US3139820A - Print hammer mechanism - Google Patents

Description

July 7, 1964 M. J. KITTLER PRINT HAMMER MECHANISM Filed Oct. 16, 1961 ATTORNEY United States Patent M 3,139,820 PRINT HAMMER MECHANISM Milton J. Kittler, Bloomfield Hills, Mich., assignor to Holley Carburetor Company, Warren, Mich., a corporation of Michigan Filed Oct. 16, 1961, Ser. No. 145,414 2 Claims. (Cl. 101-93) This invention relates to printers, and more particularly to a print hammer mechanism that could be employed with the type of printer disclosed in US. application Serial No. 138,157, entitled High Speed Printer, and filed on September 14, 1961, in the names of Arvin D. McGregor and James M. Irvine, Jr.

The structure disclosed in the above referenced application included a print drum that had rows of characters to be printed formed thereon, a row of print hammers positioned adjacent the drum and having one hammer for each character in the row of characters on the drum, a continuously rotating multiple lobe cam, and an inter poser system for each print hammer actuated by appropriate print signals in a manner to cause the print cam to simultaneously drive all addressed hammers into the drum. This structure was referred to as a mechanical amplifier system wherein low power electrical signals released the high energy of a mechanical hammer impacting system.

This invention relates to a generally similar type of hammer system which could be made to operate in the printer referred to above. Accordingly, an object of the invention is to provide a mechanical amplifier type print hammer mechanism.

Another object of the invention is to provide a mechanical amplifier type print hammer mechanism employing an interposer system wherein the hammer impacting means operates continuously but the hammers are actually impacted for printing only when the interposer system is in the print position.

Another object of the invention is to provide a print hammer mechanism such as that referred to above, where in the print hammer itself operates both in response to impact and with the assistance of certain spring means.

A more specific object of the invention is to provide a print hammer mechanism wherein the print hammer is of a composite construction.

These and other objects and advantages of the invention will become apparent upon reference to the following specification and the attached drawings wherein:

FIGURE 1 is a schematic illustration of a print hammer mechanism embodying the invention, with the single print hammer and its associated mechanism being in the non-print position;

FIGURE 2 is a fragmentary portion of FIGURE 1 illustrating the initial steps in the print cycle;

FIGURE 3 is a fragmentary portion of FIGURE 1 illustrating the printing hammer mechanism in the final steps of the print cycle.

Referring to the drawings in greater detail, a printer embodying the invention may include a main or other frame member 19 having acylindrical print drum 12 mounted thereon so as to be either continuously or intermittently rotated in either direction. The print drum may have axially extending rows ofcharacters 14 to be printed formed thereon and adapted by the rotation of the drum to be presented at theprinting station 16 for printing on therecord strip 18, with aprint ribbon 20 being positioned between the drum and the record strip.

A printer embodying the invention may also have an elongated continuously rotatingcam 22 mounted on theframe member 10, the cam member having one ormore lobes 24.

As already stated above, a printer embodying the m- 3,139,820 Patented July 7., 1964 Vention would be provided with oneprint hammer assembly 26 for each character in a row of characters on the drum. If there were characters in a row on the drum, for example, there would be 120 hammers 128 positioned side by side and spaced according to the spacing of thecharacters 14 on the drum.

One feature of the invention is that theprint hammer 28 is a composite structure comprised of two separate members, afirst member 30 positioned closer to the cam and asecond member 32 positioned closer to theprint drum 12, the latter member having a relatively hardcharacter impacting surface 34 formed thereon or secured thereto. Themembers 30 and 32 are connected by a lostmotion slot 36 andpin 38 arrangement; in the structure shown, theslot 36 is formed in themember 30 and thepin 38 received in the slot extends laterally from themember 32. Thecomposite print hammer 28 is guided for reciprocating movement along the line AB extending between the axes of the cam and the print drum, respectively, by an suitable means such asrods 40 or other suitable guide members extending along the entire bank ofhammers 28.

Aspring 42 of any suitable design is positioned in aslot 44 formed in theprint hammer member 32 so that thearms 46 and 48 of the spring normally urge the members 3t) and 32 apart to the position shown .in FIGURE 1.Spring 50, which may be anchored to theprinter frame 10, normally urges thecomposite print hammer 28 to ward thecam 22 against thestop 52.

It is apparent, since each individual print hammer is made up of two separate members, that means such as spacer plates could be employed to maintain the individual print hammers and their associated springs apart and in assembled relation, as in the case of the construction disclosed by the above referenced application.

Acam follower 54, which is mounted on theleaf spring 56 having the other end thereof secured by means of ascrew 58 to the printer frame It), is provided for each composite print hammer. The free position of the cam follower may be adjusted by means of a screw 69, one possible adjustment being such that thefollower 54 barely engages the circular edge of thecam 22.

The mechanism associated with each individual print hammer also includes asolenoid 62 secured in any manner to theprinter frame 10 and having an axially movable core with a suitable rod orpin 64 extending toward thespace 66 between thecam follower 54 and themember 30 of thecomposite hammer 28. The rod has aball 68 or other enlargement formed in the free end thereof, the width of which may be almost the width of thespace 66 between thecam follower 54 and themember 30 of the composite hammer when they are in the position shown in FIGURE 1. This constitutes an interposer system, and theball 68 is maintained out of thespace 66, as shown in FIGURE 1, against the force of thespring 70 positioned between theframe 10 and thespring seat 72 secured to therod 64 when thesolenoid 62 is energized.

It is thus seen from FIGURE 1, which shows onehammer mechanism 26 in the non-print position, that no printing can occur, even though theprint drum 12 and thecam 22 may be continuously rotating. In other words, even though the rise orlobe 24 on thecam 22 moves to the dotted line position of FIGURE 1 so that thecam follower 54 is moved to its dotted line position, thecam follower 54 will never engage theprint hammer 28 and no printing can occur.

In the printer of the previously referenced application, the interposer system was maintained in the non-print position by a continuously energized holding coil until a print signal was received to energize a pulse coil which cancelled out the magnetic force of the holding coil and 7 3 permitted a spring to move the interposer system to the print position. Likewise, in this construction, thesolenoid 62 is continuously energized until a print signal is received to ie-energize the solenoid. When this occurs,

thespring 70 causes theball 68 or other member formed on the end of therod 64 attached to the solenoid core to be moved into thespace 66 between the cam follower and themember 30 of the composite hammer. This is shown in FIGURE 2, which illustrates the initial positions of the parts of theprint hammer mechanism 26 during a single print cycle.

It will be seen in FIGURE 2 that therise 24 on the cam causes thecam follower 54 to strike theball 68 which has been previously positioned in thespace 66. Depending upon the resiliency and other characteristics of therod 64 and other hammer parts, the spacing of these parts and other design details, the striking of theball 68 will either push or impact themember 30 of thecomposite hammer 28 to the dotted line position of FIGURE 2 so that the pin 33 engages the end of theslot 36 closest to thecam 22, thespring 50 is deflected to its dotted line position and thespring 42 normally holding apart the two members of thecomposite print hammer 28 is compressed to its dotted line position. At this time, themember 32 of the composite print hammer closest to theprint drum 12 has not yet moved to impact thecharacter 14 on the drum.

The final steps of the print cycle are shown by FIGURE 3, wherein therise 24 on thecam 22 has already passed thecam follower 54 so that the latter has returned to its non-print position against theadjustment screw 60. Theinterposer ball 68 on the rod of the solenoid has been again removed from thespace 66 between the cam follower and themember 30 of the composite print hammer due to re-energization of the solenoid. .Themember 30 of the composite print hammer has not moved from its FIGURE 2 position but thespring 42 normally holding the two parts of the print hammer apart has been re-extended to drive themember 32 of the print hammer into acharacter 14 on theprint drum 12.

The final step of a single print cycle would be for thesprings 42 and 50 to return the composite print hammer to the non-print position shown in FIGURE 1, and no further printing would occur until the cycle described above is repeated, the cycle being initiated by a signal to print resulting in de-energization of the solenoid.

In the construction shown and described, theprint drum 12 is an elongatedcylinder having rows 14 of identical characters, and theprint cam 22 is an elongated cam at least as long as a row of characters formed on the drum. The printer frame would also be an elongated member extending subsequently along the entire length of the drum. There would be one complete hammermechanism 26the solenoid 62 andball 68, thecam follower 54 and itsadjustment screw 60, and a composite hammer including themembers 30 and 32 and thesprings 42 and 50-for each character in a row of characters on the drum.

Whether the hammer actuation is due to thecam 22 actually driving thehammer 28 against thedrum 12, a free projectile type of action due to thecam 22 impactinghammer 28 or any combination of these actions together with the forces of thesprings 42 and 50, would of course depend upon the details of construction of the parts involved. The main feature of the invention is that a low power print signal causing thesolenoid 62 to be de-energized releases higher energy mechanical forces which directly cause the printing. This low electrical power design reduces the cost of a printer and results in many other advantages, such as providing a printer with low radiation noise.

While but one embodiment of the invention has been disclosed, it is apparent that modifications may be made within the scope of the appended claims.

What I claim as my invention is:

1. In a printer having a frame member, a rotating drum having characters formed thereon and a rotating cam, a print hammer mechanism adapted for actuation on a line between the axes of said cam and said drum, said hammer mechanism comprising a spring-mounted cam follower, a print hammer assembly spaced from said follower, a fixed stop intermediate said follower and said print hammer assembly, and an interposer device adapted to be at times positioned between said cam follower and said print hammer assembly, said print hammer assembly being guided for movement along said line of action and including first and second members connected by lost motion means, first spring means for urging said hammer assembly toward said cam and against said stop, and second spring means for urging said first and second members apart so as to take up said lost motion.

2. In a printer, a combination of a rotatable member having characters to be printed formed thereon, a frame member in which said character bearing member is mounted, an elongated cam member mounted on said frame, said cam member being spaced from and parallel to said character bearing member and being at least as long as a row of characters, and a row of print hammer mechanisms between said cam and said character bearing member, there being one print hammer mechanism for each character in a row of characters, each of said print hammer mechanisms comprising a cam follower, a print hammer and an interposer member adapted to be positioned between said cam follower and said print hammer by a signal responsive means when it is desired to print, the line of action of said print hammers being on the line between the centers of said cam and said character bearing member, each of said print hammers being of a composite construction including a first element for actually striking said character bearing element and a second element secured to said first element through lost motion means and adapted to be struck by said cam follower through said interposer member, first spring means for urging said first and second hammer elements to an extended position, and second spring means for urging said second hammer element toward said cam and against a stop, said signal responsive means moving said interposer member upon an appropriate signal from between said cam follower and said print hammer against resilient means urging said interposer member in the opposite direction.

References Cited in the file of this patent UNITED STATES PATENTS

Claims (1)

1. IN A PRINTER HAVING A FRAME MEMBER, A ROTATING DRUM HAVING CHARACTERS FORMED THEREON AND A ROTATING CAM, A PRINT HAMMER MECHANISM ADAPTED FOR ACTUATION ON A LINE BETWEEN THE AXES OF SAID CAM AND SAID DRUM, SAID HAMMER MECHANISM COMPRISING A SPRING-MOUNTED CAM FOLLOWER, A PRINT HAMMER ASSEMBLY SPACED FROM SAID FOLLOWER, A FIXED STOP INTERMEDIATE SAID FOLLOWER AND SAID PRINT HAMMER ASSEMBLY, AND AN INTERPOSER DEVICE ADAPTED TO BE AT TIMES POSITIONED BETWEEN SAID CAM FOLLOWER AND SAID PRINT HAMMER ASSEMBLY, SAID PRINT HAMMER ASSEMBLY BEING GUIDED FOR MOVEMENT ALONG SAID LINE OF ACTION AND INCLUDING FIRST AND SECOND MEMBERS CONNECTED BY LOST MOTION MEANS, FIRST SPRING MEANS FOR URGING SAID HAMMER ASSEMBLY TOWARD SAID CAM AND AGAINST SAID STOP, AND SECOND SPRING MEANS FOR URGING SAID FIRST AND SECOND MEMBERS APART SO AS TO TAKE UP SAID LOST MOTION.

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