CN211985552U

CN211985552U - Ligation device with high ligation precision

Info

Publication number: CN211985552U
Application number: CN202020268677.4U
Authority: CN
Inventors: 王强; 刘改杰
Original assignee: Henan Tuoren Medica Device Co ltd
Current assignee: Henan Tuoren Medica Device Co ltd
Priority date: 2020-03-06
Filing date: 2020-03-06
Publication date: 2020-11-24
Anticipated expiration: 2030-03-06

Abstract

The utility model discloses a ware is pricked to cover of high cover precision, include: the device comprises a handle, a controller, a display, a ligation component, a negative pressure mechanism, a position sensor and a length sensor, wherein the ligation component is used for sucking haemorrhoids and sleeving an elastic coil with an adjustable inner diameter on the haemorrhoids; the ligation component, the negative pressure mechanism, the position sensor, the length sensor and the display are in signal connection with the controller. This application has the ration and inhales the function, and the control inhales the length of the haemorrhoids of ligation subassembly, need not to rely on medical personnel's experience to fix a position the artery position in the anus intestines, reduces the misery that the maloperation brought for the patient, has promoted operation efficiency, and whole process develops, monitors in real time, improves the accuracy.

Description

Ligation device with high ligation precision

Technical Field

The utility model relates to the technical field of medical equipment, more specifically say, relate to a ware is pricked to cover of high cover precision.

Background

The common method for treating hemorrhoids adopts a ligation operation, and the principle is that a special rubber ring is sleeved and tied at the root or the base of an artery on the hemorrhoids, and the blood supply of the hemorrhoids is blocked by utilizing the elastic retraction force of the rubber ring, so that the hemorrhoids are necrotized, atrophied and shed, thereby achieving the purpose of healing; at present, the instruments for performing the ligation operation generally adopt a ligation device, which adsorbs the superior hemorrhoidal artery by vacuum and then sleeves the superior hemorrhoidal artery by elastic threads, so as to achieve the purpose of necrosis of the hemorrhoidal.

The existing ligation device on the market adopts a hand-held gun type, generally comprises a handle and a ligation component connected with the handle, wherein the ligation component comprises an inner cavity tube and a pushing sleeve, the pushing sleeve is controlled by the handle to move towards the front end of an inner cavity tube so as to push and sleeve an elastic wire wound at the front end of the inner cavity tube on an arteria haemorrhoids sucked into the inner cavity tube, and the ligation is completed by tightening and cutting the elastic wire. If the hemorrhoids are sucked too short, the hemorrhoids cannot be completely removed, namely the operation fails, and the operation needs to be carried out for a plurality of times, so that the pain of the patient caused by the operations is caused.

In summary, how to accurately position hemorrhoids and accurately measure the length of inhaled hemorrhoids is a problem to be solved by those skilled in the art.

SUMMERY OF THE UTILITY MODEL

In view of this, the present invention provides a ligation device with high ligation precision, which can be used to perform an operation to accurately position hemorrhoids and accurately measure the length of the inhaled hemorrhoids.

In order to achieve the above object, the present invention provides the following technical solutions:

a ligation device with high ligation precision comprises: the device comprises a handle, a controller, a display, a ligation component, a negative pressure mechanism, a position sensor and a length sensor, wherein the ligation component is used for sucking haemorrhoids and sleeving an elastic coil with an adjustable inner diameter on the haemorrhoids;

the ligation component is detachably arranged on the handle, the controller and the negative pressure mechanism are both arranged in the handle, the display is arranged outside the handle, and the position sensor and the length sensor are both arranged in the front end of the ligation component;

the ligation component, the negative pressure mechanism, the position sensor, the length sensor and the display are in signal connection with the controller.

Preferably, including being used for letting out the pressure release subassembly of ligation subassembly internal pressure, the pressure release subassembly includes pressure release key, pressure release mouth, pressure release spring, the pressure release mouth communicate in with the pipeline of ligation subassembly intercommunication, the pressure release key set up in on the pressure release mouth, the spring is used for the top the inside of pressure release key, so that the pressure release key is the pressure release when pushing down, the pressure release key with the pressure release mouth set up in on the handle.

Preferably, a sealing ring is arranged between the pressure relief key and the pressure relief opening.

Preferably, the length sensor is an infrared sensor, a mounting pipe is coaxially arranged in the center of the ligation assembly, and the infrared sensor is mounted at the front end of the mounting pipe.

The utility model provides a pair of ware is pricked to cover of high accuracy of pricking, include: the device comprises a handle, a controller, a display, a ligation component, a negative pressure mechanism, a position sensor and a length sensor, wherein the ligation component is used for sucking haemorrhoids and sleeving an elastic coil with an adjustable inner diameter on the haemorrhoids;

This scheme relies on position sensor development focus tissue artery, can pinpoint the haemorrhoids position, negative pressure mechanism produces the negative pressure, control ligation subassembly is inhaled after aiming at haemorrhoids, utilize length sensor's detection, can survey the length that inhales haemorrhoids, length sensor is with signal transmission to controller, the controller supplies the art person with length information transmission to the display to observe, control ligation subassembly is automatic overlaps the stretch coil on haemorrhoids, later tighten up the stretch coil and cut off the stretch line and can accomplish the ligation. According to the detection of the position sensor, the detection result is displayed on the display screen, and the image can be developed to facilitate observation of an operator.

This application has the ration and inhales the function, and the control inhales the length of the haemorrhoids of ligation subassembly, need not to rely on medical personnel's experience to fix a position the artery position in the anus intestines, reduces the misery that the maloperation brought for the patient, has promoted operation efficiency, and whole process develops, monitors in real time, improves the accuracy.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

Fig. 1 is a front side view of a ligation device with high ligation precision according to the present invention;

FIG. 2 is a partial front view of the ligation device with high ligation precision according to the present invention;

fig. 3 is a side perspective view of a ligation device with high ligation precision according to the present invention;

fig. 4 is a schematic view of a shearing mechanism provided by the present invention;

fig. 5 is an enlarged view of the shearing mechanism provided by the present invention;

fig. 6 is a schematic view of a wire rewinding mechanism provided in the present invention;

fig. 7 is an enlarged view of the take-up mechanism provided by the present invention;

fig. 8 is an internal structure view of the shearing mechanism according to the present invention.

In FIGS. 1-8:

1-shearing mechanism, 2-wire-rewinding mechanism, 3-near infrared sensing system, 4-elastic coil, 5-inner cavity tube, 6-pushing sleeve, 7-driving mechanism, 8-driving rod, 9-trigger, 10-threading hole, 11-sleeve, 12-blade, 13-elastic sheet, 14-strip-shaped chute, 15-cross bar, 16-handle, 17-elastic line, 18-second gear, 19-driving motor and 20-pushing rod.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

The core of the utility model is to provide a ligation device of high ligation precision, the ligation device of this high ligation precision is used to carry out the operation and can pinpoint haemorrhoids, accurate measurement inhale haemorrhoids length.

Referring to fig. 1 to 8, fig. 1 is a front side view of a ligation device with high ligation precision according to the present invention; FIG. 2 is a partial front view of the ligation device with high ligation precision according to the present invention; fig. 3 is a side perspective view of a ligation device with high ligation precision according to the present invention; fig. 4 is a schematic view of a shearing mechanism provided by the present invention; fig. 5 is an enlarged view of the shearing mechanism provided by the present invention; fig. 6 is a schematic view of a wire rewinding mechanism provided in the present invention; fig. 7 is an enlarged view of the take-up mechanism provided by the present invention; fig. 8 is an internal structure view of the shearing mechanism according to the present invention.

A ligation device with high ligation precision comprises: the device comprises a handle 16, a controller, a display, a ligation component, a negative pressure mechanism, a position sensor and a length sensor, wherein the ligation component is used for sucking hemorrhoids and sleeving an elastic coil 4 with adjustable inner diameter on the hemorrhoids;

the ligation component is detachably arranged on the handle 16, the controller and the negative pressure mechanism are both arranged in the handle 16, the display is arranged outside the handle 16, and the position sensor and the length sensor are both arranged in the front end of the ligation component;

It should be noted that the length sensor can be set as an infrared sensor, the infrared sensor is arranged in the front of the inner cavity of the ligation assembly, and the infrared sensor is arranged in the middle of the ligation assembly to realize that a preset distance is arranged between the infrared sensor and the front end of the ligation assembly, and the preset distance is used for accommodating the inhaled hemorrhoid tissue.

The position sensor can adopt a near-infrared sensing system 3, the near-infrared sensing system 3 comprises a camera and a main light source, the camera and the main light source are both arranged in an inner cavity tube 5 of the ligation assembly, and a first preset distance is arranged between the front end parts of the camera and the main light source and the inner cavity tube 5.

It should be noted that a first preset distance is provided between the near-infrared sensing system 3 and the front end of the inner lumen 5 for accommodating the hemorrhoid insertion, and the near-infrared sensing system 3 is used for identifying the trend of the artery through the inner lumen 5 inserted into the anorectum of the patient.

The specific principle of the near-infrared sensing system 3 is as follows: the camera at the orifice of the inner cavity tube 5 and the main light source face an imaging part, because hemoglobin has strong infrared light absorption capacity, and oxyhemoglobin and deoxyhemoglobin have strong near infrared light absorption capacity relative to other tissues, the main light source is a near infrared LED lamp with the wavelength of 760nm, and near infrared rays emitted by the main light source can be absorbed by hemoglobin in arterial blood vessels, so that the reflected light intensity is reduced, reflected light of the main light source is collected by the camera and displayed in an image processed by display equipment, the brightness of the blood vessels is darker, and the thickness, the shape and the layout of the arterial blood vessels can be accurately distinguished. Through the processing of the display, the medical staff can distinguish the artery and vein blood of the punctured area.

LED cold light source illumination, camera and display screen can develop, record a video, make things convenient for the operator to observe the focus condition to make accurate action, reduce the maloperation, promote operation efficiency.

This scheme relies on position sensor development focus tissue artery, can pinpoint the haemorrhoids position, negative pressure mechanism produces the negative pressure, control ligation subassembly is inhaled after aiming at haemorrhoids, utilize length sensor's detection, can detect the length of inhaling haemorrhoids, length sensor is with signal transmission to controller, the controller supplies the art person with length information transmission to the display to observe, control ligation subassembly is automatic overlaps elastic coil 4 on haemorrhoids, afterwards tightens up elastic coil 4 and cuts off elastic wire 17 and can accomplish the ligation. According to the detection of the position sensor, the detection result is displayed on the display screen, and the image can be developed to facilitate observation of an operator.

On the basis of the above embodiment, as further preferred, including being used for letting out the pressure release subassembly of ligation subassembly internal pressure, the pressure release subassembly includes pressure release key, pressure release mouth, pressure release spring, the pressure release mouth communicate in with the pipeline of ligation subassembly intercommunication, the pressure release key set up in on the pressure release mouth, the spring is used for the top in the inside of pressure release key, so that the pressure release key is the pressure release when pushing down, the pressure release key with the pressure release mouth set up in on the handle 16. When the negative pressure device works, the maximum pressure generated by the negative pressure device is smaller than the force of the spring against the pressure relief key, so that the air leakage of the air leakage opening when the negative pressure device works is prevented. When pressure relief is needed, the pressure relief key is pressed down to open the air relief opening, and then pressure relief can be carried out. The pressure relief device is arranged, so that the subsequent hemorrhoids can be conveniently inhaled, and the operation process is simple and quick.

In addition to the above embodiments, it is further preferable that a seal ring is provided between the pressure release key and the pressure release port. The sealing ring is arranged to ensure the sealing performance between the pressure relief key and the pressure relief port, so that the external air is prevented from entering an internal pipeline through the pressure relief port when the negative pressure mechanism works, and the stability of the negative pressure in the ligation component is ensured.

On the basis of the above embodiment, as a further preferable option, the length sensor is an infrared sensor, a mounting tube is coaxially arranged in the center of the ligation assembly, and the infrared sensor is mounted at the front end of the mounting tube.

It should be noted that the infrared sensor is a sensor that uses infrared as a medium to complete a measurement function, and the infrared is also called infrared light, and has properties of reflection, refraction, scattering, interference, absorption, and the like, and the infrared sensor does not contact with a measured object during measurement, and has no friction, and has the advantages of high sensitivity, fast response, and the like. The length of the front end of the hemorrhoid suction ligation component can be calculated by utilizing the phase displacement generated by the back and forth of the high-frequency modulated infrared ray on the distance to be measured. The infrared sensor mainly comprises an infrared detector, an infrared receiver, a radiation modulator, a signal processing system and the like. In order to facilitate replacement, the infrared sensor is connected with a fixed contact arranged on the ligation component through a movable contact, so that the infrared sensor is convenient to disassemble, assemble and replace.

And the time Deltat of the outgoing beam degree is increased, so that the length D is obtained according to the D ═ C Deltat/2, wherein the length D represents the beam speed. The infrared detector is not limited by the interference of other light sources and the use environment, has the advantages of reliable work, strong anti-interference capability, high response speed, long service life and the like, and although infrared rays are invisible light, the emission frequency of the infrared detector is about 38kHz generally and the detection distance is shorter generally, so that the infrared detector is suitable for the design because the physical properties of linear propagation, reflection, refraction and the like of the infrared rays are similar to those of visible light.

The rear end of installation pipe is connected with the ligation subassembly, and the front end is equipped with the preset distance with the front end of ligation subassembly, and infrared sensor can guarantee the stability of infrared sensor installation through the installation of installation pipe, and owing to installation pipe and the coaxial setting of ligation subassembly, can guarantee infrared sensor measuring accuracy.

On the basis of the above embodiment, as a further preferred option, the ligation component comprises an inner lumen 5, a pushing sleeve 6 and a driving mechanism 7, the pushing sleeve 6 is movably sleeved on the periphery of the inner lumen 5, the driving mechanism 7 is arranged in the handle 16, the driving mechanism 7 can push the pushing sleeve 6 along the axial direction of the pushing sleeve 6, and the driving mechanism 7 is in signal connection with the controller.

It should be noted that the pushing sleeve 6 is sleeved on the inner cavity tube 5 and the pushing sleeve 6 can displace relative to the inner gun tube; in addition, the ends of the inner cavity tube 5 and the pushing sleeve 6 close to the hemorrhoids are front ends, the driving mechanism 7 drives the pushing sleeve 6 to slide towards the front end, the elastic coil 4 wound at the front end of the inner cavity tube 5 is pushed onto the hemorrhoids, and the elastic thread 17 is tightened by the take-up mechanism 2, so that the ligation of the hemorrhoids is realized. When the pushing sleeve 6 pushes the elastic coil 4 to be sleeved on the hemorrhoid, the controller controls the wire winding mechanism 2 to synchronously tighten the elastic coil 4, so that the operation efficiency is improved, and the operation is more intelligent.

Before ligation, one end of the elastic line 17 is looped to form an elastic coil 4 and is sleeved at the front end of the inner cavity tube 5, one ends of the inner cavity tube 5 and the pushing sleeve 6 close to the hemorrhoidal tissues are front ends, and the pushing sleeve 6 is pushed by the driving mechanism 7 in the handle 16 to slide towards the front end of the inner cavity tube 5 so as to push the elastic line 17 out and be sleeved on the aligned hemorrhoidal tissues. Preferably, the driving mechanism 7 is an electric push rod, and the electric push rod is in signal connection with the controller.

The ligation assembly adopted by the embodiment can automatically complete ligation according to the control signal of the controller, and is convenient and fast.

On the basis of the above embodiment, as a further preferred, the device comprises a take-up mechanism 2 for tightening the elastic coil 4, wherein the take-up mechanism 2 is arranged on the ligation component, and the take-up mechanism 2 is in signal connection with the controller.

The take-up mechanism 2 comprises a take-up wheel for winding elastic wires 17, a first gear is coaxially arranged on the take-up wheel, a driving motor 19 is arranged in the handle 16, a second gear 18 meshed with the first gear is mounted on an output shaft of the driving motor 19, the front end of the elastic wires 17 is connected with the elastic coils 4, the take-up wheel is rotatably arranged on the handle 16, and the driving motor 19 is in signal connection with the controller.

It should be noted that, the circumference side of tight line wheel is provided with the annular groove to hold elastic line 17, for better fixed elastic line 17, the bottom of annular groove is provided with the mounting hole, in order to fix elastic line 17 on tight line wheel, and rotate along with tight line wheel.

The tightening wheel and the first gear are integrally arranged, one end of the elastic wire 17 is connected with the tightening wheel, the other end of the elastic wire 17 is wound at the front end of the ligation mechanism and is knotted to form the elastic coil 4, the elastic coil 4 formed by the elastic wire 17 is ligated on the haemorrhoid through the action of the ligation mechanism, and the tightening wheel is driven to rotate through the driving motor 19 to tighten the elastic wire 17 so as to tighten the haemorrhoid by the elastic wire 17; the driving motor 19 is connected to the controller through a current sensor, and the controller controls the start and stop of the driving motor 19 according to the received current signal to ensure the tensioning degree, it should be noted that when the elastic wire 17 is tightened, the current of the driving motor 19 changes correspondingly. The elastic coil 4 is tightened through gear transmission, and reliability is high.

In addition to the above-described embodiments, it is further preferable that the wire winding mechanism 2 includes a cutting mechanism 1 for cutting the connection between the elastic thread 4 and the elastic thread 17 wound around the wire winding mechanism 2 after the wire winding mechanism 2 is tightened, and the cutting mechanism 1 is provided outside the handle 16.

Shearing mechanism 1 is including setting up the actuating lever 8 on handle 16 that can follow the activity of ligation mechanism length direction, the front end fixedly connected with of actuating lever 8 and the catch bar 20 that sets up along 8 length direction of actuating lever, the front end of catch bar 20 is equipped with the shearing part, the front end of elastic line 17 passes the shearing part and connects in elastic coil 4, be equipped with the driver that is used for driving 8 forward motion of actuating lever on the handle 16, when 8 forward motion of actuating lever, the front end of elastic line 17 is cuted to the shearing part, in order to cut off elastic coil 4 and elastic line 17 be connected.

It should be noted that the shearing mechanism 1 includes a shearing portion disposed at the ligation end of the ligation stapler, the elastic thread 17 connected to the elastic coil 4 passes through the shearing portion to be connected to the thread take-up mechanism 2 of the ligation stapler, the thread take-up mechanism 2 is used for tightening the elastic thread 17, the shearing portion is connected to the driving push rod 20 and the driving rod 8, and the push rod 20 and the driving rod 8 are used for driving the shearing portion to act to shear the elastic thread 17. The driver is started, the driver drives the driving rod 8 to move towards the front end, and the driving rod 8 synchronously drives the push rod 20 to move towards the front end so as to drive the shearing part to act. Preferably, the actuator is a trigger 9 hinged to a handle 16, one end of the trigger 9 being exposed from the handle 16 and the other end engaging the rear end of the drive rod 8. The trigger 9 is pulled to make the trigger 9 drive the driving rod 8 to move to the front end.

This embodiment simple structure, the processing of being convenient for, installation and operation can be realized cutting off to the elastic line 17 in the anus intestines outside the anus intestines through the transmission of driver.

On the basis of the above embodiment, as a further preferred, the cutting portion includes two blades 12 with their rear ends hinged to each other, the front cutting edges of the two blades 12 are opposite and face the elastic thread 17, the blades 12 are disposed in the strip-shaped sleeve 11, the front end of the strip-shaped sleeve 11 is provided with a threading hole 10, and the front end of the elastic thread 17 passes through the threading hole 10 and is connected to the elastic coil 4.

It should be noted that, two blades 12 are hinged on the outer side wall of the ligation mechanism and located at the front end of the ligation mechanism, the cutting edge of the blade 12 faces the elastic line 17, and the two blades 12 are driven to rotate relatively by a driver to cut the elastic line 17 passing between the two blades 12, so as to realize cutting.

Push rod and bar sleeve 11 extend along the length direction of catch bar 20, catch bar 20 alternates in bar sleeve 11, and catch bar 20 slides in bar sleeve 11, and two blades 12 articulate in bar sleeve 11 through the round pin axle, slide in order promoting two blades 12 to the front end of bar sleeve 11 through actuating lever 8 promotion catch bar 20 and rotate the realization shearing, and the front end of actuating lever 8 alternates in sleeve 11, and is sliding fit.

The front end of the strip-shaped sleeve 11 is provided with a threading hole 10 penetrating through the strip-shaped sleeve 11, and an elastic thread 17 penetrates through the threading hole 10 and is wound at the front end of the ligation mechanism to form an elastic coil 4.

The structure of the embodiment is simple, the two blades 12 are arranged in the strip-shaped sleeve 11, the blades 12 can be prevented from scratching tissues, the two blades 12 are arranged to shear the elastic line 17, the elastic line 17 can be sheared more cleanly, and the cost is lower.

On the basis of the above embodiment, as a further preferred, the pushing rod 20 is provided with a strip-shaped sliding groove 14 which is consistent with the length direction of the pushing rod 20, a cross rod 15 is movably arranged in the strip-shaped sliding groove 14, and two ends of the cross rod 15 are connected to the inner wall of the strip-shaped sleeve 11.

It should be noted that, the quantity of spout can set up to one or more, when setting up to a plurality ofly, sets up a plurality of spouts along catch bar 20's length direction, and equal mobilizable horizontal pole 15 that is equipped with in every spout, the both ends of horizontal pole 15 respectively with the inner wall connection of sleeve 11, horizontal pole 15 and spout sliding fit, horizontal pole 15 can support catch bar 20, horizontal pole 15 can stably restrict the motion of catch bar 20 in bar spout 14, and prevent to drop.

On the basis of the above embodiment, as a further preferred, the blade resetting device includes a resetting mechanism for resetting the blade 12, the resetting mechanism includes two elastic pieces 13 having elasticity, and the two elastic pieces 13 are respectively disposed between the rear ends of the blade backs of the two blades 12 and the strip-shaped sleeve 11.

It should be noted that the reset mechanism is used for driving the two blades 12 after the cutting is completed to reset, and the two blades 12 can be continuously used for the next cutting after the first hemorrhoid is bound. The back of a knife blade of two blades 12 is contradicted with the inner wall of sleeve 11 through two shell fragments 13 respectively, specifically, during the cutting, shell fragment 13 is compressed, and after the cutting was accomplished, shell fragment 13 resumes elastic deformation, and the cutting edge that drives two blades 12 keeps away from mutually, this embodiment simple structure, the installation of being convenient for.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The ligation device with high ligation precision provided by the utility model is introduced in detail. The principles and embodiments of the present invention have been explained herein using specific examples, and the above descriptions of the embodiments are only used to help understand the method and its core ideas of the present invention. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, the present invention can be further modified and modified, and such modifications and modifications also fall within the protection scope of the appended claims.

Claims

1. The utility model provides a ligation device of high ligation precision which characterized in that includes: the hemorrhoid treatment device comprises a handle (16), a controller, a display, a ligation component, a negative pressure mechanism, a position sensor and a length sensor, wherein the ligation component is used for sucking hemorrhoids and sleeving an elastic coil (4) with an adjustable inner diameter on the hemorrhoids;

the ligation component is detachably arranged on the handle (16), the controller and the negative pressure mechanism are both arranged in the handle (16), the display is arranged outside the handle (16), and the position sensor and the length sensor are both arranged in the front end of the ligation component;

2. The ligation device with high ligation precision according to claim 1, wherein the device comprises a pressure relief assembly for releasing pressure in the ligation assembly, the pressure relief assembly comprises a pressure relief key, a pressure relief opening and a pressure relief spring, the pressure relief opening is communicated with a pipeline communicated with the ligation assembly, the pressure relief key is arranged on the pressure relief opening, the spring is used for abutting against the inside of the pressure relief key so as to release pressure when the pressure relief key is pressed down, and the pressure relief key and the pressure relief opening are arranged on the handle (16).

3. The ligation device according to claim 2, wherein a sealing ring is provided between the pressure release key and the pressure release opening.

4. The ligation device according to claim 1, wherein the length sensor is an infrared sensor, the ligation assembly is coaxially provided with a mounting tube at the center, and the infrared sensor is mounted at the front end of the mounting tube.