The M3RHT60 hollow shaft torque arm gearbox combines three layout decisions in one code: a spiral-bevel input stage that turns the motor through a right angle, a hollow low-speed bore that slides straight onto the driven shaft, and a torque arm that carries the reaction instead of a foundation. Size 60 sits in the middle of the horizontal band, the frame most often requested for mid-range conveyor and feeder drives.
A Torque Arm Build That Slides onto the Machine Shaft
On drives where the machine shaft runs in its own bearings, mounting a conventional foot unit means pouring a bedplate, aligning a coupling and keeping that alignment true as the structure moves. The torque-arm construction removes that whole interface: the gear unit is pushed onto the shaft, the reaction arm is pinned to the machine frame, and the drive follows the shaft it rides. Shiftable conveyors, relocating stackers and machines that are re-levelled during maintenance are the classic users of this arrangement.
M3RHT60 Type Code, Letter by Letter
| M3 | Industrial gear unit family, three geared stages |
| R | Spiral-bevel right-angle input stage (P would keep the motor in line) |
| H | Hollow low-speed shaft bored for a key (S would end in a solid keyed stub) |
| T | Torque-arm reaction, shaft-mounted build (F would bolt down to a foundation) |
| 60 | Frame size 60 within the horizontal band 50 to 90 |
The code reads like a specification: every letter is a choice the buyer makes once and carries through the whole plant, which keeps spares common between machines that share a shaft class.
Installations that call for exactly this arrangement:
- Belt and chain conveyors where the drive rides the head shaft
- Cooler and dryer drums with independent bearing-mounted shafts
- Screw feeders and live-bottom bins in chemical service
- Bucket elevators in cement, lime and grain handling
- Wastewater scraper and sludge rake mechanisms
- Mobile stacker conveyors that relocate with the working face
Where the Hollow Bore Pays Off
The keyed hollow bore meets the machine shaft through a shrink-disc-free, bolt-free interface, so fitting the unit is a lifting-and-pushing job rather than a machining job. The bevel first stage adds layout freedom - the motor hangs beside the machine, clear of guards and material flow - and because all three stages are helical or spiral-bevel, the unit runs quiet and holds efficiency across the ratio band. WGT checks overhung load, service factor and starting duty against the installation drawing before confirming any selection.
Drawings, Selection and Delivery
The catalogue and the size 60 outline drawing are issued as PDFs covering bore diameter, key section, torque-arm pin position and motor interface, so the fitting can be verified before an order. Send the driven machine, motor power and speed, target output speed and the duty profile; the rated-torque check completes the selection and a written quotation follows. Units are factory-tested, packed in an export wooden crate and covered by a one-year warranty.
Available Frames and Their Typical Duty
| Model | Centre distance | Output | Typical duty |
|---|
| M3PSF50 | size 50 | solid shaft, foot | conveyors, feeders |
| M3PSF60 | size 60 | solid shaft, foot | crushers, mixers |
| M3PSF70 | size 70 | solid shaft, foot | ball mills, shredders |
| M3PSF80 | size 80 | solid shaft, foot | kilns, heavy conveyors |
| M3PSF90 | size 90 | solid shaft, foot | mill and kiln drives |
| M3RSF50 | size 50 | solid shaft, foot, right-angle | inclined conveyors, elevators |
| M3RSF60 | size 60 | solid shaft, foot, right-angle | screw classifiers, feeders |
| M3RHF70 | size 70 | hollow shaft, foot, right-angle | agitators, drum drives |
| M3PHT80 | size 80 | hollow shaft, torque arm, parallel | shaft-mounted conveyors |
| M3RHT90 | size 90 | hollow shaft, torque arm, right-angle | heavy shaft-mounted drives |
Note that PSF and RSF frames of the same size share the mounting footprint; the R build simply inserts a bevel stage, so switching layout rarely forces a foundation change.
Questions and Answers
Do you support commissioning and after-sales service?
Every shipment includes an installation manual and a test record. Our engineers answer commissioning questions by e-mail or video call, and spare seals, bearings and shafts remain traceable to your original order for years afterwards.
What is a service factor and which value should I use?
The service factor multiplies your required torque to cover shock and duty class: around 1.0 for uniform conveyors, 1.25 for moderate shocks and 1.5 or higher for crushers, shredders and reversing drives. Tell us the driven machine and we apply the correct value before quoting.
Can the gear unit hold a load on an inclined conveyor?
For inclined belts a backstop prevents the loaded belt from driving the unit backwards when power is cut. Specify the incline angle when ordering so the backstop and the oil level are matched to the actual mounting position.
Installation Examples
Pet-food extruder feeder
A pet-food plant chose reducers for the feeder screws ahead of its extruders. Steady torque at variable output speed keeps the kibble size consistent, and washdown sealing protects the unit during sanitation shifts.
Ceramic tile press feeder
A ceramic tile producer fitted reducers to press feeders. The dusty environment is handled by sealed housings, and the stable low-speed output stops the tile blanks shifting before pressing.
![gear box application map for industry]()
From quarries to food plants - one right-angle drive concept.
Selection Example: Bucket elevator head shaft drive
Take a 45 kW motor at 1470 rpm turning an elevator head shaft at 28 rpm. The ratio follows directly: 1470 / 28 = 52.5, so a ratio near i=52 is selected. In this case the keyed hollow bore slides onto the head shaft while the torque arm takes the reaction, so no foundation or coupling is built. The ratio is the easy part. The service factor for the shock level is what makes the selection safe, and we check that for you at no charge.
![how to choose a speed reducer model]()
Ratio first, then torque, then frame size: the standard selection route.
Size It, Quote It, Ship It
One minute, one model. The WGT Motor & Gearbox Online Selection System covers motor power, ratio and mounting on one screen - enter your numbers and see the model immediately.
Give us the driven machine, the required output speed and the daily running hours, and we return a confirmed model number with torque margin and a firm price - no obligation, no charge for the selection work. Looking for a gearbox for agricultural machine? Tell us the duty point and we will confirm the model in writing.
