Note: Descriptions are shown in the official language in which they were submitted.
W0 95/09134 2 ~ 7 ~ 94,00901
SAFEl~Y WINDOW
..
This invention relates to a safety window which may be used
as display window in a showcase or as bullet-proof window in a bank
or elsewhere where security requirçm~nt~ are high.
In order to assess the capacity of safety windows to withstand
5 merh~nic~l working, the Swedish Theft-Prevention Association tests
safety windows according to Swedish Standards SS 3492, 2nd Ed.,
Test with Hand Tools, Sec. 5, to provide a basis for a spe~ific~tio~ of
the requirements, Sec. 4.1, 4th paragraph. In the test, use is made of
a sledge, a chisel retainer, a pointed chisel, a drilling m~ehine as
10 well as other tools stated in the standard specific~tion, the purpose
being to make a standard hole measuring 100 x 100 mm. When it
comes to testing bullet proofness, there are no such standard speci-
fications. Huw~v~r, a common method consists in firing at the safety
windows from a distance of 10 m with powerful firearms, such as an
15 autom~tiC carbine of Ak4 type (7.62 mm live cartridge 10, muzzle
velocity 820 m/sec.) or Ak5 type (5.56 mm live cartridge 5, muzzle
velocity 930 m/sec). In order that a safety window should pass the
hand tool test, it has to take at least 10 min. to make a standard hole
measuring 100 x 100 mm therein. As to the bullet-proofness require-
20 ment, the bullets from such powerful Clea.llls as are mentioned aboveshould not be able to penetrate the safety window.
One widely-used bullet-proof window is made up of five lami-
nated glass panels (SE-B-437,729) or eight l~minate~l glass panels
(VEGLA of the make St Gobain), such that the whole assembly has a
25 thi~kness of 39 rnm. Although such safety windows are able to with-
stand the fire from powerful firearms, they have poor resistance to
working by hand tools (often 3.5 min. in tests of the VEGLA window in
accordance with the above standard spe~ifi~tion). The rather thick
VEGLA v~rindow in ~lrlition has the disadvantage of a green-toned
30 appearance due to the considerable thi~-kness of the glass. The greater
the number of glass panels or the greater the total thiçkness, the
greener the safety window.
wo95109134 2 1 7 2 9 7 9 ~ h54~00901
In order to master the problem of green toning and other optical
errors, such as Newton's -rings, in safey windows composed of several
glass sheets that have been joined together, SE-B-358,466 provides
safety windows which are designed as glass sheet units made up of
5 a number of glass and polycarbonate sheets. Thus, the SE specifica-
tion describes windows in which glass and polycarbonate sheets are
arranged in alternate f~hion, ei~er in direct contact, with or without
a binder, or at a distance from one another. Although such a window
is able to withstand a certain degree of firing, it has an c~ elllely low
10 resistance to mech~nic~l working by hand tools. Thus, the outer
panes or sheets, which consist of a single glass layer, are easily
crushed, e.g. with the aid of a sledge, and it is then fairly easy to
make holes in the centrally located polycarbonate sheets, which have
low resistance to cutting and drilling. In addition, there is a consider-
15 able risk of condens~tion in the glass sheet unit when the polycarbo-
nate sheets are separated and exposed to air. Naturally, conden.~tin~
has an adverse effect on the optical ~JlO~Cl ~ies of the s-~semh1y.
Thus, none of the prior-art constructions combines good optical
properties, good resistance to mech~nir~l working by hand tools and
20 good resistance to effective fire from heavy firearms. Naturally, there
is a ~lern~n~l for such a safety window, since the one type of attack
does not exclude the other. In banks, for instance, the need for such
higher security has, regrettably enough, increased. In addition, the
safety windows used in banks and the like have to exhibit good optical
25 ~ cl Lies and render shapes and also colours as naturally as pos-
sible.
One object of the invention is, thelerolc, to provide a safety win-
dow which not only meets the somewhat contradictory requirements
on high resistance to merh~nic~1 working by hand tools, high resis-
30 tance to firing also with heavy firearms, and minimum optical distor-
tion or undesirable colour toning p1cve1lting a natural colour rendi-
- tion.
This and other objects of the invention are met by a safety win-
dow as ~çfinr~ in appended claim l Especially preferred embodiments .
35 of the invention are stated in the subrl~im~:.
To put it briefly, the inventive solution to the problems withprior-art safety windows is based on the insight that the safety win-
WO95/09l34 2 1 7 ~ q 7 q PCT/SE94/00901
dow should be formed of at least two spaced-apart successive lami-
nated glass sheet panels, each comprising at least two glass sheets
and three polycarbonate sheets, which are so l~min~te~l with one
another that the two outer surfaces of each l~min~ted glass panel are
formed of glass sheets.
Apart from offering much better protection ~gpin~t burglary
with the aid of hand tools and much better protection ~inst firing
also with heavy firearms, the safety window according to the invention
has the considerable advantage of a lower total weight than many
prior-art bullet-proof windows, especially those made of glass material
only.
The invention will now be described in more detail with refe-
rence to the aCco-mr~nying drawing, which illustrates an embodiment
of a safety window according to the invention and more precisely is a
sectional view of an edge portion of the window and its ~tt~chmerlt
The illustrated embodiment of a safety window is designed as
a glass sheet unit 10, in which two l~min~ted glass panels 11, 12 are
spaced apart by a circumferential spacer 14, e.g. of aluminium, so
that there is formed an air gap 13. The spacer 14 may be composed of
hollow-section strips and contain a drying agent, especially if the
glass sheet unit 10 is designed as a thermopane assembly, i.e. if the
space between the two l~min~te~l glass panels 11, 12 is hermetically
sealed. Each of the l~minaterl glass panels 11, 12 comprises several
glass and polycarbonate sheets.
In this embodiment, the outer l~min~t~d glass panel 11 is form-
ed of two external layers 15, 16 of glass material and three interme-
diate layers 17, 18, 19 of polycarhorlate material.
The different sheets or layers are joined vrith one another over
their entire mutually facing sides. To this end, epoxy Arlhesive may
be used. Hc wt:vel, use is pl~felably made of a thin polyurethane film
which, by low heating of the super~osed glass and polycarbonate
sheets, is anchored in the sheets t~ ~ind them together. Polyurethane
film has the advantage of acting as a dampening cushion between
adjoining sheets and thus contributes to increase the resistance to
mech~ni~l wu~ g and firing. Also other types of binder layers, e.g.
of polyvinyl butyrate, may be used. How~vel, this type of binder layer
provides slightly weaker adhesion between the sheets than do poly-
2~ 7297~
wo 95/09l34 ~ hs4/oosol
urethane films and epoxy layers but is, for many purposes, fully satis-
factory.
In the illustrated embo~imPnt, a binder layer 20 of polyvinyl
butyrate or polyurethane is arranged between the outer glass sheet
5 15 and the intermediate polycarbonate sheet 17 closest thereto.
The other sheets are l~min~tefl with each other by layers of epoxy
~lhes;ve.
The inner l~min~te-l glass panel 12 consists of three glass
sheets 21, 22, 23 and three polycarbonate sheets 24, 25, 26. All these
10 sheets are l~minP~t~r1 with each other by some sllit~ble adhesive, espe-
cially an epoxy adhesive. In the illustrated embodiment, the inner
l~min~ted glass panel 12 is not provided with any dampening layer.
Should one, how~vel, vwish to increase the resistance to impacts and
bullets, a dampening layer equivalent to the binder layer 20 may be
15 inserted in the inner l~min~te-l glass panel 12 as well.
This design of the safety window results in very high resistance
to firing and me~h~nic~l wulhillg, e.g. when there is an ~ ,ted
burglary, since the air gap 13 between the t~,vo l~min~te~l glass panels
11, 12 m~k~s it much more difficult to make holes in the safety win-
20 dow with the aid of cutting tools. The air gap further enhances thec~r~city of the safety v~lindow to resist firing, since any bullets passing
- through the first or outer l~min~terl glass panel 11 will be deformed,
thus having lost part of their penetration power. Thus, the air gap 13
renders penetration into the inner l~min~ted glass panel 12 more
25 difficult.
The safety window can be ~tt~rhe~l in many ways. The dlaw~lg
shows one advantageous ~tt~chment arrangement. Here, a mounting
section 27 of standard steel or stainless steel is fixed in a surrolmrling
bllikling structure 28. A plate 29 of high-strength steel is fixed at the
30 back of the mounting section and serves as protection against the
penetration of bullets.
In the mounting section 27, there is provided a torsionally rigid
frame section 30, which is designe~l as an extruded sectional strip of
steel, hardened alllminillm or some other light-metal material. The
35 illustrated design of the irame section 30 having an inwardly-direct-
ed cl~mring flange 31 results in high torsional rigidity. The safety
window will then be clamped between the el~mring flange 31 and a
WO95109134 2 1 i~919 ~ 54~00901 .
frame 32 arranged on the outside. In the illustrated embodiment, the
frame 32 consists of an extruded metal section 33, e.g. of aluminium
or some other light-metal material, and at least one frame strip mem-
ber 34 of high-strength material, ~rererably high-strength steel mate-
5 rial, inserted in the metal section. The corners of the frame have beenreinforced by there welding together the frame strip members 34 to
angles, mAkin~ more difficult any Attempts to break them away. The
joints between the frame strip members 34 are placed at the centre
of the vertical or horizontal side of the frame 32 in order to facilitate
10 mounting of the metal section 33. The frame strip member 34 is
inserted in the metal section 33 with a view to bridging the joint, thus
increasing the strength of the frame 32. In the illustrated embodi-
ment, the metal section 33 is a C-section having an undercut groove
35 for accommodating the frame strip member 34, fixing screws 36
15 being inserted through holes in the frame section 30 and the mount-
ing section 27 and sc~ d into threaded holes in the frame strip
member 34. In order to provide thermal insulation and counteract the
emergence of cold bridges round the safety window, two extruded
decoration strips 37 and 38 of light metal are AttA~hed to the frame
20 section 30, and an inslllAting material 39 is provided bet~veen the
decoration strips and the frame section. In customary fashion, layers
40, 41 of jointing mastic and a cover strip 42 have been provided.
A sticky seAling material 43 is, in collv~lltional m~nner, provid-
ed between the safety window and, respectively, the clamping flange
25 31 and the frame 32.
DESCRIPI`ION OF AN EMBODIMENT
The safety window of this embodiment is of the type shown in
the drawing and thus includes t~,vo ~AminAted glass panels 11, 12.
Counting from the outside (from the right in the drawing), the
30 outer or front l~minAted glass pan-l 11 consists of one 4-mm-thick
float glass sheet, one 1.5-mm-thick binder layer of polyvinyl butyrate,
three 4-mm-thick polycarbonate sheets, and one 4-mm-thick float
glass sheet. The polycarbonate sheets and the inner float glass sheet
are lAminAte~l with one another by m~An~ of a thin layer of epoxy
35 Atlhesive, while the polyvinyl-butyrate layer serves as binder layer
between the outer float glass sheet and the outer polycarbonate sheet.
- 21 7297~
WO 95/09134 1~ ih54/00901
With such a construction, the outer l~min~ted glass panel 11 has a
thickness of 25 mm.
Counting from the outside (from the right in the drawing), the
inner or rear l~min~ted glass panel 12 consists of one 4-mm-thick
5 float glass sheet, one 8-mm-thick polycarbonate sheet, one 6-mm-
thick polycarborl~t~ sheet, one 4-mm-thick float glass sheet, one
6-mm-thick polycarbonate sheet, and one 4-mm-thick float glass
sheet. The dirrc;-el-t sheets are l~min~te-l with one another by me~ns
of a thin layer of epoxy adhesive. With such a construction, the inner
1~minatetl glass panel 12 has a thic-kness of 38 mm.
Be~w~-- the two l~min~qtetl glass panels 11, 12, there is an air
gap of 15 mm, which is hermetically sealed by means of a circumfe-
rential strip of aluminium section, which is open inwards towards the
air gap and contains a drying agent. The entire safety window conse-
15 quently has a thickness of about 78 mm.
The test shootings accounted for below involved safety windowsof the above construction, which measured 60 x 60 cm.
In the test shootings, the safety windows were placed at a 90
angle to the firing line. The shot was st~n~lin~ 10 m from the safety
20 window and fired 3 shots. The distance between the points of impact
was about 15 cm.
TEST SHOOTING A
Three shots (7.62 mm live cartridge 10, muzzle velocity
820 m/sec.) were fired vwith an ~lltom~tic carbine Ak4 at the 25-mm-
25 thick l~mins~te-l glass panel of the safety window. No bullet fr~ m~ntS
penetrated to the back of the safety window. All the bullets stopped in
the rear 38-mm-thick l~min~te-l glass panel, a~ .x;~ tely in the
rear 6-mm-thick polycarbonate sheet. The entry holes in the outer
- 25-mm-thick l~min~ted glass panel "self-healed", and a nail having
30 a diameter of 2 mm could not be driven into the entry holes by hand.
The rear glass sheet in the 38-mm-thick l~min~te~l glass panel of the
safety vwindow became mealy over a surface that had a diameter of
about 1 dm.
Test shooting after turning the safety window, such that the
35 38-mm-thick l~min~te~l glass panel faced the shot, yielded the same
results.
21 7297~
WO gS/09134 ~ 54/ooso
TEST SHOOTING B
Test shooting A was repeated, but this time the weapon was an
automatic carbine AkS and the ammunition consisted of 5.56 mm live
cartridge 5 having a muzzle velocity of 930 m/sec.
Neither in this case did any bullet fragments penetrate to the
back of the safety window. All the bullets stopped in the rear polycar-
bonate sheet. The entry holes in the outer 25-mm-thick l~min~ted
glass panel "self-he~1erl", and a nail having a diameter of 2 mm could
not be driven into the entry holes by hand. The rear glass sheet in
the 38-mm-thick l~min~ted glass panel of the safety window became
mealy over a surface that had a diameter of about 1 dm.
Test shooting after turning the safety window, such that the
38-mm-thick l~min~terl glass panel faced the shot, yielded the same
result.
TEST SHOOTING C
Test shooting A was repeated, but this time the weapon was
a rifle of the make Valb~ and the ammunition consisted of
Cal. 338 Winchester Magnum Lead point 16.2 g having a muzzle
velocity of 835 m/sec.
This test shooting yielded the same results as did test shootings
A and B, e~cc~ g that the entry hole in the first 25-mm-thick
l~minatçd glass panel had a diameter of 6 mm. The rear glass sheet
in the 38-mm-thick l~min~te~ glass panel of the safety window
became mealy over a surface that had a diameter of about 2 dm.
Test shooting after turning the safety window, such that the
38-mm-thick l~minPlted glass panel faced the shot, yielded the same
results.
TEST SHOOTING D
Test shooting A was repeated, but this time the weapon was
a rifle of the make Varberger and the am~unition consisted of Cal.
375 H & H Magnum Lead point 19.54 g h~ving a muzzle velocity of
835 m/sec.
This test shooting yielded the same results as did test shootings
A and B, ~ ;e~ g that the entry hole in the first 25-mm-thick
l~min~te-l glass panel had a diameter of 6 mm. The rear glass sheet in
the 38-mm-thick l~min~ted glass panel of the safety vwindow became
mealy over a surface that had a diameter of about 2 dm.
WO g5/09134 2 1 7 2 9 7 ~ 54/ooso~
Test shooting after turning the safety window, such that the
38-mm-thick lslmin~te~ glass panel faced the shot, yielded the sarne
results.
STANDARD-HOLE-CUTTING TESTS INVOLVING HAND TOOLS
These tests were carried out by the Swedish Theft-Prevention `
Asso~i~tion according to Swedish Standards SS 3492, 2nd Ed., Test
with Hand Tools, Sec. 5, to provide a basis for a specific~tio~ of the
requirements, Sec. 4.1, 4th paragraph. In order for a safety window to
make it to the highest safety class, it has to take more than 10 min.
to make a standard hole measuring 100 x 100 mm in the glass panel.
In the tests, two experienced ~ el Ls were allowed to operate after
an unlimited time of prepar~tiorl~q. The required resistance time of
at least 10 min. applies to every subtest and is not a total time for a
whole glass panel. This me~nq that one may test several areas or
points where weaknesses may be found, such as the centre, the outer
edges or the corners of the glass panel, as well as the ~tt~chment of
the glass panel. Thus, the resistance time for each subtest must be at
least 10 min.
ATTEMPTED BURGLARY A
The safety window used was of the same construction as the
windows subjected to the test shootings.
In this ~ttemrted burglary, one tried to make a standard hole
measuring 100 x 100 mm. The mode of procedure and the results ap-
pear from Table 1 below. With this procedure, it took 15 min. 38 sec.
of working before the standard hole gauge could be inserted through
the hole, which measured about 105 x 120 mm.
ATTEMPI`ED BURGLARY B
The safety window used was of the same construction as the
windows subjected to the trial shootings and ~ 1 le~ .Led burglary A.
In ~1 l e. . ~ ~ted burglary B, one used a slightly diLrel ellt approach
when m~king the standard hole measuring 100 x 100 mm. The mode
of procedure and the results appear from Table 2 below. With this
procedure, it took 15 min. 7 sec. of working until the standard hole
gauge could be inserted through the hole, which measured about
120 x 100 mm.
wo 95/09l34 2 1 7 2 9 7 9 Pcr/sEg4loogQl
COMPARISON - ATTEMPTED BURGLARY C
This comparative test involved a commercially available safety
window composed of eight l~min~ted flat glass sheets and having a
total thickness of 39 mm (the make VEGLA from St Gobain). The
5 mode of procedure and the results appear from Table 3 below. The cut
hole measured about 130 x 130 mm. As appears from the results, it
took much less than 10 min. to make the standard hole.
WO 95109134 2 1 7 2 9 7 9 PCT/SE94100901
TABLE 1
Attack Tool Total time '`
Crushing of glass outer layer Sledge, pointed chisel, 40 sec.
chisd
Drilling through outer layer Dri31ing mArhin~, drill ~ 10 1 min. 26 sec.
Crushing of glass inner layer Sledge, pointed chisel, 2 min. 50 sec.
chisel retainer
Drilling through both glasses Drilling ms~hine, drill ~ 10 7 min. 25 sec.
and milling b~ L .~ ~.1 the
holes
Breaking-away of outer layer Jemmy 7 min. 40 sec.
Further drilling Drilling ms~-~hin~8 min. 15 sec.
Breaking Jemmy 8 min~ 25 sec.
.Sm~hin~ tuw~-ls inner Sledge 8 min. 40 sec.
layer
Drilling towards inner layer Drilling ms:lrhin-~, drill ~ lO 9 mm. 55 sec.
.Sms~hin~ Luw~:uds inner Sledge lO min. 15 sec.
layer
Further drilling Drilling marhinP, drill ~ 10 11 min. 3 sec.
Crushing of glass mner Sledge, pointed chisel,11 min. 55 sec.
layer chisel retainer
Drilling towards inner Drilling ms:lrhin~, drill ~ lO 12 min. 45 sec.
layer
Cutting bcLwccll holes in Sledge, pipe wrench,12 min. 55 sec.
inner layer slot chisel
Drilling t.. w~ds inner Drilling mArhin~, drill ~ 10
layer 13 min. 20 sec.
Cutting bcL~ .l holes in Hand sledge, pipe wrench,13 min. 55 sec.
inner layer slot chisel
Drilling towards inner Drilling m~rhinP, drill ~ lO 14 min. 45 sec.
layer
S.~.a!:h;... f~ Lu.. ~-ls Sledge 15 min. 38 sec.inner layer
WO 95/09134 2 1 7 2 q 7 9 1~ h54loo9ol .
TABLE 2
Attack Tool Total time
Crushing of glass outer layerSledge, pointed chisel, 25 sec.
chisel ,~l~i..~.
Drilling through outer layerDrilling m~rhinP, drill ~ lO 2 _in. 55 sec.
23 holes
Crushing of glass inner layerSledge, pointed chisel, 3 min. 41 sec.
chisel lC~illC~
Drilling through inner layerDrilling m~chinr, dr;ll ~ 10 7 min. 5 sec.
23 holes
Cutting beL~ m holes in Sledge, slot chisel,7 min. 25 sec.
outer layer pipe wrench
Milling belwee l holes in Drilling m~rhinP, drill ~ lO g m in. 15 sec.
outer layer
Cutting bc:L~ .- holes in Sledge, axe10 _in lO sec.
outer layer
Bre~king-away of outer layer Jemmy 10 min 32 sec.
Cutting belweell holes Sledge, axe12 min 22 sec.
Further drilling in inner Drilling m~rhinP, drill ~ lO 13 min 5 sec.
layer
Cutting belwèell holes in Sledge, slot chisel,13 in. 37 sec
inner layer pipe wrench
Cutting between holes in Sledge, axe14 min. 12 sec.
inner layer
Further drilling in inner Drilling m~rhinP, drill ~ lO 14 _in. 5 sec.
layer
.~mP~.~hin~ of inner layer Sledge 15 min. 7 sec.
21 72979
WO g5/09134 ~ 54,0090
T~BLE 3
Attack Tool Total time
Cutting of three sides of Sledge, chisel ~el~i,~e., 2 min. 15 sec.
door po~nted chisel
Drilling and milling Drilling marhinr, drill ~ 10 3 min. 20 sec.
Sma~:hinf~ of door Sledge 3 min. 31 sec.
- COMPARISON - ATTEMPI`ED BURGLARY D
This test involved a lAmin~terl glass panel of the same construc-
tion as the thick, rear l~min~tell glass panel in the safety window
according to the invention. The l~min~terl glass panel tested thus had
the same structure as the rear panel 12 in the embodiment described
above.
The mode of procedure and the results appear from Table 4
below. The standard hole gauge measuring 100 x 100 mm could be
inserted through the hole after 7 min. and 12 sec.
TABLE 4
Attack Tool Totl time
Crushing of glass before Sledge, chisel retainer, 20 sec.
drilling pointed chisel
DrilliTlg through plastic Drilling marhinf, drill ~ 10 2 min. 25 sec.
layer
Crushingofglass Sledge, chisel l~ , 3 min. 25 sec.
pointed chisel
Drilling through plastic Drilling marhinr, drill ~ 10 5 min. 50 sec.
- ~layer
,~ma~hin~ al ~ t at Sledge 6 mirl.
opening made
Milling beL~ ,. holes Drilling marhin~, drill ~ 13 6 min. 25 sec.
;~ma~1~inE of opening Sledge 7 min 12 sec.
