Embedded Files
Previous Design Prototype by 2013 Bio-engineering Students
Possible Improvements
Time taken to completely mount surgical blades
Depth of hook and slits to hold blades firmer into place
A way to keep the first blade in place before proceeding to mount the second blade
Safety while mounting blades
Characteristics
The prototype consists of a double-hook rod, a handle, and a screw cap.
The two hooks face opposite directions and are used to hold the blades in place.
There are slits in the hollow handle that allows the blades to stand vertically.
A threaded section on the rod allows the rod to be to tightened or loosened using a screw cap.
Annotated CAD Figure of Previous Prototype
Previously Considered Designs by the Team
Design 1 - Slot and Pin Design
Characteristics
Blades sit snugly into the slits on the handle that are 4 mm apart.
The pin acts as a catch when mounting the blades.
The inner rod pushes against the blades onto the pin from below, creating constraining force on the blade.
An O-ring would be used together with the end cap to secure the placement of the inner rod after constraining the blades.
Benefits
Blade is constrained and tightly held by the clamping mechanism
Pin acts as catch to keep first blade in place while mounting the second one
Concerns
Inclusion of an extra part in the mechanism (Pin)
Pin is small and might be misplaced easily
Constant contact with blade while mounting
Cutting surface available is reduced
Design 2 - Collet and Collar Design
Annotated CAD Image of Slot and Pin Design
Benefits
Easy to change blades
Mounting procedure is safe
Concerns
Difficulty of manufacture
Parallelism of blades
Characteristics
This design is based on the well known X-Acto knife blade
It uses a collet to secure the two blades in place
CAD Images of Collet and Collar Design
Design 3 - Modular Design
Characteristics
Modeled after Insulin pens
Benefits
Mounting procedure is safe
Concerns
Produces a lot of waste
Does not solve key concerns such as the parallelism of blades
Design 4 - Side Clamp Design
CAD Image of Modular Design
Characteristics
Uses a screw, spacers, and a wingnut to secure blades in place.
A spacer is used to separate the blades to the desired amount.
Spacers with different thicknesses allow for variable cutting thickness.
Movement of the blade in the horizontal plane is constrained with a secondary spacer and wingnut.
End of the blade rests snugly on the handle base, constraining the blade on the vertical plane.
Benefits
Mounting procedure is safe
Blades are parallel
Concerns
Takes up too much time to mount
Too many parts involved
Annotated CAD Images of Side Clamp Design
Design 5 - Wedge Collet Design
Concerns
Sockets may get lost easily
Cutting length may be too short
Pugh Chart
Characteristics
As the shaft being held upside down, the two blades would slide into the wedges vertically.
While the blades are sitting in the wedges due to gravity, two sockets would follow the same track to slide into the wedges and squeeze the blades.
As both the blades and sockets are in position, the collet would be tightened along the threaded shaft and pushes the sockets.
By applying force vertically on the sockets, they would also squeeze horizontally due to the design.
Benefits
Annotated CAD Images of Wedge Collet Design
Blades are kept parallel
Blade mounting is fast and safe
Pugh Chart with Weights that reflect the Functional Requirements of the Project
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