Design and construction of hydraulically operated Spring Stiffness Measuring Machine

Mr Moshood, welcome to this educational site ISC.

Hydraulically operated Spring Stiffness Measuring Machine is used for checking the stiffness of the various types of springs. Different types of the springs are manufactured for use in various industries. There is a need of a stiffness measuring machine for assessing the status of the spring.

These machines are required not only in the industrial arena but useful in laboratory environment for development of strong springs.

There are many technical papers which give a good detail of this machine and you can learn the basic steps and fundamentals of this machine. I have gone through one such paper which is quite exhaustive and the reference is -

International Journal of Emerging Engineering Research and Technology
Volume 2, Issue 7, October 2014, PP 184-190
ISSN 2349-4395 (Print) & ISSN 2349-4409 (Online)

This is available online free and you can go through it.

For your convenience, I am giving the link of the webpage here -
http://www.ijeert.org/pdf/v2-i7/24.pdf

Spring stiffness measuring machine is designed and constructed by using the hydraulic principle. It mainly consists of a small cylinder, large cylinder, bourdon tube gauge and deflection scale.

The base is built with the use of frame construction. Mounting of other components is done in it. Dimensions of base depend on dimensions as well as the design of other components. The resulting frame will have a centre support. There will be a slot of 2 cm spacing in the centre construction. To and fro movement of a small cylinder depending on the requirement will be fulfilled inside it. Large cylinder is fixed rigidly on one side. Bolt and nut are used to fix these cylinders.

The guide mainly comprises of the centrally placed hollow pipe. A spring placed can open the pipe half and then close it. The height of the constructed guide can be adjusted by loosening and tightening of the nut. It can also be removed in case it is not required.

Assembly-
- Mark the centre of the side of the plunger pump housing which has a maximum cross-section area and four holes.
- Weld the pressure cylinder circumferentially on the plunger pump housing. Two holes should be out and two holes should be inside its coverage.
- Next, the reservoir cylinder is welded on the pressure cylinder and plunger pump housing.
- On the side that isn't tapped, mark the end block's centre and mark a circle.
- The things that were assembled formerly are placed on the circle. Pressure cylinder is circumferentially welded on the end block.
- Fitting is done with bolt and nut on the other end.
- Retracting spring is inserted on the piston rod. This assembly is enclosed into the pressure cylinder followed by tightening of the guide to the end block.
- With the help of bolts, the upper and lower wings are fitted to the end block.
- The entire assembly is placed above the stand followed by inserting of the valves, washers and balls in the plunger pump housing.
- Reservoir cylinder is filled with hydraulic oil. The hydraulic spring stiffness measuring machine is assembled in this way.

The working of hydraulic stiffness testing machine is based on PASCAL`S LAW. This law is mentioned as '' PRESSURE APPLIED AT ANY POINT ON ANY CONFINED LIQUID IS TRANSMITTED EQUALLY TO ALL OTHER POINTES''. The same principle is being used in hydraulic presses also.
Using this machine is having many advantages like the spring can be tested without any damage to the spring. Springs of different diameters can be checked.
There is a nice paper published in the journal WJERT. The title of the article is HYDRAULIC SPRING TESTING MACHINE. The web site of the journal is www. wjert.org. The link for the same is www.wjert.org/download/article/18122016/1486983938.pdf.
You can try and read this paper which discusses the entire process very nicely.