Abstract
A foam-pad vacuum gripping tool comprising one mounting flange, one foam pad, one ejector, one isolation valve and one vent valve. When the foam pad reaches the workpiece, the foam pad is evacuated by the ejector. After the workpiece has reached the set-down position, the vacuum circuit is vented by the vent valve. The arrangement is a proposed configuration composed from a typed library of mechanism blocks derived from published patents; it has not been constructed.
1. Purpose and arrangement
[0001]This disclosure describes a foam-pad vacuum gripping tool: one foam pad carried on a mounting flange, fed by an ejector. It is arranged for cutting part of the circuit while the rest holds vacuum, controlling the moment of release and holding a workpiece that a rigid lip cannot seal against. One concrete embodiment is described; every connection is stated with the medium it carries, and the operating sequence is given as conditions on named operations.
2. Components, construction and connections
[0002]One mounting flange. The mounting flange carries the whole assembly and presents the bolt pattern that meets the robot.
[0003]One foam pad. The foam pad presents a compliant face to the workpiece; the holding force is spread over the contact area rather than concentrated at a lip. The pad is of open cell foam.
[0004]One ejector. The ejector draws the circuit down by passing compressed air through a nozzle; it has no moving part at the tool and consumes air for as long as it runs. The ejector has one stage.
[0005]One isolation valve. The isolation valve sits in the line it controls; closing it cuts that line without disturbing the rest of the circuit. Isolation is common.
[0006]One vent valve. The vent valve opens the circuit it is connected to towards atmosphere, which ends the grip. The circuit is vented after set-down.
[0007]The foam pad is carried on the tool side of the mounting flange.
[0008]The ejector is fixed to the tool side of the mounting flange.
[0009]The isolation valve is placed in the line from the ejector, so that closing the valve cuts the whole circuit from the supply.
[0010]The foam pad is connected to the isolation valve outlet by a single vacuum line, so that the face is evacuated through that line.
[0011]The vent valve is connected to the circuit at the line downstream of the isolation valve and opens that circuit to atmosphere when it is actuated.
[0012]The robot side of the mounting flange is bolted to the robot flange.
[0013]The ejector is fed from the compressed air supply of the cell.
[0014]The isolation valve and the vent valve are switched by the cell controller.
3. Operating sequence and conditions
[0015]
- When the foam pad reaches the workpiece, the foam pad is evacuated by the ejector.
[0016]
- After the foam pad has reached the workpiece, the isolation valve is closed by the cell controller.
[0017]
- While the isolation valve is in the closed state, the vacuum downstream of the valve is maintained by the sealed gripping face.
[0018]
- After the workpiece has reached the set-down position, the vacuum circuit is vented by the vent valve.
[0019]
- The workpiece is held until the vent valve has opened the circuit.
[0020]The cell controller commands the isolation valve, the vent valve; no sensor drives an actuator directly.
4. Parameters and operating assumptions
[0021]Parameter values of this embodiment: material of the foam pad: sponge (sets the compliance of the sealing face); porosity of the foam pad: open cell (sets whether air passes through the pad body or only through openings cut through it); stages of the ejector: one (sets the flow drawn at low vacuum and the compressed air consumed while a sealed face is held); control of the isolation valve: common (sets which part of the circuit the valve cuts: one branch line on its own or the whole circuit); material of the isolation valve: steel; timing of the vent valve: after set-down (sets whether the workpiece is released before or after it is supported by the set-down surface).
[0022]The open-cell foam passes air through its whole face, so an uncovered part of the face draws air through the pad itself; the supply is sized for that continuous flow and the pad relies on flow restriction through the foam, not on a seal, to hold vacuum behind a covered area.
5. Provenance and status
[0023]This document is an original combination composed from a typed library of mechanism blocks. Each block was derived from a published patent and carries typed connection points, the parameters its source states, and its own construction and operating description. The combination described here is proposed and has not been constructed. The published documents behind the blocks used in this arrangement are EP-4385681-B1, US-10163334-B1, US-10549431-B2, WO-2008134339-A4; their text is not reproduced, and the description above is generated from the structure of the combination.