User Tag List

Page 2 of 3 FirstFirst 1 2 3 LastLast
Results 18 to 34 of 40
  1. #18
    Regular Member
    Join Date
    Sep 2003
    Location
    Toronto & Vancouver, Canada
    Posts
    681
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)

    Default

    one other thing wrong about your attached picture is that the racket is improperly mounted on the throat end.

    the black hold downs should be above the red internal supports.

  2. #19
    Regular Member
    Join Date
    Aug 2012
    Location
    Netherlands
    Posts
    18
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Default

    The image was sent today by stringway... i heard they advise a new way of mounting and this is the one send by Mr Timmer this afternoon. So i guess they changed it. Saw this picture before by Mr timmer under the name stringtechno

  3. #20
    Regular Member
    Join Date
    Apr 2007
    Location
    Netherlands
    Posts
    202
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Default Direct and indirect racquet support

    Hi guys, interesting discussion about the support system.
    I
    would like to add some information to this discussion:

    When we designed our racquet support we made a computer program to calculate the stress in the racquet material for different kind of racquet supports.

    Our 5 point direct (inside) system is the result of this development.

    Many people think that it is important to minimize the deformation of the racquet during stringing but this is not true (while it may sound very logic).

    A racquet does not break because the deformation is it too high it brakes because the stress (force per square millimeter) is too high in any place.

    The graph shows the stress in a racquet for different racquet supports.

    [IMG]http://imageshack.us/a/img189/2774/racquetstress.jpg[/IMG]



    This graph shows:
    - The minimum stress occurs with a 3 point inside system.
    - The stress goes up with an indirect (outside system) when you get closer to 3 and 9 o’clock.
    Therefore it is dangerous to string a badminton racquet with the supports too far away from the head.

    From this development we learned:

    - That the systems have to be divided in direct and indirect systems.

    [IMG]http://imageshack.us/a/img27/9536/direktindirekt.jpg[/IMG]



    - The stress in the racquet and the change of breaking is lower with a direct system.
    - With direct systems it does not make much difference for the racquet if we bottom up or top down.
    - That outside support CAUSE extra stress in the racquet and raise the change of cracks.

    The stringway/laserfibre will force you to go top to bottom for the crosses if you care about minimizing tension loss.
    I would like to know why because we advise to go bottom up.

    Also love the laserfibre! too bad you couldnt use the fixed clamps for the crosses....that's terrible! it is worth thinking about a upgrade in the future indeed.
    I would like to know why this is, our tournament stringers use the fixed clamps for all strings.

    Also i heard that laserfibre where imitations of string????? i thought that technifibre made the machines for technifibre. The store claimed that stringway did not prolonque their pattent and then some companies tried to copy. I found that hard to believe.
    We made the machines for Laserfibre. Our tensionhead was patented in 1983 so that patent is not valid anymore and Eagnas copied our tensioner in 2010.

    We do advise to support badminton racquets as shown on the picture above so that the wider throatside of the racquet is supported by 3 supports.

    There is a very simple solution when the last cross can not be clamped with a fixed clamp:
    - Skip the cross before the last one and enter the last one first.
    - Then enter the one before last and pull “knot tension” on both.
    - Clamp the string before the last one.

  4. #21
    Administrator kwun's Avatar
    Join Date
    Apr 2002
    Location
    Santa Clara, California, United States
    Posts
    35,915
    Mentioned
    52 Post(s)
    Tagged
    2 Thread(s)

    Default

    in the graph.

    for the 3 point inside and 3 point outside support cases, why is the stress highest at position 0 when there is a direct point of support right at position 0?

  5. #22
    Regular Member
    Join Date
    Mar 2011
    Location
    Montreal, Canada
    Posts
    895
    Mentioned
    16 Post(s)
    Tagged
    0 Thread(s)

    Default

    Many people think that it is important to minimize the deformation of the racquet during stringing but this is not true (while it may sound very logic).
    While your simulations seem good and all, it is a fact that if you don't try to prevent racket deformation during stringing (at higher tensions), the racket WILL break. For instance, if you put your side supports at the 10/2 position and string at 30 lbs, the racket has a very high chance of cracking at the 3/9 position. If the supports are closer to the 3/9 position, it has much lesser chance of breaking.

    The only reason I can see that your system would be safe is that the top and bottom supports are so strong that they prevent/minimize the deformation of the racket while stringing the mains, which still goes against what you said :\

  6. #23
    Regular Member
    Join Date
    Sep 2003
    Location
    Toronto & Vancouver, Canada
    Posts
    681
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)

    Default

    The stringway/laserfibre will force you to go top to bottom for the crosses if you care about minimizing tension loss.
    Quote Originally Posted by stringtechno View Post
    I would like to know why because we advise to go bottom up.
    My reply: Please see my replies previously in this thread. hold down clamps are physically obstructing me from clamping (from above) the top 2 cross strings of a badminton racket (for fly clamps especially). Specifically they will not be aligned straight...it will be crooked.
    I cannot clamp from below with a fly clamp because the black mounting plate is obstructing clamp from getting at the first cross. Therefore a fixed clamp cannot get to the first cross. The only option is to pull the top two crosses and clamp. There's a separate thread about pulling 2 crosses at once.

    -----

    Also love the laserfibre! too bad you couldnt use the fixed clamps for the crosses....that's terrible! it is worth thinking about a upgrade in the future indeed.
    Quote Originally Posted by stringtechno View Post
    I would like to know why this is, our tournament stringers use the fixed clamps for all strings.
    I talked about it back in 2007-2008 (i had both sets of fixed clamps - tennis and squash/badminton) here:
    http://www.badmintoncentral.com/foru...834#post814834
    talk about the clamp design here
    http://www.badmintoncentral.com/foru...947#post652947
    pics are here:
    http://www.badmintoncentral.com/foru...783#post803783
    the gaps between teeth were too big..so it would either squish or push 2 adjacent mains.

    Matsumoto...if you have more questions u should read through the other laserfibre/stringway threads or contact stringtechno directly.

    A lot of this stuff has been discussed over and over for many years.
    I hope these links illustrate everything.

    As stringtechno said...regardless of the label on the machine..it was manufactured by stringway and the parts come directly from them. It's the same machine. NO difference whatsoever.

  7. #24
    Regular Member
    Join Date
    Sep 2003
    Location
    Toronto & Vancouver, Canada
    Posts
    681
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)

    Default

    Let's shift the focus back on the merits of the machine:

    1) it can string at high tension (regardless of what type of support system it uses...the merits of each one were discussed in another thread here: http://www.badmintoncentral.com/foru...ght=laserfibre. continue it there)
    2) it's constant pull
    3) low maintenance
    4) drop weight but does not require weight to be level
    5) can string all rackets (tennis, squash, racketball, badminton)
    6) has option for fixed clamps

    Limitations (my opinion):
    1) cannot upgrade to electronic easily (WISE) or unless you switch to a full electronic (EM-450)
    2) fixed clamps for badminton large gap between teeth such that it's only good for mains and not for crosses (use fly clamps instead)
    3) top down stringing for crosses recommended because top most cross cannot be clamped as close to frame without being misaligned due to contact with hold down clamp, or mounting plate.

    Like I said before. Terrific machine for 6 years. My needs changed warranting me to get a new machine.

    This will be the last i ever comment about this machine.
    People...use the search button and reach your own conclusions. A lot of what i said has been said before.
    Last edited by DarthHowie; 04-16-2013 at 02:46 PM.

  8. #25
    Regular Member
    Join Date
    Apr 2007
    Location
    Netherlands
    Posts
    202
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Default

    Excuse me for entering the last post twice, can you remove or empty it Kwun?

    This will be the last i ever comment about this machine.
    I think, that the background information about a design of a machine or system deals very much with the machine.

    In the stringing industry many things are produced based on what stringers experience and not based on calculations or theories, like real developments.
    The outside supports “were born” in this way, stringers saw that the racquet got wider and ht industry “found out” the external supports to prevent that.
    The first thing that was supplied was a bracket that was fixed between 3 and 9 o’clock. This bracket disappeared faster than it came because the racquets broke on the machine.

    Our philosophy is to prevent the racquet from getting wider by preventing it from the getting shorter.
    The worst moment for a racquet occurs when all main strings are tensionedy a DIRECT SUPPORT SYSTEM works directly against the forces of the mains.

    If the racquet does not get shorter it does not get wider either.



    for the 3 point inside and 3 point outside support cases, why is the stress highest at position 0 when there is a direct point of support right at position 0?


    The stress which cracks the racquet is the bending stress and this stress is always maximum at the position of the supports.

    On the Indirect system at 12 o’clock the racquet is actually bended around the central support, therefore it is much better to use a very wide central supports.

    The 3 wide supports on the SW machine at the head side support the racquet against the forces of the main strings DIRECTLY.

    You can also turn the question about the outside supports around:

    Why do you never hear of broken racquet on simple inside support systems like the ones from Prince or Ektelon?

    The answer is simple: The outside supports introduce bending stress in the racquet that is not there at all without the supports.
    I will illustrate this with a picture in the next post.

    Most machine we sell to badminton stringers at the moment are supplied with Yonex flying clamps, these are very good clamps and the price of the machine is much lower than with fixed clamps.
    Last edited by stringtechno; 04-17-2013 at 11:07 AM.

  9. #26
    Regular Member
    Join Date
    Apr 2007
    Location
    Netherlands
    Posts
    202
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Default

    This picture explains more about direct compared to indirect support and the stress that is caused by the indirect support




    The support in C is a direct support and in A is an indirect support.

    Conclusion can be:
    - There is no stress between point A and C without the support in A.
    - Supporting the beam in C were the Force works causes no stress at all between A and C

  10. #27
    Regular Member
    Join Date
    Mar 2011
    Location
    Montreal, Canada
    Posts
    895
    Mentioned
    16 Post(s)
    Tagged
    0 Thread(s)

    Default

    Our philosophy is to prevent the racquet from getting wider by preventing it from the getting shorter.
    The worst moment for a racquet occurs when all main strings are tensionedy a DIRECT SUPPORT SYSTEM works directly against the forces of the mains.

    If the racquet does not get shorter it does not get wider either.
    Now that I can agree with.

    It's different than "minimizing deformation is not important", because by preventing the racket to get shorter, you minimize deformation :P

  11. #28
    Regular Member
    Join Date
    Apr 2007
    Location
    Netherlands
    Posts
    202
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Default

    You are right I put that wrong, of course you have to prevent deformation of the racquet, but in the main direction not in the “indirect” direction.

    I actually meant, that not the deformation but the stress in the material is the danger for the racquet.

    Compared with the beam: The deformation in point A is big but there is no stress at all between A and C.

  12. #29
    Regular Member
    Join Date
    Sep 2005
    Location
    Holland
    Posts
    3,966
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default

    Why do I feel as if I've read this entire discussion before?

    I have a riddle for you, seeing as you're quite obviously an engineer. Why does every motor manufacturer only use two bearing on each axle instead of 3? (Seeing as your so very much in favor of 3 supports as per post #26)

  13. #30
    Regular Member
    Join Date
    Apr 2007
    Location
    Netherlands
    Posts
    202
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Default

    Why do I feel as if I've read this entire discussion before?
    It has been on tenniswarehouse also, but it comes back every now and then because there are many misunderstanding about the way a racquet support works.


    I have a riddle for you, seeing as you're quite obviously an engineer.
    Why does every motor manufacturer only use two bearing on each axle instead of 3? (Seeing as your so very much in favor of 3 supports as per post #26)
    This is all a matter of the maximum load, as you probably know crank- and cam shafts of cars have much more bearings than 2.

    For a racquet support counts the more supports on the inside the lower the stress in the racquet.



    If there would be an inside support at every position of a main string the racquet would not feel anything at all.
    Because this is practically impossible we choose for 3 wide supports, one of them is adjustable so that every shape can be supported.


  14. #31
    Regular Member
    Join Date
    Sep 2005
    Location
    Holland
    Posts
    3,966
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default

    Okay, well thank you again for the copy paste, I'll just proceed with what I wanted to say.
    The idea supporting 1 beam with 3 supports is not used in these simple mechanical systems because of the risk of getting a moment-force on your middle support.

    If you can place a support directly under the load the system is amazing, but if you place a load slightly in between supports then the statics of the system change. Now the beam in between the other supports even wants to go up. Imaging the stress on that part of the beam if there's a load on there as well.

    This is why I object to you're simplief scematic, you make it too easy on yourself
    Attached Images Attached Images  

  15. #32
    Regular Member
    Join Date
    Apr 2007
    Location
    Netherlands
    Posts
    202
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Default

    This is why I object to you're simplief scematic, you make it too easy on yourself
    The example with the beam is only to demonstrate that a support at the end (were the deformation is maximum) introduces bending stress where there is no stress at all without that support.

    If you compare the racquet with the beam you have to add a number of forces on each side of the support in C.

    Therefore it is very important to choose the right position of the support “in between” all these strings.

    The graph shows that the stress in the racquet is minimum when the distance between the supports is 52 mm.
    In this calculation we took an oversize racquet because that is the worst case that can occur.

  16. #33
    Regular Member Mark A's Avatar
    Join Date
    Sep 2005
    Location
    St Helens, UK
    Posts
    4,079
    Mentioned
    14 Post(s)
    Tagged
    0 Thread(s)

    Default

    Quote Originally Posted by stringtechno View Post
    For 6-point outside support (as most of us have), 175 mm is actually quite far down the racket - roughly at the level of the fifth hole after the last main on a standard pattern. That's pretty much at 3 o'clock.

  17. #34
    Regular Member
    Join Date
    Apr 2007
    Location
    Netherlands
    Posts
    202
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Default

    The calculation, that is shown in the graph is made for the most difficult situation which are oversize tennis racquets at high tensions.
    So 175 mm counts for that situation.

    The smaller the racquet the smaller the distance.

    At the same time this is the danger, when badminton racquets are strung on a support that is actually meant for tennis, and is not adjustable. In that case the outside support come too close to 3 and 9 o’clock and the stress in the racquet will be very long.

    Iow: The longer the “lever” of the forces of the outside supports the higher the bending force and the stress in the racquet.

Page 2 of 3 FirstFirst 1 2 3 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •