Parallel Jaw Gripper

A gripper whose two fingers stay parallel as they open and close — the simplest and most common design.

A parallel jaw gripper has two opposing fingers that stay parallel to each other as they close together or move apart, much like an open-end wrench. It's mechanically simple, cheap, and grips reliably, and its action is usually described with a single number — the opening width, or simply open/closed — which is why it's the dominant end effector in robot learning: the large majority of data in datasets like Open X-Embodiment and DROID comes from parallel jaw grippers, and models like OpenVLA and π0 output a one-dimensional gripper action too. Grasping research often uses the concept of an antipodal grasp (where the contact forces at two points oppose each other) to analyze whether such a gripper can hold an object securely. Its limitation is that it struggles with tasks needing coordination across multiple fingers or in-hand adjustment.

ExampleOn the ALOHA bimanual platform, each arm ends in a two-finger parallel jaw gripper.

Also called

Parallel Gripper, Two-Finger Gripper

Related

Gripper · End Effector · Antipodal Grasp · Grasping · ALOHA · Franka Hand

Sources

Robotiq 2F-85 & 2F-140 Adaptive Grippers
Franka Hand（Franka Robotics 官网，二指平行夹爪） (Chinese)
Zhao et al. 2023: Learning Fine-Grained Bimanual Manipulation with Low-Cost Hardware (arXiv 2304.13705)