Specification for vibration machine for standard cement mortar cubes
Test Standard: IS 10080 (1982)
This is specifies the requirements for the vibration machine used in casting of cement mortar cubes of size 70.6 mm. The vibration will consist of the machine and a vibrator, housing the revolving shaft with the eccentric supported on four springs, which are mounted on a bed of the assembly channel.
A pulley carrying motor (3/4 hp, 2 800 rpm) will be coupled through an endless belt to the vibratory revolving shaft. A belt guard will be provided.
The machine can be fitted with a time switch.
The vibrator shall be constructed to comply with the following essential requirements: the mass of the vibrator on its supporting springs ( excluding solid eccentric and cube hut, including mass of mould, mould clamp and hopper )
- b) Out of balance eccentric shaft moment.
- c) Normal running speed of eccentric shaft.
Speed of shaft 12000 -+400 rpm
The center of gravity of the vibrator, including the cube and mold, will be either in the center of the eccentric shaft or within a distance of 25 mm below it. For this purpose, a mild steel plate vibrator can be fixed.
The bed of the vibrating machine will be made of steel channels and provided with four cast iron legs. It will be provided with four leveling bolts. Four support springs will be fitted to position the coiled springs. A bracket shall be provided to fix one end of a tension spring.
The vibrator will be mounted on four coiled springs. The vibratory platform shall be provided with two guide pieces for positioning a cast iron mold clamp that takes a cube mold of size 70.6 mm. A suitable arrangement shall be provided for mounting the hopper and a tension spring will be fitted. A brass hopper fitted with projected lugs on a solid steel frame will be positioned on the mold.
The vibrator will form a rotating shaft with a precise shaft. A pulley shall be fitted to the shaft.
Springs -The stiffness of the spring shall be such that the natural frequency of the machine mounted on it is well below its minimum running speed.
The drive should be by an endless belt running on a winch on the motor and a winch on the vibrator.
The mold will be 70.6 mm in size and will usually be constructed.
The dimensions of the mold with tolerance will be specified in the table
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