US2480213A - Carriage control for typewriters and the like - Google Patents

Description

Aug. 30, 1949. F. BECKER CARRIAGE CONTROL FOR TYPEWRITERS AND THE LIKE Filed Dec. 30, 1946 IN VEN TOR.

FRED BECKER 2M 47%? ATTORNEY Patented Aug. 30, 1949 STAT ES Freed Becker, QueensaVill &&;.-N. Ya, assignon to? Underwaod.0orporation poration ofjDelaware Application December 30, 11746, SeriivDNm 719}158 5. Claims (Cl. 191-82);-

ihis invention relates to typewriting machines and the like, and more particularly topawlr-andratchet devices associated with the carriage lettor-feed mechanism and operative incident to returnof the carriage.

An object of theinvention is to provide, in. a carriage-control mechanism; an improved ratcheting device by which overloankingof the carriage upon returning it to start a new line of typing is obviated.

In typewriters of certain construction wherein the. margin-regulatin mechanism is at the front of the frame-like carriage and the letterteed mechanism. with: its carriage-carried rack is adjacent the rear of the carriage, there-is chance of overbanking occurring, particularly when-the carriage is returned manually with undue force or in power carriage-retunr machines; This overbanking is-due in partto the. inherent-yieldab le character of the carriage frame and to a backlash of the mechanisms involved in banisingthe carriage at the left hand, orline-start margin; In conventional mechanisms the.- actual overbanking results from the pawlvand'vratchet deviceassociatedwith the letter-feed mechanism ratcheting a letter-feed step beyond that determined by the margin regulator, so that after bankin the carriage at the leftmargin, when the letter-feed escapement resumes control: of the carriage, a discrepancy of one letter spacein the line-start position of the carriage iszhadh The present invention obviates this fault by providing a ratchet mechanismlin which thefpawl ma follow along with-the r-atchetwheel: or pinion an angular distance substantially greater than the pitch of the ratchet teeth, withoutratcheting intoa succeeding tooth. This enables the ratchet Wheel or pinion to-rotate,ifor instance, an angular distance equivalent to,. say, one and a third letter spaces, during the instant inwhich banking occurs; without the associated pawl ratcheting into a succeeding tooth. Thus the ratcheting device will maintain thesame interrelation between the carriage and letter-teed mechanism and will accommodate an appreciable over-travel of the carriage rack induced by the springing of the carriage frame and the taking up of backlash in the carriage-arresting parts.

Other objects of the invention are. inpart obvious and in part particularly pointed out asthe 2 proved; paw-l: andiratchet: device, themechanism amhdevicc beinggills the quiescent condition: with the-:carriage-at restlimpositionto start a new line ysllin zt Figureflziaaiviewvsimilar too-Figure 1:but howing the parts-oh the-feedmechanism; and ratchet device-inztiiepositions Whichthey may take at the instant: the; carriage ishanked; at; the line.- start on-lefthandim'argin, thairis; just after the return of: the; oamiage: iSi terminated; and

Figures 3: is: a diagrammatic; plan. view ofa th l: ynewriter carriage. showing: in. dot-and.- dashputline,somewhatexag erated, the yield; of the: carria e: incident; to; this banking.

Theinvention; is: advantageous.- paitticularly in its: operative relation: with the; IBJJLQFfGGd meek..- anism; oi thetypewriten; This mechanism may be; of} any, well-known kind and? operates, to advance: the: panensupporting: carriage; one letterspacecsteptincident to; the; typing of each characten-ofrthetyping line: When the typedline is completed the carriage isreturned; Figure: 3, either" manually orby power; to the line-start position as determined by the engagement of a coun-tcrstop; 5, onthe; carriage 6 with; an? adjust,- ably: positionable-margin. stcp- T: on the typewriter main frame.

Apart from: the improved ratchet device; of the invention,- the: letter-feed escapement mechanism illustrated is 0t conventional construction, a: briefi description Qt which follows.

A- toothed rock 8; is mounted on the carriage and meshes with an1escapement pinion 9 which aismserves ao a ratchet wheel; these members 8 and: a comprising an operative connection betweem thecarriage 6; and an escapement mechanism M). This mechanism includes mainly an escapement wheel: M with which a pivoted stepping dog: Lland a detent, dog 13; cooperate in the usual. mannerto control the letter-feed steps of thecarniiaga The carriage 6, is actuated; in the direction of the arrow in Figure l by the usual carriage springdrum, not shown; The feeddogs 1-21, 7 3 are-mounted on a dog rocker M rockable pivots l-5i The dog rocker is actuated by the type actions; oi the; typewriter through a universa1- ban nottshowni, to the dog rocker rear- Wendi-y. A spring l6: connected to the stepping dog t2 tends to pull; this dog rightward towarda stop 11- andis-biased so; as to. also restore the dog M to its forward, inactive position. The pinion or ratchet it andythe escapemen-t Wheel H aremblmted:to rotate-independently on a stud l8 secured to a. frame 210.- wh-ich. also mounts the pivots I5. The tension on the Car iage spring drum, tending to move the carriage rack 8 leftwardly and to rotate the pinion 9 counterclockwise, is transmitted from pinion 9 to the escapement wheel H by a novel ratchet pawl 22, hereinafter described. The teeth of the escapement wheel I I are beveled as shown and the detent dog l3 has its leading edge beveled on the'far side. As the dog rocker l4 rocks rearwardly the detent dog I3 engages the same tooth of wheel II that was engaged by the stepping dog l2, the bevels on dog l3 and the escapement wheel teeth facilitatin this engagement. As dog l2 leaves the wheel tooth, spring [6 swings this dog leftward against stop ll so that dog [2 is in a position to engage the next tooth of wheel II. This occurs incident to the type action restoring, the dog rocker l4, therefore, returning to its'forward position. As detent dog l3 leaves the wheel tooth and dog l2 assumes engagement with the next tooth, the tendency of the carriage to move leftward causes the escapement wheel H to rotate until dog [2, coming into engagement with a stop not shown, arrests wheel il in the position shown in Fig ure 1. Each letter-feed step of the carriage, including word spaces, is effected by a similar operation of the escapement mechanism.

Upon completion of a line of typing the carriage is returned to the line-start position as determined by the left-hand margin stops 5, 1. Before the carriage begins to return, the escapement mechanism and ratchet device are in the condition shown in Figure 1. As the carriage is moved in the return direction indicated by the arrow in Figure 2, the corresponding movement of the rack 8 rotates pinion 9 clockwise and this rotation, transmitted to the escapement wheel ll via the tensioned ratchetpawl 22, rotates the escapemen-t wheel ll slightly in a counter-feed direction until a back-check dog 23 mounted on the rocker M is engaged b the immediately preceding tooth of wheel II. This check dog 23 is urged leftwardly by a spring 24- to rest against a stop 25, the spring yielding to permit the check dog 23 to swing rightwardly and thus ratchet idly over each tooth of the escapement wheel during the letter-feed action. As the carriage continues its return travel the pawl 22 ratchets over each tooth of the pinion 9 until the return of the carriage is terminated at the line-start margin.

Pawl 22 is mounted on the escapement wheel I I in such manner as to be capable preferably of both pivotal and endwise or linear movement. A stud 27 secured to wheel I l projects from the face thereof into a slot 28 in the pawl, the slot extending substantially lengthwise of the pawl. A

spring 33 wound about a pin 3| on wheel H, has one end anchored in the wheel and has the other end pressing against the end of the pawl 22 opposite its slotted end, a groove in the pawl receiving the curved end of the spring. A cam pin 32 secured to wheel ll coacts with a cam 33 formed on pawl 22. The shape of the cam face 33 is such as to guide the pawl in a generally endwise or linear movement as generated by the action of the pawl tooth 22' as the pinion 9 turns clockwise and the pawl tooth follows along to a predetermined extent without ratcheting. The two positions taken by the pawl 22 at the start and at the conclusion of this follow-up action are shown in Figures 1 and 2, respectively. This motion of pawl 22, against the tension of spring 33, is taken while a straight or nearly straight intermediate portion of cam 33 rides along pin 32, and is terminated by an angular face or shoulder 34 of the cam coming against the pin. At the 4 other end, the cam face may take a slight turn from the straight portion, as indicated at 35, which acts to cam the pawl tooth 22' into the tooth space of pinion 9. Spring 30 is arranged so as to exert a pressure generally endwise of the pawl, tending to move the pawl, by coaction of cam 33, to the position of Figure l. The contour of the effective portion of cam 33 may be varied somewhat from that shown, it being noted that the function of this cam is to cause the pawl tooth 22' to seat positively into the tooth space of pinion 9 when no ratcheting takes place as during letter-feeding, and to cause the pawl tooth to move along with the same pinion tooth to a certain extent of, say, one and one-third times a tooth pitch or letter space without ratcheting.

The extent of follow-up movement of pawl 22 may be modif ed to suit various conditions in the typewriter. It is, however, desirable to limit this movement to a maximum of, say, one and a fraction letter-spaces as the back-spacing mechanism of the typewriter should operate to backspace the carriage to a corresponding extent. It may be here noted that the tooth pitch of pinion 9 is such that there is one tooth for each letter space or, in other words, if the letter spacing is ten per inch, there are ten tooth-spaces in pinion 9 for each inch of carriage travel.

The operating efiect of the pawl-and-ratchet device in obviating overbanking will now be described. It will be noted that at the start of carriage return .the escapement mechanism assumes the condition shown in Figure 2 but pawl 22 has not as yet moved relatively to wheel H and its tooth 22 is still engaged between the two teeth of pinion 9. It will be further noted that the escapement wheel II has rotated clockwise a slight degree from the Figure 1 position, as indicated by the rightward displacement of the dotted arrow on rack B from arrow 36 in Figure 2, and that pawl 22 has moved bodily with wheel I I. As the carriage continues to be returned pinion 9 now turns while wheel ll remains stationary, being held by check-dog 23. After pinion 9 has -turned a little more than, say, one and a third tooth spaces, during which rotation pawl 22 has moved along with the pinion, the endwise movement of pawl 22 is stopped by shoulder 34 and the pawl ratchets into the next tooth space. This ratcheting action occurs once for each letterspace distance of carriage return and until the carriage is stopped by the margin stops 5, 1. If the carriage were to be brought up lightly to the line-start position so that the margin stops 5, 1 just contacted lightly, the escapement mechanism l i would be as shown in Figure 2 but the pawl 22 would nevertheless be in its inactive position as in Figure 1. To clarify the description, the

position of slight advance of the escapement wheel H which it assumes during carriage return, may be disregarded except to note that the point of engagement of the margin stops 5, l is such as to allow for this slight advance, and that after carriage return the carriage settles back a corresponding extent as the escapement mechanism, particularly the feed dog [2, resumes |c0n- I 2, i3, 23 are in the Figure 2 position but the pawl tooth 22' is still in the position of engagement with pinion 9 as shown in Figure 1. This relation of pinion 9 and wheel H is indicated graphically by the two arrows 31 in Figure 1 being aligned with each other. As the forceful banking of the carriage occurs, with the tendency of overbanking as indicated by the dot-anddash outline of the carriage in Figure 3, the rack 8 moves rightwardly to an extent such as that indicated by the rightmost or solid arrow on rack 8 in Figure 2. This extent of course varies somewhat in accordance with the force of impact at the instant of banking the carriage, but for the purposes of this description it may be assumed to be about one and one-third letter spaces. The corresponding displacement of pinion 9 relatively to wheel 1! is shown by the displacement of the two arrows 36 in Figure 2. The tooth of pinion 9 with which pawl tooth 22' had been engaged before the tendency to overbank occurred is marked with a cross in Figures 1 and. 2. During this rotation of pinion 9, the pawl tooth 22' has moved out from the tooth space of pinion 9 and pawl 22 has advanced bodily with the pinion, so that notwithstanding the advance of pinion 9 to an extent greater than a tooth space, the pawl has not ratcheted into the next tooth space. Instead, at the end of the overbanking action, the pawl tooth 22 is still in such position that it will reengage in the same tooth space of pinion S that it engaged when the margin stops 5, I contacted lightly. In other words, the same letter space relation between the carriage 6 and the escapement mechanism I is maintained notwithstanding that the carriage rack 8 has overtraveled an appreciable degree beyond that at which the stops 5, I determine the line-start position. From this it will be seen that after the carriage has been fully banked and the rack 8 settles back to its normal relation with the margin stops, the pinion 9 will recede to a position in which the arrows 3! are again aligned and the pawl tooth 22 will again seat into the pinion tooth space with which it was previously engaged. During this recessive action, pawl 22. under the camming action assisted by spring 3|], retards from the Figure 2 position to the Figure 1 posit on as the arrows 3! move toward registry with each other. Meanwhile rack 8 has been restored to its position indicated by the dotted arrow. Following this the carriage settles to its normal letterfeed pos tion as escapement wheel I l resumes its Figure 1 position to again come under control of the feed dog I2 as the escapement mechanism resumes control of the carriage position.

Although in this applicat on, there is specifically described one embod ment which the invention may assume in practice, it will be understood that the invention may be modified and embod ed in various other forms without departing from its spirit or the scope of the appended claims.

What is claimed as new is:

1. In a typewriter or like machine, the combination with a carriage letter-feed escapement mechanism having dogs cooperating with a toothed escapement member to control the letterfeed steps, of a one-way drive device interposed between the carriage and the escapement mechanism and effective to enable return of the carriage without a ratcheting action of the escapement mechanism, said device including a toothed ratchet and a pawl and mounting means therefor having provision for limited movement of the pawl in a direction generally along the line of the ratchet tooth travel occurring incident to returning the carriage.

2. In a typewriter or like machine, the combination with a carriage letter-feed mechanism having dogs cooperative with a toothed escapement member to control the letter-feed steps, of a pawl-and-ratchet device interposed between the carriage and the letter-feed mechanism and effective to enable return of the carriage without a ratcheting action of the letter-feed mechanism, said device including a pawl and mounting means therefor providing for pivotal movement and lineal movement of the pawl, the latter to an extent greater than the pitch of the ratchet teeth.

3. In a carriage control for typewriters and the like having a letter-feed escapement, a line-start margin device and an operative connection between the carrlage and the escapement including a ratcheting device operative incident to returning the carriage to the line-start position, said ratcheting device comprising a pawl and mounting means therefor having provision for pivotal movement and linear endwise movement of the pawl to an extent greater than a step of letter feed.

4. In a carriage control for typewriters and the like having a letter-feed mechanism and a linestart margin device, the letter-feed mechanism including an escapement wheel and a back-check dog, an operative connection between the carriage and escapement wheel including a toothed ratchet coaxial with the escapement wheel, a springpressed pawl cooperating with said ratchet, and means mounting said pawl on the escapement wheel for limited movement relatively to said wheel and in the general direction of rotation of the ratchet teeth taken incident to returning the carriage to the line-start position determined by the margin device.

5. In a carriage control for typewriters and the like having a letter-feed mechanism and a linestart margin device, the letter-feed mechanism including an escapement wheel and a back-check dog, an operative connection between the carriage and escapement wheel including a toothed ratchet coaxial with said escapement wheel, a springpressed pawl cooperating with said ratchet, a pin-and-slot connection mounting said pawl on the escapement wheel, and a cam-and-follower device between said pawl and wheel, said connection and said cam device coacting to cause said pawl to follow along with the ratchet teeth to a limited extent during rotation of the ratchet incident to returning the carriage to the linestart position.

FRED BECKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 472,870 Ford Apr. 12, 1892 1,123,463 Anderson Jan. 5, 1915 2,385,035 Smathers Sept. 18, 1945

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