BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic representation of a high pressure fluid cleaning system in accordance with one embodiment of the present invention;
FIG. 2 is a perspective view of a two-way shuttle valve illustrated schematically in FIG. 1;
FIG. 3 is a top sectional view of the shuttle valve shown in FIG. 2;
FIG. 4 is a detailed sectional view of a portion of the valve shown in FIG. 3;
FIG. 5 is a perspective view of a rotary union illustrated schematically in FIG. 1; and
FIG. 6 is a sectional view of the rotary union illustrated in FIG. 5, having a nozzle attached thereto.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a fluid cleaning system in accordance with one embodiment of the present invention. As discussed above, cleaning systems in accordance with the present invention, for example the cleaning system 10, can be used to clean dirt and debris from objects, and in some embodiments, may be used to clean burrs or other surface irregularities from an object, such as a manufacturing workpiece. The system 10 is configured to provide a high pressure fluid stream 11, which, in the embodiment shown in FIG. 1, is water. It is understood, however, that other types of fluids, water and non-water based, can be used with the present invention. The fluid source for the system 10 is a water tank 12, shown in FIG. 1. The tank 12 provides water to a pump 13, which has an inlet 14 for receiving water from the tank 12, and an outlet 15 to provide water at an increased pressure to a valve 16.
The valve 16 is a two-way shuttle valve that can be operated to selectively provide water to a rotating union 18, or alternatively, back to the tank 12. By providing a mechanism for the water to be transferred back to the tank 12, water flow to the union 18 can be stopped without turning off the pump 13, and without creating undesirably high stresses in the system 10, which may occur if the pump 13 is operating and the flow of water is stopped.
The union 18 is attached to an articulating apparatus, which in the embodiment shown in FIG. 1, is a robot arm 20. The robot arm 20 is part of a programmable robot 22, of the type frequently used in industrial and other manufacturing settings. Attached to the union 18 is a nozzle 24 that receives the water through the union 18, and outputs the water through a nozzle outlet 26. As shown in FIG. 6 and described below, the nozzle 24 includes two nozzle outlets, 26, 26′, though for illustrative purposes, the schematic drawing of FIG. 1 shows only the outlet 26. The high pressure stream of water 11 exits the nozzle 24 through the nozzle outlet 26, and contacts an object to be cleaned, such as workpiece 28. Although FIG. 1 shows a single stream of water 11 exiting the nozzle 24, it is understood that a nozzle, such as the nozzle 24, may have multiple nozzle outlets, thereby generating multiple fluid streams. As discussed above, such nozzle outlets can include one or more nozzle outlets radially oriented around the circumference of a nozzle, including one or more nozzle outlets at different locations along the length of a nozzle. In addition, or as an alternative, a nozzle can include an axially oriented outlet.
FIG. 2 shows a perspective view of the valve 16, which is illustrated schematically in FIG. 1. The valve 16 includes a valve body 30 and an actuator 32 mounted externally to the valve body 30. In the embodiment shown in FIG. 2, the actuator 32 is a pneumatic linear actuator, although other types of actuators may be used in accordance with the present invention. For example, hydraulic, mechanical, or electromechanical actuators, such as solenoids, can be used. By externally mounting the actuator 32 on the valve body 30, an advantage is gained through the use of linkages 34, 36. Having actuators that are mounted internally to a valve requires a large valve body, and may also limit or preclude the use of mechanical advantage devices, such as the linkages 34, 36. The linkages 34, 36 pivot about pivot points 38, 40, and therefore, act as a lever to increase the force output by the actuator 32. This allows the actuator 32 to be kept to a relatively small size, while still providing an adequate force to actuate the internal mechanisms of the valve 16.
One end 42 of the linkage 34 acts on a connecting rod 44, while one end 46 of the linkage 36 acts on a connecting rod 48. As described in more detail below, the connecting rods 44, 48 facilitate movement of a piston within the valve body 30. The valve 16 also includes a mounting bracket 50, and a valve inlet 52, which is configured to communicate with a pump, such as the pump 13 shown in FIG. 1. In addition to the inlet 52, the valve 16 includes two valve outlets 54, 56, shown in FIG. 3. FIG. 3 is a top sectional view of the valve 16. As shown in FIG. 3, the connecting rods 44, 48 are connected to a piston 58 disposed within the valve body 30. The valve body 30 includes two channels 60, 62, which respectively provide a portion of a fluid path between the inlet 52 and the outlets 54, 56. Details of the piston 58 are shown in FIG. 4, which provides a closeup view of Detail A indicated in FIG. 3.
As shown in FIG. 4, the piston 58 includes two piston heads 64, 66. Each of the piston heads 64, 66 includes a respective first surface 67, 69 that is disposed proximate the valve inlet 52, such that fluid entering the valve inlet 52 exerts a force against the first surfaces 67, 69. As described below, one of the advantages of the valve 16 is that it is configured to reduce or eliminate impact on the piston heads 64, 66 that would otherwise result from the high forces generated by the inlet fluid.
Each of the piston heads 64, 66 is configured to cooperate with a respective valve seat 68, 70. In particular, a tapered portion 72, 74 of the piston heads 64, 66 is configured to mate with corresponding tapered portions 76, 78 of the valve seats 68, 70. In order to provide a path for fluid to flow from the inlet 52 to either of the outlets 54, 56—see FIG. 3—fluid passages are provided through the piston heads 64, 66. For example, as shown in FIG. 4, fluid passages 80, 82 traverse the piston head 64. In a first position as shown in FIG. 4, no fluid flows from the inlet 52 into the channel 60, because the piston head 64 is securely mated with the valve seat 68. It is understood that fluid passages also exist in the piston head 66, but are oriented at approximately 90 degrees from the passages 80, 82, and are therefore not visible in FIG. 4. It is through such passages, however, that fluid will flow from the inlet 52 through the piston head 66, and into the channel 62.
As described above, the valve 16 is configured to reduce the impact seen by the piston 58, and in particular, seen by the piston heads 64, 66, that would otherwise result from the high forces generated by the high pressure fluid entering the inlet 52. As shown in FIG. 4, the piston head 64 includes an elongate portion, or nose 84, that is configured to cooperate with the channel 60. Specifically, the outside diameter of the nose 84 is only slightly smaller than the inside diameter of the channel 60. Similarly, the piston head 66 includes an elongate portion, or nose 86, which is configured to cooperate with the channel 62. Starting with the piston 58 in the first position shown in FIG. 4, the actuator 32—see FIG. 2—can be operated to move the piston 58 to the left into a second position to open the channel 60, and close the channel 62. In the second position, the piston head 66 securely mates with the valve seat 70.
As the actuator 32 begins to move the piston and fluid begins to flow into the channel 60, the high pressure fluid entering the inlet 52 will have a tendency to act on the surface 69 of the piston head 66, thereby forcing it to the left. The effect of this force is mitigated, however, as the nose 86 begins to enter the channel 62, thereby constricting the amount of fluid that can flow back through the piston head 66 from the channel 62. The fluid in the channel 62 must be pushed forward, and this provides a reaction force to dampen movement of the piston 58 toward the valve seat 70. This configuration reduces or eliminates the impact seen by the piston heads 64, 66, thereby increasing the longevity of the valve 16.
FIG. 5 shows an isometric view of the rotary union 18, which is illustrated schematically in FIG. 1. The union 18 includes a first portion 88, and a second portion 90 that is configured to rotate within the first portion 88. The union 18 includes a fluid inlet 92 that is configured to receive fluid from the valve 16 through one of the valve outlets 54, 56. The union 18 also includes a fluid outlet 94, which, as described below, is configured to receive a nozzle, such as the nozzle 24 shown in FIG. 1. The second portion 90 of the union 18 includes a mounting structure 96 which, in the embodiment shown in FIG. 5, has a mounting face 98 configured with a plurality of threaded holes 100 to facilitate attachment of the union 18 to an articulating apparatus, such as the robot arm 20 shown in FIG. 1.
In addition to the threaded holes 100, the mounting face 98 includes a first locating feature, which in the embodiment shown in FIG. 5, is an aperture 102. The aperture 102 is configured to receive a pin or other fastener that will align the mounting face 98 with a portion of the robot arm 20 so that there is a known radial orientation between the position of the robot arm 20 and the second portion 90 of the union 18. The mounting face 98 also includes a coaxial locating feature, which, in the embodiment shown in FIG. 5, is a circular boss 103. Of course, other types of coaxial locating features may be used, for example, locating pins. The boss 103 is configured to cooperate with a recess in the robot arm 20 so that there is known axial orientation in two orthogonal directions between the position of the robot arm 20 and the union 18. The boss 103 effectively centers the second portion 90 of the union 18 on the robot arm 20.
In addition to the first locating feature 102, and the boss 103, the union 18 also includes a second locating feature 104, shown in FIG. 6. FIG. 6 is a sectional view of the union 18 having the nozzle 24 attached thereto. Although illustrated schematically in FIG. 1 with a single nozzle outlet 26, the detailed view of FIG. 6 shows that the nozzle 24 includes two nozzle outlets 26, 26′. The second locating feature 104 is positioned at a predetermined radial orientation relative to the first locating feature 102, thereby providing a known radial orientation between the robot arm 20 and the second locating feature 104. As described below, this facilitates proper positioning of the nozzle 24 relative to the workpiece 28—see FIG. 1.
As shown in FIG. 6, the second locating feature 104 forms an elongate member that is configured to cooperate with a locating feature, or recessed portion 106, in the nozzle 24. The recessed portion 106 is disposed at a predetermined radial location relative to the nozzle outlets 26, 26′. Therefore, the robot 22 can be programmed to accurately position the nozzle outlets 26, 26′ so that the fluid stream 11 contacts the workpiece 28 at the desired location—see FIG. 1. In summary, the robot 22 is programmed to know the position of the robot arm 20. The robot arm 20 is attached to the union 18 with a known radial orientation because of the first locating feature 102. The nozzle 24 can be attached in only one position to the union 18—i.e., the nozzle 24 is keyed to the union 18—because of the cooperation between the recessed portion 106 and the second locating feature 104. Finally, the nozzle outlets 26, 26′ have a known radial orientation to the recessed portion 106, which provides known positioning from the nozzle outlets 26, 26′ back through the union 18 to the robot arm 20 so that the robot 22 can appropriately position the nozzle 24.
In the embodiment shown in FIG. 6, the nozzle 24 is made up of two members 107, 108, each of which has been shortened in the drawing figure for illustrative purposes. The nozzle 24 is held in place by a retaining nut 110 that cooperates with threads 111 on the second portion 90 of the union 18. As shown in FIG. 6, the second portion 90 includes a generally cylindrical portion 112 that is disposed within the first portion 88. O-ring seals 113 are used to keep fluid from leaking out of the union 18. In addition, because the second portion 90 rotates within the first portion 88, friction washers 114, 116 are disposed between the two portions 88, 90. A retainer 118 is held in place with a snap ring 119, and keeps the two portions 88, 90 together.
To facilitate fluid flow through the union 18, the second portion 90 has a number of apertures disposed therethrough. For example, a transverse aperture 120 is disposed through the second portion 90, and connects with an axial aperture 122 to provide an outlet path for the fluid. In order to ensure that the union 18 can accommodate a desired amount of fluid flow, a second transverse aperture, such as the aperture 124, may be provided. In addition, the second portion 90 of the union 18 includes an annular groove 126 that communicates with the transverse apertures 120, 124. This helps to ensure uninterrupted fluid flow as the second portion 90 rotates into positions where neither of the transverse apertures 120, 124 are directly aligned with the fluid inlet 92. Of course, other embodiments may use more or less than two of the transverse apertures to achieve the desired fluid flow. In some embodiments, the second port 90 may rotate at approximately 80 revolutions per minute (rpm), and the groove 126 helps to ensure adequate fluid flow regardless of the speed or position of the second portion 90 relative to the first portion 88.
While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.
Patent Application
20080053495
