Electric heating – Heating devices – Tool or instrument
Reexamination Certificate
2002-11-01
2004-09-21
Jeffery, John A (Department: 3732)
Electric heating
Heating devices
Tool or instrument
C401S002000, C222S146500
Reexamination Certificate
active
06794612
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a modeling device for manually applying and modeling substances, namely wax, which are flowable when subjected to heat.
BACKGROUND OF THE INVENTION
Modeling devices are known per se in connection with various functions, in particular for various materials. One important application area relates to prosthodontics, in particular the application of wax to the crown region of a tooth to be modeled. It is known on the one hand such that by means of a modeling tip wax is received in a flowable consistency, i.e. it can be modeled in a plastic manner, and transferred to the crown region, where it is subsequently worked. As the spatial structures to be worked are relatively small, this activity requires that the wax to be applied is metered in an extremely precise manner. Also, it is laborious and time-consuming using a modeling tip for the flowable wax to be received and applied at a site which is remote from the processing location.
A modeling device is known from Dental-Labor XLVIII, Issue 4/2000, wherein a tank which receives a wax cartridge is provided within a modeling device and said tank can be heated electrically to the same extent as a modeling tip. A mechanical push button is used to meter the wax which issues out of the modeling tip and the modeling device is operatively connected to an energy supply unit.
A device for wax modeling cast models in dentistry is known from German Patent DE 94 12 336 U1, which device consists of an elongated, base body which is a similar shape to a writing device and which serves as a storage chamber for the wax and whose funnel-shaped end region is provided with an outlet orifice and a coupling part, onto which coupling part conventional modeling tips can be placed. The wax storage chamber is encompassed by electrically heatable heating elements in the form of a heating mat which is connected to a thermostat, adjusting elements and a display device. Once the entire wax storage chamber has been heated, a heat insulation layer is provided between the casing of the base body and the heating mat. The end region, remote from the modeling tip, of the base body serves to insert wax cartridges known per se into the wax storage chamber, wherein likewise a pneumatically operated piston-cylinder unit is inserted via this end region into the base body and forms a forward-feed drive. For control purposes, the device is provided with sensor buttons which are located on the front side end of the base body facing the modeling tip. Depending upon the temperature of the melted wax inside the wax storage chamber, it can be difficult to meter in a precise manner the wax to be dispersed. It is a drawback as far as the operating technology is concerned, that the end remote from the modeling tip is not only connected to lines for supplying compressed air but is also connected to lines for supply electrical energy. This not only impairs the view of the immediate working region of the modeling tip but precise movements are also difficult. A further unfavorable condition is the complete encasement of the wax storage chamber in a heat-insulating material, as this inevitably leads to an increase in the cross-sectional dimensions of the device.
A further comparable device is known from German Patent DE 33 46 254 A1, which device consists of an elongated base body, wherein the wax cartridges to be processed can be inserted either via the rear side end of the base body or via the front side end thereof, in other words, in each case having first dismantled the function elements located on these two ends. However, as a departure from the subject matter of the aforementioned DE 94 12 336 U1, only the frontal side end is heated, i.e. the end facing the modeling tip, so that there is no necessity to encase the wax storage chamber in a heat-insulating casing. The forward-feed drive used can comprise an electromotor or also a piston cylinder unit requiring a supply of compressed air. However, a disadvantage of this known device is also the condition that connection lines for supplying electrical energy and optionally also for supplying the compressed air are located on the rearside end, i.e. the end remote from the modeling tip. Finally, it is comparatively complicated to use a wax cartridge which is to be processed.
SUMMARY OF THE INVENTION
It follows from this that the object of the invention is to provide a modeling device in accordance with the generic type such that in addition to facilitating the handling of the modeling device, the metering of the substance to be applied and the application procedure as such are also facilitated. This object is achieved in the case of such a device by virtue of a stylus having a chamber and a closable opening therein for inserting a wax cartridge into the chamber, a piston being positioned within the chamber and connected to a spindle nut and a threaded spindle, the piston forming the force-transmitting member between the threaded spindle and the modeling substance, a cable from an energy supply being attached to a front region of the stylus facing a modeling tip positioned on the front region.
In a manner known per se, a motorized forward-feed drive for the substance to be processed is located inside the modeling device and the intended purpose of the said drive is to move this substance for processing in the direction towards the modeling tip. Morever, a heating device is provided, which is capable of heating the substance substantially only at the end of the device facing the modeling tip and in particular until it issues out of the outlet of the modeling tip. In other words, it is not the intention to heat the substance completely to render it all into a liquid state, which in addition to other disadvantages would not only be associated with a certain expenditure of time but would simultaneously also be associated with a corresponding expenditure of energy. Thus, only that region of the substance is heated which during the procedure of being applied to the crown region to be modeled, namely when exiting out of the said outlet, is subjected to plastic deformation and accordingly must be sufficiently flowable. Finally, a switching device is provided, which is connected directly to the modeling device and during the working procedure is subjected to the immediate influence of the user of the modeling device. This switching device serves to control both the forward feed drive and also the heating device. It is preferably provided that the forward feed rate can be continuously regulated within a fixed feed rate range which is tailored to suit the working process. The same applies for the heating device. In particular, the heat which is to be imparted into the substance being processed can preferably be regulated likewise within a fixed range. The user of the modeling device thus has the opportunity to control both the forward feed and also the consistency of the substance being processed in a manner tailored to suit the working step and also the characteristics of the substance.
In accordance with the invention, the base body of the modeling device or stylus is provided with an orifice which is intended for introducing the substance which is a solid body in its initial state. This orifice can be closed and any flap or closing mechanism which does not impair the handling of the modeling device may be used for this purpose.
The components of the forward feed drive in accordance with the invention are formed by an electromotor, a threaded spindle and a spindle nut, wherein for example the threaded spindle is mounted in a non-rotatable manner within the modeling device, so that a rotation of the spindle nut can generate a forward feed movement in the longitudinal direction of the modeling device. The rotational speed of the motor and the pitch of the threaded spindle are designed with respect to the control range of the forward feed rate. A piston which is connected to the threaded spindle serves to provide a large-surface force-transmitting element which is directly connected to the substance whi
Jeffery John A
Synnestvedt & Lechner LLP
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