Pneumatically driven descaling tools

A hand-held pneumatic impact tool, comprising:

• a generally cylindrical housing sized for manual gripping and having tool component coupling means at each end for selectively attaching an interchangeable tool component thereto;
• a pneumatically powered tool actuator assembly located in said housing and including a reciprocating type piston member mounted in an outer cylinder member affixed to an inner surface of said housing, an inner rear end section located between both said outer cylinder member including said piston member and said pneumatic valve, and a first air passage extending from said pneumatic valve between said inner surface of said housing and an outer surface of said inner rear end section and said outer cylinder member,
• said piston member further comprising a double acting piston member including a generally cylindrical body member having an enlarged rear portion facing said inner rear end section and having a peripheral surface defining a first shoulder region thereat, an axial bore in said piston member open to said inner rear end section and at least one transverse opening in said piston member at a forward section of said axial bore, said outer cylinder member having at least one opening therein in relatively close proximity to said at least one transverse opening in said piston member, and an enlarged forward portion facing said tool head and having a peripheral surface thereat defining a second shoulder region, the space between said first and second shoulder regions defining a second air passage for driving said piston member, said first and second air passages being connected by said at least one opening in said outer cylinder, whereby compressed air from said pneumatic valve is supplied via said first air passage to said bore of said piston member through said at least one transverse opening therein and said at least one opening in said outer cylinder causing the piston member to be driven in a forward direction until said at least one transverse opening is blocked by the forward portion of said outer cylinder, whereupon air being fed to said second air passage is now be supplied to said first shoulder region of said piston member driving it in a rear direction, a repetitive forward and rear motion thereby being imparted to said piston member and said work tool;
• a plurality of different type detachable and interchangeable tool heads connectable to one end of said housing, each of said tool heads including a respective work tool selected from a group consisting of descaling, chipping, chiseling and abrading tools and being driven by a forward portion of said piston member;
• and
• a readily removable hand actuated pneumatic valve coupled to the other end of said housing for supplying compressed air to said tool actuator assembly for powering said piston member,
• whereby a set of interchangeable impact tool components can be assembled on demand to provide a plurality of tool configurations for performing a plurality of different work functions.