cadex defence

Ball Arm

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The Ball Arm is the piece that contains the accelerometer and allows the headform to rotate.

ball arm title

The Ball Arm is the piece that contains the accelerometer that calculates the speed of the impact. It is locked in place between the Clamp and the headform.


ball arm

The Ball Arm has been custom designed for our helmet testing machines. If you desire a custom design to use with another machine, please provide the following information with your order.
ball arm
  • The angularity of the arm refers to the drawing measurement C. The different angles most commonly used are 20°, 25°, 30°and 35°.
  • The length of the arm refers to the drawing measurement A.
  • The diameter of the arm refers to the drawing measurement B.
  • Material requested (see below).

ball arm
The ball arm can be made of three different types of materials to reach different weights, depending upon the configuration of your drop assembly.

  1. Magnesium: approx. 425 grams
  2. Aluminum: approx. 620 grams
  3. Stainless Steel: approx. 1575 grams

ball arm

ball arm
Description A E J M O Spherical-Impactor
HeadForm size 1820 2415 3100 3130 3200 3100
Clamp 758 1173 488 458 388 488
4 bolts 82 82 82 82 82 82
Accelerometer kit 10 10 10 10 10 10
Drop Follower / Flying arm 730 730 730 730 730 730
Aluminum Ball Arm 0 590 590 590 590 590
Stainless steel Ball Arm 1600 0 0 0 0 0
Magnesium Ball Arm 0 0 0 0 0 0
 
Total 5000 5000 5000 5000 5000 5000
Standard Request(total drop mass) 5.0±0.1 5.0±0.1 5.0±0.1 5.0±0.1 5.0±0.1 5.0±0.1


  • 4 bolts: Are used to secure the Clamp to the headform.
    Only 5/16 NC 18 - 1 3/4 inch length bolts should be used to avoid any damage to the tread in the head form.
  • Accelerometer kit: Consists of the accelerometer sensor, support bed and cable.
  • Drop Carriage / Flying arm: The drop guiding system on the machine that will maintain the headform and other parts of the drop assembly in the trajectory of the impact.
  • Ball Arm: The Ball Arm contains the accelerometer sensor and is the moving joint connected to the headform. It allows for various positioning of the headform.
ball arm