Depth limiting device

#The present invention relates to a depth limiting device.

#A drill is a tool used for drilling a hole in a subject. For example, a bone drill can be used for drilling a hole in a bone in a surgery. When a drill is used for drilling a hole in a bone, a surgical doctor holds the drill and pressurizes for drilling. After the drill breaks through the bone substance completely, the electric drill falls through, and it is often difficult and even sometime impossible for the surgical doctor to stop pressurizing at the same time, so the drill may drill forwards continuously. In the drilling process, damages of tissues may be resulted; and if vessels and nerves existing in the heading direction of the drill are damaged, serious consequences may be resulted. In addition, measurement of the depth of the drilling hole is also needed for determination of a suitable screw after the hole drilling process is finished. Existing drills, however, only have a hole drilling function, so the surgical doctor needs to measure the drilling hole by inserting a depth measuring device in the drilled hole. There is a need for improved drill that will reduce the damages to tissues, vessels, and nerves during the drilling process.

#According to one embodiment, there is provided a depth limiting device for a drill that includes a main body; an axial braking structure, the axial braking structure being attached to the main body; and a limited shrinking structure, the limited shrinking structure surrounding a drill rod of the drill, being slidably attached to the main body, and being in a home position or a compressed position. The axial braking structure axially brakes the drill rod such that the drill rod moves together with the depth limiting device. When the drill rod enters into a subject, the limited shrinking structure is pressed against the subject, moves from the home position to the compressed position, and stops the drill rod from entering further into the subject.

#The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

#In the drawings:

#FIG. 1 shows a limited shrinking structure.

#In the Figures, the reference numerals have the followings designations: 1—drill rod, 2—drill rod bushing, 3—connecting sleeve, 4—retraction space, 5—first spring, 6—axial braking block, 7—cavity, 8—second spring, 9—trigger, 9.1—hand-held section, 9.2—horizontal section, 10—compression fitting surface, 11—limiting rod, 12—third spring, 13—handle, 14—protective plate, 15—main body, 15.1—front part, 15.2—rear part, 16—locking shaft, 17—first locking block, 18—linear motion cam, 19—rotary motion cam, 20—guide sleeve, 21—forth spring, 22—first connecting rod, 23—fifth spring, 24—bracket, 25—electric drill, 26—outer taper sleeve, 27—inner taper sleeve, 28—sixth spring, 29—U-shaped connecting rod, 30—roller, 31—protective sleeve, 32—sheath, 33—sleeve cylinder, 34—guide block, 35—limiting pin, 36—braking ring, 37—second connecting rod, 38—second locking block, 39—third connecting rod, 40—seventh spring, 100—subject, 101—limited shrinking structure, and 102—axial braking structure.

#The depth limiting device used for a drill of the present invention is further described in detail by combining with the accompanying drawings.

#The depth limiting device used for a drill includes a main body; an axial braking structure, braking the drill rod axially at any time; and a limited shrinking structure capable of sliding relative to a drill rod of the drill, realizing limited extension of the drill rod. The axial braking structure is attached to the main body.