Cross Sectional View
Design Background
The tool attachment was designed to interface with an existing 90° screw insertion tool used for minimally invasive rib plate fixations. The advantage of this attachment is its compatibility with a powered hand piece rather than a screwdriver handle, which is how insertions are traditionally performed. This allows for shorter surgery time and ease of use on the surgeons side.
Design Concept
This simple design concept consists of a drive shaft interfacing with the powered hand piece on one end and the existing 90° screw insertion tool on the other. Encasing this drive shaft in a housing held in by just a spiral clip makes this assembly very easy to put together. Two bearings, one at each end of the shaft, help align the drive shaft in the housing and prevents any unnecessary runout, which may cause improper engagement between parts.
Exploded View
Production Attachment
Design Analysis
The solid shaft design, in combination with customer design constraints, required extensive tolerance analysis to ensure proper assembly engagement and prevent slipping. Since the gear set up from the customer piece caused low speeds and high torques on the drive shafts, further analysis was conducted on the press fit needed to hold the coupler between the attachment and the customer tool. Inserting a press fitted stainless steel pin through the coupler and shaft helped alleviate the shear force previously applied solely to the press fit.