WO2007066847A1

WO2007066847A1 - Auto-grinder and controlling method thereof

Info

Publication number: WO2007066847A1
Application number: PCT/KR2005/004387
Authority: WO
Inventors: Soo Ryong Jung; O Chol Shin; Hyung Jae Shin; Seok Il Lee
Original assignee: Solomon Mechanics Co., Ltd
Priority date: 2005-12-09
Filing date: 2005-12-20
Publication date: 2007-06-14
Also published as: KR100745017B1; KR20070060680A

Abstract

Provided is an auto-grinder that includes an ultraprecision grinder (160, 160'), a grinder roller (130), an operating sensor (134a, 134b, 134c, 134d), a roller supporting member (120), and a table rotating member (110). The ultraprecision grinder (160, 160') includes a grinding abrasive film (162), a grinder head (162), and a plunger (210). The grinder roller (130) rotates and conveys a work piece (w). The operating sensor (134a, 134b, 134c, 134d) senses the work piece (w). The roller supporting member (120) supports the grinder roller (130). The table rotating member (110) is rotatably installed on a supporting die, and supports the pair of grinder rollers (130) and the roller supporting member (120). The ultraprecision grinder (160 and 160') selectively grinds the work piece (w) if it is present, and the grinder head (200) is rotatably installed on the plunger (210). The inventive auto-grinder increases grinding accuracy.

Description

AUTO-GRINDER AND CONTROLLING METHOD THEREOF

Technical Field

[1] The present invention relates to a grinding machine, and more particularly, to an auto-grinder that can automatically operate in an ultraprecision grinding mode according to whether a work piece is inputted, and to a controlling method of the same.

[2]

Background Art

[3] Grinding (or polishing) generally refers to a finishing process in manufacturing that uses a grain or powder with a high degree of hardness to grind and clean the surface of a work piece, for a high-quality finish.

[4] Grinding processes according to the related art use abrasive grinding tools, such as a grindstone. Grinding, cutting, polishing, honing, etc. using grinding abrasives is broadly referred to as grinding.

[5] That is, grinding, according to the related art, is performed with a simple configuration consisting of a motor (not shown) that rotates a grindstone 20 attached to the motor through a shaft, as shown in Fig. 1. Thus, a user must physically grasp a work piece 30 to put it in contact with the round surface of the grindstone 20 so that it can be ground.

[6] Such a manually -rendered contacting of the work piece 30 to the grindstone 20 limits the degree of grinding precision and induces the possibility of accidents occurring.

[7] In order to obviate the above difficulties, a jig grinder (not shown), on which a work piece 30 is fastened and moved manually with respect to an operating grinding tool, is employed. The jig grinder, however, is still prone to the occurrence of accidents and lacks precision.

[8]

Disclosure of Invention

Technical Problem

[9] To solve the above problem, the present invention provides an auto-grinder that can automatically operate in an ultraprecision grinding mode according to whether a work piece is inputted.

[10] Another object of the present invention is to provide an auto-grinder having a

grinder head (for guiding a film abrasive so that it contacts a surface of a work piece) that is rotatably installed on the end of a plunger and a plurality of operating sensors for sensing if a work piece has been inputted. [11] A further object of the present invention is to provide an auto-grinder having a table rotating member capable of effectively negating twisting of grinder rollers that occurs during the setting of a pair of grinder rollers.

[12]

Technical Solution

[13] According to an aspect of the present invention, there is provided an auto-grinder including: a film-type ultraprecision grinder including a grinding abrasive film for contacting and grinding a surface of a work piece, a grinder head for guiding the grinding abrasive film to contact the surface of the work piece, and a plunger for supporting the grinder head; a grinder roller installed as a pair to mutually intersect at a predetermined angle at a side of the ultraprecision grinder, having an outer diameter that decreases from both ends toward a middle thereof, and for simultaneously rotating the work piece and conveying the work piece to one end thereof; an operating sensor for sensing an insertion of the work piece; a roller supporting member for supporting both respective ends of the grinder roller; and a table rotating member rotatably installed on a top of a supporting die that supports a plurality of components, the table rotating member supporting the pair of grinder rollers and the roller supporting member, wherein the ultraprecision grinder selectively operates according to whether the operating sensor senses that the work piece has been inserted, and the grinder head is rotatably installed on an end of the plunger.

[14] The ultraprecision grinder may be provided in duplicate or more and installed along a common line next to one another.

[15] The ultraprecision grinder may further include: a feeding roller for supplying the grinding abrasive film; a take-up roller installed at a side of the feeding roller, for taking up the grinding abrasive film that has been used for grinding the work piece; a plurality of supporting rollers for supporting the grinding abrasive film between the feeding roller and the take-up roller; a vertical actuator installed at a side of the plunger for selectively engaging the grinding abrasive film to the surface of the work piece; a nd a lateral oscillator installed at a side of the plunger for oscillating the plunger laterally over a predetermined parameter.

[16] The table rotating member may include: a turntable rotatably installed for

supporting the grinder roller; and a pin provided at a central portion of the turntable as a center of rotation for the turntable.

[17] The roller supporting member may include: a support bracket provided above the turntable for supporting the grinder roller; a roller bracket for rotatably supporting both ends of the grinder roller; and a controlling plate provided between the support bracket and the roller bracket and installed to be capable of rotating on a surface of the support bracket.

[18] The controlling plate may be installed to be capable of rotating around a rotating pin formed in a central portion thereof.

[19] The grinder roller may include a plurality of dispersing grooves formed on an outer surface thereof for guiding and dispersing residual material formed during grinding.

[20] The grinder head may be provided in plurality, may be cylindrical, and may have a bearing installed on either end thereof.

[21] The grinder head may further have a cushioning layer of ure thane rubber formed on a surface thereof.

[22] The operating sensor may be disposed in a space formed by the pair of grinder rollers, and may be provided in plurality.

[23] The operating sensor may be installed in a pair below each ultraprecision grinder.

[24] The ultraprecision grinder may operate only when both of the installed pair of

operating sensors sense an insertion of the work piece.

[25] According to another aspect of the present invention, there is provided a controlling method for an auto-grinder including: supplying a work piece on top of a pair of grinder rollers; conveying the supplied work piece in one direction; detecting the supplying and conveying of the work piece; supplying liquid coolant to a surface of the work piece; conveying the work piece to a processing location and grinding the surface of the work piece with an ultraprecision grinder; detecting a conveying and discharging of the work piece; blocking the supplying of liquid coolant; and stopping a grinding process and returning the ultraprecision grinder to an original position.

[26] The grinding of the surface of the work piece may include operations of: adjusting a tension of a grinding abrasive film to have a predetermined amount of tension; oscillating the grinding abrasive film in left and right directions; contacting the grinding abrasive film to the surface of the work piece; and grinding the work piece using the grinding abrasive film, wherein the operations may be simultaneously or sequentially performed.

[27] The detecting of the supplying of the work piece may include detecting the work piece with both of a pair of operating sensors contacting the work piece.

[28] The detecting of the discharging of the work piece may include detecting the work piece with only one of the pair of operating sensors contacting the work piece.

[29] The supplying of liquid coolant to and the grinding of the surface of the work piece may be performed simultaneously.

[30] The blocking of the liquid coolant and the returning of the ultraprecision grinder to the original position may be performed simultaneously. Advantageous Effects

[32] An advantage of the auto-grinder according to the present invention is that a work piece is more smoothly finished than in the related art because the present invention uses a pair of ultraprecision grinders having a grinding abrasive film. That is, grinding is done using grinding abrasive film with highly concentrated abrasive particles and two grinders for double grinding of a work piece.

[33] Another advantage of the auto-grinder according to the present invention is that it performs grinding automatically. That is, a pair of grinder rollers mutually disposed at a predetermined angle rotates a work piece while automatically moving it in a direction towards an end thereof, so that continuous grinding of a successive work pieces is possible. Thus, operational efficiency increases.

[34] A further advantage of the auto-grinder according to the present invention is that it includes a plurality of rotatable grinder heads for guiding a grinding abrasive film, provided on the tips (lower ends) of plungers. Consequently, the transfer of the grinding abrasive film is performed smoothly, and external impacts or compression of the grinding abrasive film are absorbed by the respective grinder heads so that the contact between the grinding abrasive film and the work piece is smooth and even.

[35] An additional advantage of the auto-grinder according to the present invention is that a pair of operating sensors is provided below an ultraprecision grinder, and high precision grinding is controlled so that it is performed by the ultraprecision grinder only when both the operating sensors sense the presence of a work piece. Through this controlling of the grinder, grinding is performed only when the work piece is horizontally positioned, so that twisting of the grinding abrasive film, etc. is prevented and the finish of the work piece is smoother while the grinding abrasive film is worn less quickly.

[36]

Brief Description of the Drawings

[37] Fig. 1 is a perspective view showing a grinder according to the prior art being used.

[38] Fig. 2 is a perspective view showing the structure of an auto-grinder according to an embodiment of the present invention.

[39] Fig. 3 is frontal view of an auto-grinder according to an embodiment of the present invention.

[40] Fig. 4 is a partial perspective view of an auto-grinder according to an embodiment of the present invention performing grinding.

[41] Fig. 5 is a perspective view showing the structure of an ultraprecision grinder of an auto-grinder according to an embodiment of the present invention.

[42] Figs. 6a through Fig. 6c are plan and side views of a table rotating member and a roller supporting member according to an embodiment of the present invention, showing a pair of grinder rollers that are supported.

[43] Fig. 7 is an exploded perspective view of the structure of a plunger and grinder heads according to an embodiment of the present invention.

[44] Fig. 8 is a sectional view of a grinder head according to an embodiment of the

present invention.

[45] Fig. 9a and Fig. 9b are a side and a plan view of a pair of grinder rollers according to an embodiment of the present invention that are rotated clockwise.

[46] Fig. 10 is a flowchart of a controlling method for an auto-grinder according to an embodiment of the present invention.

[47] Fig. 11 is a flowchart of a grinding process in a controlling method for an auto- grinder according to an embodiment of the present invention.

[48]

Best Mode for Carrying Out the Invention

[49] Hereinafter, preferred embodiments of a button assembly of a dishwasher according to the present invention will be described in detail with reference to the accompanying drawings.

[50] Fig. 2 is a perspective view showing the structure of an auto-grinder according to an embodiment of the present invention, and Fig. 3 is frontal view of a grinder according to an embodiment of the present invention. Fig. 4 is a partial perspective view of an auto-grinder according to an embodiment of the present invention performing grinding, and Fig. 5 is a perspective view showing the structure of an ultraprecision grinder of an auto-grinder according to an embodiment of the present invention.

[51] Referring to Figs. 2 through 5, a support die 100 is provided below the auto-grinder according to the present invention. The support die 100 is a predetermined height and supports the components to be described below. The support die 100 contains components installed therein such as a roller motor 140 that provides rotational force to the grinding rollers 130 that are described below.

[52] The support die 100 is roughly cube-shaped, and has a die guide 102 protruding a predetermined height from its upper periphery. The die guide 102 prevents liquid coolant and other residual material (to be described below) from leaking to the outside.

[53] The support die 100 has a table rotating member 110 installed above it. Specifically, the table rotating member 110 is formed to contact the top of the support die 100 and slide so that a portion thereof can rotate. This table rotating member 110 is described in further detail below.

[54] A roller supporting member 120 is respectively installed for each roller at the top of the table rotating member. That is, a roller supporting member 120 for supporting a grinder roller 130 (to be described below) at both ends thereof is provided for each grinder roller 130. The ends of the grinder roller 130 are respectively disposed at the left and right on top of the table rotating member 110. Hereinafter, a detailed structural description of the roller supporting member 120 will be given.

[55] A pair of grinder rollers 130 are installed on top of the table rotating member 110 lengthwise from the left to the right. That is, the grinder rollers 130 are installed between the ends of the respective roller supporting members 120 across the top of the table rotating member 110 from left to right. Accordingly, both ends of a grinder roller 130 are supported by the left and right ends of the roller supporting member 120. The grinder roller 130 is formed cylindrically in a predetermined length.

[56] Two grinder rollers 130 of a pair rotate together on their respective axes by means of a roller rotating member (described below) in a clockwise or counter-clockwise direction, so that they turn a work piece (w). That is, a work piece (w) is inserted and supported between the pair of grinder rollers 130, so that the work piece (w) rotates between the rotating grinder 130 rollers by means of friction. For example, if the grinder rollers 130 rotate in a counter-clockwise direction, the work piece (w) rotates in a clockwise direction (refer to Fig. 4).

[57] The pair of grinder rollers 130 is installed to have a gap between the two rollers that is uniform along their lengths, and to also criss-cross the two rollers. The grinder rollers 130 are formed to have circumferences that gradually decrease from both ends towards the middle. That is, when viewed from the front as in Fig. 3, each grinder roller 130 is inclined in opposition to the other at the left and right ends thereof, and the circumferences of the grinder rollers 130 is narrower at the center than at the ends.

[58] Accordingly, a work piece (w) contacting a pair of grinder rollers 130 moves in one direction (to the right in Fig. 3) while it is rotated. The pair of grinder rollers 130 forms a curved surface in a longitudinal direction. That is, the grinder rollers 130 are formed to have decreasing radii from the outer ends towards the centers thereof, so that from a frontal view, the grinder rollers 130 appear to having a substantial radius of a curvature.

[59] Such a pair of grinder rollers 130, having the rollers disposed at a predetermined angle intersecting one another, slidingly contacts the outer surface of a work piece (w) with the outer surfaces of the two rollers, so that the work piece (w) is moved automatically to one side, as shown in Fig. 3.

[60] Here, the grinder rollers 130 may be disposed at an intersecting angle of I⁰- 2°, and preferably, at an angle of 1.5°.

[61] The outer surfaces of the grinder rollers 130 have a plurality of dispersing grooves

132 formed thereon for dispersing residual material created during grinding. That is, dispersing grooves 132 of a predetermined depth are formed on the outer surface of the grinder roller 130 at a predetermined distance from one another, in order to quickly disperse liquid coolant discharged from a liquid coolant nozzle 184 (to be described below) and metal chips ground by a grinding abrasive film 162.

[62] Operating sensors 134a, 134b, 134c and 134d (to be described below) are installed at a predetermined distance from one another between a pair of grinder rollers 130. Accordingly, when a work piece (w) moves in one direction along the pair of grinder rollers 130 (as shown in Fig. 3) and interferes with (contacts) the operating sensors 1 34a, 134b, 134c and 134d, the insertion of the work piece (w) is sensed by the operating sensors 134a, 134b, 134c and 134d.

[63] A roller rotating member is provided at one end of the grinder rollers 130 to impart rotating force thereto. The roller rotating member includes a roller motor 140 for generating rotation force, a drive chain 142 for transferring the force from the roller motor 140, and a roller pulley 144 respectively provided on the right ends of the grinder rollers 130.

[64] Accordingly, the rotational force generated by the roller motor 140 is transferred through the drive chain 142 to the roller pulleys 144, to rotate the grinder rollers 130.

[65] A pulley cover 146 is installed on the outside of the roller pulley 144 to cover the same. A drive belt may be used to transfer the rotational force instead of the drive chain 142.

[66] A grinder support stand 150 is formed above the support die 100 at the rear portion thereof. The grinder support stand 150 is formed to extend a predetermined height from the top rear portion of the support die 100 to support the ultraprecision grinders 160 and 160' to be explained below. The grinder support stand 150 supports a plurality of components installed within and to the rear thereof.

[67] A grinder mounting plate 152 is installed on the left and right frontal portions of the grinder support stand 150. A pair of ultraprecision grinders 160 and 160', for contacting and performing ultra-precision grinding of a work piece (w), are respectively installed on the fronts of the grinder mounting plates 152. That is, a left-side ultraprecision grinder 160 is installed a predetermined distance to the left of a right- side ultraprecision grinder 160' that is installed to the right of the left-side ultra- precision grinder 160.

[68] The pair of ultraprecision grinders 160 and 160' may be formed on the same level and with the same structure. Of course, the ultraprecision grinder 160 and 160' may be provided in triplicate or more, instead of in a pair.

[69] The ultraprecision grinder 160 and 160', as schematically shown in Fig. 5, is a film type grinder that includes a grinding abrasive film 162 that directly contacts and grinds the surface of a work piece, a feeding roll 164 for supplying the grinding abrasive film 162, a take-up roll 166 for taking up the grinding abrasive film 162 after it has been used to grind the work piece below the feeding roll 164, a plurality of supporting rollers 168 for supporting the grinding abrasive film 162 that moves from the feeding roll 164 to the take-up roll 166, a grinder head 200 for guiding the grinding abrasive film 162 to contact the surface of the work piece (w), a plunger 210 for supporting the grinder head 200, a vertical actuator 170 installed above the plunger 210 for moving the plunger 210 and the grinder head 200 vertically so that grinding abrasive film 162 that is supported by the grinder head 200 can selectively contact the surface of a work piece, and a lateral oscillator 172 (not shown) installed on a side of the plunger 210 for moving the plunger 210 and the grinder head 200 laterally back and forth over a predetermined distance.

[70] At least two supporting rollers 168 are provided below the feeding roll 164 and the take-up roll 166, and the plunger 210 is located between the supporting rollers 168. The plunger 210 is removably installed on a plunger bracket 172. The plunger bracket 172 is provided below the vertical actuator 170, and moves vertically together with the vertical actuator 170.

[71] The grinder head 200 is installed at an end (the bottom, in Fig. 5) of the plunger

210. The grinder head 200 is rotatably installed in plurality along a common line from left to right. That is, four grinder heads 200 are installed uniformly on an end (the bottom) of the plunger 210, to guide the grinding abrasive film 162 to contact the surface of a work piece (w). The installation of the grinder head 200 is described in further detail below.

[72] The lateral oscillator, while not shown in the diagrams, laterally oscillates the

plunger 210 by changing the rotational movement of a motor to a linear oscillating movement by means of a cam. Thus, the grinding abrasive film 162 slides laterally back and forth against the surface of a work piece (w) in order to grind it.

[73] The vertical actuator 170 moves the plunger 210 vertically to selectively put the grinding abrasive film 162 in contact with the work piece (w), by means of a hydraulic cylinder (which is a device that changes hydraulic pressure to linear, mechanical energy). Thus, the upward and downward movement of the hydraulic cylinder prompts the plunger bracket 172 to move vertically, so that the plunger 210 installed below the plunger bracket 172 moves vertically, enabling selective contacting of the grinding abrasive film 162 to the surface of the work piece (w).

[74] A liquid coolant pipe 180 for supplying liquid coolant is provided on the right sides of the ultraprecision grinders 160 and 160'. A liquid coolant motor 182 for forcefully discharging liquid coolant is installed above the liquid coolant pipe 180; and a liquid coolant nozzle 184, for guiding the discharging of liquid coolant towards the surface of the work piece (w), is connected below the liquid coolant pipe 180.

[75] The ultraprecision grinders 160 and 160' are selectively operated according to whether a work piece (w) has been inserted. That is, they are selectively operated according to whether a work piece (w) is sensed to have been inserted by the operating sensors 134a, 134b, 134c and 134d (to be described below). The operation thereof will hereinafter be described in further detail.

[76] A control box 190 is installed on one side of the ultraprecision grinders 160 and

160'. More specifically, a cube-shaped control box 190 is installed to be spaced a predetermined distance from the ultraprecision grinders 160 and 160', and is supported by a control box support 192 that is bent to extend from the top of the grinder support stand 150. A plurality of control components are installed within the control box 190 to control the operation of the ultraprecision grinders 160 and 160', the grinder rollers 130, and various other components. A plurality of control buttons 194 are formed at the front of the control box 190 so that a user can set the operation of the auto-grinder.

[77] Figs. 6a through Fig. 6c are plan and side views of a table rotating member and a roller supporting member according to an embodiment of the present invention, showing a pair of grinder rollers that are supported. Specifically, Fig. 6a is a plan view showing a pair of grinder rollers installed on top of the table rotating member 110 and the roller supporting member 120, and Figs. 6b and 6c are side perspectives thereof.

[78] Referring to Figs. 6a through 6c, the table rotating member 110 is formed with a rotatable turntable 112 that supports the grinder rollers 130, and an axis 114 formed at the center of the turntable 112 to provide a center of rotation for the turntable 112.

[79] In further detail, the turntable 112 is a roughly rectangular plate that is disposed on the top surface of the support die 100 to be capable of sliding. The axis 114, which may be a locating pin, is installed at the center of the turntable 112. That is, pin receptacles 114' are formed in opposition at the bottom of the turntable 112 and at the top of the support die 100 for inserting the axis 114 into, so that the turntable 112 may rotate on the axis 114. Thus, the turntable 112 can rotate around the axis 114 above the support die 100 in a clockwise or counter-clockwise direction.

[80] Ruled markings may be formed on the top periphery of the turntable 112. That is, ruled markings may be formed on the top periphery of the turntable 112 to visually ascertain the amount of turntable rotation, when the turntable 112 is rotated around the axis 114. Conversely, of course, the ruled markings for checking the amount of turntable 112 rotation may be formed on a surface other than the turntable 112 within a visible region around the rotating turntable 112.

[81] A plurality of clamps 116 are formed around the periphery of the turntable 112. The clamps 116, for fastening the turntable 112, are formed in mutually-facing " p" and "-| " shapes, as shown in Fig. 6b. That is, the clamps are respectively installed on the four corners of the rectangular turntable 112 to fasten the turntable 112 to the support die 100. [82] The clamps 116 fasten to the top surface of the support die 100 through fastening screws 116'. Therefore, the fastening screws 116' pass vertically through the clamps 116, and fasten to the top surface of the turntable 112. As shown in Fig. 6b, an end of the clamp 116 presses against the turntable 112 to fasten the turntable 112.

[83] A supporting plate 118 and a roller supporting member 120 are formed above the table rotating member 110. That is, a supporting plate 118, that is rectangular and has a smaller surface area than the turntable 112, is detachably mounted on the turntable 112, and a roller supporting member 120 is further mounted on top of the supporting plate 118.

[84] The roller supporting member 120 supports the respective ends of the grinder roller

130 and includes a support bracket 122, a roller bracket 124 that supports both ends of the grinder roller 130 so that it is capable of rotating, and a controlling plate 126 formed between the support bracket 122 and the roller bracket 124.

[85] The support bracket 122 is provided in plurality along each bracket, which extend parallelly and at a predetermined distance to each other from below the inner mutually- facing ends to the outer ends of the respective controlling plates 126, and are symmetrical to support brackets 122 of the opposite controlling plate 126.

[86] In further detail, as shown in Fig. 6c, the side view of the support bracket 122 is a roughly triangular plate with a predetermined thickness. The top surface thereof includes an inclined mounting surface 122' that is cut to be inclined at a predetermined angle. Therefore, the inclined mounting surfaces 122' of the support bracket 122, which have the controlling plates 126 mounted thereon, are installed so that they face each other.

[87] The controlling plate 126 is detachably mounted on the inclined mounting surface

122' of the support bracket 122. The controlling plate 126 is a plate of a predetermined thickness and extends from left to right. The left and right extension of the controlling plate 126 may overshoot the left and right parameters of the support bracket 122. A ruled marker may be formed on top of the control plate 126 from the left to the right, so that a user may input a more accurate operational setting by referring to the ruled marker during the rotation of the grinder roller 130.

[88] The roller bracket 124 is installed on top of the controlling plate 126. The roller bracket 124 may be permanently mounted to the top of the controlling plate 126, and includes a mounting portion 124' formed of a flat plate for mounting to the controlling plate 126 and a roller support 124" protruding from both ends of the mounting portion 124'. The mounting portion 124' is elongated from left to right and mounted to the top surface of the controlling plate 126. The roller support 124" rotatably supports both ends of a grinder roller 130. A bearing is provided at each end of the grinder rollers 130 to allow smooth rotation of the grinder rollers 130 while they are supported on both ends by the roller support 124".

[89] The mounting portion 124' is mounted to the top surface of the controlling plate 126 so that it is capable of sliding. That is, the roller bracket 124 is installed on the top of the controlling plate 126 so that it can rotate. Accordingly, the mounting portion 124' of the roller bracket 124 has a rotating pin 128 installed at its center. The upper and lower portions of the rotating pin 128 are respectively inserted and installed in the mounting portion 124' of the roller bracket 124 and the controlling plate 126, so that it functions as the rotational axis of the roller bracket 124.

[90] A plurality of operating sensors 134a, 134b, 134c and 134d are installed apart from one another between the pair of grinder rollers 130. The operating sensors 134a, 134b, 134c and 134d sense whether a work piece (w) is inserted (or rather, placed on surfaces) between a pair of grinder rollers 130. That is, the sensors sense whether a work piece (w) has been placed on top between a pair of grinder rollers 130.

[91] The operating sensors 134a, 134b, 134c and 134d are divided in two pairs to be respectively installed on each of the ultraprecision grinders 160 and 160'. That is, the left-side ultraprecision grinder 160 has a pair of operating sensors 134a and 134b installed therebelow, and the right-side ultraprecision grinder 160' has a pair of operating sensors 134c and 134d installed therebelow.

[92] More specifically, a first operating sensor 134a and a second operating sensor 134b are installed a predetermined distance apart below the left-side ultraprecision grinder 160, and a third operating sensor 134c and a fourth operating sensor 134d are installed a predetermined distance apart below the right-side ultraprecision grinder 160'.

[93] Therefore, the ultraprecision grinder 160 or 160', respectively disposed above the pair of operating sensors 134a and 134b or 134c and 134d, operates only when both sensors in the relevant pair sense the presence of an inserted work piece (w). That is, when both the first and second operating sensors 134a and 134b sense the presence of an inserted work piece (w), the left-side ultraprecision grinder 160 operates to grind the work piece (w).

[94] Furthermore, when only one of the first and second operating sensors 134a and

134b senses the presence of an inserted work piece (w), the left-side ultraprecision grinder 160 does not operate. Therefore, when the left-side ultraprecision grinder 160 operates because both the first and second operating sensors 134a and 134b sense the presence of an inserted work piece (w), and the work piece (w) moves to the right so that the first operating sensor 134a no longer senses the presence of the work piece (w), the left-side ultraprecision grinder 160 ceases to operate.

[95] Similarly, the right-side ultraprecision grinder 160' operates only when both the third and fourth operating sensors 134c and 134d sense the presence of a work piece.

[96] The operating sensors 134a, 134b, 134c and 134d may be rod-shaped and supported at their bases by a sensor support 134'. The operating sensors 134a, 134b, 134c and 134d are attached to the sensor support 134' by a hinge to pivot to the left and right. Therefore, when a work piece (w) contacts the top of an operating sensor 134a, 134b, 134c and 134d, the latter pivots on the hinge 134' at the bottom, thus sensing the presence of an inserted work piece (w).

[97] Of course, the structure of the operating sensors 134a, 134b, 134c and 134d and the sensing method of the presence of a work piece (w) may take various other forms. That is, an infrared sensor for sensing the presence and movement of a work piece (w) is among various other detecting methods.

[98] Fig. 7 is an exploded perspective view of the structure of a plunger 210 and grinder heads 200 according to an embodiment of the present invention. Referring to Fig. 7, the plunger 210 is formed of a flat plate of a predetermined thickness, and includes a plurality of fastening holes 212 (for inserting fastening members) formed from front to back at the upper portion thereof. The fastening members (not shown) pass through the fastening holes 212 and fasten to a plunger bracket 172, to fix the plunger 210 to the plunger bracket 172.

[99] A plurality of protruding head supporters 214 is formed to protrude from the bottom of the plunger 210. That is, to rotatably install a plurality of grinder heads 200 at the bottom of the plunger 210, five head supporters 214 for supporting both ends of a grinder head 200 are formed to protrude downward from the bottom of the plunger 210, as shown in Fig. 7.

[100] The head supporter 214 has a bearing hole 214' formed through it. Specifically, each head supporter has a bearing hole 214' formed through it from left to right. The bearing hole 214', is for insertingly installing a bearing 230 (to be described below) that supports both ends of a grinder head 200.

[101] A bracket mounting portion 216 is formed to recess into the left and right lower portions of the plunger 210. The bracket mounting portion 216 formed to recess respectively into the left and right sides of the plunger 210 are symmetrical to each other. That is, the bracket mounting portion 216 formed in the left lower side of the plunger 210 is formed to recess a predetermined amount towards the right, and the bracket mounting portion 216 formed in the right lower side of the plunger 210 is formed to recess a predetermined amount towards the left. Also, a screw fastening hole 216' is formed in the bracket mounting portion 216 for installing a fastening bracket 220 to be described below.

[102] A fastening bracket 220 is fastened to the bracket mounting portion 216. The

fastening bracket 220 is formed to reflect one end of the bracket mounting portion 216 to fasten firmly against a surface (left or right surface) of the bracket mounting portion 216. [103] A screw through-hole 222 is formed through the fastening bracket 220 from left to right. The screw through-hole 222 is a portion through which a fastening screw 224 passes. After a fastening screw 224 passes through the screw through-hole 222 on the fastening bracket 220, it fastens to the screw fastening hole 216' on the bracket mounting portion 216 to prevent the dislodging of the bearing (to be described below).

[104] A plurality of (four) grinder heads 200 are installed between the plurality of head supporters 214. The reason for installing the grinder heads 200 in plurality is to smoothly guide the grinding abrasive film 162 for enhanced grinding performance. That is, when compared to a grinder head 200 that extends in a single piece from the left to right, the use of multiple headers and grinding abrasive films 162 enables a better response to differing levels of tension on the films from the left to the right. That is, the pressure exerted on the grinding abrasive films 162 at the four respective grinder heads 200 is effectively dispersed, so that the contact between the grinding abrasive films 162 and the work piece (w) is even (allowing contact at all points) and grinding effectiveness increases.

[105] The grinder head 200 has a cylindrical shape, as shown in Fig. 7, and may have a rod-shaped axial protrusion 202 protruding from the left and right sides thereof. The axial protrusion 202 functions as a rotating axis for the grinder head 200, and inserts into the bearing 230 which will be described below.

[106] A bearing 230 is inserted into the bearing hole 214' of the head supporter 214. The bearing 230 is a commonly-used mechanical component that fixes a physical rotating axis in an unvarying position while supporting the laden and unladen weight of the axis and allowing the axis to rotate. Thus, description thereof will be omitted herefrom.

[107] The axial protrusion 202 of the grinder head 200 is insertedly fixed in the central hole 232 of the bearing 230. That is, the axial protrusion 202 is force-fitted into the central hole 232 forming the intrados of the bearing 230. Thus, the grinder head 200 can rotate freely.

[108] A grinding abrasive film 162 moves around the grinder header 200. Specifically, grinding abrasive film 162, that is supplied from a feeding roll 164, is guided smoothly towards a take-up roll 166 by the rotating grinder head 200.

[109] Fig. 8 is a sectional view of a grinder head according to an embodiment of the

present invention. Referring to Fig. 8, a cushion layer 204 is formed on the surface of the cylindrical grinder head 200. The cushion layer 204, for effectively absorbing external shocks or pressure exerted on the grinding abrasive film 162, is formed of a non-metallic or elastic material, which may be urethane rubber.

[110] When a cushion layer 204 of urethane rubber is formed on the surface of the

grinding head 200, the grinder head 200 can more effectively absorb external shocks or force (pressure) exerted on the grinding abrasive film 162 than if it were made of a metallic material.

[I l l] Although not shown in the diagrams, inserting and discharging devices may be further installed at the left and right ends of the auto-grinder to automatically insert and discharge a work piece (w). That is, an inserting device may be provided on the left side of the auto-grinder in order to automatically insert work pieces (w) one at a time, and a discharging device may be provided on the right side of the auto-grinder in order to automatically discharge the work pieces (w) processed by the auto-grinder and load them on a receiving member one at a time.

[112] Below, the operation and controlling method of the above-described auto-grinder will be described.

[113] First, a user inputs operational settings into the auto-grinder. Here, the user sets the positions of the grinder rollers 130 according to the size of the work piece(s) (w) to be inserted.

[114] More specifically, as shown in Fig. 6c, because a work piece (w) is inserted

between a pair of grinder rollers 130 to be processed and must move automatically toward the right (as shown in Fig. 3) at the same time, the setting must be done so that a work piece (w) can be placed at an appropriate location between the pair of grinder rollers 130. That is, if the gap between the pair of grinder rollers 130 is larger than the diameter of the work piece (w), the work piece (w) cannot be placed between the grinder rollers 130 (as shown in Fig. 6c) and will fall through the gap. On the other hand, if the gap between the pair of grinder rollers 130 is excessively smaller than the diameter of the work piece (w), the work piece (w) will ride on top of the two grinder rollers 130, and the friction between the work piece (w) and the grinder rollers 130 will be insufficient. Thus, the rotation of the work piece (w) will be uneven, and its automatic movement towards the right will be disrupted.

[115] The user also adjusts the inclining angles of the pair of grinder rollers 130. That is, in order to move a work piece (w) in one direction (the right), when the grinder rollers 130 in a pair are inclined in mutually opposite directions, the speed in which the work piece (w) moves is determined by the incline angle of the two grinder rollers 130.

[116] In still further detail, the surface roughness of a work piece (w) after it is processed is determined by the speed (V) in which it moves and its rate of rotation (n). That is, the slower the speed (V) that the work piece (w) moves, and the faster it rotates (n), the more polished it will be.

[117] Also, the speed (V) and rate of rotation (n) of the work piece (w) is affected by the slope (intermediate angle, α) and the rotating speed (N) of a pair of grinder rollers 130. That is, the moving speed (V) of the work piece (w) depends the angle (α) formed by the pair of grinder rollers 130, and the rotating speed (n) of the work piece (w) is proportional to the rotating speed (N) of the grinder rollers 130. [118] The moving speed (V) of the work piece (w) can be described by the following equation, where (d) is the outer diameter of the grinder roller.

[119] V = πdN(sin α)/1000

[120] When a user adjusts the intersecting angle formed by the pair of grinder rollers 130 to achieve a desired surface finish for a work piece (w), the respective grinder rollers 130 are moved in the opposite direction.

[121] Referring to Figs. 9a and 9b, an example of a pair of grinder rollers 130 that is turned clockwise (when viewed from the top) is discussed.

[122] Here, the roller bracket 124 is turned on the rotating pin 128 of the mounting

portion 124'. Thus, the right ends of the grinder rollers 130 are disposed as shown in Fig. 9b. Specifically, the right portion of the rear roller brackets 124 supporting a grinder roller 130 slides towards the bottom of the rear controlling plate 126, and conversely, the right portion of the front roller brackets 124 slides towards the top of the front controlling plate 126. Here, the right end of the work piece (w) that rises between the pair of grinder rollers 130 moves to the left in Fig. 9a.

[123] Similarly, although not shown in the diagrams, the left portion of the of the pair of roller brackets 124 moves in the opposite direction to the right portion of the roller brackets 124 when seen in Fig. 9a. That is, the left portion of the rear roller bracket 124 moves downward, and the left portion of the front roller bracket 124 moves upward.

[124] The pair of grinder rollers 130 that has moved is shown in a plan view in Fig. 9b.

As shown, the pair of roller brackets 124 rotated clockwise on the rotating pins 128, so that the pair of grinder rollers 130 and the work piece (w) are twisted, and the entire assembly is turned in a clockwise direction.

[125] Thus, the grinder rollers 130 and the work piece (w) have turned collectively

clockwise as shown by ® in Fig. 9b, whereupon the angle of rotation is V. That is, because the pair of grinder rollers 130 and the work piece (w) have rotated by an angle V from their initial position shown in Fig. 6a, the pair of grinder rollers 130 and the work piece (w) are not parallel to the plungers 210 of the ultraprecision grinders 160 and 160'. When this happens, the processing of the work piece (w) by the ultra- precision grinders 160 and 160' is improperly conducted.

[126] Accordingly, a user must readjust the direction of the grinder rollers 130 to be

parallel to the plungers 210 of the ultraprecision grinders 160 and 160'. Here, the table rotating member 110 can be used to collectively rotate the components installed on top of the support die 100.

[127] In further detail, the turntable 112, that is rotatably installed on top of the support die 100, is rotated. Here, the fastening screws 116' fastening the turntable 112 are loosened so that the clamps 116 are disengaged. Therefore the turntable 112 can be rotated around the pin 114, and the turntable 112 is rotated counter-clockwise as shown by © in Fig. 9b.

[128] Through this process, when the pair of grinder rollers 130 and the work piece (w) become parallel to the plungers 210 of the ultraprecision grinders 160 and 160', the turntable is fastened to the support die 100 by using the clamps 116. In this way, the setting of the grinder rollers 130 is completed.

[129] Subsequently, when an outer power source is applied to the auto-grinder, a user can manipulate the control buttons 194 on the control box 190 to input operational settings for the auto-grinder. While the auto-grinder is set to operate automatically, it can, of course, be set for manual operation to operate in stages.

[130] The processing of a work piece (w) by the auto-grinder involves a plurality of steps outlined in Fig. 10. That is, the work piece (w) is first supplied by being placed on top of a pair of grinder rollers 130 in step S300. The work piece (w) that has been supplied on top of the pair of grinder rollers 130 undergoes a work piece conveying stage in step S310, a detecting stage for detecting if the work piece (w) is supplied and conveyed in step S320, a stage for supplying liquid coolant to the surface of the work piece (w) in step S330, a grinding stage in step S340 in which the ultraprecision grinders 160 and 160' move to the location of the work piece (w) and grind the surface of the work piece (w), a discharging detecting stage in S350 for detecting that the work piece (w) is discharged, a liquid coolant blocking stage in step S360 for blocking the supply of liquid coolant, and a returning stage for returning the ultraprecision grinders 160 and 160' to their original positions.

[131] The supplying of the work piece in step S300 is a loading of a work piece (w) longitudinally between a pair of grinder rollers 130. That is, the loading of a work piece (w) at the left side between the pair of grinder rollers 130 may be done manually by a user or automatically through a loading device (described above, but not shown in the diagrams).

[132] The conveying stage of the work piece in step S310 is the conveying of the work piece (w) lengthwise along the grinder rollers 130. The rotation of the pair of grinder rollers 130 prompts the work piece (w) to rotate as well as move from the left to the right. That is, the roller motor 140 imparts rotational force, which is transferred through the drive chain 142 to the pair of grinder rollers 130. The grinder rollers 130 are installed to intersect at a predetermined angle and rotate to prompt the work piece (w) to rotate and simultaneously move from the left to the right.

[133] Here, the rotating direction of the grinder rollers 130 and that of the work piece (w) are opposite. That is, if, for example, the grinder rollers 130 rotate in a counterclockwise direction, the work piece (w), that contacts the pair of grinder rollers 130, rotates in a clockwise direction. Conversely, when the grinder rollers 130 rotate in a clockwise direction, the work piece (w) rotates in a counter-clockwise direction. [134] The detecting stage in step S320 is when a work piece is sensed by both operating sensors 134a, 134b, 134c and 134d in a pair. When a work piece (w) is supplied on top of a pair of grinder rollers 130, this stage detects whether it has reached a position in which grinding is performed (after being conveyed toward the right). That is, it is sensed whether the work piece (w) is in a position to contact an ultraprecision grinder 160 or 160' in order to begin processing (grinding).

[135] In more detail, the work piece (w) is loaded onto a pair of grinder rollers 130 and is conveyed to the right, so that it interferes with the operating sensors 134a, 134b, 134c and 134d. That is, the movement towards the right of the work piece (w) prompts it to interfere with the first operating sensor 134a, causing it to pivot, so that a control unit (not shown) is informed that the leading end (right end) of the work piece (w) has moved to the location of the first operating sensor 134a.

[136] Subsequently, the work piece (w) continues to be conveyed, and interferes with the second operating sensor 134b that is spaced a predetermined distance apart from the first operating sensor 134a. Then, the second operating sensor 134b pivots to detect the location of the work piece (w). Thus, the control unit (not shown) is informed that the leading edge (right edge) of the work piece (w) has reached the location of the second operating sensor 134b. This is the point when the processing of the work piece (w) is begun by the ultraprecision grinders 160 and 160'.

[137] When the work piece (w) thus interferes with both the first and second operating sensors 134a and 134b, the control unit (not shown) is informed of the inputted work piece (w) and issues a command to begin operation of the left- side ultraprecision grinder 160. Accordingly, the supplying of liquid coolant in step S330 and the grinding in step S340 are implemented.

[138] The supplying of liquid coolant in step S330 is the supplying of liquid coolant on the surfaces of the work piece (w) and the grinding abrasive film 162 to cool the two articles. Here, a liquid coolant motor 182 operates to draw liquid coolant from an external source through a liquid coolant pipe 180, and spray the liquid coolant onto the surface of the work piece (w) through a liquid coolant nozzle 184.

[139] The grinding in step S340 processes the surface of the work piece (w) with the grinding abrasive film 162. Specifically, when the work piece (w) is detected as inputted above, the control unit sends a processing command, and the left-side ultra- precision grinder 160 begins processing the work piece (w). Here, the ultraprecision grinder 160 descends to grind the surface of the work piece (w) with the grinding abrasive film 162.

[140] The grinding in step S340 includes an adjusting of the tension for the grinding abrasive film 162 to a suitable level in step S342, an oscillating stage in step S344 to oscillate the grinding abrasive film 162 laterally, and a contacting stage in step S346 for contacting the oscillating grinding abrasive film 162 to the surface of the work piece. Each of these steps are performed simultaneously or sequentially.

[141] In step S342, the tension of the grinding abrasive film that extends from the feeding roll 164 to the supporting rollers 168, the plunger 210, and the take-up roll 166 is adjusted by a feeding motor and a take-up motor (not shown) provided respectively at a side of the feeding roll 164 and the take-up roll 166 to impart rotational force to the two rolls 164 and 166.

[142] The oscillating in step S344 uses the lateral oscillator (described above) to oscillate the plunger 210 and the grinder head 200 to the left and right. This is achieved through a cam built into the ultraprecision grinders 160 and 160'.

[143] The contacting in step S346 moves the plunger 210 downward to contact the

grinding abrasive film 162 around the tip of the grinder head 200 with the work piece (w). The plunger 210 is moved by the operation of a hydraulic cylinder of the vertical actuator 170. Specifically, when the plunger 210 installed on the plunger bracket 174 is moved downward by the vertical actuator 170, the grinding abrasive film 162 supported by the grinder head 200 below the plunger 210 contacts the surface of the work piece (w), which is moved by the grinder rollers 130.

[144] In the above process, when the grinding abrasive film 162 contacts the surface of the work piece (w), grinding is performed. That is, the grinding abrasive film 162 contacts the outer surface of the grinder head 200 and slowly turns. Here, the grinding abrasive film 162 contacts and grinds the surface of the work piece (w).

[145] Additionally, the metal chips that are removed from the work piece (w) or the liquid coolant sprayed from the liquid coolant nozzle 184 onto the work piece (w) is guided by the dispersing grooves 122 formed on the grinder rollers 130.

[146] In the above process, the work piece (w) is processed by the grinding abrasive film

162, and gradually moves to the right. After the grinding in step S340, a detecting of discharging is performed in step S350.

[147] The detecting of discharging in step S350 is a stage where one of a pair of operating sensors 134a, 134b, 134c and 134d ceases to detect the presence of a work piece (w) after the latter has been in contact with both sensors in the pair. The discharging of the work piece (w) is detected when it moves to the right. That is, when the work piece (w) departs from a workable position in which it can be processed by an ultraprecision grinder 160 or 160', the instant when the work piece (w) is no longer detected by one of a pair of operating sensors 134a, 134b, 134c and 134d signifies that the ultra- precision grinder 160 or 160' should cease operating.

[148] In more detail, the work piece (w), that is processed by the left-side ultraprecision grinder 160, gradually moves towards the right. When the work piece (w) departs from the first operating sensor 134a at the left, the control unit (not shown) is notified, and the operation of the left-side ultraprecision grinder 160 is stopped. Thus, grinding is completed.

[149] Likewise, only when both operating sensors 134a, 134b, 134c and 134d in a pair detect the presence of a work piece (w), does the ultraprecision grinder 160 or 160' perform grinding, for a more precise grinding, an increased surface finish of the work piece (w), and a reduction in wear on the grinding abrasive film 162.

[150] For example, if the left-side ultraprecision grinder 160 begins operating before both operating sensors 134a, 134b, 134c and 134d in one pair detect the presence of a work piece (w) and only the first operating sensor 134a detects the work piece (w), the work piece (w) may be difficult to maintain in a horizontal disposition, which may twist the grinder head 200. When this happens, the surface finish of the work piece (w) that is ground is uneven, and an uneven wear on the grinding abrasive film 162 results due to the twisted grinder head.

[151] When the grinding in step S340 is completed, a blocking of liquid coolant is

performed in step S360, and a returning process is performed in step S370. Of course, the above steps S360 and S370 may be performed sequentially and not simultaneously.

[152] The blocking of the liquid coolant in step S360 blocks the spraying of liquid coolant onto the surface of a work piece (w). Here, the liquid coolant motor 182 ceases operating to block the supply of liquid coolant through the liquid coolant pipe 180.

[153] The returning process in step S370 ceases the operation of the left-side ultra- precision grinder 160, and at the same time, returns it to its original position. Accordingly, the left-side ultraprecision grinder 160 is moved back upward by the vertical actuator 170, so that the grinding abrasive film 162 is removed from the surface of the work piece (w). Also, the oscillating in step S344 is stopped, and the tension applied to the grinding abrasive film 162 is removed.

[154] Because the ultraprecision grinders 160 and 160' according to the present invention are provided together as a pair, the above processes are repeated for the second ultra- precision grinder. That is, after the work piece (w) is processed according to the steps described above, the work piece (w) continues moving toward the right by means of the pair of grinder rollers 130, and undergoes grinding performed by the right-side ultraprecision grinder 160'.

[155] Accordingly, the steps from the detecting of work piece insertion in step (S320) through to the returning of the ultraprecision grinder in step (S370) are repeated. That is, when both the third and fourth operating sensors 134c and 134d detect the presence of the work piece (w), the right-side ultraprecision grinder 160' processes the work piece (w). When the work piece (w) disengages from the third operating sensor 134c, the processing performed by the right-side ultraprecision grinder 160' ceases, and the right-side ultraprecision grinder 160' returns to its original position. [156] The work piece (w) that is sequentially processed by the left-side and right-side ul- traprecision grinders 160 and 160' continues to be conveyed to the right by the pair of grinder rollers 130. Here, the work piece (w) is removed from the auto-grinder and transported to another location by means of a separate discharging device (not shown) or manually.

[157] While the present invention has been described and illustrated herein with reference to the preferred embodiments thereof, it will be apparent to those skilled in the art that various modifications and variations can be made therein without departing from the spirit and scope of the invention. Thus, it is intended that the present invention covers the modifications and variations of this invention that come within the scope of the appended claims and their equivalents.

[158]

Industrial Applicability

[159] The auto-grinder according to the present invention and the operating method

thereof allows for increased precision during processing, for a high industrial applicability.

[160]

Claims

[1] An auto-grinder comprising:

a film-type ultraprecision grinder including a grinding abrasive film for contacting and grinding a surface of a work piece, a grinder head for guiding the grinding abrasive film to contact the surface of the work piece, and a plunger for supporting the grinder head;

a grinder roller installed as a pair to mutually intersect at a predetermined angle at a side of the ultraprecision grinder, having an outer diameter that decreases from both ends toward a middle thereof, and for simultaneously rotating the work piece and conveying the work piece to one end thereof;

an operating sensor for sensing an insertion of the work piece;

a roller supporting member for supporting both respective ends of the grinder roller; and

a table rotating member rotatably installed on a top of a supporting die that supports a plurality of components, the table rotating member supporting the pair of grinder rollers and the roller supporting member, wherein

the ultraprecision grinder selectively operates according to whether the operating sensor senses that the work piece has been inserted, and the grinder head is rotatably installed on an end of the plunger.

[2] The auto-grinder according to claim 1, wherein the ultraprecision grinder is provided in duplicate or more and installed along a common line next to one another.

[3] The auto-grinder according to claim 1, wherein the ultraprecision grinder further includes:

a feeding roller for supplying the grinding abrasive film;

a take-up roller installed at a side of the feeding roller, for taking up the grinding abrasive film that has been used for grinding the work piece;

a plurality of supporting rollers for supporting the grinding abrasive film between the feeding roller and the take-up roller;

a vertical actuator installed at a side of the plunger for selectively engaging the grinding abrasive film to the surface of the work piece; and

a lateral oscillator installed at a side of the plunger for oscillating the plunger laterally over a predetermined parameter.

[4] The auto-grinder according to any one of claims 1 through 3, wherein the table rotating member includes:

a turntable rotatably installed for supporting the grinder roller;

a pin provided at a central portion of the turntable as a center of rotation for the turntable.

[5] The auto-grinder according to claim 4, wherein the roller supporting member includes:

a support bracket provided above the turntable for supporting the grinder roller; a roller bracket for rotatably supporting both ends of the grinder roller; and a controlling plate provided between the support bracket and the roller bracket and installed to be capable of rotating on a surface of the support bracket.

[6] The auto-grinder according to claim 5, wherein the controlling plate is installed to be capable of rotating around a rotating pin formed in a central portion thereof.

[7] The auto-grinder according to claim 1, wherein the grinder roller includes a

plurality of dispersing grooves formed on an outer surface thereof for guiding and dispersing residual material formed during grinding.

[8] The auto-grinder according to claim 1, wherein the grinder head is provided in plurality, is cylindrical, and has a bearing installed on either end thereof.

[9] The auto-grinder according to claim 8, wherein the grinder head further has a cushioning layer of urethane rubber formed on a surface thereof.

[10] The auto-grinder according to claim 1, wherein the operating sensor is disposed in a space formed by the pair of grinder rollers, and is provided in plurality.

[11] The auto-grinder according to claim 10, wherein the operating sensor is installed in a pair below each ultraprecision grinder.

[12] The auto-grinder according to claim 11, wherein the ultraprecision grinder

operates only when both of the installed pair of operating sensors sense an insertion of the work piece.

[13] A controlling method for an auto-grinder comprising:

supplying a work piece on top of a pair of grinder rollers;

conveying the supplied work piece in one direction;

detecting the supplying and conveying of the work piece;

supplying liquid coolant to a surface of the work piece;

conveying the work piece to a processing location and grinding the surface of the work piece with an ultraprecision grinder;

detecting a conveying and discharging of the work piece;

blocking the supplying of liquid coolant; and

stopping a grinding process and returning the ultraprecision grinder to an original position.

[14] The controlling method according to claim 13, wherein the grinding of the

surface of the work piece includes operations of:

adjusting a tension of a grinding abrasive film to have a predetermined amount of tension; oscillating the grinding abrasive film in left and right directions; contacting the grinding abrasive film to the surface of the work piece; and grinding the work piece using the grinding abrasive film, wherein the operations are simultaneously or sequentially performed.

[15] The controlling method according to claim 13 or 14, wherein the detecting of the supplying of the work piece includes detecting the work piece with both of a pair of operating sensors contacting the work piece.

[16] The controlling method according to claim 15, wherein the detecting of the

discharging of the work piece includes detecting the work piece with only one of the pair of operating sensors contacting the work piece.

[17] The controlling method according to claim 13, wherein the supplying of liquid coolant to and the grinding of the surface of the work piece are performed simultaneously.

[18] The controlling method according to claim 13, wherein the blocking of the liquid coolant and the returning of the ultraprecision grinder to the original position are performed simultaneously.