US2117451A - robertson - Google Patents

Description

May 17, 1938. w. H. ROBERTSON' CASH REGISTER Original Filed Jan. 10, 1930 2 Sheets-Sheet duo: (4:

May 17, 1938. H. ROBERTSON CASH REGISTER Original Filed Jan. 10, 1930 2 Sheets-Sheet 2 FIG.

gnwmtoz William H. Robertson Hi8 dfliozmq Patented May 17, 1938 UNITED STATES CASH REGISTER William H. Robertson, Dayton, Ohio, assignor to The National Cash Register Company, Dayton, Ohio, a corporation of Maryland Original application January 10, 1930, Serial No. 419,938. Divided and this application June 21, 1935, Serial No. 27,619. In Canada March 24,

11 Claims.

This, invention relates to printing mechanism for cash registers and like machines, but more particularly to impression hammer controlling mechanism for machines of the type illustrated and described in Letters Patent of the United States No. 1,816,263, issued August 4, 1931, and United States Patent No. 1,929,652 issued October 10, 1933 both to William H. Robertson, and, in application for Letters Patent of the United States, Serial Number 419,938 filed January 10, 1930 by William. H..-Robertson, now Patent No. 2,056,485. This application isa division of the above named application.

One object of this. invention is to provide machines. of the character disclosed in the above patents and application with mechanism to prevent the rebounding of the impression hammers and thereby preventing the possibility of blurring the record material.

Another object is to contrive mechanism to govern the number of impression strokes the printing hammers make during, a single machine operation.

Still another object is to devise mechanism to control the effectiveness of one of, two printing platens carried by one of the impression hammers.

With these and incidental objects in view, the invention includes certain novel features of construction and combinations of parts, the essential elements of which are, set forth in appended claims and a preferred form or embodiment of which is hereinafter described with reference to the drawings which accompany and form a part of this specification.

In said drawings:

Fig. 1 is a side elevation as observed from the right of the machine, depicting the impression mechanism and the operating means therefor.

Fig. 2 is a detail view of the rebound preventing mechanism for the upper impression hammer.

Fig. 3 is a detail view of the rebound preventing mechanism for the lower impression hammer.

Fig. 4 is. a facsimile of a printed ticket or postage label issued by the machine of this invention.

Fig. 5 is a side elevation of the mechanism for controlling the impression strokes of the upper impression hammer,

50 Fig. 6 is a detail view of the operating mechanism associated with the hammer disabling mechanism pictured in Fig. 5.

Fig. '7 is a top plan view of the upper impressio hammer and portrays in particular the mechanism associated with the shiftable platen block carried by said hammer.

Fig. 8 is a facsimile of a fragment of a permanent detail strip used in the machine of this invention. Fig. 8 also represents a fragment of an issuing detail strip which is identical in every way to the permanent detail strip.

GENERAL DESCRIPTION The printing mechanism used in the machine chosen to illustrate one form of the present invention is identical with that disclosed in the parent application and includes two groups. of type carriers simultaneously set by differential mechanism under control of depressed amount keys in adding operations and under control of the totalizer wheels in totalizing operations. One printing hammer is provided to take impressions from one group of type carriers on an issuing detail strip and another impression hammer is provided to take a plurality of impressions at each operation of the machine from the other group of type carriers, one of such impressions being made on an issuing ticket and another on a permanent detail strip.

The lower hammer makes one printing stroke each machine operation to effect a single impression on the issuing detail strip. However, the upper hammer may be controlled at will to make one or two printing strokes. during each opera tion of the machine. When the upper hammer makes two printing strokes, the first impression is made upon an issuing ticket, and after this ticket is ejected from the path of the hammer the impression is duplicated on the permanent detail strip. When the upper hammer is positioned to make only one printing stroke, the feed of the issuing ticket is disabled and the impression is made on the permanent detail strip.

As the issuing ticket is only about half as wide as the permanent detail strip and covers only a part of the type carriers, it is necessary to provide means to prevent a double impres-- sion being made upon the part of the detail strip not covered by the issuing ticket when the upper hammer makes two printing strokes. This is accomplished by meansof a shiftable platen block carried by the upper impression hammer which cooperates with the portion of the permanent detail strip and type carriers not covered by the issuing ticket. Prior to the first impression, the shiftable platen block is moved away from the type carriers to prevent an impression being made on the permanent detail strip at this time. Prior to the second printing stroke of the hammer the movable impression block is shifted back to effective position.

The impression hammers disclosed herein are actuated by strong springs, which arecocked by a camming device and suddenly released. Just before the hammers contact the record material, the action of the strong spring is abruptly terminated; the momentum of the hammers being sufficient to complete the impression stroke. The force of the impact of the resilient platen blocks against the type carriers is sufficient to cause the hammers to rebound more or less violently and this rebound reacts against the spring actuating means sufficiently to make a light second impression stroke, which almost invariably blurs the record material. In the present application, mechanism is disclosed which makes it impossible for the hammers to make a rebounding repeat stroke.

For a complete disclosure of the machine and particularly the printing mechanism to which the instant invention is applied, reference may be had to the parent application cited at the beginning of this specification.

DETAILED DESCRIPTION Type wheels Referring to Fig. 1, groups of type wheels 515 and 516 are rotatably supported on rods 5'11 and 518 projecting from a printer frame (not shown) suitably secured to a right side frame 36 and properly spaced therefrom. A shaft 215 journaled in the main frames of the machine, and a plurality of telescoping tubes 214 supported by said shaft extend from the accumulating section of the machine through the frame 30 and into the printing mechanism. The shaft 215 and the tubes 214 have fast on the outer ends thereof gears 286 meshing with pinions 581, one of which is secured on the side of each of the type wheels 515. The gears 2811 are also connected by intermediate gears 582, to pinions 584 secured to each of the type wheels 516. By this means the differential positioning of the shaft 215 and tubes 214, imparted thereto by the machine differential mechanism, is transmitted to the type wheels 515 and 516 and sets these wheels to print characters corresponding to the depressed amount keys in adding operations or the totalizer wheels in totalizing operations.

A reversible inking ribbon 585 is alternatively unwound from and wound onto spools 586 and 581 supported respectively on studs 588 and 589 projecting from the printer frame (not shown). The inking ribbon 585 is directed by various studs and plates carried by an ink ribbon support plate (not shown) between the type wheels 515 and 516 and their respective impression hammers. Mechanism is provided to feed the ribbon and to reverse the direction of travel of said ribbon. However, such mechanism is not disclosed herein, but reference may be had to the U. S. Patent No. 1,929,652 issued October 10, 1933 to William H. Robertson, for a full disclosure of this mechanism.

Impression hammers The printing mechanism of the instant machine includes a lower impression hammer 612 and an upper impression hammer 613 pivoted respectively on studs 363 and 622 secured in the frame 36 and carrying respectively resilient impression blocks or platens 611) and 611. A spring 616 is tensioned to urge the hammer 612 counterclockwise to normally maintain a stud 611 in a downwardly extending arm 614 of said hammer in contact with a projection 618 of a hammer operating arm 619 fulcrumed on the stud 303 and urged clockwise into contact with a stop stud or abutment 621 by a comparatively strong spring 620. A downwardly extending arm 625 of the hammer 613 carries a stud 624 normally maintained in contact with a projection 626 of a hammer operating lever 621 loose on the stud 622, by a spring 623 tensioned between said lever 621 and said arm 625. A strong spring 628, one end of which is attached to a rearwardly disposed arm of the lever 621 urges said lever counterclockwise to normally maintain a roller 636 on a forwardly extending arm 631 of said lever in contact with the periphery of a hammer operating cam 632 secured on the main drive shaft 216.

The main drive shaft 216 makes a complete counterclockwise revolution each machine operation and during this rotation lobes 633 and 534, on the cam 632, in cooperation with the roller 6311 rocks the lever 621 and the hammer 613 clockwise, flexing the spring 628. The arm 631 carries a stud 635 which in cooperation with a projection 636 of the arm 619 imparts counterclockwise movement to said arm 6 I 9 and the hammer 612 to flex the spring 620 when the lever 621 receives clockwise movement as explained directly above.

During rotation of the shaft 216 the lobes 633 and 634 move beyond the roller 636 and into contact with a nose 631 of the arm 631. When the nose 631 rides off the lobes 633 and 634 the springs 628 and 62D sharply retract the lever 621 and the arm 619 until such movement is arrested by into contact with the type wheels to record the 5:7

transaction.

It is desirable that the impression hammer 612 make only one printing stroke to make a single impression upon an issuing detail strip 112, while the hammer 613 is making two printing strokes. The hammer 612 is prevented from making the first impression stroke by the high portion of a segment 638 secured to the cam 632 in cooperation with an arcuate surface of a projection 639 of the arm 619. During rotation of the main shaft 216 the high portion of the segment 638 passes under the projection 639 before the nose 631 rides off the first lobe 633 of the cam 632. This blocks clockwise imprinting movement of the arm 619 and the hammer 612 under influence of the spring 620 and it is therefore evident that said hammer 612 is thus prevented from making the initial imprinting movement in unison with the hammer 613. Just before the nose 631 rides off the lobe 634 to effect a second impression stroke of the hammer 613, the high surface of the segment 636 moves beyond the projection 639, thus permitting the hammer 612 to move in unison with the hammer 613 during its second printing stroke to make a single impression upon the issuing detail strip 112.

Mechanism to prevent rebound of the printing hammers When the hammers 612 and 613 (Fig. 1) make a printing stroke, sharp contact of their respective platens 6111 and 611 with the type carriers and the resiliency of said platens causes said hammers to rebound sharply. This causes the studs 611 and 624 to contact the projections 618 V and 626 with suiiicient force to slightly rock the arms 619 and 62? against the tension of their respective springs 62!] and 628. The resulting return movement of the arms 619 and 631 is sufficient to cause the hammers 612 and 613 to make a second light impression stroke, commonly referred to as a rebound stroke, which generally results in a blurring or smudging of the first impression made on the record material. In the present machine this undesirable condition has been overcome by means of individual rebound preventers associated with each of the hammers. These rebound preventers positively block any rebounding movement of the impression hammers subsequent to an impression stroke. Both of the rebound preventers operate upon the same principle, but due to difference of structure therein it is deemed advisable to describe each of them in detail.

A flattened pin 645- on a downwardly extending arm 646 of the hammer 6I2 normally lies in a recess formed in the upper edge of a rebound. preventing arm 641 (Figs. 1 and 3) pivoted on a stud 646 extending between the frame 36 and the printer frame (not shown). The pin 645 also lies within a larger recess in a detent slide 649, slidably supported by the stud 648 and a stud 656 in the arm 641, said recess being large enough topermit relative movement of the stud 645 thereto. counterclockwise cocking movement of the hammer 6I2 causes the stud 645 in cooperation with an inclined wall of the recess in. the arm 641 to rock said arm and the slide 649 counterclockwise against the tension of a spring 653. Counterclockwise movement of the slide 649 moves a projection 652 thereon below a flattened stud 651 secured in the frame 30. Immediately thereafter continued counterclockwise movement of the arm 6I2 causes the stud 645 to engage the rearwardly disposed wall of the recess in the slide 649 to shift said slide rear.- wardly to move the projection 652 thereof directly underneath. the stud 65L This. retains the forward wall. of the recess in the arm 641 out of the path of the stud 64,5 upon return printing movement of the hammer 6I2' under influence of the spring 620' and allows said stud to. engage the forward wall of the recess in the slide 649 to shift said slide forwardly to move the projection 652 out of the path of the stud 65I. The spring 653 immediately returns said slide and the arm. 641. upwardly until the top edge of the arm 641 contacts. the stud645. When the printing hammer 612' recoils from its impact with the type carriers, in the manner explained above,. the stud 645 moves off. the top edge of the arm 641 and into the recess therein. permitting said arm and the slide 649 to be returned full. distance upwardly by the spring 653 to. the position here shown. This moves the forward wall of the recess in the slide 641 in the path of the flattened surface of the stud 645 to positively block re-- bounding. movement of the hammer M2.

The rebound preventer for the hammer 6I3 (Figs. 1 and 2) functions similarly to the rebound preventer for the hammer 6I2. However, due to the fact that this rebound preventer varies in structure from the one just described, it is deemed advisable to give a detailed description thereof. When the lobes 633 and 634 of the cam 632 retract the hammer 6I3 clockwise, preparatory to a printing stroke of said hammer, a stud 654 in an extension 655 of said hammer in cooperation with an angular surface on a rebound preventing lever 656, rotatably' supported on a stud 651 secured in the frame 36, rocks said lever clockwise. Clockwise movement of the lever 656 is transmitted to a detent slide 659, slidably mounted by means of slots therein in. cooperation with the stud 651 and a stud 658 in a rearward arm of said lever 656,. by means of said stud 658. Clockwise movement of the lever 656 and the slide 659' flexes a spring 660 and rocks a shoulder 66I= of said slide 6.59 out of the path of or beneath a stud 662 projecting from the frame 30. Continued a clockwise movement of the hammer 6I3 causes the stud 654 to engage the rearward wall of a notch in the forward end of the slide 659 and. shifts said slide rearwardly to move the shoulder or step 661 beneath the stud 662, to restrain return movement counterclockwise of the lever 666 and slide 659 under influence of the spring 666 when the hammer starts its imprinting movement counterclockwise. The stud 662 (Fig. 2) retains the slide 659 and the lever 656- in clockwise positionduring the greater part of the imprinting stroke of the hammer 6I 3 until the stud 654 moves beneath a hook-shaped projection 644 of said lever 656. Near the termination of its counterclockwise movement the stud 654 engages the inner wall of the notch in the slide 659 and shifts said slide forwardly to move the shoulder 66! from beneath the stud 662, thus permitting the spring 660 to return the lever 656 counterclockwise until the projection 644 rests on top of the stud 654 Recoil clockwise of the hammer 6I3 caused by impact of the platen 6 with the type carriers causes the stud 654 to ride off of the lower surface of the projection 644 and the spring 660 immediately returns said lever 656 to normal position to place the projection 644 in the path of the stud 654 to positively block rebounding movement of the hammer 6I3.

Control of ticket printing and issuing mechanism by transaction keys Depressing the transaction key 44 (Fig. 5) controls the printing mechanism to issue a permit ticket 691- (Figs. 1 and 4). Depressing any one of the three keys 45, 46 or 41 operatesmechanism that prevents the permit ticket printing hammer 6I3 from making its first impression stroke and renders ineffective the permit ticket feeding mechanism.

The keys 45, 46 and 41 eachcarry a stud I03 which cooperate respectively with the angular camming surfaces of three tooth-shaped projections of a sector I65 formed on the outer end of an arm I66 fulcrumed on a differential supporting shaft I49 journaled in the main frames of the machine. Depressing any one of the keys 46, 46 or 41 by means of the stud I63 in cooper ation with the angular camming surface rocks the sector I65 and the arm I66 clockwise which movement by means of a link I61, connected between the sector I65 and. the upper end of an arm I68, is transmitted to said arm I68. The arm I68 is secured to a short shaft I69 journaled in the right frame 30 and a bracket not shown. Consequently said shaft moves in unison with the arm I 68. Clockwise movement of the arm I68 shifts a pitman 663 rearwardly, the forwardend of said pitman being pivoted at 615 to said arm I66 and the rearward end of said pitman being slotted to embrace a stationary stud 664 projecting inwardly from the frame 30. Rearward movement of the pitman 663 causes a downward projection 665 thereof in cooperation with a stud 666 inan arm 661 loose on a rod 566 supported by the main frame, to shift said arm 661 clockwise.

The arm 661 is flexibly connected by a spring 668 to a hammer arresting lever 669 also. loose on the rod 566. The spring 668 normally maintains a raised surface of the arm 661 in contact with a stud 616 secured in the lever 669. The lever 669 carries a stud 610 which extends within a slot 61I in the lower end on a link 612 (see also Fig. 1) the upper end of said link being pivotally connected to a crank 613 secured on a shaft 439 journaled in the right and left indicator end frames, the right one (35) of which is here shown in dot and dash lines.

counterclockwise rotation of a shaft 213 (Fig. 6), as explained fully in the parent application, rotates companion plate cams 421 and 426 in unison therewith.

The peripheries of the cams 421 and 428, in cooperation with their respective rollers 429 and 436 on the Y-shaped'arms of a cam lever 43I fulcrumed on a rod 432, rocks said lever first counterclockwise and then back to normal position, as here shown.

Oscillating movement of the lever 43I first lowers and then raises a pitman 433, the lower end of which is pivoted to said lever 43I, and the upper end of said pitman being guided by a slot therein in cooperation with a rod 435 extending between the indicator frames. Oscillating movement of the pitman 433 by means of a stud 436 in the upper end thereof, in cooperation with a horizontal slot in a crank 436 secured on the shaft 439 rocks said crank and said shaft first counterclockwise and then back to normal position. Initial movement counterclockwise of the shaft 439 (Figs. 1 and 5) and the crank 613 moves the link 612 downwardly thus allowing the spring 668, which has been tensioned by clockwise movement of the arm 661 under influence of the pitman 663, to move the lever 669 in unison with the link 612. Clockwise movement of the lever 669 moves a surface 614 on the broad end thereof opposite the stud 654 in the hammer 6I3 to block clockwise retracting or cocking movement of said hammer, thereby preventing said hammer from being influenced by the first lobe 633 of the cam 632 in cooperation with the lever 621 and the spring 628.

Before the second lobe 634 of the cam 632 imparts cocking movement to the lever 621 the companion cams 421 and 428 in cooperation with the lever 43I shifts the pitman 433 upwardly to return the shaft 439, the crank 613 (Fig. 1) and the link 612 to normal position as here shown. Return movement upwardly oi the link 612 (Fig. 5) returns the disabling lever 669 counterclockwise to normal position to remove the surface 614 thereof from the path of the stud 654. The hammer 6I3 then makes its single printing stroke under influence of the lobe 634 of the cam 632 to make an impression upon the permanent detail strip 199 (Fig. 1) which is unwound from a supply roll, (not shown) threaded around various guide studs and two rollers 805 turnably supported by plates 896 (see also Fig. 7) secured to the hammer 6I3 and finally wound upon a receiving roll (not shown). For a complete description of the permanent detail strip feeding mechanism reference may be had to the parent Patent No. 2,056,485.

The transaction keys 45, 46 and 41 (Fig. 5) are stay-down keys and are therefore not influenced by the automatic key releasing mechanism. It is therefore evident that as long as one of these keys is depressed the pitman 663 retains the arms 661 in clockwise position to tension the spring 668 and consequently the lever 669 will operate each machine operation to block the first imprinting movement of the hammer 6| 3. Depressing the transaction key 44, in a manner explained in the parent application, releases any depressed transaction key 45, 46 or 41, thus permitting a spring I1I (Fig. 5) in cooperation with a crank I12 secured to the shaft I69 to return said shaft, the lever I68, and the pitman 663 and the sector I65 to normal position as here shown. The tensioning arm 661 returns in unison with the pitman 663 to relieve the tension of the spring 668, thus preventing clockwise movement of the lever 669 when the link 612 is lowered in the manner explained above. When the lever 669 remains in its ineffective position, the slot 61I in the link 612 prevents the up-and-down movement of said link from imparting movement to the stud 619 and lever 669. It is therefore to be understood that when the machine is operated with the transaction key 44 depressed, the hammer 6I3 is free to make two impression strokes, the first of which causes a record of the transaction to be imprinted upon the permit ticket 691 (Figs. 1 and 4) and the second upon the permanent detail record strip 199 (Figs. 1 and 8).

Shiftable platen for the permit ticket printing hammer By referring to Figs. 1 and 7 it will be seen that the permanent detail strip 199 is guided by the rollers 965 around the head of the hammer 6I3 and maintained in close relationship to the platen block 6| I. It will likewise be observed that the issuing ticket 691 is fed upwardly between the inking ribbon 585 and the permanent detail strip 199. Therefore when the transaction key 44 (Fig. 5) is depressed, the web of the issuing ticket 691 is fed upwardly between the ribbon 585 and the permanent detail strip 199. Consequently the first impression will be made on the issuing ticket 691. Immediately after being imprinted the ticket 691 is ejected from the machine, thus permitting the second impression to be made on the permanent detail strip 199. When one of the transaction keys 45, 46 or 41 is depressed, the feed for the issuing ticket 691 is disabled; consequently the web of said ticket is not fed upwardly between the ribbon and the permanent detail strip. In such a case there is no need for two impression strokes of the hammer M3 and therefore the first impression stroke of the hammer is disabled in the manner explained above and the second impression stroke causes the transaction to be recorded upon the permanent detail strip 199.

By referring to Fig. 7 it will be noted that the ticket 691 covers only part of the type wheels 516 and is only about half as wide as the permanent detail strip 199. Therefore to prevent the first stroke of the hammer from making an imprint upon the portion of the permanent record strip not covered by the issuing ticket 691 a shiftable platen is provided which is moved to an ineffective position during the first printing stroke of said hammer. The shiftable platen and associated mechanism will now be described.

Directing attention to Figs. 1, 5 and '1, the impression hammer 6I3 has at its upper end a laterally extending table 685 with an upwardly extending rib 684 extending the full width of the type wheels 516. Substantially half of the rib 684 (Fig. 7) is channeled to receive the impression block 6 while the other half of said rib is cut away to provide room for a platen supporting bar 68I channeled to receive a platen block 689 adapted to make imprints upon the portion of the permanent detail strip 199 not '68! secured to the table 685.

centric shaft 66L covered by the issuing ticket 691. The platen bar 68! is supported by the forward ends of plungers 682 and 683 which extend.- through holes in the rib 684 and are further supported by holes in ears 686 projecting from a bracket Compression springs 688 wound around the plungers 682 and 683 are confined between the rail 684 and collars 689 one of which is secured to each of the plungers 682 and 583. I The springs 688 urge the plungers 682 and 683 rearwardly as viewed in Fig. 1 and downwardly as viewed in Fig. '7, to normally maintain rollers, turnably mounted in slots in the ends of said plungers, in contact with the peripheries of symmetrical cams 696.

The cams 690 are secured on a shaft 69I turnably and shiftably supported in substantially horizontal slots in a pair of upturned ears 692 of the bracket 681. Loose on the shaft 69] are two eccentrics 105, which in cooperation with studs 168 in extensions of the ears 692 provide a means of adjusting the shaft 69! and the cam 690 in relation to the plungers 682 and 683; thus providing a means of adjusting the platen bar Bill and the platen 680 relatively to the type wheels 516 to control the impression. The eccentrics 105 have knurled rims 106 which provide an easy means of adjusting said eccentrics, and which in cooperation with retaining clips 10! (Fig. 1) secured to the table 685 provide a means of retaining the eccentrics in adjusted position.

Secured on the righthand end of the shaf 69! (Figs. 1 and'l) is a crank 695 connected by a link 694 to an arm 693 secured on a shaft 426 journaled in the indicator frame. Also secured on the shaft 426 (Fig. 6) is a crank 431 slotted to receive the stud 436 in the pitman 433.

As explained hereinbefore, depressing the transaction key 44 (Fig. 5) conditions the printing mechanism to make two impressions, one on the issuing ticket 691 (Fig. 7) and the other on the permanent detail strip 199. The first'impression is made on the ticket 691 after which said ticket is severed from its web and ejected from the machine, and the second impression is made on the permanent detail strip 199. Prior tothe first impression stroke of the hammer 6l3 the cams 421 and 428 (Fig. 6) in cooperation with the lever 43l shift the pitman 433 downwardly to rock the crank 43'! and the shaft 426 a slight distance clockwise. The arm 693 (Fig. 1) and the link 664 transmits clockwise movement of the shaft 426 to the arm 695 and the ec- Clockwise movement of the shaft 69l moves the high portions of the cams 696 away from the plungers 682 and 683 whereupon the springs 688 (see also Fig. 7) shift said plungers and the platen bar 68I away from the type carriers so that the first impression will not be made on the portion of the detail strip 199 not covered by the issuing ticket 691. Immediately after the first impression is completed and before the second impression, the cams 421 and 428 and connected mechanism return the shafts 426 and Bill counterclockwise to normal position as here shown, whereupon the cams 690 restore the platen bar Bill to printing position so that the second impression will be made upon the full width of the permanent record strip 199.

The mechanism just described for shifting the platen bar 68l (Fig. 7) out of and into printing position functions every machine operation, and while it is unnecessary for this mechanism to operate when the printing mechanism has been conditioned by depression of one of the transaction keys 45, 46 or 41 (Fig. 5) for a single impression, still its operation at this time does no harm whatever.

While the form of mechanism herein shown and described is admirably adapted to fulfill the objects primarily stated, it is to be understood that it is not intended to confine the invention to the one formor embodiment herein disclosed, for it is susceptible of embodiment in various forms, all coming within the scope of the claims which follow.

What is claimed is:

1. In a machine of the class described; the combination with a manipulative device; a printing hammer; and means to cause the printing hammer to deliver a plurality of impression blows at each operation of the machine; of normally idle means to block the printing hammer against operation; a tension member to shift the blocking means to effective-position; means controlled by the manipulative device to actuate the tension member; and means to release the blocking means for movement into blocking position and then restore said blocking means into idle position.

2. In a machine of the class described, the combination with a printing hammer; a manipulative device; and means to cause the hammer to deliver a plurality of impression blows at each operation of the machine; of normally idle preventing means to render the printing hammer ineffective; means controlled by the manipulative device to control the operation of the preventing means; and means timed with relation to the hammer-operating means, to release the preventing means for operation prior to an operation of the hammer and to restore the preventing means to ineffective position after the operation of the hammer.

3. In a machine of the class described; the combination with a manipulative device; a printing hammer; and means to cause the hammer to deliver a plurality of impression blows at each operation of the machine; of a normally ineffec tive means to disable the hammer; a tension arm; a spring connecting the disabling means and the tension arm; means operated by the manipulative device to shift the tension arm to place additional tension on the spring; and means normally in position to restrain said disabling means against operation and operable during a machine operation to release said disabling means at a predetermined time.

4. In a machine of the class described; the combination with a manipulative device; a printing hammer; and means to cause the hammer to deliver a plurality of impression blows at each operation of the machine; of a normally ineifective means to disable the hammer; means controlled by the manipulative device to operate the disabling means; and restraining means to release the disabling means for operation before the time of the first impression blow of the hammer and to restore the disabling means to ineffective position before the time of the second operation of the hammer.

5. In a machine of the class described; the combination with a manipulative device; a printing hammer; and means operable at each operation of the machine to cause the printing hammer to deliver a plurality of impression blows; of a normally idle means to disable the hammer; a tension arm, a spring connecting the tension arm and the disabling means; a pitman; means controlled by the manipulative device to actuate the pitman and rock the tension arm; a link coacting with the disabling means to restrain the disabling means against operation; and means to operate the link to release the disabling means to the action of the spring before the time of occurrence of one of the impression blows and to restore the disabling means to idle position thereafter.

6. In a machine of the class described; the

combination with type elements; a printing hammer; and a platen; of plungers carried by the hammer to adjustably support the platen; resilient means tending to retract the adjustable platen; a shaft; restraining members on the shaft coacting with the plungers tonormally maintain the adjustable platen in printing position; and means to rock the shaft and the restraining members to release the plungers to the action of the resilient means, whereby the platen is withdrawn from printing position.

7 In a machine of the class described, the combination with a printing hammer; and means to cause the hammer to deliver a printing blow; of means to prevent rebound of the hammer against the printing face, including a hammer-arresting member normally in arresting position; a latching member associated therewith for relative movement in one line only to latch the member out of arresting position; and means on the printing hammer cooperable with the hammerarresting member and the latch, whereby the member is moved out of and into arresting position and the latch is moved into and out of latching position.

8. In a machine of the class described, the combination with a printing hammer and means to actuate the hammer, of means to block the hammer, movable from a normally ineffective position into an effective position; normally ineffective means to move the blocking means to said effective position; means to render the moving means effective; and means cooperating with the blocking means to release said blocking means to move to effective position under the influence of the moving means, and to thereafter return the blocking means to ineffective position.

9. In a machine of the class described, the combination with a printing hammer and means to actuate the hammer, of means to block the hammer against actuation, movable from a normally ineifective position into an effective position; a member to normally retain the blocking means in ineffective position; a normally ineffective means rendered. effective upon withdrawal of the member to move the blocking means to effective position; and means to operate the member to release the blocking means to move to e1- fective position under influence of the moving means, said operating means also adapted to return the blocking means to ineffective position.

10. In a machine of the class described, the

combination with a printing hammer and means to disengage the member from the retaining means; and means to move the element into effective position to obstruct rebounding printing movement of the hammer when it is released by the hammer.

11. In a machine of the class described, in combination with a printing hammer, means to retract the hammer, and a spring to operate the hammer to effect a printing operation, of a pivoted arm provided with a shoulder normally in the path of the hammer to prevent rebound of 1 the hammer after a printing operation; a slide connected with the arm to pivot with the arm and to move relatively thereto; a stop; a cam on the arm coacting with the hammer as the hammer is retracted towithdraw the shoulder from the path of the hammer and to move the slide relatively to the stop; a shoulder on the slide coacting with the hammer whereby the slide is moved by the hammer into a position to engage the stop wherein the arm is held out of the path of the hammer as the hammer makes its printing operation; an abutment on the slide in the path of the hammer whereby the hammer moves the slide to disengage the slide from the stop as the hammer makes its printing operation; and a restoring spring to restore the arm and slide into their initial positions when the slide is disengaged from the stop to position the shoulder on the arm into the path of the hammer to arrest the hammer as it rebounds from its operating spring after a printing operation. 1

WILLIAM H. ROBERTSON.

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