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6 Interesting mechanical motion transfer mechanisms you can use in your product design

Written By: 

Arpit jain

Product designing often involves challenges of transferring mechanical motion between different parts of the product. A product can involve different types of motion like horizontal, vertical, radial, circular, see saw, spiral etc. The product designer’s community has to intelligently deal with parameters like space, cost optimization, strength, user comfort, look and feel etc.  A combination of parts and structure designed to perfection work in synchronization to achieve the desired motion.


Have a look at some of the common yet unseen mechanics involved in transfer of motion from the brains of product designers.

Representational Image of Push to Rotate Mechanism in Ball Pen

Fig. 1: Representational Image of Push to Rotate Mechanism in Ball Pen


1.      Ever thought how does the ball pen tip come out and goes in when you rotate the body of the pen?

A commonly used mechanism in ball pens to push out the tip from the body of the pen and vice versa. The mechanism has two parts. Observe the path cut out in the hollow cylindrical pipe in the bottom half. The top half holds the refill or the ink reservoir tightly and fixed inside the bottom half such that the knob is placed inside the path. When we rotate the pen the knob moves along the path and therefore either pushes out or pulls in the refill tip.  

Image Showing Spring and Plunger Mechanism used typically in ding dong bell

Fig. 2: Image Showing Spring and Plunger Mechanism used Typically in Ding Dong Bell



2.      Have a look at the spring and plunger mechanism typically used to generate a to and fro motion or to pull back the plunger to the original position when the external force has been removed. The arrangement shown in the above image is used in the ding dong bell to strike the plunger against an aluminum wall.


Device Imitating Human Jaw Motion used in Electric Beard Trimmer

Fig. 3: Device Imitating Human Jaw Motion used in Electric Beard Trimmer


3.     An interesting and well thought design to almost replicate the movement of human jaw. This mechanism is being used in electronic shavers. The plastic casing rotates in a vertical circular motion around the horizontal axis. Try if you can make out the exact explanation of the motions involved in the design. For more images check out Insight on Electric Beard Trimmer.


Commonly used see saw Assembly used in rocker switch

Fig. 4: Commonly used see saw Assembly used in Rocker Switch

4.      The see saw assembly commonly found inside the rocker switch. A pair of springs, a rocker and a metal strip arrangement does the job. The metal plate has two kinks to stop the rocker from moving away in either direction.


Double Spring Loaded Hammer Assembly in piezo gas lighters

Fig. 5: Double Spring Loaded Hammer Assembly in Piezo Gas Lighters

5.     Now that’s a challenging one. A double spring loaded hammer assembly used in piezo gas lighters to generate a spark of the order of 7kV using the force of thumb. Brain storm to figure out how to convert the force of a thumb to an electric potential of this value. For more details check out the insight of Piezo Igniter.


Potentiometer Viper Imitating Animal Paw

Fig. 6: Potentiometer Viper Imitating Animal Paw

6.      The viper of the potentiometer holding a metal sheet with the brush at the end resembling the paw of an animal is used to connect the resistance track with the conductive track. The bend in the brushes provides an elastic force to stay in touch with the surfaces. It can also be seen as a bridge connecting two surfaces.