US3643776A

US3643776A - Line space adjustment device for use with typewriter

Info

Publication number: US3643776A
Application number: US784073A
Authority: US
Inventors: Yoshitsugu Tanaka
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 1967-12-20
Filing date: 1968-12-16
Publication date: 1972-02-22
Anticipated expiration: 1989-02-22

Abstract

A line space adjustment device for a typewriter comprising a set of ratchet wheels having different pitches to provide different line spacing. Separate engaging levers are selectively engageable with each ratchet wheel, and each of the levers is operated by a common electromagnet and associated linkage to provide a selective desired spacing. Line spacing is also provided by a manually operated release lever.

Description

United States Patent Tanaka [54] LINE SPACE ADJUSTMENT DEVTCE FOR USE WITH TYPEWRTTER [72] Inventor: Yoshitsugu Tanaka, Tokyo, Japan [73] Assignee: Kabushiki Kaisha Ricoh, Tokyo, Japan [22] Filed: Dec. 16, 1968 [21] Appl. No.: 784,073

[30] Foreign Application Priority Data Dec. 20, 1967 Japan ..42/81758 [52] U.S.Cl. ..197/114 R, 197/127R [51] 1111. C1. ..B4lj 19/76 [58] FieldofSearch ..197/114, 121, 122, 123, 127, I

[56] References Cited UNITED STATES PATENTS 1,096,646 5/1914 Steele ..197/128 1,158,818 11/1915 Lockwood ..197/123 Feb. 22, 1972 1,188,875 6/1916 Allard ..197/114 X 1,227,847 5/1917 Smith I .1 197/135 1,357,194 10/1920 Stickney 197/122 X 1,849,494 3/1932 Last ..l97/l 14 1,921,453 8/1933 Carroll..... 197/114 X 2,086,945 7/1937 Pfeiffer.... ..197/128 2,153,208 4/1939 Rabenda ..197/127 X 2,493,411 1/1950 Lanegan et al ..197/133 X 3,326,348 6/1967 1 Cralle et al. ..197/114 Primary ExaminerErnest T. Wright, Jr. Att0rney-Burgess, Ryan & Hicks [5 7] ABSTRACT A line space adjustment device for a typewriter comprising a set of ratchet wheels having different pitches to provide different line spacing. Separate engaging levers are selectively engageable with each ratchet wheel, and each of the levers is operated by a common electromagnet and associated linkage to provide a selective desired spacing. Line spacing is also provided by a manually operated release lever.

10 Claims, 13 Drawing Figures PATENTEDFEB 2 2 I972 SHEET 1 0F 5 PATENTEDFEB 2 2 1972 sum 2 0F 5 FIG.3

FlG.4c FlG.4d

FIG.40 FlG4b ATTORNEYS PATENTEDFEB 22 I972 3. 643 776

sum

3 or 5 4 INVENTOR LINE SPACE ADJUSTMENT DEVICE FOR USE WITH TYPEWRITER BACKGROUND OF THE INVENTION ratchet wheels having different pitches are actuated by independent electromagnets so that the typewriter mechanism is considerably complicated and large in size.

In view of the above, the present invention has for its object to actuate selectively two ratchet mechanisms by a single electromagnet from the exterior ofthe device.

SUMMARY OF THE INVENTION The present invention relates to an improvement on a line space adjustment device of a typewriter in which a ruled or lined paper to be typewritten is pressed against the platen; the initial writing position is determined by coarsely or finelydi splacing the paper with respect to the platen; the paper is automatically advanced by a space corresponding to-one line space every time one line is typewritten; and the typewritten paper is automatically pulled out of the typewriter just by depressing a pushbutton. The important aspect of the present invention resides in the fact that two linespacing ratchet mechanisms are selectively actuated by'a single electromagnet instead of two electromagnets so that two different line spacings may be effected.

According to one preferred embodiment of the present invention, a plurality of ratchet wheels having the same diame ter but different pitches are fitted coaxially and in side-by-side relation with respect to each other over a driving shaft which is rotated in unison with a paper feed roller for positioning a paper to a predetermined position with respect to the platen. The driving shaft is manually rotated so that a coiled spring FIG. 8 is a side view illustrating the operating steps of the mechanisms shown in FIG. 7;

FIG. 9 is a perspective view ofa releasing lever; and I FIG. 10 is a perspective view ofa bifurcated lever.

DESCRIPTION OF THE PREFERRED EMBODIMENT In an embodiment of the present invention shown in FIG. 2, reference numeral 1 designates a stationary frame U-shaped in cross section, to which is loosely fitted a shaft 3 having a fine adjustment knob 3a for fine adjustment of the attachment position of a ruled or lined paper 2 shown in FIG. 1. The shaft 3 extends to the right in FIG. 2 and has a feed roller 3b carried at the extended portion thereof. The feed roller 3b is adapted to feed the paper 2. Another roller 4 made of rubber is carried by a shaft 3 in parallel and opposite relation with the feed roller 3b and is pressed against the outer peripheral surface of the roller 3b so that the paper 2 is held between the feed roller 3b and the rubber roller 4 andan adjoiningpair of

feed rollers

3b and 4. The fine adjustment knob 3a is provided with a slot 3c (See FIG. 2) extending axially of the knob 3a and adapted to loosely slide on a pin 3d which is securely fixed to the shaft the slot 3c. Furthermore, the knob 3a is adapted to rotate with connected to the driving shaft is wound up whereby the v reverse rotation is imparted to the driving shaft by the returning force of the coiled spring. Another shaft coaxial with the driving shaft carries rotatably a pair of reverse rotation preventive levers provided with catches respectively, an engaging lever having an engaging pawl at one arm end thereof and a lever adapted to cooperate with said engaging lever. The above-described levers are all drivingly interconnected with each other. A plurality of rotary cams each out of phase with respect to each other are adapted to be actuated from the exterior of the device so that said pair of catches can be selectively engaged with the ratchet wheels. By the selection of the ratchet wheels, line spacings can be selected.

Other objects and advantages of the present invention will become apparent from the following description of a preferred embodiment thereof taken in conjunction with the accompanying drawing.

BRIEF DESCRIPTION OF DRAWING FIG. 1 is a perspective view illustrating a stack of ruled or lined papers used in the typewriter of the present invention;

FIG. 2 is a plan view illustrating the essential mechanisms of one embodiment of the typewriter of the present invention;

FIG. 3 is an enlarged front view with a part being broken away illustrating the essential mechanisms shown in FIG. 2;

FIGS. 4(a) to 4(d)- are perspective views of reverse rotation preventive vlevers and engaging levers of the ratchet mechanism incorporated in the typewriter of the present invention;

FIG. 5 is a side view of the essential mechanisms in the direction along the chain line V-V of FIG. 3;

. FIG. 6 is a side view illustrating the operating steps of the ratchet mechanism shown in FIG. 5;

FIG. 7 is a side view of the essential mechanisms in the direction along the chain line VII-VII of FIG. 3;

the rotation of shaft 3.'Against the inner end portion of theknob 3a is abutted one end ofa bellcrank lever 12b which has its fulcrum point 12 pivoted to the outer wall of the stationary frame 1 and is urged toward the inner end portion of the knob 3a by a spring 12a. The other end of lever 1212 includes a pin 12c which engages with a bifurcated lever 12d of a shifter 12 in the form of a bellcrank lever, which will be described in detail hereinafter.

A sleeve 5 'is loosely, coaxially fitted over the shaft 3 between the opposing inner walls of the stationary frame 1, and two

ratchet wheels

6 and 7 having the same diameter but different numbers of teeth and a toothed wheel 8 are coaxially carried by this sleeve 5. One end of the sleeve 5 is formed as an opened or receiving cone clutch element 50 of a cone clutch as shown in FIG. 3. A cone-shaped engaging member 9 which engages with the opened or receiving cone clutch element 5a is loosely fitted over the shaft 3 and is provided with a peripheral'groove 9a.'A disk 10 having a flanged portion 10' integral with the shaft 3 is disposed adjacent to the engaging member 9 and an expansion spring 11 is interposed between the engaging member 9 and the disk 10 so that the engaging member 9 of the clutch generally has a tendency of engaging with the opened or receiving element 5a. A'pin 9c securely fixed to a flange 9b of the engaging member 9 of the cone clutch is fitted loosely into a hole 9 provided in thedisk 10 so that the engaging member 9 and the shaft 3 may be rotated in unison. Therefore, when the shifter'l2 which is fitted into the peripheral groove 9a of the engaging member 9 is rotated clockwise by movement of the knob 3a to the right against the

springs

11 and 12a in FIG. 2, the cone clutch is disengaged through the above-described levers.

A coiled spring 13 is disposed in a barrel 13 attached to the outer surface of one wall of the stationary frame I and the inner end of the coiled spring 13 is fixedly secured to a shaft 14 disposed in parallel with the shaft 3. The shaft 14 has a tendency to rotate due to the force of coiled spring 13.

Toothed wheels

15 and 16 are coaxially carried by the shaft 14 as shown in FIG. 2, and the toothed wheel 15 engages with the toothed wheel 8 while the toothed wheel 16 is in mesh with a toothed wheel 17 mounted on shaft 17' rotatably disposed inwardly .of the wall of the stationary frame 1 (See FIG. 2).

A shaft 18 having a flange I8 is loosely journaled by the stationary frame I in parallel with the shaft 3 and has a toothed wheel 19 loosely fitted over the shaft 18. This toothed wheel 19 is in mesh with the'toothed wheel 17. As shown in FIG. 2, one side of the toothed wheel 19 is formed intoan engaging member 19a having a conical outer surface. A flanged engaging disk 20 carried by the shaft 18 in adjacent relation to the engaging member 19a is permitted to slide in the axial direction of the shaft 18 and to rotate in unison with the shaft 18. The clutch comprising the above-described engaging member 190 and the engaging disk 20 is normally in powertransmission engagement relation by means of a spring 21 interposed between the stationary frame 1 and the engaging disk 20. A hand lever 23 is attached to the end of the shaft 18 and is integral with a lever 24. A pawl 25 is attached to the free end of the lever 24 and resiliently engages with the teeth of a ratchet wheel 22 fixedly carried by the shaft 18. When the hand lever 23 is rotated, the coiled spring 13 within the barrel 13 is wound and simultaneously the toothed wheel 8 is rotated through the above-described

clutch

19a, 20 and

intermediate transmission gears

15, 16 and 17.

Shafts

26 and 27 are journaled by the stationary frame 1 as shown in FIG. 3 in parallel with the shaft 3, and

disk cams

26a and 26b (See FIG. 7) which are out of phase by 180 with respect to each other are carried at the intermediate portion of the shaft 26. The shaft 26 extends beyond the stationary frame 1 toward the left and at the end of the shaft 26 is attached a knob (not shown), which can be manually rotated from the exterior of the device.

Loosely fitted over the shaft 27 are a pair of

levers

28 and 29 for preventing the reverse rotation (which will be described in more detail hereinafter with reference to FIGS. 4(a) and 4th) and referred to as nonreversing levers"), an engaging lever 30 (FIG. 4(c)), an engaging lever 31 (FIG. 4(d)) and a releasing lever 32 (FIG. 9) for releasing the catches described hereinafter of the

nonreversing levers

28 and 29 from the

ratchet wheels

6 and 7.

As shown in FIG. 4(a), the nonreversing lever 28 includes a pair of opposed openings 28flocated on an axis 28g and has three arms, comprising a first arm 28a integral with a second arm 28]). The base portion in the vicinity of the fulcrum point of the nonreversing lever 28 is U-shaped in cross section and a third arm 28c is made integral with one side of the base portion. The first arm 28a terminates in a catch pawl and will be referred to as catch" hereinafter. The catch 28a engages with the teeth of the ratchet wheel 6 while the second arm 28b contacts with the outer peripheral surface of the disk 26a. The third arm 28c is provided with an arcuate slot 28d which is located at the offset portion of the lever 28 and whose center is the same as the center of shaft 27 about which the lever 28 rotates. The nonreversing lever 28 has a tendency of rotating in the counterclockwise direction about the shaft 27 by a tension spring 33a connected to the front wall 1a of the stationary frame 1 as shown in FIG. 5 The shape of the nonreversing lever 29 is similar with that of the lever 28, that is it includes a pair of opposed openings 29f located on an axis 29g, and a first arm 29a, a second arm 29b and a third arm 29c of the lever 29 are directed in similar directions as the first arm 28a, the second arm 28b and the third arm 280 of the nonreversing lever 28 as shown in FIGS. 4(a) and 4(b). Elements of the nonreversing lever 29 whose functions are similar to those of the corresponding parts of the nonreversing lever 28 are designated by the similar suffixes as those of the lever 28. The first arm 29a ofthe nonreversing lever 29 mounted on shaft 27 is also adapted to engage with the teeth of the ratchet wheel 7 while the second arm 2% contacts with the outer peripheral surface ofthe cam disk 26b. When the arm 29b contacts with the cam disk 2617. the arm 290 that is the catch disengages from the ratchet wheel 7.

The base portion of an engaging lever 30 is U-shaped in cross section and includes a pair of opposed openings 30d located on an axis 300 as shown in FIG. 4(a) and is loosely fitted over the pivot or shaft 27 inwardly ofthe base portion of the nonreversing lever 28, and an engaging pawl 30a is provided at one arm end of the engaging lever 30. The engaging pawl 30a is normally disengaged from the teeth of the ratchet wheel 6 by means of the tension spring 34a connected to the front wall 111 ofthe stationary frame 1 as shown in FIG. 5.

The other arm end 30b of the engaging lever 30 is adapted to make contact with the side edge ofa first arm 35a ofa bifurcated lever 35 having openings 35f pivotal on axis 352 (See FIG. 10) which will be described in more detail hereinafter. At the offset portion ofthe engaging lever 30 is provided an arcuate slot 30c whose center is the center of the axis 30? about which the engaging lever 30 rotates. A pin 28c which is fixedly secured to the offset portion of the nonreversing lever 28 is loosely fitted in this arcuate slot 301 and is normally positioned at the right end ofthe slot 300 as shown in FIG. 5.

The base portion of an engaging lever 31 is U-shaped in cross section and includes a pair of opposed openings 31d located on an axis 312 as shown in FIG. 4(d) and loosely fitted over the pivot or shaft 27 inwardly of the base portion of the nonreversing lever 29. One arm 31b of the lever 31 is slightly bent and is pressed against the side edge of the second arm 35b of the bifurcated lever 35 (See FIG. 3) by means ofa tension spring 34b connected to the front wall la of the stationary frame 1 (See FIG. 7). At the offset portion of the lever 31 is provided an arcuate slot 310 whose center is the center of the axis 316 about which rotates the lever 31. A pin 292 secured to the offset portion of the nonreversing lever 29 is loosely fitted into the arcuate slot 31c, and is normally positioned at the right end of the arcuate slot 31c as shown in FIG. 7. It should be noted that the shape of the lever 31 is similar to that of the engaging lever 30 as is clear from FIG. 4(d), but the lever 31 is not provided with an engaging pawl as is the lever 30 which is provided with the engaging pawl 30a. However, the offset portion 31a (as shown in FIGS. 7 and 8) is connected to tension spring 34b in a manner similar to the connection of spring 3411 to lever 30.

The releasing lever 32 provided with a pushbutton 32' is rotatably disposed between the base portions of the pair of nonreversing levers 28 and 29, and as shown in FIGS. 7 and 9 the releasing lever 32 has openings 32d located at one end on an axis 32e for providing a tendency of rotating in the counterclockwise direction about the pivot or shaft 27 by means of a spring 36 connected to the front wall 1a of the stationary frame 1. A bent element 32a which extends from an intermediate portion of the upper edge of the lever 32 and is pro vided with a covering member 320 is pressed against the lower side surface ofa traverse frame 32a U-shaped in cross section which is disposed at a predetermined position of the front wall 10 of the stationary frame 1 so that the releasing lever 32 is normally held horizontally. At the offset portions on both sides in the vicinity of the base portion ofthe releasing lever 32 are provided

pins

32b and 32c, which as shown in FIGS. 5 and 7 are loosely fitted in the

slots

28d and 29d of the

third arms

28c and 29c respectively. When the catch pawl 28a engages with the teeth of the ratchet wheel 6 (See FIG. 5), the pin 32b is positioned in the lowermost position of the slot 28d and the catch pawl 29a is disengaged from the teeth of the ratchet wheel 7 while the pin 320 is positioned at the uppermost position of the slot 29d. When the pawl 29a engages with the teeth of the ratchet wheel 7, the relative positions of the

pins

32b and 32c with respect to the

slots

28d and 29d are reversed.

As shown in FIG. 3, an inverted box-shaped bracket 37 is attached to the inner walls of the stationary frame 1 and an energizing coil 38 for an electromagnet is disposed within bracket 37. When the coil 38 is energized, a plunger 39 fitted into the coil 38 coaxially thereof is moved inwardly of the coil 38 against the tendency of the plunger 39 to normally extend outwardly of the coil 38. A shaft 40 is journaled between the lower edges of

sideplates

37a and 37b whose upper edges are attached to the bracket 37 and which extend downwardly therefrom at an angle thereto. The bifurcated lever 35 is pivoted to the shaft 40. The first arm 35a of the bifurcated lever 35 contacts the arm 30b of the engaging lever 30 while the second arm 35b contacts the arm 31b of the lever 31. The third arm 35c of the bifurcated lever 35 is pivoted to one end of the plunger 39 by a pin 41, and extends further upwardly in such a manner that the end of this extended arm 350 is slightly bent so as to form a bent member 35d. A plate 37c bent from the bracket 37 has a horizontally extending bent portion 37d to which is threaded an adjustment screw 42, which contacts the bent member 35d. Therefore, adjusting suitably the adjustment screw 42 adjusts the distance between the extreme ends or addendums of the teeth of the ratchet wheel 6 and the engaging pawl 30a.

Next the mode of operation of the device of the present in vention having the structure as described hereinabove will be described. First, the ruled or lined paper 2 shown in FIG. 1 is fed between the pair of

rollers

3b and 4 in FIG. 3 from the upward position. The coarse adjustment lever 23 in FIG. 2 is rotated toward the operator so that the pawl which is attached to the free end of the arm 24 rotates the ratchet wheel 22. The rotation of the ratchet wheel 22 rotates transmission gears 19, 17,16, 15 and 8 through clutch 19a, 20. The toothed wheel 8 rotates the feed roller 3b integral with the shaft 3 through the other clutch 5a, 9 so that the ruled or lined paper 2 is caused to move downwardly coarsely. At the same time, the coiled spring 13 within the barrel 13 attached at the end of the shaft 14 which is integral with the toothed wheel 16 is wound up so that the returning force for rotating the toothed wheel 8 is stored. The force is stored because the catch 28a is in engagement with the ratchet wheel 6 which is integral with the toothed wheel 8, and the toothed wheel 8 is not permitted to rotate in the reverse direction.

In order to align the first line of the ruled or lined paper 2 with the first writing position of the platen not shown, the paper 2 is moved downwardly by the coarse adjustment operation as described above. Thereafter, the knob 3a is pushed toward the direction indicated by the arrow in FIG. 2 so that the shifter 12 in engagement with the peripheral groove 9a of the clutch 9 is displaced toward the left against the

springs

11 and 12a, whereby the conical opened or receiving member 5a integral with the sleeve 5 is disengaged from the engaging member 9. When the fine adjustment knob is rotated by the fingers, the paper 2 held between the

rollers

3b and 4 is movable upwardly or downwardly.

When the first line has been typewritten after the ruled or lined paper 2 was set to the predetermined position and when the platen together with the paper 2 is displaced toward the left in FIG. 3 and reaches the end, a switch (not shown) is actuated so that the coil 38 is energized so as to attract the plunger 39 inwardly of the coil 38 against the normally outward position of the plunger 39. Consequently, the bifurcated lever pivoted to the end portion of plunger 39 is rotated in the counterclockwise direction about the shaft or pivot in FIG. 6 so that the engaging lever 30 in contact with the first arm 35a of the bifurcated lever 35 is caused to rotate about the pivot or shaft 27 in the clockwise direction against the spring 340. The engaging pawl 30a of the engaging lever 30 is pushed toward the path of the rotation of the ratchet wheel 6 and simultaneously the pin 28a of the nonreversing lever 28 which is fitted in the slot 300 of the engaging lever 30 is rotated against the spring 33a by the upper end of the slot 300 so that the catch pawl 28a integral with the pin 28e is disengaged from the ratchet wheel 6. Therefore, the ratchet wheel 6 is caused to rotate by the returning force of the coiled spring l3 about the shaft 3 until the catch 30a engages with the ratchet wheel 6 in FIG. 5 so that the catch 28a is displaced from the teeth between which has been held the catch 28a to a position where the catch 28a can engage with the next tooth of the ratchet wheel 6. When the coil 38 is deenergized, the nonreversing lever 28 as well as the engaging lever 30 are caused to rotate about the shaft 27 in the reverse direction by means of the

springs

33a and 34a so that the catch 28a engages again with the teeth of the ratchet wheel 6. On the other hand, the catch 30a is disengaged from the ratchet wheel 6 so that the catch 30a returns from the position shown in FIG. 6 to the position shown in FIG. 5. Consequently, the ratchet wheel 6 causes the feed roller 3b to reverse by the returning force of the coiled spring 13 so that the paper 2 is fed or advanced by the distance corresponding to one line space. Then the typewriting position of the types (not shown) is set to the initial typewriting position of the advanced new line of the paper 2. The above-described operation is cycled for each line spacing. When typewriting of the paper 2 is completed, the releasing lever 32 indicated by the chain line in FIG. 5 is pushed down so that the pin 32b disposed in the vicinity of the base portion of the releasing lever 32 disengages the catch 2812 from the ratchet wheel 6, whereby the feed roller 3b is reversed at once by the returning force of the coiled spring 13, thereby pulling out the paper 2 upwardly from the feed roller 3b. When the releasing lever 32 is pushed down, the pin 282 of the nonreversing lever 28 is permitted to freely displace within the slot 300 of the engaging lever 30 so that the engaging lever 30 is not actuated at all.

Next, the case in which the ruled or lined paper 2 having rules or lines spaced apart from each other by a distance or space two times that of the paper 2 is typewritten will be described hereinafter.

First, prior to the insertion of the paper 2 between the feed roller 3!; and the roller 4 from the upward position, the shaft 26 which is integral with the knob disposed outwardly of the device is rotated through so that the cam disk 26a that is integral with the shaft 26 causes the second arm 28b of the nonreversing lever 28 to rotate about the shaft 27 in the clockwise direction against the spring 33a. Simultaneously, the catch 28a is disengaged from the ratchet wheel 6 and the second arm 29b of the nonreversing lever 29 is disconnected from the outer peripheral surface of the cam disk 26]), whereby in FIG. 7 the nonreversing lever 29 is caused to rotate about the pivot or shaft 27 in the counterclockwise direction by the spring 33b, thereby engaging the catch 290 with the ratchet wheel 7 having the teeth whose pitch is two times that of the ratchet wheel 6. Therefore, the angle of intermittent rotation of the ratchet wheel 7 is two times that of the ratchet wheel 6.

As described above, when the paper 2 is inserted from the upper position between the feed roller 31; and the roller 4 and when the coarse adjustment lever 23 is pulled toward the operator,

clutches

5a, 9 and 19a, 20 and the intermediate transmission gears 15, 16 and 17 are driven so that the roller 3b integral with the shaft 3 is rotated, thereby coarsely moving downwardly the paper 2. Simultaneously, the coiled spring 13 attached to the end of the shaft 14 integral with the toothed gear 16 is wound up so that the returning force for rotating the toothed wheel 8 is stored. In this case, the reverse rotation of the toothed wheel 8 is prevented by the catch 29a in engage ment with the ratchet wheel 7. Thus, the returning force stored in the coiled spring 13 may be reserved. In order to align the line of the paper 2 with the writing position of the platen, the knob 3a is pushed to the direction indicated by the arrow in FIG. 2 as described hereinabove, against the spring 12a so that the shifter 12 is actuated, thereby disengaging the engaging member 9 from the conical opened or receiving member 5a. Thereafter, by rotating the fine adjustment knob 3a, the paper 2 held between the

rollers

3b and 4 may be slightly moved upwardly or downwardly.

When the first line of the paper 2 is typewritten after the ruled or lined paper 2 has been set to the predetermined position in front of the platen and when the platen together with the paper 2 is shifted toward the left in FIG. 3, the switch (not shown) is actuated so that the coil 38 of the electromagnet is energized, whereby the plunger 39 is attracted. Consequently, the bifurcated lever 35 pivoted to the end of plunger 39 is rotated in the counterclockwise direction about the shaft 40, so that the engaging lever 30 as well as the lever 31 in contact with the first arm 35a of the bifurcated lever 35 are rotated in the clockwise direction against the

springs

34a and 34b about the shaft or pivot 27, whereby the engaging pawl 30a is extended into the passage of rotation of the ratchet wheel 6. Simultaneously, the pin 29:: of the nonreversing lever 29 is caused to rotate against the spring 33b by the upper end of the slot 310 of the lever 31 so that the catch 29a integral with the pin 296 is disengaged from the ratchet wheel 7. Therefore, the ratchet wheel 7 rotates about the shaft 3 by the returning force of the coiled spring until the catch 30a engages with the ratchet wheel 6 as shown in FIG. 7. The catch 2% is disengaged from the teeth ofthe ratchet wheel 7 and is displaced to a position where the catch 29a can engage with the next tooth of the ratchet wheel 7. When the coil 38 is deenergized, the pawl 30a of the engaging lever 30 makes a reverse rotation about the shaft or pivot 27 by the spring 34a, so that the pawl 30a is disengaged from the ratchet wheel 6, while the catch 29a of the nonreversing lever 29 makes a reverse rotation about the shaft on pivot 27 due to the influence of spring 3317 and makes a sliding contact with the tooth ofthe ratchet wheel 7 in reverse motion and finally engages with the teeth of the ratchet wheel 7 so that the reverse rotation of the ratchet wheel 7 is stopped, thereby returning the ratchet wheel 7 from the position shown in Fig. 8 to that shown in FIG. 7. Consequently, the ratchet wheel 7 causes the reverse rotation of the feed roller 3b made integral with the shaft 3 through the clutch 5a so that the paper 2 is fed or advanced by the distance equal to two line spaces. The above-described operation is cy cled, and when typewriting of the whole paper 2 is completed, the releasing lever 32 is shown in FIGv 7 is pushed down against the spring 36 so that the pin 320 of the lever 32 disengages the catch 29a from the ratchet wheel 7, whereby the feed roller 3b is rotated in the reverse direction at once by the returning force of the spring 13, thereby pulling out the paper 2 between

feed rollers

3b and 4.

As described hereinabove, according to the present invention, a pair of ratchet wheels each having a different pitch of the teeth are incorporated in the device and are selectively engageable in order to select or set the line space of two types of papers having different spaced-apart lines or rules, and the intermittent rotation of the ratchet wheels are made by a single elcctromagnet instead of two electromagnets so that the ratchets can be assembled in the device compact in size, whereby the whole structure of the device can be made advantageously simple in construction.

The present invention has been described so far in particular reference to the preferred embodiment thereof, but it will be understood that variations and modifications can be effected within the true spirit of the present invention as described hereinabove and as defined in the appended claims.

1 claim:

1. In combination with a typewriter having roller means comprising a pair of rollers between which typewriter paper is moved in selectively determined increments for line spacing, a line space adjustment device comprising a frame;

a first shaft journaled in said frame and having said roller means mounted thereon;

a pair of ratchet wheels mounted on said first shaft;

windable first spring means mounted on said frame for rotating said first shaft when wound;

a second shaft journaled in said frame and spaced from said first shaft;

a pair of holding levers mounted on said second shaft and respectively contacting said ratchet wheels to prevent rotation;

said holding levers being selectively positionable so that when one holding lever is in contact with its respective ratchet wheel, the other holding lever is out of contact with its respective ratchet wheel;

a pair of engaging levers mounted on said second shaft, each one of said engaging levers being in operative engagement with one ofsaid holding levers, respectively;

a lever having two end portions arranged in bifurcated form, each end portion positioned to operatively contact one of said engaging levers; and

an actuating element for pivoting said bifurcated lever to rotate at least one of said engaging levers and one of said holding levers out of contact with one of said ratchet wheels to allow said spring means to rotate said first shaft.

2. A combination according to claim 1, in which a third shaft is journaled in said frame, a pair of cam elements is mounted on said third shaft, said cam elements being selectively rotatable to each contact a holding lever for rotation into the holding contact with its respective ratchet wheel, and second spring means is provided to exert biasing force for said holding contact.

37 A combination according to claim 2, in which the cam elements are out of phase with respect to each other to provide a different amount of movement to said holding levers when rotated.

4. A combination according to claim 2, in which a first gear is mounted on said first shaft, a fourth shaft is spaced from said first shaft and has said first spring means mounted thereon to be wound when said fourth shaft is rotated, 21 second gear is mounted on said fourth shaft to intermesh with said first gear, and manual means is operable to rotate said fourth shaft thereby rotating said first shaft and associated roller means and simultaneously winding up said spring means.

5. A combination according to claim 1, in which said ratchet wheels are connected to a sleeve rotatably mounted on said first shaft, an engageable clutch is mounted on said first shaft and connected with said sleeve, and manual means is provided to engage said clutch so that incremental rotation of said ratchet wheels provides the incremental rotation of said first shaft and associated roller means.

6. A combination according to claim 1, in which said actuating element is an electromagnet having a movable plunger therein, the bifurcated lever has a bent portion at the other end, said bent portion being contacted by said plunger upon energization of said electromagnet to rotate said bifurcated lever.

7. A combination according to claim 2, in which said holding levers comprise a first lever having a first extending arm contacting its respective ratchet wheel, a second extending arm radially spaced from said first extending arm and contacting one of said cam elements, and a third extending arm radially spaced from said first and second extending arms and having a projecting pin formed thereon and a slot formed therein.

8. A combination according to claim 7, in which said holding levers comprise a second lever having a first extending arm contacting its respective ratchet wheel, a second extending arm radially spaced from said first extending arm and contacting the other of said cam elements, and a third extending arm radially spaced from said first and second extending arms and having a projecting pin formed thereon and a slot formed therein.

9. A combination according to claim 8, in which said pair of engaging levers each have a slot formed therein to receive the respective pin from one of said holding levers.

10. A combination according to claim 9, in which a release lever is provided, each release lever extending partly outside of said frame with the remainder thereof extending within said frame to pivot on said second shaft, said release lever including opposing pins on either side thereof respectively engageable in said slots ofsaid holding levers.

Claims

1. In combination with a typewriter having roller means comprising a pair of rollers between which typewriter paper is moved in selectively determined increments for line spacing, a line space adjustment device comprising a frame; a first shaft journaled in said frame and having said roller means mounted thereon; a pair of ratchet wheels mounted on said first shaft; windable first spring means mounted on said frame for rotating said first shaft when wound; a second shaft journaled in said frame and spaced from said first shaft; a pair of holding levers mounted on said second shaft and respectively contacting said ratchet wheels to prevent rotation; said holding levers being selectively positionable so that when one holding lever is in contact with its respective ratchet wheel, the other holding lever is out of contact with its respective ratchet wheel; a pair of engaging levers mounted on said second shaft, each one of said engaging levers being in operative engagement with one of said holding levers, respectively; a lever having two end portions arranged in bifurcated form, each end portion positioned to operatively contact one of said engaging levers; and an actuating element for pivoting said bifurcated lever to rotate at least one of said engaging levers and one of said holding levers out of contact with one of said ratchet wheels to allow said spring means to rotate said first shaft.

3. A combination according to claim 2, in which the cam elements are 180* out of phase with respect to each other to provide a different amount of movement to said holding levers when rotated.

4. A combination according to claim 2, in which a first gear is mounted on said first shaft, a fourth shaft is spaced from said first shaft and has said first spring means mounted thereon to be wound when said fourth shaft is rotated, a second gear is mounted on said fourth shaft to intermesh with said first gear, and manual means is operable to rotate said fourth shaft thereby rotating said first shaft and associated roller means and simultaneously winding up said spring means.

10. A combination according to claim 9, in which a release lever is provided, each release lever extending partly outside of said frame with the remainder thereof extending within said frame to pivot on said second shaft, said release lever including opposing pins on either side thereof respectively engageable in said slots of said holding levers.