US3272305A - Ribbon lift mechanism - Google Patents

Description

Sept. 13, 1966 P. F. PAGE RIBBON LIFT MECHANISM 2 Sheets-Sheet 1 Original Filed Sept. 12, 1962 mw mw O R R @w .1! WM i 1. i @w m fiw mw on mm m K vw SQ Q3 it Qkm INVENTOR PAUL E PAGE Fem Wm ATTORNEYS Sept. 13, 1966 P. F. PAGE 3,272,305

RIBBON LIFT MECHANISM Original Filed Sept. 12, 1962 2 Sheets-Sheet 2 Fig -iA INVENTOR PA E PAGE I 2044/ ATTORNEYS United States Patent Ofiice 3,272,305 Patented Sept. 13, 1966 This is a division of application Serial No. 223,159, filed September 12, 1962.

This invention relates to ribbon lift mechanism for typewriter machines and more particularly to a ribbon lift mechanism for lifting a ribbon vertically from a rest position upwardly into the print line.

Mechanisms of the general type here under consideration have been in commercial use for some time and usually operate more or less satisfactorily but uneconomically since they require intricate levers which present many manufacturing problems. Such a mechanism which is difficult to manufacture, for example, is a parallelogram type of lift mechanism wherein a pair of lift arms are welded to a rod to make up the sides of a parallelogram frame for lifting a ribbon. Other machines use simple lift mechanisms consisting of levers and cams which however do not provide a substantially vertical ribbon motion but a vertically arcuate type of motion and which result in character smudges and perhaps even interference between the ribbon and the paper.

In accordance with one embodiment of the invention, the free end of a vibrator arm which is pivotally mounted for arcuate motion is linked to a follower pivotally secured to the ribbon support. The fol-lower is adapted to ride in an arcuate slot formed in a guide aflixed to the frame. Since the arcuate slot is not concentric with the arcuate motion of the arm, the path of motion of the ribbon support is linearly vertical.

It is accordingly among the objects of the present invention to provide a ribbon lift mechanism for actuating a ribbon in a substantially vertical plane.

Another object of the present invention is to provide a ribbon lift mechanism which is easily manufactured.

A further object of the invention is the provision for preventing interference between the ribbon and the paper by insuring the path of motion of the ribbon in a substantially vertical plane.

Still another object of this invention is to provide an improved ribbon lift mechanism.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which like reference numerals designate like parts throughout the figures thereof and wherein:

FIGURE 1 is an isometric view of the vibrator mechamsm;

FIGURE 1A is an elevation of a vibrator arm;

FIGURE 1B is a fragmentary elevation showing the relation between the vibrator and printing head.

As shown in FIGURE 1 a portion 20 of the typewriter frame supports a bracket 21 which carries a shaft 22 on which a ribbon vibrator assembly, generally indicated at 23, is rockably mounted. Vibrator 23 includes a pair of arms 24 and 25 provided respectively with ribbon supports 130 and 27 for a ribbon R which is adapted to be fed unidirectionally during successive typing operations in a manner described below. Arms 24 and 25 are substantially similar to the right of shaft 22 and are joined by a pin 26 which anchors one end of a return spring 26a, the other end of which is fastened to frame 20, spring 26a biasing the arms downwardly to their normal or rest position. Ribbon supports and 27 are respectively controlled in their vertical reciprocatory movement by frame supported guides 28 and 29 which have cam slots 28a and 29a adapted to receive cam follower pins 30 and 31 respectively. Pins 30 and 31 are secured to the ends of crank levers 32 and 33 respectively which are integrally formed with their respective ribbon supports 130 and 27 and are pivotally mounted to the ends of arms 24 and 25 by pins 24a and 25a. Thus, as the vibrator assembly 23 is rocked counterclockwise (as viewed in FIGURE 1), to elevate the ribbon supports, the ends of arms 24 and 25 follow an arcuate path which would cause the ribbon supports to follow an arcuate path were it not for the shape of the cam slots 28a and 29a.

That is to say, that the path of motion of the ribbon supports is adjusted and changed by the cam follower pins 30 and 31 which engage the cam slots 28a and 29a to pivot the ribbon supports around their respective pins 24a and 25a. Thus, by shaping the arcuate cam slots 28a and 29a to be non-concentric with the arcuate paths of movement of arms 24 and 25, the ribbon supports may be positioned in a vertical plane during the rocking of arms 24 and 25, thereby to present ribbon R in a vertical plane at the printing position. In other words, the arcuate movement of arms 24 and 25 is converted into linear vertical movement of supports 130 and 27. Conventional carbon ribbon usually measures about for reasons detailed below I prefer to use a carbon ribbon about /2" wide. Accordingly, the depth of the ribbon receiving slots 130a and 27a in supports 130 and 27 is slightly greater than /2", the supports being provided with ribbon retaining fingers 26b and 271) which help to maintain the ribbon flat in a vertical plane as it is reciprocated during ope-ration of the vibrator.

An actuating arm, generally indicated at 34, is pivotally mounted on a pin 35 carried by frame 20 and includes a crank 36 and a bifurcated drive arm 37, crank 36 and arm 37 being secured together in any suitable manner so as to oscillate as a unit about pin 35. As shown in FIGURE 1B, the lower end 36a of crank 36 is bifurcated to receive a pin 38 carried by a lever 39 fastened to a drive shaft 40 adapted to be oscillated by a suitably driven bell crank'70 whereby actuating arm 34 is rocked forth and back about pin 35.

The two :sides 37a and 37 h (FIGURE 1) of drive arm 37 have identical elongated slots 41 formed respectively therein through which extends a pin 42 that also extends through a slot 43 formed in a bichrome lever 44 whose lower end is pivotally connected to frame 20 in any suitable manner. It may be seen that pin 42 may ride forth and back in slots 41 and up and down in slot 43 for a purpose described below.

As shown in FIGURE 1A vibrator arm 25 includes a body 45 and a shoulder 46 the latter having a slot 47 formed therein having a bottom edge 48 and which is wider at its open end 47a than at its closed end 4712. This slot is adapted to receive pin 42 at any of the three positions, A, B, and C, to which it is selectively adjustable by manipulation of lever 44. As will become apparent hereinafter, position A is a fabric ribbon position operative to impart a full stroke to the vibrator arms so that typing will occur on the lower field of a fabric ribbon. Position B is a fabric ribbon position as well as a carbon ribbon position. With the apparatus conditioned for fabric ribbon and with lever 44 in the B position the vibrator arms can effect only a partial stroke so that typing will occur on the upper field of a fabric ribbon; with the apparatus conditioned for carbon ribbon and with lever 44 in the B position the vibrator arms will effect partial 'parts are in their normal position the bottom edges of slots 41 are in registry with bottom edge 48 (FIGURE 1A) of slot 47, pin 42 resting thereon in its B position. 'If now lever 39 is driven counterclockwise (FIGURE 1) actuating arm 34 will be rocked clockwise thus forcing pin 42 against slot edge 48 on vibrator arm 25 causing this arm as well as arm 24 to rock counterclockwise and partially elevate ribbon supports 27 and 130. Thus with 'the apparatus conditioned for fabric ribbon, the position of lever 44 determines the length of the moment arm (distance between pin 42 and shaft 22) thereby specifying either a full or partial stroke. On the other hand, with the apparatus conditioned for carbon ribbon, the lever 44 remains in the B position and the moment arm is changed in a manner to be described below.

According to the embodiment of the invention illustrated, the mechanism for alternately elevating the vibrator arms to a partial stroke and then to a full stroke is the same as the mechanism disclosed and claimed in my copending patent application 223,159 filed September 12, 1962. Therefore, insofar as is thought necessary, certain parts and functions of this mechanism will now be briefly described. Referring to FIGURE 1, I provide a cam and ratchet combination generally designated by numeral 50. The cam 51 takes the form of a Maltese Cross with symmetrical cam surfaces separated by radially extending valleys and may be integrally molded from a suitable plastic with a ratchet 54. The cam and ratchet combination 50 is mounted on a pin 59 such that when arms 24 and 25 are rocked up and down cam and ratchet 50 move with body 45; rotation of the cam and ratchet being effected as a result of return to rest movement of the arm as will be described below. A pawl 60 is pivotally mounted on a pin 61 secured to frame 20 and is biased counterclockwise by a spring 62 so that its tooth 60a tracks along the path defined by the teeth on ratchet wheel 54.

Another pawl 63 is pivotally mounted on a pin 64 secured to vibrator arm body 45 and is biased counterclockwise by a spring 65 so that it tracks over the same path as that of pawl tooth 60a. Cam and ratchet combination 50 together with pawl 60 coact with a drive pin 68 mounted on drive arm 37 to effect alternate full and half stroke drives of vibrator arms 24 and 25 in a manner now to be described.

Thus, during the first half cycle of operation (driving stroke) the ribbon supports 27 and 130 are driven a full or partial stroke depending on Whether a cam surface or a cam valley is positioned under drive pin 68 at the start of the cycle. During the second half of the cycle (return to rest stroke), cam 51 is indexed by pawl 60 and 'ratchet 54 to position the next cam surface or valley, as

the case may be, beneath pin 68 in preparation for the start of the next cycle. In other words, the moment arms are alternately 42-22 and 68-22 depending on the location of cam 51.

It is now apparent that the conditioning necessary for using fabric ribbon with the lever 44 in the B position a simply requires the disengaging of pawl 60 from ratchet 54 and insuring that a cam valley is under pin 68. As shown and described in my aforementioned copending application 223,159, a lever, such as the lever 145, may cooperate with a pawl lug 60b and engage one of the studs 160 to provide both of these functions.

As shown in FIGURE 1B, shaft 40 is mounted on a part of frame 20. As noted above bell crank 70 is secured to shaft 40 and has an arm a that is connected to the drive mechanism (not shown) of the machine. The other arm 70b of bell crank 70 is drivingly connected in any suitable manner to a shaft 72 reciprocally mounted in frame 20, the upper end of this shaft carrying a matrix or spring head 73. Vibrator arms 24 and 25 (FIGURE 1) straddle head 73 (FIGURE 1B) as also do ribbon sup ports and 27 which accordingly support the ribbon near the printing head at the printing position during a printing operation. Thus when crank 70 is driven head 73 and ribbon supports 130 and 27 are elevated so that a type character on head 73 and the ribbon are presented at the printing position where a hammer 74, driven by any suitable mechanism (not shown) effects an imprint in the well known manner.

It may now be seen that 'I have provided a ribbon handling mechanism that attains the several objects set forth above in a thoroughly practical and eflicient manner.

As other embodiments of the invention are possible and as changes may be made in the one disclosed without departing from the scope of the invention it is to be understood that the foregoing should be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a mechanism for moving a typewriter ribbon vertically with respect to a point of contact between a print element and a hammer or platen, the combination of,

a frame,

a pair of outwardly extending vibrator arms pivotally mounted on said frame the ends of said arms describing an arcuate path during pivotal movement thereof,

drive means for rocking said arms in synchronism with each typing stroke,

ribbon support means pivotally mounted on said arms for maintaining the ribbon in a vertical plane,

cam means secured to said frame,

and cam follower means secured to said ribbon support means and adapted to engage said cam means thereby to pivot said ribbon support means on said arms such that said ribbon support means are maintained in a vertical plane when said arms are rocked.

2. A mechanism in accordance with claim 1 wherein said cam means is comprised of a pair of cam plates each having an arcuate slot which is not concentric with said arcuate path and said cam follower means is comprised of a pair of depending arms each having a cam follower adapted to ride in a different one of said slots.

References Cited by the Examiner UNITED STATES PATENTS 493,255 3/1893 Densmore 197-167 581,500 4/1897 Webb 197-167 662,147 11/1900 Gabrielson 197-158 949,257 2/1910 Barney 197-158 1,064,703 6/1913 Brown 197-157 1,211,203 1/1917 McLaughlin 197-157 X 2,161,856 6/1939 Coxhead 197-151 2,692,556 10/1954 Anderson 197-157 X 2,747,718 5/1956 May 197-157 2,840,218 6/1958 Pelton 197-158 X 2,919,008 12/1959 Whippo 197-157 FCREIGN PATENTS 16,563 1913 Great Britain. 381,472 10/ 1932 Great Britain.

ROBERT E. PULFREY, Primary Examiner.

E. T. WRIGHT, Assistant Examiner.

Claims (1)

1. IN A MECHANISM FOR MOVING A TYPEWRITER RIBBON VERTICALLY WITH RESPECT TO A POINT OF CONTACT BETWEEN A PRINT ELEMENT WITH A HAMMER OR PLATEN, THE COMBINATION OF, A FRAME, A PAIR OF OUTWARDLY EXTENDING VIBRATOR ARMS PIVOTALLY MOUNTED ON SAID FRAME THE ENDS OF SAID ARMS DESCRIBING AN ARCUATE PATH DURING PIVOTAL MOVEMENT THEREOF, DRIVE MEANS FOR ROCKING SAID ARMS IN SYNCHRONISM WITH EACH TYPING STROKE, RIBBON SUPPORT MEANS PIVOTALLY MOUNTED ON SAID ARMS FOR MAINTAINING THE RIBBON IN A VERTICAL PLANE,

Images