Alternatives to Hydraulic Cribbing
Author: Michele Baker Ph.D
Table of Contents
Hydraulic systems are incredibly effective at lifting or moving heavy loads. They can multiply the force from a small engine to generate enough power to lift thousands of tons. Despite their power, these systems cannot suspend loads perfectly for an extended period. No hydraulic system is completely leakproof, resulting in cylinder drift. They can also fail unexpectedly.
Hydraulic cribbing is the traditional method of providing extra support to hydraulic systems. However, it has drawbacks, including inefficiency and a lack of precision. Several alternatives to cribbing effectively address these challenges, offering viable solutions.
What Is Cribbing, and How Does It Work?
Cribbing involves creating a sturdy support system to support a load, typically using uniform blocks, such as wood or plastic, for support. Traditionally, cribbing used wood, but today, many modern composites offer greater reliability. Here is how cribbing works in hydraulic systems:
- A hydraulic cylinder lifts a heavy object to the desired height.
- Individuals build a temporary crib underneath the object.
- Personnel carry out their work safely, without relying on hydraulic pressure.
Why Is Cribbing Important?
Cribbing is essential because hydraulic systems cannot hold a suspended load. Even if they could, these systems are not completely failsafe. Cribbing is vital for the following reasons.
Limiting the Risks of Pressure Loss
A hydraulic system must maintain steady pressure to hold a load. This pressure can gradually leak over time due to worn-out internal seals and valves. Pressure loss can also occur suddenly due to a burst hose, a broken fitting, a stuck valve or another malfunction. Cribbing provides a secondary source of stability.
Creating a Mechanical Failsafe
By using cribbing, you can transfer the weight of a load from the hydraulic fluid to a mechanical structure. The stack of blocks creates a physical structure that will support the load even if pressure shifts or complete failure occurs.
Meeting Safety Requirements
Various workplace operations require a secondary source of mechanical support for hydraulic systems. For example, the American National Standards Institute (ANSI) requires that automotive lifts be mechanically secured before technicians work under the load.
What Are the Drawbacks of Cribbing?
While cribbing is a suitable general solution for supporting hydraulic loads, it has some limitations. Here are a few reasons it may not suit your needs.
- Safety risks: Cribbing may be stacked ineffectively by personnel, or the cribbing materials could degrade over time, leading to unexpected failure. High-stakes applications like crane cribbing need more effective solutions.
- Operational inefficiency: Cribbing requires a significant amount of time to set up and remove, which can lead to increased operational costs. This time investment also makes it impractical for applications that require fast locking.
- Lack of precision: You can only set up cribbing at a fixed height, which creates significant limitations for tasks that require more precise positioning, such as wind-tunnel testing or aligning molds in large hydraulic presses.
How to Avoid Cribbing in Hydraulics
While cribbing is a suitable general solution for hydraulics, it may not be the best solution for every application and has significant downsides. If you want to avoid cribbing, you have several alternatives.
Hydraulic Load-Holding Valves
These pilot-operated valves hold a load using hydraulic pressure. This system offers several advantages over cribbing, including greater efficiency and precision. However, it still provides no mechanical lock. The solution could still experience internal leakage, leading to drifting over time. These valves depend on hydraulic integrity, rather than a mechanical solution.
Mechanical Locking Systems
Mechanical locking systems utilize a mechanism, such as jaws or pins, to grip the hydraulic cylinder rods. These systems do not require setting up separate cribbing and are often easier to use and more precise. The effectiveness of the system depends on the design.
Some are complex to operate, with many moving parts that could wear out or fail. Others cannot lock in any position, creating similar limitations to traditional cribbing. When choosing a mechanical locking system, prioritize a design with minimal moving parts and infinite adjustability. These design elements enable you to avoid many of the drawbacks of traditional cribbing.
Bear-Loc® — A Failsafe Hydraulic Stop
Not all mechanical locking systems offer the same level of reliability and adjustability. The Bear-Loc® from York Precision Machining & Hydraulics LLC provides a failsafe, infinite-position locking device to improve stability and control in the most high-stakes environments. The mechanism consists of a sleeve that creates an interference fit with the cylinder rod. This design means the positive mechanical lock does not depend on hydraulic pressure. It also eliminates the need for a separate solution, such as cribbing.
It locks instantly to avoid shuddering or other movement that could impact your precision or lead to on-the-job injuries. The design does not depend on adding moving parts. The lack of moving parts means less can go wrong, and you have fewer maintenance requirements. Bear-Loc® is versatile, offering various configurations and mounting styles to meet your specific application. Its benefits include:
- Increased employee safety
- Prevention of property damage
- Protection of equipment
Upgrade Your Hydraulic System With York Precision Machining & Hydraulics
Traditional cribbing is valuable in various scenarios, but if you seek alternatives to cribbing in a hydraulic system, consider modern solutions, such as Bear-Loc®. This option is safer, more efficient, and more precise for securing heavy loads. Learn more about this solution and how we can tailor it to meet your specific needs from York Precision Machining & Hydraulics.