US3253482A - Torque-biased rotatable member - Google Patents

Description

May 31, 1966 G. w, KNECHT 3,

TORQUEBIASED ROTATABLE MEMBER Filed Jan. 24, 1964 Fig. 1 (a) F13. 10 1 1 /2/02 Aer) (PIE/02 Aer) llliill-i-llllllllllll Fig Fig". 5

INVENTOR. ya d/e45 W/fl/Ech r BY www- ATTORNEY United States Patent 3,253,482 TORQUE-BIASED RGTATABLE MEMBER George W. Kneeht, Brooklyn, N.Y., assignor to Murray Manufacturing Corporation, Brooklyn, N.Y., a corporation of New York Filed Jan. 24, 1964, Ser. No. 340,055 7 Claims. (Cl. 74-526) This invention relates to a member pivoted within its periphery for angular displacement, and is directed to an arrangement for spring biasing the member relative its pivot.

In numerous applications electrical, mechanical, and electromechanical, it is often found desirable, if not necessary, to spring load apivoted member to ensure return to a home position subsequent to its being unlatched from a position to which it had been urged. The member itself may act, for example, as a lever, cam, armature, etc., however, the fundamental biasing principle remains the same. The handle mechanism in a circuit breaker is a simple illustration. Generally pivoted near its center, the handle is manually urged, activating the internal mechanism, to the set position in which it is latched. Upon being tripped in response to an overload in the external circuit, it is desirable that the handle return to the off position for indicating the condition of the breaker and initiating reset. It is often convenient to bias the handle itself to effectuate such a result.

Conventional biasing'arrangements take several forms. Since a discussion of two such arrangements, delineating their inherent disadvantages, will serve as an aid in un derstanding the advantages of the present invention, such a discussion follows.

FIGS. 1a and 1b illustrate conventional biasing arrangements for a lever and cam, respectively. In FIG. la the lever 2 is mounted upon pivot 1 and is biased clockwise by the spring 3. The relative simplicity of such an assembly lends itself to widespread employment, however, two disadvantages are immediately apparent. First, an extra lever arm is necessary for fulcruming the spring, and second, the spring itself lies outside the structure. The effect in either case is that an area which could be employed for another useful purpose is totally lost, without resorting to the utilization of a parallel adjacent plane. Since it is often desirable to maintain the thickness of the apparatus within minimum limits, the latter solution is not satisfactory.

FIG. lb provides a partial solution. By mounting the spring 6 internally of the cam 7 and adapting the spring to act in opposition on the cam '7 and pivot 5, rotational force is imparted to the cam without resort to an adjacent plane or additional area. This solution, however, is not totally satisfactory since a poor bearing surface between cam and pivot is created (if only partially), and any angular displacement causes a change in the diameter of the spring and consequently produces a pressure inwardly or outwardly (depending upon the direction of rotation). Moreover, both of the foregoing arrangements exhibit a non-uniformity in the torque exerted on the rotating body. This necessarily arises from the fact that the spring pressure varies, dependent upon the spring distortion or displacement.

Accordingly, it is the object of the present invention to substantially uniformly torque bias a rotatable, or pivotal member, and to do so in a minimum area without effecting poor bearing surfaces.

Briefly, the present invention is predicated upon the concept of internally torque loading the pivoting member relative the shaft or pivot by means of a rectilinear spring force acting through a variable moment arm.

The above mentioned and other features and objects of this invention and the manner of attaining them will "ice become more apparent and the invention itself will best be understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanyingdrawings wherein:

FIGS. 1a and 1b illustrate the conventional torque biasing arrangements previously alluded to;

FIGS. 2a and 2b show the torque biasing arrangement, in accordance with the present invention, in two positions of member rotation;

FIG. 20 shows a side exploded view of the arrangement and member position of FIG. 2a; and

FIG. 3 illustrates one embodiment of the described biasing arrangement.

In FIG. 2a the basic member 11 is depicted with-out embellishment. It will be appreciated, however, that it may, depending upon is functional requisites, constitute a lever, cam, etc., as will be apparent to those versed in the art. Further, although the member 11 is shown (in FIG. 2c) as mounted upon a pivot, it may as easily be mounted upon a long shaft, a portion of which takes the shape to be described. Moreover, it will also be apparent that although for simplicity the outer member is described as that to which rotation is imparted, that element may be rigidly maintained and the shaft or pivot angularly displaced.

Member 11 is provided with an irregular opening 12, adapted at the upper portion to embrace the pivot 10 and at the lower portion to provide a springway for the spring 13. The pivot accepting portion of the opening embraces a sufficient arcuate segment (over to ensure a firm bearing grip on the pivot; the latter of which has a pieshaped (or sector) section removed to provide a load surface for the upper end of the spring.

Because the spring is laterally displaced with respect to the pivot axis, the force exerted thereby acts through moment arm M to provide a torque which is a function of this parameter, and the spring pitch distortion (i.e. the axial distance through which the upper end of the spring is displaced).

FIG. 2b illustrates the effect of rotation upon the spring and moment arm. When the member 11 has undergone approximately 45 of clockwise rotation, the spring 12 has undergone a displacement d. It now acts through a new diminished moment arm M. arm and the spring distortion occur as a result of, and are dependent upon, the lateral displacement of the springway and the size of the removed pivot section. While each may be varied from the preferred values shown (in which the displacement is approximately equal to pivot radius, and the segment of pivot removed is approximately 1r/2 radians) within practical limits, it is apparent that since the torque is a product of the spring force and moment arm, which always vary inversely, the torque itself remains substantially constant within a predetermined angle of displacement.

A novel handle mechanism, such as might be found in a circuit breakeremploying the inventive concept, is shown in FIG. 3. In rotating the handle 17 from the off displacement limit 18 to the on displacement 18' a toggle assembly consisting of lower portion 16 of the handle, the pivot 20, and the arm 15, is urged to the left. Simultaneously, the torque biasing arrangement 10, 12 and 13 assumes the position shown in FIG. 212. When over current persists in the breaker, the toggle releases (not shown) and the handle mechanism by virtue of its internal biasing returns to the off position, rotating the toggle assembly to the right preparatory to reset.

By employing the constant torque bias of the invention the internal mechanism may itself be made more efficient without necessitating compensating or over compensating arrangements to obviate the increased bias ordinarily produced in the on position.

Both the new moment While I have described above the principles of my invention in connect-ion with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of my invention as set forth in the objects thereof and in the accompanying claims.

What is claimed is:

1. A rotatable member adapted to be torque biased comprising in combination: a body having a cylindrical bore perpendicularly intersecting at least one surface, and a springway substantially perpendicular to the bore axis and laterally disposed with respect thereto for intersecting at one end of said springway a substantial arcuate segment of said bore; and a cylindrical pivot, having a single sector cutout, dimensioned for slidable entry into said bore, said body thereby being angularly displaceable on said pivot.

2. A pivotal torque loaded member comprising in combination; a cylindrical pivot having a sector cutout; a body angularly displacea'ble on said pivot having a cylindrical bore perpendicularly intersecting at least one surface for slidably accepting said pivot and a springway substantially perpendicular to the bore axis and laterally disposed with respect thereto for intersecting at one end of said springway a substantial arcua-te segment .of said bore; and a spring disposed in said springway and bearing upon one surface of said cutout and the other end of said springway.

3. The pivotal torque loaded member claimed in claim 2 in which the lateral disposition is a distance equivalent to the pivot radius.

4. The pivotal torque loaded member claimed in claim 2 further comprising means for limiting the angular displacement of said body.

5. The pivotal torque loaded member claimed in claim 2 in which the said bore intersecting surface of said body is substantially planar.

6. The pivotal torque loaded member claimed in claim 2 in which said body has two parallel planar surfaces, both of which intersect said bore and said springway.

7. A handle mechanism for breaker assemblies comprising in combination a cylindrical .pivot, having a sector cutout; a handle body angularly displaceable on said pivot having two substantially parallel planar surfaces, said body having a cylindrical bore perpendicularly intersecting at least one of said surfaces for slidably accepting said pivot and a springway substantially perpendicular to the bore axis and laterally disposed with respect thereto for intersecting at one end of said springway a substantial arcuate segment of said bore; a spring disposed in said springway and bearing upon one surface of said cutout and the other end of said springway; and means for limiting the angular displacement of said handle body.

References Cited by the Examiner UNITED STATES PATENTS 651,706 6/1900 Forbes 6429 X 1,061,293 5/1913 Huye 74-592 1,190,888 7/1916 Gordon 20067 1,457,711 6/1923 Mikkelson. 1,685,310 9/1928 Burrell et al. 74-528 2,656,018 10/1953 Bent et al. 74566 .X 2,871,721 2/1959 Abra moska et al. 74566 3,083,932 4/1963 Crowley et al 254 BROUGHTON G. DURHAM, Primary Examiner.

CAROLYN F. GREEN, Assistant Examiner.

Claims (1)

1. 7. A HANDLE MECHANISM FOR BREAKER ASSEMBLIES COMPRISING IN COMBINATION A CYLINDRICAL PIVOT, HAVING A SECTOR CUTOUT; A HANDLE BODY ANGULARLY DISPLACEABLE ON SAID PIVOT HAVING TWO SUBSTANTIALLY PARALLEL PLANAR SURFACES, SAID BODY HAVING A CYLINDRICAL BORE PERPENDICULARLY INTERSECTING AT LEAST ONE OF SAID SURFACES FOR SLIDABLY ACCEPTING SAID PIVOT AND A SPRINGWAY SUBSTANTIALLY PERPENDICULAR TO THE BORE AXIS AND LATERALLY DISPOSED WITH RESPECT THEREOF FOR INTERSECTING AT ONE END OF SAID SPRINGWAY SUBSTANTIAL ARCUATE SEGMENT OF SAID BORE; A SPRING DISPOSED IN SAID SPRINGWAY AND BEARING UPON ONE SURFACE OF SAID CUTOUT AND OTHER END OF SAID SPRINGWAY; AND MEANS FOR LIMITING THE ANGULAR DISPLACEMENT OF SAID HANDLE BODY.

Images