US2637394A

US2637394A - Sheet cutting machine

Info

Publication number: US2637394A
Application number: US761387A
Authority: US
Inventors: Mathias J Fey
Original assignee: NICHOLS WIRE AND STEEL Co
Current assignee: NICHOLS WIRE AND STEEL Co
Priority date: 1947-07-16
Filing date: 1947-07-16
Publication date: 1953-05-05
Anticipated expiration: 1970-05-05

Description

M.'J. Fr-:Y

SHEET CUTTING MACHINE May 5, 1953 2 SHEETS-SHEET 1 Filed July 16, 194'? May 5, 1953 M. J. FEY

SHEET CUTTING MACHINE Filed July 16, 1947 2 SHEETS--SHEET 2 l l I 55'- 3? @.5

| 0 k .5a 31; I A

l 32 Y D i 30 29 INVENTOR.

Patented May 5, 19.53

,ENT OFFICE SHEET oc'rriNG Machine Mathias J. Fey, Davenport, Iowa, assigner to Nichols Wire andl Steel Company, Davenport, Iowa, a corporation of Iowa Application July 16, 1947, Serial No. 761,337

(Cl. 16d- 49) 8 Claims.

This invention relates generally to cutting mechanisms and in particular to a method for cutting sheets of very accurate length from long strips of metal or other material.

ln the prior art, various methods and machines have been devised for cutting sheets from long strips of material. Attemptshave been made to provide automatic machines which operate rapidly and at the same time provide sheets the lengthscf which are very accurate. Machines have `been devised in which'the strip of material is continuously fed and the cutting mechanism moves with the strip so that the operation takes place without interrupting the feeding of the strip. These machines which have been commonly designated as flying shears are very complicated and accordingly are expensive in original cost and require a considerable amount of maintenance resulting in high operating costs. Machines have also been produced in which a stationary shear blade is used andthe length of the material cut oli is determined by operation of the feeding mechanism.v However, prior machines of this type have not 'been entirely satisfactory as-they do not provide the desired accuracy, a tolerance of the order of one inch being about the best obtainable.

It is, therefore,l an object of the present invention to provide an improved method for cutting sheets of very accurate length Yfrom strip material.

A further object of this' invention is to provide an improved machine for automatically feeding strip material andcutting it into sheets of very accurate length.

A still further object of l this invention is to provide a relatively simple machine for close tolerance cutting of sheets from a strip of metal provided on a roll and for automatically stacking the cut sheets.

A feature of this invention is the provision of a method for close-tolerance cutting of sheets in which the portion of a strip from which the sheet is being cut is bowed across its width and thereby made rigid so that the portion of the strip extending between two predetermined points will be of a fixed length.

A further feature of this invention is the provision of a method for cutting sheets from fiat strip material in which over-run of the strip due to themomentum of the feeding mechanism does not affect the length of the sheet which is cut ofi.

Another feature of thisiinvention is the provi.- sion of ra lmachine havingl aV feeding lmechanism for feeding a strip of material past cutting means il il and including means for disengaging the feeding mechanism before the required amount of material is red and means for positively stopping the feeding of the material when the required length has'been fed past the cutting means.

Still another feature ofjthis invention is the provision of an automatic cutting machine in which strip material is fed along rail means and is automatically cut to the desired length and in which the rail meansV are retracted after the sheet is cut so thatthe sheetsare dropped and sta-cited one on top or" the'other.

A still further feature of this invention isthe provision of .a machine for cutting sheets from fiat strip material in which the strip is fed past cutting means and the portion beyond the cutting means is stifiened so that when the end thereof engages a positive stop, the feeding of the strip past the cutting means will be stopped and any additional portionof the strip fed will accumulate between the feeding mechanism and the cutting means'so that the length of the strip out oli will not be affected thereby.

Further objects, features and advantages will be apparent from aconsideration of the following description taken in connection with the accompanying drawings in'whichr' v u Fig. i is a sidevview of the automatic cutting machine -in accordance with the invention;

Fig. 2 is atop viewof the'cutting machine of Fig. l;

Fig. 3 is a detailed View of the stop mechanism;

Fig. l illustrates the `manner in which the strip is stifiened by the cutting mechanism; and

Fig. is a cross-sectional View along the lines t-sof Fig. 2.

In accordance with the invention, a method is provided for cutting sheets of very accurate length from a strip of material which may be a roll of metal suchas aluminum. ln this method the strip is fed on rail means past cutting means and the portion fed beyond the cutting means is bowed across the width thereof to stiien this portion. "i hen the end of the strip reaches a preidetermined point the feeding mechanism isfdisengaged from its `driving means and themechanism is stopped as socnas possible. However, in orde) to handle metal strips of vconsiderable width, the feeding mechanism must he relatively heavy accordingly a definite tirncis required before the feeding mechanism will stopevenwhen using effective braking means. When the .end of the strip reaches a hired point beyond the prede-y termined point it is positivelystopped and as the portion between the cutting means and the stop is relatively rigid, additional material will not be fed past the cutting means. A space is provided between the feeding mechanism and the cutting means and the portion of the strip extending in this space is not stiffened so that any additional material fed after the strip engages the positive stop may accumulate in this space. After the movement of the strip has stopped, the cutting means are actuated causing the sheet of the desired length to be cut off. This sheet is then dropped by the rails on which it is supported and the cycle started again resulting in the cutting of additional sheets. An automatic machine for accomplishing this method has also been provided and will be described in detail hereinafter.

Referring now to Figs. 1 and 2, there is illustrated one form in which the cutting machine in accordance with the invention may be embodied. This apparatus includes a feeding mechanism generally indicated at I0, cutting means II, rail means I2 for supporting and bowing the strip, and a stop mechanism generally indicatedas I3. For supporting the various operating components referred to above, a frame structure I 4 is provided and a driving mechanism I5 including a driving motor I6 is provided for furnishing power for operation of the machine. The frame structure I4 includes means for supporting a roll of strip material 2D which may be metal such as aluminum. A plurality of rollers 2|, 22, 23, 24 and 25 9 are provided for straightening the strip and guiding it through the machine. Annular rims 2G may be provided on the rollers as illustrated on rollers 22 and 23 for guiding the sheet into the machine. The feeding mechanism includes

additional rollers

28 and 29 which are driven by the driving mechanism I5 for feeding the strip 20 as will be further explained.

The strip 20 is fed along a support 30, under a movable shear blade 3| which is part of the cutting means II, and then along

tubular rails

32 and 33 which support the edges of the sheet. A third rail member 34 is supported above the

rails

32 and 33 by a frame member 35 which is a part of the frame structure I4 of the machine. The rail 34 includes an end 36 which is positioned above the

tubular rails

32 and 33 so that the strip 20 is fed therebetween. The forward end 31 of the rail 34 extends below the upper surface of the

tubular rails

32 and 33 so that as the strip is fed along the rails it is bowed down in the center` in a manner clearly shown in Fig. 5. The rail 34 is therefore interposed between

rails

32 and 33 so that the surfaces thereof which engage the strip bow the same. rIhis bowing of the strip across its width stiffens the strip lengthwise in a well known manner. The feeding mechanism ID feeds the strip 20 until it engages the stop I3 after which automatic controls cause the feeding mechanism to be disengaged from the driving means, the end of the strip 20 to be positively stopped, and the cutting mechanism to cut off the strip at the desired length. These automatic controls will be later described in detail.

It is pointed out here that the feeding mechanism, the cutting means, and the driving means are not in themselves a part of the invention and components of any standard construction can be used. Specifically, the various components of the driving mechanism such as the shafts, chain and belt drives, and clutches may 'be of any suitable construction and are illustrated only schematically to point out the manner in which the machine operates. Also, the specific construction of the feeding mechanism and cutting means are merely illustrative, and these components may take any other well known form. The over-all machine which includes these elements in combination with the rail means and the stop mechanism is, however, a part of the present invention. This machine also provides one structure by which the method of the invention can be practiced.

Referring now to the driving means I5 shown in Fig. 2, it is noted that the motor I6 is connected to shaft 40 through a belt 4I. Shafts 42 and 43 may be driven from shaft 40 by

chains

44 and 45, respectively. The feeding roller 28 is operatively connected to the shaft 40 by clutch 4B and the roller 29 is geared to the roller 28 so that the two rollers are simultaneously driven. The cutting means I I is adapted to be connected to the shaft 42 by clutch 41 and a control shaft 43 is connected to the shaft 43 by clutch 49. The cutting means includes a shaft 50 having a pair of cams 5I secured thereon which are adapted to engage projecting arms 52 secured to the shear blade 3 I. To permit movement of the shear blade 3l in a vertical direction, it is supported in guides 53. The blade is held in the normal upward position by springs 54 which bear against the pro- J'ecting arms 52, and when the shaft 50 is connected to the driving mechanism I5 by clutch 41, the cams 5i rotate so that the extending portions thereof bear against the projecting arms 52 to cause the shear blade 3I to move downwardly. The Iblade 3| cooperates with a stationary shear blade 55 to cut off the strip 20.

The rail means 32 and 33 are retractable to drop a sheet which has been cut off. These rails are supported by arms 6U pivotally supported on the frame structure I4. For moving the

rails

32 and 33, actuating bars 6I are provided which are arranged to be moved to the right (Fig. 2) to cause the rails to move to the left and to be withdrawn from under the edges of the sheet as will be apparent. The bars 6| are actuated by a lever 62 which is operatively connected to a cam 65 on the control shaft 48 by arms 63 and 64. The arm 64 extends vertically and is moved to the right by the projecting part, of the cam 65 when the shaft 48 is rotated. Springs 59 connected between certain of the arms 60 and the frame structure hold the

rails

32 and 33 in the normal position for supporting the strip 28. As illustrated in Fig. l, a iiat truck 68 can be positioned under the rail structure I2 so that as the

movable rails

32 and 33 are retracted the sheet which is cut off can be dropped thereon. Suitable guiding structures such as illustrated at G9 can be secured to the frame I4 so that the sheets are stacked in an even pile by the cutting machine.

Referring now to Fig. 3, the details of the stop mechanism I 3 will be described. The stop mechanism includes a base portion I0 which is adjustably supported on the frame member 35. This adjustment can be provided by making the base 'ID of a channel-shaped configuration which fits on the edge of the member 35 and providing a thumb screw l'I for holding the base in position. The stop is adjustably positioned along the support 35 so that sheets can be cut to any desired length as will be described. The stop includes a vertical portion 12 and a movable arm 13. The movable arm includes a plate 'I4 thereon which is positioned to be engaged by the end of the strip 20 as it is fed along the rail structure. A

switch 'I5 is provided on the vertical portion 12 having a movable contact member 'I6 adapted apanage,

to be operated by the movable. arm 13.. A pairV of springs 'H' and 1M. are provided on the. Contact member 1t. the springl T'l being positioned be.-A tween the movable arm, 1.31 anda rim 18 on the movable; contact 16 andthe spring 11a. being posiy tionedbetween the rim '[8y andthe. portion 'l2 of` the stop. v'The spring T1, stiier, than. the spring" 'tlc so. that as the arm 13, is engaged by the strip 2e the initial movement of the. arm will be transmitted through the spring 'il'. to the Contact 'it causing. thev switch 7.5 to. be closed.

Further movement of the arm. 'L3 is then absorbed by the spring Ti... Then movement of arm- ?3, isl limited by screw 19 adjustably positioned on the portion 'l2 of the stop which acts asvv a, positive stop to prevent furthe-r movement of the arm` 13.

Considering now the over-alloperation. of the machine, the strip 2.0. is fed along, the rails` 32 and 33 and is bowed. by action, of the rail, 3,4.. When the end of the. strip. engages theI arm 13 the switch l5, is closed` whichl provides a closed circuit through battery 8.!!r and solenoid 8| (Fig.A 2). clutch d8 which connects the. control shaft 48, to the driving mechanism. Cam 8.2- is,l therefore.. rotated and operates: through lever 83 to cause the clutch it to, be. disengaged thereby disengaging the feeding roll.. The lever 83. also, acts to engage brake Sii for stopping. the feeding mechanism. As the feeding mechanism hasl consid, erable momentum,. it. cannotr be stopped instan-- taneously by the. brake and the feeding of the stripy 20 will not stop. immediately but will continue and the end of the strip will move the.` armv 'F3 until it engages the screw 13 which. acts as a, positive stop., As the portion of the strip 2i) between the cutting` means. il and the stop i3 is bowed across its width., it. is` relatively rigid lengthwise`and the stopY i3. is, therefore, veffective to, preventl the feeding of additional mate,- rial past the cutting means. An-y additional material which is fed by thel feeding; mechanism after the strip 20 engages the positive stop` will.

accumulate between the feeding rollv 28 and the cutting means H causing the stripv tobuckle in, this space.v This actionisshown in Fig. 4 in which:

the strip. 2d is` shown buckled. upwardly in` the, region designated as S5..

After the feeding of the. strip 2d has stopped, the continued movement of. the control shaft 48 causesthe cam 86. thereon t0. Operate lever 81 which is effective to` engage clutch 47 for connecting the cutting mechanism to the driving means. As previously stated7 rotation of the cams 5l causes the blade- 3l` tobe moved downwardly to shear the strip 2,0, asshown-,in Fig. 4. Further rotation of the control shaft 48. causes the cam 65 to engage the arm. 6.1i which acts through arm S3, lever 52 and barsY 6.1, to. retract the

rails

32 and 33 causing the strip which is cut off to be dropped, As soon as the sheet is dropped, the arm 'i3' of the stop mechanism will be. released causing the solenoid to 'be deenergized and the control mechanism restored` to condition for cut,-

ting another sheet. The feeding mechanism opcrates to feed the strip onto, thezrail, structure again and the entire operationis automatically` repeated.

It is apparent, therefore, that the length ofthe:

sheetcut on is accurately determined by the DO.- sition, of' the. screw 19 which` forms aI positive` stop with respect to the-cutting means Hg.. This distance canbealtered by adjusting the positiony of the stop, along the sulJPOlit 35, and ne adj-ust.-l mentcan be obtained by adiustment;y of; the4 The solenoid is arranged to operate theV on, thev length of the,y sheet, being cut and the. ma,"A terial of the strip.` When usingrelatively heavy materiali: it is not. necessary to. bow the stripas muchv as when. using lighter material and,l therefore.. the, rail 34 wouldy be positioned dip.Y

ferently with. respectto. the, rails 32 and 33.v When,

making, a, very short. cut, it. would. be. necessary to provide a, shorter rail. 3.4V and likewise-.in making. a very long cut,. a longer rail. might, be required. As the. rail 34 is. adjustably positioned on the support 3`5 by bolts 9.0, and nuts 91 it is obviousl that by providing a plurality of. holes in the support 35, the position of.. the rail can be easily changed and longer or shorter rails. can be very easily substituted'.

In Figs. l and 3 there, is illustrated a.v counter 93 which may be. used. with the. stop. mechanism it; rThis counter includes. an arm. 94M connected through spring 96. to an, arm 95.011 the movable arm 73; of the, stop mechanism. Movement of the arzn 'it will be transmitted through the spring` St to cause movement. of arm 94` which actuates the counting mechanism.4 Such acounter may be,

of any standard type. havingan actuating arm which can be, coupled to the moving arm- 13. of the stop. It is apparent. that. such a, counter would indicate the number of sheets which are, cut from the strip 2li., As. themachine. is; fullyautomatic and cuts sheets rapidly with very little attention, the use of such a counter. maybe very desirable to keep account, of the sheets out.`

lit is, therefore, seen that there, isI provided an improved method for cuttingI sheets, from; strips of material which is effective to cut sheets to very accurate lengths.. A new cutting machine for practicing this methodis-also` provided.. Although the machine has beenV described as suitable for cutting an, aluminum strip provided on. a roll, it is apparent thatit would be suitable for cutting sheets from. strips: of other material whether metallic orl not as longv as the material is suiciently stiff that bowing, ofI thesameitends. to make it rigid thereby permittingthe movement. of the strip tol be positively'stopped whenthe end thereof moves the arm T3: in engagement with. the positive stop.- 19.

Cuttingy machines in. accordance with the. in vention have been constructedy and have been. fcundvery satisfactory in actual use; When cutting, sheets trom. anA aluminum. strip, the machines have been found to. cut. sheetsin lengthsv up to 12 feet with anerron ofonly figofV an inch; This is more accuratethan other machines available including the, much more complicatedA ma chinessuch as the dying shears. The machine cuts the sheets rapidly. and requires practically no attention, oneoperator being' able to operate a plurality of machines at theisame time. As the machine stacks thev4` cut sheets onV a truck they can. be easilyfmoved foi-shipping' or further processing.

While havedescribedv one embodiment whichv is illustrative of my invention, it is' obvious that variousl changes and modifications can be made therein without departing from` the intended scope offthe invention as defined in' the appended claims.

I claim:

l. A. machine for-close tolerance cutting; of"

sheets. from a strip of" mater-iai; comprising;` rail' means for supporting saidfstrip, cutting means.

positioned at one end offsaid'rail'means, a stop the essaim-ii of?. fait,

mechanism positioned at the other end of said rail means, and a feeding mechanism for feeding said strip past said cutting means and along said rail means, said rail means including a pair of side rails for supporting the edges of the strip on the under side thereof and a center rail positioned to engage the top surface of said strip, said center rail having a bottom surface extending below the level of the top surfaces of said side rails to bow said strip downward across its width so that the portion of said strip between said cutting means and said stop mechanism is relatively rigid.

2. A machine for close tolerance cutting of sheets from a strip of material comprising, rail means for supporting said strip, cutting means positioned at one end of said rail means, a stop mechanism positioned at the other end of said rail means, a feeding mechanism including driving means for feeding said strip past said cutting means and along said rail means, said rail means including retractable side rails for supporting the under surface of said strip and an intermediate rail engaging the upper side of said strip and including a surface extending below the level of the-top surfaces of said side rail to bow said strip across the width thereof to stiifen the same, and a control system associated with said stop mechanism and arranged to stop said feeding mechanism, actuate said cutting means and retract said rail means so that a sheet of the desired length is cut off and dropped by said machine.

3. A machine for close tolerance cutting of sheets from a strip of material including in combination, rail means extending longitudinally of said strip, cutting means positioned at one end of said rail means, a feeding mechanism including disengageable driving means for feeding said strip past said cutting means and along said rail means, said rail means including portions positioned to engage upper and lower sides of said strip with the portions engaging the upper side of said strip extending below the portions engaging the lower side thereof, to bow said strip across the width thereof during the cutting operation to thereby stiffen the same, a stop mechanism including a movable arm positioned at the other end of said rail means in the path of said strip and a positive stop which limits the move.. ment of said arm to stop the movement of said strip past said cutting means, and a control system for disengaging said driving means from said feeding mechanism when the end of said strip engages said movable arm, said control system being effective to actuate said cutting means when the movement of said strip has stopped.

4. A machine for close tolerance cutting of sheets from fiat strip material comprising, rail means extending longitudinally of said strip, cutting means positioned at one end of said rail means, a stop mechanism including a movable arm positioned at the other end of said rail means, a feeding mechanism spaced from said cutting means for feeding said strip past said cutting means and along said rail means, said feeding mechanism including driving means and a brake and having considerable momentum so that an interval of time is required for stopping the same after said driving means is disengaged therefrom and said brake is applied, said rail means including portions positioned to engage upper and lower sides of said strip with the portions engaging the upper side of said strip extending below the portions engaging the lower side thereof, to bow said strip vacross the width thereof to ineke the portion of the strip extending between said cutting means and said stop mechanism substantially rigid, during the cutting operation, and a control system for disengaging said driving means from said feeding mechanism and for applying said brake when the end of said strip engages said movable arm, said stop mechanism including a positive stop which limits the movement of said arm and thereby stops the movement of said end of said strip at a predetermined position so that any additional strip material which is fed before said feeding mechanism stops accumulates between said feeding mechanism and said cutting means, said control system being adapted to actuate said cutting means when movement of said strip is stopped.

5. A machine for close tolerance cutting of sheets from flat strip material having relatively wide face surfaces including in combination, first and second elongated rail means extending 1ongitudinally of said strip material on either side thereof, cutting means positioned at one end of said rail means, a stop mechanism including a movable arm positioned at the other end of said rail means, a feeding mechanism spaced from said cutting means and including disengageable driving means for feeding said strip material past said cutting means and along said rail means, said feeding mechanism havingr considerable momentum so that an interval of time is required for stopping the same after said driving means is disengaged therefrom, said first rail means having surface portions engaging said strip material on one side thereof, said second rail means having surface portions engaging said strip material on the other side thereof and extending beyond said surface portions of said rst rail means to bow said strip material across the width thereof along the entire longitudinal portion thereof extending between said cutting means and said stop mechanism to make the same substantially rigid during the cutting operation, and a control system for disengaging said driving means from said feeding mechanism when the end of said strip material engages said movable arm, said stop mechanism including a positive stop which limits the movement of said arm and thereby stops the movement of said end of said strip material at a predetermined position so that any additional strip material which is fed before said feeding mechanism stops accumulates between said feeding and said cutting means.

6. A machine for close tolerance cutting of sheets from flat strip material having relatively wide face surfaces including in combination, first and second elongated rail means extending longitudinally of said strip material for supporting the same, cutting means positioned at one end of said rail means, a stop mechanism positioned at the other end of said rail means, a feeding mechanism spaced from said cutting means and including disengageable driving means for feeding said strip material past said cutting means and along said rail means, said feeding mechanism having considerable momentum so that an interval of time is required for stopping the same after said driving means is disengaged therefrom, said first rail means including a pair of rails positioned longitudinally of said strip material having surfaces defining a plane which engage one face surface of said strip, said second rail means having surface portions engaging the other face surface of said strip material and extending from said plane in the direction of said pair or rails and in the space therebetween, said rail means bowing said strip material across the width thereof along the entire portion thereof extending between said cutting means and said stop mechanism to make the same substantially rigid during the cutting operation, and a control system for disengaging said driving means from said feeding mechanism when the end of said strip material engages said stop mechanism, said stop mechanism including a positive stop which limits the movement o said strip material at predetermined lposition so that any additional strip material which is fed before said feeding mechanism stops accumulates between said feeding means and said cutting means.

7. A machine for close tolerance cutting of sheets from fiat strip 1nateria1 having relatively wide face surface including in combination, rail mains extending longitudinally of said strip material for supporting the same, cutting means positioned at one end of said rail means, a stop mechanism positioned at the other end of said rail means and spaced with respect to said cutting means to establish the length of the cut sheets, a feeding mechanism spaced from said cutting means for feeding said strip material to said cutting means and past said cutting means along said rail means to said stop mechanism, said feeding mechanism together with the strip material having considerable momentum so that an interval of time is required for stopping the same, said rail means including a plurality of rails positioned longitudinally of said strip material and having portions interposed between each other with surfaces thereof engaging opposite face surfaces of said strip to bow the same across the width thereof throughout the entire length of the portion of said strip material extending between said cutting means and said stop mechanism to render the said portion substantially rigid longitudinaliy during the cutting operation, and a control system for said feeding mechanism rendered operative when the end oi said strip material engages said stop mechanism to stop said feeding mechanism, said stop mechanism including means for positively stopping the end of said strip material when said end reaches a predetermined position, the portion of said strip material between said feeding mechanism and said cutting means being freely supported allowing the same to bow longitudinally so that any strip material which is fed after said end thereof has reached said predetermined position accumulates between said feeding mechanism and said cutting means.

8. A machine for close tolerance cutting of sheets from at strip material having relatively wide face surfaces including in combination, rail 10 means extending longitudinally ci said strip material for supporting the same, cutting means positioned at one end of said rail means, a stop mechanism positioned at the ether end of said rail means and spaced with respect to said cutting means to establish the length ci the cut sheets, a feeding mechanism spaced from said cutting means for feeding strip material to said cutting means and past said cutting means along said rail means to said stop mechanism, said feeding mechanism together with the strip material having considerable momentum so that anv interval ef time is required for stopping the same, said rail means including spaced lower rails having tcp surfaces engaging one face surface of said strip material and an upper rail positioned be'- tween said lower rails and having a bottom surface extending below the top surfaces of said lower rails and engaging the other face surface of said strip material, to bow said strip material across the width thereof throughout the entire length of the portion thereof extending between said cutting means and said stop mechanism to render the said portion substantially rigid longitudinally during the cutting operation, and a control system for said feeding mechanism rendered operative when the end of said strip material engages said stop mechanism to stop said feeding mechanism, said stop mechanism including means for positively stopping the end of said strip material when said end reaches a predetermined position, the portion of said strip material between said feeding mechanism and said cut` ting means being freely supported allowing the same to bow longitudinally so that any strip material which is fed after the end of said strip has reached said predetermined position accumulates between said feeding mechanism and said cutting means, said control system actuating said cutting means when movement of said strip material has stopped and 'thereafter causing said feeding mechanism to feed said strip material for the next sheet.

MATI-IIAS J. FEY.

References enea in the sie of uns patent UNITED sTATEs PATENTS Number Name Date 1,738,076 Molins Dec. 3, 1929 1,834,004 Overbury et al Dec. 1, 1931 1,840,997 Yeager Jan. 12, 1932 2,158,790 Arthur May 16, 1939 2,262,550 Hunter Nov. 11, 1941 2,269,714 Fenton Jan. 13, 1942 2,382,406 Engberg Aug. 14, 1945 2,444,465 Peters July 6, 1948