Abstract
An end effector for porous-face vacuum end-of-arm tooling is described. The tool comprises a mounting flange (10), a foam pad (12), a vacuum pump (14), a contact detector (16), a pressure sensor (18). The arrangement addresses starting the vacuum at the right moment in the approach, where evacuating before the face touches the workpiece wastes air and pulls dust into the circuit, and evacuating late leaves the tool pressing on a workpiece it has not yet gripped. The description covers what detects contact, what that detection starts, and the order of the two events. Every connection is stated with the medium it carries, and the operating sequence is given as conditions on named operations.
1. Technical Field
[0001]This disclosure relates to porous-face vacuum end-of-arm tooling. It concerns the arrangement of a gripping interface, the supply that feeds it, the distribution and control between them, and the sequence in which those parts act on a workpiece. FIG. 1 shows the arrangement as a block diagram with the reference numerals used throughout this description.
2. Technical Context
[0002]The arrangement addresses starting the vacuum at the right moment in the approach. The difficulty is that evacuating before the face touches the workpiece wastes air and pulls dust into the circuit, and evacuating late leaves the tool pressing on a workpiece it has not yet gripped. A tool that does not address it is still usable on a narrow range of workpieces, and the cost appears as cycle time, dropped parts or air consumption rather than as an outright failure. What follows covers what detects contact, what that detection starts, and the order of the two events.
3. System Overview
[0003]The tool comprises the mounting flange (10), the foam pad (12), the vacuum pump (14), the contact detector (16), the pressure sensor (18). FIG. 1 shows how these blocks are connected and which medium each connection carries. The blocks are not interchangeable by name: a connection is made only where one block offers a medium that another needs, and each connection below is stated together with the medium it carries.
[0004]FIG. 2 shows elevation of the gripping face on its mounting.
[0005]FIG. 3 shows signal path between the controlled elements and the cell controller.
[0006]
- The mounting flange is bolted to the robot flange (10).
[0007]
- The foam pad is connected to the vacuum pump by a vacuum line that opens into the distribution chamber behind the porous face (12).
[0008]
- The foam pad is mounted on the mounting flange (12).
[0009]
- The pump motor is supplied from the electrical supply of the cell (14).
[0010]
- The detector watches the foam pad and reports when a workpiece is present at that face (16).
[0011]
- The pressure sensor is tapped into the line at the vacuum pump and reads the pressure in that line (18).
4. Components
[0012]Mounting Flange (10). The mounting flange (10) is provided once in this arrangement. The flange carries the whole assembly and presents the bolt pattern that meets the robot.
[0013]Foam Pad (12). The foam pad (12) is provided once in this arrangement. The pad presents a porous face, so the holding force is spread over the contact area rather than concentrated at a lip. The pad is made of sponge. The pad is of open cell foam.
[0014]Vacuum Pump (14). The vacuum pump (14) is provided once in this arrangement. The pump draws the circuit down mechanically and adds its own mass to the moving assembly. The pump is driven by a electric motor.
[0015]Contact Detector (16). The contact detector (16) is provided once in this arrangement. The detector watches the face and reports the moment a workpiece is present against it. The detector is placed on the gripping face.
[0016]Pressure Sensor (18). The pressure sensor (18) is provided once in this arrangement. The sensor taps the line and reports the level it reads, which is what makes the state of the grip observable. The pressure is measured at each zone.
5. Operation
[0017]The operating sequence is given as conditions on named operations. Each condition names the event it depends on and the operation it governs, so the order of events is explicit rather than implied by the order of the sentences. FIG. 2 shows the gripping face referred to in these steps. The tool is presented to the workpiece square to the face, and the numbered operations below are what the arrangement does from that point.
[0018]
- When the foam pad seals the workpiece, the foam pad is evacuated by the vacuum pump.
[0019]
- After the contact detector has detected the workpiece, the vacuum supply is actuated.
[0020]
- When the vacuum level exceeds the gripping threshold, a secure grip is signalled by the pressure sensor.
[0021]
- The workpiece may not be lifted unless the pressure sensor signals a secure grip.
[0022]An operation whose condition is not met does not run. A condition that is stated with UNLESS holds except while its event is true, and one stated with UNTIL ends the operation at the moment its event becomes true. With the workpiece released, the tool returns to the pick position and the cycle repeats.
6. Example Embodiments
[0023]In one embodiment the gripping face carries 1 foam pads on a common mounting, fed as shown in FIG. 1, and the tool is presented to the workpiece square to the face. In a second embodiment the same face is arranged in two rows so that a long workpiece is supported at both ends, with the connections of FIG. 1 unchanged. In a third embodiment the face is built at half the pitch and the number of foam pads is doubled for the same envelope, which suits a workpiece that is lighter but less rigid.
7. Alternative Configurations
[0024]The gripping face may instead use a folded bellows cup, which takes up height differences at the cost of lateral stiffness. The gripping face may instead use a flat cup, which is stiffer laterally but needs the face and the workpiece to meet squarely. A gripping face of this kind may also be replaced by fingers closing on the workpiece, which removes the air circuit entirely and requires access to two opposed surfaces of the workpiece. The pump may be replaced by an ejector, which removes the moving part at the tool and spends compressed air while it runs, or by a connection to a plant vacuum line. An isolation valve may be added in the line to each zone, which allows one part of the face to be cut from the circuit while the rest holds its vacuum.
8. Parameter Variations
[0025]Each parameter below is stated with what it changes in the arrangement. The porosity of the foam pad is open cell in the arrangement described; varying it changes the flow drawn through the face and the vacuum level that can be held behind it. The placement of the contact detector is on the gripping face in the arrangement described; varying it changes whether contact is reported for the face as a whole or for one part of it. The placement of the pressure sensor is at each zone in the arrangement described; varying it changes whether the reading describes the whole circuit or one zone of it.
9. Additional Implementations
[0026]The whole assembly may be carried on a tool-change interface so that it can be exchanged between jobs without dismantling the tool. A separating element may be added so that a workpiece which follows the face upwards after release is pushed off positively. The face may be divided into zones, each fed by its own branch, so that a workpiece covering part of the face is handled without the uncovered part being held under vacuum. The arrangement may be duplicated on one mounting so that two workpieces are handled in one cycle, with the distribution fed from a common inlet and each face controlled on its own.
10. Provenance and method
[0027]This document is an original combination composed from a typed library of mechanism blocks. Each block was derived from the published patent literature and carries typed connection points, the parameters its source states, and its own construction and operating description. The combination described here is proposed rather than taken from any one source, and it is not asserted to have been constructed. The published documents behind the blocks used in this arrangement are EP-4385681-B1, US-10549431-B2, US-11427405-B1, US-2022339798-A1. Their text is not reproduced here; the description above is generated from the structure of the combination.
11. Figures
