Air bag cover body forming apparatus

The present invention relates to an air bag cover forming apparatus. The “air bag cover” described in the present invention is utilized for covering an air bag device in a vehicle such as a car. The typical example of an air bag cover is an instrument panel.

Generally, an air bag device for the passenger seat is attached inside of an instrument panel. Conventional attaching mechanisms for air bag device are disclosed in JP-A-2001-39254 and JP-A-2001-47959, for example.

FIG. 16 is a schematic view illustrating an example of conventional instrument panel (indicated by reference number 1 ). FIG. 17 illustrates an air bag device 8 attached inside the instrument panel 1 . The instrument panel is made of resin and formed with an air bag door 10 facing the air bag device 8 . The rear side of the instrument panel 1 is formed with a plurality of grooves defining the air bag door 10 . As shown in FIG. 16 , the grooves 11 include three grooves 11 a - 11 c extending longitudinally of the instrument panel 1 and two grooves 11 d, 11 e extending perpendicularly to the three longitudinal grooves. The portions formed with the grooves are weaker than the other portions of the instrument panel 1 . With such an arrangement, when the air bag (not shown) of the air bag device 8 inflates, the portions formed with the grooves 11 are broken due to the pressure by the air bag. As a result, as shown by the phantom lines in FIG. 17 , the air bag door 10 is opened and the air bag comes out of the instrument panel 1 .

It is desirable that the air bag door 10 is designed to be prevented from flying into pieces when the air bag door 10 opens. To achieve this, the air bag door 10 is supported by a retainer 80 , for example. The retainer 80 is made of a bendable metal plate, and includes an end attached to the air bag device 8 . The other end of the retainer 80 is fixed to a rib 13 formed at the rear side of the air bag door 10 . Due to this structure, the air bag door 10 is prevented from flying into pieces by the retainer 80 when the air bag door 10 opens.

The instrument panel 1 may be molded from resin material utilizing a molding apparatus B as shown in FIG. 18 . The molding apparatus B includes an upper portion 7 A, a lower portion 7 B, and a plurality of grooving blades 39 . The upper portion 7 A and the lower portion 7 B form a cavity 70 for molding the instrument panel 1 . Each grooving blade includes a tip end inserted into the cavity 70 for forming the break grooves 11 at the instrument panel 1 . Though it is not shown in FIG. 18 , the grooving blade 39 is a rectangular plate. The base ends of the grooving blades 39 are connected to each other.

After the instrument panel 1 is molded in the cavity 70 , the upper portion 7 A and the lower portion 7 B are separated. (JP-A-11-34124 discloses an example of an apparatus for reciprocally moving a mold for resin molding within a predetermined area.) Then, the instrument panel 1 is taken out of the mold.

However, in the prior art, as described below, the instrument panel may not be taken out properly from the mold.

When the instrument panel 1 is taken out from the lower portion 7 B, the air bag door 10 tends to remain in the mold more often than the other portions. One cause of this is the ribs 13 formed at the air bag door 10 . As the ribs 13 increase the contacting area of the air bag door 10 and the lower portion 7 B, the air bag door 10 is not easily separated from the lower portion 7 B. If the instrument panel 1 is forcibly pulled to be separated from the lower portion 7 B when the air bag door 10 intimately contacts with the lower portion 7 B, the weak portions formed with the break groove 11 may be bent or damaged. Further, the bent break groove 11 may be whitened.

The present invention has been proposed under the above-described circumstances. It is therefore an object of the present invention to provide a forming apparatus designed to prevent concentration of too much stress on a break groove formed at a resin molded body.

According to the present invention, there is provided an apparatus for forming an air bag cover. The forming apparatus comprises a mold for forming a cavity in which a resin air bag cover having an air bag door is molded, a grooving blade for forming a break groove defining the air bag door at the air bag cover and a supporting member for supporting the air bag door of the air bag cover molded in the cavity. The apparatus includes a movable core reciprocally movable in a first reciprocal direction parallel to a line connecting a position where the core contacts the air bag cover and a position where the core is separated from the air bag cover. The supporting member comes into supporting contact with the air bag door when the core is separated from the air bag door.

Preferably, the supporting member is a rod extending through the movable core.

Preferably, the movable core includes a recess for forming a rib at the air bag door, and the supporting member contacts with the air bag door at a portion adjacent to the rib.

Preferably, the forming apparatus of the present invention further comprises a follower block connected to the movable core and reciprocally movable in the first reciprocal direction, a drive block contacting the follower block and first drive source for reciprocally moving the drive block along a second reciprocal direction perpendicular to the first reciprocal direction. The follower block is moved in the first reciprocal direction by the movement of the drive block in the second reciprocal direction.

Preferably, at least one of the drive block and the follower block is formed with an inclined cam surface for moving the follower block in the first reciprocal direction.

Preferably, the drive block is formed with an inclined cam surface for moving the follower block in the first reciprocal direction and also formed with a pressure receiving surface which is next to the inclined cam surface and is parallel to the second reciprocal direction.

Preferably, the follower block is formed with an inclined cam surface which is brought into contact with the inclined cam surface of the drive block and also formed with a plan surface which is next to the inclined cam surface of the follower block and is brought into contact with the pressure receiving surface of the drive block.

Preferably, the molding apparatus according to the present invention further comprises a link for connecting the drive block and the follower block. The link pulls the follower block away from the air bag door in accordance with the movement of the drive block.

Preferably, the link includes a first end and a second end spaced from each other. The first end rotatably is attached to the drive block, while the second end projects into a recess formed in the follower block.

Preferably, the forming apparatus of the present invention further comprises a second drive source for moving the grooving blade in the first reciprocal direction. The second drive source moves the grooving blade between a position to be inserted in the cavity and a position to be moved out of the cavity.

Preferably, the mold includes an upper portion and a lower portion for working together to form the cavity. The lower portion includes a support body and an auxiliary block removable from the body, and the auxiliary block is formed with a space for movably incorporating the grooving blade in the first reciprocal direction. The second drive source is provided at the support body.

Preferably, the space of the auxiliary block further accommodates the follower block and the drive bock, and the first drive source is provided at the support body.

Preferably, the first drive source is connected to the drive block via a connecting rod removably attached to the drive block, while the second drive source is connected to the grooving blade via another connecting rod removably attached to the grooving blade.

Preferably, the molding apparatus according to the present invention further comprises a cooling means for cooling the movable core.

Preferably, the cooling means includes a duct provided in the movable core through which cooling medium passes.

Preferably, the cooling means further includes another duct which is provided in the follower block and connected to the duct in the movable core.

FIG. 1 is a section view illustrating a principal part of a molding apparatus according to a first embodiment of the present invention.

FIG. 2 is a view illustrating the function of a drive block and a follower block of the molding apparatus according to the first embodiment.

FIG. 3 is a plan view illustrating a principal part of the lower portion of the molding apparatus according to the first embodiment.

FIG. 4 is a section view illustrating the function of the lower portion of the molding apparatus according to the first embodiment.

FIG. 5 is a view illustrating a principal part of a molding apparatus according to a second embodiment of the present invention.

FIG. 6 is a view illustrating a principal part of a lower portion of the molding apparatus according to the second embodiment of the present invention.

FIG. 7 is a section view illustrating the structure of a link for connecting a drive block and a follower block according to the second embodiment, taken along lines X 7 -X 7 in FIG. 5 .

FIG. 8 illustrates the drive block, follower block, and link according to the second embodiment.

FIG. 9 is a section view illustrating the lower portion of the molding apparatus according to the second embodiment.

FIG. 10 is a view illustrating a principal part of a molding apparatus according to a third embodiment of the present invention.

FIG. 11 is a section view illustrating a principal part of a lower portion according to the third embodiment.

FIG. 12 is a plan view illustrating a principal part of the lower portion according to the third embodiment.

FIGS. 13 and 14 are views illustrating a principal part of a molding apparatus according to a fourth embodiment of the present invention.

FIG. 15 is a view illustrating the advantageous effect of a lower portion of the molding apparatus according to the fourth embodiment.

FIG. 16 is a schematic view illustrating an example of conventional instrument panel.

FIG. 17 is a section view taken along lines X 17 -X 17 in FIG. 16 .

FIG. 18 is a section view illustrating a principal part of a conventional molding apparatus.

Preferred embodiments of the present invention are described below with reference to the drawings.

FIGS. 1-3 illustrate a molding apparatus A 1 according to a first embodiment of the present invention. The molding apparatus A 1 is used to mold the above-described conventional instrument panel 1 (refer to FIGS. 16-18 ).

As shown in FIGS. 1 and 2 , the molding apparatus A 1 includes a mold having an upper portion 2 A and a lower portion 2 B. The molding apparatus A 1 further includes a plurality of grooving blades 3 and supporting rods 4 .

The upper portion 2 A and the lower portion 2 B move toward and away from each other. In the illustrated example, only the upper portion 2 A is movable while the lower portion 2 B is immovable. The upper portion 2 A moves, for example, horizontally or vertically. The upper portion 2 A and the lower portion 2 B are clamped to form a cavity 20 for molding the instrument panel 1 . The lower portion 2 B includes two movable cores 21 a, 21 b.

The grooving blades 3 include tip ends inserted into the cavity 20 to form a plurality of break grooves 11 . The grooving blades 3 are metal plates connected to each other to form a rectangle corresponding to the break grooves 11 , as viewed in plane (refer to FIG. 3 ). The grooving blades 3 further include bases connected to each other via a connecting member 30 . The grooving blades 3 are movable toward the cavity 20 and in the opposite direction (a direction N 1 ) by a drive source having a reciprocating cylinder for example. With such an arrangement, the tip end of the grooving blade 3 can be moved out of the cavity 20 when the cavity 20 is filled with melted resin. As a result, resin can smoothly flow into all portions of the cavity 20 . The tip end of the grooving blades 3 are inserted into the cavity 20 after the cavity 20 is filled with resin and before the resin is hardened. In this way, the break groove 11 is formed at the instrument panel 1 . Differently from the illustrated example, the grooving blade 3 may be immovable in the direction N 1 . In this case, the tip end of the grooving blade 3 remains being inserted in the cavity 20 .

The supporting rods 4 are made of metal and extend to penetrate thicknesswise of the connecting member 30 of the grooving blade 3 as well as the cores 21 a, 21 b of the lower portion 2 B. The supporting rods 4 are fixed at portions below the lower portion 2 B. Each supporting rod 4 includes a top surface partly forming the surface of the cavity 20 . Thus, as shown in FIG. 1 , the top surface of the supporting rod 4 contacts a lower surface 12 of an air bag door 10 formed in the cavity 20 .

Specifically, the cores 21 a, 21 b of the lower portion 2 B are formed with a plurality of recesses 22 for forming a plurality of ribs 13 to which retainers are attached. As shown in FIG. 3 , the recesses 22 are arranged in two rows and properly spaced to each other in a direction N 3 (the longitudinal direction of the cavity 20 or the instrument panel 1 ). In the example shown in FIG. 3 , eight connecting rods 4 are used in total. Each rod 4 is arranged adjacent to one or two recesses 22 .

The cores 21 a, 21 b of the lower portion 2 B form the lower surface 12 of the air bag door 10 . The cores 21 a, 21 b are formed separately from the other parts of the lower portion 2 B, and are surrounded by the grooving blades 3 . The cores 21 a, 21 b are movable slidably relative to the connecting rod 4 and also movable reciprocally in the longitudinal direction (the direction N 1 ) of the connecting rod. A mechanism used for the reciprocal movement, as shown in FIG. 2 , includes a drive block 41 , a follower block 42 , a drive source 40 such as a hydraulic reciprocating cylinder. The drive block 41 is connected to the drive source 40 via a rod 40 a and is reciprocally movable by the drive source 40 in a direction N 2 on a base 44 . The drive block 41 and the follower block 42 include inclined surfaces 41 a, 42 a slidable to each other. According to the reciprocal movement of the drive block 41 in the direction N 2 , the follower block 42 moves up and down in the direction N 1 . The two cores 21 a, 21 b are connected to the follower block 42 via connecting rods 29 and move up and down according to the movement of the follower block 42 .

When the cavity 20 is filled with resin to form the instrument panel 1 , the cores 21 a, 21 b are subjected to downward pressure in the direction N 1 . In the mechanism shown in FIG. 2 , the applied pressure is supported by the drive block 41 . As a result, the drive source 40 needs not to support the pressure directly, whereby the drive source 40 can be downsized.

Next, the function of the molding apparatus A 1 is described below.

First, as shown in FIGS. 1 and 2 , the cavity 20 formed by the upper portion 2 A and the lower portion 2 B is filled with resin to mold the instrument panel 1 . Next, the upper portion 2 A is lifted to move away from the lower portion 2 B. Then, as shown in FIG. 4 , the cores 21 a, 21 b of the lower portion 2 B move downward in the direction N 1 . Specifically, as shown in FIG. 2 , the drive source 40 moves the drive block 41 toward the left side in the direction N 2 . Due to this movement, the cores 21 a, 21 b (and the follower block 42 ) are moved downward in the direction N 1 by the gravitational force.

The recesses 22 for forming the ribs 13 of the air bag door 10 are formed at the cores 21 a, 21 b. Thus, the downward movement of the cores 21 a, 21 b generates downward force to move the air bag door 10 together with the cores 21 a, 21 b. On the other hand, the supporting rods 4 contacting the air bag door 10 prevent the downward movement of the air bag door 10 . Since the supporting rods 4 are immovable, the air bag door 10 is not lifted relative to the other portions of the instrument panel 1 .

In this way, the air bag door 10 and the cores 21 a, 21 b can be properly separated without applying large stress concentration on the portions where the break grooves 11 of the instrument panel 1 are formed. Further, due to the connecting rods 4 arranged adjacent to the recesses 22 (or the ribs 13 ), the portion formed with the break grooves 11 does not receive much force applied when the air bag door 10 and the cores 21 a, 21 bi are separated.

If the cores 21 a, 21 b are very intimately fixed to the air bag door 10 , the follower block 42 and the cores 21 a, 21 b may not be lowered only by the gravitational force even the drive block 41 is moved toward the drive source 40 . In this case, a proper auxiliary means may be preferably provided for forcibly pulling down the follower block 42 (refer to the second embodiment).

After the cores 21 a, 21 b are lowered as described above, the instrument panel 1 is taken out of the lower portion 2 B. Similarly to a general metal molding apparatus, the lower portion 2 B is provided with a plurality of extruding pins (not shown) at the portions other than the cores 21 a, 21 b for extruding a molded piece. The extruding pins are used to press the instrument panel 1 at the portions other than the air bag door 10 , so that the instrument panel 1 is taken out of the lower portion 2 B. It is not difficult to provide the extruding pins reciprocally movable at the portions where the cores 21 a, 21 b and the grooving blades 3 are not formed, or at the portions which do not contact the air bag door 10 of the instrument panel 1 . When the extruding pins press out the instrument panel 1 , the air bag door 10 and the cores 21 a, 21 b are already separated. In this state, different from the conventional art, the pressing force of the extruding pins is not concentrated on the break groove 11 . As a result, the instrument panel 1 can be properly taken out without whitening or damaging the break groove 11 .

FIGS. 5-9 illustrate a molding apparatus A 2 according to a second embodiment of the present invention. As seen from comparison between FIG. 5 and FIG. 2 and between FIG. 6 and FIG. 1 , the molding apparatus A 2 according to the second embodiment has a structure essentially similar to the molding apparatus A 1 of the first embodiment, and thus has effect similar to the molding apparatus A 1 .

Specifically, as shown in FIG. 5 , the molding apparatus A 2 includes a mold having an upper portion 2 A and a lower portion 2 B and also includes a plurality of grooving blades 3 . Further, as shown in FIG. 6 , the molding apparatus A 2 includes a plurality of supporting rods 4 for contacting with a molded instrument panel 1 . The upper portion 2 A is movable toward and away from the lower portion 2 B. The upper portion 2 A and the lower portion 2 B form a cavity 20 for molding the instrument panel 1 . The lower portion 2 B includes two movable cores 21 a, 21 b. The grooving blades 3 are inserted into the cavity 20 to form a plurality of break grooves 11 at the instrument panel 1 . The grooving blades 3 are connected to each other via a connecting member 30 . The supporting rods 4 , as shown in FIG. 6 , extend to penetrate the connecting member 30 and the cores 21 a, 21 b of the lower portion 2 B.

The cores 21 a, 21 b of the lower portion 2 B are formed with a plurality of recesses 22 for forming ribs 13 . The cores 21 a, 21 b are movable slidably relative to the supporting rods 4 and also movable reciprocally in the direction N 1 (refer to FIGS. 6 and 9 ). A mechanism used for the reciprocal movement, as shown in FIG. 5 , includes a drive block 41 , a follower block 42 , a drive source 40 such as a hydraulic reciprocating cylinder. The drive block 41 is connected to the drive source 40 via a rod 40 a and is reciprocally movable by the drive source 40 in the direction N 2 on a base 44 .

Similarly to the first embodiment, in the above-described molding apparatus A 2 of the second invention, the supporting rods 4 contact with the instrument panel 1 molded in the cavity 20 . Thus, as shown in FIG. 9 , when the cores 21 a, 21 b are lowered, the supporting rods 4 prevent the downward movement of the air bag door 10 . As a result, the air bag door 10 and the cores 21 a, 21 b can be separated without applying a large load on the break groove 11 of the instrument panel 1 .

Next, different points between the molding apparatus A 2 of the second embodiment and the molding apparatus A 1 of the first embodiment are described below.

Specifically, the molding apparatus A 2 differs from the molding apparatus A 1 in the structure of the drive block 41 and the follower block 42 . As shown in FIG. 5 , the top surface of the drive block 41 is formed with steps thicknesswise (the direction N 1 ) of the drive block 41 . This step-like top surface includes a plurality of cam surfaces 45 a and pressure receiving surfaces 46 a arranged alternately in the direction N 2 . On the other hand, the bottom surface of the follower block 42 is formed with steps and includes a plurality of cam surfaces 45 b and plan surfaces 46 b arranged alternately, corresponding to the top surface of the drive block 41 .

The cam surfaces 45 a are inclined surfaces for lifting up the follower block 42 when the drive block 41 advances in the direction indicated as N 2 a in FIG. 5 . The inclined angle (<90°) of the surface is e.g. 45 degrees or smaller relative to the direction N 2 . The cam surface 45 b of the follower block 42 is an inclined surface parallel or substantially parallel to the cam surface 45 a. The pressure receiving surface 46 a of the drive block is a plan surface for receiving a load from the follower block 42 when the vertical movement of the follower block 42 is stopped. The pressure receiving surface 46 a is inclined at an angle of zero or substantially zero relative to the direction N 2 . The plan surface 46 b of the follower block 42 is parallel or substantially parallel to the pressure receiving surface 46 a.

The drive block 41 and the follower block 42 are connected to each other via a link 43 . As shown in FIG. 7 , the link 43 includes a bottom end 43 a rotatably attached to the drive block 41 via a shaft 47 . The link 43 further includes a top end 43 b formed with a protrusion 49 . The protrusion 49 engages with a recess 48 formed at the side surface of the follower block 42 . As shown in FIG. 5 , the recess 48 is designed to have a form and a size for allowing the protrusion 49 to play moderately in the directions N 1 and N 2 . When the drive block 41 shifts in a direction N 2 b at more than a predetermined distance, the protrusion 49 engages with a wall 48 a defining the recess 48 , whereby the follower block 42 is pulled down by the link 43 .

Next, the function of the drive block 41 and the follower block 42 of the molding apparatus A 2 is described below.

First, as shown in FIG. 5 , each pressure receiving surface 46 a of the drive block 41 contacts respective plan surface 46 b of the follower block 42 when the instrument panel 1 is molded in the cavity 20 of the mold. In this way, the downward movement of the follower block 42 is prevented and the cores 21 a, 21 b are not pressed downward by the pressure from the cavity 20 . Since the pressure receiving surface 46 a is not inclined relative to the direction N 2 , the pressing force F from the follower block 42 does not apply a large component force in the direction N 2 . Thus, all or almost all of the pressing force F can be supported by the base 44 . As a result, the pressing force F is not applied directly to the drive source 40 , and hence the drive source 40 can be downsized.

The instrument panel 1 is taken out in a step similar to the first embodiment after the instrument panel 1 is molded. Specifically, the upper portion 2 A is lifted to open the mold. Next, the drive source 40 is driven to lower the cores 21 a, 21 b of the lower portion 2 B as shown in FIG. 8 . This downward movement is performed by shifting the drive block 41 in the direction N 2 b in FIG. 8 , so that the follower block 42 is lowered due to the gravitational force. If the follower block 42 can not be lowered only by the gravitational force (if the cores 21 a, 21 b is fixed intimately to the instrument panel 1 ), the link 43 rotatably attached to the drive source 41 pulls and forcibly lowers the follower block 42 .

After the instrument panel 1 is taken out, the cores 21 a, 21 b are moved upward to return to the initial position. This movement is performed by shifting the drive block 41 in the direction N 2 a at a proper distance by the drive source 40 . When the drive block 41 advances, each of the inclined cam surfaces 45 a slidably contacts with a respective cam surface 45 b, whereby the follower block 42 is lifted up.

FIGS. 10-12 illustrate a molding apparatus A 3 according to a third embodiment of the present invention.

As seen from the comparison between FIGS. 10 and 5 as well as between FIGS. 11 and 6 , the molding apparatus A 3 according to the third embodiment has a structure substantially similar to the molding apparatus A 2 according to the second embodiment. Thus, the molding apparatus A 3 has an effect similar to the molding apparatus A 2 as described above.

The molding apparatus A 3 according to the third embodiment differs from the molding apparatus A 2 according to the second embodiment in having a cooling means for cooling the cores 21 a, 21 b.

As shown in FIG. 10 , the cooling means according to the third embodiment includes a cooling water supplier 50 , a pipe 51 , and a cooling water path 5 . The cooling water supplier 50 is provided outside of the upper portion A and lower portion 2 B. The pipe 51 connects the cooling water supplier 50 to the cooling water path 5 . The cooling water path 5 extends inside of the follower block 42 , connecting rods 29 , and cores 21 a, 21 b. The pipe 51 includes a flexible end connected to the follower block 42 . Due to this structure, the follower block 42 can shift in the direction N 1 without regulation by the pipe 51 .

The cooling water path 5 includes a duct 5 a provided at the follower block 42 , a duct 5 b provided at each connecting rod 29 , and a duct 5 c provided at each of the cores 21 a, 21 b. The ducts 5 a - 5 c are connected in series. As shown in FIG. 12 , the cores 21 a, 21 b are rectangular. The duct 5 c extends longitudinally of the core so that a wide area of the core is cooled effectively. The cooling water passed through the duct 5 c is discharged out of the mold via a non-illustrated duct.

Next, the function of the cooling means of the molding apparatus A 3 is described below.

First, similarly to the first and second embodiments, the cavity 20 formed by the upper portion 2 A and the lower portion 2 B is filled with resin to mold the instrument panel 1 . In the third embodiment, cooling water passes through the cooling water path 5 during the resin filling in the cavity 20 . In this way, the cores 21 a, 21 b are cooled by the cooling water to reduce the thermal expansion rate of the cores 21 a, 21 b. As a result, the grooving blade 3 can be protected from damage or defective movement due to the thermal expansion of the cores 21 a, 21 b, more effective than in the apparatus without the cooling means. Here, the defective movement of the grooving blade 3 indicated the situation in which the grooving blade 3 is prevented from shifting in the direction N 1 by the cores under thermal expansion.

There is another advantage in the cooling of the cores 21 a, 21 b. If the temperature rise at the cores 21 a, 21 b can be regulated, the portion formed to be the air bag door 10 is cooled and hardened in a relatively short time after the resin filling in the cavity 20 . As a result, contraction rate of resin in this portion is reduced, whereby clumsy contraction in volume is less caused in the air bag door 10 .

The cooling means for cooling the cores is not limited to the example shown in the drawings. For example, the cores may be cooled by a cooling medium brought into contact with the outer surface of the cores (other than the portions facing the cavity). The cooling medium is not limited to cold water, but other medium can be utilized.

FIGS. 13-15 illustrate a molding apparatus A 4 according to a fourth embodiment of the present invention.

As shown in FIG. 13 , the molding apparatus A 4 includes an upper portion 2 A, a lower portion 2 B, a plurality of grooving blades 3 , a drive block 41 , a follower block 42 , a first drive source 40 , and a second drive source 40 ′.

The upper portion 2 A is reciprocally movable in the horizontal direction indicated by Nd, and works together with the lower portion 2 B to form a cavity 20 . The lower portion 2 B includes a replaceable auxiliary block 26 and a body 27 supporting the block 26 . The block 26 is formed with a space 25 in which the grooving blades 3 and other members are incorporated.

The block 26 includes a surface 26 a for molding a surface at and around the air bag door 10 of the instrument panel 1 . The body 27 includes a surface 27 a for molding a surface of the other portions of the instrument panel 1 , and a space 27 b for fixing the block 26 therein. The space 27 b is defined by a vertical wall 27 c and a horizontal wall 27 d. The block 26 includes a side surface 26 c and a bottom surface 26 d, respectively contacting to the wall 27 c and the vertical wall 27 d, and fixed to the body 27 . A bolting means (not shown), for example, may be utilized for the fixation.

Similarly to the above-described first to third embodiments, the lower portion 2 B according to the fourth embodiment includes movable cores 21 a, 21 b for molding a surface of the air bag door 10 . The cores 21 a, 21 b are connected to the follower block 42 via connecting rods 29 . Similarly to the molding apparatuses according to the second and third embodiments, the drive block 41 is moved in a direction N 2 by the first drive source 40 , whereby the follower block 42 shifts in a direction N 1 . However, in the fourth embodiment, a link (refer to the reference number 43 in FIG. 5 or 10 ) is not used for connecting the drive block 41 and the follower block 42 . Of course, the present invention is not limited to this example but the link 43 may be used also in the fourth embodiment. As shown in FIG. 14 , the first drive source 40 is provided at a space 27 f formed in the body 27 .

The grooving blades 3 include tip ends reciprocally movable in and out of the cavity 20 . The grooving blades 3 further include bottom ends connected to each other via a connecting member 30 . The grooving blade 3 is connected to the second drive source 40 ′ via a rod 40 a ′. The second drive source 40 ′ is e.g. hydraulic cylinder for reciprocally moving the grooving blade 3 in the N 1 direction. The drive source 40 ′ is provided at a space 27 e formed in the body 27 . The rod 40 a ′ includes a tip end removably attached to the connecting member 30 . The space 25 includes inner walls serving as guide surfaces for the reciprocal movement of the grooving blade 3 . Threaded engagement may be applied for the removable attachment of the tip end of the rod 40 a ′ to the connecting member 30 , by providing male and female screws. The above-described drive block 41 is also removably attached to a rod 40 a by such threaded engagement.

Next, the function of the molding apparatus A 4 is described below.

As shown in FIGS. 13 and 14 , the cavity 20 formed by the upper portion 2 A and the lower portion 2 B is filled with resin to mold the instrument panel 1 . During the resin filling, the second drive source 40 ′ is driven to lower the grooving blade 3 so that the tip end is not inserted into the cavity 20 . Then, before the filled resin is hardened, the grooving blade 3 is inserted into the cavity 20 to form the break groove 11 .

After molding of the instrument panel 1 is finished, the instrument panel 1 is taken out of the mold. Specifically, the upper portion 2 A is moved toward the right side in the Nd direction to open the mold, and the drive source 40 is driven to lower the cores 21 a, 21 b. A connecting rod (refer to the reference number 4 in FIG. 11 ) is provided also in the fourth embodiment in a contacting manner with the air bag door 10 of the instrument panel. Due to the structure, the air bag door 10 is prevented from lowering together with the cores 21 a, 21 b.

As shown in FIG. 15 , the auxiliary block 26 of the lower portion 2 B can be removed from the body 27 . This structure is convenient when the block 26 is to be repaired. The movable members (cores 21 a, 21 b, grooving blades 3 , drive block 41 , and follower block 42 ) incorporated in the space 25 of the block 26 may need to be replaced because of wear, for example. This replacement can be facilitated by removing the block 26 from the body 27 . If the lower portion 2 B is formed as an integrated member, differently from this embodiment, the entire lower portion 2 B needs to be replaced or repaired even only the portion corresponding to the block 26 is damaged. However, in the molding apparatus A 4 according to the present invention, only the block 26 needs to be replaced or repaired.

In making the lower portion 2 B, separately made block 26 and body 27 are assembled. In forming the space 25 in the block 26 , the space 25 may be formed in vertical direction (at an inclined angle of 90°) or in horizontal direction (at an inclined angle of 0°), by accordingly determining the holding position of the block 26 . Generally, it is easier to form a space at an inclined angle of 0° or of 90° than at other angles (0°<inclined angle<90°). Thus, it is advantageous to form the block 26 separately from the body 27 in that the formation of the lower portion 2 B is facilitated.

The present invention being thus described, it is obvious that the same may be modified in various ways. Such modifications should not be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to those skilled in the art are intended to be included in the scope of the appended claims.