Finding the Right On-Board Scale for Your Application
The right scale system will help you maximize your loads, reduce costs associated with overloading, and help you realize the full potential of your vehicle and fleet to make a profit.
Electronic on-board scales are not new. They were introduced more than 30 years ago into trucking applications where monitoring gross vehicle or payload weight was necessary; however, platform scales were not readily available. Over the years, improvements were made to these early electronic on-board scales. Load cells were improved and specialty load cells were developed for fifth wheels, center hangers, single points and most other types of spring suspensions. Strain gage-based air sensors were added for an increasing number of air ride suspensions and suspension transducers for spring suspensions. Hydraulic sensors were designed for vehicles equipped with hydraulic lift cylinders. Today, on-board scales can be installed on any truck or trailer with air, spring or mixed suspensions.
The Benefits of On-Board Scales
Based on this product evolution, the applications for on-board scales are rapidly expanding and are found in every trucking industry. Currently, organizations using on-board scales realize benefits far beyond just monitoring gross vehicle weight to avoid overweight fines. Given the high cost of time and equipment, on-board scales have a dramatic impact on the efficiency and profitability of operating a truck. On-board scales allow you to:
Optimize residential and commercial vehicle efficiency by hauling the maximum legal payload on every trip to the landfill or transfer station without going to a platform scale
Eliminate overweight fines
Load transfer trailers to the maximum legal weight quickly at the loading point, without waiting in scale lines or driving to the nearest platform scale
Eliminate travel to certified scales
Reduce maintenance costs and increase vehicle life by hauling loads that the vehicle was designed to carry
Increased safety by keeping weight within legal limits and allowing braking distance to remain constant and tracking around corners to be more predictable
Eliminate liability exposure due to increased braking distance from overweight vehicles
Measure commercial or recycling pickup weights to optimize pricing or recycling rebates
Improve customer service by providing individual pick-up or container weight information to better assure your commercial customers that they are being billed fairly
Increase revenue by more accurately charging individual customers on heavy load pickup and delivery operations
Increase driver retention by assuring a safe load, no exposure to overweight fines and reducing the amount of time it takes to get a correct load
Improve operation efficiency by recording weights, load cycles, dump cycles and route/service times. With the increasing use of on-board computers, wireless communications and GPS equipment, weight information can be collected and transmitted real time back to the home office
When waste operations consider the previously mentioned benefits obtained from on-board scales, they typically calculate their payback to be from three to 12 months. This will become increasingly important in the future as the cost to haul without on-board scales increases due to the following industry trends1:
Increasing competition and the need to improve efficiency and reduce costs
Increasing enforcement of overweight regulations
Increasing need to reduce liability exposure
Increasing difficulty finding and retaining competent drivers
Increasing demand for more information
Increasing use of on-board computers, wireless communications and GPS equipment
What Type of Scale System Should You Invest in?
That depends on your objective and which benefits you are trying to capitalize on. There is not a single solution that works for everybody. Choosing the right solution for the right application will allow you to realize your intended benefits while avoiding the long-term performance and maintenance headaches caused by selecting a system that is not suitable for your operation.
On-board scale systems available today include: body scales, front fork scales, roll-off scales, deflection transducers, and air sensors. Body scales, front fork scales and shear pin load cells used in roll-off scales directly measure the load and are proven to be the most accurate over an extended period of time. Secondary measurement devices, including deflection transducers and air sensors, estimate weight based on a secondary measurement such as vehicle suspension deflection or air bag pressure. These devices are more susceptible to outside influences and therefore require specific loading operation and maintenance practices.
Body scale load cells are a tried and true method for measuring the gross vehicle, net payload and individual pickup weights. They have been used for years on tipping and fixed refuse bodies. They require little maintenance and after calibration provide a high degree of accuracy without driver involvement.
Front Fork Scales
Front fork scales are also an accurate weighing solution that require some driver interaction to achieve the weights. Front fork scales work by weighing the individual bins on the route. Different options are available to achieve the weights; manual, where the driver pauses the bin midway twice during the dump cycle and records the bin loaded and the bin empty after dumping, or weigh-in-motion, where the weight is captured during the dump cycle without having to pause. Both methods require the driver to follow procedures to achieve the highest degree of accuracy. The system records individual pick up weights and total net payload weight. This application is ideal for route audits.
The roll-off and dump truck scales use a combination of shear pin load cells and a hydraulic sensor to weigh the load. These systems are extremely reliable and durable, providing accurate weights with little maintenance.
Deflection transducers are a low cost option to load cells for measuring gross vehicle weight. They are mounted on the axles or suspensions of the vehicle and measure the deflection of the axle or suspension under load to achieve the weight. Under the right conditions and depending on application objectives they can provide a useful measurement, but are susceptible to outside influences including loading environment and driver performance. They also require more maintenance due to their mounting locations and a more systematic calibration schedule to maintain accuracy since they are approximating weight via a secondary measurement.
Transfer Station Solutions
Transfer vehicles use a variety of solutions depending on the suspension type. These include fifth wheel load cells and center hangers for spring suspensions on the tractor and trailer, air sensors for air suspensions or a combination of both. These solutions allow the vehicles to maximize their load before they leave the pit. This saves the operation time lost on vehicles being overloaded or underloaded when crossing the platform scales requiring the vehicle to repeatedly return and reload.
Match the Best Solution to Your Needs
You’ve identified your goals and researched scales—now it is time to purchase your system or systems. Choose a scale company that offers a wide variety of on-board weighing solutions so you are able to match the best scale solution to your specific goals and objectives. This way you can select a customized weighing program for your specific operation. The right scale system will help you maximize your loads, reduce costs associated with overloading, and help you realize the full potential of your vehicle and fleet to make a profit.
Eric Elefsonis the Director of Marketing and Sales for Vulcan On-Board Scales. He has been involved in the on-board weighing industry for 13 years. Prior to that, he had 18 years in the industrial automation and control industry. Eric can be reached at (253) 872-1910 or via e-mail at [email protected].
Source material includes: increased and changing competition in the market, receiving locations, ie mills, etc. requiring more strict adherence, customer feedback and increased coverage of weight and on-board automation in industry publications.