Abstract
A foam-pad vacuum gripping tool comprising one tool-change interface, four foam pads, one vacuum pump, one isolation valve, one manifold, one pressure sensor and one vent valve. When the foam pads reach the workpiece, the foam pads are 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 foam-pad vacuum gripping tool: four foam pads 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, verifying that the workpiece is held before the arm moves, controlling the moment of release, holding a workpiece that a rigid lip cannot seal against 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 mechanical lock.
[0003]Four foam pads. Each 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 count of four follows from the arrangement: one gripping element per manifold outlet. The pad is of closed cell foam.
[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 manifold. The manifold receives the vacuum at one inlet and distributes it to its outlets. The manifold has four outlets.
[0007]One pressure sensor. The pressure sensor taps the line it is placed in and reports the vacuum level in that line. The pressure is measured in the supply line.
[0008]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.
[0009]The foam pads are carried on the tool side of the tool-change interface.
[0010]The manifold is fixed to the tool side of the tool-change interface.
[0011]The vacuum pump is fixed to the tool side of the tool-change interface.
[0012]The isolation valve is placed in the line from the vacuum pump, so that closing the valve cuts the whole circuit from the supply.
[0013]The manifold inlet is connected to the isolation valve outlet, which supplies every outlet of the manifold.
[0014]Each manifold outlet feeds one foam pad by its own vacuum line, so that the four outlets feed four foam pads.
[0015]The pressure sensor is tapped into the line between the vacuum pump and the distribution and reads the pressure of the whole circuit.
[0016]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.
[0017]The robot side of the tool-change interface is bolted to the robot flange.
[0018]The pump motor is supplied from the electrical supply of the cell.
[0019]The isolation valve and the vent valve are switched by the cell controller; the pressure sensor reports to the cell controller.
3. Operating sequence and conditions
[0020]
- When the foam pads reach the workpiece, the foam pads are evacuated by the vacuum pump.
[0021]
- When the vacuum level exceeds the gripping threshold, a secure grip is signalled by the pressure sensor.
[0022]
- The workpiece may not be lifted unless the pressure sensor signals a secure grip.
[0023]
- After the vacuum level has exceeded the gripping threshold, the isolation valve is closed by the cell controller.
[0024]
- While the isolation valve is in the closed state, the vacuum downstream of the valve is maintained by the sealed gripping face.
[0025]
- After the workpiece has reached the set-down position, the vacuum circuit is vented by the vent valve.
[0026]
- The workpiece is held until the vent valve has opened the circuit.
[0027]The cell controller reads the pressure sensor (the common supply line) and commands the isolation valve, the vent valve; no sensor drives an actuator directly.
4. Parameters and operating assumptions
[0028]Parameter values of this embodiment: locking of the tool-change interface: mechanical (sets what has to be present at the interface for the tool to stay attached); material of the foam pads: sponge (sets the compliance of the sealing face); porosity of the foam pads: closed cell (sets whether air passes through the pad body or only through openings cut through it); 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; outlets of the manifold: four (sets how many lines can be fed from one inlet); placement of the pressure sensor: in the supply line (sets where in the circuit the reading is taken and what it describes); 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).
[0029]The closed-cell foam does not pass air through its body; the face is evacuated through openings cut through the pad into the distribution chamber, and the foam around each opening forms the seal against the workpiece.
[0030]The lock is engaged by a manually operated lever on the interface; no supply crosses the interface for the lock, and tool exchange needs an operator at the tool.
[0031]Vacuum levels are stated as gauge pressure below atmosphere. A stronger vacuum is a larger pressure difference below atmosphere, and the vacuum level 'exceeds the gripping threshold' when that difference is at least the threshold difference.
5. Provenance and status
[0032]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-11427405-B1, US-11858125-B2, US-8006968-B2, WO-2008134339-A4; their text is not reproduced, and the description above is generated from the structure of the combination.