CN116767960A

CN116767960A - Tension adjusting equipment for high-strength suture line production

Info

Publication number: CN116767960A
Application number: CN202311023371.7A
Authority: CN
Inventors: 李德明; 周玉林
Original assignee: Nantong Chenqiao Zipper Garment Accessories Factory
Current assignee: Nantong Chenqiao Zipper Garment Accessories Factory
Priority date: 2023-08-15
Filing date: 2023-08-15
Publication date: 2023-09-19

Abstract

The application discloses tension adjusting equipment for high-strength suture production, which comprises a tension sensor, a supporting component and a tension adjusting component, wherein the tension sensor is used for sensing tension change of a wire rod, the supporting component comprises a bottom fixing plate and a guide supporting plate arranged on the bottom fixing plate, the tension sensor is arranged at one end of the bottom fixing plate, which is positioned on the guide supporting plate, the guide supporting plate is provided with a guide wheel, and the tension adjusting component comprises a tension wheel, and the tension wheel is matched with the guide wheel on the guide supporting plate and is used for adjusting tension. The application solves the problem that in the prior art, in tension adjustment, the tension wheel adjusts the tension of the suture by tightening or loosening the suture, and particularly, when the tightening or loosening degree is large, the tension wheel only acts on a fixed position. For example, if the tension pulley moves up and down, the thread may be easily broken or pulled off the pulley when the tension is adjusted.

Description

Tension adjusting equipment for high-strength suture line production

Technical Field

The application relates to the technical field of suture production, in particular to tension adjusting equipment for high-strength suture production.

Background

The high-strength suture is a sewing thread with high strength and good wear resistance, and is generally used in industrial sewing and textile industries. Tension control is needed to be carried out on the wire rod in the production process of the high-strength suture line so as to ensure the quality of the wire rod and the sewing effect. To achieve this goal, a tensioning device may be used, which is typically composed of the following parts, tension sensors, for high-strength suture production: the controller is used for sensing tension change of the wire rod and converting the tension change into an electric signal to be output: and receiving signals of the force sensor, and controlling the motor or the air cylinder to move according to the set tension value so as to realize automatic adjustment of the tension of the wire rod.

The tension wheel adjusts the tension of the suture by tightening or loosening the suture, especially when the tightening or loosening is large, only to a fixed position. For example, if the tension pulley moves up and down, the thread may be easily broken or pulled off the pulley when the tension is adjusted.

Disclosure of Invention

This section is intended to outline some aspects of embodiments of the application and to briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section as well as in the description of the application and in the title of the application, which may not be used to limit the scope of the application.

In order to solve the problem that in the prior art, in tension adjustment, the tension wheel adjusts the tension of the suture by tightening or loosening the suture, and particularly when the tightening or loosening degree is large, the tension wheel only acts on a fixed position. For example, if the tension wheel moves up and down, the problems of thread breakage or thread removal and the like are easily caused when the tension is adjusted, and the application provides the following technical scheme:

a tension adjusting device for high-strength suture production comprises a tension sensor for sensing tension change of a wire;

the support assembly comprises a bottom fixing plate and a guide supporting plate arranged on the bottom fixing plate, the tension sensor is arranged at one end of the bottom fixing plate, which is positioned on the guide supporting plate, and a guide wheel is arranged on the guide supporting plate;

the tension adjusting assembly comprises a tension wheel, and the tension wheel is matched with a guide wheel on the guide supporting plate and used for adjusting the tension.

On the basis of the technical scheme, the application can be improved as follows.

As a preferable scheme of the tension adjusting device for high-strength suture production, the application comprises the following steps: the tension sensor is positioned at the front end of the suture line in the transmission direction, and the guide supporting plate is positioned at the rear end of the suture line in the transmission direction.

As a preferable scheme of the tension adjusting device for high-strength suture production, the application comprises the following steps: the number of the guide wheels is two, and the guide wheels are symmetrically arranged at two ends of the guide supporting plate.

As a preferable scheme of the tension adjusting device for high-strength suture production, the application comprises the following steps: the tension adjusting assembly further comprises a bottom fixing plate, a guide supporting plate and a guide wheel;

the tension adjusting device comprises a tension adjusting assembly, a miniature electromagnetic valve, a damping block, a limiting block, a strong magnetic block, a driving arm, a shaft rod, a supporting bearing and a transmission arm.

As a preferable scheme of the tension adjusting device for high-strength suture production, the application comprises the following steps: the back of direction backup pad is provided with miniature solenoid valve, miniature solenoid valve is connected with tension sensor electricity.

As a preferable scheme of the tension adjusting device for high-strength suture production, the application comprises the following steps: the limiting block is arranged on the back of the guide supporting plate, and a damping block for buffering is arranged between the limiting block and the miniature electromagnetic valve.

As a preferable scheme of the tension adjusting device for high-strength suture production, the application comprises the following steps: the limiting block is provided with an arc-shaped chute, the bottom of the driving arm is provided with a strong magnetic block, the strong magnetic block is provided with an arc polishing surface, and the strong magnetic block is matched with the arc-shaped chute of the limiting block in a sliding manner.

As a preferable scheme of the tension adjusting device for high-strength suture production, the application comprises the following steps: the top of the driving arm is connected with one end of a shaft rod, the shaft rod is arranged on the guide supporting plate through a supporting bearing, the other end of the shaft rod is connected with one end of a transmission arm, a tension wheel is arranged at the other end of the transmission arm, and the tension wheel moves in an arc shape through the transmission arm on the shaft rod.

The beneficial effects of the application are as follows: the miniature electromagnetic valve is electrically connected with the tension sensor, so that signals of the force sensor can be received and converted into electric signals to be output. The magnetic force of the miniature electromagnetic valve can be changed by changing the current of the miniature electromagnetic valve, so that the miniature electromagnetic valve is repulsed from the strong magnetic block in the same polarity, and the driving arm is driven to rotate. This allows the tension pulley on the drive arm to move in an arc and squeeze or release the suture on the guide wheel. Because the tension wheel can rotate, the pressure to the suture is more balanced, and the suture is more stable in the transmission process. In this way, a more balanced and safer effect of tension adjustment of the suture can be achieved.

The beneficial effects of the application are as follows: the tension wheel is driven by using an electromagnetic force repulsive mode, so that the response time of the tension wheel can be greatly shortened, and the strength of the wound suture is prevented from being influenced. In addition, if tension fluctuations exist during suture transport, electromagnetic forces repel each other to help regulate the damping buffer, protecting the suture. Thus, this approach provides better suture protection.

The beneficial effects of the application are as follows: the tension adjusting components are symmetrically arranged, so that the action effect of the tension adjusting components is doubled, the tension adjusting effect of the suture is exponentially increased, and the suture is more balanced and safer. In addition, the tension wheel is driven by a shorter distance, so that the suture can be better protected, the response time is shorter, the requirements of actual production are met, and the effects of the strength of the wound suture and the like can be maintained.

The beneficial effects of the application are as follows: the tension roller of the transmission arm is driven to deflect by the shaft rod so as to tightly contact the tension of the suture along with the tension roller pulling the suture more tightly, the purpose of tension adjustment is achieved, sometimes, because factors such as thickness and quality of the suture are different, the transmission arm swings to enable the tension roller to be adjusted too large, the suture is broken, if the driving force of the transmission arm is too large, the lug can be separated from the damping groove to the inner clamping of the next damping groove, at the moment, the tension roller on the transmission arm stops swinging, and therefore the transmission of the suture in the range of the maximum bearing tension is maintained, and the broken wire is avoided.

Second, the second step; through the torque spring, the lug can reset to the inside of initial damping recess to let whole tension adjusting device, resume original tension adjustment's ability, if the tension of suture reduces suddenly simultaneously, through lug and damping recess joint, the cooperation between the torque spring, the tension pulley can be slow resumes at transmission suture in-process, thereby the en can play and avoid the suture to break away from the tension pulley even by the circumstances of breaking.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art. Wherein:

fig. 1 is a perspective view of the whole of the present embodiment.

Fig. 2 is a perspective view of the support assembly of the present embodiment.

Fig. 3 is a perspective view of the support assembly of the present embodiment.

Fig. 4 is a perspective view of the tension adjusting assembly of the present embodiment.

Fig. 5 is an enlarged partial sectional view of fig. 4 of the present embodiment.

Fig. 6 is a perspective view of the tension adjusting assembly of the present embodiment.

Fig. 7 is a schematic diagram of the suture tensioning process of this embodiment.

Fig. 8 is an internal structural view of the shaft of the present embodiment.

Fig. 9 is a partial schematic diagram of fig. 8 according to the present embodiment.

In the figure; a tension sensor 100;

a support assembly 200, a bottom fixing plate 201, a guide support plate 202, and a guide wheel 203;

the tension adjusting assembly 300, the miniature electromagnetic valve 301, the damping block 302, the limiting block 303, the arc chute 303a, the strong magnetic block 304, the arc polishing surface 304a, the driving arm 305, the shaft rod 306, the supporting bearing sleeve 306b, the torsion bar 306c, the damping ring 306d, the damping groove 306d-1, the safety piece 306e, the bump 306e-1, the baffle ring 306e-1a, the return spring 306e-2, the connecting sleeve block 306e-3, the auxiliary rod 306f, the torsion spring 306g, the supporting bearing 306a, the transmission arm 307, the cross connecting rod 307a and the tension pulley 308.

Description of the embodiments

In order that the above-recited objects, features and advantages of the present application will become more readily apparent, a more particular description of the application will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, but the present application may be practiced in other ways other than those described herein, and persons skilled in the art will readily appreciate that the present application is not limited to the specific embodiments disclosed below.

Further, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic can be included in at least one implementation of the application. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

Examples

Referring to fig. 1 to 9, for an embodiment of the present application, which provides a tension adjusting apparatus for high-strength suture production, a tension sensor 100 for monitoring tension variation of a suture, and a support assembly 200 including a bottom fixing plate 201 and a guide support plate 202 above the bottom fixing plate 201. The tension sensor 100 is provided at one end of the bottom fixing plate 201, and a guide wheel 203 is provided on the guide support plate 202. The tension adjustment assembly 300 includes a tension pulley 308 that mates with the guide pulley 203 on the guide support plate 202 for precise adjustment of the tension of the suture;

as shown in fig. 1-3, by electrically connecting the micro solenoid 301 to the tension sensor 100, the signal from the force sensor can be received and converted into an electrical signal for output. The magnitude of the magnetic force of the miniature electromagnetic valve 301 can be changed by changing the magnitude of the current, so that the miniature electromagnetic valve is repulsed with the strong magnetic block 304 in the same polarity, and the driving arm 305 is driven to rotate. This allows the tension pulley 308 on the drive arm 307 to move in an arc and squeeze or release the suture on the guide wheel 203. Because the tension pulley 308 can rotate, the pressure on the suture is more balanced and the suture is more stable during transport. In this way, a more balanced and safer effect of tension adjustment of the suture can be achieved.

Further, in actual production, the effect of tension adjustment of the suture that is more balanced and safer can significantly improve the quality and efficiency of the suture, and reduce the incidence of suture breakage and other failures. Meanwhile, the automatic adjusting system using the miniature electromagnetic valve and the tension sensor can greatly improve production and reduce the error rate of manual operation. In addition, the quality and the appearance of the sewn product are also improved remarkably.

The tension sensor 100 is positioned at the forward end of the suture transport direction, while the guide support plate 202 is positioned at the rearward end of the suture transport direction. The guide support plate 202 is provided with two guide wheels 203 symmetrically disposed at both ends of the guide support plate 202. The design can effectively support the suture and ensure the accuracy of the transmission direction of the suture;

as shown in fig. 3-5, driving the tension pulley 308 with electromagnetic force in a repulsive manner can greatly shorten the response time and avoid the influence of the strength after the suture is wound. In addition, if tension fluctuations exist during suture transport, electromagnetic forces repel each other to help regulate the damping buffer, protecting the suture. Thus, this approach provides better suture protection.

Further, the use of the electromagnetic force to repel the tension pulley 308 also reduces maintenance and service costs of the machine, resulting in a longer service life of the machine.

The tension adjusting assembly 300 further includes a bottom fixing plate 201, a guide support plate 202, a micro solenoid valve 301, a damping block 302, a stopper 303, a ferromagnetic block 304, a driving arm 305, a shaft 306, a support bearing 306a, and a transmission arm 307. The back of the guide support plate is provided with a micro solenoid valve 301 electrically connected to the tension sensor 100. The stopper 303 is provided at the rear surface of the guide support plate 202, and the damping block 302 is placed between the stopper 303 and the micro solenoid valve 301 to cushion the impact. The arc chute 303a is arranged on the limiting block 303, and the bottom of the strong magnetic block 304 is provided with an arc polished surface 304a and is arranged in the arc chute 303a of the limiting block 303 in a sliding manner. The bottom of the driving arm 305 is connected to the ferromagnetic block 304, while the top is connected to one end of the shaft 306. The shaft 306 is disposed on the guide support plate 202 through a support bearing 306 a. The other end of the shaft 306 is connected to one end of the arm 307, and the other end of the arm 307 is provided with a tension pulley 308. The tension wheel 308 moves in an arc shape through the shaft rod 306 and the transmission arm 307 to adjust the tension of the suture;

as shown in fig. 5-6, the tension adjusting assembly 300 can be symmetrically arranged to double the action effect, so that the tension adjusting effect of the suture is exponentially increased, and the suture is more balanced and safer. In addition, the tension wheel 308 is driven to a shorter distance, so that the suture can be better protected, the response time is shorter, the effect of winding strength and the like of the suture can be kept, as shown in fig. 7, the suture rolls on the tension wheel 308 and the tension wheel 308 moves in an arc shape, and the suture can be uniformly stressed and stably transported when being pressed no matter whether the suture is static or moving;

further, by symmetrically positioning the tension adjustment assemblies 300, a more uniform tension is generated by the tension pulley 308 during the suture transport process, thereby improving the stability of the winding quality. In addition, since the tension adjusting assembly 300 doubles the effect, the suture can be better protected, the occurrence of the problems such as suture breakage and the like can be reduced, and the production efficiency and the product quality can be improved. Therefore, by symmetrically arranging the tension adjusting assemblies 300, the action and effect of driving the tension pulley 308 in the electromagnetic force repulsive manner can be exerted to the greatest extent, the stitching quality and the production efficiency are improved, and besides symmetrically arranging the tension adjusting assemblies 300, the control and the monitoring of the tension adjusting assemblies 300 can be enhanced to adapt to different production requirements. Advanced sensing technology can be adopted to monitor tension fluctuation of the suture in real time, respond quickly and adjust corresponding parameters of the tension wheel 308, so that the production process is more stable. In addition, parameters of the tension adjusting assembly 300 may be set differently for different production materials and production processes to achieve optimal sewing effect.

As shown in fig. 8-9, the shaft 306 drives the actuator arm 307, deflecting the tension pulley 308 to adjust the tension of the suture. However, due to the varying thickness and quality of the suture, there are times when the swing range of the actuator arm 307 is too large, resulting in an over-adjustment of the tension pulley 308, thereby breaking the suture. If the driving force of the driving arm 307 is too large, the bump 306e-1 will separate from the current damping groove 306d-1 and snap into the next internal groove 306d-1, so that the tension pulley 308 stops swinging, ensuring that the suture is always transported within the maximum bearing tension range, avoiding broken threads,

further, 1. Reduce the risk of suture breakage: by reducing the driving force of the driving arm 307, the occurrence of the protrusion 306e-1 coming out of the damping groove 306d-1 can be avoided, thereby reducing the possibility of the suture breaking. Secondly, stability of the suture is improved: by properly adjusting the driving force of the driving arm 307, the tension pulley 308 can be kept at proper tension, so that the stability of the suture in the process of transmission is ensured, and the uneven tightness is reduced. Thirdly, the durability of the suture is improved: by reasonably controlling the driving force of the driving arm 307, the tension wheel 308 can work in a normal range, so that damage to the suture caused by excessive tension is avoided, and the service life of the suture is prolonged;

further, the bump 306e-1 can be returned to the inside of the original damping groove 306d-1 by the torsion spring 306g, so that the whole tension adjusting device can restore the original tension adjusting function. Meanwhile, when the tension of the suture is suddenly reduced, the cooperation between the protruding block 306e-1 and the damping groove 306d-1 and the action of the torque spring 306g can enable the tension wheel 308 to slowly recover in the suture transmission process, so that the situation that the suture is separated from the tension wheel 308 and even broken is avoided, and the suture has the following advantages that the stability of the suture is improved: the torque spring 306g allows the entire tension adjustment device to return to its original adjusted state, allowing the tension pulley 308 to adjust the tension of the suture steadily, ensuring that the suture remains stable during delivery. Secondly, avoiding suture fracture: by the cooperation of the bump 306e-1 and the damping groove 306d-1 and the action of the torsion spring 306g, when the tension of the suture is suddenly reduced, the tension pulley 308 can slowly restore the tension, so that the situation that the suture is separated from the tension pulley and even is broken is avoided, and the integrity of the suture is ensured. Thirdly, improving production efficiency: under the condition of avoiding suture fracture, the production process can be more stable and continuous, and frequent shutdown maintenance or suture replacement is not needed, so that the production efficiency is improved.

The working principle is as follows; the guide wheels 203 on the guide support plate 202 cooperate to adjust the tension of the suture. After passing the guide wheel 203 and the tension wheel 308 from the tension sensor 100, tension adjustment of the suture can be achieved so that tension of the suture is maintained within a proper range, thereby ensuring quality and stability of the suture. After the suture passes through the guide wheel 203 and the tension wheel 308, the transmission arm 307 moves in an arc shape under the action of the shaft lever 306, and the strong magnetic block 304 on the driving arm 305 also slides along with the movement of the transmission arm 307, so as to control the switch of the miniature electromagnetic valve 301, and realize real-time monitoring and adjustment of the suture tension. The whole tension adjusting assembly 300 can monitor the tension change of the suture in real time and adjust the tension in real time through the miniature electromagnetic valve 301, thereby realizing accurate control of the suture and ensuring the quality of the suture.

It is important to note that the construction and arrangement of the application as shown in the various exemplary embodiments is illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters (e.g., temperature, pressure, etc.), mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described in this application. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are intended to be included within the scope of present application. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. In the claims, any means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present applications. Therefore, the application is not limited to the specific embodiments, but extends to various modifications that nevertheless fall within the scope of the appended claims.

Furthermore, in order to provide a concise description of the exemplary embodiments, all features of an actual implementation may not be described (i.e., those not associated with the best mode presently contemplated for carrying out the application, or those not associated with practicing the application).

It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

It should be noted that the above embodiments are only for illustrating the technical solution of the present application and not for limiting the same, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present application may be modified or substituted without departing from the spirit and scope of the technical solution of the present application, which is intended to be covered in the scope of the claims of the present application.

Claims

1. A tension adjusting device for high-strength suture production is characterized in that: comprising the steps of (a) a step of,

a tension sensor (100), the tension sensor (100) being configured to sense a tension change of the wire;

the support assembly (200) comprises a bottom fixing plate (201) and a guide supporting plate (202) arranged on the bottom fixing plate (201), the tension sensor (100) is arranged at one end of the bottom fixing plate (201) positioned on the guide supporting plate (202), and a guide wheel (203) is arranged on the guide supporting plate (202);

the tension adjusting assembly (300) comprises a tension pulley (308), and the tension pulley (308) is matched with a guide pulley (203) on the guide supporting plate (202) for adjusting the tension.

2. The tensioning device for high strength suture production of claim 1, wherein: the tension sensor (100) is positioned at the front end of the suture conduction direction, and the guide support plate (202) is positioned at the rear end of the suture conduction direction.

3. The tensioning device for high strength suture production of claim 1, wherein: the number of the guide wheels (203) is two, and the guide wheels (203) are symmetrically arranged at two ends of the guide supporting plate (202).

4. The tensioning device for high strength suture production of claim 1, wherein: the tension adjusting assembly (300) further comprises a bottom fixing plate (201), a guide supporting plate (202) and a guide wheel (203);

the tension adjusting device comprises a tension adjusting assembly (300), a miniature electromagnetic valve (301), a damping block (302), a limiting block (303), a strong magnetic block (304), a driving arm (305), a shaft lever (306), a supporting bearing (306 a) and a transmission arm (307).

5. The tensioning device for high strength suture production of claim 4, wherein: the back of the guide supporting plate (202) is provided with a miniature electromagnetic valve (301), and the miniature electromagnetic valve (301) is electrically connected with the tension sensor (100).

6. The tensioning device for high strength suture production of claim 5, wherein: the limiting block (303) is arranged on the back surface of the guide supporting plate (202), and a damping block (302) for buffering is arranged between the limiting block (303) and the miniature electromagnetic valve (301).

7. The tensioning device for high strength suture production of claim 5, wherein: an arc-shaped chute (303 a) is formed in the limiting block (303), a strong magnetic block (304) is arranged at the bottom of the driving arm (305), the strong magnetic block (304) is provided with an arc polishing surface (304 a), and the strong magnetic block (304) is arranged in the arc-shaped chute (303 a) of the limiting block (303) in a matched sliding mode.

8. The tensioning device for high strength suture production of claim 7, wherein: the top of the driving arm (305) is connected with one end of a shaft lever (306), the shaft lever (306) is arranged on the guide supporting plate (202) through a supporting bearing (306 a), the other end of the shaft lever (306) is connected with one end of a transmission arm (307), the other end of the transmission arm (307) is provided with a tension wheel (308), the tension wheel (308) moves in an arc shape through the transmission arm (307) on the shaft lever (306), the transmission arm (307) is fixedly sleeved in a connecting sleeve block (306 e-3) through a cross connecting rod (307 a), the connecting sleeve block (306 e-3) is sleeved in the shaft lever (306) through a supporting bearing sleeve (306 b), one end of the supporting bearing sleeve (306 b) is provided with an auxiliary rod (306 f), a torque spring (306 g) is sleeved on the auxiliary rod (306 f), one end of the torque spring (306 g) is connected with the supporting bearing sleeve (306 b), the other end of the torque spring (306 g) is connected with the inside of the shaft lever (306), the supporting sleeve (306 b) is provided with a damping ring (306 d), the outer surface of the supporting sleeve (306 d) is provided with a damping ring (306 d), the damping ring (306 d) is provided with a damping ring (306 d) and the damping ring (306 d) is provided with a), the damping ring is matched with the damping ring (1), the safety piece (306 e) is fixedly connected with one end of the shaft rod (306), the safety piece (306 e) comprises a protruding block (306 e-1), a baffle ring (306 e-1 a), a reset spring (306 e-2) and a connecting sleeve block (306 e-3), the connecting sleeve block (306 e-3) is fixedly connected with one end of the shaft rod (306), the connecting sleeve block (306 e-3) is sleeved with the protruding block (306 e-1), the protruding block (306 e-1) is sleeved with the reset spring (306 e-2) through the baffle ring (306 e-1 a), and one end of the protruding block (306 e-1) is matched and clamped in a damping groove (306 d-1) of the damping ring (306 d).