Hose For A Piston-Chamber Combination
A piston-chamber combination comprising an elongate chamber which is bounded by an inner chamber wall, and comprising a piston in said chamber to be engagingly movable relative to said chamber wall at least between a first longitudinal position and a second longitudinal position of the chamber, said chamber having cross-sections of different cross-sectional areas and differing circumferential lengths at the first and second longitudinal positions, and at least substantially continuously different cross-sectional areas and circumferential lengths at intermediate longitudinal positions between the first and second longitudinal positions, the cross-sectional area and circumferential length at said second longitudinal position being smaller than the cross-sectional area and circumferential length at said first longitudinal position, said chamber is comprising an exit valve, which is communicating with a hose, which is communicating with a valve between the other end of said hose and an object to be inflated. This is achieved by the size of the volume of said hose between said valves is variable.
Latest NVB International UK Ltd. Patents:
A piston-chamber combination comprising an elongate chamber which is bounded by an inner chamber wall, and comprising a piston in said chamber to be engagingly movable relative to said chamber wall at least between a first position and a second position of the chamber,
-
- said chamber having cross-sections of different cross-sectional areas and differing circumferential lengths at the first and second positions, and at least substantially continuously different cross-sectional areas and circumferential lengths at intermediate positions between the first and second positions, the cross-sectional area and circumferential length at said second position being smaller than the cross-sectional area and circumferential length at said first position, said chamber is comprising an exit valve, which is communicating with a hose, which is communicating with a valve between the other end of said hose and an object to be inflated.
This invention deals with solutions for optimal pumping conditions, for piston-chamber combinations of any kind, but specifcially when the main part of the wall of the chamber is not parallel to the centre axis of said chamber.
An expansion room is normally used for e.g. high pressure bicycle pumps, in order to make a kind of balance between the bigger flow rate of the pump in relation to the smaller volume of the tyre to be inflated. Said expansion room is a cavity where its inlet is communicating with the exit of the chamber of a pump, through a valve. The exit of said expansion room may be directly communicating with a hose, which is connected to the valve of the object to be inflated, such as a tyre.
However, when a low pressure tyre is to be inflated, there is already a balance, because the tyre valve is opening quite early, in relation to the time it takes to finalize a pumping stroke. Thus, it is unnessary, and when a universal bicycle pump is used, such an expansion room is to be omittet.
OBJECT OF THE INVENTIONThe object is to provide an optimalisation of the functionning of any kind of a combination of a piston and a chamber, and in particular as a pump.
SUMMARY OF THE INVENTIONIn the first aspect, the invention relates to a combination of a piston and a chamber, wherein: said chamber is comprising an outlet valve, which is communicating with a hose, which is communicating with an object to be inflated, which is comprising an inlet valve, the size of the volume of said hose between said valves is variable.
Any type of chamber for a pump may be used in combination with a hose, including elongate longitudinal chambers, with different cross-sectional area's, and differing or equal circumferences between a first and second position of said chamber(s), wherein a first position has the biggest cross-sectional area, and a second longitudinal position the smallest in a transversal cross-section of said chamber, as disclosed e.g. in EP1179140B1.
The initial volume of a hose my be defined by the size of the cylinder (length of said cylinder and radius of the cross-sectional area in a transversal cross-section) when produced, thus pressurized. The hose may also have various different radii between a 1st and 2nd chamber position, as produced.
Of course may it also be possible that the hose is comprising one of both above mentioned valves.
In a second aspect the invention relates to a combination of a piston and a chamber, wherein the hose may change its volume by expansion.
When a pressure source, e.g. said chamber is comprising an outlet valve communicating with a first end of said hose, and said hose is communicating with an object to be inflated at its other end, and said inlet valve is closed, said size of the volume of said hose may increase, when fluid is entered from said outlet valve. Depending on the type of reinforcement, as e.g.
- 1. windings around the cavity of the hose, may the hose
- not change its volume, when the angle between the tangent of a reinforcement winding and the centre line of the hose (=so-called braid angle) is 54°44′.
- change its length, when said angle is bigger than 54°44′.
Changing the length of a hose (in longitudinal direction), may be an innovative feature, but in practise possibly less attractive, due to its odd behaviour.
- 2. at least a part of the hose may comprising an inflatable container type piston, which may have a shape of a cylinder, as produced, and which may be equipped with a reinforcement which normally is used in a container type piston of which the shape is changing toward the shape of an ellipsoide, or even a sphere, thus, a changing of a radius of a transversal cross-sectional area. Such a piston is described below.
EP 1 179140 B1 shows an inflatable container piston type, while EP 1 384 004 B1 shows that this piston type should have an unstresed production size wherein its circumference at the second longitudinal position of an elongate chamber, should have a circumference which is approximately the same as the one of the chamber, so as to avoid that the piston is jamming when moving from a first to a second longitudinal position.
The piston is expanding when moved from a second to a first longitudinal position. EP 1 384 004 B1 shows that a reinforcement for such a desired behaviour may be a layer where the reinforcement strengs are laying parallel besides each other in an unstressed production model, and these strengs are connecting the two end parts, of which one is mounted on the piston rod, while the other lean glide of the piston rod—the rubber is directly vulcanized on both ends. The reinforcemnet layer is the inner layer, while another, thicker layer than the layer with reeinforcement strengs, is protechting said reinforcement layer. Both layers are being vulcanized on each other, and at the end parts, there may be another extra layer on top of the two. The function of the second layer is additionally to avoid that the reinforcement strengs are ‘sticking’ out of the outer layer, thereby making a sealingly contact with the wall of the chamber impossible—however, for an engagingly contact is this just fine. Hacving the second layer on top of the reinforcement layer is working fine in practise, and it has shown be possible to expand near the 330%, e.g. in a chamber of a pump (please see WO 2008/025391) where the max. force on the piston rod is constant, from an φ17 mm (2nd longitudinal position) to an φ 59 mm (1st longitudinal position). With two reinforcment layers on top of each other with a very small angle for overlapping each other, and on top the above mentioned ‘second’ layer makes the container more strong, but expansions possible are much less 330%.
The types of rubber of the layers rubber may be different, but should be compatibel so, that these can be vulcanized on each other, without getting lose from each other under normal working conditions.
It was observed that when the ellipsoide shaped container type piston was expanding completely to its sphere shape, the chance of breaking apart was very present—that is why the design may be changed so that the length of the piston as unstressed production model be increased, by keeping the other variables, such as the chamber design unchanged—thus, the sphere shape may not be reached and neither an expansion to 330%, only an ellipsoïde which has almost become the shape of a sphere—this makes the piston reliable, even with one layer with reinforcements. The shape of the container in an unstressed production state may also be that the wall of the container is not parallel with the centre axis, but parallel to the wall of the chamber because the wall of the chamber at a second longitudinal position is not parallel to the centre axis. Just the wall of the chamber is free of the wall of the container in said unstressed production state.
Also an inflatable sphere piston may be used as a temporary expansion vessel, and such a piston has been described in e.g. EP1179140B1 and EP 1384004B1.
In a third aspect, the invention relates to to a combination of a piston and a chamber, wherein: said exit is communicating with a hose, the hose is comprising a check valve.
The hose may comprise a build in check valve. This may be classic ball check valve inside a cylinder, which is mounted in the hose—the pressure of the inner wall of the hose keeps the check valve in place. This may also be a hose, which is expandable on a small length, so that unstressed the channel inside the wall of the hose is closed, and while stressed is open.
In a fourth aspect, the invention relates to a combination of a piston and a chamber, wherein: said expandable expansion chamber is expanding from a certain pre-destinated pressure inside said hose, and is imploding by decreasing pressure rates.
The expansion of e.g. a part of the hose may enable the creation of a temporary expansion vessel. Temporary, because it is only created when there is a flow from the chamber, while the valve nearest the object to be inflated still is closed. When said hose is disconnected from the valve belonging to the valve of the object to be inflated, and there is a direct communication to the atmosphere, the internal pressure in said hose may decrease rapidly, and by that, the expanded wall of the hose may implode, resulting again in a cylinder shaped hose. And depending on e.g. the stiffness of the flexible material of the hose, and the number of layers of reinforcement, and the angle in between said laywers, this temporary expansion vessel may be created firstly when a certain pressure level has been created. This is e.g. important for the efficiency of pumping with a universal bicycle pump, with which low (low pressure, relatively high volume) and high pressure tyres (high pressure, low volume) may be inflated. And, the stroke volume of a pump with an expansion vessel, e.g. as part of the chamber at a second longitudinal position, may be less that that of a pump which is using the bottom part as part of the stroke volume, while using an expandsion vessel as part of the hose.
In order to optimize the pumping speed, the hose of a bicycle pump may be expandable upon a certain pressure, so that an expansion vessel is created there. That means that the pump is pumping very efficiently at low pressures, where the hose is not creating an expansion vessel—such a pressure vessel creates more volume to the volume of the tyre alone, to be pumped. Most of the pumping is done for low pressure tyres.
In a fifth aspect, the invention relates to a combination of a piston and a chamber, wherein: said expandable expansion vessel or chamber is comprising an stopper for maximizing the expansion of the wall of said hose.
The expansion of the hose may be limited by a reinforcement of the hose, and the expansion may be done only on a part of the hose. Additionally, there may be a stopper, e.g. a metal wire, postioned in the channel of said hose, said wire as been vulcanized to two parts of the wall inside said piston, there where the radius in a transversal cross-section is biggest—when a maximum expansion has been reached, may the wire a be a straight line.
Said hose may be used besides in pumps, additionally in actuators, shock absorbers and motors.
In the following, preferred embodiments of the invention will be described with reference to the drawings wherein:
This is a preferred embodiment for very high pressures (e.g. 16 Bar), and when the piston has difficulties in sealing to the inner chamber wall at second longtudinal positions. This construction avoids the sealing on the transition from a longitudinal cross-sectional section with a convex wall to a longitudinal cross-section section with a concave wall.
Claims
1. A piston-chamber combination comprising an elongate chamber which is bounded by an inner chamber wall, and comprising a piston in said chamber to be engagingly movable relative to said chamber wall at least between a first position and a second position of the chamber,
- said chamber having cross sections of different cross-sectional areas and differing circumferential lengths at the first and second longitudinal positions, and at least substantially continuously different cross-sectional areas and circumferential lengths at intermediate longitudinal positions between the first and second longitudinal positions, the cross-sectional area and circumferential length at said second longitudinal position being smaller than the cross-sectional area and circumferential length at said first longitudinal position,
- said chamber is comprising an exit valve, which is communicating with a hose, which is communicating with a valve between the other end of said hose and an object to be inflated, wherein the size of the volume of said hose between said valves is variable.
2. A piston-chamber combination comprising an elongate chamber which is bounded by an inner chamber wall, and comprising a piston in said chamber to be engagingly movable relative to said chamber wall at least between a first longitudinal position and a second longitudinal position of the chamber, said chamber having cross-sections of different cross-sectional areas and equal circumferential lengths at the first and second longitudinal positions, and at least substantially continuously different cross-sectional areas and equal circumferential lengths at intermediate longitudinal positions between the first and second longitudinal positions, the cross-sectional area at said second longitudinal position being smaller than the cross-sectional area at said first longitudinal position,
- said chamber is comprising an exit valve, which is communicating with a hose, which is communicating with a valve between the other end of said hose and an object to be inflated, wherein the size of the volume of said hose between said valves is variable.
3. The piston-chamber combination according to claim 1, wherein said piston is sealingly movable relative to said chamber wall.
4. The piston-chamber combination according to claim 1, wherein said hose is expandable.
5. The piston-chamber combination according to claim 6, wherein the expansion is in the longitudinal direction of said hose.
6. The piston-chamber combination according to claim 6, wherein the expansion is in the transversal direction of said hose.
7. The piston-chamber combination according to claim 5, further comprising an inflatable flexible piston, said piston is expanding when said hose is being pressurized.
8. The piston-chamber combination according to claim 5, wherein the expansion initiates from a defined pressure inside said hole, and is imploding by a decreasing pressure rate.
9. The piston-chamber combination according to claim 5, further comprising means for limiting the expansion, wherein said expandable expansion chamber is comprising a stopper.
10. The piston-chamber combination according to claim 1, wherein said hose includes reinforcing, which when unpressurized closes a channel inside the hose, and when pressurized open said channel.
11. The piston-chamber combination according to claim 2, wherein said piston is sealingly movable relative to said chamber wall.
12. The piston-chamber combination according to claim 1 claims 1-5, wherein said hose is expandable.
13. The piston-chamber combination according to claim 5, further comprising an inflatable flexible piston, said piston is expanding when said hose is being pressurized.
14. The piston-chamber combination according to claim 6, wherein the expansion initiates from a defined pressure inside said hole, and is imploding by a decreasing pressure rate.
15. The piston-chamber combination according to claim 6, further comprising means for limiting the expansion, wherein said expandable expansion chamber is comprising a stopper.
16. The piston-chamber combination according to claim 2, wherein said hose includes reinforcing which when unpressurized closes a channel inside the hose, and when pressurized opens said channel.
Type: Application
Filed: Jul 5, 2012
Publication Date: Jan 3, 2013
Applicant: NVB International UK Ltd. (Reading)
Inventor: Nicolaas VAN DER BLOM (Reading)
Application Number: 13/542,055
International Classification: F04B 41/02 (20060101); F04B 45/06 (20060101);