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Compact Hydraulic Single Axis Knee
M0703 Dolphin

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Activity Level and Body Weight Limits

Activity Level and Body Weight Limits
Activity Level Body Weight Limits
3~4 100kg

Giving you voluntary control to let you walk.

Product Features


The Dolphin is a knee joint designed for to give users who weigh up to 100 kg voluntary control. It supports dynamic motion for active walking and light exercise.

Lightweight, Slim, and Compact

The Dolphin's main structural components use an aluminum alloy for weight reduction. Since it's slim and compact, it can be covered with a sporty cosmetic covering to suit users who are slender, including women and children.

Extremely Stable Knee Axle Position

The Dolphin is designed with the knee axis positioned toward the back, enhancing stability during the early stance phase. Voluntary knee joint control can be exercised using less muscle strength.
The Dolphin is ideal for users who are already proficient with voluntary-control knees, such as users who have been keeping the brake sensitivity of their load brakes to a minimum as well as current users of floating single axis knees.
The gate of users who are in voluntary control looks more natural than is possible using stance-phase controls.

A Hydraulic Cylinder to Help with Pre-Swing


At our company, "flexion of the knee joint which takes place at the final stage of the stance phase" is referred to as "pre-swing," short for "preliminary flexion of the knee joint towards the swing phase".

The ease of Pre-Swing performance influences the smoothness of the gait. Knee joints that provide an easy pre-swing make the lower leg feel lighter and allow for smoother transitions to the swing phase. On the contrary, a difficult pre-swing makes the leg feel heavy when swung, making it impossible to achieve a smooth transition to the swing phase. The characteristics of the knee joint's hydraulic cylinder have an effect on pre-swing. With hydraulic cylinders that generate a strong hydraulic resistance during flex initiation, this strong resistance can hinder motion and make pre-swing difficult. The large majority of conventional hydraulic knees have had difficulty with pre-swing, causing them to be poorly evaluated by amputees ("oil pressure knees make knee-swing heavy") and to be avoided as a result.

Characteristics of Hydraulic Cylinders

Less hydraulic resistance during the start of bending results in smoother use. Because the Dolphin has an easy pre-swing, swinging the leg feels light and easy, and transition to the swing phase can occur smoothly. Afterwards, as the bend angle increases, the hydraulic pressure also slowly increases, matching the user's walking speed and controlling heel kick.

Making Adjustments

Adjusting Flexion Resistance
Flexion resistance on the Dolphin can be set by rotating the hydraulic cylinder by hand without the need for any special tools. Looking at the Swan from behind, turning it clockwise increases flexion resistance, and turning it counter-clockwise decreases flexion resistance. The maximum flexion resistance of the Dolphin is the highest among all our company's products. This joint has outstanding gait adaptability that makes it ideal for users who engage in active walking and light exercise.
Adjusting Extension Resistance

Adjustment part of Flexion Resistance

Extension resistance can be adjusted by using a six-sided wrench to turn the adjustment screw on the upper part of the hydraulic cylinder. Turning the adjustment screw clockwise increases extension friction, and turning it counter-clockwise reduces extension friction.

The Extension Assist Spring

The Dolphin's extension assist spring is built into the hydraulic cylinder.

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Product Specifications

M0703 Product specification table
Module Number M0703
Product Name Dolphin
Activity Level 3~4
Body Weight Limit 100 kg
Weight 495 g
Overall Length 184 mm
Overall Width 54 mm
Material Aluminum Alloy
Swing Phase Control Mechanism Hydraulic Cylinder
Stance Phase Control Mechanism
Maximum Bend Angle 180°

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The Origin of the Nickname

Until this point, Lapoc product nicknames had been chosen through internal company submissions, but with the Dolphin, for the first time, ideas were submitted by the general public, and from them a nickname chosen. Through the "New Product Naming Campaign," notices appeared extensively in flyers and on the company website, soliciting ideas not just from industry members but from the wider general public. The final submission count was 477. An unexpectedly large number of submissions were received, considering the relatively short contest time of one month from announcement to deadline and the nature of the product.

The nicknames BASS and Swan had already been given to knee-joint products, and what they had in common was that they were "names of living creatures." It was impressive how many submissions consisted of the English name for living creatures, made by people aware of these two products. Of course, there were also many creative and unique names inspired by the shape and color of the product in addition to the winning animal name, and we had a great time looking over the submissions. Company staff carried out the selection process, but making a decision took a lot of time. In the end, "Dolphin" was chosen to represent that creature's dynamic strength and graceful movements.

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