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Hydraulic Cylinders & Actuators

Our qualified staff has over 40 years of experience in the design and manufacture of Hydraulic Cylinders for Industrial, Mobile, Aerospace and Defense applications.

  • Bore sizes from 1 1/2" thru 48"
  • Pressures of 2,000 PSIG thru 10,000 PSIG
  • Tie Rod, Threaded End Cap and Bolted End Cap Construction
  • Quality Control, SPC, 100% Testing
  • CAD/CAM Design and Manufacturing

Wellman Dynamics Machining and Assembly, Inc. manufactures high quality double or single acting and spring loaded Hydraulic Cylinders produced from steel, stainless steel, aluminum and materials. Call our Sales and Marketing Department to discuss your application and special requirements.

Industrial/Piston Accumulators

Our qualified staff has over 40 years of experience in the design and manufacture of Hydraulic Cylinders for Industrial, Mobile, Aerospace and Defense applications.

  • Safety vents in gas and liquid ends warn of internal pressurization
  • Aluminum piston with anodized finish resists pitting
  • T-Seal with dual back-up rings assure separation with minimum drag
  • Dual outboard wear strips prevent piston rub and provide larger balanced bearing areas. 
  • Oil or water service availability
  • -20°F to 275°F operating temperature range
  • Optional safety fuse
  • Custom designed to your specifications
  • Other material types available contact WDMA Sales for more information.

BEAR-LOC® - Locking Device

BEAR-LOC® is a simple, reliable locking device which can be used where infinite position locking, zero backlash and high system stiffness are required.

BEAR-LOC® has a unique patented design based on the principle of elastic expansion of metal under pressure. It is simpler, more efficient and more reliable than any other available locking system on the market.

BEAR-LOC® has been designed in a wide range of sizes, with rod diameters from 1 inch to 27 inches, sleeve lengths from 1 inch to seven feet and lock capacities to 4 million pounds.

Large-Size Capabilities!

Automatic Locking

BEAR-LOC® always locks automatically when sleeve pressure is relieved, whether its removed on command or lock pressure loss occurs. Locking action is positive. Movement is impossible when the BEAR-LOC is operated within its lock capacity.

Design Simplicity

BEAR-LOC's capability does not depend on adding moving parts, values or other components for its positive mechanical lock.

Infinite-Position Locking

The cylinder rod can be engaged by the locking section of the sleeve at any position in the stroke.


BEAR-LOC® offers a wide range of configurations and mounting styles to meet almost any space envelope requirements.

Configurations available are:

Lock Unit Only, Locking Actuators, Piston Locks, Mill Type and Tie Rod Construction.

BEAR-LOC® Operating Principle

The BEAR-LOC® Section is comprised of a cylinder rod and liners enclosed in a sleeve which forms an interference fit with the outside diameter of the rod. This fit provides a positive mechanical connection to lock the rod in any phase of the stroke. As soon as hydraulic pressure is applied the sleeve expands radially within the elastic limits, relieving the interference and creating enough clearance for the rod to be stroked with minimal resistance. Simply removing the hydraulic pressure via the unlock port allows the BEAR-LOC to re-engage automatically. Thus even with accidental lock pressure loss, the BEAR-LOC offers totally automated operation.

BEAR-LOC® units can be supplied in a wide variety of configurations. Contact the Sales/Engineering Department today for additional information or to discuss your special applications.



Utilizes Rotary, Linear and Jacking Bear-Loc's

Missile Launchers

Inherent locking system stiffness provides accuracy and stability as required in missile launchers.

Material Handling Equipments

Locks conveyors and chutes in position with power off.

Man Lifts

When system safety is critical use Bear-Loc.

Drilling Rigs

Long term heavy duty, heavy load offshore applications.

Coal Crushers

Suitable for the harsh conditions and high frequency vibration in corrosive atmosphere.


Platen adjustment requires in finite position mechanical locking under heavy load cycling.

Tug & Barge Connections

A unique Bear-Loc application with 4,000,000lb lock capacity.

What to know when ordering

BEAR-LOC units can be supplied in a wide variety of configurations for locking both liner and rotary motion.

  • Quantity required
  • Cylinder bore, rod size and mounting style
  • Unlock pressure (2000, 3000, 5000 psi)
  • Lock length
  • Required locking capacity
  • Length of stroke
  • Type of cushioning:
    • Non-cushioned
    • Cushioned rod end
    • Cushioned blind end
    • Cushioned both ends

Also specify: Position of port (if other than shown), unusual operating conditions (such as high or low temperature), type or fluid, etc.

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