--- publication_id: "OT-2026-000008959" title: "Foam pad vacuum gripper, three zone face, per zone isolation, two stage ejector, supply line pressure sensor, vented after set-down" published_at: "2026-09-17T08:10:55.823363Z" canonical_url: "https://opentechnical.org/p/OT-2026-000008959" categories: - "robotics-automation/end-effectors/vacuum-grippers" - "sensors-controls-machine-vision/force-and-pressure-sensing/vacuum-sensors" - "industrial-motion-power-transmission/fluid-power/valves-and-manifolds" - "industrial-motion-power-transmission/fluid-power/vacuum-generation" keywords: - "zoned vacuum tool" - "mounting flange" - "foam pad" - "ejector" - "isolation valve" - "zone branch" - "pressure sensor" - "vent valve" - "compressed air supply" - "pressure sensing" --- # Foam pad vacuum gripper, three zone face, per zone isolation, two stage ejector, supply line pressure sensor, vented after set-down ## Abstract A zoned vacuum gripping tool comprising one mounting flange, one foam pad, one ejector, three isolation valves, three zone branches, one pressure sensor and one vent valve. When the foam pad reaches the workpiece, the foam pad is evacuated by the ejector. 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: one foam pad carried on a mounting flange, fed by an ejector. 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, controlling the moment of release and holding a workpiece that a rigid lip cannot seal against. 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 mounting flange.** The mounting flange carries the whole assembly and presents the bolt pattern that meets the robot. [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 ejector.** The ejector draws the circuit down by passing compressed air through a nozzle; it has no moving part at the tool and consumes air for as long as it runs. The ejector has two stages. [0005] **Three isolation valves.** Each isolation valve sits in the line it controls; closing it cuts that line without disturbing the rest of the circuit. The count of three follows from the arrangement: one valve per zone branch. Isolation is per zone. [0006] **Three zone branches.** Each zone branch carries the vacuum of one zone of the face and no other. The count of three follows from the arrangement: one branch per zone. The distribution is divided into three zones, each fed by its own branch. [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 pad is carried on the tool side of the mounting flange. [0010] The ejector is fixed to the tool side of the mounting flange. [0011] The three zone branches are taken from a branch junction on the ejector outlet, so that each branch carries the vacuum of its own zone only. [0012] One isolation valve is placed in each zone branch, so that closing that valve cuts its zone from the circuit and leaves the other zones under vacuum. [0013] 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. [0014] The pressure sensor is tapped into the line between the ejector and the distribution and reads the pressure of the whole circuit. [0015] The vent valve is connected to the circuit at the ejector outlet and opens that circuit to atmosphere when it is actuated. [0016] The robot side of the mounting flange is bolted to the robot flange. [0017] The ejector is fed from the compressed air supply of the cell. [0018] The isolation valves and the vent valve are switched by the cell controller; the pressure sensor reports to the cell controller. ## 3. Operating sequence and conditions - When the foam pad reaches the workpiece, the foam pad is evacuated by the ejector. - When the vacuum level exceeds the gripping threshold, a secure grip is signalled by the pressure sensor. - The workpiece may not be lifted unless the pressure sensor signals a secure grip. - When a zone is not covered by the workpiece, the isolation valve of that zone is closed by the cell controller. - While the isolation valve of that zone is in the open state, the vacuum of a covered zone is maintained by the ejector. - After the workpiece has reached the set-down position, the vacuum circuit is vented by the vent valve. - The workpiece is held until the vent valve has opened the circuit. [0026] The cell controller reads the pressure sensor (the common supply line) and commands the isolation valves, the vent valve; no sensor drives an actuator directly. ## 4. Parameters and operating assumptions [0027] Parameter values of this embodiment: 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); stages of the ejector: two (sets the flow drawn at low vacuum and the compressed air consumed while a sealed face is held); control of the isolation valves: per zone (sets which part of the circuit the valve cuts: one branch line on its own or the whole circuit); material of the isolation valves: steel; material of the zone branches: plastic; zones of the zone branches: three (sets how much of the face can be treated separately); 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). [0028] Which zones the workpiece covers is known to the controller from the workpiece programme; the arrangement provides the valve per zone and the controller decides which valves to close. [0029] 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. [0030] A zone whose isolation valve is closed is cut from the common line and does not vent or blow off until its valve opens. [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-10549431-B2, US-11427405-B1, 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 [0033] This publication supersedes OT-2026-000004643, 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: sensor placement moved from an absent manifold to the supply line; foam_pad material 'foam' is not offered by the library; the source-stated value 'sponge' is used.