US3534682A - Type wheel structure for impact printers - Google Patents

Description

United States Patent inventor Walter J. Zenner 1776 Sherwood Road, Des Plaines, Illinois 60016 Applv No. 683,993

Filed Nov. 17, 1967 Patented Oct. 20, 1970 TYPE WHEEL STRUCTURE FOR IMPACT PRINTERS 7 Claims, 6 Drawing Figs.

U.S.Cl 101/109, 197/49 Int. Cl B4lj 1/60, B41j 1/32 Field of Search 29/159;

[56] References Cited UNITED STATES PATENTS 1,572,233 2/1926 Chamberlin 101/110 2,589,682 3/1952 Dudis 101/109 2,757,775 8/1956 Hickerson... 197/49 3,168,182 2/1965 Bernard et al. 197/55 3,269,306 8/1966 Smilgys 101/110 3,432,018 3/1969 Watanabe eta]. 197/55X Primary l;'xaminerWilllam B. Penn Allurneyl(inzer, Dorn and Zickert ABSTRACT: A type wheel for an impact printer comprising a unitary sheet metal type font bearing embossed type characters arranged in rows and columns, with each column on a separate angularly disposed face portion of the sheet metal type font, which affords a shell of regular polygonal cross-sectional configuration. The shell is braced by a series of polygonal reinforcing members affixed to its inner surface and is releasably mounted upon a shaft that projects through axial apertures in the reinforcing members.

4-2 use I [I], ll I r Patented Oct. 20, 1970 Inventor in mg w TYPE WHEEL STRUCTURE FOR IMPACT PRINTERS This invention relates to type wheels and more particularly to a light weight type wheel and to a method of manufacturing it.

In the typewriter and printing industry, clean, clear and easily legible printing has been achieved with type bar machines using hardened steel type pallets made by a hot forging process. Since, in machines of that kind, only one type pallet or type bar is moved in printing a character, the weight of the type carrying member is not important. These machines, on the other hand, have other disadvantages which designers have endeavored to overcome by the use of type wheels.

The type wheel machines have the entire type font carried on a single unitary member which must be moved to effect the printing of a single character. When conventional forged steel type is used in a type wheel, the wheel is, of necessity, quite heavy and the speed of themachine is severely limited. This weight difficulty has been overcome by molding the character printing portion of the type wheel from moldable synthetic resins or plastics. However, while such materials are readily fabricated and provide a light weight type wheel, the type wheels made in this manner are subject to chipping and wear and the copy produced is generally not satisfactory. These molded type wheels have been improved by electroplating a metallic layer on the molded member and, while this improves the wearing quality and the printed copy, the cost of the type wheel is increased without producing copy as good as that produced by forged type pallets.

Accordingly, it is an object of the present invention to provide a type wheel lighter in weight than a molded type wheel and having the advantages of forged steel type.

Another object of the invention is to provide a type wheel assemblage which may be easily mounted and adjusted on its actuating member.

A further object of the invention is the provision of a simple method of manufacturing a light weight type wheel.

In accordance with the preferred embodiment of the invention, a type wheel is provided which comprises a substantially tubular, thin walled, structure having a plurality of flat surfaces, angularly disposed with respect to one another in a polygonal arrangement. Each of the surfaces preferably has a plurality of character printing type extending outwardly from it for driving a print ribbon against a sheet to be printed. Rigidity is imparted to the tubular structure by a plurality of reinforcing members in the form of disks each having a central aperture and an outer polygonal contour which conforms to the interior of the tubular structure. One such disk is provided for each level of type and each disk is spot welded to the tubular structure.

In the preferred embodiment of the invention the tubular structure is adjustably mounted on a mounting and positioning member, a spring clip being seated in a circumferential notch in a mounting and positioning member to compress a spring washer against the outermost reinforcing disk and to force the innermost disk against a spacer ring. A mounting and positioning member has a collar fixed to it which has a plurality of equally spaced apertures in it for receiving a spacer pin that is fixed in the spacer ring and may be entered into any one of a plurality of equally spaced apertures in the innermost disk. The spacing of the apertures in the innermost disk and in the spacer ring are very slightly different whereby minute adjustment of the tubular type wheel structure with respect to a mounting and positioning member, may be effected.

Preferably, the embossment of the type and the forming of the tubular structure are effected simultaneously by feeding a sheet of steel into a punch and die having cooperating surfaces comprising projecting type character-forming and strip-bending portions on the punch and type character-forming and strip-bending recesses in the die. The cooperating type character forming portions stress the strip of steel beyond its elastic limit to emboss the type in transverse rows on the strip and the bending portions stress the strip beyond its elastic limit in transverse lines between the rows of type characters.

A more complete understanding of the invention may be had by reference to the following detailed description when considered in conjunction with the accompanying drawing wherein:

FIG. 1 is a fragmentary view of a printer showing the type wheel in a cooperative relation to a wheel driver and a paper supporting platen;

FIG. 2 is a transverse sectional view taken substantially along the line 22 of FIG. I, in the direction of the arrows and showing, on an enlarged scale, the end of the mounting and positioning member, the spring clip and spring washer in plan;

FIG. 3 is a sectional view taken substantially on the line 3-3 of FIG. 2 in the direction of the arrows showing details of the adjustable mounting features;

FIG. 4 is a view looking in the direction of the arrows on line 4-4 of FIG. 3, parts being broken away to illustrate the adjustable mounting of the wheel on its mounting and positioning member;

FIG. 5 is a diagrammatic sectional view of a punch press illustrating the method of making the tubular type bearing structure; and

FIG. 6 is an enlarged, broken, developed view of the strip of sheet metal with the type embossed on it.

Referring to the drawings and particularly to FIG. 1, it will be seen that a type wheel of the class disclosed herein may be used in a telegraph printer of the type disclosed in the US. Pat. No. 3.176.069. issued Mar. 30, I965 to W. J. Zenner. As illustrated in that patent, a shaft supports a type wheel 186 for reciprocation and rotation to select a character for printing and for oscillation to effect printing. The type wheel 186 moves across a platen 271 and an inking ribbon 272 and the type wheel 186 is driven to engage the ribbon 272, for effecting printing, by a print hammer 293. In the present invention the type wheel 186 is of distinctly different construction and is mounted in a novel manner on the mounting and positioning member for the type wheel, the shaft 190.

In the embodiment of the invention disclosed herein. the portion of the type wheel 186 on which the character printing type are formed is an eight-sided substantially tubular sheet metal member 10 which could have any desired number of sides depending on the number of characters required for printing of a text. This eight-sided member 10 is formed from a single sheet of metal in the manner illustrated in FIG. 5, wherein there is shown a punch 11 having a suitable shank 12 for attaching it to the head of a punch press (not shown).

The entire sheet metal member 10 is formed in one stroke of the press by shearing the body of the member 10 from a sheet 13 of metal stock leaving scrap as indicated at I4 and 15. In this shearing operation, the punch 11 forces the member 10 into a cavity 16 in a die block 17, cutting the member 10 from the sheet 13 and forming a registering notch 18 and tab 19 (FIG. 6). Continued movement of the punch 11 into the die block 17 forces printing character forming projections 20 into the member 10 and forms the metal of the member 10 into recesses 21 in the die block 17. In this type forming operation the sheet metal is deformed beyond its elastic limit and consequently sharp, clear, character delineating ridges 22 are embossed on the sheet metal member 10.

Simultaneously with the forming of the character delineating ridges 22, the member 10 is stressed, along lines 23 transverse to its length, beyond its elastic limit. This is effected by providing sharp ridges 24 on the punch 11 in alignment with the sharply angled surfaces of the die block at the lines 23. The mating surfaces of the punch 11 and die block 17 are gently curved from the lines 23, to bend the member 10 within its elastic limit in the area marked 25, (FIG. 5), to afford a flat or relatively flat area 26 adjacent each of the printing character projections 20 and recesses 21.

When the punch 11 is retracted from the die block 17 the member 10, having been embossed with all of the character delineating ridges or type faces 22 of the type font and also having been bent beyond its elastic limit along the lines 23, will assume a configuration as shown in section in FIG. 2.

Thus, the member with the type faces or ridges 22 extending from its outer surfaces forms, in this case, the outer shell of an octagonal flat-sided substantially tubular printing member. The member 10 will have eight rows of type on its outer surface, in four levels, as illustrated in FIG. 6, which levels will be aligned by nesting the tab 19 in the notch 18.

In order to impart rigidity to the member 10 and to supply means for mounting the member on the shaft 190, four octagonally shaped reinforcing members 30 are attached to the inner surface of the member 10 by spot welds 31. As shown in FIG. 3, the reinforcing members 30 are fixed to the member 10 at approximately the vertical centers of the type character printing elements 22 by applying the spot welds at the corners formed along the lines 23. All of the reinforcing members 30 are provided with central apertures 32 of a diameter to snugly fit on the shaft 190 and at least the bottom member 30 is provided with a plurality of locating holes 33 which are evenly spaced one from the other in a circle and disposed in the area between the central aperture 32 and the periphery of the member 30.

The shaft 190 has a shouldered collar 34 fixed to it by means of a pin 35. This collar is provided with a plurality of locating holes 36 which are arranged in the same manner as the locating holes 33 in the reinforcing member 30, except that, while the holes 36 are arranged with their axes the same distance from the axis of the actuating member 190 as the holes 33 and are equally spaced one from the other, the spacing between the holes 36 is slightly smaller than the spacing between the holes 33. The locating holes 33 and 36 are of the same size, chosen to snugly fit with a locating pin 37 which is fixed in a locating ring 38 that encircles and is free to move on the actuating member 190. The locating pin 37 extends beyond the upper and lower surfaces of the locating ring 38 and may be selectively positioned in the holes 33 and 36 in the reinforcing member 30 and collar 34 to provide a very fine adjustment of the type wheel 186 with respect to the shaft 190.

Near its upper end, the shaft 190 has an annular recess 39 formed in it for receiving the projecting arms 40 of a hairpin type fastener 41, the closed end of which is bent upwardly as shown at 42. The fastener 41 is wedged between the upper surface of the recess 39 and an annular spring washer 43 which encircles the actuating member and presses the type wheel structure 186, comprising the member 10 and its reinforcing members 30, firmly onto the collar 34.

Although a specific embodiment of the invention has been shown in the drawings and described in the foregoing specification, it will be understood that the invention is not limited to the specific embodiment but is capable of modification, substitution and rearrangement without departing from the spirit of the invention.

1 claim:

1. A type wheel assemblage for a step-by-step impact printer comprising:

a unitary sheet metal type font member deformed along a series of parallel transverse lines to form a plurality of contiguous, angularly disposed face portions, each face portion having at least one type character printing element embossed therein and projecting outwardly of its outer surface, the angular relation of the face portions, one to the other, being such that said face portions form a substantially tubular sheet metal shell having a cross-sectional configuration conforming to a regular polygon;

a plurality of polygonally shaped reinforcing members, each having a periphery which conforms in size and configuration to the interior of said shell, affixed to the inner surface of said shell in alignment with the midportions of the type elements to afford a substantially tubular type font structure with the type elements arranged in rows and columns thereon, said reinforcing members each having an axial aperture for receiving a mounting and positioning member;

a mounting and positioning member projecting through said axial apertures in said reinforcing members; and

means for attaching the reinforcing members to the mounting and positioning member to mount said type font structure thereon.

2. The type wheel assemblage defined in claim 1 wherein the sheet metal member is formed from a single sheet of metal having a notch at one edge and a complementary tab at the opposite edge and is prestressed along said transverse lines at the edges of the face portions to engage the tab at said opposite end in the notch at said one end.

3. The type wheel assemblage as defined in claim 1 wherein the mounting and positioning member is a shaft, and in which the attaching means includes an annular collar fixed to the shaft, a locating ring resting on said collar, and means for compressing one of the endmost reinforcing members fixed to the sheet metal member against said ring on the collar.

4. The type wheel assemblage as defined in claim 3 wherein the compressing means includes a fastener member engaged with a surface of the shaft and'a resilient member compressed between the fastener member and the other endmost one of the reinforcing members.

5. The type wheel assemblage as defined in claim 3 wherein the annular collar and said one endmost reinforcing member each include internal locating surfaces, and wherein the locating ring has a locating member fixed to it for registration with said locating surfaces in both the annular collar and said one endmost reinforcing member.

6. The type wheel assemblage as defined in claim 5 wherein the locating surfaces in the annular collar and in the one endmost reinforcing member are the edge surfaces of holes that are arranged in circles equally spaced from the axis of the shaft, the holes in the collar are equally spaced, one from the other, by a predetermined distance, the holes in the said one endmost reinforcing member are equally spaced, one from the other, a distance slightly different from the spacing of the holes in the collar and the locating member is a pin fixed in the locating ring in position for selective registration with the holes in the collar and said one endmost reinforcing member whereby minute rotative adjustment of the printing structure with respect to its shaft may be achieved.

7. The type wheel assemblage as defined in claim 2 wherein the reinforcing members are fixed to the sheet metal member by spot welds at the interior junctures of the face portions.

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