12 Replies Latest reply on May 30, 2014 6:52 PM by Jerry Steiger

    Help with assembly design

    Slurped Berbelito

      Hello. I've to design a mechanism similar to the one that a dump truck uses. I'm a bit clueless about how to turn my sketch (I've the image) into an assembly. Here is the link to the sketch (SLDPRT) that I've done: https://mega.co.nz/#!3oRj3axB!9bi95ieEnAmpNVBML0Ud2FuapOgRDJCNUorhdVzgBmA . Can anyone help me? (The SLDPRT is also uploaded in this post).


      Thank you very much.

        • Re: Help with assembly design
          J. Mather

          I do not see any sketches or attempts to model the geometry in the *.sldprt file that you attached here.

           

          Have you gone through the Help>Tutorials?

          Have you completed a class on using SolidWorks?

          How much training and experience do you have with SolidWorks?

           

          I didn't go to the link you posted - do you have any dimensions to use to scale the image?

            • Re: Help with assembly design
              Slurped Berbelito

              In the file that I attached there is the sketch (jpg file that I upload in this message as well) and a few lines that represent the bars. The problem is that from that I'm not able to see how to turn this image into separate pieces to build an assembly, and neither the measures nor the articulations.

               

              Thank you very much.Screen Shot 2014-05-27 at 19.33.47.png

            • Re: Help with assembly design
              Shawn Pantzke

              Hello Slurped,

               

              The first thing that you must do if you are to model this as an assembly is to model all of the parts individually. It looks to me as though there will be a number of parts that go into this assembly. Each of these parts should be its own part file (.sldprt) after creating the parts, place them into an assembly (.sldasm) and constrain them in a fashion that will allow the mechanism to move as it is designed to.

               

              This is not as easy as replicating the two images that you have attached in a sketch if a single part file. If that is what you would like to do there are other softwares out there designed for 2-D drafting like DraftSight.

               

              SLP

                • Re: Help with assembly design
                  Slurped Berbelito

                  Yes, yes. I know how to create an assembly on Solidworks, and I've done many of them. It's just that they are way easier than this one and I'm in trouble trying to find a solution to articulate this one, from the measures to the building of the separate pieces...

                   

                  I was asking for some help related to the way of finding this measures or the best way to reproduce this precise mecanism into SolidWorks.

                   

                  Thank you.

                    • Re: Help with assembly design
                      Keith Parker

                      You have shown two images of a railway truck that has a tipping mechanism and you say you cannot get measurements of it.  First - what is the guage (distance between rails) of the track that this truck is sitting on? If you know that, you have the scale of those drawings and you can create the parts & assembly from that single measurement.  Obviously you don't know the length of the truck but it seems as if the tipping mechanism is your area of interest, no the size of the truck.  All the part lengths and where they pivot can be determined from the left-hand image so using that image in a layout-type sketch should give you your mechanism.

                        • Re: Help with assembly design
                          Slurped Berbelito

                          Keith Parker wrote:

                           

                          You have shown two images of a railway truck that has a tipping mechanism and you say you cannot get measurements of it.  First - what is the guage (distance between rails) of the track that this truck is sitting on? If you know that, you have the scale of those drawings and you can create the parts & assembly from that single measurement.  Obviously you don't know the length of the truck but it seems as if the tipping mechanism is your area of interest, no the size of the truck.  All the part lengths and where they pivot can be determined from the left-hand image so using that image in a layout-type sketch should give you your mechanism.

                          Okay, I'll try to scale it and create the parts separately. Now, the big trouble is to create a mechanism that does that. I mean, it "rotates" by this pivot by the movement of the hydraulic cylinder placed at the left of the drawing. And then, the "door" on the right opens. Do you have any idea of how to create this (I'm pretty sure that it's easy) mechanism or do you know any example assembly to consider as a guide?

                           

                          Thank you very much.

                        • Re: Help with assembly design
                          J. Mather

                          Slurped Berbelito wrote:
                          I know how to create an assembly on Solidworks, .....


                          I was asking for some help related to the way of finding this measures ....

                          I doubt that pictorial image is very precise or to scale.

                          Do you have a picture of an actual real world assembly?

                           

                          The great thing about SolidWorks is that it is parametric.

                          So if you know how to create an assembly in SolidWorks - simply start modeling parts to approximate sizes.

                          Place the parts in assembly and adjust the parameters till the assembly works as expected.

                            • Re: Help with assembly design
                              Slurped Berbelito

                              J. Mather wrote:

                               

                              Slurped Berbelito wrote:
                              I know how to create an assembly on Solidworks, .....


                              I was asking for some help related to the way of finding this measures ....

                              I doubt that pictorial image is very precise or to scale.

                              Do you have a picture of an actual real world assembly?

                               

                              The great thing about SolidWorks is that it is parametric.

                              So if you know how to create an assembly in SolidWorks - simply start modeling parts to approximate sizes.

                              Place the parts in assembly and adjust the parameters till the assembly works as expected.

                              Yes. It's similar to this one: Dump_Truck_Insurance_1.jpg. the hydraulic cylinder goes up and then the right door opens. The difference is just that in the one I'm planning to do there is a pivot in the middle. Do you have any idea of how to create this (simple, I know...) mechanism? I'm stuck .

                               

                               

                              Thank you very much.

                                • Re: Help with assembly design
                                  J. Mather

                                  I know how it works.

                                  The image of the mechanism of the real truck you attached does not match the pictorial image mechanism.

                                  Not really even close to the same mechanism.

                                   

                                  How much experience do you have creating moving mechanism assemblies using SolidWorks?

                                  Do you have enough experience that you could model the easier mechanism from your second picture (the one of the real truck)?

                                    • Re: Help with assembly design
                                      Slurped Berbelito

                                      I've started this course... I'm just a begginer, but that is a task that I have to do and I'm not able to even sketch the mechanism. It's just too difficult for me and I don't know how to create the assembly to make it work as the image of the task suggests.

                                        • Re: Help with assembly design
                                          J. Mather

                                          I recommend that you first go through the Help>Tutorials

                                           

                                          Then I recommend that you start with mechanisms of less complexity.

                                          Do you have access to a library with books that have dimensioned mechanisms?

                                          Can you do a simple piston and cylinder lifting a pivoting box (simiar to your second image)?

                                          Give it a try and attach your assembly here as you run into any difficulties.

                                          • Re: Help with assembly design
                                            Jerry Steiger

                                            Slurped,

                                             

                                            Think of it as several simpler mechanisms that are tied together and imagine how the parts move as the cylinder extends. Pivot points G, N, F and C are fixed in position on the box. As the cylinder extends points on the box on the left side of the axis A move up and to the right while points on the right side move down and to the left. As G and N move to the right, they force H and M to move to the right. The fixed pivot at K forces H and L to move up. That forces the upper part of the gate to move up and the link between L and M forces the latch for the lower part of the gate to move up, unlatching the lower part of the gate. It looks like the positioning of E (fixed), F(on the box), C (on the lower gate) and D (on the link between E and D) keeps D moving only slightly so that the link between C and D pulls the lower gate open as C drops down. The trick is getting the postioning right so that the latch on the link between N and M pulls out before the lower gate starts to move significantly.

                                             

                                            Jerry S.