JP2000024008A - Centrifugal casting machine for dentist - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable horizontal balance adjusting work for a centrifugal casting machine for dentist to be precisely and simply executed by making the structure so that the horizontal balancing of a rotary arm is enabled by pushing out a pair of balance pins equipped symmetrically with respect to the rotation center on the upper face of a motor boss and connecting and fixing of the rotary arm are made by drawing back the balance pins. SOLUTION: Two balance pin holes 12 are formed on symmetrical positions with respect to the rotation center on the upper face of a motor boss 14 attached on the upper end of the rotation drive shaft 15 of a drive motor 16. Springs 8 and balance pins 8 are housed in the holes 12 so that the balance pins are protruded by loosening a rotation arm fixing screw 7. Thus the whole weight of the rotation arm including a crucible containing a mold 1 and a casting material is supported by the balance pins 10 which are to be support points for horizontal balance adjustment. When the rotation arm fixing screw 7 is fastened, the balance pins 10 are housed in the holes 2 to connect and fix on the rotation drive shaft 15. Thus horizontal balance adjusting is made easier.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a dental member such as a crown restoration or a defective prosthesis by using a centrifugal force to cast a metal material or a ceramic material for dental casting into a mold. It relates to a dental centrifugal casting machine.

[0002]

2. Description of the Related Art In a dental centrifugal casting machine in which a rotating arm provided with a mold holding unit, a crucible holding unit and a balance weight rotates horizontally, a stable rotation can be obtained without vibration of the rotating arm, and safety is ensured. In addition, in order to prevent an excessive force from being applied to the rotary drive shaft, it is necessary to adjust the horizontal balance of the rotary arm by changing the position of the balance weight according to the weight of the mold and the casting material. For this reason, in the conventional horizontal rotary dental casting machine, for example, a steel round bar is inserted and fixed at a right angle to the rotary drive shaft, and the steel is positioned at a position facing the steel round bar on the lower surface of the center block of the rotary arm. Carve a groove with a width slightly larger than the diameter of the round bar made of steel and a depth slightly smaller than the diameter of the round bar made of steel, and put the rotating arm so that the groove fits with the round bar made of steel. After adjusting the position of the balance weight so that the rotating arm is horizontal with the fulcrum as a fulcrum, a mechanism is provided such that the rotating arm fixing screw is tightened to connect and fix the rotating drive shaft and the rotating arm. The fitting of the steel round bar and the groove carved in the rotating arm in this mechanism not only determines the fulcrum of the rotating arm as described above, but also loosens the rotating arm fixing screw at the time of starting rotation, etc. It also has the function of preventing the rotating arm and the rotating drive shaft from slipping inside.

[0003]

It is said that the quality of the result of centrifugal casting is mostly determined very early in the rotation start. That is, in order to obtain a good centrifugal casting without casting defects, to reach a predetermined number of rotations in a short time as possible,
Stable rotation without vibration is required. For that purpose, precise adjustment of the horizontal balance of the rotary arm and strong connection and fixing between the rotary arm and the rotary drive shaft are essential.

In particular, if the horizontal balance of the rotary arm is not precisely adjusted, not only the centrifugal force decreases, but also the vibration during rotation increases, and the centrifugal force does not work properly on the molten casting material. In addition, casting defects such as insufficient casting of the details of the mold and incorporation of air bubbles into the casting are likely to occur. If the horizontal balance of the rotating arm is not precisely adjusted, excessive force is applied to the rotating drive shaft and its bearing during rotation, and the rotating arm is likely to cause a seesaw motion in which the rotating arm vibrates up and down. Not only does the loosening of the fixing screw loosen the connection between the rotating arm and the rotating drive shaft, but also forces may act in undesirable directions, possibly causing molds and crucibles to come off their holding parts and fly. There is also a possibility that it will be in a state. Therefore, in the horizontal rotary dental centrifugal casting machine, it is necessary to precisely adjust the horizontal balance of the rotary arm, and to perform the casting operation by firmly connecting and fixing the rotary arm to the rotary drive shaft.

[0005] In the conventional dental centrifugal casting machine as described above, the smaller the contact area between the steel round bar and the groove facing the steel round bar, the more accurately the horizontal balance of the rotating arm can be obtained. On the other hand, since the rotation arm and the rotation drive shaft are connected and fixed at the contact portion between the steel round bar and the groove facing the steel rod, from the viewpoint of preventing the rotation arm and the rotation drive shaft from slipping, The larger the contact area between the round bar and the groove facing the round bar, the better. That is, with such a mechanism, it is difficult to satisfy both accurate horizontal balance of the rotary arm and strong connection and fixation between the rotary arm and the rotary drive shaft.

[0006] The material of the center block of the rotary arm for carving a groove facing the steel round bar is usually a metal material,
In particular, in order to reduce the weight of the rotating arm and shorten the time required to reach a predetermined number of revolutions at the time of startup, a low-density metal such as aluminum is often used. When the rotating arm fixing screw is strongly tightened to firmly connect with the steel round bar, the bottom of the groove that contacts the steel round bar is plastically deformed along the shape of the steel round bar and faces the steel round bar As a result of the further increase in the contact area with the groove, there arises a problem that it is difficult to accurately adjust the horizontal balance of the rotating arm.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and provides a mold and a casting mold for a dental centrifugal casting machine in which a rotating arm having a mold holding portion, a crucible holding portion, and a balance weight rotates horizontally. After adjusting the horizontal balance of the entire rotating arm including the mold and the crucible containing the casting material after setting the crucible containing the material for rotation on the rotating arm, the adjustment can be performed accurately and easily and the rotating arm It is an object of the present invention to provide a centrifugal dental casting machine having a mechanism in which a rotation arm and a rotation drive shaft are firmly connected and fixed by tightening a fixing screw.

[0008]

In order to solve the two problems simultaneously, the present inventors need to accurately and simply adjust the horizontal balance of the rotary arm and firmly connect and fix the rotary arm and the rotary drive shaft. It has been conceived that it is preferable to separate the mechanism forming the fulcrum when the horizontal balance of the rotary arm is taken from the connection and fixing mechanism of the rotary arm and the rotary drive shaft, and as a result of intensive studies, completed the present invention. Things.

That is, the present invention provides a dental centrifugal casting machine in which a rotating arm provided with a mold holding part, a crucible holding part and a balance weight rotates horizontally, and rotates a crucible containing a mold to be cast and a casting material. After setting on the arm, loosen the rotating arm fixing screw, the two balance pins provided on the upper surface of the motor boss attached to the upper end of the rotary drive shaft at the symmetrical position with the rotation center as the center Extruded from the balance pin storage hole, it supports the weight of the entire rotating arm including the crucible containing the mold and casting material, and the tip of the balance pin serves as a fulcrum. Adjustment is possible, and the rotating arm fixing screw is tightened again, so that the rotating arm facing the balance pin can be adjusted. A dental arm having a mechanism in which the rotating arm is firmly connected to and fixed to the rotary drive shaft while being pushed back by the lower surface of the center block into the balance pin housing hole and maintaining the adjusted horizontal balance. It is a centrifugal casting machine.

That is, in the present invention, two balance pin storage holes are provided at the symmetrical position about the center of rotation on the upper surface of the motor boss firmly attached to the upper end of the rotary drive shaft. When the rotation arm fixing screw is loosened, the tip of the balance pin protrudes from the balance pin storage hole by a spring to support the weight of the entire rotation arm including the crucible containing the mold and casting material. , And serve as a fulcrum when adjusting the horizontal balance of the rotating arm.

After adjusting the horizontal balance of the rotary arm, the rotary arm is tightened by tightening the rotary arm fixing screw, whereby the rotary arm is connected and fixed to the rotary drive shaft while maintaining the adjusted horizontal balance. At this time, the balance pin is accommodated in the balance pin storage hole, and the upper surface of the motor boss and the lower surface of the center block of the rotary arm are fixed by surface contact, so that the connection and fixation of the rotary arm and the rotary drive shaft are further strengthened.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings.
FIG. 1 is a side view of a rotary arm portion (with a rotary arm fixing screw loosened) of a centrifugal dental casting machine according to the present invention. In the dental centrifugal casting machine according to the present invention, two balance pin receiving holes 12 are provided at symmetric positions about the rotation center on the upper surface of a motor boss 14 firmly attached to the upper end of a rotary drive shaft 15 of a drive motor 16. The spring 11 and the balance pin 10 are placed in the balance pin storage holes, respectively. When the rotary arm fixing screw 7 is loosened as shown in FIG. 1, the spring protrudes the tip of the balance pin from the balance pin storage hole. Thus, while supporting the weight of the entire rotating arm including the mold 1 and the crucible 4 containing the casting material, the rotating arm serves as a fulcrum when the horizontal balance of the rotating arm is adjusted.

The balance pin comes into contact with the lower surface of the center block 8 of the opposing rotary arm. From the viewpoint of the accuracy of the horizontal balance adjustment of the rotary arm,
The smaller the contact area, the better. Therefore, the tip portion of the balance pin has a conical shape, a hemispherical shape, a truncated conical shape having a small upper surface area, or the like.

The lower portion of the balance pin has a columnar shape. The balance pin storage hole is cylindrical to guide the balance pin, the diameter of which is slightly larger than the diameter of the balance pin and spring, the depth of which accommodates the spring and balance pin, and the rotating arm at the tip of the balance pin. The depth should be such that the tip of the balance pin slightly protrudes from the hole even when supporting the entire weight. The shape of two balance pin storage holes,
The dimensions are the same.

The materials of the balance pin and the spring are not particularly limited, but usually made of steel. Two springs support the weight of the rotating arm as a whole, and when the rotating arm fixing screw is tightened, as shown in Fig. 2, a spring with an appropriate strength is installed so that the balance pin can easily fit into the balance pin storage hole. Used.

The lower arm of the center block of the rotary arm and the upper surface of the motor boss are connected and fixed by attaching the rotary arm to the motor boss fixed to the upper end of the rotary drive shaft and tightening the rotary arm fixing screw. However, if the large torque applied to the rotating arm at the start and stop of rotation is excessive, and there is a possibility that the sliding between the surfaces will loosen the tightening of the rotating arm fixing screw, a balance pin should be attached to the upper surface of the motor boss. The two anti-sliding pins 13 are mounted at different positions, preferably on a line orthogonal to the line connecting the two balance pins, and symmetrically about the center of rotation, and the center block of the center block of the rotating arm opposed thereto is mounted. The lower surface is provided with a hole into which the anti-sliding pin fits, and when the rotating arm fixing screw is tightened, the hole and the anti-sliding pin fit into It is preferable that the mechanism for preventing the sliding between the center block lower surface and a motor boss top surface.

[0017]

According to the dental centrifugal casting machine of the present invention, the horizontal balance of the entire rotating arm including the mold and the crucible containing the casting material can be accurately and easily adjusted.
Since the rotary arm and the rotary drive shaft can be firmly connected and fixed, casting can be performed safely, and a defect-free casting can be stably obtained.

[Brief description of the drawings]

FIG. 1 is a side view of a rotary arm portion (with a rotary arm fixing screw loosened) of a dental centrifugal casting machine according to the present invention.

FIG. 2 is a side view of a rotating arm portion (with a rotating arm fixing screw tightened) of the centrifugal dental casting machine according to the present invention.

FIG. 3 is a plan view of a rotating arm part of the centrifugal dental casting machine according to the present invention.

[Description of Signs] 1 Mold 2 Mold holder 3 Back plate 4 Crucible 5 Crucible stopper 6 Crucible holder 7 Rotating arm fixing screw 8 Rotating arm center block 9 Balance weight 10 Balance pin 11 Spring 12 Balance pin storage hole 13 Slip prevention pin 14 Motor boss 15 Rotary drive shaft 16 Drive motor

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Seiji Kihara 3230 Honami, Bizen City, Okayama Prefecture (72) Inventor Toshimasa 1-17-17, Jotodai Higashi, Okayama City (72) Inventor Makoto Mitsudo Akaiwa, Okayama Prefecture 200F term of 6-6-6 Sakuragaoka east, Kumayama-machi, Gunma 4C059 HH02 HH04 HH25 HH53 HH54

Claims (1)

[Claims] 1. A dental centrifugal casting machine in which a rotary arm provided with a mold holder, a crucible holder and a balance weight rotates horizontally, a crucible containing a mold to be cast and a casting material is set on the rotary arm. After that, by loosening the rotating arm fixing screw, two balance pins provided at symmetrical positions around the rotation center on the upper surface of the motor boss attached to the upper end of the rotating drive shaft are stored by the spring. Extruded from the hole, supports the weight of the entire rotating arm including the crucible containing the mold and casting material, and the balance pin tip serves as a fulcrum, allowing accurate adjustment of the horizontal balance of the entire rotating arm by the balance weight And re-tighten the rotation arm fixing screw, so that the balance pin faces the center arm of the rotation arm facing the balance pin. Tsu is pushed back by the click underside fit into balance rail pin receiving hole, while maintaining the horizontal balance is adjusted, rigidly coupled to the rotating arm is a rotary drive shaft,
A dental centrifugal casting machine comprising a fixed mechanism.