US1351993A - Typewriting-machine - Google Patents

Description

Mfnessex L. S. BURRIDGE, DECD. r. 0. sunmnes, EXECUTOR. TYPEWRITING MACHINE.

APPLICATION FILED DEC.3,1917.

Patented Sept. 7, 1920.

2 SHEETSSHEET l- L. S. BURRIDGE, DECD. F. 0. BURRIDGE. sxzcuroa. TYPEWRITING MACHINE.

APPLICATION FILED DEC. 3, 1917.

PatentedSept. 7, 1920.

2 SHEETS-SHEET 2.

l Vhnesses:

' movement by a s ring which counteracts the a UNITED STATES PATENT OFFICE.

LEE s. BURRIDGE, DECEASED, LATE or NEW YORK, N. Y., BY rEANcis -o. BURRIDGE,

EXEGU'IOR, or NEW YORK, N. Y., AssIeNoE, BY MESNE ASSIGNMENTS, TO UNDER- woon TYPEWBITEB COMPANY, or NEW YORK, N. Y., A CORPORATION or DELA- ARE.

TYPEWRITING-MACHINE.

Specification of Letters Patent.

Patented Sept. 7, 1920.-

Original application filed September 27, 1915, Serial No. 52,594. Divided and this application filed Decemher 3. 1917. Serial No. 205.109.

March 11, 1919).

An object of this invention is to provide a simple and positive back-space mechanism which may be economically manufactured and easily assembled,

In the type of machine illustrated, the platen carriage is mounted upon a frame which is shiftable up and down to various positions for permitting the printing of different case-types. .This shiftable frame comprises front and back sheet-metal plates. An escapement wheel, mounted between these front and rear plates, is controlled by fixed and loose dogs. These dogs are alternately shifted by the depression of the-keys of the machine into and out of cooperative relation with the escapement wheel to permit the letter-feed movements of the typewriter carriage under the influence of a propelling spring. When a key is depressed, the loose dog, which normal y engages one of the teeth of the escapement wheel, is-

withdrawn therefrom and moves under the influence of a spring, connected to said dog, into a position in which'it will be engaged by the next succeeding tooth when returned to the esca ement wheel. Before the loose dog'is free from the escapement wheel the fixed dog engages and temporaril holds said wheel. he loose dog is limite in this actions of the ot er spring connected to the do when the dog reaches a proper position toie engaged by the next sucoeedin tooth.

In the present invention, a bat: -space pawl, controlled by a back-space key at the keyboard of the machine, directly engages.

the escapement wheel'to move the same in a reverse direction, and the escapement wheel,

- being positively geared to the carriage,

cause the escapement Wheel has been prevented from rotating in reverse direction by the escapement dogs. Therefore, the backspace mechanism could not operate upon the carriage through the escapement wheel.

In the present invention, however, it is possible to back-space the carriage by rotating the escapement wheel in reverse direction, because of the fact that the escapement dogs permit the backward rotation of the escapement wheel, and therefore, the escapement wheel can be positivel geared to the typewriter carriage. It wil be seen that this arrangement of back-spacing the carriage, through; the escapement wheel, is verysimple and makes it unnecessary to provide numerous additional parts.

The back-space pawl ma be pivotally mounted upon an arm which has a swingmg movement about the axis of the escapement wheel. The back-space key may be pivotally mounted on a bracket secured to the main frame of the machine and have a P01111011 engaging an arm of a bell-crank, which is also mounted on the main frame and which has a link connection to the arm carrying the back-space pawl. In order that the depression of the back-space key may impart a longitudinal motion to the pawl-carrying arm, the axis of the bellcrank is arranged at substantially right angles to the axis of the backspace key. The bell-crank is preferably arranged at a considerable distance from the pawl-carrying arm, so as to permit the case-shifting movements of the latter, which is mounted on the shiftable frame, without interfering with the operation of the back-space mechanismwhile the frame is in any case-position.

The back-space pawl is normally held out of engagement with the escapement wheel by engagement of an arm carried by said pawl with a fixed stop, arranged so that a spring connected to the pawl moves the capement wheel, at the very beginning of the downward movement of the back-space key. The continued movement of the backspace key causes the pawl to drive the escapement Wheel back a distance equivalent to two letter-space movements of the carriage, which allows one tooth of the escapement wheel to pass the loose dog and move to position to engage the loose dog when the back-space key is released. This "causes the carriage to be moved back two letter-spaces and when released to be free to move under the carriage-spring influence one letterspace to proper position.

If the operator desires to insert a character at a place two letter-spaces back from that occupied by the typewriter carriage, the back-space key is depressed and kept depressed by the finger while the omitted character is being printed. However, when the operator desires to reset the carriage only one letter-space distance, the back-space key is fully depressed and then released before the type-key is operated.

Other features and advantages will hereinafter appear.

In the accompanying drawings,

Figure 1 is a side elevation, showing the platen, the platen-carriage and the platencarriage-shift-frame.

Fig. 2 is a sectional side elevation, showing the escapement mechanism.

Fig. 3 is a rear elevation, showing the escapement mechanism and the back-space mechanism.

Fig. 4 is a sectional side elevation, showing the escapement yvheel and the mounting for the back-space pawl.

Fig. 5 is a front elevation, showing the escapement mechanism, the back-space-pawl and-the connections from the back-spacepawl to the back-space-key.

Type-bars 10 swing upwardly and rearwardly against the front face of a platen 11, at the depression of keys 12 mounted on key-levers 13. The platen 11 is mounted on an axle 14 rotatably mounted in side plates 15, forming part of a typewriter carriage 16;.said carriage also comprises transverse bars 17 serving as rails for ball-bearings 18, upon' which the carriage rides in letter-feed and returndirections. The ballbearings are confined between the rails 17 and forward and rearward plates 19 and 20 which form part of a frame 21. The

frame 21, which also comprises side plates 22, is suitably guided and shiftable substantially vertically for the purpose of moving the platen to various case-printing positions.

The typewriter carriage 16 normally tends to move in letter-feeding direction, under the influence of a spring drum 23 connected by a cord or tape 24 to the typewriter carriage. The letter-feed movement of the typewriter carriage is controlled by an escapement mechanism which comprises an escapement wheel 25 and also a pinion 26, secured thereto, engaging with a rack 27 carried by the carriage. The escapement wheel is mounted to rotate on a pin 28 which is removably mounted in bushings 29 and 30, secured to the front plate 19 and the: rear plate 20, respectively. The pin 28 is secured to a plate 31 which is held in place in the machine by being secured to the rear plate 20 by a screw 32. The escapement wheel 25 is confined on the pin 28 between the bushings 29 and 30. The escapement wheel 25 is normally prevented from rotating, under the influence of the carriagespring 23, by an escapement dog 33 which engages with one of the teeth 34 of the escapement wheel. The dog 33 is pivotally mounted at 35 upon a plate 36, and has its movement in one direction limited by a stop-pin 37 secured to the plate 36.

fore. the escapement dog 33 is normally held against the stop-pin 37. The plate 36 is mounted for rocking movement on trunnions 38 which extend through ears 39 in a bracket 40 secured to the rear plate 20. The rocker plate 36 is provided with connections to a universal bar 41 arranged directly beneath, and operated by, the keylevers 13. These connections comprise a floatingly-mounted draw-bar 42 engaging the rocker plate 36 which is operated by an arm 43 carried by a rock-shaft 44 having arms 45 connected by links 46 to the universal bar 41.

When the key-lever 13 is depressed and the rocker plate is operated, the loose-dog 33 is moved out of engagement with the tooth 34v of the escapement wheel, and a fixed dog 47 is'moved into engagement with said wheel, to hold the same temporarily against movement. Thus freed from the escapement wheel, the loose dog 33 is moved up toward the next tooth on the escapement wheel by a spring 48, connected to an arm 49 extending rearwardly from said dog, into theposition shown in dot-and-dash lines in Fig. 3. In this position the dog 33 is located opposite the next tooth. When the rocker plate is returned to normal position by its spring 50 (see Fig. 2), the fixed dog 47 is moved out of engagement with the escapement wheel, and the loose dog 33 is moved into position to be engaged by the next tooth on the escapement wheel. After being released by the fixed dog 47, the escapement wheel rotates under the carriagespring influence until the said next tooth 34 strikes the dog 33 and moves the same against the tension of its spring 48 until the lower edge of the dog is arrested by the stop 37 on the rocker plate 36. This causes the carriage to move one space in letter-feed direction. The loose dog 33 is limited in its upward movement to the dot-and-dash line position, shown in Fig. 3, by a spring 51-. This spring 51 tends to oppose the action of the spring 48,"'when the loose dog has moved to the pro r yieldingly hold said 0g.

key 52 on a lever 53, pivoted at 54 to a bracket 55 on a cross-piece56 in the main frame. The lever 53, when depressed at its forward end, engages at its rearward-end and moves an arm 57 of a bell-crank '58 pivoted at'59 on a bracket 60, also on the main frame. The bell-crank 58 is held in normal position by a spring 61. The other arm 62 of the bell-crank 58 is connected by a link 63 to an arm 64, whichis mounted to rotate about the axis of the escapement wheel 25. The arm 64 has 'pivotally-connectedthereto at 65 a drive pawl 66 having a nose 67 arrangedto en age the teeth 34 of the escapement wheel. he drive pawl 66 is preferably made of sheet-metal and has a bent-off portion which forms the nose 67. The pawl normally tends to move into engagement with the escapement wheel, under the influence of a spring 68 having one end connected to an arm 69 on the pawl-carrying lever, and its other end connected to a bentoff portion 70 on an arm 71 formed integral with the drive pawl 66. The pawl 66 is normally held out of engagement with the escapement teeth, against the tension of the.

spring 68 by a projec tion or guard 72 with which the bent-off portion70 of the pawl engages.

At the first portion of the downward movement of the back-space-key 52, the link 63 is moved to the left, as seen in Fig. 5, to rock the pawl-carrying arm 64 suflicient to permit the bent-ofi' portion 7 O of the pawl 66 to move away from the guard 72 under the influence of its spring 68, so as to bring the nose 67 of the pawl into engagement with one of the teeth 34 of the escapement wheel. The continued downward movement of the back-space key causes the pawl-carrying arm- 64 to drive the pawl, and the pawl, in turn, to drive the escapement wheel to back-space the typewriter carriage.

As the-escapement wheel is moved in re verse or anti-letter-feed direction, under the control of the back-space pawl 66, the tooth 34 of the escapement wheel, which is located beneath the escapement dog 33, as seen in Fig. 3, is moved upwardly. This causes said tooth to cam the loose-dog 33 upwardly against the tension of the dog-controllingspring 51, until the dog has been cammed to l position, and'thus writer carriage to be moved back two letter- The back-space mechanism comprises a ment wheel may pass the same, and in which spaces. This movement of two letter-spaces permits the tooth of the escapement wheel to engage and move the loose escapement dog and move past said dog sufficiently to permit the dog to moved by its spring into a position shown in Fig. 3, in dot-anddas'h lines. In this position the loose escapement dog will be engaged by the tooth ofthe'f'escapement wheel and moved under the influence of the carriage, when the backspace key is released, until the dog strikes its fixed stop 37, which will arrest the carriage at one letter-space distance from the point at'which the back-spacing operation was commenced. Y

The back-space key when released is returned to normal position by the spring 61. This spring also returns the pawl-carrying arm 64 with the pawl 66. The teeth 34 of the escapement wheel are so shaped as to cause the nose 67 of the pawl 66 to be cammed out and pass said teeth during the return movement of the pawl. The pawl is finally held out of engagement with the teeth of the escapement wheel by the guard 72,

against which the bent-portion 70 on the pawl 66 ;strikes-.-- This causes the pawl to swing about its pivot "65, so as to withdraw the nose from the teeth ofthe escapement wheel against the tensionof the spring 68. To permit the back-space key to operate the pawl-carrying arm in all case-positions of the platen frame on which the pawl-cartance between the bell-crank and the pawlcarrying arm is such that the variation of the angular position of the link in no way affects the operation of the back-space mechanism.

For convenience in assembling the device, the pawl-carrying'arm 64 is pivotally mounted upon the bushing 30, which, with the bushing 29, serves as a support for the pin 28 on which the escapement wheel is mounted. In assembling the device, the pawl- .earrying arm may be slipped upon the bushing 30 before the'escapement wheel is placed in position. If it is desired to remove the pawl-carrying arm for the purpose of re-' pairs, the pin 28 may be withdrawn from the bushings 29 and 30, and the escapement wheel temporarily removed to permit the withdrawal of the pawl-carrying arm 64 from the bushing 30.

If the operator desires to print a character two letter-spaces back from the position occupied by the carriage, the back-space key is depressed and held depressed during the printing operation; for it will be remembered that the back-space key, when depressed, moves the typewriter carriage back two spaces, so that, when released, the carriage will be arrested at the proper place by the escapement dog. Therefore, if the back-space key is maintained depressed, the carriage will be located two letter-spaces from the position previously occupied.

Variations may be resorted to within the scope of the invention, and portions of the improvements may be used without others.

Having thus described the invention, the claims are:

1. In a typewriting machine, in combination, a platen-carriage, letter-spacing mechanism therefor, including an escapement wheel and mechanism cooperating therewith to control its movements in normal letterfeeding direction, said wheel and controlling mechanism being so related as to permit a back-spacing rotation of said wheel in the reverse direction, and back-spacing mechanism for said wheel, comprising a back-spacing pawl, a' movably mounted pawl-carrier therefor, means normally tending to move said pawl relatively-to said carrier to a position such as to engage a tooth of said escapement wheel, a stop fixedly mounted on said carriage, an abutment on said pawl, normally held in engagement with said stop, and preventing'movement of said pawl to its tooth-engaging relation, and means for moving said carrier so as to separate said abutment from said stop, to permit said pawl to be moved into tooth-engaging relation with said escapement wheel, and rotate said wheel in a reverse direction, to an extent such as to bring a different tooth of said escapement wheel into position to be engaged and held by said controlling mechanism.

2. In a typewriting machine, the combination with' a platen, ofmeans including a carriage for feeding the platen in letterfeed direction, and means for effecting a step-by-step movement of the platen carriage in the opposite direction, comprising a toothed member connected to the typewriter carriage, a pawl adapted to engage said toothed member, means including a movable pawl-carrier for causing the pawl to engage and move said toothed member, said carriage being shiftable bodily up and down together with said carrier, a bell-crank to which said carrier is directly connected by a single link, said bell-crank beingmounted on the stationary framework, and a key-lever arranged to directly engage and rock the bell-crank.

3. In a typewriting machine, the combination with a main frame, of a platen frame shiftable bodily between case positions on the main frame, a platen, means on the platen frame for feeding the platen in letter-feeddirection, and mechanism for effecting a step-by-step movement of the platen in the opposite direction, comprising a toothed wheel on the shiftable platen frame, a pawl adapted to engage said wheel, a movable carrier for said pawl, said pawl and carrier being shiftable together with said platen frame, and means for causing the pawl to engage and move the wheel, said means including a link directly connected to said carrier, and means on the stationary main frame for directly engaging and actuating said link, said link being so arranged as to vibrate to permit the case-shift movements of said pawl and carrier with said platen frame, without interfering with the operation of said pawl in all case positions of the platen frame,

4. In a typewriting machine, in combination, a frame, a platen-carriage shiftable to different case positions relative to said frame, letter-spacing mechanism therefor, including an escapement wheel and mechanism cooperating therewith to control its movements in normal letter-feeding direction, said wheel and controlling mechanism being mounted on said shiftable platen-carriage, and so related as to permit a rotation of said wheel in the reverse direction, and back-spacing mechanism for said wheel, comprising aback-spacing pawl, a movably mounted pawl-carrier therefor, said carrier being mounted on said shiftable platen-carriage, and means for causing said pawl to engage a tooth ofsaid wheel to impart a reverse rotation thereto, said pawl-operating means including a relatively long link extending transversely of the machine, said link being connected at one end to said pawlcarrier, and 1 a key-controlled operating mechanism mounted on said frame and connected directly to the other end of said link, so that the movement of said pawl and carrier fromone case position to another with said platen-carriage may cause a swinging movement to be imparted to said link, While preserving the cooperative relation between said key-controlled operating mechanism and the back-spacing pawl and carrier.

FRANCIS O. BURRIDGE, Executor 0f the last will and testament of Lee S. Bwm'dge, deceased.

' Witnesses:

CHARLES W. HOWELL, ARTHUR A. JOHNSON.

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