Shaft Facts

SHAFTS FACTS Solid, tubes and key-ways DetAiLed inFOrmAtiOn On ShAFtS FOr OverheAd dOOrS with tOrSiOn SprinGS. Main function: The shaft passes on the torque, given by the torsion springs to the cable drums. This of course with the aim to balance the door which is held by the lifting cables.

So, the shaft enables the drums to be secured in such fashion that they can rotate or be driven simultaneously. The shaft system contains fitting of the springs, drums (with lifting cable), spring plugs, coupler, collars, operator etc. inches One of the first things you notice when you enter the door business in Europe is the fact that the diameter of the shaft is in inches (“). This is because companies that started supplying the door industry in the late seventies imported a lot of parts from the United States. None of the door components suppliers were willing to heavily invest in aluminum die cast tooling to have drums and spring plugs made in metric sizes. This is why FlexiForce and others still supply shafts with diameter 1” and 1 ¼” with a ¼” key way. So a unique, world wide standard!

Types and application range Flexi-Force offers various types of shafts: • Solid shafts - 702C-2000 etc. black, 1”, with key-way - 702-3500Z etc. galvanized, 1”, with key-way - 699-4500Z etc. galvanized, 1¼”, with key-way • Key-way tubular shafts - 702GBL2750 etc. galvanized, 1”, with key-way, 2mm material - 705GB-2750 etc. galvanized, 1”, with key-way, 3mm material • Tubular shafts (tubes) - 701-2750Z etc. galvanized, 1”, 2mm material Each with their specific application range. This range is determined by the technical specification of the shaft and the construction of the shaft assembly and installation. Main features of the shaft are: shape, diameter, solid/tube and yield stress of the material. Important information on installation is

SHAFTS FACTS applied maximum drum diameter, distance to nearest shaft support/bearing plate and total door weight hanging on the cables. With this information you can calculate the maximum torque on the shaft and decide which shaft is strong enough.

Black vs. galvanized Initially only black (natural) solid shafts were used on industrial doors and black tubular shafts were used on residential doors.

Black means, untreated, phosphate steel, which provides a very thin protective film against corrosion. The key way was first milled in the full length of the solid shaft. Later the key way was made directly in production (hard drawn pulling). Galvanized shafts were introduced because the European customer wanted something better than the greasy, rusty bar above the door, so through quality demands.

Key-way On industrial doors only shafts with key-way are used. This makes it possible to create a fixed connection based on shape with the help of a key. Important, because of the high torque in the shaft, which is generated by the torsion springs. The keyway shaft is also needed to make a good connection between two shaft parts. For installation reasons most shafts of wider doors (w>3,5m) are cut in half and need to be connected again.

The same goes for connecting an operator. Most motors and chain hoists have 1” shaft access and ¼” key.

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Solid vs. tube The advantage of solid shafts is their superior torsional rigidity, their relatively high resistance to bending and the application of standard size ¼” keys; they do however represent the most expensive solution. The 1¼” solid shaft is used for large, wide and heavy doors (from approx. w>7 m). Logically, for 1¼” shafts, the drums, spring plugs, spring rupture protectors, bearing plates and clutches must also be 1¼”. FlexiForce offers the complete range for this.

Tube shafts are used on a lot of residential doors. In this case there is no fixed connection based on shape. The connection is achieved by fastening set screws and thus deforming the tubular shaft. This is acceptable for mounting spring winding plugs and cable drums but not for safety components, like ratchet wheels of spring break devices. In those situations you have to create a fixed connection based on shape. Some companies use tubular shafts and deform both ends to have a fixed connection and so prevent using keys or set screws.

702C solid shaft After production the shaft is covered with a thin oil film to protect during transport.

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702C

702GBL/705GB-3000

key-way tube shaft: A FlexiForce invention!

To reduce costs FlexiForce together with a customer and a supplier developed the key-wayed tubular shaft made out of 3 mm galvanized steel, article code 705GBL. This was in 1995.

This shaft is being made on a roll forming machine, where the seam is welded and galvanized online. The distance between two radius determine the depth of the key way, which is different than a standard ¼” key way. Special keys of 3/8x1/4” are needed for this key-way.

• For very heavy overhead doors, solutions without springs are provided, where the shaft has a diameter of 200 mm or larger.

These doors are driven by heavy-duty e-operators.

Cover it up!

The finishing touch: FlexiForce introduced black plastic covers to close both ends of the tube shafts. Looks better and prevents moist and dirt coming out of the shafts on site.

701CAP for the tube shaft, 702CAP for the 2 mm tube shaft with key-way and 705CAP for the 705GBL-shaft.

Depending on the installation type, this shaft can be used for all lift systems up to doors of 5000x4200mm (wxh) or max. door weight of 300 kg. This is covering almost 75% of the industrial doors. A residential version (702GBL..) made of 2 mm steel was added to the program. This shaft is ideal for garage doors up to a max weight of 160kg

701CAP

Solid shaft production

701CAP

FlexiForce solid shafts are manufactured using a highly specialized process. Cylindrical lengths of steel of 26 mm are drawn through different dies until the appropriate exterior diameter and keyway sizes have been realized. This manufacturing method results in extremely accurate dimensioning.

It prevents the so-called “corkscrew effect” and it leaves no sharp edges. This method is better than milling in the key-way afterwards.

“Need-to-knows” on shafts • To be able to mount standard motors with 1” shaft access, to the different kind of shafts on the market you need shaft adaptors. Since FlexiForce is supplying industrial motor since beginning of 2008 we have different solutions in our program.

Our coupler 702ST-1/2 is a solution to connect 1” shaft with 1¼” shafts.

• Some bigger independent door companies have introduced their own size of shaft in the past. Main reason is of course to protect the after sales maintenance on their doors. But also an optimum of strength and used material is the reason for this shaft design. For example: diameter 25, 30 mm and even 32 mm hexagon shaped shafts where no key is needed.

• With narrow but high overhead doors there is often too little room to fit the springs; this problem can be solved by running the shaft outside the days opening or by placing an additional shaft above the shaft (tandem shaft) and connecting the two via chain and gear wheels. Also when in theory cable of more than 6 mm is needed, a tandem shaft could be the solution.

• Did you know that 1” shafts in fact have an external dimension that is a fraction under 25.4 mm?

702CAP

705CAP