US2611661A - Pivot and bearing assembly - Google Patents

Description

Sept. 23, 1952 H. A. HADLEY PIVOT AND BEARING ASSEMBLY Filed March 7. 1949 INVENTOR.

HARLAN A. HADLEY,

ATTORNEY Patented Sept. 23, 1952 PIVOT AND BEARING ASSEMBLY Harlan A. Hadley, Burlington, Vt., assignor to H. A. Hadley Associates, Inc., Burlington, Vt., a corporation of Vermont Application March 7, 1949, Serial No. 80,025

12 Claims.

This invention relates to weighing scales, and relates more particularly to a knife edge pivot and bearing assembly adapted for use in weighing scales.

This invention is a modification of the invention shown in my application Serial No. 73,270, filed January 28, 1949.

In many weighing mechanisms, levers are supported and the forces are transmitted to and from the levers by means of knife edge pivot and bearing assemblies in which the knife edge pivot rests in a suitably mounted bearing provided with a V-groove. The V-groove normally positions the pivot in a longitudinal plane and anti-friction plates applied to the end of the bearing block normally restrain the pivot from endwise motion. As is well known, such pivot and bearing assemblies are not wholly satisfactory since their use leads to inaccuracies in weighing. Thus, since the V-groove must be made with a bottom having a slight radius to prevent frictional contact of the sides of the V-groove with the sides of the knife edge pivot. the knife edge pivot skates over the surface of the flattened bottom of the V-groove causing the lever to assume readily a different position for every different position of the knife edge pivot on the radius portion of the V-groove. The movement of the pivot relative to the radius portion of the V-groove alters the pivot distances, resulting in inaccuracies in the weighing.

It is an important object of this invention to provide an improved knife edge pivot and bearing assembly which will be free from the abovementioned and other disadvantages and which will be especially simple in construction and emcient in use.

Another object of this invention is to provide a knife edge pivot and bearing assembly wherein the knife edge pivot cooperates with a fiat bearing surface and wherein the pivot and the bearing are connected to each other to maintain the same in predetermined operative position relative to each other so that the pivot is free to turn on its normal axis but is restrained from movement in any other direction.

A further object of this invention is to provide an improved flexure member for holding the pivot and bearing in predetermined operative relation to each other.

Still another object of this invention is the provision of a novel flexure member and support arrangement for holding the pivot and bearing in predetermined operative relation to each other.

Other objects of this invention, together with certain details of construction and combinations of parts, will be apparent from the following description and will be pointed out in the appended claims.

In the drawing, wherein a preferred embodiment of my invention is shown,

Figure 1 is a perspective view of my novel knife edge pivot and bearing assembly,

Figure 2 is a front elevational view thereof, and

Figure 3 is a side perspective view of a fiexure member.

Like reference numerals indicate like parts throughout the several views of the drawing.

Referring now to the drawing for a detailed description of my invention, the reference numeral 4 indicates a bearing block in which is imbedded a bearing 5. The bearing 5 may be made of any suitable material of sufiicient hardness. Preferably. the bearing is made of Norbide, a compound of boron and carbon, ground to optical flatness.

Knife edge 6 may be integral with knife edge block I, or may be suitably held therein; and is preferably made of Carboloy, tungsten-carbon alloy. However, the knife edge may be made of steel or any other suitable material.

In accordance with the present invention, the knife edge 6 is maintained in proper position on the flat surface of bearing by means of a flexure member or members generally indicated by reference numeral 8. The flexure member comprises a pair of blocks 9 of any suitable metal, such as brass, copper, steel, or the like, having fixed between them a web of a resilient material II. While any suitable resilient material may be employed, I prefer to use an elastomer such as natural or synthetic rubber. The rubber web II is suitably bonded or welded to the blocks 9. For greater sensitivity, the rubber web I I is cut away substantially centrally thereof, as is shown at I2, in such a manner that the smallest cross-section of the web is in line with the knife edge 6.

To maintain the flexure members 8 in position with respect to the knife edge pivot and bearing assembly, each of the bearing blocks 4 and knife edge blocks I are provided with projections I3 which may be integral with their respective blocks. Flexure member supports I4 are attached to the knife edge and bearing blocks by means of bolts or pins I5 and are each provided with a seat I6 for the reception of the metallic blocks 9 of the fiexure member. One of such supports I4 is mounted on bearing block 4, with seat l6 facing downward, to one side of a vertical line passing through the center of the ends of blocks 4 and I, while its cooperating support is mounted on knife edge block I, with its seat It facing upward, on the opposite side of said vertical line. A pair of fiexure member supports may be similarly arranged on the other ends of blocks 4 and I.

A flexure member 8 is attached to each cooperating pair of supports I4 by means of screws I'I passing through openings I8 in the flexure member. Thus, the flexure members are operatively fixed in the pivot and bearing assembly in a horizontal position with respect thereto, 1. e. in a plane coextensive with the plane of the surface of bearing 5.

The embodiment of my invention shown and described herein is to be considered merely as illustrative, as my invention is susceptible to variation, modification and change within the spirit and scope of the appended claims.

I claim:

1. In a weighing scale having a pivot and bearing assembly, a flexure member for restraining the movement of the pivot relative to the bearing, said flexure member comprising an elastomer web and a metal block fixed to each end of said elastomer web and attached to said pivot and bearing assembly.

2. In a weighing scale having a pivot and bearing assembly, a flexure member for restraining the movement of the pivot relative to the bearing, said flexure member comprising a rubber web and a metal block fixed to each end of said rubber web and attached to said pivot and bearing assembly.

3. In a weighing scale having a pivot and bearing assembly, a flexure member for restraining the movement of the pivot relative to the bearing. said flexure member comprising an elastomer web and a metal block bonded to each end of said elastomer web and attached to said pivot and bearing assembly.

4. In a weighing scale having a pivot and hearing assembly, a flexure member for restraining the movement of the pivot relative to the bearing, said fiexure member comprising a rubber web and a metal block bonded to each end of said rubber web and attached to said pivot and bearing assembly.

5. A pivot and bearing assembly for weighing scales, comprising a block having a bearing surface, a block having a knife edge for engagement with said bearing surface, a flexure member for restraining the movement of said knife edge relative to said bearing surface, said flexure member comprising an elastomer web and a metal block fixed to each end of said elastomer Web, and means carried by said bearing surface and knife edge blocks for supporting the metal blocks fixed to said elastomer web in operative position.

6. A pivot and bearing assembly for weighing scales, comprising a block having a bearing surface, a block having a knife edge for engagement with said bearing surface, a fiexure member for restraining the movement of said knife edge re-lative to said bearing surface, said flexure member comprising an elastomer web, having a reduced cross-section substantially centrally thereof. and a metal block bonded to each end of said elastomer web, and means carried by said hear-- ing surface and knife edge blocks for supporting the metal blocks bonded to said elastomer web in operative position.

'7. A pivot and bearing assembly for weighing scales comprising a block having a bearing surface, a block having a knife edge for engagement with said bearing surface, a flexure member, said flexure member comprising a rubber web, having a reduced cross section substantially centrally thereof, and a metal block bonded to each end of said rubber web, and means carried by said bearing surface and knife edge blocks for supporting the metal blocks bonded to said rubber web in operative position.

8. A pivot and bearing assembly for weighing scales, comprising a block having a bearing surface, a block having a knife edge for engagement with said bearing surface, two projections carried by each of said blocks, and flexure members supported by said projections for restraining the movement of said knife edge relative to said bearing surface, each of said fiexure members comprising an elastomer web and a metal block bonded to each end of said elastomer web.

9. A pivot and bearing assembly for weighing scales, comprising a block having a bearing surface, a block having a knife edge for engagement with said bearing surface, two projections carried by each of said blocks, and flexure members supported by said projections for restraining the movement of said knife edge relative to said bearing surface, each of said fiexure members comprising a rubber web and a metal block bonded to each end of said rubber web.

10. A pivot and bearing assembly for weighing scales, comprising a block having a bearing surface, a block having a knife edge for engagement with said bearing surface, two projections carried by each of said blocks, and fiexure members supported by said projections for restraining the movement of said knife edge relative to said bearing surface, each of said flexure members comprising a. rubber web, having a reduced crosssection substantially centrally thereof, and a metal block bonded to each end of said rubber We 11. A pivot and bearing assembly for weighing scales, comprising a block having a bearing sin"- face, a block having a knife edge for engagement with said bearing surface, two projections carried by each of said blocks, and flexure members supported by said projections for restraining the movement of said knife edge relative tosaid bearing surface, each of said fiexure members comprising a rubber web and a metal block bonded to each end of said rubber web, the construction and arrangement being such that the fiexure members are supported by said projections in a plane substantially coextensive with the plane of said bearing surface.

12. A pivot and bearing assembly for weighing scales, comprising a block having a bearing surface, a block having a knife edge for engagement with said bearing surface, two projections carried by each of said blocks, and flexure members supported by said projections for restraining the movement of said knife edge relative to said bearing surface, each of said flexure members comprising a rubber web, having a reduced cross-section substantially centrally thereof, and a metal block bonded to each end of said rubber web, the construction and arrangement being such that the fiexure members are supported by said projections in a plane substantially coextensive with the plane of said bearing surface.

HARLAN A. HADLEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 392,617 Lieb Nov. 13, 1888 1,071,761 Leake Sept. 2, 1913 2,458,537 Skelly a. Jan. 11, 1949

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