US2460782A - Conveying means for shoe manufacture - Google Patents

Description

2 Sheets-Sheet 1 B. T. GIALDINI CONVEYING MEANS FOR SHOE MANUFACTURE Feb. l, 1949.

Filed sept. 2. 1944 INVENTOR.

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Feb. 1, 1949. B. T. GIALDINI CONVEYING MEANS FOR SHOE MANUFACTURE 2 Sheetsf-Sheet 2 Filed Sept 28, 1944 @l 9g f www INVENTOR.

`the time spent in pushing racks Patented Feb. l, 1949 UNITED STATI-:s PATENT OFFICE CONVEYING MEANS FOR SHOE MANUFACTURE Bruno T. Gialdini, Larchmont, N. Y. Application September 28, 1944, Serial No. 556,188

12 Claims.

`1 invention relates to means for facilitating and coordinating the various operations to be performed in the manufacture of shoes.

Reference is made to Patent 2,114,486 issued April 19, 1938, in my name. Prior to the date of the application for that patent, it had been the usual practice to locate the various machines for shoe manufacture along windowed walls while thecentral part of the factory floor space is occupicd by shoe racks. The shoes in various stages of completion were handled on these large wheeled racks, holding 72 pairs or multiples thereof.

For many operations, the time spent in taking shoes from diierent levels of the racks and transferring them to the machine and back again was as great as the time spent in actual operations upon the shoes. The racks were incapable of presenting all of the shoes in positions of convenient access so that the operator will have a short reach. The rising, stepping and stooping which the operator had to do was fatiguing part of his days work.

It was usually the duty of each operator iinishing his operation on all of the shoes in his rack to wheel the rack to the next operator. A very substantial amount of time was lost by each operator both in transferring successive lots of shoes to the next operator, and in waiting for shoes from preceding operators. The slowest operation served to hold back all other operations in point of time. The incomplete shoes were, of course, on lasts, and the number of lasts required became excessive by reason of the conditions just mentioned.

A rack containing a large number of pairs of shoes reduces the time spent in pushing" racks; but it increases the quantity of shoe material in process and the quantity of lasts required. Moreover, with a rack holding 'l2 pairs, the operator must hold up operations on '711/2 pairs while working on one shoe. The problem is not solved by diminishing the capacity of the racks because about on the factory iioor is increased.

In my Patent 2,114,486, I disclosed means and a method for increasing the ease, speed and economy of shoe, manufacture. The means comprised an elongated'chain conveyor carrying pins on which the lasts could be placed. The various machines and operations were correlated with each other along or near the path of the elongated conveyor. The conveyor moved slowly enough so that eachv workman could perform his vparticular operation on a shoe as it reached him, removfound to be the most ing they shoe and its last from the pin on the conveyor as that might be required. But the conveyor not only supplied each workman with shoes on lasts, but also delivered his product. to the next workman, thus saving his time. Also, by reason of the correlation, the number of lasts required was very greatly cut down.

The aforesaid patent among its teachings includes a statement of an exemplary arrangement of operators and operationsv in the making of shoes in a certain way. This sequence of operations may be followed with the means of the present invention, but is regarded by me as exemplary only and not as limiting.

Objects of the present invention include the` provision of improvements in means for handling and conveying shoes in such manner as both to correlate and facilitate operations thereon.

It is an objectof this invention to simplify and lower both the initial cost and the maintenance cost of conveying and correlating equipment.

It is an object of this invention to provide a new means for handling shoes on lasts for facilitating and improving operations thereon.

It is an object of this invention to provide an improved and semi-automatic means for the return of handling equipment and lasts.

It is an object of this invention to provide greater flexibility in the handling of shoes through a series of correlated operations.

It is an objectof this invention to provide drying means, the operation of which does not involve the waste of time in a correlated series of operations.

These and other objects of my invention which will be set forth hereinafter or will be apparent to one skilled in the art upon reading these speci# cations, I accomplish by that construction and arrangement of parts and in that procedure, of

,which I shall now describe an exemplary embodiment. Reference is made to the drawings wherein:

Figure 1 is an elevational view with parts in section of conveying and drying apparatus constructed in accordance with my invention.

Figure 2 is a partial sectional view taken through the conveying apparatus of Figure 1.

Figure 3 is an end elevation of the drying equipment with the conveyor partially shown in section. l

Figure 4 is an isometric view-of one of my pans. Generally, in the practice of my invention, I provide an dependent upon the available factory space and the number of operations), along which the sevelongated conveyor (the length being along on the conveyor, and they are designed tov hold units of shoes for convenient operation. The

pans and conveyor are so designed that rst, the

conveyor is under the control of any operator located along its length. Second, any pan can bec stopped and held stationary on the conveyor in spite of the continued movement of the conveyor and of preceding pans. Third, any pan can be bodily removed from the conveyor at any time or replaced thereon. Some of the operations are of such character that they may be performed 'pon the lasts while the lasts are on the pans andwhile the pans are cn the conveyor; and the structure of the conveyor is such as to withstand the necessary pressure of such operations, including hand tacking. But for such operations, the movement of the lasts may be arrested as aforesaid. Where a particular operation requires the removal of a last from the conveyor and its transfer, for example, to an adjacent machine, this is facilitated by the removal of the pans which contain chosen groups of lasts appropriate for the purpose.

Where a particular hand or machine operation requires longer time than'others in the correlation, it is merely necessary to multiply the number of machines or operators to equalize the eective speed of the operation with others. .The pans hold relatively few lasts and are relatively light in weight so that they may easily be handled by the operators.

A drier, as hereinafter described, may be located intermediate the length of the conveyor. The pans are transferred to carriers in the drier and then re-transferred to the conveyor` after they have passed automatically through a prearranged drying cycle. The drying operation does not, therefore, hold up other operations.

At the exit end of the conveyor, the finished shoes are removed from the lasts and the pans and lasts are returned by conveying means to the entering end of the conveyor where they may be immediately reused in operations in the same manufacturing cycle.

Referring to Figure 1, I have shown mounted above a floor i a long horizontal conveyor, a side rail of which is indicated at 2. This conveyor is supported above the iioor by supports or legs, generally marked 3. As indicated, the conveyor will be of a length appropriate to the available oor space and to the number of shoe manufacturing operations to be correlated along its length.' The main conveyor comprises a horizontal series of aligned rollers 4 mounted between` suitable side rails'. These rollers are driven.- A convenient way of accomplishing this is through the use of an endless belt 5, passing over pulleys 6 and 1 at the two ends of the frame. In its upper flight, the belt underlies the rollers 4 and is supported at intervals by other rollers, 8, so spaced, as shown, as to deect the belt slightly upwardly between adjacent rollers 4 to assist in maintaining the belt in contact with the rollers 4. The under or return flight of the belt will `be supported as may be required by rolls 9 at the positions of the legs 3, or by rolls mounted in depending brackets Iii fastened to the main rails 2 between the supports. Ay belt tightening arrangement, not shown, is preferably employed and may be mounted to move the bearings of the pulley4 1 on the bracket-like sup- 4 ports which I have shown, The shaft of the pulley 6 is extendedv beyond its bearings and is' provided with a sprocket connectlble to the sprocket I2 of a gear reducer I3. Th1s,in turn,

' mounted by means of roller is connected with a source Vof power such as an electric motor, not shown, preferably through a speed change means or variable drive so that the speed of the conveyor can be accurately made to correspond with the time required for the various shoe-making operations.

Beneath the main conveyor, I have illustrated rail means I4 supporting the rolls I5 of a roller conveyor located aslant so as to havea conveying function determined by gravity.

This conveyor structure may take a variety of forms. One way of making it is shown in Figure 2 where the legs `3 are shown supporting the rails I4 between which are mounted the rolls I5 of the gravity conveyor. An upright I6 is attached to the right-hand one of the angle iron rails I4 and, in turn, supports an inverted angle member I1. An upright I8 is attached to thc other rail I4 but is bent so as to extend outwardly and then inwardly again to give clearance at onel side of the gravity conveyor I4-I5 for the extending toe portions of lasts mounted upon pans. A portion I8a of the upright I8 parallels the depending leg of the angle member I1, and between these two parts, I mount both a roller I9 for the return or underight of the belt 5 and a roller 8, the Purpose of which has already been set forth. The upper end of the member I8 is bent over outwardly, as at I8b, to support the horizontal leg of one of themain conveyor rails 2, while the other ofthe main conveyor rails 2 is mounted as shown on the upper horizontal leg of the 'angle member I1. The roller 4 is mounted between the rails 2.

Since some operations may be performed on the shoes while they are supported by the conveyor, the rollers 4 should be satisfactorily sturdy. A variety of constructions is possible. An illus- .trated example includes a central shaft 2B mounted in and extending between the rails 2. The body of the roll 4 is a hollow metallic cylinder, as indicated at 4a; and at its ends it is bearings 2| upon the shaft 20'. A collar 22 is mounted on the shaft .at each end between the roller bearings and the rails. All illustrated rollers may, if desired, have the same construction.

The rails I4 extend somewhat above the upper surface of the rolls I5, while the rails 2 similarly extend above the surface of the rolls 4. The

" rails, therefore, can serve additionally as guides for the pan members which carry assemblies of lasts and shoes. These pans are sheet metal members, one form of which is shown in Figure 2. A base vor bottom for riding upon the rolls 4 is shown at 23v and 23a. At the side edges of the structure, the metal is bent up, as at 24, and the upper edges of the bent-up portions may be reinforced and strengthened by being turned over, as illustrated. In this form of pan. the

metal intermediate its width is bent upwardly, as at 25 and 26, and across aslant, as at 21, to produce-al-longitudinal upstanding ridge or corrugation, the top surface of which is disposed at an angle to the horizontal. A series of pins, 28, is mounted to project upwardly from the top surface of the ridge and are suitably fastened thereto. This may be done in a variety of ways, as'by riveting or the like; but a convenient mode of attachment comprises the use of headed pins and the vwelding of the head to-the underside may be provided on the porti-on 21 as are required to hold the lasts of a desired work group of shoes. I have shown in Figure 4 a pan having eight pins to accept eight lasts; but it will be understood vthat fewer or more may be employed. It is important, however, that the pan be so constructed that it may be lifted bodily from the conveyor, together with its shoes and lasts for the transfer of the work to operations which cannot be performed directly upon the conveyor. The pansl therefore, should not be so large or so heavy as to be inconvenient for one operator to lift and carry. Within this limitation, the number of lasts per pan can be worked out in accordance with the requirements of any given manufacturing operation.

Considerable modification may be made in the construction of the pans, and I have shown yet another construction at `3l) in Figure 3.` The lasts themselves have been indicated in Figures 2 and 3 at 3l, and the purpose of the inclination of the top surface 21 ofthe ridge member of the pans is to present the lasts to the operators in a convenient position for the various operations. The distance between the upturned side portions 24 of the pans is, of course, somewhat less than the distance between Athe side rails 2 of the upper conveyor or the side rails I4 of the lower conveyor; and these side rails serve as guides to keep the pans on the conveyor. Y Any pan, can, however, be brought to rest by any operator manually or otherwise. The rolls 4 will continue to turn beneath it but without too great friction.

VZin Figures 1 and 3, I have shown drying means comprising a vertical housing 32 and an overhead horizontal housing 33 connected with it.

A pair of chains 34 and 35, one at either side of the housing, pass over sprockets 36 on a shaft 31 at the lower end of the vertical casing portion. 'I'he shaft 31 extends through the housing, and is provided with a sprocket 38 which may be connected by a chain 33 to the sprocket 40 of a gear reducer or the like, 4|, which in turn is powered by a motor or other prime mover. At the top of the vertical housing portion 32, as shown in Figure 3, the chains pass over sprockets 42 and 43, passing horizontally through portions of the horizontal housing 33 and returning in an upper flight over sprockets 44 and 45 near the ends of the horizontal casing. The horizontal portions of the casing may be suspended from above by rods 46, Passing between the chains 34 and 35 and--attached to them at intervals are shafts 41, from which are suspended hanger-like members 48 of triangular shape. The lower ends of these members are bent horizontally inwardly, as at 43, and are designed to serve as supports for the pans. A pan is shown in place on these supports at 50 in Figure l.

The chains are guided in their several flights by channel-shaped rail members, shown at 5l and 52 in Figure 3. The hangers 48 are free to rotate on the shaft 41 under the influence of gravity, as will be clear. The front portion of the vertical housing 32 is open, as shown in Figure 1, for a convenient height above the main conveyor. An inspection window, 53, may also be provided if desired. An air heating or conditioning unit, which may include means for solvent recovery, is indicated diagrammatically at 54, connected by conduits and 56 to the casing of the drier.

VWhen a pan containing shoes at a stage of manufacture requiring drying reaches an operator stationed at the drier, he lifts the pan from the conveyor and places it on the hangers 48-49 of the drying conveyor. It then proceeds automatically through the various paths traversed by chains within the casing of the drier, iinally returning to the point at which it was placed thereon. The operator can then return it to the conveyor. It will be understood that in normal operations, all of the l in the drier, will be filled withpans holding shoes or lasts. The drying cyclemay consume whatever time is required for proper drying; but this is not time taken from the general manufacturing operation because pans of driedfshoes may be returned to the conveyor as rapidly as pans of shoes requiring drying are removed therefrom by the operator.

In the use of my apparatus, itis contemplated that a series of operations will be performed` on shoes which may include al1 of the operations to be performed thereon as respects lasting,'drying and similar operations. The last travel with the pans, but can individually be removed therefrom if necessary. The pans themselves contain groups of lasts and shoesof a convenient size for operations eitheron the conveyor or on machines or benches adjacent thereto, so that as respects the conveyor at least, it is neither necessary to remove and handle individual lasts and shoes. which is time-consuming, or to handle large groups of shoes, which is likely to delay a manufacturing program. Any pan may be stopped for individual operations at any position on the conveyor or removed therefrom. Furthermore.

the conveyor itself is designed to be under the control at all times of all operators, or at least of all key operators in the program. This is accomplished by providing switches, one of which is indicated at' 51 in Figure 3, at all key stations. These switches may be connected in series and to the electric motor driving the conveyor so that all switches must be closed before the conveyor can move. Any operator is thus in a position to stop the movement ofthe conveyor at any time; and the conveyor cannot be started so long as any operator has his switch open. At the end of the conveyor, the shoes may be removed from the lasts by an operator stationed there who then will return the pans and lasts to the starting position by placing them upon the gravity conveyor I4-I5.

Modifications may be made in my invention without departing from the spirit of it.

, Having thus described my` invention, what I claim as new and desire to secure by Letters Patent is;

1. In a device for the purpose described, an elongated rectangular supporting member with a central, longitudinal raised portion having 'a plurality of upstanding spaced pins on said raised portion to accept a plurality of'shoe lasts, side edge portions of said supporting member extending sumciently beyond said central raised portion to provide freedom from a tendency to tilt.

2. A member for holdinga work unit of shoe hangers, or many of them lasts, said member being formed of sheet metal bent to provide a base portion, upstanding side ridges. and an upstanding intermediate ridge, said last mentioned ridge bearing a plurality of pins for accepting shoe lasts.

3. A member for holding a work unit of shoe lasts, said member being formed of sheet metal normal to the plane of said upper surface.

4. A member for `holding a work unit of shoe lasts, said member being formed of sheet metal bent to provide a base portion, upstanding side ridges, and an upstanding intermediate ridge,

donev thereon without stopping said conveyor, said conveyor having side guide means and being of a width substantially the same as the width of said shoe last supporting means.

7. In means for the purpose described, an elongated conveyor with respect to which a plurality of shoe fabricating operations may be located and correlated, and a series of shoe last supporting members transportable on said` conveyor, each of said members having an elongated base with a central longitudinal raised portion and a plurality of upstanding pins on said raised portion to accept a plurality of shoe lasts, side edge portions of said base extendingsuiiiciently beyond said central raised portion to provide freedom from a tendency to tilt, said shoe last supporting members being of a shape and size to hold groups said last mentioned ridge bearing a plurality of 'pins for accepting shoe lasts, said upstanding ridge having an upper surface aslant to the plane of said base, said pins being positioned substantially normal tothe plane of said upper surface, said member being of a size and weight, together with lasts and shoes, for lifting and transportation by a single operator.

5. In means for the purpose described, an elongated conveyor with respect to which a plurality of shoe fabricating operations may be located and correlated, and a series of shoe last supporting members transportable on said conveyor, each of said members having an elongated base with a central longitudinal raised portion and a plurality of upstanding pins on said raised portion to accepta plurality of shoe lasts, side edge portions of said base extending suiciently beyond said central raised portion to provide freedom from a tendency to tilt, said shoe last supporting 'members being of a shape and size to hold groups of lasts constituting convenient work units and being readily removable from said conveyor by a single operator, said conveyor having driven propulsion means including means capable of resisting the downward thrust and impact of work performed on shoe elements on said lasts While on s aid shoe last supporting means, and said propulsion elements having frictional driving contact only with'said shoe last supporting meansl whereby said shoe last supporting means may be stopped on said conveyor to permit work to be done thereon without stopping said conveyor.

6. In means for the purpose described, an elongated conveyor with respect to which a plurality of shoe fabricating operations may be located and correlated, and a series of shoe last supporting members transportable on said conveyor, each of said members having an elongated base with a central longitudinal raised portion and a plurality of upstanding pins on said raised portion to accept a plurality of shoe lasts, side edge portions -of jsaid base extending sufciently beyond 'said central raised portion to provide freedom from a tendency to tilt, said shoe last supporting members being of a shape and size to hold groups `oi lasts constituting convenient work units and ,being readily removable from said conveyor by a. single operator, said conveyor having driven propulsion means including means capable of yrej sisting the downward thrust and impact of work performed on shoe elements on said lasts while on said shoe last supporting means, and said propulsion elements having frictional driving contact only with said` shoe last supporting means whereby said shoe last supporting means may be "stopped on said conveyor to permit'work to be of lasts constitutingI convenient work units and being readily removable from said conveyorby a single operator, said conveyor having driven provby said shoe last supporting means may be l'stopped on said conveyor to permit work to be done thereon without stopping said conveyor, said conveyor having side guide means and being of a. width substantially the same as the width of said shoe last supporting means, there being along the length of said conveyor a plurality of control means any one of which is eii'ective to stop said conveyor.

8. In means for the purpose described, an elongated conveyor with respect to winch a plurality of shoe fabricating operations may be located and correlated,` and a series of shoe last supporting members transportable on said conveyor, each of said members having an elongated base with a central longitudinal raised portion and a plurality of upstanding pins on said raised portion to accept a plurality of shoe lasts, side edge portions of said base extending suiiiciently beyond said central raised portion to provide freedom' from a tendency to tilt, said shoe last supporting members being of a shape and size to hold groups of lasts constituting convenient work units and being readily removable fromsaidconveyor by a single operator, said conveyor having driven propulsion means including means capable of resisting the downward thrust and impact of work performed on shoe elements on said lasts while on said shoe last supporting means, and said propulsion elements having frictional driving contact only with said shoe last' supporting means whereby said shoe last supporting means may be stopped on said conveyor to permit work to be done thereonwithout stopping said conveyor, said conveyor Ihaving side guide means and being of a width ysubstantially the same as the width of said shoelast supporting means, `there beingy along the length of said conveyor a plurality .of control means any one of which is effective to stop said conveyor, said conveyor comprising as the driven `propulsion means a horizontal series of vsupporting rotatable rollers, an endless belt having an upper. flight contacting the under sides of said rollers, and means for maintaining said belt in contact with said rollers, there being power means effective to move said belt. l y

9. In means for the vpurpose described, an elongated conveyor with respect to which a p1u- `Ilma-11S,

operations maybe lolast supporting members transportable on said conveyor, each of said members having an elongated base with a central longitudinal raised portion and a plurality of upstanding pins on said raised portion to accept a plurality of shoe lasts, side edge portions of said base extending sufficiently beyond said central raised portion to provide freedom from a tendency\to tilt, said shoe last supporting members being of a shape and size to hold groups of lasts constituting convenient work units and being readily removable from said conveyor by a single operator, said conveyor having driven propulsion means including means capable of resisting the downward thrust and impact of work performed on shoe elements on said lasts while on said shoe last supporting means, and said propulsion elements having frictional driving contact only with said shoe last supporting means whereby said shoe last supporting means may be stopped on said conveyor to permit work to be done thereon without stopping said conveyor, said conveyor having side guide means and being of a width substantially the same as the width of said shoe last sup-4 said rollers, there being power means effective to move said belt, and a second conveyor beneath said first mentioned conveyor and adapted to return said shoe last supporting members in the opposite direction, said last mentioned conveyor being a gravity conveyor aslant tothe horizontal and having a series of supporting rolls.

11. In means for the purpose described, an elongated conveyor with respect to which a plurality of shoe fabricating operations may be located and correlated, and a series of shoe last supporting members transportable on said conl veyor, each of said members having an elongated base with a central longitudinal raised portioni and a plurality of upstanding pins on said raised portiontoaccept a plurality of shoe lasts, side edge portions of said base extending sufciently beyond 'said central raised portion to provide freedom from` a tendency to tilt, said shoe last supporting members being of -a shape and size to hold groups of lasts constituting convenient work units and being readily removable from said con veyor by a single operator, said conveyor having driven propulsion means including means capable of resisting the downward thrust and impact of i work performed `on shoe elements on said lasts porting means, there being along the length of said conveyor a plurality of control means any one of which is eiective to stop said conveyor, said conveyor comprising as the driven propulsion means a horizontal series of supporting rotatable rollers, an endlessbelt having an upper flight contacting the under sides of said rollers, and means for maintaining said belt in contact with said rollers, there being power means effective to move said belt, and a second conveyor beneath said first mentioned conveyor and adapted to return said shoe last supporting members in the opposite direction.

10. In means for the purpose described, an elongated conveyor with respect to which a plurality of shoe fabricating operations may be located and correlated, and a series of shoe last y an endless belt having an supporting members transportable on said conveyor, each of said members having an elongated base with a central longitudinal raised portion and a plurality of upstanding pins on said raised portion to accept a plurality of shoe lasts, side edge portions of said base extending sufficiently Abeyond said central raised portion to provide freedom from a tendency to tilt, said shoe last supporting members being of a shape and size to hold groups of lasts constituting convenient work units and being readily removable from said conveyor by a single operator, said conveyor having driven propulsion means including means capable of resisting the downward thrust and impact of work performed on shoe elements on said lasts while on said shoe last supporting and said propulsion elements having frictional driving contact only with said shoe last supporting means whereby said shoe last supporting means may be stopped on said conveyor 4 while on said shoe last supporting means, and said propulsion elements having frictional driving contact only with said shoe last supporting means whereby said shoe last supporting means may be stopped on said conveyor to permit work to be done thereon without stopping said conveyor, said conveyor having side guide means and being of a width substantially the same as the width of said shoe last supporting means,

there being along the length of said conveyor a plurality of control means any one of which is effective to stop said conveyor, said conveyor comprising as the driven propulsion means a horizontal series of supporting rotatable rollers,

upper flight contacting the under sides of said rollers, and means for maintaining said belt in contact with said rollers, there being power means effective to move said belt, and a second conveyor beneath said first mentioned conveyor and adapted to return said shoe last supporting members in the opposite direction, said last mentioned conveyor being a gravity conveyor aslant to the horizontal and having a series of supporting rolls, and a drying means located intermediate the length of said conveyor, and comprising a casing, supporting means for accepting said shoe last supporting members, and means for moving the saidI supporting members continuously within said casing in a predetermined path of travel.

12. In a conveyor structure spaced rails mounted upon supports, a plurality of rollers journaled between said rails in a horizontal series so that the rails extend above the upper surfaces of said rollers to form guides, an endless belt passing beneath said rollers and contacting them in its upper flight, roller means for keeping said belt in contact with said rst mentioned rollers, roller means for supporting the lower flight of said belt, another pair of rails located on said supports beneath said first mentioned rails, and a series of rollers mounted between said last mentioned rails, said last mentioned rails disposed aslant to the horizontal between said supports so as to constitute said last mentioned series of rolls a gravity conveyor, in combination with a series of elongated metal pans dimensioned widthwise to lie between said rails on said first and last mentioned l1 bearing pins for the acceptance of shoe lasts, said pans being movable in one direction by said rst mentioned rolls when driven by said beit and returnable in the other direction by said gravity conveyor, said rst mentioned rolls serving to support said pans to permit work to be done in shoe elements supported by said lasts.

BRUNO T. GIALDINI.

file of this patent: 4

UNITED STATES PATENTS Number Name Date 723,825 Butter-neld Mar.31, 1903 Henry, Jr. Feb. 9, 1904 Number 12 Name Date' Crossley Aug. 13, 1907 Mashek Oct. 19, 1915 Locke Apr. 12, 1921 Mills et -al May 23, 1923 York Jan. 18, 1927 Glidden Feb. 26, 1929 Young Dec. 17, 1929 Walter et al. 1 Oct. 18, 1932 Waiter etal. Apr. 11, 1933 Stokes ...j Sept. 22, 1936 Joyce June 5, 1945 FOREIGN PATENTS Country Date Italy Jan. 15, 1937

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