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Wonderful 4F21-SS
Wonderful 4F21-SS
Wonderful 4F21-SS
Wonderful 4F21-SS
Wonderful Orthopaedic, Trauma & Prosthetics

Wonderful 4F21-SS

Product Code: OTAP-PLAC-3037

Stainless, for the clamping force a heavier build asks for.

A tube clamp does not bolt to the pylon; it grips it. How much grip it can generate depends on how hard its screws can be driven, and that depends on what the clamp is made of. Listed on Medigear.uk for UK business buyers.

Sections
Prosthetic Components & Adaptors
Categories
Orthopaedic, Trauma & Prosthetics
Condition
New
Origin
China
Seller Type
Certified Professional Seller
CE & ISO Certified
Global Shipping
Supplier: Medigear
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Most connections in a prosthesis are positive. A bolt passes through a hole. A thread engages a thread. A pyramid seats in a receiver and is locked by screws bearing on its faces. In each case the parts interlock, and the fixing holds them in that engagement.

A tube clamp is not like that. The pylon is a plain cylinder with nothing to engage, and the clamp holds it purely by friction. A slot through the clamp body allows the bore to close slightly as the screws are drawn up, and the resulting pressure between bore and tube generates the friction that resists the tube rotating or sliding under load. Nothing prevents movement except that grip.

Everything about the joint follows from that. The friction available depends on the clamping pressure, and the clamping pressure depends on how much force the screws can apply. How much force the screws can apply depends on what they and the clamp body are made of, because the limit is where the thread or the body begins to deform rather than where the operator stops turning. Material therefore sets the ceiling on the whole joint.

Stainless steel raises that ceiling relative to a light alloy of the same geometry. A stainless body and stainless threads tolerate higher screw torque without damage, which allows more clamping force, which allows the joint to resist higher loads without slipping. For heavier users or higher activity levels, that is the reason to specify the material rather than corrosion resistance alone, though the corrosion behaviour is a genuine secondary benefit at a fitting sitting low on the limb.

Two figures follow directly and should come from the manufacturer rather than from judgement. The clamp screw torque is the value that delivers the intended clamping force, and it is specific to the material and the screw specification. The minimum tube insertion depth defines how much of the pylon sits inside the bore, which determines the contact area the friction acts over. Under-torque and shallow insertion both reduce grip, and both do so without any visible sign until the joint moves.

Within that, the clamp performs the usual functions: insertion depth sets limb length, rotation before tightening sets toe-out or toe-in, and both remain adjustable as alignment needs change.

Bore diameter is the compatibility question and is not stated in this reference. Modular systems use two pylon diameters and a clamp takes one of them, with no adaptor reconciling the difference.

This is a component supplied for fitting within a prosthesis by a qualified prosthetist, who cuts the pylon, sets length and rotation, and tightens the clamp to the specified torque. The manufacturer, grade, bore, build height, rating, screw specification, torque and insertion depth are provided by the seller at quotation, with UKCA or CE marking documentation, the declaration of conformity, instructions for use and warranty terms issued by the manufacturer or held by the seller.

Heavier users are served by a material that supports higher clamping force at the pylon joint.

Higher activity levels place greater cyclic load on the clamp, which bears on material selection.

Limbs used in wet or dirty conditions benefit from the corrosion behaviour of stainless at a low fitting.

Limb length is established at this fitting through pylon insertion depth.

Toe-out and toe-in are set by rotating the pylon before the screws are tightened.

Alignment revisited during rehabilitation depends on a clamped joint that can be loosened and reset.

Clinics holding stock need clamps in both materials and both bore diameters, since neither is interchangeable after order.

A Higher Ceiling on Clamping Force

Stainless body and threads tolerate higher screw torque than a light alloy of the same geometry, allowing more grip.

Grip Matched to Load

Higher clamping force means the joint resists higher loads before the pylon can rotate or slide.

Corrosion Behaviour as a Second Benefit

The material also suits a fitting sitting low on the limb, where water and floor-level grit reach it.

Friction Across the Full Contact Area

Closing the slot grips the tube over its whole contact length rather than at any single point.

Length Set at the Bench

How far the pylon enters the bore determines the distance between socket and foot.

Rotation Set Before Tightening

Turning the pylon within the clamp sets toe-out or toe-in.

Adjustment That Can Be Revisited

Alignment changes during rehabilitation are accommodated by loosening, resetting and retightening to torque.

Torque Taken From the Instructions

The figure delivers the intended clamping force and is specific to the material and screw specification.

Insertion Depth Established

Minimum pylon engagement determines the contact area the friction acts over, so it is confirmed before fitting.

Bore and Height Specified Explicitly

Because the reference states material only, both remaining variables are set out on the order.

Supply and Documentation Arranged

Medigear.uk can arrange supply, documentation and the provision of consumables.

Stainless Steel Clamp Fitting

Joining a pylon to an adapter in a modular lower limb prosthesis.

Item Reference: 4F21-SS

To be confirmed against the manufacturer's marking, noting that the code states material only.

Manufacturer

Wonderful Rehabilitation, to be confirmed at quotation.

Material

Stainless steel, with the grade to be confirmed.

Bore Diameter

Confirmed at quotation, as it is not stated in the reference.

Build Height

Confirmed at quotation, as it is not stated in the reference.

Clamp Slot and Screws

Slot closing onto the tube, with screw size, count and type confirmed at quotation.

Clamp Screw Torque

Confirmed at quotation from the manufacturer's instructions.

Minimum Tube Insertion Depth

Confirmed at quotation.

Maximum Body Weight

Confirmed at quotation.

Product Weight

Confirmed at quotation.

Proximal Connection

Confirmed at quotation.

Compatible Pylons and Adapters

Confirmed at quotation, matched to the bore diameter.

Corrosion Performance

Permitted exposure confirmed at quotation.

UKCA or CE Marking and Declaration of Conformity

Issued by the manufacturer and requested from the seller at quotation.

Instructions for Use

Provided by the seller at quotation, and required before fitting.

Warranty Terms

Set by the seller at quotation.

The 4F21-SS is a stainless steel clamp fitting joining a pylon to an adapter in a modular lower limb prosthesis. Most connections in a prosthesis are positive ones, where a bolt passes through a hole or a pyramid seats in a receiver and the parts interlock. A tube clamp is not: the pylon is a plain cylinder with nothing to engage, and the clamp holds it purely by friction, generated as a slot in the body allows the bore to close under its screws. Everything about the joint follows from that. Available friction depends on clamping pressure, clamping pressure depends on the force the screws can apply, and that force is limited by where the threads and body begin to deform, which makes material the ceiling on the whole joint. Stainless raises that ceiling relative to a light alloy of the same geometry, which is the reason to specify it for heavier users and higher activity, with corrosion behaviour a genuine secondary benefit at a fitting sitting low on the limb. Screw torque and minimum insertion depth are the two figures that convert that capacity into actual grip, and both come from the manufacturer. Cutting, setting and tightening are the work of the prescribing prosthetist. Grade, bore, build height, rating, torque and insertion depth are provided by the seller at quotation alongside UKCA or CE documentation. Medigear.uk lists the fitting for UK business buyers and can arrange supply, documentation and the provision of consumables. Enquire for a written quotation.

FAQ

Frequently Asked Questions

Everything buyers need to know about sourcing medical equipment through MediGear.

It is a stainless steel clamp fitting joining a pylon to an adapter in a modular lower limb prosthesis. The bore diameter and build height are confirmed at quotation.

By friction. A slot allows the bore to close as the screws are tightened, and the pressure between bore and tube resists the tube rotating or sliding.

Because grip depends on clamping force, and clamping force is limited by how much screw torque the threads and body tolerate before deforming.

It tolerates higher screw torque than a light alloy of the same geometry, which allows more clamping force and so a higher load before the joint slips.

Yes, as a secondary benefit at a fitting sitting low on the limb, though the primary reason to specify the material is clamping capacity.

Because it is what delivers the intended clamping force. Under-torque reduces grip without any visible sign until the joint moves.

It determines the contact area the friction acts over, so a pylon short of the specified depth is gripped over less area than intended.

Confirmed at quotation. The reference states material but not bore, so the diameter must be specified on the order.

Confirmed at quotation, as it is likewise not stated in the reference.

Insertion depth sets length and turning the pylon before tightening sets toe-out or toe-in, both adjustable afterwards.

A qualified prosthetist, who cuts the pylon, sets length and rotation and tightens to the specified torque.