JPH0355368B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a tact system-type work pallet circulation conveyance equipment for assembly line work, in which the conveyance device is stopped during work and starts when the assigned work is completed, thereby reducing takt time. To provide a device that can increase productivity and prevent workpiece position shift due to stop impact.

<Prior art> As shown in FIG. 5, the basic structure of the tact system type conveyance equipment that is the object of the present invention is that a large number of work pallets P are transferred from a tact conveyance device 1 for assembly to a transfer device 2 for unloading, and a conveyance device for return. The structure is configured such that the tact conveyance device 1 for assembly is circularly conveyed in order through the device 3 and the transfer device 4 for loading, and the tact conveyance device 1 for assembly is configured to intermittently drive the conveyance belt 6 with an intermittent drive device 5. , a work pallet P is sequentially and intermittently conveyed between stations S and then stopped.

In general tact system type conveyance equipment, the work pallet P is simply placed on the conveyance band 6 made of synthetic resin belt such as rubber, cloth, nylon, etc. and is conveyed in a tact manner by friction transmission. Because the belt extends by absorbing
(in the direction away from the drive side).

Therefore, when the conveyance device 1 is driven by the intermittent drive device 5, the work pallet P is transported almost tact-wise from one station S to the next station S on the drive side, but the work pallet P is transported at a distance away from the drive side. The tact feed is performed only to the front side of each station S, and the center position of the predetermined station S cannot be reached.

Therefore, in order to align the center of the work pallet P with the center of the station S, conventionally, the conveyor belt 6
The work pallet P is sent in a tact larger than the gap between the conveyors S to prevent the work pallet P from remaining in front of each station S, and the work pallet P that is about to be sent beyond the station S is transported between the two belts. The pallet is configured to be stopped by pallet stopping means attached to the intermediate portion.

<Problems to be Solved by the Invention> In the prior art described above, the following problem occurs because the conveyance belt 6 is fed in a tact larger than the station gap.

(1) Since the tact feeding time includes the time required for excess tact feeding, it is longer than when tact feeding the station gap appropriately, which increases the time required for assembly line work itself and reduces productivity. do.

(2) As shown in Figure 6, surplus tact feed curve B
Then, the speed of the workpiece pallet P when it reaches the predetermined station S after tact feeding is V, and the speed becomes zero as in the case of proper tact feeding through the station gap (refer to the appropriate tact feeding curve A). Therefore, when the work pallet P is received by the pallet stopping means, the stop impact causes the work to shift relative to the work pallet.

(3) Pallet stopping means must be added to the conveyance belt, which complicates the structure of the tact conveyance device.

(4) Furthermore, in the conventional technology, the work pallet P is simply placed on the belt-shaped conveyance band 6 and frictional transmission is performed. Therefore, when the conveyance speed becomes large, this frictional force will cause the work pallet P to be transferred to the conveyance band 6. The pallet cannot be positioned on top of the conveyor belt, and the pallet slides backward on the conveyor belt.

Furthermore, if the weight to be conveyed is large, the inertial force at the beginning of the movement will also be large, so that the pallet tends to remain at the initial position of the belt and slips backwards.

Therefore, there is a possibility that the work pallet P will not be able to reach the predetermined station S because the excess tact feeding cannot absorb this backward distance.

The technical problem of the present invention is to shorten the takt time, eliminate positional displacement of workpieces due to stop impact, improve productivity in assembly line operations, and simplify the structure of the conveyance device.

<Means for Solving the Problems> Means for achieving the above-mentioned problems will be explained below using FIGS. 1 to 6, which correspond to embodiments.

That is, in the present invention, each workpiece pallet P is provided with a transportation clamp 7, an unclamping device 8, an unclamp holding device 9, and a positioning engagement portion 10, and the transportation belt 6 of the assembly tact transportation device 1 is made of a metal material. Then, the unclamp release operating device 11 is placed at the transport start station S ₀ of the assembly tact transport device 1.
Each mechanical work station S _K is provided with an unclamp operating device 12 and a positioning engagement operating device 13, and the conveyance terminal station Sn is provided with an unclamp holding operating device 14.
is configured to release the unclamp holding device 9 to fix the transporting clamp 7 to the metal material transporting band 6, and the unclamp operating device 12 operates the unclamping device 8 to fix the transporting clamp 7 to the metal material transporting band 6. The positioning engagement operating device 13 is configured to engage with the positioning engagement portion 10 to position and stop the workpiece pallet P at the mechanical work station S _K ,
The unclamp holding operation device 14 is characterized in that it is configured to operate the unclamp holding device 9 to switch the transporting clamp 7 to an unfixed state and hold it.

<Function> At the transport start station _S0 , the transport clamp 7 fixes the metal material transport main body 6, connects the work pallet P integrally to the transport belt 6, and sets it so that it can be moved along with it. Tact feed to station S.

When each machine work station S _K is reached, the unclamping device 8 operates to release the transport clamps 7 from the transport belt 6, putting the work pallet P in a free state in which it can be independently displaced with respect to the transport belt, and then moving the workpiece pallet P to the positioning member. The work pallet P is positioned at the center of the station S _K using the assembly operation device 13, and mechanical operations such as gluing, assembly, crimping, and iron powder removal are performed in the case of speaker assembly work, for example.

After completing the specified work, move to the transport terminal station Sn.
When the unclamp holding device 9 comes into operation, the conveying clamp 7 is held free from the conveying belt 6.

As a result, the work on the pallet is transferred to the downstream block, and the empty pallet P is returned to the return transport device 3 by the unloading transfer device 2.
Furthermore, it is circulated by the loading transfer device 4 to the original assembly tact transfer device 1.

<Effects of the Invention> (1) Since the conveyance belt is made of a metal material, it does not absorb moisture and expand, and there is no need to carry out excess tact feeding and position the work pallet using a positioning means.

Moreover, since the work pallet is integrally connected to the conveyance belt by the conveyance clamp, even if the conveyance speed is increased, the work pallet reliably moves along with the conveyance belt and does not slip on the conveyance belt.

Therefore, there is no need to set the takt feed length to be longer than the distance between each station as in the past, and there is no pallet slippage due to increased conveyance speed, so takt time can be shortened and production can be improved. You can smoothly improve your sexuality.

(2) Since the tact feed length can be made equal to the distance between each station, as shown in Figure 6, when the station is reached, the speed is zero (refer to the appropriate tact feed curve A), and the positioning means Compared to conventional technology that catches work pallets during transportation, it eliminates the impact of stopping.

Therefore, positional deviation of the workpiece relative to the workpiece pallet is eliminated, and accurate assembly work can be performed.

(3) Since the work pallet fixed to the conveyance belt is accurately positioned at the center of each station, there is no need for conventional work pallet positioning means, and the structure of the tact conveyance apparatus can be simplified.

<Example> Hereinafter, an example of the present invention will be described based on the drawings.

Fig. 1 is a plan view of the work pallet, Fig. 2 is a cross-sectional plan view of the main part thereof, Fig. 3 is a longitudinal sectional front view of the main part of the work pallet around the transportation clamp, Fig. 4 is a longitudinal cross-sectional view of the entire pallet, Figure 5 is a schematic plan view of the work pallet circulation conveyance equipment for speaker manufacturing, and the work pallet circulation conveyance equipment for speaker manufacture includes an assembly tact conveyance device 1, an unloading transfer device 2, a return conveyance device 3, and a loading transfer device. It consists of a loading device 4.

The above-mentioned assembly tact transfer device 1 connects a chain 6 made of metal material to a drive source 15 via an intermittent drive device 5.
Work pallet P placed on chain 6
is configured to be intermittently transported between each station S in order and stopped.

At this time, the work W on the pallet is assembled while being tact-fed through the assembly tact transport device 1, and then moved to the assembly block on the downstream side, and at the same time, the empty pallet is transferred from the device 2 to 3→4
After that, it is circulated again to the conveying device 1.

The work pallet P is composed of an upper pallet 16 and a lower pallet 17 that are removably fixed together with screws. Two positioning holes 18 are made in the bottom of the upper pallet 16 in a symmetrical manner, and the workpiece is transported to the front side of the lower pallet 17. A belt tightening/releasing device 20 is attached.

The conveyance belt tightening/releasing device 20 houses a conveyance clamp 7 having a dogleg-shaped cross section in a clamp chamber 21 formed on the front bottom surface of the lower pallet 17 so as to be slidable back and forth along two guides 22. The chain 6 can be fastened between the conveying clamp 7 and the support pin 23 protruding into the clamp chamber 21, and the unclamping device 8 holds the clamp 7 in an unclamped state, and the unclamping holding device 9 holds the chain 6 in an unclamped state. The clamp 7 is configured to be fixedly held in an unclamped state.

From the front wall 24 of the lower pallet 17 to the clamp chamber 21
A guide hole 25 is provided through the guide hole 25, and a pin-shaped unclamp device 8 is inserted into the guide hole 25 so as to be slidable back and forth.
A positioning engagement portion 10 for positioning at the center 26 of the station S is formed by cutting off the front wall side open end of the station S into a triangular shape.

A dogleg-shaped unclamp holding device 9 is rotatably supported at the left and right corners of the clamp chamber 21 around a fulcrum 27, and a clamp engagement notch 29 is provided in one long arm 28 of the doglegged shape. A release hole 31 is formed and extends from the front wall 24 to the clamp chamber 21.
The other short arm 30 having a dogleg shape is exposed.

A U-shaped leaf spring 32 is interposed between the long arm 28 and the clamp chamber 21, and the unclamp holding device 9 is moved in the unclamp holding direction (that is, the left unclamp holding device in FIG. 2). Taking device 9 as an example,
(in the direction of arrow C).

In addition, three spring housing chambers 34 are formed in the rear end wall 33 of the conveying clamp 7, and the compression springs 35 are housed in the housing chambers 34, so that the conveying clamp 7 is moved forward ( That is, it is elastically biased (in the direction of arrow D in FIG. 2).

On the other hand, as shown in FIG. 4, one of the two chains 6 for tact feeding the work pallet P is a normal chain, and the other is a chain with an attachment 36, and this attachment 36 is connected to the conveying clamp 7. When the attachments are fastened, the work pallet P is tact-fed together with the chain 6, and when the attachment is unclamped, the work pallet P is released from the chain 6 and becomes capable of relative displacement.

The functions of the circulation conveyance equipment for speaker manufacturing of this embodiment will be described below.

(1) Work pallet P is at transport start station S ₀
When the unclamp release operation device 11 is activated, two release pins 37 projecting forward are inserted into the release hole 31 formed in the front wall 24 of the work pallet P.
and rotate the unclamp holding device 9 in the unclamping direction E.

At this time, the conveying clamp 7 is disengaged from the clamp engaging notch 29 of the unclamp holding device and is pushed back in the direction of arrow D by the action of the elastic spring 35, and fastens the attachment 36 of the chain 6 (see FIG. The left half shows the clamped state of the transport clamp 7, and the right half shows the unclamped state.) As a result, the work pallet P on which the work W is placed
is intermittently conveyed integrally with the chain 6, and is stopped every time it is tact-fed to each station S (consisting of a work station where mechanical or manual work is performed and a free station where no work is performed).

Therefore, the conveyor belt 6 is constructed of a metal chain that does not expand or contract due to moisture, etc., and the work pallet P is integrally fixed to the chain 6 and conveyed intermittently, so that the tact feed length is shortened due to moisture absorption. It is not necessary to take the length L ₁ to account for the surplus unlike in the prior art using a belt made of rubber that extends, and it can be shortened to a length equal to the gap L ₀ between the stations S.

(2) Work pallet P is a mechanical work station
When reaching S _K , the tact feed is stopped and at the same time the unclamping operation device 12 is activated, and one unclamping pin 38 protruding forward is inserted into the unclamping device 8 which is slidably inserted into the workpiece pallet P. Press.

The unclamping device 8 pushes the transporting clamp 7 in the direction of the arrow F against the elastic force of the elastic spring 35 to unfasten it from the attachment 36 and release the work pallet P from the chain 6 in a free state.

The tip of the unclamping pin 38 is processed into a triangular shape so that it can engage with the positioning engagement portion 10 of the work pallet P, and the unclamping operation device 12 is also used as the positioning and engagement operation device 13.

Therefore, when the unclamp pin 38 is pressed to the positioning engagement part 10 and engaged, the work pallet P is released from the chain 6 as described above, and the engagement operation device 13 moves the workpiece pallet P to the mechanical work station. Precisely positioned at the center 26 of S _K , gluing, crimping, caulking,
Enables proper mechanical work such as assembly.

(3) For example, in the case of circulation equipment for field part assembly work, when the workpiece pallet P arrives at the transport terminal station Sn after completing the assembly of a given field part,
The unclamp holding operating device 14 is activated, and one holding pin 39 protruding forward presses the unclamping device 8 deeper than the unclamping operating device 12.

As a result, the transporting clamp 7 moves greatly within the clamp chamber 21 in the direction of arrow F, engages with the clamp engagement notch 29 of the unclamp holding device 9 which is rotationally biased in the direction of arrow C, and unclamps. It is held fixed in the state.

As a result, the work pallet P is released from the chain 6 and the work W placed on the pallet P is moved by the inter-block transfer device to the downstream block, specifically, to the front half assembly block of the vibrating section. do.

Further, the empty pallet is returned to the return transport device 3 by the unloading transfer device 2, and returned to the assembly tact transport device 1 by the loading transfer device 4.

As described above, the present invention can shorten the tact feed length and improve productivity, so it can be used not only for manufacturing speakers, but also for home appliances such as watches, telephones, and water heaters. The present invention can be applied to any product, such as automobile parts, that can be manufactured using a tact system assembly line using work pallets.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a plan view of a work pallet, FIG. 2 is a cross-sectional plan view of the main part thereof, FIG. 3 is a vertical cross-sectional front view of the main part of the work pallet around the transportation clamp, and FIG. 5 is a schematic plan view of the work pallet circulation conveyance equipment, and FIG. 6 is a diagram showing the relationship between tact feed length and speed of the conveyance device. 1... Assembly tact transfer device, 2... Unloading transfer device, 3... Return transfer device, 4... Loading transfer device,
5... Intermittent drive device, 6... Conveyance band, 7... Conveyance clamp, 8... Unclamp device, 9... Unclamp holding device, 10... Positioning engagement portion, 11... Unclamp release operation device, 12... Unclamp operation Device, 13... Positioning engagement operating device, 14... Unclamp holding operating device, P... Work pallet, S...
Station, S ₀ ... Transport start station, S _K
...Mechanical work station, Sn...Transfer terminal station.

Claims (1)

[Claims] 1 A large number of work pallets P are transferred from the assembly tact transport device 1 to the unloading transfer device 2 and the return transport device 3
The assembly tact transfer device 1 drives the conveyance belt 6 intermittently with the intermittent drive device 5, so that the work pallets are transported in a circular manner through the loading transfer device 4 and then to the assembly tact transfer device 1. In a tact system-type work pallet circulation conveyance facility for assembly line operations configured to intermittently convey pallets P between stations S in sequence and then stop, each workpiece pallet P is equipped with a conveyance clamp 7, an unclamp device 8, and an unclamp holding device. The apparatus 9 and the positioning engagement part 10 are provided, the conveyance belt 6 of the assembly tact conveyance apparatus 1 is made of metal material, and the unclamp release operation device 11 is provided at the conveyance start end station _S0 of the assembly tact conveyance apparatus 1. Each machine work station
An unclamp operating device 12 and a positioning engagement operating device 13 are provided at S _K , and an unclamp holding operating device 14 is provided at the transport end station Sn. The unclamp operation device 12 is configured to operate the unclamp device 8 to release the transportation clamp 7 from the metal material conveyance band 6. and positioning engagement operation device 13
is configured to engage with the positioning engagement portion 10 to position and stop the work pallet P on the mechanical work station S _K , and the unclamp holding operation device 14 operates the unclamp holding device 9 to release the transport clamp 7. A tact system-type work pallet circulation conveyance equipment for assembly line work, characterized in that the work pallet circulation conveyance equipment is configured to switch to an unfixed state and hold the work pallets.