US2907563A - Pivot - Google Patents

Description

6, 1959 c. D. VERDE ETAL 2,

PIVOT 2 Sheets-Sheet 1 Filed May 1957 mum INVENTORS C/MYZES 0 BY M P Oct. 6, 1959 Filed May 23, 1957 2 Sheets-Sheet 2 4 H b l FL I 4 5 iii": 5 3

1NVENTOR$ 00 x68 Q 12m BY A41 5 1 04/45? United States Patent @ilice 2,907,563 Patented *Oct'. 6, 1959 PIVOT Application May 23, 1951, Serial No. 661,236 6 Claims. c1. 2 7-1 The present invention relates to a pivot and more particularly to an improved pivot in which friction is substantially eliminated.

Ordinary pivots utilize two or more bearing surfaces whichare in engagement with each other and are moved relative to each other when the. pivot is to be turned. A ball and socket pivot is illustrative of such pivots. Although the etficiency of such pivots is reduced by the friction between the bearing surfaces, they have been generally acceptable for most purposes. However, when pivots are used for measuring devices, it has been found that friction often alters the readings of the instruments and even where compensation is made for the friction, the readings are never absolute because the user does not know how much friction exists at a particular mornent.

The present invention eliminates these defects and has for one of its objects a pivot in which friction is substantially eliminated. e 1 Another object of the present invention is to provide an improved pivot which does not utilize a plurality of bearing surfaces.

Another object of the present invention is to provide an improved pivot in which there is no frictional contact between the turning surfaces.

I A further object of the present invention is to provide an improved pivot which is simple to use and inexpensiveto manufacture. e o

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

A preferred embodiment of the invention has been chosen for purposes of illustration and description and is shown in the accompanying drawings, forming a part of the specification, wherein: p

Fig. 1 is a perspective view of the pivot of the present invention;

Fig. 2 is a sectional view showing the component parts of the pivot; e

Fig. 3 is a plan view of the pivot when the pivot is at rest; v t

Fig. 4 is a plan view of the pivot showing its position when in operation;

Fig. 5 shows one mechanism to which present invention can be applied;

-Fig. 6 shows another application of the present vention;

Fig. 7 shows one modification of the pivot of the present invention; and

Fig. 8 shows a second modification thereof.

Referring more particularly to Figs. 1 to 4, the present invention provides a pair of central portions 1 and 2 lconnected together by a plurality of U-shaped members 3. The hub portions 1 and 2 are preferably in axial the pivot of the alignment with each other and are shown in the drawingsas being circular in cross section. It will be understood, however, that the hub portions 1 and 2 can assume other shapes if so desired. The U-shaped connecting members li have one leg 4 embeddedwin' one of the hub portions (hub 1 for example) and the other leg 5 embedded viscosimeter for measuring the viscosity of fluids.

2 e in the other hub portion (hub 2 for example). These U-shaped members 3 are preferably made of leaf spring resilient material so that they may be easily flexed without losing their original shape. The free ends of legs 4 and 5 are connected together by a cross member 6. Preferably, the U-shaped spring elements 3 are made of a single piece of metal so that the legs 4 and 5 and the connecting member 6 will be integral with each other as shown in the drawings.

The hub portion 1 has a threaded stud 7 which can be anchored in any convenient manner to fix the hub portion 1 against rotation. The other hub portion 2 has an opening 8 in which a shaft may be mounted and held there by set screw 9 and is adapted to rotate on its axis relative to the fixed hub 1 when a turning force is applied to the shaft (not shown) in the opening 8. In effect, the portion 1 is a fixed hub whereas the hub portion 2 is a floating hub adapted to turn by means of the spring member 3. Also it will be noted that the hub portion 2 becomes in effect a part ofthe shaft (not shown) and will turn with it. It will be seen that when a turning force is applied to the floating hub portion 2, the leg 4 of the U-shaped members 3 will be flexed in one direction and the leg 5 will be flexed in the other direction, as shown in Fig. 4, so as to permit the floating hub 2 to turn on its axis relative to fixed hub 1. Since it is well known that when a spring bends there is no friction, it will be seen that the present invention provides a pivot in which friction is reduced to a minimum, as compared to the pivots of the prior art which depended upon frictional engagement between two bearing surfaces and which produced enormous amounts of friction. Also, since there is no friction, no heat is generated and therefore no cooling means need be provided for the pivot of the present invention.

It will also be readily seen that the two hub portions 1 and 2 are held in axial alignment with. each other by the U-shaped connecting members 3. The spatial relationship between the two hub portions 1 and 2 is fixed by the cross member 6 connecting the two legs 4 and 5 of the U-shaped connecting member 3. This will prevent the pivot from sagging.

It will be noted that three U-shaped members 3 have been shown in the drawings for connecting the hub portions together. While this is the preferred number of U-shaped members, it will be understood that any number may be used.

Fig. 5 shows the use of the present invention on a The hub portion 1 has its threaded stub 7 fixedly mounted on a frame member 11 above the viscosimeter by a nut 12. The other hub portion 2 is free to tum and has a motor 13 mounted thereon by means of the shaft (not shown) of the motor being inserted in the central opening 8 (not shown) of the hub portion 2 and being held thereon by a set screw 9. The armature 14 of the motor has a bobbin 15 mounted thereon which sits in a cup 16 therebeneath. Fluid 17 is placed in the cup 16 so that it sits between the bobbin 15 and cup 16. The motor 13 is then started to turn the armature 14 and bobbin 15. The resistance of the fluid 17 to the turning motion of the bob bin 15 is translated to the motor 13 which is turned slightly by such resistance. This turning of the motor 13, the shaft thereof and the hub portion 2, is possible by the fact that the motor 13 is mounted on the floating hub portion 2 which turns with the motor 13 in effect as a part thereof on its axis relative to the fixed hub portion 1 by the flexing of the legs 4 and 5 of the resilient U-shaped members 3. Suitable measuring means can be attached to either the motor- 13 or the floating hub portion 2 to measure the amount of resistance set up by the fluidian'd thus determine its viscosity. It is important to note,

2,907,563 v I i however, that the slight turning of the motor 13 and floating hub portion 2 is not retarded by any friction .in

the pivot since the pivot is practically frictionless and therefore a reading of the resistance set up by fluid 17 will be anabsolute reading. TInrother Words, 'by .using the present invention .there .is .no :friction :to .be compensated for in order to obtain a viscosity measurement of .fluid 17. ZIt willalso be noted ;that.since the two legs 4.and 5 are connected together by across member-6, thefloating hub portion 2.011 which the motor 13 is mounted will not sag under the weight of motor '13.

Fig. 6 shows another application of the present invention. In Fig. 6 the improved pivot is used ,in connection with a laboratory scale. 'In this .case two pivots are used having their fixed hubs .1 fixedly mounted on suitable :frame members (not :shown) and a shaft 18 is mounted on'the two floatinghub portions 2. A lever 19 is fixedly attached to :the shaft .18 so that Whenasubstance 20 to be weighed is .placed on one end of the lever and a Weight .21 is placed on'another end, the floating hub portions 2 will turn by the .flexure of the legs '4 and 5 of U-shaped spring elements .3 to thereby register the weight of the substance 20. Here again, since there are no bearing surfaces, there is no friction and an absolute reading of the weight can be obtained.

Fig. 7 shows one modification of the present invention. Instead of using a U-shaped member 3 for connecting the two hub sections together and to'permit the floating hub 2 to turn relative to the fixed hub 1, a W-shaped spring member 20 is used. This gives the floating hub portion 2 a greater turning range since the flexibility of the W-shaped member 20 is greater than the flexibility of a U-shaped member. The operation of this modification is similar to the pivot shown in Figs. 1 to, 4.

Fig. 8 shows'still another modification of the present invention. In this instance, a plurality of hub portions 31, 32, and 33 are used. Each pair of hubportions is connected by a pluralityof U-shaped members 34 or 35.

The fixed hub portion 31 and an intermediate hub portion 32 are connected together by one series of U-shaped members 34 whereas the intermediate hub portion 32 and the .end hub portion 33 are connected by a second series of U-shaped members 35. The two groups of U-shaped members are offset .from each other, as shown in the drawings, so that the intermediate and end floating hub portions 32 and 33 will each turn on their axis relative to the fixed hub portion 31. This cascading of hub portions 31, 32, and 33 permits the pivot to be turned a greater number of degrees. Since no friction will be produced, the range of the present pivot can be increased without increasing friction.

It will be seen from the above that the present invention provides a pivot in which friction is substantially eliminated, which does not utilize any bearing surfaces and which is simple to use and inexpensive to manufacture.

As various changes may be made in the form, construction, and arrangement of the parts herein without departingfrom the spirit and scope of the invention and with- .outsacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in a limiting sense.

Having thus described our invention, we claim:

1. A pivot comprising a pair of central hub portions in axial alignment to each other, means for maintaining one of said central hub portions fixed, a W-shaped member connecting said central hub portions together, one leg of said W-shaped member being mounted on said fixed central hub portion and the other leg of said W-shaped member being mounted on the other central hub portion, said W-shaped member being resilient in a direction substantially concentric to the axis of one of said hubs to permit the other of said central hub port-ions to turn on its axis relative to saidfixed central hub portion.

of one of said hubs to permit said end and intermediate central hub portions ;to lturnon their axis relative to said fixed centralhub portion. 7

3. .A pivotas claimed in claim 2, wherein said .connecting members are U-shaped leaf springs.

4. A pivot comprising a pair of relatively rotatable central hub portions in axial alignment to each other means for maintaining one of said central hub portions fixed, a plurality of spaced, radially extending, flat, re silient,"leaf-spring, U-shaped members connecting said central hub portions together, each of said U-s'ha'ped members being substantially rigid in a radialplane, one leg of said U-shaped member being mounted on one "hub and the other leg being mounted on the other central hub portion, said 'U shaped member being resilient in a direction substantially concentric to the axis of one of said hubs to permit said other central hub portion "to turn on mounted on the other 'hub portion, said legs being mounted on said hubs in a plane perpendicular to the axis of the hubs, and being normally aligned with each other in a common plane, and said legs being resilient and adapted to bend in oppositedirections to permitone of said hub portions to turn on its axis relative to the other hub portions, the base of said U-shaped member being adapted to move inwardly when said hub -is rotated to prevent longitudinal displacement of the hubs.

6. A pivot comprising a pair of relatively rotatable central hub portions in axial alignment to each other,

means for maintaining one ofsaid hubs fixed, a'plurality of radially extending, thin, flat, one-piece, resilient, lwf spring, U-shaped members, each of said Ushaped members being rigid ina radial plane, each ofsaid members comprising a pair of legs and an integral base connecting said legs together, one of said legs being mounted on one of said hubs and the other leg being mounted onthe other of said hubs, said legs being mounted on said hubsin a plane perpendicular to the axis of the hubs and being nor mally aligned with each other in a common plane, and said legs being resilient to permit theother of said hub portions to turn on its axis relative to the fixed hub portion, the base of said U-shaped member being adapted to move inwardly when said hub is rotated and being-of sufficient stiffness to maintain the hub portions in a fixed spatial relationship toeac'h other.

References 'Citedtin the file of this patent UNITED STATES PATENTS 539,161 Almond May 14, 1895 1,214,307 Hosford Jan. 30, 1917 2,368,905 Wallace F6116, 194-5 2,441,267 Gulbrandsen May 11, 11-948 2,630,692 Naugler Mar. 10, .1953 2,735,731 Ereebairn-et a1 Feb. '21, .9.5.6

Klepp .Jan. V22, 1957 fixed central hub portion, an t

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