GB2192249A

GB2192249A - Locking nut

Info

Publication number: GB2192249A
Application number: GB08713270A
Authority: GB
Inventors: Frank J Cosenza; Roy L Warkentin
Original assignee: Rexnord Inc
Current assignee: Rexnord Inc
Priority date: 1986-07-01
Filing date: 1987-06-05
Publication date: 1988-01-06
Anticipated expiration: 2007-06-05
Also published as: GB2192249B; DE8709114U1; FR2601090A1; GB8713270D0

Abstract

A threaded locking nut 20 comprises a plurality of resilient beams 22 configured such that most of the confronting side walls 27 and 28 of adjacent beams 22 diverge radially outwardly so that any debris located between the confronting side walls 27, 28 of adjacent beams 22 does not inhibit movement of the beams from a locked, expanded position engaged with a bolt to a free, inwardly-tapered position when the bolt is withdrawn. The inner part of the side walls 27, 28 may be parallel to each other. The inner surfaces of the beams 22 have a radius of curvature greater than that of the bolt so that there is only point contact at each thread turn. <IMAGE>

Description

SPECIFICATION Locking beam unit BACKGROUND OF THE INVENTION The present invention relates to lock nuts having a plurality of resilient locking segments which deflect in a manner similar to that of a beam, and, more particularly, to a construction of the locking segments such that the slotted area between adjacent locking segments is self-cleaning.

The present invention is an improvement in the design of the patented "LOCK NUT MEM BER" described in U.S. Patent 3,702,628 which issued on November 14, 1972 to Frank J. Cosenza. Subsequent to that invention it was determined that the performance of the lock nut, as well as other lock nuts of similar function, is affected by debris which accumulates in the slotted area between the opposing side walls of adjacent locking segments or beams, as they will hereinafter be referred to.

Debris, e.g., oil, dirt, etc., which for a variety of reasons is found in the environment in which the lock nut is used, is extruded or removed from the interior of the lock nut by the threading action of the nut and bolt pushing the debris outwardly into the slotted areas between the locking beams. with the essentially parallel orientation of the opposing side walls of adjacent beams, the debris often remains within the slotted area unless physically removed by an outside force. Eventually the slot becomes filled and adversely affects the resilient nature of the locking beams. This situation is aggravated when the nut is used in a high temperature environment. Depending on the composition of the debris, high temperatures can cause the debris to harden and, as a result, force the beams to remain in an open position despite the removal of the bolt.

High temperatures often are not necessary to cause this aggravated condition as a sufficient accumulation of debris particles forced into the slotted area will cause the beams to remain open. Accordingly, the beams lose their locking ability because the debris does not allow them to return fully to their natural locking position.

It has been found that physically cleaning each slot in the nut after disassembly of the fastener is not a practical solution for the industry and replacing clogged nuts is not desirable from a cost standpoint. The present invention provides a beam construction and arrangement which is self-cleaning and thus answers this particular need of the industry.

SUMMARY OF THE INVENTION This invention is embodied in a locking beam nut having a plurality of circumferentially-spaced resilient locking beams that are- specially configured to prevent any accumulated debris from preventing a desired deflection of the beams. The beams project from a substantially rigid body and a circular opening extends completely through the body and the locking beams. The beams all taper inwardly such that the circular opening they define has a uniformly-decreasing diameter. Continuous threads of substantially uniform depth are defined in the aligned openings, for receiving an externally threaded member, the locking beams thereupon resiliently deflecting outwardly to lock the member in place.In accordance with the invention, the confronting side walls of adjacent beams are configured to diverge outwardly from each other, such that any debris located between them cannot inhibit inward deflection of the beams upon removal of the externally threaded member.

In a first embodiment, the side walls of each beam are configured to be substantially parallel with the beam's direction of inward deflection. Each beam therefore slides along any debris located in the adjacent slots. In a second embodiment, the side walls are configured such that inward deflection of the beams squeezes the debris outwardly. In a third embodiment, the side walls are configured such that inward deflection of the beams actually moves the beams away from any debris.

All three emhodiments can be modified to configure the beam side walls to include small portions parallel with the corresponding side wall portions of adjacent beams. These parallel side wall portions preferably extend no further than the depth of the threads in the beams' inner surfaces.

Other features and advantages of the present invention will be appreciated from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a locking beam nut embodying a first embodiment of the present invention.

FIG. 2 is a side elevational view of the locking beam nut shown in FIG. 1.

FIG. 3 is a top plan view of the locking beam nut shown in FIG. 2, with the locking beams being shown in their free, inward positions.

FIG. 4 is a side elevational view of the locking beam nut of FIG. 1, with a bolt locked therein.

FIG. 5 is a top plan view of the locking bean nut of FIG. 4 with the bolt not being shown, but with the locking beams nevertheless being shown in their locking, outward positions.

FIG. 6 is an enlarged view of a portion of the locking beam nut shown in FIG. 5.

FIG. 7 is an enlarged, fragmentary view of a portion of what is shown in FIG. 3, and de picting in phantom lines the relative positions of two beams when a bolt member is located within the nut.

FIG. 8 is a top plan view of one beam of the locking beam nut, depicting the different radii of curvature of the beam and the bolt.

FIG. 9 is a fragmentary top plan view similar to FIG. 7, but of a second embodiment of the invention, in which the confronting sidewalls of adjacent beams diverge from each other by a lesser amount.

FIG. 10 is a fragmentary top plan view similar to FIG. 7, but of a third embodiment of the invention, in which the confronting side walls of adjacent beams diverge from each other by a greater amount.

FIG. 11 is a fragmentary top plan view similar to FIG 7, but of a modified version of the first embodiment of the invention, in which small portions of the side walls of each beam are configured to be parallel with the corresponding side wall portions of adjacent beams.

DESCRIPTION OF THE PREFERRED EMBODI MENTS In the drawings like reference numerals are used to indicate identical ori like elements.

The present invention is an improvement in the construction and operation of known locking beam nuts or lock nuts, and in particular of the lock nut shown and described in U.S.

Patent No. 3,702,628. Lock nuts of this kind are generally of a one-piece construction. Each lock nut 20 has a nondeflectible or rigid body portion 21 and a plurality of locking segments or beams 22. Each beam is formed integrally with the body portion 21 and extends axially therefrom, as can be seen in FIGS. 1, 2, and 4, which illustrate a first embodiment of the invention. The body portion 21 has an internal axial opening extending completely through it, as shown in FIG. 3. The opening is threaded so as to receive the external threads of a bolt or like part of a fastener. The body portion 21 may also have a plurality of wrench flats 23 along its external surface.

The lock nut 20 is depicted to include six locking beams 22. It should be understood, however, that the invention is not limited to any specific number of locking beams.

Each locking beam 22 has an inner surface 24 and an opposite, outer surface 25, which is preferably flat. A top surface 26, which is typically flat, extends between the inner and outer surfaces 24 and 25 and defines a free end of the beam. The plurality of locking beams 22 are arranged circumferentially at one end of the body portion 21 such that the inner surfaces 24 define a circular opening that is threaded and in communication, i.e., axially aligned, with the opening of the body portion 21. The threads in the aligned open-ings of the body portion and the beams extend along the entire axial length of the aligned openings, and have a substantially uniform depth around their entire circumference.

Each locking beam 22 also has a first side wall 27 and a second side wall 28. Each of these side walls extends between the body portion 21 and the beam's inner, outer and top surfaces 24, 25, and 26, respectively.

Preferably, both side walls are smooth or flat.

In the first embodiment of the invention, depicted in FIG8. 1-8, the side walls 27 and 28 of each beam 22 are configured to be substantially perpendicular to the beam's outer surface 25. The confronting side walls of adjacent beams therefore diverge from each other, with increasing radial distance, forming an angle A. When the lock nut 20 includes six beams, as in the first embodiment, the side walls diverge at about a 60-degree angle.

To manufacture the lock nuts 20 embodying the present invention, known methods of machining and heading the nuts may be used to form the body portion 21 as well as the plurality of beams 22. It is believed no special tools or any modification of conventional machines is required to form the nuts as described in this application.

FIGS. 1-3 depict the lock nut 20 as it appears in a free state, prior to the insertion of an externally threaded member or bolt 80. It can be seen that the innermost portions of the beam side walls 27 and 28 are closely situated to adjacent beam side walls. As a bolt 30 is threaded into the lock nut and secured therein, as shown in FIG. 4, the beams deflect outwardly in the manner shown in FIG.

5. Upon removal of the bolt, each of the beams returns to its free state by flexing inwardly. The movement of the beams between a free state is schematically illustrated in FIG.

7. In the expanded or locking state, the beams are illustrated by phantom or broken lines.

The outward and inward deflecting movement of each beam 22 is along a radial axis substantially perpendicular to the beam's outer surface 25. This axis is substantially parallel with the side walls 27 and 28. Any debris located in the slot between the confronting side walls of adjacent beams therefore will not impede inward deflection of the beams, when the bolt 30 is removed. Accordingly, the lock nut configuration eliminates the problem of accumulated debris being compacted between the confronting side walls and inhibiting a return of the beams to their free, inward positions.

FIG. 8 is an enlarged plan view of a single beam 22 in association with the bolt 30. It will be observed that the radius of curvature of the beam's inner surface 24 is slightly greater than that of the bolt. This ensures that the surface and the bolt are tangent to each other only at a midpoint B of the beam, midway between the beam's side walls 27 and 28. The inner surface 24 and the bolt are spaced slightly away from each other at locations nearer the beam's side walls. The threads of the beam and bolt therefore cannot cut into each other and impede relative rotation.

FIG. 9 is a fragmentary top plan view similar to FIG. 7, but of a second embodiment of the invention, in which the side walls 27' and 28' of each beam 22' are configured to form a slightly acute angle with the outer surface 25'.

The specific angle is selected such that the confronting side walls of adjacent beams still diverge from each other, as indicated by the angle A', but by an amount less than that of the first embodiment (FIGS. 1-6). In this second embodiment, when the bolt (not shown) is removed, inward deflection of the beams causes their sidewalls to angle toward each other and, in doing so, squeeze outwardly any debris (not shown) located between them.

The outward force imparted by the inwardlydeflecting beams is indicated by the reference letter C. In the depicted embodiment, which includes six beams, the angle between each side wall and its corresponding outer surface is selected to be between a minimum of sixty degrees (60 ) and a maximum of ninety degrees (90").

FIG. 10 is a fragmentary top plan view similar to FIG8. 7 and 9, but of a third embodiment of the invention. In this third embodiment, the side walls 27" and 28" of each beam 22" are configured to form a slightly obtuse angle with the outer surface 25". The angle A" between the confronting side walls 27", 28" of adjacent beams is therefore greater than sixty degrees (60 ) in the depicted embodiment. Inward deflection of the side walls, upon removal of the bolt (not shown), therefore causes the side walls to move away from any debris (not shown) located between them. Such debris therefore offers substantially no resistance at all to such movement. Any obtuse angle between a side wall and the outer surface of each beam should satisfactorily eliminate the undesired effect of the debris.However, unduly increasing the angle above ninety degrees (90 ) could begin to affect adversely the resilience of the beams.

Any of the first three embodiments of Figs.

1-7, 9 and 10, respectively, can be modified such that small portions of the side walls 27 and 28 of each beam 22 are arranged to be substantially parallel with the corresponding side wall portions of adjacent beams. This modification is depicted in FIG. 11, with the parallel side wall portions being identified by the reference numerals 32 and 34. It should be noted that these parallel side wall portions extend over a relatively short distance, corresponding roughly to the depth of the threads in the inner surfaces 24 of the beams. The presence of the threads ensures that the side wall portions will provide only minimal resistance to inward deflection of the beams.

It should be appreciated from the foregoing description that the present invention provides a lock nut having deflectable beams that are specially configured to prevent debris located in slots between the beams from inhibiting inward deflection of the beams from a locking position to a free position. In all of the disclosed embodiments, the confronting side walls of adjacent beams are configured to diverge outwardly away from each other. The debris therefore either has substantially no effect at all on inward deflection of the beams or is squeezed radially outward in response to such inward deflection.

Although the invention has been described in detaii with reference to the presently preferred embodiments, those of ordinary skill in the art will appreciate that various modifications can be made without departing from the invention. Accordingly, the invention is defined only by the following claims.

Claims

1. A locking beam nut adapted to receive an externally-threaded member, the locking beam nut comprising: a substantially rigid body having a circular opening extending through it; and a plurality of resilient, circumferentiallyspaced locking beams projecting from the rigid body and having inner surfaces that define a circular opening aligned with the circular opening in the body, each of the locking beams tapering radially inwardly such that the circular opening defined by the plurality of locking beams has a uniformly-decreasing diameter, wherein the aligned circular openings defined by the respective rigid body and plurality of locking beams contain threads along their entire axial length for receiving an externally threaded member, the locking beams resiliently deflecting radially outwardly to lock the member in place, wherein the plurality of locking beams each have side walls arranged in spaced, confronting relationship with the side walls of circumferentially-adjacent locking beams, and wherein the plurality of locking beams are configured such that substantially the entire confronting side walls of adjacent beams diverge from each other, with increasing radial distance, such that any debris located in the space between the side walls does not inhibit a resilient return of the beams to their undeflected locations when the externallythreaded member is removed from the locking beam nut.

2. A locking beam nut as defined in Claim 1, wherein the side walls of each of the locking.beams are substantially planar and substantially parallel with each other and with the direction of the beam's radial deflection.

3. A locking beam nut as defined in Clairri 1, wherein the side walls of each of the plu rality of locking beams are substantially planar and converge toward each other with increasing radial distance.

4. A locking beam nut as defined in Claim 1, wherein the plurality of locking beams include six equal-sized, uniformly-spaced locking beams.

5. A locking beam nut as defined in Claim 1, wherein the rigid body and the plurality of locking beams are all integral with each other.

6. A locking beam nut as defined in Claim 1, wherein the side walls of each locking beam include portions configured to be substantially parallel with corresponding portions of the confronting side walls of adjacent beams, the portions extending radially a distance substantially equal to the depth of the beam's threads.

7. A locking beam nut as defined in Claim 1, wherein the inner surfaces of the plurality of locking beams all have a radius of curvature greater than that of the circular opening in the rigid body and that of the externally-threaded member, such that when the locking beam nut receives the externally-threaded member the member is tangent with each locking beam only at a midpoint between its two side walls, thereby reducing resistance to rotation of the member relative to the locking beam nut.

8. A locking beam nut adapted to receive an externally-threaded member) the locking beam nut comprising: a substantially rigid body having a circular opening extending through it; and a plurality of resilient, circumferentiallyspaced locking beams integral with the rigid body and projecting outwardly from one end thereof, the locking beams having inner surfaces that define a circular opening aligned with the circular opening in the body, each of the locking beams tapering radially inwardly such that the circular opening defined by the plurality of locking beams has a uniformly-decreasing diameter, wherein the aligned circular openings defined by the respective rigid body and plurality of locking beams contain threads along their entire axial length for receiving an externally threaded member, the locking beams resiliently deflecting radially outwardly to lock the member in place, wherein the plurality of locking beams each have side walls arranged in spaced, confronting relationship with the side walls of circumferentially-adjacent locking beams, wherein the inner surfaces of the plurality of locking beams all have a radius of curvature greater than that of the circular opening in the rigid body and that of the externally-threaded member, such that when the lock nut receives the externally-threaded member the member is tangent with each locking beam only at a midpoint between its two side walls, thereby reducing resistance to rotation of the member relative to the locking beam nut, and wherein the plurality of locking beams are configured such that substantially the entire confronting side walls of adjacent beams diverge from each other, with increasing radial distance, such that any debris located in the space between the side walls does not inhibit a'resilient return of the beams to their undeflected locations when the externallythreaded member is removed from the locking beam nut.

9. A locking beam nut as defined in Claim 8, wherein the side walls of each of the locking beams are substantially planar and substantially parallel with each other and with the direction of the beam's radial deflection.

10. A locking beam nut as defined in Claim 8, wherein the side walls of each of the plurality of locking beams are substantially planar and converge toward each other with increasing radial distance.

11. A locking beam nut as defined in Claim 8, wherein the plurality of locking beams include six equal-sized, uniformly-spaced locking beams.

12. A locking beam nut as defined in Claim 8, wherein the side walls of each locking beam include portions configured to be substantially parallel with corresponding portions of the confronting side walls of adjacent beams, the portions extending radially a distance substantially equal to the depth of the beam's threads.

13. A locking beam nut, substantially as hereinbefore described with reference to the accompanying drawings.