US3704667A

US3704667A - Printing unit

Info

Publication number: US3704667A
Application number: US134070A
Authority: US
Inventors: James R Moss
Original assignee: NORTRON Inc
Current assignee: NORTRON Inc
Priority date: 1971-04-14
Filing date: 1971-04-14
Publication date: 1972-12-05
Anticipated expiration: 1989-12-05

Abstract

A character printing unit having an inertia driven hammer assembly, the unit which including a rotating non-circular shaft controlled by a clutch and a brake, the clutch, when energized coupling a drive motor to the shaft. The shaft is adapted to drive a high speed rotary inertia element through a gear mounted on the shaft, the inertia element driving the hammer to print a character upon braking of the shaft element.

Description

United States Patent Moss 2 [451 Dec. 5, 1972 [54] PRINTING UNIT [72] Inventor: James R. Moss, Mt. Clemens, Mich.

[73] Assignee: Nortron, lnc., Ann Arbor, Mich.

[221 Filed: April 14, 1971 [21] Appl. No.: 134,070

Related US. Application Data [63] Continuation of Ser. No. 808,821, March 20, 1969,

abandoned.

[52] U.S.Cl ..l0l/93 C, 74/1255, 197/53 [51] Int.Cl ..B41j7/44,B41j23/10 [58] FieldofSearch ..101/93RC;178/34;74/l12, 74/125.5

[56] References Cited UNITED STATES PATENTS 1,971,858 8/1934 Knutsen ..10l/93X 75km? r/x112 j}? flmydzmlr.

i (Pf/1x1? 2,895,411 7/1959 Demer et al..... ..l0l/93 2,897,752 8/1959 Malmros et aL. ...10l/93 3,128,694 4/1964 Kittler ...101/93 3,128,696 4/1964 Hoffman ..101/93 3,185,283 5/1965 Spitsbergen et a1. ..10l/93 X 3,232,402 2/1966 Koenen et al ..74/l25.5 X

Primary Examiner--Clyde l. Coughenour Attorney-Harness, Dickey and Pierce [5 7] ABSTRACT 17 Claims, 6 Drawing Figures PRINTING UNIT This application is a continuation of Ser. No. 808,821 filed Mar. 20, 1969, now abandoned.

BACKGROUND AND SUMMARY OF THE DEVELOPMENT which utilizes a'high speed inertia member to actuate lo the hammer of the unit upon correlation of the position of the character mounting assembly with the platen. While the following specification will be couched particularly in terms of a printing unit, it is to be understood that the invention is equally applicable to other character recording or coded information units, such as a punch unit, having a character recording mechanism and a recording and nonrecording cycle.

In the prior art character printing systems it has been the practice to actuate the print mechanism by means of springs, solenoids or other like devices which generally start from a rest position and are actuated or energized to impart mechanical energy to the hammer. These systems, while being satisfactory for low speed operation, are not particularly adapted to the accuracy FIG. 2 is a side view of the character printing unit of FIG. 1;-

FIG. 3 is a perspective view illustrating certain principles of the present invention, including a portion of the control circuit for the character printing unit;

FIG. 4 is a cross sectional view on a plane through the main shaft of the character printing unit and particularly illustrating the details of the drive and inertia gear element;

FIG. 5 is a cross sectional view illustrating the details of one preferred form of 90 drive for driving the character disc of a character printing unit; and

FIG. 6 is a graph illustrating a shaft revolutions versus time relationship for a typical printing cycle.

Referring now to the drawings, particularly to FIGS. 1 and 2 thereof, there is illustrated one form of character printing unit 10 incorporating the principles of the present invention. The unit 10 is generally of the required in high speed printing operation, do not have the required quick recovery of the hammer and generally have the characteristic that the inertia of the system works against the desired result of actuating the hammer.

Accordingly, it is one object of the present invention to provide an improved dynamic energy producing assembly for use in connection with a character recording unit.

It is another object of the present invention to provide an improved energy generating apparatus for a character recording unit which eliminates springs and solenoids from the energy transmitting assembly for the mechanism of a character recording unit.

It is a further object of the present invention to provide an improved character print assembly which incorporates a high inertia rotating device to impart energy to the print hammer when it is desired to print a character. I

It is a further object of the present invention to pro vide an improved impulse system for a print hammer which incorporates the feature of a quick recovery of the hammer after the print cycle.

It is still a further object of the present invention to provide an improved system for actuating a hammer which has a high speed characteristic.

It is still another object of the present invention to provide an improved inertia impulse system for imparting energy to a print hammer which is extremely accurate at high printing speeds.

It is still a further object of the present invention to provide an improved print hammer actuating mechanism which is inexpensive to manufacture, simple to incorporate and accurate in use.

Further objects, features and advantages of this invention will become apparent from a consideration of the following description, the appended claims and the accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a top view of a writing unit incorporating the features of the present invention;

conventional type which includes a platen 12 adapted to be driven by a line advance stepping motor 14 connected to the platen 12 by means of a line advance belt 16. The belt 16 is driven by the motor through a first pulley l8 and is connected to the platen by means of a second pulley 20. The motor 14 is of the stepping type which is advanced in response to a pulse being fed thereto,. the timing of the pulse being more fully described in conjunction with the description of FIG. 6. Paper is fed to the platen mechanism from a paper storage bin 24 adapted to receive a plurality of continuous sheets of paper 26, the paper being fed over a first guide roller 28, under a second guide roller 30, and across thetop of the platen 12. Thus, a succession of pulses being fed to the stepping motor 14 will advance the paper through the machine in a series of incremental steps which are related to the spacing between the lines of print on the paper.

Relative horizontal movement between the print mechanism, to be described in conjunction with FIGS. 3 to 5, and the paper on the platen is accomplished by means of a character advance assembly 34 which includes a horizontal character advance stepping motor 36, a belt 38 which is driven by the stepping motor 36 and a drive mechanism (not'shown) which is attached to a print disc assembly 40. The stepping motor is fed successive pulses in response to each individual printing or spacing operation to advance the print mechanism 40 relative to the platen 12 in a step-bystep motion. It is to be understood that this in only one form of print mechanism and other print mechanisms may be utilized such as the type of machine which includes an assembly for advancing the platen relative to the print assembly 40. The input to the system may be provided by means of a keyboard 46 or by electrically feeding signals to an input circuit (not shown) within the unit 10. Also, the unit is mounted on a stand which includes a main pedestal 48 and a plurality of feet elements 50.

Referring now to FIG. 3, there is illustrated an exploded perspective view schematically illustrating a hammer drive mechanism in accordance with the present invention. Particularly, the print mechanism 40 includes a print disc 50 having a plurality of individual fingers 52 formed around the periphery of a central hub portion of the disc, the individual fingers being adapted to carry the characters to be printed on a circumferential outer end of each finger.

A hammer element 56 is mounted adjacent the disc 50 in position to strike the ends of the fingers 52 and is actuated in response to a control system which senses when the selected character finger 52 is properly positioned under the hammer or will be properly positioned under the hammer when the hammer strikes the disc 50. In the preferred embodiment, the hammer is actuat'ed through an inertia assembly 60 which is mounted on a shaft 62 driven from an induction motor 64 through a clutch assembly 66. The induction motor 64 is constantly running in a direction indicated by the arrow on a pulley member 68, the motor64 being coupled to the clutch member 66 by means of the pulley 68, a belt 70 and a second pulley member 72. The clutchassembly 66 is preferably of the magnetic particle type which is energized to engage or couple the motor 64 to the shaft 62 when the assembly is not in a print cycle. When the selected character is to be printed, the clutch 66 is deenergized to decouple the shaft 62 from the motor and a brake assembly 76 is energized to stop the shaft member 62 at the selected point. The energy to drive the hammer 56 and the disc 50 is transferred from the shaft 62 by means of the drive assembly 60 during the non-printing portion of direction indicated. The inertia gear 80 is directly coupled to the hammer member by means of-a pin 84 so that the motion of the inertia member 84 relative to the gear 78, when the print portion of the cycle is initiated, is imparted to the hammer 56. The hammer 56 is rotatably mounted relative to the shaft 62 to permit the hammer 56. to have an angular movement relative to the shaft 62 during the print portion of the cycle.

The disc member 50 is driven by a right angle drive which includes a first bevel gear member 86 fixedly mounted directly on the shaft 62 for rotation therewith and a second bevel gear element 88 which is mounted on the disc 50. Thus, the rotation of the shaft 62 is imparted to the disc 50 by means of the coupling between the

bevel gears

86, 88, and the disc 50 is synchronously coupled to the rotation of the shaft 62.

The position of the disc relative to a fixed position is sensed by means of a sensing element 90 which may take any form. For example, a magnetic element may be positioned to sense the passage of the fingers 52 past the face of the sensing element 90 and generates a series of pulses in response to the number of fingers which pass element 90. These pulses are fed to a comparator circuit 94 which compares the count of the pulses generated in accordance with the relative positions of the selected character with respect to a fixed position on the disc, this signal being compared to the selected character as fed to the comparator circuit by means of an input conductor 96. Also, a ready signal is provided the comparator 94 by means of an input conductor 98. When coincidence occurs between the selected character and the sensed character, a pulse is generated on an output conductor 100 which causes deenergization of the clutch 66 and energization of the brake 76 by means of conductors 102, 104.

The output signal from the comparator circuit also supplies a pulse tothe timer circuit by means of a conductor 112, the timer circuit being adapted to provide output pulses to advance the character stepping motor connected to conductor 114.

Referring now to FIG. 4, there are illustrated further details of the system of the present invention. As was discussed in conjunction with FIG. 3, the shaft 62 directly drives the gear 78, the gear78 in turn driving the planetary gear 80 which is directly coupled to the hammer 56 by means of the pin84. The hammer is adapted to strike a character embossed bead disposed between the struck portion of the disc 50 and the paper supported on the platen 12. A suitable resilient elementl22 is disposed between a surface 124 of the hammer and a mounting member 126 to simulate thicknesses of paper. In this way the striking force of the hammer against the paper is controlled to provide a uniform striking force irrespective of the number of sheets of paper supported on the platen 12.

Also, an adjustable pin member 128 is provided at one end of the hammer. to adjustthe back or rest 'position of the hammer 56 during the non-print portion of the cycle. It will be noted, with the rotation as indicated in FIGS. 3 and 4 that the planetary gear tends to pull the hammer 56 away from the paper and platen 12. When the shaft 62 is stopped, the inertia of the gear 80, due to the rotation in the direction indicated, will cause the hammer 56 to rotate about the shaft 62 and strike the disc 50. In this way the character embossed on portion 120 is printed on the paper supported on platen 12.

FIGS. 4 and 5 also illustrate the details of the right angle drive utilized to impart synchronous rotary motion to the disc 50 from the rotation of the shaft 62. As was stated above, the shaft 62 mounts a bevel gear 86, the gear 86 being in mating engagement with'a second bevel gear 84. Thus, the rotary motion of the shaft 62 is imparted to a second shaft 130 but at right angles thereto. The gear 84 includes a necked down portion which non-rotatably supports the disc 50 and a support member 132 on which the disc member 50 is mounted. The support member 132 and disc 50 are non-rotatably mounted on thegear 84, which in turn is non-rotatably mounted relative to the shaft 130. The shaft 130 is rotatably supported by means of a pair of

roller bearing assemblies

136, 138, which, in addition to taking up any radial forces on the shaft 130, also supply thrust resisting forces by means of a washer mounted at the end thereof.

FIG. 5 particularly illustrates a rotary mounting assembly for providing radial support for the rotating shaft 62. The assembly includes an outer housing 152 which mounts a further pair of bearing

assemblies

154, 156. The housing 152 is supported on the main character printing unit.

With the system of the present invention, the printing disc is driven by the shaft 62 at a speed which is greater than that allowable for safe no-smear printing. However, the system is caused to decelerate by the disengagement of the clutch member 66 and the engagement of the brake 76, particularly causing the deceleration of the print disc 50. Also, during this deceleration period, the inertia of the planetary gear 80 will cause a reverse momentum in the gears to drive the hammer 56 on to the character printing disc. The reacceleration of the system then causes the retraction of the hammer away from the character printing disc.

FIG. 6 illustrates a typical speed versus time curve for the system of the present invention, and particularly for the disc member 50. It is seen that during the idle portion of the cycle, the speed of the disc exceeds the safe level for no-smear printing. Upon the energization of the brake and deenergization of the clutch, the system, with a I predetermined lag, will start to decelerate to a point below the safe printing level. At this time, the hammer strikes the character printing disc at the print point illustrated in FIG. 6, to cause the character to be printed on the paper supported by platen 12. The graph of FIG. 6 also illustrates a timing circuit multivibrator pulse which is energized in response to the start of a print cycle. Simultaneously with the printing of the character, the multivibrator circuit times out to reenergize the clutch and deenergize the brake, causing the system to reaccelerate to the idle level. Also, at the trailing edge of the multivibrator pulse, the print unit advance pulse is generated by the timing circuit to step the character advance stepping motor.

While it will be apparent that the preferred embodiment of the invention disclosed is well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

What is claimed is:

1. In a character recording unit having a character recording and nonrecording cycle, and a character recording mechanism including a movable recording member, and energy storing and delivering system for imparting energy to the recording mechanism during the recording cycle of the character recording unit, the improvement comprising means for imparting stored rotary inertia energy to the movable recording member by a direct connection between the movable recording member and the inertia storage means including rotary inertia storage means supported by the movable member of the recording mechanism for movement therewith both during the non-recording and recording cycles, motive means connected to said inertia storage means for rotating the storage means during the nonrecording cycle, and delivering means for imparting the stored rotary inertia energy to the recording mechanism through the connection between the movable member and the rotary inertia storage means during the print cycle.

2. The improvement of claim 1 wherein the character recording mechanism is a print mechanism including a print and non-print cycle and said movable recording member includes a hammer.

3. The improvement of claim 1 wherein said delivery means includes a rotatable element driven by said motive means, said element being coupled in driving engagement with said storage means at least during the nonrecording cycle.

4. The improvement of claim 3 wherein said motive means includes a rotating motor, said motor being energized during both the recording and nonrecording cycles.

5. The improvement of claim 1 wherein said motive means includes a rotating motor, said motor being energized during both the recording and nonrecording cycles.

6. The improvement of claim 5 wherein said motive means includes a shaft and a second gear nonrotatably mounted on said shaft, said motor being coupled to said shaft by a clutch.

7. The improvement of claim 6 wherein said rotary inertia storage means includes a first gear and said delivery means includes a brake operatively coupled to said shaft, said brake being energized and said clutch disengaged during said print cycle.

8. The improvement of claim 7 wherein said second gear is decelerated during the cycle by said brake and said first gear element rolls on the periphery of said second gear element whereby the axis of rotation of said first gear at least partially orbits the axis of rotation of said second gear in a first direction to advance the print mechanism.

9. The improvement of claim 8 wherein said second gear is accelerated at the end of said print cycle by said motor and said clutch and said first gear element rolls on the periphery of said second gear element whereby said first gear axis orbits said second gear axis in an opposite direction to said first direction to retract the print mechanism.

10. The improvement of claim 1 wherein the rotary inertia storage means is mounted on the movable recording member for movement therewith.

11. The improvement of claim 10 wherein the movable recording member is-pivotally mounted for pivotal movement of the movable recording member and the rotary inertia storage means, the stored rotary inertia being at least in part transferred to the pivotally mounted movable recording member by pivotal movement thereof to effect recording during the recording cycle.

12. The improvement of claim 11 wherein the movable recording member includes a print hammer and wherein the character recording mechanism is a print mechanism including a print and non-print cycle.

13. The improvement of claim 11 wherein said motive means includes a rotating motor, said motor being energized during both the recording and nonrecording cycles and said first and second direct drive means include first and second gear elements, respectively.

14. The improvement of claim 13, wherein said motive means includes a shaft and said second gear element is non-rotatably mounted on said shaft, said motor being coupled to said shaft by a clutch.

15. The improvement of claim 14, wherein said delivery means includes a brake operatively coupled to said shaft, said brake being energized and said clutch disengaged during said print cycle.

16. The improvement of claim 15, wherein said second gear is decelerated during the cycle by said brake and said first gear element rolls on the periphery of said second gear element whereby the axis of rotation of said first gear at least partially orbits the axis of rotation of said second gear in a first direction to advance the print mechanism.

17. The improvement of claim 16, wherein said second gear is accelerated at the end of said print cycle by said motor and said clutch and said first gear element rolls on the periphery of said second gear element whereby said first gear axis orbits said second gear axis in an opposite direction to said first direction to retract the print mechanism. I

Claims

11. The improvement of claim 10 wherein the movable recording member is pivotally mounted for pivotal movement of the movable recording member and the rotary inertia storage means, the stored rotary inertia being at least in part transferred to the pivotally mounted movable recording member by pivotal movement thereof to effect recording during the recording cycle.

17. The improvement of claim 16, wherein said second gear is accelerated at the end of said print cycle by said motor and said clutch and said first gear element rolls on the periphery of said second gear element whereby said first gear axis orbits said second gear axis in an opposite direction to said first direction to retract the print mechanism.