US2741880A

US2741880A - Grinder or the like

Info

Publication number: US2741880A
Application number: US257024A
Authority: US
Inventors: John J Falls
Original assignee: Standard Electrical Tool Co
Current assignee: Standard Electrical Tool Co
Priority date: 1950-01-13
Filing date: 1951-11-19
Publication date: 1956-04-17
Anticipated expiration: 1973-04-17

Description

April 17, 1956 -J. J. FALLS 2,741,880

- GRINDER 0R 'rx-1E LIKE:

Original Filed Jan. 13, 1950 4 Sheets-Sheet l INVENTOR,

April 17, 1956 J. J. FALLS GRINDER 0R THE LIKE original Filed Jan. 1s, 195o 4 Sheets-Sheet 2 @/0/71? d f//s INVENTOR,

April 17, 1956 J. J. FALLS GRINDER OR THS LIK 4 Sheets-Sheet 5 Original Filed Jan. `13, 1950 I l l 1 cfa/m df// INVENTOR, Waff @riad United States Patent O GRINDEn on THE LIKE `John alls', Cincinnati, Chio, assigner to The vStalndard Electrical Tool Company, Cincinnati, hio, 'a corporation of Ohio 4(jriginafl"application January 1.3, 195i), Serial No. 138,443,

Divided and `this application November 19, 1951, Se- `l'il N0. 257,024

2 Claims. (Cl. l-ltl9) This application is a division of my pending `applicationSerial Nadi-38,448, filed January 13, 1950, and entitled Grindrerilor the Like. j The `present invention relates to aigrinder or similar machine for the shaping of high'ispeed steel tools or other objects.

A An object of the invention `is to provide ainovel construction in grinders, whereby to enhance the convenience of usage, of4 adjustment; andiof maintenance.

Another object is to provide means in association with `a grinding machine, for firmly supporting the object `undergoing` grindingwith greater than usual solidity, thereby to improve thelquality of the work and the speed with which it` may be performed.

`Another object of the invention is to provide improvements in agrinding machine wherebyto achieve maximum rigidity, durability, and simplicity of the machine, with attendant advantages of vibrationless operation and in* creased safety for th'e benefit of the operator.

j A further object is the production of a bcdily `replaceable drive unit for the grinding wheel, having `a novel adjustment means incorporated therein, and adapted for independentlusage in different types of machines.

Other objects are: to ensure maximum operator visibility and comfort, savings in grinding time and floor fs'pace, ease of adjustment, andof replacement ot` wearing partsoprdvi'sion for w'et or dry grinding, convenient access tfall-partsirequiring periodic or occassional attention, `and eiective control adjustment of coolantflw.

The foregoing and other objects are attained by the means described `herein and illustrated upn the accompanying drawings, in which:

Fig. 1 is `a perspective View of the new grinder orfthe like, embodying the improvements of the present inven- Ltion.

Fig. 2 is a side elevation of the upper hal'onff'tlieima- "chineiillilsti'atedlbyFig;l. l "Fig 3 is a `parstia'etivo view 'of a 'coolant sp'la'sligdard.

AIilg: f4 is a ifroiitfelevational view of the niaehid-,parts the 4il'iiit of Fig; 5, said grinder being of a dilrareot tvpje than that of Eig. l. p

Fig. A8-is abide elevational ryieWfoif third type of irlcludi'rga pair of the Fig;` S'units. 4

ral, the grinder as illustrated pn Figsnl to V iii'clude'sy a suitable stand or pedesltalltZ` idly mounted a trough member 13 adapted to `Iii gene' @eine 'collect g` A* digs 'aad/oi eoolaot gravitatiiig noialtri-e grinding 'wheels r4 and is; and forwardly of tha `*gri-nd- ;iilgiwlleel are' arranged the worktabls or tool supports 116 and 17;'which,niilik' thetabls connri'only used tipo'n grinding apparatus, are Xed against bodily movement or adjustment toward aildfroin the working `faces of Ythe wheels `14 and IS. The wheels themselves` are bodily shiftable or adjustable toward and. from lthe tables, whether thewheels are in motion or at rest. This bbdily adjustmentof the grinding wheels is accomplished withA out disalignment ofnth'e driving means therefor, as will be explained in detail hereinafter. Y

It may here benoted that `the grinding wheels employed on the present machine are of the cup type,(see Fig. 5), meaning that the abrasive substance of the wheel is intheiform of a short cylinderor ringlixed axially upon a base disc 18, which disc in turn may be demountably attached to a driving disc `19 forming partlofthe driving unit 23a` of Fig. 51 ScrewsY 20 having socket heads are suggested 'asconvenient means `for detachably mounting the grinding wheel -upon thedisc 19 of the driving unit. The abrasive ring may be attached toitsV disc 1'8bfy cernenting, vulcanizing orv other means immaterial to the present invention. The parte consisting of the abrasive 'ring and its permanently attached disc 18, may properlyl be termed a grinding unit, as it `is bodily replaceable "upon the drivedisc 19 whenever thering wears down tozan appreciable'eittent inthe direction of the disc 18. The working orWearing `surface of thefgrinding' wheell is indicated at 2-1,`and=isgenerally noinl to the axis of rotation.

`With further reference to Fig. 5, it should be remembered that the grinding Whe'eland the driving disc 19 are `bodily shiftable axially of the driving unit 23`by manipulating fa handle 22, to'adjust theworking face of the wheel toward and from the work table. This adjustmentis obtained'ehiey Byre'ason 'o frthe fact tliaivtha'inain sliart or the driving unit is telescopcallyextensible, withoiltairially shifting the drive pulley 24. It is for this reason that tile worlt 'table Yremains ytired' and 'rigid throiighout the grinding operation, 'to enhance `tl-ia accuracy andspaed orftli'e grinding operation. 1

According-toFigl; the working facesof bbthgrihdihg wheels fa'c'e the front f'tlie machine, where theope'rt'r isfstaticin''cl, so that tlieopfe'rat'or may grindat'ool or other objectupon either of the wheels 14V or 175, without walking partly around the machine. That is, the operator need only take a shor'tlsi'desltep to the right lor `left in order to use either grinding v/heel; one of whicliinay beV coarse grinder `andthe other a "iiiiish grinder. Moreover', this machine maybe placed with its back against a wall, with out inconvenience to operator, and with a savingtof valilableoor space`abtittherriachineY All controls and adjust'rn' tits `are 'easilyfaccess'ible from lthe operators sta- 'tioa att o the aristas. l

:s l i ingnictorfo'rthe machine is` at Zlib, while 2S ildlcte's'a self-priming pump for liquid cocant, the motor by a belt or chain dotlljle ley'2`7bh the motor "shaft drives a pair of belts 28-'5-28, Botti of wliihpmav bettaiited over die .doable pilllevs 244244 of the drive units totV rotate both grinding whjeels iii foininn direction., Tile iiiotor 225.0 is reversible. and may elstr'ted and stopped by means of any suitable typefof Velectricswitch controlledbya handle or switch actuator 29 located preferably between the lt'vvogrinding wheels. The wheels, of course, may be driven by a-single belt 28 or bylmeansof achainand-sprocketarrangement, irdesired. 'lhepurnp isarranged to drawlllqnidcoolant from a reservoir 30, and to force thecoolant` upwardly thrbughpipei which feeds theseveral delivery nozzles 32 `-located at the grinding faces of wheels identi The coolant7 after striking the faces of the wheels, graviA tates 4into the vhollow trough member 1s add 'retraits 'in the 'reservoir 30 by way df "pipe 33; Before entering the `pipe 331, the coolant passes `through a strainer 'nos sa .(Figz 2) located within die trough member;

Each of the coolant delivery nozzles 32 (Fig. 2), is

mounted in upright position upon a hinged wheel-hood 35, which may be swung upwardly about a hinge such as 36 to expose the grinding Wheel. The hood 35 carries also a selector valve 37 of any approved type, operative by means of a handle 3S to supply coolant to either nozzle of a pair associated with each grinding wheel. A tiexibic hose 39 feeds coolant from the pump line to the valve 37. This valve may preferably include a shutnoit, to terminate coolant flow to both nozzles supplied thereby.

The coolant delivery nozzle in each instance may be adjustable vertically to dispose its delivery port at diiferent elevations above the work table and any tool or other object supported thereon for grinding. One representative form of adiusting means is illustrated upon Fig. 2 by way of example, and consists of a bored block 41 slidably receptive of the pipe-like nozzle element to per mit sliding of the latter upon a tube d2 leading from the valve. The nozzle may be fixed in adjusted positions by means of a thumb-screw 43 screw-threaded into the block as shown, the block being fixed to the hood 35. A hood latch is indicated at 44.

When the hood 35 is swung upwardly about its hinge 36, through an arc approximating 90 degrees, the grinding wheel is fully exposed for application of a wrench to the several screws 2i) which secure the wheel to the driving disc 19. By removing said screws, the worn or used grinding wheel may simply be lifted bodily from its normal position adjacent the work table, and, without any interference from the nozzle 32 or other parts of the machine, replaced by a new wheel. The hood may then be lowered and re-fastened at screw 44.

To avoid splashing of coolant beyond the sides of the hood, there is provided a pair of splash guards for each grinding wheel. These splash guards, detailed at 45, Fig. 3, may depend vertically from horizontal rods (Fig. 2), and lie close to the grinding wheel periphery, to intercept liquid coolant thrown outwardly by centrifugal action as the wheel rotates. The rods 46 may be anchored at 47 in the front frame panel 248 of the machine pedestal, and are independent of movements of the hood 35. Referring to Fig. 3, the splash guard consists of a sheet, preferably metal, having opposite side edges turned approximately at right angles to provide

opposed flanges

48 and 49, developed at their upper ends to form perforated ears 50 receptive of the rod 46. The guard is slidable upon the rod longitudinally thereof, to an operative position at which the inwardly offset lower portion 480 of flange 48 lies substantially in or slightly behind the plane of the working face of the grinding wheel, to avoid interference with manipulation of a work piece or tool undergoing grinding. The upper flange portion 48, being offset outwardly beyond portion 480, will naturally extend forwardly of the working face of the wheel, and at an elevation such as to likewise avoid such interference. Coolant striking the guard anywhere above the curve or offset 481, will be thereby directed down toward the end 52, which depends into trough 13. To prevent coolant from running down the outer faces ofthe splash guards, baflles fixed to the hoods may overlie the upper ends of the splash guards, as at 450 (Fig. 4). Depending upon the direction of rotation of the grinding wheel, one or the other of a pair of splash guards will be adjusted to the wheel as above explained. A finger piece or knob 51 facilitates adjustment of the splash guard along its support rod 46.

Attention is now directed to the work tables 16 and 17, which are identical in construction, wherefore a description of one will suice for the other also. Referring to Fig. 2, in which the table is shown horizontal, rather than tilted as in Fig. l, the character 53 indicates a rock stud shaft which supports the table in an infinite number of angular positions between the limits of the graduations marked upon the indicator plate 54. The pointer 55 is adapted to indicate in degrees of inclination, the slope of the upper face of the work table. Accordingly, the

pointer and the shaft should move with the table when tilted about the shaft axis.

The table may be in the form of a metal casting having opposite ends .5d-57, a forward depending apron 58, an open back portion 59 to admit the grinding wheel, and au upper plane surface titl to which are secured the accurately machined and

hardened wear plates

61 and 62. These wear plates are replaceable when worn or damaged, and may be held to the table top by means of screws or other fasteners 63. The plates preferably are spaced apart as indicated at dal, to accommodate a protractor tool guide or holder, if desired. The wear plate 61 is cut away to provide a straight edge 65 forwardly of the grinding Wheel working face, and from said straight edge may project an adjustable slide 66 carrying a safety lip 67 to prevent tools or other objects dropping into the central recess of the grinding wheel. ln practice, the lip extends into the wheel recess. As heretofore pointed out, the grinding wheel is adjustable bodily toward and from the table edge 65, and no provision is made for shifting the table toward and from the working face of the grinding wheel.

Means are provided for tilting the work table and locking it at predetermined degrees of inclination relative to the plane of the wheel face. As previously pointed out, the table may tilt with the studs 53 supported in bearings 68-69 at opposite ends of the table, the bearings being carried by the trough member 13 or any other stationary part of the machine available as a bearing support, such as bracket 7G. To hold the table in its various positions of inclination, opposite ends of the table may be provided with arcuate slotted arms 71 pivoted to the table ends at 72, and reaching down into the trough member to engage a clamping shaft 73 that passes through the slots of the arcuate arms. The shaft 73 is supported at its inner headed end 74 (Fig. 4) by a bracket 75 fixed within the trough member, whereas the outer end of the shaft is threaded as at 76 and receives support from a bored boss 77 formed on an end wall of the trough member. A hand nut 78 serves as the means to draw the shaft toward the boss, with slight llexation of bracket 75 resulting, to clamp the arcuate arms 71-71 against the ends of a loose sleeve 79 which surrounds the shaft between said arms. By means of this arrangement or any one of many possible variations thereof, the tiltable table may be set and held at predetermined degrees of inclination, in accordance with the requirements of the grinding operation.

It may here be noted that the rear wall of the trough member, at 80 (Fig. 2), has an opening behind each grinding wheel leading to a collecting chamber 81 provided with an exhaust port 82 in the side of the pedestal, to which may be attached a suction pipe for carrying away dust and grit produced when the machine is used in dry grinding operations.

The grinding wheel driving unit of Fig. 5, indicated generally at 23 throughout the drawings, has many different applications of usage in the grinding art, and possibly in other `lields where a rotarycutter or trimmer may best be advanced to the work and retracted therefrom, instead of moving the work bodily relative to the cutter or trimmer. Two typical applications are illustrated by Figs. 7 and 8, these having been selected from a number of current applications presently undergoing development. The devices of Figs. 7 and 8 will be described following the detailed explanation of Fig. 5, below.

In Fig. 5, the cylindrically bored housing 83 is provided with a mounting base 84, and opposite the base is formed a longitudinally extending slot or guideway 85 in which may travel a nut 86. The nut in traversing the guideway 85, carries with it a cylindrical ram 87 to which the nut is secured by fasteners 88, or otherwise. The width of the nut approximates the width of the guideway, so that the ram may reciprocate within the housing bore 89, but may not rotate therein. At the right or :gymnase forward end eine ram, there is fmduntedxettlyyasjtgy means of screws 90,. an anti-friction bearing retainer 91. One or more anti-friction bearings 1,01 supportdliejr'eaucedend 93 of the main envi-.shaft 94er the unit `rhe hub 95 of disc 19 fits 'over the reduced eudfdf the 'shaft 'and is keyed thereto Yat 96, with albolt and washer 97-l- 98 serving to force and hold the `hub rmlyjag'ainst "the innerbearing race 492. The outer mahinedfsurfac'e of the hub '95 `r`u`ay be sealed again'stlefa'kage dfplubr'ican'lt from the bearings, by the annular packing ring"99 carried by member T91. A second lubricant retaining ring 100 may be carried by the ram, to providen'a'ssociation with the first ring, a lubricant retentive `clia'n'ib'er for .the bearings 101. Y y A The rear or left end ofthe cylindrically bored housing 83 has an 'annular partition Wall 102 formed therein, with a `groove providedto seat va lubricant retaining'ring 103. This .ring surrounds and seals against arrotary sleeve 104, which through the medium of one'or more Aelc'i'lgated keys 'or splines `1.05, has a driving connection with the main shaft 94. The spline ork'eyw'ayfor thj rey 10s is provided in the elongate redcedaiameterj end 106 of the shaft, and as Fig. 5 indicates, this end fithe shaft may extendbeyond the end 10'7A of the sleeve The driving pulley 24 is secured to the sleeve end 107 by one or more set-screws 108, and may also be keyed thereto in accordance witli comm'on practice.`

The rear end of the housing 83 is recessed "to receive the bearing 109 and the nut `110 which securesthe bearing to the annular shoulder 112 of the divsleve 104. The periphery of this shoulder maybe sealed by means `of the lubricant retaining ring 113 `carried by Lthe end `cap or plate 114 used in closing the bearing recess or lchamber 115.

flt will beunderstood from the above explanatiomthat fpulley 24 drives the sleeve 104 with a rotary motion only, the sleeve being incapable of any perceptible longitudinal movement. Through the medium of the key `or spline connection 105, the sleeve 104 drives .the mainshaft '94 Aand the grinding wheel 14 thereto attached. Now if the adjusting screw 116 be rotated for-thetpurposeof traversing the nut 86, and extending the ram 87 attached thereto, `the splined or keyed end 106 of themain shaft 94 `will bedrawn `to the right, along with the 'ram and `the grinding wheel. Regardless of the extent to whichithe `ram and grinding wheel are thereby projected by the action of the adjusting screw upon the nut 86, as limited by lthe length of slot 85, the driving connection between the pulley, the sleeve, and the shaft, is always maintained. It should be understood that the shaft is a single piece, from the drive pulley to the wheel disc 19. The shaft has no relative movement longitudinally of the ram 87.

Fig. shows the ram and the grinding wheel in fully retracted position, which is the same position shown in Fig. 2. To place the grinding wheel in normal operating position, the adjusting screw 116 would be operated by fro means of the handle 22 and the intermediate gearing 117,

to advance the nut 86 to the right. The nut carries with it the ram, the drive shaft, and the grinding wheel as previously explained. When the screw 116 has been rotated sufficiently to bring the working face of the grinding wheel within a short distance of the table edge 65, the machine is ready for operation. Of course, as the wheel wears away, readjustment of the unit by means of the adjusting handle 22 becomes necessary if the proper working relationship between the grinding wheel and the work table is to be maintained.

Referring to Figs. 5 and 6, it may be noted that the adjusting means can be designed for actuation in several ways. In accordance with the Fig. 5 disclosure, the unit housing has an extension 118 provided with a bore 119 in which is fitted a sleeve 120. The sleeve provides a vertical bearing for the actuating shaft 121 which rotates the miter gears for rotating the adjusting screw and traversing the nut 86. When an angular relationship bemanner.

weer the adjusting straw and the actuating banale is antennae, Ythe 'screw *may antennae 'a einer `eenaeeapnwith-the hernie as gesteery'rig. s. Answer passible variaties lessee massages-rating the-usa errrg. 5 with its-ease aaiedteaaupaghf sanne,

Fig. 8, in which case theoprating 'shaft will extend lit-this maclii'nytli table may be of the type illus- Ati-a'tedby Fig. l,-drinthalterhative, it may be reciprocabl'e on theway's-126transversly of the grinding wheel, either manually or automatically'. As shown, the table in'aylev actuated-mung the wysvbyrneans 'ofA a pneumatic or 'hydraulic cylinder-meter '127appli'cd in a customary Manual reciprotiun may be had by means of ah'ndle 128 'secured tu the table, or otherwise arranged to move the table by manipulating th'e handle. In the reciprocating table type of machine, the work piece may Besecured to the'tble in the usual way to engage the grinding wheel.

'The table bdfcarr-ying "the ways 12'6 may be tiltable abouta `stationary pivot r 'rock shaft 129 supported upon bracket mea-ns 130, and suitable clamping means maybe provided 'for maintaining the table at adjusted inclinations. A simple `coriviitioiial clamping means is `slro'wii by way of example, as an arcuate slotted arm 131 scui'able hymens of ahaiid nut 132,` substantially in accordance with -the disclosure at`71'-`72--73 f Fig. 2. innig. 7, drivingbeus 13s corresponding to those at ze f Figs. 2 and 4 transmit power from 4the motor (not shown) t the drive1 pulley 1346i unit '23. A coolant delivery nozzle is indicated "at 135.

"The device of Fig. S is a machine utilizing two of the drive 4units 23 arranged with the main shafts thereof iiiu axial alignment. `Each unitcarries a grinding wheel 136, and working faces of the wheels are disposed in closely spaced parallelism so that between them may be inserted 'a plate or strip to be ground and dressedjon opposite faces.y The arrangement `i`s 'suitable for grinding smooth a weld joining the` edges of two coplanar sheets cxrplates',l for `example., The space between the grinding Wheels 13644136 may be varied by simply `inanipulating one or both handles 22 of the" driving units 23. The unitsinaybe mounted upon' the parallel frame members 137 and '13801 iie iiacliiri'e', s'by bolts or other fasteners 139, and may be driven by one or more motors, the drawing suggesting by way of example the individual

electric motors

140 and 141, driving the upper and lower units by means of belts and pulleys 142, 143, and 144, or the equivalent. In this modication, indicates the unit adjusting screw, and 146 is the nut which travels along the screw to advance the ram and the grinding wheel, as was explained in the description of Fig. 5.

The machine of Fig. l is known as a twin wheel grinder, and in practice it will be furnished with grinding wheels of diiferent grades so that rough grinding and nish grinding may be performed on the same machine with great facility and unusual speed and accuracy. A single wheel machine is sometimes desired, and in that event the machine may be built upon a smaller pedestal or base, with omission of such parts as are not needed for single wheel operation. That is, the single wheel machine will require but one each of the grinding wheels, drive units, work tables, and coolant systems. A single drive belt 28 ordinarily will suice, also.

Referring to Fig. 1 of the drawings, the character 147 indicates a resilient tray conveniently accessible to the operator, and upon which may be placed tools, bones,

and other objects needed at the machine. The tray may be mounted atop the machine frame, preferably, between the grinding wheels, and will preferably consist of a slab or sheet of composition board material other than metal, upon which the tools vor other objects may be placed without injury to the sharpened or finished edges or faces thereof.

The forward panel 148 is made removable for ready access to the coolant system, the drive motor, and their adjustments (see Fig. 4). An examination of Fig. 4 clearly reveals the fact that any of the belts driven by the motor 240 may be quickly replaced when worn, without in any way dismantling the machine. The pump 25 is indicated conventionally for the reason that it may be any one of several known forms which produces a unidirectional flow of liquid irrespective of the direction of rotation of its driven shaft. Diaphragm types of pumps, for example, are in this category.

It is to be understood that various modications and changes in the structural details of the devices embodying the invention may be made, within the scope of the appended claims, Without departing from the spirit of the invention.

I claim:

1. A grinding machine including a grinding wheel, and an upright frame having a front wall, and comprising in combination therewith a stationary trough member extending across the front wall of the frame, said trough member having a bottom Wall, apertured end Walls and a front Wall, and an open top defined by upper edges of said walls, the trough member being lixed upon the frame in a substantially horizontal position, a work table having a working edge adjacent to the grinding wheel, and ncluding depending side walls and a depending front wall, means rockingly supporting the table upon the stationary trough member for movement from a horizontal position to inclined positions, said table in the horizontal position having the lower edges of its front and side walls disposed below the upper edges of the corresponding trough member walls, thereby to dispose corresponding walls of the table and the trough member in overlapping relationship, and table clamp means within the trough member concealed by said overlapping Walls, including an actuator extending to the exterior of the trough member through the aperture in the side Wall thereof.

2. A grinding machine including an upright frame, and comprising in combination therewith, a stationary trough member extending across the frame horizontally, said trough member having a bottom wall, an apertured end wall, a front wall, and an open top, a work table including depending side walls and a depending front wall,

said table walls fitting within the contines of the open top of the trough member, means rockingly supporting the table upon the stationary trough member for movement from a horizontal position to inclined positions, a bracket upstanding upon the bottom wall of the trough member, said bracket including a bored boss at the upper end thereof elevated above said bottom wall a distance equal to the elevation of the aperture in the trough member side wall, an internal bored boss surrounding said side wall aperture, a clamp shaft within the trough member beneath said table, the shaft having a headed end and a threaded end, the headed Vend being received in the bracket bore with the head abutting the bracket, and the threaded and passingthrough the end wall aperture to the exterior of the trough member, a pair of longitudinally slotted arms depending from the table near opposite ends of the latter, with the clamp shaft passing through the slots of the arms, a loose sleeve surrounding the shaft and having opposite ends each abutting one of the slotted arms, maintaining one of the arms in substantial contact with the boss of the bracket, and the other in contact with the internal boss of the trough member side wall, and a hand nut on the threaded end of the clamp shaft, said nut abutting the trough member side wall exteriorly thereof, and serving when advanced along the threaded end of the shaft, to draw the boss of the bracket toward the end Wall boss, thereby to bind the slotted arms against the ends of the intervening sleeve.

References Cited in the le of this patent UNITED STATES PATENTS 82,828 Hagaman Oct. 6, 1868 238,366 Doane Mar. 1, 1881 409,337 Rich Aug. 20, 1889 1,387,646 Hansen Aug. 16, 1921 1,404,605 Hansen Jan. 24, 1922 1,701,814 Maddox Feb. 12, 1929 1,972,160 Osterholm Sept. 4, 1934 2,021,602 Jackson Nov. 19, 1935 2,175,347 Granberg et al Oct. 10, 1939 2,292,229 Krueger Aug. 4, 1942 2,361,550 Krueger Oct. 31, 1944 2,374,716 Wiken May 1, 1945 2,512,303 Butler June 20, 1950 2,538,532 Oliver Jan. 16, 1951 FOREIGN PATENTS 110,446 Germany May 7, 1900 119,216 Australia 1944 Great Britain June 28, 1944