JP2005074120A - Air game machine and pack - Google Patents

Abstract

【Task】
An object of the present invention is to provide a simple air game machine having a structure in which a puck is not stationary at the center of a play field board.
[Solution]
In the air game machine 1 having at least two goals 7 and allowing the pack 10 to slide on the playfield board 5 lightly by the air jetted upward from the air ejection holes 6 formed in a large number on the playfield board 5. The air ejection holes 6 are more densely arranged at the center than the other parts of the play field plate 5.
[Selection] Figure 1

Description

  The present invention relates to an air game machine in which a pack is lightly slid on the play field board by air jetted upward from a plurality of air jet holes formed in the play field board, and a pack used in the air game machine. is there.

There has been an air game machine in which the ejection pressure of air ejected from a plurality of air ejection holes formed in the play field board is changed in accordance with the position and time of the play field board.
This air game machine requires an ejection control device for changing the ejection pressure of the air ejected from the air ejection hole in accordance with the position and time of the play field plate, so that the structure is complicated and the cost is increased. In addition, maintenance was required to operate this ejection control device normally.

JP-A-8-71247

  An object of the present invention is to provide a simple air game machine having a structure in which a puck is not stationary at the center of a play field board.

  According to the first aspect of the present invention, there is provided an air game including at least two goals and allowing the pack to easily slide on the play field board by air jetted upward from air jet holes formed in a large number on the play field board. The air game machine is characterized in that the air ejection holes are densely arranged at a central portion as compared with other portions of the play field plate.

  The invention according to claim 2 is an air game having at least two goals and allowing the pack to easily slide on the play field board by air jetted upward from air jet holes formed in a large number on the play field board. In the machine, the left and right side width defining means for defining the maximum goal width fixed to the play field plate, and located closer to the center of the goal width than the left and right side width defining means, approaching the play field plate, Goal width reducing means provided so as to be movable up and down so as to narrow down, a pair of left and right goal width adjusting means provided movably in the width direction of the play field plate, and the pair of goal widths on the left and right sides The pair of left and right goal width reducing means are lifted away from the play field board in the separated state of the adjustment operation means, and the pair of left and right goal width adjustment operations are performed. An air game machine, characterized in that the goal width reduction means of the left and right pair in a close state of the stage equipped and interlock means to reduce the goal width close on the playfield plate.

  According to a third aspect of the present invention, there are provided a plurality of screw rods standing on the base in the vertical direction, and screwed into the screw rods, respectively, and rotatably provided on an upper housing provided with a play field plate. And an elevating drive means for driving the plurality of screw rods or the plurality of female screws simultaneously at the same rotational speed.

  According to a fourth aspect of the present invention, a base frame placed horizontally on a floor surface or the ground, and one end of a pair of left and right elongated members parallel to each other are pivotally attached to one end of the base frame. The longitudinal center of the pair of left and right elongated members on the other supporting leg is pivotally attached to the other supporting leg and the longitudinal center of the pair of left and right elongated members on the other supporting leg. One end of each of the left and right elongated horizontal members of the elevating frame is pivotally attached to the upper end of one pair of left and right elongated members of the other supporting leg, and a play field plate is provided above. And an elevating drive means for changing the interval between the two pairs of support legs or between the base frame and the elevating frame so as to be expandable / reducible, and a pair of left and right elongated members on the one support leg. The upper end of the end side of the left and right elongated members in the lifting frame The lower end of the pair of left and right elongated members on the other supporting leg is horizontally held by the horizontal guide member on the other end side of the base frame. An air game machine characterized in that it is held so as to be freely movable.

  According to a fifth aspect of the present invention, the air game machine has at least two goals, and can easily slide on the play field board by the air jetted upward from the air ejection holes formed in the play field board. In the pack, the pack is integrally coupled to the central boss portion, a plurality of spoke portions that diverge in a radial direction from the outer peripheral surface of the boss portion, and spirally bend, and an outer end portion of the spoke portion. The spoke portion is a pack that is formed in a shape inclined in one direction like a blade of a propeller with respect to a plane orthogonal to the center line of the boss portion.

  According to the sixth aspect of the present invention, the air game machine has at least two goals, and can easily slide on the play field board by air jetted upward from the air jet holes formed in the play field board. In the pack, the approximate shape of the pack is a substantially disk shape, and the central portion of the pack is made of a hard thermoplastic resin having a high softening temperature and high self-lubricity, and the outer peripheral portion of the pack is It is made of a soft thermoplastic resin having a softening temperature lower than that of the pack center portion, and the pack outer peripheral portion made of the soft thermoplastic resin is integrally melt-bonded to the pack center portion made of the hard thermoplastic resin. It is a pack.

  In the first aspect of the present invention, since the arrangement density per unit area of the air ejection holes in the center portion of the playfield plate is higher than that in other portions, the amount of air ejection per unit area in the center portion of the playfield plate Is larger than other parts, the gap between the play field board and the puck is widened, the friction between the play field board and the puck is reduced, and the puck is decelerated and stopped at the center of the play field where the player cannot reach As a result, the player moves away from the vicinity of the goal and moves to either the left or right play field side, and does not hit the puck, so that play is not interrupted and speedy play is performed.

  In the invention according to claim 2, since the goal width can be changed in accordance with the skill of the player, even if the opponent has a difference in skill, the game becomes close and the interest is enhanced. And by visually observing the position of the goal width adjustment operation means, it is possible to know the goal width of the opponent side, so that the distrust that the opponent side goal cannot be scored with an illegal mechanism is eliminated, and the goal result is obtained. The player can be satisfied.

  In the third aspect of the invention, by operating the raising / lowering driving means, the play field plate provided on the upper housing can be moved up and down in accordance with the height of the player while maintaining the horizontal level constantly. The player can enjoy the game with a reasonable posture. Since the upper housing with the play field is driven up and down by screwing the screw rod and the female screw, even if a large force from above to below acts on a part of the upper housing, the upper housing As a result, the play field board never tilts.

  According to the fourth aspect of the present invention, the play field board is moved up and down by operating the elevating drive means so as to enlarge / reduce the distance between the two pairs of support legs or between the base frame and the elevating frame. The height of the playfield board can be quickly and easily adjusted to the height of the player.

  In the invention according to claim 5, the air ejected upward from the air ejection holes formed in a large number in the play field plate hits the spoke portion of the pack on the play field plate, and the pack is formed by the unidirectional inclination of the spoke portion. Can float on the playfield board while rotating in one direction.

  In this way, the puck can float on the play field board while rotating in one direction, so it behaves differently from the puck in the conventional air game machine, so the player plays the game with a different sensation than before. I can enjoy it.

  In the invention according to claim 6, since the center portion of the pack made of hard thermoplastic resin rich in self-lubricating property which occupies most of the pack comes into contact with the play field plate with a low frictional force, the pack is ejected from the air ejection hole. Combined with the air bearing capacity, it can slide more easily on the playfield plate, and the outer periphery of the pack is made of soft thermoplastic resin, and it is integrally melt-bonded to the center of hard thermoplastic resin. Therefore, when the pack collides with the mallet or the wall portion of the outer peripheral portion of the play field plate, the impact force is greatly relaxed and the occurrence of impact noise is suppressed.

  The best mode of the present invention as set forth in claim 1 shown in FIGS. 1 to 5 will be described below.

  In the air hockey game machine 1 which is a kind of air game machine, casters 3 are pivotally attached to the corners of the lower surface 4 of the upper housing 2 around the vertical axis, and extendable legs 4 are respectively provided adjacent to the casters 3. When the telescopic leg 4 is shortened, the air hockey game machine 1 can be freely moved on the floor 0 by the caster 3, and when the telescopic leg 4 is extended, the air hockey game machine 1 is moved by the telescopic leg 4. The play field board 5 of the air hockey game machine 1 is maintained horizontally by being installed on the floor 0 and adjusting the degree of expansion / contraction of the four expansion / contraction legs 4.

  The play field plate 5 has a large number of air ejection holes 6. In the range surrounded by a circle having a radius R with the center of the play field plate 5 as the center, the air ejection holes are compared to other ranges. 6 is doubled in length units and quadrupled in area units, and a pressure air chamber forming cover (not shown) that covers the entire lower surface of the playfield plate 5 is provided. A discharge port of an air compressor driven by a motor (not shown) communicates with a pressure air chamber (not shown) sealed with a forming cover, and when the pressure air is press-fitted into the pressure air chamber by the air compressor, Air is ejected upward from the play field plate 5.

  Furthermore, goals 7 are provided at both ends in the longitudinal direction of the upper casing 2, and a protective net 8 is stretched above the central portion in the longitudinal direction of the upper casing 2. A player (not shown) holds the mallet 9. When the pack 10 on the play field board 5 is hit, the pack 10 is lightly floated on the play field board 5 by the air ejected from the air ejection holes 6 of the play field board 5, and lightly moves on the play field board 5 It is possible to run.

  In the form shown in FIG. 1 to FIG. 5, the density of the air ejection holes 6 in the range A at the center of the playfield plate 5 is larger than the density of the air ejection holes 6 in other parts. The floating state of the pack 10 is higher than the floating state of the other portions of the pack 10 due to the supply of a large amount of pressurized air. Thus, the pack 10 hardly decelerates and stops in the range A, and the player hardly hits the pack 10 in the range away from the goal 7, and the player moves from the goal 7. As a result, the air hockey game progresses quickly without interruption, and the interest is remarkably increased.

  Further, if the density of the air ejection holes 6 in the range a having a radius r smaller than the radius R from the center of the play field plate 5 is further increased than the density in the range A having the radius R, the air jetted from the play field plate 5 The distribution of the blown air amount is as shown in FIG. 5, and it may be said that the pack 10 does not stop at the center of the play field plate 5 at all.

  In the form shown in FIGS. 1 to 5, the internal structure of the air hockey game machine 1 is not changed at all, but the internal structure of the conventional air hockey game machine is used, and the arrangement density of the air ejection holes 6 of the play field board 5 is changed. Therefore, the air hockey game machine 1 can be easily obtained at low cost despite having excellent characteristics.

  Next, the best mode of the present invention according to claim 2 shown in FIGS. 6 to 9 will be described.

  As shown in FIG. 6, a goal cover 12 that covers the peripheral wall 11 of the play field board 5 is provided at the position of the goal 7 of the air hockey game machine 1, and the maximum goal width is set below the goal cover 12. A goal width defining member 13 to be defined is integrally joined to the upper surface of the play field plate 5, and a groove 14 oriented in the width direction is formed in the goal width defining member 13, and the goal cover 12 is also directly above the groove 14. A slit 15 is formed at the position.

  Also, a holder 16 is attached to the goal width defining member 13 at a position closer to the center in the width direction than the slit 15 below the goal cover 12, and a goal width reduction block 17 is fitted to the holder 16 so as to be movable up and down. At the same time, the goal width adjusting bracket 20 is slidably fitted into the inclined groove 18 formed in the goal width reducing block 17 and the groove 14 of the goal width defining member 13, and the end of the goal width adjusting bracket 20 is An inclined surface 21 having the same angle as the inclined angle of the inclined groove 18 of the goal width reducing block 17 is formed, and further compressed into the spring receiving recess 22 of the play field plate 5 and the spring receiving recess 23 on the lower surface of the goal width reducing block 17. A coil spring 24 is interposed, and a knob (not shown) is attached to the upper projecting portion 20a of the goal width adjusting bracket 20. The knob is moved to the outside of the air hockey game machine 1 together with the goal width adjusting bracket 20. Then, as shown in FIG. 8, the goal width reducing block 17 is raised by the spring force of the compression coil spring 24, and the pack 10 can pass under the goal width reducing block 17, and the inner edge of the goal width defining member 13 A wide goal width is set by 13a.

  Then, when the knob and goal width adjusting bracket 20 are moved toward the center of the width of the air hockey game machine 1, the goal width reducing block 17 overcomes the spring force of the compression coil spring 24 and descends, as shown in FIG. As described above, the lower surface of the goal width reduction block 17 is in contact with the upper surface of the play field board 5, and the goal field of the play field board 5 is restricted narrowly by the restriction tip 19 of the goal width reduction block 17.

  In the form shown in FIGS. 6 to 9, when the goal width reduction block 17 is raised and the goal width is enlarged, the play field plate is within the range sandwiched between the front end portions 13a of both goal width defining members 13. Since there are no uneven portions or obstacles on the upper surface of 5, there is no possibility that the pack 10 is clogged in the goal 7.

  Further, since the lower end edge of the goal cover 12 is coincident with the upper surface of the goal width defining member 13, the pack 10 thinner than the goal width defining member 13 is lifted upward when passing the lower end edge of the goal cover 12. There is no danger of colliding with goal width reduction block 17.

  Furthermore, since the upper protruding portion 20a of the goal width adjusting bracket 20 protruding upward from the goal cover 12 and the knob attached thereto can be visually observed, the player can know how the goal width is set. Therefore, the player has no doubt that the shot is not successful.

  Further, an embodiment of the invention described in claim 3 shown in FIGS. 10 to 11 will be described.

  Motors 26 are arranged at the four corners of the base 25, and screw rods 27 integrally connected to a rotating shaft (not shown) of the motor 26 are provided upright in the vertical direction. A female screw 28 that can be screwed onto the screw rod 27 is integrally attached to the corner.

  Like the stepping motor, the four motors 26 have their rotational shafts rotated at the same angular speed and at the same angle.

  10 to 11, when the motor 26 is driven to rotate, the screw rods 27 are simultaneously rotated at the same speed, and when the motor 26 is stopped, the screw rods 27 are rotated at the same angle. The upper housing 2 can be moved up and down to the required height while maintaining the horizontal state, so that the height of the upper housing 2 can be adjusted according to the height and posture of the player, and the horizontal state can be reliably maintained. As a result, the player can fully enjoy the hockey game.

  Further, even if a large vertical force is applied to the upper housing 2, the screw rod 27 and the female screw 28 can be relatively firmly held in their mutual positional relationship, so that the upper housing 2 is displaced up or down or tilted. There is nothing at all.

  In the form shown in FIGS. 10 to 11, four screw rods 27 are rotatably supported on the base 25 while standing upright, and a sprocket (not shown) is integrally fitted to the lower end of the screw rod 27. If an endless chain (not shown) is placed on the four sprockets, and the drive sprocket directly connected to the rotating shaft of the motor 26 is engaged with the endless chain, a single inexpensive motor 26 is sufficient, greatly reducing costs. Is possible.

  Furthermore, the best mode of the invention of claim 4 shown in FIGS. 12 to 14 will be described.

  Casters 3 and telescopic legs 4 are provided on base pieces 31 at four corners of a base frame 30 formed by integrally joining shape steels such as angle members vertically and horizontally, and a pivot piece 32 at one end of the base frame 30 is provided. One end of a pair of left and right elongate members 34 parallel to each other is pivotally attached to a support shaft 35 so as to be tilted so that one support leg 33 is formed, and the longitudinal direction of the pair of left and right elongate members 34 on the support leg 33 The other support leg 36 is configured by pivotally attaching the center part in the longitudinal direction of the pair of left and right elongated members 37 parallel to each other on the other support leg 36 to the center part so as to be tiltable about the center axis 38.

  In addition, one end of the left and right elongated horizontal member 40 in the lifting frame 39 is pivotally attached to the upper end of one end of the pair of left and right elongated members 37 in the other support leg 36 to form the lifting frame 39. An upper housing 2 having a play field plate 5 is integrally attached to the upper surface of the lifting frame 39.

  Further, the upper ends of the pair of left and right elongated members 34 in the pivotal support piece 33 are held by the horizontal guide member 41 on the other end side of the elongated member 40 in the elevating frame 39 so as to be movable in the horizontal direction. The lower ends of the pair of left and right elongated members 37 on the support leg 36 are held by a horizontal guide member 42 on the other end side of the base frame 30 so as to be movable in the horizontal direction.

  Furthermore, support rods 43 and 44 oriented in the left-right horizontal direction are integrally stretched over the elongated member 37 of the other support leg 36 over the longitudinal direction of the elongated member 37, and the motor support plate 45 is attached to the support rods 43 and 44. Is mounted integrally on the motor support plate 45, the motor 46 is mounted integrally, the tip of the arm 47 integrally mounted on the rotating shaft (not shown) of the motor 46, and the elongated member of one support leg 33 Both ends of a connecting piece 49 are pivotally attached to a projecting piece 48 attached to 34.

  Note that receiving pieces 50 are integrally attached to the four front, rear, left and right sides of the base frame 30.

  In the form shown in FIGS. 12 to 14, in a state where one support leg 33 and the other support leg 36 are lying down, the lifting frame 39 is locked to the upper horizontal piece of the receiving piece 50, and the upper housing 2 is stable. And kept at the minimum height.

  Then, when the rotating shaft of the motor 46 is rotated to either one, the arm 47 also rotates, and the projecting piece 48 is pushed upward via the connecting piece 49, and as shown in FIG. 39 can rise, and the height of the upper housing 2 increases accordingly.

  Further, the lifting frame 39 can be lifted and lowered while being held horizontally at any height by the one supporting leg 33 and the other supporting leg 36 assembled in a panda graph manner.

  Furthermore, since the arm 47 can be rotated relatively quickly by the motor 46, the elevation adjustment of the upper casing 2 can be completed within a short time.

  The specific structure of the pack 10 used in the air hockey game machine 1 will be described with reference to the best mode of claim 5 shown in FIGS.

  The pack 10 made of thermoplastic resin and injection-molded includes a boss 51 at the center, a plurality of spokes 52 bent in a spiral shape from the outer peripheral surface of the boss 51, and a spoke The spoke part 52 is formed with a smooth curved surface like a wing and is inclined as shown in FIG.

  In the form shown in FIGS. 15 to 16, the pack 10 rotates while floating on the play field board 5 because it has a shape different from that of an ordinary pack and the spoke portion 52 is inclined. Pack 10 draws a unique trajectory while rotating.

  Finally, the best mode of the present invention as claimed in claim 6 shown in FIGS. 17 to 19 will be described.

  The general shape of the pack 54 is a substantially disk shape, and the center portion 55 of the pack 54 is made of polyacetal having high softening temperature and high self-lubricating property, or nylon or hard thermoplastic resin such as ABS. The outer peripheral portion 56 of 54 is made of a soft thermoplastic resin such as urethane or elastomer whose softening temperature is lower than that of the central portion 55, and the outer peripheral portion 56 made of a soft thermoplastic resin is integrated with the central portion 55 made of a hard thermoplastic resin. Are melt-bonded.

  That is, as shown in FIG. 19, the center mold of the lower mold 58 is injected with a hard thermoplastic resin heated to about 250 ° C. with the upper mold 57 and the lower mold 58 having cavities integrally joined to each other. When the pressure is injected into the cavity from the hole 59 and the hard thermoplastic resin is not sufficiently cured, if the soft thermoplastic resin is injected into the cavity from the outer peripheral portion 60 of the lower mold 58, the central portion 55 and The boundary portion with the outer peripheral portion 56 is joined together in a melted state.

  In this pack 54, the central portion 55 occupying most of the pack 54 is rich in self-lubricating properties and is hard, so that it can easily slide on the play field plate 5 with a low frictional force.

  In addition, since the outer peripheral portion 56 made of a soft thermoplastic resin is integrally joined to the outer periphery of the central portion 55, even if the pack 54 collides with the pack 10, the peripheral wall 11, the goal width defining member 13, etc. The impact force is remarkably relieved at the portion 56, and the occurrence of collision noise is sufficiently suppressed.

1 is a perspective view of an air hockey game machine according to a first aspect of the present invention. It is a top view of FIG. It is a front view of FIG. It is a side view of FIG. It is the side view which illustrated the air ejection amount distribution in another form. It is a principal part perspective view of the goal vicinity of the invention of Claim 2. FIG. 7 is a plan view of FIG. 6. FIG. 7 is a longitudinal front view of FIG. 6 showing a state where the goal width reduction block is raised. FIG. 7 is a longitudinal front view of FIG. 6 showing a state where the goal width reduction block is lowered. It is a side view of invention of Claim 3. It is a front view of FIG. It is a perspective view of invention of Claim 4. It is a side view of the state which lowered the raising / lowering frame in FIG. It is a side view of the state which raised the raising / lowering frame in FIG. It is a top view of the pack of invention of Claim 5. In FIG. 15, it is sectional drawing cut | disconnected along XVI-XVI. It is a top view of the pack of invention of Claim 6. It is sectional drawing cut | disconnected along XVIII-XVIII of FIG. It is explanatory sectional drawing which manufactures the pack shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 0 ... Floor surface, 1 ... Air hockey game machine, 2 ... Upper casing, 3 ... Caster, 4 ... Telescopic leg, 5 ... Play field board, 6 ... Air ejection hole, 7 ... Goal, 8 ... Protective net, 9 ... Mallet , 10 ... Pack, 11 ... Perimeter wall, 12 ... Goal cover, 13 ... Goal width defining member, 14 ... Groove, 15 ... Slit, 16 ... Holder, 17 ... Goal width reduction block, 18 ... Inclined groove, 19 ... Restriction tip , 20: Goal width adjusting bracket, 21 ... Inclined surface, 22 ... Spring receiving recess, 23 ... Spring receiving recess, 24 ... Compression spring, 25 ... Base, 26 ... Motor, 27 ... Screw rod, 28 ... Female screw, 30 ... base frame, 31 ... base piece, 32 ... pivot piece, 33 ... one support leg, 34 ... elongate member, 35 ... support shaft, 36 ... other support leg, 37 ... elongate member, 38 ... central axis, 39 ... elevating Frame, 40 ... elongated horizontal member, 41 ... horizontal guide member, 42 ... horizontal guide member, 43 ... support rod, 44 ... support rod, 45 ... motor support plate, 46 ... motor, 47 ... a 48 ... projection piece 49 ... connection piece 50 ... receiving piece 51 ... boss part 52 ... spoke part 53 ... link part 54 ... pack 55 ... center part 56 ... outer part 57 ... upper mold 58 ... Lower mold, 59 ... Central injection hole, 60 ... Outer peripheral injection hole.

Claims (6)

In an air game machine having at least two goals and allowing the pack to easily slide on the play field board by air jetted upward from air blow holes formed in the play field board.
The air game machine according to claim 1, wherein the air ejection holes are densely arranged at a central portion as compared with other portions of the play field plate. In an air game machine having at least two goals and allowing the pack to slide lightly on the playfield board by the air jetted upward from the air jet holes formed in the playfield board.
Left and right side width defining means for defining the maximum goal width fixed to the play field plate;
Goal width reducing means that is located closer to the center of the goal width than the left and right side width defining means, and that can be moved up and down so as to approach the play field plate and narrow the goal width;
A pair of left and right goal width adjustment operation means provided movably in the width direction of the play field plate;
The pair of left and right goal width reducing means are lifted away from the play field board in a separated state of the pair of left and right goal width adjusting operation means, and the left and right pair of goal width adjusting operation means are moved close to the left and right pair of goal width adjusting operation means. An air game machine, comprising: a pair of goal width reducing means which are close to the play field board and interlocking means for reducing the goal width. A plurality of screw rods that stand vertically in the base,
A female screw threadably engaged with each of the screw rods and rotatably provided on an upper housing provided with a play field plate;
An air game machine comprising: an elevating drive means for rotating and driving the plurality of screw rods or the plurality of female screws simultaneously at the same rotational speed. A base frame placed horizontally on the floor or ground;
One supporting leg having one end of a pair of left and right elongated members parallel to each other pivoted to one end of the base frame;
A pair of left and right elongated members of the one supporting leg in the longitudinal center portion of the other pair of left and right pairs of parallel elongated left and right elongated members of the other supporting leg pivotally attached to each other;
An elevating frame provided with a play field plate on the upper end thereof, with one end of the left and right elongate horizontal member of the elevating frame pivotably attached to the upper end of one end of the pair of left and right elongate members on the other support leg;
It comprises an elevating drive means for changing the interval between the two pairs of support legs or between the base frame and the elevating frame so as to be enlarged and reduced,
The upper ends of the pair of left and right elongated members on the one supporting leg are held by the horizontal guide member on the other end of the left and right elongated members on the lifting frame so as to be movable in the horizontal direction, and An air game machine, wherein a lower end of the other end of the pair of left and right members is held by a horizontal guide member on the other end of the base frame so as to be movable in the horizontal direction. In a pack that has at least two goals in an air game machine, and can be slid easily on the play field board by air jetted upward from air blow holes formed in a number of play field boards,
The pack includes a central boss portion, a plurality of spoke portions that diverge in a radial direction from the outer peripheral surface of the boss portion, and a ring that is integrally coupled to an outer end portion of the spoke portion. Part and
The pack, wherein the spoke part is formed in a shape inclined in one direction like a blade of a propeller with respect to a plane perpendicular to the center line of the boss part. In a pack that has at least two goals in an air game machine, and can be slid easily on the play field board by air jetted upward from air blow holes formed in a number of play field boards,
The general shape of the pack is a substantially disk shape,
The central part of the pack is made of a hard thermoplastic resin having a high softening temperature and a high self-lubricating property, and the outer peripheral part of the pack is made of a soft thermoplastic resin having a softening temperature lower than that of the pack central part,
The pack, wherein the outer peripheral portion of the pack made of the soft thermoplastic resin is integrally melt-bonded to the central portion of the pack made of the hard thermoplastic resin.

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