Patent Application
20210078364
The present invention relates generally to protection of removable spindles, and more particularly, to such spindles used with axle assemblies for vehicles, including towed trailers, such as boat (marine) trailers.
In general, marine trailers often use wheels mounted on spindle axles. Arrangements such as the design shown in U.S. Pat. No. 6,299,259 can function well for that purpose. However, due to occasional overloading, component corrosion, debris impact, and/or wear and tear, it is desirable to be able to remove the spindle and repair or replace it, rather than replace the entire axle assembly. Unfortunately, since some spindle assemblies are exposed to salt water and other environmental factors, component corrosion can severely inhibit spindle replacement. In particular, the nut which secures the spindle to the torsion arm, and/or the threaded portion of the spindle to which that nut is attached, can be prone to such corrosion. Corrosion of those components directly inhibits spindle replacement.
Previously, it has been suggested to merely attach a cap to the spindle to protect against such corrosion. One example is shown in U.S. Patent Application Publication US 2018/0162163. However, that structure would require significantly greater expense (as, for example, from machining or casting of the torsion arm to form a cap slot or groove), can be limited in applications to where cotter pins are not applied as a nut lock, can fail to provide the versatility and reliability sufficient to justify the cost of product reconfiguration, and can adversely affect the structural integrity of the underlying components.
Also, it is desirable to have readily visible indicia of the level of corrosion developing on spindle axle assemblies or other component degradation events, so as to facilitate timely maintenance and/or component replacement. Over-arching cap structures can actually inhibit use of such indicia, as well as inhibit ready joint inspection by the user. An improved device is needed.
Further, it is desirable to allow spindle axle protection covers to be easily retrofitted into existing spindle axle assemblies, and without having to remove the spindle axle assembly components from the trailer in order to install. Preferably, whatever protection device is needed would be merely a direct, add-on component, having a significantly lower cost than the components it is designed to protect.
The present invention is a cap for covering and protecting the threaded end of a removable spindle. The cap has a cover with thread engaging tabs extending from a reservoir basin for dispensing corrosion inhibiting and/or lubricating material onto the spindle. The tabs include surface projections for retaining the cap to the spindle threads. The tabs are formed to fit within available slots of a slotted hex nut connected to the spindle (for retaining the spindle to a support structure). The cap further includes a flexible skirt or guard to make flexible surface contact with the torsion arm or spindle supporting structure. The skirt may include a sacrificial anode region to provide cathodic protection for the spindle threads and spindle retention nut, and/or visual indicia for recommended spindle maintenance or inspection. The skirt may be removable from the cap so that the cap could be reused with a new skirt. The cover portion of the cap can include integrally formed or topically applied visual indicia to indicate when recommended spindle maintenance or inspection is needed, according to the degradation of that indicia over time or exposure to adverse usage environments. The cap is formed to be used with existing spindle assemblies and to be reusable.
Other objects, advantages, and novel features of the present invention will become readily apparent from the following drawings and detailed description of certain preferred and alternative embodiments.
Accordingly, a primary objective of the present invention is to provide an improved cap for spindle axle assemblies, particularly where the spindle is removable from a vehicle. These improvements include providing apparatus for retaining a nut cap to a removable spindle which is inexpensive to manufacture, use, and maintain. Other objectives include: facilitate visual inspection of the spindle assembly, minimize component weight, allow reuse, reliably retain the nut to the spindle against various forces acting upon the nut and spindle during use, is retrofittable with existing spindle axle assemblies, include active corrosion inhibitors, and is reliable in vehicular and marine trailer applications.
The cap 21 has two distinct portions, a cover 20 and a guard or skirt 22, which can be integrally formed as a single element, or separately formed from multiple pieces so as to optimize components and costs, and permit reusability of the cover 20. The cover has an end wall portion 32 that extends to a perimeter wall portion 34 to form a bowl or cup shape. The spindle retainer portion is mounted within and to the underside of cover 20, including, for example, a plurality of spaced apart tabs 24 for engaging the exterior surface of spindle 10, preferably in the threaded end region 14, with four such tabs being shown in
The skirt 22 includes a peripheral region 30 which faces the surface 46 of torsion arm 12 when the cap 21 is fully mounted onto the spindle assembly. The surface 46 is commonly not machined and/or does not have any controls as to the surface finish requirements. In some embodiments, the swing arm 12 is a cast component that has a rough surface. In other embodiments, the swing arm 12 may be a welded assembly with a weld joint, weld splatter, or rough-cut surfaces. The peripheral region 30 is designed to seal to that uncontrolled surface. In the event that the surface 46 is machined or otherwise controlled, the skirt 22 will also seal. That peripheral region 30, as shown, is shaped like a lip seal that is formed from flexible and resilient material, so that it can conform to the surface topography of the torsion arm about the area where the spindle is received and allow the cap 21 to prevent or reduce debris and corrosive fluid from contact with the surface of spindle 10 and retaining nut 16. To retain the skirt 22 to the cover 20, it has a pocket 38 that receives the perimeter wall portion 34. It may be advantageous to form skirt 22 entirely from such material, and in other embodiments it may be sufficient to form only the portions of skirt 22 furthest from top surface 26 (or closest to torsion arm 12) from such material. The amount of flexibility and resiliency of this material can be readily selected depending upon the degree of variation in surface topography or roughness of the torsion arm finish. The skirt 22 can allow the cap 21 to effectively seal against existing torsion arms (and similar supports for spindles) without the need for specially formed grooves or slots in the torsion arm 12. This can aid in retrofitting the cap 21 to removable spindle assemblies in the field. As installed, the cap 21 and the swing arm 12 form an enclosed chamber 50, shown in
As shown, the skirt 22 can be connected to cover 20 via a close interference fit between the pocket 38 and perimeter wall portion 34, especially in certain applications where the environment will not result in adverse dimensional change of those elements (such as may be caused by wide temperature variations and/or excessive vibration with certain plastic or metal components). Alternatively, skirt 22 and cover 20 can be joined by friction or ultrasonic welding, or by adhesives. Further, there are certain applications of the present invention where it is desirable for skirt 22 and cover 20 to be removably connected, such as by a frangible connection in either one piece or two piece constructions, or by twisting off the interference fit in a two piece construction. Such separability can allow either cover 20 and/or skirt 22 to be reused in connection with caps for spindle assemblies.
Given the salt water environment for some applications of the cap 21, it can be advantageous to include cathodic protection features. For example, in order to limit the corrosive effects of the environment upon threaded end region 14, nut 16, cotter pin hole 17 and/or cotter pin 18, skirt 22 can be formed from a sacrificial metal which acts as a sacrificial anode. When present, the corrosion caused by the environment would occur earlier and/or more extensively at the guard/torsion arm interface, than at the internal components. Alternatively, the sacrificial metal or another anode suitable material can be applied as a surface treatment to skirt 22 over its entire surface or over a portion thereof, such as at the peripheral region closest to the torsion arm 12. One example of this would be to apply an aluminum film layer over a plastic molded skirt 22. In applications where the cap 21 is to be reused, at least in part, a skirt 22 which is “spent” by such cathodic protection can be replaced with a new skirt 22 mounted or attached onto cover 20. Alternatively, a spent skirt 22 can be cleaned and retreated with a surface anode, particularly where the anode was applied initially by a surface coating.
Further, cathodic protection can be extended into other components used with the cap 21. For example, the relative dimensions of washer 15 and skirt 22 are established so that when the cap is fully mounted onto the spindle axle assembly, the peripheral region of skirt 22 adjacent torsion arm 12 is also in close proximity to (or in contact with) the circumferential edge of washer 15. In those applications, it can be advantageous for washer 15, at least in a region close to its circumferential edge, to have a sacrificial anode as well, such as by a surface coating or metallic composition of the washer itself. This can provide additional protection to the threaded interface between spindle 10 and nut 16, which facilitates ease of removal of spindle 10 from torsion arm 12 whenever removal is desired by the user. Alternatively, an anode sheet or film can be applied adjacent the washer for this purpose. Further, where the sacrificial anode of skirt 22 and washer 15 are in close proximity, the corrosion “growth” on the anode can merge together from those elements and create more of a mechanical barrier between the environmental fluids and threaded end region 14. In effect, this can reduce the effect of corrosive salt water coming into contact with the spindle threads in certain applications of the present invention.
It may be advantageous to have at least a portion of skirt 22 which includes a sacrificial anode be readily visible to users on exterior of the cap. In this way, visible indicia of the extent of corrosion can be easily seen without removing the cap until needed. If sufficient corrosion is then seen, the cap can be replaced and/or serviced (along with the spindle assembly as needed) in a timely manner. The visual indication of the need for removal can be facilitated, for example, by selecting the anode material to change color or incur significant deformation when the desired level of corrosion has occurred to denote servicing of the cap and/or spindle assembly.
Alternatively (or additionally), cover 20 can be formed with or have applied to its surface, visual indicia of significant corrosion and/or the passage of time, by the selection of materials in its composition or by having a label adhesively mounted to end or top surface 26. Such a label can be formed from a similar anodic material as is used for cathodic protection with skirt 22. Alternatively (or additionally), the label include a visual marker which changes color distinctively in response to a predetermined passage of time and/or immersion in the usage environment. That change can be a signal to the user that replacement and/or servicing of the cap is needed to refill the corrosion inhibiting or lubrication material disposed in reservoir 28. Further, in applications of the present invention where the cover 20 is not intended to be reused, the visual indicia to indicate time for such servicing can be incorporated into the cover structure itself, and a new cover would be used after the servicing. Top surface 26 can also serve to contain or support a brand or part identifier, so as to ensure the user of genuine servicing standards for the spindle assembly.
In order to secure the cap to the spindle assembly and fully seat skirt 22 against torsion arm 12, the user aligns the tabs 24 with the unused slots 44 and then applies force to push the cap 21 towards the spindle 10. Each tab 24 has chamfer surfaces 40, 42 that help to guide the tabs 24 into the slots 44 of the nut 16. If aligned properly, the plurality of tabs 24 will temporarily flex apart upon receiving threaded end region 14, and then grip the spindle threads and resist unintended removal of the cap from the spindle threads. Because the tabs 24 reside in the slots 44, the cover 20 cannot loosen by unscrewing. The cover 20 is dimensioned to accommodate whichever form of cotter pin is desired for a particular spindle assembly. The remaining four slots 44 in nut 16 are used by tabs 24, which enter those slots 44 and grip the exposed portions of threaded end region 14. The number and size of protrusions 29 associated with teach tab 24 can be selected as appropriate to the nature of the threading of spindle 10 within threaded end region 14.
In other embodiments, tabs 24 can be greater in number or dimensionally extended and/or merged together as needed for full threading contact about the circumference of threaded end region 14. This would be appropriate, for example, if the cap 21 is to be secured to spindle above the nut 16. Alternatively, cover 20 can be formed with a conventional “push nut” type of element rather than tabs 24, for use in removably retaining the cap to the spindle.
Although the present invention has been shown and described herein with respect to certain preferred embodiments and alternative configurations, those were by way of illustration and example only. For example, tabs 24 can be formed with ferrule inner surfaces in place of protrusions 29, thereby preventing reuse and requiring a new cover 20. This arrangement can be useful as indicia of unauthorized spindle servicing.
It is understood that while certain aspects of the disclosed subject matter have been shown and described, the disclosed subject matter is not limited thereto and encompasses various other embodiments and aspects. No specific limitation with respect to the specific embodiments disclosed herein is intended or should be inferred. Modifications may be made to the disclosed subject matter as set forth in the following claims.
