DE3236061A1 - Centrifugal caster, in particular for dental uses - Google Patents

Abstract

The invention relates to a centrifugal caster, in particular for dental uses, and to an automatic centrifugal casting machine, equipped therewith, which has a device for compensating the unbalance in the case of different sizes of casting muffle, the device comprising a centrifuging arm secured at the end of a drive shaft, an essentially vertically arranged muffle holder at one end of the centrifuging arm, a balance weight arranged displaceably along the other end of the centrifuging arm, and a melting crucible. The centrifugal caster according to the invention has the advantage that unbalances during the centrifuging operation can be largely avoided and, furthermore, the automatic centrifugal casting machine has the advantage that access to the rotating centrifuging arm is prevented. The centrifugal caster is distinguished by the fact that the muffle holder and the balance weight are in mutual drive connection in such a way that, as the muffle holder is set to the size of the attached casting muffle, the balance weight is displaced synchronously to the corresponding position on the centrifuging arm to balance the weight of the muffle.

Description

description

Cast iron extractor, especially for dental applications. The object The present invention relates to a cast centrifuge, in particular for dental applications, as well as an automatic casting centrifugal machine according to the preambles of the claims 1 and 6.

Cast centrifugal machines of this type are known. You can find for example Use in dental laboratories for the production of dentures such as prostheses and cast parts made of precious metals or substitute materials. One on a sling arm such a machine is on the one hand a height-adjustable muffle carrier for the Receipt of casting muffles of different sizes and, on the other hand, a leveling compound, which according to the respective muffle mass at the appropriate point on the throwing arm is locked, a crucible or a melting trough is also provided.

Both the muffle carrier and the leveling compound have to be depending on Size of the muffle can be brought into the correct position to avoid an imbalance when Switch off the spin process if possible.

In such known devices, the sling arm is in a horizontal position Position on a vertical axis of a drive element, e.g. a spiral spring or a motor, fixed and possibly brought into a housing.

This known slingshot no longer meets today's requirements in terms of accident prevention and ease of use.

The pulling up (tensioning) of the drive spring of the sling arm, the Handling the sling arm when the spring is tensioned and the sling is in operation dangerous. Furthermore, it is often used by the operating personnel, especially in the case of motor-driven If the leveling compound is not adapted to the size of the muffle used, whereby at the high circumferential speed of the sling arm as a result of arising Imbalance the whole machine is subject to heavy mechanical loads and is very good would have to be attached in order to avoid incorrect casting due to vibrations.

The object of the present invention is now to provide a cast centrifuge to create, which avoids the disadvantages of the known.

It is further the object of the invention to provide a machine, which enables safe working and good accessibility as well as a has easy handling. According to the invention, the tasks according to the characterizing features of claims 1 and 6 solved. Further advantageous training of the invention are defined in the subclaims.

The drive connection between the height adjustment of the muffle holder to adapt to the size of the muffle with the leveling compound on the opposite one Armende includes errors that lead to damage to drive parts and a require rigid attachment of the machine.

Due to the inclined arrangement of the sling arm in the preferred Embodiment, there is no need for further costly precautions to reduce the imbalance.

Another advantage to reduce the imbalance is through the stepless Adjustability of the holder, achieved synchronously and automatically with the balancing weight.

The coupling of the sling arm drive and the cover in its Closing prevents access to the rotating sling arm. DRs timer element or a standstill monitor (e.g. centrifugal switch) prevents opening of the lid even while the centrifugal arm is running out.

The supply of measurement and power lines is also advantageous to the heating element through the motor axis, because it is not after the heating process The connections still need to be removed before the spinning process begins can be.

The invention is based on an illustrated embodiment described in more detail. They show: FIG. 1 a sling arm with muffle holder and leveling compound partly in section and FIG. 2 shows a complete cast-centrifugal machine partly on average.

On a drive shaft 1 of a cast centrifuge 33 is in a for A sling arm 2 in the form of a tube 3 is attached to the horizontal inclined plane. At the higher end of the pipe 4, a balancing mass 5 is provided, which on a consisting of different sections, rotatably mounted in tube 3 drive rod 6 is attached.

In the pipe end 4, the rod 6 is provided with a thread 7, which is in engagement with an internal thread 8 in the tube 3 and the rod 6 with the balancing mass 5 longitudinally displaceable connects.

At the opposite end of the arm 9, the drive rod 6 has circumferential Recesses 10, in which a gear 11 mounted on the arm 2 engages. Likewise At the end of the arm 9, a rack 12 is displaceable transversely, possibly inclined to the arm 2 arranged and is in engagement with the gear 11. At the upper end of the rack 12, which is laterally offset to the rod 6, is located essentially The muffle carrier 13 is aligned horizontally. A holder 14 is placed on the end 9.

A heating element is indicated in dash-dotted lines 15 with a crucible 16 and a pouring opening 17 and a heating coil 18 as well as a casting muffle 19 with a filling opening 20 on the muffle holder 13 shown. These elements do not form part of the invention and therefore do not become explained in more detail (Figure 1).

The cast spinner 33 is in a spinner 21 according to the figure 2 installed with a housing 22 and a cover 23. On the intermediate floor 24 is a drive motor 25, on whose shaft the drive shaft 1 of the sling arm 2 sits, flanged. The cover 23, hinged to the hinge 26, stands in Connection to a lid opener, e.g. a magnetic lock 27. From a control box 28, which includes a timer and the necessary relays for the motor 25 and the Contains magnetic lock 27 for the cover 23, the feed lines run to the aforementioned Drives and a main switch 29 with control lights on the front of the machine. On the drive shaft 1, a fan blade 30 and in the housing 22 ventilation slots 31 may be provided for circulating air through the housing 22.

The cover 23 preferably does not close the housing 22 tightly and leaves an air gap 32 free.

In the following, the function of the cast spinner is briefly described. An empty muffle 19 is placed on the holder 13 and the leveling compound 5 rotated until the muffle 19 at the height provided for it, which with the pouring opening 7 of the crucible 16 corresponds, has arrived. When turning the Leveling compound 5 moves it either outwards when a large muffle 19 is placed or inwards if a small muffle 19 is present. The slopes 7.8 as well as the tooth pitch on gear 11 resp.

the pitch of the grooves 10 and the teeth on the rack 12 are of course designed in such a way that the respective mass of the attached Muffle 19 a corresponding, an imbalance in the arm 2 preventing or greatly reducing Leveling compound facing.

The slight inclination of the arm 2 causes the center of gravity of the mass the muffle 19 essentially in the same plane of rotation as the center of gravity of the balancing mass 5 comes to rest or revolves. It can therefore not only be static, but above all a dynamic equilibrium can be achieved.

The cast centrifugal machine 21 in FIG. 2 mlt of the built-in cast centrifugal machine 33 according to FIG. 1 works as follows: When the cover 23 is open, the He winding 18 the metal located in the crucible 16 is melted.

If the operator determines (a measuring element can also be used are) that the necessary temperature is reached, the cover 23 is closed. Immediately after the cover 23 is closed, the motor 25 displaces the sling arm 2 in rotation for a time tl that can be set by the control. With the start of rotation the liquid metal is thrown through the opening 20 into the casting muffle and can freeze there. After the set time t1 has elapsed, the motor 25 switches off and after a further pre-set time t2 or by a standstill indicator (not shown) the cover 23 is opened by the magnetic lock 27.

The opening process can also be indicated acoustically or optically.

By testing and making markings beforehand can the suitable position for the leveling compound for the selected muffle size be determined and identified.

Claims (9)

Claims 1. Cast extractor especially for dental applications with a device to compensate for the imbalance in the case of different investment ring sizes, consisting of a sling arm attached to the end of a drive shaft, a arranged at one end of the sling arm substantially vertically displaceable Muffle holder and one slidably arranged along the other end of the throwing arm Leveling compound, as well as a melt melt, characterized in that the muffle holder (13) and the balancing mass (5) are in drive connection with one another in such a way that that when adjusting the muffle holder (13) to the size of the attached Muffle (19) the balancing mass (5) synchronously with the corresponding mass the muffle (19) compensating point on the throwing arm (2) is moved. 2. Casting centrifuge according to claim 1, characterized in that the Muffle holder (13) by turning the leveling compound stored in a thread (7, 8) (5) is infinitely adjustable. 3. Casting centrifuge according to claim 2, characterized in that as Drive connection between the muffle holder (13) and the leveling compound (5) gear (10, 11, 12) is provided in the lug arm (2). 4. Cast centrifuge according to claim 2 and 3, characterized in that the transmission from a firmly connected to the balancing mass (5), in the centrifugal arm (2) rotatable and longitudinally displaceable threaded rod via a thread (7, 8) (6) consists of circumferential grooves (10) and a gear (11) an am Muffle holder (13) attached to the throwing arm (2) so as to be adjustable in height Drives the rack (12). 5. Casting centrifuge according to claim 1, characterized in that the Throwing arm (2) inclined to the horizontal on the drive shaft (attached in this way is that the center of gravity of the balancing mass. (5) each essentially in the the same plane of rotation as the center of gravity of the mass of the muffle (19). 6. Automatic casting machine consisting of a casting machine, a housing with a cover and a drive that accommodates the cast spinner for the cast spinner, characterized in that the cast spinner (33) or their drive (25) with the cover via a timer in the control box (28) like that is coupled that by closing the lid (23) the drive (25) of the centrifuge (33) starts for an adjustable time tl and after Start of the time tl a further time t2 until the centrifuge comes to a complete standstill (33) passes before the cover (23) gives access to the centrifuge (33). 7. Automatic casting centrifugal machine according to claim 6, characterized in that that the time switch element (28) consists of a time relay or a time switch mechanism. 8. Automatic casting centrifugal machine according to claim 6, characterized in that that the cover (23) is driven by a drive (25) connected to the time switch element to open the lid (23) is connected. 9. Automatic casting centrifugal machine according to claim 6, characterized in that that a magnetic lock (27) is operated with alternating current and at the same time as acoustic opening indicator works. lO.Automatic casting centrifugal machine according to claim 6, characterized in that that the feeds for the heating of one arranged on the centrifugal arm (2) Crucible (16) and for the measuring elements through the drive shaft (1) are.