阅读说明：本技术 用于将针***非均质材料中、尤其是用于静脉导管***的手持装置 (Handheld device for inserting a needle into a heterogeneous material, in particular for intravenous catheterization ) 是由 莱昂纳多·塞拉德马托斯 成卓奇 布莱恩·L·戴维斯 达尔文·戈登·卡尔德威尔 于 2018-05-28 设计创作，主要内容包括：一种用于将针(16)的尖端(18)精确地定位到血管(V)中的期望目标位置处的手持设备(10),其包括：壳体(12),其适于由操作者手持；轴(14),轴沿着纵向轴线(x)延伸并且在其远端处承载针(16),轴(14)安装在壳体(12)中；分离或致动装置(22,22’),其分别能够在操作上将轴(14)与壳体(12)分离；检测装置(26),其被布置为提供指示针尖(18)必须插入其中的血管的至少一个物理特性的信号；以及控制装置(24),其与分离或致动装置(22,22’)和检测装置(26)在操作上连接,并且被配置成基于从检测装置(26)接收的信号来确定针尖(18)是否已经到达目标位置,并且分别操作分离或致动装置(22,22’)以使轴(14),并且因此使针(16)与壳体(12)分离,或者使轴(14),并且因此使针(16)相对于壳体(12)主动地移动。(A handheld device (10) for accurately positioning a tip (18) of a needle (16) at a desired target location in a blood vessel (V), comprising: a housing (12) adapted to be held by an operator; a shaft (14) extending along a longitudinal axis (x) and carrying a needle (16) at its distal end, the shaft (14) being mounted in the housing (12); -separating or actuating means (22, 22') respectively able to operatively separate the shaft (14) from the housing (12); a detection arrangement (26) arranged to provide a signal indicative of at least one physical characteristic of a blood vessel into which the needle tip (18) must be inserted; and control means (24) operatively connected with the detachment or actuation means (22, 22') and the detection means (26) and configured to determine whether the needle tip (18) has reached the target position based on a signal received from the detection means (26) and to operate the detachment or actuation means (22, 22') to detach the shaft (14) and thus the needle (16) from the housing (12) or to detach the shaft (14) and thus the needle (16) actively relative to the housing (12), respectively.)

1. A hand-held device (10) for inserting a needle (16) into a heterogeneous material, such as a blood vessel (V), comprising:

a housing (12) adapted to be held by an operator;

a shaft (14) extending along a longitudinal axis (x) and carrying the needle (16) at its distal end, the shaft (14) being mounted in the housing (12) and generally coupled with the housing (12) so as to move with the housing as a single piece along the longitudinal axis (x); and

a separation device (22) operable to separate the shaft (14) from the housing (12) such that the shaft (14) is movable relative to the housing along the longitudinal axis (x);

characterized in that the device further comprises:

a detection device (26) arranged to provide a signal indicative of at least one physical characteristic of a material into which the needle tip (18) must be inserted; and

a control device (24) operatively connected with the separation device (22) and the detection device (26) and configured to determine whether the needle tip (18) has reached the target position based on a signal received from the detection device (26) and to operate the separation device (22) to separate the shaft (14) from the housing (12) and thus the needle (16) from the housing (12).

2. The device of claim 1, wherein the decoupling device (22) is configured to normally clamp the shaft (14) to couple the shaft to the housing (12) and operable to release the shaft (14) to allow the shaft to move relative to the housing (12) along the longitudinal axis (x).

3. The device of claim 1 or 2, wherein the disengagement device (22) comprises an electrically-operated clutch operable between an engaged position in which the electrically-operated clutch clamps the shaft (14) such that the shaft (14) is coupled to the housing (12); in the disengaged position, the electrically-operated clutch releases the shaft (14), thereby allowing the shaft (14) to move relative to the housing (12).

4. The device of claim 1 or 2, wherein the separation device (22) comprises a tubular pressurized container mounted in the housing (12) so as to move as a single piece therewith and defining a central passage (34) through which the shaft (14) extends, whereby the container clamps the shaft (14) within the passage (34) when pressurized and does not clamp the shaft (14) when deflated, thereby allowing the shaft (14) to move relative to the container.

5. A hand-held device (10) for inserting a needle (16) into a heterogeneous material, such as a blood vessel (V), comprising a housing (12) adapted to be held by an operator and a shaft (14) extending along a longitudinal axis (x) and carrying said needle (16) at its distal end, said shaft (14) being mounted in said housing (12) and generally coupled with said housing (12) so as to move together with said housing as a single piece along said longitudinal axis (x),

characterized in that the device further comprises:

an actuating device (22') for actively moving the shaft (14) relative to the housing (12) in either direction along the longitudinal axis (x);

a detection device (26) arranged to provide a signal indicative of at least one physical characteristic of a material into which the needle tip (18) must be inserted; and

a control device (24) operatively connected with the actuation device (22') and the detection device (26) and configured to determine whether the needle tip (18) has reached the target position based on a signal received from the detection device (26) and to operate the actuation device (22') to move the shaft (14) relative to the housing (12) and thus the needle (16) relative to the housing (12).

6. The device according to claim 5, wherein the actuation means (22') is formed by a motorized linear mechanism (36, 38, 40) arranged to move the shaft (14) back and forth along the longitudinal axis (x) under the control of the control means (24) to hold the needle tip (18) in the target position to automatically compensate for any forward or backward movement of the housing (12) relative to the non-homogeneous material caused by the operator.

7. The device according to claim 6, wherein the motorised linear mechanism (36, 38, 40) comprises an electric motor (36) and a motion conversion mechanism (38, 40) arranged to convert a rotary motion generated by the electric motor (36) into a translational motion of the shaft (14) along the longitudinal axis (x).

8. The apparatus of any of claims 5 to 7, further comprising: a catheter (20) mounted around the needle (16) and an operating handle (46) movable relative to the housing (12) in a direction parallel to the longitudinal axis (x) for inserting the catheter (20) into the heterogeneous material.

9. The device according to claim 8, wherein the actuation device (22') is arranged to: when the needle tip (18) has reached the target location and the operating handle (46) is moved relative to the housing (12) to insert the catheter (20) into the heterogeneous material, the shaft (14) is moved relative to the housing (12) in a direction opposite to the direction of movement of the operating handle (46) to withdraw the needle (16) from the heterogeneous material.

10. The device according to claim 8 or claim 9, further comprising a support member (48) configured to support the device (10) on the heterogeneous material and being slidably mounted relative to the housing (12) in a direction parallel to the longitudinal axis (x), and a clutch device (52) switchable between a first position in which the clutch device allows the housing (12) to freely slide relative to the support member (48) and a second position in which the clutch device couples the housing (12) with the support member (48) thereby preventing relative movement of the housing (12) relative to the support member (48).

11. The device according to any one of the preceding claims, wherein the detection device (26) is configured to sense an acoustic or near-acoustic signal of the needle (16) or an electrical resistance between the needle tip (18) and the shaft (14).

Technical Field

The present invention relates to a handheld device for inserting a needle into a heterogeneous material, in particular for intravenous catheterization.

Background

EP0730880A, on which the preambles of independent claim 1 and independent claim 5 are based, discloses a manual catheter insertion device provided with a needle retraction actuation mechanism. The purpose of this known device is to improve the catheterization process, as it helps the medical technician to correctly handle the needle to avoid contaminated needle stick injuries. The device includes a generally hollow barrel housing a needle hub. The needle is secured to the distal end of the hub and is aligned to extend through an opening in the distal end of the barrel. The needle extends through the catheter hub and a catheter secured to the catheter hub. The device further includes a spring disposed within the barrel lumen to engage the needle hub to urge the needle hub toward the proximal end of the barrel. The latch actuator is releasably engaged with the catheter hub. A latch cooperating with the latch actuator is movable between a first position in which the latch holds the hub adjacent the distal end of the barrel and a second position; in the second position, the latch allows the spring to push the hub to the proximal end of the barrel. The operator may experience discomfort during needle insertion or during post-penetration needle extraction due to vibration caused by the actuation of the spring. Furthermore, this known device does not guide the insertion of the needle into the material.

Disclosure of Invention

It is therefore an object of the present invention to provide a hand-held device for accurately positioning the tip of a needle in a non-homogenous material, in particular for intravenous catheter insertion, which is safer and more comfortable to use than the above mentioned prior art.

The objects of the invention and others are fully achieved according to the invention by means of a device having the features set out in independent claim 1 and in independent claim 5.

Advantageous embodiments of the invention form the subject of the dependent claims, the content of which is intended to form an integral part of the following description.

In short, the invention is based on the following idea: providing an apparatus, the apparatus comprising: a separation or actuation means operatively arranged between the needle and the housing for separating the needle from the housing such that the needle does not move as a single piece along the longitudinal axis of the housing together with the housing or for moving the needle in a controlled manner along the longitudinal axis of the needle in an opposite direction with respect to the housing during insertion; also included is a detection device configured to detect that the needle tip has reached a target location in the heterogeneous material; and control means operatively connected to said separating or actuating means and to said detecting means, and configured to operate said separating or actuating means upon detection by said detecting means that the needle tip has reached the target position.

By virtue of this structure, the device of the invention allows to introduce the needle into the target heterogeneous material, thus stopping the needle tip in the correct position or retracting it, even if the operator moves the housing of the device forward into the material. This is particularly helpful when performing e.g. intravenous catheter insertion, especially for difficult patients, such as children, elderly patients or diabetics. Furthermore, with such a device, the operator requires less training to obtain good injection results.

Drawings

Further characteristics and advantages of the invention will become apparent from the following detailed description, given by way of non-limiting example only, with reference to the accompanying drawings, in which:

fig. 1 schematically shows a hand-held device for inserting a needle into a heterogeneous material according to the present invention;

fig. 2a and 2b are schematic views showing a first embodiment of a device according to the invention in a first operating state in which the needle is coupled to the housing of the device and in a second operating state, respectively; in a second state, the needle is separated from the housing;

fig. 3 is a schematic view showing a second embodiment of the device according to the invention in the second operating condition described above;

figures 4a and 4b are schematic views showing a third embodiment of the device according to the invention in the first and second operating conditions described above, respectively;

FIG. 5 is a schematic diagram showing a fourth embodiment of the apparatus according to the present invention;

6a, 6b and 6c are schematic views showing a fifth embodiment of the device according to the invention in a first, second and third operating state, respectively, wherein in the first operating state both the needle and the catheter are coupled to the handle and the housing is freely movable along the longitudinal axis of the needle relative to the support member; in a second operating state the needle tip has reached the blood vessel and the body is locked to the support member; in a third operating condition with the body still locked to the support member, the handle is advanced to move the catheter further into the blood vessel and simultaneously retract the needle;

figures 7a, 7b and 7c are schematic views showing a sixth embodiment of the device according to the invention in said first, second and third operating conditions, respectively; and

fig. 8a, 8b and 8c are schematic views showing a seventh embodiment of the device according to the invention in said first, second and third operating states, respectively.

Detailed Description

The invention will be described hereinafter with particular reference to a catheterization procedure, i.e. the application of a catheter into a blood vessel. However, this particular application should not be construed as limiting the scope of the invention as the invention may be used in many other applications such as tissue biopsy (e.g. from brain, liver, etc.), brachytherapy (i.e. insertion of radioactive seeds into a patient for cancer treatment), blood sampling (i.e. insertion of needles into blood vessels), or spinal cord puncture.

Fig. 1 shows a very schematic representation of a handheld catheter insertion device (hereinafter simply referred to as "device") according to the present invention, wherein the device is generally indicated at 10.

Referring to fig. 1, the apparatus 10 basically comprises: a body or housing 12 (hereinafter referred to simply as a housing) sized to be grasped by an operator's hand; and a shaft 14 partially housed within the housing 12 and carrying at its distal end a needle 16 having a tip 18 and a catheter 20 disposed around the needle 16. The longitudinal axis of shaft 14 is designated x and the longitudinal axis of needle 16 is designated x'. The longitudinal axes x and x' are parallel to each other and may also coincide with each other (as in the embodiment shown in fig. 1).

The shaft 14 is typically coupled with the housing 12 such that an operator may move the shaft 14 as a unit with the housing 12, however, once the needle tip 18 reaches a target location, such as a blood vessel, the shaft 14 may be separated from the housing 12 by a unit 22 (in this case, a separating unit) such that the shaft 14 is no longer coupled with the housing 12 and is therefore free to move relative to the housing 12 in the direction of its longitudinal axis x. Once the shaft 14 and needle 16 carried by the shaft 14 are separated from the housing 12, possible further forward movement of the housing 12 by the operator is no longer transmitted to the needle 16, and thus the needle tip 18 remains in the target position regardless of possible movement of the housing 12 by the operator (intentionally or unintentionally).

The device 10 further comprises a control unit 24 (e.g. a microcontroller), the control unit 24 being configured to control the detachment unit 22 to detach the shaft 14 from the housing 12 when the needle tip 18 has reached the target position (that is to say, in the case of a catheter insertion device, a blood vessel), and thus also to detach the needle 16 and the catheter 20 carried by the shaft 14 from the housing 12.

In order to inform the control unit 24 of the arrival of the needle tip 18 at the target location, the device 10 further comprises a sensor unit 26, the sensor unit 26 being arranged to measure a physical property of the material at the needle tip 18, such as resistance, pressure, color, temperature, etc., or to measure vibration, sound, force variations, etc., and to send a corresponding signal to the control unit 24. Based on the signal received by the sensor unit 26, the control unit 24 is able to distinguish between different materials at the needle tip 18 to determine whether the needle tip 18 has reached a target location. For example, in the case of a sensor unit 26 made as an impedance sensing circuit and a target site constituted by a blood vessel, the control unit 24 will analyze the impedance signal provided by the sensor unit 26 and determine whether the impedance signal is in the range of blood. In the affirmative, the control unit 24 will command the detaching unit 22 to detach the shaft 14 from the housing 12, and thus also the needle 16 from the housing 12.

The device 10 is preferably battery powered by an embedded rechargeable or replaceable battery pack (not shown). Alternatively, the device 10 may be powered by an external DC adapter.

Referring now to fig. 2a and 2b, a first embodiment of the invention is shown in which the device 10 is configured to insert a catheter 20 into a vein V. Fig. 2a shows the device 10 before the needle 16 has penetrated the vein V, while fig. 2b shows the device 10 once the needle 16 has penetrated the vein V and the needle tip 18 is thus within the vein V.

According to this embodiment, the disengagement unit 22 includes an electrically-powered clutch that normally engages the shaft 14 and thus clamps the shaft 14, typically such that the shaft 14 is coupled to the housing 12 (fig. 2 a). When activated, the electrically powered clutch releases the shaft 14, allowing the shaft 14 to move freely along the longitudinal axis x of the shaft 14 in at least one direction (fig. 2b) relative to the housing 12, and thus the needle 16 and catheter 20 along with the shaft move freely along the longitudinal axis x of the shaft 14 in at least one direction (fig. 2b) relative to the housing 12, such that if the operator moves the housing 12 further toward the vein V, the shaft 14 may retract inside the housing 12, allowing the needle tip 18 to remain in the target position in the vein V.

In the case of the sensor unit 26, it includes an impedance sensor housed in a concentric electrode needle 28 to measure the electrical impedance between the needle tip 18 and the needle shaft. The concentric electrode needle 28 is inserted onto a connector element 30, which in turn is mounted on the distal end of the shaft 14 by a connecting member 32, such that the concentric electrode needle 28 is drivingly connected to the shaft 14. The sensed electrical impedance signal is transmitted from the sensor unit 26 to the control unit 24 so that the control unit 24 can determine whether the needle tip 18 has reached the vein and, if so, activate the electrically-operated clutch to disengage the shaft 14 from the housing 12.

Fig. 3 shows a second embodiment of the invention, in which parts and elements identical or corresponding to fig. 2a and 2b are indicated with the same reference numerals, which differs from the first embodiment of fig. 2a and 2b in that the sensor unit 26 is arranged to detect a sound or near-acoustic (near-acoustic) signal generated by venipuncture, a so-called "pop" sound or needle vibration described by the physician.

In this case, the sensor unit 26 includes a microphone for acquiring and using acoustic signals and a suitable signal processing system configurator for distinguishing sounds produced upon penetration of the vein from other noise produced upon penetration of adjacent tissue. The sensor unit 26 may also include a filter configured to remove these other noises and thus improve the signal-to-noise ratio. Such an acoustic-based detection system may be used as an alternative to the impedance-based detection system described above in connection with the first embodiment of fig. 2a and 2b, or as a further detection system in addition to the above impedance-based detection system.

Referring now to fig. 4a and 4b, a third embodiment of the invention is shown in fig. 4a and 4b, in which parts and elements identical or corresponding to those of fig. 2a and 2b are indicated by the same reference numerals, which embodiment differs substantially from the first embodiment of fig. 2a and 2b only in the structure of the separation unit 22.

In the third embodiment, in practice, the separation unit 22 is formed by a tubular pressurized container which is mounted in the housing 12 so as to move as a single piece therewith, and the separation unit 22 defines a central passage 34 through which the shaft 14 extends. When pressurized, the container clamps the shaft 14 within the channel 34 such that the shaft 14 is secured to the housing 12 (fig. 4 a). However, when deflated to a low pressure (e.g. due to piercing), the container no longer grips the shaft 14, and the shaft 14 is therefore free to move relative to the container, and thus relative to the housing 12 (fig. 4 b). In this case, when the control unit 24 determines that the needle tip 18 has reached the target position based on the signal received from the sensor unit 26, the control unit 24 controls the separation unit 22 so as to cause deflation of the pressurized container. Thus, even if the operator pushes the housing 12 further towards the vein V, or more generally towards the material in which the needle tip 18 must be inserted, the needle tip 18 does not move with the housing 12, but stays in the target position.

Referring now to fig. 5, in which parts and elements identical or corresponding to those in the previous figures have been given the same reference numerals, according to another embodiment of the invention, the device comprises an actuation unit 22 'instead of the separation unit 22, the actuation unit 22' being formed by a motorized linear mechanism arranged to move the shaft 14 back and forth along the longitudinal axis x under the control of the control unit 24 to maintain the needle tip 18 in a target position, for example a fixed position within the vein V, to automatically compensate for any possible forward or backward movement of the housing 12 produced by the user.

The motorised linear mechanism may comprise, for example, an electric motor 36 and a screw-nut mechanism for converting the rotary motion of a screw 38 driven in rotation by the motor 36 into a translational motion of a nut 40 along an axis coincident with, or more generally parallel to, the longitudinal axis x of the shaft 14, the nut 40 being fixed to the shaft 14 or alternatively being integral with the shaft 14. By controlling the rotation of the motor 36 in one direction or the opposite direction, the control unit 24 moves the needle 16 back and forth relative to the housing 12 in order to automatically insert or withdraw the needle 16 from the vein V and/or actively maintain the needle 16 in a fixed position within the vein V, independent of any possible movement of the housing 12 by the user. In order for the control unit 24 to suitably control the motor 36 to maintain the needle 16 in a fixed position, thereby compensating for any possible movement of the housing 12 by the user, the device 10 further comprises an axial force sensor 42 or a position sensor 44 to sense the force exerted by the user on the housing 12 once the needle tip 18 has reached its target position in the vein V.

According to the illustrated embodiment, the device 10 is also capable of withdrawing the needle 16 from the vein V as the catheter 20 is inserted into the vein V. In this case, the motorized linear mechanism is activated by the control unit 24 to withdraw the shaft 14, and therefore also the needle 16, at a higher speed than the forward movement of the housing 12 caused by the user, so that once the needle tip 18 has penetrated the vein, the needle 16 is withdrawn from the vein V, while at the same time the catheter 20 is pushed forward by the housing 12 and thus enters the vein V.

Fig. 6a to 6c, 7a to 7c and 8a to 8c show further embodiments of the device according to the invention, in which parts and elements identical or corresponding to those in fig. 5 have been given the same reference numerals, the device comprising an actuation unit arranged to actively move the shaft and thus the needle back and forth relative to the housing to compensate for any possible movement of the housing, and in which the catheter can be inserted into the vein while the needle is withdrawn from the vein.

Referring first to the embodiment shown in figures 6a to 6c, the device 10 further comprises a handle 46 (or, alternatively, by a suitable linear actuator, such as an electromechanical linear actuator) and a support member 48 operable by a user, both of which are slidably mounted on the housing 12 so as to slide relative to the housing in a direction parallel to the longitudinal axes x and x'. The handle 46 is connected to the shaft 14 by a swing arm 50, the centre of which is hinged to the housing 12 at a pivot point F, and the opposite ends of which are hinged to the handle 46 and the shaft 14, such that longitudinal movement of the handle 46 in one direction relative to the housing 12 causes longitudinal movement of the shaft 14 in the opposite direction relative to the housing 12. The support member 48 may be coupled to the housing 12 by a clutch lever 52 hingedly mounted to the housing 12. The support member 48 is brought into contact with the material (e.g., the patient's skin) into which the needle tip 18 must be inserted in order to help support the device 10 during insertion of the needle 16 into the material.

As shown in fig. 5a, a forked locking member 54 operated by a solenoid 56 is operatively connected with the swing arm 50 to lock the swing arm and prevent the swing arm from rotating about its fulcrum F. The solenoid 56 is also configured to control movement of the clutch control lever 52 between a first operative position (fig. 6a) in which the clutch control lever 52 is not engaged with the support member 48 and therefore does not prevent sliding of the support member relative to the housing 12, and a second operative position (fig. 6b and 6 c); in the second operating position, the clutch lever 52 is engaged with the support member 48 to couple the support member to the housing 12.

When the solenoid 56 is deactivated, it holds the locking member 54 in the locking position in which the locking member 54 locks the swing arm 50. Meanwhile, the clutch control lever 52 is in the above-described first operating state. On the other hand, when the solenoid 56 is activated, it moves the clutch control lever 52 to the above-described second operating position, and at the same time moves the locking member 54 away from the locking position to allow the swing arm 50 to rotate about its fulcrum F.

When the solenoid 56 is deactivated (see fig. 6a), and thus when the swing arm 50 is locked by the locking member 54 and the clutch lever 52 is in the above-described first operating position, an operator acting on the handle 46 can move the needle 16 and catheter 20 towards the vein V while the support member 48 is in contact with the patient's skin, because the clutch control lever 52 allows the housing 12, and thus the shaft 14, to move relative to the support member 48.

Upon detecting by the sensor unit 26 that the needle tip 18 has reached the vein V, the control unit 24 activates the solenoid 56 such that the swing arm 50 is no longer locked by the locking member 54 and is therefore able to rotate about its fulcrum F, while the clutch control lever 52 moves to the second operative position to couple the support member 48 to the housing 12 (fig. 6 b). Thus, the needle 16 is prevented from advancing further into the vein V.

At this point, as shown in fig. 6c, the operator moves the handle 46 further forward (or, alternatively, by power from an embedded battery pack or from an external connection), causing, on the one hand, the catheter 20 to move correspondingly forward into the vein V, and, on the other hand, the pivoting movement of the swing arm 50 about the fulcrum F, thus withdrawing the needle 16 from the vein V.

Thus, the device of fig. 6a to 6c allows the following three different actions to be performed:

i) separating the needle 16 from the housing 12 to avoid passing over the target;

ii) withdrawing the needle 16; and

iii) inserting the catheter 20, which action is performed simultaneously with action ii).

The device 10 may be provided with an optional LED output (not shown) to indicate that the needle tip 18 has reached the target location as detected by the sensor unit 26. The LED output may also provide an indication regarding any of the following states of the device:

a) device 10 ready/not ready;

b) the needle 16 is coupled/decoupled to the housing 12;

c) the catheter 20 is locked/released; and

d) battery level.

The device may also be connected wirelessly or by wire to an external computer system (not shown) for transmitting in real time the measurements obtained by the sensor unit and/or internal parameters indicative of the operating state of the device and for remote control operation.

The embodiment of fig. 7a to 7c differs from the embodiment of fig. 6a to 6c mainly in that: as a swing arm for converting the translational movement of the handle 46 in one direction into a translational movement of the shaft 14 in the opposite direction, is replaced by a gear mechanism comprising a gear 58, which is idly and rotatably supported by the casing 12 and meshes both with a first rack 60 of the handle 46 and with a second rack 62 of the shaft 14; and the locking member 54 is made as a brake pad arranged to lock the gear 58 by exerting a friction torque on the gear 58. Also in this embodiment, the clutch control rod 52 and the locking member 54 are controlled by the solenoid 56 in the following manner: when the solenoid 56 is deactivated (fig. 7a), the clutch lever 52 is not engaged with the support member 48 and the locking member 54 locks the gear 58, whereas when the solenoid 56 is activated (fig. 7b and 7c), the clutch lever 52 is engaged with the support member 48 and the locking member 54 unlocks the gear 58.

Finally, fig. 8a to 8c show a further embodiment, which differs substantially from the embodiment of fig. 7a to 7c only in that: the gear mechanism as a means for converting translational movement of the handle 46 in one direction into translational movement of the shaft 14 in the opposite direction is replaced by a belt mechanism comprising a wheel 64 and a belt 66 attached at a first end thereof to the handle 46, the belt being passed around the wheel 64 and attached at an opposite end thereof to the shaft 14. Also in this case, the wheel 64 may be locked by the locking member 54 made as a brake pad.

As far as the sensor unit 26 is concerned, the description provided above with reference to the embodiments of fig. 2a and 2b and fig. 3 also applies to the other embodiments of the invention shown in fig. 4a to 8 c.

The advantages of the present invention over the prior art are apparent in view of the above description.

First of all, by means of the sensor unit of the invention, the invention allows to determine whether the needle tip has reached a target position, and by means of the separation or actuation unit, the invention allows to separate the needle from the housing of the device and thus avoid passing over the target, even if the operator moves the device further towards the material, or actively moves the needle back and forth with respect to the housing, the device of the invention allows the operator, even those who are not very skilled, to precisely position the needle tip in the desired position and to keep it in this position, thereby significantly reducing the working pressure of the operator, especially when difficult patients (such as children, elderly or diabetics) have to be treated.

Furthermore, the device of the invention has a light and compact structure, which facilitates the operation of the device by the operator and is also inexpensive to manufacture.

Naturally, the principle of the invention remaining the same, the embodiments and the constructional details may vary widely from those described and illustrated purely by way of non-limiting example, without thereby departing from the scope of the invention as defined in the appended claims.