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Forces of inertia and momentum become much more dangerous when animal laboratory equipment is mounted with casters. Many primate cages, or animal transfer carts, shake and vibrate due to the activity of inhabitants. Invariably, such motion can lead to the inadvertent movement of carts or equipment. This creates unwanted travel and potential damage. Since safety is the first priority for both the laboratory technicians and the subjects under their care, it is best to consider the types of brakes most suited for casters on any mobile equipment in the animal science industry.

The higher the load capacity of casters, the greater the need to have firm brakes on casters. Brake options are important to check against the load’s momentum and add a safety dimension with heavier equipment, such as ventilated racks or primate cages. Caster brakes come in a variety of styles and use. Always consult with the caster manufacturers’ engineers, designers, or technicians about your specific casters and brake options. For heavy duty applications, the brake options include tread lock brake and total lock brake. A tread lock brake ensures that the wheel is locked firmly against any rolling force that may initiate movement. Tread lock brakes engage easily with a toe activated mechanism that locks the wheel from rolling. The toe activated brake features positive engagement facilitated through a rubber-faced plate that can be used against a variety of wheel tread material. Most tread lock brake kits are also field installable to enable the installation of locks once casters are already in use. Installing brakes should not be an afterthought, but designed in the construction of the caster at the outset.

The better brake option on most animal cages and racks is the total lock brake system. It ensures that both the wheel and swivel head of the caster are locked simultaneously. Total lock brakes provide the most secure option against load movement or momentum. Total lock brake options are factory manufactured when the caster is created and, as such, offer optimal protection from a safety perspective as well.

Brakes on casters must be maintained and regularly inspected for proper functionality. If brakes slip due to worn or damaged wheels, the wheels should be replaced immediately and brake functionality retested. During inspection, a check should be done to ensure that the swivel head is firmly locked in place and that the wheel does not turn at all. While heavy duty casters are not easily moved or maneuvered, the slightest shift in load or unanticipated movement by larger animals can initiate an unstoppable momentum that can be a menace in the laboratory or animal housing environment. Always check with the manufacturer for the proper handling of heavy duty casters on primate cages, large ventilation carts, or animal transfer stations.

For lighter duty applications, such as utility service carts, small animal cages, or mobile work stations, side lock brakes are used on casters to securely hold the equipment or mobile stands. Side lock brakes generally use a hub compression system of applying a positive friction force against the hub of the wheel. This is facilitated by compressing one side of the fork leg of the caster against the hub of the wheel with sufficient force so as to stop the wheel from rolling. A side mount metal foot pedal actuates this teeter-totter movement and applies a gripping force by pushing one side of the caster leg onto the wheel. The pedal is designed to be foot activated with an easy press-on or press-off activation. This type of brake is well suited for light duty laboratory applications where the primary purpose of the laboratory cart or equipment is to keep it stationary. Brakes on casters facilitate added care for both animals and support staff in research environments.

Brakes on casters optimize operational safety, security, and flexibility of equipment used in the animal science industry.

Mike Titizian, President, Colson Casters Limited, Canada. titizian@colson.ca www.colson.ca

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