US1713086A - Typewriting machine - Google Patents

Description

May 14, 1929. A. G. KUPETZ TYPEWRITING MACIjINE Filed Aug. 25. 1925 i I l Patented May 14, 192.9.

ADOLYPH G. KUPETZ, 035 NEW YORK, N. Y., A.

SFSIGNOR TO UNDERWUOID ELLIOTT FISHER COMPANY, OF NEW YGRK, N. Y., A CORPORATION OF DELAWARE.

TYPEWRITING MACHINE.

Application filed August 25, 1925. Serial No. 52,271.

This invention relates to line-spacing mechanism for typewriting machines, and has particular reference to the provision of the prevention of overthrow of the platen.

The line-spacing mechanism in standard llnderwood typewriting machines includes a ratchet rotatable with the platen and operated by a pawl pivoted upon a slide on the platen-frame. The slide is actuated by a line space lever, and is limited in its linespacing movei'nent by the engagement of the pawl with an overthrow-prevention stop. Such devices are subjected to rather hard usage, particularly in that type of machine in whiclrthe carriage-return and the line spacing of the. platen are accomplished by the use of an electric motor. lilxcessive strain on the over throwprevention stop soon renders the stop inetlective to accurately determine a line-space distance, and there after causes the platen to overthrow its norreal line'space stop position.

l he present invention aims to relieve all strain, incident to a violent movement of the line-spacing lever, from the line-space pawl and the line-space wheel. This is done by providing that the line-space slide may be arrested at the end of a line-spacing stroke through abutmentwith the carriage-frame, while a second or auxiliary stop becomes operative independently of the first stop, to prevent overthrow of the platen beyond the line-spaced position determined by the slide, Hence the stress developed. through the coaction of the line-space pawl and line space wheel is due to the momentum of the line spaced platen, and not from the violent manipulation of the line-space lever and the momentum of the hand and arm of the operater, or of other driving means.

These objects are accomplished by the provision of a permanent stop mounted on the platendirame and engageable by the linespace slide, whereby movement of the slide will be arrested at the end of its linespacing movement and without conveying any stress to the overthiowprevention stop. In this manner, the overthrow-prevention stop is relieved of the shock incident to a sudden or violent manipulation of the line-spacing lever.

Other features and advantages will here of a typewriting invention. t

Figure 2 is a fragmentary front elevation with parts in. section. 1

Figure 3 is a detailfront elevation of one end oi": the platen-frame.

F' me i is a sectional View on the line l l; of Figure 2.

Figure Tris aview similar to Figure 1, showing the linespace slide moved inwardly to the limit of its possible movement.

, Figure 6 is a fragmentary top plan view of the device.

A platen 10 is fixed upon a shaft 11 lior rotation in the ends 12 of a platendirame supported by the usual carriage 13. A trans versely movable slide 14E is mounted in one end of the platendrame, and has pivoted, as at 15, a pawl 16 which engages a rah-hot 17 rotatable with the platen 10. The ratchet 17 is engaged by the usual roller detent 17 to maintain the platen in proper s aced position when the pawl becomes disengaged from the ratchet. Carried by a rearward extension 18 of the slide 14 is a pin 19, which is loosely engaged by an arm 20 01 a vertical rock-shaft 21. The shaft 21 is supported at its bottom end in a bracket 22 and connected to the usual power-driven carriage return and line-spacing mechanism, of H. L. Pitman, patented April 13, 1926, No. 1,580,326, and designated generally by the character 23. A coil spring 24.- has one of its ends semired to the extension 18 ot the slide 14, while its other end is attached to one 01. the end members of the platenl'rame, whereby the slide 14: and its associated parts will maintain a normal. position, as illustrated-in Figure 1.

A nose member 25, carried by the pawl 16 and having an angularly-disposed rear edge 26, co-operates with an overthrow-prevention stop 27 to prevent the ratchet and platen from running beyond their proper positions after the line-space slide 14 has been shifted. The stop member 27 is placed immediately beyond the rearward limit of the edge 26, so that it will not actually be engaged except in the event that the platen and ratchet start to overthrow.

In order to limit the rearward movement of the slide 14, and thus relieve the overthrow prevention stop of shock, incident to machine embodying the the line-spacing operation, the forward end of the slide is offset as at 28. A stop memmanner.

ber 29 is mounted upon the carriage 13 in the path of movementof th offset 28. This stop member is here shown as being mounted with the carriage-shift lock 30, but itmay, of'course, be attached in any other suitable The forward end of the platenframe 12 may have a suitable reinforcement as at31 to increase the'meehanical strength of these parts.

The slide 14 may be actuated by a line spacing lever 32, which may be manually operated orotherwise, and, when the offset 28 abuts the stop member 29, further rearward movement is prevented. In the event that the lever 32 is'shifted violently, so that the platen l0 and ratchet l7 tend to overrun,

the engaging tooth of the ratchetwill, by a cam action, raise the pawl 16 about its pivot 15, whereupon the inclined edge 26 of the pawl nose will contact with theoverthrowprevention stop 27 and prevent 'further upand pawl is arrested at the line-spaced position by a positive stop on the frame; that the line-space pawl, per se, loses control of the platen and line-space wheel beyond the l shock incident to arresting the line-space slide; and that the other stop checks the overthrow of the platen without excessive strain upon the eoacting parts.

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

Having thus described my invention, I claim:

In a typewriting machine, the combination with a rotatable platen and a line-space wheel, of a line-space slide provided with an integral stop thereon, a mani1ally-o1 )erable line-space lever adapted to engage said stop to move said slide, said stop also serving in operated position as a limit stop for said slide, a pawl pivoted on said slide and engageable with the line-space wheel to retate the platen, and means independent of said stop to limit the rotary movement of the platen beyond the line-space position.

ADOLPH Gr. KUPETZ.

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