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Electro-Mechanical Traveling Block Clamping


Area of application

The flexible block clamp unit of the type EFS is designed for mechanical and hydraulic presses exerting a force of ca. 500 tons force upwards. This includes large multi die station transfer presses. It is particularly suitable for top die clamping and require dies with straight clamping edges.

Mode of operation

The traveling block clamp unit type EFS: operates by means of an electric motor operating through a gearbox and a spindle. The angle clamping jaw is rotated about its position, and thus exerts a force on the clamping edge of the die. The clamp unit is secured in the T-slot of the ram and can be moved as required in this slot with the aid of the positioning unit type EFV.

Movement sequence for applying the clamping force:

Distinguishing features

The infinitely variable adaptation to different die widths renders standardization of the die/adaptor plates in terms of their width superfluous. Due to the continuous control of all important functions, and monitoring with the machine control system, fully automatic operation is ensured. The cables which are needed for transmitting the electrical signals and the drive power of the clamp unit are combined in a flexible trailing chain which travels in the machine T-slot.

Electrical control of the following functions (switches):

Technical Data

Motor: DC motor (EFV, EFS)
Supply voltage: 460 V, 60 Hz; n = 3000 rpm; (EFS)
N=1500 rpm (EFV),
S3-duty factor 15%
Switches: 4 inductive proximity switches (EFS)
1 inductive proximity switches (EFV)
p-n-p normally open contact
Sliding rate: 91 mm/sec.
Clamping rate: depending on type (see reverse)
Max operating temp.: 70°C
Wired to: plug-in connections



  • Large variable adaptation to different die widths
  • Large clamping thickness tolerance
  • Mechanical self-locking
  • Electrical control of all important functions
  • Automatic positioning at die
  • Continuous control/monitoring of clamping force


The clamp unit has a nickel-plated housing. A high-ratio epicyclic gear ensures the drive power required.

To secure the clamp unit to the machine, please use four M12 bolts, strength class 8.8 according to DIN 912 (not included).

Dimensional diagrams

Type FSP
A B C D E G M2)
EFS 60 60 100 50 75 0.55 1.4 383 170 160 120 102 180 42 65 30 80 53
EFS 120 120 200 50 75 0.75 1.4 415 170 160 120 123 180 42 65 30 80 56
EFS 240 240 450 60 80 1.5 0.9 512 210 200 150 123 240 42 65 30 80 98