Vertical Plate Clamps provide a safe means of rotating, transporting or turning over plate steel when no lift points exist. There are, however, several criteria that must be considered to maintain safe lifting while using vertical plate clamps. While there are other styles of plate clamps available, from horizontal to non-marring, LGH carries only traditional vertical style clamps. As a result, that is the only style of clamp we will discuss today, and we’ll start with the basics.
How they work:
Vertical plate clamps work with pressure applied onto a set of teeth that rotate into the plate during the lifting sequence. As the eye is raised, it tensions a spring-loaded internal link that torques the jaw into the plate. At this point, the teeth dig into the surface, spreading the load across all teeth in contact with the plate. Once engaged, the teeth grip the plate until the load is safely lowered onto a surface in which the eyelet disengages the spring. The idea is to press the teeth into the plate, creating one singular object.
When working with plate clamps, one primary rule of thumb is that the greater the load, the greater the grip. The stronger the grip, the deeper the teeth bite and the less possibility there is for movement of the plate. This is especially important when it comes to wear on the teeth and the unit itself. In line with the rule of thumb above, clamping tighter minimizes wear of the device.
Tips for use:
With vertical plate clamps, the primary point of emphasis is to ensure proper selection for the task at hand. If you have several different sizes of plate with varying weights, you may require multiple plate clamps to ensure safety. The following are a set of tips to ensure proper loading and minimize premature wear of the lifting device:
- Always select a clamp with the closest WLL (working load limit) to the weight of the plate.
- Select a clamp that has a maximum jaw capacity as close to the plate thickness as possible.
- Avoid lifting a load 20% below the rated capacity of the clamp’s WLL.
- NEVER lift more than one sheet at a time as this can cause damage to the clamp or even loss of load.
- Do not side load a plate clamp. When using hinged hook ring clamps, make sure to derate the clamp according to manufacturer’s specifications.
- When using multiple plate clamps for larger plate, connect each clamp to a spreader bar to avoid angular forces.
- Never lift plate that is heated to a temperature of 250° or greater. Doing so will affect the heat treating of the teeth and cause permanent damage to the device.
- Ensure that the plate you are lifting does NOT exceed the hardness of the teeth on the device. In addition to causing excessive wear to the teeth, the clamp will not generate enough grip on the load
- Consider that friction between the teeth and the plate reduces penetration and causes wear.
Inspection of a plate clamp is quite possibly the most important thing to prioritize once proper sizing selections are made. ASME B30.20 provides a solid guide of criteria to check prior to use.
- Inspect at least every 1-4 weeks, depending on use. Ensure smooth operation prior to each use regardless of inspection status.
- Degrease regularly, removing any grit, dirt and mud. Any contaminants such as those listed decrease grip on the load.
- Lubricate all moving parts with soft grease
- During inspection, check the clamp for the following including, but not limited to:
- Scuffs on cheeks
- Large indents on lifting eye
- Bent hook ring
- Spring deformation
- Hook elongation
- Deformation of pad side
- Pulling of rivet
- Wear on the pin
- Markings on top of mouth
- Teeth that are chipped more than one half the overall width of the tooth *Note: Teeth that are chipped less than one half the overall width are acceptable ONLY if the adjoining teeth are undamaged.
If you have additional questions or need high-quality, inspected, tested, and certified lifting equipment rentals, LGH has you covered. Click to chat with a live rental support specialist or call 800-878-7305 now.