U.S. patent application number 14/299248 was filed with the patent office on 2015-01-01 for wristwatch with sacrificial pin.
This patent application is currently assigned to ETA SA MANUFACTURE HORLOG RE SUISSE. The applicant listed for this patent is ETA SA MANUFACTURE HORLOG RE SUISSE. Invention is credited to Thierry ALTENHOVEN, Raphael BALMER, Martin JUFER, Stephane LEONI, Damien SCHMUTZ.
Application Number | 20150003217 14/299248 |
Document ID | / |
Family ID | 48745731 |
Filed Date | 2015-01-01 |
United States Patent
Application |
20150003217 |
Kind Code |
A1 |
LEONI; Stephane ; et
al. |
January 1, 2015 |
WRISTWATCH WITH SACRIFICIAL PIN
Abstract
Device for fastening a bracelet strand to a case of a watch. The
device includes at least one fastening element allowing this
bracelet strand to be detached from this case when this fastening
element is subjected to a predetermined force or moment. Wristwatch
including a case and at least one bracelet strand pivotally hinged
about a shoulder of a pin forming such a device. This pin is a
sacrificial pin which includes, on this shoulder, at least one area
of mechanical resistance lower than the lowest mechanical
resistance of this case and than the lowest mechanical resistance
of this bracelet strand.
Inventors: |
LEONI; Stephane;
(Courtelary, CH) ; ALTENHOVEN; Thierry; (Delemont,
CH) ; BALMER; Raphael; (Courendlin, CH) ;
JUFER; Martin; (Melchnau, CH) ; SCHMUTZ; Damien;
(La Neuveville, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ETA SA MANUFACTURE HORLOG RE SUISSE |
Grenchen |
|
CH |
|
|
Assignee: |
ETA SA MANUFACTURE HORLOG RE
SUISSE
Grenchen
CH
|
Family ID: |
48745731 |
Appl. No.: |
14/299248 |
Filed: |
June 9, 2014 |
Current U.S.
Class: |
368/282 |
Current CPC
Class: |
A44C 5/18 20130101; G04B
37/1486 20130101; A44C 5/14 20130101 |
Class at
Publication: |
368/282 |
International
Class: |
A44C 5/18 20060101
A44C005/18 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 27, 2013 |
EP |
13174090.4 |
Claims
1. A device for fastening a bracelet strand to a case of a watch,
wherein the device includes at least one fastening element allowing
said bracelet strand to be detached from said case when said
fastening element is subjected to a predetermined force or
moment.
2. The device according to claim 1, wherein said fastening element
includes at least one watchmaker's pin including at least one
shoulder extending in an axial direction, in that said pin is a
sacrificial pin and includes, on said shoulder, at least one area
of mechanical resistance lower than 45 MPa.
3. The device according to claim 1, wherein said fastening element
includes at least one end link, and in that said end link is a
flexible link including a first end to be secured to said case and
a second end to be secured to said bracelet strand, and including
means of absorbing torsion torque so that the reduction factor
between a torsion torque applied to said second end and the
resulting torsion torque at said first end is higher than a factor
10.
4. The device according to claim 2, wherein said fastening element
includes at least one end link, and in that said end link is a
flexible link including a first end to be secured to said case and
a second end to be secured to said bracelet strand, and including
means of absorbing torsion torque so that the reduction factor
between a torsion torque applied to said second end and the
resulting torsion torque at said first end is higher than a factor
10, and wherein said end link includes, at said first end thereof,
a said pin.
5. A wristwatch including a case and at least one bracelet strand
secured to each other, wherein the connection between said bracelet
strand and said case includes a fastening element according to
claim 1.
6. The wristwatch according to claim 5, wherein said case and said
bracelet strand are pivotally hinged about a shoulder of a pin
which forms said fastening device and which is a sacrificial pin
which includes, on said shoulder, at least one area of mechanical
resistance lower than the lowest mechanical resistance of said case
and than the lowest mechanical resistance of said bracelet
strand.
7. The wristwatch according to claim 6, wherein said case includes
at least a first clevis mount with a first hole along a first axis,
and in that said at least one bracelet strand includes at least a
second clevis mount with a second hole along a second axis and is
fastened to said at least one first clevis mount of said case by
said sacrificial pin wherein said at least one shoulder is
dimensioned to pass into said first hole and into said second hole
to pivotally guide and secure said bracelet strand and said case,
and in that the resistance of said pin to traction, shearing,
torsion, and fatigue is lower than the lowest respective resistance
of said case and of said at least one bracelet strand.
8. The wristwatch according to claim 7, wherein each said first
clevis mount includes at least a first lateral face which is radial
relative to said first axis, in that each said second clevis mount
includes at least a second lateral face which is radial relative to
said second axis, and in that, when said at least one bracelet
strand is in the assembled position hinged on said case via said
pin, said first clevis mounts are alternated with said second
clevis mounts defining interface areas in each of which a said
first lateral face faces a said second lateral face, with an axial
play comprised between 0.000 and 0.060 mm.
9. The wristwatch according to claim 8, wherein at least one said
area of low resistance of said pin is situated, when said at least
one bracelet strand is in the assembled position hinged on said
case via said pin, perpendicular to a said interface area.
10. The wristwatch according to claim 7, wherein at least one said
first clevis mount is bushed with a metal insert including said
first hole thereof.
11. The wristwatch according to claim 7, wherein at least one said
second clevis mount is bushed with a metal insert including said
first hole thereof.
12. The wristwatch according to claim 6, wherein said peripheral
shoulder of said pin includes, over the length thereof, first areas
of higher resistance alternating with second areas of lower
resistance.
13. The wristwatch according to claim 12, wherein said first areas
of higher resistance are made of rigid metal material or hard
plastic material, and in that said second areas of lower resistance
are made of flexible plastic material or elastomer overmoulded on
first areas of higher resistance.
14. The wristwatch according to claim 12, wherein at least one area
of low resistance is formed by a said second area of lower
resistance.
15. The wristwatch according to claim 12, wherein at least one area
of low resistance is formed by the interface area between a said
second area of lower resistance and a said first area.
16. The wristwatch according to claim 7, wherein said peripheral
shoulder of said pin includes, over the length thereof, first areas
of higher resistance alternating with second areas of lower
resistance, and wherein each said first area of higher resistance
faces a said first hole.
17. The wristwatch according to claim 7, wherein said peripheral
shoulder of said pin includes, over the length thereof, first areas
of higher resistance alternating with second areas of lower
resistance, and wherein each said first area of higher resistance
faces a said second hole.
18. The wristwatch according to claim 6, wherein said pin includes
at least one notch in a said area of low resistance.
19. The wristwatch according to claim 6, wherein said pin is made
of a plastic material chosen from among polyoxymethylene (POM),
polytetrafluorethylene (PTFE) filled with glass fibre,
poly(p-phenylsulfide) (PPS) filled with glass fibre,
polyamide-imide (PAI), polyether ether ketone (PEEK), or even
polybenzimidazole (PBI).
Description
[0001] This application claims priority from European Patent
Application No. 13174090.4 filed Jun. 27, 2013, the entire
disclosure of which is hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The invention concerns a device for attaching a bracelet or
wristlet strand to a watch case.
[0003] The invention further concerns a wristwatch including a case
and at least one bracelet strand secured to each other.
[0004] The invention concerns the field of horology and jewellery,
and more precisely the field of assembled units, such as
wristwatches, including several components assembled to each other
by a hinged connection.
BACKGROUND OF THE INVENTION
[0005] The area of assembly of the bracelet or wristlet of a watch
or piece of jewellery to a case or to a solid component is always
an area where the stresses applied by the user to the bracelet, as
a result of his movements, are concentrated. The concentration of
forces or of fatigue may cause a deterioration or even breakage of
certain components, particularly the horns of the case, or even the
watch case itself, particularly when it is made of a plastic
material or fragile material. The cost of repair or replacement is
high, and damaging for the manufacturer's image.
[0006] EP Patent Application No 0246449A1, in the name of ETA,
discloses a bracelet whose ends are retained in slots in a watch
case by pins partially engaged in grooves each arranged in a face
of the slots. There is no detachment of the bracelet from the case
when the fastening is subjected to a predetermined force.
[0007] U.S. patent application No. 5,235,567A, in the name of
GODWIN, discloses a watch bracelet whose ends are folded over
themselves and can be immobilised by transverse tubes that form
pins and cooperate with transverse holes in the bracelet strands,
these tubes being immobilised by a metal wire forming a spring.
[0008] FR Patent Application No 2323350A1 in the name of NORMAND
discloses a similar system to the above with a linking member with
two studs forming pins to cooperate with the horns, connected by
elastic material.
SUMMARY OF THE INVENTION
[0009] The invention proposes to overcome the problems of the prior
art by making it possible to disassemble a wristwatch unit prior to
breakage of the case and/or the bracelet. The invention proposes to
insert a low cost sacrificial component, which plays the part of a
"fuse" and protects the main components and the most expensive
components.
[0010] To this end, the invention concerns a device for fastening a
bracelet strand to a watch case, characterized in that it includes
at least one fastening element allowing said bracelet strand to be
detached from said case when said fastening element is subjected to
a predetermined force or moment.
[0011] According to a feature of the invention, said fastening
element includes at least one watchmaker's pin including at least
one shoulder extending in an axial direction, said pin is a
sacrificial pin and includes, on said shoulder, at least one area
of mechanical resistance lower than 45 MPa.
[0012] The invention also concerns a wristwatch including a case
and at least one bracelet strand secured to each other,
characterized in that the connection between said bracelet strand
and said case includes a fastening element of this type.
[0013] According to a feature of the invention, said case and said
bracelet strand are pivotally hinged about a shoulder of a pin
which forms said fastening element and which is a sacrificial pin
which includes, on said shoulder, at least one area of mechanical
resistance lower than the lowest mechanical resistance of said case
and than the lowest mechanical resistance of said bracelet
strand.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Other features and advantages of the invention will appear
upon reading the following detailed description, with reference to
the annexed drawings, in which:
[0015] FIG. 1 shows a schematic perspective view of a detail of a
wristwatch, with the joint between the watch case and a bracelet
strand with a fastening element according to the invention.
[0016] FIG. 2 shows a schematic cross-section through the axis of a
sacrificial pin according to the invention forming this fastening
element in a first variant, and fitted into a series of holes
comprised in alternate clevis mounts in the case and the bracelet
strand, in a first embodiment wherein the sacrificial pin includes
notches forming break-off points.
[0017] FIG. 3 shows a similar schematic view to FIG. 2 of a second
embodiment wherein the pin includes alternate rigid elements and
flexible overmoulded elements.
[0018] FIG. 4 shows a similar schematic view to FIG. 2 of a third
embodiment wherein the pin includes a flexible body overmoulded
onto rigid rings arranged perpendicular to the clevis mounts of the
case.
[0019] FIG. 5 shows a similar schematic view to FIG. 2 of a fourth
embodiment wherein the pin includes a rigid body onto which rings
made of a flexible material, such as an elastomer, are
overmoulded.
[0020] FIG. 6 shows a similar schematic view to FIG. 2 of another
embodiment wherein a notch forming a break-off point is situated
between a horn of the case and the end of the bracelet strand.
[0021] FIG. 7 shows a similar schematic view to FIG. 2 of another
embodiment wherein a notch forming a break-off point is situated
between a pump housed in a blind hole in a horn of the case on the
one hand, and the end of the bracelet strand on the other.
[0022] FIG. 8 shows a similar schematic view to FIG. 2 of the same
first embodiment wherein the holes of the clevis mount of the case
are bushed.
[0023] FIG. 9 shows a similar schematic view to FIG. 2 of the same
first embodiment wherein the holes of the clevis mount of the
bracelet strand are bushed.
[0024] FIG. 10 shows a schematic perspective view of a second
variant wherein the fastening element includes means of absorbing
torsion torque, shown here in a particular embodiment with an end
link which is more flexible than the bracelet strand.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0025] The invention concerns the fields of horology and jewellery
and more specifically the field of assembled units, such as
wristwatches, including several components assembled to each other
by a hinged connection.
[0026] The invention is described here with a preferred and
non-limiting application relating to the securing, particularly of
the hinged type, of bracelet strands to a watch case; it could also
concern the securing, particularly of the hinged type, of a
bracelet strand to a clasp, or even of two components of a bracelet
secured and/or hinged to each other.
[0027] The invention concerns a device 100 for fastening a bracelet
strand 3 to a case 2 of a watch 4.
[0028] According to the invention, this device 100 includes at
least one fastening element 101 making it possible to detach the
bracelet strand 3 from the case 2, when said fastening element 1 is
subjected to a predetermined force or moment, and in particular to
a traction force of less than 330N. Preferably, fastening element
101 is arranged to break when it is subjected to a force comprised
between 300 N and 330 N.
[0029] In a first variant illustrated by FIGS. 1 to 9, this
fastening element 101 includes at least one watchmakers pin 1,
which includes at least one shoulder 10 extending in an axial
direction D1. This pin 1 is a sacrificial pin and includes, on
shoulder 10 thereof, at least one area 11 of mechanical resistance
lower than 45 MPa, in the case of a watch case made of MABS or ABS
or similar.
[0030] In a second variant, as seen in FIG. 10, fastening element
101 includes at least one end link 103, and this end link 103 is a
flexible link including a first end 104 to be secured to case 2 and
a second end 105 to be secured to bracelet strand 3, and including
means of absorbing torsion torque so that the reduction factor
between a torsion torque applied to second end 105 and the
resulting torsion torque at the first end 104 is higher than a
factor 10. This fastening element 101 may, in particular, be made
in a single piece of elastomer material or similar, or a flexible
material, so as to absorb most of the torsion moment. It may also
include a ball and socket joint with a free connection between the
socket and the ball of the joint, or other element.
[0031] In an embodiment combining these two variants, end link 103
includes, at the first end 104 thereof, a pin 1 of this type.
[0032] The invention also concerns a wristwatch 4 including a case
2 and at least one bracelet link 3 secured to each other. According
to the invention, the connection between bracelet strand 3 and case
2 includes a fastening device 100 of this type.
[0033] In an advantageous embodiment of wristwatch 4, illustrated
in FIGS. 1 to 9, case 2 and bracelet strand 3 are pivotally hinged
about a shoulder 10 of a pin 1 which forms both the hinge pin and
the fastening device 100 and which is a sacrificial pin. According
to the invention, this sacrificial pin 1 includes, on shoulder 10,
at least one area 11 of mechanical resistance lower than the lowest
mechanical resistance of case 2 and than the lowest mechanical
resistance of bracelet strand 3.
[0034] Pin 1 secures bracelet strand 3 to case 2, and protects case
2 in the event of extremestressor inappropriate manipulation of the
bracelet.
[0035] In a particular embodiment illustrated in the Figures, pin 1
includes a plurality of areas 11 of low resistance.
[0036] It is understood that, due to the significant stresses
imparted by the user to the bracelet, significant stresses are
applied to the hinge, and that the invention makes it possible to
preselect the sacrificial element, which, in this case, is the
least expensive and the easiest to change. Breakage of pin 1 occurs
in the event of stresses that are too high, particularly shearing
force.
[0037] The user visually observes the breakage of pin 1 according
to the invention; however the breakage does not necessarily cause
the immediate detachment of case 2 and bracelet strand 3, when pin
1 is held at several points.
[0038] The configuration of a fragile pin according to the
invention is applicable to various types of assembly. FIGS. 1 to 5
show a watch variant including a row of first clevis mounts 5
staggered with a row of second clevis mounts 6 comprised in
bracelet strand 3.
[0039] FIG. 6 shows another variant where the pin is simply
inserted between two end holes 25 of case 2 in horns 24 and it
carries a loop 34 of bracelet strand 3. In comparison to FIG. 1,
this variant describes the simplest case where there are no
staggered clevis mounts but simply a strand with an eye, and a pin
between two horns.
[0040] FIG. 7 shows yet another variant wherein pin 1 includes
pumps 19 at both ends thereof, elastically housed inside blind
holes 29 in horns 28 of case 2.
[0041] In FIGS. 1 to 5, case 2 includes at least a first clevis
mount 5 with a first hole 50 along a first axis D1, and the at
least one bracelet strand 3 includes at least a second clevis mount
6 with a second hole 60 along a second axis D2. This bracelet
strand 3 is fastened to the at least one first clevis mount 5 of
case 2 by sacrificial pin 1. The at least one shoulder 10 is
dimensioned to pass into first hole 50 and into second hole 60, to
pivotally guide and assemble bracelet strand 3 and case 2.
Although, in a simple and economical embodiment, shoulder 10 is
cylindrical, and all of first holes 50 are aligned and have the
same diameter, as is also the case of all the second holes 60, it
is possible to envisage variants having a different geometry. Thus,
deformable variants will be seen below wherein shoulder 10 is not
cylindrical over the entire length thereof when pin 1 is in the
free state. The resistance of pin 1 to traction, shearing, torsion
and fatigue, is lower in each case than the respective lowest
resistance of case 2 and of bracelet strand 3 which the pin
pivotally guides.
[0042] In a particular variant with straight clevis mounts, as seen
in FIGS. 1 to 5, each first clevis mount 5 includes at least a
first lateral face 51 which is radial relative to first axis D1,
namely a first lateral face 51 for each end clevis mount 5, and two
first lateral faces 51 on both sides of each first inner clevis
mount 5. In the same manner, each second clevis mount 6 includes at
least one second lateral face 61 which is radial relative to second
axis D2, two in the case of the Figures which show more first
clevis mounts 5 than second clevis mounts 6. In the position where
bracelet strand 3 is assembled and hinged on case 2 by pin 1, the
said first clevis mounts 5 are alternated with the second clevis
mounts 6 defining interface areas 40 in each of which a first
lateral face 51 faces a second lateral face 61, with an axial play
JA comprised between 0.000 and 0.060 mm.
[0043] This value is suitable for a particular embodiment with a
pin 1 made of DIN 1.4404 steel with a diameter of 1.0 mm, a case 2
made of rigid plastic material, such as MABS "Terlux" or ABS
"Magnum" or similar, a bracelet 3 that is hinged or made of
flexible material, such as flexible plastic material, rubber,
leather, steel etc., with holes 50 with a nominal diameter of 1.0
to 1.1 mm, holes 60 with a nominal diameter of 1.0 to 1.2 mm, said
holes 50 and 60 could be the holes of DIN 1.4404 steel tubes driven
into first clevis mounts 5 and/or second clevis mounts 6.
[0044] It is quite clear that the bar according to the invention
must be adapted to the case and to the bracelet that it connects,
so as to break in the event of excessive load. The employment of
the weakest bar can be generalised for all applications.
[0045] In any event, pin 1 must break for a force applied in any
direction, well below 300 N. In a preferred embodiment, at least
one area 11 of low resistance of pin 1 is situated, when bracelet
strand 3 is assembled and hinged in position on case 2 by pin 1,
perpendicular to an interface area 40, where the shearing stress is
highest.
[0046] In a variant according to FIG. 8, at least a first clevis
mount 5 is bushed with a metal insert 52 including its first hole
50.
[0047] However, preferably, the rings are on the bracelet strand
rather than on the case, as in FIG. 9.
[0048] In a variant according to FIG. 9, at least a second clevis
mount 6 is bushed with a metal insert 62 including its second hole
60. This arrangement is advantageous when bracelet strand 3 is
flexible, since it allows for rigid guiding of pin 1 and may
attenuate wear.
[0049] In yet another variant, first clevis mounts 5 are bushed
with inserts 51 and second clevis mounts 6 are also bushed with
inserts 62.
[0050] Advantageously, the peripheral shoulder 10 of pin 1
includes, over the length thereof, first areas 13 of higher
resistance alternating with second areas 14 of lower
resistance.
[0051] FIG. 3 illustrates an example embodiment where first areas
13 of higher resistance are made of rigid metal material or hard
plastic material, and where second areas 14 of lower resistance are
made of flexible elastomer overmoulded on first areas 13 of higher
resistance.
[0052] Advantageously, at least one said area 11 of low resistance
is formed by the interface area between a second area 14 of lower
resistance and a first area 13.
[0053] FIG. 3 shows a variant where each first area 13 of higher
resistance faces a second hole 60: sections 13 are located
perpendicular to second holes 60 of second clevis mounts 6, whereas
second areas 14, particularly made of elastomer overmoulded on
sections 13 and alternating therewith, face first holes 50 of first
clevis mounts 5: said second areas 14 include flanges 141 and 142,
pin 1 is inserted into holes 50 and 60 with tightening achieved via
these flanges.
[0054] FIG. 4 shows tubular sections 13 perpendicular to second
holes 60 of second clevis mounts 6, whereas second areas 14,
notably made of plastic material such as polyamide or similar,
overmoulded onto sections 13 and forming a single piece element
over the entire length of pin 1, face first holes 50 of first
clevis mounts 5.
[0055] FIG. 5 shows the reverse configuration of FIG. 4: it is the
core which is rigid and the tubes are made of plastic overmoulded
on the pin.
[0056] In another variant, which is not illustrated, each first
area 13 of higher resistance faces a first hole 50. Tubular
sections 13 are perpendicular to first holes 50 of first clevis
mounts 5, while second areas 14 made of elastomer overmoulded onto
sections 13 and forming a single piece element over the entire
length of pin 1, face second holes 60 of second clevis mounts
6.
[0057] In some variants, at least one area 11 of low resistance is
formed by a second area 14 of lower resistance.
[0058] FIGS. 1 and 6 to 9 illustrate variants where at least one
area 11 of low resistance includes at least one notch 12 or where
every area of low resistance 11 includes a notch 12. This notch
preferably has a V-shaped profile or similar, so as to form a
break-off point.
[0059] In a particular embodiment, pin 1 is made of a plastic
material chosen from among polyoxymethylene (POM),
polytetrafluorethylene (PTFE) filled with glass fibre to improve
its mechanical features, poly(p-phenylsulfide) (PPS) filled with
glass fibre to improve its mechanical features, polyamide-imide
(PAI), polyether ether ketone (PEEK), or even polybenzimidazole
(PBI), or suchlike.
[0060] The invention also concerns a sacrificial watchmakers pin 1
including at least one shoulder 10 extending in an axial direction
D1 and which includes, on said shoulder 10, at least one area 11 of
mechanical resistance lower than 45 MPa, the value depending on the
construction and material of watch case 2, said value of 45 MPa
corresponds to a case 2 made of MABS or ABS.
[0061] This sacrificial pin 1 may be made in accordance with any of
the arrangements described above for pin 1 of wristwatch 4 and
illustrated in the Figures.
[0062] The invention is particularly well suited to the protection
of watch cases made of light or fragile materials, such as plastic
materials, light alloys, glass, in particular when they are hollow
and/or made with walls of small thickness on bracelet fastening
elements. The invention offers the advantage of protecting both the
case and the associated bracelet strand.
[0063] The invention makes it possible to improve a watch simply by
replacing, in the initial assembly or after sales-service, existing
pins or bars with a sacrificial pin according to the invention,
which is inexpensive and requires no modification of the assembly
process.
* * * * *