Patent Application
20060236778
1. Field of The Invention
The invention relates to a measuring assembly used to measure the adhesion of ice. More specifically, the measuring assembly is designed to measure the adhesion of ice between coated parts that are designed to move relative to each other.
2. Description of the Related Art
When mechanical components of an assembly are exposed to freezing environment, their function can sometimes deviate from the originally designed intent. This is especially true when two components are exposed to ice. When moisture covering the components freezes, the components may stick together resulting in reduced functionality of those components or other components related to the frozen components.
In most applications, these components are coated with a coating that inhibits corrosion. These coatings may have properties that facilitate the movement of one component relative to another. These coatings enhance the feel of the operation of mechanisms and maintain that feel over a longer period of time. In other words, these coatings reduce friction and prevent corrosion allowing the reduced frictional properties to be maintained over a longer period of time. There is a need to be able to evaluate the performance of these coatings in a freezing environment.
Currently, there is no known test of these coatings to determine whether these coatings will operate when moisture freezes around the components other than building a complete assembly and testing it in a “freezing” environment. Such practice is normally expensive and excessively time consuming. This invention allows for an inexpensive and timely comparison of different coatings. While a coating may have excellent friction reducing properties above freezing temperatures, it may not operate well below freezing temperatures. In an attempt to measure the properties of coatings that are exposed to moisture below freezing temperatures, a testing apparatus needs to be able to isolate variables in the testing procedure so that a coating may be tested precisely controlling several of the variables during the testing procedure.
A measuring assembly measures the adhesion between a fixed part and a movable part wherein the fixed part and movable part have ice extending therebetween. The measuring assembly includes a chamber for maintaining the ice, the fixed part and the movable part at a predetermined temperature. A tension generator applies a force to the movable part to separate the movable part from the fixed part. A tension gauge measures the force required for the movable part to overcome the adhesion to the fixed part that results from the presence of ice.
Advantages of the invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
Referring to
The measuring assembly 10 includes a base 18 and two base extensions 20, 22 extending out therefrom to stabilize the measuring assembly 10 on a lab bench 24. The measuring assembly 10 includes a first tower 26 that is used to position all the operating components of the measuring assembly 10 appropriately. These components will be discussed in greater detail subsequently. The measuring assembly 10 also includes a second tower 28. The second tower 28 houses all of the electronics used to control and operate the measuring assembly 10. It should be appreciated by those skilled in the art that a single housing including the first 26 and second 28 towers could be incorporated into the measuring assembly 10. Further, the second tower 28 could be removed entirely if the control electronics and measuring electronics were mounted to the first tower 26 or even separated completely from the measuring assembly 10 and operatively connected to the measuring assembly 10 through a wireless protocol, such as radio frequency, wireless fidelity, optical and the like.
The measuring assembly 10 includes a chamber 30 that is fixedly secured to the first tower 26. The chamber 30 maintains the ice 16, the fixed part 12 and the movable part 14 at a predetermined temperature. Because the measuring assembly 10 is designed to measure the adhesion of certain coatings with respect to the build up of ice 16, the predetermined temperature in which the chamber 30 is maintained is below freezing. The chamber 30 is rectangular in shape and includes four sides 32, a back side 34, and a removable front cover 35. All interior surfaces of the chamber 30 are insulated with layers of insulation 36.
The chamber 30 also includes a convection fan 38 which circulates the air inside the chamber 30 to maintain the temperature inside the chamber 30 as consistent as possible throughout the interior space of the chamber 30. A temperature sensor 40 extends down into the interior portion of the chamber 30. The temperature sensor 40 is operatively connected to the controls of the measuring assembly 10 through an electrical conductor 42 (shown partially cut away in
Referring to
Referring to
The motor 50 has an output shaft 56 that drives an output pulley 58, which in turn drives a belt 60 to translate the output force of the motor 50 laterally with respect to the motor 50.
Driven by the belt 60 is a drive pulley 62. The drive pulley 62 is fixedly secured to a drive shaft 64. A fly wheel 66 is also fixedly secured to the drive shaft 64 at a location spaced from the drive pulley 62. The flywheel 66 may be used to smooth the operation of the motor 50. In addition, the flywheel can act as a handle to manually rotate the drive shaft 64 should such manual operation be required.
The drive shaft 64 is mounted to the first tower 26 via a lateral extension 68, which is supported by a bracket (not shown). A bearing 70 is fixedly secured to the lateral extension 68 and positions the drive shaft 64 therethrough. A hole (not shown) extends through the lateral extension 68 allowing the drive shaft 64 to extend through the lateral extension 68 and down one side of the first tower 26.
Below the lateral extension 68, the drive shaft 64 includes a threaded portion 72. The threaded portion 72 of the drive shaft 64 acts as a lead screw because the drive shaft 64 does not move axially. It only moves rotationally. A follower 74 threadingly engages the threaded portion 72 whereby rotation of the drive shaft 64 translates into axial movement of the follower 74 up and down the threaded portion 72 of the drive shaft 64. Therefore, the follower 74 translates the rotational movement of the drive shaft 64 and the motor 50 into axial movement 74 along the drive shaft 64 coaxially therewith.
A slide 76 is fixedly secured to the follower 74. The slide 76 has a width that is almost as long as a width of the first tower 26. Two guides 78, 80 are fixedly secured to the first tower 26 and extend vertically and parallel to each other. The guide 78, 80 include mounting portions 82, 84 and engagement portions 86, 88 respectively. In one embodiment, the engagement portions 86, 88 include cylindrical distal ends 90, 92. The slide 76 includes upper 94 and lower 96 guide mounts on either side of the slide 76. The slide 76 and guides 78, 80 facilitate the smooth transition of the slide axially up and down in response to the rotation of the threaded portion 72 of the drive shaft 64. Other mechanisms for guiding the follower are possible.
The slide 76 includes a measuring bracket 98 on one side thereof. The measuring bracket 98 abuts a linear measuring device 100 which is used to accurately identify the position of the slide 76 at any given time. The linear measuring device 100 is fixedly secured to the first tower 26 via a bracket 102.
The slide 76 defines a lower surface 104 which extends perpendicular to each of the guides 78, 80. The lower surface 104 is flat. Three tension gauges 106, 108, 110 are fixedly secured to the lower surface 104 of the slide 76. Three tension gauges 106-110 are used as a matter of convenience allowing the testing of three movable part 14/fixed part 12 combinations at a time. It should be appreciated by those skilled in the art that the measuring assembly 10 can be constructed with the capability of testing only a single movable part 14/fixed part 12 combination. The tension gauges 106-110 measure the force required to overcome the adhesion between the movable part 14 and the ice 16 to remove the movable part 14 from the fixed part 12.
Extending down from each of the gauges 106-110 are three extensions 112, 114, 116. Each of the extensions 112-116 includes an upper portion 118, 120, 122 and a lower portion 124, 126, 128. A universal joint 130, 132, 134 extends between the upper portions 118-122 and the lower portions 124-128, respectively. The universal joints 130-134 provide two degrees of freedom for the lower portions with respect to the upper portions 118-122. This allows for the proper positioning of the movable part 14 with respect to the fixed part 12.
The lower portions 124-128 extend through holes in one of the four sides 32 of the chamber 30. Fixedly secured to each of the lower portions 124-128 are holders 136, 138, 140. The holders removably secure a movable part 14 to the lower portion 124-128 of the extension 112-116. The holders 136-140 will be discussed in greater detail subsequently.
Returning attention to the chamber 30, three reservoirs 142, 144, 146 are generally shown in
The holders 136-140 include a positioning half 164 and a tightening half 166. The movable part 14 is secured therebetween after a bolt 168 forces the tightening half 166 into the positioning half 164. The positioning half 164 includes a lateral positioning stem 170 which will be discussed in greater detail subsequently. The holders 136-140 are fixedly secured to the lower portions 124-128 of the extensions 112-116.
Fixedly secured to a lower portion 172 of the first tower 26 are lateral adjusters 174, 176, 178. The lateral adjusters move the movable part 14 laterally with respect to the fixed part 12 to a predetermined distance. Each of the lateral adjusters includes a micrometer 180, 182, 184 that extends through the first tower 26 and the backside 34 of the chamber 30. Each micrometer 180-184 includes feedback circuitry 186, 188, 190 which provides a signal to the controls allowing manual adjustment of the lateral position of the movable part 14 to ensure that each is positioned appropriately with respect to the fixed part 12. The ends of the micrometers abut the lateral positioning stem 170 of each of the holders 136-140. Each micrometer 180-184 includes a switch (not shown) that disengages the drive mechanism, thereby preventing accidental damage to the device.
Once the movable part 14 is in position with respect to the fixed part 12, water is poured into the reservoirs 142-146. Typically a syringe (not shown) is used to transfer the water to each of the reservoirs 142-146, thus ensuring an accurate amount of water is poured into each of the reservoirs 142-146. The chamber 30 is then closed by securing the front cover 35 to the chamber 30. Liquid nitrogen is then fed through the conduit 44 to cool the chamber 30 to the desired temperature. Once the ice 16 is formed, the micrometers 180-184 are retracted away from the holders 136-140 to prevent damage to the micrometers 180-184. The motor 50 is then started to pull the slide 76 upwardly. This, in turn, pulls the movable parts 14 away from the fixed parts 12. The tension gauges 106-110 measure the force required to remove the movable part 14 from the ice 16 and away from the fixed part 12. These calculations may be used to identify coatings on the fixed part 12 and movable 14 that enhance the ability of the movable part 14 to move with respect to the ice 16 and the fixed part 12. While the invention disclosed shows a lateral configuration wherein the movable part 14 is moved laterally with respect to the fixed part, the measuring assembly 10 may be configured such that the movable part 14 may be moved in a rotational sense with respect to the fixed part.
The invention has been described in an illustrative manner. It is to be understood that the terminology, which has been used, is intended to be in the nature of words of description rather than of limitation.
Many modifications and variations of the invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the invention may be practiced other than as specifically described.
