Hole saw connecting mechanism

A hole saw connecting mechanism, comprising a rotary shaft assembly and a hole-opening assembly;

• an upper end of the rotary shaft assembly is detachably connected to the hole-opening assembly, and a lower end of the rotary shaft assembly is configured to be connected to a driving assembly that drives the hole-opening assembly to rotate;
• wherein the rotary shaft assembly comprises a drill bit limiting sleeve and a limiting mechanism;
• the hole-opening assembly comprises a quick connecting head, a pilot drill bit, and a cylindrical hole saw;
• the limiting mechanism comprises a limiting steel ball, a sliding sleeve, and an upper cover;
• an upper end of the drill bit limiting sleeve is provided with a first accommodating cavity in which a lower end of the quick connecting head is mounted;
• an ejection mechanism is also provided in the first accommodating cavity;
• threads at an upper end of the quick connecting head are connected to the cylindrical hole saw;
• an inner circular sidewall of the sliding sleeve is divided into an upper inner circular sidewall and a lower inner circular sidewall;
• a diameter of the upper inner circular sidewall is larger than a diameter of the lower inner circular sidewall;
• a first limiting hole is provided penetrating through opposite sidewalls of the drill bit limiting sleeve at the upper end of the drill bit limiting sleeve corresponding to the first accommodating cavity, and the limiting steel ball is mounted in the first limiting hole;
• the quick connecting head is provided with a first positioning groove, and the limiting steel ball is limited within the first positioning groove;
• the upper cover is fixedly connected with the drill bit limiting sleeve;
• when the sliding sleeve is pulled downward away from the cylindrical hole saw along an axial direction of the drill bit limiting sleeve, the lower inner circular sidewall is driven to move below the limiting steel ball such that the upper inner circular sidewall is positioned corresponding to the limiting steel ball and thus no longer limits the limiting steel ball due to a larger diameter thereof compared with that of the lower inner circular sidewall, and so the limiting steel ball is allowed to move out from the first positioning groove and thus achieve an unlocked state of the quick connecting head, and the quick connecting head is allowed to be ejected by the ejection mechanism;
• when the sliding sleeve is reset to an original normal position through a reset assembly, the lower inner circular sidewall is driven upward such that the limiting steel ball is again abutted by the lower inner circular sidewall of the sliding sleeve, and so the limiting steel ball is being pushed back into the first positioning groove and thus achieve a locked state of the quick connecting head;
• the limiting steel ball moving in and out of the first positioning groove due to movements of the sliding sleeve along the axial direction of the drill bit limiting sleeve achieves said locked state and said unlocked state of the quick connecting head, such that the quick connecting head is capable to be locked or unlocked with respect to the drill bit limiting sleeve;
• the pilot drill bit is mounted on the quick connecting head or on the drill bit limiting sleeve through a collar assembly.