Abstract: An adhesive injector has a piston inserted in a cylinder which is forwardly movable therein by a compressive force, the cylinder having a nozzle projecting from a front end portion thereof. The injector includes: a pair of holes defined adjacent each other in a rear end portion of the cylinder, a slit formed in the cylinder between the holes, a pin insertable through the holes, and cutout portions formed in the piston for engagement with the pin.

Abstract: A method of injecting adhesives (7) into cracks (2) of structures (1) for sealing the cracks, involves affixing injection pipes (4) on non-sealed surface portions of the structures at the cracks and connecting an adhesives injection device (10) to each one of the injection pipes. The injection devices are comprised of transparent cylinders having scales thereon graduated toward injection, nozzles (17) thereof, and of pistons (13) which can move linearly in both directions in the cylinders. The nozzles are respectively connected to the injection pipes after adhesives are drawn into the cylinders, and the pistons are moved toward the nozzles by compression, or pushing pressure, of rubber or springs to inject the adhesives into the cracks.