JPH0591645U - Cast cutter - Google Patents

Abstract

(57) [Abstract] [Purpose] No friction is generated in the transmission mechanism that converts the motor rotation motion into the swing motion of the blade, and there is no wear.
It has been improved so that a smoother blade swing motion can be performed. [Structure] The main shaft 3 of the eccentric bearing 1 fixed to a predetermined eccentric position of the inner ring 2 is connected to the motor output shaft 5, and a plurality of outer rings 4a, 4b ... The oscillator 6 is attached to each outer ring 4 of the eccentric bearing 1.
a, 4b, and zigzag-shaped guide pieces 7a, 7b ... Which are in contact with one side of each outer ring 4a, 4b.
The eccentric bearing 1 is eccentrically rotated by the rotation of the motor output shaft 5 to follow the guide pieces 7a, 7b ... Of the oscillator 6,
The oscillator 6 is swung about a swing shaft 8 to move the blade 9
Rock.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a cast cutter suitable for cutting a cylindrically shaped body such as a cast along its outer circumference.

[0002]

[Prior Art]

 Conventionally, in order to remove a cast used for treatment of a bone fracture or the like, the cast is removed by cutting the outer periphery of the cast with the cast attached to the body. In such a cutter, it is dangerous if the blade cuts along the outer periphery of the cast when it reaches the body part.Therefore, by swinging the blade, the blade touches the body surface. Also, the elasticity of the skin prevents cuts.

That is, as shown in FIG. 5 (a), the conventional cutter of this type has one eccentric bearing 5 between the front and rear support bearings 51, 51 pivotally mounted in a main body case (not shown). Two main shafts 53 are pivotally attached. The eccentric bearing 52 is configured such that the inner ring 52a is slidably rotated on the inner periphery of the outer ring 52b and the main shaft 53 is fixed to the eccentric position of the inner ring 52a. The main shaft 53 is rotatably supported by the support bearings 51, 51. The main shaft 53 is connected to an output shaft 53a of a motor (not shown).

With such a configuration, when the motor is driven to rotate the output shaft 53a, the outer ring 52b rotates eccentrically around the main shaft 53. The eccentric bearing 52 is sandwiched between the horseshoe-shaped guide pieces 55, 55 of the oscillator 54 (state shown in FIG. 5 (b)), and a supporting bearing 59 is interposed between a shaft fitting portion 56 having a rectangular cross section provided on the upper portion of the oscillator 54. When the rectangular shaft portion 57a of the swing shaft 57 rotatably supported by the main body case is fitted and the circular blade 59 is attached to the end face 58a of the holder 58 fixed to the tip of the swing shaft 57, The outer ring 52b of the eccentric bearing 52 is eccentrically rotated by the drive of the rotor, and the outer ring 52b is driven by the guide pieces 55, 55 of the oscillator 54 to swing the oscillator 54, whereby the blade 59 swings.

[0005]

[Problems to be solved by the device]

 However, in the above cutter, the oscillator 54 driven by the eccentric bearing 52 is configured such that the horseshoe-shaped guide pieces 55, 55 sandwich both sides of the outer ring 52b of one eccentric bearing 52 at the same time (FIG. 5). (See (c)) When the outer ring 52b eccentrically rotates in the guide pieces 55, 55 as described above, one side of the outer ring 52b rolls against the wall surface of one guide piece 55, but one side of the outer ring 52b. Will slide on the wall surface of one guide piece 55, and the frictional force of the sliding surface on one side will also cause a sliding phenomenon on the rolling surface on one side, and as a result, both sides of the outer ring 52b and the guide piece. There was a problem that both wall surfaces of 55 and 55 slide and generate friction, which causes wear of the sliding surface, heat generation, and noise.

The present invention has been made in view of the above circumstances, in which friction is not generated in the transmission mechanism unit that converts the motor rotational movement into the swinging movement of the blade, and the blade is smooth and has no wear. It is an object of the present invention to provide a cast cutter improved so as to be able to perform the swinging motion of the.

[0007]

[Means for Solving the Problems]

 In order to solve the above problems, the cast cutter of the present invention coaxially connects the main shaft 3 of an eccentric bearing 1 having a main shaft 3 fixed at a predetermined eccentric position of an inner ring 2 to a motor output shaft 5. At the same time, the outer ring 4 of the eccentric bearing 1 is sandwiched between the guide pieces 7 of the oscillator 6, and a circular blade 9 is attached to the top of the oscillator 6 at the tip of a swing shaft 8 fixed in parallel with the main shaft 3 of the eccentric bearing 1. In the cast cutter, the eccentric bearing 1 is formed by connecting a plurality of outer rings 4a, 4b ... In the axial direction, and the oscillator 6 contacts each outer ring 4a, 4b ... of the eccentric bearing 1 on one side. Are formed into staggered guide pieces 7a, 7b, ... By the rotation of the motor output shaft 5, the outer rings 4a, 4b, ... Of the eccentric bearing 1 are guided by the respective guides of the oscillator 6. Are driven by 7a, 7b, ... To oscillate the oscillator 6 about the oscillating shaft 8 so that the blade 9 oscillates. The eccentric bearing 1 has three outer rings. 4a, 4b, 4c are connected to each other, and the oscillator 6 has three zigzag guide pieces 7a, 7b, 7c which are in contact with the outer rings 4a, 4b, 4c of the eccentric bearing 1 one by one. It may be configured.

[0008]

[Action]

 The operation of the present invention will be described with reference to FIGS. 4 (a), 4 (b) and 4 (c). The oscillator 6 driven by the eccentric bearing 1 contacts the outer rings 4a, 4b, 4c of the eccentric bearing 1 one by one. Since the staggered guide pieces 7a, 7b, 7c are formed, the outer rings 4a, 4b, 4c of the eccentric bearing 1 are eccentrically rotated within the proposed pieces 7a, 7b, 7c of the oscillator 6 by the rotation of the motor output shaft 5. In doing so, the outer rings 4a, 4b, 4c roll while being in contact with the respective guide pieces 7a, 7b, 7c one by one.

That is, since the conventional oscillator 54 shown in FIG. 5 is in contact with the outer ring 52 by sandwiching the outer ring 52 from both sides at the same time, the outer ring 52 rolls on the wall surface of one guide piece 55 and slides on one wall surface. However, in the present invention, only one side of each outer ring 4a, 4b, 4c is in contact with each guide piece 7a, 7b, 7c and the other side is open, so that the eccentric bearing is formed. Due to the eccentric rotation of 1, only the contact surfaces of the outer rings 4a, 4b, 4c and the guide pieces 7a, 7b, 7c roll, and there is no need to form a sliding surface for one outer ring as in the conventional case. Moreover, since the plurality of (three in the embodiment) guide pieces 7a, 7b, 7c are arranged in a staggered manner, the outer rings 4a, 4b, 4c can be held as a whole.

[0010]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an internal open view of the cast cutter of the present invention. FIG. 2 is an external view of the cast cutter shown in FIG. 3 (a) is a perspective view of a main part of a blade mounting portion of the cast cutter of FIG. 1, and FIG. 3 (b) is a side view of FIG. 3 (a). FIG. 4 (a) is an exploded perspective view of a main part of a mechanism for converting the motor rotation motion of the cast cutter shown in FIG. 1 into a swing motion, and FIG. 4 (b) is a side view of FIG. 4 (a). FIG. 4 (c) is a schematic view showing the connection structure of the eccentric bearing and the oscillator.

Front and rear support bearings 12a and 12b are pivoted on main body support portions 11a and 11b formed in the main body case 10, respectively, and a main shaft 3 of the eccentric bearing 1 is pivotally mounted between the support bearings 12a and 12b. To do. The eccentric bearing 1 fixes the main shaft 3 to the eccentric position of the inner ring 2, and also arranges the outer rings 4a, 4b, 4c on the outer periphery of the inner ring 2 along the axial direction of the main shaft 3 so as to be independently slidably rotatable. There is. Balancers 20a and 20b are fixed to the main shaft 3 near both ends of the eccentric bearing 1 at positions that alleviate the eccentricity, and both ends of the main shaft 3 are rotatably supported by the support bearings 12a and 12b as described above. It is supported by the body support portions 11a and 11b. Then, one end of the main shaft 3 is connected to the output shaft 5 of the DC motor 13 housed in the main body case 10, and the other end is fixed by being fastened with a nut 3a at the outer end of the main body supporting portion 11a. With such a configuration, when the motor 13 is driven, the main shaft 3 rotates via the motor output shaft 5, and the eccentric bearing 1 rotates eccentrically around the main shaft 3.

On the other hand, an oscillator 6 is arranged above the eccentric bearing 1. The oscillator 6 is formed with three staggered guide pieces 7a, 7b, 7c which are in contact with the outer rings 4a, 4b, 4c of the eccentric bearing 1 one by one. Then, the rectangular shaft portion 18 of the swing shaft 8 is fitted to the shaft fitting portion 16 of the rectangular cross section provided at the end portion of the oscillator 6, and the nut 21 is fastened to the bolt screw 8a of the swing shaft 8. Thus, the oscillator 6 is fixed to the swing shaft 8.

After the guide pieces 7 a, 7 b, 7 c of the oscillator 6 are fitted to the outer rings 4 a, 4 b, 4 c of the eccentric bearing 1, the support bears pivotally attached to the front and rear ends of the swing shaft 8. The rings 19a and 19b are pivotally mounted on the main body support portions 17a and 17b of the main body case 10, and the bolt screw 8b at the rearmost end of the swing shaft 8 is fastened by a nut 22 at the outer end of the main body support portion 17b.

In this structure, the eccentric bearing 1 is held from the left and right by the sandwiching structure formed by the guide pieces 7a, 7b, 7c as a whole, and the outer races 4a, 4b, Only one side of 4b, 4c is in contact with the other side, and the other side is open. Due to the eccentric rotation of the eccentric bearing 1, the outer rings 4a, 4b, 4c can roll on the guide pieces 7a, 7b, 7c only on the contact surface. it can.

A holder 23 is fixed to the tip end of the swing shaft 8, and two protrusions 24, 24 are provided on both ends of the holder 23 so as to project. As shown in FIG. 3, the protrusions 24, 24 are fitted into two facing portions of the four recesses 9b, 9b ... Formed at both ends of the inner hole 9a provided at the center of the circular blade 9. After the blade 9 is fitted to the front surface 23a of the holder 23, the recesses 25b and 25b formed on the mating surface of the cap 25 are inserted into the screw holes 23b provided at the center of the front surface of the holder 23. The projections 24, 24 of the holder 23 are fitted to the holder 23, and a screw 26 with a square hole that locks to the outer end of the center hole 25a of the cap 25 is tightened and fixed.

In FIG. 1, 30 is a cooling fan for the motor 13, 31 is a motor rotation control circuit, and 32 is a power cord holder.

With the above configuration, when the main shaft 3 of the eccentric bearing 1 rotates as the motor output shaft 5 rotates by driving the motor 13, the outer rings 4a, 4b, 4c rotate eccentrically, and the oscillator 6 Driven by the guide pieces 7a, 7b, 7c of FIG. 1 to reciprocally rotate the oscillator 6 at a constant center angle in accordance with the eccentricity of the eccentric bearing 1 described above, whereby the blade 9 is swung to form a cylinder such as a cast. The shaped feature G (see FIG. 2) can be cut along its circumference.

[0019]

[Effect of the device]

 According to the cast cutter of the present invention described above, when the blade 9 is operated, the outer rings 4a, 4b, 4c of the eccentric bearing 1 slide on the contact surfaces of the guide pieces 7a, 7b, 7c of the oscillator 6. Therefore, the blade 9 smoothly rolls without causing wear on the contact surface between the eccentric bearing 1 and the oscillator 6 as in the case of the conventional cutter, suppressing noise and heat generation. be able to.

The present invention enables stable and safe cutting of a cylindrical forming body such as a cast by the stable swing motion of the blade as described above, and is particularly suitable for medical use. We can provide extremely reliable cutters.

[Brief description of drawings]

FIG. 1 is an internal open view of a cast cutter according to the present invention.

FIG. 2 is an external view of the cast cutter shown in FIG.

3 (a) is a perspective view of an essential part of a blade mounting portion of the cast cutter of FIG. 1, and FIG. 3 (b) is a side view of FIG. 3 (a).

4 (a) is an exploded perspective view of a main part of a mechanism for converting a motor rotation motion of the cast cutter shown in FIG. 1 into a swing motion, and FIG. 3 (b) is a side view of FIG. 3 (a). It is a figure and Drawing 3 (c) is a schematic diagram showing the connection composition of an eccentric bearing and an oscillator.

5 (a) is an exploded perspective view of a main part of a mechanism for converting a motor rotary motion of a conventional cast cutter into a swing motion, and FIG. 5 (b) is a side view of FIG. 5 (a). Yes, FIG. 5 (c) is a schematic view showing the connection configuration of the eccentric bearing and the oscillator.

[Explanation of sign]

1 ... Eccentric bearing, 2 ... Inner ring, 3 ... Main shaft, 4a, 4
b, 4c ... Outer ring, 5 ... Motor output shaft, 6 ... Oscillator,
7a, 7b, 7c ... Guide piece, 8 ... Swing shaft, 9 ... Circular blade.

Claims (2)

[Scope of utility model registration request] 1. A main shaft 3 fixed to a predetermined eccentric position of an inner ring 2.
The main shaft 3 of the eccentric bearing 1 having the above is coaxially connected to the motor output shaft 5, the outer ring 4 of the eccentric bearing 1 is sandwiched by the guide piece 7 of the oscillator 6, and the eccentric bearing 1 is provided above the oscillator 6. In a cast cutter in which a circular blade 9 is attached to the tip of a swing shaft 8 fixed in parallel with the main shaft 3, the eccentric bearing 1 is formed by connecting a plurality of outer rings 4a, 4b ... Reference numeral 6 denotes each outer ring 4a, 4 of the eccentric bearing 1.
b-staggered guide pieces 7a that come into contact with b ...
Are formed to rotate the motor output shaft 5 so that the outer rings 4a, 4b of the eccentric bearing 1 follow the guide pieces 7a, 7b of the oscillator 6 to swing the oscillator 6. A cast cutter characterized by swinging about a shaft 8 so that the blade 9 swings. 2. The eccentric bearing 1 includes three outer rings 4a,
4b and 4c are connected to each other, and the oscillator 6 is in contact with the outer rings 4a, 4b and 4c of the eccentric bearing 1 on one side and three zigzag guide pieces 7a, 7b and 7c.
The cast cutter according to claim 1, wherein the cast cutter is formed.