MXPA98003366A - Mechanisms and process for covering threaded articles containing external configurations diver - Google Patents

Abstract

A mechanism and a process for coating threaded holes in special articles that have variable external configurations, for example metal punches. The special articles are placed in a pre-selected orientation in a loading station and then coupled to a hauling unit and moved from the loading station to the heating station, and subsequently to a spraying and discharging station. During movement between stations, the article is preserved in the preselected orientation to allow adequate heating and spraying of the threaded holes of the article.

Description

MECHANISM AND PROCESS FOR COVERING THREADED ARTICLES THAT HAVE DIVERSE EXTERNAL CONFIGURATIONS FIELD OF THE INVENTION This invention relates in general to a mechanism and a process for coating portions of articles having different external configurations. More specifically, the invention relates to the application of a thermoplastic layer for coating the threaded holes in special articles, for example metal punches.

BACKGROUND OF THE INVENTION It is well known to apply thermoplastic resin powders, for example nylon, in articles having threads to form a "patch" that retards the decoupling of the patterned fastener with a coupling fastener, as shown for example in the US Pat. the United States Nos. 3,787.22 and 3,858,262. Mechanisms have also been developed for applying a protective coating or coating to fasteners having standard internal threads at relatively high production speeds, as disclosed in U.S. Pat.

Nos. 4,888,214, exhibition of which is incorporated herein by reference. Similarly, others have been developed P1268 / 98MX mechanisms for coating the fasteners of both standard and non-standard types at lower production speeds, as disclosed in U.S. Patent Nos. 5,141,771 and 5,362,327, also incorporated herein by reference. A common feature of the fasteners described in the aforementioned patents is that they possess only a single tapped hole (eg, nuts) and their external dimensions are kept within narrow tolerances. There are many special items, for example metal die cuts, which contain several threaded holes and have a large variation of external dimensions. While the threaded or tapped holes of these special articles may also advantageously use the patch or protective coating described above, the prior art applicators for coatings or patches, including the mechanisms described in the aforementioned prior art patent applications, they typically use external dimensions to place the threaded holes with the center line of the corresponding spray nozzles. Unfortunately, this approach is impeded for most die-cut pieces, for example, whose external surfaces normally have P1268 / 98MX rough edges and burrs that prevent the precise placement of these edges. Previously, to achieve the coating of articles with various external dimensions, the coating had to be applied to the articles that had been manually placed, at correspondingly low production speeds. Therefore, it is desirable to provide an automated process and an automated mechanism for applying protective coatings or protective patches to the threaded holes of articles, which have different external configurations, also providing a considerable increase in production rates.

SUMMARY OF THE INVENTION The present invention retains the advantages of known methods and mechanisms for coating or patching threaded articles. It also solves the disadvantages thereof and provides new advantages not available with those mechanisms or methods, particularly when the threaded articles have external configurations of varying dimensions. The invention is generally directed to a process for using an automated coating and repositioning mechanism to apply a thermoplastic material to one or more threaded openings in a series of articles that P1268 / 98MX have variable external configurations. The process uses the openings of the articles, for example die-cut with tapped holes, to properly orient the article. A station is provided for the loading of each item. The charging station includes one or more pins, each dimensioned to receive one of the openings to be coated and placed in the corresponding position with respect to the locations of the openings. An article is provided to the loading station and the pins are seated within the openings of the article to define a preselected orientation of the article. A carrying unit is provided for coupling to the article and for moving it from the loading station to a heating station, while preserving the article in the preselected orientation. The heating station includes at least one heating element, for example, a channel-type induction coil with a pair of legs positioned adjacent to the travel path of one or more openings. The heating station is adapted to heat the openings to a temperature sufficient to melt a pre-selected thermoplastic resin applied to the selected threaded portions of the openings. After heating, the article is moved by the hauling unit to a spray station and P12G8 / 98MX download while holding the item in the preselected orientation. The thermoplastic resin is applied to selected portions of the openings and fuses and melts while the article is in the spray and discharge station. The article is ejected from the spray and discharge station and a second article is delivered to the loading station, and a thermoplastic material can be applied to successive articles, following this procedure. To facilitate this process, the hauler can return to the loading station during the spraying and / or ejection of the item. The distance between each pin is approximately equal to the distance between the horizontal legs of the induction coil, as well as the distance between the material applicators. The material applicators may be in the form of a spray nozzle if the thermoplastic material is in powder form, and the number of applicators preferably is equal to the number of pins. A mechanism for applying a thermoplastic coating to one or more threaded apertures in a series of articles having variable external configurations is also part of this invention. Once again, the openings are used to properly orient the threaded article. A charging station includes one or more P12S8 / 98 X pins, each dimensioned to receive one of the openings to be coated. The pins are located corresponding position to the locations of one or more openings. An article is provided at the loading station and a corresponding pin sits within at least one of the openings of the first article to define a preselected article orientation for that article. A carrying unit is used to couple the article and to move it from the loading station through the heating station, while the article is retained in the preselected orientation. The preheating station is positioned adjacent to the travel path of one or more openings and is adapted to heat the one or more openings to a temperature sufficient to melt a preselected thermoplastic resin applied to the selected threaded portions of one or more openings. A spraying and discharging station receives the first article that comes from the heating station while retaining it in the preselected orientation. In the spraying and discharging station, the thermoplastic resin is applied to the openings so that it melts and melts in at least the selected threaded portions of the openings, prior to the ejection of the article. In a similar way, successive articles are processed.

P1268 / 98MX BRIEF DESCRIPTION OF THE DRAWINGS The novel features that are typical of the present invention are set forth in the appended claims. The invention by itself, however, together with other objects and expected benefits will be better understood in relation to the following description taken with respect to the accompanying drawings, wherein: Figure 1 is a perspective view of a preferred embodiment of the invention; automatic mechanism for coating articles of the present invention; Figure 2 is a partial top view showing the movement of the article to be coated through the heating coil; Figure 3 is a view similar to Figure 2 showing the article during a coating application; Figure 4 is also a view similar to Figure 2, showing ejection of the coated article; Figure 5 is a perspective view of the article during ejection; Figure 6 is a side cross-sectional view taken along the reference line 6-6 of Figure 2, showing a different embodiment of the heating coil; and Figures 7 and 8 are opposite side views P1268 / 98MX of the mechanism shown in Figures 1 and Figure 6, taken along lines 6-6 and 7-7, respectively.

DESCRIPTION OF THE PREFERRED MODALITIES With items such as die-cut with threaded holes, the distance between these threaded holes is typically preserved to a very narrow tolerance. The present invention takes advantage of this fact to orient the article with respect to the data of a machine before coating the openings of the article with a thermoplastic material. Referring first to Figure 1, a mechanism generally designated 10, which forms the preferred embodiment of the present invention, is shown in that Figure. The mechanism 10 includes an upper frame, generally designated 16, firmly mounted to a lower frame, generally designated 15, by means of a rod 13. The height of the upper frame 16 can be adjusted relative to that of the lower frame 15. by means of a sliding bracket 14 (Figure 7) with respect to the rod 13, and then the holding bracket 14 with respect to the rod 13 for fixing the position (clamping mechanism not shown). The upper frame 16 includes a carrying unit, generally designated with the 21, which moves horizontally with respect to the fixed upper frame P1268 / 98MX in the direction of the arrows. The carrying unit 21 includes an upper bracket 22, a lower bracket 23 and a gripping unit 25. The gripping unit 25 moves vertically due to the vertical stroke of the rod 24 within the bracket 23. If desired, the unit The gripper 25 can also be rotated about the axis of the rod 24. The gripper unit 25 includes lugs 27 designed to hold and hold a blank 20 in a fixed orientation, relative to both the horizontal and vertical planes, during the movement of the die-cut piece The carrying unit 21 and the gripping unit 25 can be placed in four basic positions, marked "A", "B", "C" and "D" in Figure 1, and as will be described below. The support plate 17 is fixed to the wall 15A of the lower frame 15. The plates 18 and 19 are mounted to the blocks 18A, 19A and to the support cylinders 18B, 19B, respectively. The support plates 17 and 19 are mounted at approximately the same height, while the support plate 18 is mounted at a slightly higher height. The plate 17 includes openings for receiving material applicators, for example spray tube nozzles, as described below. The plate 18 supports opposed induction coils 30A, 30B (Figures 1-4) and plate 19 is provided with mounting bolts 61, P1268 / 98 X 62 (preferably as shown in Figures 6 and 8, only one induction coil 30 is used and this can be mounted on a plastic coil support, not shown. The mounting bolts 61 and 62 have, each a diameter that is smaller than the smaller diameter of the threaded holes 33 of the blank 20 (Figure 2) Of course, any number of pins, corresponding to the number of openings to be coated, can be used. between the pins 61 and 62 corresponds to the center line distance "X" between the threaded holes 33 in the blank 20 (Figure 2) This separation distance "X" is also approximately equal to the spacing between the induction coils front and rear 30A, 30B (Figure 3) as well as the distance between the spray nozzles 40A, 40B and the corresponding holes 17A, 17B on the support 17 for those spray nozzles (Figure 1). When the die-cut piece 20 is loaded on pins 61 and 62, it is placed precisely for both heating and spraying. During operation and referring to Figures 1-6, the blank 20 is initially loaded so that the holes 33 are placed on the pins 61 and 62 of the support plate 19, thus generating a signal that uses, for example , a sensor P1268 / 98MX photoelectric or a proximity switch. In response to the signal, the grip unit 25 moves horizontally from the position A to the position B, descends to the position C and the handles 27 close in the blank 20. The grip unit 25 carries at this time a the blank 20, and retracts to position B. In position B, the blank 20 is raised towards the center line between the horizontal legs of the induction coils 30 (Figure 6). As will be understood, the proper orientation of the threaded article facilitates localized treatment of the article in the area where the threaded openings are located. The grip unit then returns horizontally to the position A, thus causing the punched piece to pass between the upper and lower legs of the induction coil 30, heating the openings to the temperature suitable for melting the coating. When the heated die comes to the position A, the grip unit 25 then descends to the position D. In the position D, the handles 27 open and, with the help of a magnet located in the middle between the holes 17A, 17B on the plate 17 (not shown) deposit the plate of the blank 20 in the same orientation (in front of the tapped holes 33), here called the "spray position", same as the blank P1268 / 98MX 20 was when it was first held in position C, here called the "loading position". When the blank 20 is in the spray position, a signal is given to the Allenair cylinder 46 to terminate a cycle. This results in the spray blocks 36A, 36B sliding upwards relative to the L-shaped frame 26, thus causing the spray tubes 40A, 40B (Figure 1) to rise and enter the holes 33 of the die-cut piece 20 a mixture / air then passes through the powder supply tubes 37A, 37B in the direction of the arrow (powder feeder not shown) through the spray tubes 40A, 40B and over the threaded holes 33 , at the right time of the cycle. Excess powder spray collectors can be used and placed properly, as is well known in the art. After application of the coating, the spray tubes descend and exit the die plate, and the plate is ejected from the spray position, for example, using air under pressure, a cam mechanism or an air cylinder 70 ( Figure 8). The ejection of the coated die-piece preferably occurs at the moment when the grip unit 25 is moving and returning to the position C to engage the next article to be coated. After patching or coating the P1268 / 98MX threaded holes in the die-cut part, the die-cut part is ejected or discharged from the D-position. An air cylinder is preferably used for this purpose and the blanks 20 can be ejected into the discharge tube 50, as shown in FIG. Figures 1 to 4. In the preferred embodiment, the induction heating for the induction coil 30 is supplied by a Lepel induction generator LSS-15KW, 50 KHz at 200 KHz. The powder is supplied and dosed by an AccuRate Model 302 dry material feeder and is applied in the typical manner (refer for example to U.S. Patent No. 33,766). The application of liquid coatings can also be done using, for example, a liquid coating application device shown in Figures 9-16 of co-pending and co-assigned United States applications, serial No. 08,779,684, filed on 7 January 1997 and titled "Method and Apparatus for Applying a Coating to the Head / Trunnion Union of Externally Threaded Fasteners", the exposition of which is incorporated herein by reference. The movements of the mechanism, 10 can be controlled by a GE Fanuc Micro Programmable Logic Controller, Series 90 TM. The signals can be provided by a combination of proximity sensors and controls P1268 / 98MX photoelectric. By using the automated mechanism of the present invention, the threaded holes of the blanks with variable external configurations have been coated at rates exceeding previously possible rates of manual processing. Various materials can be used to coat or patch punched holes, including polyamide resins such as nylon, polyphthalamide resin such as NYTEMP® which is obtained from Nylok Faster Corporation, NYCOTE® powder (also obtained from Nylok), and other fluoropolymers or thermoplastics, either in liquid or powder form. It will be evident to those with skill in this field that depending on the particular coating material selected, its purposes and the manner in which it is applied (ie powder or liquid), the technician may choose to employ heating either before or after the application of the coating or during both periods. It will be understood that the invention can be incorporated in other different forms without departing from the spirit or central characteristics thereof. Therefore, although a specific embodiment designed to apply a contaminant-inhibiting coating and protector to the tapped holes of die-cut parts has been disclosed, it will be appreciated that the principles of P1268 / 98MX invention can be advantageously employed to provide, for example, a patch of polyamide resin (eg nylon) or polyphthalamide to the threaded openings of blanks or other articles as well. The modalities and examples herein must therefore be considered in all respects as illustrative and not exclusive, and the invention should not be limited to the details provided herein.

P1268 / 98 X

Claims (18)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following CLAIMS is claimed as property: 1. A process that uses an automated placement and coating mechanism to apply a thermoplastic material to one or more threaded openings- in a series of articles having variable external configurations, which use the openings to properly orient the mechanism, which comprises the steps of: a. providing a station for loading each article, the loading station includes one or more pins, each sized to receive one of the openings to be coated, the one or more pins being placed in position corresponding to the locations of the one or more openings; b. providing a first article at the loading station and seating a corresponding pin within one or more openings of the first article to define a preselected orientation of the article; c. providing a carrying unit for attaching to the first article and moving the article from the loading station to the heating station, while keeping the article in orientation P1268 / 98MX preselected, the heating station includes at least one heating element positioned adjacent to the travel path of one or more openings and adapted to heat the one or more openings to a temperature sufficient to melt a pre-selected thermoplastic resin applied to the selected threaded portions of one or more openings; d. after heating the one or more openings, moving the first article by the hauling unit to a spraying and discharging station, while keeping the first article in the preselected orientation; and. applying the thermoplastic resin to at least selected portions of the one or more openings to thereby melt and fuse the resin in the selected portions of the one or more openings, while the first article is in the spray and discharge station; F. eject the first item from the spray and discharge station; g. supply a second item to the loading station; h. Repeat steps b through g to apply the thermoplastic material to the threaded openings of other articles. P1268 / 98MX 2. The process according to claim 1, wherein the steps f and g are carried out simultaneously. 3. The process according to claim 1, further comprising the step of returning the hauler to the loading station in response to a signal indicating that step g has already been carried out. The process according to claim 1, further comprising the step of returning the hauler to the loading station simultaneously with the development of step e. The process according to claim 1, wherein the thermoplastic material is applied using a number of spray nozzles equal to the number of openings. The process according to claim 5, wherein each spray nozzle is inserted into a corresponding threaded opening of the fastener. The process according to claim 5, wherein the distance between each pin is equal to the distance between the spray nozzles. 8. The process according to claim 1, wherein step f is effected using an air cylinder. The process according to claim 1, wherein at least one of the heating elements comprises a channel-type induction coil, and wherein the P1268 / 98MX distance between each pin is approximately equal to the distance between the horizontal legs of the coil. The process according to claim 1, wherein the thermoplastic material forms a substantially uniform fluoropolymer coating and which inhibits contaminants and is protective. The process according to claim 1, wherein the thermoplastic material comprises a nylon patch. 12. A process that uses a positioning and coating mechanism to apply a thermoplastic material to one or more threaded openings in a series of articles that have variable external configurations, using the openings to properly orient the mechanism, which comprises the steps of: a. loading an article using one or more pins, each sized to receive one of the openings to be coated, the one or more pins are placed in position corresponding to the locations of the one or more openings, where a corresponding pin is seated within the one or more openings of the first article to define a preselected orientation for the article; b. provide a carrying unit to attach to the article and move it while retaining the P12G8 / 98MX first item in the preselected orientation, to a spray location where the thermoplastic resin can be applied to at least the selected portions of the one or more openings; c. using the carrying unit to move the article from the spray location to a heating station, while the article is kept in the preselected orientation, the heating station includes at least one heating element positioned adjacent to the travel path of one or more openings and adapted to heat the one or more openings to a temperature sufficient to melt and fuse the thermoplastic resin previously applied to the selected portions of one or more openings; d. Repeat steps a through c to apply the thermoplastic material to the openings of other items. 13. A mechanism for applying a thermoplastic coating to one or more threaded openings in a series of articles having variable external configurations, using the openings to properly orient the mechanism, comprising: a loading station that includes one or more pins, each one sized to receive one of the openings to be coated, the one or more pins are placed in position corresponding to the locations of the P1268 / 98 X one or more openings, wherein at least two corresponding pins seat within at least two openings of the article to define a preselected article orientation for the article; a carrying unit for attaching the article and moving it from the charging station to a heating station, while keeping the article in the preselected orientation, the heating station is positioned adjacent to the travel path of one or more openings and is adapted to heat the one or more openings to a temperature sufficient to melt a pre-selected thermoplastic resin, applied to the selected threaded portions of one or more openings; and a spray and discharge station for receiving the article from the heating station while being kept in the preselected orientation, for applying the thermoplastic resin and thus melting and fusing the resin in at least the selected threaded portions of the one or the most openings, and to eject the article from the spray and discharge station. The mechanism according to claim 13, wherein the carrying unit is adapted to return to the loading station and to attach another article to be coated at the same time that a coated article is ejected from the spraying and unloading station. P1268 / 98MX 15. The mechanism according to claim 13, wherein the carrying unit is adapted to return to the loading station at the same time that the resin is being applied to the one or more threaded openings of an article. The mechanism according to claim 13, wherein the spraying and discharging station includes tapping nozzles which are placed within a corresponding threaded opening to be coated, and which are operated in a periodic manner. 17. The mechanism for applying a thermoplastic coating to one or more threaded openings in a series of articles having variable external configurations, using the openings to properly orient the mechanism, comprising: a loading station that includes one or more pins, each one sized to receive one of the openings to be coated, the one or more pins are located in positions corresponding to the locations of the one or more openings, wherein a corresponding pin sits within at least two openings of the article for define a preselected article orientation for that article; a carrying unit for coupling the article and moving it while it is kept in the preselected orientation; P12S8 / 98MX a spray station to apply the thermoplastic coating to at least selected threaded portions of the one or more openings; and a heating station positioned adjacent to the travel path of the one or more openings and adapted to heat the one or more openings to a temperature sufficient to melt the thermoplastic coating previously applied to the selected threaded portions of the one or more openings, wherein the carrying unit is used to move the coated article from the spray station to the heating station. 18. A mechanism for applying a thermoplastic coating to one or more threaded openings in a series of articles, having variable external configurations, using the openings to properly orient the mechanism, comprising: a loading station having one or more pins , each sized to receive one of the openings to be coated, the one or more pins are positioned corresponding to the locations of the one or more openings, wherein a corresponding pin seats within at least two openings of the article to define a preselected orientation for that article; P12G8 / 98MX means for coupling the article and moving it from the loading station adjacent to the heating means, while preserving the article in the preselected orientation, the heating means is adapted to heat the one or more openings at a sufficient temperature for melting the pre-selected thermoplastic resin applied to the selected threaded portions of the one or more openings; and a means for preserving the heated article in the preselected orientation and for applying the thermoplastic resin to thereby melt and fuse the resin in at least the selected threaded portions of the one or more openings. P1268 / 98MX