CN111957514A

CN111957514A - High-efficient reciprocating type point gum machine constructs

Info

Publication number: CN111957514A
Application number: CN202010829946.4A
Authority: CN
Inventors: 宋尚海; 游常青; 刘军
Original assignee: Maanshan Yingweiai Ecology Technology Co ltd
Current assignee: Maanshan Yingweiai Ecology Technology Co ltd
Priority date: 2020-08-18
Filing date: 2020-08-18
Publication date: 2020-11-20

Abstract

The invention discloses a high-efficiency reciprocating dispensing mechanism which comprises a vertical plate, an air cylinder, a support, a limiting frame, a connecting rod, a rotating shaft, a swinging disc, a square sliding rod, a limiting pin, a limiting head, a guiding and limiting mechanism, a supporting plate, a rubber pad and a vibrating dispensing mechanism. The device simple structure, stretching out and the return stroke homoenergetic of cylinder drive vibration point gum machine structure and vibrate the point and glue, have improved point and have glued efficiency, and the point precision is high, and the glue solution is remained fewly, has very strong practicality.

Description

High-efficient reciprocating type point gum machine constructs

Technical Field

The invention relates to a glue dispensing device, in particular to a high-efficiency reciprocating type glue dispensing mechanism.

Background

The mode is glued to syringe needle formula point has now been generally used for LED lamp plate, all kinds of semi-manufactured goods PCB board production owing to have advantages such as convenient operation, and general process is: the glue dispensing device comprises a glue dispensing barrel, a driving mechanism, a glue dispensing valve, a needle cylinder, a glue pressing valve, a driving mechanism and a glue dispensing valve, wherein the glue dispensing barrel is used for dispensing glue, the driving mechanism drives the needle cylinder with a needle head to move downwards to be close to a glue dispensing area, the glue dispensing valve is opened to press the glue into the needle head by using pressure difference to extrude the glue into the glue dispensing area, after the glue dispensing is completed, the driving mechanism returns to complete single glue dispensing operation, the flowing quantity of the glue is difficult to control accurately when the pressure changes due to poor flowability of the glue, material waste or poor glue pressing is caused, meanwhile, when the driving mechanism (such as an air cylinder/electric push rod) drives the needle. In view of the above drawbacks, it is necessary to design an efficient reciprocating dispensing mechanism.

Disclosure of Invention

The invention aims to provide the efficient reciprocating type glue dispensing mechanism, the stretching and returning of the air cylinder can drive the vibration glue dispensing mechanism to perform vibration glue dispensing, the glue dispensing efficiency is improved, the glue dispensing precision is high, glue solution is less in residue, and the practicability is high.

In order to solve the technical problems, the technical scheme of the invention is as follows: a high-efficiency reciprocating dispensing mechanism comprises a vertical plate, a cylinder, a support, a limiting frame, a connecting rod, a rotating shaft, a swinging disc, a square sliding rod, a limiting pin, a limiting head, a guide limiting mechanism, a supporting plate, a rubber pad and a vibration dispensing mechanism, wherein the cylinder is positioned at the upper end of the vertical plate, the cylinder is connected with the vertical plate through a bolt, the support is positioned at the upper end of the vertical plate, the support is connected with the vertical plate through a bolt, the limiting frame is positioned at the outer side of the support, the limiting frame is connected with the support through a bolt, the connecting rod is positioned at the right side of the cylinder, the connecting rod is connected with a hinge of the cylinder, the rotating shaft penetrates through the connecting rod and penetrates through the limiting frame, the rotating shaft is connected with the connecting rod through a bolt and is rotatably connected with the limiting frame, the swinging disc is positioned at the outer side of the limiting, square slide bar quantity be 2, along spacing frame bilateral symmetry arrangement, the spacer pin be located square slide bar middle part and run through the swing dish, spacer pin and square slide bar interference fit link to each other, spacing first quantity be 2, along the left and right directions symmetrical arrangement of spacing frame, direction stop gear be located the spacing frame outside and be located the square slide bar outside, direction stop gear pass through the bolt with spacing frame and link to each other, the layer board be located square slide bar lower extreme, layer board and square slide bar pass through the bolt and link to each other, the rubber pad be located layer board bottom, rubber pad and layer board bond and link to each other, vibration point gum machine construct and run through rubber pad and layer board, vibration point gum machine construct and pass through the screw thread with the layer board and link to each other.

The invention is further improved as follows:

furthermore, the swing disc is provided with two swing grooves which are symmetrically arranged and arranged.

Furthermore, the shape of the swing groove is an ellipse and penetrates through the main body of the swing disc.

Furthermore, spacing head still be equipped with the crashproof pad, the crashproof pad be located spacing overhead end, the crashproof pad pass through the bolt with spacing head and link to each other.

Further, the axis of the crash pad coincides with the axis of the square sliding rod.

Furthermore, the number of the guide limiting mechanisms is 2, and the guide limiting mechanisms are arranged along the limiting frame in an up-and-down symmetrical mode.

Furthermore, the direction stop gear include the limiting plate, along the elastic guide mechanism of limiting plate symmetrical arrangement, the limiting plate be located the limiting frame outside, limiting plate and limiting frame pass through the bolt and link to each other, elastic guide mechanism run through the limiting plate main part.

Furthermore, the elastic guide mechanism comprises an adjusting screw, a steel ball and a compression spring, the lower end of the adjusting screw extends into the limiting plate, the steel ball penetrates through the limiting plate to be in contact with the square sliding rod, and the compression spring is located between the adjusting screw and the steel ball.

Compared with the prior art, the efficient reciprocating type dispensing mechanism has the advantages that during operation, the air cylinder acts to drive the rotating shaft to rotate through the connecting rod, so that the swing disc is driven to rotate forwards or backwards in a certain range, the limiting pin is inserted into the swing groove, one of the two symmetrically-arranged square sliding rods moves upwards while the other moves downwards, the downwards-moving square sliding rod can drive the vibration dispensing mechanism fixedly connected with the supporting plate to move downwards to perform vibration dispensing with a product to be dispensed, the rubber pad can reduce vibration impact on a moving part during vibration dispensing of the vibration dispensing mechanism, the running stability is improved, the guide limiting mechanism can elastically support the square sliding rod in a floating mode, and the moving stability is improved. The device simple structure, stretching out and the return stroke homoenergetic of cylinder drive vibration point gum machine structure and vibrate the point and glue, have improved point and have glued efficiency, and the point precision is high, and the glue solution is remained fewly, has very strong practicality.

Drawings

FIG. 1 shows a three-dimensional view of the present invention

FIG. 2 is a schematic view of the structure of the guiding and limiting mechanism of the present invention

FIG. 3 is a schematic view of the structure of the vibration dispensing mechanism of the present invention

FIG. 4 is a partial enlarged view of the invention shown in FIG. 3

FIG. 5 is a schematic view showing the structure of the hose of the present invention

FIG. 6 is a schematic view of the swing mechanism of the present invention

In the figure: the vertical plate 1, the cylinder 2, the support 3, the limit frame 4, the connecting rod 5, the rotating shaft 6, the swing disc 7, the square sliding rod 8, the limit pin 9, the limit head 10, the guide limit mechanism 11, the supporting plate 12, the rubber pad 13, the vibration dispensing mechanism 14, the swing groove 701, the anti-collision pad 1001, the limit plate 1101, the elastic guide mechanism 1102, the adjusting screw 1103, the steel ball 1104, the compression spring 1105, the pipe body 1401, the gun head 1402, the seal base 1403 and the rubber delivery pipe 1404, the device comprises a tapered liquid-dividing head 1405, a spring 1406, a ball-type needle 1407, a locking plate 1408, a cylinder 1409, an electric heating tube 1410, a lower insulating pressure seat 1411, a piezoelectric ceramic plate 1412, a driving plate 1413, an insulating nut 1414, a locking nut 1415, a swinging mechanism 1416, a temperature sensor 1417, a tapered sealing head 1418, a straight tube 1419, a glue leakage hole 1420, a main channel 1421, a branch channel 1422, a support 1423, a ball head 1424, a swinging shaft 1425, an inertia block 1426, a swinging plate 1427 and a liquid passing hole 1428.

Detailed Description

As shown in fig. 1 and 2, a high-efficiency reciprocating dispensing mechanism comprises a vertical plate 1, a cylinder 2, a support 3, a limiting frame 4, a connecting rod 5, a rotating shaft 6, a swing disc 7, a square sliding rod 8, a limiting pin 9, a limiting head 10, a guiding limiting mechanism 11, a supporting plate 12, a rubber pad 13 and a vibration dispensing mechanism 14, wherein the cylinder 2 is positioned at the upper end of the vertical plate 1, the cylinder 2 is connected with the vertical plate 1 through a bolt, the support 3 is positioned at the upper end of the vertical plate 1, the support 3 is connected with the vertical plate 1 through a bolt, the limiting frame 4 is positioned at the outer side of the support 3, the limiting frame 4 is connected with the support 3 through a bolt, the connecting rod 5 is positioned at the right side of the cylinder 2, the connecting rod 5 is hinged with the cylinder 2, the rotating shaft 6 penetrates through the connecting rod 5 and penetrates through the limiting frame 4, the rotating shaft 6 is connected with the connecting rod 5 through a bolt and, the swing disc 7 is positioned on the outer side of the limit frame 4 and is penetrated through by the rotating shaft 6, the swing disc 7 is connected with the limit frame 4 in an interference fit manner, the number of the square sliding rods 8 is 2, the square sliding rods are symmetrically arranged along the left and right directions of the limit frame 4, the limit pin 9 is positioned in the middle of the square sliding rods 8 and penetrates through the swing disc 7, the limit pin 9 is connected with the square sliding rods 8 in an interference fit manner, the number of the limit heads 10 is 2, the limit heads are symmetrically arranged along the left and right directions of the limit frame 4, the guide limit mechanism 11 is positioned on the outer side of the limit frame 4 and is positioned on the outer side of the square sliding rods 8, the guide limit mechanism 11 is connected with the limit frame 4 through bolts, the supporting plate 12 is positioned at the lower end of the square sliding rods 8, the supporting plate 12 is connected with the square sliding rods 8 through bolts, the rubber pad 13 is positioned at the bottom of, the vibration dispensing mechanism 14 penetrates through the rubber pad 13 and the supporting plate 12, the vibration dispensing mechanism 14 is connected with the supporting plate 12 through threads, the rubber pad 13 can effectively reduce the influence of vibration on the stroke of the air cylinder 2 when the vibration dispensing mechanism 14 works and improve the operation precision, the swing disc 7 is provided with two swing grooves 701, the swing grooves 701 are symmetrically arranged and connected with the swing disc 7, the swing grooves 701 are oval and penetrate through the main body of the swing disc 7, the limiting head 10 is further provided with the anti-collision pad 1001, the anti-collision pad 1001 is positioned at the upper end of the limiting head 10, the anti-collision pad 1001 is connected with the limiting head 10 through bolts, the anti-collision pad 1001 can effectively buffer when colliding with the square sliding rod 8 in the front direction, the impact force is reduced, the precise vibration dispensing mechanism 14 is protected, the service life of the precise vibration dispensing mechanism 14 is prolonged, the axis of the anti-collision pad 1001 is coincident with the axis of the square sliding rod 8, the number of the guide limiting mechanisms 11 is 2, the guide limiting mechanisms 11 are arranged along the limiting frame 4 in an up-and-down symmetrical manner, each guide limiting mechanism 11 comprises a limiting plate 1101 and elastic guiding mechanisms 1102 arranged along the limiting plate 1101 in a symmetrical manner, the limiting plates 1101 are positioned on the outer side of the limiting frame 4, the limiting plates 1101 are connected with the limiting frame 4 through bolts, the elastic guiding mechanisms 1102 penetrate through the main body of the limiting plates 1101, each elastic guiding mechanism 1102 comprises an adjusting screw 1103, a steel ball 1104 and a compression spring 1105, the lower end of the adjusting screw 1103 extends into the limiting plate 1101, the steel ball 1104 penetrates through the limiting plate 1101 to be contacted with the square sliding rod 8, the compression spring 1105 is positioned between the adjusting screw 1103 and the steel ball 1104, the compression amount of the compression spring 1105 can be adjusted by manually adjusting the position of the adjusting screw 1103, so that the positive pressure of the steel ball 1104 on the square sliding rod 8 is adjusted, and further the friction force generated, the square sliding rod 8 is ensured to run stably without rushing.

As shown in fig. 3, 4, 5 and 6, the vibration dispensing mechanism 14 comprises a tube body 1401, a gun head 1402, a sealing seat 1403, a rubber delivery tube 1404, a tapered liquid-separating head 1405, a spring 1406, a ball-type needle 1407, a locking plate 1408, a tube body 1409, an electric heating tube 1410, a lower insulating pressure seat 1411, a piezoelectric ceramic plate 1412, a driving plate 1413, an insulating nut 1414, a locking nut 1415, a swinging mechanism 1416 and a temperature sensor 1417, wherein the tube body 1401 is connected with a supporting plate 12 through bolts, the gun head 1402 is sleeved at the bottom of the tube body 1401, the sealing seat 1403 is arranged at the upper end inside the tube body 1401, the sealing seat 1403 is connected with the tube body 1401 in a threaded manner, the rubber delivery tube 1404 penetrates through the sealing seat 1403 and the tube body 1401, the tapered liquid-separating head 1405 is arranged at the inner side of the gun head 1402 and at the lower end of the rubber delivery tube 1404, the tapered liquid-separating head 1405 is connected with the rubber delivery tube 1404, the rubber delivery tube 1406 in a, the ball-type needle 1407 penetrates through the gun head 1402 to be connected with the conical liquid separation head 1405, the locking plate 1408 is positioned at the outer side of the tube body 1401, the locking plate 1408 is integrally connected with the tube body 1401, the tube body 1409 is positioned at the outer side of the locking plate 1408 and penetrated through the tube body 1401, the tube body 1409 is connected with the locking plate 1408 through bolts, the electric heating tubes 1410 are not less than 2 in number and are symmetrically arranged at the top of the tube body 1409, the lower insulating pressure seat 1411 is positioned at the outer side of the tube body 1401 and is positioned at the inner side of the tube body 1409, the lower insulating pressure seat 1411 is in threaded connection with the tube body 1401, the piezoelectric ceramic sheet 1412 is stacked at the top of the lower insulating pressure seat 1411 and is positioned at the penetrating through of the tube body 1401, the upper surface and the lower surface of the piezoelectric ceramic sheet 1412 are provided with a layer of insulating layer with uniform thickness, the insulating layer is made of epoxy, the insulating, the insulating nut 1414 is arranged at the upper end of the driving sheet 1413 and sleeved outside the tube body 1401, the locking nut 1415 is arranged at the upper end of the insulating nut 1414 and sleeved outside the tube body 1401, the number of the swing mechanisms 1416 is not less than 3, the swing mechanisms 1416 are uniformly arranged at the bottom of the driving sheet 1413, the temperature sensor 1417 is positioned at the lower end of the tube body 1409, the temperature sensor 1417 is connected with the tube body 1409 through bolts, the inner side of the tube body 1409 is filled with fluid, the fluid is one of electrical insulating oil and non-Newtonian fluid, and as the specific heat capacity of the electrical insulating oil and the non-Newtonian fluid is relatively high and higher heating temperature can be obtained in a low-pressure state, the electrical heating tube 1410 is used for directly heating the fluid, the swing mechanism 1416 is driven by the driving sheet 1413 to stir the fluid, the heat exchange speed is increased, the heating of the glue solution inside the tube body 1401 is realized, the safety performance is improved.

The rubber delivery pipe 1404 comprises a conical sealing head 1418, a straight pipe 1419 and rubber leakage holes 1420, the conical sealing head 1418 is inserted into the inner side of the sealing seat 1403, the outer side surface of the conical sealing head 1418 is attached to the inner side surface of the sealing seat 1403, the straight pipe 1419 is positioned at the bottom of the conical sealing head 1418 and at the top of the conical liquid distribution head 1405, the straight pipe 1419 is integrally connected with the conical sealing head 1418 and is in threaded connection with the conical liquid distribution head 401, the rubber leakage holes 1420 are not less than 2 in number and are uniformly arranged along the vertical direction of the straight pipe 1419, when heating is performed, rubber liquid enters the pipe body 1401 through an opening at the upper end of the pipe body 1401, and the rubber liquid is attached to the inner side surface of the sealing seat 1403 to form sealing due to the fact that the outer side surface of the conical sealing head 1418 is attached to the inner side surface of the sealing seat 1403, the electric heating pipe 1410 heats fluid in the pipe body 1409, the piezoelectric ceramic piece 1412, thereby drive swing mechanism 1416 and stir the fluid, and then heat body 1401, because the vibration effect of piezoceramics piece 1412, the glue solution takes place the vibration, has accelerated the heat exchange process of glue solution and body 1401, has improved heating efficiency and heating frequency, and then has improved the mobility of glue solution, and after temperature sensor 1417 detected and reached the setting temperature, electric heating pipe 1410 stopped the heating.

The conical liquid dividing head 1405 is further provided with a main channel 1421 and branch channels 1422, the main channel 1421 is arranged at the center of the conical liquid dividing head 1405 and communicated with the cavity of the straight pipe 1419, the number of the branch channels 1422 is not less than 2, and the branch channels 1422 are symmetrically arranged along the left and right directions of the conical liquid dividing head 1405, penetrate through the main body of the conical liquid dividing head 1405 and are communicated with the cavity of the main channel 1421.

The swing mechanism 1416 further comprises a support 1423, a ball 1423, a swing shaft 1425, an inertia block 1426, a swing sheet 1427 and a liquid passing hole 1428, the support 1423 is located at the lower end of the driving sheet 1413, the support 1423 is riveted with the driving sheet 1413, the ball 1424 is arranged inside the support 1423, the swing shaft 1425 is located at the lower end of the ball 1424 and penetrates through the support 1423, the swing shaft 1425 is connected with the ball 1424 in an interference fit manner, the inertia block 1426 is located at the bottom of the swing shaft 1425, the inertia block 1426 is connected with the swing shaft 1425 in an interference fit manner, the swing sheets 1427 are evenly arranged in the circumferential direction of the swing shaft 1425 in number of 2, the swing sheet 1427 is further provided with a plurality of liquid passing holes 1428, the liquid passing holes 1428 are evenly arranged in the vertical direction of the swing sheet ball 1427, and the swing sheet 1424 is only subjected to displacement constraint and can freely rotate at least in the inner side of the support 1423, after the oscillating shaft 1425 is installed, the oscillating shaft 1425 can oscillate within a certain range, when the piezoelectric ceramic sheet 1412 is electrified to drive the driving sheet 1413 to vibrate with small amplitude, the inertia block 1426 is excited to drive the oscillating shaft 1425 to oscillate within a certain range, and since the fluid passing hole 1428 can continuously pass through the fluid and the outer area of the oscillating sheet 1427 cannot pass through the fluid, the output speed of the two parts of fluid is different, thereby realizing the flow of the fluid and promoting the heat exchange.

The process of vibration point is as follows: the square sliding rod 8 drives the vibration dispensing mechanism 14 to move downwards, the spherical needle 1407 made of heat-conducting ceramic material is contacted with an LED lamp panel to be dispensed and then lifted, the rubber delivery tube 1404 moves upwards, so that the outer side surface of the conical sealing head 1418 is separated from the inner side surface of the sealing seat 1403, the outer side surface of the conical liquid distribution head 1405 is separated from the inner side surface of the gun head 1402, under the vibration action of the piezoelectric ceramic piece 1412, glue liquid enters the straight tube 1419 through the glue leakage hole 1420 and then continuously passes through the main channel 1421 and the branch channel 1422 and then falls on the part to be dispensed along the surface of the spherical needle 1407, then, the driving mechanism drives the mechanism to move upwards, the spring 1406 resets, so that the outer side surface of the conical sealing head 1418 is attached to the inner side surface of the sealing seat 1403, the outer side surface of the conical liquid distribution head 1405 is attached to the inner side surface of the gun head 1402, so as to realize the quick blocking of, the glue solution at the position to be glued has low temperature and poor fluidity, so that under the action of surface tension and gravity, the residual glue solution at the spherical needle 1407 is less and the glue solution forms flat arc-shaped liquid drops at the position to be glued, when the spherical needle 1407 continuously moves along a product to be processed, a glue solution tape can be uniformly generated, the situations of cut-off and the like of the glue solution tape can not occur, the glue solution tape is suitable for various working condition requirements, and compared with the liquid drops with higher height formed by the traditional glue dispensing needle, the glue solution tape has the advantages of large contact area and glue overflow possibility in the subsequent device bonding.

The working principle is as follows: when the device works, the air cylinder 2 acts to drive the rotating shaft 6 to rotate through the connecting rod 5, so that the swinging disc 7 is driven to rotate forwards or backwards in a certain range, and the limiting pin 9 is inserted into the swinging groove 701, so that when the swinging disc 7 rotates, one of the two symmetrically arranged square sliding rods 8 moves upwards, the other one moves downwards, the downwards-moved square sliding rod 8 can drive the vibration dispensing mechanism 14 fixedly connected with the supporting plate 12 to downwards move to perform vibration dispensing on a product to be dispensed, the rubber pad 13 can reduce vibration impact on a moving part during vibration dispensing of the vibration dispensing mechanism 14, the running stability is improved, the guide limiting mechanism 11 can elastically support the square sliding rod 8 in a floating manner, and the moving stability is improved. The device simple structure, stretching out of cylinder 2 and the equal energy of return stroke drive vibration point gum machine structure 14 and vibrate the point and glue, have improved point and have glued efficiency, and the point precision is high, and the glue solution is remained fewly, has very strong practicality.

The present invention is not limited to the above-described embodiments, and those skilled in the art will be able to make various modifications without creative efforts from the above-described conception, and fall within the scope of the present invention.

Claims

1. A high-efficiency reciprocating dispensing mechanism is characterized by comprising a vertical plate, an air cylinder, a support, a limiting frame, a connecting rod, a rotating shaft, a swinging disc, a square sliding rod, a limiting pin, a limiting head, a guiding limiting mechanism, a supporting plate, a rubber pad and a vibration dispensing mechanism, wherein the air cylinder is arranged at the upper end of the vertical plate, the air cylinder is connected with the vertical plate through a bolt, the support is arranged at the upper end of the vertical plate, the support is connected with the vertical plate through a bolt, the limiting frame is arranged at the outer side of the support, the limiting frame is connected with the support through a bolt, the connecting rod is arranged at the right side of the air cylinder, the connecting rod is connected with an air cylinder hinge, the rotating shaft penetrates through the connecting rod and penetrates through the limiting frame, the rotating shaft is connected with the connecting rod through a bolt and is rotatably connected with the limiting frame, the swinging disc is arranged at the outer side, square slide bar quantity be 2, along spacing frame bilateral symmetry arrangement, the spacer pin be located square slide bar middle part and run through the swing dish, spacer pin and square slide bar interference fit link to each other, spacing first quantity be 2, along the left and right directions symmetrical arrangement of spacing frame, direction stop gear be located the spacing frame outside and be located the square slide bar outside, direction stop gear pass through the bolt with spacing frame and link to each other, the layer board be located square slide bar lower extreme, layer board and square slide bar pass through the bolt and link to each other, the rubber pad be located layer board bottom, rubber pad and layer board bond and link to each other, vibration point gum machine construct and run through rubber pad and layer board, vibration point gum machine construct and pass through the screw thread with the layer board and link to each other.

2. A highly efficient reciprocating dispensing mechanism as claimed in claim 1, wherein said oscillating disc is provided with two oscillating grooves, symmetrically arranged with respect to the oscillating disc.

3. A highly efficient reciprocating dispensing mechanism as claimed in claim 2, wherein said oscillating slot is oval in shape and extends through the body of the oscillating disc.

4. A highly efficient reciprocating dispensing mechanism as claimed in claim 1, wherein said limiting head is further provided with a crash pad, said crash pad is located at the upper end of the limiting head, and said crash pad is connected with the limiting head through a bolt.

5. A high efficiency reciprocating dispensing mechanism as claimed in claim 4, wherein the axis of said crash pad coincides with the axis of a square slide bar.

6. The high-efficiency reciprocating dispensing mechanism of claim 1, wherein the number of the guiding and limiting mechanisms is 2, and the guiding and limiting mechanisms are arranged up and down symmetrically along the limiting frame.

7. The efficient reciprocating dispensing mechanism of claim 6, wherein the guiding and limiting mechanism comprises limiting plates and elastic guiding mechanisms symmetrically arranged along the limiting plates, the limiting plates are located outside the limiting frames, the limiting plates are connected with the limiting frames through bolts, and the elastic guiding mechanisms penetrate through the limiting plate main bodies.

8. The efficient reciprocating dispensing mechanism of claim 7, wherein the elastic guide mechanism comprises an adjusting screw, a steel ball and a compression spring, the lower end of the adjusting screw extends into the limiting plate, the steel ball penetrates through the limiting plate to be in contact with the square sliding rod, and the compression spring is located between the adjusting screw and the steel ball.