KR20160054860A - Hool device for apc of machine tool - Google Patents

Abstract

The present invention relates to a hook device for transporting a pallet of a machine tool, and more specifically, to a hook device for transporting a pallet of a machine tool which is applied to an automatic pallet change (APC) system for automatically replacing a pallet which operates as a workpiece support of a machine tool to hook the pallet to transport the pallet to a desired location. The hook device for transporting a pallet of a machine tool uses a cam body having a multi-stage cam processing surface and a multi-stage locking groove, a first spring pin for guiding angular rotation of the cam body, and a second spring pin for limiting reverse angular rotation of the cam body to rotate a hook body to hook and lock the pallet when moving forwards. When moving backwards, the hook body is not rotated and the pallet is maintained in a locked state to easily transport the pallet to a desired location while the hook body pulls the pallet.

Description

Technical Field [0001] The present invention relates to a hook device for transferring a pallet of a machine tool,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a hook device for transferring a pallet of a machine tool, and more particularly to an automatic pallet changer (APC) system for automatically replacing a pallet serving as a workpiece support of a machine tool, The present invention relates to a hook device for transferring a pallet of a machine tool.

In general, machine tools are equipped with an automatic tool changer (ATC) which automatically changes the tool specified in the machining order, and an automatic pallet exchange (hereinafter referred to as APC) system for automatically changing the pallet serving as a pedestal of the workpiece Respectively.

The APC (AUTO PALLET CHANGE) refers to a system for automatically replacing a pallet, which serves as a pedestal for a workpiece in a machine tool and fixes the workpiece in motion.

1 is a plan view of an APC system of a machine tool.

In Fig. 1, reference numeral 10 denotes a palette.

The pallet 10 includes a first pallet 11, a second pallet 12, a third pallet 13, and the like disposed at different positions according to the processing position of the machine tool.

At this time, each of the first pallet 11, the second pallet 12, and the third pallet 13 is fixedly arranged to support the workpiece at each machining position of the machine tool.

In order to send the first pallet 11 to the second pallet 12 position in accordance with the machining order of the workpieces during the machining operation of the machine tool, the second pallet 12 must be sent to the third pallet 13 position, Should be replaced.

A system for automatically transferring each pallet to a desired machining position is referred to as an APC system. The APC system includes a hook device for moving a pallet to a desired position.

2, the hook device 20 is mounted on an APC arm 14 that can be moved forward and backward by a transfer device (not shown) to hang the pallet 10.

Accordingly, after the hook portion of the hook device 20 is hooked on the pallet 10, by pulling or pushing the pallet in the forward and backward movement of the APC arm 14 moved by the transfer device, do.

Hereinafter, a conventional pallet transporting hook device will be described.

3 is a cross-sectional view of a conventional pallet transporting hook device.

In Fig. 3, reference numeral 21 designates the hook body of the hook device 20.

The hook body 21 is rotatably mounted up and down by a hinge shaft 18 in a housing 16 fixed on an APC arm 14.

A hook 22 for hooking the pallet 10 is formed at the front end of the hook body 21 and a slant surface 24 is formed at the bottom of the rear end of the hinge shaft 18 for vertical rotation And a spring support groove 26 is formed on the upper surface between the hook 22 and the hinge shaft 18. [

A spring 28 is mounted between the spring support pin 17 formed on the housing 16 and the spring support groove 26.

Particularly, an air cylinder 30 for pressing the rear end of the hook body 21 is disposed at the upper end of the rear end of the hook body 21.

Further, although the conventional hook device is not shown, it further includes a pallet position detecting sensor for controlling the operating timing of the air cylinder 30, a valve for opening and closing the air, and the like.

Therefore, when the APC arm 14 is advanced to the pallet position by the transfer device, the hook device mounted on the APC arm 14 is advanced to the pallet position, at which time the air cylinder 30 is operated.

The air pressure of the air cylinder 30 acts on the rear end of the hook body 21 so that the rear end of the hook body 21 descends about the hinge shaft 18 and the hook 22 of the front end portion So that the spring 28 is in a compressed state.

When the hook 22 is transferred to the upper side of the pallet 10, the operation of the air cylinder 30 is stopped to release the air pressure acting on the rear end of the hook body 21, The front end portion of the hook body 21 is lowered to its original position and the rear end portion is raised and lowered to its original position.

The hook 22 formed on the front end of the hook body 21 is hooked on the pallet 10 so that the hook 22 can pull or push the pallet 10.

Accordingly, the pallet 10, to which the hook 22 of the hook body 21 is hooked, can be transported to a desired position by moving the APC arm 14 back and forth by the transfer device.

However, the above-described conventional pallet transporting hook device has the following disadvantages.

First, since an expensive air cylinder is used for ascending and descending the hook body, and an air supply source is used, and a sensor and a valve for controlling the operation timing of the air cylinder are additionally required, There is a disadvantage that it is complicated and raises manufacturing and assembly costs.

Second, there is a disadvantage in that the assembling workability is greatly reduced due to the necessity of a wire processing operation of sensors and valves including an air cylinder, and maintenance and maintenance work are difficult.

SUMMARY OF THE INVENTION The present invention has been accomplished in order to solve the above-mentioned problems, and it is an object of the present invention to provide a cam body having a multi-stage cam working surface and a multi-stage locking groove, a first spring pin for rotation guidance of the cam body, By using the second spring pin for restricting the rotation, the hook body can be locked and locked while the hook body rotates, and the hook body can be kept in a locked state without rotating the hook body during the backward movement, It is an object of the present invention to provide a hook device for transferring a pallet of a machine tool, which enables a body to be easily transported to a desired position while pulling a pallet.

According to an aspect of the present invention, there is provided an APC comprising: a housing fixed on an APC arm; a hook body having a rear end rotatably mounted on the hinge shaft and having a hook formed at a front end thereof; And an eccentric engagement protrusion eccentrically joined to one side of the hook body is integrally formed on an inner side surface of the hook body, and an outer surface of the hook body is integrally formed with an outer surface of the hook body, A cam body having a plurality of locking grooves formed at regular intervals such that the oblique face and the engaging face are perpendicular to each other to block each rotation of the body; A cam body supporting block fixedly mounted at one side of the housing and having a structure in which the rotation axis of the cam body is rotatably mounted while protecting the cam body; A cam body angular rotating device fixedly mounted at a front position where the hook can hang the pallet and rotating the cam body in the forward direction while contacting the cam working face of the cam body; A cam body rotatable interrupter disposed in the cam body supporting block along the rotation direction of the cam body to block the rotation of the cam body in the reverse direction while restricting the lock groove of the cam body; The present invention provides a hook device for transferring a pallet of a machine tool.

Particularly, a stepped space is formed in the lower portion of the outer side of the cam body supporting block, and the cam working surface of the cam body is exposed to the outside through the stepped space.

Further, each of the cam body rotation devices includes: a fixed block fixedly mounted at a front position where the hook can hang the pallet; A first spring mounted within the fixed block; The rear end portion being compressibly supported on the first spring and the front end portion being a first spring pin which is brought into close contact with the cam working surface of the cam body to rotate the cam body in the normal direction; .

In addition, the cam body angular rotation preventing device includes: a second spring that is compressibly inserted in the rear of the cam body supporting block along the rotational direction of the cam body; And a front end portion of the second spring pin is inserted into the lock groove of the cam body to block the cam body from rotating in the reverse direction; And

Preferably, a hook for supporting a hook body is further mounted between the bottom surface of the hook body and the bottom surface of the housing.

Through the above-mentioned means for solving the problems, the present invention provides the following effects.

First, a simple mechanical structure including a cam body having a multi-stage cam machined surface and multi-step locking grooves, a first spring pin for guiding each rotation of the cam body and a second spring pin for restricting the angular rotation of the cam body, By using the mechanism, the hook body can be hooked to the pallet, and the pallet can be easily transported to a desired position.

Second, the structure is simple and easy to assemble compared to a conventional hook and loop device including an air cylinder and an air supply source, including a sensor and a valve, so that manufacturing cost can be reduced, and maintenance and maintenance work can be easily performed have.

1 is a plan view of an APC system of a machine tool.
2 is a side view showing the operation principle of a hook device applied to an APC system of a machine tool,
3 is a side sectional view showing a conventional hook apparatus for transferring pallets of a machine tool,
4A and 4B are perspective views showing the external appearance of the cam body in the structure of the hook device for the pallet transfer of the machine tool according to the present invention,
5 is a partial cross-sectional perspective view showing a hook device for transferring a pallet of a machine tool according to the present invention,
FIG. 6 is a plan sectional view showing an operational flow for a pallet transporting hook device of a machine tool according to the present invention, FIG.
7 is a side cross-sectional view showing an operational flow for a pallet transporting hook device of a machine tool according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention relates to a hook device applied to an APC (AUTO PALLET CHANGE) system for automatically replacing a pallet serving as a workpiece support of a machine tool, comprising: a cam body having a multi-stage cam working surface and a multi- The pallet can be transported to a desired position through a simple mechanical mechanism including a mechanism for cutting the pallet or for blocking rotation of the pallet.

FIG. 4 is a perspective view showing the outer appearance of a cam body in the structure of a hook device for transferring pallets of a machine tool according to the present invention, and FIG. 5 is a perspective view showing a hook device for transferring pallets of a machine tool according to the present invention, Fig.

In Fig. 5, reference numeral 110 denotes a hook body.

The hook body 110 is rotatably mounted in the housing 100 fixed on the APC arm by a hinge shaft 112 and a hook 114 for hanging a pallet is integrally formed on the front end of the hook body do.

A cam body supporting block 130 is mounted on one side of the housing 100 and a cam body 120 is rotatably disposed in the cam body supporting block 130.

That is, the cam body 120 is wrapped and protected by the cam body supporting block 130, and a rotation axis formed on the outer surface of the cam body 120 is rotatably mounted on the cam body supporting block 130.

The cam body 120 rotates around the hook body 110 at a predetermined angle to rotate the hook body 110 upward or downward. The outer surface of the cam body 120 rotates about the rotation axis about the rotation axis of the hook body 110 An eccentric engaging protrusion 124 eccentrically eccentric to one side surface of the hook body 110 is integrally formed on the inner side surface of the hook body 110 and an eccentric engaging protrusion 124 integrally formed on the outer surface of the hook body 110 in a direction opposite to the hook body 110 A plurality of locking grooves 125 for blocking each rotation are formed at regular intervals.

The cam working surface 121 of the cam body 120 is formed in a structure in which a vertical surface 122 forming a plane along the axial direction of the cam body and an inclined surface 123 inclining along the radial direction are perpendicular to each other , Preferably four in total at intervals of 90 degrees along the circumferential direction of the cam body 120.

The eccentric engagement protrusions 124 of the cam body 120 are protruded in an elliptical block shape so that the eccentric engagement protrusions 124 of the cam body 120 are engaged with one side of the hook body 110, The hook body 110 rotates about the hinge axis 112 in the ascending or descending direction during each rotation of the cam body 120.

The locking groove 125 of the cam body 120 has a groove structure in which the oblique surface 126 and the engaging surface 127 are perpendicular to each other and the oblique surface 126 is a direction in which the cam body rotates in the forward direction And the engagement surface 127 is formed as a straight surface in the radial direction. Preferably, four engagement surfaces 127 are formed at an interval of 90 degrees along the circumferential direction of the cam body 120.

At this time, a stepped space 132 is formed in the lower part of the outer side surface of the cam body supporting block 130, and one or two of the cammed surfaces 121 of the cam body 120 The dog is exposed.

A cam body angle rotator 140 is provided to closely contact the cam machined surface 121 of the cam body 120 exposed through the stepped space 132 to rotate the cam body 120, The hooks 114 of the body 110 are fixedly mounted at all positions where the pallet 10 can be hooked.

For this purpose, the cam body angular rotating device 140 contacts the cam machined surface 121 of the cam body 120, and the hook 114 is pivoted to the pallet 10 in order to rotate the cam body 120 in the forward direction. A first spring 144 mounted in the fixed block 142 and a rear end fixed to the first spring 144 so as to be compressible, The front end portion is constituted by a first spring pin 146 which is brought into close contact with the cam working surface 121 of the cam body 120 to rotate the cam body 120 in the normal direction.

Since the hook body 110 including the cam body 120 and the housing 100 are mounted on the APC arm connected to the transfer device, the cam body 120 is moved to the hook body Of the cam body angular rotation device 140 fixedly mounted in a front position where the hook 114 can hook the pallet 10 when the first cam 110 rotates forward with the housing 100 and the pallet 10 together with the housing 100, As the spring pin 146 pushes the cam machined surface 121, the cam body 120 rotates in the forward direction.

In the cam body supporting block 130, a cam body angular rotation cut-off device 150 is arranged along the rotational direction of the cam body 120. The cam body angular rotation cut- The cam body 120 moves while pulling the pallet 10 together with the hook body 110 and the housing 100 and moving the cam body 120 while restricting the lock groove 125 of the cam body 120. [ To prevent each rotation in the reverse direction.

For this purpose, the cam body angular rotation cut-off device 150 includes a second spring 154 which is inserted in the rear of the cam body supporting block 130 so as to be compressible along the rotational direction of the cam body 120, 2 spring 154 and the front end of the second spring pin 156 is inserted into the lock groove 125 of the cam body 120 to prevent the cam body 120 from rotating in the reverse direction, .

The hook body 110 is tensioned when the hook body 110 is lifted and lowered between the bottom surface of the section between the hinge shaft 112 and the hook 114 of the hook body 110 and the bottom surface of the housing 100, A spring 116 for supporting the hook body is mounted.

Hereinafter, an operation flow of the pallet transporting hook device according to the present invention will be described.

FIG. 6 is a horizontal sectional view showing an operation flow of a hook device for transferring pallets of a machine tool according to the present invention, and FIG. 7 is a view showing an operation flow of a hook device for transferring pallets of a machine tool according to the present invention Fig.

The hook 114 of the hook body 110 must be hooked on one end bottom of the pallet 10 in order to transfer the pallet 10 to a desired position.

To this end, the APC arm moves forward toward the pallet as the mobile device is driven. At the same time, the APC arm is mounted on the housing 100, the hook body 110 in the housing 100, The cam body supporting block 130 mounted on one side portion and the cam body 120 rotatably disposed on the cam body supporting block 130 move forward toward the pallet 10 together.

At this time, since the cam body rotation device 140 is fixedly mounted on the front position where the hook 114 can hang the pallet 10, when the cam body 120 moves in the forward direction, The first spring pin 146 of the device 140 pushes the cam machined surface 121 of the cam body 120 and makes contact therewith.

That is, the first spring pin 146 pushes the cam machined surface 121 of the cam body 120 during the forward movement. As shown in the left side view of FIG. 6, the front end of the first spring pin 146 And the side end portion of the first spring pin 146 presses and pushes the vertical surface 122 so that the cam body 120 is in contact with the inclined surface 123 of the cam body 120, Deg.

At this time, the hook body 110 continues to advance, and the hook 114 is moved to the hooking position of the bottom end of one end of the pallet 10 as shown in the left side view of FIG. 7, 120 rotate 90 degrees, the hook body 110 rotates toward the ascending and descending direction, and the hook 114 is hooked on the bottom of one end of the pallet 10.

More specifically, since the eccentric engagement protrusions 124 formed on the inner surface of the cam body 120 are engaged with one side of the hook body 110, when the cam body 120 rotates by 90 degrees The hook 114 of the hook body 110 rotates about the hinge axis 112 in the vertical direction to be hooked on the bottom of one end of the pallet 10.

When the hook 114 is hooked on the bottom of the pallet 10, the APC arm moves backward according to the driving of the moving device. At the same time, the housing 100, on which the APC arm is mounted, A cam body supporting block 130 mounted on one side of the housing 100 and a cam body 120 rotatably disposed on the cam body supporting block 130 move back together And the pallet 10 hooked on the hook 114 are also moved back to the desired position.

The first spring pin 146 of the cam body angular rotating device 140 is moved back to the cam body 140 through the cam body 120. In this case, 120 in contact with the cam surface 121 of the cam.

However, even if the first spring pin 146 contacts the cam machined surface 121 again, the cam body 120 is not rotated in the opposite direction by the cam body angular rotation cut-off device 150.

More specifically, the second spring pin 156 of the cam block rotation preventing device 150 is inserted into the lock groove 125 of the cam body 120, that is, the lock groove The cam body 120 is prevented from rotating in the reverse direction because the cam body 120 is in a state of restricting the reverse rotation of the cam body 120 while being in close contact with the engaging surface 127 of the cam body 120. [

At this time, the first spring pin 146 of the cam body angular rotating device 140 is in line contact only along the inclined plane 123 of the cam working surface 121 when the cam body 120 is reversed.

As the cam body 120 is not angularly rotated in the reverse direction, the hook body 110 does not rotate any more, and the hook 114 keeps the pallet 10 being continuously hooked, Can be easily moved to a desired position by being guided by the hook 114. [

As described above, a simple structure including a cam body having a multistage cam machined surface and a multistage lock groove, a first spring pin for rotation guidance of the cam body and a second spring pin for restricting the angular rotation of the cam body, By using a mechanical mechanism, the hook body can be advanced and hooked to the pallet, and the pallet can be easily transported to a desired position while moving the hook body backward.

On the other hand, a wear-resistant coating layer is applied around the hinge shaft 112.

The abrasion resistant coating layer is formed by spraying a powder composed of 96 to 98% by weight of chromium oxide (Cr ₂ O ₃ ) and ₂ to 4% by weight of titanium dioxide (TiO ₂ ) onto the hinge shaft 112, And the hardness is plasma-coated to maintain 900 to 1000 HV.

The wear-resistant coating layer is formed by spraying powder composed of 96 to 98% by weight of chromium oxide (Cr ₂ O ₃ ) and ₂ to 4% by weight of titanium dioxide (TiO ₂ ).

The reason why the ceramic coating is applied to the outer peripheral surface of the hinge shaft 112 is to prevent abrasion and corrosion. Compared to chrome plating or nickel chrome plating, the ceramic coating is excellent in corrosion resistance, scratch resistance, abrasion resistance, impact resistance and durability.

Chromium oxide (Cr ₂ O ₃ ) acts as a passivity layer to block oxygen entering the inside of the metal, thereby preventing rusting.

Titanium dioxide (TiO ₂ ) is a white pigment because it is very stable physicochemically and has high hiding power. And is also widely used for ceramics having high refractive index because of high refractive index. And has characteristics of photocatalytic property and superhydrophilic property. Titanium dioxide (TiO ₂ ) acts as an air purification function, an antibacterial function, a harmful substance decomposition function, a pollution prevention function, and a discoloration prevention function. This titanium dioxide (TiO ₂ ) ensures that the wear-resistant coating layer is coated on the outer circumferential surface of the hinge shaft 112, and the foreign matter adhering to the wear-resistant coating layer is decomposed and removed to prevent the wear-resistant coating layer from being damaged.

Here, chromium oxide (Cr ₂ O ₃₎ and when using hayeoseo mixing titanium dioxide (TiO _2), the mixing ratio of these, chrome oxide (Cr ₂ O ₃₎ Titanium dioxide (TiO ₂₎ in 96-98% by weight 2 By weight to 4% by weight.

When the mixing ratio of chromium oxide (Cr ₂ O ₃ ) is less than 96 to 98%, the covering of chromium oxide (Cr ₂ O ₃ ) is often broken in an environment of high temperature and the like, ) Of the outer circumferential surface of the outer circumferential surface of the outer circumferential surface of the inner circumferential surface of the outer circumferential surface of the outer circumferential surface

When the mixing ratio of titanium dioxide (TiO ₂ ) is less than 2 to 4 wt%, the effect of titanium dioxide (TiO ₂ ) is insignificant so that the purpose of mixing it with chromium oxide (Cr ₂ O ₃ ) is discolored. That is, titanium dioxide (TiO ₂ ) dissolves and removes foreign matter adhering to the outer peripheral surface of the hinge shaft 112 to prevent the outer peripheral surface of the hinge shaft 112 from being corroded or damaged. The mixing ratio thereof is 2 to 4 weight %, There is a problem that it takes much time to decompose the attached foreign matter.

The coating layer made of these materials is plasma-coated to have a thickness of 50 to 600 mu m around the outer peripheral surface of the hinge shaft 112, a hardness of 900 to 1000 HV, and a surface roughness of 0.1 to 0.3 mu m.

The abrasion resistant coating layer is sprayed with the powder powder and the gas at 1400 DEG C at a Mach 2 speed around the outer circumferential surface of the hinge shaft 112 and is sprayed at 50 to 600 mu m.

If the thickness of the wear-resistant coating layer is less than 50 탆, the above-mentioned effect of the ceramic coating layer can not be guaranteed. If the thickness of the wear-resistant coating layer exceeds 600 탆, the above- There is a problem that working time and material cost are wasted.

The outer circumferential surface of the hinge shaft 112 is raised while the wear prevention coating layer is coated on the outer circumferential surface of the hinge shaft 112. The outer circumferential surface of the hinge shaft 112 Cooled by a cooling device (not shown) to maintain a temperature of 150 to 200 ° C.

A sealing material made of anhydrous chromic acid (CrO ₃ ) made of a metal-based glass quartz system may further be applied to the periphery of the abrasion-resistant coating layer. Anhydrous chromic acid is applied as an inorganic sealing material around a coating layer made of chromium nickel powder.

Anhydrous chromic acid (CrO ₃ ) is used in places that require high abrasion resistance, lubricity, heat resistance, corrosion resistance and releasability, is not discolored in the atmosphere, has high durability, and has good abrasion resistance and corrosion resistance. The coating thickness of the sealing material is preferably about 0.3 to 0.5 mu m. If the coating thickness of the sealing material is less than 0.3 占 퐉, the sealing material easily peels off even in a slight scratch groove, so that the above-mentioned effect can not be obtained. If the coating thickness of the sealing material is made thick enough to exceed 0.5 탆, pin holes, cracks, and the like will increase on the plated surface. Therefore, the coating thickness of the sealing material is preferably about 0.3 to 0.5 mu m.

Therefore, since the coating layer having excellent abrasion resistance and oxidation resistance is formed around the outer circumferential surface of the hinge shaft 112, the outer circumferential surface of the hinge shaft 112 is prevented from being worn or oxidized, thereby extending the service life of the product.

Further, the hook 114 is made of nodular cast iron. The nodular cast iron is heated to a temperature of 1600 to 1650 ° C to be molten, then subjected to desulfurization treatment, and subjected to spheroidizing treatment at a temperature of 1500 to 1,550 ° C by adding a spheroidizing agent containing magnesium in an amount of about 0.3 to 0.7% by weight, followed by heat treatment.

Since nodular cast iron is a cast iron in which graphite is spherically crystallized during the solidification process by adding magnesium or the like to the molten metal of the common gray cast iron, the shape of the graphite is spherical compared to gray cast iron. Since the nodular cast iron has a small notch effect, the stress concentration phenomenon is reduced and the strength and toughness are greatly improved.

The hook 114 of the present invention is made by melting a nodular cast iron at 1600 to 1650 ° C to obtain a molten metal, subjecting it to desulfurization, adding a spheroidizing agent containing about 0.3 to 0.7% by weight of magnesium, Followed by heat treatment.

Here, when the nodular cast iron is heated to less than 1600 ° C, the entire structure is not sufficiently melted. If the cast iron is heated above 1650 ° C, unnecessary energy is wasted. Therefore, it is preferable to heat the nodular cast iron to 1600 to 1650 ° C.

When the amount of magnesium is less than 0.3% by weight, the effect of injecting the spheroidizing agent is negligible. When the amount of magnesium is less than 0.3% by weight, the effect of injecting spheroidizing agent is insignificant. When the amount of magnesium is less than 0.3% There is a problem in that an expensive material cost is increased. Therefore, the mixing ratio of magnesium in the spheroidizing agent is preferably about 0.3 to 0.7% by weight.

When the spheroidizing treatment agent is injected into the molten nodular cast iron, it is subjected to spheroidizing treatment at 1500-1550 ° C. If the spheroidizing treatment temperature is lower than 1500 ° C., the spheroidizing treatment is not properly performed. If the spheroidizing treatment temperature is higher than 1550 ° C., the spheroidizing treatment effect is not greatly improved, but unnecessary energy is wasted. Therefore, the spheroidization treatment temperature is preferably 1500 to 1550 ° C.

Since the hook 114 of the present invention is made of the nodular cast iron, the stress concentration phenomenon is reduced because the notch effect is small, and the strength and toughness are greatly improved.

The outer surface of the housing 100 may be coated with a polypropylene resin composition having excellent impact resistance against external impact or external environment. The polypropylene resin composition comprises a polypropylene random block copolymer composed of 75 to 95% by weight of an ethylene-propylene-alphaolefin random copolymer and 5 to 25% by weight of an ethylene-propylene block copolymer having an ethylene content of 20 to 50% by weight .

The polypropylene random block copolymer is preferably 75 to 95% by weight of the ethylene-propylene-alphaolefin random copolymer and 5 to 25% by weight of the ethylene-propylene block copolymer. The ethylene- When the content of the ethylene-propylene block copolymer is less than 5% by weight, the impact resistance is deteriorated. When the content of the ethylene-propylene block copolymer is more than 25% by weight, the rigidity is deteriorated do.

Wherein the ethylene-propylene-alpha olefin random copolymer comprises 0.5 to 7% by weight of ethylene and 1 to 15% by weight of an alpha-olefin having 4 to 5 carbon atoms and improves mechanical stiffness and heat resistance of the polypropylene resin composition, As shown in Fig. The ethylene content is preferably from 0.5 to 5% by weight, more preferably from 1 to 3% by weight. When the content of ethylene is less than 0.5% by weight, the whitening resistance is deteriorated. When the content is more than 7% by weight, . Further, the alpha olefin means any alpha olefin except ethylene and propylene, and is preferably butene. When the number of carbon atoms is less than 4 or more than 5, the reactivity of the alpha-olefin with the comonomer is low during the production of the random copolymer, making it difficult to produce the copolymer. Further, it may contain 1 to 15% by weight, preferably 1 to 10% by weight, and more preferably 3 to 9% by weight of the above-mentioned alpha olefin. If the amount of the alpha-olefin is less than 1% by weight, the crystallinity becomes higher than necessary and the transparency is lowered. When the amount of the alpha-olefin is more than 15% by weight, the crystallinity and rigidity are lowered and the heat resistance is significantly lowered.

In addition, the ethylene-propylene block copolymer contains 20 to 50% by weight of ethylene and imparts impact resistance to the polypropylene resin composition and enables finely dispersing, thereby imparting both whitening resistance and transparency. The ethylene content may preferably be 20 to 40% by weight, and if it is less than 20% by weight, the impact resistance is deteriorated. If it exceeds 50% by weight, the impact resistance and whitening resistance may be deteriorated.

Therefore, since the polypropylene resin composition is coated on the outer surface of the housing 100, the impact resistance and whitening resistance are improved, thereby extending the service life of the product.

10: pallet 11: first pallet
12: second pallet 13: third pallet
14: APC arm 16: housing
17: spring support pin 18: hinge shaft
20: hook body 22: hook
24: diagonal plane 26: spring support groove
28: spring 30: air cylinder
100: housing 110: hook body
112: Hinge shaft 114: Hook
116: hook body supporting spring 120: cam body
121: cam working surface 122: vertical surface
123: slope 124: eccentric engaging projection
125: locking groove 126: diagonal plane
127: engaging surface 130: cam body supporting block
132: stepped space 140: cam body Each rotating device
142: fixed block 144: first spring
146: first spring pin 150: cam body angular rotation cut-off device
154: second spring 156: second spring pin

Claims (4)

A hook body 110 rotatably mounted in the housing 100 fixed on the APC arm by a hinge shaft 112 at a rear end thereof and having a hook 114 formed at a front end thereof;
A plurality of cam working surfaces 121 are formed on the outer surface of the hook body 110 so that the vertical surface 122 and the inclined surface 123 are perpendicular to each other for rotation of the hook body 110. On the inner surface of the hook body 110, And an eccentric engagement protrusion 124 is formed integrally with the outer circumferential surface of the hook body 125. A plurality of locking grooves 125 A cam body 120 formed at regular intervals;
A cam body supporting block 130 fixedly mounted at one side of the housing 100 and having a structure in which the rotation axis of the cam body 120 is rotatably mounted while the cam body 120 is wrapped and protected;
The hook 114 is fixed to a front position where the pallet 10 can be hooked so that the cam body 120 rotates in a forward direction while being in contact with the cam working surface 121 of the cam body 120, Each rotating device 140;
The cam body 120 is inserted in the cam body support block 130 along the rotation direction of the cam body 120 to restrict the rotation of the cam body 120 in the reverse direction while restricting the lock groove 125 of the cam body 120 Cam body angular rotation cut-off device (150);
And a hook for moving the pallet.
The method according to claim 1,
A stepped space 132 is formed on the outer side of the cam body supporting block 130 and the cammed surface 121 of the cam body 120 is exposed to the outside through the stepped space 132;
Wherein a hook (116) for supporting a hook body is further mounted between a bottom surface of the hook body (110) and a bottom surface of the housing (100).
The method according to claim 1,
The cam body angle rotator 140 includes:
A fixing block 142 fixedly mounted at a front position where the hook 114 can hang the pallet 10;
A first spring 144 mounted within the fixed block 142;
And a front end portion of the first spring pin 146 is pressed against the cam working surface 121 of the cam body 120 so as to rotate the cam body 120 in the forward direction, );
And a hook mechanism for transferring the pallet of the machine tool.
The method according to claim 1,
The cam body angular rotation cut-off device 150 includes:
A second spring 154 compression-fitted in the rear of the cam body support block 130 along the rotational direction of the cam body 120;
And the front end of the second spring 154 is inserted into the lock groove 125 of the cam body 120 to prevent the cam body 120 from rotating in the reverse direction, (156);
And a hook mechanism for transferring the pallet of the machine tool.

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