US2675110A - Jam release means for typewriting machines - Google Patents

Description

April 13, H, c YAEGER 2,675,110

JAM RELEASE MEANS FOR TYPEWRITING MACHINES Filed Dec. 16, 1952 Y 2 Sheets-Sheet 1 all,

INVENTOR. HARP) c VAEGER A TTORNEV A ril 13, 1954 H YAEGER 2,675,110

JAM RELEASE MEANS FOR TYPEWRITING MACHINES Filed Dec. 16, 1952 2 Sheets-Sheet 2 i m if a f 09,. I? iiliifliliii=79 {if i 7i 2 7! t Z I I J2 3 A Q9 V INVENTOR. HARP) C VAEGER ATTORNEY Patented Apr. 13, 1954 JAM RELEASE MEANS FOR TYPEWRITING MACHINES Harry G. Yaeger, West Hartford, Conn., assignor to Underwood Corporation, New York, N. Y., a

corporation of Delaware Application December 16, 1952, Serial No. 326,212

6 Claims. 1

This invention relates to typewriting machines and more particularly to a device whereby type actions which have become jammed as a result of improper operation of the machine may be freed by operation of a key located either on the keyboard or in close proximity thereto. Still more particularly, the invention relates to means whereby the operator of a typewriting machine may, by operating a single key, both bring about the release of jammed type actions and backspace the paper carriage.

It is a well known phenomenon that when two or more keys of a typewriter are operated simultaneously or in too close succession, the type actions, which are designed to print at a common printing point, sometimes become jammed together with such force that their return springs are incapable of restoring them to normal position. When this occurs, it is the usual practice for the operator to grasp the upper portion of the jammed type bars, or the type heads carried thereby, and force them in a return direction to the point whereat the jam is sufiiciently loosened that the return springs are able to complete the restoring of the type actions.

The movement of the paper carriage is controlled by an escapement mechanism which allows th carriage to step forward one letter space every time a character is printed and it often happens that the escapement mechanism will be set in operation by a type action which becomes jammed, even before any printing is accomplished, and when the operator releases the jam, the carriage escapes to the next letter-space position, thus making it necessary to operate a backspace key before again operating the type action which had been jammed. While the carriage sometimes escapes after a jam, making a backspace operation necessary, sometimes it does not escape, in which case a back-space operation would be undesirable.

It is an object of this invention to provide a typewriting machine having a key or finger piece which may be selectively operated in two different manners after a type jam occurs to restore the jammed type actions either with or without a back-spacing of the platen.

It is a further object of this invention to provide a typewriting machine having means for forcibly restoring jammed type actions and a key or finger piece which, when operated to its full extent, will operate the means for forcibly restoring the jammed type actionand also operate the back-space mechanism and which, when operated to a lesser extent, will operate the means for restoring the jammed type actions without operating the back-space mechanism.

These and further objects, features and advantages will more readily appear as the descrip tion of two preferred embodiments of the invention proceeds.

Referring now to the drawings:

Figure 1 is a side elevational view, partly in section, of a portion of a manual typewriter embodying the invention,

Figure 2 is a view showing part of the mechanism of Figure 1 in operation,

Figure 3 is an exploded perspective view of the mounting and operating means for a bail member employed in releasing jammed type actions,

Figure 4 is a side elevational View, partly in section, of a portion of an electric typewriter embodying the invention,

Figure 5 is a view of a portion of the mechanism shown in Figure 4 and showing the condition of the parts after a jam is released and before the back-space mechanism is operated, and

Figure 6 is a view similar to Figure 5 but showing the condition of the parts after the key has been moved far enough to operate the back-space mechanism.

The manual machine shown in Figures 1, 2 and. 3 comprises a frame, generally indicated at It and only partially shown, upon which is mounted a plurality of type actions each of which comprises a key lever H connected by a link I 2 to a pivotally mounted sub-lever it which in turn is connected by a pull link I14 to a type bar It mounted for swinging movement in a type basket 56. Each key lever is provided with an operating key ii and, as is known, depression of a key H causes the corresponding type bar It to swing upwardly about its pivot and through a type guide it to bring the type head it) thereof into contact with an inked ribbon, not shown, and force it into contact with the paper carried about a roller platen 2!].

If two or more keys I"! are operated simultaneously or in too close succession, a type bar l5 corresponding to each operated key will swing upwardly and attempt to pass through the type guide, but since the type guide is only wide enough to permit one type bar at a, time to pass through, the upper ends of the actuated type bars will be pressed together or jammed, as indicated in chain-dotted lines in Figure 1, with such force that return springs 2|, Which normally restore the type actions to their home positions after each typing operation, are unabl to restore them. When this condition occurs, the usual practice is for the operator to grasp the upper ends of the jammed type bars or the type heads I9 and force them back to the point where the jam is released. As will presently appear, the present invention provides means whereby the operator. may release the jam by merely depressing a key.

The platen is mounted for rotation on a carriage generally indicated at 22, which carriage is mounted on front and rear rails 23 and 2% respectively, for transverse movement in letterfeed and return directions. As is well known and need not be shown, the carriage 22 is moved in letter-feed direction by a spring drum and its movement is controlled by an escapement mechanism which permits the carriageto move forward one letter space distance each time a type action is operated. As is also well known, the escapement will often be operated when a type action jam, as indicated in chain-dotted lines in Figure 1, occurs. Since jammed type actions usually cause the type barto fail to print or print with a much lighter impression than desired, it is often necessary to back-space the carriage after a jam before typing is resumed.

Most, if not all, commercial typewriters are provided with a back-space mechanism whereby, by operating a key on the keyboard, the operator can cause the carriage to move a letter-space distance in a return direction. The particular backspace mechanism shown in Figures 1 and 2 is fully described in the patent to Helmond, No. 1,414,?38, and comprises a pawl 25 pivotally and loosely connected at 25 to a carrier 21 which in turn is pivoted on a stationary pivot 28. A link 29 is pivoted at its upper end to an arm to of the pawl 25 and at its lower end to an arm 3i fixed to a rockshaft, 32. A spring 33 extending between the arm 3! and a stationary part 3'4 normally holds the pawl 25 and its carrier 21 in the position shown in Figure l. A key lever is fixed at its rearward end to the rockshaft 32 and on its forward end is provided with a back-space key 36'. Depression of the back-space key results in drawing down the link 2%, which relieves the pawl carrier 21 of the urge of the spring 33 and permits a leaf spring 3?", which is attached to said pawl. carrier and bears at its upper end against a stationary pin 38, to rock the carrier forward until the upper end thereof bears against an escapernent rack 35 of the carriage 22-, at which time the upper end of the pawl 25 comes in contact with the teeth of said rack, as shown in Figure 2. Further depression of the key 36 swings the pawl 25 in the direction to move the rack, and consequently the carriage 2-2, in a return direction the distance of one letter-space, as more fully ex plained in the Eel-mend patent referred to above. Even though anoperative back-space mechanism has been shown and briefly described hereinabove, it will be understood that the particular back-space mechanism is not of the essence of this invention and that the invention as claimed hereinafter does not necessarily contemplate the use of this particular back-space mechanism.

Pivotally mounted on brackets d0 secured to the upper portion of the frame It, is a bail comprising a pair of arms M, only one of which is shown, between which extends a bridging member 42. The bridging member extends transversely of the'machine and is normally out of the. operating paths. of: the type actions, as indicated. in Figure 1. On the left hand side of the. machine, the bail arm 41b is. provided with a cam slot. 43

and the bracket 40 is provided with a straight guide slot M. A link 45 is pivotally connected at its lower end to the back-space key lever 35 and at its upper end is provided with a pin it extending therethrough. One end of the pin 35 is positioned within the guide slot 64 and the other end within the cam slot 43. With this arrangement, it will be evident that depression of the back-space key 38, will cause the pin 46, in cooperation with the cam slot 43 and guide slot M, to swing the bail counterclockwise, whereupon the bridging memher '32 thereof will press against the sub-levers Id of any type actions which have become jammed and forcibly restore said type actions to their home positions. So that both ends of the bail will work in unison, even though the link 45 operates on only one of the arms cl, a link 4'1 is pivotally connected to each arm A! of the bail. Each link 41 is also pivotally connected to an arm d8 fixed to a transverse shaft 49, so that as the left hand arm 4! of the bail is moved by the link 45 the right hand arm, not shown, of said bail will be moved by its link fill.

In operation, the early part of the movement of the back-space key affects the back-space mechanism only to the extent of relieving the pawl carrier 2? of the urge of the spring 33 and when the pawl 25 starts to pick up the rack 39, the operator can feel the resistance of the carriage. It is only when the back-space key is operated to its full extent that the carriage is actually moved back a letter-space distance. The movement of the back-space key required to condition the back-space mechanism is approximately one-half the total distance that the key must be. moved to actually back-space the carriage. The jam release bail and the operating linkage therefor are so arranged that the first part of the total movement of the back-space key will completely operate the bail and restore the jammed type actions. When two or more type actions become jammed, the operator depresses the back-space key to the point whereat the back-space mechanism picks up the carriage and that movement of the key will restore the jammed type. actions. If the carriage does not escape when the jam is released, the operator does not depress the key any farther, because the carriage will be in proper position for typing to be resumed. If the carriage is observed to escape when the jam is released, the operator merely completes the depression of the back-space key to its full extent, whereupon the carriage will be moved back a letter-space distance in return direction, to proper position for the next character to be typed.

In Figures 4, 5 and 6, the invention is shown embodied in an Underwood electric typewriter. Since the machine itself is familiar to those engaged in the typewriting machine field, only those parts directly concerned with the present invention have been shown. Each type action comprises a type bariil mounted in a type basket M in such manner that it may be swung upwardly through a type guide 53 for printing on a. sheet carried by a roller platen 54. Each type bar has connected thereto one end of a draw link 55, the other end of which isconnected to a pivotally mounted sub lever 56. As is known, the sub-levers, 5d are operated. by levers- 51 when an actuator; partially shown at. 53, connected thereto is selectively moved into. engagement with a fluted shaft, not shown, by operation oi; the

usual keys of the typewriter keyboard, also not shown.

The platen 54 is mounted for rotation in a carriage 59, which in turn is suitably mounted for letter-feed and return movement transversely of the typewriter. The carriage is provided with a rack 60 with which is meshed a pinion 8| fixed to the upper end of a shaft 62, to the lower end of which is fixed a toothed escapement wheel 63. The escapement wheel 83 forms a part. of an escapement mechanism, not shown, but which, as is known, permits the carriage to move forward one letter-space distance each time a type action is operated to position the carriage for the printing of the next character.

Since the type guide 53 is only wide enough to permit one type bar at a time to pass therethrough, when two or more type actions are operated simultaneously or in too close succession, the upper ends of the bars 50 become jammed together, as indicated in chain-dotted lines in Figure 4, and fail to restore under the action of their return springs 64, in which event the sub-levers 56 are held approximately in the positions shown in chain-dotted lines in Figure 4.

Pivotally mounted on the frame of the machine is a restoring bail comprising a pair of arms 65, only one of which is shown, extending between which is a bridging member 66, which extends transversely of the machine and is normally out of the operating paths of the sub-levers 56 of the type actions. Pivotally connected to one of the arms 65 is one end of a link 61, the other end of which is pivotally connected to one arm of a two-armed lever 88 pivotally mounted at 69 on the framework of the machine. To the other arm of the lever 68 is pivotally connected a key lever 19 provided with a key H located adjacent the typewriter keyboard. The key lever 19 is mounted for back-and-forth sliding movement on a stationary pin 12 which extends through an arcuate slot 13 in said key lever. The slot 13 is provided with a detent shoulder 14, and a light spring 15 urges the key lever in a direction to cause the shoulder H to strike the pin 12 when the key is operated. Movement of the key H from the position shown in Figure 4 to the position shown in Figure 5, wherein the shoulder H strikes the pin 72, causes the bridging member 66 of the release bail to press against the sub-levers 56 of any type actions which may have become jammed as a result of improper operation, to thereby forcibly restore said type actions to their home positions.

As hereinabove explained in connection with the description of the machine shown in Figures 1, 2 and 3, a jamming of the type actions will sometimes result in the carriage escaping to the next letter-space position and sometimes the types will become jammed together before they have moved far enough to operate the escapement, in which case, of course, the carriage does not escape. If, when the key H is operated to the extent that the shoulder 14 moves against the pin 12 to thereby free the type jam, it is observed that the carriage does not escape, the operator merely releases the key whereupon a spring 18 connected to one of the arms 65 of the bail restores the bail and the key to the position shown in Figure 4.

If, as the type jam is released, it is observed that the carriage escapes to the next letter-space position, the operator need merely press the key H a little harder, whereupon the shoulder I4 will slip past the pin 12 and the restoring bail will be rocked an additional distance to bring a pin 11 secured thereto into contact with a cam surface 18 of a back-space operating linkage so that the carriage will be moved a letter-space distance in return direction, as will now be explained.

The back-space mechanism shown in the drawing is identical with that shown and described in the patent to Helmond, No. 2,294,662, and since this particular back-space mechanism is merely one of a number of different back-space mechanisms which may be employed in carrying out this invention, it need not be described in great detail. In general, the back-space mechanism comprises a toothed link 19 pivotally connected to one end of an arm and so mounted that when the arm 89 is rocked in a clockwise direction from the position shown in Figure 4, said link will rotate the escapement wheel 63 in the direction and to the degree necessary to cause the pinion 6| to move the rack 60 and the carriage one letter-space distance in a return direction. The arm 8|] is fixed to one end of a shaft 8|, which end is mounted in a stationary bracket 82. The other end of the shaft BI is mounted in an elongated slot 83 and normally held at the lower end of said slot by a relatively heavy spring 84. Connected to the end of the shaft 8| which is mounted in the slot 83, is an arm 85 urged by a spring 86 in a counterclockwise direction to maintain a roller 81 carried thereby in contact with a, cam 88. The cam 88 is loosely mounted on a constantly rotating shaft 89 and has pivoted thereto. a pawl 90 urged by aspring 9i in the direction to engage a nose thereof with the teeth 92 of a member which rotates with the shaft 89. The nose of the pawl is normally held out of engagement with the teeth 92 by a yoke member 93 which has a nose which cooperates with a shoulder on said pawl as shown in Figures 4 and 5. The yoke member 93 is pivoted on a stationary pivot 94 and i connected by a pin-and-slot connection 95 to a lever 98 pivotally mounted on the framework at 91. A spring 98 urges the lever 96 about its pivot in a direction to maintain the nose of the yoke 93 in cooperative engagement with the shoulder of the pawl 90. The roller 81 on the arm 85 rests in a depression in the surface of the cam 88 to prevent the spring 9| from rotating said cam in 93. This rotation of the cam 88 rocks the arm 85 and consequently th arm 89 in a clockwise direction to cause a back-space movement of the platen, as aforesaid. When the key H is released and restored to its normal position by the spring 18, the spring 98 rocks the lever 98 back to its normal Figure 4 position, whereupon the nose 99 releases the pawl 99 and permits a further rotation of the cam 88 sufficient to bring it back to its normal position. This additional rotation of the cam 88 does not aflfect the backspace mechanism because the shape of the cam 88 is such that the arm 85 has completed its 7 rocking motion by the time the cam has rotated to the position to bring the shoulder of the pawl 90 into engagement with the nose 99 of the yoke 93. The purpose of the second nose 99 of the yoke 93 is to insure that only one revolution is given to the cam 88 tor each operation of the back-space key and that consequently the carriage is moved backward only one letter-space distance for each operation of said key, all as more fully explained in the patent to Helmond,

No. 2,294,662,- referred to above.

Thus, it will be seen that movement of the key H to its full extent will cause the forcible restoration of any type bars which. may have become jammed and also cause a back-spacing of the carriage. On the other hand, a partial operation of the key H will cause a release of the type jam without a back-spacing of the carriage.

Having thus described two embodiments of the invention, what is claimed is:

I; In a typewriting machine, a platen carriage movable in letter-feed and return directions, a plurality of spring-restored type actions individ ually operable to print at a common printing point and which will become jammed and fail to restore if operated in too close succession, means to restore forcibly any type actions which have become jammed, means for imparting a letter-feed increment of movement to said carriage in a return direction, a manipulative member movable from a first position to a second position and to a third position, means efiective by the movement of said manipulative member to said second position to operate said means to restore forcibly any type actions which have become jammed, and means effective by movement of said manipulative member to said third position to'ope-rate the means for imparting a letterfeed increment of movement to said carriage in a return direction. 7

2.. In a typewriting machine, a platen carriage movable in letter-feed and return directions, a plurality of spring-restored type actions individually operable to print at a common. printing point and which will become jammed and fail to restore if operated in too close succession, means to restore forcibly any type actions which have become jammed, back-space means for moving said carriage letter-space distances in a return direction, a finger piece movable to different extents, means operable upon movement of said finger piece to a first extent to operate the means to restore forcibly any type actions which may have become jammed, and means operable upon an additional extent of movement being imparted to said finger piece to operate said back-space means.

3. In a typewriting machine, a platen carriage movable in letter-feed and return directions, a plurality of spring-restored type actions individually operable to print at a common printing point and which Will become jammed and fail to restore if operated in too close succession, a bail extending transversely of the machine and normally clear of the operating paths of said type actions but operable to restore forcibly any type action failing to restore, back-space means for moving saidcarriage letter-space distances in areturn direction a manipulative member movable to: different extents, means operatively 8 conncoting'said manipulative member to said ball and operative by movement of said manipulative member to a first extent to operate said bail'a'nd thereby cause the forcible restoration of any type action which has failed to restore, andmeans operable by movement of said manipulative member an additional extent to operate said back-space means.-

4. In a typewriting machine, a platen carriage movable in letter-feed and return directions, a plurality of spring restor'ed type actions individually operable to print at a common printing point and which will become jammed and fail to restore it operated in too close succession, re storing means to restore forcibly any type actions which have becomejammed, back space means for imparting letter feed increments of movement to said carriage in a return direction,- a manipulative member movable from a first position to a second position and to a third position, means-effective by the movement of said manipulative member to said second position to operate said restoring means, and means operati've by said restoring means when said manipulative member is moved to said third position to operate said back-space means.

5 In a typewriting machine, a platen carriage movable in letter-feed and return directions, a plurality of spring-restored type actions indi vidu'ally operable to print at a common printing point and which will become jammed and fail to restore if operated in too close succession, a transversely extending restoring bail for said type actions normally out of their operating paths and comprising laterally spaced arms swinga-bly supported in. the machine and a bridging member extending between said. arms, back-space means for moving said carriage letter-space dis tances in a return direction, a manipulative member movable to different extents, means 0-peratively connecting said manipulative member to said; restoring Fbail'operative by movement of said manipulative member to a first extent to operate said bail and thereby cause the forcible restoration of any type action which has tailed to restore, and means operable by said restoring bail when said manipulative member is moved. an additional extent to operate said back-space III-83115.

(i. In a typewriting machine,- a platen carriage movable in letter-feed and return directions, a plurality of spring-restored type actions individually operable to print at a common printing point and which will become jammed and fail to restore if operated in too close succession, restoring means. to restore forcibly any type actions which have become'jammed, back-space means for imparting letter-feed increments of movement to said carriage in a return direction, a depressib'le key lever and an operating key carried thereby, means interconnecting said key lever and said restoring means and operable by partial depression of said key lever to operate said restoring means, and means interconnecting said key lever and said baclvspace means and operable by complete depression or said key lever to operate said. back-space means.

Noreferences cited.

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