FREQUENT QUESTIONS, HELPFUL ANSWERS
Have a question concerning your Thern product? Chances are it has been asked before. Below are helpful answers to many of our most frequently asked questions. If the answer you are looking for is not provided below, please contact us!
Does Thern offer a rooftop davit crane and/or a rooftop crane hoist?
Thern has several davit crane models that are appropriate for rooftop applications. Whether you are looking for a rooftop davit crane or a rooftop crane hoist, Thern can offer you long-lift solutions for servicing HVAC equipment or other applications.
What 20,000 lb winches and 40,000 lb winches does Thern offer?
Does Thern offer a stainless-steel hand winch with a brake?
Thern offers more than one type of a stainless-steel hand winch with a brake. The M4042PBSS model with a capacity of 1,000 pounds and the M4312PBSS model with a capacity of 2,000 pounds. Both have a frame and drum that are constructed with stainless steel and come standard with an automatic Weston-style brake.
Are there any Thern air winches or air-powered winches for sale?
Thern offers a variety of air winches or air-powered winches with capacities up to 37,000 pounds. These air winches can be referred to as pneumatic winches or air tuggers. Check out our Big Red, Mini TA Series, 4771 Series, as well as our C Series. If you’re unable to find what you are looking for, we can design a custom air-powered winch specialized to fit your application.
What lifting equipment parts does Thern sell?
Thern offers a variety of lifting equipment parts such as wire ropes, hooks, sheaves, headache balls, vertical lead blocks, and other lifting equipment.
Does Thern offer material handling lifting equipment or similar products such as a conveyor belt pulling winch or a railcar moving winch?
Thern offers multiple solutions from material handling lifting equipment to a conveyor belt pulling winch. We even provide a railcar moving winch. We can design a solution specific to your application. The engineering team at Thern can customize virtually any winch in our lineup to accommodate specific speed and control requirements. We can also accommodate site-specific variables such as grade, curvature, and distance. See our online portfolio for some of the most challenging and unique applications we’ve solved for our customers.
Does Thern manufacture any explosion-proof hoists?
Thern offers a variety of lifting solutions that meet ATEX requirements for explosive atmospheres. Just tell us the hazard class/environment the hoist, winch, and controls will be exposed to, and we can design an explosion-proof hoist or system to accommodate it.
Are wall-mounted electric winches available at Thern?
Thern offers much more than just wall-mounted electric winches. Many of Thern’s portable and fixed-mount winches are suitable for mounting in different orientations, including floor, wall, and ceiling.
What compact hand winches and/or vertical-lift hand winches does Thern sell?
Thern manufactures a variety of compact hand winches and vertical-lift hand winches suitable for both vertical lifting and horizontal pulling applications. These include both spur gear and worm gear models that accommodate a variety of distance and load requirements. Thern also offers a hand winch that can be drill driven.
Does Thern offer a small vehicle-mounted crane or a crane attachment for a truck?
Several of Thern’s standard crane models can be used as a small vehicle-mounted crane. Additionally, Thern’s Workmate, a hitch-mount davit crane base, was specially designed to be compatible with a standard 2” receiver hitch. The Workmate allows customers to have a crane attachment for a truck, and it can be situated on the ground behind or to the side of the associated vehicle.
What is a mine winch?
Thern provides winches for a variety of mining applications. Mine winches can take on several tasks from MRO to cart pulling to conveyor take-up and tensioning. Some of our customers utilize our products for drag lines and dredging, while others will use them for shaft sinking and plumb bobs.
What’s the difference between an electric hoist and an electric winch?
The difference between an electric hoist and an electric winch is that a hoist refers to a pulling device that lifts vertically with a wire rope or chain. Many people think of a winch as a device that pulls horizontally, when in fact, Thern winches can be placed in virtually any orientation (floor mounted, wall mounted, or underhung) and can pull both horizontally and vertically when properly equipped. Electric hoists will require an automatic brake for vertical lifting applications, while winches for horizontal pulls would not necessarily require a brake. Please reach out to our sales staff to discuss your project and the best solution to fit your needs.
What are the advantages of a motorized davit crane vs. a motorized jib crane?
If the weight, height, and reach requirements fit within a Thern davit crane capacity, a davit crane will be easier to install, operate, maintain, and is generally more affordable. Additionally, many of Thern’s davit cranes are more portable than a motorized jib crane. If you buy numerous bases, you can move the cranes to different locations to solve multiple lifting applications with just one crane.
What are the advantages of a davit crane vs. a gantry crane?
A gantry crane and davit crane often serve very different functions, but there are times that a davit can serve the same function when equipped with a rolling base.
What’s the difference between a stainless-steel davit crane vs. an aluminum davit crane?
An aluminum davit crane, while lightweight and corrosion resistant in some environments, sacrifices a significant amount of lifting capacity due to the physical properties of aluminum. A stainless-steel davit crane, while somewhat heavier, provides the ultimate solution in corrosion resistance and lifting capacity.
How do you calculate the fleet angle of wire rope?
Fleet angle is the angle between the wire rope and an imaginary line extending perpendicular to the drum. The fleet angle varies with the distance between the lead sheave and the drum. Using the correct fleet angle of wire rope will ensure your winch is operating at its full capacity and not causing undue wear.
What are air winch safety best practices?
In addition to all winch safety, which includes air winch safety, best practices are to:
- Read the owner’s manual
- Make sure the winch is securely mounted
- Make sure supply lines are in good shape and are secure
- Make sure the FRL is installed and in good shape
- Install mufflers to reduce sound level. Mufflers with a filter element can be installed to reduce oil misting for the motor lubrication.
- Install a shutoff valve
- Use controls with an estop if the shut off valve is not within reach of the operator
- Install a drum guard
What’s the difference between electric lifting equipment vs. manual lifting equipment?
With manual lifting equipment (such as a hand winch) the work is being done by the operator that is turning the handle of the winch. With electric lifting equipment, the electric motor does the work to turn the drum and spool the lifting rope. Thern offers a variety of both electric and manual lifting equipment.
What’s the difference between an air tugger winch and an electric tugger winch?
An air tugger winch is powered pneumatically and designed for maritime use. An electric tugger winch is powered by electricity. If the load is higher or needs to move at faster speeds, then an electric winch may be better suited for the job.
What’s the difference between a portable davit crane and a stationary davit crane?
A portable davit crane is designed so that it can be easily disassembled and moved to a different location and reassembled for lifting operations. Generally, stationary davit cranes offer the benefit of longer reach over a portable davit crane of comparable capacity. Thern offers a variety of both portable and stationary davit cranes with different lifting capacities.
What’s the difference between an electric davit hoist and a hydraulic hoist?
An electric davit hoist requires an electrical input and uses an electric motor to turn the drum spooling the wire rope. A hydraulic hoist requires pressurized hydraulic fluid (typically from a hydraulic power unit) as input for a hydraulic motor, which turns the winch drum to spool the wire rope.
Where can I obtain parts for my Thern winch or davit crane?
Service parts can be obtained directly from the Thern factory by contacting Thern Customer Service at 800-843-7648.
Where can I obtain repair service for my Thern winch or davit crane?
Please contact the Thern Customer Service Department at 800-843-7648 with all repair and service inquiries. Our Customer Service Representatives will determine the best course of action to be taken to repair your winch or crane.
What is the warranty policy on my Thern winch or davit crane?
All Thern products carry a two-year limited warranty. Thern, Inc. warrants its products against defects in material or workmanship for two years from the original date of purchase.
What is the importance of underwinding compared to overwinding the wire rope on my winch?
The importance of underwound compared to overwound wire rope depends on the winch being used, and it is most important when a brake is incorporated into the winch. Hand winches with disc brakes only hold the load in one direction. The same holds true for the internal brakes used on 477 and 4WP2 series power winches as well as the band brake on TA Series air winches. This means that running any of these winches with the wire rope wound incorrectly will cause the winch to work against the brake. This could cause the brake to function improperly which could allow the load to fall. It will also cause premature wear on the brakes. Prolonged use of overwound wire rope on Series 477 power winches will also cause internal failure to the reducer (gearbox), and the frame of a hand winches will flex far less with underwound wire rope.
How does the friction disc brake on my Thern hand winch operate?
Click here for a complete explanation.
Can I convert a ratchet/pawl style Thern spur gear hand winch to include a disc brake assembly?
Due to the substantial amount of difference between the components used in these two styles of spur gear hand winches, it is not cost effective to do this type of conversion.
What is the importance of underwinding compared to over winding the wire rope on my hand winch?
What is the importance of underwinding compared to over winding the wire rope on my portable power winch?
What type of lubricant is used in the reducer (gearbox) of my Thern Series 4WP2 power winch? And what is the capacity?
The reducer on the 4WP2 Series holds 44 oz. of Mobilgear 630 or Mobilgear 600 XP 220 gear oil.
What type of lubricant is used in the reducer (gearbox) of my Thern Series 477 power winch? And what is the capacity?
The reducer on the 477 Series holds 92 oz. of Mobilgear 630 or Mobilgear 600 XP 220 gear oil.
What type of lubricant is used in the reducer (gearbox) on my Thern 4WS1M, 3M, or 6M Series power winch? What is the capacity?
What type of lubricant is used in the reducer (gearbox) on my Thern 4WS9M, 16M, or 26M Series power winch? What is the capacity?
What type of lubricant is used in the reducer (gearbox) on my Thern 4HS, 4HWF, or 4HPF Series power winch? What is the capacity?
Can I convert my Thern TA Series air winch from manual band brake operation to automatic band brake operation?
Please consult with Thern, Inc. for approval before attempting this conversion. Any conversion attempted without Thern’s approval will alter the finished product from its original design and could void the warranty.
How do I drain and refill the oil in the reducer (gearbox) on my Thern TA Series air winch?
How do I drain and refill the oil in the air motor on my Thern TA Series air winch?
What type of lubricant is used in the reducer (gearbox) on my Thern TA Series air winch? What is the capacity?
Click here to view the reducer lubrication table.
What type of lubricant is used in the air motor on my Thern TA Series air winch? What is the capacity?
Click here to view the motor lubrication table.
What is causing my Thern Series 477 power winch to make a grinding noise? The noise seems to be coming from the reducer (gearbox).
Nearly all failures reported with this symptom have failed due to the wire rope being overwound rather than underwound. Overwinding the wire rope forces the worm shaft in the reducer up into the bottom of the motor adapter plate, and over time the large helical gear on top of the worm gear wears into the adapter plate. This misalignment will cause premature failure of the upper bearing and other related components.