US2289531A - Typewriting and like machine - Google Patents

Description

R. G. THOMPSON TYPEWRITING AND LIKE MACHINES July 14, 1942.

Filed Aug. 29, 1959 2 Sheets-Sheet l July 14, 1942. R. e. THOMPSON TYPEWRITING AND LIKE MACHINES Filed Aug. 29, 1939 2 Sheets-Sheet 2 Patented July 14, 1942 2,289,581 TYPEWRITING AND LIKEMACHINE Russell G. Thompson, West Hartford, Conn, as-

signo toBemlntto m Inc., Buffalo, N. Y.,

r a corporation of Delaware Application August 29, 1939, Serial No. 292,461 8 Claims. (Cl. 197-44) My invention relates to typewritin'g and like machines, and more particularly to improved case shift mechanism therefor;

The main object of my invention, generally stated, is to provide improved means of the character specified which is simple, reliable and highly effective in operation.

Another object of my invention is to provide improved case shift mechanism wherein the shiftable member may be easily shifted from one case position to the other and with greater certainty that the shiftable member is fully operated to each extreme shifted position. 4

Another object of myinvention is to provide such case shift mechanism wherein the shiftable member in each extreme case shifted position is securely held against displacement due to rebound, jars, vibration and the like.

Another object of my invention is to provide resilient means in such case shift mechanism which acts on the shiftable member at each extreme case shifted position thereof to take up any looseness or play in the actuating connections and thereby insure definite shifted positions of the shiftablemember and prevent vibration thereof in such positions.

Still another object of my invention is to provide cooperating adjusting means permitting accurate adjustment of each of the case shifted positions of the shiftable member as well as accurate adjustment of the holding means for the shiftable member to accord with the adjustment of the shifted positions thereof.

To the above and other ends which will hereinafter appear, my invention consists in the features of construction, arrangements of parts and combinations of devices set forth in the following description and particularly pointed out in the appended claims.

In the accompanyingdrawings. wherein like reference characters indicate corresponding parts of the different views:

Fig. 1 is a front, vertical, transverse sectional view taken through the central portion of a typewriting machine, and illustrating a sufficient number of parts thereof to show my invention in its embodiment therein.

Fig. 2 is a fragmentary, fore and aft, vertical sectional view taken on line 2-2 of Fig. l and viewed in the direction of the arrows at said line.

Fig. 3 is a fragmentary, detail sectional view showing certain parts of the case shift actuating means as they appear in a different caseshifted position.

Fig. 4 is a fragmentary, horizontal, sectional ,view of a detail of the case shift actuating means, the view being taken on line 4-4 of Fig. 2 and viewed in the direction of the arrows at said line.

I have shown my invention in the present instance embodied in a Remington Model No. 17 typewriting machine wherein a type basket is movable for case shifting. While the features of the present invention were designed primarily for embodiment in this machine and may be included therein without modifying or materially modifying the existing structural features thereof, it should be understood that the invention is not restricted to use in such machine but may be employed in a machine of the type having a platen or platen carrying carriage which is movable for case shifting. In other words, my invention may be applied to different types of machines wherein there is provided a relative case shifting movement between the type bars and platen, and when I refer herein to a case shiftable part or member, I intend such term to have a generic meaning applicable to either a type basket, to a platen, or to any member which is arranged for case shifting movement.

The drawings show only so much of the construction of the Remington Model No, 1'! machine as is necessary to arrive at an understanding of the present invention in its embodiment therein. The case shift mechanism is mounted within a frame comprising side plates ill which are interconnected by :cross members, one of which is a cross member l2 shown in part in Figs. 1 and 2. The case shiftable member in the present machine is a type basket which includes a type bar segment M of the usual construction carrying type bars 15 mounted in companion radial slots l6 and on a common fulcrum wire l1. The type bars ii are operated in the usual manner by suitable type actions including key levers and sub levers (not shown) each of which is connected to operate the companion type bar I! through a pull link l8 as shown in Fig. 2. Each type bar I! carries a lower case type l9 and an upper case type 20, and when the segment II is in its elevated position shown in Figs.

1 and 2, the lower case type I9 is moved to the printing point on a platen 2i with the aid of a type guide 22 in the usual manner. The type guide 22 is fixedly secured at 23 to the segment ll which may be shifted downward from the normal position as will be hereinafter described to allow the upper case type 20 to be moved to the same printing point on the platen 2|.

The upper portion of the segment i4 is guided 55 on the cross member I! for substantially vertical case shift movement. Thus, left and right hand lateral extensions 24 and 26 on the segment are provided with ball race members 26 and 21 respectively which are fixedly secured thereto by headed screws 28. Each of the members 26 and 21 are grooved as shown in Fig. 2 to provide raceways for companion anti-friction bearing balls 36, which balls arealso received in companion vertically disposed raceways formed by grooves in stationary race members 32 and 33 arranged opposite the race members 26 and 21 respectively. The stationary race members 32 and 33 are received in companion channels in opposite end portions of the cross member l2, and the position of each of the race members32 and 33 in the companion channel is adjustably determined by associated fore and aft adjusting screws 35 and by associated lateral adjusting screws 36. In

each instance the screws 35 and 36 are arranged above and below the center of the companion raceway. This arrangement permits each of the stationary race members 32 and 33 to be adjusted forward and rearward relative to the cross member l2 and also to or from the companion mov able race members 26 and 21, and in each instance this adjustment is obtained both above and below the center of the companion raceway. By such adjustment absolute parallelism may be effected and maintained between each raceway in the members 32 and 33 and the associated raceways in the members 26 and 21. An accurate line of case shift movement of the segment l4 may therefore be afforded and yet the segment is firmly guided against any transverse displacement. In the present instance, the heads of the screws 28 are sufiiciently long to prevent the bearing balls 38 from falling or riding 'out of their companion raceways.

Referring to Fig. 2 it will be seen that the extensions 24 and 25 of the segment l4 are provided with depending arm 38 and 38 respectively which are pivotally connected to companion arms 42 and 43 of a rock shaft 44. The pivotal connection between each of the depending segment arms and the companion rock shaft arm is formed by an associated shoulder screw 45 which is retained in the companion rock shaft arm by a nut 46. The rock shaft 44 is pivotally supported at its ends on shoulder pivot screws 48 received in tapped openings in the associated side plates l8 and retained in position by lock nuts 49 threaded thereon.

The segmentt I4 is thus guided for substantially vertical case shift movement, the bearing balls 36 guiding the upper portion thereof on the cross member I2, whereas the lower end of the segment is guided in its shifting movement by the pivotal connection thereof with the arms 42 and 43 of the rock shaft 44. It will be apparent that during. such case shifting movement, the arcuate travel of the extreme lower end of the segment I 4 about the axis of the rock shaft 44. will cause a very slight pivotal movement of the segment about the single bearing ball 38 at each side thereof.

The weight of the type basket including the segment I4 and parts carried thereby is counterbalanced by a contractile spring 54 connected to each of the arms 38 and 38 of the segment and extending upward to a companion bracket 55 secured at 56 to the associated side plate Ill. The combined effective forces of the two springs 54 is suillcient to normally maintain the segment I4 and parts carried thereby in its elevated posi-' tion shown in Figs. 1 and 2, as will hereinafter more clearly appear.

The case shift movement of the segment I4 is controlled in the present instance by the usual manually operable keylever arrangement which is operatively connected to the segment by improved means which will hereinafter be described in detail. Thus, a rock shaft 66 is pivotally mounted, by means not shown, at each end on the associated side plate It, and a case shift key lever 62 is fixedly secured to each end portion of this rock shaft 66. Although only the left hand case shift key lever 62 is shown in the drawings, it will be understood that this key lever and the parts carried thereby will be duplicated at the right hand end of the rock shaft 60. The central portion of each of the case shift key levers 62 is guided by a vertically disposed slot in a guide comb 63 which is secured at 64 to an inwardly extending ear on each of the side plates l8, and the forward end portion of the key lever 62 is provided with a case shift key 65.

Each of the case shift key levers 62 is provided with case shift locking devices which include a shift lock lever 68 pivotally mounted thereon at 68 and provided with a key I6 at its forward end. A contractile spring 12 connects the lock lever 68 with the shift lever 62 and tends to normally maintain the lock lever in its upper position on the shift lever shown in Fig. 2 where a laterally projecting lug 13 on the lock lever 68 engages the lower edge of the shift lever 62. A latching pawl I4 is pivotally mounted at 15 on the shift lever 62, and a spring 16 normally retains the pawl 14 in its position shown in Fig. 2, where a rearward extension thereof engages the laterally projecting lug 13 of the lock lever 68.

A depression of the case shift lock key 18 initially causes a relative pivotal movement between the lock lever 68 and the shift lever 62 until a laterally projecting lug TI on the locking lever 68 engages the upper edge of the shift lever '62. This initial relative movement between the levers 68 and 62 moves the lug l3 downward to allow the pawl 14 to move under the force of the spring 16 to a position where the upper end thereof engages a plate 18 adjustably mounted by screws 86 on the guide comb 63. Continued downward movement of the key 10 moves levers 68 and 62 in unison through the lug 11 until the upper end of the pawl 14 is shifted by the spring 16 beneath the lower edge of the plate 18, so that when pressure on the lock key 16 is relieved, the pawl 14 is effective to hold the shift key 62 in its depressed position.

In order to release the case shift lever 62 from this locked position, a downward pressure may be exerted on the shift key 65 at either side of the machine to relieve the frictional engagement of the end of the pawl 14 with the edge of the plate I9. This allows the spring 12 to move the pawl 14 to its released position through the lug 13 and thereby permits the shift lever 62 to return to its normal position when the pressure on the shift key 65 is released.

. The means provided in accordance with the present invention for operatively connecting the case shift key lever mechanism with the segment l4 includes an upwardly extending arm 84 on the left hand case shift key lever 62, which arm is provided with an opening at its upper end receiving the forward end of a pull link 85. An expansion spring 86 is provided on the pull rod 85 which engages a nut 81 threaded on the forward end of the rod 85 and bears against the front surface of the arm 04 to normally hold the arm in engagement with a second nut 08 also threaded tuating arm 90 and is retained therein by a spring clip member 9I received in a groove at the end of the rod 05.

An eccentric bearing means is provided for adjustably mounting the actuatingv arm 90 for pivotal movement on the left hand side plate II. Thus, a headed bearing member 94 enters a bear-. ing opening at the, upper end of the actuating arm 90, and a retaining screw 95 passes through an eccentric opening in this bearing member 94 and is threaded into a tapped opening in a spacing member 90 secured at 91 (see Fig. 1) to the left hand side plate I0. Thus, the bearing member 94 may be turned around the eccentrically disposed holding screw 95 to vary the pivotal axis of the actuating arm 90 relative to the associated side plate I0, and when the desired position of this pivotal axis is attained, the screw 95 may be tightened to securely clamp the bearing member 94 against said side plate.

The lower portion of the actuating arm 90 is providedwith a bearing opening receiving the body portion of a headed pin 99 carried by a link I00, which link is in turn provided with a bearing opening receiving the body portion of a headed pin IOI carried by the upper on of a guide arm I02. The lower end of the guide arm I02 is adjustably mounted for pivotal movement on a bracket I03 by an eccentric bearing means comprising parts I04 and I05 which may be the same as parts 94, and 95 respectively which are employed to adjustably mount the actuating arm 90.

The bracket 103 is securely attached at I01 (Fig. 1)' to the left hand side plate I0, and the headed bearing member I04 is received in a bearing opening in the guide arm I02 with the retaining screw I05 passing through an eccentrically disposed opening in said bearing member and threaded into the bracket I03. A link I09 is pro-; vided for connecting the segment I4 with the upper end of the guide arm I02, the upper end of this link being connected by a pivot screw IIO to a rearwardly extending bracket III fixedly secured at II2 (see Fig. 1) to the left hand depending arm 30 of the segment I4. The lower end of the link I09 is pivotally connected to the arm I02 and to the link I at the junction thereof by an opening in the link I09 which receives the body portion of the headed pin IOI so that the link I09 is disposed between the link I00 and the arm I02 as will be seen in Fig. 4. A contractile spring I I extends between a rearwaridly extending pin II5 on the cross member l2 on the machine frame and a rearward extension III of the actuating arm 90, and thus exerts a force on the actuating arm tending to return it to the position shown in Fig. 2.

An integral downwardly extending portion I20 is bent atright angles to the body portion of the actuating arm 90 to form an enlarged stop surface. At the normal position of the actuating arm 90 shown in Figs. 2 and 4, the rear face of the enlarged stop portion I20 engages a padded stop formed by a disc I22 of felt or any suitable resilient material, which disc is securely attached to a threaded holding member I29 received in a tapped opening in an angular lug I24of the bracket I03. 7 v

This stationary resilient stop means I22--I23 the part I23 until the axis of the-pivot pin IN is disposed one line between the axis of the pivot screw land the axis of the adjustable be. ring member I04. The adjustable bearing member I04 may then be turned about its eccentric retaining screw I05 until the correct elevated position of the segment I4 is obtained for writing lower case characters. In other words, the bearing member I04 is turned to raise or lower the type segment I4 through the guide arm I02 and link I09 in their straightened position until a position of the segment I4 is obtained wherein the lower case type l9 are on their feet" at the printing position, or where the top and bottom portions of the lower case type produce a substantially even imprint. This adjusted position of the bearing member I94 may be retained by tightening the holding screw I05.

A slight lateral shift of the pivotal axis of the guide arm I02 may be caused by this adjustment of the bearing member I04, and accordingly the resilient stop means I22-|23' may be given a slight further adjustment to again restore the alignment of the axes of the pivots H0, MI and I04. After the final adjustment of the stop means I22l23 is attained, a nut I25 may be tightened on the threaded member I23 against the surface of the lug I24 to securely hold this position of adjustment.

The guide arm I02 and the link I09 thus constitute a toggle device which is straightened at the lower case position of the segment I4 and any force tending to displace the segment from this position acts directly against the dead center oi the guide arm I02. The toggle device I02I09, however, may be easily operated from this straightened position by a manual depression of the shift key 55 at either side of the machine to effect a forward movement of the actuating arm 90 through the arm 84 and pull rod 05. This forward movement of the actuating arm 90 is stopped when it reaches the position shown in Fig. 3 by the engagement of the forward surface of the enlarged stop portion I20 with adjustable resilient stop means which may be similar to the stop means I22I23 previously described. Thus, a felt disc I20 is secured to a threaded holding member I29 threaded into a tapped opening in an angular lug I30 on the bracket I03.

It will be clear that the forward movement of the actuating arm 90 acts through the link I 00 l to cause the guide arm I02 to be moved forwardly around its bearing member I04, and the arm I02 acts through the link I09 to pull the segment I4 downward against the force of the springs 54. Thus, the segment I4 may be shifted downward against the force of the springs 54 by pressing the case shift key 55 at either side of the machine, and the segment may be retained in this shifted position by pressing either of the associated shift lock keys 10 to allow the latch pawl 14 to engage the lower edge of the lock plate 19 in the manner previously described. During this shift movement of the segment, the actuating arm 90 is operated to its position of arrest shown in Fig. 3 without compressing or materially compressing the spring 00 on the pull rod 85. In order to release the pawl 14, however, a downward presfor the actuating arm 90 is adjusted by turning sure may be applied to the shift key 55 which is sufficient to slightly compress the spring 86, This disengages the upper end of the pawl 14 from the lower edge of the plate 19 which allows the spring 12 to operate the pawl 14 to its released position through the lug I3.

The forward position of arrest of the actuating arm 90 is adjusted by turning the threaded member I29 in the lug I30 until the axis of the pivot 99 is disposed in a line between the axis of the bearing member 94 and the axis of the pivot IOI. The lowered position of the segment I4 for writing upper case characters may then be adjusted by turning the bearing member 94 upon its eccentric holding screw 95 so that the upper case type 20 are on their feet at the printing position. In other words, the downward shifted position of the segment I4 may be adjusted by turning the bearing member 94 until the upper case type 20 print evenly at their upper and lower edges, and this adjusted position of the bearing member 94 may be retained by tightening its holding screw 95.

A slight lateral shift of the pivotal axis of the actuating arm 90 may be caused by the adjustment of the bearing member 94, and accordingly a slight further adjustment of the stop means I28-I29 may be necessary to restore the alignment of the axes of the pivots 94, 99 and MI. The final adjusted position of the stop means I28I29 may be retained by tightening a nut I3I on the threaded member I 29 to engage the surface of the lug I30.

The actuating arm 90 and the link I thus constitute a second toggle device which assumes a straightened position when the segment I4 reaches its lowered position for writing upper case characters, and any force tending to displace the segment from such position acts against the dead center of the actuating arm 90. The segment I4, however, as well as the case shift key lever mechanism and the actuating connections are returned from this lowered position shown in Fig. 3 to their normal elevated position shown in Fig. 2 by the force of the springs 54 which acts directly on the segment I4 and accordingly acts against the pivotal dead center of the actuatingarm 90 in its position shown in Fig. 3. The provision of the spring II5, however, prevents the segment from being locked in its elevated position inasmuch as the spring II5 acts on the actuating arm 90 to move it out of its dead center position when the manual shifting force acting thereon through the pull rod 85 is relieved. After the arm 90 is thus moved from its dead center position, the springs 54 are effective to return the segment, key lever mechanism and associated parts to their normal elevated position shown in Fig. 2.

In accordance with the present invention, improved resilient means are provided for opposing the latter part of the movement of the segment I4 to each of its case shift positions. Thus, any looseness in the actuating connections is taken up by the movement of the segment to each of its case shifted positions against the force of said resilient means. The resilient means provided for this purpose in the present instance acts to oppose the latter part of the relative pivotal movement which occurs between the depending arm 39 of the segment I4 and the arm 43 of the rock shaft 44 during the case shift movements thereof.

Referring particularly to Figs. 2 and 3, it will be seen that the arm 43 extends at I35 beyond the pivotal connection thereof with the depending arm 39 of the segment I4. A flat leaf spring or resilient steel strip I36 is retained at its central portion by a screw I3I threaded into a tapped opening in the arm 43 above the pivot screw 45, and the spring strip I 36 extends forward above the central portion of the arm 43 as well as rearward over the arm extension I 35. The rearward portion of the strip I36 is provided with side portions I 36 which extend downward along the side edges of the arm extension I35 to prevent the strip from turning about the screw I3'I. The front and rear ends of the spring strip I36 are normally supported and biased upwardly by associated coiled expansion springs I40, the front spring being seated in a depression I in the arm 43, while the rear spring is seated in a depression in the extension I35, as may be seen in Fig. 2. The springs I40 are sufiiciently strong tonormally hold the associated ends of the strip I36 upward out of engagement with the arm 43 and extension I 35.

A rearward integral extension I 44 is provided on the depending arm 39 of the segment I 4, and a tapped opening in this extension I44 receives a contact screw I45. At the position of the parts shown in Fig. 2, the contact screw I45 is adjusted in the extension I44 to engage the rearward portion of the spring strip. I36 and to move it against the force of the associated coil spring I40 to a position where it either engages or nearly engages the upper surface of the arm extension I35. This adjusted position of the contact screw I45 may be retained by a nut I46 threaded thereon to bear against the upper surface of the extension I 44.

A similar forward extension I49 on the depending arm 39 of the segment I4 is also provided with a tapped opening which receives a contact screw I50. When the segment I4 is shifted downward for writing upper case characters as shown in Fig. 3, the contact screw I50 is adjusted to engage the forward portion of the spring strip I36 and to move it against the force of the associated coil spring I40 to a position where it either engages or nearly engages the upper surface of the arm 43. Likewise this adjusted position of the contact screw I50 may be retained by tightening a nut I 5| thereon to bear against the upper surface of the extension I49.

When the segment I4 is shifted downward from its position shown in Fig. 2 to its position shown in Fig. 3, it will be clear that the contact screw I50 does not engage the associated end of the spring strip I36 until the segment nearly reaches its extreme lowered position, and accordingly no resistance is offered by the associated coil spring I40 during the greater part of this case shift movement. However, as the actuating arm and the link I00 approach their straightened relation shown in Fig. 3, the contact screw I50 engages the forward end of the spring strip I36 so that the straightening of the toggle device 90I00 moves the segment to its final position of arrest against the force of the associated coil spring I40. In this manner, the segment I4 is retained in its lowered position under the tension of the forward spring I 40 which takes up any looseness in the pivotal connections IIO, IOI, 99 and 94. This arrangement entirely prevents any possibility of vertical vibration of the segment while upper case characters are being written.

It will likewise be clear that during the return movement of the segment from its position shown in Fig. 3 to its position shown in Fig. 2, the contact screw I45 does not engage the rearward portion of the strip I36 until the segment nearly reaches its extreme upper position, and accordingly no resistance is offered by the rearward coil spring I40 throughout the greater part of this return shift movement. However, as the link I09 ward portion of the strip Ill and the final move-y ment of the segment ll to its elevated position is effected against the force of the rearward coil spring I by the straightening of the toggle device lot-I02. Inthis manner, the segment is retained in its elevated position under the tension of the rearward coil spring which takes up any looseness in the pivotal connections Ill,- llil and HM. -Thus, any possibility of vertical vibration of the segment is also prevented while lower case characters are being written.

It will be seen that I have thus provided a simple and highly effective case shift mechanism wherein toggle devices are employed to hold the shiftable member in each case shift position against the tension of resilient means acting on the shiftable member to take up any looseness in the toggle connection which might aflord vibration of the shiftable member. In this arrangement, it will be noted that the force of this resilient means acting on the shiftable member is directed against the pivotal dead center of one of the toggle devices at each case shift position so that the force of the resilient means does not tend to displace the shiftable member from; either of its extreme shifted positions.

It will be noted moreover that the present case shift mechanism includes two toggle devices connected in series so that one toggle device straightens as the other toggle device breaks. This arrangement affords a v'erydesirable operating characteristic inasmuch as the rapidly increasing mechanical advantage afforded by each of the toggle devices as it is moved toward its straightened position results in an appreciable decrease in the effort required to effect the final movement of the shiftable member to each extreme position. Thus, the maximum efiort is required to move the shiftable member through the intermediate portion of its travel to provide greater certainty that the shiftable member reaches its extreme shifted position in each instance. It will also be clear that this arrangement permits the shiftable member to be retained in its shifted position by a minimum pressure on the case shift keys.

It will further be apparent that practically no noise is produced by the arrest of the shiftable member in either of the case shifted positions thereof, and the shiftable member cannot rebound from either of such shifted positions. This is due to the arrangement whereby the force incident to the arrest of the shiftable mmiber is absorbed by the straightening of the toggle devices and any rebound force is directed against the pivotal dead center thereof. The provision of individual adjusting means for each of the toggle devices afiordsan accurate independent adjustment of each extreme case shifted position of the shiftable member, and the provision of padded adjustable stops for the actuating means affords a substantially noiseless arrest thereof at positions which may be adjusted to allow the associated toggle device to assume a straightened position, regardless of the adjustment of the shifted positions of the shiftable member.

Various changes may be made in the construction, and certain features therein may be omitted without departing from my invention as it is defined in the accompanying claims.

What I claim as new and desire to secure by Letters Patent is:

1. In a typewrlting machine, the combination of a machine frame, a case shiftable member mounted for case shifting movement relative thereto, a guide arm pivotally mounted on said frame, a link connecting said arm with said case shiftable member and normally disposed in alignment with said guide arm, an actuating arm pivotally mounted on said frame, a second link connecting said actuating arm with said guide arm: spring means acting on said actuating arm to normally hold it out. of alignment with said second link, key controlled means operatively connected with said actuating arm and arranged to cause movement thereof into alignment with said second link to simultaneously move said guide arm out of alignment with said first mentioned link and thereby shift said case shiftable member, resilient stops for limiting the movement of said actuating arm in each direction, and resilient means acting to supply tension to said case shiftable member at each extreme case position thereof.

2. In a typewriting machine, the combination of a case shiftable member mounted for shifting movements, a rock shaft operatively connected with said shiftable member for guiding the latter in its case shift movements, resilient means acting between said shiftable member and said rock shaft to oppose movement of the shiftable member to each extreme case shifted position, and actuating means for said shiftable member including a first pair of toggle elements operable when straightened to move said shiftable member to one extreme caseshifted position against the force of said resilient means, and a second pair of toggle elements interconnected with said first pair of toggle elements and operable when straightened to move said shiftable member to the other extreme case shifted position against the force of said resilient means. I

3. In a typewriting machine, the combination of a case shiftable member mounted for shifting movements ,a rock shaft having arms pivotally connected to said shiftable member, resilient means acting between one of the arms of said rock shaft and said shiftable member to oppose the final movement only of said shiftable member to each extreme case shifted position, and actuating means for said shiftable member including a first pair of toggle elements operable when straightened to move said shiftable memher to one extreme case shifted position against the force of said resilient means, and a second pair of toggle elements operatively connected to said first pair of toggle elements and operable when straightened to break the first pair of tosgle elements and to move said shiftable member to the other extreme case shifted position against the force of said resilient means.

4. In a typewriting machine, the combination of a machine frame, a case shiftable member mounted for shifting movements in said frame, an arm pivoted on said frame and pivotally connected to said shiftable member, resilient means acting between said shiftable member and said arm for opposing relative pivotal movement between the shiftable member and the arm, and actuating means for said shiftable member in cluding a first toggle device arranged when straightened to move the shiftable member to one extreme position against the force of said resiiient means, and a second toggle device operatively connected to said first toggle device and arranged when straightened to break the first toggle device and to move the shiftable member to the other extreme position against the force of pose movement of said shiftable member to either extreme case shifted position, and actuating means for said shiftable member including a first toggle device arranged when straightened to move the shiftable member to one extreme position against the force of said spring means, and a second toggle device operatively connected to said first toggle device and arranged when straightened to break the first toggle device and to move the shiftable member to the other extreme position against the force of said spring means.

6. In a typewriting machine, the combination of a machine frame, a case shiftable member mounted for shifting movement relative to said frame, spring means acting on said shiftable member to normally hold it in one case shift position, a first pair of toggle elements connected between said shiftable member and said frame and disposed in straightened relation when the shiftable member is in said case shift position, a second pair of toggle elements connected between said frame and the junction of said first pair of toggle elements, manual operating means connected to said second pair of toggle elements for straightening said second pair of toggle elements and breaking said first pair of toggle elements to thereby shift said shiftable member to the other case shift position against the force of said spring means, and resilient means for breaking said second pair of toggleelements when the manual operating force thereon is removed to al-v low said spring means to return said shiftable member. 1

7. In a typewriting machine, a type bar segment, mounted for substantially vertical case shift movement, a returning spring acting on said segment to normally hold it in an elevated position for writing lower case characters, a case shift key lever, and means operative by said key lever for shifting said segment, to a lowered position for writing upper case characters. said means including a toggle device operative by said key lever to a straightened position to shift said segment against the force of said returning spring, spring means acting on said toggle device to move it from said straightened position, and resilient means acting to supply tension to said segment only at the extreme lowered position thereof.

8. In a typewriting machine, the combination of a machine frame, a case shiftable member mounted for shifting movement relative to said frame, a pair of toggle elements connected between said shiftable member and said frame and disposed in straightened relation when the shiftable member is in one case shift position, resilient means acting directly on said shiftable member to supply tension thereto only at the extreme case shift position thereof, and spring means acting on said toggle elements to normally hold the latter in straightened relation and thereby hold said shiftable member in said case shift position against the force of said resilient means.

RUSSELL G. THOMPSON.

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