PNEUMATIC VALVES
TECHNICAL FIELD
This invention relates to pneumatic valves particularly for controlling the inflow and outflow of air into and out of a self inflating cushion. In particular the invention relates to a deformable cushion having a seating surface, a self inflating cushion bladder positioned beneath the seating surface and where the self inflating cushion contains a compressible material and features an automatic pneumatic valve. BACKGROUND ART
Existing self inflating adjustable seat cushions are designed to mould exactly to individual body shapes and provide postural support and comfort with the use of manually operated mechanical and electrical valve systems to allow ingress and egress of air. Manually operated systems allow individual adjustment, particularly where a chair is frequently used by the same person. However, a manually operated system is not always suitable for use in many types of chairs as found in reception areas, conference centres, auditoriums, meeting rooms and transport, where the sitter may not be aware of the existence or benefits of a manually operated valve system or its method of operation.
Furthermore, it would be preferable for the self inflating seat cushion to reinflate (reset) after the chair is vacated and before it is reoccupied by a different person.
An automatic system is therefore more appropriate for use in such chairs, to facilitate correct rotation of the pelvis and provide postural support and comfort without a need for manual operation. DISCLOSURE OF INVENTION
It is an object of the invention to provide a valve for a self inflating cushion that automatically closes after air is displaced from the self inflating cushion bladder in which the valve is incorporated, to partially deflate the bladder containing compressible material allowing it to mould to the seated person's body shape and facilitate correct rotation of the pelvis and provide postural support. A second object of this invention is to provide a means for reinflating the self inflating cushion after the seat into which it is incorporated is vacated. According to one aspect of the invention there is provided a pneumatic cushion comprising:-
(a) a deformable cushion having a seating surface,
(b) a self inflating cushion bladder positioned beneath the seating surface, the self inflating cushion bladder comprising i. an airtight envelope ii. compressible material contained within the airtight envelope
(c) an automatic pneumatic valve comprising:
(i) a valve base having a passageway therethrough, a valve seat around the passageway, and a resilient seal in the valve seat,
(ii) a valve pressure pad overlying the valve base having a valve member adapted to engage the resilient seal, wherein the valve pressure pad is biased away from the valve base such that when there is pressure applied to the valve pressure pad by the compressible material in the airtight bladder as a result of pressure applied to the seating surface the valve member and resilient seal come into contact with each other and seal the valve and when the pressure is removed from the valve pressure pad the valve pressure pad returns to its biased position which opens the valve by lifting the valve member from the resilient seal in the valve seat. According to further aspect of the invention there is provided an automatic pneumatic valve for use in a self inflating cushion bladder incorporating compressible material, the automatic pneumatic valve comprising:-
(a) a valve base having a passageway therethrough, a valve seat around the passageway, and a resilient seal in the valve seat,
(b) a valve pressure pad overlying the valve base having a valve member adapted to engage the resilient seal, , wherein the valve pressure pad is biased against the valve base such that when there is pressure applied to the valve pressure pad the valve member and resilient seal come into contact with each other and seal the valve and when the pressure is removed from the valve pressure pad the valve pressure pad returns to its biased position which opens the valve by lifting the valve member from the resilient seal in the valve seat.
The valve pressure pad is biased away from the valve base by the inclusion of a biasing member between the valve base and the valve pressure pad.
In an alternative embodiment, the valve pressure pad has an integral biasing mechanism.
Preferably, the biasing member may be comprised of compressible foam or annular metal spring and the valve pressure pad further comprises air passages for the ingress and egress of air through the valve pressure pad.
In an alternative embodiment, the biasing member is a coil spring. In a still further alternative embodiment the biasing member is a flat beam spring.
Still more preferably the resilient seal is an O-ring and the valve member is a conical valve member for engaging the O-ring. In a still further preferable embodiment of the invention the valve further comprises guide members for retaining biasing members in place.
Preferably the guide members comprise downwardly extending flanges and upwardly extending collar.
According to a further aspect of the invention there is provided an automatic pneumatic valve for use in a self inflating cushion bladder incorporating compressible material, the automatic pneumatic valve comprising:-
(a) a valve base having a passageway therethrough, a valve seat around the passageway, a collar surrounding the valve seal and an O-ring seal in the valve seat,
(b) a valve pressure pad overlying the valve base having a valve member adapted to engage the O-ring seal, a downwardly extending flange surrounding the valve member adapted to co-operate with the collar on the valve base, and (c) a compressible foam member between the valve base at the valve pressure pad normally biasing the conical valve member away from the O-ring seal.
According to a further aspect of the invention there is provided an automatic pneumatic valve for use in a self inflating cushion bladder incorporating compressible material, the automatic pneumatic valve comprising:- (a) a valve base having a passageway therethrough, a valve seat around the passageway, a collar surrounding the valve seal and an 0-ring seal in the valve seat,
(b) a valve pressure pad overlying the valve base having a valve member adapted to engage the O-ring seal, a downwardly extending flange surrounding the valve member adapted to cooperate with the collar on the valve base, and
(c) a coil spring between the valve base at the valve pressure pad normally biasing the conical valve member away from the O-ring seal.
According to a further aspect of the invention there is provided an automatic pneumatic valve for use in a self inflating cushion bladder incorporating compressible material, the automatic pneumatic valve comprising:- (a) a valve base having a passageway therethrough, a valve seat around the passageway and an O-ring seal in the valve seat,
(b) a valve pressure pad overlying the valve base having a conical valve member adapted to engage the O-ring seal and a collar around the conical valve member adapted to engage the valve base when the valve is closed, and
(c) a beam type spring mounted by its ends on the valve base and connected by its central portion to the valve pressure pad, the beam type spring normally biasing the conical valve member away from the O-ring seal and deformable upon pressure being applied to the valve pressure pad to move the conical valve member towards the O-ring seal. According to a further aspect of the invention there is provided an automatic pneumatic valve for use in a self inflating cushion bladder incorporating compressible material, the automatic pneumatic valve comprising:- (a) a valve base having a passageway therethrough, a valve seat around the passageway and an O-ring seal in the valve seat, (b) a valve pressure pad overlying the valve base, and wherein the valve pressure pad further comprises a hairpin type spring having a lower portion and an overlying upper portion, the lower portion having an aperture that surrounds the valve seat and the upper portion having a valve plunger adapted to engage the O-ring seal, the upper portion of the hairpin spring normally biasing the valve plunger away from the O-ring seal and being deformable upon pressure being applied to the valve pressure pad to move the valve plunger towards the O-ring seal.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings in which:- Fig.1 is an exploded cutaway view of a first embodiment of the invention,
Fig. 2 is a side sectional view of the first embodiment of the invention taken along Section A-A of Fig. 3,
Fig. 3 is a top plan view of the first embodiment of the invention, Fig. 4 is an exploded view of a pneumatic valve according to a second embodiment of the invention,
Fig. 5 is a cutaway view of the valve shown in Fig. 4 in its open position, Fig. 6 is a cutaway view of the valve shown in Fig. 4 in its closed position,
Fig. 7 is an exploded view of a pneumatic valve according to a third embodiment of the invention, Fig. 8 is a perspective view of the valve shown in Fig. 7 in its open position,
Fig. 9 is a perspective view of the valve shown in Fig. 7 in its closed position.
Fig. 10 is a cutaway exploded view of a pneumatic valve according to a fourth embodiment of the invention,
Fig. 11 is a plan view of the valve shown in Fig. 10,
Fig. 12 is a cross-sectional view taken along lines A-A of Fig. 11 ,
Fig 13 is a perspective view of an annular spring,
Fig 14 is a an exploded cutaway view of the first embodiment of the invention incorporating a annular metal spring,
Fig 15 is a partial cutaway side view of a pneumatic cushion incorporating the automatic pneumatic valve of the first embodiment incorporating a compressible foam member and showing the cushion system in its inflated state before use, Fig 16 is a partial cutaway side view of a pneumatic cushion incorporating the automatic pneumatic valve of the first embodiment incorporating a compressible foam member and showing the cushion system in its partially deflated state during use, and
Fig 17 is a partial cutaway side view of a pneumatic cushion incorporating the automatic pneumatic valve of the first embodiment incorporating a compressible foam member and showing the cushion system in its inflated state after use. MODES FOR CARRYING OUT THE INVENTION
The pneumatic valve 10 shown in Fig. 1 includes a valve base 11 and an overlying valve pressure pad 12. The valve base 11 has a passageway 13 therethrough having a valve seat 14. A collar 15 surrounds the valve seat 14. An outer annular flange 17 provides a means of attaching the valve to the underside of a self inflating cushion bladder using a welding process or an adhesive.
The valve pressure pad 12 has conical valve member 20 adapted to engage an O-ring seal 16. The valve pressure pad 12 also has two downwardly extending flanges 18 and 21 which are adapted to ensure correct engagement between the valve member 20 and the O-Ring 16.
Referring to Fig 2, downwardly extending flange 21 and collar 15 and adapted to engage each other and define, along with, passageway 13 and air passageways 22 a central air passageway through which is adapted to allow the ingress and egress of air from the self inflating cushion bladder that it is mounted in.
An annular compressible foam member 100 (which may be replaced by an annular metal compression spring 120 of Fig 13 as shown in Fig. 14) is located between the valve base 11 and valve pressure pad 12, and outside of collar 15. The compressible foam member 100 does not need to be annular and can be any size or shape that is adapted to bias the conical valve member 20 away from the O-ring seal 16.
Figs 15 to 17 show the sequence of events when a person sits on a pneumatic cushion incorporating a self inflating cushion bladder positioned beneath the seating surface of the pneumatic cushion and where the pneumatic cushion contains an automatic pneumatic valve in accordance with the present invention. The pneumatic cushion 150 in this case is comprised of a self inflating cushion bladder comprising airtight envelope 125 containing a compressible material 130 such as open celled foam, and wherein the airtight envelope 125 is contained within a cavity formed in pneumatic cushion 150 having a seating surface 120. Depicted in the figures in the wall of airtight envelope 125 is the valve of Fig. 1 in which valve pressure pad 12, valve base 11 , passageway 13 and compressible foam member 100 are shown.
As shown in Fig 15, when no person is seated on the seating surface 120 the valve pressure pad 12 is biased away from the valve base 11 by compressible foam member 100. This results in passageway 13 being open. As soon as someone sits on the cushion, air is expelled through passageway 13 in the direction indicated by the large arrow in Fig. 15.
As shown in Fig. 16, as soon as someone sits on the pneumatic cushion 150 the compressible material 140 and compressible material 130 become compressed. As a result of this compression, pressure is applied to the valve pressure pad 12 by the compressible material 130 contained within the self inflating cushion bladder, in which the valve is mounted. As a result of the pressure exerted on the pressure pad 12 the bias of the compressible foam member 100 is overcome so that the conical valve member 20 (not shown) seals against the O-ring seal 16 (not shown) so as to close the valve when sufficient air has been displaced from the self inflating cushion bladder in which the valve 10 is incorporated and the seating surface 120 has moulded to the seated person's body shape to facilitate correct rotation of the pelvis and provide postural support.
As shown in Fig. 17, when the seat is vacated, the pressure exerted by compressible material 130 on the pressure pad 12 is relieved and the pressure pad 12 resumes its biased position as a result of the action of compressible member 100. In this state air can flow back through passageway 13 into the airtight envelope 125.
In an alternate embodiment depicted in Figs. 10, 11 and 12 the compressible foam member 100 is replaced with a coil spring 23 in valve 110. The coil spring 23 is located within the collar 15 of the valve base 11 and normally biases the conical valve member 20 away from the O-ring seal 16. When pressure is applied to the valve pressure pad 12 by a person sitting on the self inflating cushion as described with respect to the embodiment depicted in Figs. 10-12 the bias of the spring 23 is overcome so that the valve member 22 seals against the O-ring seal 16 so as to close the valve 10 when sufficient air has been displaced from the self inflating cushion bladder in which the valve is incorporated and the bladder has moulded to the seated person's body shape to facilitate correct rotation of the pelvis and provide postural support. The automatic pneumatic beam valve 40 shown in Fig. 4 includes a valve base 41 having a passageway 42 therethrough, and a collar valve seat 43 around the passageway 42 and an O-ring seal 44 which seats in the valve seat 43. A valve pressure pad 45 overlying the valve base 41 has, as can be seen in Figs. 5 and 6, a conical valve member 46 adapted to engage the O-ring 44, a collar 47 around the conical valve member 46 which is adapted to engage the valve base 41 when the valve 40 is closed as shown in Fig. 6.
A beam type spring 48 is mounted on the valve base 41 by means of slots 49 at each end which receive the projections 50 on the mountings 51.
The beam type spring 48 is also mounted on the valve pressure pad 45 by means of the aperture 52 which sits above the collar 47. The valve base 41 has a peripheral flange 53 by means of which it is secured to a self inflating cushion. The upper surface of the valve base 41 has posts 54 to prevent excessive pivotal movement of the valve pressure pad 15 about the axis of the beam type spring 48.
The normally open position of the valve 40 is shown in Fig. 5 and air can flow between the valve base 41 and the valve pressure pad 45 and through the passageway 42. When downward pressure is applied to the valve pressure pad 45 (in the manner described with reference to pressure pad 12 of the alternate embodiments of the invention) the conical valve member 46 engages and seals against the O-ring seal 44 and at the same time the beam type spring 48 is deflected downwardly as shown in Fig. 6. When pressure is released from the valve pressure pad 45, the beam type spring 48 returns the valve pressure pad 45 to the open position as shown in Fig. 5.
The automatic pneumatic valve 70 shown in Figs. 7 to 9 includes a valve base 71 having a passageway 72 therethrough, a valve seat 73 around the passageway 72 and a collar 74 around the valve seat 73. The O-ring seal 75 seats in the valve seat 73.
The hairpin type spring 76 has a lower portion 77 and an overlying upper portion 78. The lower portion 77 has an aperture 79 for receiving the collar 74 of the valve base 71.
A valve plunger 80 has an upper mounting plug 81 which extends through aperture 83 where it is attached or fixed to the upper portion 78 and a conical valve seat 82 which engages the O-ring seal 75. The valve 70 is shown in its open position in Fig. 8 and its closed position in Fig. 9. Upper portion 78, when fixed to valve plunger 80 acts as a pressure pad or alternatively a separate pressure pad can be fixed to its upper surface to receive the pressure in order to actuate the valve in the manner described with reference to pressure pad 12 of the alternate embodiments of the invention. The mode of operation is substantially similar to that of the earlier described embodiments. A locking mechanism comprising lock member 120 and aperture 130 are shown in respect of the first and fourth embodiments in Figs. 1 , 2, 3, 10, 11 and 12 and 14. In these embodiments the aperture 130 of pressure pad 12 is placed over the lock member 120 of valve base 11 and rotated until the pressure pad 12 is secured or locked.
Various modifications may be made in details of design and construction without departing from the scope and ambit of the invention. In particular, various parts of the present valves, such as the O-ring seal, can be substituted by over moulding or inserting a resilient seal, or in the case of the embodiment described in figure 7, forming the valve plunger 80 integral with hairpin spring 76. INDUSTRIAL APPLICABILITY
The pneumatic valves as described in various forms and embodiments . in the specification automatically close after air is displaced from a self inflating cushion and provide a means for reinflating the self inflating cushion after the seat into which it is incorporated is vacated.