US 2094550 A
Description (OCR text may contain errors)
Sept. 28, 1937. JP. OHALLORAN 2,094,550
' TYPEWRITER Filed June 1, 1937 Patented Sept. 28, 1937 TYPEWRITER Joseph Patrick OHalloran, London, England, assignor to Okopa Carbon Paper Eliminator Limited, London, England Application June 1, 1937, Serial No. 145,863 In Great Britain May 9, 1936 3 Claims.
This invention relates to typewriters, calculating machines and the like. In such machines there is an inherent difficulty, in that when the paper is inserted and the typing is done there is in many cases a slight impression or mark under the letters actually typed. This may be due to the platen being too large, or the paper not fitting snugly round the platen, thus causing a bulge of paper at the point of type. This difficulty is in nearly all cases very apparent when more than two or three copies are being made, and in such cases the first paper receiving the actual impact of the type has a dirty appearance.
0n the majority of machines described above, there is, attached on the front of the platen, a
line gauge, with the centre piece cut out, the cut-out permitting of the passage of the type bar as it moves forward to strike the paper. The type bar generally carries two characters, one above the other, and the usual practice is for the upper character to represent a capital and the lower, a small letter. When typing capitals there is a tendency for the lower character to mark the paper beneath the capital owing to the upper part of the small character pushing the lower part of the ribbon against the paper, thus causing the typed matter topresent an unpleasing appearance.
With a View to overcoming this disadvantage, the line gauge is fitted, according to the invention, with a mask attached to the back of the line gauge and extending across the lower portion of the cut-out therein, so as tointercept the portion of the type barbelow the character to be typed and prevent it from marking the paper.
The mask may be of any convenient material, e. g. metal. It may beformed as a unit with the line gauge ormay be constructed as a separate element attached to the backof the line gauge by welding, riveting or in any other convenient way. Being located between the ink ribbon and the paper the mask will serve to protect the paper against receiving undesired impressions. Its height must of coursebe sufficient to intercept the impression from the lower character on the type bar when the upper character is being typed, and so prevent any marking of the paper.
The invention will now be described in'greater detail with reference to the accompanying draw ing, in which:-
Fig 1 i a perspective view of a conventional form of typewriter fitted with the device accord: ing to the invention;
Fig. 2 shows the line gauge and mask detached from the typewriter, and
Fig. 3 is a vertical section through the platen of the typewriter.
It will be understood that the invention is applicable not only to typewriters but also to calculating and like machines in which an imprint is made through a line gauge by means of type bars and the expression typewriter as used in the appended claims is intended to have this broader significance.
cured by nut and bolt connections I9 to brackets.
(not shown) secured to the framework of the machine. The line gauge is provided with a cut-out 2% to permit of the passage of the type bars as they move forward to type on the paper.
In order to prevent the portion of the typebar underneath the character being typed from marking the paper, a mask 2| is fitted to the rear of the line gauge. This consists of a metal strip, one end of which has a projecting portion 22 which is bent over to embrace the line gauge and serves for the attachment of the mask to the line gauge. This attachment is effected by means of the left hand nut and bolt connection IS. The other end of the mask is spaced slightly from the line gauge as illustrated. The mask, therefore, does not impede the forward movement of the type bar into printing position but it serves to protect the portion of the paper below the printing line and prevent it from being marked by the type bar.
What I claim as my invention and desire to secure by Letters Patent is:-
1. In a typewriter having type bars, a platen, an ink ribbon extending in front of the platen,
and a line gauge, disposed between the ribbon and the platen and'having a cut-out to permit of the passage of the type bars through the line gauge into position to type on a paper sheet carried by the platen, the combination with the line gauge of a mask attached to the back of the line gauge and extending across the lower portion of the cut-out therein so as to intercept the portion of the type bar below the character to be typed and prevent it from marking the paper.
2. In a typewriter, the combination as claimed in claim 1, in which the mask consists of a metal strip extending parallel to the line gauge and attached thereto at one end only.