Telescopic shaft magnetic retriever

A telescopic shaft magnetic retriever includes a telescopic shaft having a conductive battery holder at a tip thereof, and an insulative and transparent lamp holder adapted to hold a lamp and a magnet for retrieving screws, nuts, tools and other steel parts from inaccessible places. The lamp has a first contact connected electrically to a pole of the battery set and a second contact. The lamp holder allows passage of light emitted from the lamp. The retriever further includes a conductive tubular sleeve which is connected threadedly to the conductive battery holder and the lamp holder and which has an end surface in electrical contact with the second contact of the lamp. The battery set, the conductive battery holder, the conductive tubular sleeve, and the lamp constitute an electric circuit. The lamp is switchable by rotating the tubular sleeve relative to the lamp holder.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a magnetic retriever, more particularly to 
a telescopic shaft magnetic retriever which is convenient to operate. 
2. Description of the Related Art 
When screws, nuts, tools or other parts are dropped into inaccessible 
places, a retriever that is provided with a magnet is used to pick them 
up. Moreover, a magnetic retriever having a built-in lighting device is 
particularly useful to retrieve things in the dark. 
U.S. Pat. No. 5,384,319 discloses a telescopic shaft magnetic retriever (R) 
(see FIG. 1), which includes a telescopic shaft 1 having a battery holder 
3 at a tip thereof to hold an insulative socket 3a and a set of dry 
battery cells 4 within the insulative socket 3a. A conductive lamp holder 
5 is fastened to the battery holder 3 to hold a lamp 6. A spring 7 is 
mounted inside the lamp holder 5 and presses against the negative pole of 
the dry battery cells 4. The lamp 6 has a first contact 6a which is 
connected to the spring 7, and a second contact 6b which is isolated from 
the spring 7 while in contact with the conductive lamp holder 5. A 
transparent tube 8 is fastened to the lamp holder 5 to allow passage of 
light emitted from the lamp 6 and to hold a magnet 9 for retrieving 
screws, nuts, tools and other steel parts from inaccessible places. The 
retriever (R) further includes a control rod 2 which is received in a 
longitudinal passage inside the telescopic shaft 1 and the conductive 
battery holder 3. When the telescopic shaft 1 is collapsed, the dry 
battery cells 4 are pushed away from the bottom of the battery holder 3 by 
the control rod 2 to compress the spring 7. Therefore, the battery holder 
3 is insulated from the positive pole of the battery cells 4 and the 
circuit is opened. At this time, the lamp 6 is deactivated. When the 
telescopic shaft 1 is extended out for retrieving things, the control rod 
2 is released from the battery cells 4, so that the spring 7 pushes the 
battery cells 4 backwards to contact the bottom of the battery holder 3, 
thereby turning on the lamp 6. Through the extension of the telescopic 
shaft, the lamp 6 is activated to generate light by means of the action of 
the control rod 2 and the spring 7. 
The conventional retriever with telescopic shaft is convenient to bring 
along. However, the operations of the retriever for turning the lamp on 
and off involve extending and collapsing the telescopic shaft. It is 
desirable if the lamp is switchable without extending or collapsing the 
telescopic shaft. 
SUMMARY OF THE INVENTION 
Therefore, the main object of this invention is to provide a telescopic 
shaft magnetic retriever which has a built-in lighting device with a lamp 
that can be easily switched on and off, and which is more convenient to 
operate. 
Accordingly, the telescopic shaft magnetic retriever of the present 
invention mainly includes a telescopic shaft, an insulative and 
transparent lamp holder and a conductive tubular sleeve. The telescopic 
shaft has a conductive battery holder at a tip thereof to hold an 
insulative socket and a battery set including a predetermined number of 
battery cells within the insulative socket. The insulative and transparent 
lamp holder is adapted to hold a lamp and a magnet for retrieving screws, 
nuts, tools and other steel parts from inaccessible places. The lamp has a 
first contact which is connected electrically to a pole of the battery set 
and a second contact. The lamp holder allows passage of light emitted from 
the lamp. The conductive tubular sleeve is connected threadedly to the 
conductive battery holder and the lamp holder and has an end surface in 
electrical contact with the second contact of the lamp. The battery set, 
the conductive battery holder, the conductive tubular sleeve and the lamp 
constitute an electric circuit, thereby permitting activation of the lamp. 
The conductive tubular sleeve is rotatable relative to the lamp holder to 
move away from the lamp holder, so that the second contact of the lamp is 
electrically disconnected from the conductive sleeve member to deactivate 
the lamp.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIGS. 2 and 3, the telescopic shaft magnetic retriever 10 of 
the preferred embodiment of the present invention is shown to include a 
telescopic shaft 20, a set of battery cells 30, a tubular sleeve 22, a 
spring 60, a lamp holder 40, a lamp 50, and a magnet 70. 
The telescopic shaft 20 is composed of a predetermined number of tubes 11 
which are sleeved on and coupled to one another. The telescopic shaft 20 
is provided with a battery holder 21 at a thinner tip thereof. The battery 
holder 21, which is made of a conductive metal, has an open end portion 
211 which is formed with external screw threads 213 and which is provided 
with an insulative socket 212 at an inner surface thereof. The battery 
cells 30 are loaded within the insulative socket 212 in the open end 
portion 211 of the battery holder 21. The tubular sleeve 22, which is also 
made of a conductive metal, has internally threaded end portions 221 and 
222, and an inner surface formed with an annular groove 224 that has a 
predetermined axial width. 
In this embodiment, the lamp holder 40 is integrally formed from an 
insulative and transparent material. The lamp holder 40 includes a 
narrower tubular section 40b having an inner surface which defines a 
central hole 41, a wider holding body 40a which has an outer diameter 
larger than that of the tubular section 40b and which has an axial 
accommodation chamber 42 for accommodating the lamp 50, and a distal end 
formed with an enlarged hole section 421 which is communicated with the 
axial accommodation chamber 42, for holding a magnet 70 for retrieving 
screws, nuts, tools and other steel parts from inaccessible places. Two 
through holes 43, 43a are formed between and are communicated with the 
central hole 41 and the axial accommodation chamber 42. The narrower 
tubular section 40b is formed with external screw threads 441 for engaging 
the internally threaded end portion 222 of the tubular sleeve 22, and two 
axial slots 45 and 48 through a wall thereof so as to define an elongated 
barb member 49 between the two slots 45 and 48. A shoulder 46 is formed 
between the outer surface of the narrower tubular section 40b and the 
outer surface of the wider holding body 40a. The shoulder 46 is formed 
with a radially extending slot 47 which has a generally semi-circular 
cross-section and which is communicated with the axial slot 45 and the 
through hole 43a. The barb member 49 is capable of being bent radially and 
inwardly and has an enlarged and tapered free end portion 493 that engages 
the annular groove 224 of the tubular sleeve 22. The enlarged and tapered 
free end portion 493 of the barb member 49 has an inclined outer side 
surface 493a and a radially extending inner side surface 493b which is 
transverse to the barb member 49. The inclined outer side surface 493a 
assists the lamp holder 40 when the latter is being inserted into the 
tubular sleeve 22 during assembly of the lamp holder 40 and the tubular 
sleeve 22. The radially extending inner side surface 493b is adapted to be 
confined within the annular groove 224 in the tubular sleeve 22 and thus 
prevents removal of the lamp holder 40 from the tubular sleeve 22. The 
enlarged and tapered free end portion 493 slides axially within the 
annular groove 224 of the tubular sleeve 22 when the tubular sleeve 22 
rotates relative to the lamp holder 40. 
In this embodiment, a light emitting diode is used for the lamp 50 which 
includes a first contact 51 passing through the through hole 43 and 
extending into the central hole 41 of the lamp holder 40, and a second 
contact 52 that is bent to form an L-shape and that includes an axial 
portion 521 and a radial portion 522. The axial portion 521 passes through 
the through hole 43a and is disposed within the lamp holder 40. The radial 
portion 522 extends into the radially extending slot 47 in the shoulder 46 
and extends partially out of the lamp holder 40 to contact an end surface 
of the conductive tubular sleeve 22. The depth of the radially extending 
slot 47 is about one half of the diameter of the second contact 52 of the 
lamp 50. 
The telescopic shaft magnetic retriever 10 of this embodiment further 
includes a coiled compression spring 60 having an end formed with an axial 
extension 61 which is inserted into the through hole 43 so as to couple 
closely with the first contact 51 of the lamp 50 and to help fix the lamp 
50 in the accommodation chamber 42 of the lamp holder 40. The other end of 
the spring 60 abuts against a pole of the battery cells 30. Therefore, the 
first contact 51 of the lamp 50 is connected electrically to the battery 
cells 30. 
To assemble the telescopic shaft magnetic retriever 10 of this embodiment, 
the battery cells 30 are loaded in the open end portion 211 of the battery 
holder 21. The open end portion 211 which is formed with external screw 
threads is then engaged threadedly with the internally threaded end 
portion 221 of the tubular sleeve 22. The lamp 50 is then inserted through 
the enlarged hole section 421 into the accommodation chamber 42 of the 
lamp holder 40. The first contact 51 and the second contact 52 pass 
through the through holes 43 and 43a, respectively. The axial extension 61 
of the spring 60 is inserted into the through hole 43 to couple closely 
with the first contact 51 of the lamp 50 and to fix the lamp 50 in the 
chamber 42. The second contact 52 passes through the through hole 43a and 
is then bent to form an L-shape, consisting of an axial portion 521 and a 
radial portion 522. The radial portion 522 of the second contact 52 
extends into the radially extending slot 47 in the shoulder 46 of the lamp 
holder 40 and extends partially out of the lamp holder 40. Finally, the 
lamp holder 40 and the tubular sleeve 22 are assembled together by 
threading the tubular section 40b of the lamp holder 40 into the 
internally threaded end portion 222 of the tubular sleeve 22. Since the 
barb member 49 is flexible and is capable of being bent radially and 
inwardly, the enlarged and tapered free end portion 493 rebounds from the 
internal screw threads of the end portion 222 when the lamp holder 40 is 
being threaded into the tubular sleeve 22. Moreover, the inclined outer 
side surface 493a assists the lamp holder 40 when the latter is being 
inserted into the tubular sleeve 22 during assembly of the lamp holder 40 
and the tubular sleeve 22. After the enlarged and tapered free end portion 
493 has been located within the annular groove 224 in the tubular sleeve 
22, the barb member 49 springs back. Thus, one end of the spring 60 bears 
against the battery cells 30, and assembly of the magnetic retriever is 
completed. 
When the lamp 50 is turned on, as shown in FIG. 3, the first contact 51 of 
the lamp 50 is electrically connected with one pole of the battery cells 
30 by means of the spring 60. The radial portion 522 of the second contact 
52 is electrically connected with the other pole of the battery cells 30 
by means of the conductive tubular sleeve 22 and the conductive battery 
holder 21. The two contacts 51 and 52 of the lamp 50 and the battery cells 
30 constitute an electric circuit, thereby permitting activation of the 
lamp 50. The transparent lamp holder 40 allows passage of light emitted 
from the lamp 50. With the aid of the magnet 70 and the telescopic shaft 
20, the retriever can be used to retrieve things from inaccessible places 
in the dark. 
Referring to FIG. 4, to turn the lamp 50 off, the lamp holder 40 is 
slightly rotated relative to the tubular sleeve 22 to move the tubular 
section 40b outwardly away from the tubular sleeve 22. Accordingly, the 
radial portion 522 of the second contact 52 is separated and is 
electrically disconnected from the end surface of the conductive tubular 
sleeve 22. Therefore, the lamp 50 is deactivated. In this situation, 
however, whether or not the lamp 50 is activated, the telescopic shaft 20 
can be extended for retrieving things. In other words, the lamp 50 is 
switchable without extending or collapsing the telescopic shaft 20. 
Moreover, when the tubular section 40b is rotated away from the tubular 
sleeve 22, the radially extending inner side surface 493b of the enlarged 
and tapered free end portion 493 is capable of being confined within the 
sleeve 22, thus preventing removal of the transparent lamp holder 40 from 
the tubular sleeve 22. Therefore, the various components of the magnetic 
retriever are connected securely to each other. 
With this invention thus explained, it is apparent that numerous 
modifications and variations can be made without departing from the scope 
and spirit of this invention. It is therefore intended that this invention 
be limited only as indicated in the appended claims.