Products Power Transmission Products

  • Shock Guard®

TGM Shock Guard®

Has a number of superior features compared with overload protectors, such as conventional shear pin, friction, ball, and roller types.

TGM Shock Guard

Standard

Capacity N·m Repeat working torque precision Backlash Reset Method
0.6 to 1060 ±5% None Automatic

1.Features

  • Impervious to dust, oil, and water infiltration, and oil leakage as well
  • Accuracy of consecutive repeated trip torque fluctuations is within ±5%
  • There is no phase shift between the drive side and driven side due to the engagement of the cam follower and pocket.
  • Long service life withstanding over 100,000 trips
  • When the Shock Guard trips, the limit switch can be actuated as the LS detection plate slides in an axial direction.
  • Accurate trip torque can be set just by turning the adjusting screw at one location with a hexagonal wrench.
  • Ready to use as it is pre-lubricated with the proper amount of quality grease prior to shipment

2.Structure

TGM Structure
  1. (1) Adjusting Screw
  2. (2) Coil Spring A
  3. (3) Spring Seat
  4. (4) Case
  5. (5) Lever
  6. (6) Fulcrum Pin
  7. (7) Bearing B
  8. (8) Roller Pin
  9. (9) Cam Follower
  10. (10) Packing
  11. (11) Seal
  12. (12) Bearing A
  13. (13) Thrust Washer
  14. (14) Cam Shaft
  15. (15) Cover
  16. (16) LS Detecting Plate
  17. (17) Cam Actuation Plate
  18. (18) Coil Spring B
  19. (19) Spring Pin
  20. (20) Hexagon Bolt
  21. (21) Hexagon Set Screw
  22. (22) Hexagon Set Screw

3.Operating Principles

Animation showing the operating principle of the TGM Series

TGM Animation GIF
During normal operation (engagement)
Torque is transmitted through engagement by contact with the cam follower and pocket.
Pressure is added on the cam follower pocket using a rectangular spring to firmly push down in the radial direction. This allows Tsubaki to create a backlash free overload protection device with high trip torque precision.
Reset is automatic, so the cam follower will reset to its original position when restarted. There are two points of contact so there is no misalignment with the original phase.
During overload
During overloads, the cam follower pops out of the pocket and begins to rotate along the outer race of the camshaft. There is no sliding, only rolling, so the nominal overrunning drag torque is extremely low for excellent durability. Further, the simple design with one point of engagement means that its high trip torque precision is not lost.

LS sensor plate operation

LS sensor plate operation Animation GIF
Movement during overloads (trips)
When an overload trips the Shock Guard, the LS sensor plate slides along the shaft.
This activates the limit switch and cuts the power, and it can also be made to trigger an alarm.
The LS sensor plate slides three times for every one trip.

4.Model Numbering Example - TGM Series

TGM 60 - T H 30 J DY - WS - N25
Series Size Shock Guard side Shaft bore tolerance Shaft bore diameter (1mm units) Keyway tolerance Set screw position Spring type Set torque value

Size

  • 3
  • 6
  • 20
  • 60
  • 200
  • 400
  • 800

Shaft bore tolerance

  • F: F7
  • G: G7
  • H: H7
  • J: JS7
  • P: P7
  • M: M7
  • N: N7
  • K: K7
  • R: R7

Keyway tolerance

  • J: New JIS Js9
  • P: New JIS P9
  • F: Old JIS F7
  • E: Old JIS E9

Set screw position (Position from LS Detecting Plate)

  • DY Set screw position fig.

Spring type

  • No: Standard spring
  • WS: Enhanced spring
    (Except TGM6, TGM800)
  • SS: Enhanced spring
    (Except TGM3, TGM400)

Set torque value

  • The torque setting is shown in N·m units.
  • *Shown to one decimal place when the torque setting is less than 10N·m.
  • Code T indicating Shock Guard side is used for no-coupling types as well.

5.Model Numbering Example - TGM Series Coupling Type

TGM 60 C - T H20JDY X C H30E D2 - WS - N18
Series Size Type Shock Guard side Same notation as no-coupling type Coupling side Same notation as no-coupling type Set screw position * Spring type Set torque value

If the shaft bore is a pilot bore, the code for the Shock Guard side will be TR and the code for the coupling side will be CR.

Size

  • 3
  • 6
  • 20
  • 60
  • 200
  • 400
  • 800

Shaft bore tolerance

  • F: F7
  • G: G7
  • H: H7
  • J: JS7
  • P: P7
  • M: M7
  • N: N7
  • K: K7
  • R: R7

Keyway tolerance

  • J: New JIS Js9
  • P: New JIS P9
  • F: Old JIS F7
  • E: Old JIS E9

Set screw position of the coupling side *

  • D0 Set screw position fig.
  • D1 Set screw position fig.
  • D2 (Standard) Set screw position fig.
  • D3 Set screw position fig.
  • D4 Set screw position fig.
  • D5 Set screw position fig.
  • D6 Set screw position fig.
  • D7 Set screw position fig.
  • D8 Set screw position fig.

Spring type

  • No: Standard spring
  • WS: Enhanced spring
    (Except TGM6, TGM800)
  • SS: Enhanced spring
    (Except TGM3, TGM400)

Set torque value

  • The torque setting is shown in N·m units.
  • *Shown to one decimal place when the torque setting is less than 10N·m.
  • Note: The set screw position of the Shock Guard side is as seen from the LS detecting plate side, and the set screw position of the coupling side is as seen from the hub side.

Model numbers for Shock Guards changed on April 2, 2018.