Surgical Head Clamp with Ball Thread Spindle

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Solution Overview

Problem

Existing surgical head clamps with two-armed mandrel holders and two-part connecting webs are cumbersome to handle and adjust, making it difficult to achieve optimal fixation of a patient's head, and the threaded spindle is not freely movable.

Innovation Solution

A surgical head clamp design featuring a second mandrel holder with a plug-in bore and a threaded spindle with a ball thread that allows for axial adjustment and locking, enabling easier handling and adjustment, and allowing the threaded spindle to be freely movable by disengaging the balls from the thread, facilitating optimal clamping with two- or three-armed mandrel holders.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a two-armed mandrel holder is used on the head clamp, then the clamping capability is provided, but the handling and adjustment become cumbersome

Engineering Contradiction:
Improveclamping capabilityVSAvoidhandling and adjustment
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The mandrel holder is divided into a fixed arm and an adjustable arm that can be independently positioned. The adjustable arm can be separately adjusted along the connecting web, allowing each arm to be optimized for different clamping scenarios while simplifying the adjustment process compared to a rigid two-armed structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connecting web is designed as a two-part telescopic structure that can dynamically change its length. This allows the distance between the mandrel holder and the single mandrel to be continuously adjusted, providing adaptability for different patient head sizes while maintaining ease of operation through a simple extension mechanism

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If a two-part connecting web is used for rough distance adjustment, then the adaptability is improved, but the handling becomes cumbersome

Engineering Contradiction:
Improvedistance adjustment rangeVSAvoidhandling
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The connecting web employs a telescopic design with two parts that can extend and retract along their longitudinal axes. This dynamic structure provides a wide adjustment range for the distance between mandrels while maintaining simple handling through a straightforward extension mechanism without complex assemblies

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The connecting web serves multiple functions: it provides structural support between holder legs, enables rough distance adjustment through its telescopic capability, and maintains mechanical stability. This multi-functionality reduces the need for separate adjustment mechanisms, simplifying overall handling

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Stability of the object's composition

If the threaded spindle is fixed in the bearing bore, then the positioning stability is improved, but the adjustability is reduced

Engineering Contradiction:
Improvepositioning stabilityVSAvoidadjustability
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The threaded spindle is designed to be freely movable within the bearing bore, allowing dynamic adjustment of the mandrel holder position. The spindle can be inserted and removed from the bearing bore as needed, providing both adjustability during operation and stable positioning when engaged, eliminating the trade-off between stability and adaptability

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design simplifies handling and adjustment, allowing for precise and secure fixation of the patient's head with reduced risk of thread damage, as the threaded spindle can be positioned in various axial positions and fine adjustments made by turning, enhancing overall handling safety and ease.

Implementation Method 1

The external thread is designed as a ball thread with a profile similar to a segment of a circle, in which two balls engage as engagement elements

Methodology Applied
Scientific EffectBall thread mechanism: Ball

Implementation Method 2

the guide shaft, in which the mandrel holder is received, is resiliently mounted in the threaded spindle

Methodology Applied
Scientific EffectSpring pressure: Spring

Implementation Method 3

Located between this annular shoulder 63 and the stop shoulder 52 of the head part 51 is the compression spring 53 which encloses a part of the guide shaft 50 and which allows a certain spring stroke when a patient's head is clamped

Methodology Applied
Scientific EffectSpring compression: Spring

Data Source

PatentEP1849427B1Surgical head clamp
Publication Date: 2009.02.11 GOTTFRIED STORZ MEDIZINTECHN
  • EP1849427B1 patent drawingFigure 1~3
  • EP1849427B1 patent drawingFigure 4~10
  • EP1849427B1 patent drawingFigure 11

AI summary

The clamp is u-shaped (1) with bores at its outer ends (5, 6) holding clamping elements (12), each provided with three spikes (14) at the front. A first element comprises a movable spike holding plate (15) located close to the arm of the device (1), while the second element is attached to the front of a spindle (10) with a ball thread acting in combination with two spheres positioned opposite each other in recesses at the inner surface of a bearing and kept in a locked position by a catch (35).