The MUJI acrylic ruler is sort of a prized item at my office. Priced roughly at $4, it’s a great conversation piece for us product nerds. Made out of translucent clear acrylic, brittle but structural, folds in two direction from the center, lets you measure angles and distance. What’s really cool is that the center hinge area is also clear, and lets you peek inside its functioning mechanics. There’s a hinge pin located at center, and a spring hinge that is a cog-like shape made out of a flexible plastic(PP) within the frame around registration points. (This is hard to explain.) The spring hinge plastic piece clicks into each little registration points on the outside, stopping at each bump if you wanted to, but also is willing to move onto the next(or previous) bump if you close/fold out with enough force.
What would you call this? I still have yet to research or ask to my fellow designers. For now, let’s say it’s…a v-twist lock. By the title, it’s exactly what it does. It only travels about tenth of the diameter before the lid unlocks itself. The main body has three dimples located on the inner surface of the container. The lid has corresponding three posts that are triangle, and it follows the contour of long surface cut of triangle shape on the outer line. I assume this lid was made for keeping small non-liquid based item such as paper clips or tacks.. There is a magnet embedded in between the lid and on the container, that helps to naturally and smoothly click into place. The ‘V’ shape allows the lid to slide upward on a faster track (imagine a steep valley), as the two triangular dimples meet and guide themselves upward. All in all, a great lock mechanism discovery!
Let us skip over to the subject of living hinges. Before I had known any better in product development learning, I absolutely adored living hinges. I mean, even the name of them makes you wonder what purpose they serve. Basic principle of living hinge is that they are molded to the product itself, meaning it is permanently a part of two products connected together, designed to hinge on itself. They are most commonly found in your spice cabinet—think Cormick’s spice jars that are fairly disposable, or even your shampoo bottle opening caps. Living hinges are molded flat when injection molded, and molded fairly thin so that it creates natural retaining memory.
Product shown above remains a mystery. One of my co-worker, Larry, had brought it up to my attention of this item once I mentioned to him I had started this blog noting all mechanical objects. We’re pondering if it might be a tea strainer or a dysfunctional citrus juicer. Darn tupperware. If only they had molded instructions on the product.
Another look at a bayonet lock. I was fascinated by the detail of this water bottle. Totaling of 3 parts 1)container, 2)citrus juicer, 3)base container. The container is bayonet locked to the citrus juicer, and base container by a thread to the citrus juicer. Lower part of the main container has TWO details shown—see in second photo—of both bayonet lock + thread mold detail. At first glance I wasn’t sure why it was molded or how it was molded…Product as a whole package made perfect sense. The main bottle is injection blow-molded, helping it to keep consistent wall thickness around the thread + bayonet area.
Let’s talk bayonet twist locks. These nifty fixture locks do the trick of locking two parts based on a cylindrical or spherical shapes together. They only require shorter travel distance vs. a traditional, say, a thread would. It does take a bit of assembling at first, as the user would need to eyeball or consciously be aware where the starting position is. The type of lock is widely used in various products such as: camera lens connector, kitchenwares, etc.
So how it works: The female receptor usually has a built-in capital ‘L’ shape with a vertical serif (a pointed flair at the tip). The male pin once positioned on the right side, travels sideways along the vertical arm of L, then slightly pushed upward towards the serif, allowing it to lock into position. The image above shows a a bump featured on the lid and corresponding two bumps on the bowl. Once the bumps reach a point of contact and bypasses each other with a bit of force applied to twisting it to its side, the lid is securely locked in. To disconnect, twist the lid in the opposite direction while making sure that the bump is out of its received corner.
Interesting door lock I found tonight at my church bldg. It’s constructed out of bent sheet metal, totaling of 3 parts. On the left is a sheet that is bent at the very top tip, where it hugs the other part to lock it in place. The other piece on the right (let’s call it the pivoting lock) has an hinge located at the center, allowing it to pivot freely 360 degrees. The position of axis has sourrounding material that looks like its built to create friction, so that whichever position it is placed by the user, the lock is likely to stay in place. The protruding length of metal piece(where my finger is pointed toward) is where user will be able to control the movement and direction. It looks like there is a shaved layer of material that is missing on the lock…so the frame is half-mooed shaped. The top edge(noted in blue) where the frame ends, is the critical area to note. Its positioning directs when it will lock and open. If the blue edge pivots to right direction and surpasses the left frame, it allows the door to open.