Week 4:- Pin Unit Design Challenge

FUNDAMENTALS OF PIN UNIT DESIGN;

It is necessary to have a two pins to locate the panel,and here one pin must arrest 4 way(that menas 4 translational movement) and other must arrest 2 way(rotational movement of 2 sides) of a car panel

• pin should engage 3 to 5 mm of car part entry surface.

• All pins should be accomdated with 2 way adjustable shims irrespective of directionof arresting.

• Round pins can be used for 2 way arresting of car part only if the hole is slot.

• Diamnond pins should be used in case of 2 waty arresting of car part if the hole is round.

• Diamond pins should be used in case of 4 way arresting of car part if the hole is slot.

The axis of the car panel hole and the axis of the pin should be same

The pin tolerance for a geo pin will be closer tolerance for example -0.15mm and for re spot is 0.28mm

FIXED PIN UNIT DESIGN;

In fixed pin unit the unit will be fixed at one position with respective co ordinates we need ,the unit will mounted in the base plate of the fixture

In this unit we move only 2 directions i.e x and y axis and doesn't move z axis.

There are different parts attached in fixed pin unit

• LOCATING PIN

• PIN RETAINER BLOCK

• L' BLOCK

• BLADE

• RISERS

TYPICAL PARTS OF A PIN UNIT:

Pin:

• Pin a part which locates the car panel. A pin can either be a make part or a standard part also.
• Pin should have grinding surface on shaft with fits on to which the pin retainer will be fitted.
• The mounting surface of the pin should be a fine machined surface.
• The pin should have a step machine surface to lock the rotation, which matches with the pin retainer.
• The mounting surface of the pin retainer to the blocks should be a machined surface.
• All machined planes should be perpendicular to the axis of the pin shaft.
• Pin must have a fastening provision like tapped hole from the bottom or a V grove from the side.
• A pin must be hardened (Heat treatment) and black oxide finished in general.

PIN RETAINER BLOCK;

The block is used to locate the pin wihout any deviations by using fastening.

And we use different types of retainer block for reqiured space and design.

the retainer will be assemble in L block.

L'BLOCK;

• L' block is used to provide the shim to move the pin in 2axis for the adjustment and locate the pin in centre of the car panel hole

BLADE;

• Blade is used to clamp the L block and riser and also use to increase the height of pin unit

RISERS;

• Riser is the base unit of the fixed pin unit to clamp the unit and base plate of the fixture
• mostly riser we prefer the standard l type riser

RETRACTEBLE PIN UNIT;

• The unit is used to locate the panel by using pin
• But the entire pin assembly will be mounter on the pneumatic cylinder
• The unit which contains a cylinder of one r two rod of required purpose ,in cylinder the pin unit will be attached
• In single rod pneumatic cylinder the locating pin will be directly mounted in the rod
• In double rod pneumatic cylinder pin unit will be mounted i.e pin,retainer and mounting plate etc.,

SINGLE ROD CYLINDER;

DOUBLE ROD CYLINDER;

AND THE TOTAL ASSEMBLY VIEW OF FIXED AND RETRACTABLE PIN UNIT;