Abstract: A safety syringe includes an injection head, a plunger and a barrel. The ection head has a needle cannula mounted to a needle seat, with the needle seat attachable to a needle seat connector. The inner side of the rear end of the needle seat connector has stoppers that correspond to protrusions on the coupling portion of the plunger. The plunger has a plunger shaft connected by a conical section to a coupling portion that has a rubber gasket. The plunger shaft can be snapped off at the conical section after use, so as to completely disable the syringe. The safety syringe has a barrel for receiving the injection head portion and the plunger such that a liquid-tight chamber is formed to hold medicine or blood. The injection head is attached to the barrel through interlocking annular edges and grooves, and remains so attached during the withdrawal of fluid and during the injection phase.

Abstract: A retractable safety syringe has a hub at the end of its plunger which engages a needle carrier when the plunger is depressed so that the needle carrier can be withdrawn into the syringe along with the needle. To facilitate breaking off the plunger shaft, thereby trapping the spent needle within the syringe, there is a conically shaped flangible section between the plunger and the shaft which defines a sharp notch allowing the shaft to be broken off at any angle.

Abstract: A guard rail assembly for roads comprising a first post, a second post, a fixing frame, a connector, and a pair of guard plates. The first post is a hollow squared structure filled with foamed plastics therein and is detachable and inserted into a second post buried in the ground. The connector is a corrugated plate having continuous vertical bending mounted on the first post. The pair of guard plates have a shape corresponding to the connector. Each end of the guard plate is engaged with the connector and fixed thereon.