The RP-P Disc Brake Jaw Flexible Coupling integrates a flat annular brake disc into the coupling hub for use with caliper-type disc brake systems. Retaining all RP jaw coupling characteristics, it covers torques up to 6,650 N·m and bore sizes to Φ145 mm, with multiple brake disc sizes per model.
The RP-P coupling brings the performance benefits of the RP jaw flexible coupling family to drive systems equipped with disc-brake calipers. While the RP-Z integrates a cylindrical drum for shoe-type brakes, the RP-P integrates a flat annular disc — the geometry required by hydraulic and electromechanical caliper brake units widely used in modern crane drives, machine tools, industrial presses, and automated material-handling systems.
Caliper disc brakes offer several advantages over drum-shoe systems in industrial applications: faster response times, more consistent braking torque over the life of the friction pads, easier pad inspection and replacement, and compatibility with high-cycle automated braking sequences. By integrating the disc directly into the coupling hub, the RP-P eliminates the separate disc-hub adapter that would otherwise be required, reducing axial length, controlling disc runout to tight tolerances, and simplifying the drive-train bill of materials.
As with the RP-Z, the RP-P retains the full elastomeric-spider design of the standard RP jaw coupling. The spider absorbs the dynamic torque spike that occurs at the instant of brake application — a particularly significant benefit in automated systems where braking cycles are frequent and the accumulated impact loads would otherwise cause premature fatigue in gears, keys, and shaft shoulders. The marking convention follows that of the RP-Z, with disc dimensions D⊂0;×T and bore diameters specified in the order reference.
| Model | Torque (N·m) | Speed (rpm) | D (mm) | D1 (mm) | D2 (mm) | d1max (mm) | d2max (mm) | E (mm) | L0 (mm) | N (mm) | Brake disc D0×T options |
|---|---|---|---|---|---|---|---|---|---|---|---|
| RP38P | 190 | 9500 | 80 | 66 | 78 | 48 | 34 | 24 | 114 | 37.5 | 200×15 / 250×15 |
| RP42P | 265 | 8000 | 95 | 75 | 94 | 55 | 42 | 26 | 126 | 40.5 | 250×15 / 315×20 |
| RP48P | 310 | 7100 | 105 | 85 | 104 | 60 | 48 | 28 | 140 | 45.5 | 250×15 / 315×20 / 400×20 |
| RP55P | 410 | 6300 | 120 | 98 | 118 | 70 | 55 | 30 | 160 | 52.5 | 315×20 / 400×20 / 500×20 |
| RP65P | 625 | 5600 | 135 | 115 | 134 | 75 | 65 | 35 | 185 | 61.5 | 315×20 / 400×20 / 500×20 / 630×20 |
| RP75P | 1280 | 4750 | 160 | 135 | 158 | 90 | 75 | 40 | 210 | 69.5 | 400×20 / 500×20 / 630×20 / 710×25 |
| RP90P | 2400 | 3750 | 200 | 160 | 180 | 100 | 100 | 45 | 245 | 89.5 | 400×20 / 500×20 / 630×20 / 710×25 / 800×30 |
| RP100P | 3300 | 3350 | 225 | 180 | 200 | 110 | 100 | 50 | 270 | 98.5 | 500×20 / 630×20 / 710×25 / 800×30 |
| RP110P | 4800 | 3000 | 255 | 200 | 230 | 125 | 110 | 55 | 295 | 96.5 | 500×20 / 630×20 / 710×25 / 800×30 / 900×30 |
| RP125P | 6650 | 2650 | 290 | 230 | 265 | 145 | 130 | 60 | 340 | 112.5 | 630×20 / 710×25 / 800×30 / 900×30 |
| Feature | RP-P (disc brake) | RP-Z (drum brake) |
|---|---|---|
| Brake actuator type | Hydraulic or electromechanical caliper | Shoe-type drum brake unit |
| Disc geometry | Flat annular plate (D0 × T) | Cylinder (D0 × T) |
| Pad / shoe inspection | Easy visual check without disassembly | Requires removing shoe spring |
| Typical application | Machine tools, presses, modern crane drives | Overhead cranes, hoists, winches |
| High-cycle braking suitability | Excellent | Good |
For drum brake applications, see the RP-Z brake disc coupling. The complete selection is in the coupling catalogue.
🇫🇷 France — Machine Tool Builder
A horizontal machining centre manufacturer near Lyon integrated RP-P couplings into their pallet shuttle drives. The caliper disc brake provides the holding torque for pallet positioning; the elastomeric spider absorbs the engagement shock that had been causing intermittent encoder faults in the previous rigid-coupling design.
★★★★★
"Encoder fault rate dropped to zero after fitting the RP-P. The spider absorbs exactly the shock spike we could see on our oscilloscope." — Controls Engineer
🇮🇹 Italy — Industrial Press OEM
A mechanical press manufacturer in Brescia selected RP-P couplings for the main clutch-brake drive on a servo-mechanical press range. The flat disc format matched the caliper units already specified, and the precise runout control from the integrated hub-disc design contributed to consistent braking distance across the production batch.
★★★★★
"Braking distance variance between units is now within 2 mm across the full production batch." — Quality Control Lead
🇩🇰 Denmark — Automated Palletiser
A robotic palletiser manufacturer in Odense fitted RP-P couplings on rotating table drives operating at 180 cycles per hour. After 12 months of production operation at this cycle rate, neither the elastomeric spiders nor the caliper pad sets had required replacement — both well beyond the maintenance intervals achieved with the previous coupling and separate disc arrangement.
★★★★☆
"The combined coupling-and-disc unit also saved 38 mm of axial length compared with our previous design." — Mechanical Designer
The RP-P integrates a flat annular plate — the disc geometry gripped from both faces by a hydraulic or electromechanical caliper. The RP-Z integrates a cylinder — the drum geometry contacted on its outer circumference by curved brake shoes. The choice between P and Z is determined by the brake actuator type already specified in the drive system, not by any coupling performance criterion.
Yes — this is one of the key design advantages of the RP-P. The coupling is sized for the drive torque, and the disc is sized independently for the required braking torque and thermal energy per stop. For example, an RP75P coupling transmitting 800 N·m of drive torque can be fitted with any of the four disc size options from 400×20 up to 710×25 depending on the braking torque target, without changing the coupling hubs or bore dimensions.
Use the format: RP[size]P-[D0]×[T] coupling [d1/d2], where D0 is the disc outer diameter in mm, T is the disc thickness in mm, and d1/d2 are the drive-side and driven-side bore diameters in mm. Example: RP65P-500×20 coupling 50/55. Also include keyway widths and depths for both bores, and any sleeve-type requirements. A drawing showing the caliper mounting geometry is helpful to confirm the disc dimensions are compatible with your caliper unit.
Yes. Caliper disc brakes are inherently well suited to high-cycle applications — the flat disc dissipates heat efficiently on both faces, pad wear is uniform and predictable, and pad replacement is straightforward. The RP-P's elastomeric spider provides additional benefit in high-cycle duty by absorbing the impulsive torque at each brake engagement, significantly reducing the fatigue loading on gear teeth, keys, shaft shoulders, and encoder couplings in the downstream drive train.
In the standard RP-P catalogue, the largest available disc is 900 mm × 30 mm, offered on the RP110P and RP125P models. For disc diameters above 900 mm, or for non-standard disc thicknesses and mounting geometries, please contact us with your caliper drawing and braking torque requirement for a custom engineering assessment.
RP supplies the RP-P to machine tool OEMs, crane and hoist builders, industrial press manufacturers, and automation system integrators. Custom disc dimensions, bore configurations, and volume pricing are available. Our technical team is available to review caliper drawings and confirm disc-to-caliper dimensional compatibility. Browse the complete jaw coupling series or the full coupling portfolio.
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