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  • Wheel Loader Design

    I am intrigued by front loader geometry, and wanting to rebuild my plastic toy one with metal parts and hydraulic operation, been taking a more serious look. I’ve found the linkages cad program to be a lot of fun to play with, and took a random drawing of a wheel loader to recreate the mechanism.


    So my question is this... Are wheel loaders designed so the bucket does not change in tilt with the arms raising? If I change the anchor point of the dump cylinder, I can get it so it barely changes with tilt. The drawing I used, I fear is more artistic than engineered to function properly. However, on the other hand, if real wheel loaders are supposed to tilt slightly back as they are raised, then the drawing is correct.


    Sent from my iPhone using Tapatalk Pro

  • #2
    I certainly can't speak for every type of machine and their individual types of linkage systems. But yes all of the Cat, John Deere, Volvo and Terex loaders that I have operated all maintain bucket position irrespective of lift height. Doing otherwise would be a real pain in the keester for the operator.

    Have a look at the bucket remaining stationary on this loader after the operator finishes curling the bucket inward in order to scoop in a bucket full of material. Once the bucket is full it does not move while it is raised. The bucket always remains in the position it was left in regardless of boom height or bucket position.

    First half of this video shows the lack of movement you are looking for.
    Home, down in the valley behind the Red Angus
    Bad Decisions Make Good Stories

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    • #3
      Most loaders stay at the same angle. My 555 back hoe loader stays until the last few degrees of swing then it tips down slightly. I have operated other loaders that do the same.
      Then you get into underground mucking machine loaders and they are completely different. Most can not dump if the bucket is raised too far. They use an ejector system to push the muck out of the bucket into a truck. Has to do with keeping the roof of the tunnel at a reasonable height.

      And I do remember some loaders that would spill some material over the back if raised to the limit. Skid steers come to mind.
      Last edited by 1-800miner; 04-16-2018, 10:06 PM.

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      • #4
        Unless I am mistaken, the bucket angle remaining constant during lift is achieved by the hydraulics, not the positioning of the linkage.
        “I know lots of people who are educated far beyond their intelligence”

        Lewis Grizzard

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        • #5
          There are 2, the parallelogram type (eg case 1845c) can deal with forks, the rhombic type tip down on lift, though load level valve can keep the nose up.
          The 1845c looks like a draughting machine from the side
          Mark

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          • #6
            Well, going based off that side view drawing, it is completely buggered. When I get back home, I will measure the toy loader and see how good of a job they did. Being that it’s German made, wouldn’t surprise me in the slightest if they designed that into a toy.

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            • #7
              Originally posted by Dave C View Post
              Unless I am mistaken, the bucket angle remaining constant during lift is achieved by the hydraulics, not the positioning of the linkage.
              Even though I have cycled that bucket literally thousands of times over the years, I'll have to admit it being several years since I was in the saddle. However having said that I must also admit to not having witnessed any movement in the bucket tilt cylinder/cylinders when raising or lowering the main boom arms. So if memory serves me right I'll respectfully have to disagree.

              Have a look at the video in the link below. While the lift cylinders arms raising the maim lift arms the bucket remains level, I cannot discern any movement in the bucket tilt cylinder as the arms are being raised.


              https://youtu.be/lmdamCV23EM?t=115
              Home, down in the valley behind the Red Angus
              Bad Decisions Make Good Stories

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              • #8
                Originally posted by Dave C View Post
                Unless I am mistaken, the bucket angle remaining constant during lift is achieved by the hydraulics, not the positioning of the linkage.

                Originally posted by Willy View Post
                Even though I have cycled that bucket literally thousands of times over the years, I'll have to admit it being several years since I was in the saddle. However having said that I must also admit to not having witnessed any movement in the bucket tilt cylinder/cylinders when raising or lowering the main boom arms. So if memory serves me right I'll respectfully have to disagree.

                Have a look at the video in the link below. While the lift cylinders arms raising the maim lift arms the bucket remains level, I cannot discern any movement in the bucket tilt cylinder as the arms are being raised.


                https://youtu.be/lmdamCV23EM?t=115
                You both are correct here. The vast majority of industrial wheel loaders are designed with a self leveling loader that relies on the location of pivot points to achieve that feature. However, there are some tractor/loader/backhoes that have a linkage connected to the loader hydraulic control valve that provides a self leveling feature. I'm thinking specifically of a Deere model a ran some years ago. As you lowered the loader via the single stick control the lever was pulled sideways to rotate the bucket, keeping it level. The feature could be overridden by simply moving the lever as needed.

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                • #9
                  I think what you are referring to is an automatic "return to home" feature that uses a proximity sensor to monitor the bucket's tilt cylinder position. When the bucket tilt cylinder reaches the level position it automatically stops the tilt cylinder.

                  This comes in handy when you've just dumped the bucket and are backing away from a truck for instance and lowering the main lift arms in order to position your machine into the pile for the next scoop. It saves a lot of time in that you just hit the bucket tilt lever after the dump and it stops exactly where you need it. This allows you to focus on safely backing away and into the pile for the next round. All you need to do is watch where you're going and lower the boom. One less critical thing to deal with and always consistent. Like you say it can be overridden if need be.

                  However it is the linkage that keeps the bucket level, or more accurately, in the position it was left in as the main lift arms are raised or lowered.
                  Home, down in the valley behind the Red Angus
                  Bad Decisions Make Good Stories

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                  • #10
                    It started with self luffing cranes. Wouldn't be surprised if DaVinci had a design for that.

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                    • #11
                      As a design engineer for John Deere 4WD Loaders (with experience designing backhoes as well), I am intrigued by this thread...interesting.

                      Both Caterpillar and Deere (Most major OEM's actually) have patents related to this. I will do a google search to see if I can share a link. Beyond that, I really enjoy working for Deere, so I won't say much more.
                      Last edited by Ggerg1186; 04-18-2018, 02:49 PM.
                      If the women don't find ya handsome, they should at least find ya handy

                      https://www.facebook.com/WDHSTechClub

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                      • #12
                        An interesting thread it is, and it has led me to reflect on the years when operating a wheel loader was part of my daily job or my daily job. Most were bucket machines but on many occasions the loader was the basis of a tool carrier with different priorities and challenges.

                        Some of the machines used differing, and often proprietary versions of the popular Z-bar linkage while others were strictly a parallel-lift configuration. There are also hybrid designs out there that share advantages of both design configurations.

                        But it is interesting to note that a slight roll back as that noted by the OP is common in basic Z-bar linkages system as shown in his drawing. It must have been very slight on the units that I have operated or my attention was always focused elsewhere as it simply wasn't an issue.
                        Probably too focused on the job at hand to dwell on design intricacies. Whatever, I never did any unintentional damage with bucket or tool carriers so my focus was justified.

                        Interesting link below discussing the pros and cons of various wheel loader linkage designs.

                        https://www.forconstructionpros.com/...-choose-wisely
                        Last edited by Willy; 04-18-2018, 09:02 PM. Reason: grammitical error
                        Home, down in the valley behind the Red Angus
                        Bad Decisions Make Good Stories

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