FIELD: concrete structure perforating.
SUBSTANCE: invention relates to a device for perforating a concrete structure or rock with rotation of a cylindrical drill bit, as well as for extracting a core from a concrete structure when taking samples for strength testing. A core drilling device with a one-touch locking function of the drill bit contains a polygonal connecting protrusion connected to one side of the drill bit, a plurality of locking grooves, respectively made at the corners of the polygonal connecting protrusions on their outer periphery, a retarding connector, a blocking body, mounted in one piece outside the spindle which is made open to the outside of the retarding unit and with a pin hole extending from its one peripheral outer side to the other peripheral outer side, and a locking pin that is resilient within the pin hole with a spring interposed therebetween and is inserted into a locking groove of the retard connector that is inserted into a polygonal connection hole formed on the spindle to maintain automatic locking of the drill bit and retard block. The locking pin comprises a guide part having a pushing projection formed thereon, a gripping part and a locking part, which are sequentially made with multiple steps. The guide portion is formed to pass through a spring holder that is properly seated at the linear end of the pin hole and inserted into the pin hole. The gripping part is gripped by the spring holder and prevents the locking pin from separating from the outside. The spring is resiliently installed between the gripping part and the pressure ledge.
EFFECT: prevention of vibrations of the end section of the drill bit up and down, increase of work productivity and prevention of accidents, simplification and convenience of use.
6 cl, 12 dwg
