JPH0324172Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a chuck for detachably attaching a cutting tool to a rotating shaft, and this chuck is mainly attached to the rotating shaft of a dental treatment instrument.

(Prior Art) Conventionally, a stopper of a chuck is closed by the tension of a coil spring attached to a rotating shaft together with the stopper.

(Problem that the invention aims to solve) Therefore, if the diameter of the wire of the coil spring is increased in order to strengthen the stopping force of the stopper, it is possible to There was a problem where the chuck could not be accommodated.

In addition, since the weight balance of coil springs is uneven, problems such as uneven rotation of the rotating shaft and abnormal wear of the bearings occur in contra heads where the rotating shaft rotates at high speed.

The present invention was devised in view of these problems and aims to provide a chuck that can provide a stopping force without using a coil spring and that can be opened and closed easily and quickly.

(Means for Solving the Problems) The present invention has a cutter stop that has an inner diameter smaller than the outer diameter of the cutter and has a plurality of slots cut in the direction of the center line at one opening end. , a cylindrical stopper with a cutter insertion part whose outer diameter is slightly larger than the inner diameter of the cutter insertion end of the rotating shaft at the other open end, and a center line so that the free end side becomes thinner. A cylindrical opening/closing body with a plurality of wedges protruding from one opening end, each side of which is provided with an inclined surface inclined with respect to the direction, and a cutter insertion portion of the stop body inserted from one opening end. By press-fitting and fixing into one open end, the cutter stop part of the stop body can be moved in the radial direction, and the opening/closing body inserted from the other open end can be held movably in the center line direction. It consists of a cylindrical rotating shaft.

(Function) When the opening/closing body is pressed and the wedge part of the opening/closing body is pressed into the slot against the restoring force of the stop body, the cutter stop part of the stop body is pushed open in the radial direction and the cutter cannot be inserted or removed. ,
When the opening/closing body is released, the cutting tool stopping portion of the stopping body pushes out the wedge portion of the opening/closing body from the slot due to the restoring force of the stopping body, and comes into pressure contact with the outer circumferential wall surface of the cutting tool, thereby stopping the cutting tool.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

The figure shows the configuration of a dental contrahead equipped with an embodiment of the present invention. 1 shows a cutting tool insertion end 1a formed with a smaller inner diameter at one open end, and a thread cut on the inner periphery. The rotating shaft 1 is a substantially cylindrical shaft having a cylindrical opening/closing body operation end 1b provided at the other open end, and is rotatably attached to a head case 2 via a bearing 3. 4 is a gear protruding in the radial direction on the outer circumferential wall surface of the intermediate portion of the rotating shaft 1; 5 is a gear whose inner diameter is slightly smaller than the outer diameter of the cutting tool 16 (indicated by a dotted line); The cutter insertion part has a cutter stop part 5a in which a slot 6 is cut in the center line direction at one open end, and the outer diameter is formed one step larger than the inner diameter of the cutter insertion end part 1a. 5b is provided at the other open end, each having a substantially cylindrical shape,
When this stopper 5 is inserted into the rotary shaft 1 and the cutter insertion part 5b is press-fitted and fixed to the cutter insertion end 1a, the stopper 5 is formed between the inner circumferential wall surface of the rotary shaft 1 and the outer circumferential wall surface of the cutter stopper part 5a. A gap is formed in the cutter stop portion 5a.
is mounted in the rotating shaft 1 in a radially displaceable manner. Reference numeral 7 denotes a cylindrical opening/closing device having a plurality of V-shaped wedge portions 7b protruding from one opening end and having inclined surfaces 7a inclined with respect to the center line direction on both sides so that the free end side becomes narrower. With the body, this opening/closing body 7
is held on the side of the opening/closing body operating end 1b of the rotating shaft 1 so as to be movable in the direction of the center line. Reference numeral 8 denotes a retaining ring screwed onto the inside of the opening/closing body operating end 1b of the rotating shaft 1;
By adjusting the screwing amount to
This prevents the wedge part 7b of the opening/closing body 7 moving inside the slot from coming out of the slot 6. 9 is a head cover that covers the operating end 2a of the opening/closing body on the side where the rotating shaft 1 and bearing 3 are inserted into the head case 2; 10 is a mounting ring that holds the head cover 9 movably in the direction of the center line of the rotating shaft 1; This attachment ring 10 is screwed onto the inside of the opening/closing body operating end 2a of the head case 2. Reference numeral 11 denotes a retaining ring for fixing the rotary shaft 1 at a predetermined position in the head case 2, and the retaining ring 11 is screwed inside the mounting ring 10.
Reference numeral 12 denotes a coil spring interposed between the head cover 9 and the retaining ring 11, and the coil spring 12 biases the head cover 9 away from the opening/closing body 7, that is, upward in the figure, by its tension. 13
14 is a power transmission shaft disposed so that its center line is orthogonal to the center line of the rotating shaft 1; A bearing 15 is a gear fixed to the tip of the power transmission shaft 13. This gear 15 meshes with the gear 4, and when the power transmission shaft 13 is driven, the rotating shaft 1 rotates.

In this embodiment configured as described above, the head cover 9 is pushed into the head case 2 with the user's fingers against the tension force of the coil spring 12, and the head cover 9 is brought into contact with the opening/closing body 7. When the head cover 9 is further pushed into the head case 2 together with the opening/closing body 7 and the wedge portion 7b is press-fitted into the slot 6, the cutter stop portion 5a of the stop body 5 is displaced in the radial direction by the inclined surface 7a. The so-called chuck is opened, and the cutter 16 can be inserted and removed.

Also, remove the user's fingers from the head cover 9,
When the force applied to the head cover 9 is removed, the head cover 9 is pushed upward in the figure by the tension of the coil spring 12 and returns to its original position, and the cutter stopper 5a of the stopper 5 returns to its original position. The force pushes the opening/closing body 7 upward in the figure and brings it into pressure contact with the outer peripheral wall surface of the cutting tool 16, so that the so-called chuck is closed, and the cutting tool 16 is stopped by the stopper 5 as shown by the dotted line in the drawing. .

(Effects of the invention) As explained above, according to the invention, the restoring force of the stop body can be used as is as the force for stopping the cutting tool, so the stopping force can be strengthened without increasing the diameter of the rotating shaft, and Since it is easy to design the weight balance of the stopper body and the opening/closing body, uneven rotation of the rotary shaft and abnormal wear of the bearings hardly occur in contraheads where the rotary shaft rotates at high speed. This has the effect of eliminating the drawbacks of

In addition, the restoring force in the direction of the center of the stopper body can be used directly as a force for stopping the cutter, so when the wedge part of the opening/closing body is press-fitted into the slot of the stopper body, the cutter retaining part of the stopper body opens and the opening/closing body When released, the cutter stop part of the stop body closes while pushing out the wedge part of the opening/closing body from the slot, producing the effect that the cutter can be attached and detached easily, quickly and reliably. This is very important from the viewpoint of improving the operability of dental treatment instruments, etc., where cutting tools of different diameters are frequently replaced for treatment.

[Brief explanation of drawings]

The figure is a central vertical cross-sectional view of a dental contra head equipped with an embodiment of the present invention. 1... Rotating shaft, 1a... Cutting tool insertion end, 1b...
... Opening/closing body operating end, 2... Head case, 2a...
... Opening/closing body operation end, 5... Stop body, 5a... Cutting tool stopping part, 5b... Cutting tool insertion part, 6... Slot, 7...
... Opening/closing body, 7a... Inclined surface, 7b... Wedge portion.

Claims (1)

[Scope of Claim for Utility Model Registration] A chuck for removably attaching a cutting tool to a rotary shaft rotatably housed in a head case, the inner diameter of which is smaller than the outer diameter of the cutting tool, and a plurality of slotted holes located at the center of the chuck. A cutting tool stop portion cut in the linear direction is provided at one opening end, and a cutting tool insertion portion whose outer diameter is slightly larger than the inner diameter of the cutting tool insertion end of the rotating shaft is provided at the other opening end. A cylindrical opening/closing body having a cylindrical stop body and a plurality of wedge parts protruding from one open end, each of which has a plurality of wedge parts on both sides having sloped surfaces that are inclined with respect to the center line direction so that the free end side becomes thinner. and, by press-fitting and fixing the cutter insertion portion of the stopper inserted from one open end into the one open end, the cutter stopper of the stopper is internally movable in the radial direction, and , and the cylindrical rotating shaft that holds the opening/closing body inserted from the other opening end so as to be movable in the center line direction; When pressed into the slot against the restoring force,
When the cutter stop part of the stop body is pushed open in the radial direction to allow the cutter to be inserted and removed and the opening/closing body is released, the cutter stop part of the stop body is pushed open by the restoring force of the stop body to allow the cutter to be inserted and removed. The chuck is characterized in that the wedge part is pushed out of the slot and pressed against the outer peripheral wall surface of the cutting tool to stop the cutting tool.