FIELD OF INVENTION

The invention relates to a system and a method for coating elastomeric articles. More particularly, the invention relates to an automated system for offline coating the inner or donning side of medical examination and surgical gloves without inverting the gloves.

BACKGROUND OF THE INVENTION

Medical examination and surgical gloves are typically coated with a polymer or material solution internally or externally to provide enhanced properties to the glove, such as ease of donning, enhanced grip, minimized friction, enhanced skin hydration, and skin protection from microbes. The coating may be administered to the donning or interior side of the glove via the online glove dipping process or alternatively by an offline manual process.

The current preferred coating system used in the glove industry is manually spraying each glove using spray guns, or inverting the glove and coating it using washer type machines or ball mill type machines, or inverting the glove and spraying the coating or polymer solution to a selected batch of inverted gloves while being dried in a tumble dryer. The major drawback of using these individual manual spraying techniques is the time consumed for coating the glove. Besides, the bulk coating methods in coating machines/ ball mills or tumble driers result in inconsistent coatings, which vary alarmingly from glove to glove.

Accordingly, it is desirable to implement an automated system for coating elastomeric articles that can solve the problems mentioned above in a complimentary manner to glove dipping production and critically saves time and labor. The described invention provides such a system.

PRIOR ART

US6887542B2 discloses a method by Kimberly Clark Worldwide Inc, demonstrating treatment of a surface of an elastomeric article. The method includes providing a substrate having a treatment, providing an elastomeric article with an exposed surface, placing the article and the substrate into a tumbling apparatus, and tumbling the article with the substrate so that the treatment is transferred from the substrate to the exposed surface. The coating method further includes inversion of the article to expose the interior surface and to tumble the article with a second substrate on the interior surface. This glove coating method does not adhere to a specific technique of applying the offline coating treatment, and hence the resulting coating quality may not be consistent and uniform.

On the other hand, the current invention is an automated system designed to apply a coating material on the inner or donning side of medical examination and surgical gloves using an offline non-dipping and non-tumbling coating technique. The system does not require inversion of the article like the other conventional coating techniques. Instead, it involves glove inflation and is designed to apply a consistent uniform coating onto the inner side of the glove, spread across the glove's finger, palm, and cuff region via a pre-determined targeted technique. Hence, it is material efficient and both time and labor-saving.

SUMMARY OF INVENTION

In the first aspect of the invention, an automated system is provided for coating elastomeric articles, particularly medical examination and surgical gloves. The system comprises a mandrel on which the gloves are loaded onto the holders in each station, wherein the mandrel consists of several stations, with each station having individual holders onto which the gloves are loaded. Each holder possesses a capacitive sensor to detect the presence of the glove through electrical wavelengths upon loading. Each holder is connected to different valves, which are a spray valve, a coating solution valve, a blow valve and an air valve, wherein the spray valve and the coating solution valve are interconnected. The spray valve is connected to a spray nozzle at one end to distribute the misty form of coating material solution, and the coating solution valve is connected to a coating material tank for carrying liquid coating solution and distribute it also via the spray nozzle. The blow valve is connected to a blow nozzle at one end to blow the glove to an expected size, and an air valve is connected to an air regulator, which is fixed to the air tank or cylinder. The air flowing through the valve is precisely controlled by the pressure fixed on the air regulator.

In the second aspect of the invention, the entire coating process on the mandrel is automated and controlled by a control panel fixed next to the mandrel, wherein the control panel provides all the instructions needed for the coating system to operate automatically and checks on the availability and status of each holder in the respective stations on the mandrel. There is software installed in the control panel that detects the signals transmitted from the sensors installed in each holder to update the availability and status of the holder for glove loading.

Preferably, the availability and status of the holders in all the stations are updated in real-time, which can be monitored and controlled via the menu and content bar of the software installed on the control panel.

In the third aspect of the invention, the coating process on the mandrel is divided into five distinct phases that every glove goes through, starting from the loading onto the holder up to the ejection of the finished gloves from the holder. In the first phase, the gloves shall be loaded onto the available holders.

Then the gloves enter the second phase, where they are locked tightly onto the opening (mouth) of the holder via a lock valve, mimicking a vacuum seal of the glove.

An air pressure sensor on the holder measures the amount of air pressure applied on the cuff area of the glove and emits a signal to the control panel, confirming the tight seal of the glove onto the holder. After that, the gloves enter the third phase, where the air valves are automatically opened.

Preferably, once the air valve has been activated, a fixed amount of air at a predetermined pressure shall fill the gloves to a pre-determined size.

Preferably, the air pressure inside the glove is maintained at the pre -determined level by the air regulator connected to the air valve.

Preferably, the gloves are inflated with the incoming air up to 50-150% of its original size. Alternatively, the gloves can also be inflated with the incoming air to 0-50% or 150- 200% of its original size.

Once the gloves have been inflated to the pre -determined size, the air pressure sensor on each of the holders sends a signal to the control panel, wherein the air valve controlling the airflow is automatically shut down. The mandrel’s inflated gloves then enter the fourth phase, where the gloves are sprayed with a coating material using the mist spray technology. The sizes of the spraying nozzle have been precisely controlled to distribute the coating on a similar trajectory, ensuring a uniform coating of the gloves, covering difficult locations like a finger, fingertips, and crotch area. More particularly, a precision spray control technology is administered to ensure uniform coating by controlling the flow rate of the coating material through electrically-actuated spray nozzle on/off functionality. The on/off cycling is quick enough to ensure a constant material flow through the nozzle. Besides, with the precision spray control technology, the spray angle of the nozzle and the drop size of coating material produced remain unchanged, which further ensures the uniform application of coating material on the inner glove surface. In addition, the spray nozzle is uniquely designed to incorporate anti-bearding tips capable of atomizing the coating material into a fine mist through collision with air particles, similar to that of the air spray gun operating mechanism. The volume of the coating material applied each time has been fixed to distribute the same amount of coating material to all the gloves. However, the chemical properties of the coating material may vary in terms of specific gravity, temperature, viscosity, and surface tension which may affect the spray quality and uniformity of coating on the inner glove surface. Hence, to better optimize and control these variations, different spray patterns have been administered, including but not limited to the hollow cone, full cone, flat spray, and solid stream.

Once the gloves have been coated up to a pre-determined amount of coating material, a moisture sensor on the holder detects the glove surface wetness and sends a signal to the control panel, wherein the spray valve controlling the opening of the spray nozzle is automatically shut down.

In one embodiment, the mandrel’s coated gloves enter the final phase, where the gloves are loosened from the holder and automatically ejected into a collecting bucket, trolley, or conveyor for further processing and/or packing. The coated gloves are collected and tumble-dried before being packed.

In another embodiment, the mandrel’s coated gloves enter the final phase, where they are inflated with a pre-determined amount of hot air and left to dwell for a specified time until the coating material on the inner side of the gloves completely dries up in-situ on the mandrel. Once the inner coating material dries up, the hot air is gradually released from the gloves. The gloves are then loosened from the holder and automatically ejected into a collecting bucket, trolley, or conveyor for further processing and/or packing. In this case, the coated gloves need not be tumble-dried before packing.

In another embodiment, the mandrel’s coated and dried gloves are filled with predetermined amount of air again via the blow valve to help detect pinholes and/or defects in the gloves. Preferably, the gloves are inflated with the incoming air up to 50-150% of its original size. Alternatively, the gloves can also be inflated with the incoming air to 0-50% or 150-200% of its original size. Further, a beam of light is spread across the inflated gloves to aid the visual inspection for defects. Typical defects are glove thinning, discoloration, oil stains, white and black spots and the presence of particles such as dust, hair and so on.

If no pinhole and/or defect is detected, then the air inside the gloves is released. The gloves are then loosened from the holder and automatically ejected into a collecting bucket, trolley, or conveyor for further processing and/or packing. In this case, the coated gloves need not be tumble-dried before packing.

If a pinhole and/or defect is detected in gloves, the air pressure sensor on the respective glove holder detects the air leakage inside the inflated glove and emits signals to the control panel and prompts for preliminary auto-ejection of the gloves with pinholes and/or defects. These defective gloves are then loosened from the holder and ejected separately into a particular bucket that collects gloves with pinholes and/or defects.

In the fourth aspect of the invention, the coating process can also be done via manual handling of the mandrel and the control panel. The machinery parts that make up the coating system during the manual operation, such as the motor, pump, and pump valves, are activated separately from the control panel. The motor is activated to turn on the spinning of the rotary drum at a pre-determined speed to aid the manual loading of the glove onto the holder on the desired stations. The pump is activated to distribute the coating material from the tank into the pump valves, wherein the pump valves are activated to initiate the flow of coating material from the outlet of the pump valve into the inflated glove on the holder.

Each station can be handled separately, wherein the valves connected to the holders of each station can be turned on or off via the switch on button located on the control panel. Every station located on the mandrel carries the same function, whereas every holder located on the station carries the same function. The valves on each holder, which can be separately handled from the control panel, include the coating solution valve, the spray valve, the blow valve, and the lock valve. The coating solution valve is typically activated to open the coating solution valve to the spray nozzle, wherein the spray valve is activated to open the spray (misty) valve to the spray nozzle. On the other hand, the blow valve is activated to open the air valve to the blow nozzle, wherein the lock valve is activated to lock or seal the glove to the mouth of the holder. The valves located on each holder can be handled in several combinations. In one embodiment, the coating solution valve and the blow valve can be activated together to initiate the flow of a stream of liquid coating material released from the spray nozzle. In another embodiment, the coating material valve and the blow valve can be activated along with the spray valve to initiate the flow of mists that carries the combination of air and material particles. The spray valve and coating solution valve are interconnected. When a liquid form of coating is required, the coating solution valve is activated. When a misty form of coating is required, the spray valve is activated. The spray valve carries both air and coating material solution together in the same channel and distributes via the spray nozzle. The coating solution valve carries liquid coating solution and distributes also via the spray nozzle.

In addition, the duration to inflate the glove and deflate the glove by blowing off or releasing the air inside can be controlled from the control panel for every station. Besides, the duration to spray the coating material solution on the inner side of the glove can be controlled from the control panel for every holder. On the other hand, the dwell time of hot air used for in-situ drying, the amount of air used for pinhole detection, and the duration of visual inspection can also be controlled from the panel for every holder. The mandrel can also be manually positioned from the control panel by instructing the horizontal or vertical rotary drum to spin until it reaches the desired location of the stations to load the gloves.

BRIEF DESCRIPTION OF THE DRAWINGS

To facilitate a better understanding of the invention, there is illustrated in accompanying drawings the preferred embodiments from an inspection of which, when considered in connection with the following description, the invention, its construction and operation, and many of its advantages would be readily understood and appreciated.

Fig. 1A Is a schematic diagram illustrating a top view of a horizontally orientated system 010 for coating elastomeric articles such as gloves;

Fig. IB is a schematic diagram illustrating a side view of a vertically orientated system 010 for coating elastomeric articles such as gloves;

Fig. 2 is a schematic diagram illustrating a top view of the horizontal oriented system 010 comprising four holders 021 in each station 012 for holding elastomeric articles such as gloves; and Fig. 3 is a schematic diagram of a system 010 illustrating a phase-by-phase of automated operation for coating elastomeric articles such as gloves.

DETAILED DESCRIPTION OF THE INVENTION

The invention is now be described in greater detail, by way of example, with reference to the drawings.

Referring to Fig. 1A and IB, a system 010 for coating elastomeric articles as illustrated therein comprises a horizontal or a vertical rotary drum 011 on which a mandrel 015 is fixed. The mandrel 015 consists of but is not limited to sixteen stations 012, wherein each station 012 contains at least four holders 021 as illustrated in Fig. 2. Since the system 010 is designed to be operated offline for coating the elastomeric articles (relative to the glove dipping process), the finished gloves, which need to be internally coated, are loaded manually onto the holders 021 by operators 013. The system 010 also comprises a control panel 014 that receives the signal from the sensors on the holders 021 regarding the availability and status of the holders 021. The entire system 010 is controlled and navigated via the software installed in the control panel 014, which is constantly monitored and administered by the operators 013.

Referring to Fig. 3, the system 010 as illustrated therein is generally for coating the inner side of medical examination and surgical glove as a means of offline coating without inverting the gloves, in a cost and labor-saving approach. In the present invention, the gloves are loaded manually by the operators onto holders 021 on the designated stations 012 of the mandrel 015. In future embodiments, operators' manual loading of gloves onto the holders 021 is replaced by automated robotic arms. Once the system 010 is started, the rotary drum Oil is on continuous move or rotate. The gloves loading action may be performed while the rotary drum 011 is rotating. The sensors installed in each holder 021 detect the presence of a loaded glove and transmit the signal to the control panel 014 on the availability and status of the holder 021. Once the status has been updated and reflected on the screen of the control panel 014, the operators 013 then provide instructions by activating the lock valve button on the control panel 014 to automatically seal the cuff area of the glove on the holder 021. The air pressure sensors on the holders 021 receive the input signal from the control panel 014 and initiate the sealing process of the glove onto the holder 021 by creating a vacuum around the mouth (opening) of the holder 021 via an air locking mechanism 022, where the cuff area of the glove is sucked up using a direct current motor or a pneumatic system.

Once the glove has been sealed onto the holder 021, a signal is transmitted to the control panel 014, and an indicator is shown upon the complete seal of the glove onto the holder 021. After that, the rotary drum 011 is on continuous move and the blow valve button on the control panel 014 is activated to activate an air blowing mechanism 023. Then, the air valve is opened automatically to initiate airflow from the air tank or cylinder into the glove via the air blowing mechanism 023. The airflow rate into the glove is regulated by an air regulator fixed at the outlet of the air tank or cylinder. The air fills the glove until it reaches a pre-determined size, preferably 50-150% of its original size. Alternatively, the gloves can also be inflated with the incoming air to 0-50% or 150-200% of its original size. The inflation size of the glove can be precisely fixed by controlling the amount of air permitted to inflate the glove each time via the control panel 014. The inflation size of the glove is chosen depending on the dimensions of the glove and the type, physical and chemical properties of the coating material.

Once the air fills the glove to a pre-determined size, the air pressure sensor on the holder 021 transmits a signal to the control panel 014 to automatically switch off the blow valve button. Once the blow valve button has been switched off, the rotary drum Oil is on continuous move and a coating mechanism 024 is activated.

Once the coating mechanism 024 is activated, an indicator blinks to demonstrate the readiness of the gloves to be coated. At this stage, the inner side of the glove can be coated with the coating material in the tank, either in liquid or mist form via the coating mechanism 024. If the liquid form of coating has been designated, then the coating solution valve and the blow valve are activated together. In this case, only a pre-determined amount of the coating material solution from the coating material tank flows to the glove via the spray nozzle to coat the glove's inner side. If the misty form of coating has been designated, then the coating solution valve and the spray valve are activated together along with the blow valve. In this case, a pre-determined amount of the coating material solution from the coating material tank and a pre-determined amount of air from the air cylinder flow together to the glove via the spray nozzle to coat the inner side of the glove.

In either case, both coating options are expected to result in a controlled, targeted wet coating. The targeted wet coating can be controlled in three distinct ranges, which are small, medium, and large. The small targeted wet coating is expected in the range of 0.20 - 1.00 grams on the inner side of the glove. While the medium targeted wet coating is expected in the range of 1.00 - 1.50 grams, the large targeted wet coating is expected in the range of 1.50 - 2.00 grams on the inner side of the glove. The system 010 can precisely control the specific targets or range of wet coating via the control panel 014. The specific targets are also dependent on the dimensions of the glove and the type, physical and chemical properties of the coating material.

Once the desired wet coating has been achieved, the moisture sensor on the holder 021 transmits a signal to the control panel 014 to automatically switch off the coating solution valve and spray valve, depending on the initial designation. Then, the rotary drum Oil is on continuous move and an ejection mechanism 025 is activated. At this stage, the blow valve is then activated to initiate the air inside the glove to be blown out. The air blown out of the glove is circulated back into the air tank or cylinder, wherein the air pressure inside the air pipeline is regulated via the air regulators fixed at the inlet of the air tank or cylinder. Once all the air inside the glove is completely blown out, the air pressure sensor on the holder 021 transmits a signal to the control panel 014. The control panel 014 then provides an output signal to the holder 021 to release the seal on the opening (mouth) of the holder 021, thus loosening the glove's grip on the holder 021. The loosened glove is then ejected from the holder 021 into a collecting tray, bucket, or conveyor to be tumble dried.

In another embodiment, once the glove has been wet coated, the rotary drum 011 is on continuous move and the ejection mechanism 025 is activated, where the blow valve is activated to remove air from the gloves. Once all the air inside the glove is completely blown out, the air pressure sensor on the holder 021 transmits a signal to the control panel 014. The control panel 014 then activates an in-situ drying mechanism (not shown) and initiates the opening of a hot air valve. In this case, upon the activation of the valve, a stream of a predetermined amount of hot air enters into the glove. The hot air is generated by heating the air from the air pipeline via a heating element installation. Preferably, the hot air dwells inside the glove for 20-30s to facilitate in-situ drying of the inner coating material. Alternatively, the in-situ drying time can be varied to be less than 20s or in the range of 30-60s. The dwell time of the hot air inside the glove varies depending on the dimensions of the glove and the type, volume, physical and chemical properties of the coating material. Once the inner coating of the glove has dried, the moisture sensor on the holder 021 detects absence of any glove surface wetness and transmits a signal to the control panel 014 to automatically switch off the hot air valve. At this stage, the hot air inside the glove is blown out. The hot air blown out of the glove is cooled down by passing through a cooling element installed in an alternative air pipeline, which is controlled by the hot air valve. The cooled air is then circulated back into the air cylinder, wherein the air pressure inside the direct air pipeline is regulated via the air regulators fixed at the inlet of the air cylinder.

Once all the air inside the glove is completely blown out, the air pressure sensor on the holder 021 transmits a signal to the control panel 014. The control panel 014 then provides an output signal to the holder 021 to release the seal on the opening (mouth) of the holder 021, thus loosening the glove's grip on the holder 021. The loosened glove is ejected into a collecting tray, bucket, or conveyor from the glove holder. Since the coating material on the inner side of the gloves has been dried in- situ by the machine, the gloves need not be tumble-dried before packing.

In another embodiment, the mandrel's coated and dried gloves are filled with air again to help detect pinholes via an in-situ pinhole detection mechanism (not shown). At this stage, the air valve is opened automatically to initiate airflow from the air tank or cylinder into the glove. The airflow rate into the glove is regulated by an air regulator fixed at the outlet of the air cylinder. The air fills the glove until it reaches a pre-determined size, preferably 50-150% of its original size. Alternatively, the gloves can also be inflated with the incoming air to 0- 50% or 150-200% of its original size. The inflation size of the glove can be precisely fixed by controlling the amount of air permitted to inflate the glove each time via the control panel 014. The inflation size of the glove is chosen depending on the dimensions of the glove and the type, physical and chemical properties of the coating material. Once the air fills the glove to a pre-determined size, the air pressure sensor on the holder 021 transmits a signal to the control panel 014 to automatically switch off the blow valve button.

Then, the control panel 014 transmits a signal to the holders 021 to activate an in-situ visual defect inspection mechanism (not shown) and automatically switches on the LED light fixed on the exterior channel of the air blow nozzle to detect any defects which include but is not limited to glove thinning, discoloration, oil stains, white and black spots, and the presence of particles such as dust and hair. Once the LED lights are switched on, the gloves are visually inspected for defects. The duration of visual inspection can be precisely controlled from the control panel 014, wherein the LED lights can be set to be turned on for 10-20s to aid the visual inspection of gloves. Alternatively, the visual inspection time can be varied to be less than 10s or in the range of 20-30s. The LED lights are automatically turned off once the set time for visual inspection is up.

If no pinhole and/or defect is detected, then the air inside the glove is completely blown out, the air pressure sensor on the holder 021 transmits a signal to the control panel 014. The control panel 014 then provides an output signal to the holder 021 to release the seal on the opening (mouth) of the holder 021, thus loosening the glove's grip on the holder 021. The loosened glove is ejected into a collecting tray, bucket, or conveyor from the glove holder 021. In this case, the coated, dried, and pinhole and/or defect detected gloves need not be tumble-dried before packing.

If a pinhole and/or defect is detected in any glove, the air pressure sensor on the respective holder 021 signals the control panel 014 and prompts for preliminary auto-ejection of the gloves with pinholes and/or defects. Then, the air inside the respective glove is completely blown out, and the control panel 014 provides an output signal to the holder 021 to release the seal on the opening (mouth) of the respective holder 021. These defective gloves are then loosened from the holder 021 and ejected separately into a particular bucket that collects gloves with pinholes and/or defects.

The present invention is advantageous over the prior art, as it shows a significant reduction in processing steps and time involved in the offline coating process. The overall time required to automatically coat the inner side of the glove, starting from the loading of gloves on the mandrel 015 to automatic inflation and coating process up to the ejection from the glove holder 021, only takes about 60s. Alternatively, this basic process can take less than 60s or more than 60s, depending on the dimensions of the glove and the type, physical and chemical properties of the coating material.

In another embodiment, the basic process can be upgraded to include an in- situ drying using the in-situ drying mechanism (not shown), making the overall process time 90s. Alternatively, this upgraded processing time can be in the range of 60-90s or 90- 120s, depending on the dimensions of the glove and the type, physical and chemical properties of the coating material.

In another embodiment, the process can be further upgraded to include an in-situ pinhole and/or defects detection and inspection using the in-situ pinhole detection mechanism (not shown) and the in- situ visual defect inspection mechanism (not shown), making the overall process time 140s. Alternatively, the upgraded processing time, including the final glove ejection, can be in the range of 120-140s or 140-150s, depending on the dimensions of the glove and the type, physical and chemical properties of the coating material.

One skilled in the art will readily appreciate that the invention is well adapted to carry out the objects and obtain the ends and advantages mentioned and those inherent therein. The embodiments described herein are not intended as limitations on the scope of the invention.