---
publication_id: "OT-2026-000088236"
title: "Foam pad vacuum gripper, three zone face, common isolation valve, pump fed, supply line pressure sensor, sustained blow-off before set-down, on a tool changer"
published_at: "2026-09-17T09:03:15.638297Z"
canonical_url: "https://opentechnical.org/p/OT-2026-000088236"
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"
  - "robotics-automation/end-effectors/tool-changers"
keywords:
  - "zoned vacuum tool"
  - "tool-change interface"
  - "foam pad"
  - "vacuum pump"
  - "isolation valve"
  - "zone branch"
  - "pressure sensor"
  - "blow-off valve"
  - "blow off release"
  - "common isolation"
---

# Foam pad vacuum gripper, three zone face, common isolation valve, pump fed, supply line pressure sensor, sustained blow-off before set-down, on a tool changer

## Abstract

A zoned vacuum gripping tool comprising one tool-change interface, one foam pad, one vacuum pump, one isolation valve, three zone branches, one pressure sensor and one blow-off valve. When the foam pad reaches the workpiece, the foam pad is evacuated by the vacuum pump. 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 vacuum pump. 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 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] **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 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 sustained blast. 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 vacuum pump is fixed to the tool side of the tool-change interface.

[0011] The isolation valve is placed in the line from the vacuum pump, so that closing the valve cuts the whole circuit from the supply.

[0012] The three 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.

[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 vacuum pump and the distribution and reads the pressure of the whole circuit.

[0015] 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.

[0016] The robot side of the tool-change interface is bolted to the robot flange.

[0017] The pump motor is supplied from the electrical supply of the cell.

[0018] The blow-off valve is fed from the compressed air supply of the cell.

[0019] The isolation valve and the blow-off 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 vacuum pump.

- 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.

- After the vacuum level has exceeded the gripping threshold, the isolation valve is closed by the cell controller.

- While the isolation valve is in the closed state, the vacuum downstream of the valve is maintained by the sealed gripping face.

- 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 workpiece is held until the blow-off valve has opened the circuit.

[0027] The cell controller reads the pressure sensor (the common supply line) and commands the blow-off valve, the isolation 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 pad: sponge (sets the compliance of the sealing face); porosity of the foam pad: 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; 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); duration of the blow-off valve: a sustained blast (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).

[0029] 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.

[0030] The blow-off is a sustained blast: the valve stays open for the whole release so that the face is cleared of dust and the workpiece is pushed positively away.

[0031] 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.

[0032] 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.

[0033] 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

[0034] 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-8132312-B2, WO-2026020244-A1; their text is not reproduced, and the description above is generated from the structure of the combination.