JPH091470A - Combined screwdriver with bit holder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric insulation hand tool having a sufficient torque strength and generating no detachment of magnet from a socket. SOLUTION: An insulation hand tool has a long complex shank 41 and to its work end a bit holder difining a polygonal socket 47 in which a pressure fitted projection is fitted under pressure is fixed. The work end of the shank 41 is hollow and in the hollow part the bit holder 45 is received. A shaft hole 26 of the holder 45 may be a through hole and be terminated before the socket 47. A handle end of the shank 41 may have a small dia. The inner end of the hole 26 of the bit holder 45 receives a permanent magnet and a keeper while the outer end thereof is enlarged to define the socket 47 which receives the bit magnetically retained in a male-female fittable manner. The holder 45 is caulked to the magnet and it retains the magnet at a proper position.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a relatively non-conducting hand tool for safe use in applications that may come into contact with a power source.

[0002]

The present invention is an improved version of the electrically insulating composite hand tool disclosed in US Pat. No. 5,259,277, the disclosure of which is incorporated herein by reference.

Prior art tools use a composite shank and a composite sleeve, which at its rear end receives the front end of the shank and at its front end a metal bit holder carrying a permanent magnet, which permanent magnet. Magnetically retain the associated bit in the holder.
The sleeve is glued to the shank and bit holder. This device is useful for holding the bit removably. In fact, the handle of this prior art tool is hollow to hold the replacement bit.

[0004]

This prior art arrangement effectively acts as an electrical insulator and also removably retains the bit in the bit holder. However, its magnetic nature limits its use to bits made of magnetized material.

Another disadvantage of this prior art arrangement is that it has been found that some applications provide insufficient torque strength. More specifically, the bit holder is fixed to the shank only by the sleeve,
The sleeve is a hollow tubular member that is fairly thin. It has been found that in high torque applications, the sleeve itself does not work, or the adhesive bond between the sleeve and the bit holder or shank does not work.

Moreover, in this prior art construction, the magnet is adhesively bonded to the hole which is axially located at the end of the bit holder which is in communication with the socket opposite the bit receiving socket. It is formed. Therefore, the bit may come into contact with the magnet and the magnet may be impacted and become loose and disengage from the inner end of the socket.

It is also known to provide a recessed bit frictionally retained in a socket or bit holder, such as the arrangement disclosed in US Pat. No. 5,295,423.

[0008]

SUMMARY OF THE INVENTION A general object of the present invention is to provide an improved version of the type which retains the bit on the shank, avoiding the drawbacks of conventional tools while at the same time providing structural and operational advantages. It is to provide an electrically insulated handle tool.

An important feature of the present invention is to provide an electrically insulating hand tool of the type described which joins the bit holder to the shank with a joint of improved torsional strength.

Another feature of the invention is to provide a hand tool of the above type adapted for use with non-magnetic bits.

Yet another feature of the present invention is to provide a hand tool of the above type adapted to permanently or semi-permanently mount a bit on the hand tool.

Yet another feature of the present invention is to provide a hand tool of the type described which utilizes the magnetic retention of the bit to effectively prevent the magnet from disengaging from the bit receiving socket.

In connection with the above features, another feature of the present invention is to provide a hand tool of the above type which is of simple and economical construction.

These and some other features of the invention include an elongated member formed of an electrically insulating material having a longitudinal axis with a handle at one end and a working end at the other end. A shank, an elongated bit holder coaxially fixed to the shank at the working end, the bit holder having a polygonal cross-section axial socket formed at the outer end, and a male / female-receptive socket for receiving the socket. Achieved by providing an insulated hand tool including a bit having a lateral protrusion that press fits into the socket.

Yet another feature of the present invention is an elongated shank formed of an electrically insulating material having a longitudinal axis with a handle at one end and a working end at the other end.
An elongated bit holder fixed to the working end of the shank and extending coaxially from the shank, wherein an axial hole is formed at an outer end thereof, the axial hole having a cylindrical inner portion and a polygonal cross section. An enlarged outer portion of the permanent magnet and a permanent magnet received in the inner portion of the shaft hole, the permanent magnet being crimped to the permanent magnet. It is achieved by providing an insulating hand tool, characterized in that is fixed to the shaft hole.

The present invention consists of novel features and combinations of parts which will be fully described below, shown in the accompanying drawings and particularly pointed out in the claims, without departing from the spirit of the invention. It will be appreciated that various changes in detail may be made without sacrificing any of the advantages of the invention.

[0017]

DETAILED DESCRIPTION OF THE INVENTION Referring to FIGS. 1, 3 and 5-7, an electrically insulated hand tool 20 in the form of a screwdriver is shown. Tool 20 has a composite structure elongated shank 21 which may be of the type disclosed in the aforementioned US Pat. No. 5,259,277. Shank 21
Has a handle end 22 and a working end 23. Handle 25, which is formed of an electrically insulating material such as a suitable plastic, may be shank 22 by suitable means such as those disclosed in the aforementioned US Pat. No. 5,259,277.
It is firmly fixed to the handle end 22 of the. The working end 23 of the shank 21 has a cylindrical axial bore 26 formed therein, the outer surface of which is tapered or chamfered at its distal end 27.

The hand tool 20 is formed of a suitable material such as steel and includes an elongated cylindrical bit holder 30 telescopically received within an axial bore 26 of the shank 21,
The length of the bit holder 30 is approximately the same as the depth of the shaft hole 26 so that the bit holder 30 does not project axially outwardly beyond the working end 23 of the shank 21. The bit holder 30 has an axial through hole 31 that expands near the outer edge to define a hexagonal bit socket 32. The bit holder 30 is securely fixed in the shaft hole 26 with a suitable adhesive 34.

The bit socket 32 is adapted to receive the related bit 35 therein so as to be connectable to male and female. More particularly, the bit 35 has a hexagonal shank 36 dimensioned for mating with the bit socket 32, the shank 36 having lateral outwardly projecting projections 37 having the characteristics of a forging depression or bead. . The shank 36 is dimensioned such that the protrusion 37 is press fit within the bit socket 32, thereby permanently or semi-permanently attaching the bit 35 to the hand tool 20. In this regard, the inner end of the bit socket 32 defines a peripheral shoulder 38 which serves to limit the depth of insertion of the bit 35 in the socket 32.

Since the bit holder 30 is adhesively secured directly to the shank 21 along its entire length, it produces greater torsional strength than the hand tool disclosed in the aforementioned US Pat. No. 5,259,277.

With reference to FIGS. 2, 4 and 8-10, there is shown another hand tool 40 also having the characteristics of a screwdriver and in accordance with another embodiment of the present invention. The hand tool 40 has an elongated shank 41 which is formed of the same material as the shank 21 of the tool 20, except that it has a small diameter handle end 42 joined to the working end 23 by a tapered portion 44. Good. Tool 40
Is a bit holder 30 except that it does not have a through hole.
And an elongated cylindrical bit holder 45 similar to.
Rather, the bit holder 45 has a cylindrical shaft hole 46 formed at its rear end and a hexagonal bit socket 47 formed at its front end in the axial direction.
No. 7 ends before the shaft hole 46, and the intermediate inner wall 48
Leave. The outer surface of the bit holder 45 is 49
It is chamfered as shown by.

The bit holder 45 is adhesively secured within the shank 41 axial bore 26 in a manner similar to that described for the tool 20. Outer end 4 of bit holder 45
The chamfer at 9 defines an annular recess for wiping off excess adhesive. The hand tool 40 uses the associated bit 3 in a manner similar to that described for the hand tool 20.
Operate 5 and accept. If desired, the bit holder 45 may be provided with countersinks at the outer end of the bit socket 47 as described with respect to the bit holder 30 and the front end of the bit holder 30 may also have a chamfered outer surface similar to the bit holder 45. It will be understood that it is good.

Referring to FIGS. 11 and 12, there is shown a tool shank 50 having an outer cylindrical surface 51 which, instead of being pierced at the working end, of a small diameter working shoulder defining an annular shoulder 53. It is generally the same as the shank 21 described above in connection with the tool 20 except that it has an end 52.

The shank 50 is the same as the above-mentioned US Pat.
Similar to the corresponding sleeve disclosed in 59,277,
And is adapted for use with an associated elongated tubular sleeve 55 which may be formed of the same material. However, the sleeve 55 has an outer surface that may be tapered or chamfered at its ends as at 56 and 57. The shank 50 is the bit holder 45 described above.
To be used for. More specifically, shank 5
The small diameter working end 52 of 0 is telescopically received within the cylindrical bore 46 of the bit holder 45, where the adhesive 54
Glued. Preferably, each component is sized so that the outer diameter of the bit holder 45 is approximately the same as the diameter of the outer surface 51 of the shank 50.

The sleeve 55 has a tapered front end 57 which is substantially flush with the front end of the bit holder 45.
It is received on the bit holder 45 in a telescopic manner. The sleeve 55 has a length such that when assembled, it overlaps the outer surface 51 of the shank 50 by a distance that is substantially the same as the length of the bit holder 45. The sleeve 55 is preferably adhesively secured to the shank surface 51 and the bit holder 45.

Tools incorporating shank 50 operate in much the same manner as tool 40 described above. This structure
It provides significantly greater torsional strength than the prior art tools disclosed in the aforementioned US Pat. No. 5,259,277 because the bit holder 45 is glued along its inner and outer diameters. And is bonded directly to the shank 50 along the entire length of the working end 52.

Referring to FIGS. 13-15, there is shown a shank 60 which can be substituted for any of the shanks 21, 42 and 50 described above.
0 is substantially the same as the shank 50 described in connection with FIG. 11 except that it does not have a small diameter working end. Rather, the shank 60 terminates in a flat circular working end surface 61, which has the same diameter as the rest of the shank 60. The shank 60 is adapted for use with the same sleeve 55 described above in connection with FIG. The shank 60 is also adapted for use with a bit holder 62 formed of a suitable metal such as non-magnetic stainless steel. The front end of the bit holder 62 is
A cylindrical hole 63 is formed in the axial direction that is shallower than the length. A hexagonal bit socket 64 is formed at the front end of the cylindrical hole 63.

A cylindrical magnetic keeper 65, made of a suitable magnetizable material, is received in the cylindrical bore 63 and seated at its inner end. Further, the elongated cylindrical permanent magnet 66 is received in the cylindrical hole 63 and seated in the keeper 65, and when the permanent magnet is fully seated in the cylindrical hole 63, the outer end of the hexagonal bit socket 64 is located. It has a length such that it is disposed substantially at the inner end. When the parts are assembled in this manner, the walls of the bit holder 62 are crimped at diametrically opposed positions, such as at 67, creating a radially inwardly extending projection 68 that securely clamps the magnet 66 in place. . If desired, the outer surface of the bit holder 62 may be machined and rounded back. In this regard, the bit holder 62
Is preferably dimensioned so that the outer diameter is almost the same as the outer diameter of the shank 60.

The closed end of the assembled bit holder 62 is fixed to the working end surface 61 of the shank 60 with an adhesive. The sleeve 55 is then moved until the tapered front end 57 is substantially flush with the outer end of the bit holder 62.
It is received on the bit holder 62 in a nested manner. Preferably, the sleeve 55 has a length such that it overlaps the end of the shank 60 by approximately the same distance as the length of the bit holder 62. The sleeve 55 is fixed to the shank 60 and the bit holder 62 along its entire length with an adhesive.

In use, a bit (not shown) formed of magnetizable metal is removably and matingly received within the bit socket 64 and held therein by the magnetic force of magnet 66. The magnetic keeper 65 plays a role of controlling the direction of the magnetic force lines to achieve an optimum magnetic holding force.
It will be appreciated that, in this embodiment of the invention, the magnet 66 bottoms the bit holder 62 so that it cannot be moved inward from the bit socket 64 by engagement with the associated bit.

From the above, the present invention is based on the aforementioned US Pat.
It provides all of the electrical isolation advantages of the hand tools disclosed in US Pat. No. 259,277, while also providing increased torsional strength, adaptation to permanent or semi-permanent bit attachment, and / or improved magnetic retention. Is recognized. Another important aspect of the invention is that bit holders 30 and 45, which can be used interchangeably with different embodiments of the invention.
And the use of components such as sleeve 55. Although the preferred embodiment of the present invention is described as being implemented in a screwdriver, it will be appreciated that the principles of the present invention may be used with nut drivers or other types of hand tools.

While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that changes and modifications can be made in a broader aspect without departing from the invention. is there. Therefore, the object of the appended claims covers all changes and modifications that fall within the true spirit and scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. The actual scope of the invention is intended to be defined in the following claims when viewed in proper context according to the prior art.

[Brief description of the drawings]

FIG. 1 is a side elevational view of a hand tool constructed in accordance with a first embodiment of the present invention and embodying features thereof.

FIG. 2 is a side elevational view of a hand tool according to a second embodiment of the present invention.

3 is an enlarged cutaway sectional view taken along line 3-3 of FIG.

FIG. 4 is an enlarged cutaway sectional view taken along line 2-2 of FIG.

5 is a reduced-scale cross-sectional view of the bit holder of the tool of FIG.

6 is an enlarged end elevation view of the left end of the bit holder of FIG.

7 is an enlarged end elevation view of the right end of the bit holder of FIG.

FIG. 8 is a reduced cross-sectional view of the bit holder of the tool of FIG.

9 is an enlarged end elevation view of the left end of the bit holder of FIG.

10 is an enlarged end elevational view of the right end of the bit holder of FIG.

FIG. 11 is an enlarged cutaway exploded perspective view of a tool according to another embodiment of the present invention.

12 is a side elevational view in partial section of the tool of FIG.

FIG. 13 of a tool according to yet another embodiment of the present invention,
The figure similar to FIG.

14 is a cross-sectional view of the bit holder subassembly of the tool of FIG.

FIG. 15 is a cutaway side elevational view of a partial cross section of the tool of FIG.

[Explanation of symbols]

 20, 40 Hand tool 21, 41, 60 Shank 22 Handle 23, 52 Working end 26, 46 Shaft hole 30, 45, 62 Bit holder 31 Through hole 32, 47, 64 Hexagon bit socket 35 Bit 36 Hexagonal shank 37 Protrusion 44 Taper Attached portion 49 Outer end 50 Tool shank 51 Outer cylindrical surface 54 Adhesive 55 Sleeve 57 Front end 61 Working end surface 63 Cylindrical hole 65 Magnetic keeper 66 Permanent magnet

Claims (8)

[Claims] 1. An elongated shank formed of an electrically insulating material having a longitudinal axis, a handle at one end, and a working end defined at the other end, the working end being coaxial with the shank. An elongated bit holder fixed to the outer peripheral end of the socket, the bit holder having a polygonal axial section formed at an outer end thereof, and a bit received in the socket so as to be connectable with a male and female, and press-fit into the socket. An insulated hand tool including the bit with lateral protrusions. 2. The hand tool of claim 1, wherein the working end of the shank has an axial bore formed therein and the bit holder is telescopically received in the axial bore. 3. The hand tool of claim 2, wherein the bit holder is adhesively secured in the shank hole. 4. The hand tool of claim 1, wherein the working end of the shank has a smaller diameter with respect to the rest of the shank. 5. The hand tool of claim 4, wherein the bit holder has an axial bore formed in its inner end, the axial bore receiving the small diameter working end of the shank. 6. The hand tool of claim 5, further including a tubular sleeve surrounding an adjacent portion of the bit holder and the shank. 7. The hand tool of claim 1, wherein the shank is formed of a composite epoxy / glass material. 8. An elongated shank formed of electrically insulating material having a longitudinal axis with a handle at one end and a working end at the other end, secured to the working end of the shank. An elongated bit holder extending coaxially from the shank, wherein an axial hole is formed at an outer end thereof, the axial hole having a cylindrical inner portion and an enlarged outer portion having a polygonal cross section. Such a bit holder and a permanent magnet received in the inner portion of the shaft hole, the bit holder being caulked against the permanent magnet to secure the permanent magnet in the shaft hole. A characteristic insulated hand tool.