US3651913A

US3651913A - Type bar head for typewriters having an interchangeable type block

Info

Publication number: US3651913A
Application number: US843571A
Authority: US
Inventors: Walter Albrile
Original assignee: Ing C Olivetti and C SpA
Current assignee: Telecom Italia SpA
Priority date: 1968-07-22
Filing date: 1969-07-22
Publication date: 1972-03-28
Anticipated expiration: 1989-03-28
Also published as: DE1935683A1; FR1598527A; GB1264706A; CH500842A

Abstract

A type bar head for typewriters is provided with an interchangeable typeblock formed in a single piece of flexible plastic material covered with a deposit of metal. The type block is provided with a pair of flanges having a pair of wedge shaped projections engaging two chamfered edges of the type bar to block the type block in a direction perpendicular to the printing surface and with a resilient tongue between the flanges to lock the type block in a direction parallel to the printing surface.

Description

United States Patent Albrile [451 Mar. 28, 1972 [54] TYPE BAR HEAD FOR TYPEWRITERS 2,862,592 12/1958 Redmond ..197/36 HAVING AN INTERCHANGEABLE 2,975,881 3/1961 Delponte et a1. ..l97/36 TYPE BLOCK 3,101,141 8/1963 Canny ....l97/36 3,308,916 3/1967 Canny et al..... ....l97/36 [72] Inventor: Walter Albrile, Tonno, Italy 3,381,788 5/1968 Meisner et al. ....197/36 3 432 018 3/1969 Watanabe et a1.. ..197/36 73 A l tt ssignee ngo C Olive 1 & C S p A Tormo, Italy 3,434,867 3/1969 Rousselot 197/52 X [22] Filed: July 22, 1969 FOREIGN PATENTS OR APPLICATIONS [21] Appl. No.: 843,571

9,836 11/1910 Great Britain ....197/36 955,111 1 1950 F ..I97 36 [30] Foreign Application Priority Data fame July 22, 1968 Italy ..s2544 A/68 Primary Examiner-Edgar Burr Attorney-Irons, Birch, Swindler, McKie & Beckett [52] U.S. Cl ..197/36 51 Int. Cl. ..B4lj1/02 ABSTRACT [58] Field ofSearch ..197/36, 52 A type bar head for typewriters is provided with an terchangeable typeblock formed in a single piece of flexible [56] References cued plastic material covered with a deposit of metal. The type UNITED STATES PATENTS block is provided with a pair of flanges having a pair of wedge shaped pl'OjECllOl'lS engaging two chamfered edges of the type BUSZ 1 bar to block the type block in a direction perpendicular to the 1,189,522 7/ 1916 Anderson 197/36 printing surface and with a resilient tongue between the 1,206,972 12/1916 Anderson ..197/36 fl to lock the type block in a direction parallel to the 1,357,573 11/1920 Lee ..l97/36 priming Surface 2,171,470 8/1939 Munoz.... .....197/36 2,446,360 8/1948 Clark 197/36 X 3 Claims, 3 Drawing Figures 1 ll 1 7 u 21 8 Ll' 1 2'5 9 F" I n1 v11 u 11 26- 23 I I' 19 PATENTEDHARZB I972 3.651.913

INVENTOR. WALTER ALBRI LE TYPE BAR HEAD FOR TYPEWRITERS HAVING AN INTERCHANGEABLE TYPE BLOCK BACKGROUND OF THE INVENTION 1. Field of the invention The present invention relates to an interchangeable type block for the type bars of a type writing or other such machine in which type bars cooperate with a platen to effect printing. The type block is formed with a slot adapted to he slipped over the head of the type bar.

2. Description of the prior art Various type bars with interchangeable types are known. In one known type bar, the head of the bar is in the form of a resilient fork, so as to lock the type slipped on to it. Exchange of the type is rather difficult, however, since it is necessary to bend the two arms of the fork while the type is slipped off.

In another known type bar, the type is formed by a metal plate bent in the shape of a U. The plate is provided with stamped projections for locking it on the head of the type bar. The type is excessively cumbersome in width, however, so that the type plate must be suitably slotted.

SUMMARY OF THE INVENTION The object of the present invention is to provide a type block which is easily interchangeable, of low cost and has the minimum width dimension. According to the invention, the block is formed with a slot open on the side remote from the type or types and having projections or recesses in the slot which provide surfaces adapted, when the block is mounted on the head of the type bar, to cooperate with complementary surfaces of the head to resist movement of the block in at least two substantially perpendicular directions.

The invention will be described in more detail, by way of example, with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a median section of a type bar with an exchangeable type block embodying the invention;

FIG. 2 is a section on the line II II of FIG. 1;

FIG. 3 is an exploded perspective view of the type bar.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, the reference 5 indicates the terminal portion of a type bar of a type writing machine, which is provided with the usual projection 6 adapted to engage the type guide, which is not shown in the drawing. The type bar 5 is provided with a head 7 on which there is mounted a type block indicated generally by the reference 8. On ,a substantially plane front surface 9 the block 8 carries two

types

10 and 11.

The block 8 is provided with a slot 12 (FIG. 2) which is open on the side remote from the types and adapted to be slipped over the head 7 of the type bar 5, the slot being defined by two lateral flanges l3 and 14 of very slender thickness which may range between 0.4 and 0.8 mm. The block 8 is provided at the top with a second resilient tongue 15 (FIG. 1) separated from the

flanges

13 and 14 by a slot 16 and adapted to cooperate with a shaped edge 17 of the head 7 of the type bar 5 and with a top edge 27 of each of the flanges l3 and 14 (FIG. 3). That is, edge 17 provides a fulcrum about which tongue or lever 15 may pivot to lift the slot in the block 8 out of engagement with the type bar.

The type bar 5 is provided with a first shoulder 18 adapted to act as an abutment for a bottom edge 19 of the block 8 to locate the block in a direction parallel to the front surface 9 and, therefore, to the writing surface of the

types

10 and 11. That is, abutment of edge 19 with shoulder 18 prevents further downward longitudinal motion of type block 8.

A first resilient tongue 20 extends from the base of the slot 12 perpendicularly to the surface 9. The tongue 20 is adapted to cooperate with another shoulder 21 of the type bar 5 in such manner as to retain the block 8 in the direction parallel to the surface 9, i.e., further upward longitudinal movement of the block is prevented by the abutment of these two surfaces. Thus, the

shoulders

18 and 21, along with edge 19 and tongue 20, respectively, serve to prevent longitudinal motion of the block, when it is in place on the type bar head.

The head 7 of the type bar 5 is moreover provided with two edges 22 formed from the rearwardly facing edge of the type bar and perpendicular to the two

shoulders

18 and 21, these two edges being chamfered at 45. The block 8, in turn, is provided in its slot 12 with two wedge-shaped lugs 23 projecting from each of the

flanges

13 and 14. Each lug 23 has a face 24 inclined at 45 and adapted to cooperate with one of the chamfered edges 22 of the head 7 of the type bar 5. The cooperation of the lugs with the chamfered edges serves to prevent rearward lateral motion perpendicular to the writing surface. Moreover, in the slot 12 there are provided two upper projections 25 and two lower projections 26 adapted to embrace the head 7 of type bar 5 and to be urged resiliently against the lateral surface of the head itself by virtue of bending of the block to prevent forward lateral motion. Thus, motion by the type block in a direction perpendicular to the writing surface is prevented.

The type block 8 is preferably formed in a single piece and is preferably made of high-strength plastics material, for example polyacetal resin known by the Trade Mark Hostafom" which is produced by the German company Hoechst. The block 8 formed of this material is metallized by means of a first chemical deposit of copper, a following electrolytic deposit of copper, an electrolytic depost of nickel and, finally, an electrolytic deposit of chromium, which gives the outer surface the hardness necessary for clear writing and for long life.

To remove the block 8 from the head 7, the tongue 15 is pressed with a finger so as to urge it first of all against the edge 17. By continuing to exert pressure, the tongue 15 bears against the edges 27 of the flanges l3 and 14, thus forcing the block 8 outwards and disengaging the tongue 20 from the shoulder 2 1.

To re-mount the block 8 on the head 7, the block 8 is forced with two fingers, acting simultaneously on the tongue 15 and on the surface 9, until the tongue 20 is inserted below the shoulder 21 and the lugs 23 snap behind the chamfered edges 22.

What I claim is:

1. In a type bar head for typewriters and the like constituted by a type bar and a removable type block wherein the type block is a channel-shaped member formed from a type surface member and a pair of relatively flexible flanges extending perpendicularly from opposite ends of said type surface defining a substantially U-shaped slot opening on the side of said type block remote from said type surface, said slot being constructed to receive said type bar, the improvement comprismg:

a surface on said type bar and an opposed surface on said type block, said surface and said opposed surface being positioned on said type bar and said type block, respectively, as to abut each other when said type bar is engaged in said slot, the abutment of said surface and said opposed surface preventing motion of said type block relative to said type bar in a first direction parallel to the plane of said type surface and longitudinally of said type bar,

shoulder means on said type bar and first flexible tongue means extending from said type block inwardly of said slot, and perpendicularly to the plane of said type surface, said shoulder means and said first flexible tongue means being positioned on said type bar and said type block, respectively, as to abut each other when said type bar is engaged in said slot, the abutment of said shoulder means and said tongue means preventing motion of said type block relative to said type bar in a second direction parallel to the plane of said type surface and longitudinally of said type bar,

a pair of outwardly facing chamfered surfaces formed on edges of a side of said type bar remote from said type surface and longitudinally extending parallel to said type surface,

a pair of opposed projections integral with said flange members extending inwardly of said slot and having inclined surfaces arranged for cooperating with said chamfered surfaces so that said chamfered surfaces and said inclined surfaces are in abutment when said type bar is engaged in said slot, the abutment of said chamfered surfaces and said inclined surfaces preventing motion of said type block relative to said type bar in a direction perpendicular to said type surface,

shaped edge means formed on said type bar and forming a fulcrum-like member and second flexible tongue rneans mounted on said type block in a position as to be manually depressable against said block is formed in a single piece of flexible plastics material covered with a deposit of metal.

3. A type bar head according to claim 1, having another pair of projections in the interior of said slot adapted to be forced by bending against the lateral surfaces of the head of the type bar.

Claims

1. In a type bar head for typewriters and the like constituted by a type bar and a removable type block wherein the type block is a channel-shaped member formed from a type surface member and a pair of relatively flexible flanges extending perpendicularly from opposite ends of said type surface defining a substantially U-shaped slot opening on the side of said type blOck remote from said type surface, said slot being constructed to receive said type bar, the improvement comprising: a surface on said type bar and an opposed surface on said type block, said surface and said opposed surface being positioned on said type bar and said type block, respectively, as to abut each other when said type bar is engaged in said slot, the abutment of said surface and said opposed surface preventing motion of said type block relative to said type bar in a first direction parallel to the plane of said type surface and longitudinally of said type bar, shoulder means on said type bar and first flexible tongue means extending from said type block inwardly of said slot, and perpendicularly to the plane of said type surface, said shoulder means and said first flexible tongue means being positioned on said type bar and said type block, respectively, as to abut each other when said type bar is engaged in said slot, the abutment of said shoulder means and said tongue means preventing motion of said type block relative to said type bar in a second direction parallel to the plane of said type surface and longitudinally of said type bar, a pair of outwardly facing chamfered surfaces formed on edges of a side of said type bar remote from said type surface and longitudinally extending parallel to said type surface, a pair of opposed projections integral with said flange members extending inwardly of said slot and having inclined surfaces arranged for cooperating with said chamfered surfaces so that said chamfered surfaces and said inclined surfaces are in abutment when said type bar is engaged in said slot, the abutment of said chamfered surfaces and said inclined surfaces preventing motion of said type block relative to said type bar in a direction perpendicular to said type surface, shaped edge means formed on said type bar and forming a fulcrumlike member and second flexible tongue means mounted on said type block in a position as to be manually depressable against said shaped edge means and then against another portion of said type block, said second tongue means being caused to pivot about said shaped edge means lifting said slot out of engagement with said type bar thereby facilitating removal of said type block from said type bar.

2. A type bar head according to claim 1, wherein said type block is formed in a single piece of flexible plastics material covered with a deposit of metal.