SaferSaw

The “Revamped Double Diamond Design Process Framework” as approached by Dan Nessler in 2016, is the methodology I followed for the process of designing the SaferSaw. After intense research through a literature review and technical analysis, many ideas were considered for the redesign of tree cutting equipment. The research converged to a point that ideation could be conducted from. This point was the portability of chainsaws for building trails and for emergency services, as the bar guide on current chainsaws would protrude from any mounting device.

Many ideas diverged into different sectors of tree cutting services, where safety considerations became an important aspect of the design. Early concepts that stuck were based on the idea of a chainsaw with a moving bar. Both the retracting bar and a rotating bar design were further developed, as the concept of a bar that can be reduced in size would improve portability. It was then realised that kickback, a major injury risk related to the incorrect use of a chainsaw, could be eliminated with these same designs. Another strong idea considered was an exo suit concept that could help prevent kickback on current chainsaws. These three designs were put through a selection process matrix, where the SaferSaw featuring a retracting bar was chosen.

Design developments to be followed from this point include experimentation, form studies, ergonomic reviews, technical design, branding considerations, packaging considerations, form refinement and Engineering considerations.

The Safer Saw’s core engineering focus revolves around kickback elimination and user safety. The key technical aspect is the rapid activation of the retracting guide bar within 1/20th of a second, preventing any contact with the user during a kickback event. This feature is critical in reducing the risk of injuries, particularly those caused by the violent inertial force of traditional chainsaws.

Portability is another pivotal factor, with a weight limit of less than 6 kilograms to ensure ease of use and transport. Regulatory compliance with Australian Standards (AS 2726-1984 and AS 2727-1984) is important, emphasizing adherence to safety guidelines and maintenance requirements.

These safety enhancements should result in a substantial reduction in injury rates. Market positioning and competitive pricing are strategic considerations to encourage adoption, making this innovative chainsaw indispensable for the tree cutting industry. Environmental compliance and user support, including comprehensive training materials, are also vital elements to ensure the product’s overall success.

The SaferSaw has had a well-rounded development path that has evolved into a solid project that intends to solve a social need. Beginning as a “Safer Tree Cutting Device,” early ideas gauged the largest risks involved with wood cutting, including fallen debris, heavy lifting, transport and injuries caused by cuts. Through research from user experience and literature the need for safer cutting equipment making clear. The retractable chainsaw was chosen as it solved multiple issues found common in other cutting equipment, specifically portability and kickback tendencies. The SaferSaw tackled this gap and was designed with respect to the customer wants, with battery power, simple use and in-built safety that does not require extra learnings compared to traditional chainsaws.

SaferSaw showcases a world first retracting guide bar. This innovates from traditional chainsaws that house a solid guide bar that protrudes from the body. In the event of kickback this guide bar flies towards the user and has the capability to strike them, cutting or hitting them with high force as a result. All chainsaws are prone to kickback including the SaferSaw, however with the retracting bar there is no physical force hitting the user.

The retraction happens in the time it takes for the pinion gear to rotate ~5 times. This takes a fraction of a second when this gear is being spun full speed by the motor, which can run at speeds up to 7000 RPM. If it is activated in the event of a violent kickback that is faster than the guide bar takes to fully retract, the chain will not cut the user as the chain driving gear is removed from the chain the instant the chain brake lever is activated. Chain brake devices on current chainsaws stop the chain by grabbing the motor flywheel to stop it in place.

The SaferSaw removes the chain’s driving force altogether by removing its driving gear first, then retracting the bar. Note that it is the same driving gear that rotates from driving the chain to driving the bar.

The SaferSaw can be returned to its cutting configuration by clicking the reverse button, sliding the guide bar back to its cutting position. Once in its cutting position the chain brake lever can be lifted back up, engaging the gear with the chain to cut again.

The Safer Saw will help countless tree cutting services, while providing the market with an innovative chainsaw that eliminates certain injury risks, making current competitors on the market obsolete.

Tree cutting equipment such as chainsaws require high amounts of focus, ability and training to operate, yet have been following the same design for over 70 years. High safety risks are still present in the design of the chainsaw, with kick back, the violent inertial force of the chainsaw directed towards the user’s head, only lessened with a ‘chain brake’ that stops the chain rotating while the entire saw still has the potential to hit the users face.

With a fatal injury rate of 132 per 100,000 - Logging Workers have the most dangerous job in the world. The SaferSaw is indispensable for arborists navigating challenging tree canopies, emergency responders in harsh weather and trail builders charting dense foliage. SaferSaw sets a new industry standard preventing a leading cause of chainsaw accidents. In addition to the safety features of the design, SaferSaw is also exceptionally portable owing to its retracting guide bar, making it the most compact chainsaw in its class.

The added benefit of this design is the reduced size of the Safer Saw when it is in its retracted state. Portability is significantly easier with half of the length removed, so no guide bar is protruding, making it the most compact chainsaw in its class. This design will likely challenge current guidelines outlined by the Australian Standards, AS 2726-1984 ‘Chainsaws - Safety Requirements’ considering the design, construction and mechanical requirements of the chainsaw and AS 2727-1984 ‘Chainsaws - Guide to Safe Working Practices’ maintenance schedules, hazards, protections and safety operations.

SaferSaw promises to transform chainsaw technology, creating a new expectation for safety, innovation, and convenience.

The handle has been separated from the main body so majority of the plastic can be recycled at its end of life. The prototype has been designed to use a rubber bicycle grip on the handle that can be customised for the user’s style and replaced when the rubber wears out. The production model may be the same or overmoulded, where the handle can then be replaced if the rubber wears out, which is only a small portion of the overall plastic amount that can be recycled. If the product was one piece, none of it could be recycled due to the overmoulding infused into the plastic.

Large bolts are used with a simple flathead/Phillips head combination so they can be unscrewed with any screw driver and any flat item such as coins and butterknives. This encourages the right to repair with ease of disassembly for households that do not have tools as they can use a substitute device. This is far easier than most tools on the market that use tiny screws with unique drive heads that cannot be loosened unless a specialty tool is used.

A SolidWorks Sustainability report was conducted on one side of the main body casing to determine the environmental impact of the material it would be manufactured in. ABS PC was chosen as the baseline for its common use in power tools due to its hardness, impact strength and heat tolerance. This was compared to standard ABS which requires less energy to produce and costs less. ABS PC would still be chosen for the production model for its strength characteristics impact resistance and ease of machineability. ABS PC is also recyclable at its end of life.