Re: [PSES] 61010-1 Stability test, Para 7.4 Stability

[Richard Nute]

 

Hi Steve:

 

In studying other standards, some have specified toppling, such as exceeding 15 
degrees (IEC 62368-1, 4th ed., 8.6.5) or exceeding 10 degrees (IEC 62368-1, 2nd 
ed., 8.6.2.2).  On the other hand, IEC 60335, 4th ed., has no such stability 
requirement that I could find.  (By the way, the same requirement as in 1010 is 
in IEC 60950-1.)  

 

If a redesign is warranted, I suggest spring-mounting the mast such that a 
toppling force is not transmitted to the base.

 

Richard Nute

Bend, Oregon, USA

 

Ps:  It is clear that the requirement assumes a monolithic construction.  


-

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Re: [PSES] 61010-1 Stability test, Para 7.4 Stability

[Steve Brody]

Doug - comments are appreciated.
 
Unit is intended to be mobile, but only operational when off casters and 
leveled via the feet.
 
Ballast in the base is being considered by the MEs, and I did not complete the 
Section 17 RA yet so your comments are useful there.
 
Thanks.

> On 02/13/2024 12:10 PM EST Douglas Powell  wrote:
>  
>  
> HI Steve,
>  
> One thought that occurs to me. The method of test does not seem to mention if 
> it is intended for final installation or during the time when the unit is 
> mobile.  By your description, I assume you intend it to be non-mobile.  I did 
> this sort of topple test once before on a telescopic construction site light 
> tower. In that case, the topple test is unavoidable, but we had other 
> concerns about the tilt and then the release. The concern was about the unit 
> going over the center in the other direction after being released and whether 
> it would topple. The solution was to add more ballast in the battery 
> compartment below. 
>  
> In this case, I would try to get clarification on whether this test is 
> applicable to the operartional state and location only (castors up), and what 
> the level of expertise required for mobility? My assumption is it's 
> non-operational while mobile, if that even matters.  
>  
> Another possibility is to write up "conditions of use", in the user documents 
> and cover this concern under Section 17 Risk Assessment since it seems 
> possible that your concerns are not "fully addressed" in sections 6 thru 16, 
> 3rd edition. 
>  
> Best of luck, ~ Doug
>  
> 
> Douglas E Powell
> Laporte, Colorado, USA
> doug...@gmail.com mailto:doug...@gmail.com
> LinkedIn 
> https://streaklinks.com/B2gQNFh5uTDCaJcTcQbLipiI/https%3A%2F%2Fwww.linkedin.com%2Fin%2Fcoloradocomplianceguy%2F
>  
> (UTC-06:00, US-MDT)
>  
>  
>  
>  
>  
> ᐧ
> 
> On Mon, Feb 12, 2024 at 10:36 PM Steve Brody  mailto:sgbr...@comcast.net> wrote:
> 
> > Experts:
> >  
> > I need your opinions on the following.
> >  
> > I am having a 'discussion' with an NRTL on a product that I can't show you 
> > a picture of but here is a description:
> > * the base of the unit is 20" w x 26" l x 29" hf
> > * the base of the unit is mounted on caster/leveling feet devices that when 
> > positioned for use, the leveling feet are lowered and the casters come off 
> > the ground, and the leveling feet are sufficiently rated for more than 4x 
> > the load of each corner
> > * in the middle of the top of the base there is a robot mast for the Z 
> > axis, and it measures roughly 4" square and is 41" tall
> > * the whole product weighs 220 lbs
> > The stability requirements in 61010-1 are as follows, and I highlighted the 
> > text of interest:
> >  
> > Equipment and assemblies of equipment not secured to the building structure 
> > before operation shall be physically stable.
> >  
> > If means are provided to ensure that stability is maintained after the 
> > opening of drawers, etc. by an OPERATOR, either these means shall be 
> > automatic or there shall be a warning marking to apply the means.
> >  
> > Each castor and support foot shall be RATED to support a load of at least 4 
> > times its normal load, or the castors and support feet shall be tested 
> > according to d) and e), below.
> >  
> > Conformity is checked by inspection and by carrying out each of the 
> > following tests, if applicable, to ensure that the equipment will not 
> > overbalance. Containers contain the RATED amount of substance which 
> > provides the least favourable conditions of NORMAL USE. Castors are in 
> > their least favourable position of NORMAL USE. Doors, drawers, etc. are 
> > closed unless otherwise specified below.
> > 1.
> > 1. Equipment other than HAND-HELD EQUIPMENT is tilted in each direction to 
> > an angle of 10° from its normal
> > 2. Equipment which has both a height of 1 m or more and a mass of 25 kg or 
> > more, and all floor-standing equipment, has a force applied at its top, or 
> > at a height of 2 m if the equipment has a height of more than 2 The force 
> > is 250 N, or 20 % of the weight of the equipment, whichever is less, and is 
> > applied to all surfaces in directions which could cause the equipment to 
> > topple. Stabilizers used in NORMAL USE, and doors, drawers, etc., intended 
> > to be opened by an OPERATOR, are in their least favourable positions.
> > 3. Floor-standing equipment has a force of 800 N applied downwards at the 
> > point of maximum moment to:
> > + all horizontal working surfaces;
> > + other surfaces providing an obvious ledge and which are not more than 1 m 
> > above floor
> >  Doors, drawers, etc. are closed, except that those intended to be opened 
> > by an OPERATOR are in their least favourable positions.
> >  
> > When the force was applied at the top of the robot mast, it unit started to 
> > topple at 38 lbs, which is less than the required 44 lb force according to 
> > the standard.
> >  
> > The case I presented why this test 

Re: [PSES] 61010-1 Stability test, Para 7.4 Stability

[Douglas Powell]

HI Steve,

One thought that occurs to me. The method of test does not seem to mention
if it is intended for final installation or during the time when the unit
is mobile.  By your description, I assume you intend it to be non-mobile.
I did this sort of topple test once before on a telescopic
construction site light tower. In that case, the topple test is
unavoidable, but we had other concerns about the tilt and then the release.
The concern was about the unit going over the center in the other direction
after being released and whether it would topple. The solution was to add
more ballast in the battery compartment below.

In this case, I would try to get clarification on whether this test is
applicable to the operartional state and location only (castors up), and
what the level of expertise required for mobility? My assumption is it's
non-operational while mobile, if that even matters.

Another possibility is to write up "*conditions of use*", in the user
documents and cover this concern under Section 17 Risk Assessment since it
seems possible that your concerns are not "*fully addressed*" in sections 6
thru 16, 3rd edition.

Best of luck, ~ Doug


Douglas E Powell
Laporte, Colorado, USA
doug...@gmail.com
LinkedIn


(UTC-06:00, US-MDT)





ᐧ

On Mon, Feb 12, 2024 at 10:36 PM Steve Brody  wrote:

> Experts:
>
> I need your opinions on the following.
>
> I am having a 'discussion' with an NRTL on a product that I can't show you
> a picture of but here is a description:
>
>- the base of the unit is 20" w x 26" l x 29" hf
>- the base of the unit is mounted on caster/leveling feet devices that
>when positioned for use, the leveling feet are lowered and the casters come
>off the ground, and the leveling feet are sufficiently rated for more than
>4x the load of each corner
>- in the middle of the top of the base there is a robot mast for the Z
>axis, and it measures roughly 4" square and is 41" tall
>- the whole product weighs 220 lbs
>
> The stability requirements in 61010-1 are as follows, and I highlighted
> the text of interest:
>
> Equipment and assemblies of equipment not secured to the building
> structure before operation shall be physically stable.
>
> If means are provided to ensure that stability is maintained after the
> opening of drawers, etc. by an OPERATOR, either these means shall be
> automatic or there shall be a warning marking to apply the means.
>
> Each castor and support foot shall be RATED to support a load of at least
> 4 times its normal load, or the castors and support feet shall be tested
> according to d) and e), below.
>
> *Conformity* *is* *checked* *by* *inspection* *and* *by* *carrying* *out*
> *each* *of* *the* *following* *tests,* *if* *applicable**,* *to* *ensure*
> *that* *the* *equipment* *will* *not* *overbalance.* *Containers*
> *contain* *the* *RATED* *amount* *of* *substance* *which* *provides* *the*
> *least* *favourable* *conditions* *of* *NORMAL* *USE**.* *Castors* *are*
> *in* *their* *least* *favourable* *position* *of* *NORMAL* *USE**.*
> *Doors,* *drawers,* *etc.* *are* *closed* *unless* *otherwise* *specified*
> *below.*
>
>1.
>   1. *Equipment* *other* *than* *HAND**-**HELD* *EQUIPMENT* *is*
>   *tilted* *in* *each* *direction* *to* *an* *angle* *of* *10**°*
>   *from* *its* *normal*
>   2. *Equipment which has both **a height of 1 m or more and a mass
>   of 25 kg or more, and all floor-standing equipment, has a force applied 
> at
>   its top, or at a height of 2 m if the equipment has a height of more 
> than 2
>   The force is 250 N, or 20 % of the weight of the equipment, whichever is
>   less, and is applied to all surfaces in directions which could cause the
>   equipment to topple. Stabilizers used in **NORMAL* *USE**,* *and*
>   *doors,* *drawers,* *etc.,* *intended* *to* *be* *opened* *by* *an*
>   *OPERATOR**,* *are* *in* *their* *least* *favourable* *positions.*
>   3. *Floor-standing* *equipment* *has* *a force of 800 N applied
>   downwards at the point of maximum moment to:*
>  - *all* *horizontal** working* *surfaces;*
>  - *other* *surfaces* *providing* *an* *obvious* *ledge* *and*
>  *which* *are* *not* *more* *than* *1 m above floor *
>
>  *Doors,* *drawers,* *etc.* *are* *closed,* *except* *that* *those*
> *intended* *to* *be* *opened* *by* *an* *OPERATOR **are* *in* *their*
> *least* *favourable* *positions.*
>
> When the force was applied at the top of the robot mast, it unit started
> to topple at 38 lbs, which is less than the required 44 lb force according
> to the standard.
>
> The case I presented why this test was not applicable was:
>
>- because the robot mast is located in the center of of the unit, and
>not flush with the sides, that it did not represent the same situation as a
>bookcase, filing 

Re: [PSES] 61010-1 Stability test, Para 7.4 Stability

[Charlie Blackham]

My 2p / 2c

You’re presumably asking an NRTL to list your product so it can be a bit of a 
“their bat, their ball”, but I would ask them at what height are they applying 
the horizontal force as in my view it is unreasonable to do this above shoulder 
height, and even that is unrealistic for how people push things.

If I understand correctly, the top of the robot is 70” above the floor – that 
is a very high height to push anything.

SEMI-S8-1116 (2016)  states that 95th Percentile Male (US) standing shoulder 
height is 61.9 inches (citing Pheasant (1998), MIL-STD-1472D(1994) and SAE 
J833(1989)).

Best regards
Charlie

Charlie Blackham
Sulis Consultants Ltd
Tel: +44 (0)7946 624317
Web: https://sulisconsultants.com/
Registered in England and Wales, number 05466247

From: Steve Brody 
Sent: Tuesday, February 13, 2024 5:37 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] 61010-1 Stability test, Para 7.4 Stability

Experts:

I need your opinions on the following.

I am having a 'discussion' with an NRTL on a product that I can't show you a 
picture of but here is a description:

  *   the base of the unit is 20" w x 26" l x 29" hf
  *   the base of the unit is mounted on caster/leveling feet devices that when 
positioned for use, the leveling feet are lowered and the casters come off the 
ground, and the leveling feet are sufficiently rated for more than 4x the load 
of each corner
  *   in the middle of the top of the base there is a robot mast for the Z 
axis, and it measures roughly 4" square and is 41" tall
  *   the whole product weighs 220 lbs
The stability requirements in 61010-1 are as follows, and I highlighted the 
text of interest:

Equipment and assemblies of equipment not secured to the building structure 
before operation shall be physically stable.

If means are provided to ensure that stability is maintained after the opening 
of drawers, etc. by an OPERATOR, either these means shall be automatic or there 
shall be a warning marking to apply the means.

Each castor and support foot shall be RATED to support a load of at least 4 
times its normal load, or the castors and support feet shall be tested 
according to d) and e), below.

Conformity is checked by inspection and by carrying out each of the following 
tests, if applicable, to ensure that the equipment will not overbalance. 
Containers contain the RATED amount of substance which provides the least 
favourable conditions of NORMAL USE. Castors are in their least favourable 
position of NORMAL USE. Doors, drawers, etc. are closed unless otherwise 
specified below.

  1.

 *   Equipment other than HAND-HELD EQUIPMENT is tilted in each direction 
to an angle of 10° from its normal
 *   Equipment which has both a height of 1 m or more and a mass of 25 kg 
or more, and all floor-standing equipment, has a force applied at its top, or 
at a height of 2 m if the equipment has a height of more than 2 The force is 
250 N, or 20 % of the weight of the equipment, whichever is less, and is 
applied to all surfaces in directions which could cause the equipment to 
topple. Stabilizers used in NORMAL USE, and doors, drawers, etc., intended to 
be opened by an OPERATOR, are in their least favourable positions.
 *   Floor-standing equipment has a force of 800 N applied downwards at the 
point of maximum moment to:

*   all horizontal working surfaces;
*   other surfaces providing an obvious ledge and which are not more 
than 1 m above floor
 Doors, drawers, etc. are closed, except that those intended to be opened by an 
OPERATOR are in their least favourable positions.

When the force was applied at the top of the robot mast, it unit started to 
topple at 38 lbs, which is less than the required 44 lb force according to the 
standard.

The case I presented why this test was not applicable was:

  *   because the robot mast is located in the center of of the unit, and not 
flush with the sides, that it did not represent the same situation as a 
bookcase, filing cabinet, or other product which if someone were to bump into 
it, they would not be contacting the robot mast to due to the location in the 
center of the top.
  *   the robot mast is part of a component and not part of the structure of 
the product, and so the test should be done at the top of the base unit, and no 
higher.
  *   there is text in the user manual that says not to push on the robot mast 
when moving the product to new location
  *   and, if absolutely necessary, we an add do not push labels at the top 
sides of the robot mast
The NRTL rejected my rationale so I am looking to you to get your thoughts on 
this before I press on with them.

Do you think the test is applicable?

You can respond here publicly or privately, or at 
stev...@productehsconsulting.com

Thanks in advance,

Steve Brody
sgbr...@comcast.net
C - 603 617 9116


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