Bellows valve for vacuum systems
A valve for use within a vacuum cup of a vacuum gripping system is described. In one example, a vacuum cup includes a bellows and a valve assembly seated within an inner chamber of the bellows. The valve assembly includes a body disk seated within the inner chamber, a control disk seated toward a suction cup end of the bellows, a spring positioned between the body disk and the control disk, and a control stem extending through the central valve aperture of the body disk, through the spring, and secured to the control disk. When the control stem is seated within the central valve aperture, the valve assembly restricts fluid suction to within the inner chamber. When the valve control stem is unseated from the central valve aperture, the valve assembly conveys fluid suction to the suction cup end of the bellows.
1. A vacuum cup, comprising:
a suction stem tube;
a bellows fitted to an end of the suction stem tube, the bellows comprising a suction cup and at least one compressible pleated convolution, an inner chamber being formed within the bellows; and
a valve assembly seated within the inner chamber, the valve assembly comprising:
a valve body disk seated within the inner chamber and comprising a central valve aperture;
a valve control disk seated between the suction cup and the at least one compressible pleated convolution of the bellows, the valve control disk comprising at least one aperture to convey fluid suction based on a vacuum through the suction stem tube when the valve assembly is open;
a valve spring between the valve body disk and the valve control disk; and
a valve control stem extending through the central valve aperture of the valve body disk, through the valve spring, and secured to the valve control disk.
2. The vacuum cup according to claim 1 , wherein:
the central valve aperture of the valve body disk comprises a tapered central valve aperture;
the valve control stem comprises a tapered valve stop; and
the valve spring pushes the valve body disk apart from the valve control disk within the bellows, to seat the tapered valve stop of the valve control stem into the tapered central valve aperture of the valve control disk and close the valve assembly.
3. The vacuum cup according to claim 2 , wherein:
based on the vacuum through the suction stem tube, a region of low pressure is maintained within the inner chamber between the valve body disk and the suction stem tube when the tapered valve stop of the valve control stem is seated into the tapered central valve aperture of the valve control disk.
4. The vacuum cup according to claim 2 , wherein:
compression of the bellows moves the valve body disk toward the valve control disk, compressing the valve spring, within the bellows, to unseat the tapered valve stop of the valve control stem from the tapered central valve aperture of the valve control disk and open the valve assembly.
5. The vacuum cup according to claim 1 , wherein the valve assembly further comprises:
a plurality of control disk backstops to maintain a predefined minimal mechanical interference distance, at a predefined angular orientation, between the valve body disk and the valve control disk during compression of the bellows.
6. A vacuum cup, comprising:
a suction stem tube;
a bellows fitted to an end of the suction stem tube, the bellows comprising a suction cup and at least one compressible pleated convolution, an inner chamber being formed within the bellows; and
a valve assembly seated within the inner chamber, the valve assembly comprising:
a valve body disk seated within the inner chamber and comprising a central valve aperture; and
a valve control stem extending through the central valve aperture of the valve body disk.
7. The vacuum cup according to claim 6 , wherein the valve assembly further comprises:
a valve control disk seated between the suction cup and the at least one compressible pleated convolution of the bellows, the valve control disk comprising at least one aperture to convey fluid suction based on a vacuum through the suction stem tube when the valve assembly is open.
8. The vacuum cup according to claim 7 , wherein the valve assembly further comprises:
at least one control disk backstop to maintain a predefined minimal mechanical interference distance between the valve body disk and the valve control disk during compression of the bellows.
9. The vacuum cup according to claim 7 , wherein the valve assembly further comprises:
a plurality of control disk backstops to maintain a predefined minimal mechanical interference distance, at a predefined angular orientation, between the valve body disk and the valve control disk during compression of the bellows.
10. The vacuum cup according to claim 7 , wherein:
the valve assembly further comprises a valve spring between the valve body disk and the valve control disk; and
the valve control stem extends through the central valve aperture of the valve body disk, through the valve spring, and is secured to the valve control disk.
11. The vacuum cup according to claim 10 , wherein:
the central valve aperture of the valve body disk comprises a tapered central valve aperture; and
the valve control stem comprises a tapered valve stop.
12. The vacuum cup according to claim 11 , wherein:
the valve spring pushes the valve body disk apart from the valve control disk within the bellows, to seat the tapered valve stop of the valve control stem into the tapered central valve aperture of the valve control disk and close the valve assembly.
13. The vacuum cup according to claim 12 , wherein:
based on the vacuum through the suction stem tube, a region of low pressure is maintained within the inner chamber between the valve body disk and the suction stem tube when the tapered valve stop of the valve control stem is seated into the tapered central valve aperture of the valve control disk.
14. The vacuum cup according to claim 12 , wherein:
compression of the bellows moves the valve body disk toward the valve control disk, compressing the valve spring, within the bellows, to unseat the tapered valve stop of the valve control stem from the tapered central valve aperture of the valve control disk and open the valve assembly.
15. A method of detecting adhesion using a vacuum system, comprising:
starting a vacuum of the vacuum system;
monitoring pressure at a location in an end tool of the vacuum system after starting the vacuum, based on a signal from a pressure sensor in the end tool;
determining that the pressure in the end tool reaches an equilibrium low pressure state;
repositioning the end tool of the vacuum system to initiate a pick of an item; and
identifying a change in the pressure from the equilibrium low pressure state for a period of time based on the signal from the pressure sensor.
16. The method according to claim 15 , further comprising:
after identifying the change in the pressure from the equilibrium low pressure state, repositioning the end tool to move the item; and
stopping the vacuum of the vacuum system to drop the item.
17. The method according to claim 15 , wherein:
the end tool of the vacuum system comprises a vacuum cup; and
the vacuum cup comprises a bellows and a valve assembly seated within the bellows.
18. The method according to claim 17 , wherein the valve assembly comprises:
a valve body disk comprising a central valve aperture;
a valve control disk comprising at least one aperture to convey fluid suction;
a valve spring between the valve body disk and the valve control disk; and
a valve control stem extending through the central valve aperture of the valve body disk, through the valve spring, and secured to the valve control disk.
19. The method according to claim 18 , wherein:
the central valve aperture of the valve body disk comprises a tapered central valve aperture; and
the valve control stem comprises a tapered valve stop.
20. The method according to claim 19 , wherein:
the valve spring pushes the valve body disk apart from the valve control disk within the bellows, to seat the tapered valve stop of the valve control stem into the tapered central valve aperture of the valve control disk and close the valve assembly; and
compression of the bellows moves the valve body disk toward the valve control disk, compressing the valve spring, within the bellows, to unseat the tapered valve stop of the valve control stem from the tapered central valve aperture of the valve control disk and open the valve assembly.