Abstract:
A hydrostatic testing tool for testing containers, hoses or the like under high pressures. The testing tool having a coupling that threadably engages a threaded aperture of a test container without having to be rotated into the threaded aperture. The hydrostatic testing tool may be hooked up to a source of pressurized medium and the tool includes a container-engaging head having a plurality of collet segments that each have a threaded surface that can expand radially outward, partially due to the force of the pressurized medium, to engage a threaded aperture of the test container, allowing for the formation of a liquid and/or gas tight seal under high pressures. The testing tool further includes an actuating unit connected to the head that controls the movement of the collet segments with a piston or the like.

Description:
RELATED APPLICATION 
     The present application is related to and claims priority to U.S. Patent Application Ser. No. 60/888,624, filed Feb. 7, 2007, currently pending, and is titled HYDROSTATIC TESTING TOOL AND METHOD OF USE, wherein the aforementioned application is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a hydrostatic testing tool. Particularly, the present invention relates to a hydrostatic testing tool having a coupling that threadably engages a threaded aperture of a test article without having to be rotated into the threaded aperture. More particularly, the present invention relates to a hydrostatic testing tool, which has a plurality of threaded collet segments that can expand radially outward to engage a threaded aperture of a test article to form a junction between the testing tool and the test article, which provides a liquid tight seal when the testing tool is operatively secured to the test article. 
     2. Description of the Related Art 
     Hydrostatic testing tools are used for testing the strength and integrity of test articles such as, metal bottles, containers, pressure carrying hoses and the like, wherein the bottle, container or hose generally has a filler/discharge aperture with an internal, threaded female coupling. 
     Typical containers to be tested must be able to safely contain gases and liquids stored at high pressures. The containers have various commercial applications but are often used, for example, in the medical equipment industry for storage of gases and gaseous liquids under high pressure. Typically, the containers will have an internal volume ranging between about 0.5 cubic feet to about 1.5 cubic feet. The containers are generally tested for strength using pressures of more or less than about 6000 pounds per square inch. 
     Each article to be tested will have an internal thread on its filler/discharge aperture. When these articles are tested, the test equipment is usually attached to the threaded aperture of the articles in one of two known ways. The first method is to rotate a threaded end of the testing tool into the threaded aperture of the article to produce a tight seal. This method generally requires complex automatic equipment to do the threading and unthreading needed to connect the tool to the large quantity of articles that are typically tested in a given time interval. This could be done by hand, but however it is done, it is extremely time consuming and limits the rate of test production. 
     The second known method is to insert an expandable rubber plug into the threaded aperture of the container and to then mechanically expand the rubber plug to sealably engage the threaded aperture. This method has not been shown to provide a reliable seal between the test article and testing tool. 
     The present invention addresses limitations and problems associated with the prior art. 
     SUMMARY OF THE INVENTION 
     The present invention provides a hydrostatic testing tool for testing a test article, such as a container, having a threaded aperture. The testing tool comprising an actuator unit and a head interconnected to the actuator unit. The head including a collet body having a plurality of collet segments collectively forming a cylindrical outer perimeter having a variable diameter, each collet segment having a threaded surface on the outer perimeter such that the actuator unit can selectively vary the diameter of the outer perimeter. 
     It is an object of the present invention to provide a hydrostatic testing tool that may be quickly secured and unsecured to a threaded aperture of a test article, such as a container, hose or the like. It is another object of the present invention to provide a hydrostatic testing tool that is durable, provides a reliable seal and cannot become dislodged from the threaded aperture during testing. 
     Preferred embodiments of the present invention achieve these and other objectives by providing a hydrostatic testing tool including a container-engaging head. The head preferably includes a generally cylindrical attachment body that is connected to an actuator unit having a central channel. The actuator unit preferably has a rear end where an inlet aperture can be sealably attached, in any known way, to a source of high-pressure fluid such as, gas, liquid or the like, preferably liquid, during testing. The pressurized fluid entering the inlet aperture preferably flows along the central channel toward the head of the tool. 
     The head of preferred embodiments further includes a longitudinally extending central chamber which communicates with the central channel of the actuator unit. The head of preferred embodiments additionally has a hollow cylindrical sleeve which is slidably received into, and contained within, the chamber. The sleeve is retained within the chamber by a retaining snap ring after being slid into the chamber from the front end of the head. 
     The head of preferred embodiments further includes an attachment body that houses a collet body of generally cylindrical configuration which is inserted into the chamber of the head from the rear end of the head before the head is threaded onto the actuator unit. The collet body of preferred embodiments includes a plurality of collet segments having a cylindrical outer perimeter. The collet segments of preferred embodiments are somewhat pie wedge shaped in cross section, movable relative to each other and fit together to generally form a cylindrical shape. All of the collet segments, when properly aligned with each other, cooperate to define a generally continuous thread around the cylindrical outer perimeter that corresponds to or mates with the threaded aperture of the test article. 
     The collet body of preferred embodiments further includes an annular ring slot near its rearmost end. A removable two-piece split lock ring is slipped into the ring slot of preferred embodiments and helps lock the collet body in place relative to the attachment body. The front of the actuator unit of this embodiment bears against the two-piece lock ring when the actuator unit is connected to the head. In essence, the two-piece ring restricts (but does not wholly prevent) the collet body from moving forward, and the actuator unit restricts (but does not wholly prevent) the collet body and the lock ring from moving rearward. The ability of the collet segments to move forward and rearward, however slight, allows the collet segments to slightly adjust their longitudinal positions relative to one another to align with the threaded aperture. The collet body of this embodiment has an internal longitudinal channel extending rearwardly along its central axis from the front of the collet body and communicating with the actuator unit channel. A sliding piston, which is retained and selectively controlled by the actuator unit, can move forward and rearward along the central axis of the channel to radially expand the collet segments outwardly to engage the threaded aperture. In preferred embodiments, the testing tool further includes a sleeve or knurled knob, such that when the knob is rotated, the seal between the testing tool and the test article is enhanced. 
     The piston of this embodiment includes an internal piston channel extending from its rear end and communicating with the central channel. The piston channel ends midway along the piston where two smaller piston ports extend forwardly and outward to the outer periphery of the piston to allow pressurized fluid material, such as gas or liquid, to flow from the piston channel and along the piston ports to reach the collet segments. 
     Referring again to the channel formed along a central longitudinal axis of the collet body of this embodiment, the sliding piston is positioned within the channel for forward and rearward movement along the central axis of the collet body. As the piston moves forward, an annular shoulder of the piston contacts shoulders of the collet segments and pushes the collet segments radially outward from the central axis from an initial rest or unexpanded position to an expanded position, causing the diameter of the cylindrical outer perimeter of the threaded collet segments to increase uniformly along the collet body length so that the threaded collet segments strongly, mateably and evenly engage the threaded aperture so as to reliably seal the junction between the testing tool and the test article and retain the test article during high pressure testing. 
     The collet body of preferred embodiments additionally has front and rear annular slots each retaining a biasing device, such as a stretchable O-ring, snap ring or the like, that applies a force to urge the collet segments radially inward and together so as to retain and return the collet segments to an initial, unexpanded position. When the collet segments of preferred embodiment are in the unexpanded position, the cylindrical outer perimeter diameter is small enough to allow the collet segments to slide longitudinally within the threaded aperture of the container. When the collet segments are in a radially expanded position, the diameter of the cylindrical outer perimeter is increased to closely match, tightly engage and retain the threaded aperture. 
     When the collet segments of the preferred embodiment are in a radially expanded position, there is a gap created between each collet segment that reduces the risk of the fluid material flow path becoming obstructed and allows pressurized fluid material, preferably liquid, to flow through the gaps to enter into the test article. 
     The biasing devices of preferred embodiments allow the separate collet segments to move forwardly or rearwardly, slightly and independently of each other so as to permit the respective threaded surfaces to independently self-align with the threaded aperture and to more readily engage the threaded aperture when portions of the threaded aperture are somewhat irregular or damaged. 
     A wave spring is positioned within the central chamber preferred embodiments and extends between a rear shoulder of the head and an outwardly extending annular sleeve flange on the sleeve to spring bias the sleeve forwardly toward and against the retaining snap ring. At the front end of the sleeve is a sleeve slot in which a sealing O-ring resides in preferred embodiments. The wave spring and the sealing O-ring devices play an important role in creating an effective seal between the front end of the testing tool and the container or other test article. 
     When a container or other test article is to be tested, the collet segments of preferred embodiments are placed in an unexpanded position. The unexpanded collet segments can then be inserted into the threaded aperture of the container. As the testing tool is pressed against the container, the sleeve is pushed rearwardly by the container against the wave spring of preferred embodiments so as to cause the wave spring to bias the sleeve against the container. At this time, the actuator unit is activated to force the piston forward and into the collet body, causing the collet segments to move radially outward to an expanded position and solidly, threadably engage the threaded aperture of the container. Because the wave spring is now forcing the sleeve against the container, the sleeve O-ring in the front slot becomes compressed. At the contact circle between the container and the sleeve, the O-ring in the front slot is compressed between the container, the sleeve and the collet body to form a tight seal. 
     Preferably, the annular front slot has an angled front wall that slants rearwardly to better retain the O-ring and prevent it from escaping from the front slot during the forward and rearward movement of the sleeve relative to the O-ring When the pressure is applied to the testing tool of preferred embodiments, the pressure also cooperates with the wave spring, sleeve and the container to force the O-ring against the container and further improve the seal therebetween. 
     The testing tool and methods of preferred embodiments of the present invention are much faster and easier to use than known methods that employ rotating a threaded end of the testing tool into the threaded aperture of the test article to produce a tight seal. Although that prior method works, it is time consuming to have to thread and unthread the testing tool from the threaded aperture and, assuming it is not done by hand, which would be really slow, it also requires complex automatic equipment to do the threading and unthreading needed to connect the tool to the large quantity of test articles that are typically tested in a given time interval. 
     The testing tool and methods of the present invention are also much safer and more reliable than the known expandable rubber plug method that involves inserting a rubber plug into the threaded aperture of the container and to then mechanically expanding the plug to sealably engage the threaded aperture. This known rubber plug method, when used at high pressures, has been unreliable and has created safety problems in that as the rubber plug wears, the container can sometimes slip off the rubber plug. When it does slip off, the container may be “launched” at high speed from the plug as the high pressure fluid within the container under test is released, resulting in a flying container that can endanger anyone or anything in its path. 
     These and various other advantages and features of novelty which characterize the present invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages and objects obtained by its use, reference should be made to the drawings of preferred embodiments of the present invention, which form a further part hereof, and to the accom panying descriptive matter, in which there is illustrated and described preferred embodiments of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, in which corresponding reference numerals and letters indicate corresponding parts of the various embodiments throughout the several views, and in which the various embodiments generally differ only in the manner described and/or shown, but otherwise include corresponding parts; 
         FIG. 1A  is a perspective view of a preferred hydrostatic testing tool  10  of the present invention in an unexpanded position; 
         FIG. 1B  is a side view of the testing tool  10  of  FIG. 1A ; 
         FIG. 2A  is a perspective view, similar to that of  FIG. 1A , of the testing tool  10  of  FIGS. 1A-1B , illustrating the testing tool in an expanded position; 
         FIG. 2B  is a side view of the testing tool  10  shown in  FIG. 2A ; 
         FIG. 3  is a partial, cross-sectional view of the testing tool  10  as viewed along line  3 - 3  of  FIG. 2B , illustrating the interior components of the testing tool including an actuator unit  12  having a central channel  18  that is interconnected to a head  40  having a collet body  66  with a channel  68  that is surrounded by a sleeve  52 ; and a piston  100  operatively connected within the actuator or central channel  18  and the collet channel  68  but showing the entire wave spring  112  as it would be seen from line  3 - 3  and not showing threaded fittings of the embodiment illustrated in  FIG. 1A ; 
         FIG. 4  is an expanded cross-sectional view of the collet body  66  of  FIG. 3  illustrating the collet channel  68 ; 
         FIG. 5  is an expanded cross-sectional view of the piston  100  of  FIG. 3 ; 
         FIG. 6  is an expanded cross-sectional view of the sleeve  52  of  FIG. 3 ; 
         FIG. 7  is a partially exploded, perspective view of the testing tool  10  of  FIGS. 1A-1B  illustrating the actuator unit  12  and a container-engaging head  40 ; 
         FIG. 8  is an end view of a rear end  44  of the container-engaging head  40  of  FIG. 7 ; 
         FIG. 9A  is a perspective view of a preferred alternate hydrostatic testing tool  10 ′ in an expanded position; 
         FIG. 9B  is side view of the testing tool  10 ′ of  FIG. 9A ; 
         FIG. 10  is a cross-sectional view of the testing tool  10 ′ as viewed along line  10 - 10  of  FIG. 9B ; 
         FIG. 11  is a perspective view of the testing tool  10 ′ before insertion into a threaded aperture T of a container C that is to be tested; 
         FIG. 12A  is a cross-sectional view of the testing tool  10 ′ of  FIG. 11  as it is inserted into the threaded aperture T in the unexpanded position; and 
         FIG. 12B  is a cross sectional view of the testing tool  10 ′ of  FIGS. 11-12A , when the testing tool  10 ′ is in the expanded position. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Preferred embodiments of the present invention are illustrated in  FIGS. 1-12B . Referring in particular now to  FIGS. 1-3  and  7 - 8 , one embodiment of a hydrostatic testing tool  10  includes an actuator unit  12  interconnected to an article or container-engaging head  40 . The head  40  is a generally cylindrical structure that includes a front end  42 , a rear end  44  and an attachment body  48  which threads onto the actuator unit  12  at junction  50 . The actuator unit  12  has a rear end  14  and at the rear end  14  is an inlet aperture  16  that is sealably attached in any known way to a source of high-pressurized fluid material (not shown), preferably liquid, for testing. It should be understood that although the inlet aperture  16  is described as for receiving liquid, the testing tool  10  of the present invention will work with gases as well. The pressurized liquid entering inlet aperture  16  flows along a central channel  18  in a direction towards the head  40 . It will be appreciated that the container engaging head can engage test articles other than containers and the present invention is not, therefore, limited to use with any particular test articles. 
     Referring in particular now to FIGS.  1 A and  3 - 5 , the head  40 , further has a longitudinally extending central chamber  68  that communicates with the channel  18  of the actuator unit  12 . The head  40  also includes a hollow cylindrical sleeve  52 , which is slidably received into and contained within the chamber  64 . The sleeve  52  is preferably retained within the chamber  64  by a retaining, snap ring  54  or the like, after the sleeve  52  is slid into the chamber  64  from the front end  42  of the head  40 . 
     The head  40  further includes a generally cylindrical collet body  66  that is inserted into the chamber  68  from the rear end  44  of the head  40  before the head is connected, preferably threadably attached, to the actuator unit  12 . The preferred collet body  66  has a plurality of collet segments  70  and an annular ring slot  84  near its rear end. A removable two-piece split lock ring  86  is slipped into the ring slot  84  and helps lock the collet body  66  in place relative to the attachment body  48 . The actuator unit  12  bears against the two-piece split lock ring  86  when the actuator unit  12  is connected to the head  40 . In essence, the split lock ring  86  restricts (but does not wholly prevent) the collet body  66  from moving forward, and the actuator unit  12  restricts (but does not wholly prevent) the collet body  66  and the split lock ring  86  from moving rearward. Such forward and rearward movement, however slight, allows the collet segments  70  to slightly adjust their longitudinal positions relative to one another. The collet body  66  has an internal longitudinal chamber  68  extending rearwardly along its central axis from the front of the collet body  66  and communicates with the actuator unit channel  18 . A sliding piston  100 , which is retained and selectively controlled by the actuator unit  12 , moves forward and rearward along the central axis of the collet channel  68  to radially expand the collet body  66  inward and outward, as is described in more detail below. 
     The piston  100  has an internal piston channel  102  extending from its rear end and communicating with the central channel  18 . The channel  102  ends midway along the piston  100  at the channel end  104  where two smaller piston ports  106  extend forwardly and outward to the outer periphery of the piston  100  to allow pressurized liquid to flow from the channel  102  and along the ports  106  to reach the collet body  66 . A spring  114  maintains contact between the actuator assembly  22  and the rear body  14  for extending and retracting of the piston  100  from the collet body  66 . Extending the piston  100  causes the collet body  66  to expand and grip the threaded aperture T of a test article or container C, while retracting the piston  100  allows the collet body  66  to constrict and release its grip on the threaded aperture T. 
     The preferred collet body  66  has six collet segments  70 , which are somewhat pie wedge shaped in cross-section, moveable relative to each other and which fit together to from a cylindrical outer perimeter  72  having a diameter “D”. Each of the collet segments  70  has a threaded surface  76  around the cylindrical outer perimeter  72  near its front end  78  and the threaded surface  76  corresponds to a threaded surface defining the threaded aperture T of the test container C (see also,  FIG. 11 ). All of the collet segments  70 , when properly aligned with each other, cooperate to define a generally continuous threaded surface  76  around the cylindrical outer perimeter  72  of the collet segments  70 , which corresponds to the threaded aperture T of the test container C. The generally continuous threaded surface  76  is separated by the area between the respective collet segments  70 . 
     Referring again to the channel  68  formed along the central longitudinal axis of the collet body  66 , the sliding piston  100  is positioned within the channel  68  and the chamber  64  for forward and rearward movement along the central axis of the collet body  66 . Referring now also to  FIGS. 3-6 , as the piston  100  moves forward, an annular shoulder  108  of the piston  100  contacts shoulders  80  and  82 , respectively on the collet segments  70  (see,  FIG. 4 ) and pushes the collet segments  70  radially outward from the central axis from an initial rest or unexpanded position (see  FIG. 1B ) to an expanded position (see  FIG. 2B ), causing the unexpanded diameter “D” of the cylindrical outer perimeter  72  to increase uniformly to a second diameter “D 2 ” so that the threaded collet segments  70  strongly, mateably and evenly engages the threaded aperture T so as to reliably retain the container C on the testing tool  10  during high pressure testing. 
     The preferred actuator unit  12  is illustrated in  FIGS. 1-3 .  FIGS. 1A and 1B  show the preferred actuator unit  12  further including a body  20  interconnected to an actuator assembly  22  having a generally cylindrical portion  24  and a lever  28  extending laterally through the generally cylindrical portion  24 . Preferably, the generally cylindrical portion  24  is interconnected, off-center, to a collar  30  circumscribing a shaft  32  that is operatively connected to the piston  100 . The preferred generally cylindrical portion  24  includes a recess  26  such that when the lever  28  is rotated, the generally cylindrical portion  24  correspondingly rotates. As shown in  FIGS. 1A and 1B , when the generally cylindrical portion  24  is rotated far enough such that the body  20  enters the recess  26 , the collar  30  and the shaft  32 , are pushed rearwardly, thus moving the piston  100  (see  FIG. 3 ) rearwardly as well and placing the collet segments  70  in the unexpanded position. As shown in  FIGS. 2A and 2B , when the lever  28  is further rotated as to forcedly position the body  20  outside of the recess  26 , the collar  30  and the shaft  32 , and thus the piston  100 , slide forward and the collet segments  70  move into the engaged position. In preferred embodiments, the generally cylindrical portion  24  will include two recesses  26  approximately 180 degrees from each other so that generally cylindrical portion  24  requires less rotation to un-expand the collet segments  70 . It is noted that this is simply the preferred actuator unit and that any other known plunging device can be used to control the movement of the piston. It will be understood that the actuating unit can be actuated either mechanically or pneumatically. 
     The collet body  66  is preferably, first formed as an integral, cylindrical stainless steel unit, and the threaded surface  76  is then cut into the outer perimeter  72  near the front end  78  of the collet body  66  so as to correspond to the threaded aperture T. The central channel  68  is then bored longitudinally through the collet body  66  along the central axis, and the shoulders  80  and  82  may be machined within the collet body  66  during the boring operations. At this stage, the collet body  66  is cut along three radial planes into the six collet segments  70 , or, alternatively, as many or as few radial planes as needed to create the desired number of collet segments. It should be noted that the threaded surface  76  on each collet segment  70  is likely to be different in alignment from the other collet segments, and, therefore, the segments are preferably aligned in the same order as that which existed before cutting in order that the threaded surfaces as a whole retains its original nature on the collet body. 
     As best shown in  FIGS. 3-4 , the preferred collet body  66  has front and rear annular slots  88 ,  90  extending about its outer periphery and a biasing device  92 , such as a stretchable O-ring, snap ring or the like is received into each of the front and rear slots  88 ,  90  to apply a force to urge the collet segments  70  radially inward and together so as to retain and return the collet segments  70  to an initial unexpanded position. When the collet segments  70  are in the unexpanded position, the cylindrical outer perimeter  72  should have a diameter “D” small enough to allow the threaded surfaces  76  to slide longitudinally within the threaded aperture T of the container C (see also,  FIG. 11 ). When the collet segments  70  are in a radially expanded position, the original diameter “D” of the cylindrical outer perimeter  72  is increased to the second diameter “D 2 ′” that closely matches, tightly engages and retains the threaded aperture T. When the collet segments  70  are in a radially expanded position, there is a gap  74  created between each collet segment  70  (See  FIG. 2A ) that reduces the risk of the fluid material or liquid flow path becoming obstructed and allows pressurized liquid to flow through the gaps  74  and enter into the container C. 
     The use of the biasing devices  92  in the front and rear slots  88 ,  90  of the collet body  66  allows the separate segments  70  of the collet body  66  to move forwardly or rearwardly, slightly and independently of each other so as to have their respective threaded surfaces  76  be more self-aligning with the threaded aperture T and even to more readily engage the threaded aperture when the threaded aperture may be somewhat irregular or damaged. The preferred biasing device  92  is an O-ring made of BUNA (nitrile), but the preferred material may vary depending on the substance to be pressurized as will be determinable by one of ordinary skill in the art in light of this disclosure. It will be appreciated that O-rings made of other suitable materials may also be used. 
     Referring now also to  FIGS. 3-6 , a wave spring  112  is positioned within the chamber  64  of the head  40  and extends between a rear shoulder  46  of the head  40  and an outwardly extending annular sleeve flange  60  of the sleeve  52  to spring bias the sleeve  52  forwardly toward and against the retaining ring  54 . At the front end of the sleeve  52  is a sleeve slot  56 , which preferably contains a sealing O-ring  62  or the like. The slot  56  cross-section is best shown in  FIG. 6 . The wave spring  112  and the O-ring  62  in the sleeve slot  56  play an important role in creating an effective seal between the front end of the tool  10  and the container and are best understood in conjunction with the following description of how the tool engages and seals the container. 
     When a container C is to be tested, the collet segments  70  are placed in their unexpanded positions so that the collet segments fit within the threaded aperture T of the test container aperture C. The unexpanded collet segments  70  are slidably inserted into the threaded aperture of the container. As the tool  10  is pressed against the container, the sleeve  52  is pushed rearwardly by the container against the wave spring  112  so as to cause the wave spring to bias the sleeve  52  against the container. At this time the actuator unit  12  is activated to force the piston  100  forward and into the collet body  66 , causing the collet segments  70  to move radially outward to expanded position and solidly, threadably engage the threaded aperture of the container. This results in the container being fixed relative to and “locked on” to the collet body  66 . Because the wave spring  112  is forcing the sleeve  52  against the container, the O-ring  62  in the sleeve slot  56  becomes compressed. At the contact circle between the container and the sleeve  52 , the O-ring  62  is compressed between the container, the sleeve  52  and the collet body  66  to form a tight seal. 
     As best shown in  FIG. 6 , the sleeve slot  56  has an angled front wall  58  that slants rearwardly to better retain the O-ring  62  and prevent the O-ring from escaping from the sleeve slot  56  during the forward and rearward movement of the sleeve  52  relative to the O-ring  62 . When the pressure is applied to the tool  10 , the pressure also cooperates with the wave spring  112 , sleeve  52  and the container to force the O-ring  62  against the container and further improve the seal therebetween. 
     Referring again to  FIG. 3 , the preferred testing tool  10  further includes a plurality of O-rings  94  positioned throughout the actuator unit  12  and the head  40 . These O-rings  94  function as seals for the actuation of the internal parts of the tool  10  and their placement and usage will be apparent to one of ordinary skill in the art in light of this disclosure. 
       FIGS. 9A-10  illustrate another embodiment of a hydrostatic testing tool  10 ′ largely similar to the embodiment illustrated in  FIGS. 1-8 , which was subsequently developed and is believed to be preferred. The testing tool  10 ′ includes an actuator unit  12 ′ interconnected to a container-engaging head  40 ′. As in the previous embodiment, the head  40 ′ is a generally cylindrical structure that includes a front end  42 ′, a rear end  44 ′ and an attachment body  48 ′ which threads onto the actuator unit  12 ′ at junction  50 ′. The actuator unit  12 ′ has a rear end  14 ′ and at the rear end  14 ′ is an inlet aperture  16 ′ that is sealably attached in any known way to a source of high-pressure fluid material such as liquid or gas for testing (see in particular,  FIG. 10 ). The pressurized liquid or gas entering inlet aperture  16 ′ flows along a central channel  18 ′ in a direction towards the head  40 ′. 
     Referring in particular now to  FIG. 10 , the head  40 ′, further has a longitudinally extending central chamber  68 ′ which communicates with the channel  18 ′ of the actuator unit  12 ′. The head  40 ′ also includes a hollow cylindrical sleeve  52 ′ which is slidably received into and contained within the chamber  64 ′. The sleeve  52 ′ is preferably retained within the chamber  68 ′. 
     The head  40 ′ further includes a generally cylindrical collet body  66 ′ that is inserted into the chamber  68 ′ from the rear end  44 ′ of the head  40 ′ before the head is connected, preferably threadably attaching, to the actuator unit  12 ′. The preferred collet body  66 ′ has a plurality of collet segments  70 ′ and an annular ring slot  84 ′ near its rear end. A removable two-piece split lock ring  86 ′ is slipped into the ring slot  84 ′ and helps lock the collet body  66 ′ in place relative to the attachment body  48 ′. The actuator unit  12 ′ bears against the two-piece split lock ring  86 ′ when the actuator unit  12 ′ is connected to the head  40 ′. In essence, the split lock ring  86 ′ restricts (but does not wholly prevent) the collet body  66 ′ from moving forward, and the actuator unit  12 ′ restricts (but does not wholly prevent) the collet body  66 ′ and the split lock ring  86 ′ from moving rearward. As with the previous embodiment, such forward and rearward movement, allows the collet segments  70 ′ to slightly adjust their longitudinal positions relative to one another. The collet body  66 ′ has an internal longitudinal chamber  68 ′ extending rearwardly along its central axis from the front of the collet body  66 ′ and communicates with the actuator unit channel  18 ′. A sliding piston  100 ′, which is retained and selectively controlled by the actuator unit  12 ′, moves forward and rearward along the central axis of the collet channel  68 ′ to radially expand the collet body  66 ′ inward and outward. 
     The piston  100 ′ has an internal piston channel  102 ′ extending from its rear end and communicating with the central channel  18 ′. The channel  102 ′ ends midway along the piston  100 ′ at the channel end  104 ′ where two smaller piston ports  106 ′ extend forwardly and outward to the outer periphery of the piston  100 ′ to allow pressurized liquid to flow from the channel  102 ′ and along the ports  106 ′ to reach the collet body  66 ′. A spring  114 ′ maintains contact between the actuator assembly  22 ′ and the rear body  14 ′ for extending and retracting of the piston  100 ′ from the collet body  66 ′. Extending the piston  100 ′ causes the collet body  66 ′ to expand and grip the threaded aperture T of a test article or container C, while retracting the piston  100 ′ allows the collet body  66 ′ to constrict and release its grip on the threaded aperture T (see also,  FIGS. 12A-12B ). 
     As illustrated in  FIG. 9A , the preferred collet body  66 ′ has six collet segments  70 ′, which are somewhat pie wedge shaped in cross-section, movable relative to each other and which fit together to from a cylindrical outer perimeter  72 ′. Each of the collet segments  70 ′ has a threaded surface  76 ′ around the cylindrical outer perimeter  72 ′ near its front end and the threaded surface  76 ′ corresponds to a threaded surface defining the threaded aperture T of the test container C (see,  FIG. 11 ). All of the collet segments  70 ′, when properly aligned with each other, cooperate to define a generally continuous threaded surface  76 ′ around the cylindrical outer perimeter  72 ′ of the collet segments  70 ′, which corresponds to the threaded aperture T of the test container C. The generally continuous threaded surface  76 ′ is separated by the area between the respective collet segments  70 ′. 
     Referring again to the channel  68 ′ formed along the central longitudinal axis of the collet body  66 ′, the sliding piston  100 ′ is positioned within the channel  68 ′ and the chamber  64 ′ for forward and rearward movement along the central axis of the collet body  66 ′. As the piston  100 ′ moves forward, an annular shoulder  108 ′ of the piston  100 ′ contacts shoulders  80 ′ and  82 ′, respectively on the collet segments  70 ′ and pushes the collet segments  70 ′ radially outward from the central axis from an initial rest or unexpanded position (see also,  FIG. 1A ) to an expanded position (as illustrated in  FIG. 9A ), causing the unexpanded diameter of the cylindrical outer perimeter to increase uniformly to a second diameter so that the threaded collet segments  70 ′ strongly, mateably and evenly engages the threaded aperture T so as to reliably retain the container C on the testing tool  10 ′ during high pressure testing. 
     The preferred actuator unit includes a body  20 ′ interconnected to an actuator assembly  22 ′ having a generally cylindrical portion  24 ′ and a lever  28 ′ extending laterally through the generally cylindrical portion  24 ′. Preferably, the generally cylindrical portion  24 ′ is interconnected, off-center, to a collar  30 ′ circumscribing a shaft  32 ′ that is operatively connected to the piston  100 ′. The preferred generally cylindrical portion  24 ′ includes a recess  26 ′ such that when the lever  28 ′ is rotated, the generally cylindrical portion  24 ′ correspondingly rotates. When the generally cylindrical portion  24 ′ is rotated far enough such that the body  20 ′ enters the recess  26 ′, the collar  30 ′ and the shaft  32 ′, are pushed rearwardly, thus moving the piston  100 ′ rearwardly as well and placing the collet segments  70 ′ in the unexpanded position (see also,  FIG. 1A ). When the lever  28 ′ is further rotated as to forcedly position the body  20 ′ outside of the recess  26 ′, the collar  30 ′ and the shaft  32 ′, and thus the piston  100 ′, slide forward and the collet segments  70 ′ move into the engaged position. In preferred embodiments, the generally cylindrical portion  24 ′ will include two recesses  26 ′ approximately 180 degrees from each other so that generally cylindrical portion  24 ′ requires less rotation to un-expand the collet segments  70 ′. As with the previous embodiment, the actuator unit shown is simply the preferred actuator unit and that any other known plunging device may be used to control the movement of the piston. It will be understood that the actuating unit can be actuated either mechanically or pneumatically. 
     Referring also to  FIGS. 10 ,  12 A and  12 B, similar to the previous embodiment, the preferred collet body  66 ′ has front and rear annular slots  88 ′,  90 ′ extending about its outer periphery and a biasing device  92 ′, such as a stretchable O-ring, snap ring or the like is received into each of the front and rear slots  88 ′,  90 ′ to apply a force to urge the collet segments  70 ′ radially inward and together so as to retain and return the collet segments  70 ′ to an initial unexpanded position. When the collet segments  70 ′ are in the unexpanded position, the cylindrical outer perimeter  72 ′ should have a diameter small enough to allow the threaded surfaces  76 ′ to slide longitudinally within the threaded aperture T of the test article or container C. When the collet segments  70 ′ are in a radially expanded position, the original diameter of the cylindrical outer perimeter  72 ′ is increased to the second diameter that closely matches, tightly engages and retains the threaded aperture T of the container C (see,  FIG. 12B ). When the collet segments  70 ′ are in a radially expanded position, there is a gap  74 ′ created between each collet segment  70 ′ (See  FIG. 9A ) that reduces the risk of the fluid material flow path becoming obstructed and allows pressurized fluid material to flow through the gaps  74 ′ and enter into the container C. 
     The use of the biasing devices  92 ′ in the front and rear slots  88 ′,  90 ′ of the collet body  66 ′ allows the separate segments  70 ′ of the collet body  66 ′ to move forwardly or rearwardly, slightly and independently of each other so as to have their respective threaded surfaces  76 ′ be more self-aligning with the threaded aperture T and even to more readily engage the threaded aperture when the threaded aperture is somewhat irregular or damaged. 
     In this preferred embodiment, the testing tool  10 ′ further includes a knob  120 ′. The knob  120 ′ preferably has a knurled surface  122 ′ so that it is easy to grip and rotate. The knob  120 ′ rotates relative to the front end  42 ′ which has internal threads. When a user rotates the knob  120 ′ in the clockwise direction relative to the right end view of the testing tool  10 ′, the knob  120 ′ will move away from end of the front end  42 ′. During use, the knob  120 ′ is preferably only rotated clockwise after the collet body  66 ′ is securely engaged with the threaded aperture T of the container C. By rotating the knob  120 ′ clockwise it causes a face seal  62 ′ retained in the knob  120 ′ to be pressed against the container C resulting in compression of the face seal  62 ′ to create a leak tight condition superior to that of the embodiment of  FIGS. 1A-8 . The force of compressing the face seal  62 ′ is reacted by the collet body  66 ′ gripping the threaded aperture T. After testing tool  10 ′ usage where the collet segments  70 ′ of the collet body  66 ′ are released and not gripping the threaded aperture T, the knob  120 ′, is rotated counterclockwise to reset the knob  120 ′ for the next application. 
     To further increase the seal between the testing tool  10 ′ and the container C, the sleeve slot  56 ′ has an angled front wall  58 ′ that slants rearwardly to better retain the face seal or O-ring  62 ′ and prevent the O-ring from escaping from the sleeve slot  56 ′ during the forward and rearward movement of the sleeve  52 ′ relative to the O-ring  62 ′. As also discussed above, when the pressure is applied to the tool  10 ′, the pressure also cooperates with the knob  120 ′, cylindrical sleeve  52 ′ and the container C to force the O-ring  62 ′ against the container C and further improve the seal therebetween. 
     As with the embodiment of  FIGS. 1  A- 8 , the preferred testing tool  10 ′ further includes a plurality of O-rings  94 ′ or the like positioned throughout the actuator unit  12 ′ and the head  40 ′. These O-rings  94 ′ function as seals for the actuation of the internal parts of the tool  10 ′ and their placement and usage will be apparent to one of ordinary skill in the art. 
     Although only a container is illustrated, it will be appreciated that the hydrostatic testing tool can be used to test other various test articles having a threaded aperture, such as a hose or the like. 
     Although the preferred embodiments of the present invention have been described herein, the above description is merely illustrative. Further modification of the invention herein disclosed will occur to those skilled in the respective arts and all such modifications are deemed to be within the scope of the invention as defined by the appended claims.