Abstract: A utility knife includes a carrier slidably received in a housing and having one or more orifices, and a blade disposed between the carrier and the housing. A latch has one or more pins extended through the orifices of the carrier, to engage into the blade and to retain the blade to the carrier, and for allowing the blade to be moved relative to the housing by the carrier. A spring may bias the latch against the carrier, to engage the pins of the latch into the blade. A button may selectively disengage the pins of the latch from the blade, to allow the blade to be removed from the carrier and to be replaced with new blades.

Abstract: A knife includes a blade holder slidably received in a housing for holding a blade with one or more spring-biased protrusions. The housing has a passage for slidably receiving one or more spare blades. One or more springs are received in the housing and engaged with the spare blades for forcing the spare blades toward of the blade holder when the blade is removed from the blade holder. The blades may thus be exchanged without disassembling the housing. A button is slidably received in the housing and has one or more legs for disengaging the protrusions from the blades.

Abstract: A knife includes a blade support device slidably received in a housing for supporting a blade and having a spring limb. The spring limb includes one or more catches engaged with the blade for securing the blade to the blade support device. A button is slidably received in the housing and has one or more spring legs for disengaging the catches from the blade and for allowing the blade to be engaged into and disengaged from the blade support device without removing the blade support device from the housing. A knob may move the blade support device along the housing.

Abstract: A plier device includes two handles each having an open channel formed in one end, and a pair of rods pivotally secured together at a middle pivot pin. The rods include two ends each having a pair of jaws. The jaws each includes a rib engaged into the channels of the handles for detachably securing the tool device to the handles. The handles each includes a pair of flanges extended inward of the channel, the jaws each includes a pair of opposite grooves for receiving the flanges of the handles. The handles each has a spring-biased projection engaged with the jaws.

Abstract: A retractable driving tool includes a driving stem slidably received in a handle and includes a number of teeth. A pawl is slidably engaged in the handle and is biased to engage with the teeth of the driving stem and for securing the driving stem to the handle and for allowing the driving stem to be moved relative to the handle when the pawl is moved against a spring. A spring is disposed between the rear end of the handle and the driving stem for moving the driving stem forward and outward of the handle. A slide is engaged between the spring and the driving stem.

Abstract: A tool device includes a pair of handles each having a chamber formed by a pair of panels and each having a pin secured in the middle portion. A tool member includes two ends each having a tool portion and includes a middle portion engaged with a fastener which is engaged with the ends of the handles for pivotally coupling the handles and the tool member together. The distance between the fastener and the pins is shorter than the tool portions such that the pins may be forced to engage with one of the tool portions for allowing the other tool portion to be used.