US2567649A

US2567649A - Hydraulic die-casting machine

Info

Publication number: US2567649A
Application number: US753190A
Authority: US
Inventors: Louis H Morin
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-06-07
Filing date: 1947-06-07
Publication date: 1951-09-11
Anticipated expiration: 1968-09-11

Description

Sept. l1, 1951 L. H. MORIN HYDRAULIC DIE-CASTING MACHINE Filed June '7. i947 4 Sheets-Sheet l Sept. 11, 1951 L.. H. MORIN HYDRAULIC DIEj-CASTII\IGl MACHINE 4 Sheets-Sheet 2 Filed June '7. 1947 INVENTOR l @w MOR/N BY r ATTO R N EY 4 Sheets-Sheet 3 Sept. l1, 1951 H. MORIN HYnRAuL-Ic DIE-CASTING MACHINE Filed June 7. 1947 -flw Sept. l1, 1951 L. H. MORIN HYDRAuLIcnIE-CASTING MACHiNE 4 Sheets-Sheet 4 Filed June '7. 1947 S@ ha aff@ Patented Sept. 11, 1951 UNITED STATES PATENT oFElcE HYDRAULIC DIE-CASTING MACHINE Louis H. Morin, Bronx, N. Y.

Application June 7, 1947, Serial No. 753,190

6 Claims.

This invention relates to die casting machines of the automatically actuating type and, wherein, a casting is formed on a core or carrier pin and, then, moved to a trimming station and that part of the casting remaining on the core or carrier pin is, then, moved to a stripper station. More particularly, the invention deals with machines of this, kind wherein the dies are hydraulically moved into closed position or abutting engagement and, wherein, the stripper mechanism and other mechanisms of the machine are pneumatically operated. Still more particularly, the invention comprises a machine, wherein the hydraulic unit is mounted for quick attachment and detachment to give access to the die holders and dies facilitating quick attachment and removal of the dies and die holders.

This application is a continuation-in-part of my copending application Ser. No. 574,697, filed January 26, 1945, entitled Coreless Scoop Machine, now matured into Patent No. 2,497,010.

Certain features of the machine described but not claimed herein are described and claimed in applicants copending applications as follows: application Serial No. 753,673, filed June 10, 1947; application Serial No. 753,674, filed June 10, 1947, now matured into Patent No. 2,533,035; application Serial No. 758,867, led July 3, 1947, now matured into Patent No. 2,542,556; and application Serial No. 758,868, led July 3, 1947, now matured into Patent No. 2,543,417.

The novel features of the invention will be best understood from the following description, when taken together with the accompanying drawings, in which certain embodiments of the invention are disclosed and, in which, the separate parts are designated by suitable reference characters in each of the views and, in which:

Fig. 1 is a front view of the upper portion of the machine made according to my invention with parts of the construction broken away and in section and diagrammatically illustrating the electric circuit.

Fig. 2 is a section substantially on the line 2--2 of Fig. 1 showing parts of the construction broken away.

Fig. 3 is an enlarged, vertical, sectional View with one of the die guides and associated mechanism and through the workpiece shifting and stripper machanism.

Fig. 4 is a section substantially on the line 4--4 of Fig. 3.

Fig. 5 is a section on the line 5-5 of Fig. 3.

Fig. 6 is a section on the line 6-6 of Fig. 3; and

Fig. 7 is a diagrammatic view showing the hydraulic, pneumatic and electric system of the machine.

In Fig. 1 of the drawing, I have shown, at I0, the 4upper portion of the base of a machine, upon which is supported a main frame, generally identified at Il and, in this frame, is suitably supported a main drive shaft I2 suitably driven from an electric motor and diagrammatically illustrated at I3 in Fig. l and Fig. 7 of the drawing. At this time, it is pointed out that all of the detail mechanisms of the machine are not shown in order to simplify the present invention. On the frame II are upwardly extending similar side plate portions I4, I4' joined at the top in a crosshead I5 and these portions have pairs of outwardly extending upper and lower arms I6, I6', as shown at the right of Fig. 1, a similar pair being on the plate side I4. Rearwardly of the plates I4, I 4' are smaller plates I'I, I1' suitably secured in the frame and these plates have outwardly extending pairs of upper and lower arms at each side thereof, asseen at I8, I8 at the left of Fig. 1 on the plate `I'I and a corresponding pair being at the right side of Fig. 1. In Fig. 5 of the drawing, a section is shown through both pairs of arms I6, IG'; I8, I8.

Arranged between the plates`l4, I4'; I1, I1' at each side of the machine are upper and lower blocks I9, I9', note in this connection Fig. 2 of the drawing, showing the blocks at the left of Fig. 1. The blocks to the right are shown in longitudinal section in Fig. 3 and part of the blocks to the left are also indicated in said gure. Inner surfaces of the blocks I9, I9 have facing or liner plates 20, 2I and corresponding surfaces of the plates I4', I 'I' have facing

plates

22 and 23. These plates are indicated, for the most part, in cross-section in Fig. 2 of the drawing and form therebetween a slideways 24, 24', note Fig. 3, in which two die supporting

members

25, 25 are mounted. This construction will be clearly understood from a consideration of Figs. 2 and 3 of the drawing, also taking into consideration Fig. 4. In order to provide a close tting and proper alined guide for the die supporting members 25, 25', means is provided for movingr the plates 2I and '22 inwardly. Considering Figs. 2 and 3, it will appear that a series of.-A pressure pins 26, having lower conical ends, las

3 ends 26', as will appear in Fig. 2. The plates 22 are adjusted inwardly by screws 28, as seen. for example, in Fig. 4 of the drawing. Hinged to the free plates I4, I4', as at 29, are cover plates30, 30' supporting, on their inner sur- 5 faces, pressure and guide plates 3l. one of which is shown in Fig. 4 of the drawing. These cover plates operate in cutout portions 32 in the plates I4, I4' and are adapted to provide means for detaching the dies 33, 33' from the

supports

25, 25 through the medium of L-shaped brackets, one of which is shown in section at 34 in Fig. 4 of the drawing. The brackets 34 are countersunk in the die supports 25, 25' and secured thereto by screws 35 and also keyed in position by key pins 36. Upon removing the screws 35, the brackets 34 can be detached, with the cover plates swung into raised position, and the dies can be detached from the brackets by removing screws, one of which is indicated in dotted lines at 31 in Fig. 4 of the drawing. With this construction, it will be apparent that dies may be removed for repair or their replacement of dies Without removing the holders or die supports or disturbing their alignment in the machine.

In the present construction, only one half of the machine is shown in detail and. from this standpoint, it will be understood that both sides of the machine with respect to the die holder and operating mechanism are the same and the brief description of one will apply to the other.

Secured to the outer end of each die support is a T-shaped block or cross-head 38, with which is coupled two rods 39, 39', note Fig. 4, the coupling being made through the medium of a pin 40 passing through the block 38 and the inner apertured ends 4|, 4| of the rods. The rods extend outwardly threaded sleeves 42, 42' adjustably supported in split bearings 43. 43 on the sides of a cylinder 44. On the outer ends of the rods are adjustable collars 45, 45', against which one end of springs 46, 46' operate, the other ends of the springs seating in the

sleeve

42, 42. In this manner, the tension of the springs may be adjusted. For additional details of this arrangement providing for the spring-return of the hydraulically operated dies 33, 33' and the die supporting

members

25, 25 reference may be made to my copending application Serial No. 753,673, filed June 10, 1947, referred to previously herein.

The die supporting members 25, 25' may be moved to bring the

dies

33 and 33 into closed position and to hold the dies in that position in any suitable manner. In the illustrated embodiment of the invention the actuating means for the die supporting members 25 and 25' are hydraulically operated.

Mounted in the cylinder 44 is a suitable piston or plunger `41 which extends through a packing or gland 48 in the inner open end of the cylinder, the piston or plunger bearing upon the surface of the block 38. At the outer end of the cylinder 44 is a cap 49 having a central bore 50, with which communicates a pipe for supplying oil under pressure to the cylinder in advancing the piston or plunger inwardly to move the dies into closed position. The'pipes 5|, as well as the cylinders 44, pistons 41 and die supporting members 25, 25' are shown diagrammatically in Fig. 7 ofthe drawing. Both pipes 5| lead to a suitably actuated control valve 52 diagrammatically shown in Fig. 7 and is shown in section in Fig. 2, which controls the supply 'and discharge of oil to the respective cylinders.

The valve element 53 of the valve devices 52 is actuated through a cam 54, later described and, in the position shown in Fig. 2, the valve element shows the valve in position placing the pipe 55 extending from the pump 56, note Fig. 7, in communication with the two pipes 5|, for supply of oil to the cylinders. Extending from the valve device is a return pipe 51 for allowing the oil to drain lback into the tank orreservoir 58.

The cylinder 44 includes a pair of inwardly extending bearing

portions

59, 59 arranged between the arms |6,.I8, I6',l I8', as clearly seen in Fig. 5 of the drawing. Passing through said bearings and arms are quickly removable pins 60, 60' having kouter knurled heads 6|, 6|' and reduced collar portions 62, 62'. Fitting in the collar portionsare hook-shaped retaining members 63,'63 which may be quickly swung into position, freeing the pins, thus allowing said pins to be withdrawn after inner

key pins

64, 64 have been removed. In this way, the hydraulic umts may be quickly detached from the machineand the die supports 25, 25 with the dies thereon can be readily removed through the sides of the machine.

Considering Figs. 1 and 3 of the drawing, I have shown means controlling operation of the machine so that, if the dies fail to be moved into a fully closed position, the machine will be automatically stopped and the gooseneck, including the molten metal discharge, will be checked to avoid functioning of these mechanisms when the dies are not in position to receive the molten metal discharge. The outer end portions of each die supporting member has an upwardly extending bracket 65, in which is adjustably supported a, control screw 66 operating upon a plunger pin 61 in an air cylinder 68. The p in 61 is normally supported in engagement with the screw 66 by a spring 69. Extending into the cylinder is an air line 10 from a suitable air compressor, not shown. Extending from the cylinder is an air discharge pipe 1| and the pipe of one cylinder communi- Cates with the other, as seen at 1| in Fig. 7, to extend to a diaphragm switch operating element 12 and to a gooseneck control cylinder 13, the latter being shown in detail in Fig. 2 of the drawing. In other words, the air cylinder 68 is arranged on each of the die supporting members 25, 25', as will clearly appear in Fig. 1 of the drawing and is also diagrammatically illustrated in Fig. 7. It will thus be apparent that, if the dies 33, 33 are not each moved to their fullest extent of closed position, then the die which does not so move, for any reason, will result in leaving the plunger pin 61 in an open position atthe cycle ,of operation when air is supplied under pressure to the pipe line 10, allowing the4 air to by-pass through the cylinder, the pipe 1| and, thus, to operate the diaphragm control 12 and the gooseneck control cylinder 13. Operation of the diaphragm control device 12 will break the circuit through a control switch 14 in Fig. 7 of the drawing shutting off the current supply to the motor I3. The charge of air in the pipe 1|, extending to the pipe 13, will cause the plunger 15 of the device to be moved into and held in raised position extending the protruding end 16 of the plunger to a position supporting the lever 11 in an inoperative position, that is to say, the roller 18 of the lever is held out of. engagement with its operating cam 19; thus the 'gooseneck will be supported out of engagement with the dies as more clearly hereinafter described. This construction is also diagrammatically shown in Fig. 7 and in said figure is diagrammatically i1- lustrated an electric control valve 8|, which extends to the cylinder 83 of the gooseneck 80 to control the discharge of molten metal therefrom.

The safety stop mechanism and the throwout for the Igooseneck, which have just been described, are described and claimed in my copending'applications Serial Nos. 753,674, filed June 10, 1947, and 758,868, led July 3, 1947, respectively, to which reference haspreviously been made herein.

The various controls and timing of the controls for the air lines of the machine are generally identied through a cam shaft mechanism 84, shown at the right of Fig. 1 of the drawing, the cani shaft being actuated through a bevel gear 85 suitably driven from the drive shaft of the machine. These mechanisms are not shown in detail, as they form no particular part of the present invention. Reference here is had to the supply of air in proper timing to the

supply lines

10 and 82, as well as to an air line 86, which controls operation of a stripper mechanism shown in sectional detail in Fig. 3 of the drawing and later described.

Adjustably supported on each

die supporting member

25, 25 is a stop screw 81, as clearly seen in Fig. 3, which forms a positive check, limiting closing movement of the dies.

Considering Fig. 2 of the drawing, it will appear that on the left-side of the machine is suitably supported a shaft 88 driven from the drive shaft |2 through

gears

89, 90 and 9| and adjustably supported on the gear 9| is the cam 54. The adjustment is provided to control the exact timing of operation of the plunger valve 53 and in control of the supply of the hydraulic medium to the cylinders 66. The valve 53 carries, at its outer end, a roller 92 operating upon the cam 54 and held in engagement therewith by a spring 93. In the position shown in Fig. 2, the oil under pressure is being supplied to the cylinder 44 or, in other Words, the dies are being held in closed position.

The gooseneck 80 is pivotally supported in the upper part of the frame on the adjustable side pivots 94 clearly seen in Fig. 1 of the drawing,

so as to swing the nozzle 95 toward and from the dies, the gooseneck operating in the pot or molten metal container 96, as in other devices of this kind. The lever 11 is pivoted in the top of the frame, as seen at 91, note Fig. 2, and on the pivot of the lever. is a short arm 98 carrying a roller 99, operating upon a screw |00 adjustably supported in the gooseneck. It will thus be seen that, as the arm 11 is swung upwardly or held upwardly, the gooseneck is swung inwardly on its pivots 94 to move the nozzle 95 inwardly, outof-engagernent with the dies. In Fig. 2, the nozzle is shown abutting the dies and registering with the gate passage |0|, this being als-o clearly shown in Fig. 6 of the drawing; thus molten metal or other metal may be injected into the cavity or impression |02 of the dies in forming a casting |03 on a core pin |04 supported between the dies and extending into the cavity |02. The roller 18 of the lever 11 is held in constant engagement with the cam 19 by action of a spring |05 supported on a pin |06 having a hook engagement, as seen at |01, with a part of the frame. In other words, the spring |05 urges the nozzle 95 normally in engagement with the dies and the cam 19 moves the nozzle into inoperative position against the action of said spring |05.

Supported on the frame in suitable bearings |08 are two shafts |09 and H0. Adjacent ends of these shafts extend into a housing I||, note Fig. 3, the shaft |09 being keyed to the housing, as seen at l2, so as to rotate said housing, whereas the shaft ||0 is fixed in the housing and rotates therewith. It will be seen that the shaft |I0 has an opening H3, through which the fiex ible air tube 86 passes. The tube has a suitable coupling with a capped cylinder H4, in which is arranged a plunger |I5. Fixed in the housing is a sleeve I6 which carries, at its upper end, means ||1 for adjustably clamping the core pin |04 therein to properly position the pin within the die cavity, as will be apparent. Slidably mounted in the sleeve |6 is a plunger rod I8 carrying, at its outer end, a fork-shaped stripper nger ||9 movable longitudinally of the core pin |04 to strip the remaining part of a'casting from the pin at the position indicated at ||9 in dot and dash lines in Fig. 6. The pin ||8 has a head |20 within the plunger I I5, upon which seats a spring |2| which normally holds the rod and the plunger in the downward position shown in Fig. 3. As and when air under pressure is timely introduced into the cylinder ||4, the plunger will be moved upwardly, correspondingly moving the rod ||8 and the finger ||9 in stripping the casting part from the pin |04, as will be apparent.

At the outer end of the shaft |09 is adjustably clamped a gear segment |22, note Fig. 2. Supported below the segment |22 and rotatable upon a stub shaft |23 is a gear segment arm |24 operatively engaging segment |22 in contributing intermittent rotary movement to the shaft |09 and the housing to first move a complete casting |03 to the dot and dash position as shown at |03 in Fig. 6 of the drawing, where two trimming tools diagrammatically seen at |25 and |26 -trim the casting. The tool |25 removes the gate portion |21 from the casting; whereas the tool |26 frees the casting from the part |28 still remaining on the pin |04 and it is this part |28 which is stripped from the pin at the station H9. My present invention is not concerned with the operation of the trimming tools, as this trimming operation is old in the art and it is here only diagrammatically illustrated in order to complete the description of the cycle of operation.

The frame |36 carries, at its free end, a roller |38 operating upon the cam |31 and this cam controls movement of the workpiece delivery to the trimming station and, then, to the stripper station and back to position between the dies. Pivoted to the frame |36 is a rod |39 which passes through a guide bracket |40 on the frame and a spring |4| on'the rod serves to support the roller |38 in constant engagement with the cam, while at the same time, provides a free and independent movement of the frame |36 in the event that anything should interfere with or block the swinging movement of the feed and stripper mechanism, particularly in moving the mechanism to move the pin |04 from position between the dies to the trimming station. It will also be understood that the spring |3| operates in the same manner in movement of the core pin |04 from the trimming station to the stripper station and back to position between the dies. The double throw safety mechanism for the transfer apparatus described above is also described and claimed in my copending application Serial No. '158.867, led July 3, 1947, referred to previously herein.

In Fig. 2 of the drawing, I have shown at |42 a hand lever pivoted in the frame, as seen at |43, and having at its pivot end a pin |44 adapted to engage a lug |45 on the pot 96' to manually move the pot or the nozzle 95 out of engagement with the dies. l

rI'his operation of the machine will be readily understood from the foregoing description and the following description. The dies are shown in closed position in the several views and the several mechanisms of the machine are consistent with the showing of the dies. It is to be assumed that casting material has been injected into the cavity |02 to form the casting |03, whereupon the gooseneck is actuated to move the nozzle 95 out of engagement with the dies. The dies are now moved into open position, this being accomvplished by movement of the valve 53 in position to drain the oil from the cylinders 44 and permitting the

springs

46, 46 to separate the dies. Upon separation of the dies, the housing is swung to bring the casting into the position shown at |03', Fig. 6, at the trimming station. This operation is accomplished by action of the cam |31 upon the roller |38, which swings the gear segment arm |24 to rotate the gear segment |22. After the casting has been trimmed, the cam |31 controls movement of the housing to bring the pin |04 to the stripper station, at which time, the air is introduced into the cylinder I4 to actuate the stripper nger H0; whereupon the housing is then returned to the position arranging the pin |04 between adjacent surfaces of the dies. At this time, the dies are then again closed by movement of the valve 53 back to the position shown in Fig. 2, allowing the oil under pressure to enter the cylinders 44.

The above operation is clearly understood from the diagrammatic showing in Fig. 'I and, considering this gure and Fig. 3, it will4 be apparent that the pin B1 will block the air of the pipes 10 from entering the pipes 1|, if the dies are fully and completely closed. Should either die not complete its cycle of operation, then air will be permitted to pass into the pipe or tube 1| to actuate the diaphragm 12 and the micro or other switch `|4 to immediately stop the motor I3 and to close the valve 8|, preventing air from being supplied to the cylinder 83 of the gooseneck. The other controls of the machine operation have been clearly expressed heretofore.

Considering Fig. 1 of the drawing, it will appear that the tubular end portions of the housing receiving the shafts |09, are split and adapted to be clamped together by bolts, as seen at |46, in said figure.

sure insures positive engagement of the dies with eaLh other. Such an arrangement considerably simplifies the mechanism for opening and closing the dies asv the necessity for hydraulic connections or the like to the opposite side of the pistons 41 is eliminated.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a die casting machine. having a frame and guides on said frame slidably supporting a pair of die holders in opposing relation thereon,

the combination which includes a pair of fluidpressure cylinders, means for detachably securing the cylinders to the frame of the machine in opposing relation to each other at the outer ends of the guides, each of said cylinders having a piston therein movable in a direction toward the opposing cylinder upon the admission of a fluid under pressure to said cylinders, a detachable coupling holding each ofv the pistons in engagement with the outer ends'of the respective die holders, said couplings including connecting pins extending transversely of the direction in which `the die holders move, said connecting pins being removable by a lengthwise movement thereof for detaching the die holders from engagement with It willbe understood that the springs 46 automatically operate to move the die supporting members 25, 25 outwardly, as and when the pressure on the oil or hydraulic means is released, and said die supporting members are, in other words, moved into closed position against the action of said springs; thus the springs cushion this movement while the hydraulic presthe pistons, return springs connected to the die holders and urging the die holders away from each other, said springs being connected to the die holders through the removable connecting pins of the detachable coupling and dies removably secured to the die holders at the opposing ends thereof, said dies and their respective holders being movable into and held in closed position upon admission of iiuid under pressure to the cylinders.

2. In a die casting machine having a frame and guides on said frame slidably supporting a pair of die holders in opposing relation thereon, the combination which includes a pair of fluid pressure cylinders, means for detachably securing the cylinders to the frame of the machine in opposing relation to each other at the outer ends of the guides, each of said cylinders having a piston therein movable in a direction toward the opposing cylinder upon the admission of a fluid under pressure to said cylinders, a detachable coupling holding each of the pistons in engagement with the outer ends of the respective die holders, said couplings including connecting pins extending transversely of the line of action of the pistons and being removable by a lengthwise movement of the pins, dies removably secured to the die holders at the Opposing ends thereof and adjustable bearing plates in the guides for supporting the die holders therein, said bearing plates being adjustable vertically with respect to the guides for alignment of the opposing faces of the dies on the respective die holders.

3. In a die casting machine having a frame and guides on said frame slidably supporting a pair of die holders in opposing relation thereon, the combination as defined iny claim 2 which incliides a removable cover plate secured to each of the guides and extending over the die holders supported therein, each of said cover plates including a hinged portion, said hinged portions being located at the point where the dies are attached to the die holders when the dies are Open.

4. In a die casting machine having a frame, guides on said frame and die holders having dies on their inner ends slidably supported in said guides with the dies supported thereon in o pposing relation, the combination which includes a pair of uid pressure cylinders, detachable connections securing the cylinders to the frame of the machine in opposing relation thereon to each other, said connections including removable connecting pins extending at right angles to the line of action of the cylinder, each of said cylinders having a piston therein movable in a direction toward the opposing cylinder upon the admission of a fluid under pressure thereto, detachable couplings holding each of the pistons in engagement with outer ends of the respective die holders, said couplings including removable connecting pins extending at right angles to the line of laction of the piston and `spring means connected to the die holders and tending to move the die holders away from each other, said spring means including compression springs having one end thereof heldin a xed position and the other ends thereof connected to the die holders through the connecting pins of the detachable couplings.

5. A die casting machine which includes a frame, a pair of guides supported on the frame, a pair of die holders slidably supported in said guides With their inner ends in opposing relation, said die holders being removable from the guides, a pair of hydraulic cylinders, connecting pins detachably securing the cylinders to the frame in opposing relation to each other at the outer ends of said guides, said connecting pins extending at right angles to the line of action of the cylinders, pistons in said cylinders, a detachable coupling holding each of the pistons in engagement with the outer ends of the respective die holders, said couplings including connecting pins engaging with the die holders and extending at right angles to the line of action of the pistons, dies removably secured to the inner ends of the die holders, adjustable bearing plates in the guides for supporting the die holders therein, said bearing plates being movable vertically with respect to the guides for aligning the respective die holders and the dies and a cover plate removably secured to each of the guides for retaining the respective die holders therein, said cover plates having hinged portions located at the point where the dies are attached to the die holders at one position thereof.

6. A die casting machine which includes a frame, a pair of guides supported on the frame, alpair of die holders slidably supported in said guides with their inner ends in opposing relation, said die holders being removable from the guides.

a pair of hydraulic cylinders for moving the die 10 holders toward each other upon admission of hydraulic pressure to the cylinders, connecting pins detachably securing the cylinders to the frame in opposing relation to each other at the outer ends of said guides, said connecting pins extending at right angles to the line of action of the cylinders, pistons in said cylinders, a detachable coupling connecting each of the cylinders to the respective die holders, said coupling including a removable connecting pin extending at right angles to the line of action of the pistons, spring means holding the pistons in engagement with the outer ends of the respective die holders and acting to move the die holders away from each other upon release of hydraulic pressure from the cylinders, said spring means including compression springs having one end thereof fixed and the other end thereof connected to the die holders through the connecting pin of the detachable coupling, dies removably secured to the inner ends of the die holders, adjustable bearing plates in the guides for supporting the die holders therein, said bearing plates being movable vertically in the guides for alignment of the die holders and the dies supported thereon and a removable cover plate secured to each of the guides and extending across the respective die holders supported therein, said cover plates having hinged portions positioned to expose the point where the dies are attached to the die holders when lthe die holders are moved away from each other.

LOUIS H. MORIN.

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

UNITED STATES PATENTS Number Name Date 698,591 Veeder Apr. 29, 1902 1,240,229 Lister Sept. 18, 1917 1,662,750 Kaufmann Mar. 13, 1928 1,815,361 Morris et al July 21, 1931 1,981,380 Wagner Nov. 20, 1934 1,981,381 Wagner Nov. 20, 1934 2,088,123 Toman July 27, 1937 2,129,351 Flammang Sept. 6, 1938 2,145,956 Stern Feb. 7, 1940 2,224,977 Morin Dec. 17, 1940 2,246,414 McIntyre June 17, 1941 2,298,044 Dinzl Oct. 6, 1942 2,337,766 Newell Dec. 28, 1943 2,367,303 Morin Jan. 16, 1945