US2189060A - Typewriting machine - Google Patents

Description

Feb, 6, 1940. w. A. DOBSON TYPEWRITING MACHINE Filed Oct. 22, 1936 2 Sheets-Sheet 1 ATTORNEY.

Feb. 6, 1940. w DQBSON I 2,189,060

TYPEWRITING MACHINE Filed Oct. 22, 1936 2 Sheets-Sheet 2 Patented Feb. 6, 1940" TYPEWRITING MACHINE William A. D obson, Wethersfield, Cnn., assignor v to Underwood Elliott Fisher Company, New

York, N. Y., a corporation of Delaware Application'October 22, 1936,SerialNo.106,973

3 Claims. (01. 197 -27) This invention relates to portable typewriting machines.

Desirable properties or virtues in portable typewriting machines includecompactness, that 5 is, minimum over-all dimensions so that the portable typewriter can be packed in brief-cases,

suit-cases, valises, or other'convenient carrying containers; lightness, so that the addition of the portable typewriter to the baggage or luggage will not be too 'b'urdensome an encumbrance to anyone, evento young students; strength and durability; lightness and smoothness of keylever action'and sufiicient power in the type impact to produce a number of clear carbon copies;

freedom from undue canting of the keys when the typewriter is actuated so that the fingers do not slip off the keys while typing; accessibility of all the parts ,formanufacture, adjustment, or

repair; sharp, clear, and regular type impressions; 'saleability; low-cost manufacture; visibil ity; a" standard keyboard having a full complement of 44 keys and 44 coacting type-bars; platen case-shifting for upper and lower case type; a printing line having sufficient letterspaces to utilize standard business letter-head copy sheets or legal-size paper; and general attractiveness and pleasing appearance of the typewriter.

In approaching the problem of creating a portable typewriter that will have the above enumerated virtues or desirable qualities, it is evident that the minimum width possible is predetermined by the width of a standard type writer keyboard with' standardtype-faces, and the length of a platen requisite to accommodate lines of' sufiicient length to permit the use of the legal and business copy sheets now customarily used. In procuring compactness of a portable typewriter reduction in the height and re- '40 duction in the front to rear dimension may be made so long as the reductions'do not impair or detract substantially from other desirable qualities or virtues enumeratedabove, so therefore-the compactness of the, type-action, pro- 45 vided that other desirable'properties of the typewriter are not sacrificed or impaired, may be directly related to compactness of the typewriter as a whole. The present'invention is directed to the provision of improvements in typeactions with a view toward their utility in port-- able typewriters, more especially in reducingthe height of the typewriter and in reducing its front to rear dimension. f r

The presentinvention provides in a portable typewriter the combination/with an array of I type-bars pivotally mounted near the bottom of the machine to swing toward the platen rear- .wardly and downwardly from an initial inclined position extending forwardly and upwardly, of a set of key-levers that are fulcrumed on-pivots 5 which lie in a straight line substantially in the transverse vertical medial plane of "the, type-" writer and substantially in the horizontal medial plane of the typewriter in front of and underneath the array of quiescent type-bars and that coact with, to accomplish the type-action, sublevers, one under I each key-lever; pivotally mounted on a reinforcing straight crosspiece that lies below and in front of the key-lever pivots but spaced therefrom to permitthe insertion of type-bar links therebetween, each sub-lever having an upwardly extending arm pivoted to a type-bar link and a forwardly and upwardly projecting arm forming an acute angle with the other armof the sub-lever, the upper edge of the forwardly and upwardly extending arm providing a camming surface which swings forwardly and downwardly under downward pressure by a side pin mounted on the corresponding adjacent key-lever in one form, the side pin ap- F proaching the sub-lever pivot to gradually in- .crease the key-lever resistance towards the end of the stroke while at the same time the link connection with the end of the type-bar is so arranged that the leverage on the type-bar is i 0 increased and the velocity of the type-bar towards the platen is accelerated; andfin the other form of the invention a lever arm is formed on the end of each key-lever and a coil spring connected to the end of this lever. arm and to a sub-lever, so that the tension of the spring gradually increases to a maximum at the end of the key-lever stroke. In the first form of the invention a restoring spring may be secured to a fixed cross-piece in the frame and to 40 each sub-lever. The actuating side pins may be placed in different positions on the key-levers of various rows and in various positions from the center toward the side, andlikewise a plurality I of sub-levers may be formed having camming edges of varied angular inclination, to be positioned variously under key-levers of different rows or under key-levers of various distances from the center.

A modification of the invention involves the provision of sub-levers pivotally mounted on a reinforcing crosspiece below and adjacent the type-bar comb, each sub-lever having an arm depending vertically from the fulcrum point and an arm inclined rearwardly and upwardly and Y55 provided with an inclined slot for engaging the key-lever side pin. This construction permits of the use of somewhat shorter key-levers than the I other form of sub-levers. The positionsof the key-lever side pins may be varied and the shape of the sub-levers, for key-levers of different rows and different distance from the center. In this form of the invention a recoil spring is fastened intermediately on the vertical arm' and connected witha lever arm formed on the end of the corresponding actuating key-lever.

The positioning of the key-lever pivots in the transverse medial vertical plane underneaththe forwardly and upwardly inclining quiescent typebars permits the full height of the typewriter to be substantially measured by the horizontal planes through the tops and the bottoms of he inclined quiescent type-bars, because theelimination of the necessity for the space underneath the type-bars for an arrangement of key-levers permits the type-bar pivots themselves to be placed practically at the bottom of the typewriter,

so that by using short type-bars and inclining them at a low pitch, a typewriter may be constructed that is easily slipped into a brief-case because of its small height, but without sacri- -ficing any of the requisite or desirable virtues in a portabletypewriten. The positioning of the.

key-lever pivots substantially in the medial horizontal plane provides ample room for the vertically arranged sub-levers and forkey-levers of sufficient length that they can actuate the typebars with a light, smooth touch on the keys and without undue canting of the key-levers to such an inclination that the finger of the typist might slip 01f the front edge of a key. In either form of the invention the crosspieces form a strong reinforcement of the frame of the machine.

Other features andadvantages will hereinafter appear.

Figure 4 is a left side elevation partly in section and illustrating one form of the invention,

the top, bottom, front and rear of the complete typewriter being shown in broken lines.

Figure 5 is a plan View, parts broken away, of

the form of the invention shown in Figure I.

The left key-lever shown is at the right of the center of the machine.

A portable typewriter has a casing It), a platen H at the rear, and a rearwardly and upwardly inclined type-bar segment i2, having an arcuate' pivot rod 53, on which are mounted type-bars I i, adapted to strike downwardly andrearwardly on the platen H.

From the bottom of each type-bar M depends an arm 55 to which is connected a link It having an angled bend ll therein. The links It connect with the other part of the type-action as will be hereinafter more fully described.

The typewriter shown has the standard keyboard having 44 keys 58, arranged in four rows or banks, each row toward the rear being higher than the row immediately in front, as clearly shownin Figure 1; 7

Four rows of key-levers l9 likewise have 'ho-rizontal forwardly and rearwardly extending parts positioned at different heights in co-relationship with the keys l8 which they support. All of thekey-levers I 8 are pivoted on a horizontal straight.

pivot rod 29, fixed in a cross-pieceZl, mounted in the sides of the frame '22 of the machine; This pivot rod 20 is preferably positioned substantially in both the horizontal medial plane of the typewriter and the-transverse vertical medial p1ane.. By reference to Figures 1 and 4, it is evident;

that the locus of the pivot rod 25 is also below intersection of the horizontal and verticatme dial planes of the type-writer is thelocus of the pivot points of all of the four banks of keylevers is the first step in the discovery of an answer to the problem of how to construct the most compact, low-cost portable typewriter with- 1 out sacrifice of the good qualities possessed by a This pivot locus provides for key-levers 8930f sufficient length that the de- 7 standard typewriter.

pression of keys i8 does not causeso much canting of the keys 18 that there is danger of a finger slipping off the-front of a key; during typing. This location of the reinforcing and supporting crosspiece 25' in the frame 22 is central and (3011*.

duces to'the strength, lightness and rigidity of the machine. The pivot rod 26 is also sufliciently high that there is plenty of room for the depression of the front row of key-levers It. The location of the pivot rod 2i under-thetype bars M also permits the location of the keysnear the quiescent inclined type-bar heads 23 conducing to a minimum dimension, front-to rear, for a portable typewriter havinga standard keyboard and type-bars of ample length to aiford the j requisite velocity of type-bar impact on the platen II, as well as conducing tofa minimum lheight measured by an inclined type-bar because the need for space beneath the bottoms of the typer I bars 14 for the key-levers lfi is entirely elimif nated.

Each key-lever l 9 is heldat the rearjina space ingand guide slot 25 formed in the crosspiece 25.

At the side of each key-lever i9 is mounted-La laterally projecting pin 26. Referring to Figures 3.

1, 2 and 5, this pin 26- contacts and overlies an inclined cammingarm- 21.1"

Each key-lever i8 is guided at-the front in slots 28 in the combZil, secured intheframe 22' of the typewriter. Each lateral pin 26 contactsthe upper edge of. the camming-arm'z'i at a point considerably to the right of a straight transverse pivot rod 31'! on which the sub-levers 3! are pivoted in vertical slots 32 inthe crosspiece mounted in the sides of the frame 22 at the bot- 1- tom of the typewriter below andin front of the crosspiece 2!. vertical but rearwardly inclined arm 34,.provided with a pivot hole 35, in which issecuredthe forward end of a link it. Restoring springs Sfi-may also be secured to the arms 3d and to a crosspiece 31, mounted in the frame 22 of thetypewriter. Inasmuch as the pivot .rod 241 is to ;the

Each sub-lever 3,! has a nearly rear of and above the pivot rod 36, when and as a key I8 is canted down, the associated pinjfifi vmounted on the key-lever It moves towards the 7 v sub-lever pivot 30 and so lessens the effective leverage of the camming arm 21, therebmfin j rearwardly inclined slot 42. j are pivoted in spacing and guiding slots and on conjunction with the coil spring 36, relieving the harshness which would otherwise make the keylever action unsatisfactoryto the average typist.

As is shown in Figure 2, sub-levers 3| are provided with four differently inclined camming arms 21 adapted to snugly engage pins 26 on four different rows ofkey-levers H9 in a standard keyboard.

Referring to Figures 1 and 5, a universal bar 38 is supported at either end by a depending arm a straight rod 43, mountedon the rear inclined edge of. a crosspiece 44 mounted in the sidesof the frame 22.

A spring' tdis tied to anear 46, formed on the 7 rear of the sub-lever Ml, and to an arm' 59, de-

latter is driven by the key-lever in thepr-inting pending from the key-lever I9. The' lower front edges of the sub-levers 49 contact and actuate a universal bar 41, mounted on arms 48, depend- H ing from the outer ends of rocli shaft 49.

It is obvious that as a key-lever I9 is depressed the arm l5 and sub-lever 46 move apart and increase the tension on the key-leverjlii to a maximum at the end of a stroke, thereby cushioning the finger and making a pleasant touch.

Variations may be resortedto within the scope of the invention, and portions of the improvements may be used without others.

Having thus described my invention, I claim: ,1. In a portable light-duty typewriting ma chine having a platen and a full complement of swingable type bars having upper and lowercase types a type bar fulcruming segment inclining forwardly and downwardly from the platen sub-' stantially to the bottom of the machine so that the type bars in their rest positions incline upwardly and forwardly toward a level substantially no higher at their type ends than the top of the platen, and strike downwardly and rearwardly upon the platen, a system of key levers presenting a plurality of transverse key rows substan- I ytially no higher than thelevel of the top of i the platen, said key levers being swin'gable about a common transverse fulcrum axis disposed forwardly of the type bar fulcruming, segment in close proximity to the central type-bars at rest,

" a system of sub-levers having a common. transverse horizontal fulcrum axis forwardly of and below said key lever axis, saidsub-levers presenting substantially uniformupright type-bar operating arms reaching above the key levers, a system of pull links individually connecting said sub-lever arms to corresponding type bars and reaching across the system of vkey levers and beneath the fulcrumaxis thereof, a pin and single- .sided cam-edge connection between each key lever and a corresponding sub-lever whereby the stroke of said key-lever, and a system of springs directly connected to the sub-levers to restore .any operated type bar together with its sublever and key lever. I

2. In a portable light-duty typewriting' ma chine having a platen and a full complement of swingable type bars having upper and lower case types; a type bar fulcruming segment. inclining forwardly and downwardly from the platen substantially to the bottom of the machine so that the type bars in their rest positions incline upwardly and forwardly toward a level "substantially no higher attheir type ends than the top of the platen, and strike downwardly and rear wardly upon the platen, a system of key levers presenting a plurality of transverse key rows substantially no higher than the level of. the top of the platen, said 'key levers, being swingable about a common transverse fulcrum axis disposed forwardly of the typebar fulcruming segment, a system of sub-levers having a common 'transverse horizontal fulcrum axis forwardly of and below said key lever axis, said sub-levers presenting substantially uniform upright type-bar-operating arms, a system of pull links, individually connecting said sub-lever, arms to the corre sponding type bars, each sub-lever also presenting a single cam edge extending forwardly from the type-bar-operating arm and engaged bya pin or'the like of the corresponding key lever, whereby the key lever in its printing stroke drives said sub-lever, and a system of springs directly connected to the sub-levers to restore any operated type-bar, together with its sub-lever and key lever, the several cam'edges and companion pins having different dispositions consonantly with uniform printing stroke depressions of the keys of the several key levers and different extents of swing of the type bars to the platen.

3. In a portable light-duty typewriting ma: 3

chine having a platen and a full complement of swingable type bars having upper and lower case types; a type bar fulcruming-segment inclining forwardly anddo-wnwardly from the platen substantially to the bottom of the machine so that the type bars in their rest positions" incline upwardly and forwardly toward a level substantially no higher at their type ends than the top of the platen, and strike downwardly and rearwardly uponthe platen, a system of key levers presenting transverse fulcrum axis disposed forwardly of the type bar fulcruming segment in close proximity tothe central type bars at rest, a system of sub-levers having a common, transverse, horix a plurality of transverse key rowssubstantially j no higher than the level of the top of the platen, said key levers being swingable' about a common zontal fulcrum axis disposed forwardly of said key lever axis and presenting upstanding type operating arms reaching above the key levers, a

system of pull links individually connecting said sublever arms to the corresponding'type bars and reaching across the system of key levers and beneath the fulcrum axis thereof, a pin and cam I I connection from each key lever to the companion sub-lever, and a system of springs directly con- ,nected to the sub-leversto restore any operated type'bar together with its sub-lever and key lever.

WILLIAM A. DOBSON.

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