JPH11239937A - Pallet clamping device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly mount even a heavy pallet on a table, and to fix the pallet on the table by suppressing distortion to the minimum. SOLUTION: A clamping means 11 is provided with a reference surface 12 to be mounted with a pallet 41 conveyed from the outside along a linear conveying path and a clamping part 14 clamping a clamped part 43 provided in a lower surface of the pallet 41 to bring it into close contact with the reference surface 12. The pallet clamping device is provided with a lift plate 21 engaging the clamping means 11 with a pallet fixing means 10 arranged at least in three points on a machine tool table 1 and with the pallet conveyed to guide the pallet upward of the table 1 and to vertically move it, and a pallet lifting means 20 to mount the pallet on the reference surface 12 by lowering down the lift plate 21, and to guide the clamped part 43 to the clamping part 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pallet clamping device for fixing a pallet conveyed from outside on a table of a machine tool.

[0002]

2. Description of the Related Art In a machine tool such as a machining center, in order to shorten a setup time for attaching and detaching a work, etc.
Conventionally, an APC device (automatic pallet changing device) has been used. Generally, this APC device includes a pallet clamp device for fixing a pallet on a table of a machine tool,
A pallet transport device that transports the pallet onto the table and discharges the pallet from the table. Conventionally, as a clamp device for fixing a pallet on this table, those disclosed in Japanese Utility Model Laid-Open No. 3-29246 and Japanese Patent Application Laid-Open No. 57-127636 are known.

The former, that is, the clamp device disclosed in Japanese Utility Model Laid-Open Publication No. 3-29246, includes clamp portions 60 arranged at four places on a table 54 as shown in FIG. As shown in FIG. 5, each of the clamp portions 60 includes a tapered reference surface 63 provided to project from the upper surface of the table 54, a collet 62 provided at the center of the reference surface 63, A hydraulic cylinder 61 for driving the collet 62 is provided. In addition, pallet 5
3, on the lower surface of the base 3 at a position corresponding to the clamp 60,
A shaft-shaped gripped portion 55 and an inner tapered receiving surface 56 are provided.

According to this clamping device, the pallet 53
Is transported onto the table 54, and the gripped portion 55 of the pallet 53 is inserted into the collet 62, and the receiving surface 56 of the pallet 53 is brought into contact with the reference surface 63.
The hydraulic cylinder 61 is driven to operate the collet 62, and the collet 62
The receiving surface 56 of the pallet 53 comes into close contact with the reference surface 63, and the pallet 53 is fixed on the table 54.

As described above, according to this clamp device,
Each clamp unit 60 disposed on the table 54
The pallets 53 are individually supported and clamped, so that when the pallets 53 are fixed on the table 54, there is no problem that the pallets 53 are distorted by the clamps. This has the effect of maintaining good accuracy.

Incidentally, a pallet transfer device as shown in FIG. 4 has been conventionally applied to this clamp device. This pallet transport device has a pallet holding portion 51a at each end, and a turning arm 51 rotatably supported in a direction indicated by an arrow by a support portion 52, and a drive motor for rotating the turning arm 51 in the direction indicated by an arrow. (Not shown), and elevating means (not shown) for moving the turning arm 51 up and down along the rotation center axis.
Is rotated to convey the pallet 53 held by the pallet holding portion 51a above the table 54, and then the pallet 53 can be placed on the table 54 by moving the turning arm 51 downward. After the pivot arm 51 is moved upward, the pallet 53 can be discharged from the table 54 by rotating the pivot arm 51.

On the other hand, the latter, that is, Japanese Patent Application Laid-Open No. 57-1276
As shown in FIG. 6, the clamp device disclosed in Japanese Patent Publication No. 36-136 has a support member 76 provided on a table 75, an elevating plate 73 movably provided in a vertical direction, and a vertically moving plate 73. Hydraulic cylinder 7 to be moved
4, the supporting member 76 is provided with a fitting projection 76a on the upper surface, and the lifting plate 73 is provided with an engaging portion 73a having a T-shaped cross section on the upper surface of a flat plate. Have been. On the other hand, the pallet 71
Fitting hole 7 for fitting with fitting projection 76a of support member 76
It has a supported member 77 having 7a and a T-shaped engaging groove 71a that engages with the engaging portion 73a of the elevating plate 73. Guide rails 72 are provided on both sides of the upper surface of the elevating plate 73, and rolling rollers 78 which engage with the guide rails 72 are provided on the lower surface of the pallet 71.

According to this clamping device, the engaging portion 73a of the elevating plate 73 and the engaging groove 7 of the pallet 71
By driving the hydraulic cylinder 74 to lower the elevating plate 73 in a state where the supporting member 1a is engaged with the fitting protrusion 76a provided on the supporting member 76 and the supported member 7a.
7, the lower end surface of the supported member 77 and the upper end surface of the support member 76 come into contact with each other, and the pallet 71 is positioned on the table 75; It is fixed. Conversely, the hydraulic cylinder 74 is driven to
Is raised, the guide rail 72 and the rolling roller 78 engage with each other, and the pallet 71 is lifted upward, whereby the fitting protrusion 76a and the fitting hole 77 are formed.
The pallet 71 is released from the table 75 to the outside.

In FIG. 6, reference numeral 79 denotes a link arm.
The lift arm 73 rotates in accordance with the vertical movement of the lift plate 73, and swings the swing arm 81 engaged with the lift plate 73 in the direction of arrow EF. An engaging claw 82 is provided at the tip of the swing arm 81, and the swing arm 81 is
When swinging in the direction, the engaging claw 82 is engaged with an engaging member 83 provided on a side surface of the pallet 71. Reference numeral 80 denotes a transfer shaft, which is movable in the axial direction, that is, in a direction orthogonal to the paper surface, and swings in the direction of arrow E to engage the engaging claw 82 with the engaging member 83. The oscillating arm 81 engaged with the pallet 71 is moved in the axial direction, so that the pallet 71 can be carried in above the table 75 and discharged from above the table 75 to the outside. The pallet 71 is guided by the guide rail 72 by the engagement between the guide rail 72 and the rolling roller 78, and is movable along the guide rail 72.

[0010]

However, the conventional pallet clamping devices described above have the following problems.

That is, in the clamp device disclosed in Japanese Utility Model Laid-Open No. 3-29246, as described above, the pallet 5 is individually set by each of the plurality of clamp portions 60.
3 is supported and clamped, so that the pallet 53 can be fixed on the table 54 with high accuracy. On the other hand, a means for guiding the pallet 53 on the table 54 is provided. Therefore, the loading and unloading of the pallet 53 must be carried out by a transport means such as the above-mentioned swivel arm 51 which overhangs and holds the pallet 53. Since the operation and the elevating operation cannot be performed quickly, there has been a problem that the conveying speed of the pallet 53 is reduced. In addition, it is necessary to make the swing arm 51 high in rigidity or to use a drive motor (not shown) having a large output. There was also the problem of becoming.

On the other hand, in the clamping device disclosed in Japanese Patent Application Laid-Open No. 57-127636, the pallet 71 is supported by the guide rail 72 and the rolling roller 78 engaged with the guide rail 72, and the pallet 71 is held on the table 75. Since the pallet 71 is guided upward, even if the weight of the pallet 71 is considerably heavy, the problem that the transport speed of the pallet 71 becomes extremely slow does not occur, and the entire apparatus becomes large. Although there is no problem that the equipment cost is increased, the working position of the acting force of the lifting plate 73 for pulling down the pallet 71 and the pallet 71
There is a problem that the pallet 71 is easily distorted by the bending moment because the supporting position of the supporting member 76 for supporting the pallet 71 is far away. Further, since the engaging portion 73a of the elevating plate 73 comes into contact with a wide area of the bottom surface of the engaging groove 71a and pulls it downward, when the operation is repeated, the bottom surface and the engaging portion There is also a problem that the state of contact with the pallet 73a is not constant, and the state of deformation of the upper surface of the pallet 71 becomes non-uniform, so that the work cannot be processed with high accuracy.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and even a heavy pallet can be quickly mounted on a table. An object of the present invention is to provide a pallet clamping device that can be fixed.

[0014]

Means for Solving the Problems and Their Effects According to the first aspect of the present invention, there is provided a pallet transported from the outside along a linear transport path on a table of a machine tool. A reference surface on which the pallet is placed, and a gripper for gripping a gripped portion provided on the lower surface of the pallet and bringing the pallet into close contact with the reference surface. Clamp means is engaged with the pallet fixing means provided at three or more places on the table, and the pallet conveyed along the linear conveyance path, and the pallet is placed above the table. An elevating plate for guiding and elevating the pallet by moving up and down, and by lowering the elevating plate, placing the pallet on a reference surface of the fixing means; It is characterized in that which is configured by providing a pallet lifting means for guiding the gripped portion of the pallet to said gripping portion.

According to the present invention, first, the pallet transported from the outside along the linear transport path is engaged with the lifting plate, and is guided above the table by the lifting plate. Next, the pallet is placed on the reference surface of the fixing means by driving the elevating means to lower the elevating plate, and the gripped part of the pallet is guided to the gripping part of each clamp means. Thereafter, by gripping the gripped portion of the pallet with the gripping portion of the clamping means, the pallet is positioned in close contact with the reference surface,
Fixed on the table. Conversely, by releasing the gripping of the gripped portion by the gripping portion of the clamp means, and then driving the elevating means to raise the elevating plate, the pallet can be discharged to the external transport path. .

As described above, according to the present invention, the pallet is engaged with the elevating plate to guide the pallet above the table, and after the pallet is supported by the elevating plate, the elevating plate is lowered. The pallet is placed on the reference surface, so that even when the weight of the pallet is considerably heavy, the pallet can be quickly moved to the pallet as compared with the conventional pallet transfer using the above-described swivel arm. It can be transported and placed on the reference surface. Further, there is no problem that the weight of the pallet is increased, the conventional apparatus as a whole becomes large, or the equipment cost is increased.

In addition, since the clamping means are provided at three or more places on the table, and the pallets are individually supported and clamped by the respective clamping means, the pallets are clamped when the pallet is fixed on the table. As a result, it is possible to maintain the processing accuracy of the work well.

According to a second aspect of the present invention, in the first aspect of the present invention, the tilting plate is prevented from tilting forward from the horizontal state toward the pallet loading side downward from the horizontal state. Means.

When the pallet conveyed from the outside engages with the lifting plate at the rising end position, the weight of the pallet acts on the pallet loading side end of the lifting plate in an uneven manner, whereby the lifting plate moves. Although it receives a moment directed downward on the pallet loading side, according to the present invention, since the tilting prevention means is provided to prevent the lifting plate from leaning forward from the horizontal state toward the pallet loading side downward, Even when the moment acts, the lifting plate can be maintained in a horizontal state, and the pallet can be smoothly loaded onto the lifting plate. This is the same when the pallet is discharged from the lifting plate.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the release confirming means for detecting whether or not the release operation of the gripping portion is completed, and the lifting and lowering means It is provided with an ascending confirmation means for detecting whether or not the ascending operation is completed.

According to this invention, after releasing the gripped portion by releasing the gripped portion by the gripping portion of the clamp means and then lifting the pallet by lifting the lifting plate, Whether or not the release operation of the unit has been completed is detected by the release confirmation means. Thereby, the pallet can be lifted after the release operation of the grip portion is completed, and the inconvenience due to the pallet rising in a state where the release operation of the grip portion is not completed, that is, the grip portion and the gripped portion are The inconvenience that the part is damaged due to interference can be effectively prevented.

Further, when the lifting plate is raised and the pallet engaged with the lifting plate is discharged to the outside, it is determined whether or not the lifting operation of the lifting means is completed, ie, whether or not the lifting of the lifting plate is completed. Can be detected by the ascending confirmation means, which is disadvantageous in that the pallet is discharged in a state where the pallet has not been lifted, that is, the grasped portion of the pallet and the grasping portion of the clamp means interfere with each other. The inconvenience that the part is damaged can be effectively prevented.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a sectional view showing a table on which a pallet clamp device according to the present embodiment is mounted, and FIG. 2 is a plan view thereof. FIG. 1 shows a cross section taken along the line DD in FIG.

As shown in FIGS. 1 and 2, the pallet clamping device according to the present embodiment comprises a pallet fixing means 10, a release confirming means 18, a pallet elevating means 20, a tilt preventing means 24 and a lifting means 24 provided on a pallet base 1. Checking means 28
The details of each unit will be described below. The pallet base 1 is supported by the table main body 2 so as to rotate horizontally by a driving unit (not shown).

As shown in FIG. 2, the pallet fixing means 10 comprises clamp means 11 arranged at equal intervals at four places on the pallet base 1, and as shown in FIG. A reference surface 12, which is provided so as to protrude from the upper surface of the pallet base 1 and has a tapered shape having a smaller diameter as it goes upward, a clamp chamber 13 provided at the center thereof, And a hydraulic drive unit 15 for driving the collet 14. The hydraulic drive unit 15 includes a cylinder chamber 15c provided below the clamp chamber 13.
Is inserted into the cylinder chamber 15c and its tip 1
5b is a piston 15a engaged with the collet 14,
A first hydraulic oil supply unit (not shown) for supplying hydraulic oil into the cylinder chamber 15c is provided. When the piston 15a moves downward, the tip of the collet 14 closes while the piston 15a moves upward. By doing so, the tip of the collet 14 is opened.

As shown in the figure, the lower surface of the pallet 41 is provided with a shaft-like gripped portion 43 and an inner tapered receiving surface 42 at respective positions corresponding to the respective clamping means 11. The gripped portion 43 is inserted into the collet 14 and is placed on the pallet base 1 in a state where the reference surface 12 and the receiving surface 42 are in contact with each other.

The release confirming means 18 comprises a pressure oil supply passage 16 opened at the upper end of the cylinder chamber 15c,
A first pressure sensor (not shown) for detecting the oil pressure in the pressure oil supply passage 16 and a first pressure oil supply unit (not shown) for supplying pressure oil to the pressure oil supply passage 16 When the piston 15a reaches the rising end, the opening of the pressure oil supply passage 16 is closed by the piston 15a, whereby the oil pressure in the pressure oil supply passage 16 rises, and The completion of the rise of the piston 15a can be detected by the detection by the first pressure sensor.

As shown in FIGS. 1 and 2, the pallet elevating means 20 engages with and supports a pallet 41 conveyed from the outside, and moves the elevating plate 21 up and down. Hydraulic drive unit 22
And a center shaft 2 provided at the center of the pallet base 1
2d.

The elevating plate 21 is made of a plate-like member, and has guide rollers 23 on both sides 21a. The pallet 41 is provided with a T-shaped engaging groove 41a as viewed from the side in the direction of arrow A in FIG. 1, and the pallet 41 is transported linearly in the direction of arrow B as shown in FIG. Then, the elevating plate 21 is relatively inserted into the engagement groove 41a, and the pallet 41 is guided by the guide roller 23, is carried in above the pallet base 1, and is supported by the guide roller 23. It has become.

The hydraulic drive unit 22 is fitted into a cylinder 22a provided at the center of the pallet base 1 and into a cylinder chamber 22b of the cylinder 22a. A piston 22c;
A second hydraulic oil supply unit (not shown) for supplying hydraulic oil into the cylinder chamber 22b;
By moving c vertically, the lifting plate 21 moves up and down. The piston 22c is fitted around the center shaft 22d, and moves up and down in the axial direction of the center shaft 22d.

The tilt preventing means 24 includes an anti-tilt shaft 25 provided at the end of the elevating plate 21 in the direction of arrow B so as to hang downward.
And a cover 27 which is provided on the pallet base 1 at a position corresponding to the lower end and into which the lower end of the tilt prevention shaft 25 is loosely inserted, and which is fitted on the tilt prevention shaft 25 and closes the opening of the recess 27. The tilt-preventing shaft 25 moves up and down together with the elevating plate 21. When the elevating plate 21 reaches the rising end, the flange portion 25a provided at the lower end of the tilt-preventing shaft 25 has a lid. The lower surface 26 is brought into contact with and locked.

The rising confirmation means 28 includes a pressure oil supply passage 28a opened at the upper end of the cylinder chamber 22b, a second pressure sensor (not shown) for detecting the oil pressure in the pressure oil supply passage 28a, And a second pressure oil supply unit (not shown) for supplying pressure oil to the pressure oil supply passage 28a. When the piston 22c reaches a rising end, the pressure oil supply is performed by the piston 22c. The opening of the passage 28a is closed, whereby the pressure oil supply passage 28a is closed.
The rise of the hydraulic pressure in the piston 22c is detected by the second pressure sensor, so that the completion of the rise of the piston 22c can be detected.

Next, the operation of the pallet clamping device according to the present embodiment having the above configuration will be described. still,
As shown in FIG. 1, the lifting plate 21 is
And the piston 15a is located at the rising end, and the tip of the collet 14 is open.

As shown in FIG. 2, when the pallet 41 is guided by the guide rails 44 and is linearly carried in from the outside in the direction indicated by the arrow B, the lifting plate 21 moves relative to the engaging grooves 41a of the pallet 41. The pallet 41 is inserted, guided by the guide rollers 23, carried in above the pallet base 1, and supported by the guide rollers 23.

When the lifting / lowering plate 21 is inserted into the engaging groove 41a of the pallet 41, the weight of the pallet 41 acts on the end of the lifting / lowering plate 21 in the direction indicated by the arrow C, and the lifting pallet 21 is moved in the direction indicated by the arrow C. Although receiving a moment of tilting downward, as described above, the flange portion 25a of the tilt prevention shaft 25 is in contact with and locked to the lower surface of the lid body 26, whereby the lifting pallet 21 moves downward in the arrow C direction. Is prevented from tilting. Therefore, the lift plate 21 is maintained in a horizontal state, and there is no step or displacement between the guide rail 44 and the lift plate 21. Thereby, the pallet 41 can be smoothly carried onto the lifting plate 21. This is the same when the pallet 41 is discharged. The problem that the lifting plate 21 rotates about the axis is also prevented by the tilt prevention shaft 25.

Next, when the hydraulic drive unit 22 is driven to lower the elevating plate 21, each gripped part 43 provided on the lower surface of the pallet 41 is moved to the collet 14 of each clamp means 11.
The pallet 41 is placed on the pallet base 1 when the reference surface 12 of the clamping means 11 and the receiving surface 42 of the pallet 41 come into contact with each other.

Thereafter, when the hydraulic drive unit 15 of each clamping means 11 is driven to move the piston 15a downward, the tip of the collet 14 closes and the gripped portion 43 of the pallet 41 is gripped by the collet 14. You.

As described above, the pallet 41 can be carried in from the outside, placed on the pallet base 1, and fixed. This state is shown in FIG.

As described above, according to the pallet clamping device, the pallet 41 is engaged with the lifting plate 21 to guide the pallet 41 above the pallet base 1, and the pallet 4 is moved by the lifting plate 21.
Since the pallet 41 is placed on the reference surface 12 by lowering the elevating plate 21 after supporting the pallet 41, even if the weight of the pallet 41 is considerably heavy, the above-described conventional swivel arm can be used. The pallet 41 can be quickly conveyed and placed on the reference surface 12 as compared with the case where the pallet is used. Further, the entire device as in the related art, which is caused by the increase in the weight of the pallet 41, becomes large.
Alternatively, there is no problem that the equipment cost increases.

The pallets 41 are fixed on the pallet base 1 because the clamping means 11 are provided at four places on the pallet base 1 and the pallets 41 are individually supported and clamped by the respective clamping means 11. In doing so, there is no problem that the pallet 41 is distorted by the clamp, and as a result, the processing accuracy of the work can be favorably maintained.

Next, the hydraulic drive unit 15 is driven to move the piston 15a upward to open the tip of the collet 14 and release the gripping of the gripped portion 43. On the other hand, when the piston 15a reaches the rising end, the opening of the pressure oil supply path 16 is closed by the piston 15a, whereby the oil pressure in the pressure oil supply path 16 increases, and the piston 15a is detected by the first pressure sensor. Has reached the rising end, that is, it is detected that the grip by the collet 14 has been released.

After it is detected that the grip by the collet 14 has been released in this way, the hydraulic drive unit 22 is driven to raise the piston 22c, and the lift plate 2
1 and the pallet 41 which engages the same are moved upward. As a result, the sheet can be discharged onto the external guide rail 44. On the other hand, when the piston 22c reaches the rising end, the opening of the pressure oil supply passage 28a is closed by the piston 22c, whereby the oil pressure in the pressure oil supply passage 28a increases, and the piston 22c is detected by the second pressure sensor.
Has reached the rising end, that is, it is detected that the pallet 41 has reached the rising end and the gripped portion 43 has completely come out of the clamping means 11. Then, after it is detected that the pallet 41 has reached the rising end and the gripped portion 43 has completely come out of the clamping means 11, the pallet 41 is carried out.

Thus, according to this clamping device,
After the release confirming means 18 confirms that the gripping of the grasped portion 43 by the collet 14 has been released, the pallet 41
Is moved upward, so that the collet 14
Pallet 41 can be prevented from rising in a state where the release (release) operation of the pallet is not completed, and the inconvenience that the collet 14 and the gripped portion 43 interfere with each other and damage the same is effectively prevented. Can be.

After the pallet 41 is taken out of the pallet 41 after the pallet 41 is taken out of the pallet 41 after confirming that the grasped portion 43 has completely come out of the clamp means 11 by the ascending confirmation means 28, The inconvenience that the clamp means 11 interferes with the collet 14 to damage the same can be effectively prevented.

Although the embodiments of the present invention have been described in detail, it goes without saying that the specific aspects of the present invention are not limited to these embodiments. For example, in the above example,
By detecting the rising end of the piston 22c of the pallet lifting / lowering means 20, the completion of lifting of the pallet 41 is detected. However, the present invention is not limited to this. For example, the lifting of the tilt preventing shaft 25 of the tilt preventing means 24 may be performed. The completion of the lifting of the pallet 41 may be detected by detecting the end. The clamp means 11 need not be provided at four places as in the present embodiment, but may be provided at at least three places at appropriate intervals.
There is no particular concern if 1 can be fixed stably and accurately.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a table on which a pallet clamping device according to an embodiment of the present invention is mounted.

FIG. 2 is a plan view of the table shown in FIG. 1;

FIG. 3 is a cross-sectional view showing a state where the pallet is fixed by the pallet clamping device according to the embodiment.

FIG. 4 is a perspective view showing a conventional pallet clamping device and a pallet transport device.

FIG. 5 is a cross-sectional view showing the pallet clamping device shown in FIG.

FIG. 6 is a sectional view showing another conventional pallet clamping device and pallet transport device.

[Explanation of symbols]

 Reference Signs List 1 Pallet base 2 Table body 10 Pallet fixing means 11 Clamping means 12 Reference surface 14 Collet 15 Hydraulic drive unit 18 Release confirmation means 20 Pallet elevating means 21 Elevating plate 22 Hydraulic drive unit 24 Tilt prevention means 28 Elevation confirmation means 41 Pallet 42 Receiving surface 43 gripped part

Claims (3)

[Claims] 1. A clamping device for fixing a pallet conveyed from the outside along a linear conveyance path on a table of a machine tool, comprising: a reference surface on which the pallet is placed; and a lower surface of the pallet. A pallet fixing means provided with gripping means provided at three or more positions on the table, the gripping means having a gripping portion for gripping the gripped portion provided and bringing the pallet into close contact with the reference surface; A lifting plate that engages with the pallet conveyed along the conveyance path, guides the pallet above the table, and vertically moves the pallet up and down. The pallet is placed on the reference surface of the fixing means, and pallet elevating means for guiding the gripped portion of the pallet to the gripping portion is provided. Pallet clamping device comprising and. 2. The pallet clamping device according to claim 1, further comprising a tilt preventing means for preventing the lifting plate at the raising end position from tilting forward from the horizontal state toward the pallet loading side. 3. The apparatus according to claim 1, further comprising: release confirmation means for detecting whether or not the release operation of the grip portion has been completed, and ascending confirmation means for detecting whether or not the lifting operation of the elevating means has been completed. 2. The pallet clamp device according to 2.