Fishing tool for magnetic objects

A tool for fishing magnetic objects through a wall includes a body portion that has a cavity formed therein. An electromagnet is secured in the cavity and is connected to a variable power source that is adapted to selectively activate the electromagnet. A pair of lines are secured to the top of the body portion so that the same can be raised or lowered a predetermined distance. The body portion includes a slot that extends into the same from the top thereof. The slot is adapted to retain an end of a fish tape therein.

BACKGROUND OF THE INVENTION 
The present invention relates to a tool for use in fishing electrical wires 
through a wall and, more particularly, to such a tool that utilizes an 
electromagnet for selectively attracting magnetic objects such as fish 
tape. 
Electricians and other installers of electrical fixtures and telephones in 
dwellings, offices and commercial buildings spend a significant amount of 
time running electrical conduit or wire through walls. The running of wire 
is necessary to establish the connection between a fixture and a 
corresponding power source. In some instances, a length of fish tape is 
first inserted through a hole in a wall and positioned adjacent a 
different hole some distance away. The wire to be installed is then 
secured to the one end of the fish tape. Thereafter, the other end of the 
tape is pulled through the wall so that the wire is drawn through the 
same. 
It is often difficult to insert either the fish tape or electrical wire 
through one hole in a wall and manipulate the same so that one end of the 
tape or wire can be positioned adjacent another second hole. In 
recognition of the aforementioned problem, magnetic fishing tools have 
been developed that aid in the insertion of the fish tape and/or 
electrical wire through the wall. 
U.S. Pat. No. 3,078,073, for example, discloses an electrical wire finder 
that includes a conductor holder and a sensor made of magnetizable 
material. In use, the conductor holder, with a conductor secured thereto, 
is inserted into a hole in a wall. Thereafter, the sensor is lowered from 
an area where the connecting cable or wire is located, via a flexible 
line, to the vicinity of the conductor holder. The conductor holder has a 
magnet secured thereto. Accordingly, the conductor holder and sensor are 
attracted to one another. The operator can then raise the flexible line to 
carry the conductor to the connecting cable in order to establish the 
required electrical connection. 
A problem associated with this prior art device is that the conductor 
holder has a permanent magnet secured thereto. Accordingly, as it is 
inserted into the wall it attracts anything that is made of magnetic 
material. This interferes with the insertion and positioning of the 
conductor holder. Furthermore, since the line secured to the sensor is 
flexible, the sensor cannot be pushed upwardly through a wall. More 
specifically, if the holder and attached conductor are located adjacent a 
first hole positioned above a second hole, the sensor could not be 
inserted through the second hole and up toward the first hole because the 
line has no structural rigidity. 
U.S. Pat. No. 3,971,543 discloses a tool for fishing electrical wires 
through walls that includes a magnetic sensor. One end of the sensor is 
connected to a length of chain while the other end has a fastener member 
which is secured to a line or wire. In use, a cylindrical member, which 
houses a permanent magnet therein, is inserted through a hole in the wall 
to attract the sensor assembly which is suspended within the wall. Once 
again, this device is only useful in allowing an operator to position the 
line or wire from an upper location to a lower location as the chain has 
no structural rigidity. Additionally, the magnet secured to the 
cylindrical housing cannot be selectively energized or deenergized. 
U.S. Pat. Nos. 4,527,775 and 4,572,561 also disclose devices for installing 
wire or conduit. However, these devices are relatively complex and 
unwieldy. 
SUMMARY OF THE INVENTION 
The present invention is designed to overcome the deficiencies of the prior 
art discussed above. It is an object of this invention provide a fishing 
tool that facilitates the installation of wire or other conduit behind a 
wall. 
It is a further object to provide a fishing tool that allows a mechanic to 
insert fish tape up a wall through insulation or similar material. 
It yet another object of the invention to provide such a tool that includes 
an electromagnet which can be selectively activated and/or deactivated. 
In accordance with the illustrative embodiments, demonstrating features and 
advantages of the present invention, there is provided a tool for fishing 
magnetic objects through a wall that includes a body portion that houses 
an electromagnet therein. The electromagnet is connected to a battery via 
a pair of wires so that the former can be selectively activated. In the 
preferred embodiment, the body portion has a slot for retaining an end of 
a fish tape therein. The body portion can be raised or lowered in a wall 
by the wires that connect the electromagnet to the battery, by a separate 
line secured to the body portion or by a fish tape secured in the body 
portion. 
Other objects, features and advantages will be readily apparent from the 
following detailed description of a preferred embodiment thereof taken in 
conjunction with the drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings in detail wherein like reference numerals 
have been used throughout the various figures to designate like elements, 
there is shown in FIG. 1 a tool for fishing magnetic objects through a 
wall constructed in accordance with the principles of the present 
invention and designated generally as 10. 
The fishing tool 10 includes a body portion 12 having a cavity 14 formed in 
the bottom thereof (see FIG. 2). A slot 16 extends into the top of the 
body portion 12. The slot is preferably offset from the cavity 14. A pair 
of screw holes 18 and 20 extend into the top of the body portion 12. 
Extending into the side of the body portion 12 are set screw apertures 19 
and 21 which receive set screws 22 and 24. In the preferred embodiment, 
the body portion 12 is cylindrically shaped. However, the body portion can 
be a variety of other shapes such as rectangular or bullet shaped. Body 
portion 12 preferably has a diameter of approximately 7/8" and is 2" long. 
It can be made of stainless steel, other high quality alloys or plastic. 
In the preferred embodiment, a ring member 23 is secured to the top of the 
body portion 12 (see FIG. 1). A length of string 25 or the like is 
preferably secured to the ring member 23 as shown in FIG. 4. 
An electromagnet 26 is secured in the cavity 14. A pair of thin conductive 
lines 27 and 29 extend from the upper portion of the electromagnet. Each 
of the lines extends through the body portion and is positioned in a 
corresponding hole 18 and 20. Screws 32 and 33 provide terminals to 
connect the electromagnet 26 to a variable direct current battery or other 
power source 34 via a pair of wires 28 and 30 as illustrated in FIG. 1. 
More specifically, each wire 28 and 30 has one end secured around a 
corresponding screw 32 and 33. The wires must be of equal or greater 
length than the distance the fishing tool 10 must extend as more fully 
described below. The power supply 34 selectively energizes the 
electromagnet 26 when an activation switch, well known in the art, is 
triggered. A holder (not shown) made of metal or high impact plastic can 
be utilized to house the power source or battery. The holder would 
preferably include a belt clip and/or wrist strap for securement to the 
worker. 
To facilitate an understanding of the principles associated with the 
foregoing apparatus, its operation will now be briefly described. Upper 
and a lower holes 36 and 38 are formed in a wall 40 as illustrated in FIG. 
4. The body portion 12 of the fishing tool 10 is inserted through the 
upper hole 36 and is lowered downwardly toward the lower hole 38. During 
the insertion of the body portion, the electromagnet 26 secured therein is 
not energized. Once the electromagnet is in the vicinity of the lower hole 
38, it is energized and the end of a fish tape 42 is inserted through the 
lower hole until it is adjacent the electromagnet 26. When the tape 42 
approaches the electromagnet, it will be drawn thereto and this is sensed 
by the workman. 
The fishing tool 10, together with the fish tape 42, is then pulled up 
through the wall toward the upper hole 36. This can be achieved by 
grasping the string 25 and pulling the same away from hole 36 until one 
end of the fish tape extends through the upper hole 36. The other end of 
the fish tape extends through the lower hole 38. Since the battery is 
preferably of the variable direct current type, the strength of the 
electromagnet can be increased or decreased as required. After an end of 
the fish tape 42 is drawn through the upper hole 36, a wire or other 
conduit is attached thereto. Thereafter, the end of the fish tape adjacent 
the lower hole 38 is pulled away from the wall so that the wire or other 
conduit is properly fished for subsequent electrical connection. 
The fishing tool 10 can also be utilized to insert a length of wire or 
other conduit from a lower level to an upper level. This is achieved by 
first inserting the end of the fish tape 42 into the slot 16 in the upper 
portion of body portion 12 as shown in FIG. 3. The end of the fish tape is 
secured in the slot by the set screws 22 and 24 threaded into the screw 
apertures 19 and 21. Once the fish tape 42 is in place, the body portion 
12 is inserted up through the lower hole 38 by grasping the fish tape and 
feeding it up along the wall (see FIG. 5). Since the fish tape 42 has some 
structural rigidity, the body portion can be fished up the wall until it 
is in the vicinity of the upper hole 36. Moreover, the rigidity of the 
fish tape allows it to pass through insulation material or other similar 
barriers as it travels up the wall. 
Once the body portion 12 is in the vicinity of the upper hole 36, a second 
fish tape 48 or other magnetic material is inserted into the hole 36. 
Thereafter, the electromagnet is energized in the manner described above. 
The second fish tape 48 is then attracted to the electromagnet 26. 
Thereafter, the second fish tape 48 is pulled through and away from the 
upper hole 36 which in turn draws the body portion and the attached first 
fish tape 42 through the upper hole. This allows the operator to attach a 
wire to the first fish tape. Thus, when the end of the first fish tape 42 
that extends from the lower hole 38 is pulled away from the wall, the 
other end, which is secured to the wire or other conduit to be fished, is 
drawn down the wall through the upper hole 36 and out the lower hole 38. 
The present invention may be embodied in other specific forms without 
departing from the spirit or essential attributes thereof and accordingly 
reference should be made to the appended claims rather than to the 
foregoing specification as indicating the scope of the invention.