US2021195A - Line-spacer for typewriters - Google Patents

Description

NOV. 19, 1935. MULHARE 2,021,195-

LINE SPACER FOR TYPEWRITERS Original Filed July 27, 1922 Patented Nov. 19, 1935 UNITED STATES PATENT OFFICE Refiled for abandoned application Serial No. 577,798, July 27, 1922. This application July 7,

1934, Serial No. 734,188

2 Claims.

The present invention relates to the means whereby the platen of a typewriter is turned at the end of a line for the purpose of feeding the paper forward before beginning a new line, and

5 provides an improvement, the principal advantages of which are lightness and economy of parts, simplicity of construction affording easy assembling and perfect accessibility, combined with maximum convenience and certainty of lo operation.

The invention is illustrated in a preferred form in the accompanying drawing, wherein Figure 1 is a plan view of one end of a platen and carriage equipped with the improved line spacer; Figure 2 la is a vertical section on the line 2-2 of Figure 1 Figure 3 is a similar View on a larger scale and on the line 3--3 of Figure l; and Figure 4 is a plan view of the shiftable shield for adjusting th distance between the lines.

20 According to this invention the operation of the line spacer is combined with the act of pushing the carriage back fromQleft to right to bring the beginning of the new line opposite the printing point. This is accomplished by the follow- 25 ing construction.

The usual platen I is carried by a shaft H, which may either be turned manually by means of the handle I 2 or, in the case of normal line spacing, by means of mechanism acting upon the 30 ratchet wheel R3. The spring l4, fixed at one end to the carriage frame has a roller [5 at its free end which presses normally against two successive teeth of the ratchet wheel I3, to steady the platen during printing, as shown in Figure 3.

35 For ordinary line spacing the ratchet I3 is impelled by a pawl I6, pivotally attached at IT to an arm l8, which swings on a horizontal stub shaft I9 carried by the frame of the carriage. A coil spring 20 has one end attached to the pawl H5 40 and the other to a projection 2| on the arm l8, and this spring acts to hold the pawl l6 down upon the ratchet it. A spiral spring 22 on the stub shaft i9 acts to retract the pawl It by swinging the arm it out into the position shown in 45 full lines in the drawing.

Upon a vertical screw pivot 23 there swings a two-armed shift-lever whose shorter arm 24 impinges upon the back of the arm l8, and whose longer arm 25 is provided with a finger piece 26,

50 rising vertically from its outer end. The position of the pivoted arm H3 carrying the pawl l6 and of the shift- lever 24, 25, upon the return movement thereof following therelease of the finger-piece 26, and under the force of spring 22,

55 is limited and determined by an abutment 21 on three positions.

arm 25 of the shift-lever making contact with a stop-pin 28 on the carriage frame.

In returning the carriage to begin a new line, the operator merely presses upon the left hand side of the finger piece 26. The first effect of 5 this pressure is, of. course, to swing the two-armed lever in the horizontal plane, pushing the arm l8 and the pawl l6 forward, until the projection 2i strikes the ratchet l3, as shown in Figure 3. This projection 2| is so shaped and placed as to come down squarely against one of the teeth of the ratchet I3 thereby bringing the platen accurately into printing position and holding it against any tendency to over-run due to momentum, however quickly the pawl may be o-per- I ated.

The mechanism thus far described would always act to turn the platen forward a maximum distance, which would be a distance of three teeth in the form shown, as indicated, in dotted lines in Figure 3. For practical purposes, however, it is desirable that the operator should be able to feed the paper one, two or three spaces forward at will, and the mechanism making this possible is shown clearly in Figures 1, 3 and 4. 26

For this purpose thereis fixed to the end of the carriage a bracket 41 having a cylindrical or arouate shelf 48 extending toward the platen, and there is mounted upon this shelf a shield 69 which fits the surface of the same, as clearly shown in 30 Figure 4. The shield 49 is provided with guide slots 3|], 3|, through which extend the guide pins 32, 33, which screw into the shelf (see Figures 3 and 4).

The convex surface of the shield 49 is furnished with a cylindrical chamber 34, through the top of which extends the adjusting pin 35, having a head 36 conveniently shaped for easy manipulation. A spring 31 is compressed between the top of the chamber 34 and a collar 38 40 on the pin, and this spring presses the pin inward, so that, when this pin is brought opposite one of the openings 39, 4%] or 46, it is forced into the same, and acts to lock the shield in one of Two extreme positions are shown respectively in full and in dotted lines in Figure 3.

The shield 49 has an extension 42 lying concentrically with and just over the ratchet I3,

and when the pawl I6 is in its normal or inactive 50.

position, its point rides on this extension 42.

When the shield 49 is in the position shown in Figures 1, 2 and 3, with the pin 35 in the hole 39, the actuation of the pawl It in the manner already described carries its point immediately 56 over the edgeof the extension 42, so that its engagement with the ratchet I3 is maintained throughout the maximum period, and the platen is moved through a three-tooth space. By shifting the shield 49 so as to bring the pin into the hole 430, engagement of the pawl with the ratchet is delayed, so that the platen is only turned through a two-tooth space. By bringing the pin 35 into the hole 4|, a one-tooth space between lines is produced. It is, of course, clear that the pin 35 can be withdrawn from any hole by pulling outward on the cap or head36.

Various changes may be made in the form-and arrangement of this device without departing from the scope of the invention, which is not limited to the details herein shown and described.

carriage, a platen having a ratchet wheel fixed thereto, -a pawl, means for moving said pawl into engagement with said ratchet-wheel and to thereafter advance it, an arcuate plate extending over said ratchet-wheel between the ratchet Wheel and pawl, an'extension from the frame of said carriage having a portion corresponding to the arcuate portion of saidplate and on which said plate is slidable, and means for shifting the position of said plate to determine the position at which said pawl makes contact with said ratchet-wheel, and thereby the number of teeth said ratchet-wheel is advanced by said pawl.

2. 21 line spacer for typewriters, comprising a carriage, a platen having a ratchet-wheel fixed thereto, a pawl, means for moving said pawl into engagement with said ratchet-wheel and to which said pawl makes contact with said ratchet-wheel, and thereby the number of teeth said ratchet-wheel is advanced by said pawl, and means on said plate arranged to engage said extension for holding said plate in its adjusted positions.

ANDREW MULHARE.

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