US3438477A

US3438477A - Platen reversing means for a printing apparatus

Info

Publication number: US3438477A
Application number: US562778A
Authority: US
Inventors: Vernon H Foersterling
Original assignee: VERNON H FOERSTERLING
Current assignee: VERNON H FOERSTERLING
Priority date: 1966-07-05
Filing date: 1966-07-05
Publication date: 1969-04-15
Anticipated expiration: 1986-04-15

Description

April 1969 v. H. FOERSTERLING 3,438,477

PLATEN REVERSING MEANS FOR A PRINTING APPARATUS Filed July 5, 1966 1 POWER SOURCE b AUTOMATIC, INVENTOR.

E 59 T EA 53$ ERNON H. FOERSTERLING *64 so 2 BY 6 UN: $1M

Fig) ATTORNEYS" United States Patent U.S. Cl. 197-114 Claims ABSTRACT OF THE DISCLOSURE In a printing apparatus of the type including a platen for supporting a printing medium and means for driving the platen forwardly, means for reversing the platen in a step-by-step manner. The reversing means comprises first ratchet means arranged to move the platen in the reverse direction, second ratchet means arranged to stop movement of the platen in the reverse direction and electrically operated means for substantially simultaneously operating the first and second ratchet means to move said platen a predetermined amount in the reverse direction. Manually operated means is provided for energizing the electrically operated means and switch means is provided for deenergizing the electrically operated means when the platen is moved said predetermined amount, the switch means being responsive to movement of the electrically operated means. Preferably, circuit means is provided for automatically operating the electrically operated means, the circuit means being connected in parallel with the manually operated means and responsive to coded input means. Also, preferably, means for imparting a code index to a tape is provided, the circuit means being arranged to actuate the code index imparting means when the elec trically operated means is energized by the manually operated means.

The present invention relates to printing apparatus and the primary object of the invention is to provide a simple means for reversing a platen of a printing apparatus in a step-by-step manner.

A further object of the present invention to provide a platen reversing means for a printing apparatus of the type including a platen movably supported therein for supporting a printing medium thereon.

Another object of the present invention is to provide such a reversing means wherein a manually operated means or an automatic circuit means may be utilized to reverse the platen.

Still another object of the present invention is to provide, in such a reversing means, a first and second ratchet means operatively connected to said platen and an electrically operated means for operating said first and second ratchet means so as to move the platen a predetermined amount in the reverse direction.

Further objects of the present invention will become apparent as this specification proceeds.

FIG. 1 is a perspective view of a typical printing apparatus of the type which may utilize the platen reverse mechanism of the present invention;

FIG. 2 is a fragmentary perspective view of the platen reverse mechanism of the present invention; and

FIG. 3 is a side view of the ratchet wheels for driving a platen in a forward and reverse direction and the drive pawls cooperating with said ratchet wheels.

Generally speaking, the present invention resides in a printing apparatus of the type including a platen for supporting a printing medium and is a means for reversing the platen in a stepby-step manner. There is a first ratchet means operatively connected to the platen and arranged so as to move the platen in a reverse direction. A second ratchet means is also operatively connected to the platen and arranged so as to stop movement of the platen in the reverse direction. Electrically operated means are provided for operating the first and second ratchet means so as to move the platen a predetermined amount in the reverse direction. A manually operated means for energizing the electrically operated means is provided and a circuit means for automatically energizing the electrically operated means may be connected in parallel with the manually operated means. The circuit means is adapted to operate in response to a coded input means. There is a switch means responsive to movement of said electrically operated means so as to deenergize the electrically operated means when the platen is moved a predetermined amount in the reverse direction.

In a specific embodiment of the present invention, the aforementioned electrically operated means comprises solenoid means and linkage means. The linkage means is connected between the solenoid means and the aforementioned ratchet means.

Referring now to the drawing, the structure of an illustrative embodiment of the present invention can be visualized in conjunction with the following description.

Referring specifically to FIG. 1, it can be seen that a typical printing apparatus, indicated generally by the reference number 10, is illustrated. The printing apparatus 10 may typically be an electric typewriter, but may also be any type of business machine having a platen supported on a carriage and adapted to support a printing medium, such as paper. For purposes of illustration, how ever, the following description will be directed toward the provision of a platen reversing mechanism for an electric typewriter.

The printing apparatus 10, hereinafter referred to as the typewriter 10, is provided with a manually operated means 11 for actuating the platen reverse mechanism. The manually operated means, hereinafter referred to as the key 11, is disposed near the top and lefthand side of a keyboard, indicated generally by the reference number 12. There are

means

13 and 14 on the typewriter 10 for receiving

code tapes

15 and 16, respectively. In accordance with conventional practice, one of said means, for instance 14, is effective to impress a code upon the tape 16 as the typewriter 10 is operated, while the other of said means is effective to operate the typewriter 10 automatically to print out the information stored on a previously coded tape 15. The operation of the means 13 and 14- which correspond, respectively, to the means 23, 21 of the Davidson et al. Patent 2,832,455 issued Apr. 29, 1958, will be discussed further in conjunction with FIG. 2.

The balance of the typewriter 10 elements illustrated in FIG. 1 are typical of all typewriters of the character hereunder consideration and need not be discussed in this description.

Referring now to FIG. 2, the structure of an illustrative platen reverse mechanism, indicated generally as 17, can be discussed.

A platen 18 is mounted on a shaft 19 so as to be rotated thereby. There is a ratchet wheel 20 mounted on the shaft 19 so as to rotate the platen 18 in the direction of the arrow 21. There is a second ratchet wheel 22 mounted on the shaft 19, adjacent to the ratchet wheel 20, so as to rotate the platen 18 in the direction of the arrow 23 shown thereon.

The ratchet wheel 20 is normally used in typewriters of the type shown in FIG. 1 for advancing the platen step-by-step in a forward direction as the typewriter is operated. In accordance with the present invention, the ratchet wheel 22 is added to provide a means for reversing the direction of the platen 18.

There is a drive arm 24 arranged so as to ride on a cylindrical surface 22' in the space between the

ratchet wheels

29 and 22. The drive arm 24 has a pawl tooth 25 fastened thereto so as to drive the ratchet wheel 22 in the direction of the arrow 23 when the drive arm 24 is driven in the direction of the arrow 26. In most instances, gravity will hold the arm 24 in contact with surface 22'; but if desired spring means (not shown) maybe provided to bias said arm 24 resiliently to such contact.

The drive arm 24 is pivotally connected to the end of a first extension 27 of an L-shaped member 28. The L- shaped member 28 is pivotally mounted on a shaft 29 at a point where the two extensions of said member 28 meet. The shaft 29 is rigidly supported in the typewriter 10.

There is a stop pawl 30 pivotally mounted about the shaft 29 and adapted to engage the ratchet wheel 20 when actuated. A specific means for mounting the stop pawl 30 about the shaft 29 will be discussed in conjunction with FIG. 3.

There is a linkage, indicated generally by the reference number 31, connecting the end of the second extension 32 of the L-shaped member 28 to a lever 33 connected to the armature of a solenoid 34. The linkage 31 has a pivotal connection means 35 connected directly to the end of the extension 32 and a second pivotal connection means 36 connected directly to the armature lever 33. The pivotal connection means 35 has an internally threaded shank portion 37 for receiving a first threaded end 38 of a connecting bar 39. Similarly, the pivotal connection means 36 has an internally threaded shank portion 40 for receiving a second threaded end 41 of the connecting bar 39. The internally threaded

shank portions

37 and 40 and the threaded

ends

38 and 41 of the connecting bar 39 provide a means for adjusting the position of the drive arm 24.

There is a pair of spaced apart stop rings 42 and 43 independently adjustably fixed to the connecting bar 39, and spring means 44 is sleeved upon the connecting bar 39 and constrained between the stop rings 42 and 43. There is a link 45 having a first end sleeved on the bar 39 and resiliently supported intermediate the ends of the spring 44, and having a second end connected to an extension 46 of the stop pawl 30 by a pivotal connecting means 47. It can be seen that the pivotal connecting means 47 has an internally threaded shank portion 48 for receiving a threaded end 49 of the link 45. The internally threaded shank portion 48 and threaded end 49 are a means for determining the tension on the member 45 and, consequently, the holding power of the stop pawl 30. The link 45, therefore, is resiliently connected to the linkage 31 and pivotally connected to the stop pawl 30. Because of this resilient connection, the stop pawl 30 is resiliently engaged with the ratchet wheel 20 when the drive arm 24 is operated.

There is a spring means 50 connected between the pivotal connecting means 36 and a stationary portion 51 of the structure of the typewriter 10 so as to return the armature lever 33 to its normal position when the solenoid 34 is deenergized. In many solenoid structures, the spring return feature may be built into the solenoid.

The solenoid 34 has a pair of

terminals

52 and 53. The terminal 52 is connected directly to a first side of a normally-open switch 54 and a first side of an automatic reversing circuit 74. The terminal 53 is connected to a first side of a normally-closed switch, indicated generally by the reference number 55, and through said switch to a first side 56 of a power source. The second side 57 of the power source is connected directly to a second side of the automatic reversing circuit 74 and to a second side of the switch 54. There is a manually operated means, indicated generally by the reference number 58, for energizing the solenoid 34. In the illustrative embodiment shown in FIG. 2, the means 58 comprises a lever member 59 pivoted on a shaft 60, a button 61 on one end of the lever member 59 and an extension 62 on the opposite end for closing the switch 54. Thus, whenever the operator of the typewriter 10 presses the button 61 in the direction of the arrow 63, the extension 62 will move in the direction of the arrow 64 to close the switch 54, thereby energizing the solenoid 34 through the

switches

54 and 55.

The switch 55 is constructed and arranged so that movement of the armature lever 33 in the direction of the arrow 65 strikes the actuator arm 66 of the switch 55 to open the energizing circuit for the solenoid 34.

The automatic reversing circuit 74 is connected in parallel with the switch 54 and is electrically associated with the

means

13 and 14 so that a suitable code index will be impressed on the tape 16 whenever the button 61 is depressed, and so that the solenoid 34 will be energized whenever the requirement for such an energization is programmed into the coded tape 15. Therefore, the automatic reversing circuit 74 is a circuit means for automatically energizing the solenoid 34 and operates in response to coded input means. Specific circuits for providing an electrical output to operate a solenoid or for closing a circuit to permit current to fiow to the solenoid are well known in the art. For instance, a proper transistor having a base electrode adapted to receive inputs from a tape reader and an emitter-collector circuit connected between a power source and a solenoid will oper ate the solenoid whenever a sufficient biasing voltage is applied to the base electrode. Similarly a silicon controlled rectifier having a gate electrode adapted to receive inputs from a tape reader, an anode electrode connected to a power source and a cathode electrode connected to a solenoid will operate the solenoid whenever a sufficient current is applied to the gate electrode. Since such circuits are Well known in the art, it will not be necessary to describe an automatic reversing circuit, in detail, in this specification. See, for instance, the Bryce Patent 2,254,931 issued Sept. 2, 1941 showing a reader corresponding to means 13, which reader is connected to a work circuit by means of an amplifying circuit; the Dodge Patent 2,555,734 issued June 5, 1951 showing an automatic typewriter comprising a reader and the manner in which the reader is electrically connected to solenoidoperated keys; and the Prince Patent 2,897,267 issued July 28, 1959 showing a reader and an amplifier for connecting the reader to a relay.

Referring now to FIG. 3, a fragmentary side view of the platen reversing mechanism 17 can be discussed.

As stated previously the drive arm 24 is pivotally connected at the end of the first extension 27 of the L-shaped member 28. Specifically, and as shown in FIG. 3, the drive arm is pivotally mounted on a stud 67 extending from the extension 27 and is secured thereon by a snap ring 68.

The stop pawl 30 is adjustably mounted on a cam 69 which is rotatably mounted on the shaft 29. The cam 69 may be rotated with respect to the stop pawl 30 so as to adjust the position of said stop pawl 30 with respect to the ratchet wheel 20. There is a set screw 70 for securing the stop pawl 30 to the cam 69. The cam 69, therefore, is a cam means for determining the amount of travel of the platen 18 in the reverse direction.

There is a drive pawl 71 engaged with the ratchet wheel 20 so as to advance the ratchet wheel 20 in a forward direction when the pawl 71 is actuated. The drive pawl 71, therefore, is the conventional drive pawl for advancing the platen 18.

With the above description in mind, and by making reference to the drawing, the following operation analysis will serve to convey the functional details of the present invention.

The platen 18 is advanced, step-by-step, in the normal forward direction of the arrow 21 by means of the pawl 71 engaging and driving the ratchet wheel 20. The pawl 71 may be actuated by any number of techniques normally utilized in electric typewriters. However, in many cases, the operator of the typewriter will desire to reverse the platen 18, step-by-step, for a predetermined amount. If the typewriter 10 is of the type which may be automatically operated by a coded tape, the tape may contain coded instructions for reversing the platen 18.

When the operator desires to reverse the platen 18, she will press the button 61 to close the switch 54. When the switch 54 is closed, current can flow from the power source through the switch 54 to energize the solenoid 34, thereby rotating the armature lever 33 in the direction of the arrow 65. When the armature lever 33 strikes the actuator arm 66, the switch 55 is opened to deenergize the solenoid 34 and the spring 50 returns the armature lever 33 to its non-operated position.

When the solenoid 34 is energized to rotate the armature lever 33 in the direction of the arrow 65, the linkage 31 is moved in the direction of the arrow 72 to pivot the L-shaped member 28 in the direction of the arrow 73, thereby moving the drive arm 24 in the direction of the arrow 26. When the linkage 31 is moved in the direction of the arrow 72, the link 45, resiliently connected thereto, is also moved in the direction of the arrow 72 to engage the stop pawl 30 with the ratchet wheel 20, thereby stopping the reverse movement of the platen 18. The stop pawl 30 may be adjusted on the cam 69 so as to permit the advancement of one or more teeth of the ratchet wheel 20.

The key 58 is a manual means for reversing the platen one step at a time. That is, the button 61 must be pressed each time that the platen 18 is reversed manually.

The platen reversing mechanism 17 of the present invention is particularly advantageous because it can be energized by an automatic reversing circuit 74 cooperating with a coded tape receiver means 13 and 14 or the like. If the reversing mechanism 17 was purely mechanical, electrical outputs as provided by the automatic reversing circuit 74 could not be utilized to reverse the platen 18.

An electric typewriter having a platen reverse mechanism, such as described supra, can ideally be used to draw figures, such as are used to depict chemical formulae, and to type information at any point on a chart in any sequence. With the automatic reversing circuit and coded tape receiving means, discussed supra, the typewriter can be programmed to perform the above-mentioned functions automatically. It may also be used to fill out forms or form formats having a sequence that does not correspond to the sequence of the data contained in the tapes.

In some electric typewriters of the type having a coded tape receiving means, manual actuation of the platen reverse mechanism of the present invention not only reverses the platen, but causes a code to be punched or otherwise placed in a tape so that the manual operation may be repeated automatically. This, of course, is the theory of operation of the Flexowriter apparatus discussed in the aforementioned Davidson et al. Patent 2,832,455.

The solenoid 34, linkage 31, linkage 45 and L-shaped member 28 are an electrically operated means for operating the pawl 25 and stop pawl 30. If the

ratchet wheels

20 and 22 and the pawls associated therewith are considered, broadly, as ratchet means operatively connected to the platen 18, the solenoid 34, linkage 31, linkage 45 and L-shaped member 28 are an electrically operated means for operating said ratchet means.

I claim as my invention:

1. In a printing apparatus of the type including a rotatably mounted platen for supporting a printing medium and means for driving the platen forwardly, means for driving the platen reversely in a step-by-step manner, the last-mentioned driving means comprising a first ratchet :wheel mounted on a common shaft with said platen, said first ratchet wheel being arranged to rotate said platen in the forward direction, a second ratchet wheel mounted on said shaft adjacent to said first ratchet wheel, said second ratchet wheel being arranged to rotate said platen in the reverse direction, first pawl means for engaging and driving said second ratchet Wheel, second pawl means for engaging and stopping said first ratchet wheel then said platen is rotated a predetermined amount in the reverse direction, electrically-operated means effective, when energized, to shift said first pawl means in a direction afiirmatively to engage and move said second ratchet wheel in the reverse direction and substantially simultaneously aifirmatively to move said second pawl means into stopping engagement with said first ratchet wheel, manually-operated switch means for connecting said electrically-operated means to a power source, thereby to energize said electrically-operated means, and second switch means for disconnecting said electrically-operated means from such a power source, said second switch means being responsive to movement of said electrically-operated means in response to energization thereof.

2. In a printing apparatus of the type including a rotatably mounted platen for supporting a printing medium and means for driving the platen forwardly, means for driving the platen reversely in a step-by-step manner, the last-Said driving means comprising a first ratchet wheel mounted on a common shaft with said platen and arranged to rotate said platen in a forward direction, a second ratchet wheel mounted on said shaft and arranged to rotate said platen in a reverse direction, a first pawl for engaging and driving said second ratchet wheel and said platen in said reverse direction, a second pawl for engaging and stopping said first ratchet wheel when said platen is rotated a predetermined amount in said reverse direction, a solenoid operatively connected to said pawls and effective, upon energization, to move said first pawl affirmatively to drive said second ratchet wheel and substantially simultaneously to move said second pawl to engage and stop said first ratchet wheel, a manually-operated switch for connecting said solenoid to a power source, thereby to energize said solenoid, and a second switch for disconnecting said solenoid from such a power source, thereby to deenergize said solenoid, said second switch being responsive to movement of said solenoid in response to energization thereof.

3. The invention of claim 2 in which the operative connection between said solenoid and said first pawl comprises a bell crank pivotally mounted on said apparatus, said first pawl being drivingly connected to one arm of said crank and said solenoid being drivingly connected to the opposite arm of said crank, whereby, when said solenoid is energized, said crank is pivoted to drive said first pawl.

4. The invention of claim 2 including a cam journal mounted on said printing apparatus, said second pawl being adjustably mounted on said cam, thereby to determine the permissible amount of movement of said platen in said reverse direction, the operative connection between said second pawl and said solenoid including resiliently yieldable means, whereby, when said solenoid is energized, said second pawl and said cam are pivoted about the journal axis of said cam.

5. The invention of claim 3 including a cam journal mounted on said printing apparatus, said second pawl being adjustably mounted on said cam, thereby to determine the permissible amount of movement of said platen in said reverse direction, a first linkage for connecting the armature of said solenoid to said opposite arm of 7 8 said bell crank, and a second linkage having a first end 1,181,958 5/1916 Roberts 197-114 connected to said second pawl and a second end resilient- 1,571,519 2/ 192 6 Gabrielson 197-114 1y connected to said first linkage. 1,821,099 9/1931 Kurowski 197-114 2,453,282 11/1948 Thierne 197-114 References Cited 5 2,476,917 7/1949 Ruben 197-114 2,555,734 6/1951 Dodge 197-20 UNITED ST ATES PATENTS 2,633,828 4/1953 Adkins et a1 197 114 X 5 9 9/1951 Rltz 197149 2,791,311 5/1957 Yerks et a1. 197- 114 2,710,045 2/ 1955 Madsen 19791 2,832,455 4/1958 Davidson et a1. 197-114X 924,096 6/1909 McLaughlin 197-114 954,637 4/1910 Kurowski 197 114 X ERNEST T. WRIGHT, Primary Examiner.