US3292531A

US3292531A - Printing hammer arrangement

Info

Publication number: US3292531A
Application number: US510409A
Authority: US
Inventors: Mutz Gerhard
Original assignee: Kienzle Apparate GmbH
Current assignee: Digital Kienzle Computersysteme GmbH and Co KG
Priority date: 1964-11-28
Filing date: 1965-11-29
Publication date: 1966-12-20
Anticipated expiration: 1983-12-20
Also published as: FR1454319A

Description

Dec. 20, 1966 u'rz 3,292,531

PRINTING HAMMER ARRANGEMENT Filed Nov. 29, 1965 Patented Dec. 20, 1966 3,292,531 PRINTING HAMMER ARRANGEMENT Gerhard Mutz, Villingen, Germany, assignor to Kienzle Apparate G.m.b.H., Villingen, Black Forest, Germany Filed Nov. 29, 1965, Ser. No. 510,409 Claims priority, application Germany, Nov. 28, 1964, K 54,658 8 Claims. (Cl. 10193) The present invention relates to a printing hammer arrangement for a line printer, and more particularly to printing apparatus in which printing hammers cooperate with a type carrier, such as a type barrel or type rod to print one line of characters,'while a complete set of types passes at a printing station.

It is known to select the printing hammers by electromagnetic means, and to move the printing hammers to a printing position by mechanical drive means, such as a toothed drive roll.

It is one object of the invention to improve known printing hammer arrangements for line printers, and to provide a very rapidly operating line printer, comprising only a few movable parts.

Another object of the invention is to provide a printing hammer arrangement in which the printing hammer will move only once to the printing position, and cannot be actuated a second time if the electromagnetic means is still energized when the printing hammer returns to its position of rest.

Another object of the invention is to provide a printing hammer arrangement in which the printing hammers are not subjected to a hard blow by the toothed drive wheel.

Another object of the invention is to provide a printing hammer arrangement in which the printing hammers are angularly movable when inoperative, but are reliably guided to a printing position.

Another object of the invention is to provide a quietly operating printing hammer arrangement.

With these objects in view, the present invention relates to a printing hammer arrangement for a line printer in which the printing hammers cooperate with a type carrier. One embodiment of the invention comprises a printing hammer cooperating with the type carrier; supporting means supporting the printing hammer for movement between an inoperative position and a printing position, and also for movement in the inoperative position between a position of rest and an actuated position; actuating means, preferably electromagnetic means, for moving the printing hammer from the position of rest to the actuated position; drive means, preferably a toothed drive roll engaging the printing hammer in the actuated position and moving the same to the printing position; and restoring means, preferably two springs acting in transverse directions, for returning the printing hammer from the printing position to the position of rest.

The electromagnetic actuating means includes an armature serving as selector member and acting on a thin wire to bend the same to a position engaging the printing hammer so that the same is moved from the position of rest to the actuated position in which it is engaged by the toothed drive roll. One spring of the restoring means urges the printing hammer to return from the printing position to the inoperative position, and another spring of the restoring means urges the printing hammer in a second transverse direction to return the printing hammer from the actuated position to the position of rest. The second spring is preferably a leaf spring, and moves the printing hammer away from the drive roll as soon as the printing hammer separates from the drive roll.

In the preferred embodiment of the invention, the printing hammer has an elongated transverse projection engaged by the toothed drive roll, and this projection is slightly resilient so. that no hard blow is exerted by the drive roll on the printing hammer, and the acceleration of the printing hammer is gradual. As compared with known constructions in which resilient teeth are provided on the drive roll, the construction of the invention has the advantage that a fewer number of resilient parts is required. Furthermore, a broken projection on a printing hammer is easily repaired by replacing the printing hammer, while repair of the printing roll when a tooth of the same breaks is expensive and difficult.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. la is a fragmentary schematic side elevation, partially in section, and illustrating one embodiment of the invention in a position of rest;

FIG. 1b is an elevation corresponding to FIG. 1a' but illustrating the device in an actuated position;

FIG. 10 is an elevation corresponding to FIGS. 1a and 1b, and illustrating the device in the printing position; and

FIG. 1d is an elevation corresponding to FIGS. 1a to la and illustrating the device in another operational position.

Referring now to the drawings, a rotary type carrier 1 is driven in the usual manner to rotate in the direction of the arrow to move types on the periphery thereof successively into and out of a printing area in which a line portion of a paper web 8 is located. A row of printing hammers 2, of which only one is visible in the drawing, cooperates with the type carrier 1 to press the paper web in the printing position shown in FIG. 10 against the respective type.

The forward ends of the printing hammers 2 are guided between a pair of

guide members

3, 4, which are cylindrical so that the printing hammers can individually turn between the position of rest shown in FIG. 1a, and the actuated position shown in FIG. lb in which an elongated transverse coupling projection 22 projects into a recess between the peripheral teeth of a drive roll 21. In the position shown in FIG. la, a first stop 5 stops movement of the printing hammer in a position of rest, and a second stop 7 stops movement of the printing hammer in the actuated position shown in FIG. 1b.

In the positions shown in FIGS. 1a and 1b, the printing hammer is inoperative and spaced from the type carrier 1, but due to the rotation of power roll 21, a printing hammer in the actuated position of FIG. 1b is driven toward the type carrier 1, and during such movement the printing hammer is guided by the pair of guiding

members

3, 4 so that the paper web 8 is accurately pressed against a type face of type carrier 1.

A spring 9 is secured to a projection of each printing hammer 2 and urges the same to move from the printing position to the position of rest in which the rear end of the printing hammer abuts an elastic damping cushion 11 which is mounted in a stationary support 10. A leaf spring 16 is also secured to support 10 and has a portion resiliently engaging the rear end portions of the printing hammers in the inoperative and printing positions and urging all hammers to move out of engagement with the teeth of drive roll 21 until stopped by stop 5. During movement of a printing hammer to the printing position, the rear end portion of the printing hammer slides on leaf spring 16. During movement of a printing hammer in 3 the opposite direction, the printing hammer slides on stop 5 and leaf spring 16.

Support carries a pair of

holding members

12 and 13, and a comb-shaped leaf spring 14. A series of spring wires is mounted between

holding members

12 and 13 and each spring wire 15 has a curved rear end portion bent about hold-ing member 13 and pressed against the same by leaf spring 14. The forward end of each spring wire 15 has a transversely bent end portion projecting toward the corresponding printing hammer 2 above and spaced from the rear end of the same.

Each printing hammer 2 and spring wire 15 is associated with an electromagnetic selector means including a core and winding 17, and a movable armature mounted on a pivot 19 on support 10 and having a selector portion 18 which is urged by the respective spring wire 15 into abutment with a fixed stop 20. When an electromagnetic means 17 'is energized, the armature is attracted, and selector member 18 bends the spring wire 15 to the position shown in FIG. 1b in which the spring wire abuts a fixed stop 12 on support 16. At the same time, the bent-over end portion of the spring wire engages rear end of the printing hammer and moves then the same from the position of rest toward the actuated position shown in FIG. 1b in which leaf spring 16 abuts stop 7. At the same time, the elongated projecting portion 22 of the respective printing hammer 2 moves into a recess between adjacent peripheral teeth of drive roll 21, which is driven in synchronism with the type carrier 1.

Since the pitch of the teeth of the drive roll 21 corresponds to the pitch of the types on type carrier 1, any angular movement of the drive roll 21 over an angle corresponding to the angular spacing of two teeth, re sults also in angular displacement of the type carrier for the angle at which two types are spaced.

The series of electromagnetic means 17, 18 is controlled by impulses which arrive at timed intervals corresponding to the position of the types of the type carrier, but within the time period corresponding to one revolution of the type carrier, so that each electromagnetic means 17, 18 is energized when selected and desired type moves into the printing area associated with the respective printing hammer, so that an entire line is printed of different characters during one revolution of the printing type carrier.

At the beginning of the operation, all printing hammers 2 are in the position of rest shown in FIG. 1a in which the printing hammers abut stop 5 under the action of leaf spring 16, and abut the resilient cushion 11 under the action of spring 16. The elongated projection 22 is located spaced from drive roll 21, and the forward end portion of each spring wire 15 is located spaced a small distance above the rear end of the respective printing hammer which is possible since electromagnetic means 17 is not energized.

When an electromagnetic means 17 is energized by a command impulse, the respective selector member 18 is turned in counterclockwise direction so that the respective spring wire is bent to assume the position shown in FIG. lb whereby selector member 18 is coupled with the respective printing hammer 2 and turns the same in clockwise direction while bending the spring 16 until the same abuts stop 7.

The printing hammer 2 is still inoperative, but has been moved by the

actuating means

17, 18, 15 to an actuated position in which its elongated projection is located in a recess between a pair of teeth of drive roll 21 so that the printing hammer is driven toward the left out of the inoperative position shown in FIGS. la and 1b toward the printing position shown in FIG. 1c.

Guide members

3 and 4 permit the angular movement of the printing hammer from the position of rest of FIG. la to the actuated position of FIG. lb, but guide the printing hammer :during movement to the printing position, and assure that the forward end of the printing hammer cooperates precisely with a type face of the type carrier 1 located in the printing area.

During the movement of the printing hammer toward the printing position, projection 22 is released by the respective drive tooth of power roll 21, so that the printing hammer is no longer connected with drive wheel 21 when arriving in the printing position of FIG. 1c. Spring 16 urges the printing hammer to turn in counterclockwise direction for moving projection 22 away from the power roll 21. Each printing hammer 2 has a projection 2' with a slanted camming face located in the region of a stationary guide 6, but spaced from the same in the position of rest of the printing hammer. In the actuated but inoperative position of the printing hammer shown in FIG. lb, the forward end of the camming face is located in the proximity of guide 6. When drive roll 21 drives the printing hammer toward the printing position, guide 6 acts on the slanted camming face of projection 2 to turn the printing member out of the actuated position connected with the drive roll to the position shown in FIG. 10 in which the printing hammer abuts stop 5 under the action of spring 16 which participates in angularly displacing printing hammer 2 out of the actuated position shown in FIG. lb.

Since printing hammer 2 already abuts stop 5 before arriving in the printing position, printing hammer 2 moves perpendicularly to the periphery of the type carrier 1 during the last part of its stroke toward the printing position so that the end face of the printing hammer is parallel to the paper web 8. The position of stop 5 and the slanted camming face of projection 2 may be so designed that the type carrier 1 takes along the forward end portion of the printing hammer 2 in the printing position to turn the printing hammer a very small angle until it abuts stop 5. Such extremely short movement of the printing hammer with the rotating type carrier produces a particularly clear imprint since the type and the end face of the printing hammer move at the same speed during the short time in which the imprint is being made.

Directly after the imprint spring 9 retracts the printing hammer which slides along leaf spring 16 and stop 5 toward the inoperative position. It is immaterial whether electromagnetic means 17 is energized or not, since spring 16 holds the printing hammer in a position in which its projection 22 cannot be engaged by the teeth of the power roll.

If electromagnetic means 17 is still energized, the transverse end portion of spring wire 15 is located between the rear end face of printing hammer 2 and the elastic cushion 11, and as soon as the electromagnetic means 17 is deenergized, spring wire 15 will raise selector member 18 and resiliently return to its normal position shown in FIG. la so that spring 9 will pull printing hammer 2 to its position of rest abutting cushion 11 as shown in FIG. la.

If the electromagnetic means 17 is deenergized when the printing hammer is returned by spring 9, the rear end face of the printing hammer will immediately abut elastic cushion 11.

The cushion 11 serves as clamping member to avoid dangerous rebounding of hammer 2. The projection 22 is comparatively long so as to be somewhat resilient so that projection 22 resiliently yields under the impact of the respective drive tooth of drive roll 21, resulting in a more gradual acceleration and in a quiet operation.

From the above description it will be apparent that guiding

members

3, 4, stops 5, and 7, support 10 and cushion 11, constitute supporting means permitting the printing hammer to move between the inoperative position shown in FIGS. la, 1b, 1d, and the printing position shown in FIG. 10, and also permit the printing hammer to angularly move in another direction between the position of rest shown in FIG. la and the actuated position shown in FIG. 1b. Electromagnetic means 17 with selector member 18 and spring wire 15 constitute actuating means for moving the printing hammer from the position of rest to the actuated position and the spring wire 15 serves as resilient coupling member between selector member 18 and printing hammer 2.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of printing hammer arrangements differing from the types described above.

While the invention has been illustrated and described as embodied in printing hammers which are angularly turnable to and from an actuated position cooperating with a drive means, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. Printing hammer arrangement for a line printer comprising, in combination, type carrier means movable for placing types successively in a printing area; a printing hammer cooperating with said type carrier means; supporting means including a pair of guide members located on opposite sides of said printing hammer for supporting the same for forward movement between an inoperative position and a printing position in which a part thereof is located in said printing area, and also for turning movement in said inoperative position between a position of rest and an actuated position; first and second stop means for stopping said turning movement of said printing hammer in said position of rest and said actuated position, respectively; actuating means. for turning said printing hammer from said position of rest to said actuated position; drive means engaging said printing hammer in said actuated position for moving the same forward to said printing position; and restoring means for returning said printing hammer from said printing position to said position of rest.

2. A printing hammer arrangement according to claim 1 wherein said drive means includes a rotary drive roll having drive teeth; and wherein said printing hammer has an elongated projection projecting toward said drive roll spaced from the same in said position of rest, and being engaged by a drive tooth of said drive roll in said actuated position so that said printing hammer is driven toward said printing position, said projection being constructed to provide an elastic connection between said drive roll and said printing hammer.

3. A printing hammer arrangement according to claim 1 wherein said supporting means includes an elastic abutment engaged by said printing hammer in said inoperative position when returned from said printing position by said restoring means.

4. A printing hammer arrangement according to claim 1 wherein said restoring means include a first spring for urging said printing hammer from said printing position to said inoperative position, and a second spring stressed by said printing hammer in said actuated position and urging said printing hammer out of engagement with said drive means.

5. A printing hammer arrangement according to claim 1 wherein said restoring means include a first spring for urging said printing hammer to said inoperative position, and a second leaf spring for urging said printing hammer out of engagement with said drive means and toward said first stop whereby said printing hammer engages said first stop in said printing position and slides onthe same and on said leaf spring while being returned toward said position of rest by said first spring.

6. A printing hammer arrangement according to claim 1 wherein said printing hammer has a projection with a slanted camming face; and including a stationary guide engaged by said slanted camming face during movement of said printing hammer in said actuated position toward said printing position so that said guide and said slanted camming face move said printing hammer out of said actuated position whereby said printing hammer is disengaged from said drive means before arriving in said printing position.

7. A printing hammer arrangement according to claim 6 wherein said actuating means include electromagnetic means having a movable selector member; and including a thin resilient coupling member 'between said selector member and said printing hammer and engaged and bent by said selector member when said electromagnetic means is actuated, said bent resilient coupling member engaging said printing hammer in said position of rest and moving the same to said actuated position for engagement by said drive means.

8. A printing hammer arrangement according to claim 1 and including cam means for moving said printing hammer out of engagement with said drive means during movement of said printing hammer toward said printing position.

References Cited by the Examiner UNITED STATES PATENTS 9/1935 Buhler "101-93

Claims

1. PRINTING HAMMER ARRANGEMENT FOR A LINE PRINTER COMPRISING, IN COMBINATION, TYPE CARRIER MEANS MOVABLE FOR PLACING TYPES SUCCESSIVELY IN A PRINTING AREA; A PRINTING HAMMER COOPERATING WITH SAID TYPE CARRIER MEANS; SUPPORTING MEANS INCLUDING A PAIR OF GUIDE MEMBERS LOCATED ON OPPOSITE SIDES OF SAID PRINTING HAMMER FOR SUPPORTING THE SAME FOR FORWARD MOVEMENT BETWEEN AN INOPERATIVE POSITION AND A PRINTING POSITION IN WHICH A PART THEREOF IS LOCATED IN SAID PRINTING AREA, AND ALSO FOR TURNING MOVEMENT IN SAID INOPERATIVE POSITION BETWEEN A POSITION OF REST AND AN ACTUATED POSITION; FIRST AND SECOND STOP MEANS FOR STOPPING SAID TURNING MOVEMENT OF SAID PRINTING HAMMER IN SAID POSITION OF REST AND SAID ACTUATED POSITION, RESPECTIVELY; ACTUATING MEANS FOR TURNING SAID PRINTING HAMMER FROM SAID POSITION OF REST TO SAID ACTUATED POSITION; DRIVE MEANS ENGAGING SAID PRINTING HAMMER IN SAID ACTUATED POSITION FOR MOVING THE SAME FORWARD TO SAID PRINTING POSITION; AND RESTORING MEANS FOR RETURNING SAID PRINTING HAMMER FROM SAID PRINTING POSITION TO SAID POSITION OF REST.