Toggle Clamps

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Introduction To Clamps

What is a Toggle Clamp?

Toggle clamp is a simple Mechanism which holds instantly. The Toggle Clamps Consist of a handle to operate, a Clamping Arm to Reach the work piece, linkages for multiplying the applied force, and a base for mounting at the workplace on it’s base. The handle is operated which thereby moves the clamping arm to hold the work piece. A required clamping force is achieved and exerted on the work piece. Under this action the Toggle Clamp Holds the work piece firmly and positively.

Toggle Action Force Factors

Holding Capacity:

The holding capacity mentioned for each clamp refers to the maximum force, which the clamp can withstand after being over-centered without damage to the clamp and without the toggle unlocking due to distortion of the clamp.

The over-center dimension is carefully chosen in relation to the elasticity of the clamp to maximize clamping force while ensuring that the clamp locks closed even under vibration or intermittent loading.

For Hold Down Clamps, holding capacity is measured with the spindle at the farthest end of the clamping arm and will increase as the spindle goes closer to the clamping arm.

Clamping Force:

Clamping Force, the amount of force actually applied to the work piece by closing and locking the clamp, is generally less than the stated holding capacity. Actual clamping force depends on many factors including; spindle position, proper spindle height adjustment, spindle cushioning, work piece material and the clamps mechanical advantage. In most cases, roughly 1/3rd of the stated holding capacity can be applied by hand with medium effort.

Toggle Principle

Toggle action clamps operate through a linkage system of levers and pivots. The fixed length levers, connected by pivot pins supply the action and clamping force. Toggle action has an over centre lock point which is a fixed stop and linkage. Once in the over centre position, the clamp cannot move or unlock unless the linkage is moved. All types of toggle clamps have same action, just oriented differently.

The Toggle Mechanism in a clamp has three functions.

  • To multiply applied load at the handle into a high clamping force to hold the work piece.
  • To create an over - centre lock to prevent the clamp from opening & releasing the work piece until opened by the operator.
  • To rapidly open & close the clamp giving a maximum clearance in which to load & unload the work piece.

Types of Toggle Actions

This catalogue contains about 300 different standard toggle clamps & clamping systems. Steel-Smith has developed its range of clamps & clamping equipments for infinite applications, considering the different shapes, sizes, holding capacity, operator's position & strength, frequency of operation etc. Most of the Toggle Clamps belong to one of the following five main actions groups, which are:

Vertical Hold Down Action : (VTC- Series)

As the name implies clamps of this type hold the work piece with a downward clamping action. These clamps are manufactured with a holding capacity up to 3000 kgs. The clamping exhibits a minimum of 90o opening angle giving full clearance for loading & unloading of workpiece. Clamping arm can be solid bar, U shaped or fixed hole to suit individual requirements.

Horizontal Hold Down Action : (H- Series)

The holding action in these types of Toggle Clamps is same as VTC-Series clamp. The outstanding characteristic is the low height design. Unlike the handle & the clamping bar of the VTC-Series, these of the H-Series clamps move in opposite direction. The holding capacities range upto 1,000 kgs. The clamping arm can be solid bar, U shaped or fixed hole type.

Straight Line Action : (HTC- Series)

The straight line action toggle clamps design uses a straight-line or push/pull, Toggle clamping action. The push/pull handle is easy to operate & moves the plungers of the clamp in and out along its axis. Most of these clamps can be locked in two positions, allowing you to use them as either push or pull clamps. These clamps are manufactured in a variety of models to accommodate a wide range of load ratings.(45 kgs - 4,500 kgs)

Pull Action Clamps : (PAH-Series)

Steel-Smith's Pull Action Clamps are designed for sealing chambers, doors, mould closures or other such applications requiring closure mechanisms. The handle can be moved to place the clamping U - Bolt Bar hook around the opposing latch & pull down to reach the lock position. The threaded "hook" or "U-bolt” type bar offer an adjustment feature. The clamps can withstand pressures from 150 kgs. to 3000 kgs.

Squeeze Action Clamps : (TP- Series)

Squeeze Action Toggle Clamps hold parts with a pinching or squeezing action between two clamping jaws. The jaws are locking automatically when closing as one or both handle are Squeeze against the central position. The Squeezing action of the clamps makes them well suited for applications where they can replace ‘C’ clamps. The arms are drop-forged in steel & hence can withstand heat without deformation.

Testing facilities

Testing Facilities at Steel-Smith

At Steel-Smith all the clamps are tested for Holding Capacities, Clamping Force and Life cycle at state-of-the art testing facilities. If a particular application demands a certain Holding Capacity we design and re-inforce the clamp accordingly. All the clamps displayed in this catalogue are rated as per these tests and results.


  • H-45105-UB on Co2Welding fixture

  • H-4835-UB/FM in gauge checking fixture

  • H - 1330 - UB in a unique paper pad

  • HTC-4560-PS Clamps used for locating

  • VTC - 4595 - sb/bs on a checking gauge

  • HV Series Clamp in a BIW fixture

  • HV Series in fixture used with standard shimps

  • HV Series with modified Arm

  • AOT-98125-SB used in a SPM

  • Numerrous HV Series used in a Spot welding fixture

  • AOT-2530-HTC used to hold cylindrical w/p in tapping process

  • AOT-3586-SB used in a checking fixture

  • SSC-2550 used in a SPM

  • DCTC Series clamps on a Welding Fixture

  • H - Series Clamps used for Ladder Assembly

  • HTC - 5065 used in a pipe bending machine

  • PAH- 1210 in a Vibro-finishing machine

  • AOT Toggle Clamp used in Pipe Bending Machine

  • HV-BII-1000 in an Automotive welding fixture

  • AOT-HV-1200-H-TU-TU used in Truck Load Body Weling Fixture

  • H-237-U used in Screen Streching and Printing

  • HTC 350 FM used in a holding fixture

  • HTC-2530-PS used in Circuit Testing Fixture

  • HTC-3025 used in VMC machining

  • HV Series Clamps used in gauging fixtures

  • Latch Clamp used in Industrial Refrigerator

  • PAH-46-4000-TRIG used in Hood Locking

  • PAH-341-TRIG used in Die Closing

  • PAH-2445 used in Sieving & Filtering Machine

  • Pull Action Clamp & Latch Clamp used in Powder Coating Equipments

  • Pull Action Clamp used in Industrial Oven

  • Pull Action Clamp used in Machine Door

  • Pull Action Clamp used in Oven

  • Pull Action Clamp used in Truck Load Body

  • Pull Action Clamp used on Hatch Door of a Windmill

  • VTC 2535 UB used to clamp Glass door

  • PAH-30588 Latch used to clamp drum lid

  • VTC-4595-UB used in Pipe Welding

  • Multiple Hold Down Action Clamps used in Drilling Jig

  • HV-700-H used with special adpaters to hold a sheet metal component

  • VTC-2535-UB-T-SS Clamps used in a Pharma machine

  • SSC-Series Clamps in a Load body welding fixture

  • HV-700-H Clamps used in a BIW Fixture