Abstract
A foam-pad vacuum gripping tool comprising one mounting flange, one foam pad, one ejector, one pressure sensor and one blow-off 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 workpiece is blown off by the blow-off 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 foam-pad vacuum gripping tool: one foam pad carried on a mounting flange, fed by an ejector. It is arranged for 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 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]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.
[0006]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 after set-down.
[0007]The foam pad is carried on the tool side of the mounting flange.
[0008]The ejector is fixed to the tool side of the mounting flange.
[0009]The foam pad is connected to the ejector outlet by a single vacuum line, so that the face is evacuated through that line.
[0010]The pressure sensor is tapped into the line between the ejector and the foam pad and reads the pressure of the whole circuit.
[0011]The blow-off valve is connected to the circuit at the ejector outlet, so that compressed air can be driven back through the circuit to the face.
[0012]The robot side of the mounting flange is bolted to the robot flange.
[0013]The ejector is fed from the compressed air supply of the cell.
[0014]The blow-off valve is fed from the compressed air supply of the cell.
[0015]The blow-off valve is switched by the cell controller; the pressure sensor reports to the cell controller.
3. Operating sequence and conditions
[0016]
- When the foam pad reaches the workpiece, the foam pad is evacuated by the ejector.
[0017]
- When the vacuum level exceeds the gripping threshold, a secure grip is signalled by the pressure sensor.
[0018]
- The workpiece may not be lifted unless the pressure sensor signals a secure grip.
[0019]
- After the workpiece has reached the set-down position, the workpiece is blown off by the blow-off valve.
[0020]
- The workpiece is held until the blow-off valve has opened the circuit.
[0021]The cell controller reads the pressure sensor (the common supply line) and commands the blow-off valve; no sensor drives an actuator directly.
4. Parameters and operating assumptions
[0022]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); stages of the ejector: two (sets the flow drawn at low vacuum and the compressed air consumed while a sealed face is held); 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: after set-down (sets whether the pulse assists a drop release or clears the face after set-down).
[0023]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.
[0024]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.
[0025]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
[0026]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-10549431-B2, US-11427405-B1, US-8132312-B2, WO-2008134339-A4; their text is not reproduced, and the description above is generated from the structure of the combination.