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 ejector (14), a zone branch (16), a contact detector (18), and a blow-off valve (20). The arrangement addresses putting the workpiece down quickly without it sticking to the face, where a vented cup releases at the speed the circuit refills, and a light workpiece can stay stuck to a damp elastomer face long after the vacuum is gone. The description covers where the pulse is injected, when it is given relative to set-down, and how long it lasts. 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 putting the workpiece down quickly without it sticking to the face. The difficulty is that a vented cup releases at the speed the circuit refills, and a light workpiece can stay stuck to a damp elastomer face long after the vacuum is gone. 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 where the pulse is injected, when it is given relative to set-down, and how long it lasts.
3. System Overview
[0003]The tool comprises the mounting flange (10), the foam pad (12), the ejector (14), the zone branch (16), the contact detector (18), the blow-off valve (20). 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 ejector 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]
- Compressed air is fed to the ejector from the compressed air supply of the cell (14).
[0010]
- Each zone branch is taken from the ejector, so that the branch carries the vacuum of its own zone only (16).
[0011]
- The detector watches the foam pad and reports when a workpiece is present at that face (18).
[0012]
- The blow-off valve is fed from the compressed air supply of the cell (20).
[0013]
- The blow-off valve is connected to the circuit at the ejector, so that a pulse of compressed air can be driven back through it (20).
[0014]
- The blow-off valve is switched by the contact detector (20).
4. Components
[0015]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.
[0016]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.
[0017]Ejector (14). The ejector (14) is provided once in this arrangement. The ejector draws the circuit down by passing compressed air through a nozzle, so it needs no moving part at the tool. The ejector is built with 1 stages.
[0018]Zone Branch (16). The tool carries 1 zone branches. Each branch feeds one zone of the face, so the zones can be treated separately. The zone branch (16) is configured with material plastic. The face is divided into 3 zones.
[0019]Contact Detector (18). The contact detector (18) 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.
[0020]Blow-Off Valve (20). The blow-off valve (20) is provided once in this arrangement. The blow-off valve drives compressed air back through the circuit, which clears the face rather than waiting for it to refill. The pulse is a short pulse. The pulse is given after set-down.
5. Operation
[0021]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.
[0022]
- When the foam pad seals the workpiece, the foam pad is evacuated by the ejector.
[0023]
- After the contact detector has detected the workpiece, the vacuum supply is actuated.
[0024]
- After the workpiece has reached the set-down position, the workpiece is blown off by the blow-off valve.
[0025]
- The workpiece is held until the blow-off valve has opened the circuit.
[0026]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
[0027]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
[0028]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 ejector may be replaced by a pump at the tool, which stops the continuous air draw and adds mass to the moving assembly, or by a connection to a plant vacuum line, which removes the generator from the tool and couples the tool to the rest of the site. 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. The blow-off may be replaced by a plain vent, which releases at the rate the circuit refills and needs no compressed air at the moment of release.
8. Parameter Variations
[0029]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 stages of the ejector is 1 in the arrangement described; varying it changes the flow drawn at low vacuum and the air consumed to hold a sealed face. The zones of the zone branch is 3 in the arrangement described; varying it changes how much of the face can be isolated at once and how small a workpiece the tool can still hold. 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 duration of the blow-off valve is a short pulse in the arrangement described; varying it changes how quickly the face clears and how much air each release costs. The timing of the blow-off valve is after set-down in the arrangement described; varying it changes whether the pulse assists set-down or clears the face after it.
9. Additional Implementations
[0030]A pressure sensor may be tapped into the circuit so that the state of the grip is observable, and the motion that follows the grip may be made conditional on the level it reports. 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 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
[0031]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-2022339798-A1, US-8132312-B2, WO-2008134339-A4, WO-2026020244-A1. Their text is not reproduced here; the description above is generated from the structure of the combination.
11. Figures
