The present invention relates generally to an impact tool and more particularly to a pneumatic impact hammer for driving frost plugs into the block of an automotive engine. The blocks of most automotive engines include chambers for circulating a liquid coolant. If an engine is exposed to cold temperatures, any water within the chambers of the engine block will expand as it begins to freeze.
To release the pressure caused by the expanding water and thus prevent the block from cracking, the walls of many such engines include holes. In normal operation, these holes are blocked by "frost" or "expansion" plugs. The plugs normally act as part of the wall of the engine, maintaining the water within the proper chambers. If the water begins to freeze and expand, however, the water will force one or more of the frost plugs out of their holes. As a result, the pressure within the chambers of the engine block is often decreased to the point where the freezing water will not crack the block.
Frequently, the frost plugs in an automotive engine must be replaced. As discussed above, the frost plugs may be forced out by freezing water within the engine block. Even more commonly, the frost plugs corrode and no longer keep the coolant within the engine block.
Frost plugs are normally friction-fit into the holes of the engine walls. Since frost plugs normally function as part of the wall of the engine, the frost plugs must be tightly fitting within their respective holes of the engine wall.
Unfortunately, the presently available tools are poorly suited to meet the needs of a mechanic attempting to reinsert a frost plug into an automotive engine while the engine is in the vehicle. Typically, there is very little free space around the engine block. In addition, a substantial amount of force must be applied to the frost plug to insert it into the hole in the wall of the engine. Quite often, there is not enough room around the engine block for a mechanic to effectively swing a hammer and drive the frost plug into the engine. Consequently, a mechanic often must remove the engine from the vehicle so that there is enough space around the engine such that he may swing a hammer and pound the frost plug into place.
Other mechanical devices that may be available are inefficient in delivering force to the frost plug to safely and quickly drive the frost plug into the engine. In addition, many of such tools require manual power to drive the frost plug, rather than using a pneumatic source of power, which is commonly available to an automotive mechanic. Consequently, replacing a frost plug becomes a tiring and time consuming process.