A bag gripper for an ABB IRB 460 palletising robot. The jaws were driven by two independent air cylinders and could drift apart. I coupled them mechanically with a rack and pinion and issued DIN-ISO drawings.
An existing gripper assembly: a frame, two jaws on guides, each pulled by its own air cylinder. Nothing synchronises the jaws, so a bag can be picked up skewed.
My part: a mechanism that makes both jaws move as mirror images, three JPGs explaining the solution and DIN-ISO drawings for three parts.
The mechanism had to fit into someone else's finished assembly without redesigning frame, jaws or cylinders.
Minimal changes. New parts fix to the existing frame and carriages through holes that are easy to add, using the same DIN 912 M6 fasteners already in the assembly.
Mirrored jaws. The right jaw is the same part rotated 180°. Rack and holder live inside the jaw component, so the second jaw gets them automatically.
100 mm stroke. Each jaw travels 100.1 mm inwards. Over the whole stroke the racks must clear the frame, cylinders and fingers.
Load. Worst case: one Ø25 cylinder at 6 bar pulls both jaws through the mesh, about 295 N per tooth.
One central idler pinion and two racks, one on each jaw, teeth facing each other.
m2 z30 pinion (d60, b20) on a vertical axle at the centre, 3202-2RS bearing
Ø15 shouldered axle, M10 through the frame with a DIN 986 nut; 80 × 60 × 26 aluminium bracket on 4 × M6
m2 20 × 20 racks, 232.48 mm long, with holders inside the jaw component
Stroke check at 0/25/50/75/100/105 mm: no collisions; with the pinion turned the wrong way, clashes appear
Calculation: about 21 MPa in the tooth, up to 590 N on the axle, about 25 MPa in the axle
Jaw finger 02.552: 5 mm S235JR plate, RAL 1003, flat pattern per DIN 6935, 5.03 kg. Weldment 03.001: shaft, bent bracket and lever, ISO 2553 welds, 3.44 kg. Pin 03.542: 1.4305, 0.07 kg.
DIN-ISO drawings: ISO 5457 frame with zones, ISO 7200 title block, first-angle projection, general surface finish, numbered notes in English.
02.552: views, section A-A, isometric and flat pattern with ordinate dimensions. 03.001: A2 weldment with parts list. 03.542: A4 pin with view X at 5:1.
The jaws are mechanically coupled: if one cylinder lags, the pinion pulls its jaw along and the bag is picked level.
Changes to existing parts come down to a few holes, and everything new uses the assembly's standard fasteners.
Send a sketch or a photo, and within 24 hours I'll tell you how long it takes and what I need from you.
Discuss your project Message on Telegram
