US3818784A

US3818784A - Changeable tip tweezers and the like

Info

Publication number: US3818784A
Application number: US00320817A
Authority: US
Inventors: Clure E Mc
Original assignee: Scient Components Inc
Current assignee: Scientific Components Corp
Priority date: 1973-01-03
Filing date: 1973-01-03
Publication date: 1974-06-25
Anticipated expiration: 1991-06-25
Also published as: GB1401570A; CA995935A; CH578916A5

Abstract

Changeable tip tweezers formed of a handle portion having a pair of resilient arms extending in a V-shaped path from a heel end and terminating in outwardly opening channel recesses, receiving substantially wedge shaped mounting formations on the rear ends of changeable tips. The surfaces of the mounting formations are engaged and positioned by confronting surfaces of the channel recesses to precisely aline the tips, and enlarged circular nut members of larger diameter than the vertical width of the tweezers hold the tips on the handle portion and provide rest supports and finger discs.

Description

United States Patent [191 McClure June 25, 1974 CHANGEABLE TIP TWEEZERS AND THE LIKE [75] Inventor: Edgar M. McClure, Roanake, Va. [73] Assignee: Scientific Components Inc.,

Roanoke, Va.

[22] Filed: Jan. 3, 1973 [21] Appl. No.: 320,817

[52] 11.8. C1. 81/43 [51] Int. Cl B25b 9/02 [58] Field of Search 81/43; 128/354; 294/99 [56] References Cited UNITED STATES PATENTS 1,758,490 5/1930 Aderer 81/43 2,764,905 10/1956 Thoms 81/43 2,833,239 5/1958 Larsten, 81/43 X FOREIGN PATENTS OR APPLICATIONS 348,130 9/1960 Switzerland 81/43 769,917 3/1957 Great Britain 128/354 561,890 10/1932 Germany ..8l/43 Primary Examiner-Othell M. Simpson Assistant ExaminerRoscoe V. Parker Attorney, Agent, or Firm-Mason, Fenwick & Lawrence [57] ABSTRACT Changeable tip tweezers formed of a handle portion having a pair of resilient arms extending in a V-shaped path from a heel end and terminating in outwardly opening channel recesses, receiving substantially wedge shaped mounting formations on the rear ends of changeable tips. The surfaces of the mounting formations are engaged and positioned by confronting surfaces of the channel recesses to precisely aline the tips, and enlarged circular nut members of larger diameter than the vertical width of the tweezers hold the tips on the handle portion and provide rest supports and finger discs.

9 Claims, 6 Drawing Figures CHANGEABLE TIP TWEEZERS AND THE LIKE BACKGROUND AND OBJECTS OF THE INVENTION The present invention relates to improvements in tweezer type instruments for facilitating picking up, handling, and/or inspection of small articles, and more particularly to precision tweezers for use in handling tiny components, wherein the jaw portions of the tweezers forming the tips or points are readily removable from the arms of the tweezers for repair, sharpening, or replacement with like or different shaped tips and wherein the changeable tweezer tips are accurately held so that precise point match is achieved at the outer ends of the tips.

In the manufacture of many articles, components which are required to be inspected, or picked up and handled by workmen are so small that greater precision in the construction and operating characteristics of the tweezers are required than are available in ordinary commercial tweezers. For example, in the electronic industry, tweezers or similar instruments are required for handling discs such as the germanium and silicone wafers without scratching the semi-conductor wafers, and which permit easy pick-up and safe gripping of the semi-conductor wafers. Many of the miniature, or micro-miniature electronic parts are highly fragile, and expensive or costly losses are sometimes suffered from accidental dropping or release of such components. Most frequently, the accidental dropping of the components being handled by tweezers occurs because of end flexing of the tweezer points, wherein the outermost ends of the tweezer points or tips become separated somewhat from each other when the tweezer handles are overstr'essed toward each other and engagement of portions of the tweezer tips spaced about a half-inch or so back of the ends of the points produces a bowing of the tweezer points or tips distorting the outermost ends away from each other. This distortion or end flexing may produce sufficient separation to release the item being held between the tweezer points. Also this characteristic of many tweezers of end flexing makes it very difficult to pick up extremely thin items such as paper, because the outermost ends of the tweezer tips or points may be distorted away from each other a greater distance than the thickness of the paper or thin sheet material to be grasped.

Also, in handling tiny watch parts or jewelry components, and for manipulating such tiny parts, as in straightening or bending hair springs for watches, the tweezers must have very slender points, which are delicate and easily dulled, and are subjected to breakage if extreme caution is not exercised when the tweezers are laid down on the work bench. In conventional tweezers, the points are made integral with the arms of the tweezers,'and if dulled or broken, can be properly resharpened only by someone highly skilled in that procedure and at the expense of considerable time and cost. Provision of removable tips or points facilitates removal and installation of a new set of tips by the user with minimum expense and loss of time. However, it has been difficult to insure that tweezer tips which are removably secured to handles, when being replaced for any reason, maintain such accurate alinement with the handle and preserve their original position relative to their companion tips that precise point match is maintained.

Also, manufacturing operations involving handling or inspection of miniature components frequently require a number of different types of tweezer tips for effective access to and handling of the miniature components. in some cases, long very pointed tips are required, with flat confronting surfaces, while in other situations, angled or curved tips of various configurations, or tips with concave or convex ends may be required for particular applications. Economies in manufacture of fine precision tweezers and components therefor can be achieved where such situations exist, by supplying a number of different configurations of precision manufactured tip portions for tweezers in various shapes and configurations, without having to manufacture an entire pair of tweezers for each tip shape. Thus standardized handles with a number of different tip configurations permits economies to be realized in the manufacture of the tip portions only.

Also, conventional tweezers suffer the disadvantage of tending to skew when pressed together, so that the end portions of the points or tips do not precisely match up but become shifted out of precise alinement and cross each other slightly. To avoid this problem, as well as the problem of end flexing, precision tweezers for industrial handling of miniature components and for medical uses in other precision applications are generally much heavier on the end portions of the points and have required precision grinding to file them down to exactly true positions and configurations. This can be more effectively and economically achieved where the tweezer tips are formed as separate components which are later assembled to the arms of the tweezer handle portions, so that only the tip portions need to be shaped and processed to produce the desired precision configuration and surface characteristics.

An object of the present invention, therefore, is the provision of a novel tweezer construction having changeable tips or points separably connected to the ends of the arms of the tweezer handle portions, wherein the tips are coupled to the tweezer handle arms by a novel construction insuring precise alinement of the changeable tips with each other to achieve exact point match, and wherein the tweezer tips may be separably manufactured and processed in a way to minimize end flexing or skewing of the tweezer tips during use.

Another object of the present invention is the provision of a novel changeable tip tweezer construction as described in the immediately preceding paragraph, wherein finger discs form removable portions of the coupling structure for mounting the changeable tweezer tips on the arms of the tweezer handle portion, facilitating supporting of the tweezers in a manner protecting their tips when the tweezers are at rest on a work bench or the like and also inducing users to hold the tweezers in a consistent position which facilitates always picking them up and positioning them in a particular way.

Other objects, advantages and capabilities of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings illustrating preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a perspective view of one embodiment of changeable tip tweezers constructed in accordance with the present invention, with one of the tweezer tips or points and the coupling disc therefor shown in exploded relation;

FIG. 2 is a side elevation view of the changeable tip tweezers;

FIG. 3 is a top plan view of the changeable tip tweezers;

FIG. 4 is a vertical transverse section view, taken along the line 4-4 of FIG. 2;

FIG. 5 is a fragmentary horizontal longitudinal section view through the coupling mechanism associated with one arm of the tweezers, taken along the line 55 of FIG. 2; and

FIG. 6 is a perspective view similar to FIG. 1, but having tweezer tips which are of a different form from those illustrated in FIG. 1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the drawing, wherein like reference characters designate corresponding parts throughout the several figures, and particularly to the embodiment of FIGS. I through 5, the tweezers of the present invention are indicated generally by the reference character 10 and include a handle portion 12 of customary configuration having a pair of resilient arms 14 that may be substantially identical, having the butt ends or heel portions joined together in the conventional manner to provide a heel end 16. The two arms 14 diverge outwardly from the heel end portion 16 in a shallow V- shaped configuration, when viewed in top plan, and terminate in end formations I8 specially shaped and formed to facilitate removable mounting of tweezer tips 20 thereon. The elements herein referred to as tips or tweezer tips are also customarily referred to in the trade as points or jaw portions of tweezers. In the embodiment illustrated in FIGS. 1 to 5, the tweezer tips 20 are straight, tapered, sharpened or pointed tips 20 having flat inner faces of triangular profile terminating in sharply pointed outer ends 24 and having mounting portions 26 at the base ends thereof which are substantially wedge shaped formations of rectangular lateral profile defining outer faces 26a which converge rearwardly or toward the heel end of the tweezers relative to the rearwardly diverging, opposed confronting faces 22 of the tip portions and lie in substantially parallel planes when the tweezer arms occupy their normal, unstressed diverging positions. The rearward mounting portions 26 of the tweezer tips 20 are each provided with a single aperture 26b extending therethrough along an axis perpendicular to the plane of the outer face 26a.

To accurately position the tips 20 exactly in their properly alined relation with the opposing confronting faces 22 converging forwardly in the proper planes or paths so that they meet at the outer ends 24 with precise point match, the end formations 18 of the handle portions 12 are formed with broached channel shaped kerfs or recesses 28 which open outwardly through the outer faces of the associated handle arms 14 and open through the forward ends of the respective handles, as best shown in FIG. I. The channel shaped kerfs or recesses 28 are shaped to define confronting channel sides 28a of triangular configuration accurately conforming to the vertical spacing between the upper and lower parallel surface portions 26c of the rectangular wedge shaped mounting portions 26, while the base wall 28b of each of the kerfs or recesses 28 is rectangular in lateral profile corresponding exactly to the portion of the opposing confronting faces 22 of the tips to be nested in the channel shaped recesses. The base walls 28b of the channel shaped recesses 28 lie in forwardly converging planes which conform exactly to the desired planes in which the opposing confronting faces 22 of the tips are to lie, so that exact location and disposition of the tips 20 is achieved by the nesting of the mounting portions 26 in the channel shaped recesses 28. The proper convergence of the tip members and the proper axial alinement of the tip members with the desired high degree of precision is attained in a very accurate, but inexpensive way by broaching the end portions of the handle arms 14 with the handle held in a jig which clamps the handle arms 14 securely at the proper normal angular position, preferably with the handle arms diverging upwardly in a vertical position, and relatively moving twin broaches downwardly from above the jig mounted handle portion to remove the necessary material from the upper end portions of the jig supported handle arms as the broaches move relatively downwardly and thereby precisely form the wedge shaped channel 28 in the outwardly facing portion of each of the two handle arms 14.

The tips 20 are held in the channel recesses 28 in the handle arms 14 by threaded screws or studs 30 fixed in a conventional manner to the mounting portions 26 of the handle arms 14, which extend through the apertures 26b in the mounting portions 26 of the respective tips 20 and are threaded into threaded openings 32a in slightly concave disc members 32 of considerably larger diameter than the maximum vertical dimension of the handle arms when viewed in side elevation in the horizontal position, as shown in FIG. 2. The disc members 32 form convenient finger discs for engagement between the pads of two fingers of the users hand, for example the thumb and index finger, for manipulation of the tweezers so as to bring the outer ends of the tips or points together or separate them, while the heel portion of the handle 12 rests against the base of the little finger in a crook formed by the curled little finger of the user's hand. To this end, the large disc formations 32b of the disc members 32 are outwardly concave to present inwardly dished circular surfaces to the users fingers, while smaller diameter hub portions 32c extend inwardly concentric with the threaded openings 32a and terminate in flat cylindrical surfaces to bear against the outer faces 26a of the mounting portions of the tips and tightly clamp the tips in the channel recesses 28. Also, the larger diameter disc fonnations on the disc members 32b, which have knurled peripheries to facilitate rotation of these disc members, serve as a pair of convenient supporting formations to form with the heel end portion 16 the three contact portions of a threepoint supporting contact for the tweezers on a work bench or horizontal supporting surface to maintain the precisely ground end portions of the tip out of contact with the work surface and minimize possibility of damage to the working end portions of the tips.

In the illustrated example, the threaded screws 30 are fonned with rectangular, slightly enlarged head portions 30a seated in confonning recesses in the confronting faces 22 of the handle, with the heads either loosely fitted in the recesses or permanently fastened therein as by spot welding, or press fitting, or any other desired, known fastening technique.

FIG. 6 illustrates a modified version of the tweezers, wherein the handle portion 12 is the same as in the preceding embodiment and includes the pair of diverging, resilient arms 14 joined together at the heel or butt end 16 and having the channel shaped recesses 28 in the front ends thereof formed in the same manner as in the previously described embodiment. The tips or jaw members, however, in this embodiment are angled tips or angled points, indicated generally by the reference character 40, having opposing confronting faces 42-and angled outer end portions 44 which are shaped to define sharp points at the outer ends. The mounting portion 46 of this embodiment, however, is a stepped, twostage mounting formation providing a first mounting stage 48 nearer the rear end of each tip 40 having a flat outer face 480 which extends in a plane rearwardly converging somewhat relative to the plane of the forwardly convergent faces 42 and is in fact parallel to the medial center plane of the tweezers, and has an aperture 48b for receiving the mounting screw or stud 30 and has upper and lower parallel surfaces 48c spaced apart exactly the same distance as the channel sides 28a to engage the latter and accurately position the associated tweezer tip 40 relative to the arms of the handle portion. The second mounting stage is indicated at 50 and is spaced forwardly from the rear end of the associated tweezer tip and includes a flat outer face 500 paralleling the medial longitudinal vertical plane of the tweezers, and aperture 50b of the same size as the aperture 48b, and the upper and lower edges of the mounting stage 50 are extensions of the parallel upper and lower surfaces 480. The second stages 50 of the two tweezer tips 40 are so located that when the mounting screws 30 are inserted through the apertures 50b, the tweezer tips are shortened to a selected dimension, rendering the tweezers with the tips 40 capable of serving as long angled point tweezers or short angled point tweezers. as desired by the user, by merely selecting which of the mounting stages 48, 50 are to be nested in the channel recesses 28 of the tweezer arms.

it will be appreciated that the changeable tip tweezer construction herein described provides a convenient and economical precision coupling or mount for the tweezer tips whereby tips of various shapes and sizes can be interchangably mounted on the tweezer arms to fit various use requirements. Furthermore, the tips, being detachable from the handle portions, can be readily made from different. more expensive material than the handle portion, and can be precision processed more conveniently as separate tip portions in appropriate jigs and processing machines to produce precision tips much more economically than if they were integrally joined with the flexible handle portions of the tweezers. The mounting channel recesses in the handle portion of the tip are precisely formed preferably by broaching at such angles, when the handle portion is held in a jig, to define very accurate channels having base walls which are disposed in forwardly converging planes disposed at the proper angle to establish exactly the desired normal angle of convergence of the two tip members and which precisely interfit with the mounting portions at the rearmost ends of the tip members so as to exactly aline the tip members with each other and resist skewing or similar distortions of the tweezer tips. The weight of the heel portion of the tweezer handle and the length of the handle is such that the tweezers are normally readily supported on a work bench or tool tray or other horizontal supporting surface with the heel end 16 and the lowermost portion of the periphery of the two finger discs 32 forming a three-point contact support for the tweezers, with the tip portions extending outwardly at a slight angle above the horizontal and out of contact with the supporting surface. The tweezers are conveniently grasped by the user by merely grasping the finger discs 32 between two fingers of the users hand, for example the thumb and index finger, with the pads of the fingers engaging the slightly concave dished circular outer surfaces of the finger discs 32 and with the heel portion 16 of the handle engaged by the little finger of the user, insuring highly effective and secure control of the tweezers by the user. Thus time losses from mishandling or fumbling of miniature components to be grasped by the tweezers, as well as costly losses from dropping of specially cleaned or fragile items being handled, is minimized by this tweezer construction.

It will be appreciated that a wide variety of tweezer tip configurations of many sizes, shapes, and types can be removably mounted on the tweezer handle by the construction of the present invention, as well as various designs of cutter tips having sharp cutting edges or jaws of a number of configurations, and that tips designed especially for shaping, straightening, forming, loop work, stripping, and other desired functions can be conveniently and precisely fixed on the handle portion arms of the present construction in place of the tip configurations herein shown.

What is claimed is:

l. Changeable tip tweezers comprising a handle portion including a pair of elongated resilient arms having corresponding rearward ends joined together forming a heel end, the arms normally extending in forwardly diverging relation and having front ends normally disposed in laterally spaced apart relation, the front end portions of each arm having a channel recess opening through the end surfaces and outer surfaces thereof, the channel recesses having flat base surfaces disposed in selected forwardly convergent planes when the arms occupy their normal forwardly diverging positions and a pair of shoulder surfaces flanking each base surface, a pair of elongated, forwardly converging removable tip members extending from said front end portions and terminating in forward working ends, said tip members having integral mounting formations at their rearward ends to be respectively nested in said channel recesses, the mounting formations having three precision shaped surfaces including an inner face and a pair of opposing shoulders adjoining the face to be abutted and precisely positioned by said base and shoulder surfaces of the channel recess for locating the two tip members in accurate preselected relative alinement, and threaded fasteners carried by said arms and extending through said mounting formations having manually rotatable head members lying outwardly of the arms to be manipulated for mounting and demounting of the tips on said arms, said head members having portions projecting beyond the lower edges of the arms adjacent their front ends to define a pair of transversely spaced rest surfaces coactive with the heel end portion to provide three-point support of the tweezers on a horizontal surface.

2. Changeable tip tweezers as defined in claim 1, wherein said channel recesses are of wedge shaped configuration providing triangular upper and lower surfaces defining said opposing shoulders having their apices pointing toward the heel end.

3. Changeable tip tweezers comprising a handle portion including a pair of elongated resilient arms having corresponding rearward ends joined together forming a heel end, the arms normally extending in forwardly diverging relation and having front ends normally disposed in laterally spaced apart relation, the front end portions of each arm having a channel recess opening through the end surfaces and outer surfaces thereof, the channel recesses having flat base surfaces disposed in selected forwardly convergent planes when the arms occupy their normal forwardly diverging positions and a pair of shoulder surfaces flanking each base surface, a pair of elongated, forwardly converging removable tip members extending from said front end portions and terminating in forward working ends, said tip members having integral mounting formations at their rearward ends to be respectively nested in said channel recesses, the mounting formations having three precision shaped surfaces including an inner face and a pair of opposing shoulders adjoining the face to be abutted and precisely positioned by said base and shoulder surfaces of the channel recess for locating the two tip members in accurate preselected relative alinement, and threaded fasteners carried by said arms and extending through said mounting formations having manually rotatable head members lying outwardly of the arms to be manipulated for mounting and demounting of the tips on said arms, said head members being circular threaded members of greater diameter than the maximum transverse dimension of each tweezer arm providing enlarged finger discs to be engaged by the user's fingers and the circular edges of which define a pair of rest surfaces coactive with the heel end portion to provide three-point support of the tweezers on a horizontal surface.

4. Changeable tip tweezers as defined in claim 3, wherein said channel recesses are of wedge shaped configuration providing triangular upper and lower surfaces defining said opposing shoulders having their apices pointing toward the heel end.

5. Changeable tip tweezers as defined in claim 3, wherein said tip members each have two-stage mounting formations of stepped configuration at their rearward ends, the stages providing a pair of apertured stage formations shaped to precisely nest into the companion channel recesses of the tweezer arms at two lon- 8 gitudinally spaced positions and providing outwardly facing flat landings which lie in parallel planes when the arms occupy their normal positions to be abutted by restraining surface portions of said head members.

6. Changeable tip tweezers as defined in claim 1, wherein said channel recesses are of wedge shaped configuration providing triangular upper and lower surfaces defining said opposing shoulders having their apices pointing toward the heel end and said shoulders being in parallel planes perpendicular to the base surface therebetween and parallel to the longitudinal center axis of the tweezers.

7. Changeable tip tweezers as defined in claim 6, wherein said tip members each have two-stage formations of stepped configuration at their rearward ends, the stages providing a pair of apertured stage formations shaped to precisely nest into the companion channel recesses of the tweezer arms at two longitudinally spaced positions and providing outwardly facing flat landings which lie in parallel planes when the arms occupy their normal positions to be abutted by restraining surface portions of said head members.

8. Tweezers, comprising a pair of elongated elements defining a handle portion fonned of a pair of elongated resilient arm portions having corresponding rearward ends joined together forming a heel end, the arm portions normally extending in forwardly diverging relation and having portions intermediate the length of the tweezers normally disposed in laterally spaced apart relation, said tweezers including a pair of elongated, forwardly converging tip portions extending from said intermediate portions to the working end of the tweezers and terminating in working points, said tip portions being joined to said arm portions and positioned in accurate preselected relative alignment, and a pair of manually rotatable head members lying outwardly of the arm portions threadedly mounted thereto at said intermediate portions, said head members forming threaded members having edge portions projecting beyond the lower edges of said arm portions at said intermediate portions to define a pair of transversely spaced rest surfaces coactive with the heel end portion to provide three-point support of the tweezers on a horizontal surface.

9. Tweezers as defined in claim 8, wherein said threaded members are cylindrical members of greater diameter than the maximum transverse dimension of each tweezer arm portion and have outwardly concave surfaces providing enlarged finger discs to be engaged by the users fingers and the circular edges of which define said pair of rest surfaces.

Claims

1. Changeable tip tweezers comprising a handle Portion including a pair of elongated resilient arms having corresponding rearward ends joined together forming a heel end, the arms normally extending in forwardly diverging relation and having front ends normally disposed in laterally spaced apart relation, the front end portions of each arm having a channel recess opening through the end surfaces and outer surfaces thereof, the channel recesses having flat base surfaces disposed in selected forwardly convergent planes when the arms occupy their normal forwardly diverging positions and a pair of shoulder surfaces flanking each base surface, a pair of elongated, forwardly converging removable tip members extending from said front end portions and terminating in forward working ends, said tip members having integral mounting formations at their rearward ends to be respectively nested in said channel recesses, the mounting formations having three precision shaped surfaces including an inner face and a pair of opposing shoulders adjoining the face to be abutted and precisely positioned by said base and shoulder surfaces of the channel recess for locating the two tip members in accurate preselected relative alinement, and threaded fasteners carried by said arms and extending through said mounting formations having manually rotatable head members lying outwardly of the arms to be manipulated for mounting and demounting of the tips on said arms, said head members having portions projecting beyond the lower edges of the arms adjacent their front ends to define a pair of transversely spaced rest surfaces coactive with the heel end portion to provide threepoint support of the tweezers on a horizontal surface.

3. Changeable tip tweezers comprising a handle portion including a pair of elongated resilient arms having corresponding rearward ends joined together forming a heel end, the arms normally extending in forwardly diverging relation and having front ends normally disposed in laterally spaced apart relation, the front end portions of each arm having a channel recess opening through the end surfaces and outer surfaces thereof, the channel recesses having flat base surfaces disposed in selected forwardly convergent planes when the arms occupy their normal forwardly diverging positions and a pair of shoulder surfaces flanking each base surface, a pair of elongated, forwardly converging removable tip members extending from said front end portions and terminating in forward working ends, said tip members having integral mounting formations at their rearward ends to be respectively nested in said channel recesses, the mounting formations having three precision shaped surfaces including an inner face and a pair of opposing shoulders adjoining the face to be abutted and precisely positioned by said base and shoulder surfaces of the channel recess for locating the two tip members in accurate preselected relative alinement, and threaded fasteners carried by said arms and extending through said mounting formations having manually rotatable head members lying outwardly of the arms to be manipulated for mounting and demounting of the tips on said arms, said head members being circular threaded members of greater diameter than the maximum transverse dimension of each tweezer arm providing enlarged finger discs to be engaged by the user''s fingers and the circular edges of which define a pair of rest surfaces coactive with the heel end portion to provide three-point support of the tweezers on a horizontal surface.

5. Changeable tip tweezers as defined in Claim 3, wherein said tip members each have two-stage mounting formations of stepped configuration at their rearward ends, the stages providing a pair of apertured stage formations shaped to precisely nest into the companion channel recesses of the tweezer arms at two longitudinally spaced positions and providing outwardly facing flat landings which lie in parallel planes when the arms occupy their normal positions to be abutted by restraining surface portions of said head members.

8. Tweezers, comprising a pair of elongated elements defining a handle portion formed of a pair of elongated resilient arm portions having corresponding rearward ends joined together forming a heel end, the arm portions normally extending in forwardly diverging relation and having portions intermediate the length of the tweezers normally disposed in laterally spaced apart relation, said tweezers including a pair of elongated, forwardly converging tip portions extending from said intermediate portions to the working end of the tweezers and terminating in working points, said tip portions being joined to said arm portions and positioned in accurate preselected relative alignment, and a pair of manually rotatable head members lying outwardly of the arm portions threadedly mounted thereto at said intermediate portions, said head members forming threaded members having edge portions projecting beyond the lower edges of said arm portions at said intermediate portions to define a pair of transversely spaced rest surfaces coactive with the heel end portion to provide three-point support of the tweezers on a horizontal surface.

9. Tweezers as defined in claim 8, wherein said threaded members are cylindrical members of greater diameter than the maximum transverse dimension of each tweezer arm portion and have outwardly concave surfaces providing enlarged finger discs to be engaged by the user''s fingers and the circular edges of which define said pair of rest surfaces.