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LiftingSafety "Load Release" Remote Hook-Clamp - Range 590kg to 70 tonne (+ Specials)

Model:  LARH-4193

Tr Series S Series Air Series
LS-Series S-Series PNU-Series
Lm Series Rl Series Ram Series
LSLM-Series LSR-Series HYDRA-Series
Sqt Series
Release Type ?
Release Lever Type ?
Standard Reverse/Inverted (RL)
Clamp Mouth Type
Standard Large Diameter (LM/DM)
Capacity (SWL) (kg)

Unit Price £ Quote Only  
Part N°: 4193-13988720   Add to Quote Request

Manual, Hydraulic, Pneumatic Stainless Steel, Corrosion resistant SubSea Auto Remote Release Offshore Clamp

Standard And Reverse Lever

*Shackles not included - Available upon request.

LiftingSafety's Automatic release Hook-Clamps provide a unique method to Automatically release a load from the rigging and can easily be adapted to suit customers requirements. Fully corrosion resistant designed specifically for subsea and offshore use with a proven pedigree and reliability.

The LiftingSafety Automatic Load Release Hook-Clamp is perfect for when you need
to quickly release a load, it comes in a large range of working capacities (safe working loads) and can be fabricated to suit your needs with bespoke capacities, large (oversized) eyes etc...

The Hook-Clamp can be used in a multitude of ways:

  • To prevent the need to work at height, enabling the load to be disconnected from distance with-out the need to climb onto the load.
  • As a direct alterative to hydraulic release shackles, suitable for deepwater subsea operations.
  • Fully certified for use in the UK, Europe and the United states of America (USA), CE Marked and supplied with an EC Declaration of conformity / Operation and user manual.
  • Used to precisely place a load in position then remotely (and therefore safely) release the load from the crane hook (rigging gear). Using this method the clamp releases the load when the weight has been transferred to the floor, (other surface for example lorry trailer building, ground etc....)
  • The Auto HookClamp can also used as a drop test clamp or load dropping clamp. This is where the clamp is used to release the load "under load", for example when dropping sea defences into the sea from a boat.
  • Off-shore applications as used by the oil, gas, maritime, coastal, fishing, lifeboat industries etc....
  • Sub-Sea use, made completely from aerospace-grade stainless steel the HookClamp has the ultimate in corrosion resistance.
  • Third part whiteness test and certification available at extra cost (3rd party approval DNV, BV, Lloyds etc...)
  • Conversion for subsea ROV operation (Work class Remote operated vehicle also referred to as WROV usually by manipulator arm though also can be converted to hotstab.
  • A multitude of general Industrial applications; indeed for any application where the rigging gear needs to be disconnected though is is an awkward, difficult to get to position. Automatic remote release of the rigging gear prevents unavoidable accidents. 
  • Ideal for use in the water utilities industry to automatically place pumps into sumps or wet wells. 
  • The manual release lever can be supplied pointing down (towards the opening jaw) for automatic release applications below ground; pulling up releases the load (known as a reverse lever). Alternatively the release lever / arm can  be supplied  pointing up (towards the rigging gear / anchorage eye) and this is used for automatic release applications where the operator is below the load. Both lever types can release the load when the operator is adjacent to the HookClamp.
  • Back-up secondary safety hitch pin - The. manual release of the loaded Hook-Clamp can only be activated by first removing the safety / hitch pin. This is done either manually (directly by hand) or by a pull cord attached to the spring loaded safety hitch pin; ie, remotely and safety from a distance. The safety hitch pin release cord can be activated from any direction. Once the safety hitch pin has been removed the clamp is “loaded” or “Live” and pulling the cord attached to the release lever WILL DROP / RELEASE the load.

As standard the umbilical hose, hose reeler and power pack (HPU or pneumatic) supplied by the customer though we can quote to supply if requested.

Either end of the Hook-Clamp can be attached to a sling / shackle / hook allowing multiple uses,
The load can then be released by use of a lanyard pulling the release lever or by using one of the remote-load release options available, see the 'Options' tab for more information. (manual, hydraulic, pneumatic, squib-fired thruster.)

Standard Release Safety Pin Close Up

General Specifications

Video Example - Reverse Lever - Spring Release Safety Pin

Video Example - Reverse Lever - Manual (Pull) Release Pin

  • Fabricated by precision-cut computer-generated parts
  • Load Release Lever can be inverted (Standard or reverse)
  • Effort required to release the load can be adjusted to suit your application (effort can be reduced or increased)
  • Made from aerospace-grade stainless steel (corrosion resistant)
  • No Springs, reliable and robust design
  • Multi-Directional operation, can be used in the horizontal or vertical plain. To place a load safely and precisely or as a dropping clamp.
  • Low Friction resistance
  • Saftey Hitch Pin Safety Locking, maual or remotely spring loaded for remote activation (secondary safety back-up)
  • Safe Release Under Load if required (Use as a dropping or drop test clamp)
  • Safe working loads / Capacities range from 590kg to 69,000kg though special bespoke HookClamps are avaliable on request, so far we have designed and made units upto 250 tonne though greater capacities can be made on request
  • Special features are available On Request

Remote Release Safety Pin Option - Reverse Lever

360 View Spring Safety Pin Reverse Lever

Models and Available Options

Tr Series S Series Air Series
Manual Release - LS-Series (standard) Manual Release S-Series (Steel Supporting Plate Only for Horizintal applications only) Pneumatic / Compressed Air Release (Manual Release back-up) PNU-Series
The standard Hook-Clamp model, the lever is lifted to release the front clamp and allow the load to be released, it can be locked by a pin and ranges from 560kg to 69,000kg The "S-Series" Hook-Clamp is affixed to a steel plate to allow more accuracy when attempting to release a load, applications such as towing and off-loading in the ocean are perfect for this Hook-Clamp The "PNU-Series" Hook-Clamp is fitted with a compressed air cylinder (Pneumatic ram) and allows for air pressure to release the load. The Air Cylinders operate at 60 to 100 PSI.
Lm Series Rl Series Ram Series
Manual Release LSLM-Series (Large Diameter Mouth / opening jaw) Manual Release RL-Series (Inverted Release lever for activation / operation below the load) Hydraulic Release (Manual Release back-up) HYDRA-Series
The "LSLM Series" Hook-Clamp provides a "Larger Mouth" and is essentially just a modified "TR" model with an enlarged front clamp allowing for a higher capacity shackle, sling, lanyard or other connection. The "LSR Series" Hook-Clamp is simply a reversed lever. This can provide a better angle of load release in some cases. For example this option would be needed when the operator needs to release the shackle / rigging gear when the load is positioned above the operator.  The "HYDRA Series" Hook-Clamp is fitted with a hydraulic cylinder mounted below the device, This set-up can be used to replace a hydraulic release shackle (or hydraulic shackle) Above the cylinder is a plunger which penetrates through a hole in the body below the toggle pin. When this hydraulic system is activated, the cylinder pushes through the plunger and the toggle pin forcing the Clamp to release the shackle (or other rigging gear). The Hydraulic shackle release Hook-Clamp range can be operated remotely by a single 1/4" hydraulic hose. Can be operated by manual hand pump, remote accumulator or power pack (HPU) Most commonly used for subsea / offshore applications for hydraulic release of shackles.
Sqt Series
Squib or Squib-Fired Thruster Release (Manual Release Back-up) IB/IBT-Series
The "IB/IBT Series" Hook-Clamps feature either a squib or squib-fired thruster and are generally operated electrically and remotely. The Squib/Thruster offers a safe, split second release activation and the standard release lever is still available for further use. Squib activation is less expensive than the Thruster but thrusters offer a greater reliability.
Amination Single Tr Rl Tag Sling Hook D

General Information

  • General Product Design Features - The load release device combes an old and proven four-point-toggle-linkage principle with computer-generated parts precision-cut by water jet from aerospace-grade stainless steel plate. These parts are welded together and movably connected by pivot pins to form the device. The Remote load release device can be used subsea or on dry land, for automatic releasing of a shackle to place a load safely with-out the need for the operator to manual disconnection from the slings. It can also be used as a drop test or dropping devise. (for example dropping coastal defences into the sea).
  • Product Material / Specifications - All Remote load release device parts are longitudinally cut from aerospace-grade 15-5 PH stainless steel plate. Precipitation hardening stainless steels are chromium-nickel alloys. Pins are turned from 15-5 stainless steel round stock. All material is aircraft quality, grade XM-12 and meets the following specifications: AMS 5659, BMS 7-240, AMS 5862, and ASTM A564.
  • Welding, Heat Treatment, and Lubrication - All welding is with 17-4 SS wire only. All welded parts and pins are thoroughly cleaned and heat treated to H-1025 which increases the rating of the welding by 20-30% and the parts by 15%. Heat treating also results in improved mechanical, fatigue and corrosion properties across the board. Final assembly of the product includes the light application of a lubricant to each pin such as AQUA Lube, to protect the pin surfaces from pitting during extended marine use and aid in smooth mechanical function of the device. For higher capacity units, an NLGI #2.5 grease with moly added and a temperature range from 0 to 425F is applied. 
  • Quality Control - The manufacturer assumes the responsibility of inspecting each production unit for function, specifications, and appearance. Units not meeting the above rigid requirements are rejected.


  • Improper use of the Remote load release device may cause injury.
  • Hitch-pin must be used to totally prevent inadvertent release.
  • Do not use the Remote load release device release line as a tag line or put any tension on it until time to release. An additional tag line secured to the upper shackle and kept taught at all times is highly recommended to maintain a slack release line and prevent load twisting.
  • Stay clear of all objects released under load.
  • Do not exceed load capacity of this device.
  • Choose the proper size Remote load release device so that it is not loaded with or releasing more than its rated load.
  • Do not side load the Remote load release device as it may cause loss of retainer rings and other parts or permanently damage the device.
  • While in its loaded position, do not obstruct the Remote load release device so as to prevent its body being aligned straight with the line of load. Misalignment may prevent the movable jaw from releasing the connected member even with the device in the released position.
TR7RL Shackles Open


  • Inspection of the Remote load release device is advised after each use.
  • After use in or near sea water, a fresh water rinse of the Remote load release device is advised before it is stored.
  • Pivot pins may require periodic re-lubrication.

Load Definitions

  • Static Load: Forces solely due to the weight or gravity of objects being handled.
  • Dynamic Load: A load created by motion of the object that increases or decreases the static load.
  • Hydrodynamic Load: A load resulting from motion through the water including lift and drag.
  • Inertial Load: A load resulting from accelerated releasing caused by tension on the object that is greater than gravity.
  • Total Load: The sum of all above loads or forces acting on the object

Tr Sling D With Hook Hook Clamp Side TR Wire Sling
*Hooks/Shackles/Wire Rope/Slings not included, available upon request


Tr Dimensions
Part N° Recommended Shackle A B C D E F G SWL (kg) Breakload (kg) Weight (kg)
4193-T22955 Keyring -- -- 9.52 44.4 -- 4.76 31.75 NOT RATED 0.36
4193-T22956 1/4" 11.93 7.87 10.41 73.39 4.57 9.39 49.78 589 2,902 0.14
4193-T22957 7/16" 19.05 12.7 17.52 114.3 6.35 13.97 79.5 1,451 7,529 0.58
4193-T22958 5/8" 26.92 19.05 25.4 168.14 9.65 20.57 115.82 3,193 15,966 1.81
4193-T22959 3/4" 31.75 22.09 30.22 195.07 10.92 23.62 140.46 4,336 21,708 2.85
4193-T22960 1" 42.92 28.7 41.4 247.65 14.22 30.73 174.49 7,184 35,924 5.67
4193-T22961 1-3/8" 57.15 38.1 53.84 334.01 19.05 41.4 232.41 12,700 63,502 14.5
4193-T22962 1-1/2" 60.45 41.14 57.15 361.95 20.57 45.21 251.96 14,905 74,525 18.14
4193-T22963 1-3/4" 73.15 50.8 69.85 446.02 25.4 54.86 310.13 22,770 113,851 31.2
4193-T22964 2" 82.55 57.15 79.5 501.14 28.44 62.48 349.25 28,748 143,743 48.98
4193-T22965 2-1/2" 104.9 69.85 98.55 612.9 34.79 76.45 426.97 42,973 214,866 89.35
4193-T22966 3" 127 82.55 120.65 782.06 44.45 97.79 544.32 69,962 349,810 138.8
Hook Clamp Key

Usage Advice

As you can see from the image, the Hook-Clamp consists of several moving parts that allow the 'jaw' to open and release a load, generally you would use a release line to attach to the lever, pull this line and the load will release.

Alternative Methods of Release

These are the alternative methods for releasing the shackle:

  • Manually, pulling a long release line. No modification of the device is required. This method is used with lower capacity models, offers the lowest cost, and has many satisfied users.
  • Hydraulically, using a winch and cable, such as used with a deck-mounted crane, to pay out the load against a secured release line. No modification of the device is required for this method.
  • Hydraulically, paying out the load against a fixed-length, bulkhead-mounted release cable. Using a clevis instead of a shackle, a bulkhead-mounted hydraulic ram is attached to the rear end of the horizontally positioned devise to pull it back after the unit is locked. The release cable is then secured to the bulkhead and when release is desired, the hydraulic ram is actuated, allowing the Remote load release device to move toward the load and eventually against the secured release cable and the load releases the unit. This method allows the instalment of a pressure gauge into the hydraulic system to determine the actual tensile load being released. No modification of the device is required
  • Explosive electric squib thrusters inserted into a special chamber below the toggle pin are used successfully to activate the device.
  • Hydraulic pressure to drive a hydraulic cylinder to actuate the release lever of the Remote load release device is being used with the device ram models. These units can be activated by hydraulic hand pump, air-hydraulic foot pump, or electric pump. 
  • Air Cylinders provide another method of release and are fitted for activation using shop air at 60 to 100 PSI.

Device Locking

  • Having secured the recommended shackle to the rear end of the Hook-Clamp (anchorage / top suspension eye), open the jaw by removing the hitch pin and lifting up the release lever and opening it to the released position. Insert the pin of the shackle to be released into the jaw opening.
  • Secure the shackle by closing the release lever to the locked position and firmly lock the toggle pin over centre with a vice-grip-like snap.
  • The shackle is now held firmly locked even with no load on the device. The safety pin (Hitch pin) can be reinserted to prevent inadvertent release.
  • The Hook-Clamp is now ready to be loaded. Once the safety / hitch pin is removed, the Hook-Clamp is armed and ready to be released. Either to “set down” a load or to drop a load in a controlled manor (as a drop test / dropping clamp)

Device Releasing

Manual release of the loaded Hook-Clamp is activated by first removing the safety / hitch pin. This is done either manually (directly by hand) or by a pull cord attached to the spring loaded safety hitch pin; ie, remotely and safety from a distance. The safety hitch pin release cord can be activated from any direction.

Once the safety hitch pin has been removed the clamp is  “loaded” or “Live” and pulling the cord attached to the release lever WILL DROP / RELEASE the load. Pulling firmly on a release line connected to the end of the release lever also means that the operator can safety release the load away from the “danger area”. The release line can be activated “Directly” in any direction within the 90 degrees perpendicular and parallel to the line of load. The “Standard” release lever can also be operated from above the load as shown in the diagram below with the use of a suitable pulley; effectively giving 180 degree operation.

The Hook-Clamp can release the load with or without load on the unit. (providing the safety hitch pin is removed).

The use of the hitch pin is not required to secure the device in the locked position. It is an added, secondary safety measure preventing inadvertent release. A safety hitch pin is provided with each unit. The standard safety hitch pin is not spring loaded for remote operation (from distance by a pull cord).

Capacities and Release Capacities.


Detailed below are the figures of the estimated effort required to release a load at full capacity. This effort can be adjusted by following the instructions below.

Safe Working Load Estimated Effort To Pull Lanyard To Release Capacity Load (Can be adjusted, see below)
590kg 3.62kg
1,507kg 8.61kg
3,194kg 18.14kg
4,342kg 39.91kg
7,186kg 65.77kg
12,776kg 117kg
14,902kg 136.53kg
22,770kg 208kg
28,747kg 263kg
42,975kg 393kg
69,960kg 640kg

Remote Load Release Device Hitch-Pin

The hitch pin can be supplied "Spring Loaded" remote triggered release. This means that the hitch pin can be remotely removed from the body of the Hook-Clamp by use a pull-cord attached to a spring loaded hitch pin and therefore ensuring an additional level of safety even when the operator cannot physically reach the hitch pin to physically release it!

Adjusting The Effort Required to Operate the Manual release lever (Remote load release device Over-Centre Pressure Adjustment)

Standard Release Safety Pin Close Up
Standard Release Safety Pin Design
Spring Release Safety Pin R Clip Close Up
Spring Release Safety Pin R Clip Design

Ample material has been left at the tip of the movable jaw (see arrow) where the jaw and body come in contact. This aids in holding the device securely over-centre in the locked position even when no load is applied to the device. It also helps prevent inadvertent release of the device.

Should the user require that the effort to lock the release lever of the device over-centre be reduced, the procedure is to locate the area where the surface of the jaw comes in contact with the body and lightly file or grind off material in that area.

It is important to test the effort frequently after some material has been removed so as to prevent the removal of too much material.

Should the user require that the effort to lock the release lever of the device over-centre be increased, the procedure is to increase the thickness of the material between the two surfaces by applying a center punch mark in the area of the jaw where the surfaces meet. Should there still be insufficient material to ensure the positive locking integrity of the device, the contact area of the jaw will need to be spot-welded. This welded material will then need to be ground to the appropriate thickness.

Release Operation

Standard Release Lever Reverse Release Lever Standard Lever Release with Pulley
(the same can be done with reverse lever if necessary)
Standard Lever Release Diagram Reverse Lever Release Diagram Standard Lever Release Diagram With Pulley
HookClamp UserManual.pdf

Operation and User Manual

Complete operation and user instructions for the Hook-Clamp remote/automatic release hook
(approx. 1.2Mb)

Contact Us About This Product

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