I believe this project went well and that we worked well as a team. We remained on schedule for the first stage and , due to continuous work from the group over the Easter holidays, were able to complete the project on time despite some set backs.
The greatest problem we faced was that two of our group members were missing for approximately three weeks each at different stages of the project. Our materials specialist was absent due to illness at the start of the project, and our stress analyst was not contactable over the Easter holidays due to a breakdown in communication. The remaining group members however worked well around these losses and those who did miss part of the project worked hard upon their return to make up for their loss, in order to produce the final crane to a high standard.
The second set back occurred towards the start of the Easter break when it was realised that the main beam needed redesigning. This set us back about a week, though did give us the opportunity to redesign the beam to British standard dimensions.
The greatest flaw in the design that was picked up in the Q&A section of the presentation was that the beam, at 5.5 metres in length, was on the border of being impractically large. This was a problem that we had considered, though splitting the beam would have weakened it significantly. If I had more time for this project , I would spend much of it considering possible solutions to splitting the beam. In addition, the design of the head piece of the shoulder component would be difficult to manufacture for a reasonable cost.
In conclusion, though we had a few issues, I believe this project was a success, and that we completed it to a high standard as well as to specification.
Showing posts with label Mark Hawkins. Show all posts
Showing posts with label Mark Hawkins. Show all posts
Friday, 30 April 2010
Thursday, 29 April 2010
Exploded crane animation
This is the animation describing the assembly of the crane.
The colour scheme is arbitrary in this video, designed to allow the viewer to differentiate easily between components.
Safety - Tools
It is highly advisable to tighten the U-bolts by hand with a spanner rather than with a torsion torsion wench. It is also advisable to use a spirit level to ensure that the beam is horizontal before loading the crane to minimise the chances of the hoist slipping along the beam.
Sunday, 25 April 2010
Company Name and Logo
The company name chosen was Dynamic Engineering Solutions (DES). This name is both memorable and slightly amusing, though the comical effect wears off the more one hears it thus allowing are clients to take our company seriously once the initial attention catching humour wears off. The logo chosen utilises primary colours in order to grab attention in an aesthetically pleasing manor. The image below shows the logo for official correspondence.
The final orientation of the company logo is the squared off version design to be placed on CAD drawings and on our products. This logo, depicted below, is both bold and instantly recognisable. It is designed so that perspective clients will be attracted to our company when they see it in the field.
The company motto will be added to this design for our advertising. The motto required a short, memorable, and to-the-point sentence to sum up our companies values, and inspire the trust of our perspective clients.
The motto chosen was "just ask DES", which was designed to imply that we shall go above and beyond to satisfy our clients needs whatever they may be. The image below depicts the company logo with the motto attached.
The final orientation of the company logo is the squared off version design to be placed on CAD drawings and on our products. This logo, depicted below, is both bold and instantly recognisable. It is designed so that perspective clients will be attracted to our company when they see it in the field.
Saturday, 24 April 2010
Formal Engineering Drawings Templates
The follow image is the engineering drawing template for the crane components. The company logo is yet to be inserted, but all other elements are as they will be in the formal proposal.
The next image is of the engineering drawing template for the crane assemblies, one will be standard and the other one will be exploded.
This drawing template also requires the company logo, though is also otherwise as the final assembly drawings will be presented.
The blue text represents links to the part designs, which will be automatically replaced with the appropriate information.
The next image is of the engineering drawing template for the crane assemblies, one will be standard and the other one will be exploded.This drawing template also requires the company logo, though is also otherwise as the final assembly drawings will be presented.The blue text represents links to the part designs, which will be automatically replaced with the appropriate information.
Thursday, 22 April 2010
Machining Cost
One of the questions that needs to be answered is how much it is going to cos to make the crane. The beam is of a standard design and can be purchased pre-made and cut to the required length. However the legs must be specially made and a machining cost must be evaluated.
First and foremost we must look at the different types of tools that could be used to cut the aluminium into the specified dimensions.
High Speed Steel
This material was invented in the 19th century and was a massive improvement on the standard cutting tools of that time since they can function under higher speeds and hotter temperatures than standard steel tools. Out of all the tools researched this has the lowest range of cutting speeds, however it is still able to cut aluminium to a rough finish, but the life of the tool is significantly small when cutting this material. However the material is the cheapest type of tools looked at.
Cast Alloys
This material is a standard base metal (e.g. iron) which has been augmented with an alloying element (e.g. nickel, tungsten, chromium etc.). The reason for doing this is to improve the metals strength and reaction to heat. This group of cutting tools can operate at higher cutting speeds and temperatures than High Speed Steel, and the tool life is significantly higher. The price of these tools are also quite reasonable.
Carbides
Strong metal such as titanium are part of the this group of materials, and are used in some of the most extreme situations, for example they are used to construct the fuselage of space shuttles which are put under the most extreme temperature any material could be put through. In relation to cutting tools, this material is second only to certain ceramics in cutting speed and operating temperatures. The pieces are highly expensive though.
Price for Cast Alloy cutting tools = approx £20.00 (set of 11 cutting tools)
source: axminster tool centre
Ceramics
As mentioned before this the type of cutting tool that is second to none. Ceramic is the name given to most crystalline oxide structures, such as silicon carbide, saolin, titanium carbide. The strength of this material has been proven through the use in space shuttle re-entry shields, military ballistic vests, and heavy duty abrasives. Yet, as said with the carbides ceramics are very expensive to produce so the tool prices are very dear, but the tool life balances that out quite well.
By looking at this research it can be said that for the current project using Cast Alloy tools would be the most beneficial to the production of the cranes.
area of aluminium = 1.88 m^2
cutting speed = 1.1-1.8 m/sec (66-108 m/min)
life of cutting tool when cutting to a finished result = approx 175 mins
cost per cutting tool = £20/11 = £1.82 per tool
tool cost = £1.8/175mins = £0.01/min
minimum wage of machine operator = £6/per hour = £0.1/min
Machining Cost = Co x tm
Co = operator wage + overhead
overhead = life of tool + material able to be cut by tool per minute
tm = amount of time needed for task to be completed
Machining Cost = £241 per/min
This is quite a reasonable cost seing as the amount of material that can be machined within a minute will make up multiple kits.
source of calculations: Handbook of Material Selection, Myek Kutz, 2002 edition, published by John Wiley & Sons New York.
other sources:
Saturday, 17 April 2010
Exploded Third Crane Design
The image below shows the exploded view of the third and final crane design. This image also contains a list of components and their quantities.
Tuesday, 13 April 2010
Crane Foot Base Options
The following image is a rendered picture of four potential crane foot base options.
These foot bases will be analysed from left to right:
- The first is the original foot base, as described by the previous CAD drawings. This foot base is quite basic and versatile, though since it will be supporting the crane foot on an angle it may be prone to slippage in wet conditions.
- The second is a revised foot base. This foot base has been slanted to the angle of the crane foot. The bottom has also been altered to have a series of groves, increasing the friction of the foot base with the ground. This design would greatly improve the stability of the crane, though would require a small flat surface to rest upon. It would also require orientating to the angle of the crane foot.
- The third design is a modified version of the previous design with all the same benefits over the original design. However this design has a reduced surface area of contact, thus the area beneath the foot base need not be as flat. This however may slightly reduce the stability of the crane, and this type also requires orientating.
- The final design is a spike design. This would be particularly useful in soft ground to help anchor the crane, however it would be useless on a solid surface such as concrete or tarmac.
In conclusion, I believe that since these foot bases have been designed to be removable, multiple types should be provided in the pack to suit different situations. I will take this matter up with the rest of the team in the next group meeting.
These foot bases will be analysed from left to right:
- The first is the original foot base, as described by the previous CAD drawings. This foot base is quite basic and versatile, though since it will be supporting the crane foot on an angle it may be prone to slippage in wet conditions.
- The second is a revised foot base. This foot base has been slanted to the angle of the crane foot. The bottom has also been altered to have a series of groves, increasing the friction of the foot base with the ground. This design would greatly improve the stability of the crane, though would require a small flat surface to rest upon. It would also require orientating to the angle of the crane foot.
- The third design is a modified version of the previous design with all the same benefits over the original design. However this design has a reduced surface area of contact, thus the area beneath the foot base need not be as flat. This however may slightly reduce the stability of the crane, and this type also requires orientating.
- The final design is a spike design. This would be particularly useful in soft ground to help anchor the crane, however it would be useless on a solid surface such as concrete or tarmac.
In conclusion, I believe that since these foot bases have been designed to be removable, multiple types should be provided in the pack to suit different situations. I will take this matter up with the rest of the team in the next group meeting.
Monday, 12 April 2010
Clevis Pin Types
Having chosen Clevis Pins as the type of beam pins, it is now important to decide on a type of pin. It would be of benefit if all pins and bolts in the kit were the same, thus reducing assembly time as any bolt would fit any hole.
The image below shows a selection of pin types. The most appropriate for this crane would be either the SAE pin or the Bent pin. Once the stress analysis on the legs has been completed I shall use that information to select an appropriate standard pin for this crane.
http://www.huyett.com/catalog/index.php?cPath=21_30&gclid=CLWA-cbKgaECFSEulAod7wabuA
The image below shows a selection of pin types. The most appropriate for this crane would be either the SAE pin or the Bent pin. Once the stress analysis on the legs has been completed I shall use that information to select an appropriate standard pin for this crane.
http://www.huyett.com/catalog/index.php?cPath=21_30&gclid=CLWA-cbKgaECFSEulAod7wabuA
Painting Safety Note
It is worth noting that since the legs are made from aluminium, it is necessary to adopt caution when choosing a primer paint. The following formula describes the oxidation of aluminium:
Fe2O3 + 2Al → 2Fe + Al2O3 + heat
When ignited, this reaction of aluminium and iron oxide produces liquid iron which can melt though almost anything. The military would call such a mixture thermite, and it would be used in incendiary devices.
This reaction would occur if the crane legs were painted with an iron oxide based primer paint such as Red Oxide. This particular type of paint is a common primer when painting metals, however it would be highly inappropriate to paint aluminium with it in a disaster zone where there would like be many large and uncontrolled fires.
The type of primer more suited to this environment would be an Epoxy Mastic metal primer or similar.
Fe2O3 + 2Al → 2Fe + Al2O3 + heat
When ignited, this reaction of aluminium and iron oxide produces liquid iron which can melt though almost anything. The military would call such a mixture thermite, and it would be used in incendiary devices.
This reaction would occur if the crane legs were painted with an iron oxide based primer paint such as Red Oxide. This particular type of paint is a common primer when painting metals, however it would be highly inappropriate to paint aluminium with it in a disaster zone where there would like be many large and uncontrolled fires.
The type of primer more suited to this environment would be an Epoxy Mastic metal primer or similar.
Potential Changes to Third Shoulder Design
The following image describes three possibilities for the third crane shoulder.
They are as follows:
-The one on the left is the design described in detail in my previous post
-The middle one is the same as the first, only with the top removed. This would reduce manufacturing cost and weight, though as the anchoring system of the shoulder to the beam is now essientially an open system, this woyuld significantly decrease the strength.
-The one on the right is a box design, essentially the same as the first design except in one solid block. This would increase the stability of the anchoring of the beam into the shoulder, though at the same time would significantly increase the cost of manufacture and the weight of the leg as a whole.
In conclusion I believe the original design is the most suitable, though in order to be certain this requires farther stress analysis to find the best design.
They are as follows:
-The one on the left is the design described in detail in my previous post
-The middle one is the same as the first, only with the top removed. This would reduce manufacturing cost and weight, though as the anchoring system of the shoulder to the beam is now essientially an open system, this woyuld significantly decrease the strength.
-The one on the right is a box design, essentially the same as the first design except in one solid block. This would increase the stability of the anchoring of the beam into the shoulder, though at the same time would significantly increase the cost of manufacture and the weight of the leg as a whole.
In conclusion I believe the original design is the most suitable, though in order to be certain this requires farther stress analysis to find the best design.
Sunday, 11 April 2010
Third Crane Shoulder Design
This is the third design for the crane shoulder. The dimensions have been altered to fit the UB178x102x19 beam. The dimensions of the holes for the pins are currently arbitrary as I am awaiting the pin analysis, however all other elements are dimensioned correctly.
The following image is a comparison between the second (pictured to the left) and third (to the right) shoulder design.
This third design is described in more detail in the engineering drawing below.
The crane is now slightly taller than before, though with this standardised beam will have far more options concerning the choice of winch mechanism. The image below describes the assembled crane, without the beam pins.
Friday, 9 April 2010
Preliminary Research on Potential Beam Pins
Introduction
In this post I will examine the potential of Hex bolts, Clevis pins, and U bolts for the application of becoming the crane pin component. I will use preliminary research to identify strengths and weaknesses of each type, and attempt to draw a conclusion of which one to investigate in more detail.
HEX Bolts
The bolts used for the crane must be a standard dimension and strong enough to withstand the forces applied when the crane is loaded. The first image is of the standard bolt measurement system and the second is of a table of standard dimensions and strengths. Note that the dimensions shown are all prior to coating and thus slightly undersized, and that all images were obtained from the same article which is referenced at the end.
This article also dealt with nuts and washers. The information is shown in the images below and will be used as a start point in finding the ideal bolt/washer/nut combination should the group decide to use HEX bolts for the crane pins.
http://www.mbw.co.uk/documents/factsheets/Non-Preload.pdf
The material that the bolts are made from also contributes considerably to their yield strengths. The following table was taken from a manufacturers website and applies to M16 HEX bolts. Further research will be conducted to assist the group in deciding the type and size of crane pin to use.
http://www.boltdepot.com/fastener-information/Materials-and-Grades/Bolt-Grade-Chart.aspx
In conclusion, this preliminary research shows that HEX bolts do have potential for use as our crane pins. Depending on the type they have yield strengths of approximately of the order of 100MPa, have many optional standard dimensions, and are cheap to purchase (~£1 per unit referenced below). There may be an issue with the numbers of small washers and nuts that would be required however, as these may easily be lost in a disaster relief environment.
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=retrieveTfg&Ne=4294957938&Nr=AND%28avl%3auk%2csearchDiscon_uk%3aN%29&N=4294962569+4294955562+4294905479&Ns=stockPolicy_uk%7c1%7c%7cnew_uk%7c1&binCount=85&multiselectParam=4294962569%204294955562&selectAttribute=M20#breadCrumb
Clevis Pins
Clevis pins are ideal for fast assembly situations such as with this emergency crane. The pin slots in the hole and is fastened by a split pin or similar. The table below, sourced from a manufacturers website, details the dimensions of some standard Clevis pins.
http://www.automotioncomponents.co.uk/purchase.php?p_no=P1242
The pins may be fixed in a variety of ways such as split pins, hitch pins, and linch pins. The image below shows a section of different connection types for Clevis pins.
http://www.automotioncomponents.co.uk/purchase.php?p_no=P1242
In conclusion, Clevis pins are a better option than HEX bolts. The cost and yield strengths of the Clevis pins are approximately the same as for the HEX bolts, though they are considerable quicker to assemble and do not require washers.
U Bolts
U bolts are slightly stronger than Hex bolts or Clevis pins as they fit two holes connected in pairs. They have a slight advantage over the HEX bolts as their washers may also be doubled up, as depicted below.
www.sea-sure.co.uk/ubolt2.htm
There are many different designs of U bolt, the two main types of which are shown below, though for the application of the emergency crane the square bend U bolt is most appropriate.
http://www.clampsinc.com/guidelines%20for%20ubolts.htm#COLD%20DRAWING%20AND%20BOLT%20STRENGTH
In conclusion, U bolts would be better than HEX bolts as they require fewer washers. They also cost only slightly more than Hex bolts or Clevis pins, meaning that overall they are the cheapest option as one would only require half as many of them for the crane as a whole.
Summary
HEX Bolts:
Strength - Acceptable
Price - Moderate
Speed of Assembly - Slow
Number of Parts - High
Clevis Pins:
Strength - Acceptable
Price - Moderate
Speed of Assembly - Fast
Number of Parts - Low
U Bolts:
Strength - High
Price - Low
Speed of Assembly - Slow
Number of Parts - Moderate
Conclusion
The HEX bolts are not appropriate for this crane. They have too many small parts and a system using them would require too much time to assemble in an emergency situation. The U bolts are the cheapest and strongest, though the number of small parts which may be lost and the speed of assembly mean they would not be appropriate either.
Therefore I conclude that Clevis pins are the most appropriate pins for this emergency crane. They are reasonably priced, they are fast to assemble, and they have the least number of components of the crane pin types considered.
In this post I will examine the potential of Hex bolts, Clevis pins, and U bolts for the application of becoming the crane pin component. I will use preliminary research to identify strengths and weaknesses of each type, and attempt to draw a conclusion of which one to investigate in more detail.
HEX Bolts
The bolts used for the crane must be a standard dimension and strong enough to withstand the forces applied when the crane is loaded. The first image is of the standard bolt measurement system and the second is of a table of standard dimensions and strengths. Note that the dimensions shown are all prior to coating and thus slightly undersized, and that all images were obtained from the same article which is referenced at the end.
This article also dealt with nuts and washers. The information is shown in the images below and will be used as a start point in finding the ideal bolt/washer/nut combination should the group decide to use HEX bolts for the crane pins.
http://www.mbw.co.uk/documents/factsheets/Non-Preload.pdf
The material that the bolts are made from also contributes considerably to their yield strengths. The following table was taken from a manufacturers website and applies to M16 HEX bolts. Further research will be conducted to assist the group in deciding the type and size of crane pin to use.
http://www.boltdepot.com/fastener-information/Materials-and-Grades/Bolt-Grade-Chart.aspx
In conclusion, this preliminary research shows that HEX bolts do have potential for use as our crane pins. Depending on the type they have yield strengths of approximately of the order of 100MPa, have many optional standard dimensions, and are cheap to purchase (~£1 per unit referenced below). There may be an issue with the numbers of small washers and nuts that would be required however, as these may easily be lost in a disaster relief environment.
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=retrieveTfg&Ne=4294957938&Nr=AND%28avl%3auk%2csearchDiscon_uk%3aN%29&N=4294962569+4294955562+4294905479&Ns=stockPolicy_uk%7c1%7c%7cnew_uk%7c1&binCount=85&multiselectParam=4294962569%204294955562&selectAttribute=M20#breadCrumb
Clevis Pins
Clevis pins are ideal for fast assembly situations such as with this emergency crane. The pin slots in the hole and is fastened by a split pin or similar. The table below, sourced from a manufacturers website, details the dimensions of some standard Clevis pins.
http://www.automotioncomponents.co.uk/purchase.php?p_no=P1242
The pins may be fixed in a variety of ways such as split pins, hitch pins, and linch pins. The image below shows a section of different connection types for Clevis pins.
http://www.automotioncomponents.co.uk/purchase.php?p_no=P1242
In conclusion, Clevis pins are a better option than HEX bolts. The cost and yield strengths of the Clevis pins are approximately the same as for the HEX bolts, though they are considerable quicker to assemble and do not require washers.
U Bolts
U bolts are slightly stronger than Hex bolts or Clevis pins as they fit two holes connected in pairs. They have a slight advantage over the HEX bolts as their washers may also be doubled up, as depicted below.
www.sea-sure.co.uk/ubolt2.htm
There are many different designs of U bolt, the two main types of which are shown below, though for the application of the emergency crane the square bend U bolt is most appropriate.
http://www.clampsinc.com/guidelines%20for%20ubolts.htm#COLD%20DRAWING%20AND%20BOLT%20STRENGTH
In conclusion, U bolts would be better than HEX bolts as they require fewer washers. They also cost only slightly more than Hex bolts or Clevis pins, meaning that overall they are the cheapest option as one would only require half as many of them for the crane as a whole.
Summary
HEX Bolts:
Strength - Acceptable
Price - Moderate
Speed of Assembly - Slow
Number of Parts - High
Clevis Pins:
Strength - Acceptable
Price - Moderate
Speed of Assembly - Fast
Number of Parts - Low
U Bolts:
Strength - High
Price - Low
Speed of Assembly - Slow
Number of Parts - Moderate
Conclusion
The HEX bolts are not appropriate for this crane. They have too many small parts and a system using them would require too much time to assemble in an emergency situation. The U bolts are the cheapest and strongest, though the number of small parts which may be lost and the speed of assembly mean they would not be appropriate either.
Therefore I conclude that Clevis pins are the most appropriate pins for this emergency crane. They are reasonably priced, they are fast to assemble, and they have the least number of components of the crane pin types considered.
CAD UB178x102x19 Crane Beam
These are the CAD images and drawings of the UB178x102x19 Crane Beam. Firstly we have an image of the revised crane beam (left of image) compared to the UB178x102x19 Crane Beam (right of image).
In addition, here is the engineering drawing for this standard beam. The holes for the beam pins are M20 and just over three times the distance from the end of the beam as their diameter.
The use of a standard dimensioned beam will dramatically reduce cost, compared with a custom beam, and also make it considerably easier to find a winch system to fit the beam dimensions.
In addition, here is the engineering drawing for this standard beam. The holes for the beam pins are M20 and just over three times the distance from the end of the beam as their diameter.
The use of a standard dimensioned beam will dramatically reduce cost, compared with a custom beam, and also make it considerably easier to find a winch system to fit the beam dimensions.
Beam pins
The beam pins are inefficiently designed, and will be changed on CAD shortly. They will be altered to a standard size HEX head bolt, such as one from the list show on the following link, to considerably reduce their cost in comparison to the cost of custom made pins.
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=retrieveTfg&Ne=4294957938&Nr=AND%28avl%3auk%2csearchDiscon_uk%3aN%29&N=4294962569+4294955562+4294905479&Ns=stockPolicy_uk%7c1%7c%7cnew_uk%7c1&binCount=85&multiselectParam=4294962569%204294955562&selectAttribute=M20#breadCrumb
Another option for the pin design is to use a Clevis pin system
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=browseSubRange&Ne=4294953839&N=4294947005&productNum=0838940
Alternatively, to reduce the number of components in the crane pack (as small parts may be lost) a U bolt system could be employed
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=retrieveTfg&binCount=7&Ne=4294957561&Ntt=u+bolt&Ntk=I18NAll&Nr=AND%28avl%3auk%2csearchDiscon_uk%3aN%29&Ntx=mode%2bmatchallpartial&N=4294955388&Nty=1
The beam dimensions have once again been altered and so a revised CAD representation will also be posted here shortly, as well as any other changes to the design proposed by the stress analysis (including limits and fits which will be added as they are calculated)
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=retrieveTfg&Ne=4294957938&Nr=AND%28avl%3auk%2csearchDiscon_uk%3aN%29&N=4294962569+4294955562+4294905479&Ns=stockPolicy_uk%7c1%7c%7cnew_uk%7c1&binCount=85&multiselectParam=4294962569%204294955562&selectAttribute=M20#breadCrumb
Another option for the pin design is to use a Clevis pin system
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=browseSubRange&Ne=4294953839&N=4294947005&productNum=0838940
Alternatively, to reduce the number of components in the crane pack (as small parts may be lost) a U bolt system could be employed
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=retrieveTfg&binCount=7&Ne=4294957561&Ntt=u+bolt&Ntk=I18NAll&Nr=AND%28avl%3auk%2csearchDiscon_uk%3aN%29&Ntx=mode%2bmatchallpartial&N=4294955388&Nty=1
The beam dimensions have once again been altered and so a revised CAD representation will also be posted here shortly, as well as any other changes to the design proposed by the stress analysis (including limits and fits which will be added as they are calculated)
Tuesday, 30 March 2010
Mark Hawkins - General Formula for Beam Dimensions
In order to assist with the stress analysis and beam design, I have created this general formula to calculate the beam dimensions in relation to each other for different materials.
Wednesday, 24 March 2010
Mark Hawkins - Second Design CAD Drawings
The following are the CAD drawings for the components of this second design. The first image is of this crane assembled, and the next ten are the individual components. The last sheet is an assembly sheet showing how the crane goes together.
The dimensions and angles described by these designs have been calculated by the stress analyst, though they are still awaiting materials analysis and corresponding approval from finance. Once these tasks have been completed, the materials information will be added to the drawings and any final alterations will be made.
The dimensions and angles described by these designs have been calculated by the stress analyst, though they are still awaiting materials analysis and corresponding approval from finance. Once these tasks have been completed, the materials information will be added to the drawings and any final alterations will be made.
Mark Hawkins - Second Design Revision
This revision of the design had two objectives, firstly was to simplify the joint on the leg design, and secondly to redesign the beam to the stress analyst's specifications.In all images the original design is to the left, and the revised design is to the right.
The ball joint in the leg was replaced with a much simpler structure in order that the manufacturing costs could be reduced. The image below depicts this change.
The next change was the beam. The stress analyst decided that the best beam design was an I beam as depicted below. The dimensions are no longer arbitrary for all designs, but as calculated by the stress analyst.
In order to fit this new beam to the structure, the shoulder and beam pins also required redesigning. The head of the shoulder was reshaped and the pins were lengthened as shown below.
The design is now complete, pending analysis by finance, and full engineering drawings will be posted here shortly.
The ball joint in the leg was replaced with a much simpler structure in order that the manufacturing costs could be reduced. The image below depicts this change.
The next change was the beam. The stress analyst decided that the best beam design was an I beam as depicted below. The dimensions are no longer arbitrary for all designs, but as calculated by the stress analyst.
In order to fit this new beam to the structure, the shoulder and beam pins also required redesigning. The head of the shoulder was reshaped and the pins were lengthened as shown below.
The design is now complete, pending analysis by finance, and full engineering drawings will be posted here shortly.
Tuesday, 23 March 2010
Meeting 7 (22/03/2010)
All members were present for this meeting
In this meeting we discussed the current market prices and strengths/weaknesses of materials, and whether or not they should be used in the design. The stess analysist completed his analysis and handed the revised dimensions to the chief designer.
For the next meeting the designer will have completed the final CAD drawings and all materials will be priced.
We are on target to complete this project to date.
In this meeting we discussed the current market prices and strengths/weaknesses of materials, and whether or not they should be used in the design. The stess analysist completed his analysis and handed the revised dimensions to the chief designer.
For the next meeting the designer will have completed the final CAD drawings and all materials will be priced.
We are on target to complete this project to date.
Wednesday, 17 March 2010
Mark Hawkins - Revision of Crane Feet Design
Whilst in discussion with other group members, improvements to the design of the feet of the crane were purposed. The original design, featured to the left of the image below, required the area of ground immediately beneath them to be level. It is highly unlikely that level ground could be located in an earthquake disaster zone and thus the feet were redesigned, as featured to the right of the image below, and were fitted with rounded rubber (or similar) stoppers at their base.
This new design allows the crane to be placed in a greater variety of locations and increases the ease at which the crane may be assembled, as the symmetry of the new feet mean that they do not require orientating. The image below shows a close up of the new design integrated into the crane structure.
Finally, below is the revised crane structure in its entirety. This design will require farther design alterations, and the next purposed change will be to replace the main solid square beam with an "I" beam. This will increase strength whilst decreasing overal weight. The altered design incorporating this change will be produced, along with any other recomended changes, once the stress analysis has been completed.
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