Abstract
A zoned vacuum gripping tool comprising one mounting flange, one foam pad, one plant vacuum connection, three isolation valves, 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 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 mounting flange, 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 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 closed 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]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 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 mounting flange.
[0010]The three zone branches are taken from a branch junction on the plant vacuum connection, so that each branch carries the vacuum of its own zone only.
[0011]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.
[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]The pressure sensor is tapped into the line between the plant vacuum connection and the distribution and reads the pressure of the whole circuit.
[0014]The blow-off valve is connected to the circuit at the plant vacuum connection, so that compressed air can be driven back through the circuit to the face.
[0015]The robot side of the mounting flange is bolted to the robot flange.
[0016]The blow-off valve is fed from the compressed air supply of the cell.
[0017]The isolation valves and the blow-off valve are switched by the cell controller; the pressure sensor 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.
[0020]
- The workpiece may not be lifted unless the pressure sensor signals a secure grip.
[0021]
- When a zone is not covered by the workpiece, the isolation valve of that zone is closed by the cell controller.
[0022]
- While the isolation valve of that zone is in the open state, the vacuum of a covered zone is maintained by the plant vacuum connection.
[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 (the common supply line) and commands the blow-off valve, the isolation valves; no sensor drives an actuator directly.
4. Parameters and operating assumptions
[0026]Parameter values of this embodiment: 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); 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); 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]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.
[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 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.
[0031]A zone whose isolation valve is closed is cut from the common line and does not vent or blow off until its valve opens.
[0032]The tool carries no valve between the plant line and the face, so the plant vacuum is applied to the face whenever the plant line is live; release relies on the release element alone.
[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-10259123-B2, US-10549431-B2, US-11427405-B1, US-8132312-B2, WO-2026020244-A1; their text is not reproduced, and the description above is generated from the structure of the combination.