Abstract
A zoned vacuum gripping tool comprising one tool-change interface, four suction cups, one vacuum pump, four zone branches, four pressure sensors 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 zoned vacuum gripping tool: four suction cups carried on a tool-change interface, fed by a vacuum pump. It is arranged for handling workpieces that do not cover the whole gripping face, 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 zone branch. 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]Four zone branches. Each zone branch carries the vacuum of one zone of the face and no other. The count of four follows from the arrangement: one branch per zone. The distribution is divided into four zones, each fed by its own branch.
[0006]Four pressure sensors. Each pressure sensor taps the line it is placed in and reports the vacuum level in that line. The count of four follows from the arrangement: one sensor per zone branch. The pressure is measured at each zone.
[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 vacuum pump is fixed to the tool side of the tool-change interface.
[0010]The four zone branches are taken from a branch junction on the pump inlet line, so that each branch carries the vacuum of its own zone only.
[0011]Each suction cup is connected to its own zone line, one suction cup per zone, and is evacuated through that line.
[0012]One pressure sensor is tapped into each zone line, so that each of the four sensors reads its own zone and no other.
[0013]The vent valve is connected to the circuit at the pump inlet line and opens that circuit to atmosphere when it is actuated.
[0014]The robot side of the tool-change interface is bolted to the robot flange.
[0015]The pump motor is supplied from the electrical supply of the cell.
[0016]The vent valve is switched by the cell controller; the pressure sensors reports to the cell controller.
3. Operating sequence and conditions
[0017]
- When the suction cups reach the workpiece, the suction cups are evacuated by the vacuum pump.
[0018]
- When the vacuum level exceeds the gripping threshold, a secure grip is signalled by the pressure sensor of each zone in use.
[0019]
- The workpiece may not be lifted unless the pressure sensor of each zone in use signals a secure grip.
[0020]
- After the workpiece has reached the set-down position, the vacuum circuit is vented by the vent valve.
[0021]
- The workpiece is held until the vent valve has opened the circuit.
[0022]The cell controller reads the pressure sensor (each zone line) and commands the vent valve; no sensor drives an actuator directly.
4. Parameters and operating assumptions
[0023]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); material of the zone branches: plastic; zones of the zone branches: four (sets how much of the face can be treated separately); placement of the pressure sensors: at each zone (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).
[0024]A zone is in use when the workpiece covers it. Which zones are in use is decided by the controller from the workpiece programme; this arrangement fixes where each zone is measured, not how the programme is written.
[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, WO-2008134339-A4, WO-2026020244-A1; their text is not reproduced, and the description above is generated from the structure of the combination.
6. Correction notice
[0028]This publication supersedes OT-2026-000004265, whose text described this arrangement with defects recorded in the quality register at https://opentechnical.org/qa/. The earlier publication is unchanged and remains public. Changes made to reach a consistent configuration: release element added: a vent valve after set-down (the legacy assembly had no way to let go).