US3823667A

US3823667A - Force adjustment in impact printers

Info

Publication number: US3823667A
Application number: US00268237A
Authority: US
Inventors: E Babler
Original assignee: Teletype Corp
Current assignee: AT&T Teletype Corp
Priority date: 1972-07-03
Filing date: 1972-07-03
Publication date: 1974-07-16
Anticipated expiration: 1991-07-16
Also published as: GB1437983A; JPS49100929A; CA1016810A; DE2333528A1; IT989705B; GB1437984A

Abstract

A plurality of self-restoring equally spaced apart print hammers selectively are driven lineally toward a printing position by continuously rotating impellers having equiangularly spaced radial impelling elements. Each impeller is effective through the agency of a rockable interponent, which is selectively elevated into the path of associated impelling elements upon latching of the armature of an electromagnet, for transmitting impeller force to a corresponding print hammer. An elastomeric bumper, disposed in the path of the print hammers, dampens printing force on dies, which are conveyed past said hammers for printing, in equally spaced relationship different from the spacing of said hammers. Each die, when at a printing station, is aligned with a print hammer but spaced therefrom a distance inversely proportional to its printing area for producing copy of uniform intensity.

Description

United States Patent [191 Babler July 16, 1974 I FORCE ADJUSTMENT IN IMPACT PRINTERS [75] Inventor: Egon S. Babler, Northbrook, Ill. [73] Assignee: Teletype Corporation, Skokie, Ill.

[22] Filed: July 3, 1972 -[2l] Appl. No.: 268,237

[52] US. Cl. .101/93 C, 101/111 [51] Int. Cl B41j9/l2 [58] Field of Search 101/93 C, 111, 368;

[56] References Cited UNITED STATES PATENTS 2,796,966 6/1957 Toeppen; 197/17 3,144,821 8/1964 Drejza 101/93 C 3,172,353 3/1965 101/93 C 3,266,419 8/1966 Erpel et a1. 1'01/93 C 3,308,749 3/1967 Dowd 101/368 X 3,386,376 6/1968 Mutz et al lOl/93 C 3,451,335 6/1969 Cunningham 101/111 X 3,504,623 4/1970 Staller 101/93 C 3,587,456 6/1971 Jaensch l0l/93 C 3,742,848 7/1973 l-luntoon et a1 -10l/l 11 X OTHER PUBLICATIONS Bear et a1., Printl-Iammer Impact Control Mechanism," IBM Technical Disclosure Bulletin, Vol. 5, No. 11, Apr., 1963, pp. 27-29.

Primary Examiner-Robert E. Pulfrey Assistant Examiner-Edward M. Coven Attorney, Agent, or FirmSherman P. Appel; John L. Landis [57] ABSTRACT A plurality of self-restoring equally spaced apart print hammers selectively are driven lineally toward a-printing position by continuously rotating impellers having equiangularly spaced radial impelling elements. Each impeller is effective through the agency of a rockable interponent, which is selectively elevated into the path 27 Claims, 4 Drawing Figures PATENTEnJuu 61974 BACKGROUND OF THE INVENTION print hammers which are actuated by a logic system responsive to data to be reproduced.

Ideally suited for developing impact forces in said class of printers, because of the high level of timing accuracy for print hammer control, are impelling means of the type disclosed in US. Pat. No. 2,927,960, issued to W. P. Byrnes, Mar. 8, 1960. In my copending application Ser. No. 286,238, filed contemporaneously herewith, there is shown and described an improvement for adapting the disclosure of said patent for high speed printing.

Heretofore unknown for printers with such impelling means areymechanisms for varying the printing forces .such that image density is substantially uniform from one print-out period to another, regardless of the: (l) number of copies (within limits) simultaneously printed during eachprint-out period and (2) variation in the .masses'of printing dies within a font.

It is an object of the present invention to provide an improved impact printer. v 7 I It is another object of. the invention inan impact printer to adjust the printing forces in accordance with the number of plies simultaneously being printed.

It is afurther obje ct of the-invention in an impact printer to adjust printing forces according to the masse of the printing dies.

SUMMARY OF THE INVENTION Toattain the foregoing, and other objects of the invention which'will become apparent from the ensuing FIG. 2' is a vertical sectional view of said printer according to the line 22 of FIG. I;

FIG. 3 is an enlarged elevational view of a print hammer for said printer; and

FIG. 4 is a detailed view taken in a horizontal plane according to the line 4-4 of FIG. 2, parts having been omitted for the purpose of illustration.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIG. 1 of the drawings, the impact printer shown is generally designated 10. It has a pair of spaced

apart pulleys

12 and 14 about which an endless carrier 16 is trained for translocating a plurality of pallets 18 by movement in a circuitous path. A plurality of dies 17 (FIG. 2) are carried on the front faces of the pallets, the latter being uniformly dimensioned and uniformlyand equally spaced apart axially of the carrier. When the dies comprise alphanumeric characters, two or more successive fonts axially of carrier 16 may enable longer line output.

Carrier 16 and pallets 18, together with their mountings may be substantially as shown and described in the copending application of Francis E; I-Iuntoon and James F. Kearney, Ser. No. 208,198, filed Dec. 15, 1971, and assigned to the assignee of the present application, now Pat.- No. 3,742,848, granted July 3, 1973.

In accordance with said last copending application, the

plane in which parallel axes of pulleys l2 and 14 are disposed and the vertical section 20 of web 22 on which printing is about to occur are orthogonally disposed. Such arrangement generates a loop in the carrier with an upper or printing course 21 and a lower or return course 23 which are disposed in a plane which is substantially parallel to web section 20.

In the exemplary printer 10,.pulley 12 is an idler I sheave while pulley 14 is a drive sheave secured to a shaft 24, Driving torque continuously is transmitted to saidj shaft from an operating prime mover means,

- direction indicated by arrow 31 during printer operadetailed descriptiomin a printer which has means for selectively driving a print hammer in a lineal path between a non-printing position and a printing position. A carrier and the hammer are relatively movable for successively aligning carrier supported dies with-the hammer for printing. The impact of the hammer is adjusted according to the depth of material against which the impact is applied, the. adjustment resulting from means for damping the driving force and disposed in the path of the hammer.

From another aspect, the objects of the invention are attained in an impact printer in which printing is effected by aligning a succession of dies with impact means. In such printer. means are provided for varying the printing force applied to the dies at the time of printing according to their printing areas.

BRIEF DESCRIPTION OF THE DRAWINGS In the ensuing detailed description of the drawings, reference is had to the accompanying drawings on which:

'FIG. 1 is a perspective view of an impact printer embodying one form of the invention, parts being broken away and parts omittedfor the purpose of illustration;

herein shown as a motor 26, through a drive train generally designated 28. The latter hereinincludes an impeller shaft 30. This shaft is continuously driven in'the tion.

A segment 32 of ribbon 34 is disposed in'a plane substantially parallel to carrier course 21 between and spaced slightly from face 36 of web section 20 and the 1 pallets 18 supported from said last course. The ribbon is trained abouta plurality of ribbon guides 38 which are spaced apart such that the ribbon assumes a generally rectangular configuration in a horizontal plane. Opposed end'portions of the ribbon are secured to a pair of adjoining

ribbon spools

40 and 42 which alter nately function for; ribbon supply and accumulation. They alternately are driven in opposite angular directions, by a spool control mechanism 44, the details of construction of which form no part of the present invention. Mechanism 44 is connected to motor 26 through a pulley wheel 46, disposed in a common plane 3 vention. Thereupon, operating means, being a drive train generally designated 54, advances web 22, in the direction shown by arrow 56, a line at a time such advancement results from incremental rotation of a worm gear 58 for driving a pulley belt 60 intermittently angularly to move a cylindrical roller 62. Roller 62 is disposed'transversely of and adjacent to the path of web movement for frictionally engaging web 22 and incooperation with other components (not shown), intermittedly drawing said web from its supply source (not shown) about a guiding cylinder 64, as said web is advanced.

Impelling means comprises an array of radially symmetrical impellers 66 (only representative ones of which are shown in FIG. 1). The impelling means herein are substantially as shown and described in my aforesaid copending applications Ser. No. 268,238 and in another application Ser. No. 268,236, also filed contemporaneously herewith. Accordingly, each impeller is comprised of a plurality of raidal, equiangularly spaced arms or impelling elements 68, the impellers being concentrically secured to shaft 30 for rotation therewith in the direction shown by arrow 70 (FIG. 2),

in the exemplary embodimentQTheimpellers are axially or horizontally spaced such that each is disposed in substantially horizontal alignment with a printing station on an imaginary line extending horizontally across web section 20. Opposed end portions of the shaft 30 are journalled in spaced apart vertical side members 72 '(only one is shown'in FIG. 2) of the frame or chassis.

74 of printer 10.

Impacter means for printing comprise a plurality of hammers 76 (only some of which are shown in FIG. 1) having enlarged printing heads 77 at their inner ends,

' the heads 77 being-disposed behind back face 78 (FIG.

2) of web section 20. As shown in FIG. 4, each hammer is aligned with the others in a horizontal array parallel to the alignment of impellers 66 for linear reciprocating movement along a horizontal printing axis X, toward and away from an associated type die 17. As illustrated in FIGS. 3 and 4, the printing axes X refer to horizontal axes running longitudinally through the centers of the hammers 76, from left to right in those FIGS, and

through the center of the type dies 17 when aligned witha hammer for printing, as shown in FIG. 3 and as shown for the first, third and fifth dies 17 from the top in FIG. 4. Each hammer also is aligned with, though spaced'from, and disposed out of the path of movement of an associated impeller by which it can be selectively driven in a lineal path along printing axis X, perpendicularly to web section 20, between a normal or nonprinting position (FIG. 1) and a printing position (dashed line of FIG. 4) in which the hammer head 77 engages against said back face 78 (FIG. 2).

The dies-17 on pallets 18 in course 21 and hammers v76 are disposed at a common horizontal level; and said pallets and their dies when translocated move in a path parallel to the hammer array for printing. Thereby,

each-palletl8 and-groups thereof can be moved successively into printing positions in horizontalalignment with successive hammers 76 and groups thereof, along printing axes X. The force generated by each impeller 66 for urging web section 20, ribbon'segment 32 and any aligned dies 17 into contact is of sufficient magnitude for printing by forming an image of each such die on web face 78. In the exemplary embodiment of the invention, the hammersare associated with and reciprocatively arranged in chassis 74 by means and in the manner disclosed in said copending application Ser. No. 268,238. As described in that application, and as shown in this application each hammer 76 is elongated in the direction of its line of flight (axis X), and includes a rectangular body section 176, having the head section 77 formed at the inner or right end, as viewed in FIGs. 3 and 4, and having a relatively long, relatively thin, rectangular tail section 177 formed at the outer or left-end of the body section 176, and extending toward the associated impeller 66, as illustrated in FIG. 2. The outer or left end 178 of the tail section 177 is flattened as shown in FIGS. 1 and 4 for driving by one of the impeller arms 68 to propel the hammer 76, as will be explained hereafter. As. illustrated in FIGS. 3 and 4, the

hammer sections

77, 176 and 177 will extend in a straight horizontal line centered on the printing axis X.

, are slideably mounted in the chambers 182 against a transverse bearing bar 183 mounted on the wall 180'. A chassis plate 184 has portions disposed in bearing engagement with hammers76 and extends in a horizontal plane as a roof or cover for chamber 182. A slotted flange (not shown) depends from the plate 184 to provide horizontally aligned verticalguide slots between which the hammers are reciprocative, as shown and described in-the copendingapplication Ser. No. 268,238. These guide members in the frame serve to mount and guide the hammers 76 for precise linear reciprocation along the printing axes X, to print characters as will be described hereafter.

A horizontal bumper in the form of an elongated rod is disposed parallel to shaft 30 along a horizontal axis Y (FIGS. 1 and 4) perpendicular tohammer axes X, and has opposed ends secured in the chassis sides 72. Said rod extends through horizontally aligned holes or slots 82 in the hammers 76 for limiting horizontal hammer movementalong axis X, as illustrated in FIGS.

2 and 3, theslots are generally rectangular as viewed in the plane of FIGS. 2 and 3, and extend through the body section section 176 of each hammer in the' direction of bumper axis Y. (The bumper axis Y refers to the perpendicular horizontal aixs running through the center of the bumper 80, from top to bottom in the layout of FIG. 4, or from left toright in FIG. 1.)

As shown in FIGS. 3 and 4, the bumper 80 has a portion received within'the slot 82 of each hammer 76 in the row, and the height of the-bumper 80 (from top to bottom in FIG. 3) is less than that of the slots 82 so that the hammers 76 may reciprocate with respect to the bumper along theprinting axis X. However, the portion of the bumper 80 within each slot 82 is enclosed on all sides by walls of the slot 82, as shown in FIGS. 1 and 3, the slot 82 and body section 176 of the hammer being symmetrical above and below axis X, as viewed in the vertical plane of FIG. 3, so that the bumper is centered on axis X as is theslot 82. t A leaf spring 84- (FIG. 2) of general vertical orientation and associated with each hammer 76, is included in hammer driving means. It has a lower end portion which is rigidly secured to a front chassis plate 86 and an upper end portion engaged in a downwardly opening Each hammer head 77 is also formed with an upwardly opening slot 89 (FIGS. 3 and '4) aligned with the slot 88 and of the same shape so that the hammer 76 is symmetrical above and below axis X, as viewed in FIG. 3.

Each spring 84 has a slightly tensioned condition (FIG.

' 2) during which its hammer is in its rearward or most remote non-printing position, and a most tensioned condition (not shown) during printing for urging or restoring its hammer to non-printing position.

' Each impeller 66 is adapted to move a printingly associated and aligned hammer 76 through the agency of an interponent 90. In the preferred embodiment of the invention, printing is effected and the assemblies of the interponents as well as the other parts of printer 10, including means for controlling and liberating the interponents are, as shown and described in said last named copending application. In accordance therewith, the interponents are disposed in general horizontal alignment and each has: (I) a first'or upper position in which it is in a projected condition, with its upper free end portion disposed inthe path of movement of associated impelling elements 68 for transmitting force from its impeller 66 to an aligned hammer 76 in conse- -slot 88in the printing head 77 of each hammer 76.

As shown in said I-Iuntoon-Kearney patent pallets 18 are mounted on the inner ends of shanks 100; and the shanks are disposed in a horizontal plane and are removably mounted in carrier 16, extending transverely through its hammer proximate side 102 and hammer distal side 104. In accordance with the present invention, for adjusting the impact of each hammer 76 upon printing according to the depth of material against which the impact is applied, damping means is disposed in the path of hammer movement. Herein, said last means comprises a resilient or a viscous damper which may be an elastomer from which bumper 80 is fabricated. Thereby, the hammers and said damping means are arranged for relative movement. The disposition of the bumper in the hammer slot 82 is such that the bumper limits movement of each hammer in each of opposite directions along printing axis X by engagement with front and rear sides 106 and 108 (FIG. 3) of slots 82. In the initial or nonprinting position of the hammer 76 ,the leaf spring 84 biases the'hammer to the left in FIGS. 3 and 4 to a rest position where the inner or front sidewall 106 of the slot 82 engages an inner or front wall 1090f the bumper, as shown in FIGs. 2 and. 3.

quence of which printing occurs, and (2) a lower, nonprinting, 'or second position in which said interponent has fallen and is removed from the impeller path.

As shown and described in said application Ser. No. 268,238, each interponent 90 intermittently is controlled by an electromagnet assembly comprised of a magnetically latchable armature 92 and an electromagnet 94 (FIG. 2). Any suitable logic (not shown and formingno part of the present invention) which may be conventional may be employed for energizing each of said electromagnets 94 selectively. In consequence of energization of any electromagnet its armature will be rocked, magnetomotively, against the restoring bias of its spring96 clockwise from its position shown (FIG. 2)

j to a latched position (not shown).

Correspondingly, an affected interponent will be thrust upwardly (from its FIG. 2 position) into its first position or projected condition (not shown) between a pair of adjoining impelling elements 68 against the low ering bias of an associatedspring 98 which becomes tensioned upon upward movement of its interponent. Ensuingly, the upwardly thrust interponent will be en: gaged by a circuitously traveling impelling element 68 and rocked into engagement with an' associated hammer 76 to effect momentum transfer and translation of impeller torque into a lineal force for printing. In the exemplary printer 10, both momentum transfer and restoration of an interponent to its second position (FIG. 2) following momentum transfer, as well as the conditioning of interpo nents90 for repeat cycles are as shown and described in said last named copending application.

In the printer 10, as illustrated (FIG. 4), the hammers 76 are equally spaced apart and the pallets 18 in a font in course21 are also equally spaced apart. However, the spacing between the centers of thehammers is not the same as the spacing between the centers of the pallets. Their spacing, as well as their dimensions, mode and sequence of operations, and printing with printer are as shown and described in said copending application Ser. Nos. 268,238 and 268,236

As best illustrated in FIGS. 2 and 3, the slot 82 is elongated along the X axis, compared with the width of the bumper (from left to right in FIG. 3), so that a preset clearance or distance 110 is provided between the slot and bumper along the axis X of hammer flight. More specifically, the distance 110 between the rear wall 112 of bumper 80 and each rear side 108 of a slot 82, when its hammer 76 is in its normal position (FIG.

3) is such that, for the thickest number of plies of sheets of paper intended to be accommodated in the horizontal span 113, between the end face 114 of hammer head 77 and a die 17 aligned therewith for printing, side 108 will just come into engagement with wall 113, when said hammer face reaches printing position. Accordingly, to the extent that the thickness of the paper mass in span 112 is reduced from such maximum, each hammer 76 will move further to the right (relative to FIGS. 2and 3), compressing the bumper 80 correspondingly, to reach printing position shown in phantomlines for the second hammer 76 from the top in FIG. 4. By fabricating bumper 80 of polyurethane material having a du'rometer Shore hardness of A,

Additionally, the bumper 80 is proportioned such that it serves to absorb rebound energy of the hammers 76 following printing as they are restored to normal positions (FIG. 1). As each hammer 76 rebounds to the left in FIGs. 3 and 4 from a printing operation, the inner or right side wall 106 of the slot 82 engages the inner or right side wall of the bumper 80 to absorb and dampen rebound energy, and thus facilitatereturn of the hammer 76 to the initial position resting against the bumper 80, by the biasing spring 84.

For adjusting the spacing of hammers 76 and pallets 18, that is, for setting the distance across span 113, the pallets are adjustable toward and away from thehammers. To that end a back-up bar or stop member 116 is supported from a frame or chassis member 18 along side 104 of carrier course 21. The back-up bar is engaged by the outer ends of shanks in said upper course and is adjustable in a horizontal plane toward and-away from carrier 16 within the limits of a slot 120 in said back-up bar. Means for releaseably securing'the back-up bar in adjusted positions may comprise a threaded pin 122 passed through slot 120 from member 118 for holding a clamping nut 124 against the back-up bar.

From another aspect of the invention, the impact upon printing is adjusted according to the force transfer areas or sizes of the printing surfaces of the printing dies. This adjustment is for minimizing variation in copy intensity due to variation in the size of characters of the dies. For that purpose, the lengths of shanks 100 are varied according to the sizes of the printing surfaces of dies 17. If it is impractical to vary the. lengths according to the size of the printing surface of each die, the variation may be according to sizes within selected ranges. Herein, three

pallet groups

18A, 18B, and 18C are shown (FIG. 4). EAch group has a range of die sizes different from the size ranges of the others. Pallets 18 having dies whose sizes orprinting areas are within the smallest range have the shortest shanks 100A. In an alphanumeric font, punctuation marks such as a period, and a colon belong in this last-named range. Dies whose printing areas are within the greatest size range have the longest shanks 100C. Examples of alphanumeric characters in this last named range are capitals M and W. Dies within the intermediate size range, such as many lowercase letters, have shanks 1008 of intermediate length.

Accordingly, a hammer 76 which is impelled toward a pallet carried on a shank 100A will travel the greatest distance for printing. Such hammer will compact the greatest damping mass in bumper 80. Consequently,

when it strikes for printing, its impact force will be less than the impact force when printing with a die on a pallet carried on either a shank 1008 or 100C; and such force will be dissipated over an area in the smallest range. On the other hand, a hammer printing with a die on a'shank 100C will travel the least distance to printing position. Such hammer encounters less damping mass in bumper 80 before reaching printing position that a hammer printing with a die carried on either a shank 100A or 1008. Such hammer will have the greatest energy on impact; however, such force will be dissipated over a printing surface in the greatest range.

7 As many modifications in the described construction could be conceived, and-as many widely different embodiments could bemade without departing from the spirit and scope of the claims, it is intended that all matter contained in the accompanying specification shall be considered as illustrative only and not in a limiting creasing the printing impact of said hammer as the distance ofhammer movement along the lineal path increases comprising:

a slot, having a front'and a rear side, formed in the 6 hammer; and means, disposed in and completely surrounded by the slot and engageable with the rear side of the slot as the hammer is driven in the lineal path toward the printing position, for damping the printing impact of the hammer so that the printing impact decreases as the distance of hammer movement along the lineal path increases and for absorbing rebound energy by engagement with said front side of the slot upon hammer movement to a non-printing position following printing.

2. A combination according to claim 1 characterized by means for adjusting the spacing of said hammer and an aligned die.

3. A combination according to claim 2 characterized by means for moving said carrier in a circuitous path, and means for adjusting said dies transversely of said carrier toward and away from said hammer.

4. A combination according to claim 3 wherein said carrier has a hammer proximate side and a hammer distal side, and said adjusting means comprises an adjustable stop fixed adjacent said carrier at said distal side for limiting the adjustment of said dies on said carrier.

5. A combination accoding to claim 1 characterized means for moving said carrier longitudinally past said hammer to successively align carrier supported dies with said hammer for printing, said carrier having hammer-distal and hammer proximate sides;

a plurality of pallets, transverse to and slidably supported by the carrier and having a first end adjacent the hammer proximate side of the carrier and a second end adjacent the hammer distal side of the carrier, the dies being secured to the first end and the spacing between the dies and the hammer being adjustable by sliding the pallets transversely of the carrier; and

a stop member, releasably secured parallel to the carrier along the hammer distal side thereof, for engaging the second end portions of the pallets to restrain the pallets from sliding transversely of the carrier and maintain the spacing of the dies and the hammer during printing.

6. A combination according to claim 1, includingv means for spacing said dies, when aligned for printing,

varying distances from said hammer.

7. A'combination according to claim 6 wherein said dies comprise a plurality of groups of different lengths, and the Spacing means includes meansfor spacing each group from said carrier a distance different from the spacing of any other group.

8. A combination according to claim 6 wherein each die, when aligned for printing, is spaced from said hammer a distanceinversely proportional to the printing surface area of the character on each die to be printed.

9. In a printer of the type wherein printing is effected by driving an impacting means toward a selected one of a plurality of dies, each die having a printing surface area, a mechanism for increasing the impact force of the-impacting means on the selected die as the printing surface area of the selected die increases comprising:

a carrier spaced from the impacting means and arranged for a relative movement therewith; a plurality of die shanks mounted in and extending from the carrier for supporting the plurality of dies, the length of the die shanks being variable and set in accordance with the printing surface area of the die carried on each die shank; and

means for decreasing the distance between the impacting means and the selected die as the printing surface area of the selected die increases so that the impact force on the selected die is increased as the printing surface area of the selected die increases.

10. In a printer of the type including means means for propelling a print hammer toward a selected one of a number of type dies to effect a printing operation, and means, engageable with a portion of the hammer as the hammer is propelled toward a type die, for damping the velocity of the print hammer prior to impact with the type die to absorb some of the hammer energy prior to printing, the improvement wherein:

the propelling means is arranged for propelling the hammer toward the type die with the same velocity regardless of the type character to be printed; and

11. A printer as recited in claim 10, wherein: the

means for propelling includes means for initially positioning the hammer in the same position prior to propelling,regardless of the type character to be printed;

and

the means for damping includes a resilient bumper mounted in the printer for engaging a portion of the hammer prior to printing impact so as to absorb hammer energy and thus decelerate the hammer prior to printing, and means for setting the distance traveled by the hammer after striking the bumper and before impact with the type die in accordance with the type face area, so that the hammer travels the least distance before impact with a die of the largest area, and travels greater distances before impacting with dies of smaller area. l 12. A printer as recited in claim 11,;wherein th damping means includes means for setting the-distance between the type dies and the bumper in accordance with type face area so that the dies with the smallest printing area are positioned furthest from the bumper inthe printing position.

13. A printer as recited in claim 12, whereinthe type dies are formed at the inner ends of type support members, and further comprising: i

a continuously traveling endless carrier mounted in the printer for advancement past the hammer, and carrying the type members so that the type dies face the hammer and continuously travel past the hammer in alignment therewith for printing; and a fixed back-up member mounted in the printer so that portions of the type support members travel along and engage the back-up member as they travel past the hammer, the type support members being formed of different lengths in accordance with type face area, so that the die faces are variably spaced from the bumper as they advance into the printing position aligned with the hammer. 14. A printer as recited in calim 13:

10 wherein the type members comprise type pallets having elongated'shanks with the type diesformed at inner ends thereof. the shanks comprising the type support members and being mounted in the endless carrier for advancement past the hammer so that the type dies face the hammer; wherein the back-upmember comprises a fixed backup bar mounted parallel to the bumper and engaging the outer ends of the shanks; and

wherein the pallet shanks are made in different lengths in accordance withthe type face area of the particular die carried by the pallet.

15. A printer as recited in claim 10, wherein the propelling means comprises:

means for mounting the hammer for free linear reciprocating movement along a line of flight toward and away from a type die in printing position, so that an inner printing end of the hammer faces the type die and an outer end extends away from the type die along the line of flight;

means for initially biasing the hammer to a fixed initial rest position spaced from the type die; in which the hammer occupies the same initial postion regardless of the character to be printed; and

means for striking the inner end of the hammer when it is desired to print a character, with a force sufficient to propel the hammer toward the type die to print the character. I 16. A printer as recited in claim 15, further comprising; v

an endless carrier for the type dies; means for mounting a font of type dies on the carrier for continuous movement past the line of flight and in intermittent momentary alignnment with the inner end of the hammer; and

means for positioning the type dies on the carrier so that the faces of the dies are spaced variable distancesfrom the hammer in the initial position, the spacing being set in accordance with the printing surface area of each die in the font so that those dies with the largest area are positioned closest to the hammer and those with the smallest area are spaced furthest from the hammer.

17. In combination with a teleprinter. of the type having a chassis, a resilient bumper mounted in the chassis along an axis Y, and a print hammer reciprocable along a printing axis X to engage a type member to print a character and arranged so that a portion of the print hammer strikes the bumper to dampen the hammer energy prior to impact with the type member, an improved hammer assembly characterizedby:

the hammer having a slot extending therethrough parallel to the Y axis and centered on the printing aixs X, the hammer being mounted on the bumper so that portions of the bumper extend through the slot and are centered on the printing axis X, the slot being formed so that the portions of the bumper within the slot are enclosed on all sides by walls of the slot and the hammer slot reciprocates on the bumperalong axis X as the hammer travels to and a from theprinting position, the slot being elongated with respect to the bumper along the X axis so that front and rear walls of the slot permit a predetermined length of reciprocation of the hammer with respect to the bumper. 18. A teleprinter assembly as recited in claim 17, further comprising:

means for biasing the hammer to an initial nonprinting position where the front wall of the slot engages and is stopped by a front wall of the bumper, the bumper having resilient front and rear walls engageable alternately with the front and rear walls of the slot. 19. A teleprinter as recited in claim 17, wherein the hammer rebounds after printing and wherein the front wall of the slot strikes the front wall of the bumper on rebound to dampenthe hammer rebound energy, the bumper having resiliant front and rear walls engageable alternately with the front and rear walls of the slot.

20..A teleprinter as recited in claim 17, further comprising: 7

means for mounting the hammer in the chassis for linear reciprocating movement along the printing axis X, axis X being a linear axis perpendicular to the bumper axis Y and passing through the center of the bumper. 21. A teleprinter assembly as recited in claim 20, wherein the hammer is symmetrical about the axis X in a plane through the X axis perpendicular to the Y axis.

22. A teleprinter assembly as recited in claim 21, further comprising:

means for biasing the hammer to an initial nonprinting position where the front wall of the 'slot engages and is stopped by a front wall of the bumper, the bumper having resilient front and rear walls engageable alterantely with the front and rear wallsof the slot; and 1 wh'ereinthe front wall of the slot strikes the front wall of the bumper as the hammer rebounds after printing, to dampen the hammerrebound energy.

23. In a teleprinter assembly as recited in claim 17,

of the type wherein the print hammer is propelled toward a slected one of a number of type dies to effect a printing operation, the improvement further characterized by:

means for propelling the hammer toward the type die with the same initial velocity regardless of the type character to be printed; the burnper being positioned sothat the rear wall of the slot engages the rear wall of the bumper prior to printing impact so as to absorb hammer energy and thus decelerate the hammer prior to printing; and

v means for setting the distance traveled by the hammer after striking the bumper and before impact with the type die. in accordance with the type face area, so that the hammer travels the least distance before impact with a die of the largest area, and travels greater distances before impacting with dies of amaller area.

24. A teleprinter assembly as recited in claim 17, further comprising: I

means for mounting the hammer in the chassis for free linear reciprocating movement along the printing axis X toward and away from a type member in printing position aligned with the hammer along axis X, so that an inner printing end of the hammer faces the type die and an outer end extends away from the type die along the axis X;

means for biasing the hammer to a fixed initial rest position spaced from the type member, in which the front wall of the slot engages and is stopped by the front wall of the bumper; and

means for striking the inner end of the hammer when it is desiredto print a character, with a force sufficient to propel the hammer toward the type die so that the rear wall of the slot engages the rear wall of the bumper to dampen the hammer velocity but so that the hammer continues moving into engagement with the type member to print a character.

25. A teleprinter assembly as recited in claim 24,

wherein the means for striking comprises:

a constantly rotating impeller wheel mounted parallel to the hammer along an axis parallel to the bumper axis Y, the impeller wheel having projections. that rotate past the outer end of the hammer out of engagement therewith; and

an interponent selectively insertable between an oncoming projection of the impeller wheel and the inner end of ,thehammer so that the projection strikes the interponent and forces it aganist the outer end of the hammer to propel the hammer linearly along the printing axis.

26. A teleprinter assembly as recited in'claim 17, wherein the hammer comprises: I

an elongated body section extending linearly along and centered on the X axis, the slot being formed along a portion of the body section;

an enlarged head section at-the inner end of the body section and extending therefrom along the X axis toward a type member to be printed, the body section being relatively small in cross section compared'to the head section; and i an elongated tail section at the outer end of the body section and extending therefrom along the axis X away from the type member, the tail section being relatively small in cross section compared to the head section.

27.'ln combination with a teleprinter of the type having a print hammerlinearly reciprocable along a printing axis X to engage a type member to print a character and arranged so that a portion of the print hammer strikes a resilient bumper to dampen hammer energy prior to impact with the type member, an improved hammer assembly comprising: i an elongated body section extending linearly alon and centered on the X axis, the body section having a slot therethrough centered on and perpendicular to the X axis, in which the, bumper is received so that the hammer can reciprocate with respect to the bumper, the slot having a rear wall which strikes the bumper to dampen the hammer energy;

away from the type'member, the tail section being relatively small in cross section compared to the head section.

Claims

1. In a printer having means for selectively driving a print hammer for movement in a lineal path between a non-printing position and a printing position, and a carrier arranged with said hammer for relative movement to successively align carrier supported dies with said hammer for printing by impact with force generated against an aligned die by said hammer, means for decreasing the printing impact of said hammer as the distance of hammer movement along the lineal path increases comprising: a slot, having a front and a rear side, formed in the hammer; and means, disposed in and completely surrounded by the slot and engageable with the rear side of the slot as the hammer is driven in the lineal path toward the printing position, for damping the printing impact of the hammer so that the printing impact decreases as the distance of hammer movement along the lineal path increases and for absorbing rebound energy by engagement with said front side of the slot upon hammer movement to a non-printing position following printing.

5. A combination accoding to claim 1 characterized by: means for moving said carrier longitudinally past said hammer to successively align carrier supported dies with said hammer for printing, said carrier having hammer distal and hammer proximate sides; a plurality of pallets, transverse to and slidably supported by the carrier and having a first end adjacent the hammer proximate side of the carrier and a second end adjacent the hammer distal side of the carrier, the dies being secured to the first end and the spacing between the dies and the hammer being adjustable by sliding the pallets transversely of the carrier; and a stop member, releasably secured parallel to the carrier along the hammer distal side thereof, for engaging the second end portions of the pallets to restrain the pallets from sliding transversely of the carrier and maintain the spacing of the dies and the hammer during printing.

6. A combination according to claim 1, including means for spacing said dies, when aligned for printing, varying distances from said hammer.

7. A combination according to claim 6 wherein said dies comprise a plurality of groups of different leNgths, and the spacing means includes means for spacing each group from said carrier a distance different from the spacing of any other group.

8. A combination according to claim 6 wherein each die, when aligned for printing, is spaced from said hammer a distance inversely proportional to the printing surface area of the character on each die to be printed.

9. In a printer of the type wherein printing is effected by driving an impacting means toward a selected one of a plurality of dies, each die having a printing surface area, a mechanism for increasing the impact force of the impacting means on the selected die as the printing surface area of the selected die increases comprising: a carrier spaced from the impacting means and arranged for a relative movement therewith; a plurality of die shanks mounted in and extending from the carrier for supporting the plurality of dies, the length of the die shanks being variable and set in accordance with the printing surface area of the die carried on each die shank; and means for decreasing the distance between the impacting means and the selected die as the printing surface area of the selected die increases so that the impact force on the selected die is increased as the printing surface area of the selected die increases.

10. In a printer of the type including means means for propelling a print hammer toward a selected one of a number of type dies to effect a printing operation, and means, engageable with a portion of the hammer as the hammer is propelled toward a type die, for damping the velocity of the print hammer prior to impact with the type die to absorb some of the hammer energy prior to printing, the improvement wherein: the propelling means is arranged for propelling the hammer toward the type die with the same velocity regardless of the type character to be printed; and the damping means is arranged for damping the hammer velocity varying amounts to reduce the printing energy varying amounts as a function of the size of the printing surface area on the die of the selected type character to be printed, so that the velocity is damped most and the least energy is exerted against dies having the least printing surface area.

11. A printer as recited in claim 10, wherein: the means for propelling includes means for initially positioning the hammer in the same position prior to propelling, regardless of the type character to be printed; and the means for damping includes a resilient bumper mounted in the printer for engaging a portion of the hammer prior to printing impact so as to absorb hammer energy and thus decelerate the hammer prior to printing, and means for setting the distance traveled by the hammer after striking the bumper and before impact with the type die in accordance with the type face area, so that the hammer travels the least distance before impact with a die of the largest area, and travels greater distances before impacting with dies of smaller area.

12. A printer as recited in claim 11, wherein th damping means includes means for setting the distance between the type dies and the bumper in accordance with type face area so that the dies with the smallest printing area are positioned furthest from the bumper in the printing position.

13. A printer as recited in claim 12, wherein the type dies are formed at the inner ends of type support members, and further comprising: a continuously traveling endless carrier mounted in the printer for advancement past the hammer, and carrying the type members so that the type dies face the hammer and continuously travel past the hammer in alignment therewith for printing; and a fixed back-up member mounted in the printer so that portions of the type support members travel along and engage the back-up member as they travel past the hammer, the type support members being formed of different lengths in accordance with type face area, so that the die faces are variably spaced from the bumper as they advance into The printing position aligned with the hammer.

14. A printer as recited in calim 13: wherein the type members comprise type pallets having elongated shanks with the type dies formed at inner ends thereof, the shanks comprising the type support members and being mounted in the endless carrier for advancement past the hammer so that the type dies face the hammer; wherein the back-up member comprises a fixed back-up bar mounted parallel to the bumper and engaging the outer ends of the shanks; and wherein the pallet shanks are made in different lengths in accordance with the type face area of the particular die carried by the pallet.

15. A printer as recited in claim 10, wherein the propelling means comprises: means for mounting the hammer for free linear reciprocating movement along a line of flight toward and away from a type die in printing position, so that an inner printing end of the hammer faces the type die and an outer end extends away from the type die along the line of flight; means for initially biasing the hammer to a fixed initial rest position spaced from the type die, in which the hammer occupies the same initial postion regardless of the character to be printed; and means for striking the inner end of the hammer when it is desired to print a character, with a force sufficient to propel the hammer toward the type die to print the character.

16. A printer as recited in claim 15, further comprising: an endless carrier for the type dies; means for mounting a font of type dies on the carrier for continuous movement past the line of flight and in intermittent momentary alignnment with the inner end of the hammer; and means for positioning the type dies on the carrier so that the faces of the dies are spaced variable distances from the hammer in the initial position, the spacing being set in accordance with the printing surface area of each die in the font so that those dies with the largest area are positioned closest to the hammer and those with the smallest area are spaced furthest from the hammer.

17. In combination with a teleprinter of the type having a chassis, a resilient bumper mounted in the chassis along an axis Y, and a print hammer reciprocable along a printing axis X to engage a type member to print a character and arranged so that a portion of the print hammer strikes the bumper to dampen the hammer energy prior to impact with the type member, an improved hammer assembly characterized by: the hammer having a slot extending therethrough parallel to the Y axis and centered on the printing aixs X, the hammer being mounted on the bumper so that portions of the bumper extend through the slot and are centered on the printing axis X, the slot being formed so that the portions of the bumper within the slot are enclosed on all sides by walls of the slot and the hammer slot reciprocates on the bumper along axis X as the hammer travels to and from the printing position, the slot being elongated with respect to the bumper along the X axis so that front and rear walls of the slot permit a predetermined length of reciprocation of the hammer with respect to the bumper.

18. A teleprinter assembly as recited in claim 17, further comprising: means for biasing the hammer to an initial nonprinting position where the front wall of the slot engages and is stopped by a front wall of the bumper, the bumper having resilient front and rear walls engageable alternately with the front and rear walls of the slot.

19. A teleprinter as recited in claim 17, wherein the hammer rebounds after printing and wherein the front wall of the slot strikes the front wall of the bumper on rebound to dampen the hammer rebound energy, the bumper having resiliant front and rear walls engageable alternately with the front and rear walls of the slot.

20. A teleprinter as recited in claim 17, further comprising: means for mounting the hammer in the chassis for linear reciprocating movement along the printing aXis X, axis X being a linear axis perpendicular to the bumper axis Y and passing through the center of the bumper.

21. A teleprinter assembly as recited in claim 20, wherein the hammer is symmetrical about the axis X in a plane through the X axis perpendicular to the Y axis.

22. A teleprinter assembly as recited in claim 21, further comprising: means for biasing the hammer to an initial nonprinting position where the front wall of the slot engages and is stopped by a front wall of the bumper, the bumper having resilient front and rear walls engageable alterantely with the front and rear walls of the slot; and wherein the front wall of the slot strikes the front wall of the bumper as the hammer rebounds after printing, to dampen the hammer rebound energy.

23. In a teleprinter assembly as recited in claim 17, of the type wherein the print hammer is propelled toward a slected one of a number of type dies to effect a printing operation, the improvement further characterized by: means for propelling the hammer toward the type die with the same initial velocity regardless of the type character to be printed; the bumper being positioned so that the rear wall of the slot engages the rear wall of the bumper prior to printing impact so as to absorb hammer energy and thus decelerate the hammer prior to printing; and means for setting the distance traveled by the hammer after striking the bumper and before impact with the type die in accordance with the type face area, so that the hammer travels the least distance before impact with a die of the largest area, and travels greater distances before impacting with dies of amaller area.

24. A teleprinter assembly as recited in claim 17, further comprising: means for mounting the hammer in the chassis for free linear reciprocating movement along the printing axis X toward and away from a type member in printing position aligned with the hammer along axis X, so that an inner printing end of the hammer faces the type die and an outer end extends away from the type die along the axis X; means for biasing the hammer to a fixed initial rest position spaced from the type member, in which the front wall of the slot engages and is stopped by the front wall of the bumper; and means for striking the inner end of the hammer when it is desired to print a character, with a force sufficient to propel the hammer toward the type die so that the rear wall of the slot engages the rear wall of the bumper to dampen the hammer velocity but so that the hammer continues moving into engagement with the type member to print a character.

25. A teleprinter assembly as recited in claim 24, wherein the means for striking comprises: a constantly rotating impeller wheel mounted parallel to the hammer along an axis parallel to the bumper axis Y, the impeller wheel having projections that rotate past the outer end of the hammer out of engagement therewith; and an interponent selectively insertable between an oncoming projection of the impeller wheel and the inner end of the hammer so that the projection strikes the interponent and forces it aganist the outer end of the hammer to propel the hammer linearly along the printing axis.

26. A teleprinter assembly as recited in claim 17, wherein the hammer comprises: an elongated body section extending linearly along and centered on the X axis, the slot being formed along a portion of the body section; an enlarged head section at the inner end of the body section and extending therefrom along the X axis toward a type member to be printed, the body section being relatively small in cross section compared to the head section; and an elongated tail section at the outer end of the body section and extending therefrom along the axis X away from the type member, the tail section being relatively small in cross section compared to the head section.

27. In combination with a teleprinter of the type having a print hammer linearly reciprocAble along a printing axis X to engage a type member to print a character and arranged so that a portion of the print hammer strikes a resilient bumper to dampen hammer energy prior to impact with the type member, an improved hammer assembly comprising: an elongated body section extending linearly along and centered on the X axis, the body section having a slot therethrough centered on and perpendicular to the X axis, in which the bumper is received so that the hammer can reciprocate with respect to the bumper, the slot having a rear wall which strikes the bumper to dampen the hammer energy; an enlarged head section at the inner end of the body section and extending therefrom along the axis X toward a type member to be printed, the body section being relatively small in cross section compared to the head section; and an elongated tail section at the outer end of the body section and extending therefrom along the axis X away from the type member, the tail section being relatively small in cross section compared to the head section.