Stonesetter's Hand Tool

Abstract

An impact generating hand tool for setting gem stones in a ring mounting or the like and which is configured to facilitate accurate guidance of the workpiece engaging portion of the tool to guard against striking and possibly fracturing the gem stone. The tool includes a downwardly directed handle, and a hammer having a workpiece engaging portion at the lower end thereof which is spaced from the handle a distance sufficient to permit the operator to contact and guide the workpiece engaging portion with his little finger. The hammer is reciprocated to provide the desired impacts on the workpiece by a mechanism which includes a reciprocating shaft positioned to strike or impact the hammer at the lowermost portion of its movement, a variable speed electric motor for reciprocating the shaft, and a motor speed control switch carried on the handle whereby the frequency and intensity of the impacts on the hammer and thus the workpiece may be controlled.

Description

The present invention relates to an impact generating hand tool useful in mounting gem stones in the setting of rings or other jewelry pieces made of the precious metals.

In mounting a gem stone in a ring or the like, a seat is initially cut or otherwise formed in the metal to provide the setting into which the stone is inserted. A portion of the metal surrounding the stone is then bent or swaged over the edges of the stone to permanently hold it in the setting. Depending upon the type of setting involved, the bent or swaged portions of the setting may take various forms, such as upright prongs which are bent over the edges of the stone, or a rim of metal which the stonesetter turns over the edges all the way around the stone.

Stonesetters presently utilize a hand tool in the form of a punch or swage, and a mallet, to shape the metal about the edges of the stone. As can be readily appreciated, a great deal of skill and experience is required in order to properly shape the metal about the edges of the stone by means of such tools. Also, great care must be exercised since a misdirected blow can easily cleave or fracture the stone. Thus, the operation is time consuming and expensive. While powered hand tools which employ compressed air or an electric motor to oscillate a workpiece engaging hammer have been employed to set gem stones, such tools are generally unsatisfactoy since the intensity of the impacts from the hammer cannot be readily controlled and they are difficult to accurately guide in relation to the workpiece.

It is accordingly an object of the present invention to provide a powered stonesetter's hand tool which is adapted to efficiently shape the metal of a setting about a gem stone, and which is designed to alleviate the danger of fracturing the stone.

Another object of the present invention is to provide a stonesetter's hand tool having provision for delivering a series of impacts to the setting which may be accurately controlled as to frequency and intensity to thereby permit careful control of the displacement of the metal.

It is a further object of the present invention to provide a stonesetter's hand tool which is configured to permit the operator to contact and engage the workpiece engaging portion of the tool with one of his fingers to thereby permit him to guide the tool and accurately position the impacts on the setting and thus reduce the danger of striking and fracturing the stone.

These and other objects and advantages of the present invention are achieved in the embodiment of the invention illustrated herein by the provision of a hand tool which comprises a housing having a downwardly extending handle adapted to be gripped by one hand of the operator, a reciprocable hammer carried by the housing and having a workpiece engaging portion at the lower end thereof which is spaced from the handle a distance sufficient to permit the operator to contact and guide the workpiece engaging portion with one of his fingers, and impact means including a variable speed electric motor and controlling switch positioned on the handle for delivering a series of controlled impacts upon the hammer. A spring is positioned beneath the hammer such that the hammer is reciprocated by the combined section of the impact means and spring. Thus the operator is able to control the speed of the electric motor by adjustment of the switch to permit accurate control of the frequency and intensity of the impacts delivered to the hammer and thus the workpiece. Also, the workpiece engaging portion of the tool may be accurately guided by the finger of the operator such that the point of application of the impacts to the workpiece can be controlled.

Some of the objects and advantages of the invention having been stated, others will appear as the description proceeds, when taken in connection with the accompanying drawings, in which

FIG. 1 is a perspective view of a stonesetter's hand tool embodying the features of the present invention and further illustrating the manner in which it is employed to mount a gem stone in a ring setting;

FIG. 2 is a side elevational view, partly sectioned, of the tool shown in FIG. 1;

FIG. 3 is a sectional end view taken substantially along the line 3--3 of FIG. 2;

FIG. 4 is a fragmentary sectional view schematically illustrating the electrical switch employed with the present invention.

Referring more sepcifically to the drawings, a stonesetter's hand tool embodying the features of the present invention is indicated generally at 10. The tool includes a supporting housing which comprises a handle 12, a central body section 14, and upper and lower forward body sections 16 and 18, respectively. The handle 12 extends generally downwardly, and is somewhat arcuately shaped to be conveniently gripped by one hand of the operator in the manner shown in FIG. 1. As will become apparent, the tool may be gripped and operated by either the right or the left hand.

A variable speed control switch 20 is mounted within the upper portion of the handle and is positioned along the inside edge to be engaged by the index finger of the operator. The switch is of conventional construction and of a type commonly employed in small electrical hand tools such as drills. Generally, the switch comprises a laterally translatable slide 22 which is biased outwardly by the spring 24. A stop member 26 is carried by a threaded member 28 such that the extent of the inward movement of the slide may be adjustably limited by rotating the threaded member 28 and thereby translating the stop member 26 toward or away from the abutment wall 29. The slide 22 is operatively connected to the electrical circuit 30 such that the output from the switch is controlled by the extent of the inward displacement of the slide 22. A switch of this type is manufactured by the Skil Corporation of Chicago, Ill., as part number 45265.

The central body section 14 of the housing mounts a conventional variable speed electric motor 32 which is operatively connected to the switch 20. Thus, the speed of the motor 32 is controlled by the extent of the lateral displacement of the slide 22 of switch 20, with the maximum speed of the motor being controlled by the position of the stop member 26. The output shaft of the motor 32 mounts a gear wheel 34, and a following gear wheel 36 is journaled to the central body section 14 and operatively engages the gear 34. A pin 38 is carried by the gear wheel 36 adjacent the outer periphery thereof and thus lies eccentric to the axis of rotation of the gear 36. The pin 38 will be seen to extend in a direction generally parallel to the axes of rotation of the gears 34 and 36, and as the gears rotate, the pin 38 circumscribes the circle illustrated schematically at 40 in FIG. 3.

The upper forward body section 16 includes a central cavity 42 and a transverse cylindrical bore 44 extending vertically completely through the section 16 (and cavity 42) to define a central axis. The cavity 42 encloses the gears 34 and 36, as well as the central portion of a cylindrical shaft 46 which is slidably mounted in the bore 44. The central portion of the shaft 46 fixedly carries a transversely extending guide member 48, one face of which defines a lateral slot 49 which is positioned to receive the pin 38 as best seen in FIG. 3. As will be apparent from the drawings, the axes of rotation of the gear wheels 34 and 36 perpendicularly intersect the central axis as defined by the bore 44 and shaft 46. Thus rotation of the gear wheels 34, 36 by the motor 32 causes the pin 38 to reciprocate the shaft 46 along the central axis between a raised position shown in solid lines in FIG. 2, and a lowered position shown in dashed lines.

The lower forward body section 18 includes a vertically extending bore which is coaxially aligned with the central axis defined by the bore 44, and which comprises an upper enlarged diameter portion 50 and a lower portion 52 of reduced diameter, to define a transverse shoulder 53 therebetween. A hammer 54 is mounted within the bore of the body section 18 and thus along the central axis and in generally parallel relation with the handle 12. The hammer 54 includes an upper cylindrical shaft segment 56 which is dimensioned to closely conform to the bore portion 50, a lower cylindrical shaft segment 58 extending through and below the bore portion 52, a releasable chuck 60 secured to the shaft segment 58 and positioned below the body section 18, and a workpiece engaging member 62 releasably mounted in the chuck 60. A helical spring 64 encircles the shaft segment 58 and is interposed between the upper shaft segment 56 and the shoulder 53 to bias the hammer upwardly as shown in FIG. 2.

The chuck 60 is of conventional design and includes a plurality of lower jaw segments 65 which are adapted to be manually expanded to release and permit separation and replacement of the workpiece engaging member 62. As will be appreciated by those skilled in the art, the lower end of the workpiece engaging member 62 is generally sharp or pointed and may take various configurations depending upon the type of setting being prepared. Also, it will be apparent from FIGS. 1 and 2 that the workpiece engaging member 62 is laterally spaced from the lower portion of the handle 12 a distance sufficient to permit the operator to contact and guide the same with his little finger while gripping the handle.

In operation, the handle 12 is gripped by the operator in the manner shown in FIG. 1, with the index finger overlying and controlling the switch 20 and the little finger extended to engage the workpiece engaging member 62. Upon depressing the switch 20, the electric motor 32 is energized to rotate the gears 34 and 36 and thereby reciprocate the shaft 46 between its raised and lowered positions. As the shaft reaches its lowered position during each reciprocation, the lower end 66 strikes the upper end 68 of the hammer segment 56 causing the hammer to be translated downwardly against the biasing force of the spring 64. Typically, the elevation of the upper end 68 of the hammer 54 in its normal raised position (as shown in solid lines in FIG. 2) is about 1/8 inch or less above the elevation of the lower end 66 of the shaft 46 when the shaft reaches its lowered position (shown in dashed lines in FIG. 2). Thus the hammer 54 is reciprocated along the central axis between its raised position (shown in solid lines in FIG. 2) and a lowered position (shown in dashed lines), which represents a distance of about 1/8 inch or less, by the combined action of the impacts from the shaft 46 and the spring 64. By controlling the extent to which the slide 22 of switch 20 is depressed, the speed of the motor 32 and thus the frequency and intensity or sharpness of the impacts upon the hammer 54 (and thus the workpiece) may be accurately controlled. This feature can be used to advantage for example by moving a relatively large amount of metal during the initial portion of the setting operation by a series of rapid and sharp impacts, and then applying a less rapid and sharp series during the finishing operation. Also, since the little finger of the operator is in contact with the workpiece engaging member 62, the point of application of these impacts may be carefully guided to prevent contact with the stone thereby reducing the danger of breaking the same.

It should also be noted that the lower segment of the bore 44 of the upper forward body section 16, and the bore 50 of the lower forward body section 18 cooperate to define a substantially air tight enclosure which surrounds the lower end of the shaft 46 and the upper end of the hammer segment 56. The volume of this enclosure is substantially reduced during downward translation of the shaft 46 such that the air entrapped in the enclosure is rapidly compressed and thus serves to somewhat soften or dampen the sharpness of the impact between the shaft and hammer. It is believed that this dampening effect further serves to reduce the danger of breakage of the stone should the stone be accidentally contacted by the workpiece engaging member 62.

In the drawings and specification, there has been set forth a preferred embodiment of the invention, and although sepcific terms are employed, they are used in a descriptive and generic sense only and not for purposes of limitation.

Claims

That which is claimed is:

1. An impact generating hand tool useful in setting gem stones or the like and comprising

a housing including a downwardly extending handle adapted to be gripped by one hand of the operator,

a shaft carried by said housing and defining a central axis which extends generally parallel to said handle, said shaft including a lower end and being translatable along said central axis between a raised position and a lowered position,

power means carried by said housing for reciprocating said shaft along said central axis between said raised and lowered positions, said power means including a control switch mounted on said handle to permit the operator to actuate the switch with one of his fingers from the hand gripping the handle,

a hammer carried by said housing coaxially below said shaft, said hammer including an upper end and being translatable along said central axis between a raised position and a lowered position, the elevation of said upper end of said hammer when in its raised position being somewhat above the elevation of said lower end of said shaft when in its lowered position, said hammer further including an exposed workpiece engaging portion at the lower end thereof which is laterally spaced from said handle a distance sufficient to permit the operator to contact and guide the same with another of his fingers from the hand gripping the handle, and

resilient means operatively positioned between said housing and hammer for raising said hammer from its lowered position to its raised position whereby reciprocation of said shaft by said power means causes said shaft lower end to intermittently impact said hammer upper end and to thereby depress said hammer to its lowered position such that the same is reciprocated between its upper and lowered positions.

2. The hand tool as defined in claim 1 wherein said power means for reciprocating said shaft includes a variable speed electric motor and said switch includes means for varying the speed of said motor and thus the frequency of the reciprocation of said shaft and hammer.

3. The hand tool as defined in claim 2 wherein said means for varying the speed of said motor comprises a laterally translatable slide, circuit means operatively controlled by the positioning of said slide for varying the speed of said electric motor, and adjustment means for limiting the translation of said slide and thus the maximum speed of said electric motor.

4. The hand tool as defined in claim 1 wherein the elevation of said upper end of said hammer when in its raised position is about 1/8 inch or less above the elevation of said lower end of said shaft when in its lowered position.

5. The hand tool as defined in claim 1 wherein said housing defines a substantially air tight enclosure surrounding the lower end of said shaft and the upper end of said hammer, the volume of said enclosure being substantially reduced during downward translation of said shaft such that the air entrapped in said enclosure serves to somewhat dampen the impacts between said shaft and hammer.

6. The hand tool as defined in claim 1 wherein said resilient means comprises a helical spring encircling a portion of said hammer.

7. A stonesetter's hand tool useful in delivering a series of impacts to a setting in an ornamental ring or the like to displace the material of the setting over the edges of a gem stone and thereby hold the same securely in the setting, said hand tool having provision for accurately controlling the frequency, intensity and point of application of the impacts whereby the gem stone may be efficiently and securely set while minimizing the danger of breaking the stone and comprising

a housing including a downwardly extending handle adapted to be gripped by one hand of the operator,

a hammer carried by said housing and mounted for limited reciprocation along a central axis which extends generally parallel to said handle, said hammer including an exposed workpiece engaging portion at the lower end thereof which is laterally spaced from said handle a distance sufficient to permit the operator to contact and guide the same with one of his fingers from the hand gripping the handle,

impact means carried by said housing for delivering a series of controlled impacts upon said hammer to translate said hammer downwardly along said central axis upon each impact, said impact means including a control switch mounted on said handle to permit the operator to actuate the switch with another of his fingers from the hand gripping the handle, and

resilient means for translating said hammer upwardly after each impact, whereby said hammer is reciprocated along said central axis by the combined action of said impact means and resilient means.

8. The hand tool as defined in claim 7 wherein said impact means further includes a variable speed electric motor, a reciprocable shaft carried by said housing coaxially with and immediately above said hammer, and means for operatively interconnecting said shaft and said electric motor such that operation of said motor acts to reciprocate said shaft, and said switch includes means for controlling the speed of said motor.

9. The hand tool as defined in claim 8 wherein said means for interconnecting said shaft and electric motor comprises means defining a transverse slot carried by said shaft, a gear wheel operatively connected to said electric motor and mounted for rotation about a second axis extending perpendicular to said central axis, and a pin carried by said gear wheel adjacent the outer circumference thereof and extending in a direction parallel to said second axis and into said slot whereby operation of said electric motor causes said gear wheel to rotate and said pin to circumscribe a circle and translate within said slot to thereby reciprocate said shaft along said central axis.

10. The hand tool as defined in claim 9 wherein said hammer further includes chuck means for releasably interconnecting said workpiece engaging portion.