US1954197A - Scale pivot - Google Patents

Description

April 10, 1934. J. BRQWN 1,954,197

SCALE PIVOT Filed April 6, 1931 James D. Brown INVENTOR.

A TTORNE Y.

Patented Apr. 10, 1934 UNITED STATES SCALE PIVOT James D. Brown, Toledo, Ohio, assignor to Toledo Scale Manufacturing Company, Toledo, Ohio, a corporation of New Jersey Application April 6, 1931, Serial No. 527,867

4 Claims.

This invention relates to knife edged pivots and particularly to improved means for retaining such knife edged pivots in levers or other scale members. The cross section of a pivot of the type with which my improved retainer is to be employed is substantially a sector of a circle having a diameter substantially equal to the diameter of an accurately bored hole in the scale lever or other part. Retainers similar to the one in which my invention resides have been proposed; these, however, were very costly, especially if used in connection ,with pivots for heavy capacity levers, as they were machined from a solid bar of metal. This naturally entailed considerable waste of material and costly machining and grinding operations. I have provided a retainer which is made of laminae punched from scrap sheet steel or other metal. The material cost of such retainers is extremely small. The machine Work being performed main- 1y on a punch press and the grinding eliminated to a great extent, the labor cost is therefore also greatly reduced to a minimum.

The principal object of my invention is the provision of a scale pivot retainer which may be 5 easily and economically manufactured.

Another object is the provision of means for producing a pivot retainer from scrap metal stock.

A further object of the invention is the provision of means for producing a scale pivot retainer in which the machining cost is reduced to a minimum.

A still further object of the invention is the provision of a pivot retainer made from sheet metal stampings.

These and other objects will be apparent from the following description in which reference is had to the accompanying drawing and in which similar reference numerals designate similar parts throughout the several views.

In the drawing:--

Figure I is a side elevational view of a scale lever of a well known type embodying my invention and the co-operating fulcrum and load brackets.

Figure II is an enlarged fragmentary side elevation of a portion of the lever showing my improved method for retaining a pivot.

Figure III is an enlarged cross sectional view 0 substantially along the line III-III of Figure II;

and

Figure IV is a perspective view showing the pivot and the retainer, parts in disassembled relation.

Referring to the drawing in detail, the lever l is of a well known type and as the use of such levers in weighing scales is well known, I have not shown it connected to other weighing mechanism. The portion 2 of the lever in which the pivots are retained by the means embodying my invention is bifurcated and an accurately circular bore 3 is machined through the two arms 2, 2. The cross sectional shape of a pivot 4 is substantially that of a sector of a circle of substantially the same diameter as that of the circular bore 3. It

is obvious that when this pivot is placed in the bore, its knife edge will be coincident with the axis thereof, and the length of the-pivot is so calculated that it extends through the arms 2, 2 of the lever l.

The improved retainer 5 comprises a series of 7 body laminations 6 which are adapted to be stamped completely from scrap sheet steel. These body laminations are slightly smaller than the two end laminations 7 and 8 which are designed to contact the walls of the bore. The laminations 6, '7 and 8 are adapted to be riveted together by the rivets 9 forming a substantially integral memher.

A V-slot 10 is provided in each of the laminations and its included angle is that of the angle of the pivot. The lamination 8 has a conical portion 11 formed outwardly, the apex of which is coincident with the apex of the V-slot. The apex 11, when the retainer is slipped in the bore is coincident with the pivot edge and forms a 35 thrust for the bearings 12 which are secured in a bracket 13 and which supports the platform of the scale (not shown). After the laminations, forming the retainer, are riveted together, it is an easy matter to locate it into a properly de- 0 signed fixture on a grinding machine and accurately grind those portions of the laminations '7 and 8 which contact the walls of the bore. The method of retaining the pivot is shown in Figure II. The retainer is adapted to straddle the pivot 4 and a substantially semi-circular clamping member 15 is placed thereon so that it contacts the laminations 6 which do not touch the walls of the bore. Clamping screws 14 are threaded through apertures in the lever extending at a 0 right angle to the axes of the bores and are adapted to securely lock the pivot 4 against movement in the direction of their longitudinal axes. Sidewise movement of the pivot is prevented by the portions of the laminations 7 and 8 which 10 contact the wall of the bore. It is obvious that a pivot retainer constructed according to the illustrated embodiment of my invention is very economically produced and well adapted to fulfill the objects primarily stated.

It is to be understood, however, that the invention is susceptible to variation, modification, and change within the spirit and scope of the subjoined claims.

Having described my invention, I claim:

1. In a scale member, in combination, a member having a circular bore, a knife edged pivot located within said bore and a retainer for locking said pivot therein, said retainer comprising a plurality of substantially similar metallic laminae, all of said laminae being adapted to contact said knife edged pivot and certain of said laminaebeing adapted to contact the wall of said circular bore.

2. In a weighing scale,having'a lo adsupporting lever with a bifurcatedehdcolinearboresin said bifurcations, a pivot stationed within'said bores, and retainers, said retainers each comprising a plurality of substantially flat laminae cooperating with locking means in said lever, each of said retainers having a substantially V-shaped notch and the end lamina having a protruding portion with its apex coincident withthe apex of the V-notch.

5 3. In a scale member, a portion'having a circular bore, the axis of whichlies in a horizontal position, a knife edgedpivot'located within said bore and resting against the wall thereof, the

knife edge of said pivot being coincident with the axis of said bore, a retainercomprising a plurality of laminae, portions of the contour of each of said laminae defining a V to engagethe sides of the knife edged pivot, the remainderof the contour of said lamina being defined by radii,

radii defining portions of the contour of two of said laminae being larger than the radii defining similar portions of the contour of the other of said laminae, portions of said lamina having larger radii being adapted to engage the wall of said circular bore to prevent lateral movement of said knife edged pivot, means for holding said laminae together, and means for locking said lamina in said bore whereby the knife edge of 'the pivot is invariably held coincident with the axis of the bore.

'4. In a scale member, a portion having a circularibore, the axis of which lies in a horizontal position, a knife edged pivot located within said fbore and resting against the wall thereof, the knife edge .of said pivot being coincident with the axis of said bore, a retainer comprising a plurality 'of laminae, portions of the contour of each of said laminae defining a V to engage the sides of the'knife edged pivot, the remainder of the contour of said laminae being defined by radii, radii 'defini'ngpo'rtions of the contour of two of said. laminae being larger than the radii defining similarfportions of the contour of the other of said'laminm, said portions of said two lamina 'having'i larger radii being adapted to engage the

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