Abstract:
The test fixture of the present invention comprises a pair of clamping bars/jaws, matched to accommodate an inflation port, or a pressure supply/sensing nozzle. The clamping jaws further comprise a layer of leak proof crushable material, for helping retain the item being tested. When the jaws are activated, the jaws and leak proof crushable material serve to effectively seal the package on the remaining side, and about the pressure supply/sensing nozzle.

Description:
FIELD OF THE INVENTION 
   The present invention is directed to a method and apparatus for testing seal integrity in open packages; and more particularly to a non-destructive method and apparatus for testing seal integrity in open packages. 
   BACKGROUND 
   There are numerous methods and devices in use to ensure the integrity of packaged goods such as sterile medical packages, pharmaceuticals, or food. Moreover, numerous methods for testing the integrity of the packages are known, and relate directly to the packaging in which a product is housed. For example, testing of products packaged in non-flexible containers employ procedures which do not apply to testing of products in flexible containers. Furthermore, the majority of testing methods are destructive, and leave the tested flexible containers in non-serviceable condition. 
   Methods and devices for testing the integrity of seals on packages are known. One such method and device is the apparatus and process for inspecting sealed packages described in U.S. Pat. No. 6,105,419. The device provides an apparatus for inspecting sealed packages of product, and requires a conveyor belt for receiving the packages. An inspection belt contacts the packages and moves away from the conveyor belt a particular distance depending on whether the packages are properly sealed. When engaged by a package with a good seal, the inspection belt is moved a first distance which causes an indicator carried thereon to send a signal which prevents removal of the good package from the conveyor belt. However, when a leaky bag contacts the inspection belt, the inspection belt is moved a second distance which is insufficient to cause the indicator to send a signal. Consequently, the improperly sealed package is removed from the conveyor belt. The inspection belt may be mounted for linear or pivotal movement upon being contacted by the packages carried by the conveyor belt. In addition, a package engaging member can be used to press the packages prior to passing under the inspection belt to facilitate the discharge of air from leaky packages. 
   While the above method provides a method of testing seals on packages, the method requires a conveyer belt and the package engaging member may actually damage the package. Additionally, this method does not provide quantitative data regarding leakage. 
   Another method for leak testing and leak testing apparatus is described in U.S. Pat. No. 6,202,477. The device serves to leak test closed containers which are filled with a filling product containing at least one liquid component. The container is introduced in a test cavity which is evacuated at least down to vapor pressure of that liquid component. The pressure in the surrounding of the container and thus within test cavity is monitored. Monitoring is performed by a vacuum pressure sensor, whereas lowering pressure surrounding the container is performed by a vacuum pump. Leakage is detected by monitoring a pressure change in the surrounding of the container which is due to evaporation of liquid emerging from a leak and being evaporated in the low pressure surrounding. 
   While the above method and apparatus serve to leak test packages, the packages are already sealed on all sides. Additionally an extremely complex apparatus is necessary to perform the testing. 
   Furthermore, safety is an important issue in the operation of pneumatic devices. Because of the forces generated by many of the testing devices, it is essential to develop a test apparatus and method that assures that the operator&#39;s extremities, such as hands or fingers, do not become trapped within the testing apparatus. 
   What is needed in the art is a leak testing apparatus for packages that is non-destructive to the packages under test. 
   Furthermore, what is needed in the art is a leak testing apparatus that provides features that assure that the operator does not sustain injury while performing testing. 
   SUMMARY OF THE INVENTION 
   The present invention provides a non-destructive pneumatically actuated test fixture and method for creating a temporary leak proof seal, on a package that is permanently sealed on the three other sides, to test for leakage using positive pressure. Additionally, the present invention comprises safety measures that assure the operator&#39;s fingers are not caught in the apparatus. 
   The test fixture comprises a pair of clamping jaws, matched to accommodate an inflation port, or a pressure supply/sensing nozzle. The clamping jaws further comprise a layer of leak proof crushable material, for helping retain the item being tested. When the jaws are pneumatically, mechanically, or electrically activated, they close upon the open side of the package under test, and the aforementioned leak proof crushable material serves to effectively seal the package on the remaining side and about the pressure supply/sensing nozzle. The damming effect caused by the crushing of the sealing material precludes gas from escaping from the open side of the package. 
   Additionally, actuation of the pneumatic cylinders or other force generating apparatus allows the operator to conduct high or low pressure leak or seal strength testing. At the completion of the test, the package is released from the fixture by actuating the release actuator, which relieves the clamping force and opens the clamping mechanism. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become appreciated and be more readily understood by reference to the following detailed description of one embodiment of the invention in conjunction with the accompanying drawing, wherein: 
       FIG. 1  is a front isometric view of the open package test fixture of the present invention. 
       FIG. 2  is a rear isometric view of the open package test fixture of the present invention. 
   

   DETAILED DESCRIPTION 
   Referring to  FIG. 1 , a front isometric view of the open package test fixture  10  of the present invention is shown. The test fixture comprises a test fixture body  11 , having an upper clamping jaw  12  and a lower clamping jaw  13 . The clamping jaws are machine matched to accommodate the inflation port&#39;s narrow, knife-edged profile. Additionally the fixture comprises a pressure supply/sensing nozzle  14  located between the upper clamping jaw  12  and lower clamping jaw  13 . Furthermore, both the upper clamping jaw  12  and the lower clamping jaw  13  comprise face regions. The upper clamping jaw  12  comprises an upper clamping jaw face region  15 , and the lower clamping jaw comprises lower clamping jaw face region  16 . The upper and lower clamping jaw face regions  15 ,  16  are each covered with a leak proof crushable material  15   a  and  16   a  respectively. The leak proof crushable material of  15   a  and  16   a  each have a sufficient coefficient of friction to hold the package during testing, prevent slippage, and form a back seal against the open end of the package being tested. The pressure supply/sensing nozzle  14  located between the upper clamping bar  12  and lower clamping bar  13  is adapted to receive the package being tested. 
   In operation, placing the package mouth in the center of the crushable material causes the material to form a unified seal behind, and along the sides of the open end of the package. Any gas that would escape from the open mouth of the package will be effectively stopped by the damming effect caused by the crushing of the sealing material. 
   Furthermore, the upper clamping jaw  12  has an upper clamping jaw mating surface  21  and the lower clamping jaw  13  has a lower clamping jaw mating surface  22 . The upper clamping jaw mating surface  21  and lower clamping jaw mating surface  22  are positioned to accommodate the pressure supply/sensing nozzle  14  located there between. 
   Referring now to  FIG. 2  a rear isometric view of the open package test fixture of the present invention is shown. The pressure supply/sensing nozzle  14  is positioned using a precision nozzle orientation guide  27  such that said pressure supply/sensing nozzle  14  is suspended between the open clamping jaws. This allows placement of the package under test about the pressure supply/sensing nozzle  14  and between the upper and lower clamping jaws. The precision nozzle orientation guide  27  maintains proper alignment of the pressure supply/sensing nozzle  14  with respect to the mating surfaces of the upper and lower clamping jaws. 
   Referring again to  FIG. 1 , once the package is properly placed in the fixture, a user may conduct high or low pressure leak or seal strength testing on a large variety of packages. Additional embodiments are contemplated wherein the fixture can be scaled to accommodate larger packages by adding additional pneumatic cylinders or mechanical actuators, and increasing the width of the fixture. 
   At the completion of the test, the package is released from the fixture by actuating the release mechanism  20 . This release mechanism  20  serves to relieve the clamping force and open the clamping mechanism. 
   Due to the tremendous forces involved with the actuation of the pneumatic cylinders  19  or other types of mechanical actuation, there is a concern for the safety of the operator who is possibly subject to crushing injuries. This safety issue is addressed by utilizing an anti-tie down, two handed actuation system. The test fixture comprises a unique pneumatic circuit, used to allow a latching of the pneumatic force cylinders  19  during testing. The user can actuate the clamping device and walk away without need for manual contact. Referring to the  FIG. 1 , the first and second anti-tie down safety actuators  17  and  18  respectively are shown. The fixture plate body  11  further comprises a fixture plate base  23 . The fixture plate base  23  has a first side  24  and a second side  25 , wherein said upper clamping jaw  12  and said lower clamping jaw  13  are located between said first side of said fixture plate body and said second side of said fixture plate body  11 . Furthermore, the first anti-tie down safety actuator  17  is located proximate to said first side  24  of said fixture base plate  23  and said second anti-tie down safety actuator  18  is located proximate to said second side  25  of said fixture base plate  23 . To actuate said test fixture the operator is required to depress each of the aforementioned actuators simultaneously, thereby precluding the operator from inadvertently catching his fingers between the clamping jaws. 
   Additionally, a barrier  26  is included to prevent the user from inadvertently placing fingers between the clamping jaws during actuation. 
   Furthermore, the fixture is designed to accommodate a restraining plate apparatus that mates to the front of the fixture and provides the ability to conduct restrained testing of the package. 
   While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the present invention using the general principles disclosed herein.