Abstract
A bellows-cup vacuum gripping tool comprising one tool-change interface, one bellows cup, one vacuum pump, one isolation valve and one vent valve. When the bellows cup reaches the workpiece, the bellows cup is evacuated by the vacuum pump. 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 bellows-cup vacuum gripping tool: one bellows cup carried on a tool-change interface, fed by a vacuum pump. It is arranged for cutting part of the circuit while the rest holds vacuum, controlling the moment of release, taking up height differences at the face and exchanging the tool without rewiring the cell. 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 tool-change interface. The tool-change interface splits the tool into a robot side and a tool side, so the tool can be exchanged without dismantling it. The tool-change interface has a pneumatic lock.
[0003]One bellows cup. Each bellows cup is folded so that it shortens under vacuum and takes up a height difference between the face and the workpiece. Each bellows cup has two folds.
[0004]One vacuum pump. The pump draws the circuit down mechanically and adds its own mass to the moving assembly.
[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 bellows cup is carried on the tool side of the tool-change interface.
[0008]The vacuum pump is fixed to the tool side of the tool-change interface.
[0009]The isolation valve is placed in the line from the vacuum pump, so that closing the valve cuts the whole circuit from the supply.
[0010]The bellows cup 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 tool-change interface is bolted to the robot flange.
[0013]The pump motor is supplied from the electrical supply of the cell.
[0014]The locking piston of the tool-change interface is fed from the compressed air supply of the cell.
[0015]The isolation valve, the vent valve and the lock of the tool-change interface are switched by the cell controller.
3. Operating sequence and conditions
[0016]
- When the bellows cup reaches the workpiece, the bellows cup is evacuated by the vacuum pump.
[0017]
- After the bellows cup has reached the workpiece, the isolation valve is closed by the cell controller.
[0018]
- While the isolation valve is in the closed state, the vacuum downstream of the valve is maintained by the sealed gripping face.
[0019]
- After the workpiece has reached the set-down position, the vacuum circuit is vented by the vent valve.
[0020]
- The workpiece is held until the vent valve has opened the circuit.
[0021]The cell controller commands the isolation valve, the tool-change interface, the vent valve; no sensor drives an actuator directly.
4. Parameters and operating assumptions
[0022]Parameter values of this embodiment: locking of the tool-change interface: pneumatic (sets what has to be present at the interface for the tool to stay attached); folds of the bellows cup: two (sets the travel taken up between the face and the workpiece, and the lateral stiffness of the cup under load); material of the bellows cup: plastic (sets the friction at the lip and the resistance of the folds to fatigue); drive medium of the vacuum pump: electric (sets the supply the pump motor needs from the cell); 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).
[0023]The lock is engaged by compressed air acting on the locking piston and is held only while that air pressure is applied; what the lock does on loss of air pressure is not fixed by this arrangement.
5. Provenance and status
[0024]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-4489564-B1, US-10163334-B1, US-11427405-B1, US-11858125-B2, WO-2008134339-A4; their text is not reproduced, and the description above is generated from the structure of the combination.