Automatic tourniquet and a method of controlling same

Abstract

A tourniquet is disclosed. The tourniquet may include: 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 tightening strip threaded in the through-conduit, extending along at least a portion of the length of the cuff band; and at least two directing elements. The tightening strip may be stretched along the at least two directing elements and the through-conduit of the gear wheel. The gear assembly may be configured to tighten the cuff band when driven in a first direction and to untighten the cuff band when driven in a second direction.

Description

AUTOMATIC TOURNIQUET AND A METHOD OF CONTROLLING SAMECROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority from IL Patent Application No. 309420, filed on December 14, 2023, entitled “AUTOMATIC TOURNIQUET AND A METHOD OF CONTROLLING SAME”, the contents of which are incorporated by reference herein in their entirety.FIELD OF THE INVENTION

[0001] 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

[0002] 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.

[0003] 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 affectblood flow by tightening the tourniquet to a preset level, which may be a critical aspect especially for tourniquets with automatic tightening means.

[0004] 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 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 43 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.SUMMARY OF THE INVENTION

[0005] 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.

[0006] 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.

[0007] 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; at least one tightening strip threaded in the through-conduit, extending along at least a portion of the length of the cuff band; and at least two directing elements. In some embodiments, the tightening strip may bestretched along the at least two directing elements and the through-conduit of the gear wheel. In some embodiments, the at least one tightening strip is selected from; a wire, a band, a thread, and a combination thereof. In some embodiments, the gear assembly is configured to tighten the cuff band when driven in a first direction and to untighten the cuff band when driven in a second direction.

[0008] In some embodiments, the tightening strip and a portion of the cuff band may form a closed loop. In some embodiments, the tightening strip may from a loop. In some embodiments, the at least two directing elements may be selected from, rollers, pullies, pins, shafts, and loops. In some embodiments, each one of the at least two directing elements may be positioned at a respective end of the cuff band. In some embodiments, a first directing element may be located in proximity to the gear assembly, and at least one second directing element is located on the cuff band. In some embodiments, the tourniquet may further include two second directing elements located on the cuff band. In some embodiments, a portion of the tightening strip may be fixed to a location on the cuff band.

[0009] In some embodiments, the gear assembly may further include gear wheel comprises a grooved rim; and wherein the through-conduit at least partially goes through 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 may further comprise 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 may further include: 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 may be 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 may be 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 whereinthe 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 may be designed to cause the tourniquet to tighten to form a target pressure on a limb.

[0013] In some embodiments, the tourniquet further may further include: 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 may be 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.

[0016] In some embodiments, the controller may be 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 may further be 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.

[0017] In some embodiments, the tourniquet may further include a display and wherein the controller is configured to display on the display a period at which the pressure is applied on the limb.

[0018] In some embodiments, the tourniquet may further include a manual fast-release unit. In some embodiments, the gear assembly comprises locking mechanism preventing rotation of the gear assembly in the second direction.

[0019] Some additional aspects of the invention may be directed to a garment comprising the automatic tourniquet according to any one of the embodiments disclosed herein.

[0020] 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.

[0021] In some embodiments, the method may further include 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.

[0022] In some embodiments, the method may further include, 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.

[0023] In some embodiments, the predefined threshold may be determined experimentally.

[0024] In some embodiments, the method may further include generating the typical power consumption profile for specific location at a specific limb.

[0025] In some embodiments, the method may further 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 comprises a power provision duration required to tighten the tightening strip around the determined type of limb to a desired level of tension.

[0026] In some embodiments, the method may further 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 signal.

[0027] In some embodiments, the gear assembly may include 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 pulselike manner, when the amount of the consumed electrical power reaches the predefined threshold.

[0028] In some embodiments, the method may further include: 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

[0029] The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, 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:

[0030] Figs. 1A-1B are illustrations of a tourniquet applied on a limb, and a perspective view of the tourniquet according to some embodiments of the invention;

[0031] Figs. 1C-1D are illustrations of a top view of two optional tourniquets according to some embodiments of the invention;

[0032] Fig. IE is an image of a gear assembly and a motor to be included in a tourniquet according to some embodiments of the invention;

[0033] Fig. IF is an exploded top view of a tourniquet according to some embodiments of the invention;

[0034] Fig. 1G is an exploded bottom view of a tourniquet according to some embodiments of the invention;

[0035] Fig. 2 is a block diagram of a tourniquet according to some embodiments of the invention;

[0036] Fig. 3 is a flowchart of a method of controlling an automatic tourniquet according to some embodiments of the invention; and

[0037] 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.

[0038] 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

[0039] 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.

[0040] 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 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 combinedwith 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] Reference is now made to Figs. 1A and IB are illustrations an automatic tourniquet applied on a limb and a perspective view of the tourniquet, 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, and may further include a display 56 for displaying information, as discussed herein below with respect to Fig. 2.

[0046] Reference is now made to Figs. 1C and ID which are illustrations of a top view of two optional tourniquets according to some embodiments of the invention.

[0047] Cuff band 10 may include a cuff strip 11 that may be any suitable band, for example, a band used in commercial tourniquets (e.g., CAT) having a width of approximately 25 mm. Tourniquet 100 may further include at least one tightening strip 30 threaded in the through-conduit 21, extending along at least a portion of the length of cuff band 10. In some embodiments, at least one tightening strip 30 may be selected from; a wire, a band, a thread, and a combination thereof.

[0048] In some embodiments, tourniquet 100 may further include at least two directing elements 15, 16, 16a, and / or 16b. In some embodiments, tightening strip 30 may be stretched along at least two directing elements 15, 16, 16a, and / or 16b and the through- conduit 21 of gear wheel 22. In some embodiments, gear assembly 20 may be configured to tighten cuff band 10 when driven in a first direction and to untighten the cuff band when driven in a second direction.

[0049] In some embodiments, at least two directing elements 15, 16, 16a, and / or 16b may be selected from, rollers, pullies, pins, shafts, and loops, for example, the rollers or pins 15 and 16 illustrated in Fig. 1C, or pin 15 and loops 16a, and 16b illustrated in Fig. ID. Referring to Fig. 1C which is a schematic illustration of a top view of a tourniquet according to some embodiments of the invention, Tourniquet 100 may 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, For example, tightening strip 30 may form a loop and may be positioned so as to be engaged with grooved rim 26 (illustrated in Fig. IE) during tightening, but be disengaged when untightened, e.g., tightening strip 30 may enter rim 26 via hole 23 a and lead by circumferential groove 25 to be exit from hole 23b (illustrated in Fig. IE). In some embodiments, strip 30 is freely threaded in through- conduit 21 and may slide along through-conduit 21, in an untightened state. In some embodiments, any anchoring of strip 30 to gear assembly 20 is avoided.

[0050] In some embodiments, tourniquet 100 may include at least one pair of directing elements 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 directing elements 15 and 16 and threaded underneath gear 22, for example, when automatic tourniquet 100 is placed on a limb 5.

[0051] In some embodiments, cuff band 10 may further include fastening means 12 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.

[0052] Referring now to Fig. ID which is a schematic illustration of a top view of another tourniquet according to some embodiments of the invention. Tourniquet 100 may include cuff band 10, which includes a cuff strip 11. Gear assembly 20 may be attached to the cuff band 10 and may include gear wheel 22 having through-conduit 21 extending through gear wheel 22. Tourniquet 100 may feature at least one tightening strip 30 threaded through the through-conduit 21, extending along at least a portion of the length of the cuff band 10. Tightening strip 30 may be stretched along at least two loops-like directing elements 16a and 16b, positioned on the cuff band 10, and a pin-like directing element 15, located in proximity to gear assembly 22. Additionally, a portion of tightening strip 30 may be fixed to a location on cuff band 10 via attachment means 17. A nonlimiting design of this tourniquet is sown in Figs. IF and 1G.

[0053] Reference is now made to Fig. IE which is an image of a nonlimiting example for a gear assembly, according to some embodiments of the invention.

[0054] 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. IB 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 mayfurther include a grooved rim 26 attached to gear wheel 22. As shown grooved rim 26 comprises exit / entry holes 23a and 23b and circumferential groove 25.

[0055] 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.

[0056] In some embodiments, actuating means 40 may include an electric motor, as discussed in detail with respect to Fig. 3.

[0057] In some embodiments, gear assembly 20 may be configured to tighten a loop formed by tightening strip 30 with / without cuff strip 11, when driven in a first direction and to untighten the loop when driven in a second direction. Accordingly, the threading of tightening strip 30 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.

[0058] In some embodiments, gear assembly 20 may be designed to cause tourniquet 100 to tighten to form a target pressure on limb 5, for example, between of 250 to 350 mm Hg.

[0059] In some embodiments, gear assembly 20 may comprise a locking mechanism (not illustrated) preventing rotation of the gear assembly in the second direction.

[0060] In some embodiments, tourniquet 100 may further include a manual fastrelease 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 2O.Reference is now made to Figs. IF and 1G which are illustrations of an exploded top view and exploded bottom view of a nonlimiting example for a tourniquet design according to some embodiments of the invention.

[0061] Tourniquet 100 may include a gear assembly 20 attached to the cuff band, comprising a gear wheel 22 (e.g., a worm gear) having through-conduit 21 extending through the gear wheel, and a worm screw 28 operatively engaged with worm gear 22. Worm screw 28 is axially connected and actuated by actuating means 40 (e.g., an electric motor).

[0062] Tightening strip 30 (e.g., a wire) may be threaded in through-conduit 21, and stretched between directing element 15 (e.g., a pine shown in Fig. 1G) located in proximity to gear assembly 20 and directing element 16a (e.g., a roller / shaft) at two locations. In order to closed a loop, tightening strip 30 may be fixed to cuff strip 11 by attachment means 17. In some embodiments, tightening strip 30 may lead by circumferential groove 25 between the entrance and the exit from through-conduit 21.

[0063] In some embodiments, gear assembly 20 may be covered by one or more gear assembly covers 20a, 20b, 20c, and 20d. In some embodiments, cuff band 10 may include a cuff band cover 10a, covering the portion of cuff band comprising directing element 16a, attachment means 17, and the portion of tightening strip 30, stretched therethrough.

[0064] Tourniquet 100 may further include fastening means 12 and 13, designed for fast release of tourniquet 100. Also shown in Figs. IF and 1G are button 55 and display 56.

[0065] Reference is now made to Fig. 2, which is a block diagram of tourniquet 100 according 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, located, for example, between cover 20a and cover 20b, illustrated in Figs. IF and 1G.

[0066] 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.

[0067] 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.

[0068] In some embodiments, tourniquet 100 may further include an activation button 55 (illustrated also in Figs. 1A, IB, and IF) for activating actuating means 40 to rotate worm screw 28 to wrap strip 30 around rim 26 in order to tighten cuff band 10 around limb 5.

[0069] In some embodiments, tourniquet 100 may further include a battery charger 62 and a safety switch 64 for preventing accidental activation of the device. Therefore, onlyafter 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.

[0070] 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 and or display 56. LEDs 54 and / or display 56 may provide various visual information. For example, controller 50 may use LEDs 54 and / or display 56 to show the amount of time tourniquet 100 is being tightened on the limb. For example, controller 50 may include an internal clock 57 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.

[0071] 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.

[0072] 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.

[0073] In some embodiments, tourniquet 100 may further include one or more sensors 70 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 thelike. Such a flexible sensor may easily fit or adjust to the shape of the limb, thus may be assembled on the cuff band 10.

[0074] 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.

[0075] Additionally or alternatively, in some embodiments, controller 50 may be configured to receive from DC motor driver 42 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.

[0076] 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 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.

[0077] In some embodiments, controller 50 may further be configured to control electrical motor 41 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.

[0078] 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.

[0079] 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.

[0080] 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 100 around limb 5.

[0081] 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, the user may press activation button 55, therefore controller 50 may receive the signal to operate the automatic tourniquet.

[0082] 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 22 and groove rim 26 to rotate in a first direction, thus causing tightening strip 30 to wrap around rim 26 (inside groove 25). The wrapping of tightening strip 30, may shorten the length of a loop comprising tightening strip, thereby tightening cuff band 10 over limb 5. In some embodiments, during the rotating and wrapping act, tightening strip 30 may slide in and / or roll over directing elements 15.16, 16a and 16b, thereby ensuring a uniform tension along tightening strip 30. In some embodiments, forming a uniform tension along tightening strip 30 may ensure forming a uniform pressure on limb 5.

[0083] 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 asignal representing at least the voltage and / or the current consumed by motor 41 and determining the power consumption based on the signal.

[0084] 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.

[0085] In step 340, the method may include halting the electric motor when an amount of the consumed electrical power reaches a predefined threshold.

[0086] 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.

[0087] In some embodiments, the method may include analyzing, after a predetermined amount of time, 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) a sequence of tightening pulses may be provided by the motor. Therefore, the method may further comprise operating electrical motor 41 to provide torque in a pulse-like manner, when the amount of the consumed electrical power reaches the predefined threshold.

[0088] 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 associatedwith 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 be 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.

[0089] In some embodiments, the method may further include generating a typical power profile for a specific location at a specific limb, for example, upper or lower leg, upper or lower arm and the like.

[0090] 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 41 may be determined based on a signal indicative of the blood pressure in the limb received from sensor 70.

[0091] 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.

[0092] 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 beundetected, 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.

[0093] 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.

[0094] The present invention further represents a method of controlling an automatic tourniquet that provides 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.

[0095] 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.

[0096] 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.

[0097] 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

CLAIMS1. 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 tightening strip threaded in the through-conduit, extending along at least a portion of the length of the cuff band; and at least two directing elements; wherein the tightening strip is stretched along the at least two directing elements and the through-conduit of the gear wheel; and wherein the gear assembly is configured to tighten the cuff band when driven in a first direction and to untighten the cuff band when driven in a second direction.

2. The tourniquet of claim 1, wherein the at least one tightening strip is selected from; a wire, a band, a thread, and a combination thereof.

3. The tourniquet of claim 1 or claim 2, wherein the tightening strip and a portion of the cuff band form a closed loop.

4. The tourniquet of claim 1 or claim 2, wherein the tightening strip from a loop.

5. The tourniquet of any one of claims 1 to 4, wherein the at least two directing elements are selected from, rollers, pullies, pins, shafts, and loops.

6. The tourniquet of any one of claims 1 to 5, wherein each one of the at least two directing elements is positioned at a respective end of the cuff band.

7. The tourniquet of any one of claims 1 to 6, wherein a first directing element is located in proximity to the gear assembly, and at least one second directing element is located on the cuff band.

8. The tourniquet of claim 7, comprising two second directing elements located on the cuff band.

9. The tourniquet of any one of claims 1 to 8, wherein a portion of the tightening strip is fixed to a location on the cuff band.

10. The tourniquet of any one of claims 1 to 9, wherein the gear wheel comprises a grooved rim; and wherein the through-conduit at least partially goes through a groove of the grooved rim.

11. The tourniquet of claim 10, wherein the grooved rim comprises a circumferential groove for leading the tightening strip.

12. The tourniquet according to any one of claims 1-11, 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.

13. The tourniquet according to any one of claims 1-12 wherein the cuff band comprises: a cuff strip; and fastening means positioned at ends of the cuff strip.

14. The tourniquet according to any one of claims 1-13, wherein the actuating means are hand-driven means.

15. The tourniquet according to any one of claims 1-14, 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.

16. The tourniquet according to any one of claims 1-15, wherein the gear assembly is designed to cause the tourniquet to tighten to form a target pressure on a limb.

17. The tourniquet according to any one of claims 1-16, further comprising one or more sensors configured to provide a signal indicative of the tightening of the tourniquet on a limb; and a controller in operative connection with said one or more sensors and the electric motor.

18. The tourniquet of claim 17, wherein the controller is configured to control the electrical motor to provide a rotary torque to the gear assembly based on the signal.

19. The tourniquet according to any one of claims 17-18, further comprising a coupling connector for coupling high-frequency EM energy with high-voltage ormedium- 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.

20. The tourniquet according to any one of claims 17-19, wherein the controller is configured to control the electrical motor to provide rotary torque to the gear assembly, in a predetermined sequence.

21. The tourniquet according to any one of claims 17-20, wherein the controller is further configured to operate the electrical motor to provide torque in a pulselike manner, when the calculated electrical power reaches a predefined power consumption threshold.

22. The tourniquet according to any one of claims 17-21, wherein the controller is further configured to: monitor at least one of the 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.

23. The tourniquet according to any one of claims 17-22, further comprising: a display and wherein the controller is configured to display on the display a period at which the pressure is applied on the limb.

24. The tourniquet according to any one of claims 1-23, further comprising a manual fast-release unit.

25. The tourniquet according to any one of claims 1-24, wherein the gear assembly comprises locking mechanism preventing rotation of the gear assembly in the second direction.

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

27. 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 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 tightening strip and configured to tighten the tightening strip when driven, wherein tightening the tightening strip comprises directing the tightening strip around at least two directing elements; 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.

28. The method of claim 27, further comprised determining the type of the limb, based on the monitored electrical power; and setting the predefined threshold, based on the determined type of the limb.

29. The method of claim 27, 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.

30. The method of any one of claims 27 to 29, wherein the predefined threshold is determined experimentally.

31. The method according to any one of claims 27 to 30, further comprising: generating a typical power consumption profile for a specific location on a specific limb.

32. The method according to any one of claims 27 to 31, further comprising:analyzing, after a predetermined amount of time, monitored of at least one of, a voltage and a 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.

33. The method according to any one of claims 27 to 32, 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.

34. The method according to any one of claims 27-33, 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.

35. The method according to any one of claims 27-34, 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.

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