EP0219327A1 - Aufblasbare, axial zusammenziehbare Stelleinrichtung - Google Patents

Aufblasbare, axial zusammenziehbare Stelleinrichtung Download PDF

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Publication number
EP0219327A1
EP0219327A1 EP86307860A EP86307860A EP0219327A1 EP 0219327 A1 EP0219327 A1 EP 0219327A1 EP 86307860 A EP86307860 A EP 86307860A EP 86307860 A EP86307860 A EP 86307860A EP 0219327 A1 EP0219327 A1 EP 0219327A1
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EP
European Patent Office
Prior art keywords
protrusion
bladder
actuator
axially
protrusions
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP86307860A
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English (en)
French (fr)
Inventor
Guy Broer Immega
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Individual
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Individual
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Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of EP0219327A1 publication Critical patent/EP0219327A1/de
Withdrawn legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/08—Characterised by the construction of the motor unit
    • F15B15/10—Characterised by the construction of the motor unit the motor being of diaphragm type
    • F15B15/103—Characterised by the construction of the motor unit the motor being of diaphragm type using inflatable bodies that contract when fluid pressure is applied, e.g. pneumatic artificial muscles or McKibben-type actuators

Definitions

  • the present invention relates to an inflatable axially contractable actuator and an enclosure for same, inflatable in response to increasing fluid pressure.
  • Previously inflatable, contractable actuators designed for providing a selected tension force between two points include United States Patent No. 2,483,088 issued September 27, 1949 to de Haven which is composed of an inner elastomeric tube and an outer tensioning tube composed of strands interwoven on the diagonal, forming a plurality of left-handed and right-handed helices in the shape of a continuous tube. Radially directed force on the helically wound strands is provided by the inner tube in response to increasing the fluid pressure therein. Expansion of the helices translates into overall contraction and resultant tension applied to the actuator end supports.
  • United States Patent No. 2,844,126 issued July 22, 1958 to Gaylord discloses an elongated expansible bladder made of flexible elastomeric material surrounded by a woven sheath forming an expansible chamber which contracts in length when expanded circumferentially by pressurized fluid.
  • the sheath and end connectors translate radial expansion to axial force on a load.
  • de Haven arises from rubbing of the inextensible strands on the bladder. Such friction is at a maximum at the start of any contraction or extension due to the static nature of the friction and the requirement to break through this relatively high level of static friction before experiencing a lower dynamic friction.
  • elastic hysteresis occurs due to expansion of the bladder surrounded by the strands.
  • the second limitation of some foregoing devices arises because of the relatively limited amount of contraction as a percentage of the uncontracted distance between the actuator ends that such actuators can achieve.
  • the percentage contraction of the de Haven and Gaylord actuators is limited by the need to change the angle of the woven strands in the outer sheath during contraction.
  • the amount of pulling force and the percentage contraction of the axially contractable actuator is directly related to the volumetric expansion of the bladder since the work done by the actuator equals the pressure therein multiplied by the total change in volume inside the actuator.
  • the volume change inside the inextensible strands or cables is sometimes referred to as the spindle volume.
  • Yarlott, de Haven, and Gaylord refer to a requirement for only flexible material for the bladder
  • de Haven and Gaylord indicate elastomeric material as being preferable. It has been discovered that operation of devices such as de Haven and Gaylord is enhanced by the lateral forces exerted on the strands as a result of elastic expansion of the bladder between the strands. Unfortunately, the high friction forces on, and tension forces in the fabric at these locations drastically increase the likelihood of actuator failure. With the Yarlott actuator, the possible percentage contraction is limited by the ability of the bladder to accommodate radial bulging without excessive shear stress in the bladder membrane.
  • an inflatable axially contractable actuator bladder having a plurality of substantial protrusions about its periphery, characterised in that each such protrusion has a respective base having at least four sides, each base side of a protrusion is substantially straight and attached to a base side of an adjacent protrusion by a first flexible seam or continuous fold, and each protrusion is foldable about a second flexible seam or continuous fold, said second seam or fold being in a plane dividing the protrusion into two parts, from an axially-extended condition in which the protrusion encloses a reduced volume to an axially contracted condition in which the protrusion encloses a larger volume.
  • an inflatable axially contractable actuator bladder having a plurality of protrusions about is periphery, characterised in that each such protrusion has a respective base having at least four sides, each said base side of a protrusion is substantially straight and attached to a base side of an adjacent protrusion by a first flexible seam or continuous fold, and each protrusion is foldable about a second flexible seam or continous fold, said second seam or fold being in a plane dividing the protrusion into two parts, from an axially extended condition in which the base sides of the protrusion are substantially aligned thereby enclosing a reduced volume to an axially contracted condition in which the protrusion encloses a larger volume.
  • an inflatable axially contractable actuator bladder having a plurality of protrusions about its periphery, characterised in that each such protrusion is a convex polyhedron with a respective base having at least four sides, each said base side of a protrusion is substantially straight and attached to a base side of an adjacent protrusion by a first flexible seam or continuous fold, and each protrusion is foldable about a second flexible seam or continuous fold, said second seam or fold being in a plane dividing the protrusion into two parts, from an axially extended condition, in which the base sides of the protrusion are substantially aligned thereby enclosing a reduced volume to an axially contracted condition in which the protrusion encloses a larger volume.
  • an inflatable actuator bladder axially contractable along a main axis and having a plurality of protrusions about its periphery, characterised in that each such protrusion is a convex polyhedron with a respective base having at least four sides, each said base side of a protrusion is substantially straight and attached to a base side of an adjacent protrusion by a first flexible seam or continuous fold, and each protrusion is foldable about at least one second flexible seam or continuous fold, said second seam or fold being in a plane which divides the protrusion into parts and which incorporates the main axis of the bladder, from an axially extended condition in which the base sides of the protrusion are substantially aligned thereby enclosing a reduced volume to an axially contracted condition in which the protrusion encloses a larger volume.
  • an inflatable actuator bladder axially contractable along a main axis, having a plurality of protrusions about its periphery, characterised in that each such protrusion has at least four sides and an arcuate outer periphery, each said base side of a protrusion is substantially straight and attached to a base side of an adjacent protrusion by a first flexible seam or continuous fold, and each protrusion is foldable about at least one second flexible seam or continuous fold, said second seam or fold being in a plane which divides the protrusion into parts and which incorporates the main axis of the bladder, from an axially extended condition in which the base sides of the protrusion are substantially aligned thereby enclosing a reduced volume to an axially contracted condition in which the protrusion encloses a larger volume.
  • the invention further provides a bladder wherein the base sides of the protrusions are substantially aligned when the actuator is axially extended.
  • the invention further provides such a bladder wherein the protrusions are convex polyhedra.
  • the invention further provides such a bladder axially contractable along its main axis wherein each protrusion is foldable about at least one second flexible seam or continuous fold lying in a plane which divides the protrusion into parts and which incorporates the main axis of the bladder.
  • the bladder may include series of protrusions which have base sides at least one end thereof which is not adjacent an axial end of the bladder.
  • the base sides of the protrusions may be equal in number but preferably have an equal number or four or six base sides.
  • the invention further provides an inflatable actuator including a bladder and a pair of axially aligned end connectors, means for inflating the bladder and means for transmitting tension force in the material of said bladder to axial pulling force at the end connectors.
  • Provision of a plurality of protrusions articulating about their base seams and sides allows the use of substantially non-elastomeric use material for the membrane of the hollow enclosure or bladder, thereby avoiding failure problems associated with elastomeric materials.
  • the hollow enclosure or bladder is made of a flexible material. Utilizing a flexible non-elastomeric material rather than a rigid plate for the protrusions results in a more even distribution of membrane forces over the length of the base seams of the protrusions.
  • the present invention also provides an actuator as described above, further comprising a pair of axially aligned end connectors, one at each end of the bladder, means for inflating the bladder, and means for transmitting tension force in the material of said bladder to axial pulling force at the end connectors.
  • An actuator 11 shown in Figure 1 in axially-­extended form has a network of linked cables 10 which are attached to end connectors 12 and 13.
  • the axial direction extends between connectors 12 and 13.
  • the network of linked cables 10 surrounds a hollow enclosure or bladder 14 preferably made of flexible, substantially non-elastic, impermeable material which is also attached to end connectors 12 and 13.
  • the hollow enclosure 14 which protrudes through apertures of the network of linked cables 10 can accommodate fluid pressure from a gaseous or liquid medium.
  • the actuator 11 in axially-contracted form is shown in Figure 2.
  • the hollow enclosure 14, illustrated in Figures 3 and 5 without the network of linked cables 10 and end connectors 12, is preferably made from flexible, substantially non-elastic impermeable material, such as, for example, woven fibres of nylon or kevlar bonded with flexible rubber or plastic to form an impermeable membrane.
  • the hollow enclosure is in the axially-extended state, while Figure 5 shows it in the axially-contracted state.
  • a tubular nipple 32 and fittings 18 may either be external to the hollow enclosure 14 or internal thereto as shown in Figures 7 and 8.
  • the hollow enclosure 14 has preferably a shape of multiple inter­connected convex polyhedra which are in this embodiment approximate four-sided pyramids 15 joined along their basal edges 44, each pyramid having corners 46 extending from the basal edge intersections to an apex 47. The corners 46 are formed by the intersection of adjacent polyhedron faces 48.
  • the hollow enclosure embodiment shown in Figure 3 has two stages 49 and 51 along the actuator axis, each stage comprised of six four-sided pyramids each, for a total of twelve pyramids in all.
  • Other hollow enclosure configurations of more than two stages of convex polyhedra along the actuator axis and fewer than or greater than six convex polyhedra in each stage work well also.
  • FIG. 4 and 6 illustrate the network of linked cables 10 and the end connectors 12 in isolation from the hollow enclosure 14 shown together in Figures 1 and 2.
  • the network 10 is comprised of non-stretchable flexible tension links 20 which are joined together at nodes 22 so as to form four-sided diamond-shaped apertures 24 in the network.
  • the cables or tension links 20 are terminated with bulbous fittings 26 which are inserted into sockets 28 and in the end connectors 12 and 13 thus forming a strong connection.
  • Retaining ring 30 serves to hold the bulbous cable terminations 26 into the sockets 28 of the end connectors 12 and to hold the cable elements 20 next to the hollow enclosure 14 as the actuator 11 contracts axially.
  • End connectors 12 and 13 serve to transmit actuator pulling force to a load.
  • End connector 12 also serves to let liquid or gas into or out of the hollow enclosure 14 by means of orifice 16 and a nipple 32 having a hollow interior which is in fluid communication with orifice 16.
  • the network of linked cables 10 is fabricated from multiple-strand steel cables 20 joined together at the nodes 22 with metal compression ferrules. Other materials can be used for the network of linked cables 10, for example, solid wire, pivoted rigid links, joined twine, and synthetic fibres.
  • Figure 7 illustrates an alternative end connector 42 suitable for tension actuators with a cable network 10 having looped ends 34 thereof attached to the end connector body 36. Threaded cable stanchions 38 serve to transmit the pulling force from the cable elements to the end connector body 36.
  • the retainer ring 40 is internally threaded so that it can be screwed over the end connector body 36.
  • An internal termination 18 to the hollow enclosure 14 is provided for receiving a nipple 32 of the end connector 42.
  • An internal end termination of the hollow enclosure allows shortening of the total length of the actuator 11.
  • Figure 8 illustrates yet another alternative end connector 43 in which the fluid orifice 23 is at the end rather than running transversely to the axis of the actuator 14.
  • the protruding polyhedra of hollow enclosure 14 are four-faced pyramids joined to each other along their basal edges 44 by continuous folds or flexible seams 54.
  • Each face 48 of a pyramid is joined to adjacent faces 48 by flexible lateral folds or seams 55 extending along corners 46.
  • the polyhedra could be truncated pyramids as shown in Figure 10 meeting along a truncated edge 50 having lateral seams 52 and basal edges 57 rather than having lateral seams 55 and basal edges 44 as shown in Figure 9.
  • polyhedron or polyhedrol is intended to describe complex shapes having sides which are planar or substantially planar.
  • the polyhedra of hollow enclosure 14 need not be all identical nor need they be symmetrical.
  • the cable network 10 has segments or links 20 which occupy the valleys between adjacent polyhedra. They need not be attached to the hollow enclosure 14, but may optionally be attached thereto embedded in or part of the material of the hollow enclosure 14.
  • the admission through orifice 16 of fluid pressure inside hollow enclosure 14 causes the membrane of the latter to flex and accommodate an increase in volume inside enclosure 14.
  • the expansion of enclosure 14 causes the network of linked cables 10 to expand radially and contract axially as illustrated in Figure 6; thus, the linked cables 10 transfer tension of the membrane of the hollow enclosure 14 to pulling force on the end connectors 12 and 13. The same articulation occurs without the network of cables.
  • each polyhedron When the actuator 11 is fully extended, each polyhedron is preferably, collapsed to its minimum possible volume which is preferably negligible compared to its expanded volume. As actuator contraction develops, each polyhedron expands its volume by folding articulation along its lateral seams 55. In addition, the polyhedra alter their mutual orientation by folding along their common basal edges 44. The net result is an increase in both radius and total enclosure volume and a corresponding shortening of the enclosure 14.
  • the polyhedra are each dimensioned so that articulation is accompanied by only negligible change in their surface dimensions while also maintaining substantially shear-free connections to each other. Avoidance of deformation in this manner permits the enclosure to be fabricated from impermeable substantially non-elastic impregnated fabric or even from rigid hinged plates.
  • the former material is preferable inasmuch as the flexible fabric distributes tension forces over the entire surface area of the enclosure. At full expansion (actuator-contracted), the flexible fabric polyhedra tend to develop a moderately curved or conical form, and the polyhedra faces will bulge with only minimal stretching.
  • the folding articulation of the polyhedra facilitates contraction of the actuator 11 with only a relatively small change in radius of the portion of the hollow enclosure defined by the basal seams 54 from that in an extended condition to that in a contracted condition.
  • the latter radius change is small compared with the inflatable balloon-like devices having a plurality of longitudinally-­extending load bearing cables.
  • the actuator 11 is capable of achieving contractions in excess of 45%.
  • the cable network 10 constrains radial expansion of the enclosure, thereby minimizing deformation as well as relieving interpolyhedra seams of any longitudinal tension. Cable network 10 transmits a large axial force to the end connectors, thereby minimizing axial stress on the enclosure fabric at the end connectors and failure of the enclosure 14.
  • Figure 5 and Figures 15 and 16 show expanded hollow enclosures (actuator-contracted) without a network or linked cables (illustrated in Figure 6).
  • the network of linked cables is not necessary, since the tensile strength of the hollow enclosure itself is sufficient to transmit pulling forces to the ends of the actuator. Therefore, Figure 5 and Figures 15 and 16 represent further embodiments. If end connectors are employed, they may be similar to those depicted in Figures 4, 7 and 8, but without provision for terminating the cables 10, and without the retaining sleeve 30 and 40.
  • a theoretical analysis of the actuator 11 involves a force equilibrium analysis as well as an energy analysis.
  • the essential concept of force equilibrium analysis is the transformation of outward pressure force on the polyhedra faces into longitudinal tension force in the cable mesh.
  • a tension force is considered to be positive.
  • Fa is proportional to the square of Lo.
  • FIG. 15 An alternative configuration for the protrusions of an actuator bladder is illustrated in Figure 15 in which the protrusions are in the form of convex polyhedra having six faces and a four-sided base wherein the top of the polyhedra are truncated in a direction substantially parallel to the base when the polyhedra are folded flat.
  • the protrusions in Figure 15 are similar to the one illustrated in Figure 10.
  • FIG. 16 Yet another alternative configuration for the actuator bladder is illustrated in Figure 16 in which the protrusions consist of a four-sided base 72 and an arcuate periphery 74 extending from one corner of the base to a diagonally-opposite corner thereof in a direction substantially axially of the actuator.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Actuator (AREA)
EP86307860A 1985-10-11 1986-10-10 Aufblasbare, axial zusammenziehbare Stelleinrichtung Withdrawn EP0219327A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US78644085A 1985-10-11 1985-10-11
US786440 2004-02-25

Publications (1)

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EP0219327A1 true EP0219327A1 (de) 1987-04-22

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EP86307860A Withdrawn EP0219327A1 (de) 1985-10-11 1986-10-10 Aufblasbare, axial zusammenziehbare Stelleinrichtung

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EP (1) EP0219327A1 (de)
JP (1) JPS62155306A (de)
AU (1) AU6381786A (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5823511A (en) * 1995-10-12 1998-10-20 Her Majesty The Queen In Right Of Canada, As Represented By Minister Of National Defence Of Her Majesty's Canadian Government Force generation device for simulation of shoulder-supported rocket launching
WO2005031173A1 (de) * 2003-09-26 2005-04-07 Prospective Concepts Ag Pneumatischer aktor
CN112555222A (zh) * 2019-09-10 2021-03-26 通用汽车环球科技运作有限责任公司 可在多个位置中调姿态的内部张紧的可膨胀结构
IT202100024356A1 (it) 2021-09-22 2023-03-22 Fondazione St Italiano Tecnologia Dispositivo muscolo artificiale fluidico

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015509578A (ja) 2012-02-28 2015-03-30 プレジデント アンド フェローズ オブ ハーバード カレッジ 布−エラストマー複合材を空気圧式アクチュエータとして提供する装置、システムおよび方法

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3570814A (en) * 1969-02-24 1971-03-16 Mac Gregor Comarain Sa Traction cylinder

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3570814A (en) * 1969-02-24 1971-03-16 Mac Gregor Comarain Sa Traction cylinder

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5823511A (en) * 1995-10-12 1998-10-20 Her Majesty The Queen In Right Of Canada, As Represented By Minister Of National Defence Of Her Majesty's Canadian Government Force generation device for simulation of shoulder-supported rocket launching
WO2005031173A1 (de) * 2003-09-26 2005-04-07 Prospective Concepts Ag Pneumatischer aktor
CN112555222A (zh) * 2019-09-10 2021-03-26 通用汽车环球科技运作有限责任公司 可在多个位置中调姿态的内部张紧的可膨胀结构
CN112555222B (zh) * 2019-09-10 2023-08-08 通用汽车环球科技运作有限责任公司 可在多个位置中调姿态的内部张紧的可膨胀结构
IT202100024356A1 (it) 2021-09-22 2023-03-22 Fondazione St Italiano Tecnologia Dispositivo muscolo artificiale fluidico
WO2023047322A1 (en) * 2021-09-22 2023-03-30 Fondazione Istituto Italiano Di Tecnologia Fluidic artificial muscle device

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AU6381786A (en) 1987-04-16
JPS62155306A (ja) 1987-07-10

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