US2937053A - Frictionless pivot - Google Patents

Description

May 17, 1960 R. N. RIGNEY FRICTIONLBSS PIVOT Filed Feb. 3, 1958 Blew/412D JV: E/ca-A/Ey,

' INVENTOR- United sates Patent FRICTIONLESS PIVOT Richard N. Rigney, Anaheim, Calif., assignor to Task fol-partition, Anaheim, Calif., a corporation of Caliornia Application February 3, 1958, Serial No. 713,061 16 Claims. (Cl. 308-2) connection therewith exactly fixing the location ofthe load member with respect to the base. At the same time,

the body is adapted to pivot frictionlessly and to at least? a limited extent about a transverse pivot axis in response to endwise applied loading acting about that axis, while transmitting, without flexing, applied loading acting or directed through the pivot axis, say at anormal thereto.

In accordance with the invention the bodyincludes-a' pair of flexure parts, typically web shaped, that transversely overlap one another along a transverse pivot axis intersecting the webs, for individually transmitting a portion and collectively transmitting all of the force application acting through that axis. The web parts are relatively angled respecting the direction of force transmis sion therethrough, and are relatively thin normal to the pivot axis.

cated with respect to opposite ends of the body by the very limitedextent of transverse overlap v of the thin web s.

provision of interengageable stop shoulders located on the body to limit flexing of the thin webs so that the.

latter will not flex or bend to produce bending stresses in excess of the yield strength in bending of the metal.

These shoulders are provided at longitudinally opposite As a result, the webs are adapted to flex in' response to force application to the body acting about the pivot axis, which is substantially exactly defined and An important feature of the invention concerns the 2,937,053 Patented May 17, 1960- ice . 2 Fig. 5 is'a perspective illustration of the frictionless pivot body. r

In the drawings the frictionless pivot body 10 is shown to have generally rectangular faces 11, rectangular opposite ends 12 and opposite sides 13, the thickness of the body between opposite faces 11 being considerably less than the lengths of the opposite sides and ends of the body.

Sunk into each face of the metallic body is a pair of cylindrical recesses 14 having transversely extending parallel axes '15, the locations of the recesses being such that each recess sunk into either body face overlaps and openly communicates with both recesses sunk into the opposite body face. The equal radii of the two recesses sunk intoeach body face are each slightly shorter than one-half the distance between the parallel transverse axes 15, whereby thin flexure parts or webs 16 of metal remain extending normal to lines between the axes 15 and also at angles to the longitudinal axis 17 of the body. The two webs 16 between'the pairs of recesses overlap one another along a transverse pivot axis 18, as seen in Figs. 3 and 4, the axis intersecting the webs along their The two webs 16 are also relatively transverse widths. angled respecting the direction of force transmission therethrough, and being very thin along the pivot axis 18 they substantially exactly locate that axis. As viewed in the drawings, the Webs have lengthwise extent making equal and opposite angles A with the lengthwise axis 17 of the body and at opposite sides thereof. Since the recesses 14 are cylindrical, the webs have rapidly increasing thickness in lengthwise directions. extending normal to axis 18,-and as a result, the axis of pivoting or flexure is substantially exactly located at the transverse overlap of the two webs.

As partly viewed'in Figsl' 3 and 4, the 'two webs are transversely spaced apart by virtue of the fact that each pair of the recesses. is formed as by drilling into a body face to equal'dpthsgreater than one-half the transverse thickness of the body, the inner terminal face 20 of each recess defining a longitudinal plane at, which the opposite webs 16 terminate at 21. After the recesses are drilled,

the transverse extent of web metal between planes 20 may be removed to separate the flexure parts 16 at their transverse overlap location, as seen in Figs. 3 and 4.

Drilled into each opposite end 12 of the body is a' pair of fastener openings 22 provided with screw threads for receiving fasteners 23 rigidly connecting one end' of sides of slots extending inwardly from opposite body sides to intersect recesses sunk into opposite body faces at opposite sides'of the webs, as will be described in detail.

These andother features and objects ofthe invention} as Well as the details of an illustrative embodiment .will

be more fully understood from the following detailed description of the drawings, in which:

Fig.1 is an elevation showing a frictionless pivot supporting and locating, a load member with respect to a bore for limited pivoting of the load member;

Fig. 2 is an enlarged elevation showing the appearance of one outer face of the frictionless pivot body;

Fig. 3 is a section taken on .line 3-3 of Figs-2;

Fig. 4 is a section taken on line 4-4 of Fig. 2; and v V the body with the base 24 and the opposite end of the body with a load member 2.5.- The threaded openings are transverselystaggered as viewed in Fig. 4 so as to intersect the inner faces 20, thereby providing screw threads sunk into those faces as viewed in Fig. 2. Thus,

the fasteners may grip the body-throughout the major extent of the threaded openings forrigidly connecting the body with the base 24 and load member 25.

One form of load member 25 isillustrated in Fig. l as" receiving eccentric loads F and F acting at angles to thelongitudinal axis '17 of the body 10. In general, any' such loading can be resolved into a load acting-through and angularly relative to the pivot axis 18 of the body and transmitted by'the webs 16, and a load acting about that axis. The latter force will produce flexing of the webs 16 if the latter are free to bend. This, freedom is provided by the slots 26 extending inwardly from opposite body sides 13,- each slot intersecting two of the recesses. surik"v respectively into opposite body faces, thereby separating.- W the body into similar upper and lower sections 27 and28i' respectively. Section 27, being rigidly connected with load member 25, is free. to pivot-in opposite directions about axis 18 with respect to the lower body section 28 rigidly connected to the base 24. Such pivoting is limited, however, by alternate interengagement of stop shoulders 29 and 30 at longitudinally opposite sides of the slots. Preferably the equal thickness dimensions of the slots in the longitudinal direction and when the webs are not flexed is such astointerrupt bending of the webs before the stresses produced therein by bendingand load transmission therethrough exceed the yield strength of the material. Thus, for. the Fig. 2 body configuration, the slots may be several times thicker than the webs, which would normally have minimum thickness of a few thousandths of an inch at their intersections with axis 18.

It will be understood that where a load member such as 2'5 is to be pivotallysupported for load testing purposes, intcrengagement of the stop shoulders 29 and Sflvwould defeat the ends sought to be gained by .suchpivotal supporting. Therefore, some means is provided for loading memberfi fas .by a known weight32 shiftable along horizontal surface 33 0f the body toward and away from axis 17, so as to cause the stop shoulders 29 and 30 to disen gage or separate by a predetermined amount indicating that the load member 24 is exactly pivotally supported without any flexure of the webs 16. For this purpose, the distance between the stop shoulders 29 and 30 may be predetermined as by introduction of gauges therebetween prior to loading of member 25.- After such loading the weight may then be shifted until insertion of gauges between the shop shoulders indicates that the Webs are unfiexed. At this point, the webs do not exert any torque or moment of force upon the member 25, and the latter is then frictionlessly pivotally supported.

I claim:

'1. A frictionless pivot, comprising a body having oppo site ends for receiving endwise application of force and including a pair of variable thickness flexure parts transversely overlapping one another along a transverse pivot axis intersecting said parts for transmittingforce through said axis andangularly relative thereto, said parts being relatively angled respecting the directions of force transmission therethrough and being relatively thin along said axis at said intersections whereby saidparts are adapted to flex in response to force application tto the body acting about said axis, and closely spaced interengageable stop shoulders on said body for limiting flexing of said parts.

.2. A frictionless pivot, comprising a body having opposite ends for receiving endwise application of force and including a pair of flexure parts transversely overlapping one another along a transverse pivot axis intersecting said parts for transmitting force through said axis and angularly relative thereto, said parts being relatively angled respecting the directions of force transmission therethrough and being relatively thin along said axis at said intersections whereby said parts are adapted to flex in re- 4. A frictionless pivot, comprising a body having opposite ends for receiving endwise application of force and including a pair of flexure parts transversely overlapping one another along a transverse pivot axis intersecting said parts for transmitting force through said axis and angularly relative thereto, said parts being relatively angled respecting the directions of force transmission therethrough and being relatively thin along said axis at said intersections whereby said parts are adapted to flex in response to force application to the body acting about said axis, said parts having increasing thickness in directions extending away from said intersectionsand normal to said pivot axis, and spaced interengageable stop shoulders on said body for limiting flexing of said parts.

5. A frictionless pivot, comprising a body having opposite ends for receiving endwise application of force and including a pair of flexure parts transversely overlapping one another along a transverse pivot axis intersecting said parts for transmitting force through said axis and angularly relative thereto, said parts being relatively angled respecting the directions of force transmission therethrough and being relatively thin along said axis at said intersections whereby said parts are adapted to flex in response to force application to the body acting about said axis, said body containing recesses at opposite sides of said parts, and spaced interengageable stop shoulders on said body for limiting flexing of said parts, said body containing slots extending between said reccssesand opposite sides of said body.

6. A frictionless pivot, comprising a metallic body having opposite ends for receiving longitudinally endwise application of force and including a pair of flexure webs transversely overlapping one another along a transverse pivot axis intersecting said Webs for individually transmitting a portion of the applied force through said axis and angularly relative thereto, said webs being relativ'ely angled respecting the directions of force transmis- ,sion therethrough and being relatively thin along said sponse to force application to the body acting about said axis, said body containing circular recesses at-opposite sides of said parts normal to said pivot axis, and closely spaced interengageable stop shoulders on said body for limiting flexing of said parts. r

.3. A frictionless pivot, comprising a bodyhaving opposite ends for receiving endwise application of force and including a pair of flexure parts transversely overlapping one another along a transverse pivot axis intersecting said parts for transmitting force through said axis and angularly relative thereto, said parts being relatively angled respecting the directions of force transmission therethrough and being relatively thin along said axis at said intersections whereby said parts are adapted to flex in reponse to force application to the body acting about said axis, said body containing recesses at opposite sides of said parts, and said opposite sides of said parts being concave and spaced 'interengageable stop shoulders on said body for limiting flexing of said parts.

axis at said intersections whereby said webs are adapted to flex in response to force application to the body acting about said axis, said body containing cylindrical recesses at opposite sides of said webs, and longitudinally closely spaced interengageable stop shoulders on said body for limiting flexing of said webs.

7. The invention as defined in claim 6 comprising two pairs of recesses respectively sunk into opposite faces of said body.

8. The invention as defined in claim 7 in' which each recess sunk into either body face overlaps and openly communicates with both recesses sunk into the opposite body face.

9. The invention as defined in claim 8 in which said body contains a pair of slots extending inwardly from opposite body sides, each slot intersecting two of said recesses respectively sunk into opposite body faces.

10. The invention as defined in claim 9 in which said webs are transversely spaced apart.

11. The invention as defined in claim 7 comprising a one-piece body. a

12. The invention as defined in claim 11 in which said body faces are rectangular in outline.

13. The invention as defined in claim 12 in which opposite ends of said body contain openings forrcceiving fasteners connectinga load member to the body.

14. A frictionless pivot, comprising a metallic body in response to force application to the body acting about said axis, said body containing two pairs of substantially cylindrical recesses respectively sunk into opposite body faces at opposite sides of said webs. V

15. The invention as defined in claim 14 in which each 5 recess sunk into either body face overlaps and openly communicates with both recesses sunk into the opposite body face.

16. The invention as defined in claim 15 in which said body contains a pair of slots extending inwardly from 10 opposite body sides, each slot intersecting two of said recesses respectively sunk into opposite body faces.

References Cited in the file of this patent UNITED STATES PATENTS 2,611,660 Hadley Sept. 23, 1952 2,793,028 Wheeler May 21, 1957 FOREIGN PATENTS 743,764 Great Britain J an. 25, 1956

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