Title of Invention

TRAP UPSET OF SHOE HOLD DOWN PINS USED IN DRUM BRAKE ASSEMBLY

Abstract

This invention of Trap upset of Shoe hold down pins denotes the process inside closed two open dies. The function of the Trap upset is to enlarge the portion. Steel in coil form fed into an automatic Cold forging machine to cut preform and final form as per the profile of pre-part. The pre-part is manually fed into another machine with two split dies and a punch. The Punch moves forward while the product is gripped between the two dies and the moving pin trap upsets the profile and return back and stops.When the two split dies automatically move out, the product is taken out as a final part.

Full Text

PRIOR ART This type of show hold down pins had the profile pinched out of the shank diameter, i^ch are weak at ttie junctions, and there was every possibility of breakage. These pins are susceptible for slippage during assembly and also due to vibrations In the machine. NOVELTY OF THE INVENTION Trap bloating of show hold down pin is fully cold forged in two stages. 1. Normal heading of pre part. The details of this is shown In Figure - 2 2. Reheading the required profile by trap bloating in a rod header using split dies which have been previously sparked at their inner faces, the required profile. The details of this Is shown in Figure - 3 - Cold forging of such parts ttnat are safety critical is the only option and with this process the reheaded profile is stronger and will not slip put from the assembly, which has a spring and a special washer. - Dimensional accuracy and repeatability. • Can be mass produced in a short time. Details of process: Process I: Heading of blanks using an ordinary single die double blow header 1. Input to machine: Cold heading quality annealed wire of suitable diameter. 2. Input to die: Wire cut-off 3. Output from the die: Co(3 headed pre part. The above process Is equivalent to any notmal cold heading process done with a single die and two punches to get the headed profile. Process - II Profile formation using Rod Header. 6. Input to the machine: Cold headed part fed manually to the machine. 7. Machine consists of two split dies with profile on each side matched and lapped to suit wire size. 8. Trap pin acts as the front stopper for the input part. 9. The part is placed between the two split dies and the trap pin moves forward during ttie stroke of the machine. 10. As the two split dies are gripped, cold forming taken place and the die cavities are filled thus producing the part. The details of this Is shown in Figure - 4. CLAIMS 1. THE PROCESS OF TRAP UPSET OF SHOE HOLD DOWN PINS USED IN BRAKE ASSEMBLY 2. Normal heading of pre part 3. Reheading the required profile by trap bloating in a rod header using split dies wNch have been previously sparked at their inner faces, the required profile. 4. Cold forging of such parts that are safety critical Is the only option and with this process the reheaded profile is stronger and wil not slip put from the assembly, which has a spring and a special washer. 5. Dimensional accuracy and repeatability.

Documents:

0371-che-2003 abstract duplicate.pdf

0371-che-2003 claims duplicate.pdf

0371-che-2003 description (complete) duplicate.pdf

0371-che-2003 drawings duplicate.pdf

371-che-2003-abstract.pdf

371-che-2003-claims.pdf

371-che-2003-correspondnece-others.pdf

371-che-2003-correspondnece-po.pdf

371-che-2003-description(complete).pdf

371-che-2003-form 1.pdf

371-che-2003-form 26.pdf

371-che-2003-other documents.pdf