US2919641A - Printing mechanism - Google Patents

Description

Jan. 5, 1960 F. w. PFL'EG'ER 2,919,641

PRINTING MECHANISM Filed March 7, 1957 7'/M//VG MEANS INVENTOR. 40

44 A fEg zerzik WFf/eger Armmvgx United States Patent PRINTING MECHANISM Frederick W. Pfleger, Pennsauken, N..l., assignor to Radio Corporation of America, a corporation of Delaware Application March 7, 1957, Serial No. 644,576

7 Claims. (Cl. 101-93) This invention relates to printing mechanisms, and more particularly to rotary type printers.

In some known devices, a rotating type carrier or type wheel is halted during a printing operation by means of pawls and ratchets or the like so that a hammer may subsequently strike a sheet of paper against a character on the surface of the type wheel Without the occurrence of blur. In order to achieve high speeds, it is preferable to stop the type carrier rapidly so that lost time may be minimized.

Therefore, it is an object of this invention to provide an improved printing mechanism of the rotary type which may operate at high speeds.

It is a further object of this invention to provide a novel printing mechanism which, by eliminating the need for any pawls or ratchets, is simply constructed.

In accordance with this invention, a type-carrying annular ring is rotated by a constantly rotating concentric shaft. The ring and shaft are coupled together by a resilient material, such as a spring. The annular ring is of comparatively low mass and thickness so that its moment of inertia is small. By striking the ring with a hammer, the rotating ring will halt due to the frictional force of the hammer upon the ring (although the inner shaft continues to rotate), and a character may be imprinted upon a suitable sheet. Upon release of the hammer, the ring resumes its original orientation with respect to the shaft due to the springing effect of the resilient material.

The annular ring should be as thin and as lightweight as possible. A preferred form is that of a thin, flexible nylon belt. The concentric shaft, with grooves and lands around its periphery, gives support to the flexible ring. The lands are located beneath the corresponding characters on the ring so as to give adequate support to the ring when it is struck by a hammer. The grooves on the shaft act as oil reservoirs, so that the shaft is well lubricated. By using such a printing mechanism, a hammer may strike the rotating ring and print without the occurrence of blur.

The novel features that are considered characteristic of this invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation as well as additional objects and advantages thereof will best be understood from the following description when read in connection with the accompanying drawings, in which:

Figure l is a view transverse to the axis of rotation and partly in cross-section of one embodiment of this invention utilizing a rubber block as a resilient member;

Figure 2 is a view transverse to the axis of rotation and partly in cross-section of an embodiment similar to that of Figure 1, but in modified form utilizing a spring as a resilient member;

Figure 3 is a plan view of the embodiment shown in Figure 1 or in Figure 2 illustrating a plurality of type carriers for use in practicing the invention; and

Figure 4 is a plan view of a simplified spring means J 2,919,641 Patented Jan. 5, 1960 for use with the plurality of type carriers shown in Figure 3.

With reference to Figure 1, a printing mechanism comprises a shaft 10 rotating in a clockwise direction as viewed in this figure. A circumferentially resilient member, such as a rubber block 12, is mounted in a groove in the shaft 10. The shaft It) is concentrically mounted within an annular ring 14. The ring 14 is coupled to the shaft 10 by means of a positioning member 16 placed adjacent to the resilient member, or rubber block 12. The outer surface of the annular ring 14 contains a font 18 of printing characters. The annular ring 14 has a low moment of inertia, being constructed of a thin, lightweight material, such as nylon. Preferably, the ring 14 is so thin that it is flexible and depends upon the shaft 10 for its support.

The lands 22 are located beneath the corresponding characters so as to provide a suitable backing or support for the ring 14 when a character is hit by a striking member. In grooves between each of the lands 22 are the oil reservoirs 2t) which provide adequate lubrication, decreasing friction, for reducing the moment of inertia of the printing mechanism, and hence reducing undersirable blur. An inked ribbon 24 and printing hammer 26 are suitably located a short distance away from the ring 14.

The operation of the embodiment, as shown in Figure 1, is as follows:

The shaft 10 rotates continuously, at a fixed speed, carrying with it the annular ring 14 which normally rotates at the same speed, due to the positioning member 16 coupling the ring 14 with the shaft 10. However, when it is desired to print a desired character onto a print receiving material, such as paper 28, the hammer 26 is actuated so as to strike the desired character on the annular ring 14. An imprint of the character is printed by means of the ink ribbon 24 onto the paper 28 which had been placed adjacent to the ribbon 24. The striking of the hammer 26 causes the annular ring 14 to come substantially immediately to a halt due to its negligible moment of inertia. Because the ring 14 comes to a substantially immediate halt, the blur, if any, appearing on the paper 28 is negligible. During the interval that the annular ring 14 is halted, the shaft 10 continues to rotate, causing the positioning member 16 to compress the rubber block 12. When the hammer 26 releases, the resilience of the rubber block 12 forces the positioning member 16 back to its original location so that the ring 14 and the shaft 10 are oriented with respect to each other as they were initially.

With reference to Figure 2, there is shown a similar device operating in a similar manner. The shaft 10 rotates, as shown, in a clockwise direction. A spring 30 is affixed to a sectorial cavity 32 in the shaft 10. The annular ring 14 has a protuberance 16 projecting inwardly which acts as a positioning member. When the ring 14 is halted by the action of a print hammer, the positioning member 16 biases the spring 361, so that, when the annular ring 14 is released, the spring 30 urges the ring 14 in proper orientation with the shaft 10. Although no oil reservoirs are illustrated in Figure 2, it is understood that, for excellent performance, suitable lubrication should be provided between the ring and shaft. Oil reservoirs, as shown in Figure .l, or other suitable lubricating means may be used.

With reference to Figure 3, there are shown a plurality of annular rings 14 mounted in suitable fashion for use ice as a multiple character printer, such as a line-at-a-time suitable means, such as by gears 36. Coded information for printing an entire line may be placed into a control unit 38 for operating the hammers 26 so that, upon one revolution of the shaft 10, a line is printed. Each character appearing on the font 13 of an annular ring 14 is printed when that character approaches its respective hammer 26. Any suitable controlling mechanism may be used. To further illustrate the invention, as shown in Figure 3, assume that it is desired to print a message reading abcabcabca. The information for this message is stored in the control unit. As the shaft 10 rotates, so that the as appear under the hammers 26, the first, fourth, seventh and tenth hammers are actuated, causin as to be printed onto the paper at the first, fourth, seventh and tenth positions in a line. The shaft continues rotation, and when bs appear under the harnmers, the second, fifth, and eighth hammers are actuated. Similarly, at a short interval, the third, sixth and ninth hammers cause cs to be imprinted onto the paper 28. The printed message then reads: abcabcabca. During one revolution of the shaft, one line is imprinted on a sheet of paper 23. During the next revolution, information regarding the next line may be fed into the control unit 38 and the paper 28 may be advanced. During the following revolution, 21 second line may be printed and again during the next revolution, new information may be fed into the control unit 38. The cycle may be repeated for as many times as desired.

There is shown, in Figure 4, a suitable spring means 40 for use in the printing mechanism shown in Figure 3. The spring means 40 is constructed of one piece of spring steel, so cut so that ten fingers 42 extend from a common handle 44. Each finger is associated with a corresponding annular ring 14. Such a unitary spring means is easily constructed.

The annular ring 14 may be constructed of a thin lightweight material, such as nylon. However, the annular ring 14 may also be constructed of other suitable materials, especially those which provide a thin ring of relatively low moment of inertia. Since the moment of inertia of an annular cylinder is /21i-5h(r r where 5 is the density, h is the width, and r and r are the outer and inner radii, respectively, of the annular cylinder, it is preferable to use a lightweight material. However, a very thin steel ring may be used. The steel ring may be made extremely thin, tending to compensate for the greater density of steel over nylon, and the ring still may have the requisite mechanical properties.

It will be further understood, of course, that the invention is not limited to the particular embodiment shown and described, but is capable of various modifications and further embodiments without departing from the scope of the appended claims.

What is claimed is:

1. A printing mechanism comprising an annular ring having a low moment of inertia adapted to hold type, said ring being so thin as to be flexible, a drive shaft adapted to be continuously rotated within and to support said ring, said shaft having friction-reducing oil reservoirs about the periphery of said shaft, and a circumferentially resilient member coupling said shaft to said ring.

2. A printing wheel comprising a ring adapted to hold type, a drive shaft adapted to be continuously rotated within and supporting said ring, said shaft having friction-reducing oil reservoirs about the periphery of said shaft, a circumferentially resilient member coupling said shaft to said ring, and means interrupting the rotation of said ring, when said shaft is continuously rotating, by printing a character on a print receiving material.

3. A printing mechanism for printing on a print-receiving medium and comprising a thin, flexible, annular ring carrying a plurality of type faces, a drive shaft, means for continuously rotating said drive shaft within, concentric with, and in supporting relationship to said ring, a. circumferentially resilient coupling between said ring and said shaft for rotatably driving said ring by rotating said drive shaft, a print hammer, and means for impelling said hammer against any said type face with said printing medium interposed between said type face and mer, said type face being backed and sup-ported by said shaft, said medium thereby receiving a printing impression, said circumferentially resilient coupling affording a momentary stop of said ring without stopping shaft when any said impression is thus made and a ng said ring to resume its initial position relative to said shaft before the next succeeding impression is made.

4. A printing mechanism as claimed in claim 3, said coupling including an inwardly projecting stop member carried by said ring.

5. A printing mechanism as claimed in claim 3, said coupling comprising a spring, said ring carrying an inwardly projecting stop member against which said spring is biased for providing the said drive coupling.

6. A printing mechanism as claimed in claim 3, said coupling comprising a rubber block, said shaft having a groove in which said block is mounted, and an inwardly projecting stop member carried by said ring against which said block bears for providing said coupling.

7. A printing mechanism for printing on a print-receiving medium and comprising a plurality of thin, flexible, annular rings each carrying a plurality of type faces, a drive shaft, means for continuously rotating said drive shaft within and concentric to said rings, said shaft carrying said rings side-by-side, a plurality of circumferentially resilient couplings respectively between said rings and said shaft, a plurality of print hammers corresponding respectively to said print wheels, and means for impelling selected hammers against any selected type face with said printing medium interposed between said type face and. said hammer, said type face being supported and backed by said shaft, said printing medium thereby receiving a printing impression, said circumferentially resilient couplings affording driving couplings between said drive shaft and said respective rings for driving the rings concentrically for rotation with said shaft and affording a momentary stop of the rotation of any shaft when a said impression is made by the corresponding print hammer and causing the corresponding ring to assume its initial position in relation to said shaft before the next succeeding type face of that ring is in position for effecting an impression.

References fitted in the file of this patent UNITED STATES PATENTS 1,606,190 Sharp Nov. 9, 1926 1,646,576 Castan Oct. 25, 1927 1,675,969 Bull July 3, 1928 2,036,027 Ecker Mar. 31, 1936 2,157,035 Torkelson May 2, 1939 2,211,794 Rohland Aug. 20, 1940 2,468,427 Cheeseman Apr. 26, 1949 2,603,153 Warren July 15, 1952 2,631,535 Mumma Mar. 17, 1953 2,737,883 Crawford Mar. 13, 1956 2,787,952 Roche Apr. 9, 1957 2,805,620 Rosen Sept. 10, 1957

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