The Sewing Machine Workstation

Document Sample
The Sewing Machine Workstation Powered By Docstoc
					                                              ERGONOMIC DESIGN

                                              The Sewing Machine
             Association                      The ergonomic design of sewing             In what order should
              paritaire                       machine workstations aims to               components be adjusted?
              du textile                      encourage adequate body position
                                                                                         The components located nearer the
                                              and reduce movement constraints to a
        Volume 20, Number 1                                                              floor should generally be adjusted
                                              minimum. The layout is not the only
             June 2003                                                                   first, in the following order:
                                              factor in the prevention of professional
                                              injuries, and the way work and             B lateral position of the pedal, and
                                              working methods are organized must           footrest if any ;
                                              also be examined. Elements to              C height of seat and position of
                                              consider include the adjustment of           backrest ;
                                              workstation components and the
                                              selection and maintenance of
                                                                                         D front/back position of footrest ;
                                              equipment. This information bulletin is    e second pedal if any ;
                                              limited to basic notions of ergonomic      f height of table or level of machine
                                              planning for sewing machine                  in case of free-standing machine ;
                                                                                         g material pick up and delivery areas.

                                              TO THE WORKSTATION
                                              When should the workstation
                                              components be adjusted ?
                                              Adjustments should be made or
                                              reviewed every time:                         6                         5
                                              ■ operators change workstations ;
                                              ■ a sewing operation is modified ;               2
                                              ■ the equipment is modified ;                                              1
Le poste d'opératrice de machine à coudre :
                                              ■ pain or discomfort is signaled ;
 un guide pour aider à prévenir les lésions   ■ a new working station is set-up ;
 professionnelles, ASP Habillement, 1996
                                              ■ preventive maintenance is done.                                              3
             ADAPTED BY
    Stéphane Patenaude, ergonomist
           VALIDATED BY
René Dufresne, ergonomist, Apparel ASP        REMEMBER...
                                              ■ Making compromise adjustments, for example in cases where several
                                                operators share one machine, may cause problems for all operators.
                                              ■ Adjustments should be made even for short periods of work, i.e. under
                                                one hour. Discomfort can appear very rapidly when equipment is not
                                                properly adjusted.
ADJUSTMENT OF PEDALS                                                                  Adjustment of sewing pedal
                                                                                     for work in upright position
Types of pedals                                                                      Activating sewing pedals while in an
                                                                                     upright position causes an unbalance
There are two different types of pedal,                                              that can result in injuries to the legs,
with different potential types of                                                    hips and back. These constraints can
constraints:                                                                         be eliminated by:
■ The sewing pedal is pressed during                                                 ■ using thinner pedals so part of the
  the entire sewing operation.                                                         foot remains on the floor ;
■ The on/off pedal is pressed down to                                                ■ linking pedals to a flexible cable so
  start the machine and released                                                       the operator can position the pedals
  immediately. It is found as an                                                       as desired ;
  additional pedal, beside the
  sewing pedal, or as an on/off pedal                                                ■ electric pedals embeded in anti-
  on automatic machines.                                                               fatigue rugs.

The sewing pedal                                                                     In addition:
                                                                                     ■ ensure that pedals adhere to floor
WIDTH OF PEDAL                                                                         surface so they will not move when
 When operators activate the sewing                                                    activated ;
pedal with two feet, the pedal should
                                                                                     ■ if possible, cover floor surface with
be wide enough to allow simultaneous
                                           LATERAL POSITION OF PEDALS                  shock-absorbing material to reduce
activation with both feet. When it is
                                                                                       leg fatigue or provide shoes with
not wide enough, operators have to         The pedal should be adjusted when
                                                                                       ergonomic soles.
push their knees together to activate      the operator is facing the work zone,
the pedal with their two feet, a           not necessarily in front of the needle.   To posture constraints is added the
movement causing discomfort in the         The pedal should be laterally             fatigue caused by working in an
hips and back. Wider pedals encourage      positioned so that the tight, leg and     upright position. There are several
better posture and allow proper            foot are in line.                         ways to reduce fatigue.
spacing between feet.
                                           FRONT/BACK POSITION OF PEDALS             If operators change machines
When operators activate the sewing                                                   regularly
                                           The front/back position of pedals
pedal with one foot, it is
                                           should be adjusted when the operator      When work conditions allow, provide a
recommended to install a footrest
                                           is sitting at the machine in a position   seat rest even if the operator uses it
beside the sewing pedal which should
                                           that provides a clear view of the work    only for short periods such as when
                                           at hand and does not impede               waiting for next batch of material.
■ the same height and at the same          movements. The front/back location of
  angle and front/back position as the     the pedal partly depends on the           If operators work continuously
  pedal ;                                  height of the chair.                      with one machine, including
■ wide enough ;                            The front/back adjustment is correct      for short periods of time (one
■ solidly fixed with a non-skid surface.   when:                                     hour or two)
                                           ■ thighs are approximately horizontal     Additional fatigue is caused by
                                             (with a horizontal seat) ;              working in an upright position while
                            WIDE PEDAL
                                           ■ knees are at an angle of                continuously remaining in the same
                                             approximately 120 degrees.              location. A higher chair should be
                                                                                     provided, including a second raised
                                                                                     position for pedals.


Additional pedal                          If operators work standing up,           BACKREST:
                                          applying pressure to pedals is an        ■ adjustable height, low enough to
A second, very thin pedal is sometimes
                                          important source of strain to the legs     support lower back of smaller
located beside the sewing pedal. This
                                          and back, especially if the operator       individuals ;
pedal activates the sewing machine’s
                                          always remains in the same location.
presser foot. It is recommended to                                                 ■ adjustable front/back position,
                                          Even on automatic machines, it is
eliminate the second pedal since                                                     advancing enough to support back
                                          much preferable to work in a sitting
operators have to lift and move their                                                of operators of all sizes ;
                                          position if the job design allows it.
foot to press it, causing additional                                               ■ relatively small size, to avoid
strain to the legs and hips. The second   If it is not possible to work sitting
                                                                                     blocking movements of the
pedal should be replaced with a foot      down, the pedals should be replaced
                                                                                     shoulder blades and elbows.
control integrated to the sewing          with other types of command
pedal.                                    mechanisms such as hand controls or      OTHER FEATURES:
                                          foot forward commands.                   ■ no rollers or blocking mechanism
If it is impossible to remove the
second pedal, position it:                                                           for roller feet, if applicable;

■ as close as possible to the sewing                                               ■ padded cover for seat and backrest.
  pedal to reduce the foot movement ;                                              Chair adjustment
■ at the same height, angle and
  front/back distance as the sewing                                                HEIGHT OF CHAIR
  pedal.                                                                           Adjustments should be made when
                                          ADJUSTMENT OF CHAIRS                     the operator is sitting at a normal
On/off pedals                                                                      distance from the sewing area and feet
                                          In order to maintain adequate body       are on the pedals. The chair height
On/off pedals are found on automatic      position when working in a sitting
machines such as lockstitch machines,                                              should be adjusted to make the seat
                                          position, operators should be provided   and thighs approximately horizontal. If
buttonhole and button machines, rivet     with the right chair. The chair should
machines and robot machines. They                                                  the chair is too high, the underside of
                                          be adjusted according to the size of     thighs will be pressed against the front
are generally very thin.                  the operator and the type of operation   edge of the chair; if too low, the body
If operators work sitting down,           performed.                               weight will be tilted backward, which
pressing the pedal with only one foot                                              will cause discomfort in the buttocks
will not lead to fatigue or discomfort    Features                                 area. If significant modifications to the
as long as the workstation design         Chairs for sewing machine operators      adjustment are made, the height of the
follows certain rules:                    must be of solid construction and        chair and the location of pedals will
■ place the pedal under the foot used     include the following features:          both need to be adjusted accordingly.
  to press on it, off center from the
  operator ;
                                          ■ easy and rapid height adjustment;
■ adjust the front/back position of the                                                   BACKREST
  pedal ;                                 ■ pivoting mechanism (particularly if     TOUCHES BACK OF
                                            operators need to turn sideways to            OPERATOR
■ place a footrest under the inactive       pick up and deposit material) ;
  foot to balance posture and prevent
  numbness in the inactive leg.           ■ smooth surface to avoid
                                            compressing underside of thighs
                                            and adequate width to
                                            accommodate larger persons ;
                                          ■ not to deep.

                                                                                   HEIGHT IS
                                                                                   ADJUSTED SO
                                                                                   THIGHS ARE

BACKREST ADJUSTMENT                       ■ select a surface with a matte finish    Space under the table
The backrest should be adjusted when        in a neutral shade.
                                                                                    The space under the sewing table
the operator is sitting at a normal       WORK LAMP                                 must be left uncluttered to leave
distance from the sewing area. The                                                  ample leg room. Clutter under the
                                          Adequate lighting of the work area
backrest is moved forward until it                                                  table can force the operator to adopt
                                          helps prevent visual fatigue and
comes in contact with the lower back                                                an uncomfortable body position at the
                                          promote proper body position. Lamps
of the operator. The operator should                                                workstation. Remove motors, control
                                          used for spot lighting should include
not need to back up in the chair in                                                 boxes, drawers and any other
                                          the following features:
order to lay against the backrest, and                                              equipment that may prevent proper
the backrest should not push the          ■ adjustable components to
                                                                                    positioning of the legs or obstruct
operator forward either. The backrest       accommodate different operators ;
                                                                                    pedal operation. For instance, chutes
should be positioned at the most          ■ swan neck or articulated arm to         for cuttings of material at overcasting
appropriate height for the operator.        direct light as needed ;                machines should not be located under
                                          ■ a lamp shade completely covering        the table: they can be placed higher
                                            the sides of light bulbs to avoid       up or replaced with aspirators.
ADJUSTMENT                                  dazzling ;
OF SEWING TABLES                                                                    Table adjustment
                                          ■ blocked air holes (on operators’ side
Most industrial sewing machines are         only), also to avoid dazzling ;         HEIGHT
mounted on sewing tables. Some types      ■ light bulbs with adequate wattage       Even if the operator remains the same,
of machines such as ordinary and            and low heat diffusion. The desired     the proper table height can vary
overcasting machines are built into the     light intensity varies according to     according to the work done and the
table while others are top-mounted,         factors such as the age of the          size of the material handled. Therefore
like most automatic machines and            operator, the level of precision of     the right height is not always at elbow
those with raised flatbed.                  the work being done and the             level. The proper height for the table
                                            quality of the work surface.            can be determined by observing the
Features                                                                            operator’s body position. If she needs
                                          Armrests                                  to bend forward to work, the table is
                                          Tables should be equipped with            probably too low. If she needs to raise
The table should be large enough to
                                          supports for the forearms except          her shoulders, the table is too high.
support material while sewing is being
                                          where operators work with hands           The table should be adjusted within
                                          close to the body, as is the case with    ± 2 inches of the operator's elbow.
Tables that are too small may:                                                      An operator working at a well-
                                          some automatic machines. In order to
■ cause bunching around the needle,       prevent back and shoulder injuries,       adjusted table will not need to lean
  or                                      proper forearm support should be          forward or raise her shoulders.
■ force operators to push and pull        provided in situations where operators    Remember that adjustments to the
  material during the sewing operation.   have to work with hands above and in      table should be done after the pedals
                                          front of them, or with elbows raised      and chair have been adjusted.
A work surface of adequate size gives
operators ample room to pick up and       sideways. If the table design does not
deposit material, and avoids the need     include arm support, consider adding
for potentially harmful movements to      armrests, which can be installed on the
lean sideways or backward.                table or the chair. They should be
                                          adjustable for height and for front to
WORK SURFACE                              back position so that arms and elbows
The surface should be completely          are supported without impeding the
smooth in order to make material          operator’s movements or preventing
handling easier.                          operators from bringing their chair
In order to prevent visual fatigue:       closer to the machine. If armrests
                                          cannot be installed, other solutions
■ avoid severe light contrasts on the     should be found.
  table, especially around the needle ;
■ remove any source of light
  reflection around the needle to                                                           ± 2 inches
  prevent dazzling;

TILT                                        HEIGHT
The sewing table can be tilted forward      Pick up and deposit areas should be
to encourage operators to refrain from      located at waist level so operators are     Various accessories can be added to
bending their heads. If tables with an      not required to bend down or reach          sewing machines in order to lower the
integrated tilting mechanism are            up too far. Remember that the location      work load and help reduce the risks of
unavailable, the same result can be         of handling areas should be                 injuries to the back or upper limbs
achieved with ordinary sewing tables        determined only once other                  (hands, wrists and elbows). However,
by raising the back legs. The angle of      components of the workstation have          some accessories such as manual
tilt is adjusted once the table is at the   been adjusted. The workstation design       hemming machines will cause
proper height. However, this                should place handling areas:                additional strain so all aspects of
adjustment may cause problem to the         ■ directly in front of operators ;          proposed attachments should be
lubrication system of certain models of                                                 carefully examined.
sewing machines.                            ■ approximately at waist level.

                                            Material bundles                            Accessories to facilitate work
                                                                                        Accessories such as pullers, automatic
MATERIAL PICK UP                            Handling material bundles from a
                                                                                        thread cutters and automatic feeders
AND DEPOSIT                                 sitting position puts a greater strain on
                                                                                        for material strips and elastic material
                                            the back and shoulders. Handling
                                                                                        can all make the operators’ work
Movements to pick up and deposit            operations should be performed
                                                                                        easier. They can also help eliminate
material can cause injuries to the back     standing up. If this is not possible, the
                                                                                        movements presenting a potential risk
and shoulders. Risks result from the        following measures should be taken:
                                                                                        of injury such as pulling and pushing
weight of material bundles and the          ■ reduce the size and weight of             material with the fingers, pressing
location of handling areas in relation        bundles to a minimum ;                    down on material with the fingers or
to the operator.
                                            ■ stack bundles properly ;                  repeatedly stretching the arms
There are several ways to reduce risks                                                  forward (to cut thread by hand).
of injuries:                                ■ use solid ties that are easy to put on
                                              and remove.
■ design pick up and deposit areas
  adequately;                               If material handling areas are located
                                            at waist level, prepare smaller bundles
■ pack material in lighter bundles;         of material. Place larger and heavier
■ install mechanical aids where             bundles on work surfaces that can be
  possible.                                 lowered or raised by the operator.
                                            Mechanical aids to facilitate material
Material handling areas
                                            handling such as automatic stackers or
POSITION                                    robot arms are available. They can help
Operators should be able to pick up         reduce back and shoulder strain.
and deposit material directly in front      Handling aids should be installed only
of them, never behind, to avoid             if no other ways to eliminate risks have
potential back and shoulder injuries.       been found.
Handling areas may be located:
■ on the sewing table ;
■ on shelves installed over the table ;
■ on a retractable shelf over the
  operator’s knees ;
■ on a retractable stalk.
If material handling areas cannot be
positioned in front of the operator,
they can be positioned slightly to the
side as long as operators do not have
to make movements that may lead to
shoulder injury. Material is generally
picked up and deposited on tables,
carts, bins, stands or conveyors.
                                       The tools most widely used by sewing
                                       machine operators are scissors and
                                       thread cutters. Using these tools can
                                       lead to hand and wrist strain. There is
                                       also a danger caused by dropping
                                       scissors.                                 The Préventex newsletter
       AUTOMATIC                                                                 is published by
    THREAD CUTTER                                                                Préventex – Association paritaire du
                                       When using scissors or thread             textile
                                       cutters, avoid:                           2035, Victoria avenue, suite 203
                                       ■ making strenuous movements with         Saint-Lambert QC J4S 1H1
                                                                                 Telephone : (450) 671-6925
                                         the wrists (flexing or bending) ;       Fax : (450) 671-9267
                                       ■ applying excessive pressure on          e-mail :
                                         fingers or palm ;
                                                                                 General manager and
                                       ■ rubbing the skin on rough or sharp      newsletter editor
                                         parts of the tools.                     Jean-Marc Champoux
                                                                                 Co-chairman (Employers)
                                       To avoid strenuous                        Jacques Hamel
                                                                                 Cavalier Textiles inc.
                    AUTOMATIC FEEDER   movements of the wrists:                  Co-chairman (Unions)
                                       ■ choose scissors or cutters designed     Pierre-Jean Olivier
                                         to keep wrists straight during use ;
                                       ■ perform cutting operations in an        Lise Laplante
                                         area with enough room to allow          Copy editor
                                         work with straight wrists.              Pierre Bouchard
                                                                                 Indico Communication
                                       To avoid excessive pressure               Translation
                                                                                 Paule Champoux-Blair
                                       on hands:                                 Graphic design
                                       ■ adapt the size of the handle to the     Anne Brissette Graphiste
                                         size of the operator’s hand ;           Printing
                                                                                 Imprimerie For inc.
                                       ■ provide a choice of left-handed and     Préventex, its managers and personnel, as well
                                         right-handed scissors ;                 as authors of articles published in the
                                                                                 Préventex newsletter make no guarantee as to
                                       ■ keep tools sharp.                       the accuracy of the information contained
                                                                                 therein nor as to the pertinent efficiency that
                                       To avoid injuries to the skin:            may be inferred from this information, and
                                                                                 therefore accept no responsibility. The
                                       ■ choose models with a rounded,           information contained in the newsletter
                                         smooth design.                          should not be considered professional advice.
                                                                                 Mention of products or services by advertisers
                                       Finally, in order to avoid dropping       or in articles does not constitute an
                                       scissors, secure them to the table with   endorsement or recommendation of same.
                                       a solid elastic band or with Velcro.      The Préventex newsletter is distributed free of
                                                                                 charge to members of the textile and knitting
                                                                                 industries in the Province of Québec. Its
                                                                                 contents may be duplicate provided prior
                                                                                 authorisation is obtained from Préventex and
                                                                                 the source is mentioned.
                                                                                 Legal deposit :
                                                                                 September 1st, 1994
                                                                                 ISSN 0825-4230
                                                                                 Printing: 2500 copies