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EP 0 092 987 B1 |
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EUROPEAN PATENT SPECIFICATION |
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Mention of the grant of the patent: |
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02.12.1987 Bulletin 1987/49 |
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Date of filing: 22.04.1983 |
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International Patent Classification (IPC)4: F15B 15/06 |
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Rotary fluid pressure actuator
Druckmittelbetätigter Drehantrieb
Dispositif rotatif à pression de fluide
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Designated Contracting States: |
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AT BE CH DE FR GB IT LI LU NL SE |
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Priority: |
24.04.1982 ES 264705
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Date of publication of application: |
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02.11.1983 Bulletin 1983/44 |
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Applicants: |
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- Triado-Isern, Joaquin
Figueres
Girona (ES)
- Cantenys-Soler, Fermin
Figueres
Girona (ES)
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Inventors: |
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- Triado-Isern, Joaquin
Figueres
Girona (ES)
- Cantenys-Soler, Fermin
Figueres
Girona (ES)
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Representative: Carter, Gerald et al |
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Arthur R. Davies & Co.
27 Imperial Square Cheltenham, Gloucestershire GL50 1RQ Cheltenham, Gloucestershire GL50 1RQ (GB) |
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Note: Within nine months from the publication of the mention of the grant of the European
patent, any person may give notice to the European Patent Office of opposition to
the European patent
granted. Notice of opposition shall be filed in a written reasoned statement. It shall
not be deemed to
have been filed until the opposition fee has been paid. (Art. 99(1) European Patent
Convention).
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[0001] The invention relates to a mechanism for turning a shaft, the said mechanism being
of the type comprising a chamber within which a pair of pistons are oppositely movable,
each piston being provided with a toothed arm forming a rack engageable with a shaft
crossing the said chamber and arranged to be turned, the walls of the chamber being
provided with holes to allow the circulation of a fluid for exerting a pressure against
the faces of the two pistons, to move them in one or other direction.
[0002] Up to the present, in mechanisms of the described type, in order that the chamber
could be as small as possible, and at the same time the pistons could perform a stroke
as long as possible, the front plates or portions of the latter had to have the smallest
possible thickness. Although this condition involved an improvement in the length
of the stroke, prejudicial vibrations simultaneously appeared, to the detriment of
efficient and operational life of the mechanism.
[0003] Prior Patent Specification WO-A-80/01 096 discloses a rotary actuator having opposite
stroke pistons having racks thereon and hollow spaces in the ends of the pistons remote
from the racks for the mounting of helical springs.
[0004] It is the object of this invention to provide an improved mechanism of the type referred
to for turning a shaft which is not subject to the disadvantages of the prior art,
while achieving useful and reliable operation.
[0005] In accordance with the present invention there is provided a mechanism for turning
a shaft comprising a body defining a chamber, the shaft extending across the chamber
and projecting from the body, a pair of oppositely disposed pistons movable within
the chamber towards and away from one another, the shaft extending between the pistons,
each piston including an axially extending toothed arm forming a rack portion, said
toothed arm having a hollow structure and being at least partly shaped to conform
with the contour of the interior of the chamber, said rack portions meshing with a
pinion on the shaft, so that movement of the pistons, under the influence of fluid
pressure, results in turning of the shaft, and each piston having, on its face opposite
to its toothed arm, several hollow spaces for receiving respective helical springs,
characterised in that each toothed arm comprises a first portion projecting from the
respective piston and having a hollow structure reinforced by equidistantly distributed
walls and being adapted to the inner contour of the chamber; that said toothed arm
comprises a second substantially flat and toothed portion projecting axially from
said first portion; that each piston comprises a hollow structural projecting portion
being adapted to the inner contour of the chamber and arranged to engage the first
portion of the toothed arm of the other piston when the pistons reach the nearest
position to each other, and that each piston is provided with a slot to receive the
free end of the second portion of the toothed arm of the opposite piston when the
pistons move closely together.
[0006] By this means, it has been possible to widen the contour of the pistons, but in such
a manner that the thickness of their walls is smaller than that of the conventional
ones, so that weight reduction is achieved, the shape of said pistons is such as to
include several helical springs for applying force in opposition to the action of
fluid under pressure that acts on the pistons in the centre of the chamber.
[0007] The following is a detailed description of an embodiment of the invention, reference
being made to the accompanying drawings in which:
Figure 1 is a longitudinal section of the mechanism showing the pistons in the nearest
position to each other, and
Figure 2 is a cross section of the mechanism on the line II-II in Figure 1.
[0008] The mechanism comprises a body defining an interior generally cylindrical chamber
1. The body has ducts for entry of fluid under pressure, to the space within the chamber.
End covers 2 enclose the ends of the generally cylindrical chamber 1.
[0009] A pair of oppositely disposed pistons 3 are movably mounted within the chamber for
movement towards and away from one another. Each piston 3 has an integral hollow arm
3"' protruding eccentrically from the front of the piston 3, having a portion with
a contour of the same shape as that of the chamber interior. One of the faces of each
arm 3"' is toothed in order to form a rack toothed surface engageable with a pinion
4 formed on the shaft 5, which is transversely mounted across the centre of the chamber
1.
[0010] Diametrically opposed to the arms 3"', the pistons are provided with projecting portions
3", the contour of these also being partially shaped to conform with that of the chamber.
These are staggered with respect to the arms 3"'. When the pistons reach their nearest
positions to each other, the said portions co-operate with corresponding hollow portions
formed in the said arms 3'".
[0011] The hollow spaces of the arms 3"', as well as the projecting portions 3", are reinforced
by several equidistant vertically arranged walls 7. Several hollow spaces 8 are also
formed in opposite faces of the pistons, said spaces 8 being arranged for operative
mounting of respective helical springs. This arrangement is specially devised for
mechanisms of the type described in which fluid under pressure is only received, as
previously indicated, through a point in the middle of the chamber, but where the
mechanism is designed to receive fluid for application to both the front and rear
of the pistons, the springs may be omitted. The hollow spaces 8 then serve to reduce
the weight of the pistons, in spite of their enlarged contour width. The pistons are
each provided with an enlarged slot 9 to accommodate the end of the toothed arm 3"'
on the opposite piston, thus substantially increasing the length of the piston stroke
within the chamber.
A mechanism for turning a shaft (5), comprising a body defining a chamber (1), the
shaft extending across the chamber and projecting from the body, a pair of oppositely
disposed pistons (3) movable within the chamber (1) towards and away from one another,
the shaft (5) extending between the pistons (3), each piston (3) including an axially
extending toothed arm (3"') forming a rack portion, said toothed arm (3"') having
a hollow structure and being at least partly shaped to conform with the contour of
the interior of the chamber (1), said rack portions meshing with a pinion (4) on the
shaft, so that movement of the pistons (3), under the influence of fluid pressure,
results in turning of the shaft (5), and each piston (3) having, on its face opposite
to its toothed arm (3'''), several hollow spaces (8) for receiving respective helical
springs, characterised in that each toothed arm (3"') comprises as first portion projecting
from the respective piston (3) and having a hollow structure reinforced by equidistantly
distributed walls (7) and being adapted to the inner contour of the chamber (1); that
said toothed arm (3"') comprises a second substantially flat and toothed portion projecting
axially from said first portion; that each piston (3) comprises a hollow structural
projecting portion (3") being adapted to the inner contour of the chamber (1) and
arranged to engage the first portion of the toothed arm (3''') of the other piston
when the pistons (3) reach the nearest position to each other, and that each piston
is provided with a slot (9) to receive the free end of the second portion of the toothed
arm (3"') of the opposite piston when the pistons (3) move closely together.
Vorrichtung zum Drehen einer Welle (5), mit einem eine Kammer (1) bildenden Körper,
wobei die Welle sich durch die Kammer erstreckt und aus dem Körper hervorsteht, einem
Paar gegenüberliegenden Kolben (3), welche in der Kammer (1) aufeinander zu und voneinander
weg bewegbar sind, wobei die Welle (5) sich zwischen den Kolben (3) erstreckt, jeder
Kolben (3) einen sich axial erstreckenden, mit Zähnen versehenen Arm (3"') hat, welcher
einen Zahnstangenteil bildet, der gezahnte Arm (3"') hohl und mindestens teilweise
geformt ist, um sich der Form des Inneren der Kammer (1) anzupassen, die Zahnstangenteile
in ein Ritzel (4) auf der Welle eingreifen, so dass die Bewegung der Kolben (3) unter
dem Einfluss des Fluidumdruckes in einem Drehen der Welle (5) resultiert und jeder
Kolben (3) auf seiner dem gezahnten Arm (3"') gegenüberliegenden Seite mehrere Hohlräume
(8) zur Aufnahme entsprechender Schraubenfedern hat, dadurch gekennzeichnet, dass
jeder gezahnte Arm (3"') einen ersten Teil umfasst, welcher von dem entsprechenden
Kolben (3) vorsteht und eine Hohlstruktur hat, welche durch in gleichem Abstand verteilte
Wände (7) verstärkt ist und ausgelegt ist, um sich der inneren Form der Kammer (1)
anzupassen, dass der gezahnte Arm (3"') einen zweiten im wesentlichen ebenen und gezahnten
Teil hat, welcher axial von dem ersten Teil absteht, dass jeder Kolben (3) einen hohlen,
vorstehenden Strukturteil (3") hat, welcher der inneren Form der Kammer (1) angepasst
und angeordnet ist, um den ersten Teil des gezahnten Armes (3"') des anderen Kolbens
zu berühren, wenn die Kolben (3) ihre Stellung erreichen, in welcher sie sich am nächsten
liegen, und dass jeder Kolben mit einem Schlitz (9) zur aufnahme des freien Endes
des zweiten Teiles des gezahnten Armes (3"') des gegenüberliegenden Kolbens, wenn
die Kolben (3) sich eng aufeinander zu bewegen, versehen ist.
Mécanisme pour tourner un arbre (5), comprenant un corps définissant une chambre (1),
l'arbre s'étendant à travers ladite chambre et dépassant ledit corps, une paire de
pistons (3) disposé l'un en face de l'autre et mobiles dans ladite chambre (1) l'un
vers l'autre et l'un de l'autre, l'arbre (5) s'étendant entre les pistons (3), chaque
piston (3) comprenant un bras (3"') s'étendant axialement et pourvu de dents pour
former une partie de crémaillère, ledit bras (3"') pourvu de dents étant d'une structure
creuse et étant au moins partiellement formé pour s'adapter au contour de l'intérieur
de la chambre (1), lesdites parties de crémaillère mordant sur un pignon (4) sur ledit
arbre, de sorte que le mouvement des pistons (3), sous l'influence de pression fluide,
résultent en une rotation de l'arbre (5), et chaque piston (3) ayant, sur sa face
opposée à son bras (3"') pourvu de dents, plusieurs espaces creux (8) pour recevoir
des ressorts à boudin correspondants, caractérisé en ce que chaque bras (3"') pourvu
de dents comprend une première partie s'étendant à partir du piston (3) respectif
et ayant une structure creuse renforcée par des parois (7) distribuées de façon équidistantes
et étant adaptées au contour intérieur de la chambre (1), ledit bras (3"') pourvu
de dents comprenant une seconde partie, substantiellement plane et pourvue de dents,
s'étendant axialement à partir de ladite première partie, que chaque piston (3) comprend
une partie (3") en saillie de structure creuse adaptée au contour intérieur de la
chambre (1) et disposée pour engager la première partie du bras (3"') pourvu de dents
de l'autre piston, quand les pistons (3) atteignent leur position de plus grand rapprochement
et que chaque piston est pourvu d'une fente (9) pour recevoir l'extrémité libre de
la seconde partie du bras (3"') pourvu de dents du piston opposé, quand les pistons
(3) se déplacent très étroitement l'un vers l'autre.
