EN 786:1996/A1:2001

SLOVENSKI STANDARD
01-december-2001
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Garden equipment - Electrically powered walk-behind and hand-held lawn trimmers and
lawn edge trimmers - Mechanical safety
Gartengeräte - Elektrisch betriebene handgeführte und handgehaltene Rasentrimmer
und Rasenkantentrimmer - Mechanische Sicherheit
Matériel de jardinage - Coupe-gazon et coupe-bordures électriques portatifs et a
conducteur a pied - Sécurité mécanique
Ta slovenski standard je istoveten z: EN 786:1996/A1:2001
ICS:
65.060.70 Vrtnarska oprema Horticultural equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 786:1996/A1
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2001
ICS 65.060.70
English version
Garden equipment - Electrically powered walk-behind and hand-
held lawn trimmers and lawn edge trimmers - Mechanical safety
Matériel de jardinage - Coupe-gazon et coupe-bordures Gartengeräte - Elektrisch betriebene handgeführte und
électriques portatifs et à conducteur à pied - Sécurité handgehaltene Rasentrimmer und Rasenkantentrimmer -
mécanique Mechanische Sicherheit
This amendment A1 modifies the European Standard EN 786:1996; it was approved by CEN on 4 February 2001.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for inclusion of this
amendment into the relevant national standard without any alteration. Up-to-date lists and bibliographical references concerning such
national standards may be obtained on application to the Management Centre or to any CEN member.
This amendment exists in three official versions (English, French, German). A version in any other language made by translation under the
responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2001 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 786:1996/A1:2001 E
worldwide for CEN national Members.

Page 2
Foreword
This Amendment EN 786:1996/A1:2001 to EN 786:1996 has been prepared by Technical Committee CEN/TC 144
"Tractors and machinery for agriculture and forestry", the secretariat of which is held by AFNOR
This Amendment to the European Standard EN 786:1996 shall be given the status of a national standard, either by
publication of an identical text or by endorsement, at the latest by September 2001, and conflicting national
standards shall be withdrawn at the latest by September 2001.
This Amendment to the European Standard EN 786:1996 has been prepared under a mandate given to CEN by
the European Commission and the European Free Trade Association, and supports essential requirements of EU
Directive(s).
For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this standard.
This amendment which specifically deals with the garding of cutting means, vibration and noise, replaces :

the previous Figures 2 and 3 ; and

the "Not yet dealt with" notes in the right hand column of Table A.1 against hazard items 4.1, 4.2 and 5 listed in
the left hand column.
Annexes D and E are normative. Annex F is informative.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,
France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden,
Switzerland and the United Kingdom.

Page 3
2 Normative references
Add the following references:
EN 292-2:1991/A1:1995, Safety of machinery - Basic concepts, general principles for design – Part 2: Technical
principles and specifications.
EN 836:1997, Garden equipment - Powered lawnmowers – Safety.
EN 28662-1:1992, Hand-held portable power tools - Measurement of vibrations at the handle – Part 1: General
(ISO 8662-1:1988).
EN ISO 354:1993, Acoustics – Measurement of sound absorption in a reverberation room (ISO 354:1985).
EN ISO 3744:1995, Acoustics - Determination of sound power levels of noise sources using sound pressure -
Engineering method in an essentially free field over a reflecting plane (ISO 3744:1994).
EN ISO 11201:1995, Acoustics - Noise emitted by machinery and equipment - Measurement of emission sound
pressure levels at a work station and at other specified positions - Engineering method in an essentially free field
over a reflecting plane (ISO 11201:1995).
EN ISO 11688-1:1998, Acoustics - Recommended practice for the design of low-noise machinery and equipment –
Part 1: Planning (ISO/TR 11688-1:1995).
4 Safety requirements and/or measures
4.6 Guarding of cutting means
Replace the Figures 2 and 3 by the following:

Page 4
Dimensions in millimetres
RP
90° min
45° min
RP
Figure 2a - Plan view
RP
CP
'a'
Figure 2b - Side view
KEY
1 Radius ‘X’ 4 Handle shaft
2 Maximum radius of cutting element 5 Guard
3 Direction of rotation 6 Cutting head
a = 3 min for walk-behind machines a = 10 min for hand-held machines
NOTE 1 For reasons of clarity, any skids or wheels are not shown in the figures. The figures are not intended
to govern design except as regards the dimensions and specific requirements shown
NOTE 2 Figures are not to scale
o o
NOTE 3 If the direction of rotation is reversed the 45 and 90 guarding requirements are reversed
NOTE 4 The reference point ‘RP’ is where the centre-plane of the cutting element ’CP’ intersects the outer
edge of the guard
Figure 2 — Guard, lawn trimmer (see 4.6.2)

Page 5
Dimensions in millimetres
A
CP
45°
min
RP
90° min
RP
RP
A 10 min
Figure 3a — View towards cutting means Figure 3 b — Part section at AA (guard only)
KEY
1 Direction of rotation 4 Maximum radius of cutting element
2 Radius "Y" 5 Plane of lawn edge
3 Guard
NOTE 1 For reasons of simplification the handle and any skids or wheels are not shown in the figures. The figures are not intended to govern the design except as regards
the dimensions and the specific requirements shown
NOTE 2 Figures are not to scale
o o
NOTE 3 If the direction of rotation is reversed the 45 and 90 guarding requirements are transposed
NOTE 4 The reference point ‘RP’ is where the centre plane of the cutting element ‘CP’ intersects the outer guard edge
Figure 3 — Guard, lawn edge trimmer (see 4.6.3)

Page 6
Add the following sub-clauses 4.8 and 4.9:
4.8 Vibration
The requirements of 4.8 apply to hand-held lawn trimmers and hand-held lawn edge trimmers. The methods for
vibration measurements given in EN 836:1997 are valid for walk-behind lawn trimmers and walk-behind lawn edge
trimmers.
4.8.1 Reduction by design and protective measures
The machine shall be designed to generate a vibration level as low as practicable. The main sources causing
vibration are the :

oscillating forces from the motor ;

cutting means ;

unbalanced moving parts ;

impact in gears, bearings and other mechanisms ;

interaction between operator, machine and material being worked.
NOTE 1 CR 1030-1:1995 gives general technical information on widely recognised technical rules and means to be followed
in the design of machines for low hand-arm vibration solutions.
NOTE 2 Besides the vibration reduction of the source, technical measures to isolate the vibration source from the handle
may be used, when appropriate, such as isolators and resonating masses.
4.8.2 Reduction by information
After taking possible technical measures for vibration reduction, it is still recommended that, when appropriate, the
instruction handbook recommends :

the use of low-vibration operating modes, and/or limited time of operation ;

the wearing of personal protection equipment (PPE).
4.8.3 Vibration measurement
For the measurement of hand-arm vibration the methods given in Annex D shall be used.
4.9 Noise
The requirements of 4.9 apply to hand-held lawn trimmers and hand-held lawn edge trimmers. The methods for
noise measurements given in EN 836:1997 are valid for walk-behind lawn trimmers and walk-behind lawn edge
trimmers.
4.9.1 Reduction as a safety requirement
4.9.1.1 Reduction at source by design and protective measures
The machine shall generate a noise level as low as practicable. The main sources causing noise are:

air intake system ;

engine cooling system ;

cutting system ;

vibrating surfaces.
EN ISO 11688-1:1998 gives general technical information on widely recognised technical rules and means to be
followed in the design of low-noise machines.

Page 7
4.9.1.2 Reduction by information
If after taking all possible technical measures for reducing noise at the design stage a manufacturer considers that
further protection of the operator is necessary, then the instruction handbook shall:

recommend the use of low-noise operating modes, and/or limited time of operation ;

give a warning of the noise level and recommend the use of ear protection.
4.9.2 Noise emission measurement
The determination of the sound power level and of the emission sound pressure level at the operator’s position
shall be carried out using the measurement methods given in Annex E.
5 Information for use
5.1 Instruction handbook
5.1.1 General
Insert the following paragraph:
The instruction handbook and the technical documentation describing the machine shall :

give the declared noise emission values of the machinery in accordance with 1.7.4 f) of Annex A of
EN 292-2:1991/A1:1995;

give reference to the noise test code specified in Annex E;

give the declared vibration values of the machinery in accordance with 3.6.3 of Annex A of
EN 292-2:1991/A1:1995;

give reference to the vibration test code specified in Annex D.

Page 8
Annex A
Amend Table A.1, rows 4.1, 4.2 and 5 as follows:

 


 


 

 

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Add the following Annexes D and E (normative) and Annex F (informative):

Page 9
Annex D
(normative)
Vibration
D.1 Quantities to be measured
The values measured shall be:

acceleration according to 3.1 of EN 28662-1:1992, presented as weighted acceleration a according to 3.3 of
h,W
EN 28662-1:1992 ;

rotational speed of the engine.
D.2 Instrumentation
D.2.1 General
For specification of instrumentation see 4.1 of EN 28662-1:1992.
D.2.2 Transducer
For specifications of transducer see 4.1 of EN 28662-1:1992.
D.2.3 Fastening of transducer
Fastening of transducer shall be in accordance with 4.2 of EN 28662-1:1992.
D.2.4 Calibration
Calibration shall be made in accordance with 4.8 of EN 28662-1:1992.
D.3 Measurement direction and measurement location
D.3.1 Measurement direction
Measurements shall be made on each handle for the 3 directions x, y and z (see Figure D.1).
D.3.2 Measurement location
Typical locations of the transducer assemblies and directions of measurement are shown in Figure D.1.
D.4 Test procedure
D.4.1 Determination of working procedure
Tests shall be carried out on a new, normal production machine featuring standard equipment with the machine
provided by the manufacturer.
The machine shall be run until stable conditions are reached before the test is commenced. Filament line(s), if any,
shall be at the correct operating length. All speed setting devices shall be adjusted to the highest figure.
The rated voltage or the upper limit of the rated voltage range and/or frequency shall be maintained during the test
at 0,98 to 1,02 times the stated values. The supply voltage of mains powered machines is measured at the plug of
the cable or cord supplied, not at the plug of any extension cable or cord. Battery powered machines shall be
powered by an external power source maintained at the nominal voltage of the battery.
During the test the cutting means shall be driven. Contact between the hand and the transducer shall be avoided.

Page 10
D.4.2 Measurement procedure
For each handle a series of five tests shall be carried out using one operator. Adjustable handle(s) shall be set to
the mid-position. If a harness is provided it shall be used during the test. The machine handle(s) shall be held in the
normal operating position with the plane of the cutting means parallel or perpendicular to the ground, as
appropriate, and within 50 mm of the ground. The cutting means shall be free of all obstructions.
NOTE 1 Issues such as the validity of the tests and the number of test operators are to be considered for future revision in
the light of experience gained using the present test method.
Each reading shall be obtained from the signal time suitable for the test equipment being used. Duration of the test
shall not be less then 8 s.
NOTE 2 An equivalent level of accuracy may be achieved by using a shorter duration than 8 s. In this case the equivalence
of the results should be justifiable.
Measurement for the three directions (see D.3.1) shall be made simultaneously.
D.5 Determination of the measurement result
The measurement result of each handle shall be determined as the arithmetic mean over the a value of each
h,W
test. If a single figure is quoted it shall be the higher of the two.

Page 11
Dimensions in millimetres
X
Y
X
X
Y
Z
X
Y
Z
NOTE If the measurements o
...