Counterweights
Contents |
[edit] Introduction
In engineering, a counterweight is an object that helps provide stability and balance for another system. Counterweights can be found a wide range of applications, such as cranes, bridges, and lifts, where they help to make systems more efficient at load bearing.
[edit] What are counterweights?
Counterweights help support loads when they are being lifted or lowered. For counterweights to work as efficiently as possible, they need to have the right mass and be at the optimum distance from the pivot point. In physics, this is known as the moment, and it is simply the mass of the counterweight multiplied by its distance from the pivot.
For the most efficient operation, the moment of the counterweight must be equal to the moment of the load. This is extremely important, because if the moment of one side is larger than the other, then the dominant side will topple over.
[edit] Examples of counterweights
Some of the first uses of counterweights were in medieval siege engines known as trebuchets. These were huge structures that used a counterweight to throw projectiles that weighed between 100 – 200 lb into enemy fortifications from a distance.
Counterweights are also common in modern vehicles, where they are used on the crankshaft within piston engines to minimise noise and reduce vibrations when the crankshaft rotates.
In lifts, counterweights are particularly important, as they help to lower the amount of energy required to lift or lower the lift car. The counterweight has a suggested weight that is equal to the weight of the lift car when it is at half its maximum capacity.
Counterweights are also used in bridge construction, particularly in bridges that have one platform spanning an area or two that are joined at the middle. These are known in engineering as bascule bridges, but they are commonly referred to as drawbridges. Because of the counterweight, they require very little energy to operate, which means that the bridge can be opened quickly so that boats can pass under.
[edit] Related articles on Designing Buildings
- Abutment.
- Arbour.
- Bascule bridge.
- Bridges.
- Cranes.
- Forklift truck.
- Funicular.
- Gantry.
- Hoists.
- Lifts.
- Lifting device.
- Lifting platform.
- Lifts and Their Special Operating Modes.
- Lifts for office buildings.
- Lift shaft.
- Scour.
- The importance of service lifts.
- The science of lifts.
- Wheelchair platform stairlifts.
--Nathan Massey 14:36, 11 Jul 2017 (BST)
Featured articles and news
Retrofit 25 – What's Stopping Us?
Exhibition Opens at The Building Centre.
Types of work to existing buildings
A simple circular economy wiki breakdown with further links.
A threat to the creativity that makes London special.
How can digital twins boost profitability within construction?
The smart construction dashboard, as-built data and site changes forming an accurate digital twin.
Unlocking surplus public defence land and more to speed up the delivery of housing.
The Planning and Infrastructure Bill
An outline of the bill with a mix of reactions on potential impacts from IHBC, CIEEM, CIC, ACE and EIC.
Farnborough College Unveils its Half-house for Sustainable Construction Training.
Spring Statement 2025 with reactions from industry
Confirming previously announced funding, and welfare changes amid adjusted growth forecast.
Scottish Government responds to Grenfell report
As fund for unsafe cladding assessments is launched.
CLC and BSR process map for HRB approvals
One of the initial outputs of their weekly BSR meetings.
Architects Academy at an insulation manufacturing facility
Programme of technical engagement for aspiring designers.
Building Safety Levy technical consultation response
Details of the planned levy now due in 2026.
Great British Energy install solar on school and NHS sites
200 schools and 200 NHS sites to get solar systems, as first project of the newly formed government initiative.
600 million for 60,000 more skilled construction workers
Announced by Treasury ahead of the Spring Statement.
The restoration of the novelist’s birthplace in Eastwood.
Life Critical Fire Safety External Wall System LCFS EWS
Breaking down what is meant by this now often used term.
PAC report on the Remediation of Dangerous Cladding
Recommendations on workforce, transparency, support, insurance, funding, fraud and mismanagement.
New towns, expanded settlements and housing delivery
Modular inquiry asks if new towns and expanded settlements are an effective means of delivering housing.