Belden Inc., a manufacturer of universal joints, has developed a miniaturized universal joint for a surgical tool developed by Tuebingen Scientific Medical GmbH for minimally invasive surgical applications. The surgical manual manipulator system required a joint to transmit the power from the handle to the connecting shaft.

Belden’s universal joint transmits the power from the handle, which acts as a natural extension that emulates the movement of the hand, to the connecting shaft.

Tuebingen Scientific Medical GmbH, a spin-off company of the University of Tuebingen, Germany, is a medical device company specializing in instrumentation for minimally invasive surgery. The surgical systems fill in the gap between conventional surgical instruments and surgical robotics. While conventional instrumentation does not meet the requirements of advanced endoscopic surgeons, robotic systems are too complex and costly for daily routine use.

Tuebingen’s manual manipulator system, called the Radius Surgical System, represents a new class of surgical devices entirely focused on providing full freedom to operate and optimal ergonomics, without the complexity of electromechanical robotic devices. The surgical system has been designed to improve endoscopic suturing and other surgical maneuvers and can be used for a wide variety of surgical procedures in different clinical specialties.

The surgical system comprises two hand-guided surgical manipulators. Depending on the surgical task, graspers, scissors, needle holders and other devices can be attached to the tip and changeover only takes a few seconds. The system required a universal joint to transmit the power from the handle, which acts as a natural extension that emulates the movement of the hand, to the connecting shaft. The joint itself has an outside diameter of 8 mm to accommodate the space limitations of the surgical tool. A deflectable and rotatable tip provides all degrees of handling freedom.

During design development, the customer requested a specialized hub configuration to ensure a secure connection and precise operation. By means of innovative manufacturing processes, Belden made modifications to the standard universal joint concept and delivered prototypes for testing. The final design now incorporates the universal joint and a component of the internal extension as a single piece, which was originally done as two separate pieces. To adhere to the sterilization regulations required by the medical industry, the universal joint was manufactured in stainless steel.

With an outer diameter of only 8 mm (0.315"), Belden’s miniature universal joints are suited not only for medical equipment but for also many other applications in which space is restricted, including miniature machinery and model making. Originally developed in stainless steel for the manual operating device, Belden’s miniature joints are available in alloy steel, with or without plating, and in various stainless steel grades to fit any application.

Belden’s manufacturing processes allow the flexibility to produce small batches economically and made-to-order custom parts just as cost-effectively as high volume standard universal joints. Applications include steering and shift linkage assemblies for race cars as well as industrial and off-road vehicles, aerospace, packaging and conveying equipment, food processing equipment, steel roll forming and leveling equipment, machine tools, woodworking equipment for the furniture industry, and OEM machine tools.

This article was written by Diane Parpet of Belden Universal, Broadview, IL. For more information, please contact the company at .

Motion Control Technology Magazine

This article first appeared in the April, 2008 issue of Motion Control Technology Magazine.

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