US2547895A - Case shift mechanism for typewriting machines - Google Patents

Description

April 3, 11951 J. c. VELTMAN ETAL 2,5425

CASE SHIFT MECHANISM FOR TYPEWRITING MACHINES 5 Sheets-Sheet 1 Fil ed Aug. 27, 1945 on N r s R w n EL r m H V v M u M Jw April 3, 1951 J. c. VELTMAN ETAL 2,547,895

CASE SHIFT MECHANISM FOR TYPEWRITING MACHINES Filed Aug. 27, 1945 3 Sheets-Sheet 2 April 3, 1951 J. c. VELTMAN ETAL CASE SHIFT MECHANISM FOR TYPEWRITING MACHINES 3 Sheets-Sheet 3 Filed Aug. 27, 1945 ATTORNEYS.

patented Apr. 3, 1951 CASE SHIFT MECHANISM FOR TYPEWRITING MACHINES John C. Vcltman and William '0. Michelson, St. Louis County, Mo., assignors to The Emerson Electric Mfg. 00., St. Louis, Mo., a, corporation of Missouri Application August 27, 1945, Serial No. 612,772

10 Claims. (01. 197-73) assembly which are relatively and simultaneously shiitable, whereby the upper and lower case type are selectively positioned to strike the platen on the printing line.

A further object is to construct a machine of this type in such a manner as to provide a balanced shifting device, whereby positioning the segment and type bar assembly, and the platen carriage for double case printing may be eifected with a minimum of movement and a minimum of application of force, whereby wear upon and distortion of parts is substantially avoided.

More specifically an object is to cooperatively support and connect the platen carriage, and segment and type bar assembly in a weight balanced relation, in order that applied force in accomplishing the shifting operation is substantially reduced, resulting in an extremely light shift key action.

Another more specific object is to reduce the movement necessary in effecting relative shift of the platen carriage, and segment and type bar assembly, which results in reducing the inertia of the moving parts, thereby reducing impact on the parts on termination of movement, and

thereby minimizing the noise of operation and wear on the parts as a result of impact at the end of the shift movement.

Another object of the invention is to embody in a typewriting machine having the foregoing characteristics an eliicient shift mechanism for the platen carriage, and segment and type bar assembly, which operates the shift with facility and holds the same in proper adjustment for upper and lower case printing, said shift mechanism having lock devices, which are particularly adapted for such purpose.

Another object of the invention is the provision of a type bar operating means that is particularly adapted for quiet and efiicient operation, particularly in combination with the character of shift mechanism above specified. Additional advantages of the invention will appear from the following detailed description of the invention taken in connection with the accompanying drawings, in which:

Fig. 1 is a skeletonized isometric view of such parts of a typewriting machine as are essential to illustrate the embodiment of the invention, particularly with respect to the type action and relative platen carriage, and segment and type bar assembly shift. In this view the parts are shown in initial position;

Fig. 2 is a similar isometric view further skeletonized to further illustrate essential parts in printing position;

Fig. 3 is a view of certain essential parts of the shift mechanism for shifting the platen carriage, and segment and type bar assembly, and also the upper and lower case locks;

Fig. 4 is a view similar to Fig. 3, in which the parts shown therein are in association with cooperating parts of the printing mechanism;

Fig. 5 illustrates essential parts of the printing mechanism, particularly the key action; and

Fig. 6 is a detail of the stop associated with the universal bar.

As illustrated in the drawings, the machine embodying the invention is shown as including a skeleton frame to be mounted in a conventional manner in a main frame (not shown) The skeleton frame comprises right and left side frame members i and 2, with provision in the form of spaced openings 3 for mounting and attaching said skeleton frame in the mainframe of the machine.

The segment and type bar assembly, and the platen carriage assembly are each pivotally mounted between said frame members I and 2, the former by pivot mountings at ll, adjacent to the front of the machine, and the latter by pivot mountings at 5 adjacent to the rear of the machine.

The general structure of the segment and type bar assembly is best shown in Fig. 2, from which it will appear that, as illustrated, it comprises a 7 segment 6 supported on a transverse plate I,

which extends laterally to each side of the machine. The extremities of the plate 1 are bent to form right angle forwardly extending sections 8, each of which is removably connected with a forwardly extending arm 9, which arm pivots on the respective frame members i and 2 on the pivot member 4.

The lower rail assembly of the platen carriage comprises bracket members Iii, which are cross connected by a tube I A convenient means of securing the extremities of said tube H to the brackets It comprises, as

illustrated, plugs l2 inserted through openings in the respective brackets it, said plugs being inserted into the openings in the opposite ends of the tube I l, and then forming a rigid joint by brazing or welding these parts together. The plugs 12 may be drilled and countersunk to form bearings for pivot screws l3, which are locked by nuts M in the side members I and 2 of the frame, and which screws, therefore, constitute the pivot mountings for said tube I I, which, in turn, serve as the rocking or pivot supports 5 for the platen carriage assembly.

A lower rail extends transversely of the machine. This rail constitutes the support for the platen carriage, it being understood that said carriage is shiftable transversely thereon in the usual manner This lower rail rests upon and is secured to brackets I6 positioned adjacent to each end of said rail. The brackets I6, in turn, are releasably and adjustably secured to the top wall of the respective brackets ID, preferably by screws ll that pass through elongated slots IS in angular extensions IQ of the brackets I6, which screws thread into openings in said top wall of each of the brackets H), as best illustrated in Fig. 2. Since, therefore, the lower rail assembly and the shiftable platen carriage carried thereby are rigid with said brackets H), which, in turn, are pivotally mounted on the pivot screws [3 rigid with the frame, the entire platen carriage support is assembled for rocking movement in respect to the frame of the machine. As will be later explained, the rocking movement of the platen carriage assembly from its normal position of rest is in an arcuate direction opposite from the movement of the segment and type bar assembly in shifting to and from the, upper and lower case printing positions.

The platen carriage assembly, and the segment and type bar assembly are pivotally interconnected at each side by rocking arms 29. The arms 2!! are connected with the respective brackets I 0, at their rear extremities, by screw and slot connections 2| and, at their front extremities, are connected by a screw and slot connection 22 with the plates. 9, which constitute the pivoted arms by which the segment and type bar assembly is supported. The arms 28 constitute rocking arms or levers, having a pivot connection intermediate their extremities with the respective side members I and 2 of the frame. A pivot screw 23 passing through each frame member and through each of said arms serves to permit the relative rocking movement of said arms in respect of the frame, and thereby a rocking counterbalanced connection between the segment and type bar assembly, and the platen carriage assembly.

In order to provide for proper alignment and adjustment between the right and left hand rocking connection between these two assemblies to compensate for any misalignment or distortion in either of them, it is preferable to form one of said arms in two sections, as illustrated, and to join said sections by a dowel, slot and screw connection 24 arranged so that a slight angular adjustment between the two sections of the arm may be made.

The segment and type bar assembly is normally held in raised position by a pair of springs 25, the upper ends of which are adjustably supported in a stationary part of the machine (not shown), and the lower ends are connected, re-

spectively, with the rear section of the plates or arms 9 of the segment and type bar assembly frame. These springs serve to resiliently hold said plates in such angular position that the forward ends of the rocker arms are raised, thereby tilting the platen carriage assembly forwardly and downwardly, and the segment and 4 type bar assembly backwardly and upwardly (Fig. 1).

In order to limit the extent of the relative up and down movements of the segment and type bar assembly, and the platen carriage assembly,

shift motion stops are provided which, as illustrated, include a pair of parallel spaced arms 26 secured to the segment plate 7 adjacent to each end thereof, which cooperate with arms 21, one of which is attached adjacent to each end of the carriage frame in a position to extend through openings in the plate 1 and between said arms 26. The arms 26 are formed of material which may be slightly flexed so that said arms may be adjusted by bending to adjust the limit of the shift movement either up or down, whereby the relative movement of the segment and type bar assembly, and of the platen carriage assembly will be brought to rest for proper alignment of the printing line of the platen for either upper or lower case printing.

A series of type bars 28 are pivotally mounted in and supported by the segment 6 in conventional arrangement. The type bars take the form of bell crank levers and are preferably pivotally supported on a wire 29 seated in a slot formed in the periphery of the segment 6.

It will be understood that the number of type bars 28 preferably includes the usual number from forty-two to forty-six, in order to provide for the usual complement of printing characters arranged on the face of the type 30 in upper and lower case arrangement.

The segment 6 is provided with the usual spacing walls 3| forming slots that guide the individual type bars.

In the drawings, only sufficient of the type bars have been illustrated to disclose the arrangement thereof in relation to the structure of the present invention.

The key levers 32 for operating the type bars are supported in a key lever bracket 33, which is supported transversely of the machine, and is rigidly connected at its extremities to the inner faces, respectively, of the plates 9 constituting the side members of the frame of the segment and type bar assembly, whereby the type bars and their operating means move as a unit in shifting movements.

A series of spaced key lever guides 34 in the form of bifurcated lugs form slots in which the inner ends of the key levers 32 are seated. The inner ends of the key levers 32 are pivoted on a rod 35 passing through openings in the levers and seated between the aligned arms of the members 34. A comb 36 is positioned forwardly of the bracket 33, which comb is also supported at its extremities by the plates or arms 9. This comb 33 has a series of vertical slots extending from its bottom edge through which the key levers 32 extend and are guided thereby.

A series of intermediate bell crank levers 31 are carried by and pivoted upon a rod 33 supported in the lower section of the key lever bracket 33. A series of spaced slots 39 extend upwardly from the bottom of said bracket and constitute guides in which said levers 3'! rock.

Each of the key levers 32 is formed with an angular arm 32 that extends downwardly and rearwardly, the tip of which projects into the respective slot 39 and contacts the depending arm of its respective cooperative intermediate bell crank lever 31 when the selected key lever is operated.

- contraction of the spring as.

bell crank-levers 31 is connected with its complementary type bar by a wire link 4 i.

Th type levers and key levers are held in position of rest (Fig. 1) by a spring 42 attached at one end to the forward arm of each of said intermediate bell cranks and at the other end to brackets t3 attached to said key lever bracket 33. The tension of the springs #2 also serves, by exerting pressure on the front edge of the depend-- ing arms of the intermediate bell cranks against the depending arms of the keylevers, to hold the key levers against a cushion stri 44 supported on the back face of the vertical wall of the comb 36 above the slots formed therein, which strips cushion the rebound of the key levers.

7 By arranging the ends of the link connection between the intermediate bell cranks and the type levers in line with the pivot point of said bell cranks, a toggle effect is provided that serves to lock the type bars in their position of rest, and also to prevent rebound of and interference between the type bars.

' The mechanism for effecting the relative shift of the segment and type bar assembly, and the platen carriage includes shift key levers l5 and 46 positioned, respectively, at the right and left of the key board. The rear-ends of said levers are connected by a transverse tie tube 4?. The levers 45 and 4e are normally held in raised posi tion by a pair of spring 45 and 46' attached, respectively, at one end to said levers 45 and 46, respectively, and, at their opposite ends, to the top wall of the comb 36. The top edge of each of said levers also cushions against the extremities I of the cushion strip 44.

The depression of either shift key lever 45 or 46 rocks the shift fram comprising said levers and the tie tube 47, and, through linkage with the arms 20, lowers the front ends thereof and raises the rear ends, thereby moving the segof the arms 20 include a pair of cushion levers,

oneof which is cooperatively associated with each of the shift key levers 45 and 46. These cushion levers take the form best shown in Figs. 3 and 4, from which it will appear that said levers each include arms 48 and t9 forming a bell crank lever pivoted at 50 to one face of vertical arms 5| formed on each of the levers 45 and it at the rear extremities thereof. The cushion members each have a third arm indicated at 52, the extremity of which is bent at an angle to form an car 53 which overlies the top edge of its respective shift lever 55 and 6. The lower extremity of each of the arms at is spring connected to the lower end of said vertical arms 5! by a spring 54. Each car 53 overlies the upper edge of its respective associated shift lever and. opposes the Upon downward movement of either of said shift levers 45 or 46, the springs 55 rockthe arms 43 rearwardly, or

' to the left in Fig. 3.

Each of the arms 29, rearward of its pivot, ha a depending arm 55. The lower extremities of said arms 55 are each bent inwardly, forming cars 56 which extend into the plane of the arms the arms 49 impinge against the cars 56 causing the arms 26 to rock and thereby impart the double shifting movements to the segment and type assembly,

a shoulder or detent at its lower extremity, which engages with a lug 58 which may be attached to a frame brace 58' of the machine. It is preferably made adjustable by being secured thereto by a binding screw. When a shift lock key lever 59, pivoted on the shift lever 36, is depressed, the end of said lever rocks against the tendency of a spring 69, which connects the lower extremity of the lever 5'1 with the shift key lever. The spring 66 normally keeps the detent disengaged upon the normal depression of the shift key levers, unless the shift lock key 59 is also depressed. After the detent is engaged by depressing the lock key lever 59, the Spring $0 also serves to disengage the detent by slight pressure on one of the shift key levers to move it downwardly slightly beyond its normal depressed position. This slight additional depression of a shift key lever to release the detent is possible without any strain on the parts, because the connection between the rear extremity thereof, and the bell crank levers 68-43 for rocking the arms 2%] is a resilient connection because of the springs 54. This construction, in effect,

provides a cushion connection between the shift tions of the segment and type bar assembly, and

platen carriage assembly are reversed from the normal or at rest position. In normal position the segment and typ bar assembly is in raised position and the platen carriage is tilted downwardly a already explained. This is the lower case printing position. When the shift occurs the segment and type bar assembly moves downwardly and the carriage platen is raised, thus, by simultaneous movement of the two assemblies, each of which makes approximately one half of the combined movement, the necessary spacing to align the upper case type to the printing line is accomplished. Since the movement of each of the assemblies is only approximately one half of the combined movement to effect the shift, and, since the assemblies counterbalance each other, the inertia of the movement, and impact at the termination of the movement is substantially reduced.

The locking of the assemblies in shifted position, in order to properly align the type for upper case printing, is effected by the shift locking mechanism, as described. that the assemblies be locked in their normal position to prevent any disalignment of printing in the lower case, and this lower case lock must be coordinated with the shift mechanism, so that it may be unlocked when the shift occurs.

The mechanism for effecting the locking of the assemblies in the initial position includes a bell crank lever associated with each of the rocking bars 20. These bell crank levers each include an arm 62, which extends forwardly and downwardly, and an arm 63 in the form as illustrated in Fig. 3 of the drawings. These levers are pivoted at 64 on a pivot support attached, respectively, to the inside face of each of the frame members I and 2. The forward extremity of each It is also preferable of the arms 62 is bent at an angle forming an ear 65, which ears extend into the plane of the ears 56 formed at the extremities of the arms 55 of the rocking bars 26. The arms .62 are normally held in angular adjustment, a illustrated in Fig. 3, in which the ears 65 are in a position to contact with the ears 56, and thereby prevent the rocking of the arms 26 when the parts are in initial position.

The means for maintaining normal adjustment of the arms 62 with the ears 65 in locking engagement with the ears 56 comprises a spring 66, one end of which is attached to the lower extremity of the arm 63, and the other end of which is connected to a spring post carried by the respective one of the side members i and 2. It will be understood that this position of the parts is maintained until the shifting mechanism is operated.

When the shifting mechanism is operated by depression of one of the shift keys 45 or 46, an angular link 6'! pivoted at 68 to the lower extremity of the respective vertical arms is moved rearwardly. The links 51 assume the angle shape best illustrated in Fig. 3, and are supported and guided in their movements by a screw 69 extending inwardly from each of the side members I and 2, respectively, said screws projecting into slots 69 in the upper extremity of the vertical arm of the links 61. The upper rear edges of the links 6! are formed as cam faces "i0, which cooperate with fingers ll, which ride on the cam faces 10 in such relation that, when the links 61 are moved rearwardly upon depression of either of the shift key levers, through the linkage just described, the cars .65 of the arms 62 are moved downwardly against the tendency of the springs 58, thereby releasing the locks or detents 56-435, so that the arms are free to rock upon continued movement of the shift key levers. This release of the detents occurs on the initial depressive movement of the shift key levers, and before the rear edge of the arm 49 of the cushion arms contacts the cars 56 to impart rocking movement to the rocker arms 2!). This is because of the fact that there is a slight space between said arms 69 and the ears 5%, thereby retarding the contact until the arms 62 are moved downwardly sufiiciently to clear the ears 55 from the ears 58.

It is preferable that the fingers ll be made sufficiently flexible in order to adjust their coni tact tips with the cam faces id to regulate the timing of the release of the lock and so that, after it has been released, the tip of the fingers H will ride on the cam faces 10 during further depression of the shift key levers, thereby holding the lock out of locking engagement during the period that the shift key lock is operative to hold the assemblies for upper case printing.

The escapement mechanism and the platen carriage is of conventional construction and, therefore, will not be specifically described. The operation of the escapement mechanism,.however, includes certain novel features to adapt it to the shift features of the machine.

This operating mechanism includes a universal bar 12 supported transversely of the machine in the rear of the depending arms of the levers 3i. The universal bar 12 carries at each extremity an arm 13, which arms are, in turn, pivotally mounted at their upper ends on the rod 38, that supports the intermediate bell crank levers 31. The arms 13 rock in slots formed at the ends of the support for the bank of the levers 31.

Since the universal bar 12 is adjacent to the depending arms of the levers 31, whenever anyone of them is rocked upon depression. of a key lever, the universal bar 12 will be rocked rearwardly. In order to adjust the contact and timing of the contact with said universal bar 12, the depending arms of the levers 31 may be bent to adjust the angular relation of their rear edges to the universal bar.

An adjustable stop limits the return movement of the universal bar 12 when the key lever is released. This stop comprises a bracket 14 carried by each of the arms 13 and positioned to contact the rear face of the key lever bracket when the universal bar is in its initial position. The part of the bracket that makes this contact may carry a cushion 15 in order to reduce the shock and noise of the contact.

An escapement trip push link 16 is pivoted at its rear end at H to a conventional escapement mechanism generally indicated at E8. The front end of the link 16 rides in a slot 19 formed in a cross brace. A plate is secured to the top face of the push link 76 to which it is secured in any suitable manner, and an arm Bl formed integrally with said plate extends upwardly at an angle and is located rearwardly of the universal bar I2. The arm 81 is adjusted at an angle, so that the contacting face thereof will remain parallel to the axis of the universal bar in its upper and lower case position.

It will be apparent that upon each depression of .a key lever, the universal bar 12 is rocked in .a rearward arc contacting the arm BI, and thereby moving the escapement trip push link '16 rearwardly, whereby, in a conventional manner, a step by step movement is imparted to the platen carriage. The angular position of the arm 81, as above explained, is of importance because the universal bar 12 moves as a unit with the segment and type bar assembly and, therefore, whenever a shift is made, the point of contact of the universal bar changes position vertically in .respect of the arm 8|. This change in relative position of the universal bar and the actuating connection with the escapement push link is compensated for by the adjustment of the angle of the arm 8|.. Therefore, irrespective of the relative position of the segment and type bar assembly and the platen carriage assembly, the escapement will be tripped at the same point in the movement of the type levers in respect of the platen.

The machine includes the usual spacing bar assembly 82 but, since this is conventional, it is unnecessary to specifically describe its elements.

The construction and operation of an embodiment of the invention will now be apparent from the foregoing description amplified by the accompanying drawings. It will also be obvious that certain modifications from the illustrative embodiment of the invention may be made without departure from the scope and principles of the invention.

Having made full disclosure of the invention, what is claimed is:

1. In a typewriting machine including a platen carriage assembly and a type bar assembly, said assemblies being pivoted for rocking movement .in a frame, an interconnection between said assemblies comprising rocking bars pivotally supported on the frame and pivotally connected to each of said assemblies, and a shift mechanism for actuating said rocking bars, whereby said assemblies are moved in opposite arcuate directions for upper and lower case printing positioning of the type bars.

2. Ina typewriting machine including a platen carriage and a segment and type bar assembly mounted for upper and lower case printing by movement in opposite directions, an actuator for imparting simultaneous movement to said assemblies, including rocker arms having fixed pivots and a rocking pivot connection with each of said assemblies, respectively, key controlled lever connections for actuating said rocker arms in one direction, and spring means actuating said arms in the opposite direction.

3. In a typewriting machine including a platen carriage and a segment and type bar assembly mounted in weight balanced relation for u per and lower case printing, rocker arms having fixed pivots and a roc ing pivot connection with said assemblies, respectively, at'opposite extremities thereof, key controlled lever connections for rocking said rocker arms in one direction, and spring means actuating said arms in the opposite direction.

4. In a typewriting machine including a platen carriage and a segment and type bar assembly mounted for movement to u per and lower case printing positions, an actuator for imparting simultaneous movement to said assemblies in opposite directions, including rocker arms having fixed pivots and rocking pivot connections with said assemblies respectively, spring means actuating said assemblies to normal position, and 5 a key controlled lever connection for actuating said rocker arms in the other direction in opposition to said spring means.

5. In a typewriting machine, in combination, a frame, a platen carriage assembly pivotally mounted on said frame, a type bar assembly pivotally mounted on said frame, rocking bars pivotally mounted on said frame and pivotally connected to each of said assemblies, and means operatively associated with said rocking bars engageable therewith for pivoting the same in one direction including a resilient connection.

6. In a typewriting machine, in combination, a frame, a platen carriage assembly mounted on said frame, a type bar assembly mounted on said frame, at least one of said assemblies being pivotally mounted, rocking bars pivotally mounted on said frame and pivotally connected to said pivotally mounted assembly, and means operatively associated with said rocking bars engageable therewith for pivoting the same in one direction including a resilient connection.

7. In a typewriting machine, in combination, a, frame, a platen carriage .assembly pivotally mounted on said frame, a type bar assembly pivotally mounted on said frame, rocking bars pivotally mounted on said frame and pivotally connected to each of said assemblies, and means operatively associated with said rocking bars for pivoting the same in one direction including a pivotally mounted shift key lever adjacent each rocking bar, a member pivotally mounted on each pivotally mounted assembly, and means operatively associated with said rocking bars for pivoting the same in one direction including a pivotally mounted shift key lever adjacent each rocking bar, a member pivotally mounted on each shift key lever engageable with its respective rocking bar, and spring means biasing each shift key lever and its associated member into a predetermined relationship.

9. In a typewriting machine, in combination, a frame, a platen carriage assembly pivotally mounted on said frame, a type bar assembly pivotally mounted on said frame, rocking bars pivotally mounted on said frame and pivotallyconnected to each of said assemblies, at least one of said rocking bars being adjustable, and means operatively associated with said rocking bars engaging therewith for pivoting the same in one direction including a resilient connection.

10. In a typewriting machine, in combination, a frame, a platen carriage assembly pivotally mounted on said frame, a type bar assembly pivotally mounted on said frame, rocking bars pivotally mounted on said frame and pivotally connected to both assemblies, each rocking bar having an extension, a shift key lever pivotally mounted on said frame in association with each rocking bar, a bell-crank lever pivotally mounted on each shift key lever including a first arm in 'a plane with the rocking bar and a second'arm normally engaging an edge of the shift key lever,

and spring means urging each bell-crank lever into position with its second arm in contact with its shift key lever, said first arm of said bellcrank lever engaging said rocking bar extension to shift said assemblies of said machine upon file'of this patent:

UNITED STATES PATENTS

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