one of said dies, means carried by one die for retaining said cup-shaped sealing device thereon, means for transferring said one die with said cup-shaped sealing device to said anvil means, -said anvil means being provided with a rounded edge and being cooperable with said one die for curling said rim to close said sealing device and to incorporate in said closed rim said string means upon action of said one die with said anvil means, and a power driven mechanism operatively connected to said supply means and said pair of dies to move the same in timed relation.

6. A machine for manufacturing sealing devices comprising a magazine for holding a stack of fiat seal blanks, a platform having an opening, a slide plate arranged for movement between said magazine and said platform therebelow, the thickness of said slide plate being greater than that of each blank, said slide plate being adapted to successively supply seal blanks from said magazine stack to said platform opening, a pair of reciprocable dies positioned for cooperation with one another, respectively, above and belowsaid platform opening, said reciprocable dies being shaped to transform in cooperation with said opening each supplied blank to a substantially cup-shaped sealing device with a downwardly directed rim, one of said dies being provided with retaining means for engagement with said cup-shaped sealing device, further die means positioned adjacent said reciprocable dies, one of said dies being disposed for movement and cooperation with said further die means for curling the rim and closing the respective sealing device, and means for transferring said one die with said cup-shaped sealing' device to said further die means.

7. A machine for manufacturing sealing devices comprising a, magazine for holding a stack of at seal blanks, a platform having an opening, a slide plate arranged for movement between said magazine and said platform therebelow, the thickness of said slide plate being greater than that of each blank, said slide plate being movable for successively supplying seal blanks from said magazine stack to said platform opening, a pair of reciprocable dies positioned for cooperationwith one another, respectively, above and below said platform opening, said reciprocable dies being shaped to transform each supplied blank in cooperation with said opening to a substantially cup-shaped sealing device with a downwardly directed rim, means on one of said dies for retaining said cup-shaped sealing device thereon, die means positioned adjacent said reciprocable dies, said one die being disposed for movement and cooperation with said adjacent die means for curling the rim and closing the respective sealing device, pusher means for moving said one die together with said cup-shaped sealing device to said die means, and power driven cam-lever means operatively connected, to said pusher means, said slide plate and said reciprocable dies, respectively for imparting movements to the same in timed relation.

HANS F. STOFFEL.

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

UNITED STATES PATENTS Number Name Date 1,354,785 Strand Oct. 5, 1920 1,575,300 Weeks Mar. 2, 1926 1,772,820 Troyer Aug, 12, 1930 1,772,914 Rode Aug. 12, 1930 1,848,383 Rode Mar. 8, 1932 1,849,691 Rode Mar. 15, 1932 1,940,581 Carter Dec. 19, 1933 2,209,416 Montelione July 30, 1940 2,282,197 Gibbs May 12, 1942 2,303,539 Gibbs Dec. 1, 1942 2,346,197 Stelzer Apr. 11, 1944 2,371,414 Stelzer Mar. 13, 1945