Hand-held motor-driven extruding device for dispensing a plastic substance

Claim 1

Hand-held motor-driven extruding device for dispensing plastic substances, such as sealing compounds, bonding agents, putty and the like, comprising a housing including a handle arranged to receive a motor drive, an axially elongated container for the substance to be dispensed, and means mounted on said housing and including a piston arranged to be moved by the motor drive reciprocably through and in the axially elongated direction of said container for dispensing the plastic substance out of said container, wherein the improvement comprises that said means includes at least one multi-part telescopic threaded spindle, said threaded spindle comprises an axially elongated first threaded spindle section fixed to said housing against displacement in the axially elongated direction of said container, and at least one second threaded spindle section telescopically movable relative to said first threaded spindle section in the axial direction of said first threaded spindle section, said first threaded spindle section has an axial length so that said at least one second threaded spindle section and said first threaded spindle section can be moved between a fully extended position and a fully retracted position whereby in the fully retracted position said first and second threaded spindle sections are located one inside the other, said piston is mounted on the end of said at least one second threaded spindle section more remote from the location where said first threaded spindle section is fixed to said housing, and said at least one second threaded spindle section is connected with said piston so that there is no relative rotation therebetween over the full axial travel of said piston between the fully retracted position and the fully extended position, said at least one second threaded spindle section includes at least two said second threaded spindle sections with one of said second threaded spindle sections being attached to said piston and the other said second threaded spindle section extending between the one said second threaded spindle section and said first threaded spindle section in the extended condition, the one of said second threaded spindle section being a sleeve-like member and said sleeve-like member having a diameter larger than that of the other said second threaded spindle section and said first threaded spindle section, said sleeve-like member having a first end at which said piston is located and an opposite second end, a generally radially outwardly projecting pin located at the second end of said sleeve-like member, an axially displaceable sleeve located radially outwardly from the other said second threaded spindle section in the extended condition and said sleeve having an axially extending slot therethrough, said pin on the second end of said sleeve-like member extends into said slot in said sleeve, a fixed sleeve secured to said housing and having a larger diameter than said axially displaceable sleeve so that said axially displaceable sleeve can fit within said fixed sleeve in the retracted condition of said device, a radially outwardly projecting pin formed on the end of said axially displaceable sleeve closer to said housing in the extended condition, said fixed sleeve having an axially extending slot therein, said pin on said axially displaceable sleeve extending into said slot in said fixed sleeve whereby in the extended condition one end of said axially displaceable sleeve is guided within said fixed sleeve and the other end of said axially displaceable sleeve is guided on said sleeve-like member forming the one said second threaded spindle.