Negative Pressure Medical Device

Abstract

a longitudinal housing (10) having a first end (101) configured to be connected to a wound and a second end (102) opposite the first end (101), the longitudinal housing (10) being a hollow, cylindrical, single-piece structure; a piston (11) sliding within the housing (10) to generate a negative pressure; a constant force mechanism (12, 12') configured to be loaded and operated by the piston (11), the constant force mechanism (12, 12') being fixed to the piston (11) sliding at the second end (102) of the longitudinal housing (10) and being disposed within the housing (10); and a force mechanism (12, 12') configured to move when the piston (11) slides toward the first end (101) of the housing (10). a valve system (13) for drawing air from the wound fluid into the housing (10) as the piston (11) slides towards the second end (102) of the housing (10), wherein the constant force mechanism (12, 12') is entirely contained within the longitudinal housing (10) through which the piston (11) slides, and the second end (102) of the longitudinal housing (10) has a rear opening (14) that allows one or more fingers of an individual's hand to be inserted to manually slide the piston (11) and apply a load to the constant force mechanism (12, 12').

Description

[Technical Field]

[0001] The present invention relates to a medical device for treating wounds resulting from metabolic diseases such as diabetes or for treating any surgical incision. In particular, the present invention relates to a negative pressure device. [Background technology]

[0002] The inflammatory process that occurs during wound healing is characterized by excessive blood flow to the damaged tissue. Platelets tend to aggregate and form new tissue with fibroblasts, while white and red blood cells represent the so-called exudate. If the wound is exposed to microorganisms or other external pathogens, wound infection can occur, worsening the patient's condition and inevitably prolonging healing time. Therefore, removing these pathogens from the damaged tissue accelerates and improves the wound healing process.

[0003] The use of negative pressure devices to treat various types of wounds, combined with the use of electric vacuum generators, has become quite popular over the past 30 years. Negative pressure wound therapy has been shown to be highly effective in treating acute, chronic or exuding wounds, such as ulcers (pressure, diabetic or venous), surgical incisions and traumatic amputations.

[0004] The application of reduced pressure or negative pressure creates suction, which removes excess exudate from the wound, reducing the risk of maceration and infection. Additionally, negative pressure stimulates the flow of fresh, oxygenated blood to the wound area, promoting the formation of granulation tissue.

[0005] Currently, this type of device uses an electric pump to achieve a constant and appropriate negative pressure. This means that the cost of the device itself is very high. Furthermore, they have a significant negative impact from an environmental perspective. In fact, medical devices for treating wounds by suction are disposable. Therefore, for proper disposal, the electronic components must be separated from the mechanical components. Furthermore, this type of device is complex to use, limiting its use to specialized personnel.

[0006] Devices that do not use an electric pump system are known in the literature.

[0007] For example, CN202497590U (Patent Document 1) discloses a portable medical device for constant negative pressure drainage, which includes a drainage container, a piston inserted into the container, and a constant-force mechanism formed by a spring structure. To operate the piston, an additional tool (a rear slide bar) must be used to generate negative pressure.

[0008] US2019 / 0298899A1 (Patent Document 2) discloses a medical device for treating wounds that has low tolerance for pressure fluctuations and can generate a substantially constant reduced pressure. However, the effectiveness of this device is ensured by a complex system of sensors and alarms for timely detection of when the device is empty.

[0009] US2016 / 015592A1 (Patent Document 3) discloses a device for applying a small mechanical force to a wound to promote its healing. The device includes a pressure chamber with a sealing piston and a constant-force spring applied to the piston.

[0010] WO2015 / 003194A2 (Patent Document 4) discloses a fluid drainage device comprising a volume for receiving a fluid, the volume comprising a conduit and a sealed piston with the conduit, wherein the movement of the piston varies the amount of liquid suction.

[0011] US2016 / 354595A1 (Patent Document 5) discloses a valve system having three outlet connectors that are connected to a system including a syringe for aspirating a fluid.

[0012] US 6,174,306 B1 (Patent Document 6) discloses a device for sealing wounds covered with a film, which includes a drainage pipe connected to a pump system and is portable.

[0013] US2018 / 353660A1 (Patent Document 7) discloses a medical suction device having a cylindrical housing in which a piston and an elastic element slide to generate a constant force, preferably used in an operating room, to maintain constant suction.

[0014] Although known technical literature suggests the possibility of creating negative pressure devices without electric pumps, these devices are generally less effective because they are unlikely to reproduce a consistent negative pressure value comparable to that of an electric device. Furthermore, they often consist of numerous additional moving components, which makes them more complex and prone to failure. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] Chinese Patent No. 202497590U Specification [Patent Document 2] US Patent Application Publication No. 2019 / 0298899 [Patent Document 3] US Patent Application Publication No. 2016 / 015592 [Patent Document 4] International Publication No. 2015 / 003194 [Patent Document 5] US Patent Application Publication No. 2016 / 354595 [Patent Document 6] U.S. Patent No. 6,174,306 [Patent Document 7] US Patent Application Publication No. 2018 / 353660 Summary of the Invention [Problem to be solved by the invention]

[0016] SUMMARY OF THE INVENTION It is an object of the present invention to overcome, in part or in whole, the above-mentioned drawbacks of known systems and to provide a negative pressure device which is effective, safe, economical and at the same time easy to use. [Means for solving the problem]

[0017] SUMMARY OF THE INVENTION A negative pressure device for treating wounds is presented herein.

[0018] The device includes a longitudinal housing having a first end adapted to be connected to a wound and a second end opposite the first end, the longitudinal housing being a one-piece, hollow cylindrical structure.

[0019] The apparatus further includes a piston that slides within the housing to generate a negative pressure, and a constant-force mechanism configured to load and actuate the piston. Specifically, the constant-force mechanism is secured to the second end of the longitudinal housing and the sliding piston and is disposed within the housing.

[0020] The device includes a valve system that draws air from the housing when the piston slides to a first end of the housing and introduces wound fluid into the housing when the piston slides to a second end of the housing.

[0021] In particular, the constant force mechanism is entirely contained within the longitudinal housing within which the piston slides, and the second end of the longitudinal housing further includes a rear opening that allows for insertion of at least one finger of an individual's hand to manually slide the piston and apply a load to the constant force mechanism.

[0022] This allows the device of the present invention to generate and control subatmospheric pressure within the housing even without a power supply. The opening located at the second end of the housing allows the piston to be mechanically pressed in a simple manner, for example, using a finger, without relying on an additional tool such as a special actuation tool (rear bar). Furthermore, using the finger of one hand allows the user to more easily control the suction process and provides an active sensation in case the device is disconnected or there is a small leak. For example, the constant force mechanism and piston can be easily reloaded with a finger if necessary.

[0023] Furthermore, the device according to the invention is considerably cheaper and easier to manufacture than devices according to known technology, since it does not use any electronic components. Furthermore, during the disposal process, it is not necessary to separate components of different natures, and the entire device can be disposed of as special medical waste.

[0024] The constant force mechanism is completely housed within the housing in which the piston slides, and the housing is molded as a single piece, making the device compact and strong. In fact, all components required to generate negative pressure (e.g., the piston and constant force mechanism) are completely inserted within the housing, which also serves as a protective cover.

[0025] Although structurally simple, the device according to the invention is able to achieve a constant negative pressure comparable to that achieved by devices using electric pumps, for example reaching values ​​between -50 mmHg and -150 mmHg.

[0026] The longitudinal housing can have several shapes. Preferably, the housing has a cylindrical shape with a circular cross section. Furthermore, the housing is hollow. This means that the housing has an internal central opening through which the piston slides and completely houses the constant force mechanism. The first end of the housing is directed toward the wound and is connected by a tube or catheter system to a special wound dressing placed in the patient's tissue. The dressing consists of a filler, usually a three-dimensional hollow reticular foam structure, and a sealing layer, ensuring an airtight closure and maintaining fluid communication between the wound and the device's housing.

[0027] The piston consists of a gasket, whose shape matches the cross-section of the housing to fit as closely as possible to the housing's inner wall, and a support fixed to the gasket associated with a constant force mechanism. Together with the housing's inner wall and first end, the gasket defines a pressure chamber within which negative pressure is generated. Movement of the piston changes the volume of the housing, i.e., the pressure chamber. Specifically, as the volume increases, air pressure decreases, resulting in suction from the wound area.

[0028] To generate a constant negative pressure, a load must be applied to the constant-force mechanism to activate the piston, causing it to slide within the housing. Thanks to a rear opening located at the second end of the housing, i.e., the rear end of the device away from the wound, the user (doctor, nurse, patient, etc.) inserts their finger into the opening and directly presses on the sliding piston for easy loading and activation. Pressing the piston expels air from the housing, i.e., the pressure chamber, through a valve system. The piston then automatically reverses flow due to the constant-force mechanism, expanding the volume within the pressure chamber within the housing. This creates suction on the wound, allowing wound fluid to flow from the wound into the housing.

[0029] As mentioned above, the housing is one-piece (cylindrical and hollow), and the constant force mechanism is completely located within the longitudinal housing. This significantly increases the compactness of the device. This compactness also facilitates handling of the device by the user, who can, in principle, treat wounds with one hand.

[0030] The rear opening can be any size that allows for the insertion of at least one adult finger. In one example, the rear opening can be sized to match the cross-section of the housing. In the case of a cylindrical housing, the rear opening can be circular and match the cross-section of the cylinder. Alternatively, the rear opening can be laterally disposed at the rear of the housing and have a generally oval cross-section. It will be appreciated that the rear opening is the only opening in the device through which one or more fingers can be inserted to manually slide the piston.

[0031] In one example, the housing may include a curved rear cover at the second end that partially covers the rear of the device, whereby the rear opening may be at least partially defined by the contour of the rear cover. Advantageously, the cover element may include a securing element for securing the constant force mechanism to the housing.

[0032] According to one example, the constant force mechanism may comprise at least one constant force spring secured to the piston in a layered manner. Preferably, the constant force mechanism comprises two constant force springs to ensure good axial traction by the longitudinal housing.

[0033] According to a preferred embodiment, the constant force mechanism includes a single constant force spring attached to the cylindrical support. The spring consists of a metal band that can be wrapped around the cylindrical support, one end of the band fixed to the cylindrical support, and the other end of the band provided with a connecting element that connects to the rear cover, particularly via a through-hole. Advantageously, when connected to the rear cover, the metal band rides on the curved contour of the rear cover. In other words, the curvature of the rear curve follows the stretched contour of the metal band that can be wrapped around the cylindrical support, so that the spring can generate all of its force on the same axis without torque. This allows the use of a single spring, since there is no rotational movement of the piston imprinted by the spring, which could cause excessive grinding friction and subsequent malfunction.

[0034] The piston includes a body having a first surface that defines a pressure chamber together with the first end of the housing. According to another example, the constant force mechanism can be at least partially enclosed within an interior region of the body of the piston. This prevents the constant force mechanism from preventing a user from inserting a finger through the rear opening to press on the piston. For example, a cylindrical support with one end of the constant force mechanism (spring) connected thereto can be inserted into such an interior region of the body of the piston.

[0035] In one example, the body of the piston may include a second surface that is used to manually load the constant force mechanism.

[0036] The valve system can be located in various positions, for example, at one of the ends of the housing, on the piston itself, or on a side of the housing. The valve system can be inserted into a wall area of ​​the housing, for example. Furthermore, the valve system can be fixed or movable, for example, integral with the piston.

[0037] According to one example of the present invention, the valve system may be disposed at a first end of the longitudinal housing.

[0038] Additionally, the valve system may include one or more one-way valves. In its simplest configuration, the valve system may include a single one-way valve that allows air to be expelled from the device when the piston is pushed toward the first end.

[0039] According to one example, the valve system may include two one-way valves. In particular, one valve is activated when the piston retracts and slides toward the second end of the housing. In this case, the pressure in the pressure chamber in the housing decreases, causing a flow from the outside (wound) of the housing to the inside. The other valve is activated when the piston is pushed forward (e.g., by the user's finger), i.e., toward the first end of the housing. In this case, the increase in pressure causes the air in the pressure chamber in the housing to be expelled to the outside. It can be seen that the valves in the valve system are mechanically activated without the use of electronic components.

[0040] According to one example, the valve system may comprise a cover element fixable to a first end of the longitudinal housing and a circular membrane arranged between the cover element and the first end of the longitudinal housing, i.e., the front of the housing itself. In particular, the cover element comprises a first opening for the inlet of wound fluid and a second opening for the outlet of air.

[0041] To ensure more effective fluid exchange between the interior and exterior of the housing, the front of the longitudinal housing at the first end may include an inlet hole at the first opening of the cover element and an outlet hole at the second opening of the cover element, and the circular membrane is configured to be interposed between the first and second openings of the cover element and the inlet and outlet holes of the housing.

[0042] According to one example, the circular membrane may be composed of a central disk element and a circumferential element concentric with and positioned outside the disk element. The circumferential element functions as a gasket and is fixed between the cover element and the longitudinal housing. This results in two one-way valves consisting of two half-disks (or flaps) of the circular membrane, i.e., the central disk element. Depending on the pressure generated in the pressure chamber in the housing, i.e., the movement of the piston, each half-disk can move in only one direction (up or down). The movement of the half-disks alternately opens and closes the two valves. That is, when one of the two valves is closed, the other is open, and vice versa. Specifically, the closure of the valves is due to the adhesion of the half-disk components of the circular membrane to the inlet or outlet holes at the first end of the housing.

[0043] To improve adhesion of the membrane to the surface of the first end and close the corresponding hole, the front of the longitudinal housing at the first end can have a pointed profile and include two surfaces defining a tip. These surfaces are configured to alternately contact the halves of the circular membrane as the piston slides within the longitudinal housing. The inlet hole of the housing is located on one of the two surfaces defining the tip, and the outlet hole is located on the other surface defining the tip.

[0044] To create a system with two alternating valves, the front of the housing may include an outer central edge and the cover element may include an inner central edge, whereby the central disk of the circular membrane disposed between the front of the housing and the cover element may be split into two half disks following squeezing of the central disk between the outer and inner central edges.

[0045] The device further comprises a graduated indicator preferably located along one side of the longitudinal housing to indicate the load state of the device as a function of piston position. [Brief explanation of the drawings]

[0046] These and other aspects of the invention will become more apparent on reading the following description of some of the embodiments described below.

[0047] [Figure 1A] 1A and 1B show schematic perspective front and rear views of an apparatus according to an example of the present invention. [Figure 1B] 1A and 1B show schematic perspective front and rear views of an apparatus according to an example of the present invention. [Figure 2A] 2 shows a schematic perspective view of the device of FIG. 1. [Figure 2B] 2 shows a schematic perspective view of the device of FIG. 1. [Figure 3A] 2 shows a schematic perspective view of the piston and cover element of the device of FIG. 1; [Figure 3B] 2 shows a schematic perspective view of the piston and cover element of the device of FIG. 1; [Figure 4A] 2 shows a schematic diagram of the constant force mechanism and circular membrane of the device of FIG. 1. [Figure 4B] 2 shows a schematic diagram of the constant force mechanism and circular membrane of the device of FIG. 1. [Figure 5] A schematic diagram of the device of FIG. 1 is shown together with an exploded view. [Figure 6A] 2A and 2B show schematic views of the back (a) and front (b) of the device of FIG. 1. [Figure 6B] 2A and 2B show schematic views of the back (a) and front (b) of the device of FIG. 1. [Figure 7A] 6a shows a schematic view of the device of FIG. 2 in longitudinal section along section line AA of FIG. 6a. [Figure 7B] 6a shows a schematic view of the device of FIG. 2 in longitudinal section along section line AA of FIG. 6a. [Figure 8A] 6a shows a schematic view of the device of FIG. 2 in longitudinal section along section line BB of FIG. 6a. [Figure 8B] 6a shows a schematic view of the device of FIG. 2 in longitudinal section along section line BB of FIG. 6a. [Figure 9A] 1(a) shows a schematic longitudinal section of the device and (b) details of the valve system. [Figure 9B] 1(a) shows a schematic longitudinal section of the device and (b) details of the valve system. [Figure 10] A schematic diagram of a circular membrane is shown. [Figure 11] 2 shows a schematic longitudinal cross-sectional view of the device of FIG. 1. [Figure 12A] 1 shows the front of the housing with and without the circular membrane. [Figure 12B] 1 shows the front of the housing with and without the circular membrane. [Figure 13A] 1 shows the rear of the cover element with and without the circular membrane. [Figure 13B] 1 shows the rear of the cover element with and without the circular membrane. [Figure 14A] 10A-10C show schematic perspective front and rear views of an apparatus according to another example of the present invention; [Figure 14B] 10A-10C show schematic perspective front and rear views of an apparatus according to another example of the present invention; [Figure 15A] 15 shows a schematic perspective view of the device of FIG. 14. [Figure 15B] 15 shows a schematic perspective view of the device of FIG. 14. [Figure 16A] 15 shows a schematic perspective view of the piston and cover elements of the device of FIG. 14. [Figure 16B] 15 shows a schematic perspective view of the piston and cover elements of the device of FIG. 14. [Figure 17A] 15 shows a schematic diagram of the constant force mechanism and circular membrane of the device of FIG. 14. [Figure 17B] 15 shows a schematic diagram of the constant force mechanism and circular membrane of the device of FIG. 14. [Figure 18] A schematic diagram of the device of FIG. 14 is shown together with an exploded view. [Figure 19] 15 shows a schematic view of the rear of the device of FIG. 14. [Figure 20A] 19 shows a schematic view of the device of FIG. 14 in longitudinal section along section line AA of FIG. 19. [Figure 20B] 19 shows a schematic view of the device of FIG. 14 in longitudinal section along section line AA of FIG. 19. [Figure 21A] 19 shows a schematic view of the device of FIG. 14 in longitudinal section along section line BB of FIG. 19. [Figure 21B]19 shows a schematic view of the device of FIG. 14 in longitudinal section along section line BB of FIG. 19. [Figure 22A] 14(a) shows a schematic longitudinal section of the device and (b) details of the valve system. [Figure 22B] 14(a) shows a schematic longitudinal section of the device and (b) details of the valve system. [Figure 23] A schematic diagram of a circular membrane is shown. [Figure 24A] 15 shows a schematic longitudinal cross section of the device of FIG. 14 with details of the first end. [Figure 24B] 15 shows a schematic longitudinal cross section of the device of FIG. 14 with details of the first end. [Figure 25A] 1 shows the front of the housing with and without the circular membrane. [Figure 25B] 1 shows the front of the housing with and without the circular membrane. [Figure 26A] 1 shows the rear of the cover element with and without the circular membrane. [Figure 26B] 1 shows the rear of the cover element with and without the circular membrane. [Figure 27A] 15 shows a schematic diagram of the device of FIG. 14. [Figure 27B] 15 shows a schematic diagram of the device of FIG. 14. DETAILED DESCRIPTION OF THE INVENTION

[0048] The main functions of the devices 1, 1' are explained in the following diagram:

[0049] The device 1, 1' comprises a longitudinal housing 10. The housing 10 is cylindrical with a first end 101 configured to connect to a wound and a second end 102. The piston 11 comprises a body and a first surface 22 that, together with the first end 101 of the housing, defines a pressure chamber 17. A constant force mechanism 12, 12' is connected to the piston 11 and a point on the second end 102 of the housing 10 and can be loaded to actuate the piston 11. In particular, the constant force mechanism 12, 12' is at least partially inserted into an interior region 23 of the body 21. It can be seen that a portion of the constant force mechanism 12, 12' is outside this interior region 23 and connects to a point on the housing at the second end 102. The body 21 comprises a second surface 24 that is utilized to manually load the constant force mechanism. In other words, the piston 11 can be pushed (e.g., using one or more fingers of an individual's hand) through the rear opening 14 of the housing 10 by directly acting on the second surface 24 to apply a load to the constant force mechanism 12, 12'. The body 21 of the piston 11 includes a first surface 22 that, together with the inner wall and the first end 101 of the housing 10, defines a pressure chamber 17 within which a negative pressure is generated. The device 1 further includes a valve system 13 that functions as an air vent when the piston 11 slides within the housing 10. The valve system 13 can be located in any region of the housing 10 (e.g., one end, the piston, or a side wall), as long as it ensures that air is expelled from the housing 10 when the piston slides toward the first end 101 and that fluid enters the housing 10 (i.e., into the pressure chamber 17) when the piston slides toward the second end 102. Details of the operation of the device are described with reference to the following examples.

[0050] 1a and 1b illustrate a negative pressure device 1 according to one embodiment of the present invention. The device 1 includes a longitudinal housing 10 having a first end 101 configured to be connected to a wound and a second end 102 opposite the first end 101. The second end 102 of the longitudinal housing 10 includes a rear opening 14 through which at least one finger of an individual's hand can be inserted to manually slide the piston 11 within the housing 10. The piston 11 (or its gasket 111), together with the inner wall of the housing 10 and the first end 101, defines a pressure chamber 17 within which negative pressure is generated. Movement of the piston 11 changes the volume within the housing 10, i.e., the pressure chamber 17. In particular, as the volume increases, air pressure decreases, resulting in suction from the wound area. FIG. 1a particularly illustrates a situation in which the piston 11 is at the second end 102 of the housing 10 and the volume of the pressure chamber 17 is at its maximum. In this case, the constant force mechanism 12 is not under load. Instead, Figure 1b shows the situation where the piston 11 is at the first end 101 of the housing 10 and the volume of the pressure chamber 17 is at a minimum. The sliding of the piston 11 towards the first end 101 of the housing is achieved by the thrust of the piston through the rear opening 14. This primes the constant force mechanism 12, which is fixed to the second end 102 of the housing 10 and simultaneously attached to the piston 11, and the device 1 is ready for the aspiration process.

[0051] 2a and 2b show perspective views of the apparatus of Fig. 1. The housing 10, and therefore the pressure chamber 17, is provided with two fixing points 103 at the second end 102 so that the constant force mechanism 12 can be fixed to the housing 10. Furthermore, the device 1 is provided with a valve system 13 at the first end 101. In particular, the valve system 13 comprises a cover element 131 having a first opening 133 connected to a special wound dressing placed in the patient's tissue by a tube or catheter system, and a second opening 134 for evacuating air from the pressure chamber 17.

[0052] 3a and 3b show perspective views of the piston 11 and the valve system 13. The piston 11 consists of a gasket 111 and a support 112. The constant force mechanism 12 is connected to the support 112 of the piston 11 by a first connector 113 (explained in more detail in the following figures) and to the housing 10 by a second connector 201 that interacts with a fixed point 103 of the housing 10. The valve system 13 consists of a cover element 131 and a circular membrane 132.

[0053] 4a and 4b show perspective views of the constant force mechanism 12 and the circular membrane 132. The constant force mechanism 12 according to one example includes two constant force springs 121, one above the other, attached to a cylindrical support 122. Specifically, each constant force spring 121 is made of a metal band wrapped around the cylindrical support 122, with one end of the band fixed to the cylindrical support 122 and the other end provided with a connecting element 123, e.g., a through hole, for connecting to the second connector 201 of the constant force mechanism 12. The two springs 121 are wrapped around the support 122 in two opposite winding directions. The circular membrane 132 includes a central disk element 135 and a circumferential element 136 concentric with and positioned outside the disk element 135. The circular membrane 132 will be described in more detail in the following figures.

[0054] FIG. 5 shows an exploded view of the device 1 according to the example of FIGS. 1-4. As mentioned above, the cover element 131 has a first opening 133 connected to the patient's wound by a tube or catheter system and a second opening 134 for evacuating air from inside the pressure chamber 17. Similarly, the housing 10 has an inlet hole 1011 that can be connected to the first opening 133 and an outlet hole 1012 that can be connected to the second opening 134. According to this embodiment, since the housing 10 has a cylindrical shape, the gasket 111 of the piston 11 has a circular shape with the same size as the cross-section of the housing 10 so as to fit perfectly against the inner wall of the housing 10. From the figure, it can be seen that the first connector 113 between the piston 11, i.e., the support 112, and the constant force mechanism 12, i.e., the spring 121, consists of two pins that pass through two holes in the support 112 and are fixed to the cylindrical support 122. Furthermore, it can be seen from the figure that the second connector 201 between the housing 10 at the second end 102 and the constant force mechanism 12, i.e. the spring 121, consists of two pins which pass through two holes 103 in the housing 10 and connect at one end to the connecting element 123 of the spring 121. A graduated indicator 16 extending longitudinally on the outside of the housing 10 marks the load state of the device.

[0055] Figure 6a shows the rear of device 1. Specifically, the figure illustrates the presence of a rear opening 14 through which one or more fingers of a hand can be inserted to activate constant force mechanism 12 and apply a load. Alternatively, Figure 6b illustrates the front of device 1, where first opening 133 and second opening 134 are present for connection to the wound and for venting air from pressure chamber 17.

[0056] Figures 7a and 7b show device 1 in longitudinal cross section along section AA in Figure 6a, and Figures 8a and 8b show device 1 in longitudinal cross section along section BB in Figure 6a. These figures show internal details of device 1, specifically pressure chamber 17 represented by the volume defined by piston 11 or gasket 111, the inner wall of housing 10, and first end 101 or top of housing 10. Additionally, the figures show the placement of springs 121 forming constant force mechanism 12 and their connection with piston 11 or support 112.

[0057] 9a and 9b show a longitudinal section of the device 1 and a detail of the valve system 13 arranged at the first end 101 of the housing 10. From FIG. 9b it can be seen that the housing 10 comprises an inlet hole 1011 and an outlet hole 1012 connected to the valve system 13. A circular membrane 132 is configured to fit over the surface of the cover element 131 and the top of the housing 10. In particular, the circular membrane comprises two half-disks 1351, 1352 that can be alternately moved to open and close the air or fluid passage determined by the first opening 133 and the second opening 134 on the cover element 131 and by the inlet hole 1011 and the outlet hole 1012 in the top of the housing 10.

[0058] FIG. 10 shows the circular membrane 132 in detail. The membrane 132 consists of a central disk element 135 and a circumferential element 136 arranged concentrically with and outside the disk element 135. The circumferential element 136 functions as a gasket and is fixed between the cover element 131 and the longitudinal housing 10, i.e., the upper part of the housing 10. The membrane 132 includes a central hole 137 for improving the alignment of the cover element 131 and the housing 10, and at least two side edges 139 connecting the central disk 135 to the circumferential element 136. The central disk 135 is divided into two half disks 1351, 1352, which may be called "semi-valves." The division of the central disc 135 into two is ensured by crushing said central disc 135 between the outer central edge 153 present on the top of the housing 10, i.e. on the pointed contour 15 defined by the inclined surface 151 and the inner central edge 138 present on the cover element 131.

[0059] 11 shows a schematic diagram of device 1, showing the presence of graduated indicator 16 arranged on a surface of housing 10, e.g., the outer surface, and a corresponding piston indicator 18 arranged on support 112 of piston 11. The position of the latter indicator 18 changes depending on the load state of device 1, i.e., depending on the position of piston 11 relative to first end 101 or second end 102 of housing 10. Advantageously, graduated indicator 16 defines the load state of device 10 with different colors.

[0060] FIG. 12a shows the front 104 of the housing 10 defined by a pointed contour 15 with two inclined surfaces 151 (consider, for example, the cross-sectional view of FIG. 8a). The inlet and outlet holes 1011, 1012 are located on these surfaces. The tip of the front 104 of the housing 10 is defined by a central edge 153 that is used to crush the circular membrane 132 and split it into two half-disks 1351, 1352. The front 104 of the housing 10 further comprises a central hole 105 for alignment with the membrane 132 by a corresponding hole 137.

[0061] Figure 12b shows the front part 104 of the housing 10 of Figure 12a on which rests the membrane 132. The circumferential element 136 of the membrane 132 functions as a gasket and the central disc 135 functions as an alternating valve as described above.

[0062] FIG. 13a shows the rear surface of the cover element 131, which has a first opening 133 and a second opening 134. In particular, the cover element includes an inner pin 1311 that serves to align the membrane 132 with the front part 104 of the housing 10 by inserting the pin 1311 into central holes 137 and 105 in the membrane 132 and the front part 104 of the housing 10, respectively. Furthermore, following the squeezing of the central disk 135 of the membrane 132 between the central inner edge 138 and the central outer edge 153 of the front part 104 of the housing 10, there is a central inner edge 138 that serves to define two half disks 1351 and 1352 of the circular membrane 132. To ensure a maximum seal, the outer portion of the diameter 1312 of the cover element 131 is joined to the circumferential element 136 of the circular membrane 132.

[0063] Figure 13b shows the rear side of the cover element 131 of Figure 13a, on which rests the membrane 132. The circumferential element 136 of the membrane 132 functions as a gasket, and the central disc 135 functions as an alternating valve as described above. An inner pin 1311 passes through a hole 137 in the membrane 132.

[0064] It will be seen that device 1 in Figures 1-13 shows valve system 13 located at first end 101. However, as noted above, valve system 13 may advantageously be located differently in other portions of device 1.

[0065] 14a and 14b show a negative pressure device 1' according to another embodiment of the present invention. This device differs essentially from the previous one only in that the constant force mechanism is composed of a single spring. Therefore, identical components between the two devices will not necessarily be described again. Therefore, the reference numbers of identical components will not be changed.

[0066] As with device 1 of FIGS. 1-13, device 1′ comprises a longitudinal housing 10 having a first end 101 configured to be connected to a wound and a second end 102 opposite first end 101. Second end 102 of longitudinal housing 10 comprises a rear opening 14 through which at least one finger of an individual's hand may be inserted to manually slide piston 11 within housing 10. Piston 11 (or its gasket 111), together with the interior wall of housing 10 and first end 101, define a pressure chamber 17 within which negative pressure is generated. Movement of piston 11 changes the volume within housing 10, i.e., pressure chamber 17. Notably, as the volume increases, air pressure decreases, resulting in suction from the wound area.

[0067] Figures 15a and 15b show perspective views of the device of Figure 14. The housing 10, i.e., the pressure chamber 17, comprises a curved rear cover 19 that partially covers the rear of the device 1' at the second end 102. This cover 19 has a fixing element 191 for the constant force mechanism 12'. Instead, a cover element 131' covers the first end 101 of the device 1'.

[0068] 16a and 16b show perspective views of the piston 11 and the cover element 131'. The piston 11 consists of a gasket 111, a support 112 and a component 114. From the figures it can be seen that the constant force mechanism 12' comprises a single spring 121 which can be fixed at its end to the rear cover 19 by corresponding fixing means 1211. In addition to the first and second openings 134, the cover element 131' comprises a central alignment hole 1313.

[0069] 17a and 17b show perspective views of the constant force mechanism 12' and the circular membrane 132. The constant force mechanism 12' in this example comprises a constant force spring 121 attached to a cylindrical support 122. Specifically, the constant force spring 121 is made of a metal band wrapped around the cylindrical support 122, one end of the band is fixed to the cylindrical support 122, and the other end is provided with a connecting element 123, for example a through hole, for connecting to the rear cover 19 by a fixing means 1211. The circular membrane 132 comprises a central disk element 135 and a circumferential element 136 arranged concentrically with and outside the disk element 135.

[0070] FIG. 18 shows an exploded view of the device 1 according to the embodiment of FIGS. 14-17. As mentioned above, the cover element 131′ includes a first opening 133, which is connected to the patient's wound by a tube or catheter system, and a second opening 134 for venting air from the interior of the pressure chamber 17. Similarly, the housing 10 includes an inlet hole 1011 that can be coupled to the first opening 133 and an outlet hole 1012 that can be coupled to the second opening 134. According to this embodiment, the housing 10 has a cylindrical shape, so the gasket 111 of the piston 11 has a circular shape with the same size as the cross-section of the housing 10 so as to fit perfectly against the inner wall of the housing 10. From the figure, it can be seen that the device 1′ includes a pin 113′ that extends from the support 112, passes through the cylindrical support 122, and is fixed to an additional component 114 that holds everything in place. This figure also shows the presence of a graduated indicator 16 located on the outside of the housing 10 to indicate the load state of the device 1′.

[0071] 19 shows the back of device 1'. Specifically, this view illustrates the presence of rear opening 14 through which one or more fingers of a hand may be inserted to activate constant force mechanism 12'. It can be seen that rear cover 19 partially covers opening 14.

[0072] 20a and 20b show device 1 in longitudinal cross section along section AA in Fig. 19, and Fig. 21a and 21b show device 1 in longitudinal cross section along section BB in Fig. 19. These figures show internal details of device 1', specifically pressure chamber 17 represented by the volume defined by piston 11, i.e., gasket 111, the inner wall of housing 10, and first end 101 of housing 10, i.e., the top of housing 10. Additionally, these figures show the placement of spring 121 forming constant force mechanism 12 and its connection with piston 11, i.e., support 112.

[0073] 22a and 22b show a longitudinal section of the device 1′ and a detail of the valve system 13 arranged at the first end 101 of the housing 10. From FIG. 22b, it can be seen that the housing 10 comprises an inlet hole 1011 and an outlet hole 1012 connected to the valve system 13. A circular membrane 132 is configured to fit over the surface of the cover element 131′ and the top of the housing 10. In particular, the circular membrane 132 comprises two half-disks 1351 and 1352 that can be alternately moved to open and close the air or fluid passage defined by the first and second openings 133 and 134 of the cover element 131′ and by the inlet hole 1011 and the outlet hole 1012 in the top of the housing 10. To hold the membrane 132, the cover element 131′ and the housing 10 in place, the top of the housing 10 comprises a pin 154 that passes through a central hole 137 of the membrane 132 and a central hole 1313 of the cover element 131′. It can also be seen from the figure that the contour of the outer surface of the cover element 131' is not flat but includes a raised area at the second opening 134 to facilitate the evacuation of air. This configuration of the cover element 131' can also be applied to the embodiment of Figures 1 to 13 described above. In particular, the circumferential element 136 is configured so that it can be crushed between the cover element 131' and the housing 10.

[0074] 23 shows the circular membrane 132 in detail. As in the previous example, the membrane 132 consists of a central disk element 135 and a circumferential element 136 arranged concentrically with and outside the disk element 135. The circumferential element 136 functions as a gasket and is fixed between the cover element 131 and the longitudinal housing 10, i.e., the upper part of the housing 10. The membrane 132 has a central hole 137 to improve its alignment in the cover element 131′ and the housing 10, and at least two side edges 139 connecting the central disk 135 to the circumferential element 136. The central disk 135 is divided into two half disks 1351, 1352, which may be called “semi-valves.” The division of the central disc 135 into two is ensured by crushing said central disc 135 between the upper part of the housing 10, i.e., the central edge 153 present on the pointed contour 15 defined by the inclined surface 151, and the inner central edge 138 present on the cover element 131.

[0075] Figures 24a and 24b show a schematic view of the device 1' with a detail of the front part 104 of the housing 10 cut in three-quarters. Figure 24b shows the positioning of the circular membrane 132 relative to the housing 10 and the cover element 131', determined by inserting a pin 154 into the central holes 137 and 1313 of the central membrane 132 and the cover element 131', respectively.

[0076] FIG. 25a shows the front 104 of the housing 10, which is defined by a pointed contour 15 with two inclined faces 151. The inlet holes 1011 and the outlet holes 1012 are present on these faces 151 (consider, for example, the cross section of FIG. 20a). The tip of the front 104 of the housing 10 is defined by a central edge 153 that is used to crush the circular membrane 132 and split it into two half-disks 1351, 1352. The front 104 of the housing 10 further comprises a central pin 154 for alignment with the membrane 132 by means of a corresponding hole 137.

[0077] Figure 25b shows the front portion 104 of the housing 10 of Figure 25a on which rests the membrane 132. In particular, the membrane 132 is on the outer portion 106 of the housing 10. The circumferential element 136 of the membrane 132 functions as a gasket, and the central disk 135 functions as an alternating valve as described above.

[0078] 26a shows the rear side of the cover element 131' with the first opening 133 and the second opening 134. In particular, the cover element comprises a central hole 1313 which serves to align the membrane 132 with the front part 104 of the housing 10 by inserting a pin 154 of the front part 104 of the housing 10. Furthermore, there is a central inner edge 138 which serves to define two half disks 1351, 1352 of the circular membrane 132, following the squeezing of the central disk 135 of the membrane 132 between said central inner edge 138 and the central edge 153 of the front part 104 of the housing 10. To ensure a maximum seal, the outer part of the diameter 1312 of the cover element 131' is joined to the circumferential element 136 of the circular membrane 132.

[0079] Figure 26b shows the rear side of the cover element 131' of Figure 14a on which the membrane 132 rests. The circumferential element 136 of the membrane 132 functions as a gasket and the central disc 135 functions as an alternating valve as described above. An inner pin 154 passes through a hole 137 in the membrane 132.

[0080] 27a and 27b show schematic diagrams of the device 1', illustrating the presence of graduated indicators 16 that can be disposed on a surface of the housing 10, e.g., the outer surface disposed on the support 112 of the piston 11, and corresponding piston indicators 18. It can be seen that these figures only show some components of the device 1'. For example, the housing 10 and the constant force mechanism 12' have been omitted from the figures. The position of indicators 18 changes depending on the load state of the device 1, i.e., depending on the position of the piston 11 relative to the first end 101 or the second end 102 of the housing 10. Advantageously, graduated indicators 16 define the load state of the device 10 with different colors.

[0081] Note that device 1' in Figures 14-27 shows valve system 13 located at first end 101. However, as discussed above, valve system 13 may be advantageously located differently in other portions of device 1.

[0082] Those skilled in the art may make some further modifications and variations to the above devices 1, 1' to meet further incidental needs, and all these modifications and variations fall within the scope of protection of the present invention as defined by the appended claims. [Explanation of symbols]

[0083] 1,1´ device (negative pressure device) 10. Housing 11 Piston 12, 12´ constant force mechanism 13 Valve System 14 Rear opening 15 Pointed Contours 16 graduated indicators 17 Pressure Chamber 21 Main Unit 22 First Surface 23 Inner area 24 Second Surface 101 first end 102 second end 103 Fixed point 104 Front 106 Outer part 111 Gasket 112 Support 113 First Connector 121 Constant force spring 122 Cylindrical support 123 Connecting Elements 131, 131´ Cover element 132 Circular membrane 133 First Opening 134 Second Opening 135 disk elements 136 Circumferential Elements 137 Central hole 138 inner center edge 139 Side Edge 151 Slope 153 outer center edge 154 center pin 201 Second Connector 1011 Entrance hole 1012 Exit hole 1313 Central hole 1351, 1352 half disc

Claims

1. a longitudinal housing (10) having a first end (101) configured to be connected to a wound and a second end (102) opposite said first end (101), the longitudinal housing (10) being of hollow, cylindrical, single-piece construction; a piston (11) that slides within the longitudinal housing (10) to generate negative pressure; a constant force mechanism (12, 12') configured to be loaded and operated by the piston (11), the constant force mechanism (12, 12') being fixed to the second end (102) of the longitudinal housing (10) and the sliding piston (11) and being disposed within the longitudinal housing (10); a valve system (13) for drawing air from the longitudinal housing (10) when the piston (11) slides towards a first end (101) of the longitudinal housing (10), and for introducing wound fluid into the longitudinal housing (10) when the piston (11) slides towards a second end (102) of the longitudinal housing (10); A negative pressure device (1, 1') for treating wounds and removing fluids from wounds, comprising: The constant force mechanism (12, 12') is entirely contained within the longitudinal housing (10) in which the piston (11) slides; The second end (102) of the longitudinal housing (10) has a rear opening (14) that allows one or more fingers of an individual's hand to be inserted to manually slide the piston (11) and apply a load to the constant force mechanism (12, 12').

2. 2. The device (1') according to claim 1, wherein the longitudinal housing (10) comprises a curved rear cover (19) at the second end (102) that partially covers the rear surface of the device (1').

3. 3. The device (1') according to claim 2, wherein the cover element (19) comprises a fixing element (191) for fixing the constant force mechanism (12') to the longitudinal housing (10).

4. 4. The device (1, 1') according to any one of claims 1 to 3, wherein the constant force mechanism (12, 12') comprises at least one constant force spring (121) fixed in a laminar fashion to the piston (11) that can be actuated by pressure exerted by one or more fingers of a user.

5. 5. The device (1') according to claim 2, 3 or 4, wherein the constant force mechanism (12') comprises a single constant force spring attached to a cylindrical support (122), the constant force spring being formed by a metal band that can be wound around the cylindrical support (122), one end of the band being fixed to the cylindrical support (122) and the other end of the band being provided with a connecting element (123), in particular a through hole, for connecting to the rear cover (19), the metal band following the curved contour of the rear cover (19) when connected to the rear cover (19).

6. 6. The device (1, 1') according to any one of claims 1 to 5, wherein the piston (11) comprises a body (21) having a first surface (22) that defines a pressure chamber (17) with a first end (101) of the longitudinal housing (10), and the constant force mechanism (12, 12') is at least partially confined to an interior region (23) of the body (21) of the piston (11).

7. 7. The device (1, 1') according to claim 6, wherein the body (21) of the piston (11) comprises a second surface (24) used to manually load the constant force mechanism (12, 12').

8. 7. The device (1, 1') according to any one of the preceding claims, wherein the valve system (13) is arranged at a first end (101) of the longitudinal housing (10).

9. 9. Device (1, 1') according to any one of claims 1 to 8, wherein the valve system (13) comprises two one-way valves.

10. 10. The device (1, 1') according to any one of claims 1 to 9, wherein the valve system (13) comprises a cover element (131, 131') fixable to the first end (101) of the longitudinal housing (10) and a circular membrane (132) arranged between the cover element (131, 131') and the first end (101) of the longitudinal housing (10).

11. 11. The device (1, 1') according to claim 10, wherein the cover element (131, 131') comprises a first opening (133) for the inlet of wound fluid and a second opening (134) for the outlet of air.

12. 12. The device (1, 1') according to claim 11, wherein the longitudinal housing (10) comprises a front portion (104) at the first end (101), the front portion (104) comprising an inlet hole (1011) at a first opening (133) of the cover element (131, 131') and an outlet hole (1012) at a second opening (134) of the cover element (131, 131').

13. 13. The device (1, 1') according to any one of claims 10 to 12, wherein the circular membrane (132) consists of a central disk element (135) and a circumferential element (136) arranged concentrically with and outside the central disk element (135), the circumferential element (136) acting as a gasket and fixed between the cover element (131) and the longitudinal housing (10).

14. 14. The device (1, 1') according to any one of claims 10 to 13, wherein the longitudinal housing (10) comprises a front portion (104) at the first end (101), the front portion (104) having a pointed contour (15) and comprising two surfaces (151) defining a tip, the two surfaces (151) being configured to come into alternating contact with the halves of the circular membrane (132) following sliding of the piston (11) inside the longitudinal housing (10).

15. 15. The device (1, 1') according to claim 13 or 14, wherein the front part (104) of the longitudinal housing has an outer central edge (153), the cover element (131, 131') has an inner central edge (138), and the central disk (135) of the circular membrane (132) is split into two half disks (1351, 1352) following squeezing of the central disk (135) between the outer central edge (153) and the inner central edge (138).

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