Mounting bracket - your feedback - Page 1
Forum section: electronics / general

author: Martin F
author_rank: Regular Contributor
timestamp: November 25, 2019, 08:10:41 am
content: Hi all,We're in the process of designing a mounting bracket for use with our data logger - for an online view, see below:https://bit.ly/2OHQfWIUse case: The data logger is to be installed in various locations - and take up as little space as possible. Installation use cases include against metal plates in e.g. vehicles (trucks, forklifts, cars), production machinery, regular walls etc. It may also be that some users would want to install it onto e.g. round pipes (using strips) or other irregular surfaces.The data logger itself will be secured using strips that go across the top of the device, using the 4 round holes in the bended part of the bracket.The bracket should be small, low-cost and simple to manufacture, while being flexible enough to support most of the use cases suggested. Further, it should support usage on vibration-heavy surfaces. The current design is a very crude 1st cut.It would be great to get your feedback/inputs on below areas:1) Overall 1st cut design vs. use case - any thoughts?2) What kind of screws would you consider using for e.g. mounting this against a vehicle metal plate?3) What kind of holes & hole positions should the backside have for such screws?4) If the screws have large heads, we're concerned that these will press against the backside of our device, causing more strain. To resolve this we considered adding e.g. large rubber feet on the backside of the device to put space between this and the heads - but maybe you have alternative suggestions?5) If we are to add strips as an option for mounting the bracket onto e.g. pipes, what kind of holes/design would you recommend for this?6) What kind of material and thickness would you recommend for this type of mounting bracket?Thanks for your inputs!

author: nali
author_rank: Frequent Contributor
timestamp: November 25, 2019, 09:38:50 am
content: I guess the first thing to ask is who will do the fitting? If it's your own engineers that's not so bad but if it will be a customer fit then you'll need to cater for all types & sizes of screw.I've done this before, but I opted for almost the reverse of yours making the bracket a saddle clamp / cover. So the installer places the device on the surface, then the cover over the device and screws it down. That way the bracket provides a bit of extra protection (you can extend it a bit to cover the connectors too).

author: Martin F
author_rank: Regular Contributor
timestamp: November 25, 2019, 09:54:10 am
content: Hi Nali, thanks for the feedback.This will be installed by the end user, so ideally yes we'd cater to different types of screws - hence we're also looking for what might be the best compromise on holes to cater to the most typical screw sizes that would be used for this type of mounting.Our motivation for using this shape rather than a saddle was to have a back-side plate to allow for optional vibration reduction - either in the form of vibration screws or in the form of e.g. foam in between the backside of the device and the mounting bracket. If a saddle solution was to be used, we would think it would require at least to still have a backside end plate, in which case the bracket also becomes a bit more complex to manufacture we believe.Martin

author: sokoloff
author_rank: Super Contributor
timestamp: November 25, 2019, 11:15:54 am
content: Plan for countersunk screw heads to avoid the large head issue.I’d size them with a #16 drill to fit M4 or 8-32 screws (both very common sizes).

author: edy
author_rank: Super Contributor
timestamp: November 26, 2019, 07:32:13 pm
content: 3M foam tape... The stuff is strong enough to hang hooks for towels, bath robes, etc. A couple of strips of this stuff along the underside of your device will provide for both vibration "padding" and well secure your device to the vehicle surface. It avoids you needing to make a mounting plate altogether. No screwing needed or worrying about head size, hold sizes. You can supply the end-user with a bunch of strips pre-cut, and avoids them having to drill holes in their vehicle. Way easier if you ask me. I wouldn't want to ruin the inside of my car.Check here:https://www.3m.com/3M/en_US/company-us/all-3m-products/~/All-3M-Products/Adhesives-Tapes/Industrial-Adhesives-and-Tapes/Double-Sided-Bonding-Tapes/Foam-Tapes/?N=5002385+8710676+8710815+8710960+8711017+8713621+3294857497&rt=r3If you've ever bought these hook/tape kits (see photo below), you will know how strong they can be. With a large flat surface on the back of your data-logger case, it will grab tightly. The hook tape has a tab that sticks out... so when you want to unstick, you just pull it out sideways (along the direction of your wall) and it will debond without ripping your drywall. Otherwise the stuff stays on strong:This stuff will work great for any flat surface, metal and so on. For irregular surfaces you will be using ZIP-ties, in which case I would just 3M tape a flat plate with holes to your datalogger (since it has no holes in the datalogger casing itself) so you can run ZIP-ties through.

author: Muttley Snickers
author_rank: Unknown
timestamp: November 27, 2019, 10:33:16 am
content: I wouldn't be using adhesives unless the mounting surface was completely clean and free from any oils or grease. My preference would be for metal self drilling screws with large shallow heads and if the mounting base incorporated channels then the screw heads would be below the underside of the module.Also, in the third image the base plate wings aren't doing very much so if they were extended and had the same radius as the module then they could be utilised to hold the module whilst final fixings or ties are applied. To clarify, the module could easily clip into the base plate if those wings were rolled inwards.

author: ebastler
author_rank: Super Contributor
timestamp: November 27, 2019, 03:05:03 pm
content: When you say "strips", do you mean cable ties? It will be a bit of a fumble to route these through the small holes; and the sharp edges of the mounting brackets may cause the ties to break over time.Speaking of sharp edges, you really should round at least the corners of those lips which point upwards. Users will hurt their hands otherwise, either during installation or later when servicing some nearby components.Finally -- does the "lip" of the bracket on the side with the Sub-D jacks leave enough room for the body/housing of the plugs you want to insert there? Seems tight.

author: Martin F
author_rank: Regular Contributor
timestamp: November 27, 2019, 03:30:52 pm
content: Thanks all for the great inputs!I'll share an updated STEP later this week where we integrate some of your comments, will keep you posted.

author: Martin F
author_rank: Regular Contributor
timestamp: November 27, 2019, 03:38:00 pm
content: One additional comment:- We'll most likely make the edges so that they are 90 degrees- Further, we will probably add some foam tape as padding - ideally to reduce vibration and avoid metal scraping against metal.If some of you have good suggestions for low cost foam tape that can server as padding, that would be interesting. We're thinking something that can perhaps be found in pre-cut lengths ala 4 cm x 0.5 cm or similar with a reasonable thickness. The idea would be to find something that would be possible to add on the sides as well as on the backside. This way it may be possible to avoid the counter-sunk holes for screws (which would reduce thickness and cost significantly) as the device would be "lifted" by the padding to be above the screw heads.Any suggestions are welcome.Martin

author: Domagoj T
author_rank: Frequent Contributor
timestamp: November 27, 2019, 10:36:08 pm
content: A few M4 screws would hold this no problem. Perhaps a bit of thread lock to prevent loosening from vibration, however, you expect customer to drill the holes and tap the thread themselves? Sure that could work, depending on your target audience, but tapping into the who knows what alloy plate of a forklift could prove to be troublesome, not to mention the potential of damaging whatever is on the other side. On the other hand, using a nut on the other side would mean that there is no need to tap the thread, but it may be impractical to reach the back to install the nut, depending on the machine.I wouldn't discount industrial adhesives. There are some real nice products out there.

author: edy
author_rank: Super Contributor
timestamp: November 28, 2019, 03:05:23 am
content: Quote from: Domagoj T on November 27, 2019, 10:36:08 pmDitto.... I am normally not a big fan of adhesives/tape, etc... but in some applications it is better to rely on it and have the occasional "debonding" and easily glue/tape it back than rely on customers to drill holes into their vehicular or instrument panels. I've got 3M taped hooks all over the bathroom and closet doors in my house and they hold a lot more weight than your device weighs. Yes we do get the occasional "debond" but it is far easier for me to restick a hook in 2 seconds than to damage my doors for eternity. If you don't use the tape, then some adhesive compounds or special tack might work. Go here and fill out the form where it says "ASK A 3M EXPERT"... I'm sure they have pre-cut options as well:https://www.3m.com/3M/en_US/bonding-and-assembly-us/double-sided-tape/Look, I even found this special-purpose tape and the description says it is used for data-loggers:https://www.tecnosoft.eu/en/products/11/162/adhesive-rubber-for-high-temperature-data-loggers-fixing/QuoteI also found a company that sells 3M adhesive "patches" here.. they call it "3M double-sided adhesive tape patch for automobile bracket driving recorder ETC waterproof, traceless and high temperature resistance":http://www.newbecca.com/product/551485756201And here...https://www.amazon.ca/Adhesive-Replacement-APPS2Car-Dashboard-Car-Mount-Adhesive/dp/B07PHK4MVYKnown as 3M VHB adhesive pads.

author: Shock
author_rank: Super Contributor
timestamp: November 28, 2019, 07:37:05 am
content: I would make a rectangular outer cage for it with enough space to add padding, add whatever holes and slots you need to. Or you could make it half cage by adding a plate or cross pieces to secure the device in place, or two halves that screw together. To support strapping to poles you can screw the cage onto a length of thin flat bar, you can buy this predrilled. It depends how well they want secure it but there are probably already products on the market to strap boxes to poles.

author: Martin F
author_rank: Regular Contributor
timestamp: November 28, 2019, 07:55:24 am
content: Hi Shock, the picture you added is very similar to the updated version we're putting together - can you let me know where you found this?Martin

author: coppercone2
author_rank: Super Contributor
timestamp: November 28, 2019, 08:15:38 am
content: consider the use of rivets and possibly add rivet holes, with how little people know about bolts it might be betterI don't know if you want to give the customer the option of custom bolt use, supply bolts and standardize to make it best against vibration. only offer support if done properly with rivets in rivet holes or proper speced bolts (its automotive!). not a consumer power strip. grade, torque and vibration retention system needs to be standardized (i.e. manual says either loctite or specific lock nut etc).bad mounts are a cause of rejection (i.e. look at post singars military radio evaluation). it needs to be controlled for liabilities sakethe other vehicular mount option you might want to explore/add is steel cutoff ties but only if tested, to make it simple you might consider stud inserts and just supply nuts (this is a more serious design if done right). you can also demand the customer check flatness and thickness of the mounting surface to some spec (perhaps with a strait edge).also, possibly sell a cheap template with it for drill holes, even if adhesive backed removable paper (silicone) that has hole punch predrill locations, obviously caution about deburring.for pipes, steel cutoff ties with proper tools and special backing plate. you probobly should sell a different stiffer bracket for pipe mount. this one is much more difficult.be very careful with adhesive and padding in automotive because its considered a harsh environment depending on where. materials quality and supply chain surveillance is vital here IMOand, wont that antenna com loose possibly?

author: Shock
author_rank: Super Contributor
timestamp: November 28, 2019, 08:42:55 am
content: Quote from: Martin F on November 28, 2019, 07:55:24 amIt's a 3.5" HDD mounting bracket image I modified a little to give you ideas.

author: coppercone2
author_rank: Super Contributor
timestamp: November 28, 2019, 08:45:31 am
content: you can also add anti rotation pins if you make a good template, but it would only work on flat surfaces and holes drilled/reamed by someone precise, and if the metal deforms underneath obviously the problem is you would need to bang the thing out.this would make the template mandatory, and it WILL piss people off because the template will be lost, particularly if relocated... then any pins you have on it will be ground off in short order\'is the bracket template on file?" evil engineering shitstuds you can at least kinda get around if you put ink on the bolts and press it on something, but precise hole location for a strengthening pin will cause rage. people would need to mill out pointed covers that go over the pins with precise centering to reverse engineer it...not sure if it would work, but for stabilizing the antenna you can supply a plastic heat deformable rod so you adjust the antenna, then bend the rod to the correct position, bond it and tie the antenna to the rod, but it will cause degradation.

author: Martin F
author_rank: Regular Contributor
timestamp: December 02, 2019, 09:45:45 am
content: Hi again,Just a quick update, we've made some changes to the bracket and you can check it out below.https://bit.ly/34FYwktThe bracket is designed so that the device is "locked in" via strips on the front. It can then be mounted on e.g. a vehicle surface/pillar with screws, 3M doublesided tape or strips. On the inside, the idea is to add foam to reduce vibration and avoid metal scraping.Any feedback is welcome,Martin

author: Shock
author_rank: Super Contributor
timestamp: December 02, 2019, 11:10:38 am
content: I would add 2 vertical and 2 horizontal simple holes centered between the sets of slots but closer to the edge, more options for easier strapping on narrower surfaces. The thickness looks good, ensure adequate clearance for the DE9.If that is an SD card slot you might want to cover it with the bracket or think about dust depending on the mounting orientation. I charge by the half hour, if you want to call it quits there.