US3458024A - Typebar drive including reciprocating linear moving cyclic means - Google Patents

Description

July 29, 1969 J. o. scHAEFE'R 3,453,024

TYPE -DRIVE INCLUDING RECIPROCATING NEAR MOVING CYCLIC MEANS Filed Sept. 18, 1967 2 Sheets-Sheet 1 INVENTOR. JOHN 0. SGHAEFER Mamm ATTORNEY United States Patent 3,458,024 TYPEBAR DRIVE INCLUDING RECIPROCATING LINEAR MOVING CYCLIC MEANS John O. Schaefer, Lexington, Ky., assignor to International Business Machines Corporation, Armonk, N.Y.,

a corporation of New York Filed Sept. 18, 1967, Ser. No. 668,416 Int. Cl. B41j 23/08, 23/38 US. Cl. 19717 21 Claims ABSTRACT OF THE DISCLOSURE A powered typewriter has each of its pivotally mounted typebars driven through a linearly moving bail to print the characters thereon. The typebar drive mechanism has means to regulate the force with which the selected character strikes the platen in accordance with the area of the character being printed. The mechanism includes means to store a second character during printing of the first character whereby typebar clashing is prevented. The typebar drive mechanism also includes means to prevent repeat actuation of a typebar until its keylever is released and returned to its rest position by the typist. The mechanism also has means to absorb part of the rebound energy of the typebar and its connecting linkage.

In powered typewriters having a typebar drive mechanism, the typebar has normally been driven from a power roll or a fluted drive shaft. While this type of drive mechanism is satisfactory, the present invention is an improvement thereover by eliminating the requirement for a power roll or a fluted drive shaft and utilizing a linearly moving bail. As a result, the number of parts required for the typebar drive mechanism is substantially reduced in comparison with the number of parts required by a typebar drive mechanism utilizing a power roll or a fluted shaft. Accordingly, the typebar drive mechanism of the present invention has a relatively lower cost.

While a typebar drive mechanism has previously been suggested in which an oscillating bail has been employed to drive the typebar in place of the power roll or the fluted drive shaft, this mechanism has utilized a plurality of parts between the character selection member and the connecting link of the typebar. Thus, this previously suggested typebar drive mechanism utilizing an oscillating bail has not substantially reduced the cost in comparison with a typebar drive mechanism utilizing a power roll or a fluted shaft.

The present invention satisfactorily solves the foregoing problem by employing a single actuating member between the character selection member and the connecting link of the typebar. Since this single actuating member may be easily stamped, a substantial reduction in cost is provided by the present invention in comparison with the previously suggested typebar drive mechanism utilizing an oscillating bail.

In the previously suggested typebar drive mechanism having an oscillating bail, the depression of a second keylever is prevented until completion of the print cycle of the prior selected character. While this prevents any clashing of the typebars since only one typebar can be selected, this substantially slows the operation of the machine. That is, the typist cannot select characters at a high rate of speed.

The present invention satisfactorily solves this problem by permitting the striking of two keys at a high rate of speed without permitting any clashing of the typebars. In the present invention, the striking of two keys at a high rate of speed results in the second character being stored until completion of the first print cycle. Since each print cycle of the mechanism of the present invention requires only sixty-five milliseconds, the typist is not aware of this character storage feature. Therefore, the speed of the typist is not retarded by the typebar drive mechanism of the present invention.

Since the various type characters have different areas, uneven type impressions will occur if the typebar were to move each character into engagement with the platen at the same velocity irrespective of the relative area of the character. While typebar drive mechanisms utilizing a power roll or a fluted drive shaft have previously employed type control impression means, the previously suggested typebar drive mechanism utilizing an oscillating bail does not suggest control of its printing impression.

The present invention satisfactorily solves this problem by utilizing a mechanism having a linearly moving bail in which the force with which the character strikes the platen is varied in accordance with the area of the character being printed. Thus, the maximum force occurs with the area of largest character while the minimum force occurs with the character having the smallest area.

In power operated typewriters, the rebound energy has presented a problem wherein the possibility of clashing or jamming of typebars has existed. In the prior typebar drive mechanisms, the typebar has usually depended upon engagement of the typebar with a rest bar to absorb the rebound energy. In certain instances, the typebar may oscillate upon initially striking the rest bar whereby the possibility exists that an adjacent typebar would engage this oscillating typebar during the next print cycle. Thus, the rebound energy has tended to limit the speed of operation of the machine.

The present invention satisfactorily solves the foregoing problem by utilizing an additional rebound energy absorber in which the typebar is immediately brought to rest so that there is no oscillation thereof. In the present invention, the separate rebound energy absorbing means cooperates with the actuating member to also lock the actuating member in its rest position.

An object of this invention is to provide a printing mechanism having a typebar drive mechanism of relatively low cost.

Another object of this invention is to provide a printing mechanism in which rapid selection of the type characters by the operator may occur with the characters being printed in the order of selection.

A further object of this invention is to provide a printing mechanism utilizing a linearly moving bail in which the print force varies in accordance with the area of the character being printed.

Still another object of this invention is to provide a powered typewriter in which clashing of the typebars is eliminated while still obtaining printing of the characters in the desired order.

The foregoing and other objects, features and adv-antages of this invention will be apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a schematic perspective view of a portion of the typebar drive mechanism of the present invention.

FIG. 2 is a side elevational view, partly in section, of a portion of the typebar drive mechanism of the present invention.

FIG. 3 is a timing chart showing the relationship of certain elements of the typebar drive mechanism during a print cycle.

FIG. 4 is an exploded perspective view of a portion of the linearly moving bail of the typebar drive mechanism of the present invention.

FIG. 5 is a perspective view of a portion of the typebar drive mechanism of the present invention.

Referring to the drawings and particularly FIGS. 1 and 2, there is shown a typewriter having a plurality of keylevers 11 (two shown in FIG. 1) with each of the keylevers 11 being pivotally mounted on a rod 12 having its ends supported in the frame of the typewriter 10. Each of the keylevers 11 has a keybutton 14 on one end thereof for actuation by a typist.

Each of the keylevers 11 cooperates with a separate actuating member or lever 15 to cause printing of a selected type character at a printing position when the keylever 11 is actuated by depressing the keybutton 14 to overcome a spring (not shown) urging the keylever 11 to its rest position. The keylever 11 has a dependent leg 16 with a projection 17 at the lower end of the leg. The projection 17 has its end surface engage end surface of a tab 18 on the actuating member 15 whereby the actuating member 15 is moved by the keylever 11.

Each of the actuating members 15 is mounted on a rod 19 having its ends supported by the frame of the typewriter 10. Each of the actuating members 15 has a slot 20 through which the rod 19 extends whereby the actuating member 15 may both pivot and slide forward and rearward.

The upper end of the actuating member 15 has one end of a link 21 pivotally connected thereto. The other end of the link 21 is pivotally connected to a typebar 22 having a pair of type characters 23 and 24 thereon in spaced relation to each other. The type character 23 is a lower case character while the type character 24 is an upper case character.

The typebar 22 is pivotally mounted on an arcuate fulcrum wire 25. When the typebar 22 is pivoted about the wire 25, one of the type characters 23 and 24 is printed through engagement of the selected character against a platen 26. It should be understood that paper (not shown) will be passed around the platen 26 and a ribbon (not shown) will be interposed between the type characters 23 and 24 and the paper to cause printing of the selected character on the paper.

The actuating member 15 has a first portion 27 extending rearwardly from the actuating member 15 for cooperation with a linearly moving bail 28, which includes a driving comb 29 and a guide comb 30. The combs 29 and 30 are fixedly secured together for linear movement together.

The driving comb 29 has a plurality of resiliently biased fingers 31 with each having a slot 32 therein of a shorter length than slots 33 in a plate, which forms the guide comb 30. Furthermore, the lower end of each of the slots 33 is disposed beneath the lower end of each of the slots 32.

Each of the slots 32 and 33 in the combs 29 and 30, respectively, cooperates with the first portion 27 of one of the actuating members 15. When the first portion 27 of one of the actuating members 15 is moved rearwardly due to actuation of the cooperating keylever 11, the lower surface of the first portion 27 will be positioned for engagement by the bottom surface of the slot 32. Thus, when the linearly moving bail 28 is moved upwardly, the actuating member 15 is moved to cause the selected type character 23 or 24 on the typebar 22 to be printed. It should be understood that the position of the bottom surface of the slot 33 with respect to the first portion 27 of the actuating member 15 is such that there is never any contact of the bottom surface of the slot 33 with the first portion 27.

The linear movements of the bail 28 are produced by rotation of a drive shaft 34. The drive shaft 34 has earns 35 (one shown) on each end thereof for cooperation with pivotally mounted cam followers 36 (one shown). Each of the cam followers 36 is pivotally connected to one of the ends of the bail 28 through being secured to an ear 37 (one shown) on the guide comb 30. The profile of each 4 of the cams 35 is such that rotation of the drive shaft 34 through results in a complete reciprocating movement of the bail 28 whereby the bail 28 is cyclic in operation. Thus, each cycle of the drive shaft 34 is 180 of rotation thereof.

Accordingly, whenever one of the actuating members 15 has its first portion 27 moved into a position in which the lower surface of the slot 32 in the drive comb 29 can engage the lower surface of the first portion 27, the actuating member 15 is ready for movement by the bail 28. When this occurs, the typebar 22 is pivoted to cause printing of one of the characters 23 and 24 thereon.

In order for the first portion 27 of one of the actuating members 15 to be disposed in a position for its lower surface to be engaged by the bottom surface of the cooperating slot 32 of the drive comb 29, a second portion 38, which extends rearwardly from the first portion 27, must have entered an aligned slot 39 in a ball interlock 40. The ball interlock comprises a tubular member 41, which is supported by the frame of the typewriter 10, with the slots 39 formed therein and each of the slots 39 aligned with one of the second portions 38 of the actuating member 15. Each end of the tubular member 41 is closed, and a plurality of balls 42 is disposed within the tubular member 41.

The total spaces between the balls 42 within the tubular member 41 are greater than the width of one of the second portions 38 but less than the width of two of the second portions 38 of the actuating members 15. Accordingly, the ball interlock 40 prevents pivoting of more than one of the typebars 22 at the same time for printing. This insures that there is no clashing between any of the typebars 22 due to the typist rapidly hitting two of the keybuttons 14.

Accordingly, when the actuating member 15 is moved rearwardly by depression of the keylever 11 due to the cooperation of the slot 20 with the rod 19, the second portion 38 of the actuating member 15 must enter the aligned slot 39 in the ball interlock 40 before the lower surface of the first portion 27 is disposed for engagement by the bottom surface'of the slot 32 of the drive comb 29. Therefore, unless none of the other actuating members 15 has its second portion 38 within the ball interlock 40, the actuating member 15 cannot be disposed for actuation by the linearly moving bail 28.

When the actuating member 15 is in its rest or inoperative position, a latching surface 43 on the actuating member 15 bears against the top surface of a resilient finger 44 adjacent its end. Each of the actuating members 15 cooperates with one of the resilient fingers 44 with the resilient fingers 44 extending from a support plate 45, which is supported by the frame of the typewriter 10. The resilient fingers 44 are biased in an upward direction.

When one of the keylevers 11 is moved downwardly by depressing the keybutton 14, the cooperating actuating member 15 attempts to slide rearwardly. If none of the other actuating members 15 is disposed within the ball interlock 40, then the actuating member 15 may have its second portion 38 move into the aligned slot 39 in the ball interlock 40. When the second portion 38 of the actuating member 15 has entered the ball interlock 40, the latching surface 43 is removed from engagement with the resilient finger 44 whereby the resilient finger 44 moves upwardly to contact a bail 46, which is crank mounted on the frame of the typewriter 10.

The upward movement of the bail 46 pivots a lever 47 counterclockwise to cause actuation of a clutch 48. When the lever 47 is pivoted counterclockwise, it ceases to hold one of two diametrically disposed lugs 49 of the clutch 48. When the clutch 48 is actuated, the drive shaft 34 is driven by a motor 50 through a toothed belt 51.

When the bail 46 is moved upward to actuate the clutch 48, the remainder of the print cycle cannot be interrupted so that the print cycle will be completed. Thus, the keyboard operation is completely serial. Furthermore,

the bail 46 functions as a defined trip point since the print cycle will be completed whenever the bail 46 is tripped.

The clutch 48 is of the helical spring type as more particularly shown and described in U.S. Patent 2,919,002 to Palmer. When the lever 47 ceases to hold the lug 49 of the clutch 48, a shaft 52 is connected to the drive shaft 34. The shaft 52 is connected to a pulley 53, which has the toothed belt 51 passing thereover to cause continuous rotation thereof.

Accordingly, actuation of the clutch 48 results in the drive shaft 34 being rotated through 180. (The engagement of the lever 47 with the other of the lugs 49 disconnects the clutch 48) whereby the bail 28 moves upwardly and then downwardly. During upward movement of the bail 28, the drive comb 29 causes pivoting of the actuating member whereby the typebar 22 is pivoted about the wire 25 to print the selected character.

The profiles of the cams are such that the typebar 22 is powered by the motor through the drive shaft 34 for only 62 of pivotal movement of the typebar 22 toward the platen 26. The remaining 30 of pivoting of the typebar 22 about the wire 25 until engagement with the platen 26 occurs is due to momentum created by the powered movement during the first 62 of pivoting of the typebar 22.

When the resilient finger 44 clears the latching surface 43 to actuate the bail 46, the end surface of the resilient finger 44 contacts a second latching surface 54 on the actuating member 15. This results in the resilient finger 44 latching the actuating member 15 in a position in which the second portion 38 of the actuating member 15'may be moved by the drive comb 29 of the linearly moving bail 28 to cause pivoting of the actuating member 15.

The end surface of the resilient finger 44 remains in contact with the latching surface 54 until pivoting of the typebar 22 through its first 36 (15 milliseconds) is com pleted. At this time, the tab 18 of the actuating member 15 engages the top surface of the resilient finger 44 to remove the end of the resilient finger 44 from engagement with the latching surface 54. As a result, the resilient finger 44 is disposed so as to no longer push upwardly on the bail 46.

The actuating member 15 and the typebar 22 are driven by the driveshaft 34 until the actuating member 15 and the typebar 22 have pivoted through 62. When the drive shaft 34 completes 62 of rotation of the cams 35, the profiles of the earns 35 are such that the cams 35 no longer accelerate the linearly movable bail 28 as they did during the first 62 of rotation of the drive shaft 34. Thus, the acceleration of the actuating member 15 and the typebar 22 in comparison with the acceleration of the bail 28 is such that the actuating member 15 will move away from the drive comb 29 during the remaining 30 of rotation of the drive shaft 34 during which the bail 28 continues to be moved upwardly. However, this deceleration of the bail 28 is necessary to change its direction of movement after 90 of rotation of the drive shaft 34 to insure that the bail 28 returns to its original position during the second 90 of rotation of the drive shaft 34.

Since the earns 35 decelerate the upward movement of the bail 28 after 62 of pivoting of the actuating member 15 and the typebar 22, the actuating member 15 and the typebar 22 are no longer driven. However, they continue to pivot, due to momentum, until the type character 23 or 24 engages the platen 26 to print the selected character.

When the actuating member 15 has pivoted 62, a depending finger on the actuating member 15 engages a rod 56, which is fixed to the frame of the typewriter 10. This results in the actuating member 15 ceasing to pivot about the rod 19 and starting to pivot about the fulcrum formed between the rod 56 and the depending finger 55 of the actuating member 15.

Thus, during the final 30 of pivoting of the typebar 22 toward the platen 26, the movement of the actuating member 15 is about the fulcrum between the depending finger 55 of the actuating member 15 and the rod 56. This results in the actuating member 15 not only pivoting but also sliding forward relative to the rod 19 due to the slot 20.

The force with which the type character 23 or 24 strikes the platen 26 is regulated in accordance with the area of the character being typed. Thus, characters of large area (W, for example) require a greater force to strike the platen 26 than characters of small area (i, for example). By varying the force with which the character strikes the platen 26 in accordance with the area of the character, a substantially uniform printing impression is produced.

The force with which the selected character engages the platen 26 is controlled in the present invention by varying the resisting force of each of the resilient fingers 44 against which the tab 18 of the actuating member 15 engages during pivoting of the typebar 22 to its printing position whereby the velocity of the typebar 22 is regulated. The control of the velocity of the typebar 22 by the resilient finger 44 occurs only after powered drive of the actuating member 15 and the typebar 22 by the drive shaft 34 has ceased.

It should be understood that the resilient finger 44 always exerts an upward force when engaged with the actuating member 15 due to the resiliency of the finger 44. However, the restraining or resisting force of the resilient finger 44 is that force created due to changing the fulcrum point of the resilient finger 44.

If a character with the largest area is to be printed, then no restraining force against downward movement of the resilient finger 44 by the tab 18 of the actuating member 15 except for the inherent resilient force of the resilient finger 44 would occur until the platen 26 is engaged by the selected character on the typebar 22. However, if a minimum force is required due to the selected character having the smallest area, then the resilient finger 44 tends to resist the movement of the tab 18 from the time that powered movement of the actuating member 15 ceases.

An impression control means determines the resistance by each of the resilient fingers 44. The impression control means includes a curved bar 57, which is pivotally mounted on the frame of the typewriter 10 about the center of curvature of the curved bar 57. The curved bar 57 has a first set of screws 58 and a second set of screws 59 threadedly mounted therein. One of the screws 58 of the first set and one of the screws 59 of the second set cooperate with each of the resilient fingers 44. The screws 58 cooperate with the fingers 44 when one of the lower case characters 23 is to be printed. The screws 59 of the second set cooperate with the resilient fingers 44 when the selected character is one of the upper case characters 24.

The distance that each of the screws extends from the surface of the curved bar 57 determines the force with which the typebar 22 moves the selected character into engagement with the platen 26. Thus, if the screw does not extend beyond the surface of the curved bar 57, then the resilient finger 44 does not exert any force against movement of the actuating member 15 until the character strikes the platen 26 whereby the typebar 22 has its greatest velocity and strikes the platen 26 with the greatest force.

When the screw extends a maximum distance from the surface of the curved bar 57, the resilient finger 44 resists the pivotal movement of the actuating member 15 from the time that powered movement of the actuating member 15 and the typebar 22 ceases. Thus, the angular velocity of the actuating member 15 and the typebar 22 is reduced to a minimum so that the force with which the selected character strikes the platen 26 is a minimum.

This would occur when a character of the smallest area was being printed.

In the position shown in FIG. 1, the curved bar 57 is positioned with the first set of the screws 58 adapted to cooperate with the resilient fingers 44. This is with the fulcrum wire 25 positioned so that the lower case characters 23 will be printed.

The second set of the screws 59 cooperates with the resilient fingers 44 when one of the upper case characters 24 is to be printed. This position is obtained by depressing a shift key (not shown) to cause downward movement of the fulcrum wire 25 and counterclockwise pivoting of the curved bar 57. The shift mechanism is preferably of the type shown and described in pages 90 to 98 of IBM Customer Engineering Instruction Manual For Standard Typewriter, Model C-l, Copyrighted 1960.

When shifting occurs, the curved bar 57 is pivoted by a link 60, which is connected through suitable linkage (not shown) to the shift mechanism. This linkage would be connected to th segment support of the shift actuating mechanism shown in FIGURE 93 on page 91 of the aforesaid IBM Customer Engineering Instruction Manual.

In addition to the impression control means in which the force with which the typebar 22 causes the selected character to strike the platen 26 is regulated in accordance with the area of the character being typed, there also is provided a manual impression control means for use by the typist. This manual control means permits the typist to vary proportionally the force with which each of the characters strikes the platen 26.

This manual impression control means is not utilized to change the force with which the character strikes the platen 26 in accordance with its area. Instead, this manual impression control means is employed to determine whether printing will be light or heavy. For example, a greater force from each of the characters would be desired when many carbons are being typed so that heavy printing would be desired.

This manual impression control means includes a rod 61 (see FIG. 2) having its opposite ends supported in slots in the frame of the typewriter 10. The rod 61 is supported on a plate 62 during its movements by the typist. One end of the rod 61 would be connected through suitable linkage to an exterior control knob for movement by the typist.

In the position shown in FIG. 2, the rod 61 is positioned to permit the greatest force to be exerted when a character strikes the platen 26. As the rod 61 is moved away from a stop 63 on the plate 62, it changes the fulcrum position of all of the resilient fingers 44. As a result, the force with which the character strikes the platen 26 is reduced due to the resilient finger 44 resisting movement by the tab 18 of the actuating member earlier during the pivoting of the actuating member 15 after its powered rotation is stopped. The position of the rod 61 determines the resisting force of the resilient finger 44 to the movement of the actuating member 15. Thus, as the rod 61 moves away from the stop 63, the resilient finger 44 exerts a greater resisting force to the movement of the acutating member 15 after its powered drive ceases.

When the typebar 22 completes printing of the selected character, it rebounds away from the platen 26 with a substantial force due to the engagement of the type character with the platen 26. This rebound energy of the typebar 22, the link 21, and the actuating member 15 must be absorbed. All of this rebound energy has previously been absorbed by a rest bar 64. The rest bar 64 is curved in the same manner as the wire so as to cooperate with each of the typebars 22.

In the present invention, a portion of this rebound energy is absorbed by a resilient finger 65, which is supported on a casting 66 fixed to the frame of the typewriter 10. The resilient finger 65 has its lower end 67 hearing against a latching surface 68 of the actuating member 15. Thus, as the actuating member 15 returns to its rest position, the latching surface 68 engages against the lower end 67 of the finger to cause absorption of the rebound energy whereby there is no oscillation of the actuating member 15 due to the rebound energy. The lower end 67 of the finger 65 also latches the actuating member 15 against movement when it is not selected by movement of the cooperating keylever 11.

A stop 69 is supported by the casting 66 on the rear side of the finger 65 and prevents the rebound energy from moving the latching surface 68 of the actuating member 15 past the lower end 67 of the finger 65. Thus, the stop 69 insures that there is no oscillation of the actuating member 15 due to the rebound energy.

The casting 66 also supports a plurality of resilient fingers 70 forwardly of the fingers 65. Each of the fingers 70 cooperates with one of the actuating members 15 by bearing against a curved portion 71 of the actuating member 15 to continuously urge the member 15 to its rest position.

The casting 66 also has a guide 72 attached thereto for cooperation with the guide comb 30 of the linearly moving bail 28. The linearly moving bail 28 is continuously urged counterclockwise by springs 73 (one shown) connecting each of the cam followerrs 36 to the guide comb 30 of the bail 28.

It should be understood that the casting 66 has slots formed therein for cooperation with each of the actuating members 15. This permits movement of the actuating member 15 without any contact with the casting 66.

When the actuating member 15 returns to its rest position, the end surface of the tab 18 is spaced from the end surface of the projection 17 of the depending leg 16 of the keylever 11 (as shown in FIG. 1) if the typist has released the keylever 11. However, if the typist should not release the keylever 11 but maintain it depressed, the projection 17 of the keylever 11 will be disposed above the tab 18 when the actuating member 15 returns to its rest position. Accordingly, the tab '18 of the actuating member 15 will engage a cam surface 74 beneath the projection 17 to cam the depending leg 16 of the keylever 11 to the side and out of the path of the tab 18 of the actuating member 15 to permit the actuating member 15 to return to its rest position. As a result, the depression of the keylever 11 by the typist cannot cause another cycle for the cooperating actuating member 15 until the keylever 11 is released and again depressed.

When the keylever 11 is released, it returns from a position in which it is disposed at the side of the tab 18 to the position of FIG. 1 wherein the end surface of the projection 17 is disposed in spaced relation to the end surface of the tab 18. In this position, depression of the keylever 11 results in the actuating member 15 again being shifted rearwardly to move through another of its print cycles.

Considering the operation of the typewriter of the present invention, it will be assumed that all of the keylevers 11 are in their rest or non-depressed positions. When one of the keylevers 11 is depressed, the actuating member 15 is pushed rearwardly to move the second portion 38 into the aligned slot 39 in the ball interlock 40. When this occurs, the lower surface of the first portion 27 of the actuating member 15 is disposed for engagement by the bottom surface of the slot 32 in the drive comb 29. When sufiicient rearward sliding of the actuating member 15 due to the slot 20 cooperating with the rod 19 has occurred because of the depression of the keylever 11, the top surface of the resilient finger 44 no longer engages the latching surface 43 of the actuating member 15. As a result, the resilient finger 44 moves upwardly to raise the bail 46. As soon as the resilient finger 44 clears the latching surface 43, it engages the latching surface 54 during its upward movement of the bail 46 whereby the upward movement of the bail 46 is limited.

The upward movement of the bail 46 causes counterclockwise pivoting of the lever 47 to allow the clutch 48 to connect the shaft 52 to the drive shaft 34 whereby the motor 50 rotates the drive shaft 34. When the bail 46 is tripped by being moved upwardly by the resilient finger 44, the actuating member ceases to slide rearwardly since it is at its rearmost position due to the length of the slot 20. In this position, the lower surface of the first portion 27 of the actuating member 15 is disposed for engagement by the bottom surface of the slot 32 in the drive comb 29. This insures that the actuating member 15 is pivoted when the linearly moving bail 28 is moved upwardly.

As shown in the timing cycle of FIG. 3, the actuating member 15 does not slide but only pivots when the actuating member 15 is being driven by the motor 50. As shown at point 75 in the timing cycle of FIG. 3 for indicating the pivotal movement of the actuating member 15, the second portion 38 of the actuating member 15 is removed from the aligned slot 39 in the ball interlock 40 after about 30 (twelve milliseconds) of rotation of the actuating member 15.

When the second portion 38 of the actuating member 15 is removed from the aligned slot 39 of the ball interlock 40, another of the actuating members 15 may have its second portion 38 enter its aligned slot 39 in the ball interlock 40. Thus, a selected character may be stored during the additional part of the cycle by the mechanism of the present invention due to the removal of the first of the actuating members 15 from the ball interlock 40. This permits the typist to rapidly hit two of the keybuttons 14 and have both selected characters printed in the desired sequence. However, because of the ball interlock 40, there is no possibility of two of the typebars 22 clashing since only one of the typebars 22 can be actuated for printing.

The driving of the actuating member 15 continues until 62 of pivotal movement thereof is completed. At this time, the drive comb 29 ceases to engage the first portion 27 of the actuating member 15 to end driving of the actuating member 15 by the linearly moving bail 28. At the same time, the depending finger 55 of the actuating member 15 engages the fulcrum rod 56. Thus, forward motion of the actuating member 15 occurs as shown in the timing cycle of FIG. 3 for indicating sliding motion of the actuating member 15.

The forward motion of the actuating member 15 ceases before the completion of the cycle. Therefore, the first portion 27 of the actuating member 15 is removed from the slot 32 in the drive comb 29 before the drive comb 29 returns to its rest position.

When the depending finger 55 engages the rod 56, pivoting of the actuating member 15 occurs about the rod 56 until printing of the selected character occurs. Thereafter, pivoting of the actuating member 15 is about the rod 19 until the print cycle is completed.

As previously mentioned, the force with which the selected character engages the platen 26 is determined by the velocity of the typebar 22. The velocity of the typebar 22 is regulated by the position of the screw 58 of the first set of the screws or the screw 59 of the second set depending on whether the character 23 or the character 24 is being printed. This position of the screw determines when the resilient finger 44 bears against the tab 18 to restrict the pivotal motion of the actuating member 15. It should be understood that the resilient finger 44 is in engagement with the tab 18 during its driven movement but the finger 44 cannot be engaged with one of the screws in the curved bar 57 until free flight movement starts.

When the character has been printed, the momentum from the engagement of the character with the platen 26 results in the typebar 22 returning until it abuts against the rest bar 64. At the same time, the latching surface 68 of the actuating member '15 contacts the lower end 67 of the resilient finger 65 whereby the rebound energy is obsorbed. This also prevents any oscillation of the actuating member 15.

If a second of the keylevers 11 has been actuated by the typist before completion of a print cycle of a first of the actuating members 15, the second actuating member 15 will be stored in the ball interlock 40 until the completion of the cycle of the first actuating member 15. The rearward motion of the second actuating member 15 into the ball interlock 40 results in the cooperating resilient finger 44 ceasing to engage the latching surface 43 of the second actuating member 15 whereby the finger 44 maintains the bail 46 in an upper position to hold the pivoted lever 47 in a position so that it does not engage the next of the lugs 49 of the clutch 48. As a result, the clutch 48 remains engaged to cause another cycle of the drive shaft 34 to occur.

When the second of the keylevers 11 is actuated before completion of the prior print cycle, the drive comb 29 is not in its lowermost position so that the first portion 27 of the second of the actuating members 15 will not enter the slot 32 in the resilient finger 31 but merely pushes the resilient finger 31 rearwardly. However, as soon as the drive comb 29 returns to its lowermost position at the end of the print cycle, the finger 31 moves forwardly to cause the slot 32 to receive the first portion 27 whereby the lower surface of the first portion 27 is engaged by the bottom surface of the slot 32 to start another print cycle.

The solid line position of the bail in the timing cycle of FIG. 3 is when another of the keylevers 11 is not actuated. If a second of the keylevers 11 is actuated, then the ball 46 will again raise upwardly at 30 and remains in the upward position until another cycle starts as indicated by the dotted line. When this occurs, the bail 46 would move downwardly at the start of the next cycle in the same manner as shown in FIG. 3.

It should be noted that the resilient finger 44 reaches its lowermost position at the completion of the free flight of the actuating member 15. Thereafter, as the actuating member 15 pivots back to its rest position, the resilient finger 44 returns to its rest position by following the movement of the actuating member 15.

An advantage of this invention is its relatively low cost. Since the actuating member 15 performs the functions of several diflerent levers of presently available typebar drive mechanisms, this substantially reduces the cost. Furthermore, all of the parts of the typebar drive mechanism of the present invention may be formed by stamping so that this also substantially decreases manufacturing costs.

Another advantage of this invention is that it reduces the number of parts required for a typebar drive mechanism by eliminating the need for a power roll or fluted drive shaft. Still another advantage of this invention is that it eliminates typebar clashing. A further advantage of this invention is that it permits the storage of one type character while another is being printed.

While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. A mechanism for printing a selected type character at a printing position comprising:

a plurality of character selection members;

a plurality of actuating means equal in number to said character selection members;

each of said character selection members cooperating with one of said actuating means to move said actuating means; each of said actuating means having at least one type character connected thereto for printing at the printing position when said actuating means is actuated;

cyclic means cooperating with each of said actuating means;

said cyclic means including reciprocating means for engaging each of said actuating means when said actuating means is disposed in an actuating position;

said reciprocating means of said cyclic means actuating one of said actuating means to print the selected character at the printing position after said one actuating means is moved by said cooperating character selection member into the actuating position;

said reciprocating means of said cyclic means having yieldable means cooperating with each of said actuating means to prevent actuation of another of said actuating means during movement of said one actuating means by said reciprocating means of said cyclic means, said yieldable means allowing actuation of said another actuating means by said reciprocating means of said cyclic means after movement of said one actuating means is completed; and

means to store the selection of another character connected to said another actuating means and selected during actuation of said one actuating means by said reciprocating means of said cyclic means;

said storage means positioning said another actuating means for automatic engagement by said reciprocating means of said cyclic means in the next cycle of said cyclic means.

2. The mechanism according to claim 1 including:

means to drive said cyclic means;

and means to activate said drive means after said cooperating character selection member moves said one actuating means into position for cooperation with said cyclic means.

3. A mechanism for printing a selected type character at a printing position comprising:

a plurality of character selection members;

a plurality of actuating means with each of said actuating means cooperating with one of said character selection members;

each of said actuating means having at least one type character connected thereto for printing when said actuating means is actuated;

means cooperating with each of said actuating means,

said cooperating means actuating one of said actuating means to print the selected character at the printing position after said one actuating means is moved by said cooperating character selection member into a position for cooperation with said cooperating means; and

means cooperating with each of said actuatin means to regulate the force with which each of said actuating means moves the character connected thereto into engagement with a platen to print the character in accordance with the area of the character;

said force regulating means including:

a plurality of resilient fingers, each of said resilient fingers engaging one of said actuating means; and

means to vary the force exerted by each of said resilient fingers against said actuating means in accordance with the area of the character.

4. The mechanism according to claim 3 including:

means to activate said cooperating means in response to movement of said character selection member; and

said activating means including said cooperating resilient finger of said force regulating means.

5. The mechanism according to claim 3 in which said 6. The mechanism according to claim 4 in which said resilient finger latches said actuating means in position for engagement with said cooperating means.

7. The mechanism according to claim 3 in which said cooperating means is cyclic.

8. The mechanism according to claim 3 in which said cooperating means engages said actuating means when said cooperating means actuates said actuating means, said cooperating means ceasing to engage said actuating means before the selected character engages the platen; and

said force regulating means being effective only after said cooperating means ceases to engage said actuating means.

9. A mechanism for printing a selected type character at a printing position comprising: a plurality of character selection members;

a plurality of actuating means with each of said actuating means cooperating with one of said character selection members;

each of said actuating means having at least one type character connected thereto for printing when said actuating means is actuated;

reciprocating linear moving cyclic means cooperating with each of said actuating means, said cyclic means actuating one of said actuating means to print the selected character at the printing position when said one actuating means is moved by said cooperating character selection member into a position for cooperation with said cyclic means, said cyclic means imparting a substantially constant energy to each said actuating means independent of the area of the character connected thereto; and

means engaging said actuating means when said actuating means is in motion to regulate the force with which each of said actuating means moves the character connected thereto into engagement with a platen to print the character in accordance with the area of the character, said engaging means regulating the force by removing a portion of the substantially constant energy imparted to said actuating means by said cyclic means.

10. The mechanism according to claim 9 including means to store the selection of another character connected to another of said actuating means after said one actuating means is actuated by said cyclic means, said 40 force regulating means also functioning as said storage means.

11. The mechanism according to claim 6 in which:

said actuating means includes an actuating member;

a plurality of typebars with each of said typebars having at least one type character thereon for printing when said typebar is actuated;

means to connect each of said actuating members to one of said typebars; and resilient means engaging each of said actuating members to absorb rebound energy of said typebar, said connecting means, and said actuating member after the selected character has been printed.

12. A mechanism for printing a selected type character at a printing position comprising:

a plurality of character selection members;

a plurality of actuating means with each of said actuatmg means cooperating with one of said character selection members;

each of said actuating means having at least one type character connected thereto for printing when said actuating means is actuated;

cyclic means cooperating with each of said actuating actuating means to print the selected character means is moved by said cooperating character selec- 6 tion member into a position for cooperation with said cyclic means;

and means to regulate the force with which each of said actuating means moves the character connected thereto into engagement with a platen to print the character in accordance with the area of the character;

silient fingers engaging one of said actuating means; and

means to vary the force exterted by each of said resilient fingers against said actuating means in accordance with the area of the character. 13. The mechanism according to claim 6 in which each of said actuating means has two characters connected thereto; and sadi force varying means has:

means to vary the force of each of said resilient fingers against said actuating means in accordance with the area of one of said characters when said one character is to be printed; and means to vary the force of each of said resilient fingers against said actuating means in accordance with the area of the other of said characters when said other character is to be printed. 14. The mechanism according to claim 9 including: means to activate said cyclic means in response to movement of said character selection member; and said activating means including said cooperating resilient finger of said force regulating means. 15. A mechanism for printing a selected type character at a printing position comprising:

a plurality of character selection members;

a plurality of actuating members with each of said actuating membtrs cooperating with one of said character selection members;

a plurality of typebars with each of said typebars having at least one type character thereon for printing when said typebar is actuated;

each of said actuating members being mounted for pivotal and sliding movement and connected to one of said typebars;

reciprocating means to cooperate with each of said actuating members;

said actuating member being movable only in a first direction by said cooptrating character selection member is actuated whereby said actuating member is positioned for engagement by said reciprocating means;

means to retain said actuating member in position for engagement by said reciprocating means, said retaining means urging said actuating member into the position in which it is engaged by said reciprocating means until said reciprocating means ceases to drive said actuating member at which times said retaining means becomes ineffective; and

said reciprocating means moving in a direction substantially normal to the first direction when said reciprocating means is actuated, said retaining means and said reciprocating means cooperating when said reciprocating means is actuated so that said reciprocating means only pivots said actuating member as long as said reciprocating means engages said actuating member to cause printing of the selected character at the printing position.

1-6. A mechanism for printing a selected type character at a printing position comprising:

a plurality of character selection members;

a plurality of actuating members with each of said actuating members cooperating with one of said character selection members;

a rod having a longitudinal axis;

each of said actuating members having a slot therein for mounting said actuating members on said rod for both pivoting and sliding;

a plurality of typebars with each of said typebars having at least one type character thereon for printing when said typebar is actuated;

means to connect each of said actuating members to one of said typebars;

pivot means separate from said rod;

means to move each of said actuating members to cause printing of a selected character, said actuating member being slidable relative to said rod in a direction substantially perpendicular to the longitudinal axis of said rod when said cooperating character selection member is actuated to move said actuating member into position for movement by said moving means whereby there is no movement of said connecting means and said typebar; and

said moving means causing both pivoting and sliding of one of said actuating members after one of said character selection members is actuated to move said one actuating member into position for movement by said moving means;

said pivoting of said actuating member initially occurring about the longitudinal axis of said rod without sliding of said actuating member relative to said rod in a direction substantially perpendicular to the longitudinal axis of said rod, said pivoting occurring about said pivot means when said actuating member slides relative to said rod in a direction substantially perpendicular to the longitudinal axis of said rod.

17. The mechanism according to claim 16 including means on said actuating member to allow activation of said moving means after said actuating member has completed sliding movement by said cooperating character selection member.

18. The mechanism according to claim 16 in which said moving means is cyclic.

19. A mechanism for printing a selected type character at a printing position comprising:

a plurality of character selection members;

a plurality of actuating members with each of said actuating members cooperating with one of said character selection members;

a rod;

each of said actuating members having a slot therein for mounting said actuating members on said rod for both pivoting and sliding;

a plurality of typebars with each of said typebars having at least one type character thereon for printing when said typebar is actuated;

means to connect each of said actuating members to one of said typebars;

means to move each of said actuating members to cause printing of a selected character, said actuating member being only slidable when said cooperating character selection member is actuated to move said actuating member into position for movement by said moving means whereby there is no movement of said connecting means and said typebar;

said moving means causing both pivoting and sliding of one of said actuating members after one of said character selection members is actuated to move said one actuating member into position for movement by said moving means;

means to activate said moving means;

a separate resilient finger engaging each of said actuating members and adapted to actuate said activating means; and

means on said actuating member to release said resilient finger after said actuating member has completed sliding movement by said cooperating character selection member, said resilient finger actuating said activating means upon release by said releasing means.

20. The mechanism according to claim 19 including:

means on said actuating member engaging said resilient finger after said resilient finger is released by said releasing means; and

means to vary the resisting force urged by said resilient finger against said engaging means on said actuating member to regulate the force with which each of said typebars moves the character thereon into engagement with a platen to print the character thereon in accordance with the area of the character.

21. mechanism for printing a selected type character at a prlnting position comprising: i

a plurality of character selection members;

a plurality of actuating means equal in number to said character selection members;

15 each of said character selection members cooperating with one of said actuating means to move said actuating means; each of said actuating means having at least one type character connected thereto for printing at the printing position when said actuating means is actuated; cyclic means cooperating with each of said actuating means, said cyclic means actuating one of said actuating means to print the selected character at the printing position when said one actuating means is moved by said cooperating character selection member into a position for cooperation with said cyclic means; said cyclic means includes:

a reciprocating member having a plurality of resiliently biased fingers; each of said resiliently biased fingers having a slot therein adapted to receive one of said actuating means whereby movement of said actuating means into said slot results in actuation of said actuating means when said reciprocating member is reciprocated; means cooperating with said actuating means to prevent actuation by said cyclic means of another of said actuating means during movement of said one actuating means by said cyclic means; and said cooperating means includes a non-slotted portion of said resiliently biased finger engaging said another actuating means during movement of said reciprocating member to prevent said another actuating means from being moved into said slot in said resiliently biased finger until completion of a cycle of said reciprocating member during which said one actuating means is actuated.

References Cited UNITED STATES PATENTS 1,156,288 10/1915 Hausberg 197-14 1,178,879 4/1916 Schnyder 197-14 1,455,112 5/1923 Crawley 197-17 1,927,761 9/1933 TauSChek 197-14 1,955,987 4/1934 Trego 197-14 2,129,866 9/1938 Page 197-14 2,521,478 9/1950 Petit 197-17 2,891,649 6/1959 Peterson 197-14 3,151,722 10/1964 Salto 197-17 3,191,740 6/1965 Smusz et al 197-107 XR 3,327,828 6/1967 Dannatt 197-16 XR EDGAR S. BURR, Primary Examiner U.S. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,458 ,024 July 29 1969 John O. Schaefer It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, line 14, "48)" should read 48.) line 45, "driveshaft" should read drive shaft Column 9, line 74, "obsorbed" should read absorbed Column 12, line 42, claim reference numeral "6" should read 9 line 62, cancel "actuating"; same line 62, after "character" insert at the printing position when said one actuating Column 13, line 3, claim reference numeral "6" should read 12 line 15, claim reference numeral "9" should read l2 line 24, "membtrs" should read members line 35, "cooptrating" should read cooperating line 36, after "member", first occurrence, insert when said cooperating character selection member Signed and sealed this 28th day of April 1970.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR. Attesting Officer Commissioner of Patents

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