SIST EN 786:1996+A2:2010

SLOVENSKI STANDARD
SIST EN 786:1996+A2:2010
01-februar-2010
2SUHPD]DQHJRYUWD(OHNWULþQRJQDQHURþQRYRGOMLYHLQSUHQRVQHPRWRUQHNRVH
]DWUDWHLQURERYHWUDW0HKDQVNDYDUQRVW
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 à
conducteur à pied - Sécurité mécanique
Ta slovenski standard je istoveten z: EN 786:1996+A2:2009
ICS:
65.060.70 Vrtnarska oprema Horticultural equipment
SIST EN 786:1996+A2:2010 en,fr
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 786:1996+A2:2010

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SIST EN 786:1996+A2:2010


EUROPEAN STANDARD
EN 786:1996+A2

NORME EUROPÉENNE

EUROPÄISCHE NORM
October 2009
ICS 65.060.70 Supersedes EN 786:1996
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 European Standard was approved by CEN on 20 April 1996 and includes Corrigendum 1 issued by CEN on 12 August 1996,
Amendment 1 approved by CEN on 4 February 2001 and Amendment 2 approved by CEN on 10 August 2009.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.

This European Standard 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 CEN Management Centre has the same status as the
official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.






EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 786:1996+A2:2009: E
worldwide for CEN national Members.

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SIST EN 786:1996+A2:2010
EN 786:1996+A2:2009 (E)
Contents Page
Foreword .3
Introduction .4
1 Scope .4
2 Normative references .4
3 Definitions .5
4 Safety requirements and/or measures .6
4.1 Handling .6
4.2 Protection of power driven transmission parts (other than the cutting means) .7
4.3 Guard attachment .7
4.4 Controls .7
4.5 Cutting means .7
4.6 Guarding of cutting means .8
4.7 Mechanical strength and rigidity .8
4.8 Vibration . 12
4.9 Noise . 13
5 Information for use . 14
5.1 Instruction handbook . 14
5.2 Marking . 15
Annex A (normative) List of hazards . 17
Annex B (normative) Calculation of kinetic energy . 21
Annex C (informative) Acceptable symbols for machine marking . 22
Annex D (normative) !!Vibration"" . 23
!! ""
Annex E (normative) Noise test code – Engineering method (grade 2) . 26
Annex F (informative) ####Example of a material and construction fulfilling the requirements for an
artificial surface$$$$ . 31
Annex ZA (informative)  ##Relationship between this European Standard and the Essential
##
Requirements of EU Directive 98/37/EC$$$$ . 33
Annex ZB (informative) ##Relationship between this European Standard and the Essential
##
Requirements of EU Directive 2006/42/EC$$$$ . 34
Bibliography . 35

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SIST EN 786:1996+A2:2010
EN 786:1996+A2:2009 (E)
Foreword
This document (EN 786:1996+A2:2009) 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 European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by April 2010, and conflicting national standards shall be withdrawn at the
latest by April 2010.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This European Standard was approved by CEN on 20 April 1996 and includes Corrigendum 1 issued by CEN
on 12 August 1996, Amendment 1 approved by CEN on 4 February 2001 and Amendment 2 approved by
CEN on 10 August 2009.
This document supersedes EN 786:1996.
The start and finish of text introduced or altered by amendment is indicated in the text by tags
!" and # $.
The modifications of the related CEN Corrigendum have been implemented at the appropriate places in the
text and are indicated by the tags ˜ ™.
#This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association, and supports essential requirements of EU Directive(s).
For relationship with EU Directive(s), see informative Annexes ZA and ZB, which are integral parts of this
document.$
The Annex A is normative and contains the "List of hazards".
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and United Kingdom.
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SIST EN 786:1996+A2:2010
EN 786:1996+A2:2009 (E)
Introduction
The extent to which hazards are covered is indicated in the scope of this standard. In addition machinery shall
comply as appropriate with EN 292 for hazards which are not covered by this standard.
The electrical safety aspects of lawn trimmers and lawn edge trimmers will be covered by a standard presently
under development by CLC/TC 61F.
Walk-behind machines with metal cutting elements or cutting elements with greater than 10 J kinetic energy
will be covered by a standard presently under development by CEN/TC 144/WG 7.
1 Scope
This European Standard specifies mechanical safety requirements and testing for the design and construction
of electrically powered walk-behind and hand-held lawn trimmers and lawn edge trimmers, with cutting
element(s) of non-metallic filament line or freely pivoting non-metallic cutter(s) with a kinetic energy of not
more that 10 J each, and used by a standing operator primarily for cutting grass.
It describes methods for the elimination or reduction of hazards arising from their use. In addition, it specifies
the type of information to be provided by the manufacturer on safe working practices.
This standard is not applicable to:
a) Scissor type or lawn trimmers and lawn edge trimmers with cutting means other than those described
above;
b) Self-propelled lawn trimmers or lawn edge trimmers;
c) Lawn trimmers or lawn edge trimmers which do not have a distance of at least 600 mm between the
cutting means control and the cutting head.
The electrical aspects of electrically powered lawn trimmers and lawn edge trimmers are not covered by this
standard.
The list of significant hazards dealt with in this standard is given in annex A. Annex A also indicates the
hazards which have not been dealt with.
Environmental aspects have not been considered in this standard.
This European Standard applies primarily to machines which are manufactured after the date of issue of this
standard.
NOTE The method of calculating the kinetic energy for the purposes of this standard is given in annex B.
2 Normative references
This European Standard incorporates by dated or undated references, provisions from other publications.
These normative references are cited at the appropriate places in the text and the publications are listed
hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to
this European Standard only when incorporated in it by amendment or revision. For undated references the
latest edition of the publication referred to applies.
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SIST EN 786:1996+A2:2010
EN 786:1996+A2:2009 (E)
EN 292-1:1991, Safety of machinery - Basic concepts, general principles for design - Part 1: Basic
terminology, methodology
EN 292-2:1991, Safety of machinery - Basic concepts, general principles for design - Part 2: Technical
principles and specifications
!EN 292-2:1991/A1:1995, Safety of machinery - Basic concepts, general principles for design – Part 2:
Technical principles and specifications"
EN 294:1992, Safety of machinery – Safety distances to prevent danger zones being reached by the upper
limbs
!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)"
ISO 3767-1:1991, Tractors, machinery for agriculture and forestry, powered lawn and garden equipment –
Symbols for operator controls and other displays – Part 1: Common symbols
ISO 3767-3:1995, Tractors, machinery for agriculture and forestry, powered lawn and garden equipment –
Symbols for operator controls and other displays – Part 3: Symbols for powered lawn and garden equipment
3 Definitions
For the purposes of this standard the following definitions apply:
3.1
hand-held
supported by hand, possibly assisted by wheel(s), skids or harness, etc.
3.2
walk-behind
ground supported, controlled by an operator walking behind
3.3
lawn trimmer
grass trimming machine where the cutting means operates in a plane approximately parallel to the ground
3.4
lawn edge trimmer
grass trimming machine where the cutting means operates in a plane approximately perpendicular to the
ground
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EN 786:1996+A2:2009 (E)
3.5
cutting means
mechanism used to provide the cutting action in which one or more cutting elements, cutting by impact, rotate
about an axis normal to the cutting plane
3.6
cutting element
single non-metallic filament line or freely pivoting non-metallic cutter
3.7
cutting head
a support system for the cutting element
3.8
cutting means control
a device activated by the operator's hand or finger, for controlling the cutting means movement
4 Safety requirements and/or measures
4.1 Handling
Hand-held lawn trimmers and lawn edge trimmers shall have at least one handle.
All hand-held lawn trimmers and lawn edge trimmers with a mass of more than 3,5 kg shall have two handles
and the distance between the centres of the two handles shall be at least 250 mm.
NOTE This measurement of 250 mm does not apply to two handled lawn trimmers with a mass of 3,5 kg or less.
Additionally, hand-held law trimmers and lawn edge trimmers with a mass of more than 6 kg shall also have at
least a single shoulder harness and those with a mass of more than 7,5 kg shall have a double shoulder
harness.
The mass of the machine shall be determined in its heaviest condition for normal use and without cable.
The gripping length of any handle required by this standard shall be at least 100 mm.
If a part containing the motor complies with the dimensions pertaining to handles it may be considered as a
handle.
The gripping length of a bail or closed handle shall comprise any length that is straight or curved at a radius of
greater than 100 mm together with any blend radius but not more than 10 mm at either or both ends of the
gripping surface.
If a straight handle is supported centrally (i.e. 'T' type) the gripping length shall be calculated as follows:
a) For handles with a periphery (not including the support) less than 80 mm the gripping length is the sum of
the two parts either side of the support.
b) For handles with a periphery (not including the support) of 80 mm or more the gripping length is the
complete length from end to end.
Where appropriate the part of the handle containing the cutting means control actuator shall be counted as
part of the handle gripping length. Finger grip or similar superimposed profiles shall not affect the method of
calculating handle gripping length.
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4.2 Protection of power driven transmission parts (other than the cutting means)
All power driven transmission parts shall be guarded to prevent the operator's contact with these parts.
All apertures and safety distances shall conform to 4.5.1 and 4.5.3 of EN 294:1992. Compliance shall be
checked by inspection.
4.3 Guard attachment
All guards required by this standard shall be fixed guards in accordance with 3.22.1 of EN 292-1:1991 or the
construction of the machine shall be such that it cannot be used without the guard in its guarding position in
accordance with 3.22.4 of EN 292-1:1991.
4.4 Controls
4.4.1 One cutting means control shall be provided and either this shall require two separate and dissimilar
actions before the cutting elements can be driven or the control shall be guarded to prevent inadvertent
operation. There shall be no means of locking this control in the 'on' position and the cutting element shall
come to rest when the control is released.
Compliance shall be checked by inspection and for a guarded cutting means control it shall not be possible to
operate the control by means of a (100 ± 1) mm diameter solid sphere.
4.4.2 Controls, where the purpose is not obvious, shall have the function, direction and method of operation
clearly identified by a durable marking.
Detailed instructions on the operation of all controls shall be provided in the instruction handbook (see 5.1).
NOTE Symbols in accordance with ISO 3767-1 and ISO 3767-3 may be used as appropriate.
4.5 Cutting means
4.5.1 A cutting means shall consist of one or more non-metallic cutting elements mounted on or emergent
from a generally circular cutting head.
4.5.2 A cutting element shall consist of one of the following (see figure 1):
a) A non-metallic filament line; or
b) A non-metallic freely pivoting cutter.
Machines having cutting means using one or more cutting elements of continuous filament line (e.g. wound on
a spool contained either in the cutting head or other attachment) shall incorporate a means to automatically
limit the line to its correct operating length after the line has been extended and/or the machine is operated.
The machine manufacturer shall not supply metallic cutting elements which can replace the non-metallic ones.
4.5.3 The kinetic energy of a cutting element shall be determined in accordance with annex B.
Polyamide cutting elements shall be stored at (20 ± 3) °C and atmospheric humidity for at least seven days
before testing.

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a) Filament line (see 4.5.2a))   b) Pivoting cutter (see 4.5.2b))
Figure 1 — Cutting means
4.6 Guarding of cutting means
4.6.1 General
Guards shall be imperforate and not be detachable without the use of a tool.
NOTE As an alternative to the guarding requirements of 4.6 a thrown object test is under study. If this is approved it
will offer alternative guarding specifications for some or all configurations of lawn trimmers and lawn edge trimmers.
4.6.2 Lawn trimmers
Lawn trimmers shall be guarded on the operator's side as a minimum, to the extent shown in figure 2. The
radius 'x' of the guard shall not be smaller than the major swept radius of the cutting head, and the guard shall
extend beyond the plane of the cutting element by at least 3 mm for walk-behind lawn trimmers and at least
10 mm for hand-held lawn trimmers. The guard shall extend at least 45° from the axis of the handle on the
side where the cutting element is moving away from the operator and at least 90° from the axis of the handle
on the side where the cutting element is moving towards the operator.
NOTE The vertex of the angle lies on the axis of the cutting head spindle
4.6.3 Lawn edge trimmers
Lawn edge trimmers shall be guarded, as a minimum, to the extent shown in figure 3. The radius 'y' of the
guard shall not be smaller than the major swept radius of the cutting head. The guard shall extend beyond the
plane of the cutting element by at least 10 mm. With the lawn edge trimmer in its normal position of use the
guard shall extend a minimum of 90° from the vertical towards the ground on the side where the cutting
element is moving upwards and a minimum of 45° from the vertical towards the ground on the side where the
cutting element is moving downwards.
NOTE The vertex of the angle lies on the axis of the cutting head spindle
4.7 Mechanical strength and rigidity
4.7.1 General
All the tests of 4.7 shall be carried out when the temperature of the parts to be tested has stabilized to an
ambient temperature of (20 ± 3)°C.
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4.7.2 Cutting means guard (mechanical strength and rigidity)
4.7.2.1 The mechanical strength and rigidity of cutting means guards of trimmers shall be adequate for
normal use. Compliance shall be checked by the tests given in 4.7.2.2 and 4.7.2.3 or 4.7.2.4.
After the tests the guard shall not have become detached nor show any visible cracks. Screws and retaining
clips shall be secure and the requirements of 4.6.2 or 4.6.3 shall still be met.
4.7.2.2 The rigidity of the guard shall be checked by applying a force, at any point, equivalent to the weight
of the trimmer in the most unfavourable direction for 30 s.
4.7.2.3 The strength of guards of walk-behind lawn trimmers and walk-behind lawn edge trimmers shall be
tested by means of the following ball impact test.
Each of the three samples of the complete machine shall be subjected to an impact of (6,5 ± 0,2) J on a part
of the guard likely to be the weakest, with the lawn trimmer or lawn edge trimmer resting on a smooth, rigid,
level surface.
The tests shall be conducted so that each of the three samples receives an impact in a location different from
the other two.
The impact shall be produced with a smooth solid steel sphere (as used for ball bearings) having a diameter
of 50 mm. If the part being tested is at an angle of up to 45° to the horizontal, the sphere shall be allowed to
fall vertically from rest to strike the part. Otherwise, the sphere shall be suspended by a cord and shall be
allowed to fall from rest as a pendulum to strike the part. In either case, the vertical travel of the sphere shall
be 1.3 m.
4.7.2.4 The strength of guards of hand-held lawn trimmers and hand-held lawn edge trimmers shall be
tested by means of the following drop test.
NOTE A string should be used to suspend the machine so that the desired orientation of the machine can be
achieved. Cutting the string will allow the machine to fall in the correct orientation to test the guard or the cutting head.
One sample of the complete machine without supply cord shall be dropped three times so that the guard falls
through a vertical distance of 0,9 m onto a smooth horizontal concrete surface in such a manner as to test the
guard most severely (see figure 4).
4.7.3 Cutting head (mechanical strength)
4.7.3.1 The mechanical strength of the cutting head shall be adequate for normal use. Compliance shall be
checked by the test given in 4.7.3.2.
NOTE A string should be used to suspend the machine so that the desired orientation of the machine can be
achieved. Cutting the string will allow the machine to fall in the correct orientation to test the guard or the cutting head.
4.7.3.2 The complete machine shall be dropped so that the cutting head, in a horizontal plane, falls through
a vertical distance to make contact with a rigidly supported horizontal steel block. The drop height shall be
0,9 m for hand-held lawn trimmers and lawn edge trimmers and 0,25 m for walk-behind (see figure 5).
NOTE It is not necessary for the machine to be operable after the test.
If the machine is operable then immediately following this test the machine shall be run at its maximum speed
for 30 s both with and without cutting elements.
If the machine will not work after the test but the cutting head is not visibly damaged and if the cutting head is
designed to be replaceable then the cutting head shall be fitted to a new machine and run at maximum speed
for 30 s both with and without the cutting element(s) fitted.
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SIST EN 786:1996+A2:2010
EN 786:1996+A2:2009 (E)
No parts shall become detached and no visible cracks shall have developed.
Dimensions in millimetres
!
RP
90° min
1
45° min
2
RP
3

a) Plan view
4
5
6 RP
CP
'a'

b) 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)
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SIST EN 786:1996+A2:2010
EN 786:1996+A2:2009 (E)
Dimensions in millimetres
A
3 CP
45°min
RP
90° min
RP
4
1
RP
5
2
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)""""
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EN 786:1996+A2:2009 (E)
Dimensions in metres
1
2

NOTE A string should be used to suspend the machine so that the desired orientation of the machine can be
achieved. Cutting the string will allow the machine to fall in the correct orientation to test the guard or the cutting head.
Figure 4 — Guard strength test (see 4.7.2.4)

Dimensions in metres
1
2 3

NOTE A string should be used to suspend the machine so that the desired orientation of the machine can be
achieved. Cutting the string will allow the machine to fall in the correct orientation to test the guard or the cutting head.
Figure 5 — Cutting head strength test (see 4.7.3)
!
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 :
12
a
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SIST EN 786:1996+A2:2010
EN 786:1996+A2:2009 (E)
 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 m
...