Foam pad vacuum gripper, three zone face, per zone isolation, pump fed, pressure sensor per zone, sustained blow-off before set-down

Abstract

A zoned vacuum gripping tool comprising one mounting flange, one foam pad, one vacuum pump, three isolation valves, three zone branches, three pressure sensors, one contact detector 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 mounting flange, 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, starting the cycle at the moment of contact, 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 open cell foam.

[0004]One vacuum pump. The pump draws the circuit down mechanically and adds its own mass to the moving assembly.

[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]Three pressure sensors. Each pressure sensor taps the line it is placed in and reports the vacuum level in that line. The count of three follows from the arrangement: one sensor per zone branch. The pressure is measured at each zone.

[0008]One contact detector. The contact detector reports the moment a workpiece is present at the gripping face; its sensing technology is not fixed by this arrangement. The contact detector is mounted on the frame.

[0009]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.

[0010]The foam pad is carried on the tool side of the mounting flange.

[0011]The vacuum pump is fixed to the tool side of the mounting flange.

[0012]The three 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.

[0013]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.

[0014]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.

[0015]One pressure sensor is tapped into each zone line downstream of that zone's isolation valve, so that each of the three sensors reads its own zone and no other.

[0016]The contact detector is mounted on the frame and reports the moment a workpiece is present against the gripping face.

[0017]The blow-off valve is connected to the circuit at the pump inlet line, so that compressed air can be driven back through the circuit to the face.

[0018]The robot side of the mounting flange is bolted to the robot flange.

[0019]The pump motor is supplied from the electrical supply of the cell.

[0020]The blow-off valve is fed from the compressed air supply of the cell.

[0021]The isolation valves and the blow-off valve are switched by the cell controller; the pressure sensors and the contact detector report to the cell controller.

3. Operating sequence and conditions

[0030]The cell controller reads the pressure sensor (each zone line) and the contact detector (on the frame) and commands the blow-off valve, the isolation valves; no sensor drives an actuator directly.

4. Parameters and operating assumptions

[0031]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); drive medium of the vacuum pump: electric (sets the supply the pump motor needs from the cell); 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 sensors: at each zone (sets where in the circuit the reading is taken and what it describes); placement of the contact detector: on the frame (sets where the presence of the workpiece is detected); 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).

[0032]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.

[0033]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.

[0034]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.

[0035]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.

[0036]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.

[0037]A zone whose isolation valve is closed is cut from the common line and does not vent or blow off until its valve opens.

[0038]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

[0039]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, US-2022339798-A1, US-8132312-B2, WO-2026020244-A1; their text is not reproduced, and the description above is generated from the structure of the combination.