US1159645A - Type-bar antifriction-bearing. - Google Patents

Description

A. T. BROWN.

TYPE BAR ANTIFRICTION BEARING.

APPLICATION FILED FELT-1', 1912. 1,159,645. Patented Nov. 9, 191-3.

1 INVEN ATTORNEYS WITNESSES:

TYPE-BAR ANTIFRICTEON-BEARING.

Specification of Letters Patent.

Patented Nov. 9, 1915.

Application filed February 14, 1912. Serial No. 677,578.

To aZl who: it may concern Be it known that I, i inexaicoau T. BROWN, of Syracuse, in the county of Onondaga and State of Few York, have invented a new and useful TypeBar Antifriction-Bearing, of which the following is a specification.

My invention relates to a blank for forming a thin ring-shaped type bar bearing member provided with a peripheral thread at one edge and a hardened conical, or boyeled, ball race surface at its other edge, and

in which the axis of the thread will be coincioent with the axis of the cone, of which said ace surface is a peripheral section or zone.

In describing this invention, reference is had to the accompanying drawing, in which like characters designate corresponding parts in all the views.

Figure 1 is a side elevation o type bar and a bearing embodying my invention. Fig. 2 is a sectional view, partly in elevation, on line fi fl i, Fig. 1. Fig. 3 is aft-agmentary view, partly in section, of a cylindrical bar from which members of my hearing are formed. Fig. sis a cross-sectional view through the bar, shown'in Fig. 3. Fig. 5 is a sectional view of a partially "completed bearing member, tools for operation thereupon being shown in dotted lines. Fig. 6 is a sectional View of the completed bearing member, additional tools being illustrated in dotted lines and diagrammatically. Fig. 7 is an enlarged view of the complete bearing member.

The invention is illustrated in connection with the type bar and supporting segment employed in th well-hnown Smith-Pren'iier typcwriting machine. The type bar is provided at one end with a type block and at its other end with an efve inclosing a set of antifriction balls held between a ball race formed in the supporting segment, and a corresponding race formed by compleinental hearing mci'nbers adjustably supported within the eye.

As is well-known to those skilled-in the art, it is necessary that the type bar shall be of minimum width in the direction of the axis on which it turns so that the number of bars required in a typewriting machine can be accommodated in the limited )HCG arailable which. in a visible t )ewritin machine wherein the bars are not superimposed, 1S considerable less than an arc of 190. Consequently, the bearing mean aforesaid, which are in the form of rings located within the eye of the type bar, must be very thin in relation to their diameter. Each ring provided with a surface at one edge constituting one wall of a ball race, which must he of maximum hardness for resisting wea and at its other edge with a thread for engaging" a complemental thread in the wall of the eye, or; a fixed support for the rin so that the ring may be moved in an axial direction for properly adjusting the bearing.

In order that a ball race, formed by a pair of ringbearing: members, may be of uniform size 'tlirou hout, so as to prevent undue cramping or the balls at certain points in the race as the bar oscillated, it is absolutely essential that the axes of the spirals of the threads in the rings shall be coincident with the axes of the cones of which the hardened bearing surfaces of the rings constitute sections. In the manufacture of these bearing members, it is necessary to cut the threads in the blank prior to subjecting the same to the hardening process for properly hardening the surface which is to constitute the wall of a ball race, and, owing to the thinness of the blank, this hardening treatment frequently results in the distortion thereof with a consequent twisting of the threaded edge in reference to the bearing surface, or a displacement of the axis of the spiral of the threads in ref ercnce to that of the cone, a section of which forms the bearing surface foresaid. My invention seeks to entirely eliminate this serious fault.

By my invention bearing members are composed of inner and, outer metal portions united together and of different character so that when one of said members, in the course of its manufacture, is submitted to one of the well-known hardening processes, one of the portions of the member hardens, and the other remains soft or relatively soft, and the bearing surface of said member Which engages the antifriction members, is formed upon the hardened portion thereof, and the miuzhined surface, as the peripheral threads,

for supporting or securing the bearing member in the eye of the type bar, or con necting' the same to a suitable support, is formed on the softer portion of the bearing member concentric with the hardened bearing surface and after the formation of said hardened bearing surface.

The inner and outer portions of the bearnan! ing member may be formed of two different said other portion may be composed of a" relatively soft steel which will not harden to the same extent as the steel to be provided with a surface to engage the antifric-- tion members. Preferably, the inner .portion of the bearing member is hardened and provided with a bearing surface for engaging the antif'riction members, and the outer portion is soft, or relatively soft, and is provided with a machined surface, as a threaded surface, for engaging a suitable support, as the eye of a type bar, but obviously the outer portion may-be formed of the hardening metal, and the inner portion of the soft, or relatively soft, metal, in which event, the surface for engaging the antifriction members will be provided on the outer portion of the bearing member,

and the securing surface will be provided on the soft inner portion of said bearing member.

A hearing member, constructed as described, is not only readily machined to form the securing surface therefor after the hardening of the portion of the bearing member which resists the wear of the antifriction members, but such a bearing member is liable to only a minimum amount of distortion since the softer metal holds the hardening metal in place to a greater or less extent, and further, such a member is absolutely true when in use, since the retaining surface is formed after the bearing surface and true relatively thereto.

1 and 2 designate respectively the inner and outer portions of a bearing member embodying my invention; and 3 and 4 desig-.

nate respectively the finished bearing surface provided on the inner hardened portion 1, and the finished securing or threaded surface provided on the outer soft portion 2.

5 is the threaded eye of a type bar coacting with the threaded peripheries of the bearing members; and 6 are the antifriction members, or balls, engaging the surfaces 3 which form a raceway for said balls, and

also engaging a suitable support 7. The eye 5 is preferably split transversely and provided with projecting ears and a screw 8 passed through said ears for clamping the bearing members in their adjusted position in the eye 5.

The blanks constituting the subject-matter of this application are preferably formed by suitable tools, such as those of a turret lathe, from a bar or other piece having an internal core 9 of steel suitable for hardening, and an external shell or Wrapper 10 of material resisting hardening, or material hardening to a less extent than the core 9.

i In Fig. 3, I have shown a portion of such a bar and the internal cavity formed therein by one or more of the machine tools operating to produce the blank from which my bearing member is formed, a line 11 indicating the plane in which a cutoff tool operates to sever the partially finished bearing member from the bar. ,The partially formed blank, cut, as described, from a bar such as illustrated in Fig. 3, is hardened by any well known process, such as the case-hardening method, or by heating the same and cooling in water, oil or other fluid. In the hardening process, the inner portion of the blank becomes hard, and the outer portion thereof remains soft, or relatively soft, and as previously stated, the outer soft, or relatively soft portion,'tends to minimize the amount of distortion of the bearing member due to its subjection to the hardening process. The bearing surface 3 is then formed upon the blank by suitable tools, such as a chuck 12 and a rotating grinding tool 13, as shown in Fig. 5. The end face of the bearing member meeting the larger end of the surface 3 is trued or faced by a grinding tool 14, preferably, while said member is held by the chuck 12. After the formation of the surface 3, suitable tools operate to form the surface 4 concentric with said'surface 3, such tools coacting with the surface 3 and the trued end face of the bearing member to support the blank on said surface 3 in order that the surface i may be absolutely concentric with the surface 3 or the axis of the spiral of the thread coincident with the axis of the cone of which the surface 3 is a section.

In Fig. 6, I have indicated by dotted lines, a spring centering mandrel 15 having a conical face 16 for engaging the face 3, and opposing members 17 and 18 for clamping the bearing member andholding the same upon the mandrel 15, and I ha e shown .diagrammatically a threading or chasing tool 19 for forming the threaded surface 4.

To those skilled in the art, it will be readily apparent that bearing members constructed from blanks embodying my invention, are particularly accurate and efficient in operation.

l/Vhat I claim, is

1. A blank for forming a thinringshaped bearing member of a type bar, said blank having the wall of a ball race at one edge thereof and a surface to receive a thread in its other edge, said blank being formed in two sections, the one having the ball race being, hardened to a greater degree than the other, substantially as and for the purpose described. 7 Y

2. A blank for forming a thin ringshaped bearing member of a type bar, said blank comprising an inner section provided at its inner edge with a ball race wall constituting the section of a cone, and an outer section united to the periphery of the inner section, and of a material which hardens to a lesser degree than the inner sections when the blank is subjected to a hardening process, said outer section having a periphery for receiving a screw thread, suhstantiall; as and for the purpose specified.

In testimony whereof, I have hereunto signed my name in the presence of two attesting witnesses, Syracuse, in the count of Onondaga, in the State of New Yorl this 26th day of January 1912.

ALEXANDER T. BROWN.

Witnesses C. E. Tonnnzson, Ixnz A. STILWELL.

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