This invention concerns an installation tool for a blind fastener in a structure.
A "blind" fastener is commonly referred to as a fastener that can be
installed in structures to be assembled from a single side, called front or
accessible side, by deforming a part of the fastener placed on the rear side,
accessible or otherwise, of said structures. Deformation takes place radially
outwardly during a pulling or torqueing phase, to form a bulb or flaring, said
deformation in abutment against the rear side. The structures to be assembled
are thus held tight between a head of the fastener placed in abutment against
10 the front face, and the deformed part in abutment against the rear face.
Among the types of blind fasteners, there is a first type called a "pull-thru"
rivet, comprising a sleeve and a breakable mandrel linked together at one end
of the fastener, with the rivet installed by applying only to the mandrel a pulling
force while maintaining the sleeve stationary in translation, until fracture of the
is mandrel with application of a predetermined pulling force. A second type called
a "screw rivet", comprises a threaded sleeve and a threaded mandrel, with the
rivet installed by applying a torque only to the mandrel while maintaining the
sleeve stationary in rotation, until fracture of the mandrel with application of a
predetermined torque. A third type comprises blind nuts, comprising a threaded
20 nut and a removable mandrel, with the nut installed by screwing the removable
mandrel in the nut, by pulling or turning the mandrel until a given pulling or
torque setpoint, then by unscrewing the mandrel from the installed nut. Finally, a
fourth type called "pull-torqued", comprises a pin equipped with a head and a
gripping element, and a threaded sleeve equipped with a collar, to which a
25 relative pulling force is applied to move the position of the pin with respect to the
threaded sleeve and deform a portion of the sleeve to form a bulb against the
rear face of said structure. In this last type, the gripping element is broken with
2
the application of a predetermined torque. Such a fastener is, for example,
described in the FR3016417 application of the applicant.
One objective of the invention is to provide a manual installation tool for
5 blind fasteners of the "pull-torqued" type.
For this, the invention provides an installation tool for a fastener in a
structure via the front face of the structure.
The fastener comprises a shank with a head and a threaded end, a
gripping element that can be fractured with the application of a predetermined
10 fracture torque and a threaded sleeve able to be deformed outwardly to form a
bulb against a rear face of said structure.
The installation tool comprises:
a body, substantially of a revolution, extending along a longitudinal X
axis, comprising at a first front end an axial opening allowing
is feedthrough of the gripping element and the fastener head,
a first sleeve movable axially and rofationaily in the body, capable of
driving the gripping element of the pin in axial translation and in
rotation around the X axis;
a second sleeve movable axially in the body and immovable
20 rotationally, said second sleeve being arranged to drive the first
sleeve in axial translation;
- a rotational drive means comprising a rotary shaft provided with:
o a first free wheel which can drive the first sleeve in rotation in a
first rotation direction of the shaft,
25 o a second free wheel that can rotate a driving element arranged
coaxially around said second free wheel in a second rotation
direction of the shaft, opposite to the first rotation direction,
with the driving element cooperating via helical link with the
second sleeve so as to move said second sleeve in axial
30 translation.
The installation tool obtained Is used to install blind fasteners of the "pulltorqued"
type with a simple and mechanically robust architecture that requires
3
few elements to achieve the pulling movement and rotation movement
performed successively to install a fastener.
The installation tool for a fastener according to the invention also
presents preferably all or some of the following characteristics, taken alone or in
5 a technically operable combination:
the driving element is a threaded pin, a ball screw, a roller screw or a
worm screw.
the first sleeve comprises movable elements adapted for cooperating
with the blocking portion of the gripping element of the fastener to secure
10 the fastener in the axial direction with the first sleeve.
a first ring is positioned on the first sleeve to be capable of sliding
between a first position in which the movement of movable elements is
blocked in the radial direction and a second position in which the
movement of movable elements is free in the radial direction.
15 - a second ring is capable of sliding along the axial direction on the body
and interfaced with the first ring to bring the first ring only to the second
position.
the first free wheel is slidably mounted in the axial direction on the
turning shaft.
20 - the first free wheel is mounted on a third ring slidable in the axial
direction on the turning shaft.
a compression spring is placed between the third ring and the driving
element.
a spring device is secured to an end of the driving element and to
25 another end of the body; this spring device is tensioned upon rotation of
the shaft in the second direction and slackens to push the driving element
when the rotation of the turning shaft is stopped and/or reversed.
- the spring device is a torsion spring or a spiral spring.
30 The invention also concerns an installation procedure for a fastener
using an installation tool according to the invention.
According to the procedure it consists of the following steps:
4
- engaging the gripping element for a fastener to be installed in
i the opening of the body of the installation tool to secure the
i fastener in translation and rotation with the first sleeve and
! engaging the fastener in an opening in the structure, then;
: 5 -rotating the shaft in the second direction to move the second
sleeve in axial translation, which drives the first sleeve in axial
translation in the pulling direction of the fastener pin, for a
distance ensuring the formation of a bulb via deformation of the
sleeve, then;
10 - rotating the shaft in the first rotation direction to drive the pin
in rotation to the tightening torque of the pin for which the
i gripping element separates from the rest of the pin via a
fracture at the level of a shear groove.
15 Other objects, features and advantages of the invention appear on
•I reading the description of the invention creation procedures, a description
relating to drawings in which:
Figure 1 is a cross-section of a blind fastener of the prior art of the
i "pull-torqued" type;
20 - figure 2 is a cross-section of the installation tool in a resting
configuration,
figure 3 is a cross-section of the installation tool and the fastener from
figure 1 in a configuration in which the fastener is inserted in the
installation tool and through a structure,
25 - Figure 4 is a cross-section of the installation tool and the fastener
inserted in a structure during a bulb formation step;
Figure 5 is a cross-section of the installation tool and the fastener
inserted in a structure during a torqueing step;
Figure 6 is a detailed cross-section of the installation tool and the
30 fastener inserted in a structure during a fracture step of the gripping
element of the fastener;
5
- Figure 7 is a detailed cross-section of the installation tool and the
broken gripping element of the fastener during an ejection step.
To facilitate understanding of the drawings, only the elements necessary
for understanding the invention are shown. The same elements have the same
5 references from one drawing to another.
Attention is drawn to the fact that the cross-sections of the nose
equipment presented on the various figures are not shown in the same axial
plane. In particular, views 2, 3 and 7 are shown in a first axial plane and views
4, 5 and 6 are shown on another axial plane.
10
With reference to figure 1, a blind fastener 10 of the "pull-torqued" type to
which the invention applies comprises a pin 12 and a sleeve 14. The pin 12
comprises a gripping element 16 capable of being broken during installation of
the fastener, a rupture groove 18, a countersunk head 20, a cylindrical shank 22
15 and a threaded end 26. The gripping element 16 comprises a first gripping
portion 28 in the form of a cylinder, a blocking portion 30 and a second gripping
portion 32, comprising splines distributed over the external surface.
The sleeve 14 comprises an enlarged collar 40 capable of receiving the
countersunk head 20, and a tubular shank 42 including a tapping 48, placed at
20 the end of the sleeve 14, opposite the collar 40. The thread of the pin 12 and
the tapping of the sleeve 14 are complementary. The tubular shaft 42 comprises
a deformable zone, not indicated on the drawing, with a stiffness less than the
stiffness of other portions, capable of forming a bulb when pulling is applied.
Figure 2 is a cross-section of the nose equipment 200 of a tool adapted
25 to installation of a blind fastener 10 previously described. The equipment nose
comprises a body 210, substantially a revolution, substantially cylindrical, hollow
extending along an axis X, including a first end 212 and a second end 218
opposite the first. For convenience, in the remainder of the description the first
end 212 is called the front end and indicates the "forward" direction, whereas
30 the second end is called the rear end and indicates the "rearward" direction.
The terms "in translation" and "axially" are used in an equivalent manner to
designate a linear movement along the X axis.
6
The front end of the body (210) comprises a contact surface 214
arranged to enter into contact with the collar 40 of the threaded sleeve, and an
opening 216 sufficient in diameter to enable passage of the gripping element 16
and the head 20 of the pin 12 within said body.
5 The body 210 receives a first sleeve 220, movable in rotation and in
translation within said body. The first sleeve is of a substantially tubular
revolution around the X axis of the body. It extends between the first end close
to the front end 212 of the body, and a second opposite end. A first ring 222 is
located on a first portion of the first sleeve 220 adjacent to the first end of the
10 first sleeve. The elements 224, distributed around the axis, movable in at least
one component of the radial direction are maintained within the body 210
between the front end 212 of the body and the first sleeve 220. The first ring
222 is movable axially on said first portion of the first sleeve, between a first
position in which the movable elements are partially surrounded by the first ring
is 222 (figure 2) and free to move radially, and a second position in which the
movable elements are totally surrounded by the first ring 222 (figure 3) that
blocks their movement in the radial direction.
A first compression spring 226 is located between the first ring 222 and a
second sleeve 230. Under the effect of the first compression spring 226, the first
20 ring 222 is pushed axially forward. In the resting position of figure 2, the travel of
the first ring 222 forward is limited by the movable elements 224 whose ends
closest to the front form a cone presenting an external diameter greater than the
internal diameter of the first ring 222.
A second-ring 228 is positioned around the body 210, close to the front
25 end 212 of said body. The second ring 228 can slide along the body toward the
rear, against a second compression spring 229.
The second sleeve 230 is housed within the body 210. It is movable
axially within the body but maintained immovable in rotation. The second sleeve
in revolution is substantially tubular around the X axis of the body and extends
30 between, at the front, an end of a first portion 232 close to the second end of
the first sleeve 220, and at the rear, a second opposite end. The second sleeve
230 comprises an outside surface of type six or eight faces engaged in the
7
surfaces complementary to the body 210 to immobilize the second sleeve in
rotation in the body. Other anti-rotation devices enabling translation are
possible, like retainer devices, keys or other splices.
The first portion 232 of the second sleeve covers a second portion 228 of
5 the first sleeve 220, adjacent to the second end of the first sleeve. A surface
external to the second portion 228 of the first sleeve forms an external shoulder
and an internal surface of the first portion 232 of the second sleeve forms a
stop, close to the front end of said first portion of the second sleeve, receiving
the shoulder of the first sleeve. The shoulder and the stop comprise the
10 complementary bearing surfaces enabling the transfer of a translation
movement of the second sleeve 230 to the first sleeve 220 toward the rear end
218 of the body. Other drive means can be used in translation of the first sleeve.
The body 210 also comprises a driving means able to drive the first
sleeve 220 in translation and in rotation, and able to drive the second sleeve
15 230 in translation. The driving means comprise a shaft 240 extending along the
X axis between the second end of the first sleeve 220 and the rear end 218 of
the body. The shaft is rotatably mounted around a longitudinal axis of said shaft
and can be rotated in the two possible rotation directions around its axis. In the
front, the shaft is equipped at a first end with a first free wheel 242, positioned at
20 an interface with the second portion 228 of the first sleeve 220. The shaft
comprises at a second end near the rear end 218 of the body a driving means
for rotation (not shown) that can bring the shaft in a rotation direction and in the
reverse direction. A second free wheel 244 is arranged around the shaft 240,
adjacent axially between the first free wheel 242 and the driving means for
25 rotation of the shaft. A driving element 246 is arranged coaxially around the
second free wheel 244.
Each free wheel 242, 244 conventionally comprises an internal ring and
an external ring such that, in a rotation direction, the free wheel turns freely
without securing the internal ring with the external ring - a phase called free
30 wheel, and in the other rotation direction the internal ring is secured to the
external ring and transfers a torque to the part linked to the externa! ring.
8
The first free wheel 242 is positioned to drive the first sleeve 220 in
rotation during a rotation of the shaft in a first rotation direction. The second free
wheel 244 is positioned to drive the driving element 246 in rotation during a
rotation of the shaft in a second rotation direction, reverse to the first rotation
5 direction. The free wheels'242 and 244 are in free wheel phase in opposite
directions of rotation. The first free wheel 242 transfers a torque in the rotation
direction identical to the screwing direction of the pin 12 in the sleeve 14.
The first free wheel 242 is slidably mounted along the shaft 240 using a
third ring 248 coaxial with the shaft that can slide on the shaft. The third ring
10 248 and the shaft 240 are secured in rotation, for example, via a hexagonal face
or another anti-rotation form, or via any other mechanical means such as a
retainer device or key. The third ring 248 comprises a stop 250 in bearing, on
the one hand, against an internal shoulder of the second portion 228 of the first
sleeve, and on the other hand, against the first free wheel 242. A third
15 compression spring 252 is housed around the shaft 240, between an interna!
shoulder of the driving element 246 and the third ring 248.
The driving element 246 comprises a first portion 254 positioned
coaxially around the second free wheel 244, and a second portion 256 extends
coaxially around the shaft, at a distance from the shaft. In this example, the first
20 portion 254 of the driving element comprises an external driving surface for
rotation, for example, for example a hexagonal faces, and the second portion
256 of said driving element comprises an external surface of ball screw type.
The ball screws cooperate with an internal surface of the second sleeve 230 of
the ball screw type. Due to the helical link between the driving element 246 and
25 the second sleeve 230, and the fact that the second sleeve 230 is immovable in
rotation in the body 210, the rotation of the driving element 246 brings the
translation of the second sleeve 230 toward the rear of the body when the shaft
is subjected to a rotation in the direction of transmission of the torque of the
second free wheel. In this rotation direction, the first free wheel 242 is in free
30 wheel condition and does not bring the first sleeve into rotation.
9
Other types of helical links between the driving element and the second
sleeve are possible, such as links using traditional pins/nuts, roller screws or
worm screws.
The first portion 254 of the driving element 248 forms a collar 258
5 extending radially outwardly. A spiral spring 280 is housed in the radial direction
in the body 210 around the first portion 254 of the driving element, an end of
said spring being secured to said first portion 254, whereas the other end is
secured to the body 210. The spiral spring is contained in the axial direction
between the collar 258 of the first portion of the driving element and a stop 262
io of the body. The spiral spring 260 is tightened on itself when the shaft is subject
to a rotation in the blocking rotation direction of the second free wheel 244. The
spiral spring unwinds when the shaft is subject to a rotation in the reverse
rotation direction.
As a variant, the spiral spring can be replaced by a torsion spring. The
is spiral spring is less cumbersome and provides more adjustment latitude than
the torsion spring.
The installation tool also comprises an ejector comprising a rod 272 of
which one end can slide in the shaft 240, a fourth compression spring 274
housed in a space within the shaft 240 and pushing the rod 272. The ejector
20 also comprises a bearing element 276 positioned at an end opposite the rod
272, which can slide in the first sleeve 220 and bears against an external
surface of the first portion 28 of the gripping element 16 of the pin. In resting
state, in which no fastener is inserted in the equipment nose, the bearing
element 276 .of 4he ejector is pushed by the fourth compression spring 274
25 forward to face the opening 216 of the body 210.
The installation procedure for a blind fastener 10 using the equipment
nose 200 will now be described, in relation to the figures 3 to 7.
In a first step, an operator grips a fastener 10 in a state represented in
30 figure 1 and inserts it via the front opening 216 of the body. The gripping portion
28 of the pin pushes the movable elements 224 radially outwardly which click
into place in the blockage portion 30 of the fastener once the first gripping
10
portion 28 of the pin is completely inserted in the equipment nose (figure 3). The
movable elements 224 thus present an external diameter less than the internal
diameter of the first ring 222, which is free to slide forward under the action of
the first compression spring 226, so as to capture the movable elements around
5 the gripping portion of the fastener (figure 3) and to block the fastener 10 in the
equipment nose in the axial direction.
When the first portion 28 of the gripping element is entirely contained in
the equipment nose 200, the bearing element 276 of the ejector, pushed
rearward, compresses the fourth compression spring 274 in the shaft 240.
10 The fastener 10 is then inserted in at least two elements of structure 400
to be assembled, presenting a front face 402, next to which the fastener is
inserted, and a blind face 404 opposite to the front face. For simplicity, the
structure is represented generally on figures 3 to 6 without representing the
elements that are assembled to constitute it. The contact surface 214 of the
15 body lies on the collar 40 of the fastener.
The first step consists of forming a bulb against the blind face 404 of the
structure. To do this, the shaft 240 is rotated in the rotation direction of the
second free wheel 244. The spiral spring 260 is tensioned, a translation is
imposed on the second sleeve 230 via the pin/ball nut link. The second sleeve
20 230 moves rearward (Figure 4 - arrow F1) and drives the first sleeve 220 by
engaging the bearing surfaces of the shoulder of the first sleeve 220 and the
first stop of the second sleeve 230, as well as the third ring 248 positioned
around the shaft, thereby causing the first free wheel 242 rearward, and
compressing the third compression spring 252.
25 The first sleeve 220 and the first ring 222 drive the gripping element 16 of
the pin rearward, and thus the threaded portion 26 of the pin and the tapping 48
of the sleeve toward the blind face 404 of the structure, until the formation of a
bulb 58 of which a face comes in abutment against the blind face 404. The head
20 of the pin 12 is thus contained in the body 210 of the installation tool. The
30 contact surface 214 of the body still holds the sleeve 14 in the structure 400
(figure 4).
11
The second step consists of screwing the pin 12 in the sleeve 14 to bring
the head 20 of the pin in the collar 40 of the sleeve. The rotation exerted on the
shaft 240 is stopped and a reverse rotation movement is imposed. The
combined actions of the spiral spring 260 and the third compression spring 252
5 drives the second sleeve 230 in translation and the third ring 248 forward (figure
5, arrow F2), whereas the rotation of the shaft in the rotation direction of the first
free wheel 242 brings the first sleeve 220 into rotation in the screwing direction
of the pin, in the forward direction. In this rotation direction, the second free
wheel 244 is in free wheel phase, and does not bring the driving element in
10 rotation 246.
Figure 5 illustrates the end of this movement: the first sleeve 220, the
second sleeve 230, the first free wheel 242 and the third ring 248 are returned
to their initial position as seen in figure 2, the head 20 of the pin once again in
abutment against the collar 40 of the sleeve.
15 The third step consists of finalizing the installation of the rivet by
fracturing the gripping element 18 of the pin by continuing to turn the shaft 240
in the rotation direction of the first free wheel 242. The rupture groove 18 is
designed to fracture beyond a certain tension torque ensuring the desired
tightening for the fastener. It therefore fractures once the threshold is reached,
20 leaving the head 20 flush with the front surface 402 of the structure (figure 8).
To eject the broken gripping element 16, the operator grips the second
ring 228 and pulls it rearward of the body. Using a retainer system, the first ring
222 is pulled rearward (figure 7). In doing so, the first ring 222 frees the front
end of the movable elements 224 which are once again radially movable. The
25 ring 222 no longer maintaining the movable elements 224 in the blocking
portion 30 of the gripping element 16, the bearing element 276 of the ejector is
pushed forward under the action of the fourth compression spring 274, which
ejects the gripping element 16 from the equipment nose 200. The ejector also
pushes the movable elements radially, which take their initial positions in
30 figure 2, holding the first ring 222 in a rear position when the operator releases
the second ring 228, and the second compression spring 229 returns the
12
second ring 228 to the initial position of figure 2. Another blind fastener can be
installed according to the same procedure.
This manual installation tool manual can be used with all fasteners of
"pull-torqued" type by adapting the movable elements 224 and the gripping
5 means of the'sleeve 220 to the shape of the gripping element 16 of the pin.
Of course, the installation tool 200 can also install fasteners with
protruding heads.

CLAIMS
1. Installation tool for a fastener (10) in a structure (400) via a front face of
said structure, said fastener being of the type including a pin (12) comprising a
5 shank (22) with a head (20) and a threaded end (26), a gripping element (16) that
can be fractured with the application of a predetermined fracture torque and a
threaded sleeve (14) capable of becoming deformed toward the outside to form a
bulb against a rear face of said structure:
a body (210), substantially a revolution, extending along a longitudinal X axis,
10 comprising a first end in front (212) of an axial opening (216) allowing
feedthrough of the gripping element (16) and the fastener head (20),
a first sleeve (220) movable axially and rotationally in the body (210), capable
of driving the gripping element (16) of the pin in axial translation and in rotation
about the X axis;
is - a second sleeve (230) movable axially in the body (210) and immovable in
rotation, said second sleeve being arranged to drive the first sleeve in axial
translation (220);
the means for rotation about the X axis comprising a turning shaft (240)
provided:
20 o with a first free wheel (242) that can drive the first sleeve (220) in rotation in
a first rotation direction of the shaft,
o with a second free wheel (244) that can rotate a driving element (246)
positioned coaxially around said second free wheel in a second rotation
direction of the shaft, opposite to the first rotation direction, with the driving
25- - element (246) cooperating via helical link with the second sleeve (230) so
as to move said second sleeve in axial translation.
2. Installation tool for a fastener as claimed in 1, in which the driving element (246)
is a threaded pin, a ball screw, a roller screw or a worm screw.
30
3. Installation tool for a fastener as claimed in 1 or 2, in which the first sleeve (220)
comprises movable elements (224) capable of cooperating with the blocking
portion (30) of the gripping element (16) of the fastener (10) to secure said
fastener in the axial direction with said first sleeve.
14
4. Installation tool for a fastener as claimed in 3, comprising a first ring (222)
positioned on the first sleeve (220) capable of sliding between a first position in
which the movement of the movable elements (224) is blocked in the radial
5 direction and a second position in which the movement of movable elements is
free in the radial direction.
5. Installation tool for a fastener as claimed in 4, comprising a second ring (228)
capable of sliding according to the axial direction on the body (210) and interfaced
10 with the first ring (222) to bring the first ring only to the second position.
6. Installation tool for a fastener as claimed in 1, in which the first free wheel (242) is
assembled sliding along the axial direction on the shaft (240).
15 7. Installation tool for a fastener as claimed in 6, in which the first free wheel (242) is
assembled on a third ring (248) assembled sliding along the axial direction on the
shaft (240).
8. Installation tool for a fastener as claimed in 7, in which a compression
20 spring (252) is positioned between the third ring (248) and the driving
element (246).
9. Installation tool for a fastener as claimed in 1 or 2, including a spring device
attached to an end of the driving element (246) and another end to the
25 body (210), this spring device is tensioned during rotation of the shaft (240) in the
second direction and slackens to push the driving element when the rotation of
the turning shaft is stopped and/or reversed.
10. Installation tool for a fastener as claimed in 9, in which the spring device is a
30 torsion spring or a spiral spring.
11. Installation procedure for a fastener (10) using an installation tool compliant with
one of the preceding claims, such procedure comprising the following steps:
15
- engaging the gripping element (16) of a fastener (10) to be installed in the
opening (216) of the body (210) of the installation tool to secure said fastener in
translation and rotation with the first sleeve (220) and engaging the fastener in a
perforation in the structure (400), then;
5 - rotating the shaft (240) in the second direction to move the second sleeve
(230) in axtattranslation, which brings the first sleeve (220) in axial translation in
the pulling direction of the fastener pin (12), for a distance ensuring the
formation of a bulb via deformation of the sleeve (14), then;
- rotating the shaft (240) in the first rotation direction to bring the pin (12) in
io rotation up to the tightening torque of the pin for which the gripping element (16)
separates from the rest of the pin via a fracture at the level of a shear groove
(18).