The diameter design of the round interior door lock handle should fit the palm size of most people to lay the foundation for comfortable grip. When the diameter is too large, it is difficult for people with smaller palms to fully wrap it, and it is easy to slip when exerting force; when the diameter is too small, the hand contact area is insufficient, which will produce a sense of oppression, and long-term use will easily lead to fingertip fatigue. When designing, the differences in the palms of adults and children, men and women should be comprehensively considered, and a range that allows most people to hold it naturally should be selected, which can ensure that people with larger palms can hold it easily, and people with smaller palms can be stable and not slip when exerting force, thereby improving the basic comfort of use.
The design of the grip arc should conform to the natural bending state of the hand to reduce muscle tension when holding. When the fingers hold the handle, the arc should fit the bending trajectory from the thumb to the little finger, so that each finger can be evenly stressed.
People with larger palms are suitable for a slightly slower arc to avoid discomfort caused by excessive bending of the fingers; people with smaller palms are suitable for a slightly steeper arc to prevent the fingers from hanging in the air due to inability to fit. This arc design that fits the physiological curve of the hand allows users to open the door without deliberately adjusting their hand shape, and can complete the operation with natural force, reducing the extra burden on the hand muscles.
In order to adapt to people with different hand shapes, the diameter and arc of the round interior door lock handle can be designed to be adjustable. By replacing handles of different sizes, the use needs of family members of different ages and different hand shapes can be met. For example, the auxiliary handles designed for children have a smaller diameter and a more rounded arc, which is convenient for small hands to hold; the handles for people with larger palms have a slightly larger diameter and a smoother arc, which improves the stability of the grip. This flexible design breaks the limitation of fixed size and allows the same lock to adapt to a variety of usage scenarios.
The ratio of the handle diameter and the grip arc of the round interior door lock handle needs to be coordinated and reasonable to improve the convenience of force. The design with appropriate proportions can allow the palm to form a natural lever when exerting force, and there is no need to exert excessive force when opening the door. If the proportions are out of balance, such as the diameter is too large and the arc is gentle, the contact points between the palm and the handle will be dispersed, and extra force will be required when exerting force; if the diameter is too small and the arc is steep, the fingers will be concentrated and uncomfortable. A reasonable proportion relationship can make the distance from the fingertips to the palm of the hand match the curvature of the arc when holding, making it easier and more natural to exert force.
The design of the surface texture needs to be coordinated with the diameter and arc to further improve the stability of the grip. The surface of the handle is treated with fine frosting or anti-slip texture, which can increase friction without scratching the hand. For handles with smaller diameters, the texture can be slightly denser to make up for the lack of contact area; for handles with larger diameters, the spacing between the textures can be widened to avoid skin discomfort caused by excessive friction. At the same time, the direction of the texture should be consistent with the movement trajectory of the fingers when holding. When the palm turns the handle, the texture can guide the fingers to slide naturally, reducing the risk of slipping, which is especially suitable for scenes where the palm is prone to sweating or moisture.
In view of the use needs of children and special groups, the diameter and curvature design of the round interior door lock handle needs to be more detailed. Children's palms are small, so the diameter should be appropriately reduced, and the curvature should be adjusted to fit the bending state of children's fingers. At the same time, some cute protrusions can be added to the surface, which is not only convenient for small hands to hold, but also can enhance the interest of use. For people with hand disabilities or inconvenient joint movement, the handle diameter can be appropriately increased, the curvature design can be more gentle, and an auxiliary grip can be used, so that the hand does not need to hold tightly, but can be turned by gently leaning on it, which reduces the difficulty of operation and reflects the inclusiveness of the design.
The connection position between the handle and the lock body will also indirectly affect the actual effect of the diameter and curvature design. The connection point needs to be located at the center of gravity of the handle to ensure a balanced feel when holding it and avoid hand crookedness caused by the center of gravity shift. The distance of the handle protruding from the door surface should be moderate, which can not only allow the palm to fully expand, but also avoid affecting the use due to excessive distance. When the thickness of the door is different, the length of the connecting shaft needs to be adjusted accordingly to ensure that the distance of the handle protruding from the door surface is reasonable, so that people with different hand shapes have enough space when holding it, avoiding collision between the hand and the door surface, thereby ensuring that the diameter and curvature design play the due comfort effect.
