Note: Descriptions are shown in the official language in which they were submitted.
~06730~
SPECIFICATION
Title of the Invention
Structure for Expansion and Contraction o~ Guard
Baton
Background of the Invention
Field o-f the Invention
The present invention concerns a structure for expan-
sion and contraction tube guard baton using a telescopic
pipe constitution and, more in particular, it relates to a
structure ~or expanslon and contraction o~ a ~uard baton
capable of extending and contractin~ extremely smoothly,
with neither rattling nor deviation and having improved
dura~ility.
Descrlption of the Prior ~rt
As an existent structure for expansion and contraction
o~ guard batons o-E this type, there has been known, ~or
e~ample, such a structure that a plurality of cylindrical
members each of di~erent diameter are combined in a
telescopic manner, in which an lnclined outer sur-face at
~he rear end of an inner cylindrical member is engaged to
an înclined inner sur-~ace at the top end of a cylindrical
member ~ust outside thereto in an anti-slip off ~ashion.
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This is a key holder of a telescopic structure whlch is
not the guard baton itsel~ but is applicable thereto (US
Patent No. 4,752,027). Elowever, ln the structure of this
prior art, both of the outer surface and the inner sur-face
at the top end of the outer cylindrical member are formed
as inclined surfaces tapered as far as the top end, while
both of the outer surface and the inner surface at the
rear end of the inner cyllndrical member are also formed
as inclined surfaces tapered as far as the rear end.
Therefore, this structure involves the following problems.
(1) The top end of the inclined inner surface of the
outer cylindrical member is in a sliding contact with the
cylindrical outer surface of the inner cylindrical member
substantially along an annular line of contact, and the
rear end o~ the inelined outer sur~Face of the inner cylindrical
member is also in a sllding contact with the cylindrical
inner surface of the outer cylindrlcal member substantially
along an annular line of contact and they are guided in
this state upon extension and contraction. Accordingly,
the top end of the guide o~ the outer cylindrical member
and the rear end of the guide of the inner cylindrical
member are liable to be abraded and, as a result, a
clearance at the guide portion is increased tending to
cause rattling or deviation.
(~) The rigidity o~` the ~uard baton, when it is extended,
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has been insufficient and this is assumed to be caused by
the rattling described above. In particular, a force or
impaet may sometimes be exerted on the ~uard baton in the
direction in perpend~cular to the axis of the baton and it
is considered that such a force or impact, being coupled
with the rattling, makes the rigidity of the baton insuf-
ficient in a state where it is extended.
(3) If the wall thickness of the cylindrical member is
decreased for the reduction of the weight, the inclined
inner sur~ace of the outer cylindrical member is pushed by
the inclined outer surface of the inner cylindrical member
and tends to be opened outward when the baton is extended
under an intense force. Therefore, the inner dlameter is
enlarged to make the inner cylindr:Lcal member slip out o-f
the outer cylindrical member.
Further, a guard baton of an expanslble and contractlble
structure is disclosed in Japanese Patent Utility Model
Laid-Open Sho 61-181996, in which the inner and outer
members have a plane-to-plane contact portion. However,
in an extended state, a return stopper resiliently
protruded outward ~ormed by notching an inner tubular
member engages the top end surface of the outer tubular
member thereby preventing the inner tubular member from
returning. AccordinglYI there is a problem for the
strength of the notched portion.
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Further, although an expansible and contractible
mechanism is also disclosed in Japanese Utility Model
Laid-Open Sho 63-90796, no detailed inner structure is
mentioned or disclosed.
Summary o-f the Invention
It is, accordingly, an obJect of the present inven-
tion to overcome the ~oregoing problems in the prior art
and provide a structure for expansion or contraction of a
guard baton which causes less rattling or deviation even
a-fter repeating use and which is free from the worry of
slipping off caused by an extending force even if the
weight is reduced.
The foregoing ob~ect of the present invention can be
attained by a structure for expansion and contraction of a
guard baton comprising a plurality of cylindrical members
each o~ different dlameter combined in a telescopic manner,
in which an inclined surface at the rear end of an inner
cylindrical member is made engageable with an inclined
surface at the top end of a cylindrical member ~ust outside
thereto in an extended state, wherein
the top end of the outer cylindrical member has an
outer circumferentlal cylindrical sur-face in parallel with
the cylindrical axis and an inner surface having a conically
inclined surface tapered toward the top end and a circum-
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,
ferential cylindrical slide guide sur-face in contiguous
with the top end of the conically incl~ned surface and in
parallel with the cylindrical axis, and the rear end of
the inner cylindrical member has an outer circumferential
cylindrical slide guide surface in parallel with the
cylindrical axis and a conically inclined surface tapered
toward the top end and in contiguous with the slide guide
surface, in which the slide guide surface of the outer
cylindrical member is put to a slidable contact with the
outer circum~erential sur~ace of the inner cylindrical
member and the slide guide surface of the inner cylindrical
member is put to a slidable contact with the inner circum-
ferential surface of the outer cylindrical member respec-
tively, and a vent hole may be disE)osed to at least one
position of the guard baton.
In a preferred embodiment of the present invention, a
step is disposed between the inner circum-~erential surface
and the base of the conically incllned sur~ace of the
outer cylindrical member and another step is also disposed
between the slide guide surface and the conically inclined
surface of the inner cylindrical member for enabling engage-
ment at the steps.
In another embodimentl an abrasion resistant layer is
formed to the inner surface of the outer cylindrical
member and the outer surface of the inner cylindrical
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member.
In a further embodiment, a ring made of an abrasion
resistant material and having a slide guide surface is
attached to the top end of the outer cylindrical member.
In a further embodiment, a ring made of an abrasion
reslstant material and having a slide guide surface is
attached to the rear end o~ the inner cylindrical member.
In a further embodiment, an angle of inclination
for each of the conical engaging surfaces of the outer
cylindrical member and the inner cylindrical member is
defined as withln a range of 1 to 2.
Upon extension and contraction, the slide guide
surface formed cylindrically to the outer cylindrical
member is put to a plane-to-plane contact with the cylin-
drical outer surface of the inner cylindrical member, and
the slide guide sur~ace formed cylindrically to the inner
cylindrical member is put to a plane-to-plane contact with
the cylindrical inrler surface of the outer cylindrical
surface, respectively, and they are guided in this state.
Therefore, rattling or deviation can be reduced remarkably
as compared with the structure in the prior art. Further,
the structure causeæ less abrasion even after repeating
extension and contraction and can suppress the rattling or
deviation to a reduced level even after long time use.
Further, even if the wall thickness of the cylindrical
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member is decreased, as a whole, to reduce the wei~ht, only
the top end of the outer cylindrical member is -formed
cylindrical at the outer surface to increase the wall
thickness locally. Accordingly, even when a large
extending forces is applled, the member has a great resis-
tance against the force of opening the top end of the
cylindrical member outward, to prevent the inner cylindrical
member from slipping off. In a case where the outer
cylindrical member and the inner cylindrlcal member are
engaged by way of the steps, the anti-slipping function is
further improved. Further, if the angle of inclination
for each o~ the conical engaglng sur-~aces of the outer
cylindrical member and the inner cylindrical member is
made greater than 1. There is no worry that the inner
cylindrical member slips o-f-~ due to slight dimensional
error upon fabrication.
Furthermore, the durability o-f the structure can be
improved remarkably b~ providing a means such as ~orming an
abrasion resistant layer to the inner surface of the outer
cylindrical member or the outer surface of the inner
cylindrical member, attaching a ring made of an abrasion
resistant material and having a slide guide surface to the
top end of the outer cylindrical member or attaching a
ring made of an abrasion resistant material and having a slide
guide sur~ace to the rear end o~ the inner cylindrical
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member.
Particularly, since the guard baton has a su-fficient
rigidity in an extended state. The present lnvention is
particularly effective when it is applied to a guard baton
with a cross handle, to which compressive force is possibly
exerted intensely.
DESCRIPTION OF THE APPENDED DRAWINGS
Fig. 1 is an entire perspective view of an expansion
and contraction type guard baton with a crosshandle as a
first embodiment of the present invention;
Fig. 2 :Ls a vertical cross sectional view of the
guard baton shown in Fig. 1;
Fig. 3 is an enlarged cross sectional view o-E a
portion -Eor explaining a structure for expansion and
contractlon;
Fig. 4 is a slde elevatlonal view partially ln cross
section of a modified embodiment of the guard baton shown
in Fig. l;
Fig. 5 is a cross sectional vlew for a portion of a
structure -for expansion and contraction of a guard baton
main body 1 in a sécond embodiment o-E the present
invention;
Fig. 6 is a cross sectional view for a portion of a
third ambodiment of the present inventlon;
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Fig. 7 is a front elevational view for an abrasion
resistant member in a fourth embodiment of the present
invention;
Fig. 8 is a cross sectional view for a portion of a
fourth embodiment of the present invention;
Fig. 9 is a front elevational view for a portion of
an abrasion resistant member in a fifth embodiment of the
present invention; and
Fig. 10 is a side elevational view of the member
shown in Fig. 9.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Description will now be made to preferred embodiments
of the present invention with referlence to the drawings.
Fig. 1. is an entire perspective view of an expansion and
contraction type guard baton with a croæshandle as a first
embodiment o~ the present invention, Fig. 2 is a vertical
cross sectlonal view thereof and Fig. 3 is an enlarged
cross sectional view of a portion for illustrating a
structure for e~pansion and contraction.
In Fig. 1. a baton main body 1 is shown by a solid
line in a contracted state and by a do-tted chain in a
state extended to a length L. The ~aton main body 1
has a crosshandle 2 with a length as can be gripped by one
hand, which is branched in perpendicular from the batvn
2 0 ~
main body 1 at a position displaced somewhat from the
center to one end in the lon~itudinal direction of the
baton main body 1, that is, at a position near a hilt A
disposed at one end of the baton main body 1. The hilt A
comprises a cylindrical member A1 made of a synthetic
resin, wood or light metal through which the baton main
body 1 is inserted.
As shown in Fig. 2, the crosshandle 2 of this embodi.-
ment has a support shaft 6 extended vertically from a
mounting base 5 for securing to the baton main body 1 in
perpendicular to the baton main body 1 and it is consti-
tuted as an upper/lower rotational type crosshandle, com-
prising a relatively rotational lower member 7 rotatably
put ~it around a base end 6a of the support shaft 6, an
relatively rotational upper member 8 rotatably put around
a top end 6b of the support shaft 6 and a statlc member 9
through which an intermediate portion 6c o~ the support
sha-Pt 6 is inserted and which is secured to the support
shaft 6 at a position between the relatively rotational
upper and lower members 7 and 8.
The baton main body 1 has a telescopic structure
comprising a plurality of (three in the illustrated em-
bodiment) cylindrical members 25, 26, and 27 each of
di-fferent diameter. The outer cylinder 25 of the greatest
diameter has female threads 28 formed at the inner circum-
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ferential surface on the side of the rear end being extendedfrom the opening to the inside, a plug 29 having outer
circumferential threads and screwed at the inside, and a
cap 30 screwed at the rear end opening as a cover. In the
outer cylinder 25, the outer circumferential surface
comprises a cylindrical surface 25a formed in parallel
with the cylindrical axis, and an inner circumferential
surface comprises an inclined surface 25d at the top end,
being tapered (converged) toward the top end. An inter-
mediate cylinder 26 contained at the inside of the outer
cylinder 25, as an inner cylindrical member, has an inclined
sur-face 26f formed to the outer surface on the rear end,
and the outer diameter thereof is slightly enlarged toward
the rear end opening so as to be e~gageable with the
inclined surface 25d of the outer cylinder 25. The top end
of the intermediate cylinder 26 has an inclined surface
26d formed to the inner circumferential sur~ace, being
tapered to the top end. An inner cylinder 27 contained at
~he inslde o~ the intermediate cylinder 26 has an inclined
surface 27~ to the outer surface of the rear end and the
outer diameter thereof is slightly enlarged *oward the
rear end opening so as to be enga~eable with the inclined
surface 26d at the top end of the intermediate inner
cylinder ~6. Female threads are formed at -the inner
surface of the top end opening to which a cap 36 is
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screwed. The rear end o-f the inner cylinder 27 has such
an inner diameter as capable of engaging a -forked spring
38, which is screw-set to the plug 29 ~hen the guard baton
is contracted. The base of the cap 36 at the top end has
such a size capable o* engaging the top end o-f the inter-
mediate cylinder 26.
Referrin~ more specifically to the structure -for
expansion and contraction of the baton main body 1 with
reference to the enlarged cross sectional view of Fig. 3,
the outer cylinder 25 as the outer cylindrical member and
the intermediate cylinder 26 (an outer cylindrical member
to the ~nner cyllnder 27) are shaped at their top end
portions, such that each o~ their outer surfaces 25a 126a)
has no inclination in the axial direction, that is, as a
cyli~ldrical shape having a circumfe~rential surface in
parallel with the cyllndrical axis. On the other hand,
at the inner sur~ace o-f each of the top end portions,
there are formed conically inclined tapered sur-faces 25d
(26d) and a cylindrlcal slide guide sur~ace 25c (26c~
having a circumferential sur-face in parallel with the
cylindrical a~is and conti~uous to the top end Or the
conically inclined surface 25d (26d). On the other hand,
each of the intermediate cylinder 26 as the inner cylindrical
member (inner cylindrical member to the outer cylinder 25)
and the inner cylinder 27 has, at the outer surface of the
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rear end, a cylindrical slide guide surface 26e (27e) as a
circumferential surface in parallel with the cylindrical
axis and a conically inclined tapered surface 26f (27F) in
contiguous with the slide guide surface 26e (27e), orderly
from the rear end.
The slide guide surface 25c at the inner surface on
the top end of the outer cylinder 25 and the cylindrical
outer circumferential surfaee 26a of the intermediate
cylinder 26 in parallel with the cylindrical axis are fit
to each other with a slight clearance, and the slide gulde
surface 26e on the outer surface at the rear end of the
intermediate cylinder 26 and the cylindrical inner
elrcumferential surface 25b of the outer cylinder 25 in
parallel with the eylindrical axis are fit to each other
with a slight clearance. Further, the slide guide
surface 26e on the inner surfaee at the top end o-f the
intermediate eylinder 26 and the cylindrieal outer
eireumferential surface 27a of the inner cylinder 27 in
parallel with the eylindrical axis are fit to each other
with a slight elearanee, and the slide guide surfaee
27e on the outer surEace at the rear end of the inner
eylinder 27 and the eylindrieal inner circumferential
surfaee 26b of the intermediate eylinder 26 in parallel
with the eylindrieal axis are fit to eaeh o-ther with a
slight elearanee.
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At leas~ one bent hole 31 is formed to the circumfe-
rential side o-~ the outer cylinder 25. Alternatively, the
bent hole 31 may be disposed to the intermediate cylinder
26 or the inner cylinder 27, to the cap 30 attached to the
rear end of the outer cylinder or to the cap 36 attached to
the top end of the inner cylinder 27, or the hole may be
replaced with a groove or slit, so long as air can flow
freely between the inside and the outside of the cylindrical
member of the baton main body 1 to ensure smooth extending
and contracting operation.
In this embodiment, an angle o~ inclination for the
conically inclined surface 25d of the outer cylinder, each
of the conically inclined sur-faces 26d and 26f of the
intermediate cylinder and the conical inclined surface 27-
of the inner cylinder 27 is preferably within a range from
1 to 2. If the angle is smaller than 1, it requires a
large force for releasing engageme:nt between each of the
inclined surfaces and containing the intermediate cylinder
26 in the outer cylinder ~5 and the inner cylinder 27 in
the intermediate cylinder 26, respectivel~, thereby making
it difficult to contract the baton main body 1. Further,
depending on the fabrication error, there may be a worry
that the inner cylindrical member slips and -flies out o~
the outer cylindrical member by the swinging force upon
extending the baton main body 1. On the other hand, if
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the angle of inclination is greater than 2, engagement
between each of the inclined sur~aces is weakened in an
extended state to bring about a worry that the engagemen-t
is released by the reaction of thrusting an opponent, to
contract the baton main body 1. By the way, baton main
bodies 1 were experimentally manufactured with the angle
o-f inclination (tapered angle) being varied to three
steps, that is, 1, 1.5 and 2 and the relationship
between the tensile load and the maximum compression load
in the axial direction were determined. Test data are
shown in Table 1.
As the test method, the manufactured main body 1 was
used as a test piece, which was set to a universal material
tester, applied with an axial tensile load -from the both
ends, then compressed in the opposite direction, and the
maximum compression load was measured. The test was entrusted
to the Pre~ectural Industrial Technical Center o~ Ehime.
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Table 1
Tensile Maximum Compression Load (Kg~)
load
(Kg-~) Taper 1.0 Taper 1.5Taper 2.0
100 75 50 55
150 100 100 110
200 155 130 125
250 180 215 155
300 260 185 180
350 315 310 205
400 340 315 240.
450 385 310 280
500 ~10 390 290
55~ 555 400 365
600 540 470 3~0
When the expansion and contraction type guard baton is
actually used, the baton main body 1 is swung by a hand to
thrust out and extend the inner cylindrical member. The
extending force in this case corresponds to the tensile
load shown in Table 1. Further, -~or contracting the
extended baton main body 1, -the top end o~ the baton main
body 1 is hit and pressed, to house the inner cylindrical
member. The presslng ~orce in this case corresponds to
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the maximum compression load in Table 1. It can be seen
from the table that when the inner cylindrieal member is
thrusted out by a force corresponding, *or example, to 300
Kg-f of the tensile load, 260 Kgf of a force is required
for contracting it in a case o~ the tapered angle of 1
but it may be reduced to a force o-f 180 Kgf in a case of
the tapered angle of 2. In other words it is apparent
that a greater force has to be applied for contraction if
the tapered angle is smaller than 1 and that contraction
is difficult af-ter the cylindrical member with a smaller
tapered angle has been thrusted with a large force. On
the contrary, if the tapered an~le exceeds 2, the
compression load is further reduced and the inner cylindrical
member is contracted after it is thrusted strongly and the
functlon of the guard baton can not be attained.
Description will be made t~ t~he operation.
When a centrifugal force is applied to the baton main
body 1 by gripping the crosshandle 2 or the grip A in a
state where each o~ the cylinders 25, 26 and 27 is contained
successi~ely in a telescopic rashion (Fig. 2), the inter-
mediate cylinder 2~ and the inner cylinder 27 are thrusted
out and extended. In this case, the cylindrical outer
circumferential surface 26a of the intermediate cylinder
26 in parallel with the cylindrical axis is guided, being
in a slight plane-to-planf~ contact, along the-slide guide
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face 25c at the top end of the outer cylinder 25, and the
slide guide surface 26e at the rear end of the intermediate
cylinder 26 is guided, whlle being in a slight plane-to-
plane contact, along the cylindrical inner circumferential
surface 25b of the outer cylinder 25 in parallel with the
cylindrical axis. In the same way, the cylindrical outer
circum-ferential surface 27a of the inner cylinder 27 ln
parallel with the cylindrical axis is guided, while being
in a slight plane-to-plane contact, along the slide guide
surface 26c at the top end O-r the inner cylinder 26, and
the slide gu:Lde surface 27e at the rear end of the inner
cylinder 27 ls guided, while being in a slight plane-to-
plane contact, along the cylindrical inner circumferential
surface 26b of the intermediate cylinder 26 in parallel
with the cylindrical axis. Accordingly, the intermediate
cylinder 26 and the inner cylinder 27 can move extremely
smoothly wlth neither rattllng nor devlation. ~urther,
since the slide guide surfaces 25c, 26e, 26c and 27e are
put to plane-to-plane contact with each o-ther, their abrasion
is reduced extremely as compared with case of line-to-line
contact in the prlor art even when the baton is put to
repea-ting extending and contracting operatisn for a long
period of time, the working life can be improved greatly.
When they are completely extended, the incllned surface
26f at the rear end of $he intermediate cylinder 26 thrusted
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out of the outer cylinder 25 engages the inclined sur~ace
25d at the top end o-f the outer cylinder 25, and the
inclined surface 27f at the rear end of the inner cylinder
27 thrusted out of the intermediate cylinder 27 engages
the inclined surface 26b at the top end of the intermediate
cylinder 26 and they are retained from slipping o-ff.
Upon engagement, a strong impact is applied to the outer
cylinder 25 as the outer cylindrical member (and the inner
cylinder 26) at the inclined surface 25d (and 26d) at the
top end portion, and the component o~ the force along *he
inclined surface is exerted in the direction o-f opening
outward. In the present invention, since the outer sur-face
of the outer cylinder 25 (and the inner cylinder 26) is
made cylindrlcal as far as the top end so that the wall
thickness at the top end which was liable to suffer from
deformation in the existent structure is locally increased,
it is less de~ormed even if a large force is exerted in
the direction of openin~ outward. There-~ore, if the baton
main body 1 is thrusted out with a large force, it can be
preven*ed from slipping off. In addition, the wall thick-
ness for each of the cylindrical members can be decreased,
AS a whole, to reduce the weight.
Fig. 4 shows a modi-~ied structure of the first em-
bodiment, in which a guard portion 40 ls attached instead
of the crosshandle to the baton main body 1. The structure
3 ~ $
for expansion and contraction of the baton main body 1 is
the same as in the first embodiment.
Fig. 5 shows a portion o-~ a structure for expansion
and contraction o-f -the baton main body 1 in a second
embodiment of the present invention.
In this embodiment, a step 51 is formed between an
inner circumferential surface 25b (26b) at the top end and
the base of an inclined surface 25d (and 26d) of an outer
cylinder 25 as an outer cylindrical member (and an inter-
mediate cylinder 26), while another step 62 engageable
with the step 51 is disposed between a slide guide sur~ace
26e (27e) and an inclined surface 26-f (27~) of the interme-
diate cy~inder 26 as an inner cylindrical member (and an
inner cylinder 27). This modified embodiment has a merit
of providlng a -further improved ef-~ect -for preventing
slipping off by the engagement of the steps 51 and 52 to
each other.
Fig. 6 shows a portion o-f a third embodiment of the
present invention.
In this embodiment, a ring 55 made of an abrasion
resistant material and having a slide guide surface 25c
(26c) is attached to the top end of an outer cylinder 25
as an outer cylindrical member (and an intermediate cylinder
26). As the abrasion resistant material, titanium alloy
or like other hard metal or a synthetic resin o-~ low
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frictional resistance such as a fluoro resin is pre-ferred.
Figs. 7 and 8 show a portion for a fourth embodiment
O-r the present invention.
In this embodiment, a ring 56 made of the same abrasion
resistant mzterial as described above and having a slide
surface guide 26e 127e) is fit to the rear end of an
intermediate cylinder 26 as the inner cylindrical member
~and an inner cylinder 27) and fixed by screwing a thread-
clamping ring 57. The sliding guide surface 26e (27e) is
spherically protruded at a plurality of portions (four
portions in the illustrated embodiment) from the outer
circumferential surface of the abrasion reslstant ring 56.
Fig. 9 shows a -fifth embodiment according to the
present invention, which is dlfEerent -from the fourth
embodiment shown in Figs. 7 and 8 in that the slide guide
sur-Eace 26e t27e) of the abrasion resistant ring 59 is formed
as a cylindrical surface.
Each of the third to fi-fth embodiments has a merit
capable of outstandingly impro~ing the durability by
-forming the sllde guide surface with the abrasion resistant
material separately from the cylindrical member.
Although not illustrated in the drawings, the inner
surfaces of the outer cylinder 25 as the outer cylindrical
member and the intermediate cylinder 26 and the outer
sur-faces of the intermediate cylinder 26 and the inner
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cylinder 27 as the inner cylindrical member may be formed
with an abrasion resistant layer, for example, by applying a
nitriding treatment or a coating with a titanium alloy
layer, for improving the durability.
As has been described above, in the expansion and
contraction type guard baton according to -the present
invention, since a slide guide surface is -formed at each
of the ends of the inclined surfaces of the outer
cylindrical member and the adjacent inner cylindrical
member along which they are engaged, in a plane-to-plane
contact with the circumferential surface of the cylindrical
member, lt can provide an advantageous effect of providin~
an extremely smooth e~tendlng and contracting operation
and reducing abrasion at the end of the inclined surface
even a~ter repeating use, thereby ~reventing rattling or
dev:lation for a long period of time. Further, since the
abrasion resistance of the slide guide surface and the
contact surface thereof is enhanced, it can provide an
effect capa~le of outstandingly improving the durability
as compared ~ith the existent structure. Further, since
the outer sur~ace a* the top end of the outer cylindrical
member is formed cylindrically and the inner surface thereof
is disposed with the conicall~ inclined surface tapered
toward the top end and a cylindrical slide guide surface
in contiguous to the top end of the conically inclined
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surface, thereby increasing the wall thickness locally at
the top end, it can provide an advantageous effect that
the top end of the outer c~lindrical member is less opened
upon extension, thereby preventing the inner cylindrical
member from slipping off even if a strong impact is applied
to the top end of the outer cylindrical member. Further,
since the steps are formed at the engaging portion between
the inner and the outer cylindrical members thereby restricting
the angle of inelination for each of the inclined surfaces,
this can provide a fur-ther improved anti-slip off effect.
In part:lcular, when the structure for expansion and
eontraetion o~ the present invention is applied to a guard
baton with a crosshandle, it can provide a su-fficient
rigidity in the extended state of the guard baton $o
attain hlgh reliability.
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