US2766665A - Apparatus for applying tear strings to wrappers - Google Patents

Description

Get. 15, 1956 F. c. VAN ARSDELL 2,756,565

APPARATUS FOR APPLYING TEAR STRINGS TO WRAPPERS Filed March 26, 1953 5 Sheets-Sheet 1 IN VEN TOR.

BYFREED c. VAN ARSDELL A-TTYS APPARATUS FOR APPLYING TEAR STRINGS TO WRAPPERS Filed March 26, 1953 F, C. VAN ARSDELL 5 Sheets-$heet 2 INVENTOR lg ARSDELL BY MN wk. ON mm FRED C.

ATTYS Oct. 116, 1956 F. c. VAN ARSDELL APPARATUS FOR APPLYING TEAR STRINGS TO WRAPPERS 5 Sheets-Sheet 3 Filed March 26, 1953 C. VAN ARSDELL FRED fl i v M ATTYS.

Oct. 16, 1956 F. c. VAN ARSDELL 2,766,665

APPARATUS FOR APPLYING TEAR STRINGS T0 WRAPPERS Filed March 26, 1953 5 Sheets-Sheet 4 n4 ms 63 54 54 53 22 9s 96 97 95 95 INVENTOR. D FRED c. VAN ARSDELL FIG. IO 74m ATTYS Oct. 16, 1956 F. c. VAN ARSDELL 2,766,665

APPARATUS FOR APPLYING TEAR STRINGS TO WRAPPERS 5 SheetsSheet 5 Filed March 26, 1953 Pie. 9

INVEN TOR. FRED C. VAN ARSDELL ATTYS United States Patent APPARATUS FOR APPLYING TEAR STRINGS T WRAPPERS Fred C. Van Arsdell, Medina, Ohio, assignor to The Quaker Oats Company, Chicago, 11L, a corporation of New Jersey Application March 26, 1953, Serial No. 344,842

11 Claims. ((31. 931) The invention relates generally to apparatus for applying tear strings to wrappers orlabels and more particularly to apparatus for applying tear strings in proper position on spaced-apart wrappers lying flatwiseon a conveyor and moving continuously toward the packages 'or containers to which the wrappers are to be applied.

There are many forms of prior apparatus for applying tear strings or strips to various wrappers for containers, or to the containers under the wrappers. Certain of these are complicated machines which move the wrappers step-by-step so that the strings can be first applied to the wrappers and then cut off with a desired overhang of the string at one end of the wrapper.

Certain other prior machines are further complicated by the required operations ofpressing the tear strings onto adhesively coated flaps or the like, and thereafter cutting of the strings with projecting or overhanging ends. In other machines the string is fed continuously through feed rolls in a taut condition, and is then cut to length with or adjacent to the wrappers as they move into position. This construction requires complex cutting and correlating mechanisms.

in all prior tear string applying apparatus of which I am aware, a number of disadvantages are present among which are the difficulties in maintaining the string in straight condition while it is made to adhere ;to a continuously moving wrapper and cut off with the proper amount of overhang.

It is an object of 'the present invention to provide a novel and improved apparatus which will cut off the tear strings and then apply them linearly and in proper'relative positions to continuously moving spaced-apart Wrappers.

Another object is to provide a novel and improved apparatus for applying tear strings to wrappers, which apparatus does not require separate feeding, cutting and tensioning-devices for the tearstring, or special mechanism for pressing the tear .string on to the wrappers or adhesively coated flaps thereof.

Afurther object is to provide a novel and improved apparatus for applying tear strings to wrappers, which apparatus is simple, compact and inexpensive -to-make and to maintain, and which overcomes the disadvantages of prior machines for accomplishing the same or similar purposes.

These and other objects are accomplished by the parts and combinations and arrangements of parts comprising the present invention, a preferred embodiment-of which is shown and described herein by way of example, various changes and modifications in details of construction being contemplated within the scope of the invention as defined in the appended claims.

In the drawings:

Fig. 1 is an elevational view, as on line 11, Fig. 6, of the novel apparatus mounted in operative relation to a conveyor belt carrying spaced-apartwrappers;

Fig. 2 is a plan sectional view on line 2-2, Fig. '1;

arms 15 on one side of the belt.

Fig. 2a is an enlarged fragmentary section through the 'big'ht of the tear string feed rolls;

Fig. .3 is a fragmentary sectional view, as-on line 33, Fig. 1;

Fig. 4 is a fragmentary sectional view, as on line 4-4, Fig. 1;

Fig. 5 is a fragmentary sectional view, as on line 55, Fig. 1;

Fig. 6 is an end elevation on line 66, Fig. 1;

Fig. 7 is an enlarged sectional view on line 7 7, Figs. 2 and 6;

Fig. 8 is an enlarged sectional view on line 88, Fig.6;

Fig. 9 is a plan view substantially on line 9-"9, Fig. :6; and

Fig. 10 is a wiring diagram for. the improved apparatus.

The novel apparatus for applying tear strings to wrappers is preferably used iniconjunction with an automatic wrapping machine of well known construction in which adhesive is applied to one side of the wrappers and they are then deposited, adhesive side up, .on a continuously moving conveyor belt which feeds them into mechanism for automaticallyapplyingthe wrappers to the packages. InFigs. 1, .6 and 9 of the drawings, a section-of the conveyer belt 1d carrying the wrappers -W is shown where it passes the tear string applying apparatus. The conveyor .belt 11 is carried on the usual rollers 12 having guide flanges 13 .at their ends and 'journaled in suitable bearings 14 mounted in bracket arms 15 supported on a suitable frame 16. As shown, the wrappers Ware deposited on the belt 11 with the front marginal portion of the wrappers overhanging the front'edge of the belt.

The tear string applying apparatus includes a base 17 secured by bolts l8-on the horizontal flanges of bracket An upright web 19 rises from the base 17, and diverging upwardly therefrom is a shaft mounting front flange 26 and a shaftmounting rear flange 21. Parallel shafts .22 and 23, spaced longitudinallyof-the belt and extending laterally at right angles from one side thereof, are journaled in anti-friction bearings 24 mounted in the flanges 2t! and 21 respectively.

The front end of shaft 22 has a tapered portion 25 on which the hub 26 of a circular-roll or disk 27 is mounted by means-of a nut 28. Similarly the front end of shaft 23 has a tapered portion 29 on which the hub 30 of a circular roll or disk 31 is mounted by means of a nut 32. .The rolls 27and 31 are of substantially equal diameters and are mounted with their peripheries almost in abut- .ment, the periphery of roll 27 being :fiat while theperiphslight clearance is maintained between the rolls, of the orderof .004 inch, so that the-string in passing through the 'bight of the rolls is slightly compressed without crushing.

-At-one point on'its periphery the roll27 has alkriife 34 which is part of a removable insert 35 attached :to the face of the roll by screws 36. At a mating point on its periphery roll 31 has an anvil 37 having a'transverse groove or recess adapted to receive .the projecting end .of the knife.3:4 as the rolls .27 and .31 are rotatedin opposite directions atthe same speed. The anvil 37 is part of an insert 38 removably attached to the :face of the roll .31 by screws 39. Thus the roll 27 may beca'lled the knife roll and the roll 31 may be called the anvil roll.

The I011 27 is rotated clockwisezand theirollfil is rotated counterclockwise. The means for rotating the roll 27 .preferablycomprises a sprocket '46 mounted on the rear extension of shaft22and driven by a chain dloperatively connected .toa suitable motor (not shown). The ;means on shafts 22 and 23 respectively. The gears 42 and 43 mesh with each other and have the same number of teeth.

A single revolution clutch of conventional construction is mounted on the rear extension of shaft 22 for operating the shaft intermittently. As shown in Fig. 2, the driving member 45 is keyed to the sprocket 40 by key 46 and is journ'aled on the shaft. The inner driven member 47 is keyed on shaft 22 by key 48, and a cam ring 49 is secured to member 47 and located within a series of rollers 50 carried in a cage 51. The cage is operatively connected to a trip cam 52 (Fig. 7), which has a step 53 in its outer periphery normally engaged by a. trip lever 54 and rockable by a spring 55 when released.

As long as the trip lever 54 engages the step 53, the clutch is released, the driving member 45 turning continuously with the sprocket 40 while the driven member 47 and shaft 22 remain stationary. When the lever 54 is withdrawn, the spring 55 rocks the trip cam 52 which rotates the roller cage 51 to move the rollers into driving engagement with cam ring 49, and the shaft 22 rotates with the driving member 45 until the trip lever again engages the step 53, which in this case is after one revolution of the shaft.

The means for actuating the trip lever 54 preferably comprises a solenoid 57 mounted by sleeves 58 on a bracket arm 59 extending angul'arly from the base 17. As best shown in Fig. 7, a trigger arm 60 is pivoted at 61 to the armature bar of the solenoid, and has a hook notch 62 for engaging a catch 63 on the rear end of .the trigger arm. The trigger arm is pivoted at 64 on a mounting plate 65 which is supported on the base 17 and secured by screws 66 to a boss 67 projecting rearwardly from the rear shaft supporting flange 21.

When the solenoid is de-energized, the arm 60 is pulled by spring 68 up against the stop 66', as shown in the dot-dash position in Fig. 7, with the catch 63 in notch 62 and the other end of lever 54 pulled down by spring 69 to engage the step 53 of the cam and hold the clutch disengaged. When the solenoid is energized, the arm 60 is pulled down and the hook pulls down on the catch 63 to first trip the outer end of lever 54 and release the cam, engaging the clutch. As the hook continues to be pulled down, lever 54 rotates about the pivot 64 and the knob 54 engages the upper end of the arm 60 sufficiently to allow the hook to slip below the catch 63, as shown in the full line position of Fig. 7, where the spring 69 pulls the outer end of lever 54 down so as to ride the cam 52 and be in position to again engage the step 53 at the end of one revolution and disengage the clutch. By thus freeing the catch 63 from the hook 62 after the lever is tripped, it is insured that the clutch is always disengaged at the end of one revolution even though the action of the solenoid may be relatively slow.

As shown in Fig. 6, the tear string supply is a spool or spools 70 positioned in a usual housing, the string S being led through an eye in the top of the housing through tensioning means indicated generally at 71 and thence through a front guide arm 72 to a feed tube 73 which directs the string into the V-groove 33 of the anvil roll 31. The tensioning means 71 may consist of a string straightening strap 74 having spaced eyelets through which the string is laced, and a conventional sewing machine tensioning device 75. The guide arm 72 and feed tube 73 are preferably mounted on a front .mounting plate 76 positioned behind the upper portions of the rolls 27 and 31, and carried on the upper end of front flange 20 by spacers 77.

The feed tube 73 is carried in a boss member 78 secured to the plate 76 so that the delivery end of the tube is in exact registry with the V-groove 33 of roll 31 and terminates just above the roll 31 near the bight between rolls 27 and 31. Immediately below the delivery end of tube 73 is a flanged roller 79 abutting the periphery of the roll 31 (Fig. 3) for maintaining the string S in the the front edge of the belt.

groove 33 after the string is cut off at the bight of the rolls by conjunction of the knife and anvil. The roller 79 is journaled on the lower end of an arm 80 pivoted at 81 on the mounting plate 76 and yieldingly urged against the roller 31 by a spring '82 connecting the upper end of arm 80 to a stud 83 screwed into the mounting plate.

The roller 79 functions to hold the string against roll 31 when the string is started through the rolls, and also if the string below the roller should break or become fouled in any manner.

A front guide plate 84 preferably of transparent plastic material is hingedly mounted immediately in front of the rolls 27 and 31. As seen in Fig. 1, the plate 84 is of substantially inverted T shape with the top of the stem secured to a mounting arm 85 by screws 86 (Fig. 4), the arm being secured to the lower section of a spring hinge 87, the upper section of which is mounted on an arm 89. The upper end of the arm 89 is secured by set screw 90 in the front end of a spacer stud 91 mounted on mounting plate 76. Thus the path of the string below the bight of the rolls can be observed through the plastic plate 84, and the plate may be swung outwardly about the hinge 87 at any time to gain access to the space below the bight of the rolls.

A rear guide plate 92, which may be of brass, is mounted behind the rolls 27 and 31, preferably being secured on the front surface of mounting plate 76 by screws 93. Also secured on the front surface of the mounting plate 76 by screws 94 are electric heater housings 95, one adjacent to the rear surface of each of the rolls 27 and '31. These housings carry electric heaters 96 which maintain the rolls at substantially constant temperature conducive to maintaining the string S in a linear condition as it is dropped from the bigh-t of the rolls.

The energizing of the solenoid 57 is controlled by a photo-electric cell 97 which is positioned below the front edge of the belt 11, as shown in Figs. 6 and 9. The cell 97 is of usual and well known construction having a target or eye 98 which is positioned so that it is intermittently covered by the front overhanging portions of the wrappers, but extends out in front of the plane of The cell 97 is mounted in a bracket 99 which is mounted on the bracket 15 for adjustment longitudinally of the belt by means of a screw 100 extending through a slot 101 in the bracket.

A light source 102 for directing a beam of light vertically downward at the target 98 of the cell is adjustably mounted on a suitable bracket 103 above the front bracket arm 15 carrying the belt rollers 12. Referring to Fig. 8, the light source 102 is mounted on a slide bar 104 carrying a pinion 105 meshing with a rack bar 106 secured on the mounting plate 107 of the bracket 104. A hand wheel 108 is provided for turning the pinion to adjust the slide bar and light source, and a Vernier scale 109 indicates the amount of adjustment.

Referring to Fig. 10, the cell 97 is electrically connected by means of a usual plug 110 to a photo-electric relay 111 in circuit with the solenoid represented schematically at 57 operatively connected to the trip lever 54 which controls the single revolution clutch cam 52. The relay 111 is connected to the conductors 112 and 113 of a current supply, and also connected to said current supply by conductors 114 and 115 is a suitable transformer 116 supplying current to the light source 102, there being a suitable switch 117 in conductor 115. The heaters 96 may be connected in series to the conductors 114 and 1-15.

In the operation of the apparatus, as the wrappers W move continuously under the beam from the light source 102, when the overhanging portion of a wrapper interrupts the beam, the photo-electric relay 111 is energized, completing a circuit through the solenoid 57. When the solenoid is thus energized it actuates the trip lever 54 and releases the cam plate 52 of the clutch, =allowing it to rotate the feed rolls 27 and 31 to feed the string S downwardly through the bight of the rolls. When the rotation of the rolls brings the knife 34 and anvil 37 together the string will be cut oil and the cutoff piece S will drop onto the wrapper W which is under the rolls. Once the trip lever 54 has released the cam 52, the lever will ride the cam until it completes one revolution, when it will drop behind the step 53 and disengage the clutch. As the lower end of the string S strikes the longitudinally moving wrapper, it is carried forward and the string S is laid linearly or longitudinally in a straight line .along the top surface and near the rear edge of the wrapper, as indicated in Fig. 1. Since the wrappers are placed on the conveyer with their upper surfaces covered with wet adhesive, the string will remain in linear position until the wrapper is applied to the package or container.

Preferably, a guard bar 118 is mounted at its upper end on mounting plate 76 by a bolt 119, and extends arcuately downwardly under the roll 27, to protect the roll 27 should any of the wrappers W tend to rise above the belt 11 due to air currents and the like.

A friction brake is provided for roll 31 to overcome the backlash of the rolls when the clutch is suddenly disengaged by the lever 54 striking the step '53 on the clutch cam. The shoe 120 of the brake bears against the periphery of roll 31 and is movably mounted on a plate 121. The shoe is urged against the roll by a spring 122. The amount of compression of spring 121 is adjusted by a screw 123. Without the brake, every time the clutch is stopped the backlash of the rolls tends to form a small loop in the string between the roller 79 and the bight of the rolls.

The diameters of rolls 2'7 and 31 are-calculated to feed in one revolution a length of string S substantially equal to the length of a wrapperW, and the speed of rotation of the rolls is equivalent to the linear speed of the belt 11 so that a cut off length S will be deposited on each wrapper. Also, the photo-electric cell 97 and the light source 1&2 are positioned in proper longitudinal relation to the rolls so that the cut ofi pieces S slightly overhang the rear edges of the wrapper. This overhanging portion projects from the wrapped article and provides a pull piece to start the tearing operation when opening the wrapper.

The improved apparatus is relatively simple in construction and operation because the feed rolls 27 and 31 feed, cut off and deposit a length of string in proper linear position on a moving wrapper, and with'the desired amount of overhang. No separate cutting, tensioning, and string pressing or applying devices are required, and the necessity of correlating such devices is eliminated. Moreover, the speed of the machine is rapid because the movement of the wrappers is continuous, the tear strings being applied to the wrappers in motion. Speeds approaching 120 wrappers per minute have been successfully attained with tear strings properly applied, by means of the novel apparatus of the present invention.

The terms used in the foregoing specification have been used descriptively for the sake of clarity, and no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art.

What is claimed is:

1. In combination with a belt conveyor carrying spaced-apart wrappers projecting laterally beyond one edge of the belt, apparatus for depositing a length of string linearly on each wrapper including, a pair of feed rolls spaced above and disposed longitudinally of the belt, the bight of said rolls adapted to feed string downwardly so as to fall on said belt, means for feeding string into the bight of the rolls, cooperating cutting means on the peripheries of the rolls, means for driving the rolls at peripheral speeds equal to the linear speed of the belt, and clutch means controlled by the movement of each wrapper to operate the driving means -.to rotate the rolls, 'whereby a length of string is cut OE and deposited linearly on said mapper.

2. In combination with a belt conveyor carrying spaced-apart wrappers projecting laterally beyond one edge of the belt, apparatus for depositing .a length of string linearly on each wrapper including, a pair of feed rolls spaced above and disposed longitudinally of the belt, the bight of said rolls adapted to feed string downwardly so as to fall on said belt, means for feedingstring into the bight of the rolls, a knife projecting from the periphery of one roll, a cooperating anvil recessed in the periphery of the other roll, means for driving the rolls at peripheral speeds equal to the linear .speed of the belt, and clutch means controlled by the movement of each wrapper to operate the driving means to rotate the rolls, whereby a length of string is cut off and deposited linearly .on said wrapper.

3. In combination with -a belt conveyor carrying spaced-apart wrappers projecting laterally beyond one edge of the belt, apparatus for depositing a length of string linearly on each wrapper including, a pair of feed .rolls spaced above and disposed longitudinally .of the belt, the bight of said rolls adapted to feed string downwardly so as to fall on said belt, means for feeding string into the bight of the rolls, cooperating cutting means on the peripheries of the rolls, means for driving the rolls at peripheral speeds equal to the linear speed of the belt, a

single revolution clutch for connecting the driving means to said rolls, and means automatically engaging said clutch to operate the feed rolls in timed relation to said wrappers, whereby a measured length of string is cut off and deposited linearly=on each wrapper.

4. In combination with a belt conveyor carrying spaced-apart wrappers projecting laterally beyond one edge of the belt, apparatus for depositing a length of string linearly on each wrapper including, a pair of feed rolls spaced above and disposed longitudinally of the belt, the :bight of said rolls adapted to feed string downwardly so as to fall on said belt, means for feeding string into the bight of the rolls, a knife projecting from the periphery of one roll, a cooperating anvil recessed in the periphery of the other roll, means for driving the rolls at peripheral speeds equal to the linear speed of the belt, a single revolution clutch for connecting the driving means to said rolls, and means automatically engaging rolls spaced above and disposed longitudinally of the belt, the bight of said rolls adapted to feed string downwardly so as to fall on said belt, means for feeding string into the bight of the rolls, cooperating cutting means on the peripheries of the rolls, means for driving the rolls at peripheral speeds equal to the linear speed of the belt, a single revolution clutch for connecting the driving means to said rolls, means automatically engaging said clutch to operate the feed rolls in timed relation to said Wrappers whereby a measured length of string is cut off and deposited linearly on each wrapper, and a friction brake yieldingly abutting the rolls to overcome backlash when the clutch is disengaged.

6. In combination with a belt conveyor carrying spacedapart wrappers projecting laterally beyond one edge of the belt, apparatus for depositing a length of string linearly on each wrapper including, a pair of feed rolls spaced above and disposed longitudinally of the belt, the bight of said rolls adapted to feed string downwardly so as to fall on said belt, means for feeding string into the bight of the rolls, a knife projecting from the periphery of one roll, a cooperating anvil recessed in the periphery of the 7 other roll, means for driving the rolls at peripheral speeds equal to the linear speed of the belt, a single revolution clutch for connecting the driving means to said rolls, means automatically engaging said clutch to operate the feed rolls in timed relation to said wrappers whereby a measured length of string is cut oft and deposited on each wrapper, and a friction brake yieldingly abutting the rolls to overcome backlash when the clutch is disengaged.

7. In combination with a belt conveyor carrying spacedapart wrappers projecting laterally beyond one edge of the belt, apparatus for depositing a length of string linearly on each wrapper including, a pair of feed rolls of equal diameter spaced above and disposed longitudinally of the belt, said rolls having substantially abutting peripheries at least one of which has a peripheral string groove, the bight of the rolls adapted to feed string downwardly so as to fall on said belt, means for feeding string into the groove, an anvil on the grooved roll having a transverse groove intersecting said peripheral groove, a knife on the periphery of the other roll to enter said transverse groove and sever a length of string, means for driving the rolls at peripheral speeds equal to the speed of the belt, and clutch means controlled by the movement of each wrapper to operate the driving means whereby a measured length of string is cut off and deposited linearly on each wrapper.

8. In combination with a belt conveyor carrying spacedapart wrappers projecting laterally beyond one edge of :the belt, apparatus for depositing a length of string linearly on each wrapper including, a pair of feed rolls of equal diameter spaced above and disposed longitudinally of the belt, said rolls having substantially abutting peripheries at least one of which has a peripheral string groove, the bight of the rolls adapted to feed string downwardly so as to fall on said belt, means for feeding string into the groove, means for driving the rolls in opposite directions at peripheral speeds equal to the speed of the belt, an anvil on the grooved roll having a transverse groove intersecting said peripheral groove, and a knife on the periphery of the other roll to enter said transverse groove whereby rotation of said feed rolls will cut off a length of string being fed downwardly from the bight of said rolls.

9. In combination with a belt conveyor carrying spacedapart wrappers projecting laterally beyond one edge of the belt, apparatus for depositing a length of string linearly on each wrapper including, a pair of feed rolls of equal diameter spaced above and disposed longitudinally of the belt, said rolls having substantially abutting peripheries at least one of which has a peripheral string groove, the depth of said groove being slightly less than the normal diameter of the string, the bight of the rolls adapted to feed string downwardly so as to fall on said belt, means for feeding string into the groove, means for driving the rolls in opposite directions at peripheral speeds equal to the speed of the belt, an anvil on the grooved roll having a transverse groove intersecting said peripheral groove, and a knife on the periphery of the other roll to enter said transverse groove whereby rotation of said feed rolls will cut off a length of string being fed downwardly from the bight of said rolls.

10. In combination with a belt conveyor carrying spacedapart wrappers projecting laterally beyond one edge of the belt, apparatus for depositing a length of string linearly on each wrapper including, a pair of feed rolls of equal diameter above the conveyor having substantially abutting peripheries at least one of which has a peripheral string groove, the bight of the rolls adapted to feed string downwardly so as to fall on said belt, means feeding string into said groove between the rolls, a holding roller yieldingly pressing said string into said string groove immediately above the bight of the rolls, a transverse anvil recess in the periphery of the grooved roll, and a knife projecting from the periphery of the other roll to enter said anvil recess whereby rotation of the feed rolls will out ed a length of string being fed downwardly from the bight of the rolls.

11. In combination with a belt conveyor carrying spacedapart wrappers projecting laterally beyond one edge of the belt, apparatus for depositing a length of string linearly on each wrpper including, a pair of feed rolls of equal diameter above the conveyor having substantially abutting peripheries at least one of which has a peripheral string groove, the bight of the rolls adapted to feed string downwardly so as to fall on said belt, a feed tube conducting string into said string groove above the bight of the rolls, a holding roller yieldingly pressing said string into said groove between the bight and said feed tube, a transverse anvil recess in the periphery of said grooved roll, and a knife projecting from the periphery of the other roll for entering said anvil recess whereby rotation of the feed rolls will cut oif a length of string being fed downwardly from the bight of the rolls.

References Cited in the file of this patent UNITED STATES PATENTS 1,716,594 Metcalf June 11, 1929 1,978,035 Thom Oct. 23, 1934 2,060,450 Steen Nov. 10, 1936 2,130,729 Burns Sept. 20, 1938 2,165,289 Milmoe et a1 July 11, 1939 2,202,503 Milmoe May 28, 1940 2,248,744 Cohen July 9, 1941 2,334,030 Ranney et al Nov. 9, 1943 2,350,244 Malhiot May 30, 1944 2,542,282 Lissimore Feb. 20, 1951 2,561,485 Sillars July 24, 1951 2,574,181 Hess Nov. 6, 1951 2,575,887 Nitchie Nov. 20, 1951

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