Abstract
A suction-cup vacuum gripping tool comprising one tool-change interface, four suction cups, one vacuum pump, one manifold, one pressure sensor and one vent valve. When the suction cups reach the workpiece, the suction cups 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 suction-cup vacuum gripping tool: four suction cups carried on a tool-change interface, fed by a vacuum pump. It is arranged for verifying that the workpiece is held before the arm moves, controlling the moment of release 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 suction cups. Each suction cup presents a sealing lip to the workpiece and is evacuated through its own connection. The count of four follows from the arrangement: one gripping element per manifold outlet. The suction cups are of the oval form.
[0004]One vacuum pump. The pump draws the circuit down mechanically and adds its own mass to the moving assembly.
[0005]One manifold. The manifold receives the vacuum at one inlet and distributes it to its outlets. The manifold has four outlets.
[0006]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.
[0007]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.
[0008]The suction cups are carried on the tool side of the tool-change interface.
[0009]The manifold is fixed to the tool side of the tool-change interface.
[0010]The vacuum pump is fixed to the tool side of the tool-change interface.
[0011]The manifold inlet is connected to the pump inlet line, which supplies every outlet of the manifold.
[0012]Each manifold outlet feeds one suction cup by its own vacuum line, so that the four outlets feed four suction cups.
[0013]The pressure sensor is tapped into the line between the vacuum pump and the distribution and reads the pressure of the whole circuit.
[0014]The vent valve is connected to the circuit at the pump inlet line and opens that circuit to atmosphere when it is actuated.
[0015]The robot side of the tool-change interface is bolted to the robot flange.
[0016]The pump motor is supplied from the electrical supply of the cell.
[0017]The vent valve is switched by the cell controller; the pressure sensor reports to the cell controller.
3. Operating sequence and conditions
[0018]
- When the suction cups reach the workpiece, the suction cups are evacuated by the vacuum pump.
[0019]
- When the vacuum level exceeds the gripping threshold, a secure grip is signalled by the pressure sensor.
[0020]
- The workpiece may not be lifted unless the pressure sensor signals a secure grip.
[0021]
- After the workpiece has reached the set-down position, the vacuum circuit is vented by the vent valve.
[0022]
- The workpiece is held until the vent valve has opened the circuit.
[0023]The cell controller reads the pressure sensor (the common supply line) and commands the vent valve; no sensor drives an actuator directly.
4. Parameters and operating assumptions
[0024]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); form of the suction cups: oval (sets the shape of the contact area and the behaviour of the lip on a curved workpiece); material of the suction cups: polyurethane (sets the friction at the lip and the tolerance of the lip to oil and heat); drive medium of the vacuum pump: electric (sets the supply the pump motor needs from the cell); 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).
[0025]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.
[0026]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
[0027]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 US-11427405-B1, US-11858125-B2, US-2016214812-A1, US-8006968-B2, WO-2008134339-A4; their text is not reproduced, and the description above is generated from the structure of the combination.