Demolition Hammers Information

Figure 1: Jackhammers. Source: Pixabay

Whether tearing out old tile or demolishing a worn-out structure, demolition hammers are there to get the job done. Demolition hammers come in different sizes and shapes but are tools used for controlled demolition. While other tools are used for building, demolition hammers are designed to clear out old structures and materials to make way for something new. By converting a structure into smaller, more manageable pieces, other equipment can then remove the old material in a much easier and more manageable way.

Theory of Operation

Demolition hammers, also known as jackhammers or breakers, are specialized power tools designed to fracture hard materials such as concrete, masonry, and asphalt. Their effectiveness lies in their ability to deliver rapid, high-energy impacts to the material they are used on.

At the heart of many traditional demolition hammers is a pneumatic system. This system relies on compressed air, which is initially generated by an external compressor. Once directed into the hammer, this air moves into a cylinder. Within this cylinder, a piston rapidly oscillates. As the piston rises, it draws in more of the compressed air. On its downward stroke, this air is expelled, propelling the piston into a chisel or bit, which then delivers the powerful impact required to break materials.

The chisel or bit plays a crucial role in this process of energy transfer. Crafted from hardened steel, it is the direct point of contact with the material targeted for demolition. These components come in a variety of shapes and sizes, each designed for specific tasks. The bit must be incredibly hard and tough to withstand the beating it takes.

For ease of use, demolition hammers are often equipped with user-friendly interfaces. A handle allows for firm grip and maneuverability, while a trigger controls the onset and cessation of the hammering action. Modern designs often prioritize ergonomic handles, reducing user fatigue during prolonged operations. Larger demolition hammers are mounted to mobile pieces of equipment.

In a typical application, a user positions the chisel or bit against the intended material. Engaging the trigger initiates the rapid piston action, with the chisel or bit delivering forceful impacts. Adjusting its angle and position allows users to break through various materials efficiently. The energy from the chisel enters the material being demolished and ideally is converted into fracture energy, breaking the material.

It's worth noting that while many demolition hammers utilize a pneumatic system, alternatives exist. Electric and hydraulic-powered hammers, for instance, employ electric motors or hydraulic fluid, respectively. All of these demolition hammer types will be discussed in more detail later on. Regardless of the energy source, the primary goal is consistent: converting energy into powerful impacts to achieve effective demolition.

Figure 2: An excavator-mounted hydraulic jackhammer. Source: Public domain

Specifications

Demolition hammers, like other power tools, have a range of specifications that can determine their suitability for particular jobs and their overall performance. Here's a list of common specifications you might find when evaluating or purchasing a demolition hammer:

Power Source

Demolition hammers convert large amounts of energy into fracture energy. The source of this energy varies and can be pneumatic using compressed air, electric using electricity from a power outlet or battery, or hydraulic using a pressurized hydraulic fluid.

Impact Energy

Measured in joules (J) or foot-pounds (ft-lbs), this specification represents the energy of each blow the hammer delivers. Higher impact energy usually means the hammer can break harder materials more effectively.

Impact Rate

Measured in blows per minute (BPM) or impacts per minute (IPM), impact rate indicates how many times the hammer will strike in one minute. A higher BPM often translates to faster work but may not always mean more effective breaking. High impact rate and high impact energy together result in a large amount of power being delivered to the structure and thus a higher demolition rate.

Tool Holder/Chisel Type

Different demolition hammers can hold different styles of bits or chisels. This specification describes the type of bit or chisel the hammer can accommodate, such as SDS-max or hex.

Weight

The overall weight of the tool is a very important specification. The weight can greatly affect user fatigue and maneuverability.

Vibration Control

Some hammers come with built-in systems to reduce vibration, making the tool more comfortable to use over extended periods.

Noise Level

The noise output from a demolition hammer is measured in decibels (dB). This specification is important for user comfort and safety, especially in environments where noise pollution is a concern.

Durability and Warranty

Materials used in construction and the warranty period offered by the manufacturer can give insights into the tool's expected lifespan.

When considering a demolition hammer for purchase or use, it's essential to understand these specifications. They can help determine the tool's appropriateness for a given task and offer a comparison point against other models.

Figure 3: Worker using a jackhammer. Source: Pixabay

Types

Demolition hammers are classified based on their design, size, intended use, and the mechanism they employ. Here's a breakdown of the main types of demolition hammers:

Pneumatic Jackhammers

These demolition hammers use compressed air to drive an internal hammer mechanism. They are standard tools on construction sites and are typically used for breaking concrete and other hard materials. Pneumatic jackhammers are generally larger and more powerful than other types.

Electric Demolition Hammers

These jackhammers are powered by electricity, either from a power outlet (corded) or a battery (cordless). They are suitable for a variety of tasks, from breaking tiles and masonry to more demanding jobs like breaking concrete or asphalt.

Electric demolition hammers can also come in rotary hammer and hammer drill variations. Rotary hammers can drill and hammer simultaneously. A piston connected to a crankshaft hammers the bit. They are generally used for drilling into hard materials like concrete and can often be used in a hammer-only mode.

Hammer drills are more suited for drilling than pure demolition. They combine rotation with a hammering action to drill into hard materials. Hammer drills require the rotary action to load a spring for the hammer action and are typically not as powerful as rotary hammers.

Hydraulic Demolition Hammers

These hammers are powered by hydraulic fluid, often from a separate power pack or a piece of construction equipment. Hydraulic demolition hammers are used in heavy-duty applications, like roadwork or large construction projects. They are typically larger and designed for heavy-duty tasks.

Mini Jackhammers

These hammers can be electric or pneumatic. They are smaller versions of the standard jackhammers. Ideal for tight spaces or less intensive tasks like tile removal, these mini jackhammers are much easier to maneuver.

Breaker Hammers

Usually electrically powered, these demolition hammers are designed specifically for breaking concrete, stone, and masonry. They do not rotate like rotary hammers or hammer drills. They can range in size from medium to large.

Chipping Hammers

Operation of these demolition hammers can be electric, pneumatic, or hydraulic. They are commonly used for chipping away materials, cleaning welds, and other tasks requiring precision rather than brute force. They are typically smaller and more maneuverable.

When choosing a demolition hammer, it's crucial to match the type of hammer to the specific requirements of the job. Factors such as power source, mobility, the intensity of the task, and the material to be broken all play roles in determining the most appropriate tool.

Figure 4: A military engineer breaks apart the asphalt with a jackhammer. Source: Public domain

Features

Demolition hammers come with a variety of features, each designed to improve performance, user safety, and comfort. Here are some of the key features you might find in modern demolition hammers:

Variable Speed Control

One key feature to give the user control over the demolition process is variable speed control. This feature allows the user to adjust the speed of the hammering action, offering greater control over the demolition process. Varying the speed allows for the varying of the energy being put into the material being destroyed.

Vibration Control/Reduction

Vibration can be quite intense from a demolition hammer. Features to control or reduce the amount of vibration transmitted to the user help to minimize fatigue and potential long-term health issues.

Soft Start

This feature ensures the hammer doesn't start at full power immediately upon being turned on, reducing the initial shock and providing better control.

Ergonomic Design

Handles and grips designed for comfort can make a big impact on a jackhammer’s ease of use. Properly designed, these features reduce user strain during prolonged use.

Dust Extraction and Management

Features like dust collection ports or integrated vacuum systems help manage and reduce dust during operation, providing a cleaner work environment and reducing health risks. Many materials can become powdered and inhalable during demolition and can contain potentially hazardous compounds.

Anti-dry Fire Mechanism

This feature prevents the hammer from firing when there's no load, reducing unnecessary wear and tear on the tool. If the tool is fired without a load to absorb the energy, the tool itself must absorb the energy, which causes unnecessary strain and damage.

Quick-change Tool System

This useful feature allows for rapid and easy changing of bits or chisels without needing additional tools.

LED Indicators/Lights

Oftentimes, it can be difficult to see the work being demolished. LED indicators and lights illuminate the work area or indicate tool status, such as power, overheating, or maintenance requirements. All of these uses give the user more control and awareness of the work being performed.

Overload Protection

A potentially money-saving feature, overload protection can be critical to a tool’s longevity. This feature protects the motor and other components from damage due to excessive load or use.

Noise Dampening

Jackhammers can be incredibly noisy. Features that reduce the noise output of the hammer can be highly beneficial in noise-sensitive environments.

Lock-on Button

A lock-on button lets the hammer operate continuously without needing to hold the trigger constantly. This feature must be incorporated safely so that it does not do more harm than good.

When selecting a demolition hammer, it's essential to consider which features are most relevant to the intended use. Factors like the environment, duration of use, material type, and user experience can help determine which features are most valuable for a particular job.

Figure 5: A lone jack hammer. Source: David Lally/CC BY-SA 2.0

Manufacture

Manufacturing demolition hammers involves a combination of material sourcing, machining, assembly, and quality control processes. While specific manufacturing steps might vary depending on the brand, model, and region, the general process can be outlined as follows:

Material Sourcing

Materials like steel, aluminum, plastic, rubber, and electronic components are sourced. The quality and specifications of these materials often determine the hammer's durability and performance. Any material going into a demolition hammer must be of exceptional quality due to the durability requirements.

Machining and Shaping

Metal parts, such as the casing, cylinder, and piston, are shaped using machining processes like milling, turning, and drilling. The chisel or bit is forged from high-grade steel and then heat-treated to enhance its durability and hardness. Plastic and rubber components, like handles and casings, are usually molded using injection molding techniques.

Assembly

The internal components, including the piston, cylinder, and motor (for electric models), are assembled. Electronic components, such as switches, speed controllers, and sensors, are integrated and wired together as needed. For pneumatic hammers, the air inlet and hoses are attached. All connections must be mechanically strong so that vibrations will not weaken the connection over time. The outer casing or shell is then attached, securing all internal components.

Testing and Quality Control

Each unit undergoes rigorous testing to ensure functionality, safety, and efficiency. Tests can include operational tests, electrical safety tests, and performance evaluations under different conditions. Random units from each batch are often subjected to additional quality checks to ensure consistent production standards. Any defects identified lead to adjustments in the manufacturing process to prevent future issues.

This overview provides a general idea of the manufacturing process, but it's worth noting that specific steps and techniques can vary based on the manufacturer's practices, technological advancements, and the specific model of the demolition hammer.

Figure 6: Worker using a jackhammer. Source: Pixabay

Applications

Demolition hammers are versatile tools designed primarily for breaking and demolition tasks. Their applications span various sectors, from construction to renovation and more. Here are some of the main applications for demolition hammers:

Concrete Demolition

It is hard to find a more perfect application for a demolition hammer than concrete demolition. Breaking up concrete slabs, floors, and foundations can be made much easier with the use of a demolition hammer. Removal of concrete structures like walls, beams, and pillars is also a common application.

Roadwork

Breaking up asphalt or concrete roads for repair or replacement is another common application of demolition hammers. Creating trenches or holes for utilities or road maintenance is also aided by the use of jackhammers.

Masonry and Brickwork

Removing brick or stone walls is much faster with demolition hammers. Demolishing masonry structures like chimneys or pillars also needs a lot of energy making demolition hammers common tools of choice.

Tile Removal

Removing tiles from floors or walls during renovation projects is commonly performed with a chisel bit and a demolition hammer. The impact of the hammer often releases the tile from the subfloor while keeping the tile mostly intact.

Trenching

Creating trenches in rock or hard ground for utilities like water, gas, or electrical lines is greatly helped by the use of jackhammers.

Mining and Quarrying

Breaking rock or ore in mining operations requires a great deal of energy. Creating access paths or removing unwanted rock layers in quarries is another application for demolition hammers.

Renovation and Restoration

Carefully removing sections of buildings for renovation without affecting surrounding structures requires strong tools that can be carefully controlled. Taking down parts of historical buildings for restoration purposes may require a jackhammer as well.

Welding Cleanup

Chipping hammers are used to remove slag or excess weld material after welding operations.

Emergency Rescue Operations

Breaking through walls, floors, or other barriers during rescue operations, especially after natural disasters like earthquakes, can require the speed and control of demolition hammers.

While these are some of the primary applications, demolition hammers are employed in various other tasks requiring the breaking or removal of hard materials. The choice of a specific type of demolition hammer and its specifications often depends on the nature and scale of the application.

Figure 7: A hydraulic jackhammer mounted on a mechanical excavator. Source: Smuconlaw/CC BY-SA 3.0

Standards

Demolition hammers, like many power tools, are subject to various standards to ensure safety, reliability, and performance. These standards are often developed by recognized standards organizations and can vary by country or region. Here are some of the key standards and general areas they may address:

  • IEC 60745 (International Electrotechnical Commission)
  • ISO 28927 (International Organization for Standardization)
  • EN ISO 5349
  • EN 62841

Some of these standards ensure that the tool is safe for use, addressing issues like electrical safety, mechanical safety, vibration levels, and more. Other standards ensure that the tool meets certain performance benchmarks

Some of these standards are for hand-held motor-operated electric tools. Various parts deal with specific safety requirements for different tools, including hammer drills. Other standards focus on the measurement of vibrations at the handle. They have parts specific to different tools, ensuring they don't exceed certain vibration limits.

Ergonomic standards also relate to the design and operation of the tool to ensure it can be used comfortably and without causing undue strain or injury. EN ISO 5349 for example deals with the measurement and evaluation of human exposure to hand-transmitted vibration, relevant for tools like demolition hammers.

Manufacturers typically need to ensure their products comply with the standards of the countries or regions where they intend to sell. It's always a good idea for consumers and professionals to be aware of these standards, as they can provide assurance of a tool's safety and quality.

References

Ronix—How To Use a Jackhammer Safely + Different Types

Rental Depot Boston—Top 3 Uses for A Demolition Hammer

Kisiel Hire—What Are Demolition Hammers Used For?

Family Handyman—Rotary Drill vs. Hammer Drill: What’s the Difference?

Rentalex—How Are Demolition Hammers and Rotary Hammers Different?

KisanKraft—Different Types of Demolition Hammers and Uses

HowStuffWorks—How Jackhammers Work

ExplainThatStuff—Jackhammers (pneumatic drills)

Ferrovial—What is a jackhammer?

Related Information

GlobalSpec—Answering the air hammering challenge: A test case for innovation

GlobalSpec—New line of hydraulic hammers launched by Takeuchi


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