Electric Grippers
Presenting… electric grippers. Tough and robust, with a huge grip force and moment capacities that allow large parts to be moved fast.
Traditionally, robot grippers are all pneumatic, even though the robot is electric and most of the tooling around the robot is electric. Electric grippers are seldom used anywhere because:
- they’re not available with large grip capacities for heavy loads
- the bodies of electric grippers are too small to lift heavy or large parts
- if power is lost, an electric gripper may lose a firm grip on the part
The Electric Advantage
Our line of electric grippers are all based on a unique, patent-pending feature: the grip is spring-loaded. The resulting advantages:
- The jaws close fast, with no slowdown before contact
- The grip force can be specified by varying the amount of spring compression
- The motor continues to spin after contact has been made, compressing the spring
- The force exerted by the gripper climbs higher and higher as the screw tightens
- The motor is shut off safely only when a threshold of force is met, without overloading the motor or the gear reduction
- A strong grip can be made no matter what size load appears between the jaws; the size of load could be changed unexpectedly and the gripper will still grip with just as much force
- The jaws maintain an iron grip, even if power is lost
- No power is required after the grip has been made; the grip will remain solid for hours or days after contact has been made
- There is no reduction in grip force (just like a pneumatic gripper), even if the load is accelerated or flipped upside down or if the load collides with an obstruction
Single-Acting vs Double-Acting
Single-Acting
The gripper shown is single-acting and has one jaw that moves while the other remains stationary. The robot brings the fixed jaw up against the load and then activates the moving jaw to close against the load. Note the industrial-grade linear bearings for precision and rigidity.
Double-Acting
In the double-acting gripper, on the other hand, both jaws (shown in transparent) move together in a synchronized way. The robot must position the wrist over the load with each jaw an equal distance away from the part before closing.
Controls
- The gripper is closed by a servomotor, which is controlled by a drive
- The drive, pictured here, is typically mounted remotely in the cabinet that houses the PLC, power supply, etc
- If there is no cabinet, the gripper can be supplied with a drive pre-mounted in an electrical box that can be attached to the gripper or elsewhere on the end effector
Sensing
- Grip Detect sensing is done by taking an output from the servo drive
- When the current draw rises during a grip, an output is generated by the drive
- Part Present sensing is done by adding a proximity switch or a limit switch
Jaws and Accessories
- Ordinarily, jaws for the gripper that close around the load are supplied by the customer, but if needed, we can provide them
- We would need detailed CAD of the part being lifted, along with information for the robot in use
- We can also provide the mount for the gripper to attach to your robot
Complete End Effectors ▶
We can provide the entire end effector, complete with gripper, jaws, sensors, and robot mount.
Single-Acting Gripper Options
G56ES Standard Gripper Specifications
Maximum grip force: 5000 lb or 2000N
Grip speed: 1 in/sec or 25mm/sec
Maximum grip moment, measured from the center of the screw to the point of contact with the load, multiplied by the grip force: 5,000 in-lb or 550 Nm
Jaw travel, maximum: 6 in or 150mm
Weight: 26 lb or 12kg
Voltage: 120V
Current Draw: 1A
Power Consumption: 100W
Naming convention of G56ES: “Gripper, 5,000 in-lb, 6” stroke, Electric, Single-Acting”
Double-Acting Gripper Options
G44ED Standard Gripper Specifications
Maximum grip force: 250 lb or 1,100N
Grip speed: 1 in/sec or 25mm/sec
Maximum grip moment, measured from the center of the screw to the point of contact with the load, multiplied by the grip force: 4,000 in-lb or 450 Nm
Jaw travel, maximum: 4 in or 100mm
Weight: 31 lb or 14kg
Voltage: 120V
Current Draw: 1A
Power Consumption: 100W
Naming convention of G44ED: “Gripper, 4,000 in-lb, 4” stroke, Electric, Double-Acting”
G56ED Standard Gripper Specifications
Maximum grip force: 500 lb or 2000N
Grip speed: 1 in/sec or 25mm/sec
Maximum grip moment, measured from the center of the screw to the point of contact with the load, multiplied by the grip force: 5,000 in-lb or 550 Nm
Jaw travel, maximum: 6 in or 150mm
Weight: 34 lb or 15.5kg
Voltage: 230V 1-ph
Current Draw: 1A
Power Consumption: 100W
Naming convention of G56ED: “Gripper, 5,000 in-lb, 6” stroke, Electric Double-Acting”
