OPENTECHNICAL PUBLICATION OT-2026-000047751 Foam pad vacuum gripper, two zone face, common isolation valve, plant vacuum fed, pressure sensor per zone, pulsed blow-off before set-down, on a tool changer Published: 2026-09-17T08:33:24.028554Z Permanent URL: https://opentechnical.org/p/OT-2026-000047751 Categories: Robotics & Automation > End Effectors > Vacuum Grippers ------------------------------------------------------------------------ ABSTRACT A zoned vacuum gripping tool comprising one tool-change interface, one foam pad, one plant vacuum connection, one isolation valve, two zone branches, two pressure sensors and one blow-off valve. When the foam pad reaches the workpiece, the foam pad is evacuated by the plant vacuum connection. Before the workpiece reaches the set-down position, the workpiece is blown off by the blow-off valve while the workpiece is above the receiving surface. 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: one foam pad carried on a tool-change interface, fed by a plant vacuum connection. It is arranged for handling workpieces that do not cover the whole gripping face, cutting part of the circuit while the rest holds vacuum, verifying that the workpiece is held before the arm moves, clearing the face at 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] 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 plant vacuum connection. The plant vacuum connection takes vacuum from the plant line, so the tool carries no generator of its own. [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] Two zone branches. Each zone branch carries the vacuum of one zone of the face and no other. The count of two follows from the arrangement: one branch per zone. The distribution is divided into two zones, each fed by its own branch. [0007] Two pressure sensors. Each pressure sensor taps the line it is placed in and reports the vacuum level in that line. The count of two follows from the arrangement: one sensor per zone branch. The pressure is measured at each zone. [0008] One blow-off valve. The blow-off valve drives compressed air back through the circuit to the face, which clears the face instead of waiting for the circuit to refill. The blow-off is a short pulse. The blow-off pulse is given before set-down. [0009] The foam pad is carried on the tool side of the tool-change interface. [0010] The isolation valve is placed in the line from the plant vacuum connection, so that closing the valve cuts the whole circuit from the supply. [0011] The two zone branches are taken from a branch junction on the isolation valve outlet, so that each branch carries the vacuum of its own zone only. [0012] Each zone line opens into its own section of the distribution chamber behind the porous face of the foam pad, so that the pad is evacuated zone by zone. [0013] One pressure sensor is tapped into each zone line, so that each of the two sensors reads its own zone and no other. [0014] The blow-off valve is connected to the circuit at the line downstream of the isolation valve, so that compressed air can be driven back through the circuit to the face. [0015] The robot side of the tool-change interface is bolted to the robot flange. [0016] The blow-off valve is fed from the compressed air supply of the cell. [0017] The isolation valve and the blow-off valve are switched by the cell controller; the pressure sensors reports to the cell controller. 3. Operating sequence and conditions [0018] - When the foam pad reaches the workpiece, the foam pad is evacuated by the plant vacuum connection. [0019] - When the vacuum level exceeds the gripping threshold, a secure grip is signalled by the pressure sensor of each zone in use. [0020] - The workpiece may not be lifted unless the pressure sensor of each zone in use signals a secure grip. [0021] - After the vacuum level has exceeded the gripping threshold, the isolation valve is closed by the cell controller. [0022] - While the isolation valve is in the closed state, the vacuum downstream of the valve is maintained by the sealed gripping face. [0023] - Before the workpiece reaches the set-down position, the workpiece is blown off by the blow-off valve while the workpiece is above the receiving surface. [0024] - The workpiece is held until the blow-off valve has opened the circuit. [0025] The cell controller reads the pressure sensor (each zone line) and commands the blow-off valve, the isolation valve; no sensor drives an actuator directly. 4. Parameters and operating assumptions [0026] 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 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); 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; material of the zone branches: plastic; zones of the zone branches: two (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); duration of the blow-off valve: a short pulse (sets how quickly the face clears and how much air each release costs); timing of the blow-off valve: before set-down (sets whether the pulse assists a drop release or clears the face after set-down). [0027] 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. [0028] The workpiece is released while it is still above the receiving surface and falls the remaining distance onto it. This sequence is for a workpiece and a receiving surface that tolerate that drop, for example a part released into a container or onto a conveyor; the drop height is set by the application and is not fixed here. [0029] The blow-off is a short pulse: the valve opens for a fraction of a second, long enough to break the seal and clear the face, and closes again. [0030] 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. [0031] 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. [0032] 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 [0033] 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-10259123-B2, US-11427405-B1, US-11858125-B2, US-8132312-B2, WO-2026020244-A1; their text is not reproduced, and the description above is generated from the structure of the combination. ------------------------------------------------------------------------ OpenTechnical publication OT-2026-000047751 Published 2026-09-17T08:33:24.028554Z https://opentechnical.org/p/OT-2026-000047751