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          Safety Principles for
                 METAL
                CUTTING
            GUILLOTINES




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Important Note:
All the publications in the Publications Archive
contain the best guidance available at the time of
publishing. However, you should consider the
effect of any changes to the law since then. You
should also check that the Standards referred to
are still current.




Published 1980
Reformatted 2004




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CONTENTS
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FOREWORD                              4
Introduction                          5
Definition                            5
Accident Causes                       5
Requirement of Machinery Act 1950     6
Prime Mover and Transmission          6
Dangerous Parts — Blade and Clamp     6
Manual or Treadle Operated Machines   7
Power-Operated Machines               9
Back Guard                            17
Guard Design                          20
Other Publications                    21




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FOREWORD

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       It has been recognised for a number of years that the guillotine is a dangerous
       machine when used in an unguarded state and therefore the object of this booklet is
       to illustrate types of guards for metal cutting guillotines used throughout the engineer-
       ing industry and machines of similar character used in other industries.
       In issuing this booklet opportunity has been taken to illustrate not only conventional
       methods of guarding but also to show how methods of aiding production such as
       mechanical handling can be contrived to promote as well as facilitate tidiness and
       general good industrial housekeeping.
       The booklet recognises the dangerous character of the guillotine blade whetherit is
       operated by foot or by power.
       The Department of Labour appreciates the assistance given by both industry and
       manufacturers in the preparation of the contents of this booklet which has the support
       and agreement of industry.




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                                                                                  (c) Strip cutting.
                                                                                         (b)Trimming
                                                                                   (a) Plain cutting
                                               Three types of cutting are done with guillotines:
    be the loss of only one finger tip or it may be the loss of all the fingers of one hand.
    that do occur on guillotines are serious and involve some degree of mutilation. It may
    high. But what can be said with reasonable certainty is that the majority of accidents
    total number of injuries from all causes, the number of guillotine accidents is not very
    It is probable that in relation to the number of guillotines in use or in relation to the
    have a severity which is out of all proportion to their frequency.
    Accidents on guillotines like those on power presses and similar types of machinery,
                                                                                              Accident Causes
    shears, or billet shears.
    substances, but for the purpose of this booklet does not include alligator shears, bar
    or bevel-edged blade operating vertically against resisting edges used for shearing
    The term “metal cutting guillotine” means a machine usually equipped with a square
                                                                                                         Definition
                                                 Fig. 1
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                                                   FIBRE
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                                                                    LEATHER
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                                        RUBBER
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               VENEER               987654321                                               321
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     hope that designers and users will be stimulated to further development.
     guarding; rather it is put forward in order to show what has been done, and in the
     The information given is not intended to be the last word on the subject of guillotine
     the metal trades industry, have application to these.
     illustrated in figure 1 and the examples of guarding shown, while drawn mainly from
     however machines of similar character used in other industries for cutting materials
     The metal cutting guillotine is used mainly in the engineering industry. There are

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                                                                                                       Introduction
                                                                                                  IVE
   HIVE    During strip cutting, particularly the cutting of strip in series where an attempt is made


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           to keep the percentage of waste as low as possible, the operator is inclined to put his
           hands as close to the blade as he can. This increases the risk of injury.

A          Clamps are usually employed on power-operated guillotines and unless the stroke of
           the clamp is so small as to preclude the entry of the fingers below the clamp injuries
           can occur.
           Many accidents have also occurred when work is being fed from the back of the
           machine. Guillotines are intended to be worked from the front. However, it has been
           found that, on repetition work to fine limits, the work can be more easily done by a
           person feeding the sheet from the back to a front stop; the cut pieces being removed
           by an operator at the front. This is a particularly hazardous method of working
           because the person at the rear may be out of sight whilst manipulating work close to
           the blade and inadvertent engagement of the clutch or power control by the operator
           in front may result in a serious accident.
           Accidents have also occurred where an operator has reached through the throat of
           the machine to locate or position work, and has either inadvertently or with intent
           engaged the clutch or power control.


Requirement of Machinery Act 1950
           The MachineryAct 1950 requires that the moving parts of the prime mover, every
           part of any transmission machinery, and every dangerous part of any other machinery
           be securely fenced, unless the parts are in such a position or of such construction as
           to be as safe to every person employed or working on the premises as they would
           be if securely fenced.
           These requirements can be met in respect of metal cutting guillotines by:
              (a) Complete enclosure of the prime mover and transmission.
              (b) Fitting a guard which will prevent a worker from coming into contact with the
                  blade or clamp when the machine is in motion.


Prime Mover and Transmission
           The prime mover of the individual electric motor type is usually completely enclosed
           except for the shaft end on to which the transmission pulley is secured. Good design
           of the guard for the transmission will ensure enclosure of the shaft end as well as the
           transmission.
           The transmission should be securely fenced in terms of the Department’s leaflet
           Guarding Transmission Machinery.


Dangerous Parts — Blade and Clamp
           The dangerous character of guillotine blades, whether operated by foot or by power,
           has long been recognised, and the need for effective guarding is clear. For most
           purposes and especially in the case of finished flat sheet a static fixed guard can and
           should be used in preference to any other type.



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Manual or Treadle Operated Machines
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           For the simple treadle guillotine without clamp, the fixed guard should be set close to
           the blade so as to prevent the finger tips of the operator reaching the blade. Care
           should be taken to see that the guard is arranged to prevent access over the top and
           also at the ends.
           The guard will also he effective from the back of the machine if it is set vertically, in
           rubbing contact with the blade and sothat the feed opening extends to no more than
           6 mm above the table. If the bottom edge of the guard is chamfered it will assist
           feeding.
           This principle of a fixed guard applied to a treadle or light power operated guillotine
           without clamp is illustrated in figures 2 and 3. The guard A is a plate supported on
           the rail B and held in contact with the blade by set screw C at each end. The gap
           between the underside of the guard and the table Another method of providing a
           fixed guard for a treadle is 6 mm and, provided care is taken that the guard is
           maintained in contact with the blade, it should not be possible for the fingers to pass
           between the blade and approached from the front or back.




                                                     Fig. 2




                                                     Fig. 3


           Another method of providing a fixed guard for a treadle-operated guillotine without
           clamp is shown in figure 4. The front guard is set at an angle to provide for sighting
           the work. This is necessary when cutting to a line. A simple form of back guard is
           also shown.

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                                           Fig. 4
    Figures 5 and 6 show yet another method of guarding the back of a treadle guillotine.
    The guard provides a feed opening for stock and a lower opening with deflector
    plate for cut pieces which are pushed off the table beneath the front guard.
    On some designs of treadle operated guillotines clamps are provided; these clamps
    are designed to come into operation as the treadle is depressed. They secure the
    material and also provide a guard to the blade as they arc usually positioned at a
    maximum distance of 6 mm above the table.




                                           Fig. 5




                                           Fig. 6

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           However, many manufacturers destroy its use as a guard by adopting multi-point


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           contacts intended to ensure that the material is firmly gripped. These multi-point


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           contacts are provided by shaping the clamp as shown in figure 7 and inset A.
           Accidents have occurred when an operator has extended his finger through the gaps
           to hold material when cutting narrow strips. His finger has reached the blade. Inset B
           shows a method of overcoming this difficulty by chamfering finger recesses in the
           clamp.
           In order to prevent injury to the operator’s foot from the descending treadle, floor
           stops should be provided. This is shown in figure 8.




                                                   Fig. 7




                                                   Fig. 8


Power-operated Machines
           As previously stated a fixed guard is practicable and should always be used in
           preference to any other type of guard. However, a problem often arises because of


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     the wavy nature of the metal as delivered for shearing making it difficult to pass the


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     sheet through a narrow opening. Such a difficulty can often be dealt with by making
     the feed opening in the guard sufficiently large to pass the sheet. However, it should

A    be set at such a distance from the blade or clamp as to prevent finger tips from
     reaching them.
     While the effectiveness of any fixed guard must always be judged by a test to see
     that the finger tips cannot reach the point of danger, the following formula is used by
     the Department of Labour as a guide to the setting of a guard.
     Minimum distance of guard
           opening from danger point = 10 x (guard opening — 6 mm)
     The relationship between guard opening and distance from the danger point is shown
     in table 1 below:
                                             Table 1.

                  Minimum clearance between              Maximum width of
                    guard and dangerous part                  opening

                           0-25   mm                             6   mm
                             50   mm                            13   mm
                            100   mm                            16   mm
                            130   mm                            19   mm
                            160   mm                            22   mm
                            190   mm                            25   mm
                            220   mm                            28   mm
                            250   mm                            31   mm




                                               Fig. 9

     For trimming operations and other cases where close access to the blade is not
     necessary, a grille guard as shown in figure 9 can be effective. The outer bar, in
     relation to the table, must provide a feed opening at a safe distance from the blade or
     clamp so also must the spacing of each intermediate bar, see table 1.
     Figure 10 shows the guarding arrangement of an electromechanical Edwards
     ‘’Besco-Truecut” machine fitted with a 1.8 m blade, installed at the factory of
     National Radiator Ltd. Wellington. The upper portion of the front guard is set at an
     angle to provide for sighting the work, and is fitted with shadowline lighting for
     accurately cutting to a scribed line.

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     The size of this opening is 28 mm and is situated 225 mm from the nearest trapping


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     point and this complies with table 1. The bottom portion of the guard is situated


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     6 mm above the table and at a distance of 45 mm out from the clamp and 90 mm
     from the blade. This again complies with table l.




                                             Fig. 10
     Many machines are manufactured with an excessive opening at the throat (the open-
     ing at each end of a guillotine used for notching and feeding material wider than the
     machine table) through which an operator can reach to the back of the blade. It has
     been found that although many new machines have this feature it is seldom used. In
     the circumstances the blade is exposed at this point unnecessarily.
     Figure 11 shows a hydraulically operated guillotine manufactured by Dye Industries
     Ltd. Auckland, and shows the throat referred to, and in figure 12 the guarding
     arrangements under taken by the manufacturers to overcome this hazard.
     Where a throat is essential, however, access to the blade and clamp can be pre-
     vented at the feeding side by a tunnel guard which forms an extension of the table
     and front guard.At the delivery side where the sheared metal emerges at two
     levels, a hinged guard, opened only for the slitting of large sheets can be provided.




                                             Fig. 11




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                                              Fig. 12


     The frontal guard shown in figure 11 is positioned at a distance of 10 mm above the
     table and at a distance of 125 mm from the blade. While guards of this type give
     adequate protection for both the blade and hydraulic clamps, a problem does arise
     when it is required to shear narrow work close to the blade.
     Figure 13 shows a Dye guillotine installed at Electrolux Ltd. Wellington, and the
     method adopted to overcome this problem. The bottom portion of the guard is
     arranged with recesses formed into the spaces between the hydraulic clamp feet.
     This provides a safe means of controlling narrow work near to the blade. To prevent
     reaching over the recess into the blade, the top of each recess is filled in with a plate
     to form a roof. (The inset makes this principle clear.)




                                              Fig. 13




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     Figure 14 illustrates a further development of this principle incorporated by the


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     manufacturers in the latest model of the Dye guillotine.


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                         Fig. 14




     The successful application of a fixed guard to the large plate guillotine raises prob-
     lems, because of the thickness of the material being fed to the blade, and also if there
     are bends in the plate.
     The size of opening in such a guard would necessarily have to be large enough to
     allow the plate to pass under the guard and to prevent a person reaching through the
     opening to be trapped by the blade or clamp. Such an opening would require to be
     at a distance corresponding to the values given in table 1.
     This then would prohibit the feeding of narrow material to the blade with the guard in
     position.
     To overcome this problem Dye Industries Ltd. Auckland, fit hinged interlocking
     guards large plate guillotines, and figures 15 and 16 show the guarding arrangement
     as fitted to the 2.4 in x 13 mm plate guillotine.
     This guard consists of a steel frame to which is secured 20 mm wire mesh, which
     covers the full face of the clamps and blade.
     The guard is interlocked with the foot control pedal, so that when the guard is open,
     as shown in figure 15, it is not possible to initiate a closing stroke of either the clamp
     or blade.




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                                            Fig. 15
     To operate the machine the guard must be brought down to the closed position, as
     shown in figure 16, and in this position the feed opening between the bottom of the
     guard and the table is 25 mm and at a distance of 300 mm from the clamps and
     445 mm from the blade.




                                            Fig. 16
     The guard linkage and interlocking arrangement are shown in figures 17 and 18.




                                            Fig. 17

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             The rod controls
         the hydraulic system

                     Guides                                             Lift up guard connected
                      Stop                                              to interlock bar

                   Interlock bar




                                                                              Foot pedal control

                                             Fig. 18


     Figure 19 shows a fixed grill guard fitted to an ordinary guillotine at Dunlop Rubber
     Company’s factory in England and was used for cutting rubber floor tiling sheet of
     10 mm thickness. The guard was designed on the lines of their rubber calender
     guards of the loop and grill type.
     In common with those guards, this guard has the same two advantages; it affords a
     clear view of the dangerous operation, and it permits the use of the fingers close to
     the danger point, while not affording access thereto.
     The guard which is of stout construction and strongly fixed to the framing is in two
     parts, A and B.A is hinged about the top shaft C, and is held in position by the bolts
     which fix the brackets at the ends of the midway bar D to the frame.
     When the bolts are removed, A can be swung up and back out of the way; this
     affords facilities for attending to the knife when required. In order to ensure that a
     power stroke cannot be initiated while the dangerous parts are exposed, this upward
     movement of guard can be interlocked with the power supply by attaching a cam to
     the end of shaft C. Theupward movement of guard forces open by positive means a
     normally closed limit switch.
     This guard can be adopted for cutting sheet or other kinds of material of moderate
     thickness.


                                                          A     C


                                                                    D




                                                 B


                                             Fig. 19

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     Figures 20 and 21 show another method of guarding a guillotine used for cutting


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     rubber sheet and fitted to a pneumatically operated guillotine at Atlas Rubber Co.
     Ltd. Christchurch.

A    Figure 20 shows the feed-in side of the machine. A free running rubber coated roll is
     placed between the bottom of the fixed guard and the table to facilitate feeding. The
     feed-in space formed between the bottom of the roll and the table is 10 mm and is
     positioned 50 mm from the blade.
     Figure 21 shows the guarding arrangement applied to the back of the machine. This
     consists of two free-running rubber coated rolls positioned 22 mm apart and
     165 mm from the blade.




                                             Fig. 20


     Figure 22 shows the guarding arrangements to the feed and discharge sides of a
     guillotine used for cutting veneer at Fletcher Industries Ltd. Gladstone. In order to
     facilitate the feeding of buckled veneer under the fixed guard, the guard was posi-
     tionedto give an opening above the table of 38 mm at a distance from the knife of
     330 mm on either side.




                                             Fig. 21




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                                                    Fig. 22


Back Guard
             Accidents occur when work is being fed from the back of the machine. Guillotines
             are intended to be worked from the front, but it has been found that on repetition
             work to fine limits, the work can be more easily done by a person feeding the sheet
             from the back to a front stop, the cut pieces being removed by an operator at the
             front.
             On this method of working, two operators are required, one at the front to control
             the machine, the other to feed material under the blade from the rear. Whenever a
             machine is attended by more than one operator there is a danger of an accident being
             caused by a misunderstanding. A word or a nod from one man may be misconstrued
             by his colleague who may then set the machine in motion when a hand is in the
             danger zone.
             The design of a back guard to meet such conditions is not easy, but figures 23 and
             24 show methods which can be applied. In figure 23 the guard is carried on a pair of
             rocker levers with counter balance weights so that in conjunction with stopsA-A the
             normal position of the feed slot, which should conform to table 1, is on the same level
             as the top of the fixed blade.




                                      A
                             W


                                                               A


                                                                   W

                                                    Fig. 23

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     In figure 24 the back guard is of the floating type and consists of a frame fitted in


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     guide castings. At the “high” end of the blade, the frame pivots about on pointA,
     fitted in the guide casting and at the “low” end the frame is attached to the blade

A    beam by a crank pin B.
     The upper apron prevents trapping under the blade, and the lower apron prevents
     access to the blade under the guard, and the space between should conform to
     table 1.
     A front guard is, of course, essential under all circumstances.
     When work is performed from the front only, there should nevertheless be guards at
     the back of the machine and these can usually take the form of barriers or screens to
     prevent a person reaching the blades.A worker may go to the back of the machine
     to collect work or trimmings and stumble against the blade at a moment when it is in
     motion.
     Considerable importance is attached to the provisions of means for discharging the
     cut material away from the back of the blade. The simplest arrangement is an inclined
     skid plate. Other useful ideas illustrated are a belt conveyor in conjunction with a
     collecting box and a collection box on wheels which, in association with other
     guarding, could form the guard for the back.
     These ideas are not only valuable for accident prevention but also promote good
     housekeeping, and by helping to direct work into neat piles, render collection and
     disposal more simple.
                                B




                                                                       A
                                              Fig. 24
     Figure 25 shows the back of the machine shown in figure 13, where the guarding of
     this area has been provided by a belt conveyor which is used with a collecting box.




                                              Fig.25

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                                            Fig. 26




                                             Fig 27


     Back guards incorporating a container for cut work are shown in figures 26 and 27.
     The container is a truck, so arranged and constructed that when in the normal posi-
     tion as shown in figure 26 it prevents, with the associated fixed guarding, access to
     the blade. When the truck is withdrawn to remove the cut work, the raised rear edge
     prevents access to the blade. The square openings in the sloping screen are provided
     for gauge adjustment and do not permit access to the blade.
     Figure 28 shows a simple method of guarding the back of a guillotine by the use of
     tubular guarding. The tubes, which combine lightness and strength should be suffi-
     ciently generous in section to give rigidity, and the spacing should comply with the
     principle of reasonable reach through openings so as to prevent a person from
     reaching the blade.At the same time the guard permits access to the gauge
     adjustment.
     Figure 29 shows a back guard which is suitable where there is no feeding from the
     back. The fixed back guard is arranged with an inclined plate so as to form an exit
     chute for delivery of cut material.




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                                                  Fig. 28




                                                  Fig. 29


Guard Design
           The design of a fixed guard should meet the following requirements:
               (a) The guard should prevent hand or other parts of the body from entering the
                   trapping space.
               (b) The guard should be rigid and of adequate strength for the purpose.
           Typical material used for fixed guards are metal rods, slotted plate, expanded metal.
           Transparent plastic can also be used, but this becomes opaque after some time.
           Where metal rods are used in the line of vision of the operator they should, where
           practicable, be arranged vertically rather than horizontally.


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Other Publications
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            Other publications showing the principles of guarding machinery used in the
            engineering industry are available free of charge from any office of the Department of
            Labour District offices of the Department of Labour are located at:
                  Whangarei                Hastings                  Blenheim
                  Auckland                 Palmerston North          Greymouth
                  Manukau                  Masterton                 Christchurch
                  Hamilton                 New Plymouth              Timaru
                  Tauranga                 Wanganui                  Dunedin
                  Rotorua                  Lower Hutt                Invercargill
                  Gisborne                 Wellington
                  Napier                   Nelson




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