Sunday, November 13, 2016
compound indenxing
compound indenxing
Compound indexing is a combination of two plain
or one complete turn plus 9 holes on the 18-hole
indexing procedures. You will index one number of
circle.
divisions by using the standard plain indexing
method, and another by turning the index plate
When indexing angles are given in minutes, and
(leaving the crankpin engaged in the hole as set in the
approximate divisions are acceptable, you can
determine the movement of the index crank and the
first indexing operation) by a required amount. The
difference between the amount indexed in the first
proper index plate by the following calculations. To
and second operations results in the spindle turning
determine the number of minutes represented by one
the required amount for the number of divisions.
turn of the index crank, multiply the number of
Compound indexing is seldom used because (1)
degrees covered in one turn of the index crank by 60:
differential indexing is easier, (2) high-number index
9° × 60´ = 540
plates are usually available to provide any range of
divisions normally required, and (3) the computation
and actual operation are quite complicated, making it
Therefore, one turn of the index crank will rotate the
easy for errors to be introduced.
index head spindle 540 minutes.
We will briefly describe compound indexing in
The number of minutes (540) divided by the
the following example. To index 99 divisions proceed
number of minutes in the division desired gives you
as follows:
the total number of holes there should be in the index
plate used. (Moving the index crank one hole will
1. Multiply the required number of divisions by
rotate the index head spindle through the desired
the difference between the number of holes in two
number of minutes of angle.) This method of
circles selected at random. Divide this product by 40
indexing can be used only for approximate angles
(ratio of spindle to crank) times the product of the two
since ordinarily the quotient will come out in mixed
index hole circles. Assume you have selected the 27-
numbers or in numbers for which there are no index
and 33-hole circles.double wishbone
In automobiles, a double wishbone (or upper and lower A-arm) suspension is an independent suspension design using two (occasionally parallel) wishbone-shaped arms to locate the wheel. Each wishbone or arm has two mounting points to the chassis and one joint at the knuckle. The shock absorber and coil spring
mount to the wishbones to control vertical movement. Double wishbone
designs allow the engineer to carefully control the motion of the wheel
throughout suspension travel, controlling such parameters as camber angle, caster angle, toe pattern, roll center height, scrub radius, scuff and more.
Saturday, November 12, 2016
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