Servo tapping unit with built in shock protection
A servo motor in die tapping unit provides built in shock protection for the motor by fixing a shock plate to the servo motor and floatingly mounting the shock plate to a base structure attachable to a stripper plate in a press. Sets of opposing springs allow movement of the shock plate relative the base plate to relieve shock loads when the press is operated, the shock plate guided on dowel pins fixed to the base structure. The shock plate, and tapping unit and base structure form a self contained assembly for mounting together in the press.
1. A tapping unit with built in shock protection adapted to be mounted on a stripper plate in a forming press, comprising:
a servo motor;
a shock plate disposed between said servo motor and a base structure;
said base structure adapted to be fixed to said stripper plate;
a resilient floating mounting connecting said shock plate to said base structure allowing limited movement towards or away from said base structure, said resilient float mounting attenuating shock loading of said servo motor to a predetermined maximum acceleration;
wherein said resilient floating mounting comprises opposing resiliently deflective elements.
2. The assembly according to claim 1 wherein said floating mounting comprises two sets of springs acting on said shock plate, a first set of springs urging said shock plate towards said base structure, and a second opposing set of springs urging said shock plate away from said base structure, the effect of said two sets of springs normally balanced to position said shock plate and attached servo motor positioned apart from said base structure.
3. The assembly according to claim 2 further including guide elements attached to said base structure and slidably received in openings in said shock plate to guide movement of said shock plate caused by shock loading thereof when said press is operated.
4. The assembly according to claim 3 wherein said guide elements comprise a set of dowel pins fixed to said base structure and extending into openings in said shock plate.
5. The assembly according to claim 2 wherein each of said springs in said first set are compressed against a rim of a bore in said shock plate by a headed threaded fastener threaded into said base structure.
6. The assembly according to claim 5 wherein each of said springs in said second set are received in downwardly facing bores in said shock plate and engaged with an upper surface of said base structure.
7. The assembly according to claim 1 wherein said servo motor extends horizontally on said stripper plate and said shock plate extends alongside said servo motor.
8. The assembly according to claim 1 wherein said servo motor extends vertically from said shock plate and said shock plate is affixed to a lower end of said servo motor.
9. A method of protecting a servo motor from excessive shock loading when installed on a stripper plate in a press to drive a tool for forming a thread in a hole in a workpiece in said press, said workpiece engaged by said stripper plate during press operation, the method comprising:
attaching a shock plate between said servo motor and a base structure;
attaching said base structure to said stripper plate; and
floatingly mounting said shock plate spaced above said base structure by opposing resiliently deflectable elements to allow relative movement therebetween so that said shock plate, base structure, and servo motor form a single assembly.
10. The method according to claim 9 wherein said shock plate is floatingly mounted above said base structure by opposing sets of springs allowing said relative movement with respect to said base structure.
11. The method according to claim 10 wherein said sets of springs are arranged so that one of said sets of springs acts to urge said shock plate toward said base structure and said other of said set of springs urges said shock plate away from said base structure.
12. The method according to claim 10 further including guiding said shock plate on a set of guide elements affixed to said base structure and slidable in said shock plate.
13. A tapping unit with built in shock protection adapted to be mounted on a stripper plate in a forming press, comprising:
a servo motor;
a shock plate attached to said servo motor;
a base structure adapted to be fixed to said stripper plate;
a resilient floating mounting of said shock plate spaced above said base structure allowing limited movement towards or away from said base structure, said resilient float mounting attenuating shock loading of said servo motor to a predetermined maximum acceleration;
wherein said floating mounting comprises two sets of springs acting on said shock plate, a first set of springs urging said shock plate towards said base structure, and a second opposing set of springs urging said shock plate away from said base structure, the effect of said two sets of springs normally balanced to position said shock plate and attached servo motor positioned apart from said base structure.
14. A method of protecting a servo motor from excessive shock loading when installed on a stripper plate in a press to drive a tool for forming a thread in a hole in a workpiece in said press, said workpiece engaged by said stripper plate during press operation, the method comprising:
attaching a shock plate to said servo motor;
attaching a base structure to said stripper plate;
floatingly mounting said shock plate spaced above said base structure by opposing resiliently deflectable elements to allow relative movement therebetween so that said shock plate, base structure and servo motor form a single assembly; and
wherein said shock plate is floatingly mounted above said base structure by opposing sets of springs allowing said relative movement with respect to said base structure.