US3057449A - Typewriter - Google Patents

Description

oct 9 1962 J. E. THoMsoN 3,057,449

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United States Patent Ollce 3,057,449 Patented Oct. 9, 1962 3,057,449 TYPEWRITER James E. Thomson, Munith, Mich., assignor to Western Stamping Company, Jackson, Mich., a corporation of Michigan Filed Mar. 21, 1960, Ser. No. 16,368 38 Claims. (Cl. 197-22) This invention relates to typewriters, and more particularly to a construction and method of manufacture of relatively inexpensive typewriters usable both as toys and for school and home purposes,

This application is a continuation-impart of application No. 691,340, filed October 21, 1957, now abandoned.

It is an object of the invention to provide a novel and improved typewriter construction which incorporates a standard keyboard and platen arrangement, together with ribbon feed. paper release and other features found on standard office machines but which nevertheless may be mass-produced at extremely low cost from inexpensively fabricated parts.

It is also an object to provide a novel typewriter construction of this type including an improved key lever linkage arrangement which reduces typing elfort while permitting a low and compact shape for the machine housing.

It is another object to provide an improved typewriter construction of this nature which docs not sacrifice accuracy of letter alignment, tracking, spacing or feeding, and permits adjustment to achieve optimum contact areas between the platen and type faces.

It is a further object to provide an improved typewriter of this nature which permits complete testing of the assembled machine on the production line without the necessity of first assembling the housing portions, thus facilitating adjustment of the parts during production.

It is also an object to provide an improved typewriter construction of the above character, including novel hanger .and guide means for the type bars which are of high accuracy, are substantially less expensive than previously known constructions of this nature when produced in large quantity, and which have no wearing parts which might create maintenance problems.

It is another object to provide an improved typewriter construction of this nature which has a novel ribbon feeding and reversing mechanism of inexpensive and eliicient construction.

It is a further object to provide an improved typewriter construction ot' this nature which includes a novel platen construction capable of being fabricated of inexpensive materials without sacrificing the smooth surface quality, resilience or wearing properties of the platen. In this connection, it is an object to provide a novel and improved method of assembly of the platen and platen core which enables the use of such inexpensive material.

It is also an object to provide an improved typewriter of this character including a novel platen ratchet construction which insures accurate feed movement for the platen and at the same time takes up any play between the platen ends and the supporting structure, thus maintaining accuracy of letter spacing.

It is another object to provide an improved typewriter construction having the above characteristics, which includes novel means for holding the paper against the platen, this means eliminating the need and expense of feed rollers and being easily retracted from their gripping position by a simple movement.

It is a further object to provide an improved carriage shift mechanism especially adapted for typewriters of the three position type and which includes means for automatically releasing the intermediate shift lock when it is desired to change to the upper shift position. i

It is also an object to provide an improved carrymg case in combination with a typewriter of the above character, which may be inexpensively fabricated and includes means for securely holding the typewriter while being easily detachable therefrom.

Another object of the invention is to provide an improved and extremely simple means providing independent spring action for each type bar and its associated key and linkage mechanism.

Still another object is to provide an improved and extremely simple and independent means, operable through the agency of a single lever on the carriage, for returning the carriage to the starting position after completion of a line of typing, and at the same time rotatively rolling the platen to position for the next line of typing.

A further object is to provide an improved composite casing structure formed partly of metal and partly of plastic, the parts of which are disposed in a mutually reinforcing relation and which provides a high degree of stiffness yet which is of inexpensive character, and which can be readily opened for access to the parts for lubrication or any necessary servicing.

Other objects, features, and advantages of the present invention will become apparent from the subsequent description, taken in conjunction with the accompanying drawings.

In the drawings:

FIGURE l is a top plan view of the improved typewriter of this invention, with the lid removed, showing the general contour of the base and the keyboard arrangement;

FIGURE 2 is a cross-sectional view in elevation taken along the line 2 2 of FIGURE 1 and showing the key levers, carriage slide arrangement and other portions of the construction;

FIGURE 3 is a cross-sectional view in elevation taken along the line 3-3 of FIGURE 2 and showing the configuration of the universal bar;

FIGURE 4 is a cross-sectional view in elevation taken along the line 4-4 of FIGURE 2 and showing the type bar support and key lever fulcrum;

FIGURE 5 is an enlarged fragmentary cross-sectional view in elevation of the area marked 5 in FIGURE 2 and illustrating the bearing construction between the carriage and carriage rail as well as the connection between the paper gripping springs and the paper guide;

FIGURE 6 is a view of a portion of the mechanism illustrated in FIGURE 5 showing a paper gripping spring in released position;

FIGURE 7 is a cross-sectional view in elevation taken along the line 7 7 of FIGURE 2 and showing the escapement ratchet and associated mechanism;

FIGURE 8 is a perspective view of the escapement mechanism showing the ribbon guide actuating means;

FIGURE 9 is a cross-sectional plan view taken along the line 9-9 of FIGURE 7 and showing the carriage drive spring and associated parts;

FIGURE l0 is a fragmentary cross-sectional plan view taken along the line 10-10 of FIGURE 7 and showing the signal mechanism;

FIGURE ll is a plan cross-sectional view taken along the line 11-11 of FIGURE 2 and illustrating parts of the ribbon feed mechanism;

FIGURE l2 is a cross-sectional view in elevation taken along the line 12-12 of FIGURE 1 and showing the shift key arrangement with the carriage in its lowestA position;

FIGURE 13 is a view similar to FIGURE 12 showing the intermediate shift lever depressed;

FIGURE 14 is a view similar to FIGURES 12 and 13 with the upper shift lever depressed;

FIGURE 15 is an elevational view of one of the shift key lock brackets which also act as adjustable stops for the rest position of the carriage assembly;

FIGURE 16 is a fragmentary cross-sectional view in elevation taken along the line 16-16 of FIGURE l5 and showing the manner in which the part illustrated in FIGURE l acts as an adjustable carriage assembly rest;

FIGURE 17 is a fragmentary cross-sectional view in elevation taken along the line 17-17 of FIGURE 5 and showing the platen construction;

FIGURE 18 is a cross-sectional view in elevation taken along the line 18-18 of FIGURE 17 and showing the feed ratchet pawl spring;

FIGURE 19 is a cross-sectional view in elevation of an apparatus which illustrates the novel method of assembling the platen core and sheath;

FIGURE 20 is a perspective view of the novel typewriter carrying case shown in its closed position;

FIGURE 21 is a cross-sectional view in elevation taken along the line 21-21 of FIGURE 20 and illustrating the front retaining bar of the carrying case;

FIGURE 22 is a cross-sectional view in elevation taken along the line 22-22 of FIGURE 2() and showing the rear retaining bar of the case;

FIGURE 23 is a cross-sectional view in elevation taken along the line 23-23 of FIGURE 21 and showing the releasable catch on the carrying case;

FIGURE 24 is a cross-sectional view in elevation taken along the line 24-24 of FIGURE 22 and showing the manner in which the rear portion of the typewriter is retained by the rear retaining bar of the carrying case;

FIGURE 25 is a developed view of the metal blank which is to form the walls of the carrying case constructed according to the novel method of this invention;

FIGURE 26 is a plan view of the blank which forms the top of the carrying case in its unformed condition;

FIGURE 27 is a fragmentary view of an edge of the carrying case in semi-finished condition showing the manner in which the flanges of the parts shown in FIGURES 25 and 26 intert.

FIGURE 28 is a view similar to :FIGURE 1 showing another form of the invention, the entire upper portion of the casing being removed;

FIGURES 29 to 34 inclusive are views corresponding substantially to FIGURES 2 to 7 inclusive, showing the second form of the invention;

FIG. 35 is a detail perspective view similar to FIG- URE 8, showing the escapement mechanism of the second form of the invention;

FIGURE 36 is a fragmentary sectional plan view corresponding to FIGURE 11, showing the second form of the invention;

FIGURE 37 is a sectional elevational view taken substantially on the line 37-37 of FIGURE 28 and looking in the direction of the arrows;

FIGURE 38 is a view similar to FIGURE 37, showing the shift lever depressed;

FIGURE 39 is a view taken similarly to but showing only a portion of the parts represented in FIGURE 37, and broken away to illustrate parts of the ribbon reverse mechanism, which is shown in a different position;

FIGURE 40 is a longitudinal sectional view of the platen and adjacent parts, corresponding to FIGURE 17 of the drawing of the first form of the invention;

FIGURES 4l and 42 are sectional details taken substantanally on the lines 41-41 and 42--42 respectively of FIGURE 40 and looking in the direction of the arrows:

FIGURE 43 is a sectional detail taken substantially on the line 43-43 of FIGURE 36 and looking in the direction of the arrows;

FIGURE 44 is a bottom plan view of the plastic upper case and lid assembly;

4 FIGURE 45 is a side elevational view of the same; FIGURE 46 is a top plan view of the base plate; and FIGURE 47 is an enlarged sectional detail of the cowle-type key lever spring and adjacent parts.

BASE, FRAME AND KEY LEVERS Referring more particularly to the drawings, the illustrated embodiment of the invention comprises a base plate 31 having foot pads 32 therebelow, a pair of upwardly bent side anges 33, a rear ange 34 and an upwardly and inwardly bent front flange 35. Secured to a forward intermediate portion of base plate 31 is a key lever supporting frame 36 of generally U-shaped configuration having a central leg resting on base 31 and a pair of upstanding side legs 37. A carriage supporting frame 38 is secured to base 31 rearwardly of frame 36. In plan, as seen in FIGURE ll, frame 38 has a generally U-shaped configuration with a pair of side legs 39 projecting rearwardly from the main frame portion which rests on base 31. The forward portion 41 of base 38 is bent upwardly and rearwardly as seen in FIGURES 2 and 5, and the inner edges of rearwardly extending portions 39 of the frame each has a relatively short post 42 and a relative long post 43 spaced rearwardly of post 42. A key lever fulcrum 44 is secured to base 311 forwardly of frame 38, this fulcrum comprising a slotted bar extending across the base. The arrangement of slots 45 in fulcrum bar 44 is best seen in FIGURE 4, these slots being disposed in parallel upstanding relation.

The keyboard of the illustrated typewriter comprises three banks of keys 46. Each key is adapted to operate a type bar having a type face with three characters, a lower case letter, an upper case letter and a numeral or other symbol, this arrangement being well known in the art. Three sets of key levers are provided for the three banks, a set of long key levers 47 for the front bank of keys, a set of intermediate length key levers 48 for the middle bank and short key levers 49 for the rear bank of keys. These levers have similar shapes with upstanding portions on which keys 46 are mounted at three different levels. The inner ends 5l of levers 47, 48 and 49 lit within slot 45 of fulcrum bar 44 in such a manner as to permit limited pivotal movement of the levers about the upper edges of the slots while preventing the levers from being removed from the slots. The forward edges 52 o-f lever ends 51 may be formed in a sloping manner as seen in FIGURE 2 to permit assembly of the levers in the fulcrum slots.

Levers 47, 48 and 49 are each provided with an elongated slot 53, all these slots being transversely aligned at the position indicated in FIGURE 2. Slots 53 are disposed at about the position of the middle bank of keys and serve to connect the key levers with bell cranks 54 which are rockably mounted on a pivot rod 55 supported between legs 37 of key lever supporting frame 36. A guide bar 56 of L-shaped cross section is secured to the central portion of frame 36 as seen best in FIGURE 3, has a plurality of open-ended slots 57 which serve to guide the key levers as well as their corresponding bell cranks 54. Bell cranks 54 are of uniform shape, and their lower arms overlap portions of levers 47, 48 and 49. A link 58 is connected to the upper end of each bell crank as seen in FIGURE 2 and extends downwardly and forwardly, the end of each link being connected to a type bar 59. The connection between each bell crank 54 and each key lever is by means of a tab on the forwardly projecting arm of each bell crank which projects through the corresponding slot 53 in the key lever, levers 49 having forwardly extending portions carrying slots 53 as seen in FIGURE 12.

A front housing plate 60 extends between the forward edges of upstanding legs 37 of frame 36 being secured thereto by tabs 61 on legs 37, and an L-shaped guide bar 62 is secured to plate 60 and extends rearwardly therefrom. Guide bar 62 is provided with a plurality of slots Y 63, as seen in FIGURES 1, 2 and 11, for guiding the upstanding legs of bell cranks 54.

In operation, depression cf a key 46 will cause its corresponding key lever 47, 48 or 49 to be rocked clockwise in FIGURE 2 about fulcrum bar 44, causing corresponding blockwise rotation of bell crank 54 `about pivot rod 55. It will be noted that the key levers all extend below pivot rod 55 so that the pivot rod will not interfere with depression of the keys. During this movement the key lever and bell crank will be guided by the corresponding slots 56 and 63 of guide bars 55 and 60 respectively. It should be observed that the construction is extremely compact and affords a high mechanical advantage for easy typing with approximately equal effort required for all the keys.

TYPE BAR MECHANISM AND HANGER Type bars 59 are pivotally supported by a hanger 64 secured to inclined forward portion 41 of carriage supporting frame 38. Hanger 64 comprises an integral arcuately-shaped member which is preferably fabricated of a plastic material and thus may be mass-produced be injection molding or other techniques which permit the attainment of close tolerances while eliminating the necessity of machining operations. In its cross-sectional shape, as seen best in FIGURE 2, hanger 64 may be considered to be in the form of a block having a plurality of arcuate recesses 65 for the reception of the rounded lower ends 66 of type bars 59. Slot 65 are on imaginary radii extending from the point at which the type faces engage the platen in order to accommodate the circular guide portions 66 of type bars 59 while still maintaining accurate alignment of the type bars as they move from retracted position to typing position. In this connection, it should be noted that the hanger, being of plastic material and therefore adapted to be injection molded, may be formed without burrs at the locations of slots 65 which might interfere with the action of the type bars. A pivot wire 67 of arcuate shape passes through circular guide portions 66 of type bars 59 and is disposed Within a slot 68 in the forward face of hanger 64. The depth of slot 68 is such that wire 67 will project slightly above the slot, and a pair of screws 69 are threadably mounted in the ends of hanger 64, the heads of these screws frictionally engaging the wire ends to hold the wire in position. A mounting ange 71 is formed on hanger 64, and a plurality of screws 72 serve to fasten this ange to frame portion 41 as seen in FIGURE 2. An additional retaining clip 73 is mounted on `the midportion of hanger 64 for holding Wire 67 in position.

The outer ends of type bars 59 are provided with type faces 74 each having three characters as described above. The upper ends of type bars 59 are supported in their retracted position by a type bar rest 75 which is best seen in FIGURE 1. This rest is in the form of a wire secured to upwardly extending legs 37 of frame 36 and having a curved central portion which cradles type bars 59 in an arcuate roW as seen in FIGURE l so that all type bars have approximately the same travel distance between their retracted and typing positions. A bootjack or type bar guide 76' is secured to upwardly inclined portion 41 of frame 38 as seen in FIGURE 4, the bookjack having a pair of upper fingers 77 with portions extending toward each other to provide a guide for the type bars as they approach their typing positions. The lower portion of bookjack 76 is recessed as indicated at 78, and a pair of inwardly directed side flanges 79 are provided on the bookjack as seen in FIGURE 11. A ribbon guide 81 is supported by bookjack 76 for vertical movement, the ribbon guide comprising a U-shaped wire the side legs of which are retained by anges 79 of the bookjack. The lower central leg 82 of ribbon guide 81 extends across recess 78, and the upper ends of the ribbon guide have looped portions 83 for the reception of a ribbon 84.

CARRIAGE ASSEMBLY The carriage assembly is generally indicated at 85 and comprises a pair of carriage brackets 86 which are supported for parallelograrn movement by carriage supporting frame 38. The shape of carriage brackets 86 is best seen in FIGURES 2 and 12. Each bracket comprises a rearwardly extending arm 87 and a downwardly extending arm 88. A rear torsion link 89 comprising a bent wire has a central portion rockably supported by posts 43 of frame 38 and a pair of forwardly projecting side legs 91 which have outwardly projecting end portions 92 passing through apertures in legs 87 of brackets 86. A forward torsion link 93 is similarly formed, being supported by posts 42 and connected to arms 88 of brackets 86. The configuration of torsion links 89 and 93 is best seen in FIGURE l1. The arrangement is such that links 89 and 93 are swingable between a lower position shown in FIGURE l2, and intermediate position shown in FIG- URE 13, and an upper position shown in FIGURE 14, so that brackets 86 will follow an arcuate translatory path. It shouid be noted that the path of travel of carriage assembly 85 from its rest position of FIGURE 2 to its upper position is approximately parallel to a type face 74 when the latter is in its typing position, thus insuring maximum typing contact in all positions of the carriage.

Novel means are provided for preselecting the lower or rest position of brackets 86 so that carriage assembly 85 may be accurately adjusted to insure maximum contacting area between type faces 74 and that portion of ribbon 84 which is tangent to the platen. Brackets 86 are disposed within a pair of slots 94 at the outer ends of frame portion 41, as indicated in FIGURE 16. The lower portion of each bracket 86 is provided with an inclined stop edge 95, and a pair of rest plates 96 are secured to frame portion 41 adjacent slots 94 for engagement with stop edges 95 of brackets 86. The shape of plate 96 is shown in FIGURE 15 which illustrates a single rest plate, the other plate being a mirror image of the one shown. Each plate 96 is provided with a slot 97 which overlies and is aligned with slot 94 of frame portion 41. However, the inner end 98 of slot 97 will normally be above the inner end 99 of slot 94. A pair of elongated attaching slots 101 are provided in cach plate 96 for securing the plate to frame po-rtion 41 by screws 102, as seen in FIGURE l. In this manner, it will be seen that the rest position of carriage assembly 85 may be adjusted by moving both plates 96 up or down. Each plate 96 is further provided `with a shift key lock tab 103, the purpose of which will be described later.

The upper edges of bracket arms 87 have outwardly extending anges 104 as seen in FIGURE 12, and a carriage rail 105 is secured to and supported by these flanges. Rail 105 comprises an intermediate web portion and a pair of upstandirrg race portions 106, seen best in FIG- URE 5. A carriage 107 is disposed above rail 105 and has a pair of races 108 overlying races 106, ball bearings 109 being disposed within the two pairs of races. A cage 110 which is shorter than carriage 107 is disposed beneath the carriage for maintaining proper spacing of ball bearings 109. A pair of stops 111, shown in FIGURE 7, are formed at the opposite ends of carriage 107, these stops being engageable with the edges of cage `110 to provide margin stops for the carriage. As seen in FIGURE 9, a tension coil spring 112 is secured at one end to carriage rail 105 and at the other end to a pulley 113. A cord 114 has one end secured at 115 to rail 105, passes through pulley 113 and is secured at its other end 116 to carriage 107. Spring 112 thus serves to urge carriage 107 to the right in FIGURE 9.

UNIVERSAL BAR AND ESCAPEMENT MECHANISM The escapement mechanism of the illustrated typewriter is generally similar to that described in Patent No. 2,705,553 issued April 5, 1955 to the present appli-

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