IL309420B2 - .automatic tourniquet and a method of controlling same - Google Patents

Description

XMTX-P-004-IL 1 AUTOMATIC TOURNIQUET AND A METHOD OF CONTROLLING SAME FIELD OF THE INVENTION[001] The present invention relates generally to medical devices and methods for compressing parts of the body in order to prevent bleeding.. More specifically, the present invention relates to tourniquets and automated control means and methods therefor.

BACKGROUND OF THE INVENTION[002] Tourniquets are medical devices that are used to apply pressure to a limb of a patient in order to limit, but not stop, the flow of blood. Tourniquets are useful in extreme medical conditions, such as, limb injuries and operations, but also for determining the location of a suitable vein for venipuncture. All known tourniquets are manually operated and adjusted, usually by a professional, such as, a medic, a paramedic, a nurse, or a physician. [003] Tourniquets in existing designs are configured to create circumferential tension, thereby forming a radial compression on the limb. The major issue with most tourniquets lies in that the friction between the tightening strip and the limb increases with the increase of the pressure on the limb, causing the underlying soft tissue to move along with the tightening strip. This effect results in the pinching of soft tissue and uneven distribution of pressure around the limb. The zones of high pressure on the limb may apply high stresses to the underlying soft tissues, causing additional pain and potentially leading to tissue damage. In the zones of low pressure, in turn, blood flow may not be sufficiently limited despite the overall high tension in the tourniquet. Furthermore, the non-uniform application of pressure necessitates unnecessarily high tightening in order to achieve the desired level of blood flow limiting, resulting in higher loads on the tightening means. Another problem caused by the presence of non-uniform application of pressure around the limb is that it makes it harder to consistently and predictably affect blood flow by tightening the tourniquet to a preset level, which may be a critical aspect especially for tourniquets with automatic tightening means. [004] The demand for using automated tourniquets has risen during recent years due to the following reasons. In some emergency occasions, for example, on a battlefield or a car accident, a critical time may pass, until professional assistance is provided to an injured patient. When a nonprofessional may try to apply a traditional non-automatic XMTX-P-004-IL 2 tourniquet, he/she may cause irreversible damage or not apply sufficient pressure to stop bleeding. For example, experiments conducted with a combat application tourniquet (CAT) yielded that the time for placement of the tourniquet on the limb varies between sec. for a non-trained user, 38 sec. for a trained user, and 58 for a trained user under pressure. Furthermore, the blood pulse elimination was at most 67% although the CAT is capable of better pulse elimination. [005] SUMMARY OF THE INVENTION[006] Accordingly, there is a need for a tourniquet which would provide an improvement of the respective technological field by providing uniform application of pressure around the limb and preventing pinching of a soft tissue when being tightened, decreasing the loads on tightening means and providing consistent and predictable correspondence between the level of tension provided by the tourniquet tightening means and the effect on the blood flow, thereby enabling reliable functioning of an automatic tightening means. There is further a need for a tourniquet that may be safely activated and single-handedly operated by a nonprofessional user and be configured to reliably provide a controlled amount of pressure to the user’s limb. [007] There is further a need for a method of controlling an automatic tourniquet that would provide an improvement of the respective technological field by providing consistent and predictable correspondence between the level of tension provided by the tourniquet tightening means and the effect on the blood flow, thereby increasing the reliability of the automatic tourniquet, and assuring safe single-handed operation thereof. [008] Some aspects of the invention may be directed to a tourniquet, comprising: a cuff band; a gear assembly attached to the cuff band, comprising a gear wheel having a through-conduit extending through the gear wheel; and at least one closed tightening strip threaded in the through-conduit, extending along the length of the cuff band and forming a loop therein, wherein the at least one tightening strip is selected from; a wire, a band, and a combination thereof; and wherein the gear assembly is configured to tighten the loop when driven in a first direction and to untighten the loop when driven in a second direction. [009] In some embodiments, the gear assembly further comprising gear wheel comprises a grooved rim; and wherein the through-conduit at least partially goes through XMTX-P-004-IL 3 a groove of the grooved rim. In some embodiments, the grooved rim comprises a circumferential groove for leading the tightening strip. In some embodiments, the gear wheel is a worm gear and the gear assembly further comprises a worm screw operatively engaged with the worm gear, and wherein the tourniquet further comprises an actuating means axially connected to the worm screw. [0010] In some embodiments, the cuff band comprises: a cuff strip; fastening means positioned at ends of the cuff strip; and at least one pair of rollers, each positioned at a respective end of the cuff strip. In some embodiments, the closed tightening strip is stretched between the at least one pair of rollers and threaded underneath the gear wheel when the automatic tourniquet is placed on a limb. [0011] In some embodiments, the actuating means are hand-driven means (e.g., comprising a handle for manually rotating the worm screw). In some additional or alternative embodiments, the actuating means comprise an electrical motor, and wherein the tourniquet further comprises a button for activating the electrical motor, and wherein the electrical motor is controlled to provide rotary torque to the gear assembly to cause the tourniquet to tighten to form a target pressure on a limb. [0012] In some embodiments, the gear assembly is designed to cause the tourniquet to tighten to form a target pressure on a limb. [0013] In some embodiments, the tourniquet further comprises one or more sensors configured to provide a signal indicative to tightening the tourniquet on a limb; and a controller in operative connection with said one or more sensors and the electric motor. [0014] In some embodiments, the controller is configured to control the electrical motor to provide a rotary torque to the gear assembly based on the signal of the one or more sensors. [0015] In some embodiments, the tourniquet further comprises a coupling connector in operative connection with the controller and configured for coupling high-frequency EM energy with high-voltage or medium-voltage cables and for receiving, from the actuating means, the signal representing a voltage or a current supplied by the electrical motor, and wherein the controller is configured to calculate electrical power consumed by the electrical motor, based on the signal representing a voltage or a current supplied by the electrical motor, and to control the electrical motor to provide the rotary torque to the gear assembly based on the calculated electrical power.

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[0016] In some embodiments, the controller is configured to control the electrical motor to provide rotary torque to the gear assembly, in a predetermined sequence. In some embodiments, the controller is further configured to operate the electrical motor to provide torque in a pulse-like manner, when the calculated electrical power reaches a predefined power consumption threshold. In some embodiments, the controller is further configured to: monitor at least one of (i) a current pressure applied on the limb; (ii) a tension of the tightening strip, and (iii) the electrical power consumed by the electrical motor to tighten the tightening strip; and control the electrical motor to provide the rotary torque to the gear assembly to retighten the tightening strip in order to form the target pressure on the limb, when the monitored current pressure, tension or the electrical power falls below a predefined pressure or tension threshold. id="p-17" id="p-17" id="p-17" id="p-17" id="p-17" id="p-17"

[0017] In some embodiments, the tourniquet further comprises a manual fast-release unit. In some embodiments, the gear assembly comprises locking mechanism preventing rotation of the gear assembly in the second direction. id="p-18" id="p-18" id="p-18" id="p-18" id="p-18" id="p-18"

[0018] Some additional aspects of the invention may be directed to a garment comprising the automatic tourniquet according to any one of the preceding claims. id="p-19" id="p-19" id="p-19" id="p-19" id="p-19" id="p-19"

[0019] Some aspects of the invention may be directed to a method of controlling an automatic tourniquet, by at least one controller, the method comprising: receiving a signal to operate the automatic tourniquet to tighten a strip of the automatic tourniquet on a limb, operating an electric motor of the automatic tourniquet to drive a gear assembly, said gear assembly being operatively connected to the tightening strip and configured to tighten the tightening strip when driven; monitoring electrical power consumed by the electric motor; and halting the electric motor when an amount of the consumed electrical power reaches a predefined threshold. id="p-20" id="p-20" id="p-20" id="p-20" id="p-20" id="p-20"

[0020] In some embodiments, the method further comprises determining, based on the monitored electrical power, the type of the limb; and setting the predefined threshold, based on the determined type of the limb. id="p-21" id="p-21" id="p-21" id="p-21" id="p-21" id="p-21"

[0021] In some embodiments, the method further comprises, calculating an ongoing power consumption profile, based on monitored electrical power; calculating a similarity metric value, representing a degree of similarity between the ongoing power consumption profile and at least one predefined power consumption profile associated with a specific XMTX-P-004-IL type or size of limbs or location thereon; determining the specific type of size of the limb or location thereon, based on the calculated similarity metric value; and setting the predefined threshold, based on the determined type of the limb. id="p-22" id="p-22" id="p-22" id="p-22" id="p-22" id="p-22"

[0022] In some embodiments, the predefined threshold was determined experimentally. id="p-23" id="p-23" id="p-23" id="p-23" id="p-23" id="p-23"

[0023] In some embodiments, the method further comprises generating the typical power consumption profile for specific location at a specific limb. id="p-24" id="p-24" id="p-24" id="p-24" id="p-24" id="p-24"

[0024] In some embodiments, the method further comprises, analyzing, after a predetermined amount of time, the monitored of at least one of, the voltage and the current to determine a type of limb; and selecting a power provision profile based on the analysis, wherein the power provision profile comprises a power provision duration required to tighten the tightening strip around the determined type of limb to a desired level of tension. id="p-25" id="p-25" id="p-25" id="p-25" id="p-25" id="p-25"

[0025] In some embodiments, the method further comprises receiving from at least one sensor included in the automatic tourniquet a signal indicative of a pressure applied on the limb; and controlling the operation of the electric motor further based on the received signal. id="p-26" id="p-26" id="p-26" id="p-26" id="p-26" id="p-26"

[0026] In some embodiments, the gear assembly comprises a gear having a grooved rim with a through-conduit extending through the grooved rim in the radial direction thereof, and wherein the strip is threaded in the through-conduit. In some embodiments, the method further comprises operating the electrical motor to provide torque in a pulse-like manner, when the amount of the consumed electrical power reaches the predefined threshold. id="p-27" id="p-27" id="p-27" id="p-27" id="p-27" id="p-27"

[0027] In some embodiments, the method comprises: monitoring a tension of the tightening strip, and controlling the electrical motor to provide the rotary torque to the gear assembly to retighten the tightening strip in order to form the target pressure on the limb, when the monitored current pressure or tension falls below a predefined pressure or tension threshold.

BRIEF DESCRIPTION OF THE DRAWINGS[0028] The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, XMTX-P-004-IL 6 both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings in which: [0029] Fig. 1A is an illustration of a tourniquet applied on a limb according to some embodiments of the invention; [0030] Fig. 1B is an illustration of a top view of a tourniquet according to some embodiments of the invention; [0031] Fig. 1C is an image of a gear assembly and a motor to be included in a tourniquet according to some embodiments of the invention; [0032] Fig. 2 is a block diagram of a tourniquet according to some embodiments of the invention; [0033] Fig. 3 is a flowchart of a method of controlling an automatic tourniquet according to some embodiments of the invention; and [0034] Fig. 4 includes graphs of the power consumption of the tourniquet when placed on two types of limbs according to some embodiments of the invention. [0035] It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.

DETAILED DESCRIPTION OF THE PRESENT INVENTION[0036] One skilled in the art will realize the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing embodiments are therefore to be considered in all respects illustrative rather than limiting of the invention described herein. Scope of the invention is thus indicated by the appended claims, rather than by the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. [0037] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, and XMTX-P-004-IL 7 components have not been described in detail so as not to obscure the present invention. Some features or elements described with respect to one embodiment may be combined with features or elements described with respect to other embodiments. For the sake of clarity, discussion of the same or similar features or elements may not be repeated. [0038] [0039] According to the concept of the present invention, the issue of providing uniform application of pressure around the limb, and further issues of preventing pinching of a soft tissue when being tightened, decreasing the loads on tightening means and providing consistent and predictable correspondence between the level of tension provided by the tourniquet tightening means and the effect on the blood flow, are further mitigated by the following aspects of configuration of the tourniquet tightening means. [0040] In the suggested configuration, by having the closed tightening strip which extends through the length of the cuff band, forms the loop therein and is engaged with the gear wheel via the through-conduit extending therethrough, the tightening strip is configured to be pulled from both sides simultaneously and evenly, when being tightened. Thereby, a uniformly increasing application of pressure around the limb may be achieved. Furthermore, in the suggested solution, the tightening strip and, accordingly, the loop forms thereby are arranged freely in the cuff band, when untightened, as the tightening strip is not fixed either to the gear wheel or the cuff band. This aspect also contributes to the even distribution of force along the tightening strip during tightening. [0041] The suggested configuration further enables the realization of the claimed method. In particular, by having the tourniquet of the suggested configuration, the decision of halting the electric motor that actuates the tightening means of the tourniquet can now be made based on the consumed electrical power, since this parameter becomes reliably indicative of the pressure applied around the limb, and, hence, of the effect on the blood flow. [0042] Therefore, in some aspects of the present invention, it provides for an automatic tourniquet and method of controlling thereof that allows a simple and safe way to form a required pressure on a limb, for example, during injury. Such a tourniquet may be operated single-handedly by the injured user regardless of his knowledge in providing emergency care.

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[0043] Reference is now made to Fig. 1A which is an illustration of an automatic tourniquet applied on a limb according to some embodiments of the invention. A tourniquet 100 may be applied on a limb 5 (e.g., leg, arm, etc.) of a patient/user. Tourniquet 100 may include a cuff band 10, and a gear assembly 20 attached to cuff band 10. Tourniquet 100 may be activated by pressing on activation button 55, as discussed herein below with respect to Fig. 2. [0044] Reference is now made to Figs. 1B and 1C which are an illustration of a tourniquet and an image of a gear assembly, respectively, according to some embodiments of the invention. [0045] Cuff band 10 may be any suitable band, for example, a band used in commercial tourniquets (e.g., CAT) having a width of approximately 25 mm. [0046] In some embodiments, gear assembly 20 may include a gear wheel 22 having a through-conduit 21 extending through gear wheel 22. In the nonlimiting example illustrated in Fig. 1B and shown in Fig. 1C, through-conduit 21 comprises two exit/entry holes 23a and 23b and a circumferential groove 25. Therefore, gear assembly 20 may further include a grooved rim 26 attached to gear wheel 22. As shown grooved rim comprises exit/entry holes 23a and 23b and circumferential groove 25. *** [0047] [0048] In some embodiments, gear wheel 22 is worm gear and a gear assembly 20 may further include a worm screw 28 operatively engaged with worm gear 22. In some embodiments, worm screw 28 is axially connected and actuated by actuating means 40. [0049] In some embodiments, actuating means 40 may include an electric motor, as discussed in detail with respect to Fig. 3. [0050] In some embodiments, tourniquet 100 may further include at least one closed tightening strip 30 threaded in through-conduit 21, extending along the length of cuff band 10 and forming a loop therein, wherein at least one tightening strip 30 is selected from; a wire, a band, and a combination thereof. For example, closed tightening strip may be positioned so as to be engaged with grooved rim 26 during tightening, but be disengaged when untightened. E.g., closed tightening strip 30 may enter rim 26 via hole 23a and lead by circumferential groove 25 to be exit from hole 23b. In some embodiments, strip 30 is freely threaded in through-conduit 21 and may slide along XMTX-P-004-IL 9 through-conduit 21, in an untightened state. In some embodiments, any anchoring of strip to gear assembly 20 is avoided. [0051] In some embodiments, cuff band 10 may further include a cuff strip 11 and at least one pair of rollers 15 and 16, each positioned at a respective end of cuff strip 10. In some embodiments, closed tightening strip 30 is stretched between the at least one pair of rollers 15 and 16 and threaded underneath gear 22, for example, when automatic tourniquet 100 is placed on a limb 5. [0052] In some embodiments, cuff band 10 may further include fastening means and 13 positioned at the ends of cuff strip 11. Fastening means 12 and 13 may be any fastening means known in the art, such as but not limited to, hooks and loops fastening means, a clip, a buckle, and the like. For example, a magnetic buckle may be used. In such case tourniquet 100 may be in an open state and a magnetic buckle may allow a user to buckle tourniquet 100 using a single hand, by simply positioning the male 12 and female 13 buckle components adjacent to each other, and the magnetic force aligns and seals the buckle. Thereby, further improvement of the respective technological field may be achieved by additionally facilitating the single-handed usage of the tourniquet. [0053] In some embodiments, gear assembly 20 is configured to tighten the loop formed by closed tightening strip 30 when driven in a first direction and to untighten the loop when driven in a second direction. Accordingly, the threading of tightening strip in rim 26, causes tightening strip 30 to wrap around rim 26 (e.g., in groove 25) thus shortening the length of the loop, and thereby tightening cuff 10. [0054] In some embodiments, gear assembly 20 is designed to cause tourniquet 100 to tighten to form a target pressure on limb 5, for example, between of 250 to 350 mm Hg. [0055] In some embodiments, gear assembly 20 may comprise a locking mechanism (not illustrated) preventing rotation of the gear assembly in the second direction. [0056] In some embodiments, tourniquet 100 may further include a manual fast-release unit (not illustrated). In case of a false positive situation when tourniquet 100 is activated when it is not needed, the user may have the option to immediately release the tourniquet pressure. For example, the user may cut tightening strip 30. In another example, the user may pull a strap connected to a cutting knife pre-installed in the system or may pull a pin disassembling gear assembly 20.

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[0057] Reference is now made to Fig. 2, which is a block diagram of tourniquet 1according to some embodiments of the invention. In some embodiments, in addition to cuff band 10, gear assembly 20, closed tightening strip 30 and actuation means 40, tourniquet 100 may further include a controller 50. [0058] In some embodiments, actuation means 40 may include a DC motor 41 and a DC motor drive 42 in communication with controller 50. In some embodiments, controller 50 may be configured to control DC motor 41 to rotate warm screw 28 in a first direction in order to tighten cuff band 10 and in the second opposite direction in order to untighten cuff band 10. [0059] In some embodiments, controller 50 may be any microcontroller (e.g., a chip) known in the art and may further be powered by a battery 60. Battery 60 (e.g., a lithium battery) may also provide power to DC motor 41 and DC motor driver 42. [0060] In some embodiments, tourniquet 100 may further include an activation button (illustrated also in Fig. 1) for activating actuating means 40 to rotate worm screw to wrap strip 30 around rim 26 in order to tighten cuff band 10 around limb 5. [0061] In some embodiments, tourniquet 100 may further include a battery charger and a safety switch 64 for preventing accidental activation of the device. Therefore, only after the removal of safety switch 64, the activation of tourniquet 100 may be done by pressing activation button 55. In some embodiments, battery charger 62 may be coupled to a power adapter therefore, allowing battery 60 to be recharged from a variety of electricity sources including directly from a socket of the electric grid. [0062] In some embodiments, controller 50 may be in communication with an auxiliary switch 52 for providing an indication for the tightening (e.g., pressure increase) or untightening (e.g., pressure decrease) in tourniquet 100. In some embodiments, tourniquet 100 may further include light-emitting diodes (LEDs) 54. LEDs 54 may provide various visual information. For example, controller 50 may use LEDs 54 to show the amount of time tourniquet 100 is being tightened on the limb. For example, controller may include an internal clock and may be configured to identify the time at which the pressure (e.g., electrical power indicative of the pressure) reaches the predefined threshold and present a marker indicative of one of the total time from reaching the predefined threshold till present, the time in minutes from which reaching the predefined threshold and the like.

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[0063] In some embodiments, the tourniquet further comprises a coupling connector in operative connection with controller 50 and configured for coupling high-frequency EM energy with high-voltage or medium-voltage cables and for receiving, from the actuating means 40, the signal representing a voltage or a current supplied by the electrical motor, and wherein controller 50 is configured to calculate electrical power consumed by electrical motor 41, based on the signal representing a voltage or a current supplied by the electrical motor, and to control the electrical motor to provide the rotary torque to the gear assembly 20 based on the calculated electrical power. [0064] Additional examples may include, the state of the battery, power on/off, and the like. In some embodiments, other visual means may be used, such as but not limited to, screen, a touchscreen, and the like. [0065] In some embodiments, tourniquet 100 may further include one or more sensors in operative connection with controller 50. One or more sensors 70 may be selected from: a pressure sensor, an attachment sensor, a thermometer, an accelerometer, a force sensor, and the like. A nonlimiting example for a pressure sensor 70 may include a flexible sensor, such as, a piezoelectric sensor, a flexible force-sensitive resistor and the like. Such a flexible sensor may easily fit or adjust to the shape of the limb, thus may be assembled on the cuff band 10. [0066] In some embodiments, one or more sensors 70 are configured to provide a signal indicative of tightening the tourniquet on a limb (e.g., pressure, tension, etc.) and controller 50 may be configured to control electrical motor 41 to provide a rotary torque to gear assembly 20 based on the signal. [0067] Additionally or alternatively, in some embodiments, controller 50 may be configured to receive from DC motor driver 24 of actuating means 40 a signal representing a voltage or a current supplied by electrical motor 41 to gear assembly 20, and wherein controller 20 is configured to calculate electrical power consumed by electrical motor 41, based on the signal. Thereby, controller 50 may to control electrical motor 41 to provide the rotary torque to gear assembly 20 based on the calculated electrical power, as discussed in detail with respect to the method of Fig. 3. [0068] It shall be appreciated that, due to the benefits of the suggested configuration of the tightening means (e.g., the fact that tightening strip 30 is freely engaged with gear wheel 22), in some embodiments, it may be sufficient to control provision of the rotary XMTX-P-004-IL 12 torque based on the calculated electrical power only, thereby omitting the usage of additional sensors (e.g., pressure or tension sensors), and thus simplifying the configuration of the tourniquet. Hence, additional improvement to the respective technological field may be further achieved. [0069] In some embodiments, controller 50 is configured to control electrical motor to provide rotary torque to the gear assembly, in a predetermined sequence. For example, motor 41 may be configured to apply the pressure in small steps (e.g., each step corresponds to one rotation of the motor’s axis) while applying 5 steps forward in the tightening direction and 2 steps backward in the untightening direction until reaching the target pressure. This form of operation may allow trapped body organs and soft skin tissue to be released, thereby further contributing to the abovementioned technical improvement by preventing pinching of a soft tissue when tightening the tourniquet. [0070] In some embodiments, controller 50 is further configured to operate electrical motor 41 to provide torque in a pulse-like manner, when the calculated electrical power reaches a predefined power consumption threshold. [0071] In some embodiments, in the case that a larger amount of force may be necessary to accommodate a large limb (e.g., the upper leg), battery 60 power may not suffice. To mitigate this, tourniquet 100 may be operated in on and off pulses sequence, providing periods of rest to preserve battery life. For example, when a high current is drawn to achieve high levels of motor torque, the battery voltage may drop down and the power levels may be restricted. Therefore, by giving the battery time to recover (motor stop), the voltage goes up again and the battery is ready for high power pulse. Thereby, further contribution to the improvement of the technological field may be achieved by improving the power consumption regime and, consequently, increasing battery life of the automatic tourniquet. [0072] Reference is now made to Fig. 3 which is a flowchart of a method of controlling an automatic tourniquet, by at least one controller according to some embodiments of the invention. The method of Fig. 3 may be performed by controller 50 or by any other suitable controller. The method may be applied following the buckling of tourniquet 1around limb 5. [0073] In step 310, the method may include receiving a signal to operate the automatic tourniquet to tighten a strip of the automatic tourniquet on a limb. In some embodiments, XMTX-P-004-IL 13 the user may press activation button 55, therefore controller 50 may receive the signal to operate the automatic tourniquet. [0074] In step 320, the method may include operating an electric motor of the automatic tourniquet to drive a gear assembly, the gear assembly being operatively connected to the strip and configured to tighten the strip when driven. For example, electric motor 41 may be operated to rotate worm screw 28, thereby causing gear wheel and groove rim 26 to rotate in a first direction, thus causing strip 30 to wrap around rim 26 (inside groove 25). The wrapping of strip 30, may shorten the length of a loop made by strip, thereby tightening cuff band 10 over limb 5. In some embodiments, during the rotating and wrapping act, strip 30 may slide and roll over rollers 15 and 16, thereby ensuring a uniform tension along strip 30. In some embodiments, forming a uniform tension along strip 30 may ensure forming a uniform pressure on limb 5. [0075] In step 330, the method may include monitoring an electrical power consumed by the electric motor. For example, controller 50 may receive from motor driver 42 a signal representing at least the voltage and/or the current consumed by motor 41 and determining the power consumption based on the signal. [0076] In some embodiments, the method may include calculating an ongoing power consumption profile, based on monitored electrical power. In some embodiments, the power consumption profile may include a plurality of voltage, current and/or consumed power values associated with a timestamp with respect to the start of the tightening cycle. [0077] In step 340, the method may include halting the electric motor when an amount of the consumed electrical power reaches a predefined threshold. [0078] In some embodiments, the predefined threshold was determined experimentally. In nonlimiting experiments conducted using tourniquet 100 on legs and hands of 3 male volunteers ages 25, 38, and 49, the amount of power required to achieve desired blood flow occlusion was measured and an ongoing power consumption profiles were calculated, which were further taken as typical. The blood occlusion was validated using Doppler ultrasound and pulse oximeter. In some embodiments, a typical power consumption profiles for hands and legs, which consisted of an average time series. A nonlimiting example of such profiles for a leg and a hand is given in the graphs of Fig. 4. The graphs show the difference in power consumption an indication of a pressure built between the two types of limbs of the same person.

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[0079] In some embodiments, the method may include analyzing, after a predetermined amount of time, the monitored of at least one of, the voltage and the current to determine a type of limb; and selecting a power provision profile based on the analysis, wherein the power provision profile may include a power provision duration required to tighten the tightening strip around the determined type of limb to a desired level of tension. In the nonlimiting example of Fig. 4, in order to form sufficient pressure on the leg (which is a much larger limb) using the tourniquet used for the hand, a sequence of tightening pulses may be provided by the motor. Therefore, the method may further comprises operating electrical motor 41 to provide torque in a pulse-like manner, when the amount of the consumed electrical power reaches the predefined threshold. [0080] In some embodiments, the method may include calculating a similarity metric value (e.g., using root mean square (RMS) similarity method, or any similar method known in the art), representing a degree of similarity between the ongoing power consumption profile and at least one predefined power consumption profile associated with a specific type or size of limbs or location thereon, defined for example, experimentally as discussed above. In some embodiments, determining the specific type of size of the limb or location thereon, is may done based on the calculated similarity metric value; and setting the predefined threshold (e.g., tension, pressure or electrical power consumption threshold), based on the determined type of the limb. For example, controller 50 may store thereon a lookup table associating different types of limbs at various sizes (e.g., circumference) with a corresponding power consumption profile and power consumption threshold. [0081] In some embodiments, the method may further include generating typical power profile for a specific location at a specific limb, for example, upper or lower leg, upper or lower arm and the like. [0082] In some embodiments, the method may include receiving from at least one sensor included in the automatic tourniquet a signal indicative of a pressure applied on the limb; and controlling the operation of the electric motor further based on the received sign. For example, sensor 70 may provide the pressure profile and the halting of motor may be determined based on a signal indicative of the blood pressure in the limb received from sensor 70.

XMTX-P-004-IL id="p-83" id="p-83" id="p-83" id="p-83" id="p-83" id="p-83"

[0083] In some embodiments, sensor 70 may be a tension sensor configured to measure the tension in strip 30. In some embodiments, controller 50 may monitor at least one of (i) a current pressure applied on the limb; (ii) a tension of the strip, by receiving signals from sensor 70; and (iii) the electrical power consumed by the electrical motor to tighten the tightening strip (e.g., by applying electrical power in predefined time intervals), and controlling the electrical motor to provide the rotary torque to the gear assembly to retighten the strip in order to form the target pressure on the limb, when the monitored current pressure, tension or electrical power falls below a predefined pressure, tension or power consumption threshold. It should be understood that, in some embodiments, the tension or pressure threshold may be calculated from the power consumption profile, therefore, monitoring the tension by sensor 70 may be redundant, as discussed above. [0084] The need to retighten the tourniquet is a critical aspect of first aid effectiveness. The injured limb tends to slightly reduce its size after about 10 minutes since tourniquet placement. In many cases the patient may be covered and continued bleeding may be undetected, thereby increasing the risk of a blood loss, especially in cold weather. Furthermore, the tourniquet may loosen due to limb movement. Hence, by providing function of automatic monitoring of the tenson of the tightening strip (or other relevant parameters, as described above) and automatic retightening when the current tension is insufficient, the present invention further provides an improvement to the respective technological field. [0085] As can be seen from the provided description, the present invention represents a tourniquet that provides an improvement of the respective technological field by providing uniform application of pressure around the limb and preventing pinching of a soft tissue when being tightened, decreasing the loads on tightening means and providing consistent and predictable correspondence between the level of tension provided by the tourniquet tightening means and the effect on the blood flow, thereby enabling reliable functioning of an automatic tightening means. The suggested tourniquet may be safely activated and single-handedly operated by a nonprofessional user, and is configured to reliably provide a controlled amount of pressure to the user’s limb. [0086] The present invention further represents a method of controlling an automatic tourniquet that provides an improvement of the respective technological field by XMTX-P-004-IL 16 providing consistent and predictable correspondence between the level of tension provided by the tourniquet tightening means and the effect on the blood flow, thereby increasing the reliability of the automatic tourniquet, and assuring safe single-handed operation thereof. [0087] Unless explicitly stated, the method embodiments described herein are not constrained to a particular order or sequence. Furthermore, all formulas described herein are intended as examples only and other or different formulas may be used. Additionally, some of the described method embodiments or elements thereof may occur or be performed at the same point in time. [0088] While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents may occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention. [0089] Various embodiments have been presented. Each of these embodiments may of course include features from other embodiments presented, and embodiments not specifically described may include various features described herein.

Claims (27)

1. A tourniquet, comprising: a cuff band; a gear assembly attached to the cuff band, comprising a gear wheel having a through-conduit extending through the gear wheel; at least one closed tightening strip threaded in the through-conduit, extending along the length of the cuff band and forming a loop therein; and at least one pair of rollers, each roller of the at least one pair is positioned at a respective end of the cuff band; wherein the closed tightening strip is stretched between the at least one pair of rollers and threaded underneath the gear wheel when the automatic tourniquet is placed on a limb; and wherein the at least one tightening strip is selected from; a wire, a band, and a combination thereof; and wherein the gear assembly is configured to tighten the loop when driven in a first direction and to untighten the loop when driven in a second direction.

2. The tourniquet of claim 1, wherein the gear wheel comprises a grooved rim; and wherein the through-conduit at least partially goes through a groove of the grooved rim.

3. The tourniquet of claim 2, wherein the grooved rim comprises a circumferential groove for leading the tightening strip.

4. The tourniquet according to any one of claims 1-3, wherein the gear wheel is a worm gear and the gear assembly further comprises a worm screw operatively engaged with the worm gear, and wherein the tourniquet further comprises an actuating means axially connected to the worm screw.

5. The tourniquet according to any one of claims 1-4, wherein the cuff band comprises: a cuff strip; and fastening means positioned at ends of the cuff strip.

6. The tourniquet according to any one of claims 1-5, wherein the actuating means are hand-driven means.

7. The tourniquet according to any one of claims 1-6, wherein the actuating means comprise an electrical motor, and wherein the tourniquet further comprises a button for activating the electrical motor, and wherein the electrical motor is controlled to provide rotary torque to the gear assembly to cause the tourniquet tighten to form a target pressure on a limb.

8. The tourniquet according to any one of claims 1-7, wherein the gear assembly is designed to cause the tourniquet tighten to form a target pressure on a limb.

9. The tourniquet according to any one of claims 1-8, further comprising one or more sensors configured to provide a signal indicative to tightening the tourniquet on a limb; and a controller in operative connection with said one or more sensors and the electric motor.

10. The tourniquet of claim 9, wherein the controller is configured to control the electrical motor to provide a rotary torque to the gear assembly based on the signal.

11. The tourniquet according to any one of claims 4-8, further comprising a coupling connector for coupling high-frequency EM energy with high-voltage or medium-voltage cables figured to receive from the actuating means the signal representing a voltage or a current supplied by the electrical motor, and wherein the controller is configured to calculate electrical power consumed by the electrical motor, based on the signal of the one or more sensors, and to control the electrical motor to provide the rotary torque to the gear assembly based on the calculated electrical power.

12. The tourniquet according to any one of claims 9-11, wherein the controller is configured to control the electrical motor to provide rotary torque to the gear assembly, in a predetermined sequence.

13. The tourniquet according to any one of claims 9-12, wherein the controller is further configured to operate the electrical motor to provide torque in a pulse-like manner, when the calculated electrical power reaches a predefined power consumption threshold.

14. The tourniquet according to any one of claims 9-13, wherein the controller is further configured to: monitor at least one of current pressure applied on the limb or a tension of the tightening strip, and control the electrical motor to provide the rotary torque to the gear assembly to retighten the tightening strip in order to form the target pressure on the limb, when the monitored current pressure or tension falls below a predefined pressure or tension threshold.

15. The tourniquet according to any one of claims 1-12, further comprising a manual fast-release unit.

16. The tourniquet according to any one of claims 1-13, wherein the gear assembly comprises locking mechanism preventing rotation of the gear assembly in the second direction.

17. A garment comprising the automatic tourniquet according to any one of the preceding claims.

18. A method of controlling an automatic tourniquet, by at least one controller, the method comprising: receiving a signal to operate the automatic tourniquet to tighten a closed tightening strip of the automatic tourniquet on a limb, operating an electric motor of the automatic tourniquet to drive a gear assembly, said gear assembly being operatively connected to the closed tightening strip and configured to tighten the closed tightening strip when driven, wherein tightening the tightening strip comprises rolling the closed tightening strip around at least one pair of rollers, each roller of the at least one pair is positioned at a respective end of a cuff band of the automatic tourniquet; monitoring electrical power consumed by the electric motor; and halting the electric motor when an amount of the consumed electrical power reaches a predefined threshold.

19. The method of claim 18, further comprising determining, based on the monitored electrical power, the type of the limb; and setting the predefined threshold, based on the determined type of the limb.

20. The method of claim 18, further comprising: calculating an ongoing power consumption profile, based on monitored electrical power; calculating a similarity metric value, representing a degree of similarity between the ongoing power consumption profile and at least one predefined power consumption profile associated with a specific type or size of limbs or location thereon; determining the specific type of size of the limb or location thereon, based on the calculated similarity metric value; and setting the predefined threshold, based on the determined type of the limb.

21. The method of any one of claims 18 to 20, wherein the predefined threshold was determined experimentally.

22. The method according to any one of claims 18 to 21, further comprising: generating the typical power consumption profile for specific location at a specific limb.

23. The method according to any one of claims 18 to 22, further comprising: analyzing, after a predetermined amount of time, the monitored of at least one of, the voltage and the current to determine a type of limb; and selecting a power provision profile based on the analysis, wherein the power provision profile comprises a power provision duration required to tighten the tightening strip around the determined type of limb to a desired level of tension.

24. The method according to any one of claims 18 to 23, further comprising: receiving from at least one sensor included in the automatic tourniquet a signal indicative of a pressure applied on the limb; and controlling the operation of the electric motor further based on the received signal.

25. The method according to any one of claims 18 to 24, wherein the gear assembly comprises a gear having a grooved rim with a through-conduit extending through the grooved rim in the radial direction thereof, and wherein the tightening strip is threaded in the through-conduit.

26. The method according to any one of claims 18-25, wherein the method further comprises operating the electrical motor to provide torque in a pulse-like manner, when the amount of the consumed electrical power reaches the predefined threshold.

27. The method according to any one of claims 18-26, wherein the method further comprises: monitoring at least one of (i) a current pressure applied on the limb; (ii) a tension of the tightening strip, and (iii) an electrical power consumed by the electrical motor to tighten the tightening strip, and controlling the electrical motor to provide the rotary torque to the gear assembly to retighten the tightening strip in order to form the target pressure on the limb, when the monitored current pressure, tension or electrical power falls below a predefined pressure, tension or electrical power threshold, respectively.