U.S. patent application number 09/851334 was filed with the patent office on 2001-09-13 for separable coupling and corresponding tool.
Invention is credited to Bozonnet, Daniel.
Application Number | 20010020405 09/851334 |
Document ID | / |
Family ID | 9476115 |
Filed Date | 2001-09-13 |
United States Patent
Application |
20010020405 |
Kind Code |
A1 |
Bozonnet, Daniel |
September 13, 2001 |
Separable coupling and corresponding tool
Abstract
At least one of two components (1, 3) of a coupling includes a
profile with four splines (5) having more or less radial edges
(11). Four straight-line segments (6) on the inside of the profile
are joined with the splines. The four straight-line segments (6)
are designed to circumscribe a standardized square drive (14). This
profile can be used for driving sockets and accessories for
screwing and unscrewing.
Inventors: |
Bozonnet, Daniel; (Nevers,
FR) |
Correspondence
Address: |
WENDEROTH, LIND & PONACK, L.L.P.
2033 K STREET N. W.
SUITE 800
WASHINGTON
DC
20006-1021
US
|
Family ID: |
9476115 |
Appl. No.: |
09/851334 |
Filed: |
May 9, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09851334 |
May 9, 2001 |
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08894063 |
Dec 8, 1997 |
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08894063 |
Dec 8, 1997 |
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PCT/FR96/00206 |
Feb 7, 1997 |
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Current U.S.
Class: |
81/436 |
Current CPC
Class: |
F16D 3/185 20130101;
F16D 1/101 20130101 |
Class at
Publication: |
81/436 |
International
Class: |
B25B 015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 14, 1995 |
FR |
95 01 675 |
Claims
What is claimed:
1. A torque transfer component comprising a female driving portion
having a useful height and a transverse cross-section profile, the
profile comprising: four inner wall segments disposed on a square
which circumscribes a square drive; four splines projecting
radially outward from respective corner regions of said square,
each of said splines being respectively delimited by two lateral
edges and an outer edge; first rounded portions joined to
respective said lateral edges wherein said first rounded portions
circumscribe first arcs defined by a first radius; second rounded
portions tangentially joining respective first rounded portions to
said inner wall segments wherein said second rounded portions
circumscribe second arcs defined by a second radius which is
greater than said first radius; and wherein said profile is
constant over the entire useful height of the female driving
portion.
2. The torque transfer component according to claim 1, wherein the
square drive has a dimension selected from the group consisting of
6.35 mm, 9.53 mm, 12.70 mm, 15.88 mm, 19.05 mm, 25.40 mm, 38.10 mm,
and 63.50 mm.
3. A torque transfer component comprising a female driving portion
having a useful height and a transverse cross-section profile, the
profile comprising: four inner wall segments disposed on a square
which circumscribes a square drive; four splines projecting
radially outward from respective corner regions of said square,
each of said splines being respectively delimited by two lateral
edges and an outer edge; rounded portions joined to respective said
lateral edges; straight-line wall segments joining at an angle
respective said rounded portions to respective said inner wall
segments by a ridge; and wherein said profile is constant over the
entire useful height of the female driving portion.
4. The torque transfer component according to claim 3, wherein the
square drive has a dimension selected from the group consisting of
6.35 mm, 9.53 mm, 12.70 mm, 15.88 mm, 19.05 mm, 25.40 mm, 38.10 mm,
and 63.50 mm.
5. A tool, comprising: a female torque transfer component including
a female driving portion with a flared entry and having a useful
height, said female driving portion defining a cavity profile in a
transverse cross-section, said cavity profile including four inner
wall segments disposed on a square which corresponds to a square
drive, four splines projecting radially outward from respective
corner regions of said square, each of said splines being
respectively delimited by two lateral edges and an outer edge,
rounded portions which join respective said lateral edges to said
inner wall segments, and wherein said profile is constant over the
entire useful height of said female driving portion; and a male
torque transfer component adapted to be co-axially mated with said
female torque transfer component, said male torque transfer
component including a male driving portion which exhibits in at
least one transverse cross-section thereof, to within an operating
clearance, a male profile adapted to be conjugated with said cavity
profile of said female torque transfer component, and a nose
comprising a proximal cone frustum and an end cone frustum, said
end cone frustum forming a smaller angle with an axis of said male
driving component than said proximal cone frustum.
Description
[0001] This application is a continuation of U.S. application Ser.
No. 08/894,063, filed Aug. 12, 1997.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a separable coupling
between a male component and a female component which is used with
to a tool for rotationally driving a screw or a nut.
[0004] 2. State of the Prior Art
[0005] Current couplings normally use conjugate male square drives
and female square drives, defined for example by ISO standard 1174.
The male square drive is generally integral with the head of the
tool and can fit into the female square of a socket which, at its
opposite end, has a driving profile designed for tightening or
loosening screws or nuts. This socket may form part of a family of
sockets associated with the dimension of the square drive in
question. As an alternative, the male square may fit into the
female square of other members such as an extension piece, a
universal joint, etc.
[0006] The standardized dimensions of square drives correspond to
sides 6.35 mm (1/4), 9.52 mm (3/8), 12.70 mm (1/2) long, etc. For a
given square drive, corresponding to a given tool size, the torque
is limited by the mechanical strength of the male square drive This
greatly limits the range of sockets that can be used. For a given
threaded member, the torque required for loosening is greater than
the nominal tightening torque. This amount of torque is largely
unpredictable, and this unpredictability can be caused by
corrosion.
[0007] As a result, if the required torque is greater than the
torque capacity of the male square drive, it becomes necessary to
change the tool and to use the square drive with the next size up.
This assumes that several tools and several boxes of sockets are
available, and leads to the use of heavier, bulkier and more
expensive tools.
[0008] Various proposals have been made for increasing the torque
available for a given tool and with a specific hardness of steel.
However, this usually involves the use of shapes derived from a
hexagon (FR-A-1,560,270 and 2,682,727, U.S. Pat. Nos. 4,512,220,
4,361,412 and 4,930,378, EP-A0,458,771), which exhibit the drawback
of being incompatible with standardized male square drives.
[0009] In addition, the known profiles are not generally designed
to be equipped satisfactorily with a locking ball acted upon by a
spring (as far as the male profile is concerned) or with a recess
for accommodating such a ball (in the case of the female
profile).
SUMMARY OF THE INVENTION
[0010] An object of the invention is to provide a coupling
compatible with a standardized male square drive and making it
possible, for a given size, to obtain torque which is markedly
greater than that corresponding to the square drive, while being
able to be equipped effectively with a ball-type locking device
compatible with that of this square drive.
[0011] To this end, the subject of the invention is a coupling of
the aforementioned type, characterized in that at least one of the
two components exhibits, in transverse section, a splined profile
having four straight-line segments radially on the inside, these
straight-line segments together being designed to circumscribe a
standardized square drive. At the corners of the square, four
splines project radially outwards with respect to the contour of
the square drive, the edges of which extend substantially radially.
The ends of the straight-line segments are joined to the edges of
the splines by rounded portions.
[0012] The coupling according to the invention may, also, have a
splined profile that is substantially constant over the entire
useful height of the corresponding component. Further, the female
component may include, in at least one of its flat faces
corresponding to the straightline segments, a recess for
accommodating a locking member which is acted upon by a spring and
which is borne by a flat face of the conjugate male profile or of
the standardized square. Another feature is that each rounded
portion of the female profile may be joined to the adjacent
straight-line segment via a second rounded portion of markedly
larger radius which is connected tangentially to the first rounded
portion and to the straight-line segment. Further, each rounded
portion of the female profile may be joined to the adjacent
straight-line segment via a second straight-line segment connected
tangentially to the first rounded portion and connected by a ridge
to the first straight-line segment, which forms an angle of a few
degrees.
[0013] The splines may be delimited laterally by edges in the form
of straight-line segments or circular arcs orientated substantially
radially, which connect tangentially, via rounded linking portions,
to the adjacent parts of the profile. The edges of each spline may
have an overall direction which is substantially radial with
respect to the center of the profile. The splines may also be
delimited on the outside by circular arcs belonging to circles
whose centers are situated on the overall axes of symmetry of the
corresponding splines. Mid-point perpendiculars of the
straight-line segments pass through the center of the profile. Each
straight-line segment of the female component may include a hollow
section near its center, over all or part of its length. Further,
the splined profile may be symmetric with respect to the two
directions of rotation. Also, the splined profile may be asymmetric
with respect to the two directions or rotation.
[0014] Another object of the invention is a manual or assisted tool
for rotationally driving a screw or a nut. The tool has a first
component designed to receive a driving torque and exhibiting a
splined profile as defined hereinabove. The tool also has at least
one second component for transmitting the driving torque from the
first component to the screw or to the nut. This second component
exhibits, within the operating clearance, a splined driving profile
conjugate with that of the first component.
[0015] According to other features of such tool, the female splined
profile has a constant section, whereas the male splined profile
has a section which increases up to that of the female profile and
then decreases, in a bi-linear or bulbous fashion. The female
component has a flared entry, whereas the male component has a nose
portion whose rear part is substantially frustoconical. The nose
portion's front part is substantially in the shape of a cone
frustum which is more tapered and is grooved over some of its
length by the inter-spline hollows of the male profile. The front
part may be designed to fit partially into that part of the female
profile, which is delimited by the straight-line segment. Also, the
two splined profiles have similar hardnesses, especially on the
order of 40 to 50 HRC.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Embodiments of the invention will now be described with
respect to the appended drawings, in which:
[0017] FIG. 1 represents a coupling according to the invention, in
transverse section;
[0018] FIG. 2 is a side view of the two components of this coupling
and of a screw which they are to act upon;
[0019] FIG. 3 is an end-on view of a corresponding end piece of a
male component;
[0020] FIG. 4 is an end-on view of a socket of the same
coupling;
[0021] FIG. 5 is a partial view of an alternative of a male
profile;
[0022] FIG. 6 is a partial view of an associated alternative of a
female profile;
[0023] FIG. 7 is a partial view of another alternative of the
female profile;
[0024] FIG. 8 represents an arrangement making it easier to insert
the male profile inside the female profile;
[0025] FIG. 9 shows an alternative of the female profile of FIG.
8;
[0026] FIG. 10 is a partial lateral view of an angular extension
piece having a male profile according to the invention;
[0027] FIG. 11 is an end-on view in the direction of the arrow XI
of FIG. 10; and
[0028] FIGS. 12 and 13 are views similar respectively to FIGS. 10
and 11, of an alternative.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] FIG. 1 represents a profile, in transverse section, of a
driving male end piece 1 represented in FIGS. 2 and 3, as well as
the conjugate profile, within the operating clearance, of a driving
part 2 of a socket 3 represented in FIGS. 2 and 4. A proximal end
of the end piece is, when in use, secured to the head of a driving
tool. The driving tool has not been represented, and can be for
example, a ratchet, an extension piece, or any other accessory. The
socket 3 has, opposite from driving part 2, a working part 4 which
has any known female profile (hexagonal, "TORX", etc.) intended for
engaging with a conjugate threaded member 10 (FIG. 2) to be driven
rotationally, such as a screw, a nut, a tap, etc. The profile
represented is constant over its entire useful height. The
components 1 and 3 have relatively high and relatively similar
hardnesses, typically on the order of 40 to 50 HRC.
[0030] Each of the male and female profiles have the overall shape
of a cross having axial symmetry and include four identical splines
S situated at 90.degree. from one another with respect to a center
0 of the profile, as well as four intermediate straight-line
segments 6. A mid-point perpendicular 7 of each segment 6 passes
through the center 0. The splines S are defined on the outside by
circular arcs 8. The four arcs belong to the same circle 9 centered
at center 0, and they are delimited laterally by two straight-line
segments 11 oriented more or less radially. As far as the female
profile is concerned, concave rounded portions 12 are joined
tangentially to the arcs 8 and to segments 11. Convex rounded
portions 13 are joined tangentially to these segments 11 as well as
to the adjacent segments 6.
[0031] The four segments 6 of the female profile are designed to
circumscribe, to be within the operating clearances, a standardized
male square 14 represented by a broken line. In addition, each of
the flat faces of the female profile includes, over the entire
length of the segments 6 and at a predetermined height, a recess 15
for accommodating a locldng ball 16. The locking ball 16 is acted
upon by a spring, and projects from a flat face of the male
profile. The vertical position of the recess 15 is designed also to
accommodate a locking ball from the standardized male square 14. As
an alternative, the ball 16 may be replaced by a spherical-ended
plunger (not represented).
[0032] If the male profile and the square 14 are compared, it will
be observed that the former has a markedly higher polar moment of
inertia (or polar strength modulus) with respect to the center 0.
This makes it possible to obtain markedly higher torques. In
addition, the shape of the splines 5 allows them to withstand such
high torques. The substantially radial orientation of the segments
11 results in the torque applied to the tool being transmitted
without appreciable loss from the segments 11 of the male profile
to those of the female profile.
[0033] As an alternative, the extensions of the segments 11 may
pass on one or other side of the point 0. The transmission of
torque then develops a centrifugal or centripetal force
component.
[0034] Also as an alternative, the circular arcs 8 may be centered
on other points on the axis of symmetry of the corresponding
splines, situated nearer (point 01) or farther (point 02) than the
point 0.
[0035] Also as an alternative, as indicated by a dashed line in
FIG. 1, a central part of each segment 6 of the female profile may
be a hollow portion 6A. This hollow portion 6A may be applied to
practically the entire length of the segment 6. However, if a
ball-type lock is used, it must lie within the recess 15, as
illustrated.
[0036] In the alternative of FIGS. 5 and 6, the male profile (FIG.
5) is modified by the fact that the straight-line segments 11 are
replaced by convex circular arcs 11A. As far as the female profile
is concerned (FIG. 6); it is modified in two ways. On the one hand,
its straight-line segments 11 are replaced by convex circular arcs
11B, having a radius greater than that of the circular arcs 11A. In
addition, one convex circular arc 13A of large radius R is
interposed between each end of each straight-line segment 6 and the
adjacent rounded portion 13 and connects tangentially to these.
[0037] The effect of these modifications is to position the points
of contact between the two profiles, when torque is applied, close
to the outer ends of splines, which increases the transmitted
torque. On the other hand, it improves the transmission of torque
from the standardized square 14 to the female profile, as explained
in FR-A-2,560,099.
[0038] An alternative, FIG. 7, differs from FIG. 6 merely in that
the arcs 13A are replaced by short straight-line segments 13B
joined tangentially to the rounded portions 13 and forming an angle
a of a few degrees with the segments 6, to which they are connected
by ridges 13C.
[0039] This alternative again improves the transmission of torque
from the standardized male square 14 to the female profile.
[0040] Also as an alternative, the splines 5 and/or the segments 6
may be asymmetric with respect to two directions of rotation, for
example combining two of the alternatives described
hereinabove.
[0041] FIG. 8 represents the adjacent ends of two components
respectively including a male profile and a female profile which
are conjugate in accordance with the invention. It is possible in
particular for these two components to be the male end piece 1 and
the socket 3 of FIG. 2.
[0042] The proximal end of the socket has a chamfer 22, and an
angle x which is, for example, 60 degrees with respect to the axis
of the socket.
[0043] As far as the end piece 1 is concerned, it includes at its
distal end a nose 23 consisting of two successive cone frustums: a
proximal cone frustum 24 with an angle y on the order of 70.degree.
with respect to the axis of the end piece, and an end cone frustum
17 which is more tapered subtending an angle z on the order on
90.degree..
[0044] The distance between flat sides of the corresponding
standardized square, that is to say the distance separating two
opposed segments 6 in FIG. 1, is between the smallest diameter and
the largest diameter of the cone frustum 17. As a consequence, the
four recesses of the profile bite into the cone frustum 17, almost
as far as mid-way along it.
[0045] This arrangement makes it possible to guide the insertion of
the male component into the female component in a way which is
especially convenient for the user.
[0046] As an alternative (FIG. 9), the chamfer 22 may be shortened
from the proximal end portion of the socket 3, and may follow a
second chamfer 18 subtending a smaller angle.
[0047] FIGS. 10 and 11 illustrate the application of the invention
to an extension piece known as an "angular extension". After the
angular extension has been inserted into the female element and
locked axially by the ball or the locking plunger acted upon by a
spring, it allows a certain angular deflection about the diameter
passing through the central axis of this locking member.
[0048] Thus, a distal end of the extension piece, projecting out of
its handle 19, includes a male profile as previously defined, the
dimensions of which increase progressively and homothetically from
the handle 19 to a section 20 of maximum cross-sectional area
corresponding to that of the female element. Then it decreases
progressively as far as a distal end portion 21 of the extension
piece.
[0049] In the example of FIGS. 10 and 11, the increase and decrease
in dimensions take place linearly. In contrast, in the example of
FIGS. 12 and 13, they take place in a domed manner, giving the end
of the extension piece the overall shape of a truncated ball.
[0050] Also represented diagrammatically in FIGS. 10 to 13 is the
visible part of a locking ball 16 borne by the male profile between
two of its splines.
[0051] While preferred embodiments of the present invention are
shown and described, the invention is not intended to be limited by
the foregoing disclosure.
* * * * *