Exploring Hydraulic Circuits on Excavators for Attachment Operations

Excavators are indispensable heavy machinery in construction, mining, and various other industries. They owe their incredible versatility in large part to their hydraulic systems, which power a multitude of attachments for diverse tasks. Hydraulic circuits on excavators are designed to provide precise control, flow, and pressure to these attachments. In this comprehensive article, we will delve into the various types of hydraulic circuits used to run attachments on excavators, including the primary circuits and auxiliary circuits. While skid steers are very similar, this article is going to focus specifically on excavator setups. Primary Hydraulic Circuits Firstly, let’s quickly cover the primary hydraulic circuits that are on every excavator – large and small. Every moving function of the excavator like the bucket curl, boom angle, slewing left and right, all require hydraulic power. In this article, we will refer to these as the primary hydraulic circuits. Every machine no matter how old or new will have a hydraulic circuit enabling each of the functions listed below. Bucket Circuit The bucket circuit is the one of the main primary hydraulic circuits on the machine. It controls the movement of the bucket itself. It consists of a pump, control valve, hydraulic cylinder, and associated hoses. The flow and pressure in this circuit are carefully regulated to ensure smooth digging and material handling as well as optimizing breakout force. Boom Circuit The boom circuit controls the upward and downward movement of the boom, allowing the operator to reach different heights and depths. This circuit is essential for excavation and lifting tasks. It usually consists of 2 hydraulic cylinders (depending on the size of the machine), hoses, and a control valve that regulates flow and pressure. Dipper Arm Circuit The dipper arm circuit controls the extension and retraction of the arm/stick, providing precise control over the digging depth. It typically consists of a hydraulic cylinder, hoses, and a control valve. This cylinder is usually located on top of the boom of the machine. Slewing/Swing Circuit: The slewing circuit is responsible for rotating the upper structure of the excavator. It allows the operator to position the excavator accurately. This circuit comprises a hydraulic motor, slewing ring, hoses, and a control valve. This allows endless 360 degree rotation of the excavator. Auxiliary Hydraulic Circuits In addition to the primary circuits, excavators can be equipped with auxiliary hydraulic circuits that enable them to power various attachments. These auxiliary circuits offer versatility and expand the excavator’s capabilities. Just by looking at the machine you can see how many auxiliary circuits it has equipped by looking on the side of the dipper arm/stick. Every circuit is of course going to have 2 hoses, so each set of 2 hoses is one hydraulic circuit. Here are the primary types of auxiliary hydraulic circuits: Single-Acting Circuit: A single-acting circuit provides hydraulic flow in 1 direction only. This is ideal to operate attachments that require hydraulic force in one direction only, such as hydraulic breakers and post drivers. This circuit can often be referred to as a “breaker circuit”. Not many newer machines are fitted with a single acting hydraulic circuit, but older backhoes can be equipped with a single acting circuit only. Double-Acting Circuit: Double-acting circuits are more versatile and can be used with attachments that require hydraulic flow in both directions, such as hydraulic thumbs, grapples, and augers. Think of any attachment that requires 2 movements like open/close, rotate clockwise/anti clockwise – as always needing 2 way flow. Every primary circuit on the machine that we touched on early has double acting flow – to open and close the hydraulic cylinders or slew the machine clockwise or counterclockwise. Note: most double acting circuits can be manually set into single acting mode via a valve block on the machine. This is to use attachments like breakers safely in single acting mode. Coupler Circuit: Coupler circuits are a hydraulic circuit that can be added to machines to operate quick couplers. Couplers let the operator drop off and pick up different attachments without having to leave the machine. Most couplers operate using a hydraulic cylinder to open and close the coupler. They then have a locking mechanism to ensure the attachment can’t fall off in a dangerous position. Coupler circuits are plumbed slightly differently as they often tap into another circuit of the machine to use its hydraulic flow & pressure. This means that they can be easily added to the machine if it is not equipped from the factory. Most couplers will come with a hydraulic kit to be installed on the machine to operate the coupler. When looking at a machine the coupler circuit usually has smaller hoses as it doesn’t require the same level of oil flow as other circuits. They are also usually located on top of the stick shown below: One of the most common mistakes we come across is customers who mistake their auxiliary circuit for a coupler circuit. Because their machine has hydraulics on the stick, they think they can just use that for their coupler. As mentioned above, coupler circuits are plumbed differently, also for safety reasons. They require a solenoid block and control box in the cab in order to only open when the bucket is in the closed position so that the bucket or attachment doesn’t fall off. You can find installation instructions for the Geith Hydraulic Coupler on our website here. Adding An Auxiliary Circuit Adding an auxiliary circuit to an excavator is a lot more complex than adding a coupler circuit. An auxiliary circuit requires a spare OEM valve on the machine’s pump(s) for the hydraulic pressure & flow but also an added method of operating in the cab, like a foot pedal or new joystick/roller. There are companies that supply and install auxiliary hydraulic circuits on excavators, if you are looking to add one to your machine. However, this will be expensive and we would only recommend doing so if it is going to get a lot of use on

5 Ways to Get More Flexibility Out of Your Excavator

Excavators are powerful machines, but with the right attachments, they can become even more versatile and efficient. Whether you’re in construction, landscaping, demolition, or utilities, having the right tools at your disposal can make all the difference. In this article, we’ll explore five essential excavator attachments—Quick Couplers (Hydraulic & Manual), Tilting Buckets, Tilting Couplers, Rotating Couplers, and Tiltrotators—that can help you get more flexibility out of your excavator. We’ll also discuss their benefits, drawbacks, and real-world applications to help you make the best decision for your needs. 1. Quick Coupler – Hydraulic/Manual What is a Quick Coupler? A quick coupler allows operators to easily switch between different tools and attachments without the need to manually unbolt and reattach them. They come in two main types: hydraulic and manual. Quick couplers are now commonplace in the industry and most new machines would be sold with a quick coupler of some sort. For more information about quick couplers and excavator mounting systems specifically, you can read our article here! Benefits: Time Efficiency: Reduce downtime by quickly switching between attachments, such as buckets, breakers, and grapples. Hydraulic quick couplers allow tool changes at the press of a button, making it much faster switching between attachments. Enhanced Versatility: Quickly transition between various attachments, expanding your excavator’s capabilities across multiple tasks. Changing between tools faster also makes it easier to pick up the correct tool for the job at hand. Improved Safety: Hydraulic systems enable tool changes without the operator leaving the cab, reducing exposure to hazardous conditions. Drawbacks: Initial Investment: The most cost effective option is to manually pin the bucket to the end of the excavator rather than having a coupler. Hydraulic couplers are more expensive than manual options, potentially impacting budget allocations. Maintenance Needs: Regular maintenance is necessary to prevent leaks and ensure smooth operation, adding to long-term costs. Another moving part on the excavator, means there is potential for more problem areas and parts that can fail. However, that being said, big name brand couplers are very reliable and should rarely breakdown. Compatibility Concerns: Not all quick couplers are compatible with every excavator model or attachment, so it’s important to verify compatibility before purchase. Installation: If your machine isn’t currently equipped with a hydraulic coupler, it may not have the hydraulics needed to install a hydraulic coupler. This would require a coupler kit with all the necessary parts to install the hydraulic circuit top open and close the coupler. This is specific for your excavator make and model. For more information about installing a hydraulic coupler on your machine, contact us here! Real-World Application: Quick couplers are now a common sight across the industry and in our opinion the efficiency vastly outweighs the cost and they are a no-brainer addition to an excavator. This is why most machines are now sold with a coupler and buckets from the dealership. 2. Tilting Bucket What is a Tilting Bucket? A tilting bucket can usually tilt up to 45 degrees in either direction, allowing for precision in grading, shaping, and other detailed tasks. It’s especially useful in landscaping and projects that require working on slopes or uneven terrain. Using 1 or 2 hydraulic cylinders, the bucket can tilt side to side, rather than staying in the vertical position. Benefits: Precision Grading: Achieve more accurate grading and shaping, essential for landscaping, trenching, and fine excavation tasks. Adaptability on Slopes: Work effectively on uneven terrain without having to constantly reposition the excavator, improving efficiency. This means less wear and tear on the machine’s undercarriage by tracking back and forward and also less mess on the ground that the machine is sitting on. Less repositioning of the machine over time, can lead to a time saving and also increased fuel efficiency. Improved Material Handling: Handle different types of materials more effectively by adjusting the bucket angle to suit the terrain and task. Drawbacks: Added Weight: Tilting buckets can add extra weight, which may affect the excavator’s stability. Higher Cost: These specialized buckets are more expensive than standard ones due to their enhanced functionality. Operator Skill Required: Effective use of a tilting bucket requires experienced operators who can manage the extra degrees of freedom to get the most out of the excavator and attachment. Restricted Applications: Tilting buckets are usually smooth, wide grading buckets and used for final grading etc. This would mean the operator would have to switch the bucket out for s regular digging bucket if they were heavy digging. However the bucket can be used underneath a coupler, meaning that this is not too time consuming.   Real-World Application: Ideal for landscaping, ditch clearing, and construction projects that demand precise material handling, tilting buckets are perfect for achieving the fine details required in custom terrain shaping. Heavy digging and quarry works for example, might not be as suited to a tilting bucket attachment. 3. Tilting Coupler What is a Tilting Coupler? A tilting coupler adds tilting capabilities to any attachment, usually up to 90 degrees. A tilting coupler essentially takes a regular coupler and adds a tilting mechanism in the middle. However it doesn’t use hydraulic cylinders, like the bucket, it unusually uses a rotary actuator. This allows for constant torque and more angle (up to 90 degrees each side on smaller machines). The main benefit of the tilt coupler vs the tilting bucket is the ability to use it to pick up a range of different buckets and attachments. Since the tilt mechanism is in the coupler itself, it doesn’t matter what you pick up, you can tilt it side to side. Benefits: Enhanced Range of Motion: Allows for better control over tool angles, enhancing precision. Space Efficiency: Perfect for projects in confined spaces where frequent repositioning of the excavator is impractical. Versatile Applications: Useful for various tasks, including utility work, landscaping, and demolition. Drawbacks: Complexity: The added mechanical parts increase the likelihood of wear and tear, leading to higher maintenance needs. Cost: Tilting couplers are more expensive than standard couplers, which may