CA1314066C - Method of and apparatus for fusing resin members such as bumper beam and bumper face of automobile bumper - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
An automobile bumper comprises a bumper face and a bumper beam constructed of members molded of thermoplastic resin. The bumper beam includes at least two members of thermoplastic resin having flanges for forming beam flanges together when the members are fused to each other, the beam flanges being fused to an inner surface of the bumper face. An FRP sheet is continuously heated in an atmosphere having a temperature successively lowered from a temperature higher than a resin melting temperature at which a resin of the FRP sheet is melted so that the entire FRP sheet is increased through successive heating stages to a temperature between the resin melting temperature and a resin degradation temperature at which the resin of the FRP
sheet is degraded. Heaters are brought into close proximity with joining surfaces to be fused of at least two parts of synthetic resin with a prescribed spacing therebetween for melting the joining surfaces, and thereafter the melted joining surfaces are pressed against each other to fuse the parts together. At least one of the at least two parts comprises an FRP product made of glass fibers reinforced with a thermoplastic resin, the joining surfaces of the FRP product having a plurality of projections containing the thermoplastic resin only, the projections being melted when the parts are fused together.

Description

!,32 F~

3OF AUTOMOBILE suMpER

BACKGROUND OF THE INVENTION
6 1. Field oE the Invention:
7 The present invention relates to a method of and 8 an apparatus for joining resin parts, and more particularly 9 to a method of and apparatus for fusing resin parts or members such as the bumper beam and bumper face of an 11 automobile bumper.
12 2. Description of the Relevant Art:
13 Automobile bumpers generally comprise an outer 14 bumper face and an inner bumper beam joined to an inner surface of the bumper face for reinforcing the same, the 16 bumper being being adapted to be mounted on an autombile 17 body. The bumper face and beam have heretofore been heavy 18 and liable to produce rust since they are made of pressed 19 steel sheet.
Thermoplastic resin such as polypropylene or ~21 polyethylene is employed to make relatively large products 22 inasmuch as it is lightweight and highly rigid. Where ; 23 ~automobile bumpers are constructed of such thermoplastic 24 resin, they are Iightweight and less apt to develop rust.
For injectian molding a relativley large resin component~
26 it~ i5 general to form smaller~ divided members separately 27 and then join the formed members subsequently into the ,: ~

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1 31 406~

1 resin component so that molds required are not increased in 2 size and molded members can easily be removed from the 3 molds. It is preerable to form an automobile bumper by 4 molding a bumper beam and a bumper face separately.
Various methods are available to join the bumper beam and 6 face to each other. For example, they may be joined by 7 adhesive, or interconnected by mechanical parts such as 8 screws. Since they are made of thermoplastic resin, they 9 may be joined by heating and fusing their joining surfaces with panel heaters held thereagainst and then pressing the 11 fused joining surfaces to each other to connect the members 12 integrally to each other.
13 The bumper beam is required to be higher in 14 rigidity since it supports the bumper face, and hence should be reinforced by another member. There has been 16 developed a plastic composite material known as stampable 17 resin sheet, which can be stamped to a desired shape. One 1~ known such stampable resin sheet is a glass Eiber 19 reinforced resin or plastic (hereinafter referred to as FRP) sheet comprising glass fibers impregnated with 21 thermoplastic resin such as polypropylene or polyethylene.
22 This sheet has a thickness ranging from 2 to 4 mm. It is 23 preferable to form the above divided members by stamping a 24 lamination of such sheets. The resin sheet thus formed is as rigid as steel sheet.
26 Before stamping a lamination of FRP sheets, each 27 of the sheets must be fused by a heater or in a heated .

l atmosphere. However, since the thermal conductivity of the 2 resin is small, iE the sheet were quickly heated, the 3 surface layer thereof would reach a degradation temperature 4 Td before the inside portion oE the sheet would reach a melting temperature, resulting in degradation of the sheet.
6 Therefore, it is current practice to heat an FRP sheet 7 gradually in a relatively low-temperature atmosphere so ~ that the temperature Ti' of the inside area o the sheet 9 reaches a resin melting temperature Tm before the temperature Ts' of the surface layer of the sheet reaches a 11 resin degradation temperature Td, as shown in FIG. 28 of 12 the accompanying drawings. The graph of FIGo 28 has a 13 horizontal axis representing heating time t and a vertical 14 axis representing resin temperature Tp. It takes 4 minutes and 30 seconds to reach a heating completion time tc after 16 a heating starting time tO. Accordingly, the efficiency of 17 the heat treatment of the sheet is low r and so is the 18 production rate for stamping the lamination of FRP sheets.
19 The processes for joining resin members using adhesive of mechcanical parts are complex and have a low 21 production efficiency. The process for joining resin 22 members through fusion is more preferable.
23 ~ven where the latter fusion process is employed, 24 however, it is somewhat difficult to have large joining areas of the bumper face and face. Moreover, fused resin 26 may be attached to the panel heaters, and foreign matter ~ 27 such as carbides may be trapped in the fused areas of the ~ :

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1 bumper face and beam, resulting in a reduced degree of 2 bonding strength. One solution to these problems is to 3 coat the surfaces of the panel heaters with Teflon.
4 However, since Teflon layers are li!{ely to peel off, the panel heaters have to be replaced periodically. In case 6 the joining surfaces of the bumper beam and face are of 7 different shapes, different heaters should be used for 8 heating the jointing areas of different shapes. With an 9 increased number of heaters used, the entire fusing apparatus is complex in structure. Furthermore, divided 11 members formed by stamping FRP sheets contain ~ibers even 12 at the joining surEaces, which become short of fusible 13 resin and tend to develop insuEficient joining forces.
14 The present invention has been made in view of the aforesaid problems oE the convetional automobile 16 bumpers, the process of stamping FRP sheets, and the 17 process oE fusing together bumper beam and face as resin 18 parts.

It is an object of the present invention to 21 provide an automobile bumper of thermoplastic resin which 22 is lightweight, highly rigid, and does not require another 23 member for reinforcing a bumper beam.
24 ~nother object of the present invention is to provide a method of heating an FRP sheet highly efficiency 26 so that a subsequent process of stamping a lamination of 27 FRP sheets can be effected with increased production .

efficiency.
2 Still another object o the present invention is 3 to provide a method of fusing thermoplastic resin parts 4 such as bumper beam and face of an autombile bumper while preventing foreign matter from being trapped in fused areas 6 Of the parts and allowing heaters to be used for a long 7 periof of time.
8 To achieve the above objects~ there is provided 9 an automobile bumper comprising an outer bumper face, a bumper beam joined to an inner surface oE the bumper face 11 for reinforcing the bumper face, the bumper beam being 12 adapted to be mounted on an automobile body, the bumper 13 face and the bumper beam comprising parts molded of 14 thermoplastic resin, the bumper beam including at least two members of thermoplastic resin having joining surfaces to 16 be fused to each other, and flanges for forming beam 17 flanges together when the members are fused to each other, 18 the beam flanges being fused to an inner surface of the 19 bumper face.
There is also provided a method of heating an FRP
21 sheet to be stamped, comprising the step of continuously 22 heating the FRP sheet in an atmosphere having a temperature 23 sdccessively lowered from a temperature higher than a resin 24 ~melting temperature at which a resin of the FRP sheet is melted so that the entire FRP sheet is increased through 26 successive heating stages to a temperature between the 27 resin melting temperature and a resin degrada-tion 1 temperature at which the resin of the FRP sheet is 2 degraded.
3 There is also provided a method of fusing at 4 least two parts of thermoplastic resin to each other, comprising the steps of bringing heaters into close 6 proximity with joining surfaces to be fused of the parts 7 with a prescribed spacing therebetween for melting the 8 joining surfaces, and pressing the melted joining surfaces g against each other to fuse the parts together. ~t least one of the at least two parts comprises an FRP product made 11 of glass fibers reinforced with a thermoplastic resin, the 12 joining sur~aces of the FRP product having a plurality of 13 projections containing the thermoplastic resin only, the 14 projections being melted when the parts are fused together.
The above and further objects, details and 16 advantages of the present invention will become apparent 17 from the following detailed description of preferred 18 embodiments thereof, when read in conjunction with the 19 accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS
21 FIG. 1 is a perspective view of a bumper face of 22 thermoplastic resin and a bumper beam of thermoplastic 23 resin according to the present invention, before they are 24 fused together;
FIGS. 2 through 4 are views explaining a heating 26 method for stamping one of two members of the bumper beam, 27 FIG. 2 showing a device for heating an FRP sheet, FIG. 3 ' 1 being a graph of temperatures of the FRP sheet in 2 respective steps of operation of the heating device, FIG. 4 3 schematically show.ing steps of the heating process;
4 FIG. 5 is a graph o temperatures oE an FRP sheet in various steps of a heating method according to another 6 embodiment of the present invention;
7 FIGS. 6 and 7 are enlarged plan and fragmentary 8 cross-sectional views of a fused surface of the FRP bumper 9 beam;
FIGS. 8 through 13 are elevational views of an 11 apparatus according to the present invention for fusing the 12 bumper face and beam shown in FI~. 1, the views showing 13 successive steps of operation of the apparatus;
14 FIG. 14 is a cross sectional view of a heater in the fusing apparatus;
16 FIG. 15 is a cross-sectional view of an 17 automobile bumper according to another embodiment of the 18 present invention;
19 FIG. 16 is an exploded cross-sectional view of a bumber beam of the bumper shown in FIG. 15;
21 FIGS. 17 through 21 are elevational views of an 22 apparatus according to the present invention for fusing 23 together members of the bumper beam of FIG. 16, FIG. 17 24 being a front elevational view, partly in cross section, of ; ; 25 the fusing apparatusl FIGS. 18 through 21 being side 26 elevational views of the fusing apparatus showing the 27 successive steps of operation thereof;

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1 FIG. 22 is a front elevational view of the fusing 2 apparatus;
3 FIG. 23 is a side elevational view of the fusing 4 apparatus;
FIG~ 24 is a plan view of the fusing apparatus;
6 FIGS. 25A through 25D are views showing a process 7 vf clamping the bumper face;
8 FIGS. 26 and 27 are views sho~ing respective 9 steps of melting and fusing the joining surfaces of the bumper face and beam; and 11 FIG. 28 is a graph showing temperatures of an FRP
12 sheet in various steps of a conventional heating method.

14 Bumper beam and face of a front automobile bumper will hereinafter be described as thermoplastic resin parts 16 or components.
17 As shown in FIG. 1, a front automobile bumper 50 18 comprises an outer bumper face 1 and an inner bumper beam 2 19 joined to an inner surface of the bumper face 1 to reinforce the same. The bumper beam 2 is thermally fused 21 to the inner surEace of the bumper face 1 by a method ~22 described later on. The bumper face 1 is formed by 23 ~ injecting molding thermoplastic resin such as polyethylene 24 or polypropylene, for example. The bumper beam 2 is formed by stamping glass fiber reinforced resin or plastic (FRP).
26 The bumper face 1 has a grille 3 in its front lower portion 27 and opposite side ends 4 directed backwards at a 1 substantically right angle. The bumper beam 2 comprises 2 two members or parts 5, 6. The member 5 has a cross-3 sectional shape including upper and lower shallow channels and a single, relatively deep central channel. The member 6 haa a cross-sectional shape having a wide central 6 channel. Flat front surfaces 5a, 5b of the upper and lowe 7 channels and a flat front surface 5c of the central channel 8 of the member 5 are thermally fused to corresponding flat 9 rear surfaces 6a, 6b, 6c of the member 6 by a method described later. The bumper beam 2 is constructed of the 11 members 5, 6 thus thermally fused together. With the 12 members 5, 6 fused together, upper and lower flanges 5d, 5e 13 of the member 5 lie flush with upper and lower flanges 6d, 14 6e, respectively, of the member 6, jointly forming upper and lower flat flanges 2a, 2b of the bumper beam 2. The 16 flanges 2a, 2b are thermally fuxed to a rear surface la of 17 the bumper face 1, thus completing the bumper 50.
~18 The member 5 of the bu~per beam 2 is formed in 19 the following manner (since the member 6 is also formed in the same manner, it will not be described in detail):
Zl FIG. 2 schematically shows a heating device in ~22 which a plurality of FRP sheets 5i are placed on a feeder 23 comprising wire ropes 8 kept taut in a heating furnace 7 ; 24 ~FIG. 4). Each of the FRP sheets 5i has a prescribed width and a prescribed length. The FRP sheet 5i comprises glass ; 26 fibers impregnated with thermoplastic resin such as 7 polypropylene or polyethylene, for example, and has a g :
'~: ' ' ' - ' '' l thickenss ranging from 2 to 4 mm. Heaters 7a, 7b for 2 producing ~ar infrared rays are disposed in the heating 3 furnace 7 above and below the resin sheets 5i in spaced 4 relation thereto for heating the sheets 5i hetween the heaters 7a, 7b. When the sheets 5i are heated, the surface 6 layers and inner ~reas thereof are substantially uniformly 7 melted. ThereaEter, the sheets 5i are stacked into a 8 lamination, placed in dies, and stamped into the beam 9 member 5.
The resin sheets 5i are heated in a plurality of 11 regions, i.e., three zones or stages Zl, Z2, Z3.
12 FIG. 3 shows the relationship between heating 13 time t and resin temperature Tp, the heating time being 14 divided into three zones Zl, Z2, Z3. FIG. 5 schematically shows such a three-step heating process. Denoted at Td in 16 FIG. 3 is a resin degradation temperature and Tm a resin 17 melting temperature.
18 The resin sheets 5i are fed stepwise by the l9 feeder mechanism 8 from a standby position Z0 into the heating furnace 7 in which the sheets 5i are placed in the 21 quick heating zone Zl.
22 In the first zone Zl, the resin sheets 5i are 23 quickly heated for about 40 seconds in an atmosphere at a 24 temperature of about 400C. As a result, the surface layer temperature Ts of the resin sheets 5i is rapidly inreased 26 as shown in FIG. 3 at a rate higher than the conventional 27 rate. The temperature Ti of the inner area of the resin . ~ . .

1 sheets 5i is also quickly increased at a rate lower than 2 that of the surface layer temperature Ts. The heating in 3 the intensive heaing zone Zl is finished beEore the 4 temperatures Ts, Ti reach the resin melting temperature Tm.
The sheets 5i are then fed stepwise into the 6 second medium heating zo~e Z2, in which they are heated in 7 an atmosphere at about 300C or more specifically at 320C
8 in this ernbodiment continuously for 40 seconds, for 9 example. The surface layer temperature Ts oE the sheet 5i exceeds the melting temperature Tm, but the inside 11 temperature Ti does not reach the melting temperature Tm 12 though it is higher than the conventional inside 13 temperature, as shown in FIG. 3. The heating in the medium 14 heating zone Z2 is finished before the surface layer temperature Ts reaches the degradation temperature Td.
16 Thereafter, the sheets 5i are fed stepwise in-to 17 the third less intensive heating zone Z3, in which they are 18 heated in an atmosphere at about 250C slightly lower than 19 the degradation temperature Td continuously for ~0 seconds, ~or example. The sur~ace layer temperature Ts of the sheet 21 5i keeps above the melting temperature Tm, and the inside 22 temperature Ti exceeds the melting temperature Tm.
23 In the above heating process, the surface layer 24 and inside area of each oE the resin sheets 5i are melted.
The sheets 5i are stacked in a zone Z4 as shown in FIG. 4, 26 and then placed into dies by which they are stamped into 27 the member 5. ~lthough three sheets 5i are shown as being 1 stacked, the number of stacked sheets may be varied 2 dependent on the member into which the sheets are to be 3 stamped. The total heating time is ?. minutes, which is 4 about half the conventional hea-ting time of 4 minutes and 30 seconds as shown in F~G. 28.
6 The resin sheets 5i are continuously heated in 7 atmospheres of temperatures successively lower than a 8 temperature (400C) lower than the resin melting 9 temperature Tm (about 180C). Thus, the heating time is much shorter than the heating time of the conventional 11 method as shown in FIG. 28 by which a sheet is hetaed in a 12 single atmosphere at a relatively low temperature. The 13 efficiency of the heating process is increased, and so is 14 the production efficiency of the process of stamping the stacked sheets.
16 While the sheets 5i are heated separately in the 17 three zones Zl, Z2, Z3, they may be heated in two zones.
18 FIG. 5 shows the relationship between the sheet heating 19 time t and the sheet temperature Tp according to such a ~modification. In this modification, the sheets 5i are 21 heated Eor about 50 seconds in an atmosphere at about 400C
22 in an intensi~e heating zone 21'. Then, the sheets 5i are 23 heated Eor about 70 seconds in an atmophere at about 250C
24 in a less intensive zone Z3'. The surface layers and inner areas of the sheets 5i are substantially uniformly heated .
26 in the total time of 2 minutes. The same advantages as 27 those of the heating process using the three zones Zl - Z3 : . . . ' -1 are offered by the modified heating process.
2 When the members 5, 6 are stamped, their surfaces 3 5a, 5c, 5b and 6a, 6c, 6b to be Eused are provLded with a 4 number of projections, and the flat surfaces 5d, 5e and 6d, 6e oE the members 5, 6 which jointly form the surfaces 2a, 6 2b of the bumper beam 2 to be fused to bumper face 1 are 7 also provided with a number of projections, in the manner 8 described below. FIGS. 6 and 7 show, by way of example, 9 the fusing surface 5a of the member 5 of the bumper beam 2, which has a number of projections formed thereon. As shown 11 in FI. 7, the member 5 is formed by impregnating glass 12 fibers F with resin P.
13 A number of projections 5j are formed on the 14 fusing surface 5a of the member 5. The projections 5j do not contain fibers F but contain only resin P. As 16 illustrated in FIG. 6, the projections 5j are formed in a 17 mosaic pattern with grooves 5k defined therebetween. As 18 shown in FIG. 7, each of the projections 5j has a width wl 19 shorter then the fibers F, the width wl being in the range of from 3 to 10 mm. Each of the grooves 5k has a width sl 21 smaller than the thickness of the fibers F, the width sl 22 ranging from 0.5 to 1.0 mm. Thus, the fibers F are 23 prevented from entering or being exposed in the grooves 5k.
24 The height hl of the projectlons 5j, and hence the depth of the grooves 5k are in the range of 0.5 to 1.0 mm so that a 26 sufficient fused layer is formed when the sheet is fused.
27 A method of thermally fusing the bumper beam 2 1 and the bumper face 1 as clivided components oE thermo-2 plastic resin, and an apparatus for carrying out such a 3 method will be described with reference to FIGS. 8 through 4 13.
As shown in FIG. 8, a fusing apparatus generally 6 designated by the reference numeral 10 has a base 11 on 7 which laterally spaced rai~s 12, 13 are mounted. The rails 8 12 support thereon a first movable carriage 14 on which the 9 beam members 5, 6, not yet joined, are placed, the first movable carriage 14 being movable on the rails 12. The 11 rails 13 support thereon a second movable carriage 15 on 12 which the bumper face 1 is placed, the second movable 13 carriage 15 being movable on the rails 13. The second 14 movable carriage 15 has a plurality of laterally swingable arms 16 having respective vacuum pads 17 disposed on the 16 inner sides of their upper ends for fixing the bumper ace 17 1 under suction. The second movable carriage lS moves on 18 the rails 13 with the bumper face 1 fixedly positioned by 19 the vacuum pads 17.
On the base 11, there are vertically disposed a 21 plurality of posts 18 positioned out of interference with 22 the path of movement of the first movable carriage 14 23 supporting the beam 2 thereon and also out of intererence 24 with rails 29, described later. A support plate 19 is Z5 attached to the upper ends of the posts 18 and supports 26 thereon a first cylinder unit 20 and a second cylinder unit 27 21. The first and second cylinder units 20, 21 serve as 1 first and second lifting devices, respectively. The Eirst 2 cyl.inder unit 20 has a rod ~Oa con~ractably extending 3 downwardly and supporting a first clamp 22 on its lower 4 end. The second cylinder unit 21 has a rod 21a contra~tably extending downwardly and supporting a second 6 clamp 23 on its lower end. ~ plurality of arms 24 7 supporting a heater 25 between their lower ends depend from 8 the support plate 19, the heater 25 extending in a 9 direction normal to the sheet of FIG. 8. The arms 2~ and the heater 25 are positioned out of interference with the 11 path of vertical movement of the second clamp 23 caused by 12 the second cylinder unit 21.
13 As shown in FIG. 14, the heater 25 comprises a 14 tube 26 of quartz having substantially the same longitudinal dimension as those of the beam members 5, 6, 16 and a coiled electric heater wire 27 inserted in the tube 17 26. The tube 26 can be coupled to another tube and can 18 flexibly be bent. The tube 26 may be made of metal. The 19 heater wire 27 is preferably a Nichrome wire~
A plurality of post5 28 are vertically disposed 21 on the base 11 outside of the rails 12, 13, the posts 28 22 being shorter than the posts 18. Laterally extending rails 23 29 are mounted on the upper ends of the posts 28, and ~4 mobile bodies 30 are movably mounted respectively on the rails 29. One of the mobile bodies 30 supports thereon a 26 third cylinder unit 31 having a rod 31a contractably 27 extending downwardly with an arm 32 attached to -the lower 1 end thereof. The rail 29, the mobile body 30, the cylinder 2 unit 31, and the arm 32 constitute one assembly, and 3 another identical assembly is positioned behind the 4 illustrated assembly. Four heaters 33, which are identical in str~cture to the heater 25, extend between the arms 32 6 in a direction normal to the sheet of FIG. 3. A vertically 7 swingable pallet 34 is attached between the mobile bodies 8 30 for supporting the bumper beam 2. The pallet 34 extends 9 between the rails 29 and has a longitudinal dimension larger than that of the bumper beam 2. The heaters 33 have 11 a longitudinal dimension that is substantially the same as 12 that of the bumper face 1.
13 The process of thermally fusing the bumper beam 2 14 and the bumper face 1 together using the fusing apparatus 10 will be described below. The first movable base 14 and 16 the second movable base 15 are driven at a prescribed 17 sequence by a driver mechanism (not shown), and the 18 cylinder units 20, 21, 31 are controlled at a prescribed 19 sequence by a control mechanism (not shown). For the sake of brevity, these driver and control mechanisms will not be 21 described in detail as they have no direct bearing on the 22 present invention. The first clamp 22, the second clamp 23 23, and the arm 32 are vertically moved by extension and 24 contraction of:the first, second, and third cylinder units 20, 21, 31, respectively~ Therefore, operation of the 26 cylinder units 20, 21, 31 will not be described.
27 (A) First, the members 5, 6 which are not yet , : . ! -1 joined are set on the first movable base 14 in a stac~ed 2 condition, as shown in FIG. 8. Then, the Eirst movable 3 base 14 is moved to the right (FIG. 8) and then stopped 4 directly below the first clamp 22.
(s) ThereaEter, the rod 20a of the Eirst cylinder 6 unit 20 is extended to lower the Eirst clamp 22 to the 7 position of FIG. 9. The clamp 22 engages in the three 8 channels of the member 5 of the bumper beam 2 to grip the g member 5. The rod 20a is then contrcted to lift the Eirst clamp 22 and hence the member 5 therewith.

11 tC) The mobile bodies 30 are moved to the left 12 and stopped in a position between the members 5, 6, as 13 shown in FIG. 10. Before the mobile bodies 30 are moved, 14 the rod 31a has been contracted to lift the arm 32 and the pallets 34 ha~e been swung upwardly.
16 (D) Then, the first cylinder unit 20 and the 17 third cylinder units 31 are extended to lower the member 5 18 and the arm 32 to the position oE FIG. 11. The heaters 33 19 are now positioned between the flat surfaces 5a, 5b, 5c of the member 5 and the flat surfaces 6a, 6b, 6c of the member 21 6. The heaters 33 and the flat surfaces 5a, 5b, 5c and 6a, 22 6b, 6c are preferably spaced a distance ranging from 5 to 23 15 mm, and the heaters 33 are preferably heated to a 24 temperature ranging from 500 to 600C. The flat surfaces Sa, 5b, 5c, 6a, 6b, 6c are melted by infrared rays emitted 26 from the heaters 33. Since the flat surfaces have ~ 27 projections, as described above, they are well melted at an :

1 increased rate.
2 (E) Subsequently, the first clamp 22 and the arm 3 32 are elevated, and then the mobile bodies 30 are moved to 4 the right to displace the arm 32 out o~ the space between the members 5, 6. Immediately thereafter, the member 5 6 with the lower flat surfaces 5a, 5bl 5c melted is lowered 7 into contact with the melted upper surfaces 6a, 6b, 6c of 8 the member 6l as shown in FIG. 12. The member 5 is pressed 9 against the member 6 by -the first cylinder unit 20. The members 5, 6 are integrally fused to each other into a 11 bumper beam 2. The pallets 34 are closed right after the 12 mobile bodies 30 are moved rightwardly.
13 (F) In the position of FIG. 12, the completed 14 beam 2 is still gripped by the first clamp 22. The first clamp 22 and the bumper beam 2 gripped thereby are lifted 16 above the mobile bodies 30, which are then moved to a 17 position directly below the first clamp 22, i.e., the 18 bumper beam 2. Then, the bumper beam 2 is lowered onto the 19 pallets 34 of the mobile bodies 30. The bumper beam 2 is released from the first clamp 22 and placed on the pallets 21 39. Thereafter, the first clamp 22 is elavated, as shown 22 in FIG. 13.
23 (G) The mobile bodies 30 is moved to a position 24 directl~ below the second clamp 23, which is then caused to descend to grip the bumper beam 2, as illustrated in FIG.
26 8. Prior to this, the bumper face 1 has been set on the 27 second movable base 15. The second clamp 22 is lifted 1 until the flat flanges 2a, 2b of the bumper beam 2 are 2 positioned near the heaters 25 on the lower end of the arms 3 24. The Elat flanges 2a, 2b and the heaters 25 are spaced 4 5 to 15 mm from each other. Simultaneously, the second movable base 15 is moved ~o the left until the bumper Eace 6 1 i3 positioned directly beneath the arm 32. The arm 32 is 7 lowered to bring the heaters 33 into confronting relation 8 to the inner surface la of the bumper face 1. At this 9 time, the arms 16 are spread laterally to keep the heaters 33 and the inner surface la of the bumper face 1 spaced 11 apart 5 to 15 mm from each other, as shown in FIG. 9.
12 (H) In the position of FIG. 9, the heaters 25, 33 13 are energized to melt the flat surfaces 2a, 2b of the 14 bumper beam 2 and the inner surface la of the bumper face 1. During this melting period, the members 5, 6 of a next 16 bumper beam 2 are moved to the position below the first 17 clamp 22 by the first movable base 14, and gripped by the 18 first clamp 22, as described above.
19 (I) After the flat surEaces 2a, 2b and the inner surface la have been meltedr the arm 32 is lifted, and the 21 moblle bodies 30 are moved to the left. Therefore, the 22 pallets 34 and the arm 32 are displaced out of the space 23 between the bumper beam 2 and the bumper face 1 and into 24 the position between the next members 5, 6, as shown in FIG. 10.
26 ~ (J) Then, the second clamp 23 is lowered to 27 position the bumper beam 2 inside of the bumper face 1.

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1 The arms 16 are moved toward each other to bring the inner 2 surface la of the bumper face 1 against the flat surfaces 3 2a, 2b of the bumper beam 2, as illustrated in FIG. 11.
4 The bumper face 1 is pressed against the bumper beam 2, S thus completing a bumper 50.
6 (K) ThereaEter, the second clamp 23 is released 7 out of engagement with the bumper 50 and lifted to the 8 position of FIG. 12.
9 (L) The second movable base 15 is moved to the right as shown in FIG. 13. The bumpber 50 is then 11 dismounted from the second movable base 15, which will 12 tHereaEter be supplied with a next bumper face 1.
13 The above proc~ss steps (G) through (L~ are 14 carried out simultaneously with the process steps (A) through (F).
16 Since the bumper beam 2 and the bumper face 1 are 17 made of thermoplastic resin, the bumper 50 is highly rigid 18 and lightweight. The rigidity o~ the bumper 50 is high 19 because the bumper beam 2 is constructed of the two FRP
members 5, 6 fused integrally together, and also because 21 the central surface 5c and side surfaces 5a, 5b of the 22 member 5 fused respectively to the central surface 6c and 23 side surfaces 6a, 6b of the other member 6 and the flanges 24 2a, 2b of the members 5, 6 are fused to the inner surface la of the bumper face 1~
26 The heaters 33 are spaced 5 to 15 mm from the surfaces 5a, 5b, 5c and 6a, 6b, 6c of the members 5, 6 when ''. ' ' . ~ .

1 they are melted in the step (D). ThereEore, melted resin 2 is not attached to the heaters 33 and no foreign matter is 3 trapped in the melted surfaces of the members 5, 6.
4 Therefore, it is not necessary to coat the surfaces of the heaters 33 with Teflon, and the heaters 33 can be used for 6 a long period of time. As a result, automobile bumpers 50 7 can successively be manufactured with high efficiency.
8 Likewise, the heaters 25, 33 are spaced similarly from the 9 surfaces 2a, 2b, la o~ the bumper beam 2 and the bumper face 1 when they are melted in the step (H), resuling in 11 the same advantages as described above.
12 The joining surfaces 5a, 5b, 5c and 6a, 6b, 6c of 13 the members 5, 6 of the bumper beam 2 are melted commonly 14 by one set of heaters 33. Therefore, -the number of heaters for melting these joining surfaces is reduced. Since these 16 heaters 33 are also used to melt the inner surface la of 17 the bumper face 1, the number of the heaters in the heating 18 apparatus 10 is reduced. ~s a consequence, the number of 19 parts of the heating apparatus 10 is reducedl making the heating apparatus 10 compact.
2L The joining surfaces 5a, 5b, 5c and 6a, 6b, 6c fo 22 the members 5, 6 of the bumper beam 2, the joining surfaces 23 Sd, 6d (i.e., 2a), and the joining surfaces 6e, 6e ti.e., 24 2e) have a plurality of projections containing only resin P, as shown in FIGS. 6 and 7. Therefore, these joining 26 surfaces contain a necessary and sufficient amount of resin 27 when they are fused togethert and can be fused with a : ~
~ ~ - 21 -1 sufEicient bonding strength.
2 In the above embodiment, the front automobile 3 bumper S0 is made of thermoplastic resin. ~owever, the 4 present invention is also applicable to a rear automobile bumper. While the bumper beam 2 and -the bumper face 1 are 6 thermally fused together in the illustrated embodiment, any 7 other parts made of thermoplastic resin can be thermally 8 fused by the method of -the present invention.
9 A method of fusing parts of thermoplastic resin according to another embodiment of the present invention 11 will be described with reference to FIGS. 15 through 21.
12 A bumper beam 152 of an automobile bumper 150 13 made of thermoplastic resin as shown in FIG. 15 will be 14 described by way of example as a thermoplastic resin part or member. The automobile bumper 150 comprises a bumper 16 face 151 and the bumper beam 152, which are elongate 17 members of thermoplastic resin. The bumper face 151 has a 18 body 151d of an inverted channel shape including an upper 19 portion 151a, a front portion 151b, and a lower portion 151c. From the lower portion 151c, there extends a skirt 21 151e inclined rearwardly and downwardly and having air 22 slits 151f. The bumpber beam 152 comprrises members 153, 23 154 of FRP, as shown in FIG. 6. The members 153, 154 have 24 joining surfaces 153a, 153b and 154a, 154b, respectively, which are fused to each other. The members 153, 154 have 26 flanges 153c, 153d and 154c, 154d, respectively, bent 90 27 from the outer edges of the joining surfaces 153a, 153b and :

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1 31 406~

1 154a, 154b. These flanges 15~3Cr 153d and 154c, 154d serve 2 as fusing surfaces to be fused to the inner surEace of the 3 bumper face 151. Thus, the joining surfaces 153a, 154a and 4 153d, 154d of the members 153, 154, and the bent flanges 153c, 154c and 153d, 154d thereof jointly form joining 6 portions of a T-shaped cross section of the bumper beam 152 7 which are to be joined to the bumper face 151. The bumper 8 beam 152 is of a substan-tially box-shaped cross section for 9 increased rigidity. Where the bumper beam 152 is constructed of a single molded member rather than the two 11 members 153, 154, spaces Ul, ~2, U3 shown in FIG. 9 serving 12 as undercuts.
13 FIGS. 17 through 21 show a method of fusing 14 together the bumper beam members 153, 154 and an apparatus for carring out such a method.
16 As shown in FIG. 17, a fusing apparatus 100 has 17 base 102 on which there are mounted rails 103 extending in 18 a back-and-forth direction normal to the sheet of FIG. 17.
19 The rails 103 are shown as extending laterally in FIGS. 18 through 21. The righthand side of FIGS. 18 through 21 is a 21 front side of the fusing apparatus 100, and the lefthand 22 side is a rear side thereof. A support base 104 supporting 23 a lower jig 106 is movably supported on thQ rails 103. On 24 the support base 104, there are supported the members 153, 154 of the bumper beam 105 with the substantially L-shaped 26 member 153 below the member 1540 The lower member 153 is 27 clamped on the lower jig 106. The jig 106 has vertical ~ members 107, 108 spaced in the direction normal to the 2 sheet of FIG. 17 and having upper edges 107a, 108a engaging 3 the inner sides o~ the flanges 153c, 153d of the lower 4 member 153. Therefore, slight deformation of the lower member 153 which may be introduced upon stamping is 6 corrected by these jig members 107, 108. The vertical 7 members 107, 108 have longitudinal shapes complementary to 8 the normal shape of the lower member 153 and elongated in 9 the lateral direction in FIG. 17. Positioning pins 109 which are laterally spaced from each other are disposed 11 behind the front vertical member 108 of the lower jig 106.
12 The positioning pins 109 serve to position the upper member 13 154 placed on the lower member 153 in the direction normal 14 to the sheet of FIG. 17 for keeping the members 153, 154 relatively positioned while they are being fused to each 16 other.
17 A shift cylinder 110 (FIG. 18) is disposed behind 18 the support base 104 and has a rod llOa coupled to a rear 19 portion of the support base 104. The support base 104 is movable back and forth by the rod llOa in response to 21 operation of the shift cylinder 110.
; 22 As illustrated in FIG. 17, an upper jig support 23 frame 113 in the form of an inverted channel as viewed in 24 front elevation comprises two vertical frame members 111 disposed one on each side of the base 102 and a horizon-tal 26 frame member 112 interconnecting the upper ends of the 27 vertical frame members 11~. An upper jig support base 114 : - 24 -1 is vertically movably supported in the support Erame 113.
2 The support base 114 is ver-ticaly guided by guides 116 3 coupled to its opposite ends and slidably fitted over 4 vertical guide posts 115. The opposite ends of the suport base 114 are coupled to rods 117a of pressure cylinders 117 6 vertically disposed on the lateral sides of the base 102.
7 The center of the support base 114 is coupled to a rod 118a 8 depending from a pressure cylinder 118 vertically mounted g on the center of the horizontal frame member 112 o~ the support frame 113. The upper jig support base 114 supports 11 an upper jig 119 having depending members 120, 121 spaced 12 from each other in the direction normal to the sheet of 13 FIG. 17. The members 120, 121 of the upper jig 119 are 14 vertically longer and shorter, respectively, so that their lower ends 120a, lOla will engage the inner sides of the 16 flanges 154c, 154d of the upper member 154. The members 17 120 which are complenmentary in shape to the normal shape 18 of the upper member 154 e~tend laterally in FIG. 17.
19 Denoted at 122 in FIG. 18 are hooks mounted on the vertical frame members 111 and engageable with the support base 114 21 for preventing the upper jig 119 from falling when the 22 upper jig 119 is lifted and stored. Denoted at 123 in FIG.
23 17 is an auxiliary clamp jig for additionally clamping the 24 upper beam member 154, and 133 an auxiliary clamp jig for additionally clamping the lower beam member 153.
26 Rails 124 extending in the direction normal to 27 the sheet of FIG. 17 are positioned one on each side of the 1 31 ~066 1 lower support jig base 104 on the base 102. Slide guides 2 126 on the lower ends of laterally spaced support frames 3 125 for a heater 130 (described later) are movable mounted 4 on the rails 124, respectively. The support frame 125 i5 S coupled to a rod 127a of a heater shifting cylinder 127 6 mounted on the base 102~ so that the support frame 125 is 7 bodily movable back and forth. ~ cylinder 128 (FIG. 18) 8 for vertically moving the heater 130 is vertically mounted 9 on the support frame 125 and has a rod 128a to which a heat support base 129 is coupled. The heater 130 is supported 11 on the heater support base 129. As shown in FIG. 17, the 12 heater 130 extends laterally beyond the length of the upper 13 and lower beam members 153, 154 and includes four front and 14 rear, upper and lower heater elements 130a, 130b, 130c, 130d extending along the front and rear joining surfaces 16 153a, 153b, 154a, 154b of the members 153, 154. Designated 17 at 131 in FIG. 17 is a sensor for detecting the temperature 18 of the heater elements 130a - 103d, and 132 a guide mounted 19 on the support frame 125 for vertically moving the heater 130.
21 A process of fusing -the beam members 153, 154 to 22 each other using the fusing apparatus 100 will be described 23 below. The lower jig support base 104, the upper jig 24 support base 114, and the heater support base 125 are driven at a prescribed sequence by the cylinders 110, 118, 26 1~7, 128 controlled by a control mechanism (not shown).
Since the control mechanism is not closely related to the .

.

1 present invention, it will not be described below. In 2 addition, operation of the cylinders 110, 118, 127, 128 3 will not be described below unless required.
4 ~ irst, the members 153, 154 are set on the lower jig 106 as shown in FIG. 18. At thie time, the upper 6 jig 119 is in an elevated position~ More specifically, the 7 support base 104 is moved forwardly along the rails 103 to 8 the rightmost set position. The worker then goes in front 9 of the lower jig 106, iOe., rightwardly of the lower jig 106, to set the lower memberf 153 on the lower jig 106.
11 Thereafter, the upper member 154 is placed on the lower 12 member 153 so that the joining surfaces 153a, 153b, 154a, 13 154b Eace each other. The upper member 154 is positionally 14 limited by the pin 109.
(ii~ Then, the support base 104 is retracted on 16 the rails 103 and stopped in the working position shown in 17 FIG. 19. The rods 117a of the cylinders 117 are 18 contracted, and the rod 118a of the cylinder 118 is 19 extended to lower the upper jig support base 114 and hence the upper jig 119. Upon downward movement of the support 21 base 114 to its lower limit, the members 153, 154 are 22 gripped between the jigs 106j 119 and automatically clamped Z3 forcibly thereby. The lower ends 120a, 121a of the members 24 120, 121 of the upper jig 119 are brought into forced ~25 engagement with the inner sides oE the flanges 154c~ 154d 26 of the upper member 154 placed on the lower member 153, as 27 shown in FIG. 19. Even iE the upper member 154 has 1 slightly been deformed, it is forcibly corrected into its 2 normal shape by the members 120, 121 of the jig 119. The 3 member 154 is firmly held in position by the upper jig 119.
4 The intermediate portion oE the upper member 154 is held by the auxiliary clamping jig 123. The lower member 153 is 6 depressed by downward forces from the upper member 154, so 7 that the upper ends 107a, 108a of the members 107, 108 of 8 the lower jig 106 forcibly engage the inner surfaces of the 9 flanges 153c, 153d of the lower member 153. ThereEore, any slight deformation of the lower member 153 is forcibly 11 corrected by the configuration of the members 107, 108 of 12 the lower jig 106.
13 (iii) ThereaEter, the upper jig 119 holding the 14 upper member 154 is lifted to move the upper and lower members 154, 153 relatively away from each other in the 16 vertical direction. The heater 130 which has been in a 17 standby position is postioned between the upper and lower 18 members 154, 153 in response to Eorward movement of the rod 19 127a of the cylinder 127. The lower member 153 has a step which cooperates with the bumper face 151 in deEining a 21 space for receiving head lights and other members. The 22 heater 130 is lifted so that the lower heater elements 23 130a, 130b will not interfere with the step of the member 4 153. Thereafter, the heater 130 is moved forwardly by the cylinder 127 and then lowered into close priximity with the 26 joining surfaces 153a, 153b of the lower member 153 with a 27 spacing, which may range from 5 to 15 mm, left : :
- , , - , .

1 therebetween. Concurrent with this, the upper member 154 2 is elevated and then lowered to bring the joining surfaces 3 154a, 154b into confronting relation to the upper heater 4 elements 130c, 130d of the heater 130 with a gap ranging from 5 to 15 mm therebetween. The heater 130 and the 6 members 153, 154 are now positioned as shown in FIG. 20.
7 In the position of FIG. 20, the heater elements 130a - 130d 8 of the heater 130 are energized to heat and melt the g joining surfaces 154a, 154b, 153a~ 153b oE the members 154, 153.
11 (iv) After the joining surfaces 154a, 154b, 153a, 12 153b of the members 154, 153 have been melted, the upper 13 member 154 is elevated. The heater 130 is lifted and then 14 retracted out of the position between the members 154, 153 which have been spaced vertically away from each other.
16 Thereafter, the upper jig 119 is lowered to place the upper 17 member 154 onto the lower member 153, so that the melted 18 joining surfaces 154a, 154b/ 153a, 153b are held against 19 each other, as shown in FIG. 21. The cylinders 117, 118 are operated to press the upper and lower members 154, 153 21 to fuse the joining surfaces 153a, 153b, 154a, 154b under 22 pressure. Unwanted deformation of the members 153, 154 is 23 further forcibly corrrected by such pressurized fusing 24 process.
(v) After the upper and lower members 154, 153 26 have been fused together into a bumper beam 152, the upper 27 jig 119 is lifted, leaving the bumper beam 152 on the lower _ ~9 _ 1 jig 106. Then, the lower jig 106 holding the bumper beam 152 thereon is moved forwardly, and the bumper beam 152 is 3 removed.
4 Jn the above processing steps (i) through (v), the beam members 1S3, 154 of thermoplastic resin are fused 6 together while they are being clamped by the upper and 7 lower jigs 119, 106 which are complementary in shape to the 8 normal shape of the members 153, 154. Therefore, slight 9 doformation of the members 153, 154 are forcibly corrected by the shape of the jigs 119, 106. ~s a result, a product 11 o~ a normal shape can be produced. Since the fusing 12 process (i) through (v) can fully be automated, the fusing 13 operation can be performed reliably within a short period 14 of time, with the consequences that the required labor can be saved, the rate of production can be increased, the 16 product quality can be improved and uniformized, and the 17 cost can be lowered. By replacing the upper and lower jigs 18 119, 106 and the heater 130 with other jigs and heater, the 19 fusing apparatus 100 can fuse resin members of other shapes and hence is versatile.
21 In the above embodiment, the members 154, 153 are 22 fused while they are vertically placed one on the other.
23 However, the members to be fused together may be positioned 24 so as to be movable toward and away from each other laterally or back and forth, and the heater may be disposed 26 between these members for heating and melting them.
27 A method of fusing the bumper beam 152 thus .
. ~ . .

1 constructed to the bumper face 151 and an apparatus for 2 carrying out such a method will be described below with 3 referenc~ to FIGS. 22 through 27.
4 As shown in FIG. 22, a fusing apparatus 200 has a base Z03 supporting thereon a frame 202 comprising 6 laterally spaced vertical frame members 202a, and a 7 horizontal frame member 202b interconnecting the upper ends 8 of the vertical frame members 202a.
9 The lefthand side of FIG. 23 is the front of the fusing apparatus 200 where the worker operates the 11 apparatus. The frame 202 is vertically disposed on an 12 intermediate portion of the base 202 in a direction normal 13 to the sheet of Fig. 22. A bumper face fixing jig base 204 14 is mounted on a front portion of the base 203 below the frame 202. The jig base 204 is movably mounted on rails 16 205 mounted on the base 203 and extending in the direction 17 normal to the sheet of FIG. 22. Support members 207, 20 13 are vertically mounted on an upper member 20~ on the jig 19 base 104 and spaced apart from each other in the directionn normal to the sheet of FIG. 22. The front support member 21 207 supports a pressure cylinder 209 having a rod 209a to 22 which there are coupled a member 210 for receiving the 23 upper portion l51a of the bumper face 151 and a lifter 24 cylinder 212 that supports a clamp cylinder 211 having a rod 211a with a clamp finger 213 on its distal end.
26 Between the support members 207, 20~, there is disposed a 27 jig 214 for holding the body 151d of the bumper face 151.

1 31 ~066 1 A pressure cylinder (not shown) supported on the rear 2 support member 208 has a rod 215 projecting forwardly. The 3 rod 215 supports on its distal end a vertically movable 4 clamp finger 216 insertable in the air slits 151f of the skirt 151e oE the bumper face 151.
6 The bumper face 151 can be se~ in place as shown 7 in FIGS. 25A through 25D. ~s shown in FIG. 25A, the bumper 8 face 151 is disposed on the jig 214 with the body 151d 9 positioned downwardly. The upper end of the upper portion 151a is put on the tip end of the receiving member 210.
11 Then, as shown in FIG. 25B, the clamp cylinder 211 is 12 driven to extend the rod 211a to move the clamp finger 213 13 Eorwardly. The lifter cylinder 212 is driven to move the 14 clamp cylinder 211 and the clamp flnger 213 downwardly to the position of FIG. 25C. Then, the clamp cylinder 211 is 16 actuated to retract the clamp finger 213 to clamp the upper 17 end of the upper portion 151a against the tip end of the 18 receiving member 210 as illustrated in FIG. 25D. Although 19 not shown in FIGS. 25A through 25D, the clamp finger 216 (FIG. 23) is lifted when setting the bumper face 151 on the 21 jig 214 to engage in the air slits 151f of the skirt 151e.
22 As a result, the bumper face 151 is reliably set on the jig 23 214.
24 A support frame 217 is disposed behind and below the frame 202, and a cross member 217b extends horizontally 26 between rear vertical frame members 217a of the support 27 frame 217. On the cross member 217b, there is vertically :

.
, ~

1 supported a cylinder 218 by a bracket 219 for vertically 2 moving a heater 222 for heating the bumper face 151. The 3 cylinder 218 has a vertical rod 218a to which a support 4 base 220 is attached. A cylinder 221 for moving a bumper face heater 222 back and forth is mounted on the support 6 base 220, the cylinder 221 having an axis extending in the 7 direction normal to the sheet of FIG. 22. The cylinder 221 8 has a rod 221a with its distal end supporting a holder 222a 9 of the heater 222. As shown in FIG. 22, the heater 222 has a length which is substantially the same as that of the 11 bumper face 151 se-t below the heater 22~, and is shaped so 12 that it is loosely fitted in the space between thè upper 13 and lower portions 151a, 151c of the bumper face 151. The 14 heater 222 comprises two heater elements 222b spaced in the direction normal to the sheet of FIG. 22. In FIG. 23, the 16 heater 222 is in an elevated position between the vertical 17 frame members 202a of the frame 202.
18 ~ cylinder 223 for moving a feed base for the 19 bumper beam 152 back and forth is mounted on a front portion 217c of the rear support frame 217, the cylinder 21 223 having an axis extending in the direction normal to the 22 sheet of FIG. 22. The cylinder 223 has a rod 223a coupled 23 to a slider 226 slidable back and forth on rails 225 on the 24 front support Erame portion 217c. From the slider 226, there extend forward}y two laterally spaced arms 227 having 26 front ends between which a laterally extending 27 channel-shaped feed base 228 for the bumper beam 152 is ' ~ - 33 -, ' ' '' - ':

1 attached, as shown in FIG. 22. The feed base 228 has a 2 horiæontal member 228a which is o~ substantially the same 3 length as that of the bumper beam 152, and vertical members 4 228b mounted on the opposite ends, respectively, of the horizontal member 228a. The bumper beam 152 is set on the 6 feed base 228 by the worker such that its opposite ends are 7 qupported on the vertical members 228b and its intermediate 8 portion are supported on the horizontal member 228a.
9 A jig 229 (FIG. 22) for fixing the bumper beam 152 is disposed between the vertical frame members 202a of 11 the frame 202 and has laterally spaced holders 229a for 12 holding the bumber beam 152 at its laterally spaced 13 openings (not shown) defined in the upper member. The jig 14 229 has a vertically movable base 230 horizontally supported between upper portions of the vertical frame 16 members 202a. Sprockets 23~ are rotatably mounted on lower 17 inner surfaces of the vertical frame members 202a. A drive 18 shaft 231 i~ rotatably supported on the frame 202 by 19 bearing bases 232, 233 and supports sprockets 235 on its opposite ends. Chains 236 are trained around the 21 respective pairs of sproc~ets 234, 235 and have sides or 22 runs fi~ed to the iig base 230. One end 231a of the drive 23 shaft extends out beyond the bearing base 233, and two 24 sprockets 237 are mounted on the end 231a. A cylinder 238 for vertically moving the jiy 229 is vertically mounted by 26 a bracket 239 on the vertical frame member 202a over which 27 the sprockets 237 are positioned. The cylinder 238 has a ., 1 rod 238a having on its upper end an engagement member 240 2 coupled to chains 241 trained around the sprockets 237.
3 When the cylinder 238 is actuated, the rod 238a is 4 vertically moved to move the chains 241 thus rotating the S sprockets 237 to rotate the drive shaft 231. Rotation of 6 the drive shaft 231 causes the chains 236 trained around 7 the sprockets 235, 234 to rotate to vertically move the jig 8 base 230 to which the chains 236 are affixed. As a result, 9 the jig 229 is also moved vertically. Denoted at 202c in FIG. 22 are stoppers for limiting downward movement of the 11 base 230 by engaging the opposite ends of the jig base 230 12 on the vertical frame members 202a.
13 A heater 242 for heating the bumper beam 152 is 14 disposed below the intermediate portion of the horizontal frame member 202b of the frame 202. The heater 242 has 16 symmetrical heater elements 242a, 242b spaced in the 17 direction normal to the sheet o~ FIG. 22. The heater 18 elements 242a, 242b are positioned so as to be aligned 19 respectively with the joining surfaces 153c, 154c and 153d, 154d of the bumper bea~ 152, and are supported on 21 respective front and rear symmetrical holders 243, 244 22 which are pivotally supported. ~s shown in FIG. 22, the 23 heater elements 242a, 242b are long in the lateral 24 direction of the apparatus and have a shape complementary 25 to the front and rear fusing surfaces 153c, 154c and 153d, 26 154d of the bumper beam 152. The holders 243, 244 are 27 plvotally supported on respective depending arms 243a, 244a ~ ~ .

1 and coupled by links 247 to rods 245a of Eront and rear 2 cylinders 245, 246 spaced from each oth~r. The cylinders 3 245, 246 are suported on the horizontal frame member 202b 4 by means of brackets 248. Upon actuation of the cylinders 245, 246, the holders 243~ 244 are selectively closed and 6 opened to move the heater elements 242a, 242b toward and 7 away from each other, or close and open the heater 242. In 8 FIG. 23, the heater 242 is closed and the heater elements 9 242a, 242b are in a lowered position.
A process of fusing the bumper beam 152 to the 11 bumper face 151 using the fusing apparatus 200 will be 12 described below.
13 (I) First, the bumper face 151 is placed on the 14 jig 214 as shown in FIG. 23. As shown FIGS. 25A through 25D, the bumper face 151 is clamped by the clamp fingers 16 213, 216. The upper member 206 over the jig base 204 is 17 moved to the right in FIG. 23, i.e., in the rearward 18 direction of the apparatus, into a heating and melting 19 position. Then, the cylinder 221 is driven, and the heater 222 for heatlng the bumper face 151 is positioned above the 21 bumper face 151. Thereafter, the cylinder 218 is actuated 22 to lower the heater 222 with the support base 220 and the 23 cylinder 221 until the heater elements 222b are positioned 24 within the body 15Id of the bumper face 151, facing the inner surfaces oE the upper and lower portions 151a, 151c 26 of the bumper face 151. In the same manner as the process 27 described with reference to FIGS. 8 through 13, the heater 1 3 1 ~066 1 elements 222b confronts the inner joining surfaces of the 2 body 151d in spaced relation. The heater elements 222b are 3 energized to heat and melt the inner joining surfaces of 4 the body 151d. At the same time, the cylinder 223 is actuated to retract the feed base 228 with the bumper beam 6 152 placed thereon, and the heater elements 242a of the 7 heater 242 for heating the bumper beam 152 are elevated.
8 The bumper beam 152 is set below the heater elements 242a 9 of the heater 242, as shown in FIG. 26.
(II) Then, the jig 229 is lowered to grip the 11 bumper beam 152, and thereafter lifted to bring the joining 12 surfaces 153c, 154c and 153d, 15~d of the bumper beam 152 13 between the heater elements 242a, 242b. The heater 14 elements 242a, 2~2b are now disposed in facing but spaced relation to the joining surfaces 153c, 154c and 153d, 154d 16 in the same manner as described with reference to FIGS. 8 17 through 13. These joining surfaces are then heated and 18 melted by the heater elements 2~2a, 242b.
19 ~III) Thereafter, the heater 222 i5 lifted and then retracted out of the space above the bumper beam 152.
21 The feed base 228 is simultaneously moved back out of the 22 space below the bumper beam 152. Then, the jig 229 is 23 lo~ered to position the bumper beam 152 within the body 24 l51d of the bumper face 151, as shown in FIG. 27, where the joining surfaces of the bumper beam 152 and the bumper face 26 151 are held against each other. The rod 209a of the 27 cylinder 209 and the rod 219 of the opposite cylinder (not 1 shown) are moved toward each other to press the bumper beam 2 152 and the bumper Eace 151 together so that they are 3 firmly fused to each other into a bumper 150.
4 (IV) Subsequently, the jig 229 is released, and the cylinder 209 and the opposite cylinder are also 6 released, followed by returning movement of the ]ig base 7 204 to its original position. The clamp finger 213 is then 8 released to discharge the bumper 150.
9 According to the apparatus 200, the FRP bumper beam 152 and the bumper face 151 oE thermoplastic synthetic 11 resin are automatically heated and fused to produc~ the 12 resin bumper 150 in the successive process steps (I) 13 through (IV). Therefore, the operation efficiency is 14 increased, the manual labor is saved, the cost is lowered, and bumpers can be mass-produced. The fusing apparatus 200 1~ can produce bumpers of various different shapes by 17 replacing the jigs 229, ~14 and the heaters 242, 222 with 18 other jigs and heaters.
19 Although there have been described what are at present considered to be the preferred embodiments of the 2l present invention, it will be understood that the inven-tion 22 may be embodied in other specific forms without departing 23 from the spirit or essential characteristics thereof. The 24 present embodiments are therefore to be considered in all aspects as illustrative, and not restrictive. The scope of 26 the invention is indicated by the appended claims rather 27 than by the foregoing description.

Claims (19)

1. An automobile bumper comprising:
an outer bumper face;
a bumper beam joined to an inner surface of the bumper face for reinforcing the bumper face, the bumper beam being adapted to be mounted on an automobile body;
said bumper face and said bumper beam comprising parts molded of thermoplastic resin;
said bumper beam including at least two members of thermoplastic resin having joining surfaces to be fused to each other, and flanges for forming beam flanges together when said members are fused to each other; and said beam flanges being fused to an inner surface of said bumper face.

2. An automobile bumper according to claim 1, wherein said members of said bumper beam are made of polypropylene impregnated in glass fibers, and said bumper face is made of polypropylene.

3. A method of fusing at least two parts of thermoplastic resin to each other, comprising the steps of:
bringing heaters into close proximity with joining surfaces to be fused of said parts with a prescribed spacing therebetween for melting said joining surfaces; and pressing the melted joining surfaces against each other to fuse said parts together, and wherein said at least one of said at least two parts comprises an FRP product made of glass fibers reinforced with a thermoplastic resin, said joining surfaces of said FRP product having a plurality of projections containing said thermoplastic resin only, said projections being melted when the parts are fused together.

4. A method according to claim 3, wherein said spacing ranges from 5 to 15 mm.

5. A method according to claim 3, wherein said at least two parts are made of polypropylene, said heaters being heated to a temperature ranging from 500 to 600°C.

6. A method according to claim 3, wherein each of said projections has a width ranging from 3 to 10 mm and a height ranging from 0.5 to 1.0 mm, said projections defining grooves therebetween, each of said grooves having a width ranging from 0.5 to 1.0 mm.

7. A method according to claim 3, wherein said at least two parts comprise two members jointly forming a bumper beam for reinforcing a bumper face of an automobile bumper.

8. A method according to claim 3, wherein said at least two parts comprise a bumper face and a bumper beam adapted to be mounted on an automobile body and reinforcing said bumper face, said bumper face and said bumper beam jointly constituting an automobile bumper.

9. A method according to claim 3, wherein said at least two parts comprise a bumper face and two members constituting a bumper beam for reinforcing the bumper face, said bumper face and said two members jointly forming an automobile bumper.

10. A method according to claim 3, wherein said parts are fused by:
setting said parts on a first clamping jig while said parts are being placed one on the other with said joining surfaces of the parts confronting each other;
sandwiching the set parts between said first clamping jig and a second clamping jig with said second clamping jig so that said parts are clamped respectively by said first and second clamping jigs; and moving said first and second clamping jigs away from each other to separate said parts from each other, moving said heaters between the separated parts, and bringing said heaters into close proximity with said joining surfaces of the parts with said spacing therebetween to melt said joining surfaces.

11. A method according to claim 10, wherein said first and second clamping jigs are shaped complementarily to said parts for thereby clamping the parts on said clamping jigs while correcting the parts to normal shapes thereof.

12. An apparatus for fusing at least two parts of thermoplastic resin to each other, comprising:
first heaters;
a first setting mechanism for bringing said first heaters into close proximity with joining surfaces to be fused of said parts with a prescribed spacing therebetween to melt said joining surfaces; and a first pressing mechanism for directing the melted joining surfaces in mutually confronting relation and pressing said joining surfaces against each other to fuse said parts together, and wherein said at least two parts comprise two members jointly forming a bumper beam for reinforcing a bumper face of an automobile bumper;
said first setting mechanism comprising a first movable base for carrying said two members to a prescribed position, a first clamp for gripping one of said two members placed on said first movable base, first drive means for moving said first clamp to move said one member away from the other member, and a mobile body having said first heaters attached thereto for moving said first heaters into and out of a position between the members separated from each other;
said mobile body being arranged to move said first heaters from between said members after said joining surfaces to be fused have been melted by said first heaters;
said first drive means being arranged to press said first clamp against said first movable base to press the melted joined surfaces against each other to fuse said members to each other; and said first pressing mechanism comprising said first clamp, said first drive means, and said first movable base.

13. An apparatus according to claim 12, wherein said at least two parts further include said bumper face, said apparatus further including:
second heaters;
a second setting mechanism for moving said second heaters into close proximity with the joining surfaces of the fused bumper beam with said spacing therebetween to melt and joining surfaces of the bumper beam;
a second movable base for carrying said bumper face to a prescribed position;
said mobile body being arranged to move said first heaters into close proximity with the joining surface of said bumper face to be joined to said bumper beam, with said spacing therebetween, to melt said joining surface of said bumper face; and a second pressing mechanism for directing said melted joining surfaces of the bumper beam and the bumper face into confronting relation and pressing said bumper beam and said bumper face to fuse them together.

14. An apparatus according to claim 13, wherein said mobile body being arranged to carry said bumper beam fused by said first pressing mechanism to another prescribed position;
said second setting mechanism comprising said mobile body, a second clamp for gripping said bumper beam placed on said mobile body, and second drive means for moving said second clamp in a prescribed direction to bring said joining surfaces of said bumper beam into close proximity with said second heaters with said spacing therebetween for thereby melting said joining surfaces of said bumper beam;
said second drive means being arranged to move said second clamp toward said second movable base to bring the melted joining surfaces of said bumper beam into the melted joining surface of said bumper face with said spacing therebetween; and said second pressing mechanism comprising arms mounted on said second movable base and movable toward and away from each other.

15. An apparatus according to claim 13, wherein each of said second heaters comprises a tube of quartz and a heating wire inserted in said tube, and has a longitudinal dimension which is substantially the same as that of said members.

16. An apparatus according to claim 12, wherein each of said first heaters comprises a tube of quartz and a heating wire inserted in said tube, and has a longitudinal dimension which is substantially the same as that of said members.

17. An apparatus according to claim 12, wherein said first setting mechanism comprises a first jig for setting said parts thereon while said parts are being placed one on the other with said joining surfaces of the parts confronting each other, a second jig for sandwiching the set parts between said first jig and said second jig so that said parts are clamped respectively by said first and second jigs, a first drive mechanism for moving said first and second jigs toward and away from each other, and a second drive mechanism for moving said heaters between the parts separated by said first drive mechanism; and said heaters having a shape complementary to the joining surfaces of said parts.

18. An apparatus according to claim 17, wherein said first and second clamping jigs are shaped complementarily to said parts for thereby clamping the parts on said jigs while correcting the parts to normal shapes thereof.

19. An apparatus according to claim 12, wherein said at least two parts comprise a bumper face of thermoplastic resin and a bumper beam of FRP which jointly form an automobile bumper;
said first heaters comprising second and third heaters for heating the joining surfaces of said bumper beam and bumper face;
said first setting mechanism comprising a first feed mechanism for carrying said bumper beam at a prescribed position and carrying the bumper beam to a position confronting said second heater, and a second feed mechanism for carrying said bumper face at a prescribed position and carrying the bumper face to a position confronting said third heater; and said second feed mechanism having a clamping mechanism for clamping said bumper face.