1. MAGNA M a g n a D i g i t e c h I n d i a P r i v a t e L i m i t e d PROBLEM SOLVING Scope : Model the entire Mechanism Assembly parts and to determine the problem in Trip Pawl. Input: All parts drawings. Out put: 3D models with necessary drawings Assembly model with necessary drawing Our findings on the assembly

2. MAGNA M a g n a D i g i t e c h I n d i a P r i v a t e L i m i t e d OPEN POSITIONCLOSED POSITION

3. MAGNA M a g n a D i g i t e c h I n d i a P r i v a t e L i m i t e d OBERVATION 1  When we modeled all the parts to nominal dimension and assembled as per the drawing, the Trip Pawl gear teeth is slightly inside (fouling with) the Trip latch teeth (Here Trip Pawl face is tangent to the adjacent pin).  Since we have enough compression in the spring, Trip Pawl can perfectly match to the Trip Latch. In this condition we will have gap between the Trip Pawl face and adjacent pin.

4. MAGNA M a g n a D i g i t e c h I n d i a P r i v a t e L i m i t e d OBSERVATION 2  Then we have tried with changing the dimensions in Trip Pawl. We have changed it to the maximum allowable tolerance. The changed dimensions are shown in bold (4 dimensions)

5. MAGNA M a g n a D i g i t e c h I n d i a P r i v a t e L i m i t e d OBSERVATION 2 cont.  You can clearly see that the gear teeth of Trip Pawl is matching with most of the teeth of Trip Latch except the first two.  The difference between the first and second is the amount of engagement is only 50% when compared to the first case.

6. MAGNA M a g n a D i g i t e c h I n d i a P r i v a t e L i m i t e d OBSERVATION 3  Only small amount of material is touching with Trip Latch.  There is a chance to slip.

7. MAGNA M a g n a D i g i t e c h I n d i a P r i v a t e L i m i t e d OBSERVATION 4  We have just tried with using maximum tolerance only in Trip Pawl and in Lever the dimension 1.700 is out of spec I.e, measuring 1.720  Now the condition is still worse and now the trip pawl is just touching the latch at two teeth.

8. MAGNA M a g n a D i g i t e c h I n d i a P r i v a t e L i m i t e d CONCLUSION  You can have perfect match when all the parts are maintained in nominal dimension.  When parts like Trip pawl, Latch, Housing & Lever has utilized maximum tolerance then there seams to be chance for slip.  If the Lever is out of spec by +.02 to +.03 in dim 1.700, then also you will have problem.  You can introduce gauge for inspecting Lever assembly with Trip Pawl & Spring Such that it should check the outer radii of Trip Pawl from Lever center.  If the Lever assembly with Trip Pawl is o.k then the problem will be in machining of Housing.  In housing you can introduce direct dimension from the main center to Trip Latch Mounting boss.