Patent Application
20200094456
The present application relates generally to carriers for root canal obturation, and, more particularly, to a self-driven apparatus and method for concentrically overmolding Gutta-Percha onto a carrier.
During fabrication of dental products like carriers, silicon blocks with cavities having the shape of the dental product may be used wherein overmolding material may be manually inserted into the cavities of the silicon block. The silicon block may then be heated for a time period, for example, several hours for gutta-percha, to melt the material into the cavities. Carriers may subsequently be manually inserted into the silicon block and held in place with for example aluminum blocks so that the molten gutta-percha may encapsulate a part of the inserted carrier. The silicon block may then be cooled down and the carrier removed after the molten gutta-percha has solidified around the carrier. A problem with this method however is that the manual process is time consuming and expensive. Moreover multiple people may be needed for this process. Further the process is prone to human errors and in many cases, the gutta-percha may not be overmolded concentrically around the carrier due to the molten gutta-percha taking a path of least resistance and flowing non-uniformly in the mold.
U.S. Pat. No. 5,147,657 discloses a retractable pin and an injection mold machine for golf balls wherein the mold positions gates at each pole of each mold cavity making balancing less critical and reducing shifting of cores during molding operations.
U.S. Pat. No. 6,129,881 discloses a retractable sleeve for a golf ball injection mold, wherein the retractable sleeve may be used to fabricate a golf ball cover or intermediate layer with improved durability in a high volume production environment.
U.S. Pat. No. 7,223,085 provides a mold and method for forming a golf ball with at least a core. The mold and method may comprise or use members with projections for forming multiple dimples on the core. The members may be retractable pins or sleeves or vent pins. In the case of the retractable pins, sets of pins with multiple dimple projections on the ends thereof are used to center the golf ball core within the mold. The members may also have circular or non-circular cross-sections so that the dimple-forming projections can conform to any dimple pattern.
US Patent No. US20010048180 teaches a device including first and second hemispherical mold halves that may form an interior cavity where an injection molding process may occur. A plurality of retractable pins may be used to support a core within the mold cavity. The first and second mold halves may further include a plurality of sub gates. Which may be connected to a runner system for delivery of a fluid stock material into a void of the cavity.
U.S. Pat. Nos. 5,201,523, 6,093,360, 3,919,774, 6,441,741, 2,301,338 and 5,240,397 disclose other methods which may be use in injection molding processes.
Existing limitations associated with the foregoing, as well as other limitations, may be overcome by a method and apparatus for concentrically overmolding gutta-percha onto carriers. Herein, to prevent excessive stress on the carriers 10 during overmolding, the production cycle may be divided into one or more stages with corresponding retractable pins of the stages such that one or more overmolded carriers may be produced to save time and increase accuracy and repeatability of the cycles. Moreover the apparatus may also be configured to injection mold the one or more carriers.
In an aspect of the present invention a method for concentrically overmolding one or more gutta-percha materials onto one or more corresponding gutta-percha carriers in stages is disclosed, the method comprising: for each stage: obtaining desired/predetermined dimensions of one or more gutta-percha materials (and/or layers of gutta-percha materials) to be overmolded onto one or more corresponding gutta-percha carriers; altering a size of cavities of one or more corresponding molds based on the obtained desired dimensions; centrally positioning the one or more corresponding gutta-percha carriers in the one or more corresponding molds using one or more corresponding retractable pins such that the one or more corresponding gutta-percha carriers are evenly spaced or substantially evenly spaced from inner walls of said cavities; and concentrically overmolding the one or more gutta-percha onto the one or more corresponding gutta-percha carriers.
In another aspect of the present invention, the method comprises one or more of the following features: (i) wherein the number of stages is based on characteristics of the corresponding gutta-percha carriers, (ii) wherein the characteristics include length, thickness and/or strength, (iii) wherein a diameter of gutta-percha overmolded at a tip of the one or more gutta-percha carriers is about 0.09 mm, (iv) wherein the method further comprises altering a size of cavities of one or more corresponding molds through (a) retractably and/or (b) manually changing the molds.
In another aspect of the present invention, an apparatus for concentrically overmolding one or more gutta-percha onto one or more corresponding gutta-percha carriers in stages is disclosed, the apparatus comprising: one or more corresponding molds configured to receive one or more corresponding gutta-percha carriers; one or more retractable pins configured to centrally position the one or more corresponding gutta-percha carriers in one or more corresponding cavities of the one or more corresponding molds such that the one or more corresponding gutta-percha carriers are evenly spaced or substantially evenly spaced from inner walls of the one or more corresponding cavities; and a processor configured for each stage to: obtain desired dimensions of the one or more gutta-percha to be overmolded onto the one or more corresponding gutta-percha carriers; and concentrically overmold the one or more gutta-percha onto the one or more corresponding gutta-percha carriers.
In another aspect herein, the apparatus includes one or more of the elements: (i) wherein the number of stages is based on characteristics of the one or more corresponding gutta-percha carriers, (ii) wherein the characteristics include length, thickness and/or strength, (iii) wherein the one or more corresponding molds has a horseshoe-shaped cavity at one end of the one or more corresponding molds for overmolding gutta-percha onto a tip of the one or more corresponding gutta-percha carriers such that pressure on said tip of the one or more corresponding gutta-percha carriers is minimized, (iv) wherein the one or more corresponding molds is changeable, (v) wherein the one or more corresponding molds includes a retractable insert, (vi) wherein the apparatus further comprises one or more corresponding gates at each stage configured to direct molten gutta-percha into the one or more corresponding cavities to overmold the one or more gutta-percha, (vii) wherein the one or more retractable pins are configured to be concentric around the one or more corresponding molds such that the one or more corresponding gutta-percha carriers are positioned centrally.
In yet another aspect herein, the apparatus the apparatus includes: one or more corresponding molds configured to receive one or more corresponding gutta-percha carriers; one or more retractable pins configured to centrally position the one or more corresponding gutta-percha carriers in one or more corresponding cavities of the one or more corresponding molds such that the one or more corresponding gutta-percha carriers are evenly spaced or substantially evenly spaced from inner walls of the one or more corresponding cavities; wherein the one or more corresponding molds is constructed to seal off a predetermined portion of the one or more corresponding gutta-percha carriers such that an exposed portion of the one or more corresponding gutta-percha carriers is concentrically overmolded.
Further features and advantages, as well as the structure and operation of various embodiments herein, are described in detail below with reference to the accompanying drawings.
Example embodiments will become more fully understood from the detailed description given herein below and the accompanying drawings, wherein like elements are represented by like reference characters, which are given by way of illustration only and thus are not limitative of the example embodiments herein and wherein:
Different ones of the Figures may have at least some reference numerals that are the same in order to identify the same components, although a detailed description of each such component may not be provided below with respect to each Figure.
In accordance with example aspects described herein a method and apparatus may be provided wherein a shape, structure and dimensions of gutta-percha may be configured into cavities of a mold having one or more retractable pins 22 for concentrically overmolding the gutta-percha 11 onto one or more carriers 10. Herein, the apparatus may preferably be automated/self-driven to concentrically overmold one or more gutta-percha materials and/or layers of one or more gutta-percha materials 11 onto one or more carriers 10 for dental use and the retractable pins may be preferably pressure sensitive, though not required. Moreover, to prevent excessive stress on the carriers 10 during overmolding, the production cycle may be divided into one or more stages (e.g. between 1-12 stages, e.g. 4 stages) with corresponding retractable pins such that one or more overmolded carriers may be produced in a short time. In an embodiment herein, a duration for a production cycle may be, for example, between 12-30 seconds (e.g. 24 seconds). In another embodiment, a duration for a stage may be, for example, between 3-9 seconds (e.g. 6 seconds). In a further embodiment a number of carriers being worked on per stage may be, for example, between 1 and 16 carriers 10 (e.g. 8 carriers 10) and a number of finished carriers per production cycle may be, for example, between 1 and 64 carriers 10 (e.g. 32 carriers 10) may be produced per production cycle. The apparatus 14 may also be configured to injection mold the one or more carriers 10.
Referring to
The apparatus 14 may also include a means (e.g. a mechanically, pneumatically, hydraulically and/or electrically operated means) for turning/rotating the apparatus 14 through a predetermined angle (e.g. 90° about the Z axis or e.g. any angle between 0° and 360° to a stage/location (for example quadrant A, B, C, D) where a predetermined shape or section of the carrier 10 and/or gutta-percha 11 may be injection molded and/or overmolded respectively. A number of stages/locations may be based on characteristics of the carrier to be made such as length, thickness and strength of gutta-percha and or carrier. For example, a longer carrier may require more stages of gutta-percha overmolding than a shorter carrier may require such that the gutta-percha may be overmolded incrementally without putting excessive pressure on the carrier 10 (to minimize pressure exerted on a part or whole of the carrier 10).
A series of gates 30-33 and runners 40 proximal to said gates 30-33 (for example as shown in
In an embodiment according to the present invention, the mold 20a (as shown in
In another embodiment according to the present invention, the apparatus 14 may include a computer system 100 having a processor for providing consistency and repeatability and accuracy in the operation of the apparatus 14. The processor may monitor and controls the processing parameters, including for example the temperature, pressure, injection speed, retraction of retractable pins, and the like. The process control may have a direct impact on the overmolded carrier 10 and may range from a simple relay on/off control to a complex closed-loop control using for example servomotors (not shown) to provide position/speed feedback.
Having described an apparatus 14 for concentrically overmolding gutta-percha 11 onto carriers 10, reference will now be made to
The computer system 100 may include at least one computer processor 122 that may be used to ensure a consistency of the quality of injection molded and overmolded parts. Herein parameters such as cavity pressure, rotation speed and temperature of molten material, mold data, quadrant/location data, timing data etc. may be monitored and controlled according to predetermined criteria. Moreover the parameters may be displayed on a display unit 128 of the computer system 100 wherein the parameters may be changeable. The computer processor 122 may include, for example, a central processing unit, a multiple processing unit, an application-specific integrated circuit (“ASIC”), a field programmable gate array (“FPGA”), or the like. The processor 122 may be connected to a communication infrastructure 124 (e.g., a communications bus, or a network). In an embodiment herein, the processor 122 may receive an indication that a production cycle has been initiated by a use and may load instructions from memory or a control panel (display unit 128) concerning a number of overmolded carriers to be produced and may begin the production cycle as described in the methods herein.
A user interface 126 may forward video graphics, text, and other data from the communication infrastructure 124 (or from a frame buffer (not shown)) for display on the display unit 128. For example, the user interface 126 may include a video card with a graphics processing unit.
The computer system 100 may also include an input unit 130 that may be used by a user of the computer system 100 to send information to the computer processor 122. In one exemplary embodiment herein, the input unit 130 is a finger or stylus to be used on a touchscreen interface of the display unit 128. The input unit 130 may alternatively be another input device such as a keyboard or stylus. In one example, the display unit 128, the input unit 130, and the computer processor 122 may collectively form a user interface 126.
One or more steps of overmolding gutta-percha 11 onto carriers 10 may be stored on a non-transitory storage device in the form of computer-readable program instructions. To execute a procedure, the processor 122 loads the appropriate instructions, as stored on a storage device, into memory and then executes the loaded instructions.
The computer system 100 of
In further alternative embodiments, the secondary memory 134 may include other computer-readable media storing computer-executable programs or other instructions to be loaded into the computer system 100. Such devices may include a removable storage unit 144 and an interface 142 (e.g., a program cartridge and a cartridge interface); a removable memory chip (e.g., an erasable programmable read-only memory (“EPROM”) or a programmable read-only memory (“PROM”)) and an associated memory socket; and other removable storage units 144 and interfaces 142 that allow software and data to be transferred from the removable storage unit 144 to other parts of the computer system 100.
The computer system 100 also may include a communications interface 146 that enables software and data to be transferred between the computer system 100 and external devices. Such an interface may include a modem, a network interface (e.g., an Ethernet card or an IEEE 802.11 wireless LAN interface), a communications port (e.g., a Universal Serial Bus (“USB”) port or a FireWire® port), a Personal Computer Memory Card International Association (“PCMCIA”) interface, Bluetooth®, and the like. Software and data transferred via the communications interface 146 may be in the form of signals, which may be electronic, electromagnetic, optical or another type of signal that may be capable of being transmitted and/or received by the communications interface 146. Signals may be provided to the communications interface 146 via a communications path 148 (e.g., a channel). The communications path 148 carries signals and may be implemented using wire or cable, fiber optics, a telephone line, a cellular link, a radio-frequency (“RF”) link, or the like. The communications interface 146 may be used to transfer software or data or other information between the computer system 100 and a remote server or cloud-based storage (not shown).
One or more computer programs or computer control logic may be stored in the main memory 132 and/or the secondary memory 134. The computer programs may also be received via the communications interface 146. The computer programs may include computer-executable instructions which, when executed by the computer processor 122, cause the computer system 100 to perform the methods as described hereinafter. Accordingly, the computer programs may control the computer system 100 and other components of the device and system for modeling and visualizing a dental solution.
In another embodiment, the software may be stored in a non-transitory computer-readable storage medium and loaded into the main memory 132 and/or the secondary memory 134 of the computer system 100 using the removable-storage drive 138, the hard disk drive 136, and/or the communications interface 146. Control logic (software), when executed by the processor 122, causes the computer system 100, and more generally the apparatus 14 for concentrically molding gutta-percha 11 onto carriers 10, to perform all or some of the some of the methods described herein.
Implementation of such other hardware arrangement so as to perform the functions described herein will be apparent to persons skilled in the relevant art(s) in view of this description.
Having described an apparatus 14 for concentrically overmolding Gutta-Percha 11 onto a carrier 10 reference will now be made to
In a first stage of one production cycle as shown
The processor may then rotate the apparatus 14 along with the molds 20 through a predetermined angle, for example 90° to a second quadrant, B as shown in
The apparatus may then be rotated in a predetermined manner to a third quadrant, C, as shown in
The apparatus may then be rotated to a fourth quadrant, D, as shown in
It will be apparent to persons skilled in the art that various changes in form and detail can be made therein (e.g., locations/quadrants of the apparatus, angles of rotation, mold shapes and the like so as to perform the functions described herein and/or to meet dimensional requirements of overmolded dental carriers) without departing from the spirit and scope of the present disclosure.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety to the extent allowed by applicable law and regulations. The disclosure may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the present embodiments be considered in all respects as illustrative and not restrictive. Any headings utilized within the description are for convenience only and have no legal or limiting effect.
