US 4,552,287 AGranted

Thermoplastic dispensing device

AssigneeMinnesota Mining and Manufacturing Company

InventorMichael M. Dziki

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Abstract

A device for dispensing molten thermoplastic material which an operator grips while using his thumb to press a solid block of the thermoplastic material through a sleeve and into a heated melting chamber from which the molten thermoplastic material is discharged through a nozzle. The device includes a bracket adapted to hold a second block of thermoplastic material in end-to-end relationship with a first block in the sleeve, and a heated barrier ring at the inlet to the melting chamber that restricts escape of the molten thermoplastic material through the sleeve; and may also include a slidable pressure plate between the block and an operator's thumb and/or a trigger-operated outlet valve between the melting chamber and nozzle.

Claims13

Dependent claims

In a device for dispensing molten thermoplastic material comprising a frame, a barrel member mounted on said frame and having an internal melting chamber communicating with an outlet opening through a nozzle, a sleeve with a through opening having one end secured at said barrel member and said opening communicating with the end of said melting chamber opposite said outlet opening, said sleeve being adapted to receive a block of solid thermoplastic material with one end portion of the block in the melting chamber and the block projecting through said sleeve, and means for heating said barrel member to melt the end portion of the block therein, said frame including a handle positioned so that an operator can grip the handle with the fingers of one hand while applying pressure with the thumb of that hand directly toward the end of the block opposite the melting chamber to press the block through the sleeve and into the melting chamber to force molten thermoplastic material out said outlet opening, the improvement wherein:

said device further includes holding means at the end of said sleeve opposite said melting chamber adapted for holding a second block of solid thermoplastic material outside said sleeve in aligned end-to-end relationship with a said block of thermoplastic material in said sleeve while affording pressure by the thumb of an operator to press the second block into the sleeve and melting chamber, said holding means comprising spaced opposed resiliently flexible gripping parts projecting towards said handle, said gripping parts having opposed distal surfaces spaced so that the second block can be transversely pressed therebetween to resiliently move the gripping parts away from each other and afford movement of the block therebetween, and having opposed inner surfaces adapted to engage the seocnd block of polymeric material along its opposite side surfaces to hold the second block in alignment with the block in said sleeve, while affording movement of the second block and the thumb of the operator between said gripping parts to move the seoond block toward said sleeve.

A device for dispensing molten thermoplastic material comprising a frame, a barrel member mounted on said frame and having an internal melting chamber communicating through a valve assembly with an outlet opening through a nozzle, a sleeve with a through opening having one end secured to said barrel member and said opening communicating with the end of said melting chamber opposite said outlet opening, said sleeve being adapted to receive a block of solid thermoplastic material with one end portion of the block in the melting chamber and the block projecting through said sleeve, and means for heating said barrel member to melt the end portion of the block therein, said frame including a handle positioned so that an operator can grip the handle with the fingers of one hand while pressing the block through the sleeve and into the melting chamber to force molten thermoplastic material out said outlet opening, said valve assembly including means for opening said valve assembly when the pressure of molten thermoplastic material in said melting chamber exceeds a predetermined amount and means for closing said valve assembly when the pressure of molten thermoplastic material in said melting chamber drops below said predetermined amount and said device including trigger means adapted to be manually activated by an operator to override said means for closing said valve assembly and afford dispensing molten thermoplastic material with a force against said block that is less than the force required to develop said predetermined amount of pressure in said melting chamber.

Dependencies are inferred from the claim text.

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Abstract

said device further includes holding means at the end of said sleeve opposite said melting chamber adapted for holding a second block of solid thermoplastic material outside said sleeve in aligned end-to-end relationship with a said block of thermoplastic material in said sleeve while affording pressure by the thumb of an operator to press the second block into the sleeve and melting chamber, said holding means comprising spaced opposed resiliently flexible gripping parts projecting towards said handle, said gripping parts having opposed distal surfaces spaced so that the second block can be transversely pressed therebetween to resiliently move the gripping parts away from each other and afford movement of the block therebetween, and having opposed inner surfaces adapted to engage the seocnd block of polymeric material along its opposite side surfaces to hold the second block in alignment with the block in said sleeve, while affording movement of the second block and the thumb of the operator between said gripping parts to move the seoond block toward said sleeve.