US2642841A - Line-spacing copyholder - Google Patents

Description

June 23; 1953 R. FUNK LINE-'SPACING COPYHOLDER 2 Sheets-Sheet 1 Filed July 7, 1950 Rudblfih 531%. fin, v ATTORNEYS.

R. FUNK LINE-SPACING COPYHOLDER June 23, 1953 2 Sheets-Sheet 2 Filed July 7, 1950 INVENTOR 22 RwdoZp/u Funfd.

Patented June 23, 1953 YUNITEDSTATES PATENT oF Icr.

Rudolph Funk, Ivyland, Pa.

" Application July 7, 1950, Serial No. 172,397

This invention relates to line-spacing copy holders. v

Copy holders of the general type here involved have become well established in the typing art as an aid and facilitator of copying, line-for-line, material mounted on the copy holder. However, the only known commercial embodiments thereof have 'been possessed of numerous defects and disadvantages and have been unduly expensive. As hitherto provided they'have generally comprised permanently mounted devices, anchored on the desk behind and extending above the typewriter, thus requiring wide andflargely unused copyholding area; the holder has generally been completely vertical so that the lighting and therefore reading of the copy have been trying on the eyes of the operator; they have conventionally been operated by a small extension treadle comprising a long lever with a small fiat striking area connected to the copy holder at one end and disposed on one side of and beside the typewriter, requiring one hand use through a necessary long stroke; it has been difiicultto have the copy held and read close to the top of the copy holder or to extend above the top, if desired, owing to the limiting nature of the paper clamp used; and the working mechanisms have been exposed to an undesirable degree.

It is among the objects of this invention to improve the art of line-spacing copy holders, both in general and in specific details; to providean improved line-spacing copy holder of simplicity, beatuy; and cheap manufacturing costs, which has high utility and adaptability to change of size of copy held-and of the line. spacing utilized; to provide a copy holder operated with a treadle or foot member extending completely across the copy holder so as to be operable with ease with either hand; to provide an efiicient line-spacing copy holder in which the operating mechanism in large measure is behind the holder to preserve the superficial simplicity of the holder; to provide a copy'holder with a line spacer which is automatically adjustable to various thicknesses of copy without disturbance of its line-spacing functions; to provide a line-spacing copy holder formed of stampings so as to be cheap and simple to construct; to provide a line-spacing copy holder which is strong and rigid in use but which is portable and small enough to be placed in the drawer of a desk to permit the associated typewriter element to be folded away with the closing of the desk; to accommodate either single or double spaced copy work or any increment thereof; to provide adjustment of angle Qf board at 8 Claims. (Cl. 12034) operators discretion; and other objects and advantages will become more apparent as the de- I scritpion proceeds.

In the accompanying drawings forming part of this description: Y

Fig. 1 represents a perspective of the copy holder of this invention in its operative open easel mounting as placed, for instance, on a desk beside or behind a typewriter for easy operation. Fig. 2 represents a front elevation of the copy holder according to a preferred embodiment thereof. 1

Fig. 3 represents a side elevation of the copy holder. of Fig. 2 partially broken away to show the 'mounting of the rear support.

plate of the copy holder,and the carriage in'its mounting on the side edge gauge rail, also showing in full lines the adjusted position of the treadle control with the associated cam set for single line spacing, showing the movement of the treadle-operated bell crank in dotted lines,

and also showing by a second dot-ted lineposition the treadle position when used for double showing the relation of the carriage to the side uide rail. The basic structural unit comprises a frame I0, preferably a stamping, comprising the planar sheet ILhaving the upper rearwardly extendmg flange I2, the rearwardly extending side flanges l3 and I4, and, at the lower end, the

forwardly extendingpaper or foot rest flange l5, bentover uponit'self to form the forward paper-v retainingridge [6. The plate, as apertured with various openings in the flanges, to be described,

is a simple punching or stamping as a finished entity. To the rear of the plate close to the lower end thereof, a rearward downwardly inclined bracket I! is rigidly attached, as by spot welding or the like. The bracket |'I comprises an upper planar portion l8, superimposed against the rear face of the plate II, and having the downwardly and rearwardly angularly divergent planar portion merging into the angular terminal foot flange or extension 2|. The latter is suitably provided with deskcontacting elements, such as the rubber or like feet 22, at opposite ends of the terminal flange 2| transversely of the plate The bracket |1 carries laterally spaced ears suitably bent out of the plane of the flat portion l8 to form two parallel rearwardly projecting supp rting arms 23 and 24. Arms 23 and 24 form pivotal supports for the treadle bell crank levers 25 and 26. As these are identical except in one small regard which will be pointed out, each bears identical reference character. Each bell crank lever has a central pivot arm 21 connected to fixed support arm 23 or 24 by a pivot pin 30, or the like, suitably disposed relative to the respective juxtaposed arm to permit the tilting of the respective bell crank levers on pins as common coaxial pivots. Each bell crank has a free upper end 3| or an arm 29, and carries a rubber or similar cushioning stop or stud 32 presenting toward the rear face of the plate Each bell crank has a lower end comprised of a forwardly projecting arm 33 having an inturned foot 34 fitting into and secured to the bottom of the median plane between the flanges of the angled finger treadle cross piece member 35, extending completely across, below and in front of the copy holder plate The treadle assembly thus described has the upper outer exposed face of the angle member 35 disposed just beneath and in front of the copy or paper foot rest flange |5, at the lower end of the plate The bell crank and-angle members form a rigid pivoted unit. The treadle is biased toward an upper position from which it is deflected by the fingers of the operator by means of a vertical rack bar 36 for actuating the carriage, to be described, pivoted to bell crank lever 26 by a horizontal pivot pin 31 passing through a pivot aperture 38 formed in the bell crank lever 26. plastic rod of any desired profile and construction, but which is preferably substantially oblong in cross section, and has a series of downwardly sloping teeth 4|! presenting rearwardly of the rear face of the plate H, to which plate the rack is juxtaposed in substantial parallelism. The upper end of the rack, as at 4|, is reduced in size, while establishing or maintaining angularity of cross section, and passes through a correspondingly angular guide hole 42 punched or stamped in the upper rearward flange 2. The rack 36 is disposed inwardly of and generally parallel to the side flange |3 of the plate behind which, and the superposed guide rail, to be described, it is substantially concealed. To impress an upward bias on the rack, a suitable tension spring 43 is provided, anchored to the flange l2, as by being threaded through one or more apertures 44 thereof beside guide aperture 42 therein. The lower end of spring 43 is secured on a pin 45 rigidly projected horizontally laterally of the rack 36 so that the tension of the spring is substantially parallel to the rack and urges the latter upwardly relative to its guide aperture 42 in which it is held and guided The rack bar comprises a metal or against change of angular positioning. The upward pull on the rack from spring 43 effective on the bell crank 26 to which it is pivoted pulls the treadle up into operative position, from which it is subject to being depressed by the fingers of the operator. Obviously, through the connections shown, the depression of the treadle by the operator causes a, proportional axial downward movement of the rack against the urge or bias of the spring 43.

An important feature of the invention lies in the provision of a side guide rail by which the carriage to be described is guided and which also serves as a lateral aligning shoulder or edge for the plate [I by which copy can be aligned on the plate I. The guide rail comprises the fiat elongated plate 50 generally rectangular in cross section, rigidly aflixed to the side flange |3 of the plate H and forming front and rear parallel edges 5| and 52, extending the full length of the copy holder, from an upper edge substantially coincident with the upper flange l2, to a lower termination well beyond the termination of the side flange l3, for a supporting purpose to be described. It will be noted that the forwardly presenting edge 5| extends forwardly of and beyond the plane of the plate H to form a side edge guide for the copy, provided by the flat portion 53 of the rail 50 extending forwardly beyond the plate.

A traveling line-spacing carriage 54 is provided comprising apertured side plate 55, carrying four studs 56, journalling four guide rollers 51, and each having a peripheral groove 58 Within which the edges 5| and 52 respectively are received. The rollers are disposed in vertically spacedpairs to engage the opposite edges 5| and 52 of the guide rail. The rollers and guide rail are so disposed that the carriage 54 has positively guided but free sliding engagement with the guide rail, subject to frictional restraint from the bowed flat spring 39, the ends of which are in apertures 49 of the side plate, so that the bowed center frictionally engages the side of the guide rail 50 to hold the carriage wherever it is set, while permitting restrained motion thereof whenever the rack is axially moved downwardly, as will be explained. The plate 55, toward the front of the assembly, is bent angularly to form a concealing panel 60, terminating in the in-bent flange 6|, forming the front exposed portion of the carriage. The plate 55 is prolonged at the top and bottom of the carriage in the horizontal ears 62 and 63, within each of which is formed elongated slots 64, the long axis of which is parallel generally with the planar extent of the side plate 55. The ear 62 is continued forwardy in a fingerpiece 65. A bell crank lever 68 is pivotally mounted on horizontal pin 61 externally of and upon the side plate 55 of the carriage 54. Bell crank 68 at the forward end terminates in a finger piece 10 juxtaposed to the fixed finger piece 65.

The rear end of the bell crank lever carries a rearward offset 69, upon which is mounted. forwardly extending pawl or trigger device 1 I, having the sharpened tip 12 for engaging or sliding over the respective teeth 40 of the rack. A tension spring 13 connects the rear arm of the bell crank lever by mounting aperture 19 therein with a stud 89 on the side plate 55 to bias the pawl end 12 of the bell crank into engagement with th rack teeth. The juxtaposition of the fixed fingerpiece 65 and the fingerpiece 10 of the bell crank lever 68 is such that by gripping same with the thumb and forefinger, the operator can withdraw pawl II from the teeth. to releasethe 'carriagle 54' for manual adjustment vertically'of theplate II against the friction of spring-device, s

The line-spacing element of the assembly coinprises an elongated strip of more orlesshea'vy sheet metalor plastic material or the like I5, having a free end carrying an extensionto be described, and having an anchored pivoted end formed of an angular extension 'IB, oarrying pair of parallel spaced-ears 17' relative to which preferably the spacer I5 is asymmetrical, being close to the lower car 11. The ear'spacing is just sufficient to permit the ears TI to slide easily between the ears 62 and 63 on the carriage, with aligned pins'IB of the element mounted on the ears TI disposed in the respective slots 64. This permits free pivotal motion relative toplate'II for inserting or removing copy and also effects variable clearance for the copy. With no paper or only a thin. paper. orlike-copy on the panel II, with the easel tilted rearwardly,-the pins -18 move inwardly gravitationally in the elongated slots to bring the rear face of thestrip 15 against and inparallelism with the front face of the plate'II' and the thincopy thereon; With additional thicknesses of copy material the entire strip l5 and its mounting ears move forwardly parallel tO'the plate H by pin movement in'theslotsfi l, until it rests gravitationally against the outer face of the thicker copymaterial. Toutilize'the line spacing for work or copy of greater width than the plate I I, an extension is provided for the relatively heavy strip 15. To this end strip "I5 carries the pivoted, relatively short, and relatively thin ex tension strip 82, anchored to the strip I5,as:by a rivet 83 close to the free end of strip I5. Thethin strip 82 normally is concealed behind strip I5 and is retained in an inoperative position by friction. When desired, the extension 82 is swung out" wardly about rivet 83 to aligned position with the effects to be realized efficiently and expeditiously,

two angle pieces, respectively 90 and SI are pro vided, each comprising a flat portion for contacting the rear surface of the plate I I, to which they are rigidly secured as by spot welding or the like. each having an upstanding flange 92 perpendicular to the plate II. Preferably each flange is provided with a series of apertures 93, with the apertures in horizontally spacedpairs in respective horizontal alignment transversely of the flanges 92. A resilient rod is bent into. U shape to provide legs disposed in two obtusely angular integral courses having a lower cross connection 98 carrying the rubber or like bumpers 9 1 at the end of courses 98, and. the latter terminat in short obtusely divergent foot courses S9. The

outer sides of the legs carry two studs, respectively I00 adjacent the bend between leg courses closer to the cross connection, and I M outwardly thereof in foot courses 99. The studs I00 are pivotal studs, which, mounted in aperture 93, permit the supporting rod to be swung from aposition with the cross piece closer to the rear surface of the ture to hold the legs out'during manual'manipu lations of thecopy' holder, while permitting the supporting legs to be collapsed for shipping and storage. The short leg courses 99 are parallel to plate II, while the longer courses exte'nd angularly away and downwardly from plate II. Thus, the angle of tilt of the copy holder can be easily changed, While securing rigidity. in the selected. disposition.

- :As an aid to holding and folding legs against the plate I I during shipping or storage, it is preferred to have the rubber buttons 32' so disposed and of such diameter as to lie in the path of collapse of the folding legs so as frictionally to hold the legs inwardly against the plate I I. If desired, this can be accomplished by having the ears 3! extend far enough as to intersect the'folding: legs and past which-the folding legs can snap in either direction, under gentle manual urging. The rigid support of the tilted-plate II is withthe rubber bumpers 91, and 22, resting in spaced relation on a fiatpsurface such as'a desk.

A further-important feature of the invention. lies in thesimplicity and effectiveness of the copy clamp, by which,.when desired, the copy material or Work can beheld against the plate iI, while permitting free ,movement'of the carriage relative to'the work. The "clamp preferably utilizes a uniquely shaped piece of bent rod IIO. -At the I this is provided with an, axial slot II2. This straight end is inserted parallelto the plate I I,

through an aperture formed in the side fiange I4 at. II3. This end III is thusbehind the plate II. The rod is then bent at right angles in adownwardly extending course I I4, and leads through a right-angled bend into the clamping portion H5 overlying and parallel with the front surfaceof the, plate II. '1

The clamping portion II5 carries rubber bumpers or friction devices IIS and terminates close to. but spaced from the side guide rail 50, at which point it bends through a right angle into the vertical forwardly inclined course II'I leading well above the plate II. At this upper level the rod is again bent in a right angled turn into a finger or thumb. piece I20, generally parallel to .the. platev II and, in front of the plane thereof. right angled bend leads into a downwardly and rearwardly extending extension I'2I, outwardly beyond the guide rail 50. Finally, thelatter course of the rod leads through a. still further right angled turn into-the horizontally extending relative short extension comprising a pivot piece I22 coaxial with thepivot piece III and extending through an aperture I23 in the guide plate 50- and the side flange I3. By inserting the longer pivot end II I intoits aperture first, the last mentioned end I22 can be sprung'into position by bending the rod against its inherent resilience. I I I "In order to impose a clamping bias on the clamp, which is symmetricalon'both sides, it is preferred to providethe torsion spring I30'enclosing the longer pivot end III, withone end of the spring anchored inthe slot I I2, while the The thumb portion through a further outer end of the spring abuts and bears against the inner surface of the plate II, as indicated at I3I. Any desired mode of limiting the inward axial motion of the pivotal end'III may be resorted to, as by upsetting or swaging the rod outwardly of the flange, as at I32. To properly bias the other end of the clamp a torsion spring I33 has one end anchored in an aperture in the side rail 5|] and side flange I3, and has a terminal extension engaging against one side of the rod extension I2I.

It will be seen that by the construction of clamp just described, instantaneous release of the grip of the clamp is secured by rearward pressure on the thumb piece I20 above the upper edge of the plate II, so that one handed operation is attained, leaving the other hand free to adjust the paper on the work surface I I. At the same time, it is to be observed that the formation at the left hand edge of the copy holder is such with the two vertical legs Ill and I2I connected by the elevated cross piece I20, that a generally rectangular space is defined into which the upper end of the carriage can freely move, in order to have the line-spacing element 75 start its spacing functions close to the upper edge of the plate II immediately adjacent to the clamp II5. This is an advantageous feature of applicants structure which is not attainable with any other known device for the same purpose. This is obtained without sacrificing adequate gripping and clamping of the copy work on the work-holding surface of plate II. As the clamp goes on so readily, as described, so also can the left hand side thereof at'least be freely released and moved out of the way if for any reason it is desired to slide the carriage vertically off the end of the side guide plate 50, as for inspection, repair, lubrication or the like.

It will be seen that as so far described the operation of the device is simple and expeditious. With the work in place and superposed, regardless of thickness, by the overlying spacing bar 15, and with the carriage provided with a suitable friction preventing it from unrestrained sliding on the track 50, each downward motion of the treadle is accompanied by a downward pull on the rack. As the carriage is coupled to the rack by means of the biased pawl II, the carriage will move downwardly so far as the rack moves, thus sliding the space bar I5 downwardly relative to the work. At the lower end of the downward stroke of the treadle, when the rack stops, the carriage is frictionally held against the side rail 50 so that release of the treadle permits the upward retraction of the rack under the influence of its spring, which slides the rack relative to the carriage by causing the pawl 'II to slide over the sloping teeth surface until the rack attains its upward normally biased position. This will be repeated as often as the treadle is depressed and then released. Owing to the width of the treadle, as noted, it will be observed that it may be manipulated anywhere along its width, or toward either end thereof.

In most cases it will be preferred that the treadle motion be arranged for selective limitation so that one or two lines or more may be quickly predetermined and the mechanism changed to secure the desired result. To this end a modification is made of the bell crank lever 25, to provide a lateral offset stop or abutment 26' extending outwardly toward the guide rail 50. A fingerpiece MI is journalled on a pivotal pin I40, mounted in the lower extension of the side guide rail 50 for operation by a finger of the operator. The fingerpiece I has the lateral ofi'set I 42 for facilitation of engagement by the operator, and is affixed to the cam element I43. journalled on pin I40. The cam is made of suitable cushioning material, if desired, although it may be a plastic device having little cushioning and has a short rise I44 arranged to abut the rear surface of the plate I I adjacent to the work rest flange I5 in one angular position, while extending a longer cam element I45 at such angle as to be abutted by and to the upward motion of the stop 26' and thus to limit the motion of the bell crank 26 in one direction in said one angular setting. The disposition is then as shown in Fig. '7 with a single spacing of the carriage for each complete depression of the treadle. This is accomplished by moving the fingerpiece I42 to the rear limited by the abutment of the short cam portion I44 against the plate II. To double the length of permitted treadle travel, the fingerpiece I 42 is moved forwardly to bring the side I45 of the long cam portion against the lower surface of the rest I5 as a stop, while bringing a surface I46 into position to be abutted by the stop 25'. The change is facile and quick, and is from the front of the device, and establishes a quick change of spacing from single to double space, or greater spacings if so set. Usually this change from single to double spacing is sufficient, although it will be understood that with certain modifications of the cam that a greater range of spacings can be effected.

It will be understood as preferable that the teeth of the rack terminate at the bottom of the rack preferably at a point precluding lowering the carriage far enough to contact paper ledge I5.

The ruggedness, simplicity and extreme economy of the invention will be manifest.

Having thus described my invention, I claim:

1. A line-spacing copy holder comprising a plate, means for supporting the plate, a guide rail mounted on the plate perpendicular to the plane thereof and having parallel guide edges each projecting and located beyond the plane of the plate, a line-spacing carriage comprising a frame, peripherally grooved rollers on the frame for guided rolling contact with the said guide edges said rollers being plural spaced pairs respectively engaging opposite edges of said rail, means establishing friction laterally between the carriage and the plate to restrain the guided motion of the carriage, means for moving the carriage step by step downwardly, and a spacing bar pivotally mounted on the carriage and overlying the plate.

2. In line-spacing copy holders, a plate, a guide rail having parallel front and rear guide edges, means mounting said guide rail on the plate perpendicular to the plane of the plate, a carriage comprising a supporting frame, rollers mounted on the frame to straddle and roll on the respective guide edges of the guide rail, said frame having spaced apertures, and a bowed spring element having ends and an intermediate portion, said ends being mounted in the respective apertures and said intermediate ortion bearing laterally against said guide rail as a friction device to limit the sliding motion of the carriage relative to the plate by the linearly extending face of said rail.

3. In line-spacing copy holders, a plate, a guide rail having parallel guide edges, means mounting the rail on the plate at one side of and normal to the plate with th guide edges substantially parallel to the plate with one of said edges spaced forwardly of the plate to dispose the rail oas a lateral work guide, means for supporting the plate by pressure on any part thereof, a line-spacing mechanism comprising a carriage slidable on said rail spaced platewardly of and in the plane of the rail from the plate so as to facilitate use of the rail as a work guide, and a generally fiatbar, means pivotally connecting said bar tothe car-, riage on an axis spaced from said late and from the flat bar parallel to said guide rail, whereby the bar is movable from a position overlying and in substantial contact with said plate, to a position generally normal to the plate to permit the insertion of papers and the use of said rail as a lateral work guide therefor, and means connecting the treadle with the mechanism to movethe mechanism in a step-by-step progress downwardly across the plate in response to actuation by the treadle.

4. In line-spacing copy holders, a frame comprising a substantially planar plate with upper and side flanges extending rearwardly of the plate, a guide rail having parallel front and rear guide edges, means mounting the rail on a side flange with the front guide edge extending forwardly of the plane of the plat to form a side guide edge for copy on the plate, a treadle comprising a pair of bell crank levers and a connecting treadle bar, means mounting the treadle sys tem on and for oscillation relative to the p1ate,-a carriage slidable on said guide rail, a spacing bar mounted on the carriage and overlying the plate,

' its limits in position tobe actuated by an operathrough which an end of said rack extends for rail, means for biasing the rack upwardly and thus holding the treadle system in operative finger-engaging and depressing position. i

5. In line-spacing copy holders, a frame comprising a plate for receiving copy, a treadle device pivoted to the frame and movable in a restricted path, a rack bar pivoted to the treadle device and having teeth, means mountingv the 1 rack bar for guided movement relative to the frame, a guide rail mounted on the frame, acarriage slidable on the guide rail, a bell crank lever pivoted to the carriage, one arm of which comprises a pawl for engaging the teeth of said rack bar, means biasing the bell crank lever to urge the pawl against the teeth, another arm of said bell crank comprising manual means on the bell crank for moving said bell crank against its bias to release the pawl from the teeth for manual sliding of the carriage on said guide rail, said carriage comprising a plate, spaced sets of rollers journalled on the plate and straddling the guide bar, a fingerpiece formed on theplate in juxtaposition to said manual means on the bell crank for receiving digits of an operator and by relative compressing action thereof to release said pawl by moving said bell crank to permit movement of the carriage.

10 o 6, In line -ispacing copy holders, a frame comprising a plate for receiving copy and a forward flange atthe bottom edge of the plate, a treadle devicefpivoted to the frame behind the plate, means; forming stops for limiting the path of movement of the treadle, one of said means being adjustable to establish a different limit for the path of the treadle, comprising a pivoted cam, a fingerpiece mounted for pivotal movement with the cam, means on the cam for engaging the plate in one cam position, means onthe cam. for en-,

oted at one end to the treadle device behind said plate, and having teeth, means mounting the other end of the rack bar for guided longitudinal axial movement of the rack bar generally parallel to the plate, means for biasing the rack bar upwardly to pull the treadle against one of tor, a carriage, means forming a lateral guide on said plate mounting the carriage for guided movement relative to the plate, means mounted movab-ly on the carriage for engaging the said teeth, means biasing the movably mounted means I toward engagement of said teeth, and a linespacing member mounted pivotally on the carriage.

7. In line-spacing copy holders, a supporting frame comprising a plate having parallel edges and an exposed side face, guide means on the plate, a carriage comprising a second frame,

peripherally grooved rollers mounted rotatabiy on the second frame and straddling the guide means engaging the respective edges for guiding the slidable movement of the carriage relative to said plate, apertures in the second frame, a bowed spring mounted in the apertures and bearing laterally against said side face of said guide means substantially parallel to said guide means to frictionallyrestrain sliding movement of the carriage relative to the plate, and means for positively moving the carriage downwardly in a stepby-step movement.

8. In line-spacing copy holders, a frame comprising a plate, carriage guide means mounted on the plate, a carriage mounted on saidguide means for sliding movement thereon relative to said plate, said carriage comprising spaced parallel ears normal to said plate, a line-spacing membercomprising a rod having a guide edge, a con nection extending generally perpendicular to said edge, spaced parallel ears mounted on the connection for parallel juxtaposition to the respec tive first mentioned ears, complemental means on the respective pairs of juxtaposed ears comprising a pivot pin and an enlongated slot the long axis of which is normal to said plate, providing a lost motion for adjustment to various thicknesses of copy, on said plate, said second mentioned spaced ears and said connection being asymmetrical ofthe rod edge so that the rod edge iscloser to one car than to the other, and

a clamping device pivoted to the frame and overlying the plate, said asymmetry permitting the carriage to start from a position close to the upper edge of said plate whil the spacing mem ber edge is aligned with and disposed just below the said clamping means.

RUDOLPH FUNK.

' (References on following page) References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Woodruff Mar. 22, 1898 Coffee July 16, 1901 Edwards July 30, 1901 Stillians Apr. 13, 1926 Ostediek et a1 Apr. 16, 1929 Brietenback July 2, 1929 Ford Apr. 26, 1938 Collin et a1 Dec. 12, 1939 Number Name Date Isreal July 9, 1940 Metcalf Oct. 8, 1940 Moore Feb. 17, 1942 Forsyth Aug. 17, 1948 Crosby Sept. 7, 1948 FOREIGN PATENTS Country Date Germany May 7, 1912 France Jan. 6, 1943

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