Patent Application
20080069489
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:
In accordance with exemplary embodiments disclosed herein, an injection moldable end cover assembly is provided. The arrangement may be adapted to fit a range of bearing housing styles, including standard pillow blocks, tapped base pillow blocks, two-bolt flanges, four-bolt flanges, flange brackets, piloted flanges, wide-slot take-up bearings, and top angle take-up bearings. As will be discussed in greater detail below, the end cover assembly may also fit bearing housings having a variety of sizes and dimensions without external machining of the bearing housing. The end cover assembly functions as a robust guard and cannot be easily dislodged by incidental contact.
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The housing assembly 10 also includes an end cover 14 and an attachment clip 16. The end cover 14 may be inserted into a straight bore of the bearing housing 12, as described below. The attachment clip 16 is provided to secure the end cover 14 to the bearing housing 12. Specifically, the attachment clip 16 may be attached to the end cover 14 and secured to a grease fitting 18 of the bearing housing 12, or to any other fastener or structure on the housing with which the clip may interface and be mechanically supported.
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The end cover 14 and the attachment clip 16 are separate parts capable of forming a single rigid structure. Specifically, the attachment clip 16 can be coupled with the end cover 14 as shown in
In particular, in the illustrated embodiment, the end cover 14 has a toothed tab 28 protruding from the outer surface of the end cover 14. A reinforcement rib 30 is provided for the toothed tab 28 and as its name indicates, provides reinforcement for the toothed tab 28. The reinforcement rib 30 protrudes from the outer surface of the end cover 14 in a generally perpendicular orientation to the toothed tab 28. Additionally, in the illustrated embodiment, the end cover 14 has slots 32 every 90 degrees around the open end of the end cover 14. The slots 32 are provided to allow condensation to exit the end cover 14 when placed in operation.
The attachment clip 16 has alignment tabs 26 for securing the attachment clip to the end cover 14. When the attachment clip 16 and the end cover 14 are coupled together, the alignment tabs 26 surround the toothed tab 28 protruding from the end cover 14. Compressive forces applied by the alignment tabs 26 hold the attachment clip 16 in position relative to the end cover 14, and ultimately, when placed in service, hold the end cover in a desired position with respect to a point of attachment of the attachment clip to the bearing housing.
As mentioned above, the end cover assembly 22, including the end cover 14 and the attachment clip 16, may be manufactured through an injection molding process. Specifically, the end cover 14 and the attachment clip 16 may be made of any suitable material, such as engineering plastics. In a presently contemplated embodiment, these components are made of acetal resin. For example, the acetal resin may be one commercially available under the designation Delrin®, sold by DuPont Company, of Wilmington, Del. The injection molding process provides for an efficient means for producing the end cover 14 and the attachment clip 16, and provides both economic and structural advantages over other methods. Such other methods may, however, be employed for forming parts falling within the scope of the invention.
Another view of the end cover 14 is illustrated in
The toothed tab 28 is designed to engage an attachment clip 16, as mentioned above. Specifically, the toothed tab 28 has teeth 37 for engaging a surface of an attachment clip 16. Although various methods may be used to create the teeth 37, one process is generally referred to as a pull. The pull process can achieve characteristics of 0.015 inches or less. The pull process may create a bias, meaning that the teeth may have angled profiles relative to the toothed tab 28.
When attaching the end cover to a bearing housing 12, the open end of the end cover 14 may be inserted into a straight bore of the bearing housing. Such bores may be provided in many bearing housings, and consist of a geometry of the housing at which the central opening has a straight cylindrical shape. This location may be ideal for receiving and stabilizing the end cover. The diameter of the end cover can vary according to the diameter of the straight bore of the bearing housing being used. Additionally, the straight bore may have an interference fit (not shown) so that the end cover fits securely in the straight bore. Once the end cover is coupled to the bearing housing, the sidewall 34 and the back panel 36 preclude exposure to a shaft that rotates during operation.
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As described above, the teeth 37 of the toothed tab 28 may have a bias feature. Similarly, the teeth of the toothed wall 38 may have a bias. This bias may comprise an asymmetrical cross sectional geometry that results in a force for sliding the tab into the cover that is different from (e.g., less than) the force required to extract or slide the tab out of engagement with the cover. That is, the teeth 37 may be biased in an opposing direction relative to the bias of the toothed wall 38 when the attachment clip 16 and the end cover 14 are coupled together. Thus, the teeth may slide past each other in one direction and interlock to prevent movement in the opposite direction. Thus, the bias feature may help to prevent the end cover 14 and attachment clip 16 assembly from becoming separated from each other.
In addition to attaching to the end cover 14, the attachment clip 16 is configured to be secured to the bearing housing 12. Specifically, the attachment clip 16 may be attached to any suitable point on the bearing housing, such as to a grease fitting or other structure of the bearing housing 12. The attachment clip 16 has a securement tab 44 having a generally orthogonal orientation relative to the toothed wall 38 and the alignment tabs 26. The securement tab 44 may take several forms and secure to the bearing housing in different ways, as will be described below in conjunction with alternative embodiments.
The securement tab 44 of attachment clip 16 is configured to allow the attachment clip 16 to be pressed around a head of a grease fitting. Thus, the attachment clip 16 does not require the removal or loosening of a grease fitting in order for the attachment clip 16 to be secured to a bearing housing 12. Specifically, an aperture 46 is provided to fit over the head of the grease fitting. An interference fit between the inner diameter 48 of the aperture 46 and the head securely attach the attachment clip 16 to the bearing housing 12.
In accordance with an alternative exemplary embodiment, an attachment clip is illustrated in
In
The attachment clip 54 has a securement tab 44 with a section 56 configured to fit around a grease fitting of a bearing housing. Specifically, a fitting opening 58 is provided to allow the section 56 to secure to a grease fitting. Like the snap tabs 52 of the attachment clip 50, the section 56 secures the attachment clip 54 to the grease fitting. A recessed surface 60 may be provided on a top surface of the securement tab 44 to facilitate re-lubrication of a bearing housing.
In
The metallic washer 66 is illustrated as being a C-shaped washer so that the attachment clip 62 can be secured without entirely removing a grease fitting. The attachment clip 62 may simply attached by loosening the grease fitting and sliding the open ended securement tab 64 into place around the grease fitting. Once the securement tab 64 is in place the grease fitting may be tightened. Alternative embodiments (not shown) may have closed washers and the grease fitting may be removed in order to install a washer.
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Additionally, the attachment clip 16 is secured to the grease fitting 18. Various embodiments of the securement tab 44 have been described and provide different means for securing the attachment clip 16 to the bearing housing 12. The various embodiments may provide for varying heights of clearance between securement tab 44 and the bearing housing 12 to provide compatibility with various bearing housing sizes.
As discussed above, the end cover 14 and the attachment clip 16 provide a rigid structure when coupled together. The relative position of the end cover 14 and the attachment clip 16 can vary depending on the size of the bearing housing. As such, a single end cover and attachment clip 16 may be implemented for various sizes of bearing housings.
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.
