US3602074A

US3602074A - Adjustable, self-aligning joint for pliers, shears and the like

Info

Publication number: US3602074A
Application number: US734652A
Authority: US
Inventors: Eugene F Smith
Original assignee: Rocky Mountain Dental Products Co
Current assignee: Rocky Mountain Dental Products Co
Priority date: 1968-06-05
Filing date: 1968-06-05
Publication date: 1971-08-31
Anticipated expiration: 1988-08-31

Abstract

A tool including a pair of members mounted for relative rotation with respect to each other about a pivot column in which said pivot column is nonfrictionally, rigidly mounted with respect to one of said members and rotatably mounted with respect to the other of said members and in which said pivot column and said members include means for maintaining one of said members in a predetermined pivotal relationship with the other said member during operation thereof.

Description

United States Patent Inventor Eugene 1F. Smith Denver, Colo.

June 5, 1968 Aug. 31, 1971 Rocky Mountain Dental Products Co.

Denver, Colo.

Appl. No. Filed Patented Assignee ADJUSTABLE, SELF-ALIGNING JOINT FOR PLIERS, SHEARS AND THE LIKE 2 Claims, 11 Drawing Figs.

us. c1 81/416, 30/266, 287/101 11111. or B25b 7/06, Fl6c 1 1/00 Field ofSearch 81/416,

[56] References Cited UNITED STATES PATENTS 3,289,296 12/1966 Hedstrom et a1. 287/101 X 3,355,200 11/1967 Storch 287/101 2,596,767 5/1952 Erickson 30/266 3,331,132 7/1967 Miles etal. 30/266 Primary Examiner-R0bert C. Riordon Assistant Examiner-Roscoe V. Parker, Jr. All0rney-Sheridan and Ross ABSTRACT: A tool including a pair of members mounted for relative rotation with respect to each other about a pivot column in which said pivot column is nonfrictionally, rigidly mounted with respect to one of said members and rotatably mounted with respect to the other of said members and in which said pivot column and said members include means for maintaining one of said members in a predetermined pivotal relationship with the other said member during operation thereof.

PATEHTEH was] I971 SHEEI 1 BF 2 INVENTOR EUGENE E SMITH ATTORNEYS amz 'm I ADJUSTABLE, SELF-ALIGNING JOINT FOR PLIERS, SHEARS AND THE LIKE BACKGROUND OF THE INVENTION Heretofore, many joints have been proposed for tools and the like including pivotally mounted members. However, none of such tools has provided a joint having an adjustable operating torque which will remain substantially unchanged even though one of the members has been pivotally operated with respect to the other one a large number of times. For example, it has been found that the operating torque for joints of tools of this type changes, at least gradually, with each pivotal movement of one of the members relative to the other one. Further, it has been found desirable not only to establish and maintain a predetermined operating torque for a tool of this type but also at the same time to insure that the pivotally mounted members are always disposed with respect to each other in a predetermined pivotal relationship. This latter item is particularly important for pliers used to handle or position small items such as arch wires and the like involved in the field of orthodontia and also for precision'shears.

SUMMARY OF THE INVENTION This invention relates generally to a joint for a tool including a pair of pivotally mounted members and more specifically to a joint for a tool such as pliers, shears and the like in which said pivotally mounted members rotate about a pivot column which is nonfrictionally rigidized with respect to one of said members but mounted for pivotal movement with respect to the other said member, and said pivotally mounted members and said pivot column including means for maintaining one of said members in a predetermined pivotal relationship with the other said member during operation thereof.

It has been found, however, that a joint for a tool having a pair of pivotally mounted members may be provided which operates continuously at a predetermined torque level by mounting said members about a pivot column which is nonfrictionally rigidized with respect to one of said members but mounted for pivotal movement with respect to the other of said members. Further, a precise, predetermined pivotal relationship between said members may be continuously maintained through the use of a pivot column having a pair of conically shaped portions formed on the surfaces thereof in combination with conically shaped bore portions formed in said pivotal members wherein the conically shaped portions formed on said pivot column are disposed in mating contact with the conically shaped bore portions formed in said members. Through the use of the joint structure of this invention, the amount of torque is not only infinitely adjustable butif the torque level has changed for any reason whatsoever, it is a simple matter to adjust the joint structure of this invention and reset the torque to the desired level without disassembling the joint structure. Additionally, the torque is substantially constant for any open or closed position of the members involved.

Moreover, due to the large bearing areas provided, a joint structure as described herein has an increased life since the force holding the parts together is distributed over a larger wear area. I

Accordingly, one of the principal objects of this invention is to provide an improved joint for a tool including a pair of members mounted for relative rotation with respect to each other.

Another object of this invention is to provide a joint for a tionship of one of said members with respect to the other one is precisely maintained over a large number of pivotal operation of said members.

Another object of this invention is to provide atool includ ing a pair of members mounted for relative rotation with respect to each other about an axis and abutting in a plane perpendicular to said axis, the improvement being the tool comprising in combination a bore formed in each of said members, each of said bores havinga longitudinal axis concentrically disposed with respect to the aforesaid axis, each of said bores having a portion forming a conically shaped bearing seat; and a pivot column, said pivot column being nonfrictionally rigidized with respect to one of said members and mounted for relative rotation with respect to the other of said members, said pivot column comprising a screw portion and a nut portion, said screw portion having a conically shaped portion formed thereon and disposed in mating contact with the conically shaped bearing seat formed on. one of said members, and said nut portion having a conically shaped portion formed thereon and disposed in mating contact with the conically shaped bearing seat formed in the other of said members.

DESCRIPTION OF THE DRAWINGS.

The foregoing and other objects and advantages of this invention will become apparent from the specification and accompanying drawings wherein:

FIG. l is a plan view of a plier-type tool incorporating the joint constructed in accordance with the subject invention;

FIG. 2 is a plan view of a portion of one of the members shown in FIG. ll;

FIG. 3 is a bottom plan view of the member shown in FIG. 2;

FIG. 4 is a plan view of a portion of the other one of said members shown in FIG. I;

FIG. 5 is a bottom plan view of the member shown in FIG. 4;

FIG. 6 is a partial cross-sectional view taken along line 66 in FIG. 1;

FIG. 7 is an exploded view of a pivot column used in a tool constructed in accordance with the subject invention;

FIG. 8 is a plan view of the nut portion of the pivot column shown in FIG. 7;

FIG. 9 is a bottom plan view of the nut portion shown in FIG. 3;

FIG. 10 is a bottom plan view of the screw portion of the pivot column shown in FIG. 7;

FIG. l I is a view similar to that shown in FIG. 6 showing an additional embodiment of a joint constructed in accordance with the subject invention; and

FIG. 12 is a perspective view of a hollow, frustoconically shaped bushing shown in FIG. 11.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, in FIGS. 1-10 is shown one embodiment of a tool 20 incorporating a joint constructed in accordance with the subject invention. The tool 20, which is depicted as a pair of pliers, includes a pair of

members

22 and 2 mounted for relative rotation with respect to each other about an axis 26, see FIG. 6, and abutting in a plane perpendicular to said axis 26. Each of the members 22 and 2d has a

bore

28 and 30, respectively, formed therein. Each of said bores 2b and 30 has a longitudinal. axis concentrically disposed with respect to the aforesaid axis 26. Each of said

bores

28 and 30 also has a portion forming a conically shaped

bearing seat

32 and 34, respectively.

The tool 20 also includes a pivot column 36 which is nonfrictionally rigidized with respect to one of said members, such as member 22, and mounted for relative rotation with respect to the other of said members, such as member 24. The pivot column 36 comprises a screw portion 38 and a nut portion 40. The screw portion 38 has a conically shaped portion 42 formed thereon which is disposed in mating contact with the conically shaped bearing seat 32 of bore 28. The nut portion 40 of said pivot column 36 has a conically shapedportion M formed thereon which is disposed in mating contact'with a conically shaped bearing seat 34 of bore 30. The pivot column 36 also includes a boss means such as the axially extending boss portions 46 formed on one end of the nut portion 40, Each of said boss portions 46 are disposed within a cortorque that will be encountered in operating or pivoting one of responding recess portion 48 formed in the upper surface of member 22 as shown in FIGS. 2 and 6. The pivot column 36 also includes a tool-receiving means such as the slot or recess 50 formed in the head of the screw portion 38.

The assembly of the tool shown in FIGS. 1-10 is now described. For a right-handed person, the member 24 is preferably held in the left hand in the position indicated in FIG. 4. The nut portion 40 is then inserted within the bore of member 24. The forefinger of the left hand is then positioned above the assembled nut portion and member 24. The assembled nut portion and member 24 are inverted and member 22, which is held in the right hand in the position indicated in FIG. 3, is then placed in overlying relationship with respect to the assembled nut portion 40 and member 24 until the bores of said members are aligned and theboss portions 46 of the. nut portion 40 are disposed within the recess portions 48 formed in member 22. Next, the screw portion 38 is inserted within the bore 28 of member 22 and through the use of a suitable tool (not shown) such as a screwdriver, the screw portion 38 is threaded into the nut portion 40. The amount of such threading depends upon the degree of force desired to hold the

mating surfaces

52 and 54, respectively, in contacting engagement with each other. The degree of force with which

members

22 and 24 are held together determines the amount of torque required to operate or pivot one of the members relative to the other member.

It will be readily appreciated that as a result of the boss portions 46 being disposed within the recess portions 48 there will be no transfer of friction between member 24, which is mounted for relative rotation with respect to the pivot column 36, and the pivot column 36 during operation and use of the tool that would result in the nut portion tightening or loosening with respect to the screw portion. This unique advantage is achieved by nonfrictionally rigidizing the pivot column 36 with respect to member 24. In this connection, it will be understood that mere reliance upon the frictional forces generated by the mating contact between the threaded parts of the nut 40 and the screw portion 38 are entirely inadequate to achieve the desirable benefit obtained herein,

The use of the conically shaped bearing

seats

32 and 34 formed, respectively, in the

bores

28 and 30 in combination with the conically shaped portions formed on the pivot column are highly beneficial in maintaining a predetermined pivotal relationship between the

members

22 and 24. Where exacting positioning work or tensioning of a wire or the like must be performed by a too] similar to that described herein, it

' is necessary that the jaws of

members

22 and 24 maintain a predetermined pivotal relationship with respect to each other for any of the various angular positions of one member with respect to the other one otherwise it will not be possible to grip or hold an object with the proper amount of force to permit positioning or tensioning in the manner desired. It is recognized that this feature, in and of itself, is not new due to the disclosure contained in US. Pat. No. 2,596,767. However, this feature in combination with the nonfrictional rigidizing of a pivot column with respect to one of a pair of pivotally mounted members while at the same time permitting said pivot column to rotate with respect to the other of said pivotally mounted members produces unique and beneficial results heretofore unobtainable.

The tool 20' shown in FIG. 11 is similar in every respect to the tool shown in FIG. 6 except for the incorporation of a generally annular frustoconically shaped bushing 56, see also FIG. 12, which is disposed intermediate the nut portion 40' of pivot column 36' and member 24'. The bushing 56 is formed from a material having a low coefficient of friction such as tetrafluoroethylene. The purpose for using the bushing 56 is to control, at least in part, the maximum amount of operating the members relative to the other of said members. v

In view of the foregoing, it will be readily appreciated that a tool having a joint constructed in accordance with the invention described herein is easily adjustable for wear or for feel" for any degree of tightness. Further, such adjustability may be achieved through the use of a single tool since the nut portion is nonfrictionally rigidized with respect to one of said members. In addition, it will also be understood that the turning resistance of the pivot is constant through the full arc of movement; adjustment for the degree of tightness with which the members are held together can be made without disassembly of the tool; no change of alignment of parts occurs as a result 'of any such adjustment; the nut portion of the pivot column will neither loosen nor tighten from pivotal operation of the members; the joint is durable in construction; the tool is easily assembled and disassembled in a matter of seconds; and all parts are autoclavable or will withstand sterilization.

It is to be understood that this invention is not limited to the exact embodiments of the devices shown, which are merely by way of illustration and not limitation, as various other forms and modifications will be apparent to those skilled in the art; e.g. the tool-receiving means can be formed upon the nut portion of the pivot column and the boss means may be formed upon the screw portion of the pivot column, and it is therefore intended that the appended claims cover all such changes and modifications.

I claim:

1. A controllable torque, pivotal joint suitable for use in a tool formed of a pair of longitudinal members that include handles at one end and tool elements at the other end, the pair of longitudinal members being pivotably joined intermediate their ends, said controllable torque, pivotal joint comprising:

A first frustoconically shaped bore, including at least one internal outwardly projecting recess, formed in one of said pair of longitudinal members;

a second frustoconically shaped bore formed in the other of said pair of longitudinal members, the longitudinal axes of said first and second frustoconically shaped bores being concentrically disposed with respect to one another, said first and second frustoconically shaped bores being formed so that their smaller ends face one another when said pair of longitudinal members are pivotably joined;

a frustoconically shaped screw mounted in said first frustoconically shaped bore, said frustoconically shaped screw including an undercut threaded stud formed along the longitudinal axis of said first frustoconically shaped bore and projecting into said second frustoconically shaped bore along the longitudinal axis thereof; and,

a frustoconically shaped nut mounted in said second frustoconically shaped bore for rotation with respect to said second frustoconically shaped bore, said frustoconically shaped nut including at least one boss formed so as to fit into said at least one outwardly projecting recess in said first frustoconically shaped bore so as to prevent rotational movement of said frustoconically shaped nut with respect to said first frustoconically shaped bore, said frustoconically shaped nut including a threaded aperture formed along the longitudinal axis of said second frustoconically shaped bore, the threaded stud portion of said frustoconically shaped screw being screwed into said threaded aperture in said frustoconically shaped nut so as to maintain said pair of longitudinal members in pivotal relation with respect to one another, the surface of said frustoconically shaped nut facing toward said first frustoconically shaped bore and the frustoconically shaped portion of said frustoconically shaped screw being separated from said first frustoconically shaped bore and the frustoconically shaped portion of said frustoconically shaped screw so that the only contacting surface between said frustoconically shaped nut and said frustoconically shaped screw is the threaded region where said frustoconically shaped screw is screwed into said frustoconically shaped nut whereby the torque at said pivotal joint is controlled by the amount of thread of said frustoconically shaped screw that is screwed into saidthreaded aperture in said frustoconically shaped nut. 2. A pivotal joint suitable for use in a tool as claimed in

Claims

1. A controllable torque, pivotal joint suitable for use in a tool formed of a pair of longitudinal members that include handles at one end and tool elements at the other end, the pair of longitudinal members being pivotably joined intermediate their ends, said controllable torque, pivotal joint comprising: A first frustoconically shaped bore, including at least one internal outwardly projecting recess, formed in one of said pair of longitudinal members; a second frustoconically shaped bore formed in the other of said pair of longitudinal members, the longitudinal axes of said first and second frustoconically shaped bores being concentrically disposed with respect to one another, said first and second frustoconically shaped bores being formed so that their smaller ends face one another when said pair of longitudinal members are pivotably joined; a frustoconically shaped screw mounted in said first frustoconically shaped bore, said frustoconically shaped screw including an undercut threaded stud formed along the longitudinal axis of said first frustoconically shaped bore and projecting into said second frustoconically shaped bore along the longitudinal axis thereof; and, a frustoConically shaped nut mounted in said second frustoconically shaped bore for rotation with respect to said second frustoconically shaped bore, said frustoconically shaped nut including at least one boss formed so as to fit into said at least one outwardly projecting recess in said first frustoconically shaped bore so as to prevent rotational movement of said frustoconically shaped nut with respect to said first frustoconically shaped bore, said frustoconically shaped nut including a threaded aperture formed along the longitudinal axis of said second frustoconically shaped bore, the threaded stud portion of said frustoconically shaped screw being screwed into said threaded aperture in said frustoconically shaped nut so as to maintain said pair of longitudinal members in pivotal relation with respect to one another, the surface of said frustoconically shaped nut facing toward said first frustoconically shaped bore and the frustoconically shaped portion of said frustoconically shaped screw being separated from said first frustoconically shaped bore and the frustoconically shaped portion of said frustoconically shaped screw so that the only contacting surface between said frustoconically shaped nut and said frustoconically shaped screw is the threaded region where said frustoconically shaped screw is screwed into said frustoconically shaped nut whereby the torque at said pivotal joint is controlled by the amount of thread of said frustoconically shaped screw that is screwed into said threaded aperture in said frustoconically shaped nut.

2. A pivotal joint suitable for use in a tool as claimed in claim 1 including a hollow, frustoconically shaped bushing formed from a material having a low coefficient of friction, said bushing being disposed between said frustoconically shaped nut and said second frustoconically shaped bore.