Electrician's fish tape locator system

A fish tape locator system for use by an electrician comprises a transmitter assembly and a receiver. The system is used by the electrician as an aid in running electric wire through a conduit. The transmitter assembly has a mounting means for attachment to a terminus of the conduit, a switch associated with the mounting means and in alignment with the conduit terminus to be activated by an end of the fish tape as it exits the conduit terminus, and an electronic transmitter coupled to the contact switch to transmit a signal when activated. The receiver worn by or in the general vicinity of the electrician receives the signal from the transmitter and alerts the electrician to the fact the fish tape end has reached the conduit terminus.

This invention relates to a locator system. More particularly, it relates 
to a locator system used by an electrician to determine when a fish tape 
being forced through a conduit has reached the conduit's terminus. 
Industrial plants and commercial establishments have a great demand for 
electrical service. These businesses typically have electric wires running 
through ceiling dead spaces and walls. The wires are normally run through 
metal or plastic conduit that range from one-half inch to two inches in 
diameter. More than one wire is often run through the conduit. The 
conduits protect the electric wires from accidental damage and contain the 
wires in a confined space. Electric wires in many businesses are 
continually rerouted and added to as business needs dictate. The conduits 
also facilitate this process. 
It is not unusual for an electric wire to extend several feet, e.g. up to 
one hundred feet from one junction box to another junction box or outlet. 
The conduits which are used to contain the wire may be in a straight line 
or may contain one or more bends. Threading a wire through the conduit can 
prove challenging. An electrician's fish tape is commonly used to aid the 
process. The fish tape is a semi-rigid though flexible thin metal tape 
which is wound on a reel. One end of the tape is hook-shaped. In use, the 
electrician inserts the hook-shaped end of the fish tape into the conduit 
and then forces it through the conduit as the reel is unwound. The 
semi-rigid nature of the fish tape allows it to be pushed through the 
conduit while its flexible nature allows it to pass around curves or even 
right angle bends in the conduit. Eventually, the hook-shaped end of the 
fish tape reaches the second end of the conduit. The electric wire is 
simply secured to the hook-shaped end and pulled along by the fish tape as 
it is being rewound onto the reel. The electric wire is released from the 
fish tape after the fish tape is fully retrieved. 
A certain degree of skill is required for the electrician to initially 
force the fish tape through a long conduit, especially one that has bends. 
The bends provide a point where the fish tape's travel can be obstructed. 
The electrician may sense that there is an obstruction based on an 
estimate of fish tape length which has already been forced into the 
conduit. Other times, the electrician will only know there is an 
obstruction by walking to the conduit terminus and visually detecting the 
absence of the fish tape end. This, of course, is time consuming and can 
be frustrating. Several such trips may be needed before the fish tape has 
been manipulated past a bend and truly has reached the conduit's terminus. 
In accord with a need experienced by many electricians, there has been 
developed a fish tape locator system. The system is easy to use and 
reliably alerts the electrician as to when a fish tape end has fully 
travelled through a conduit and has reached the conduit's terminus. 
SUMMARY OF THE INVENTION 
An electrician's fish tape locator system comprises a transmitter assembly 
and a receiver. The system is used to determine when a fish tape forced 
through a conduit has reached a terminus. The transmitter assembly has a 
mounting means for attachment to the conduit terminus, a switch mounted 
adjacent to the conduit terminus and in alignment therewith, and an 
electronic transmitter coupled to the contact switch. The system also 
comprises a receiver worn or placed in the general vicinity of the 
electrician. The electrician initially forces the fish tape through the 
conduit and if need be manipulates it around bends in the conduit until it 
reaches the conduit terminus and activates the contact switch. A signal 
which is transmitted by the transmitter and received by the receiver, 
alerts the electrician that the fish tape end has reached the conduit 
terminus.

DETAILED DESCRIPTION OF THE INVENTION 
With reference to FIGS. 1 and 2, there is shown the fish tape locator 
system 10 of the invention. The system comprises a transmitter assembly 11 
and a receiver 12. As shown, it is used by an electrician as an aid in 
forcing a fish tape 13 through a conduit 14 and alerting him as to when an 
end of the fish tape has reached a conduit terminus 15. As shown in FIG. 
2, the end of the fish tape has reached the conduit terminus and as 
discussed in detail in the following paragraphs, the transmitter assembly 
11 emits a signal which is received by the receiver 12 worn by the 
electrician. 
Still with reference to FIGS. 1 and 2, the conduit 14 is several feet long. 
It is shown with four right angle bends. The conduit is connected at a 
first end to a junction box 16 and at a second end to another junction box 
17. Conventional attaching means are used for this purpose. The 
electrician is shown in the process of feeding the fish tape 13 through 
the junction box 16 and the conduit 14. The fish tape 13 is wound on a 
reel 18. Such fish tape reels are commercially available and widely used 
by electricians. The fish tape end has a hook-like member on which an 
electric wire can be securely attached at the junction box 17 and pulled 
back through the conduit. The farthest two bends create a potential for 
the fish tape to be obstructed in its travel. The point of obstruction is 
sufficiently far that the electrician may very well think the fish tape 
has reached the conduit terminus. However, with the fish tape locator 
system of the invention, he is aware that the fish tape is merely 
obstructed and that he must manipulate the fish tape to cause it to turn 
the bend and continue in its travel. 
As best seen in FIG. 4, the transmitter assembly 11 comprises a bracket 20, 
a contact switch 21 and an electronic transmitter 22. The bracket 20 is a 
mounting means for the contact switch 21 to ensure it is in alignment with 
the conduit terminus. The bracket is U-shaped with a first leg 23 having a 
slot 24 which is dimensioned to slip over the conduit on the outside of 
the junction box. A friction fit is sufficient to semi-permanently hold 
the bracket in position during use and readily remove it once its function 
is completed. A second leg 25 of the bracket is used to hold the contact 
switch 21 adjacent the conduit end and in close proximity to it. It has a 
hole through which a shaft 26 of the contact switch extends. The cross-leg 
27 of the bracket has a length such that the second leg 25 and the contact 
switch 21 are from about one-half inch to about three inches from the 
conduit terminus and aligned therewith. Other bracket structures can as 
well be used for the purpose of mounting the contact switch adjacent the 
conduit terminus. 
The contact switch 21 includes a striker plate 28 which when touched with 
sufficient force will move the shaft 26 which in turn trips the switch 21. 
Such switches are commercially available. The switch 21 is coupled to the 
electronic transmitter 22 by a jack plug 29. 
The electronic transmitter 22 has a housing 30, a jack plug receptacle 31 
to receive the jack plug 29, and a means within the housing to transmit a 
signal in response to activation of the contact switch. As shown, the 
housing 30 of the transmitter 22 has a hole 32 on an upper flange 33 which 
is used to conveniently hook onto a screw head on the junction box 17. A 
switch 34 and a LED 35 are optionally provided to indicate when the 
transmitter is in an operational mode. 
The transmitter assembly 11 can take other forms. For example, a housing 
with an attaching means on one wall to connect directly to the conduit 
terminus and the contact switch mounted within the housing and positioned 
to receive a force from the fish tape end is possible. An electronic 
transmitter coupled to the contact switch is mounted within the housing or 
on an outside wall of the housing. 
As shown in FIG. 3, the receiver 12 is constructed to be worn on the belt 
of the electrician. It has a housing 36 and belt clip 37. Within the 
housing 35 is a receiving mechanism for detecting a signal transmitted by 
the electronic transmitter 22 and converting it into a noticeable form. 
For instance, the receiver is able to emit sound, light or vibration to 
alert the electrician that the contact switch has been activated. 
Optionally, a LED 38 is on the housing 35 of the receiver 12 and is 
operably connected to a power source such as a battery to indicate to the 
electrician that it is in the receiving mode. A switch 39 is used to turn 
off the receiver when not used to conserve the battery. The receiver can 
as well be made to be free-standing or have a hanging hook on its housing 
such that it can be placed in the general vicinity of the electrician. 
In operation, the electrician initially mounts the transmitter assembly at 
the conduit's terminus. After activating his receiver, he inserts the end 
of the fish tape into the conduit and forces it to travel through the 
conduit. If an obstruction has been reached and no signal is emitted, the 
electrician will know that he must continue to manipulate the fish tape 
until it travels further through the conduit. Eventually the fish tape end 
exits the conduit terminus and touches the striker plate of the contact 
switch. This causes the electronic transmitter to emit a signal which in 
turn is received by the receiver and the electrician is assured that the 
fish tape end extends pass the conduit's terminus. He then walks to the 
conduit terminus to securely attach an electric wire to the fish tape end, 
returns to the original site, and winds the fish tape back onto its reel. 
The electric wire is pulled through the conduit by the fish tape, cut and 
connected in a conventional fashion. 
While the invention has been described in detail, it should be understood 
modifications can be made. For example, a light sensing switch or other 
known switches which are capable of detecting the fish tape end can be 
used. All changes of an obvious nature are considered within the scope of 
the appended claims.