Patent Publication Number: US-2023134588-A1

Title: Self-Adjusting Band

Description:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     The invention described herein may be manufactured and used by or for the government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor. 
    
    
     BACKGROUND 
     A pressure housing is a tube that keeps the internal components dry and protects the internal components from a crushing force from external fluid. Pressure housings are used extensively in underwater systems. These systems include a stand-alone system or as a part of a system (e.g., ROV, UUV, undersea equipment) in housings that may be interconnected via cables. Due to external pressure and optimization, these vessels are often designed to be cylindrical in shape. External devices such as sensors, lights, cameras, brackets, or other hardware may need to be attached to the outside vessel wall. A band-type solution is used to attach the external devices, which wraps around the object and pressure vessel circumference. The band-type device is tensioned, which then applies force all around the pressure vessel and the external device in a radial direction. These bands are often tensioned by mechanical means such as bolts, screws, inherent locking, latching features, and integral springs to compensate for diameter changes of the clamped external devices. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       Features and advantages of examples of the present disclosure will be apparent by reference to the following detailed description and drawings, in which like reference numerals correspond to similar, but in some instances, not identical, components. Reference numerals or features having a previously described function may or may not be described in connection with other drawings in which they appear. 
         FIG.  1    is a plan view of an example of a self-adjusting band with one buckle assembly and one circumferential band segment; 
         FIG.  2    is a side view of an example of a single buckle assembly in the self-adjusting band; 
         FIG.  3    is a cross-sectional side view of an example of a single buckle assembly in the self-adjusting band; 
         FIG.  4    is an isometric view of an example of a self-adjusting band that includes five linked banding segments and five buckle assemblies; and 
         FIG.  5    is a plan view of another example of the self-adjusting band that includes an annular envelope. 
     
    
    
     DETAILED DESCRIPTION 
     Currently, there are two types of bands used to attach external devices to a pressure vessel: a static band and a spring-loaded band. The static band has a pre-load applied to the band by elastically stretching the band during the initial installation. Under hydrostatic loading, this pre-load will decrease as the pressure vessel decreases in diameter and the band will eventually return to its original un-stretched length. Therefore, the static band is only viable for very small changes in size. For example, the length of the band must change by over 6 times the change in the radius. For most metals, the material may be considered to be within the elastic region if the strain is within 0.2%. Therefore, this limits the range of contraction for a static band or the depth a static band may be used. 
     The spring-loaded band is another type of band currently being used where a compression spring or a compression element, such as a rubber strip, is used to preload the band. The spring is preloaded when the vessel is exposed to atmospheric pressure, and as the vessel is compressed by hydrostatic pressure, the spring loses pre-load and the banding decreases in effective total length. A spring-loaded band requires a large physical footprint external to the pressure vessel. The materials used for the spring are typically designed for terrestrial applications, which do not perform well in marine environments due to corrosion effects or galvanic corrosion with adjacent materials. When a compressible rubber strip is used in the spring-loaded band, many of the galvanic concerns are mitigated, but these bands have degradation issues of the rubber over time including ultraviolet damage and saltwater intrusion. This damage can cause the band to rupture or to become brittle over time, which would prevent the band from supplying the required tension to maintain the desired clamp load. 
     The self-adjusting band herein is designed to adjust the radial force exerted on the clamped external device or object based on design requirements taking into account changes resulting from the external environment. -Since the design of the band is self-adjusting, the band can be used in marine environments at a wide variety of depths, limited only by the specific disc spring configuration. Furthermore, the design does not limit the self-adjusting band to a particular material or materials. Therefore, the self-adjusting band herein can be prepared for a specific application to avoid corrosion, ultraviolet damage, or saltwater intrusion associated with other designs. Additionally, the self-adjusting band described herein can be utilized in space-constrained locations where bulky spring-loaded designs would not be feasible. 
     The self-adjusting band disclosed herein includes one or more banding segments, one or more buckling assemblies, a pair of one pin and two links for each buckle assembly, a rotary joint base for each pair of one pins and two links, and a high-load, low-deflection compression spring for each section of the buckle assembly. 
     Referring now to  FIG.  1   , a plan view of an example of the self-adjusting band  100  herein with a single buckle assembly  110 . The dashed lines in  FIG.  1    are for illustrative purposes only to aid in viewing and should not be construed as being limiting or directed to a particular material or materials. The self-adjusting band  100  shows one banding segment  112  where each banding segment contains two terminal ends with a securing mechanism at each terminal end. The single buckle assembly  110  is attached to a banding segment  112  that retains a clamped object  116  to a pressure vessel  118 . The single buckle assembly  110  includes two pins (not shown in  FIG.  1   ) and four links  102  (only two links  102  are shown in  FIG.  1   ) where each pair of one pin and two links  102  attaches to the securing mechanism of each banding segment  112 , thereby attaching one or more banding segments  112  to each other. In the example in  FIG.  1   , a single banding segment  112  with a single buckle assembly  110  can be used if the banding segment  112  is extended around the entire clamped object  116  and pressure vessel  118 . Each pair two link  102  has a rotary joint base (not shown in  FIG.  1   ) where each pair of the two links  102  attaches to the rotary joint base with a rotary joint retaining screw  108 . The rotary joint bases include a gap between the rotary joint base of each pair of the one pin and two links  102  and an opening tangent to a band segment  112  where a pre-load screw (not shown in  FIG.  1   ) is located and threaded into a coupling nut  104  that connects the rotary joint bases of each pair of one pins and two links  102 . 
     Tension loads are transferred from the banding segment  112  through each pair of the two links  102  and the coupling nut  104 . Each pair of the one pin and two links  102  allows the one or more banding segments  112  to pivot from the securing mechanism. The buckle assembly  110  is free to rotate about the axes constrained by the load segment pin retaining nut  106 , and the rotary joint retaining screw  108  of each pair of the two links  102 . The ability of the buckle assembly  110  to rotate allows overall shape changes to the system beyond circular shapes (as depicted in  FIG.  1   ). The shape of the banding segment  112  may be changed in order to maintain a tangent load path around the complete loop of the clamp system. 
     The self-adjusting band  100  may encompass one or more objects  116  to the pressure vessel  118 . Some examples of the objects include any object that that needs to stay attached to the pressure vessel  118  (e.g., fixtures), any object that needs to stay in a precise location on the pressure vessel  118 , or any object that needs to be held in contact with the wall of the pressure vessel  118 . Some specific examples include sensors (e.g., Hall Effect sensors, temperature sensors, etc.), transducers, lights, cameras, brackets, or other hardware. The pressure vessel  118  may be part of a stand-alone system or incorporated into a system, such as a remotely operated vehicle (ROV), unmanned underwater vehicle (UUV), or any other undersea equipment. 
     Referring now to  FIG.  2   , a side view of the single buckle assembly  110  is shown. The banding segments  112  are held in place with one pin  208  at each end of the buckle assembly  110 . The load is carried along each pair of the two links  102  into the rotary joint base  202 . As previously mentioned in  FIG.  1   , each buckle assembly  110  includes two pins  208  and four links  102  (i.e., a pair of one pin  208  and two links  102 ) that secure banding segments  112 . In an example, the securing mechanism at each terminal end of the banding segment  112  may be a clearance hole at the terminal ends of each banding segment  112  where each pin  208  passes through the clearance hole and threads into a load segment pin retaining nut  106 . The rotary joint base  202  also contains a horizontal clearance hole where the coupling nut  104  may slide. The coupling nut  104  is attached and preloaded through the preload screw  206  and a high-load, low-deflection compression spring  204 . The high-load, low-deflection compression spring  204  is located between the rotary joint base  202  and the preload screw  206  of each pair of one pin  208  and two links  102 . Some examples of the high-load, low-deflection compression spring  204  include a coil spring, a wave spring, a wave washer, a leaf spring washer, or a stack of Belleville-type spring washers. When the Belleville-type spring washers are used, the washers may be changed in orientation, size, material, and quantity in order to adjust the overall system clamp load and overall system self-adjustment range. 
     Throughout the self-adjusting band  100 , along sliding surfaces and between dissimilar metals, bushings  212 ,  214  are used to prevent galvanic interactions and act as motion guides for the assembly. In some examples, the buckle assembly  110  has a pair of two links  102  that further includes a load bearing bushing  212  located between the preload screw  206  and the high-load, low-deflection compression spring  204 . In other examples, the buckle assembly  110  includes including thrust bushings  214  located on an inner surface of each individual link  102  with the pin  208  passing through the thrust bushings  214 . In the example shown in  FIG.  2   , each individual link  102  has two thrust bushings  214 . Metallic washers  210  are also used to distribute clamp load from heads of the metallic fasteners to the bushings  212 ,  214  or bearings (shown in  FIG.  3   ). In one example shown in  FIG.  2   , the metallic washers  210  are located between the rotary joint retaining screw  108  and the bearing (shown in  FIG.  3   ). In another example not shown in  FIG.  2   , the metallic washers  210  are located between the inner surface of the each individual link  102  and the bushings  214 . In yet another example not shown in  FIG.  2   , the metallic washers  210  between the preload screw  206  and the bushings  212 . In yet another example not shown in  FIG.  2   , the metallic washers  210  may be located between the isolators (shown in  FIG.  3   ) and the inner surface of each individual link  102 . 
     Referring now to  FIG.  3   , a cross-sectional view of the single buckle assembly  110  is shown.  FIG.  3    is the same example shown in  FIG.  2   , but shows the internal orientation of the buckle assembly  110 . The dashed and hatching lines in  FIG.  3    are for illustrative purposes only to aid in viewing and should not be construed as being limiting or directed to a particular material or materials. In the example shown in  FIG.  3   , the buckle assembly  110  includes bearings  302  and isolators  304 . The bearings  302  are located between the rotary joint retaining screw  108  and an outer surface of each individual link  102 . The bearings  302  are used to allow free articulated movement of the self-adjusting band  100  as the self-adjusting band  100  is modified due to a changing clamp surface. The bearings  302  also prevent galvanic interactions. The isolators  304  are located between the inner surface of each individual link  102  and the high-load, low-deflection compression spring  204 . In this configuration, the isolators  304  are used to provide a sliding surface and galvanic isolation from the washers  210  (e.g., Belleville-type washers), which allows the rotary joint base  202  to pivot and allows use of various marine-grade materials for the springs. As previously mentioned in  FIG.  2   , metallic washers  210  are used to distribute clamp load from heads of the metallic fasteners to isolators  304 . 
     Referring now to  FIG.  4   , an isometric view of another example of the self-adjusting band  100  is shown. The dashed lines in  FIG.  4    are for illustrative purposes only to aid in viewing and should not be construed as being limiting or directed to a particular material or materials. In this example, the self-adjusting band  100  has five buckle assemblies  110  and five banding segments  112 . The buckle assemblies  110  and the banding segments  112  are the same buckle assemblies  110  and banding segments  112  as previously described herein. The self-adjusting band  100  encloses a pressure vessel  118  with a clamped object  116  secured to the pressure vessel  118 .  FIG.  4    also shows a radial interface adapter  114  that is located between the clamped object  116  and the banding segment  112  to conform to the shape of the banding. The radial interface adapter  114  conforms the one or more banding segments  112  to a surface of the object  116  and the pressure vessel  118 . The radial interface adapter  114  may also provide a uniform surface for the banding to clamp to, even if the underlying objects being clamped is non-uniformly shaped. 
     Although the example in  FIG.  4    shows the self-adjusting band  100  with five buckle assemblies  110  and five banding segments  112 , the self-adjusting band  100  is not limited to a specific amount of buckle assemblies  110  and banding segments  112 . There can be one buckle assembly  110  and banding segment  112  or as many as needed to encompass the pressure vessel  118  and the clamped object  116  or provide additional actuation range. In addition, in the example shown in  FIG.  4   , each buckle assembly  110  and banding segment  112  is identical, and the buckle assembly  110  is symmetric about the coupling nut. However, the self-adjusting band  100  may have different sizes or shapes of banding segments  112  or buckle assemblies  110  depending on the clamping requirements, clearances to external components, or a combination of both clamping requirements and clearances to external components. Furthermore, the buckle assembly  110  and banding segments  112  may be made with any known material that can adequately produce the self-adjusting band  100 . 
     Referring now to  FIG.  5   , a plan view of another example of the self-adjusting band  100  is shown. The dashed lines in  FIG.  5    are for illustrative purposes only to aid in viewing and should not be construed as being limiting or directed to a particular material or materials. Similar to  FIG.  4   , in this example, the self-adjusting band  100  has five buckle assemblies  110  and five banding segments  112 . The buckle assemblies  110  and the banding segments  112  are the same buckle assemblies  110  and banding segments  112  as previously described herein. In this example, the self-adjusting band  100  is shown within an annular operating envelope  502 , which demonstrates the low-profile nature of the device, allowing it to operate in geometrically constrained environments. 
     As used herein, the term “about” is used to provide flexibility to a numerical range endpoint by providing that a given value may be “a little above” or “a little below” the endpoint. The degree of flexibility of this term can be dictated by the particular variable and would be within the knowledge of those skilled in the art to determine based on experience and the associated description herein. 
     As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of a list should be construed as a de facto equivalent of any other member of the same list merely based on their presentation in a common group without indications to the contrary. 
     Unless otherwise stated, any feature described herein can be combined with any aspect or any other feature described herein. 
     Reference throughout the specification to “one example”, “another example”, “an example”, means that a particular element (e.g., feature, structure, and/or characteristic) described in connection with the example is included in at least one example described herein, and may or may not be present in other examples. In addition, the described elements for any example may be combined in any suitable manner in the various examples unless the context clearly dictates otherwise. 
     In describing and claiming the examples disclosed herein, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.