How Strong is the Arch's "Guardian"?

When considering the support and stability of your leather shoes, you might encounter the term "shank" or "hook." This internal component, located between the heel and the ball of the foot, acts as the backbone of the shoe, providing crucial arch support and overall rigidity. You might search for terms like "leather shoe shank," "shoe shank stiffness test," "arch support test," "shoe stability," or the standard "BS 5131." This article explains the importance of shank stiffness in leather shoes and how it is measured using a leather shoe hook stiffness testing machine.
 

The Crucial Role of the Shoe Shank

The shank, often made of steel, wood, leatherboard, or composite materials, is a hidden but vital element in the construction of many leather shoes. Its primary functions include:

Arch Support: Preventing the arch of the foot from collapsing inward, which can lead to discomfort and foot problems.
 

Stability: Providing torsional rigidity, preventing the shoe from twisting excessively during movement.

Structural Integrity: Contributing to the overall shape and support of the shoe.

Proper Gait: Facilitating a more natural and efficient walking motion.

The stiffness of the shank directly influences the level of support and stability the shoe provides. A shank that is too flexible may not offer adequate arch support, while one with appropriate stiffness contributes to a more comfortable and stable wearing experience.
 

Introducing the G645 Leather Shoe Hook Stiffness Testing Machine

The G645 Leather Shoe Hook Stiffness Testing Machine is a specialized instrument designed to accurately measure the longitudinal bending stiffness of leather shoe shanks (hooks). By quantifying this stiffness, manufacturers can ensure that their shoes provide the intended level of support and stability, meeting both performance requirements and relevant industry standards.
 

The Principle of Measuring Bending Under Load

The machine operates by simulating the forces that act on the shank during walking. The heel portion of the shank is securely fixed in an adjustable rear fixture, typically set at a 30-degree angle to mimic the heel's inclination. A controlled load, applied at the front end of the shank (the part that sits under the arch), causes the shank to bend and deform. The machine then precisely measures the degree of this bending. By correlating the applied load with the resulting deflection, the bending stiffness of the shank can be calculated. A stiffer shank will exhibit less bending under the same load.
 

Decoding Relevant Standards

Several standards address the stiffness of shoe shanks, including:

BS-5131/4 (Footwear - Part 4: Tests for complete shoes). This British standard includes methods for assessing the stiffness of shoe components, including the shank.

QB/T1812 and QB/T1813 (Leather shoes). These Chinese industry standards for leather shoes may include requirements related to shank stiffness.

QB/T4329-2012 (Athletic footwear). This standard for athletic footwear may also specify shank stiffness requirements depending on the intended use of the shoe.
 

SATRA TM58 (Flexing resistance of insoles and stiffeners). While not solely focused on shanks, this SATRA test method addresses the flexing properties of similar stiffening components in footwear.

These standards often specify minimum stiffness values that shanks must meet to provide adequate support and stability.
 

Technical Aspects Demystified

Adjustable Angle of the Rear Fixture (30°): This fixed angle ensures consistent positioning of the heel part of the shank during testing.

Special Card Length (60±0.02mm): This standardized length provides a consistent point for load application on the front end of the shank.

Front Splint Thickness (12mm): The splint ensures stable and controlled transfer of the applied load to the shank.

Accuracy (0.01mm) and Measuring Range (0.01-10mm): The high accuracy and measuring range of the instrument allow for precise measurement of even small degrees of bending.

Applied Load (200g x 4pcs): The use of calibrated weights ensures a consistent and measurable force is applied to the shank.
 

The Importance of Proper Shank Stiffness

Appropriate shank stiffness contributes to:

Effective Arch Support: Preventing overpronation and reducing strain on the plantar fascia.

Enhanced Stability: Providing a more stable platform for walking and other activities.

Improved Comfort: Reducing foot fatigue and providing a more supportive feel.

Proper Gait Mechanics: Facilitating a more natural and efficient stride.

Benefits for Manufacturers and Consumers
 

For manufacturers, shank stiffness testing provides:

Material Selection: Allows for the evaluation of different shank materials and their stiffness properties.

Design Optimization: Helps in designing shanks with the appropriate stiffness for the intended use of the shoe.

Quality Control: Ensures that the shanks used in their shoes meet the required stiffness standards.

Performance Differentiation: Enables them to market shoes with specific levels of support and stability.
 

For consumers, this testing translates to:

Comfortable and Supportive Shoes: Footwear with properly stiff shanks can provide better arch support and reduce foot fatigue.
 

Improved Stability: Enhanced stability during walking and other activities.

Better Foot Health: Adequate arch support can help prevent various foot problems.
 

Conclusion: Understanding the Unseen Support System

The shank in a leather shoe is an often-overlooked but critically important component that provides essential arch support and stability. The G645 Leather Shoe Hook Stiffness Testing Machine allows manufacturers to precisely measure this stiffness, ensuring that their footwear is designed and constructed to provide the necessary support for comfortable and healthy wear. This unseen "guardian" of the arch plays a significant role in the overall performance and well-being of your feet.