Week 4:- Pin Unit Design Challenge
Aim :- Design of 2 Fixed Pin Units with different risers, blade, etc. and Design of 2 Retractable Pin Units with different risers, blade, etc.
Introduction :- there is mainy two tupes of pin units one is fix type pin unit and another one is retractable type pin unit in detail mentioned below.
Fix pin unit - An assembly of standard and manufacturing parts consisting location pin is called Pin unit. A pin unit in which pin’s position is fix, is called Fixed Pin Unit. Pin unit is used to lock the rotational position of panel. Round Pin is used to control panel in two directions while Diamond Pin is used to control panel in one direction.
Retractable Pin Unit - Inline Retractable Pin unit consist one Pin cylinder which operates the pin in one direction. In this unit Pin is directly mounted on the cylinder and it is must to have pin and cylinder inline with the hole or slot of the panel. Pin cylinder is controlled in two directions with the help of shimming. Below picture is an example of inline retractable pin cylinder.
PURPOSE OF PIN UNIT:
- As by the 3-2-1 locating principle, the introduction of two pins helps to arrest the 6 degrees of freedom (4 axial & 2 radial movements) whereas the other 6 degrees of freedom are arrested by introducing a minimum of three supports.
- Typically, the locating pins are used to locate a body part in a position sufficiently accurate to execute a welding process.
- The body part is constrained by a set of appropriately locating pin so total constraint by locating pin should be fully constrained at all times to prevent any movement.
Pins - Pins are used to locking the rotational movement of the panel. Generally there two types of Pins, one is Round Pin and another one is a Diamond pin. We use two and three-directional shimming for pins as per the angle of the pin w.r.t. the carline. In some cases, we use a collared pin, when the pin is supposed to support the panel as well. For this kind of pin, we provide 3 way shimming irrespective of pin angle to the carline.
MATERIALS USED:C45, EN31, SAE 8620 Steel,
Formula & Calculation for hex bolt usage:
Formula to calculate the length of the screw,
Length of the screw = [1.5 X (std. hole size)] + {distance between the surface of the part to the first surface of the other part}
Pin Block - Also called Pin Retainer. This block holds the pin and restricts the rotational motion of the pin. Pin Block can be either manufactured one or Standard
MATERIALS USED:Steel / ASTM A-36, SS type 303 or 304
Shims - In general, a shim is a thin and often tapered or wedged piece of material, used to fill small gaps orspaces between objects. Shims are typically used in order to support, adjust for better fit, or provide a level surface. Shims may also be used as spacers to fill gaps between parts subject to wear. Shims are the small parts which comes with the thickness of 0.1mm, 0.2mm, 0.5mm, 1.0mm etc.
MATERIALS USED:S.A.E. 1010 CRS FULL HARD, COLD ROLLED STRIP STEEL S.A.E. 1010 FULL HARD, S.A.E. 1020 HRS
Riser - The part which is mounted on the base plate and holds a clamp or pin cylinder on it, is called Riser. Riser can be Standard Part or manufactured part, it varies from project to project. A riser can be a Single part or welded part. Standard risers also have various shapes and sizes.
MATERIALS USED: STEEL ASTM A-36
Designing-
In last fixture the Retractable unit in slightly igher, thus the copy of base plate is taken and then assembled with respect to it.
CONCLUSION:
Hence, As per the objective, the 2 different types of fixed pin units with different Pins, Pin retainer, Blades & risers & 2 different types of retractable pin units with different Pins, Pin retainer, Blades, risers & cylinders are designed and rendered using CATIA V5 successfully.