Helix - Revision history

DT Online at 19:27, 2 June 2016

2016-06-02T19:27:38Z

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	=====~~Construction~~=====		=====Constructions=====

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2016-06-02T19:04:51Z

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			__TOC__


			=====Description=====

	A [https://en.wikipedia.org/wiki/Helix '''Helix'''] is the '''[[Loci\|locus of a point]]''' travelling with '''[[Types of Motion\|constant linear velocity]]''', axially along the outside of a cylinder as the cylinder rotates with '''[[Types of Motion\|constant angular velocity]]'''. The axial distance travelled by the point for each revolution of the cylinder is known as the '''''pitch'''''.		A [https://en.wikipedia.org/wiki/Helix '''Helix'''] is the '''[[Loci\|locus of a point]]''' travelling with '''[[Types of Motion\|constant linear velocity]]''', axially along the outside of a cylinder as the cylinder rotates with '''[[Types of Motion\|constant angular velocity]]'''. The axial distance travelled by the point for each revolution of the cylinder is known as the '''''pitch'''''.

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	The elevation of this locus is a '''[[Types of Motion\|Sine Curve]]''', which is also the curve used on a '''[[Displacement Diagram]]''' to generate '''[[Types of Motion\|Simple Harmonic Motion]]''' to a '''[[Radial Cam\|Cam Follower]]'''.		The elevation of this locus is a '''[[Types of Motion\|Sine Curve]]''', which is also the curve used on a '''[[Displacement Diagram]]''' to generate '''[[Types of Motion\|Simple Harmonic Motion]]''' to a '''[[Radial Cam\|Cam Follower]]'''.


			=====Construction=====

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			{{Drawing Instruments Buyers Guide}}


	[[Category:Secondary]]		[[Category:Secondary]]
	[[Category:Geometry]]		[[Category:Geometry]]

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2015-02-21T15:47:50Z

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	* Continue for all other points then sketch a fair curve through them to create the helix ''(or use [https://en.wikipedia.org/wiki/French_curve '''French Curves'''] or a [https://en.wikipedia.org/wiki/Flat_spline '''flexible strip'''] for example)''		* Continue for all other points then sketch a fair curve through them to create the helix ''(or use [https://en.wikipedia.org/wiki/French_curve '''French Curves'''] or a [https://en.wikipedia.org/wiki/Flat_spline '''flexible strip'''] for example)''
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	\| [[File:~~Helix1~~.~~jpg~~\|350px\|right]]		\| [[File:HelixConstruction.png\|350px\|right]]
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	\| '''Drawing Helical Screws and Springs'''		\| '''Drawing Helical Screws and Springs'''
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	* Careful visualisation and selection of which parts of the helixes are in front and which are hidden will then enable a 3D screw-type form to be completed.		* Careful visualisation and selection of which parts of the helixes are in front and which are hidden will then enable a 3D screw-type form to be completed.
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	\| [[File:~~Helix2~~.~~jpg~~\|350px\|right]]		\| [[File:HelicalScrew.png\|350px\|right]]
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DT Online: Created Helix

2015-02-19T18:21:05Z

Created Helix

New page

A [https://en.wikipedia.org/wiki/Helix '''Helix'''] is the '''[[Loci|locus of a point]]''' travelling with '''[[Types of Motion|constant linear velocity]]''', axially along the outside of a cylinder as the cylinder rotates with '''[[Types of Motion|constant angular velocity]]'''. The axial distance travelled by the point for each revolution of the cylinder is known as the '''''pitch'''''.

A helix is the curve used to produce a '''[[Basic Machines|screw]]''' and is common in [https://en.wikipedia.org/wiki/Screw '''screwthreads'''] and [https://en.wikipedia.org/wiki/Coil_spring '''coil springs'''].

The elevation of this locus is a '''[[Types of Motion|Sine Curve]]''', which is also the curve used on a '''[[Displacement Diagram]]''' to generate '''[[Types of Motion|Simple Harmonic Motion]]''' to a '''[[Radial Cam|Cam Follower]]'''.

{| cellpadding="5"
|-
| '''Drawing a Helix'''
| 
* Start by drawing a circle to represent the diameter of the generating cylinder and divide it into equal sectors ''(say,12)''
* Project horizontal lines along from each intersection between the radial dividing lines and the circle circumference.
* Make the length of these lines equal to the '''pitch''' of the helix to be drawn ''(or a mulitple of it if several ‘turns’ are needed)''.
* Start at 0 then plot Point 1 where the projection line from position 1 on the circle intersects the first vertical dividing line of the pitch as shown.
* Continue for all other points then sketch a fair curve through them to create the helix ''(or use [https://en.wikipedia.org/wiki/French_curve '''French Curves'''] or a [https://en.wikipedia.org/wiki/Flat_spline '''flexible strip'''] for example)''

| [[File:Helix1.jpg|350px|right]]
|-
| '''Drawing Helical Screws and Springs'''
| 
* Helical objects, such screwthreads and springs for example, are drawn in a similar way.
* Start by drawing two concentric circles: one equal to the outside diameter of the object and one equal to the inside diameter.
* Project horizontal lines from each circle as above and plot two helixes: one along the inner circle lines and one along those projected from the outer circle and sketch fair curves through these two to avoid confusion later.
* Choose a second starting point, furher along the pitch, and repeat to draw two more helixes as shown and sketch fair curves through them as before.
* Careful visualisation and selection of which parts of the helixes are in front and which are hidden will then enable a 3D screw-type form to be completed.

| [[File:Helix2.jpg|350px|right]]
|}
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'''Note:'''
To draw an actual thread or spring its cross-section must be drawn at the starting point 0 and this used to determine the inner ''(or ‘core’)'' diameter, the pitch, and the number of helixes required.

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[[Category:Secondary]]
[[Category:Geometry]]