Surgical Instrument Crank Mechanism for Angled Manipulation
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Solution Overview
Problem
Laparoscopic instruments face limitations in maneuverability due to restricted degrees of freedom, which can cause tissue damage and require complex systems with delicate wires that fail under repeated sterilization, affecting dexterity and reusability.
Innovation Solution
A surgical instrument design featuring a distal tool head, a proximal handle, and a central system with a universal joint and series of linked parts providing multiple degrees of freedom, eliminating the need for wires and pulleys by using a crank and collar mechanism for angular displacement and transverse movement, allowing precise control and locking of the head portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional laparoscopic instruments with restricted degrees of freedom are used, then the structure is simple, but the maneuverability is limited and tissue damage may occur
Solution Approach 1:
The instrument is divided into multiple independent segments: a body portion, a head portion, a rotator mechanism, and a universal joint. Each segment can move independently about distinct axes, allowing the head to achieve complex orientations through coordinated movement of segments rather than requiring a single complex joint
Solution Approach 2:
The instrument transitions from restricted movement in limited dimensions to multi-dimensional movement by adding rotational freedom about multiple distinct axes. The universal joint and rotator enable the head portion to move not only linearly but also angularly in multiple directions, adding spatial dimensions to the operational capability
2Ease of operation
If complex systems with wires and pulleys are used to increase degrees of freedom, then maneuverability improves, but reliability decreases due to wire failure under sterilization
Solution Approach 1:
The design extracts and eliminates the wire and pulley components from the system. Instead of using flexible wires that pass through pulleys to control the end effector, the invention uses a rigid mechanical linkage system with direct mechanical connections between the handle, rotator, universal joint, and head portion, removing the failure-prone wire elements
Solution Approach 2:
The flexible wire-mechanical pulley system is replaced with a rigid mechanical linkage system. The control is achieved through direct mechanical coupling of shafts, cranks, and joints that transmit force and motion through solid mechanical connections rather than flexible wires, improving durability under sterilization conditions
3Adaptability or versatility
If instruments with limited degrees of freedom are used, then the device complexity is low, but the ability to perform angled operations in body cavities is restricted
Solution Approach 1:
The universal joint serves multiple functions: it accommodates angular movement from the rotator, allows the head to orient in multiple directions, and maintains mechanical coupling between components. This single multi-functional joint replaces what would otherwise require multiple specialized mechanisms, achieving versatility without proportional increases in complexity
Solution Approach 2:
The instrument incorporates dynamic movement capabilities where the head portion can change its orientation and angular position during operation. The rotator and universal joint enable the system to adapt its configuration dynamically rather than being fixed in a single orientation, allowing angled operations while maintaining a relatively compact mechanism
Data Source
AI summary
Surgical instruments are movable in several different dimensions and about several distinct axes. Surgical instruments include a head portion having a desired tool, a body portion freely moveable in several dimensions with respect to the head to which it connects via a connection or joint, which may be maneuverable and lockable in several head-body orientations. The connection may include one or more cooperative shafts, a rotator that angularly moves the head portion, a joint that translates the angular motion from rotator to the head in any relative orientation of the head portion, a crank that couples the shafts with the head portion, and a collar having an end slot to accommodate one or more of the shafts. In this way, as the shaft moves upward and downward, the head portion is transverse angularly displaced.