Segmented Cam Shaft for Compact Clamping Device Drawbar Insertion
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Solution Overview
Problem
Existing clamping devices have a large drawbar cross-sectional dimension due to the need for accommodating a cam shaft with a sufficient cam formation, making it impossible to insert the drawbar through the housing bore from the forward end, resulting in larger device dimensions and increased manufacturing costs.
Innovation Solution
The cam shaft is designed with a first and second cam formation spaced by a circular cylindrical portion, allowing the drawbar to be inserted through the housing bore from the forward end by utilizing the same cam pitch for both formations, reducing the drawbar's cross-sectional dimension while maintaining sufficient strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the drawbar is made with a large cross sectional dimension to accommodate a cam shaft with sufficient cam formation, then the desired displacement and force reduction are achieved, but the drawbar cannot be inserted through the housing bore from the forward end
Solution Approach 1:
The cam shaft is segmented into two separate cam formations (first cam formation and second cam formation) spaced apart along the cam shaft axis. This segmentation allows each cam formation to be smaller in cross-section, enabling the drawbar to be inserted through the housing bore from the forward end while still providing sufficient displacement and force reduction through the combined action of both cam formations
Solution Approach 2:
The solution transitions from a single large cam formation to two smaller cam formations distributed along the longitudinal dimension of the cam shaft. By utilizing the longitudinal dimension to space the cam formations, the cross-sectional dimension is reduced, allowing the drawbar to pass through the housing bore while maintaining the necessary mechanical function
2Strength
If the drawbar is made with a large cross sectional dimension to ensure sufficient tensile strength, then the tool holder shank can be drawn with desirable forces, but the overall dimensions of the clamping device become larger
Solution Approach 1:
The cam shaft is divided into two cam formations spaced apart, which allows the drawbar to have a reduced cross-sectional dimension. This reduction enables the drawbar to be inserted through the housing bore from the forward end, resulting in a more compact overall dimension for the clamping device while maintaining sufficient tensile strength through the optimized drawbar design
Solution Approach 2:
The invention changes the geometric parameters of the cam shaft by distributing the cam function across two smaller cam formations rather than one large formation. This parameter change allows the drawbar aperture and drawbar cross-section to be reduced, enabling a more compact clamping device design that still provides the necessary tensile strength
3Force
If the drawbar is made with a large cross sectional dimension, then sufficient force reduction is achieved, but the cam shaft and drawbar aperture must be larger
Solution Approach 1:
The cam shaft is segmented into two cam formations (first and second cam formations) that are spaced apart along the cam shaft. This segmentation allows each individual cam formation to be smaller in cross-section, reducing the size of the drawbar aperture needed while still achieving sufficient force reduction through the combined mechanical advantage of both cam formations acting on the drawbar
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
Enables a more compact clamping device design with reduced manufacturing costs by allowing the drawbar to be inserted from the forward end, maintaining the necessary strength for tool holding and precision machining.
Implementation Method 1
a cam shaft extending through the drawbar aperture and comprising a cam formation, wherein the cam shaft is rotatably journalled in the housing and adapted to impart an axial displacement to the drawbar in relation to the housing by means of the cam formation when rotating the cam shaft
Data Source
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AI summary
The invention relates to a clamping device for releasably holding a tool holder shank (18) formed with a bore (14). The clamping device comprising a housing (13) having a forwardly facing surface and a bore, a drawbar (19) being mounted reciprocally movable inside the bore (14) and which in a forward end comprises engagement means (23) which is adapted to go into engagement with an engagement formation (47) inside the bore of the tool holder shank (18), the drawbar (19) being in a rear portion formed with a drawbar aperture (28) extending through the drawbar (19) in a transverse direction in relation to a longitudinal axis (27) of the same, and a cam shaft (16) extending through the drawbar aperture (28) and being rotatably journalled in the housing (13) and adapted to impart an axial displacement to the drawbar (19) in relation to the housing (13). According to the invention the cam shaft (16) comprises first and second spaced apart cam formations (34, 35) and an intermediate circular cylindrical portion (36) located between the cam formations (34,35), wherein the first and second cam formations are journalled in a first and second seating apertures, respectively, in the housing (13) on opposite sides of the drawbar (19), whereas the intermediate circular cylindrical portion (36) is extended through the drawbar aperture (28), and wherein the drawbar (19) is insertable into the bore (14) through the forwardly facing surface.