Patent Publication Number: US-2020282521-A1

Title: Adjustable pivot bolt for a sealed manhole clamp

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application Ser. No. 62/919,379, filed on Mar. 7, 2019, the disclosure of which is incorporated herein by reference. 
    
    
     FIELD OF DISCLOSURE 
     This disclosure generally relates to a manhole cover, as applied to its weld ring or other supporting structure, for use upon a tank trailer or dry bulk trailer or other conveying vehicle, wherein the lever assemblies used to hold the manhole cover sealed in place, incorporate a pivot bolt, wherein its adjustability through the use of a threaded pivot bolt, where the threads are sealed internally of its structure, prevents exposure of its adjustment to any of the deleterious materials being conveyed, or inclement weather conditions, to assure that adjustability can be subsequently achieved, for each lever assembly, during its usage and application. 
     BACKGROUND OF THE DISCLOSURE 
     Granular product, such as grain or corn, may be stored or shipped in bulk containers such as tank trailers, railroad tank cars, and pipelines for transportation from one site to be delivered to another. Such granular products may include farm produced grains, and many other dry bulk materials, such as cement, granular chemical products, and related type of conveyed materials, which during their processing, as is known, the dust and grime can easily cover substantially all of the various components that are used in their transit. Even with a manhole cover that seals upon the conveying vehicle, usually upon its weld ring, such are exposed to many of the residual materials being conveyed, during processing, and also, since their lever assemblies are provided upon the upper portion of such a manhole cover, or a plurality of them, these are also exposed to inclement weather conditions, throughout their usage. 
     Dry bulk trailers have manhole cover assemblies that allow access to the vessel, or trailer, for loading and inspection. The lids are held down with cam handles that compress a gasket to seal the vessel in its upper regions. In use, the manhole covers require periodic adjustment to compensate for the compression set and loss of resilience of the gasket material that seals the cover to its supporting structure. 
     Current state of the art cams, formed of the lever assemblies, are held in place with pivot bolts that have exposed threads that corrode as they are exposed to the elements, and also to the product that is spilled from the tank trailer, during its filling or unloading. Such corrosion causes the threads to cease to turn and makes further adjustment impossible, after a period of time. 
     As is well known in the art, where a manhole hardware is removed from the trailer, after an extended period of time of usage, the exposed threads, that normally would lead towards the adjustability of the hardware, seize in place, and will not allow any further adjustment to the lever assembly, for future usage. Hence, the only alternative in the art is simply to replace the entire assembly, in the form of the adjustment bolt, that will just not allow any further manipulation to adjust the amount of pressure that is applied by the lever assembly, upon its associated manhole cover, when sealing it upon its opening into the tank trailer or conveying vessel. 
     Examples of such prior art cam lever assemblies can be seen in the U.S. Pat. No. 6,595,716, to VanDeVyvere et al, which shows such an assembly. As is noted, it can be seen that the pivot bolt that holds the cam lever in position, has an exposed threaded bolt, that secures into a lower connector, which means that the exposure of these components to the atmosphere, weather conditions, and any of the granular material being conveyed or delivered into or discharged from its associated vehicle container, will be exposed to these conditions, and will eventually fail, if not corrode, after prolonged usage. 
     The U.S. Pat. No. 7,427,089, shows a similar type of apparatus provided for securing a hatch cover to the vessel of a railroad car, and wherein its cam shaft has an upper threaded securing member exposed to the elements, and the dust from the granular material being conveyed and processed, which does lead towards corrosion, and clogging, and an eliminating of the adjustability of the securing means, after prolonged usage. These are examples of the early types of adjustable connectors that have been used in the prior art, and which have led towards their eventual deterioration, and non-usage, because of the exposure of the adjustable aspects of the bolt, to the environment, leading towards their corrosion, which prevents any further adjustability in the sealing of its manhole and hatch covers onto the conveying vessel. 
     The present disclosure is designed to obviate and overcome many of the disadvantages and shortcomings as experienced with prior manhole covers. Moreover, the present disclosure is related to a manhole cover, and the ability to attain complete sealing onto its weld ring or related supporting structure, and which can sustain its adjustability, in its securement, and sealing onto the weld ring, even after very prolonged usage and application. 
     SUMMARY OF THE DISCLOSURE 
     The present disclosure is directed to a manhole cover device, which is secured by a series of lever assemblies onto its seal ring, or other structure, provided through the top portion of the tank trailer, dry bulk trailer, or other conveying vehicle, and more specifically, relates to the effective combination of structures forming the pivot bolt that secures with the handle or levers that clamp the cover or latch onto the tank trailer or railway car, during conveyance. More specifically, the sealed manhole clamp of the present disclosure relates to the formation of that pivot bolt, in a manner that conceals its adjustable threaded engagement of its various components together, so as to prevent access of the dry bulk material, dust, or even inclement weather in attaining access to the components threaded engagement, to prevent its corrosion, clogging, that maintains the possibility of attaining further adjustment to the lever assemblies, even after sustained usage. 
     A further feature of the sealed manhole clamp, and more specifically with respect to structure of its pivot bolt, that holds the lever assembly, and its manhole cover to the weld ring of the vessel, is that the threaded engagement between the components of the pivot bolt are sealed by means of an O-ring, to even further prevent the access of moisture to their threaded engagement, and which allows for sustained adjustability, after prolonged usage. In addition, and to prevent the entrance of any dust or other debris from attaining access to this threaded relationship, within the pivot bolt structure. In formation, and to attain the benefits of the sealed manhole clamp of the present disclosure, the bottom end of the upper cylindrical member for the bolt, which receives the threaded bolt extending upwardly through its bottom end, for threaded engagement upwardly therein, allows for adjustability in the length of the bolt, and that bottom has a scraper like configuration, which when the pivot bolt is adjusted, it scrapes away any dust or debris that may have accumulated thereat, so as to further prevent its entrance into the adjustment feature of the threaded engagement between the bolt components, even after sustained usage and application. 
     The present sealed manhole clamp provides a manhole cover device, held by lever assemblies onto the upper opening into the tank trailer, and the like, where the adjustable components that make up the pivot bolt are sealed from the elements, and thereby provide for adjustment over a more sustained and lengthy period of time, throughout the life of the assembled structure. 
     A further object of the present sealed manhole clamp is to provide means for sealing the threaded engagement of the various components that make up the pivot bolt for the lever assemblies, so as to prevent their corroding or deterioration even after prolonged usage. 
     A further object of the sealed manhole clamp is to provide means for sealing the operative components of the pivot bolt for a lever assembly holding a manhole cover onto its supporting structure at the top of a tank trailer, railway car, or the like. 
     Yet another object of the sealed manhole clamp is to provide means for sealing the adjustable components of the lever assembly of a manhole cover through the designed application of O-rings, scraper like elements, and related structures that prevent the entrance of inclement weather, dust, or other debris to the operating threads of the adjustable pivot bolt. 
     These and other objects may become more apparent to those skilled in the art upon review of the Summary of the Disclosure as provided herein, and upon undertaking a study of the Description of Its Preferred Embodiment, in view of the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In referring to the drawings: 
         FIG. 1  shows a standard manhole type cover applied onto its weld ring normally secured to the top of a tank trailer, or the like, and showing prior art pivot bolts as currently used in the industry; 
         FIG. 2  shows a side view of the adjustable pivot bolt constructed according to the present disclosure used in the manhole hardware; 
         FIG. 3  is a front view of the adjustable pivot bolt of this disclosure; 
         FIG. 4  is a sectional view of the pivot bolt taken along the line  4 - 4  of  FIG. 2 ; and 
         FIG. 5  is an enlarged view of a portion of the adjustable bolt of this disclosure, taken along the detailed line  5  of  FIG. 4 . 
     
    
    
     DESCRIPTION OF A PREFERRED EMBODIMENT 
     In referring to  FIG. 1 , therein is shown a manhole cover  10  that is secured by a number of lever cam assemblies  12 , and showing the prior art style of a number of pivot bolts  14  that secure the lever cam assemblies  12  and the cover onto a seal ring  16 , or other structure, provided atop a tank trailer or vessel  18  surrounding an opening  20  normally provided into such a vessel  18 . Such lever cam assemblies  12 , which include a number of camming surfaces  22 , are designed to bind upon a cover plate  24 , when a number of lever arms  26  associated with each of the lever cam assemblies  12  are pivoted into closure and into the position as noted in said  FIG. 1 . The pivot bolts  14  each have a bottom  28  which are secured by means of a pivot pin  30  to a number of corresponding mounts  32 , that are affixed to a side  34  of the seal ring  16 , as noted, and the pivot pin  30  can be removed, upon removal of a cotter pin  36 , as can be understood. Each of the lever cam assemblies  12  has an upper part  38  that further includes a second pivot pin  40 , that extends through a bifurcated end  42  of the lever arm  26 , and further through an upper part  44  of the pivot bolt  14 , as can be noted. 
     What is to be noted for the prior art style of pivot bolt  14 , as further noted in  FIG. 1 , is that the pivot bolt  14  threadedly engages into a cooperating lower sleeve like portion  46 , and as can be seen, and an upper end  48  of the sleeve  46 , has the lower portion  28  of the bolt  14  threaded downwardly into said sleeve  46 , which means that any dust, debris, or even inclement weather conditions, can permeate into a gap  50 , and attain access to any threaded engagement provided therein, that normally leads to failure of the adjustability feature to the pivot bolt  14 , when further adjustment is needed to the same, during prolonged usage and application of the lever cam assemblies  12 , in holding such a manhole cover or latch  10 , onto its supporting structure or seal ring  16 . It is this detrimental feature in the design of the long used prior art style of pivot bolt  14  that the current disclosure has been conceived of, in order to remedy the conditions that lead to corrosion between the engagement of the threaded parts of the pivot bolt  14 , after a period of time. 
     The style of hardware used for a pivot bolt  100  of the present disclosure can be seen in  FIGS. 2-5 . As noted, the pivot bolt  100  is fabricated of two components, initially an upper cylindrical portion  102  and a lower bolt portion  104  as shown. The upper cylindrical portion  102  is formed of a cylinder  106 , having a channel  108  provided centrally therein, and which contains a series of threads  110  as noted. Integrally formed of the upper cylindrical member  102  is a boss like member  112  having an aperture  114  provided there through, and which accommodates the locating of a pivot pin there through, such as the second pivot pin  40  shown in  FIG. 1 , which pivot pin  40  further connects with the bifurcated arm  42  of the lever arm  26 . 
     The lower bolt portion  104  of the pivot bolt  100  includes a length of shaft  116  that also includes male threads, as at  118 , and which threadedly engage with the internal threads  110  at the interior upper cylindrical like member  106 , as previously explained. A bottom  120  of the lower bolt portion  104  includes a further boss like member  122  which includes an aperture  124 , provided there through, and which accommodates the location of the pivot pin  30 , as previously reviewed in  FIG. 1 . 
     Hence, when adjustability in the length of the pivot bolt  100  is required, as can be understood, its lower bolt portion  104  having threaded further inwardly of the upper cylindrical portion  102 , can be turned to either shorten the length of the pivot bolt  100 , or lengthen its length, as may be required in the adjustment of the pivot bolt  100  to provide for effective usage of the lever arms  26  and its camming surface  22 , upon the cover  10 , as previously explained. But what is significant is that the channel  108  into the upper cylindrical portion  102 , opens downwardly, as noted at  126 , and the threaded portion  118  of the lower bolt portion  104 , as noted at  128 , extends upwardly into the channel  108 . Hence, this is directly opposite from the exposure provided between the sleeve  46 , and the bolt  14 , as described in  FIG. 1 , particularly along the upper end of the sleeve, as noted at  48 , as previously reviewed. Thus, there is no upwardly exposed entrance to the threaded engagement between the lower bolt portion  104 , within the upper cylindrical portion  102 , and thus, prevent the entrance of any dust, debris, or moisture from inclement weather, into the adjustable pivot bolt  100  of this disclosure. The structure of the pivot bolt  100  is directly opposite from the relationship of the various components that make up the pivot bolt  14  of the prior art, as previously defined in  FIG. 1 . 
     To add further to the protection that is acquired through the assembly of the components that make up the pivot bolt  100 , as can be noted in  FIG. 5 , within a proximate lower section  130  of the upper cylindrical portion  102  is an internal groove, as at  132 , that accommodates the location of an O-ring  134  that biases against a smooth surface  136  of the lower bolt portion  104 , as it threadedly engages within the upper cylindrical member  102 , as can be understood. Since the threaded portion  118  of the lower bolt portion  104  is upwardly of the location of the O-ring  134 , the O-ring  134  provides a complete sealing against the smooth surface  136  of the lower bolt portion  104 , and the upper cylindrical portion  102 , that prevents the upward entrance of any of such debris therein, as can be understood. 
     Furthermore, as can also be noted, a bottom end  138  of the upper cylindrical portion  102 , is contoured inwardly, in close tolerance against the surface  136  of the lower bolt portion  104 , and therefore, acts as a scraper for protecting the O-ring  134 , and removes any product built up in the category of dust, debris, or even moisture, from the surface  136  of the lower bolt portion  104 , as it is inserted inwardly and threaded upwardly and within the upper cylindrical member  102 , during its assembly, and adjustment. Hence, this feature, in combination with the O-ring  134 , completely avoids the entrance of any deleterious matter into the location of the threaded engagement between these two components  102  and  104  of the pivot bolt  100 , and therefore, allows for further adjustments of these components, when the lever assemblies  12  need further adjustment, to assure a tight fitting of the manhole cover  10  upon its seal ring  16 , or other supporting structure, during prolonged usage of this improved embodiment for the pivot bolt  100  used within this assembly. 
     Hence, as can be understood, there are just no longer any exposed threads, or even access to the threads, through the usage of the aligned components that form the adjustable pivot bolt  100  of this disclosure. 
     Variations or modifications to the subject matter of this disclosure may occur to those skilled in the art upon review of the sealed manhole clamp as described herein. Such variations, if within the spirit of this disclosure, are intended to be encompassed within the scope of any claims to patent protection issuing herein. The review of the sealed manhole clamp as set forth in the Specification, and its depiction in the drawings, are primarily set forth for illustrative purposes only.