The present invention relates to a system and a method for automatically applying a bead of a sealant within a peripheral groove.
Although the present invention is of general application, it was initially developed with reference to assembling a lid on a container for a battery pack for powering an electric traction motor of an electric vehicle. In the assembled condition of the lid on the container, these elements define between them, along the lateral surface of the container, a peripheral groove, which must be filled with a bead of a sealing agent, having the function of both rigidly connecting the lid to the container and of sealing the inside of the container from the outside.
A usual technique in applications of this type is to apply a bead of sealant along a peripheral edge of the container, before the lid is applied to the container. By operating in this way, it is also possible to deposit an excess quantity of sealant on the edge of the container, since the subsequent application of the lid on the container, with which the correct adhesion between the two elements is ensured, causes the leakage of any excess quantity of sealant. In the specific application mentioned above, however, there is a need to ensure that the bead of sealant is applied after the lid has been applied to the container. In this case, if the sealant is applied in an automated processing station, with the aid of a robot carrying a sealant dispensing head, it is necessary to measure the amount of sealant applied relatively precisely. However, the required amount of sealant cannot be predetermined, due to the inaccuracies in the geometry of the elements (in the example cited the container and the lid) defining the peripheral groove wherein the sealant is to be deposited. In the case, for example, of the specific application mentioned, the lid is made of plastic material, and the container of aluminum alloy, and they are made with manufacturing tolerances that are not particularly tight, so that, as indicated above, the profile of the lateral surfaces defining the peripheral groove varies continuously along the perimeter of the groove, and also varies between different specimens of the products advancing along the production line. Therefore, the size of the peripheral groove varies along the perimeter of the groove and varies from product to product.
There is, therefore, a need for a system and a method that allow the application of the bead of sealant to be carried out in a completely automated and rapid way, and that nevertheless guarantee the application of the correct quantity of sealant in the various portions of the peripheral groove along the perimeter of the peripheral groove, despite the variability of the dimensions of the groove, both along the perimeter of the same product, and from product to product along the production line.
The object of the present invention is, therefore, to produce a system and a method for automatically applying a bead of sealant within a peripheral groove defined between two elements coupled to each other and having dimensions that are not strictly predetermined, which are able to resolve the problems outlined above.
In particular, one object of the invention is to produce a system and a method for automatically applying a bead of sealant that allows the sealant to be applied automatically and in a short time and that, nevertheless, guarantees the dispensing of the correct quantity of sealant within each portion of the peripheral groove along its perimeter.
An additional object of the invention is to produce a system and a method of the type specified above that are able to achieve the aforesaid objective by simple, low-cost means.
An additional object of the invention is to produce a system and a method for applying a bead of sealant in a peripheral groove defined between two elements coupled together, which makes use of a sealant dispensing head equipped with a dispensing nozzle mounted in a displaceable manner, made of plastic material, and having a geometry that is not rigorously predetermined, nevertheless ensuring precise control of the position of the dispensing end of the dispensing nozzle, with simple and low-cost means.
One or more of the aforesaid objects is achieved, according to the invention, by providing a system for automatically applying a bead of a sealant within a peripheral groove, which is defined between two elements coupled to each other and having dimensions that are not strictly predetermined, so that the peripheral groove has two facing lateral surfaces whose profile is continuously variable along the perimeter of the peripheral groove, said system comprising:
In a preferred embodiment, the aforesaid pump is configured to activate a constant and predetermined delivery flow rate of the sealant and that the electronic controller is configured to dynamically vary the speed of movement of the dispensing nozzle during the second pass, so as to apply the calculated amount of sealant in each portion of the peripheral groove along the perimeter of the peripheral groove.
According to an additional characteristic, the system of the invention also comprises:
In the preferred embodiment, the aforesaid dispensing nozzle is constituted by an element of plastic material mounted in a replaceable manner, the geometry of which is not rigorously predetermined. The sealant dispensing head carries a reference element, having a predetermined geometry (for example, a steel stylus), adjacent to the dispensing nozzle, and having a position with respect to the manipulator robot that is known by said electronic controller. The system also comprises a vision system configured to detect the relative position of a dispensing end of the dispensing nozzle with respect to the aforesaid element, and to send data indicative of said relative position to the electronic controller.
According to another preferred characteristic, the aforesaid one or more sealant tanks are carried by the robot and are of a refillable and/or replaceable type, so that the movements of the robot are not hindered by pipes for connection to a sealant tank placed on the ground.
The invention also relates to the sealant application method implemented by means of the system described above.
Further characteristics and advantages of the present invention will become apparent from the description that follows with reference to the attached drawings, provided by way of non-limiting example, wherein:
The present invention relates to a system and a method for automatically applying a bead of a sealant within a peripheral groove, which is defined between two elements coupled to each other and which has dimensions that are not strictly predetermined, so that the peripheral groove has two facing lateral surfaces whose profile is continuously variable along the perimeter of the peripheral groove.
In the present description, the term “sealant” is used to indicate both the case of a fluid having only sealing properties, and the case of a fluid having sealing properties and also adhesive properties and, in general, the case of any adhesive fluid.
In
As can be seen in particular in
Preferably, the aforesaid vertically-movable support members and the aforesaid auxiliary centering members are driven by servo-controlled electric motors, in such a way that an electronic controller E of the processing station (schematically illustrated in
Applying the bead of sealant into the peripheral groove 4 of the container 1 is carried out by means of a robot manipulator R.
In the illustrated example, the manipulator robot R is a multi-axis robot, comprising a series of mutually articulated robot elements, ending with an attachment flange 11 to which a sealant dispensing head 12 is rigidly connected.
In the example illustrated in
With particular reference to
Thanks to this arrangement, the manipulator robot R is able to move the sealant dispensing head 12 around the container 1 without this movement being hindered by a pipe connecting the dispensing head with a sealant tank arranged stationary on the ground.
Again with reference to
As can be seen in
With reference again to
The profilometer 29 is of any known type configured to optically detect the profile of a surface illuminated thereby, thus operating without contact.
With reference also to
As schematically illustrated in
The manipulator robot R moves the sealant dispensing head 12 by carrying out, as indicated, a first pass along the peripheral groove 4 of the container 1 without dispensing sealant, but only for the object of bringing the profilometer 29 to detect the entire perimeter extension of the groove 4.
This operation is made necessary due to the fact that the elements of plastic material constituting the container 1 have a geometry that is not strictly predetermined, so that the profile of the lateral surfaces 5, 6 that delimit the groove 4 varies in an unpredictable way along the perimeter extension of the groove of the same container 1, and from one container to another in a production in series of such containers.
On the basis of the data detected by the profilometer 29, the electronic controller E is, therefore, able to calculate the correct amount of sealant to be applied in each portion/section of the peripheral groove 4 along the perimeter extension of the peripheral groove 4.
Once these operations have been carried out, the robot R moves the sealant dispensing head 12 by making a second pass along the peripheral groove 4, this time to apply the bead of sealant.
In the case of the specific example illustrated, the sealant dispensing pump(s) 40 supplies a constant flow of sealant. Therefore, the quantity of the sealant is metered by the electronic controller E by varying the speed of movement of the dispensing nozzle 14 (
Of course, it would also be possible to control the amount of sealant applied to each portion of the peripheral groove by setting a variation in the flow rate of the sealant delivered by the nozzle. This solution is difficult to implement in the case of a two-component sealant, as the two components fed by the respective pumps 40 mix in a mixer before reaching the nozzle, which makes it difficult to control the flow rate delivered by the nozzle. However, in the case of application of a single-component sealant, it is possible to set up a variable flow pump and control a variation in the flow rate delivered by the nozzle 14 based on the detection using a profilometer 29. In this case, the invention may envisage that the optical detection of the size of the peripheral groove and the application of a variable flow rate of sealant along the perimeter of the peripheral groove are performed in a single pass of the dispensing head.
A further problem that arises with sealant dispensing heads 12 of the type indicated above resides in the fact that the dispensing nozzle 14 tends to become clogged and obstructed, for example, when the sealant dries up during processing breaks. To solve this problem, the nozzle 14 is preferably made of plastic material (in order to be of reduced cost) and is connected in a replaceable manner to the connector 17. However, this expedient gives rise to the further problem due to the fact that the geometry of the nozzle 14 made of plastic material is not rigorously predetermined, since the nozzle made of plastic material is subject to dimensional variations both as a result of manufacturing tolerances that are not particularly narrow, and due to deformations. To overcome this drawback, the sealant dispensing head 12 of the system according to the invention is equipped with a reference element, which in the illustrated example consists of a steel stylus 30 having a rigorously predetermined geometry, projecting parallel to and adjacent to the dispensing nozzle 14 (see in particular
Before the second pass for dispensing the sealant in the peripheral groove 4, the robot R places the dispensing nozzle 14 in front of a stationary station on which a vision system device 31 is arranged (area B) of
In the case of the example, as indicated above, the steel stylus 30 is arranged parallel and adjacent to the dispensing nozzle 14 and has a tip 30A whose position with respect to the robot R is known to the electronic controller E. After a replacement of the dispensing nozzle 14, the robot R carries the two tips 16, 30A of the nozzle 14 and of the steel stylus 30, respectively, in front of the vision system 31, which detects the relative position of the tip 16 of the dispensing nozzle 14 with respect to the tip 30A of the steel stylus 30. The data relating to the aforesaid relative position are sent to the electronic controller E, which can consequently control the robot R, taking into account the actual position of the dispensing tip 16 of the dispensing nozzle 14. The unique characteristic of this measurement method is that of being able to eliminate the positioning error of the nozzle with respect to the vision system when resetting the position of the nozzle 14, as the system measures the position of the nozzle 14 with respect to the stylus 30, thus providing data free from any robot positioning errors during this measurement.
Again with reference to
In the case of the example, the refilling station, indicated in its entirety by 50, comprises two extrusion pumping units 51, of any known type (and, therefore, not described in detail here), which feed respective fluid components into two supply pipes 52 connected to an apparatus 53 interfacing with the dispensing head 12.
With reference to
A control panel 56 and a container 57 for collecting purges of sealant are arranged adjacent to the coupling device 55.
Of course, without prejudice to the principle of the invention, the details of construction and the embodiments may vary widely with respect to those described purely by way of example, without departing from the scope of the present invention, as defined by the attached claims.
Number | Date | Country | Kind |
---|---|---|---|
102021000008159 | Apr 2021 | IT | national |
This application is filed pursuant to 35 U.S.C. § 371 claiming priority benefit to PCT/IB2022/052873 filed Mar. 29, 2022, which claims priority benefit to Italian Patent Application No. 102021000008159 filed Apr. 1, 2021, the contents of both applications are incorporated herein by reference in the entirety for all purposes.
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/IB2022/052873 | 3/29/2022 | WO |