Patent Application
20140131644
The present invention relates to a multi-purpose prying tool, commonly referred to as a Halligan bar.
Prying tools are commonly used by firefighters for a variety of purposes, including breaking through doors or other entry points to enter buildings. Some of these types of tools have come to be known as Halligan bars in the firefighting industry, and are typically a long bar having a forked blade on a first end, and a solide blade and tapered pick on a second end. This tool is often carried with an axe with the set commonly referred to as “irons.”
Referring to
For this reason, it is known that individuals sometimes file down these shoulders to create flatter surfaces for easier striking by the axe head. However, this creates sharp corners at the shoulder that cause stress concentrations leading to cracking or fracturing of the tool.
Therefore, it would be advantageous to have a halligan bar that can be struck by an axe or other impact tool to easily wedged in between a door and door jamb.
In an aspect of the invention, this is accomplished by creating a dimpled shoulder on the forked end of the tool, which discourages the axe head from glancing off while maintaining the strength of the forked end.
Further features and advantages of the present invention will be better understood by reference to the following description, which is given by way of example and in association with the accompanying drawings, in which:
Referring to
In use, the pick 230, which is generally cone-shaped ending in a sharp point, is typically forced into a shackle (or eye) of a padlock or hasp and twisted or pried to break it free. It can also be driven into a roof to provide a foothold for firefighters engaged in vertical ventilation.
The solid blade 220 or forked blade 210 can be used to quickly pry open a door by inserting in between a door and door jamb, and prying the door loose. The solid blade 220 is formed as a generally rectangular implement with a single cutting surface 221. In contrast, the forked blade 210 includes a split 211 down its middle to form two smaller blades 212, and has other uses, such as to shut of gas meter valves.
Additionally, the fork 210 has shoulders 250 (see
The protrusion 270 and dimple 260 are formed with smooth curves so that no sharp corners exist, which prevents stress concentrations from forming. Sharp corners lead to high stress values in localized areas, and after repeated impact from a striking tool, the material at the root of the corner becomes overstressed and can crack. This is important since users will often use an axe or other striking tool to strike the shoulder 250 of the forked end to wedge it further into prying position.
The present invention thus improves upon prior art devices, which have flat sloping surfaces that tend to encourage the striking tool to glance off the shoulder. The dimpled shoulder of the present invention discourages this glancing effect, since only a small portion of the protrusion 270 faces away from the shaft 202 (eg. the outwardly facing portion of the protrusion 270).
While the invention has been described in the specification and illustrated in the drawings with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention as defined in the claims. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. For example, one or more of the pick, blade, or fork can be replaced with other types of cutting or breaking elements in any variety of combination thereof. Therefore, it is intended that the invention not be limited to the particular embodiment illustrated by the drawings and described in the specification, but that the invention will include any embodiments falling within the description of the appended claims.
