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Hydro-Mechanical Retracting Turn Clamp


Area of application

The hydro-mechanical retracting turn-clamp unit type DESHV is designed for medium-sized and large presses exerting a force of ca. 500 tons upwards. It is particularly suitable for bottom die clamping , and for inner die clamping in draw presses. It is also used for top die clamping.

The clamp unit is installed rigidly in the surface of the ram or bed. Alternatively, it may be fitted to the ram bracket.

The use of the clamp unit requires dies that have lock plates or that have clamping edges with a U-recess.

Mode of operation

A double-acting hydraulic cylinder hydraulically initiates the clamping process by extending the tie rod outward. The tie rod is driven out to a point above the clamping edge of the die, into the clamping position. In the subsequent 90ยท rotation of the tie rod, a pinion is rotated by means of a toothed rod until the tie rod reaches the clamping position. In this position, an edge control bore allows the hydraulic pressure to flow to the clamping cyl inder which actuates the toggle mechanism. This hydraulically actuated but mechanically locking system transmits its clamping force to the die.

The mechanical locking effect, produced in the clamping position, is automatic and can only be released hydraulically.

Movement sequence for securing the slide:

Distinguishing features

The clamp unit is fitted with the well -proven Optima toggle mechanism. In this system, the clamping force required is transmitted by mechanical components which are actuated, only during the clamping or release process, by low hydraulic pressure.

The clamping force is continuously and directly controlled by the Optima "Aktivator". For this to function there must not be any hydraulic pressure on the clamp unit. In this type of control, the clamp units are connected to the machine control system via electrical switches (precision limit switches) and, in the event of irregularities, bring the machine to a standstill.

In the idle position, the tie rod is completely withdrawn into the surface of the bed or ram, and thus protected from damage. Die changing is therefore possible without interference.

Due to the standard equipment with a pre-clamping block, die thickness tolerances up to ±0.5 mm are permitted.

Electrical control of the following functions (switches):



  • Mechanical self-locking
  • Highest degree of safety due to continuous clamping force monitoring by means of the "Aktivator"
  • Central control
  • Hydraulic pressure only necessary during the clamping or release process
  • High mechanical load capacity


The clamp unit has a forged and gunmetal-finish tie rod.

The individual components of the toggle mechanism are made from various special alloys.Two hydraulic circuits are controlled by way of four hydraulic connections.

The clamp unit is secured by four M12 bolts of strength class 10.9 (not included).

Technical data

Type DESHV 100 DESHV 200
Nominal clamping force kN 100 200
Set pressure bar 100 100
Max. load capacity kN 125 250
Max. operating pressure (min. set pressure + 20 bar) bar 140 140
Release stroke mm (ca.) 3.5 3.5
Die thickness tolerance mm ± 0.5 ±0.5
Oil volume required (each process) clamping cm3 160.5 247.5
Oil volume required (each process) release cm3 278 412
Delivery rate per unit* l/min. 1.0-1.5 1.5-2.0
Weight kg (ca.) 63 90
Hydraulic connections see drawing
Max. operating temperature °C 70 70
Pressure medium Hydraulic oil DIN 51524 - HLP
(ISO DIN 51519)
Viscosity 25 - 60 cST/40°C
Filter 20 - 25 µm

*If a pump with a higher delivery rate than necessary is used, the oil flow must be reduced by means of flow regulating valves or oneway restrictors.

Precision position switches

Switching function: single-pole change-over
snap-action contact
Supply voltage: 250 V AC
Switching capability: 2A/230 V AC
5A/24 V DC
Contacts: screw connection
Cable lead-in: armoured cable 9

For a water- and oil-tight installation, we
recommend cable screw joints, in conjunction
with a protective sleeve.

Hydraulic Circuit DiagramHydraulic Circuit Drawing
Dimensional diagrams
Type FSP



a1) b
c d e f g h i
DESHV 100 100 125 190-150 500 ±0.5 3.5 80 30 32 36 130 91 119
DESHV 200 200 250 100-150 620 ±0.5 3.5 98 45 32 42 155 100 162
Dimensional diagrams
m n o
p r s t u w x y z Weight
112 125 92 75 35.5 65 50 M10 40 100 40 20 162 63
with stroke 90
114 150 107 90 35.5 62.5 50 M12 50 122 46 32 166 60
with stroke 120