The present invention relates generally to the field of paint spray devices, and more particularly to a new arrangement for retaining a splash plate or deflector in a rotary bell cup.
The number of painting and coating devices are known and have been developed for a range of applications. These include devices that feed paint or other fluid coating materials through a base unit towards an atomizing bell cup. The bell cup is an assembly that is attached to a hollow shaft that rotates in the front of the base. The base is commonly referred to as an atomizer, and often includes an air-driven turbine that may spin at high speeds, typically from 30,000 to 70,000 RPM and above. During operation, the coating material is advanced through the atomizer and into the bell cup assembly. The coating contacts a splash plate or deflector that causes the fluid to be dispersed along the inner surface of the rotating bell cup. Various forms of bell cups are known and are presently in use, often fashioned for different types of paints, coatings, and so forth. The fluid exits an annular area between the splash plate and the bell cup inner surface and flows along the bell cup to an edge from which it is propelled. The bell cup assembly may be charged, or electrodes around the atomizer may charge the paint or coating material to cause it to flow under the influence of static charge towards an in oppositely charged workpiece.
Although the particular form of bell cups used in such devices varies, it is typical to provide a splash plate assembly that is fitted into an aperture formed in the base of the bell cup. This assembly is often inserted into the aperture and retained in the aperture by a retaining ring arrangement. A typical conventional arrangement of this type is illustrated in
In this arrangement, as the pins P are pressed into openings in the splash plate and insert provided for this purpose, the openings tend to deform the radially inner surface or floor of the groove G. When this occurs, the groove may require remachining to remove the deformity. Moreover, the retaining ring R inserted into this groove extends radially, and given the deformation, may extend radially too far out of the groove in the areas of such deformity. The retaining ring may be damaged or sheered off during pressing of the splash plate assembly into the bell cup. This may result in the splash plate assembly not being sufficiently robustly assembled into the bell cup to withstand the forces to which the bell cup is exposed in use.
There is a need, therefore, for improved rotary bell cup and splash plate assembly designs. In particular, there is a need for an arrangement that can avoid the problems associated with retaining rings conventionally used in designs of the type discussed above.
The present invention provides a novel splash plate and bell cup design that addresses such needs. In particular, the invention offers a rotary bell cup assembly for atomizing paint or a flowable coating, comprising a bell cup and a splash plate assembly. The bell cup has an internal pathway for channeling paint towards an outlet. The splash plate assembly comprises a splash plate disposed in front of the outlet and an insert to which the splash plate is secured, the insert comprising a barbed section configured to enter into snapping engagement with an inner surface of the bell cup to secure the splash plate assembly in the bell cup.
The invention also provides a rotary bell cup assembly for atomizing paint or a flowable coating, that comprises a bell cup having an internal pathway for channeling fluid towards an outlet, and a splash plate assembly comprising a splash plate disposed in front of the outlet and an insert to which the splash plate is secured, the insert comprising a single piece having integral means for interfacing with an inner surface of the bell cup to secure the splash plate assembly in the bell cup.
The invention also provides a splash plate assembly for a rotary bell cup assembly for atomizing paint or a flowable coating, that comprises a splash plate configured to be disposed in front of an outlet of a bell cup, and an insert to which the splash plate is secured, the insert the insert comprising a barbed section configured to enter into snapping engagement with an inner surface of the bell cup to secure the splash plate assembly in the bell cup.
These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
The particular arrangement of the bell cup and bell cup body shown in
In the illustrated embodiment, the body of the bell cup includes a splash plate interface portion 26 that has features designed to receive and hold the splash plate assembly in place. These will be described in greater detail below. Moreover, upstream of the splash plate interface portion 26 is an annular opening 28 that receives the splash plate assembly and through which paint or any coating applied by the bell cup flows. As described in greater detail below, the splash plate interface portion 26 has an inner surface 30 on which features are formed that assist in retaining the splash plate assembly and that also may facilitate its extraction from the bell cup for servicing and replacement.
The splash plate assembly 14 essentially includes a splash plate 32 and an insert 34 to which the splash plate is secured. The splash plate is a generally planar structure extending from the center line 24 towards the inner walls of the bell cup and defining an annular opening therebetween through which paint or coating material will flow during operation. The shape of the surfaces of the splash plate may be selected to provide various flow characteristics. For example, flow-directing surfaces on the upstream side of the splash plate may be formed to more smoothly direct the flow of paint or coating material towards the outer edge as in the illustrated embodiment, although certain splash plates or deflectors may not include such features. Similarly, the shape of the outer peripheral side of the splash plate may be parallel to the bell cup inner surface, or the two may form a converging or diverging angle, depending upon how the assembly is intended to meter and distribute flow.
The splash plate is secured to the insert 34 by a series of pins 36. A suitable number of such pins may be provided, and in a presently contemplated embodiment three such pins are positioned at radially symmetrical locations in the assembly. Each pin in the illustrated embodiment includes a center portion that defines a desired distance between the splash plate and the insert, acting as a standoff at this location. The pins, therefore, appropriately position a rear surface 38 of the splash plate with respect to a front surface of the insert. The insert includes an internal pathway 40 that is in fluid communication with the space between the insert and the rear surface 38 of the splash plate. Recesses 42 are provided in the splash plate to receive an extension of pins 36, with similar recesses 44 being formed in the insert.
The splash plate and insert may be made of any suitable material, such as filled or un-filled acetal resin. The pins, on the other hand, may be made of a more rigid material, such as stainless steel. In the embodiment illustrated, the pins are barbed to prevent them from being easily removed from the splash plate and insert.
The insert, on a side opposite the splash plate, has an annular extension 46 that extends into and it is received by the opening 28 formed in the bell cup. The extension is surrounded, at least partially, by a skirt 48 that can be elastically deformed during insertion and removal of the insert, and splash plate assembly generally. An annular space 50 separates the skirt 48 from the extension 46 of the insert to permit inward deflection of the skirt 48 during its elastic deformation.
These features are illustrated in greater detail in
In the illustrated embodiment, the assembly also includes features that assist in removing the insert and splash plate assembly from the bell cup for servicing and replacement. In particular, as best illustrated in
In a presently contemplated embodiment, the skirt is slotted to facilitate its elastic deformation. This is best illustrated in
The resulting structure is susceptible to conventional manufacturing techniques (e.g., molding and/or machining), while providing a robust structure that securely holds the splash plate assembly in place during use. As noted above, the arrangement can be adapted to various bell cup and splash plate designs and configurations, while still avoiding problems with conventional designs, particularly those that rely on retaining rings and similar structures for retention. Moreover, the design may be retrofitted to many existing bell cups without alteration of the bell cups, particularly those that include shoulders or similar internal features with which the integral barbed features of the splash plate assembly may interface to exert a holding force.
While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.
This application is a Nonprovisional U.S. Patent Application of U.S. Provisional Patent Application No. 61/043,570, entitled “Splash Plate Retention Method and Apparatus”, filed Apr. 9, 2008, which is herein incorporated by reference.
Number | Date | Country | |
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61043570 | Apr 2008 | US |