# Patent

## Title
Apparatus and method for grinding compression line spring

## Abstract

Disclosed herein is an apparatus for grinding a compression line spring. The apparatus includes a lower chain conveyor (100), an upper chain conveyor (200), and grinding units (300). The lower chain conveyor includes chain units (110) and (110′) provided facing each other at positions spaced apart from each other. Each chain unit (110), (110′) includes first V-shaped blocks (115) for supporting compression line springs. The upper chain conveyor includes chain units (210) and (210′) provided facing each other at positions spaced apart from each other. Each chain unit (210), (210′) includes second V-shaped blocks (215) for compressing downward upper portions of the compression line springs seated on the first V-shaped blocks (115) and thus supporting the compression line springs. The grinding units (300) grind seat surfaces formed on opposite ends of the compression line springs that are being moved by the lower chain conveyor and the upper chain conveyor.

## Background
TECHNICAL FIELD
The present invention generally relates to apparatuses and methods for grinding seat surfaces formed on opposite ends of compression line springs and, more particularly, to an apparatus and method for grinding seat surfaces formed on opposite ends of compression line springs while the compression line springs are continuously transferred by a chain conveyor.
BACKGROUND ART
FIG. 1 is a view showing the structure of a compression line spring.
Generally, the compression line spring 10 is a spring that is manufactured by spirally winding a linear spring material. The compression line spring is processed through a seat-surface grinding process so that seat surfaces 10a and 10b formed on opposite ends of the compression line spring 10 are oriented perpendicular to a shaft S of the spring 10.
FIG. 2 is a plan view showing the construction of a conventional apparatus for grinding compression line springs. FIG. 3 is a side view showing the construction of the conventional grinding apparatus.
The conventional grinding apparatus includes a turntable 20 that rotates with a plurality of compression line springs 10 fixed to the turntable 20, and a plurality of grinding wheels 30 that are disposed above and below the turntable 20 and face each other with the turntable 20 disposed therebetween. The grinding wheels 30 grind the seat surfaces of the compression line springs 10 that are being transferred by the rotation of the turntable.
A plurality of installation holes 21 are formed in the turntable 20, and compression line springs are fitted into the installation holes 21. The installation holes 21 have diameters corresponding to outer diameters of the compression line springs to be ground so that the compression line springs can be reliably supported on the turntable while the operation of grinding the compression line springs is conducted.
However, the conventional grinding apparatus has the following problems.
When it is required in a separate operation to grind compression line springs having a different dimension, the entirety of the turntable must be replaced with another one. This makes the work complex. In addition, different kinds of turntables corresponding to the kinds of compression line springs must be prepared, thus increasing the cost of equipment.
That is, the installation holes formed in the turntable cannot be adjusted in diameter. Thus, it is impossible to install compression line springs having outer diameters greater than the diameter of the installation holes. In the case of compression line springs having excessively smaller outer diameters than the diameter of the installation holes, when the grinding process is conducted, the compression line springs cannot be reliably supported. Thus, vibrations may occur. Furthermore, there is the likelihood of the compression line springs being removed from the installation holes, which may lead to an accident.
Therefore, there is a problem in that the turntable must be replaced with another one when it is required to grind other kinds of compression line springs.
DISCLOSURE
Technical Problem
Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide apparatus and method for grinding compression line springs that can grind different kinds of compression line springs without replacing a main part with another one so long as the diameters of the compression line springs fall within a predetermined range.
Technical Solution
In order to accomplish the above object, in an aspect, the present invention provides an apparatus for grinding a compression line spring, including: a lower chain conveyor including a pair of chain units provided facing each other at positions spaced apart from each other, each of the chain units including a plurality of first V-shaped blocks for supporting compression line springs; an upper chain conveyor including a pair of chain units provided facing each other at positions spaced apart from each other, each of the chain units comprising a plurality of second V-shaped blocks for compressing downward upper portions of the compression line springs seated on the first V-shaped blocks and thus supporting the compression line springs; and a plurality of grinding units for grinding seat surfaces formed on opposite ends of the compression line springs that are moved by the lower chain conveyor and the upper chain conveyor.
In another aspect, the present invention provides a method for grinding a compression line spring, including: an operation (S110) of fixing compression line springs in place using first V-shaped blocks and second V-shaped blocks respectively provided in a lower chain conveyor and an upper chain conveyor and transferring the compression line springs in a horizontal direction using the lower chain conveyor and the upper chain conveyor; and an operation (S120) of grinding, using grinding units, seat surfaces formed on opposite ends of the compression line springs that are transferred in the operation (S110).
As described above, in apparatus and method for grinding compression line springs according to the present invention, when it is required in a separate operation to grind compression line springs having a different dimension, appropriate conditions for grinding the compression line springs can be easily embodied by simple setting manipulation without need for conventional complex operation of replacing a turntable with another one. Therefore, the efficiency of the operation of grinding compression line springs can be enhanced. Moreover, because there is no need for preparing different kinds of turntables, related cost can be reduced.



DESCRIPTION OF DRAWINGS
FIG. 1 is a view showing the structure of a compression line spring;
FIG. 2 is a plan view showing the construction of a conventional apparatus for grinding a compression line spring;
FIG. 3 is a side view showing the construction of the conventional grinding apparatus;
FIG. 4 is a front view illustrating the construction of a grinding apparatus according to the present invention;
FIG. 5 is a plan view illustrating the construction of the grinding apparatus according to the present invention;
FIG. 6 is a side view illustrating critical parts of the grinding apparatus according to the present invention;
FIG. 7 is a front view illustrating the construction of a lower chain conveyor according to the present invention;
FIG. 8 is a plan view illustrating the construction of the lower chain conveyor according to the present invention;
FIG. 9 is a perspective view showing the coupling of first V-shaped blocks to a chain according to the present invention;
FIG. 10 is a front view illustrating the construction of an upper chain conveyor according to the present invention;
FIG. 11 is a plan view illustrating the construction of the upper chain conveyor according to the present invention;
FIG. 12 is a perspective view showing the coupling of second V-shaped blocks to a chain according to the present invention;
FIG. 13 is a view showing in detail the installation of pressing-blocks according to the present invention;
FIG. 14 is a side view showing the installation structure of grinding units according to the present invention;
FIG. 15 is a front view showing the structure of a distance adjustment means according to the present invention; and
FIG. 16 is a side view showing the structure of the distance adjustment means according to the present invention.



DESCRIPTION OF THE REFERENCE NUMERALS IN THE DRAWINGS


    
    
        100: lower chain conveyor 110: front chain unit
        110′: rear chain unit 115: first V-shaped block
        118: spline shaft 130,130′: first screw shaft
        140: transfer nut 150: belt
        200: upper chain conveyor 210: front chain unit
        210′: rear chain unit 214: chain
        215: second V-shaped block 218: spline shaft
        230: second screw shaft 240: transfer nut
        250: motor 260: compression block
        261: pin 270: spring
        300: grinding unit 330; transfer table
        340: transfer nut 350: third screw shaft
        360: fastening plate 370: transfer nut
        380: fourth screw shaft 400: motor
        410: reducer 411,412: output shaft
        420: first universal joint 430: second universal joint
        500: distance adjustment means 510: lift frame
        520: rail 531,532: inclined block
        531′, 532′: inclined rail 540: fifth screw shaft
        543: handle 551,552: fixed block
        560: fixed frame
    
    


BEST MODE
Hereinafter, an embodiment of the present invention will be described with reference to the attached drawings. If in the specification, detailed descriptions of well-known functions or configurations would unnecessarily obfuscate the gist of the present invention, the detailed descriptions will be omitted.
FIG. 4 is a front view illustrating critical parts of an apparatus for grinding a compression line spring according to the present invention. FIG. 5 is a plan view illustrating the critical parts of the grinding apparatus according to the present invention. FIG. 6 is a side view illustrating the critical parts of the grinding apparatus according to the present invention.
The grinding apparatus according to the present invention is characterized in that with regard to a compression line spring 10 having an outer diameter within a predetermined range, a part for fixing the compression line spring in place can be easily re-set by simple manipulation without need for replacing it with another one, and then operation of grinding the compression line spring can be conducted. The grinding apparatus includes a lower chain conveyor 100, an upper chain conveyor 200, and grinding units 300.
Reference numeral 280 of FIG. 6 denotes a nozzle that sprays cutting oil to cool heat generated during a process of grinding the compression line spring and prevent dust from scattering.
FIG. 7 is a front view illustrating the construction of the lower chain conveyor according to the present invention. FIG. 8 is a plan view illustrating the construction of the lower chain conveyor according to the present invention. FIG. 9 is a perspective view showing the coupling of first V-shaped blocks to a chain according to the present invention.
The lower chain conveyor 100 includes a pair of chain units 110 and 110′. The chain units 110 and 110′ are disposed facing each other at positions spaced apart from each other.
Meanwhile, the two chain units 110 and 110′ substantially have the same construction with a difference only in position; therefore, the same reference numerals are used to explain parts of the chain units 110 and 110′.
Each chain unit 110, 110′ includes a frame 111, sprockets 112 and 113 installed on respective opposite left and right ends of the frame 111, a chain 114 that is supported by the frame 111 and the sprockets 112 and 113 and rotated therearound, and a plurality of first V-shaped blocks 115 that is installed on the chain 114 and provide space to seat the compression line springs therein.
Each first V-shaped block 115 is coupled to the chain 114 by a pin 116 fastened through the chain 114. The first V-shaped block 115 coupled to the chain 114 by the pin 116 is configured so as to be finely rotatable around the pin 116. Due to the above-mentioned configuration, the first V-shaped block 115 is finely rotated around the pin 116 depending both on the orientation of the compression line spring seated onto the first V-shaped block 115 and on the orientation of a second V-shaped block compressing and supporting an upper end of the compression line spring and is thus oriented corresponding to the orientations of the compression line spring and the second V-shaped block. In this way, the first V-shaped block 115 can more stably support the compression line spring.
Meanwhile, the sprockets 112 and 113 that are provided in the two chain units 110 and 110′ spaced apart from each other are respectively coupled to spline shafts 117 and 118 each of which extends a predetermined length through the two chain units 110 and 110′, whereby the sprockets 112 and 113 are rotated along with the spline shafts 117 and 118. Furthermore, the chain unit 110 disposed at a front side of the apparatus is configured to be movable along the spline shaft 117 and 118 toward or away from the rear chain unit 110′.
Therefore, a distance D1 between the two chain units 110 and 110′ can be appropriately adjusted by moving the front chain unit 110 depending on the length of the compression line springs.
To achieve the purpose of moving the front chain unit 110, the front chain unit 110 and the rear chain unit 110′ are connected to each other by one or more linear guides 120. The front chain unit 110 is configured to move along the linear guides 120.
The front chain unit 110 includes transfer nuts 140 that are coupled to one or more first screw shafts 130 and 130′ which horizontally extend a predetermined length through the rear chain unit 110′. Therefore, the front chain unit 110 is moved along with the transfer nuts 140 by rotation of the first screw shafts 130 and 130′.
FIGS. 7 and 8 illustrate the configuration in which the first screw shafts 130 and 130′ are respectively installed in the opposite left and right sides of the lower chain conveyor 100. In this embodiment, the first screw shafts 130 and 130′ are automatically rotated by a power source such as a motor, but they may be configured to be manually rotated by an operator.
FIG. 10 is a front view illustrating the construction of the upper chain conveyor according to the present invention. FIG. 11 is a plan view illustrating the construction of the upper chain conveyor according to the present invention. FIG. 12 is a perspective view showing the coupling of second V-shaped blocks to the chain according to the present invention. FIG. 13 is a view showing in detail the installation of pressing blocks according to the present invention.
The upper chain conveyor 200 includes a pair of chain units 210 and 210′. The chain units 210 and 210′ are disposed facing each other at positions spaced apart from each other. Preferably, the chain units 210 and 210′ are respectively disposed vertically above the chain units 110 and 110′ of the lower chain conveyor 100.
According to the above construction, the second V-shaped blocks 215 provided in the chain units 210 and 210′ of the upper chain conveyor 200 are disposed vertically above the respective first V-shaped blocks 115 provided in the chain units 110 and 110′ of the lower chain conveyor 100. The first and second V-shaped blocks face each other with the compression line springs interposed therebetween and thus fix the compression line springs in place.
Meanwhile, the two chain units 210 and 210′ substantially have the same construction with a difference only in position; therefore, the same reference numerals are used to explain parts of the chain units 210 and 210′.
Each chain unit 210, 210′ includes a frame 211, sprockets 212 and 213 installed on respective opposite left and right ends of the frame 211, a chain 214 that is supported by the frame 211 and the sprockets 212 and 213 and rotated therearound, and a plurality of second V-shaped blocks 215 that is installed on the chain 214 and compresses and supports the upper portions of the compression line springs seated on the respective first V-shaped blocks 115.
In the same manner as the first V-shaped block 115, each second V-shaped block 215 is coupled to the chain 214 by a pin 216 fastened through the chain 210 and configured so as to be finely rotatable around the pin 216.
Meanwhile, the sprockets 212 and 213 that are provided in the two chain units 210 and 210′ spaced apart from each other are respectively coupled to spline shafts 217 and 218 each of which extends a predetermined length through the two chain units 210 and 210′, whereby the sprockets 212 and 213 are rotated along with the spline shafts 217 and 218. Furthermore, the chain unit 210 disposed at the front side of the apparatus is configured to be movable along the spline shaft 217 and 218 toward or away from the rear chain unit 210′.
The sprockets 212 that are disposed at the left side of the associated drawing are idle sprockets, which rotate under no-load conditions without being connected to any power source. The idle sprockets 212 may be coupled to each other by a general shaft rather than by the spline shaft 217.
According to the above-mentioned construction, a distance D2 between the two chain units 210 and 210′ can be appropriately adjusted by moving the front chain unit 210 depending on the length of the compression line springs.
To achieve the purpose of moving the front chain unit 210, the front chain unit 210 and the rear chain unit 210′ are connected to each other by one or more linear guides 220. The front chain unit 210 is configured to move along the linear guides 220.
Furthermore, the front chain unit 210 includes a transfer nut 240 that is coupled to a second screw shaft 230 that horizontally extends a predetermined length through the rear chain unit 210′. Therefore, the front chain unit 210 is moved along with the transfer nut 240 by rotation of the second screw shaft 230.
Preferably, the second screw shaft 230 and the first screw shafts 130 and 130′ are connected and interlocked with each other so that the front chain unit 210 of the upper chain conveyor 200 and the front chain unit 110 of the lower chain conveyor 100 can be moved together.
For this, the first screw shafts 130 and 130′ and the second screw shaft 230 are connected to each other by a power transmission means such as chains or belts (150: refer to FIGS. 8 and 11). According to this construction, when the first screw shafts 130 and 130′ rotate, the second screw shaft 230 rotates along with the first screw shafts 130 and 130′. In the same manner, when the second screw shaft 230 rotates, the first screw shafts 130 and 130′ also rotate along with the second screw shaft 230.
With regard to the interlocking rotation of the first screw shaft 130 and 130′ and the second screw shaft 230, the second screw shaft 230 may be connected to a motor 250 and rotated by it so that the two front chain units 110 and 210 can be moved by the operation of the motor 250. Alternatively, the two front chain units 110 and 210 may be moved by manually manipulating the first screw shafts 130 and 130′.
A left-right width (L2: refer to FIG. 10) of the upper chain conveyor 200 is shorter than a left-right width (L1: refer to FIG. 7) of the lower chain conveyor 100.
Preferably, the upper chain conveyor 200 further includes a plurality of compression blocks 260 that press the chain 214 downward so that the second V-shaped blocks 215 can reliably come into close contact with the compression line springs, and a plurality of springs 270 that elastically support the compression blocks 260.
The compression blocks 260 are installed under the frames 211 of the chain units 210 and 210′. The compression blocks 260 installed in the above manner are disposed vertically above a portion of the chain 214 that passes under lower ends of the frames 211 and thus compress the chain 214 downward.
Meanwhile, each of the compression blocks 260 compresses the chain 214 downward so that one or two corresponding second V-shaped blocks 215 can come into close contact with the respective compression line springs. For reference, FIG. 13 illustrates the structure in which two second V-shaped blocks 215 are compressed by a single compression block 260.
The compression blocks 260 are coupled to each other by pins 261. According to this construction, each compression block 260 is configured so as to be restrictively rotatable around the corresponding pin 261, whereby each two of the second V-shaped blocks 215 that are compressed by a corresponding single compression block 260 can be compressed under different conditions.
That is, there may be a deviation in orientation or outer diameter of the compression line springs 10 supported by the first and second blocks 115 and 215. However, if the second V-shaped blocks 215 are compressed at the same pressure without taking such deviation into account, the second V-shaped block 215 that is disposed above the compression line spring having a comparatively small diameter may not reliably come into close contact with the upper portion of the compression line spring. In this case, the compression line spring may be removed from its correct position during the process of grinding the seat surfaces of the compression line spring.
However, in the present invention, the compression blocks 260 are coupled to each other by the pins 261, whereby the compression blocks 260 are configured so as to be slightly movable although this movement is restricted. In this case, appropriate movement of the compression blocks 260 compensates for the deviation in orientation or outer diameter of the compression line springs. Consequently, the compression line springs can be more stably supported by the V-shaped blocks.
The lower chain conveyor 100 and the upper chain conveyor 200 are operated by power provided from a single motor.
In more detail with reference to FIG. 5, the motor 400 for providing power to operate the lower chain conveyor 100 and the upper chain conveyor 200 is connected to a reducer 410. The reducer 410 reduces the speed of rotation input from the motor 400 at a predetermined ratio and then outputs power reduced in speed via two output shafts 411 and 412. Any one of the two output shafts 411 and 412 provided in the reducer 410 is coupled by a first universal joint 420 to the spline shaft 118 provided in the lower chain conveyor 100. The other output shaft 411 or 412 is coupled by a second universal joint 430 to the spline shaft (218: refer to FIG. 11) provided in the upper chain conveyor 200.
Meanwhile, although the internal construction of the reducer 410 is not illustrated in detail, a plurality of gears are provided in the reducer 410 so as to reduce the speed of rotation input from the motor 400 at a predetermined ratio. Such construction of the reducer 410 is a well known and widely used technique. Therefore, further explanation of the reducer 410 will be omitted.
FIG. 14 is a side view illustrating the installation structure of the grinding units according to the present invention.
The grinding units 300 are disposed on opposite front and rear sides of the lower chain conveyor 100 and grind seat surfaces of opposite ends of the compression line springs 10 that are being moved by the lower chain conveyor 100 and the upper chain conveyor.
Some of the grinding units 300 are disposed ahead of the lower chain conveyor 100, and the other grinding units 300 are disposed behind the lower chain conveyor 100.
Each grinding unit 300 includes a motor 310, and a grinding wheel 320 that is rotated by the motor 310 to conduct the grinding operation.
Preferably, each grinding unit 300 is configured such that an operator can adjust the position thereof depending both on the length of the compression line spring 10 and on the depth of cut. For this, a transfer table 330 is provided under the grinding unit 300, and a transfer nut 340 and a third screw shaft 350 are installed to transfer the transfer table 330.
Meanwhile, the transfer table 330, the transfer nut 340, and the third screw shaft 350 are installed on each of the opposite front and rear sides of the lower chain conveyor 100 so that the grinding units disposed ahead of the lower chain conveyor 100 and the grinding units disposed behind the lower chain conveyor 100 can be independently moved.
The grinding units 300 are fastened on an upper surface of each transfer table 330.
The transfer nut 340 is fastened to a lower surface of the transfer table 330.
The third screw shaft 350 extends in the front-rear direction perpendicular to the lower chain conveyor 100 and is coupled to the transfer nut 340.
When the operator rotates a handle 351 coupled to the third screw shaft 350, the transfer nut 340 is moved by the rotation of the third screw shaft 350. The transfer table 330 is thus moved by the movement of the transfer nut 340, whereby the position of the grinding unit 300 can be adjusted.
Meanwhile, to individually adjust the position of each grinding unit 300, a fastening plate 360 is installed under a lower surface of each grinding unit 300. A transfer nut 370 is provided under a lower surface of the fastening plate 360. A fourth screw shaft 380 is installed on an upper surface of the transfer table 330 and is coupled to the transfer nut 370 so that the transfer nut 370 is moved by rotation of the fourth screw shaft 380.
Preferably, the pitch of the fourth screw shaft 380 is less than that of the third screw 350 so that the position of each grinding unit 300 can be more precisely adjusted by the fourth screw shaft 380.
FIG. 15 is a front view showing the structure of a distance adjustment means according to the present invention. FIG. 16 is a side view showing the structure of the distance adjustment means according to the present invention.
If it is required in a separate operation to grind compression lines springs having a different dimension, the distance between the first V-shaped block 115 and the second V-shaped block 215 must be adjusted to correspond to the outer diameter of the compression line springs.
The distance adjustment means 500 for adjusting the distance between the first and second V-shaped blocks 115 and 215 includes a lift frame 510 includes a lift frame 510, a rail 520, inclined blocks 531 and 532, a fifth screw shaft 540, and fixed blocks 551 and 552.
The lift frame 510 is coupled to the upper chain conveyor 200 and configured to move upward or downward along with the upper chain conveyor 200.
The lift frame 510 has a reverse U shape that is open on a lower end thereof. An upper end of the upper chain conveyor 200 is inserted into the lift frame 510.
The rail 520 extends in the left-right direction on an upper end of the lift frame 510. FIG. 16 illustrates the structure in which two rails 520 are spaced apart from each other by a predetermined distance and installed parallel to each other.
The inclined blocks 531 and 532 are coupled to the rails 520 and configured to move along the rails 520. Inclined rails 531′ and 532′ having a predetermined inclination angle ⊖ are respectively installed on the inclined blocks 531 and 532.
In this embodiment, the two inclined blocks 531 and 532 are provided. The two inclined blocks 531 and 532 are installed on the rails 520 and configured to form a symmetrical structure facing each other at positions spaced apart from each other by a predetermined distance.
The fifth screw shaft 540 is installed to pass through the two inclined blocks 531 and 532 coupled to the rails 520 and is rotatably coupled to a support 511 installed on the lift frame 510.
The fifth screw shaft 540 includes a left-handed screw part 541 that is formed on one side of the fifth screw shaft 540 based on a medial portion thereof, and a right-handed screw part 542 that is formed on the other side thereof. Any one of the inclined blocks 531 is coupled to the left-handed screw part 541, and the other inclined block 532 is coupled to the right-handed screw part 542 so that when the fifth screw shaft 540 is rotated, the two inclined blocks 531 and 532 are moved toward or away from each other.
In this embodiment, the two fixed blocks 551 and 552 are respectively coupled to the inclined blocks 531 and 532. The fixed blocks 551 and 552 are fastened to a fixed frame 560 such that the fixed blocks 551 and 552 are disposed vertically above the respective inclined blocks 531 and 532.
In this way, the fixed blocks 551 and 552 installed on the fixed frame 560 are coupled to the inclined rails 531′ and 532′ provided on the inclined blocks 531 and 532.
Therefore, when the operator rotates a handle 543 provided on the fifth screw shaft 540, the two inclined blocks 531 are moved toward or away from each other depending on the direction in which the handle 543 is rotated. During this process, the two inclined blocks 531 and 532 are moved upward or downward by the inclined rails 531′ and 532′ and the fixed blocks 551 and 552 and thus move the lift frame 510 upward or downward. Then, the upper chain conveyor 200 is moved upward or downward by the vertical movement of the lift frame 510, whereby the distance between the first V-shaped block 115 and the second V-shaped block 215 can be adjusted.
A method for grinding compression line springs using the grinding apparatus according to the present invention having the above-mentioned construction includes: operation S110 of fixing the compression line springs 10 in place using the first and second V-shaped blocks 115 and 215 provided in the lower and upper chain conveyors 100 and 200 and transferring the compression line springs in the horizontal direction using the lower and upper chain conveyors 100 and 200; and operation S120 of grinding, using the grinding units 300, the seat surfaces formed on the opposite ends of the compression line springs that are being transferred in operation S110.
In operation S110, the compression line springs 10 are seated on the first V-shaped blocks 115 provided in the lower chain conveyor 100, and then the lower chain conveyor 100 and the upper chain conveyor 200 are operated.
Such operation S110 preferably includes supplying compression line springs from a separate compression-line-spring supply apparatus to the first V-shaped blocks 115 while the lower and upper chain conveyors 100 and 200 are operated.
A well known robot arm or a well known automatic part feeder may be used as the compression-line-spring supply apparatus.
Meanwhile, the compression line springs seated on the first V-shaped blocks 115 of the lower chain conveyor 100 are moved by the operation of the lower chain conveyor 100. After the compression line springs have moved a predetermined distance, upper portions thereof are compressed by the second V-shaped blocks 215 provided in the upper chain conveyor 200. Thereby, the compression line springs can be stably fixed in place by the first and second V-shaped blocks 115 and 25.
As such, during the process of using the first and second V-shaped blocks 115 and 215 to fix the compressing line springs in place and move them, the compression blocks 260 compress the chain 214 at a predetermined pressure corresponding to conditions of the compression line springs. Thereby, the second V-shaped blocks 215 can reliably come into close contact with the compression line springs. Here, the conditions of the compression line springs may include a state whereby the compression line springs are seated on the first V-shaped blocks 115, or a deviation in the outer diameter of the compression line springs.
Preferably, operation S101 of adjusting both the distance between the front chain unit 110 and the rear chain unit 110′ of the lower chain conveyor 100 and the distance between the front chain unit 210 and the rear chain unit 210′ of the upper chain conveyor 200 precedes operation S110.
In other words, when it is required in a separate operation to grind compression line springs having a different dimension, for example, a different length, the front chain units 110 and 210 are moved and set to positions corresponding to the length of compression line springs to be ground so that the first V-shaped block 115 and the second V-shaped block 215 can support the compression line springs at appropriate positions.
The movement of the front chain units 110 and 210 may be embodied by the operator in such a way that the operator directly rotates the first screw shafts 130 and 130′ provided in the lower chain conveyor 100. Alternatively, it may be embodied by the operation of the motor 250 connected to the second screw shaft 230.
The method may further include operation S102 of adjusting the height of the upper chain conveyor 200 that is combined with operation S101.
Operation S102 is conducted to grind other compression line springs with a different diameter. When the operator rotates the handle 543 provided on the fifth screw shaft 540, the inclined blocks 531 and 532 are moved by the rotation of the fifth screw shaft 540. Then, the inclined blocks 531 and 532 are slowly moved downward or upward by the fixed blocks 551 and 552 and the inclined rails 531′ and 532′, whereby the height of the upper chain conveyor 200 can be adjusted.
In operation S120, the compression line springs are moved by the operation of the upper and lower chain conveyors 200 and 100 and thus successively pass via the grinding units 300, whereby the seat surfaces formed on the opposite ends of the compression line springs are ground.
Before operation S120 is conducted, the operator rotates the third screw shaft 350 or the fourth screw shaft 380 and thus adjusts the position of the grinding unit 300, thereby adjusting the depth of cut.
As described above, in the apparatus and method for grinding compression line springs according to the present invention, when it is required in a separate operation to grind compression line springs having a different dimension, appropriate conditions for grinding the compression line springs can be easily embodied by simple setting manipulation without need for the conventional complex operation of replacing a turntable with another one. Therefore, the efficiency of the operation of grinding compression line springs can be enhanced. Moreover, because there is no need for preparing different kinds of turntables, related costs can be reduced.
Although the embodiment of the present invention has been disclosed for illustrative purposes, it will be appreciated that the present invention is not limited thereto, and those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention.

## Claims

1. An apparatus for grinding a compression line spring, comprising:
a lower chain conveyor including a pair of first chain units provided facing each other at positions spaced apart from each other, each of the first chain units comprising a plurality of first V-shaped blocks for supporting compression line springs;
an upper chain conveyor including a pair of second chain units provided facing each other at positions spaced apart from each other, each of the second chain units comprising a plurality of second V-shaped blocks for compressing downward upper portions of compression line springs seated on the first V-shaped blocks and thus supporting the compression line springs;
a plurality of grinding units for grinding seat surfaces formed on opposite ends of the compression line springs that are moved by the lower chain conveyor and the upper chain conveyor;
a plurality of compression blocks provided in the upper chain conveyor and pressing a chain downward so that the second V-shaped blocks are brought into close contact with the compression line springs; and
a plurality of springs installed in the upper chain conveyor and elastically supporting the compression blocks.

2. The apparatus of claim 1, wherein, the first chain units of the lower chain conveyor comprise; a lower front chain unit that is configured so as to be movable toward or away from a lower rear chain unit depending on a length of the compression line springs, and
wherein the second chain units of the upper chain conveyor comprise; an upper front chain unit that is configured so as to be movable toward or away from an upper rear chain unit depending on the length of the compression line springs.

3. The apparatus of claim 2, wherein the front chain unit of the lower chain conveyor is coupled to one or more first screw shafts by a transfer nut, the first screw shafts horizontally extending through the lower rear chain unit,
the front chain unit of the upper chain conveyor is coupled to a second screw shaft by a transfer nut, the second screw shaft horizontally extending through the upper rear chain unit, and
the first screw shafts and a second screw shaft are connected to each other by a belt and thus interlocked with each other.

4. The apparatus of claim 3, wherein the second screw shaft is connected to a motor and rotated by operation of the motor.

5. The apparatus of claim 1, wherein the plurality of compression blocks are coupled to each other by a pin.

6. The apparatus of claim 1, further comprising:
a distance adjustment mechanism for moving the upper chain conveyor upward or downward and adjusting a distance between the first V-shaped blocks and the second V-shaped blocks.

7. The apparatus of claim 6, wherein the distance adjustment mechanism comprises:
a lift frame coupled to the upper chain conveyor;
a pair of rails installed on an upper end of the lift frame and extending in a left-right direction;
a pair of inclined blocks provided so as to be movable along the rails, with inclined rails installed on upper ends of the respective inclined blocks;
a fifth screw shaft configured to pass through the two inclined blocks, the fifth screw shaft rotating when an operator manipulates a handle and thus moving the inclined blocks such that the inclined blocks move toward or away from each other; and
a pair of fixed blocks installed on a fixed frame above the respective two inclined blocks, the fixed blocks being respectively coupled to the inclined rails so that when the inclined blocks are moved, the fixed blocks guide the inclined blocks such that the inclined blocks are moved upward or downward by an inclination angle of the inclined rails.

8. The apparatus of claim 1, further comprising: a motor providing power for driving the lower chain conveyor and the upper chain conveyor;
a reducer connected to the motor and including two output shafts;
a first universal joint connecting the first output shaft of the reducer to a first spline shaft extending from the lower chain conveyor; and
a second universal joint connecting the second output shaft of the reducer to a second spline shaft extending from the upper chain conveyor.

9. The apparatus of claim 1, further comprising:
a transfer table having an upper surface on which the plurality of grinding units is installed;
a transfer nut fastened to a lower surface of the transfer table; and
a third screw shaft coupled to the transfer nut, the third screw shaft rotating by manipulation of the operator and thus moving the transfer nut and the transfer table toward or away from the compression line springs.

10. The apparatus of claim 9, further comprising:
a fastening plate installed on a lower end of each of the grinding units;
a transfer nut installed under a lower surface of the fastening plate; and
a fourth screw shaft installed on the transfer table and coupled to the transfer nut, the fourth screw shaft rotating by manipulation of the operator and thus transferring the transfer nut.