1. Field of the Invention
This invention relates to blade-type drill bits, and more particularly to a drill bit which is adapted to be detachably and pivotably linked to a wire fishing adapter for pulling wire through the hole bored by the drill bit.
2. Description of the Prior Art
Installation of hidden wiring for various low-voltage electrical systems, such as telephones, public address systems, speaker systems for stereo components and the like, within existing walls of buildings, requires one or more holes to be drilled in the walls of the building through which the wiring is routed. This is typically accomplished by means of a drill, usually of the blade-type variety.
After the drill has bored through the various elements comprising the internal reinforcing and supporting structure of the wall, the wire or wire cable must be pulled or "fished" through the passageway bored in and through the wall.
One method used rather extensively for fishing the wire through the passageway drilled in the wall was to utilize a "fish tape." A fish tape is a reel of a length of relatively flat spring steel. The end of the fish tape is looped to form an eyelet. The fish tape is used quite simply by first inserting the eyelet end of the fish tape into the passageway. The fish tape is then simultaneously unreeled and pushed into the passageway. When the eyelet end of the fish tape reaches the opposite end of the bored out passageway in the wall, the wire is fixedly secured to the fish tape by passing it through the eyelet and wrapping the wire about its own body. The fish tape is then reeled in, thereby fishing the wire through the bored out passageway in the wall.
This method is especially suitable for relatively short runs. However, for long passageway runs, it becomes increasingly difficult in most walls, if not truly impossible, to direct the fish tape through the passageway to the other end thereof. The reason for this difficulty becomes clear when one considers how most building walls are constructed.
Most building walls are constructed using a pair of plaster-formed sheets or are faced with plasterboard sheets with two by four wooden studs sandwiched between the sheets on edge. The studs are spaced apart by some distance, generally in the order of 15 to 18 inches apart. In boring a passageway through and along the inside of the wall, it is necessary to bore through several studs.
In pushing the fish tape through the holes in the studs, alignment problems arise, thereby making it difficult to span long passageway runs through walls having this type of construction.
Another method used in the prior art eliminated the use of the fish tape. This was accomplished by drilling a hole through the body of the blade-type drill bit to allow the wire to be secured to the drill bit itself by looping the wire through the hole. When the drill bit is withdrawn from the passageway bored in the wall, the wire is fished through the passageway at the same time. However, utilization of this method is not without its problems.
For example, the wire loop which was formed as the wire was passed through the hole in the drill bit in many cases tends to form a wire bundle having a larger diameter than that of the passageway bored out by the drill bit. When this occurs, the wire cannot be pulled through the passageway.
Further, the looped portion of the wire once it has been fished through the passageway, must be cut off because substantial portions of the wire may be severed during the feed through process. Consequently, since the integrity of this portion of the wire is questionable, it must be removed before the wire is coupled to another group of wires or electrical/electronic components.
Another problem which oftentimes developes using the hole in the drill bit is that in fishing relatively soft copper wire, a sufficient shearing action may develop to sever the wire being pulled through the passageway.
It is due primarily to the above mentioned problems, as well as numerous other, which led to the discovery of the present invention hereinafter disclosed.