The Versatility of Variable Force Springs in the POP Industry

Let’s talk about another very popular flat steel spring design—variable force springs, also known as v-springs or variable tension springs. These springs are quite prevalent in the Point-of-Purchase, or POP, industry, especially in pusher trays and feed displays.

V-springs deliver variable force to precisely match increasing or decreasing force requirements. This pushes products forward toward the front of the display either horizontally, like in a pusher tray, or vertically, like in an upfeed design. These springs can be seen in the tobacco, cosmetic, electronic and medical industries thanks to their wide applicability. Displays containing variable force springs can be used for moving and supporting lightweight products like cigarettes or video games or heavier objects like a case of soda.

Common Pusher Tray Design Common Upfeed Design


Reasons to Utilize Variable Force Springs In POP Displays

  • Inventory Control

    • V-springs are commonly used in trays that push products forward in a controlled manner. Variable force springs incorporated into pusher trays aid in front-facing the product, allowing shelves to appear fully stocked at all times. These trays allow for a more organized store inventory and assist in keeping track of inventory needs. In today’s COVID-conscious environment, this is even more critical as it allows the customer to handle or touch only the item that they want to add to their cart.


  • Product Integrity

    • Variable force springs are designed around the weight of the products they’re pushing. This ensures the product never gets slammed or compromised while being selected. V-springs allow for most products to be pushed at a consistent force, regardless of the item weight.  At Vulcan, we understand the importance of showcasing products within premium retail space. Often, a low lip is needed on the front of the tray to display more of the product. It’s critical to select the correct force spring to ensure the product does not tip over the front lip, which is taken into consideration with every design.
  • Customer Satisfaction

    • V-springs allow for easier shopping for the consumer, as products are displayed in a more organized and aesthetically appealing fashion. Products include cosmetics, health and medicines, beverages, food and anything that can fit into a retail display.


Design Aspects of V-Springs to Consider

  • Force

    • The force of a variable force spring is variable (OK, maybe that was too easy!). When the spring is either extended or retracted, the force changes. With most retail applications, the spring is working in the retracting direction. However, Vulcan also designs springs for both accurate pushing of the product as well as ease of loading. Unlike a constant force spring, v-springs are designed to have a positive gradient change in force. This is required because the load or force changes as product is added or detracted from the tray or upfeed mechanism. A spring that produces less force as it’s extended is said to have a negative gradient. Negative gradients up to 25% are possible. A positive gradient spring—a spring that produces more force as it’s extended, is achievable up to 500%.
  • Shape

    • Unlike constant force springs, these springs are not as tightly wound or uniform in shape. The coil size changes throughout the body of the spring. This change in coil size is what allows variable force springs to be able to output multiple forces throughout their working extension!

  • End Detail

    • Like just about all flat steel springs, v-springs are available in a wide variety of end details including, but not limited to:


  •  Material Selection

    • The most common material is type 301 stainless steel. These variable force springs can handle a variety of environments required by retail customers, including ambient temperature store areas as well as refrigerated and frozen packaging areas. Texture-rolled high carbon steel can be used when a lower cost is required for high volumes; Inconel 625 and Elgiloy are utilized for the most demanding applications, especially in harsh environments—they’re rarely utilized in POP applications.
    • Material thickness generally runs from .002–.031” and tensile strength range from 270,000–310,000 psi.
    • Finally, our standard finish is a deburred edge, but you can request a “round” finish for a smoother edge. Round edge material specifically works great in upfeed systems.
  • Cycle Life

    • The Vulcan Design Guide includes charts that range from 4,000 to 100,000 life cycles, measured as an extension and retraction of either the whole spring or a portion of it. Keep in mind that low design estimates will lead to early failure, while high design estimates make the spring larger and more expensive than necessary. Specifically, for variable force springs, cycle life is difficult to gauge due to the coil size changing throughout the main coil body. V-springs often outlive the life of the display.
  • Mounting Methods

    • Space is often a limiting factor. The Vulcan Design Guide can help in determining the proper material size that will provide the load required while fitting into your mounting space.

Common Spring Mounting in a Pusher Tray


Consider a V-Spring for Your Next Design

Thank you for taking a few minutes out of your busy day to learn more about different design considerations associated with variable force springs. We hope you see the applicability of these springs for the POP industry and beyond and will consider improving your next design with a v-spring.

If you have any questions whatsoever or would like to discuss one of your upcoming projects, please don’t hesitate to call Vulcan to speak with one of our very talented technical salespeople.

At Vulcan, we go “Beyond the Spring” and we’re here to help. Let’s get started today!

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