CA2328857C - Securement of head rest support into automobile seat frame - Google Patents
Securement of head rest support into automobile seat frame Download PDFInfo
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- CA2328857C CA2328857C CA 2328857 CA2328857A CA2328857C CA 2328857 C CA2328857 C CA 2328857C CA 2328857 CA2328857 CA 2328857 CA 2328857 A CA2328857 A CA 2328857A CA 2328857 C CA2328857 C CA 2328857C
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Abstract
The headrest support tubes are secured to the seat frame member not by the usual welding, but by gripping the web of the member between two rings or lock-beads swaged into the metal of the tube.
The first ring is swaged-out by compressing the tube. The tube, with the one ring, is then assembled into a through-hole in the web of the frame member. Then, the second ring is swaged into the metal of the tube, on the other side of the web, and the web lies gripped between the rings.
The seat frame member may be an I-section extrusion, or a round tube with localised squeezed-flat areas, flanked by flanges.
The first ring is swaged-out by compressing the tube. The tube, with the one ring, is then assembled into a through-hole in the web of the frame member. Then, the second ring is swaged into the metal of the tube, on the other side of the web, and the web lies gripped between the rings.
The seat frame member may be an I-section extrusion, or a round tube with localised squeezed-flat areas, flanked by flanges.
Description
1 Title: SECUREMENT OF HEAD REST SUPPORT INTO AUTOMOBILE SEAT FRAME
2
3 a This invention relates to the construction of automobile seats, s and is directed particularly tc> the manner of attachment of a s headrest to the frame of an automobile seat.
a to 11 The headrest on an automobile seat is often made adjustable as to lz height. One common way in which the headrest is mounted on the 13 seat in a way that permits height adjustment is for the headrest 14 to be provided with two downwardly extending pegs, and the pegs is engage sockets secured into the frame of the seat. Detent means is are usually provided which interact between the pegs and the l sockets, whereby the headrest may be set, by the occupant of the la vehicle, at one of a number of pre-set heights.
zo The socket in which the peg is received comprises a metal tube.
zl A plastic liner may be provided in the tube, to act as a bearing zz material for the peg. In the conventional system, the tube is z3 welded to a bracket, and the bracket is welded to a frame piece za of the seat. This manner of attachment, though secure enough zs (because it has to be secure by regulation), unfortunately is zs expensive as to the labour time and the materials needed to make z7 it that secure. Any securement system that involves welding za tends to be labour-intensive and therefore expensive, besides z9 being difficult to inspect and test. A welded system generally 3o has to be over-engineered.
32 Also, welding does not lead to high accuracy. The need for 33 accuracy of placement of the headrest on the seat is not high, 34 although the accuracy of the spacing of the pegs and their 35 sockets cannot be too far out; the conventional welded-on system 3s is just about at the limit for accuracy for welding, Which means 3~ that, when welding is used as the basis of the attachment method, 3a skilled care has to be taken, which in turn does nothing to ease 39 the cost problem.
al The invention is aimed at providing a manner of securing a 1 headrest support tube into a seat frame, in a manner that eases 2 some of the compromises that have had to be resorted to in the 3 conventional systems.
a to 11 The headrest on an automobile seat is often made adjustable as to lz height. One common way in which the headrest is mounted on the 13 seat in a way that permits height adjustment is for the headrest 14 to be provided with two downwardly extending pegs, and the pegs is engage sockets secured into the frame of the seat. Detent means is are usually provided which interact between the pegs and the l sockets, whereby the headrest may be set, by the occupant of the la vehicle, at one of a number of pre-set heights.
zo The socket in which the peg is received comprises a metal tube.
zl A plastic liner may be provided in the tube, to act as a bearing zz material for the peg. In the conventional system, the tube is z3 welded to a bracket, and the bracket is welded to a frame piece za of the seat. This manner of attachment, though secure enough zs (because it has to be secure by regulation), unfortunately is zs expensive as to the labour time and the materials needed to make z7 it that secure. Any securement system that involves welding za tends to be labour-intensive and therefore expensive, besides z9 being difficult to inspect and test. A welded system generally 3o has to be over-engineered.
32 Also, welding does not lead to high accuracy. The need for 33 accuracy of placement of the headrest on the seat is not high, 34 although the accuracy of the spacing of the pegs and their 35 sockets cannot be too far out; the conventional welded-on system 3s is just about at the limit for accuracy for welding, Which means 3~ that, when welding is used as the basis of the attachment method, 3a skilled care has to be taken, which in turn does nothing to ease 39 the cost problem.
al The invention is aimed at providing a manner of securing a 1 headrest support tube into a seat frame, in a manner that eases 2 some of the compromises that have had to be resorted to in the 3 conventional systems.
4 s Typically, the operations carried out in a conventional seat s manufactory include welding, bending of frame pieces, securing components together, and assembly, all of which tend to have a a higher labour content. It is an aim of the headrest support 9 system as described herein, to minimise the labour content of the to task of attaching the support tubes to the seat frame piece.
12 Support tubes for headrests are conventionally attached to the 13 seat frame piece by welding a bracket onto the frame piece, and 14 then welding the tube to the bracket. Sometimes, the tube is is pressed into holes in the welded-on bracket; but welding is is nearly always resorted to, to assure that the tube remains in 1~ position on the bracket. Of course, the tubes can be attached is securely enough, but the conventional costs of ensuring that 19 security are high.
2z GENERAL FEATURES OF THE INVENTION
24 The invention lies in the manner of attaching the headrest-2s support-tube. First, the headrest-support-tube is provided with zs a first ring, in which the metal of the headrest-support-tube is z~ expanded radially outwards. The headrest-support-tube is zs assembled into a hole in the web of the seat-frame-piece, with 29 the first ring abutting against the web.
31 The frame-piece, with the headrest-support-tube resting therein, 32 is placed in the die of a punch and die set, with the first ring 33 in the die. The punch then is brought down over the other end of 34 the headrest-support-tube, and a second ring is formed on the 3s other side of the web. When the punch is withdrawn, the web lies 3s gripped between the two rings. Usually, another headrest-3~ support-tube is inserted into the frame-piece, in a similar 3s manner. Then, the seat-frame p:'tece is assembled into a seat, and 39 finally the pegs of the headrest are inserted into the headrest-4o support-tubes.
i THE PRIOR ART
z 3 As mentioned, headrest-support tubes are attached to the seat-4 frame-piece by welding. Sometimes, designers have specified s intermediate brackets, rather than just welding the tube to the 6 frame piece.
a Techniques for mounting a tube into a through-hole in a piece of 9 sheet metal are commonplace, per se. The broad range of options io available include bulk-head fittings generally. Such fittings 11 have included cases where a first bead is provided on the tube on iz one side of the sheet, then a second bead is swaged into the tube i3 after the tube has been inserted into the through-hole. The 14 technique is commonly known as lock-beading.
is is In cases where bulk-head fittings are being designed, a common m requirement is that the fitting' by air- or liquid-tight. It is is recognised that the lock-beading technique is not suitable for is such cases. It is recognised that lock-beading is highly 2o suitable for cases where mechanical integrity is paramount, zi rather than sealing. It is also recognised that lock-beading is 22 highly suitable for cases where access to the beads is only to be 23 had from an axial direction, such as a case where flat-access to z4 the through-hole is denied because the through-hole is surrounded is by raised flanges.
za DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
3o By way of further explanation of the invention, exemplary 3i embodiments of the invention will now be described with reference 32 to the accompanying drawings, in which:
34 Fig 1 is a diagram of an automobile seat frame, shown partly in 3s cross-section, carrying a headrest which is mounted in a 36 manner in accordance with the invention;
37 Fig 2 is a view of some of the components that support the 3a headrest, shown at a preliminary stage of manufacture;
39 Fig 3 is a view of a punch and die set-up, which is used at a ao stage in the manufacture of one of the headrest supports;
41 Fig 4 is a view corresponding to Fig 3 of another stage during manufacture;
2 Fig 5 is a cross-section of the headrest mounting support, shown at a later stage;
a Figs 6a,6b,6c are cross-sections of a tooling arrangement for s forming a metal tube locally into an I-section beam;
s Figs 7a,7c are views on the line 7-7 of Fig 6a, corresponding to the conditions shown in Figs 6a and 6c respectively;
a Figs 8a,8b are cross-sections of a hole-punching arrangement, for making a through-hole in l:he web of the I-beam produced as to in Fig 6c;
m Fig 9 is a view of a headrest-support-tube, shown prior to final iz forming;
i3 Figs lOa,lOb,lOc are cross-sections of a tooling arrangement for i4 ring-bead-locking the headrest-support-tube of Fig 9 into is the through-hole in the web of the I-beam.
is m The apparatuses shown in the accompanying drawings and described is below are examples which embody the invention. It should be i9 noted that the scope of the invention is defined by the zo accompanying claims, and not necessarily by specific features of 2i exemplary embodiments.
z3 Fig 1 shows an automobile seat 20, having a seat frame piece 23.
2a In this case, the seat frame piece 23 made from a length of 2s extruded I-section aluminum. The seat frame piece is bent 2s generally into an inverted U-shape, as shown, in which the z7 horizontal rail 24 of the U-shape forms the horizontal top rail ze of the seat.
3o The headrest 25 of the seat 20 .is formed with two pegs 26, which 3i protrude downwards, as shown. ~.rhe pegs engage into support tubes 3z 27, which are integral with the frame of the seat. The support 33 tubes 27 are fixed firmly to the horizontal rail 24, and in fact 34 the support tubes pass through holes 28 in the web 29 of the I-3s section that forms the rail 24 (see Fig 2).
3~ The invention is concerned with the manner of attaching the 3e support tubes 27 into the holes 28 in the web 29 of the 39 I-section. Usually, headrests are adjustable as to vertical ao position, and the adjustment is effected by moving the headrest, 4i with its two pegs 26, vertically up or down within the tubes 27.
1 The designer can provide a plastic sleeve 30, which is inserted z into the support tube to provide a bearing for guiding the pegs 3 for up/down adjustment movement. The designer can provide the a pegs with detents (not shown), which interact with the plastic s sleeves 30, or with the tubes 27, in order to define some s vertical positions to which the headrest might be set. It is usually necessary to align the plastic sleeve orientationally a with respect to the tube, and the plastic sleeve can be moulded 9 with a tongue for engagement with a notch 32 (Fig 5) in the tube, to for this purpose.
lz In order to manufacture the seat frame, with the headrest support 13 tubes 27 attached, first the tubes are formed with a single first 14 swaged-out ring 34. The tube in this state is as shown in Fig 2.
is The swaged-out ring 34 is formed by pressing the ends of a plain l length of tubing axially, and confining the walls thereof le everywhere but at the place where the ring is to be formed. It 19 may be noted that this first operation is carried out on the tube zo when only the tube itself is present, i.e in the absence of any zl other components. The operation of forming the first ring is of zz low labour content, and can be easily automated.
za The job of attaching the tube 27, with its first swaged-out ring z5 34, into the hole 28 in the web 29 of the I-section, can also be zs fully automated, as can the job of swaging the first ring into z~ the tube. This may be compared with the job of welding a bracket ze onto the frame piece, and then locating a tube into holes in the zs bracket, and then welding the tube to the bracket, in which the 30 labour content is inevitably high.
3z Fig 3 shows the tube 27, with its first swaged-out ring 34;
s3 resting in a die 35. The seat frame piece 23 has been placed 3a over the tube 27, with the web 29 resting against the first ring 3s 34. A punch 36 is advanced, and a hole 37 in the punch slides 3s over the upper portion of the tube 27. When the end of the hole 3~ 38 bottoms against the end 39 of the tube 27, further movement of 3a the punch causes the upper portion of the tube to be compressed.
3s A recess 40 in the punch allows the metal of the tube to expand 40 outwards, in response to the axial force, with the result that al the action of the punch causes a second ring 42 to be formed in 1 the tube.
z s Fig 4 shows the situation when the punch and die are (almost) 4 closed fully together. It will be seen from Fig 4 that the web s 29 is not contacted by either the die 35 or the punch 36 during 6 the operation of swaging out the second ring 42. At the very end of the operation, the designer might provide that the web is in a fact subjected to a squeeze between the punch and die, as a s coining phase to ensure everything is straight; but in general, to throughout the pressing stages indicated in Figs 3 and 4, the web l 29 floats. As the pressing operation is nearing completion, the lz press forces also act on the first ring 34, and cause that to be 13 consolidated and even coined.
is The hole 28 in the frame piece is a clearance fit over the is diameter of the tuba 27, and so the frame-piece is not held in position, during the Fig 4 operation, by being held by a tight is fit on the tube 27. Therefore, the frame-piece 23 does need to is be held -- at least loosely -- to prevent tipping thereof.
zo However, that kind of holding is simple enough -- at least when zl compared with securing the components in welding jigs.
zz z3 It is important, during the Fig 4 pressing operation, that the z4 web 29 remain resting in close touching contact with the first zs ring 34. In an automated system, the designer should ensure that z6 the components are presented properly to each other for the z~ operation. Seat-frame-pieces can include bends and twists, and ze be of an awkward shape, but the designer can provide the holding-zs clamps etc to accommodate whatever shape the seat-frame-pieces so are in. The designer can decide whether to insert the head-rest-31 support-tubes into the seat-frame-piece before or after the seat-3z frame-piece is bent and twisted to its final shape.
34 The designer should ensure that, whatever the configuration of 35 the components, the web can and does rest properly (i.e in firm 3s abutment) against the first ring during the operation of pressing the second ring: if there were to be some clearance between the 3a web and the first ring during pressing, the final joint would be 3s significantly less tight and secure. The ideal is that the web 4o should be under some degree of residual compression after the al punch and die have separated, even if only slightly, and that can 1 only happen if the web remains cleanly in abutment against the z first ring throughout the pressing operation.
4 In an alternative, the die and punch set may be arranged with a s subsidiary actuable member, which loads the web tightly against s the first ring while the forming of the second ring is taking place.
a s It is important also that the clearance between the hole 28 in to the web and the diameter of the tube 27 be taken up during the l pressing operation. The force that causes the metal of the tube lz to swell out to form the second ring 42, of course also causes 13 the metal to swell out to fill the clearance at the hole 28.
i4 Generally, the filling of the hole 28 is so good that any is crannies etc caused by burrs or other malformations arising from is the punching of the hole 28, are filled completely and tightly.
la The manner as described above of attaching the headrest support 19 tubes to the seat frame provides a very secure attachment, which 2o is amply able to accommodate the forces and abusive forces zl encountered in automotive seating equipment. The material costs 22 are somewhat reduced, and the labour costs are very much reduced, 23 as compared with what has to be done in the conventional tasks of z4 welding the tubes to the frames.
zs It is conventional for the frames of automobile seats to be made z~ from steel tubing. The head-rest-support-posts can be attached za into a tubular-steel seat-frame in the manner as will now be 29 described.
31 Figs 6a,6b,6c are views directed axially along the length of the 3z seat-frame-tube 50, and show three stages in the preparation of 33 the seat-frame-tube. Figs 7a,7c are views corresponding to Figs 34 6a,6c in the direction of arrows 7-7 of Fig 6a.
ss In Fig 6a, the seat-frame-tube 50 has been gripped on its outside 3~ diameter between two dies 52x,52y. The dies are dimensioned to 3a grip the seat-frame-tube at two spaced locations 53,54. The dies 3s 52x,52y are shaped so as not to directly grip the seat-frame-tube 50 in the recess 55 between the locations 53,54.
1 Once the dies 52x,52y are in contact, and the seat-frame-tube 50 2 is firmly held, the two formers 56x,56y are advanced. At first, 3 the seat-frame-tube 50 is flattened, as shown in Fig 6b. As the 4 upper and lower zones 57x,57y of the tube walls are forced together, the left and right side-zones 58L,58R are forced apart, s and these zones of the walls come into contact with the sides 59L,59R of the recess 55.
a s The formers 56x,56y are advanced until they bottom against the io two thicknesses of the wall-zones 57x,57y, as shown in Figs 11 6c,7c. The wall-zones 58L,58R are formed to the shape as shown iz by virtue of their confinement by the sides 59L,59R of the recess i3 55. It will be noted that this manner of forming the seat-frame-i4 tube produces a localised shape which is similar to that of an I-is beam. The web 60 of the I-beam shape is derived from the wall-is zones 57x,57y, and the flanges 62L,62R of the I-beam are derived from the folded wall-zones 58L,58R.
is ~s It is noted that the seat-frame-tube 50 is not simply squashed zo flat. The operations as described produce a configuration that zi is much stronger and more rigid than a flattened tube. The 22 flanges 62L,62R, being tall (i.e the height of the flanges is 23 equal to several thicknesses of the walls of the tube), are 2a crucial to the rigidity of the tube against bending forces, which 25 of course is an important consideration in a seat frame.
2~ A hole 63 for receiving the head-rest-support-tube is punched in 2a the web 60 of the seat-frame-tube, in the manner as shown in Figs is 8a,8b. A die-button 64 is brought into contact with one side of 3o the web 60. A punch 65, carried in a stripper 67, is advanced, 3i and pierces the hole 63 in the web. The die-button 64 and the 32 stripper 67 are dimensioned to hold the web 60 to its desired 33 shape during the disruption caused by the punching operation and 34 subsequent stripping of the web from the punch 65.
36 The head-rest-support-tube 68 that is to be secured into the hole 3~ 63 in the web 60 is shown in Fig 9. The head-rest-support-tube 3a 68 is of steel, and includes an upper section 69, in which is cut 39 a notch 70, a first ring-bead 72, and a lower section 73, the ao bottom section 74 of which is swaged down to a slightly smaller 41 diameter than the rest of the head-rest-support-tube. The inside 1 diameter of the bottom section 74 is dimensioned to be a tight z location-fit on the peg 26 of the head-rest, and the reduced 3 outside diameter of the bottom section 74 ensures an easy 4 placement of the head-rest-support-tube 68 into the hole 63 in s the web 60 of the seat-frame-tube 50.
The manner of installing the head-rest-support-tube 68 into the a hole 63 is illustrated in Figs lOa,lOb,lOc. The head-rest-9 support-tube is first positioned into a punch unit 75. The top to end 76 of the head-rest-support:-tube abuts against a shoulder 78 11 of the punch 79, and the already-formed first ring-bead 72 abuts lz against the bottom face of the punch-holder 80.
14 As shown in Fig 10b, the head-rest -support-tube passes through is the hole 63, and the tapered bottom end of the head-rest-support-16 tube enters the recess 82 in the die 83. As the punch 75 and die 1~ 83 approach, the bottom end of the head-rest-support-tube abuts la against the bottom of the recess 82. From then on, further 19 approaching movement of the punch and die are reacted as an zo axially-directed compressive force on the head-rest-support-tube.
zl The compressive force is enough the cause the walls of the head-zz rest-support-tube to buckle outwards, whereby the second ring-23 bead 84 is formed. Approaching movement of the punch and die z4 continues until the. condition of Fig lOc is reached.
zs zs The punch and die are then withdrawn, and the seat-frame-tube 50, z~ with the head-rest-support-tube 68 now firmly attached, can be ze transferred to the next stage in the manufacture of the seat.
3o The manner of attaching the head-rest-support -tube into the seat-31 frame-tube ensures that the web 60 is structurally unitary with 3z the head-rest-support-tube. The first and second ring-beads 33 72,84 grip the web between them, providing a secure base for 34 resisting abusive forces from any direction, which might tend to 3s disrupt the attachment.
By forcing the punch unit 75 and the die 83 hard together 3e (Fig lOc) the amount of spring-back upon release can be made very 39 small, whereby the compressive grip on the web is still firmly 4o present upon release.
l0 1 The head-rest-support-tube might be subjected to forces tending 2 to rotate it, during use of the: automobile, and it is important 3 that rotation forces are resisted. If rotation of the head-rest-4 support-tube were to be permitted, the movement might cause the s attachment to rattle or work loose. Accordingly, the designer s might prefer to make the hole 63 in the web slightly non-circular. In fact, given the f act that the hole occupies a large s area of the tube, it is all toc> easy for the hole 63 to be non-circular in any event. The operation of forming the second ring-lo bead 84, however, ensures that the head-rest-support-tube adapts 11 itself completely to whatever out-of-roundness there might be in 12 the hole 63, which helps to ensure freedom from rotation of the is head-rest-support-tube.
is The attachment system as described is very strong, as compared is with the conventional welded construction, but apart from that 1~ clear advantage, the attachment system provides excellent and is repeatable accuracy. Now that accuracy of alignment of the two is head-rest-support-tubes can be relied upon, the design of the 2o head-rest detents can be free of the compromises needed with the 21 conventional welded attachment; designing a detent is a matter of 2z making sure the force to move the head-rest pegs against the 23 detent is neither too light nor too heavy, and the more 24 accurately the components can be positioned, the easier it is to 2s ensure the correct force.
2~ Not only is the attachment system as described very strong, and 2a accurate, but the system also lends itself to full automation.
2s The attachment system is in keeping with the kinds of operations so that have to be carried out on seat-frame-tubes, such as bending, sl piercing, etc, and the machinery for automating such operations 32 is already commonplace. The similarity of those frame-tube 33 operations with the operations required in the attachment system 34 will be clear: the dis-similarity of the frame-tube operations 3s with the conventional welding attachment system, is even more ss clear.
l0a "The expressions upper, lower, horizontal, vertical, etc, as used in this specification, should not be interpreted to mean that the invention only applies when the actual physical components used in operating the invention are orientated in only that way.
Rather, the expressions should be taken as referring to those directions when the components are represented on paper, which is oriented accordingly."
12 Support tubes for headrests are conventionally attached to the 13 seat frame piece by welding a bracket onto the frame piece, and 14 then welding the tube to the bracket. Sometimes, the tube is is pressed into holes in the welded-on bracket; but welding is is nearly always resorted to, to assure that the tube remains in 1~ position on the bracket. Of course, the tubes can be attached is securely enough, but the conventional costs of ensuring that 19 security are high.
2z GENERAL FEATURES OF THE INVENTION
24 The invention lies in the manner of attaching the headrest-2s support-tube. First, the headrest-support-tube is provided with zs a first ring, in which the metal of the headrest-support-tube is z~ expanded radially outwards. The headrest-support-tube is zs assembled into a hole in the web of the seat-frame-piece, with 29 the first ring abutting against the web.
31 The frame-piece, with the headrest-support-tube resting therein, 32 is placed in the die of a punch and die set, with the first ring 33 in the die. The punch then is brought down over the other end of 34 the headrest-support-tube, and a second ring is formed on the 3s other side of the web. When the punch is withdrawn, the web lies 3s gripped between the two rings. Usually, another headrest-3~ support-tube is inserted into the frame-piece, in a similar 3s manner. Then, the seat-frame p:'tece is assembled into a seat, and 39 finally the pegs of the headrest are inserted into the headrest-4o support-tubes.
i THE PRIOR ART
z 3 As mentioned, headrest-support tubes are attached to the seat-4 frame-piece by welding. Sometimes, designers have specified s intermediate brackets, rather than just welding the tube to the 6 frame piece.
a Techniques for mounting a tube into a through-hole in a piece of 9 sheet metal are commonplace, per se. The broad range of options io available include bulk-head fittings generally. Such fittings 11 have included cases where a first bead is provided on the tube on iz one side of the sheet, then a second bead is swaged into the tube i3 after the tube has been inserted into the through-hole. The 14 technique is commonly known as lock-beading.
is is In cases where bulk-head fittings are being designed, a common m requirement is that the fitting' by air- or liquid-tight. It is is recognised that the lock-beading technique is not suitable for is such cases. It is recognised that lock-beading is highly 2o suitable for cases where mechanical integrity is paramount, zi rather than sealing. It is also recognised that lock-beading is 22 highly suitable for cases where access to the beads is only to be 23 had from an axial direction, such as a case where flat-access to z4 the through-hole is denied because the through-hole is surrounded is by raised flanges.
za DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
3o By way of further explanation of the invention, exemplary 3i embodiments of the invention will now be described with reference 32 to the accompanying drawings, in which:
34 Fig 1 is a diagram of an automobile seat frame, shown partly in 3s cross-section, carrying a headrest which is mounted in a 36 manner in accordance with the invention;
37 Fig 2 is a view of some of the components that support the 3a headrest, shown at a preliminary stage of manufacture;
39 Fig 3 is a view of a punch and die set-up, which is used at a ao stage in the manufacture of one of the headrest supports;
41 Fig 4 is a view corresponding to Fig 3 of another stage during manufacture;
2 Fig 5 is a cross-section of the headrest mounting support, shown at a later stage;
a Figs 6a,6b,6c are cross-sections of a tooling arrangement for s forming a metal tube locally into an I-section beam;
s Figs 7a,7c are views on the line 7-7 of Fig 6a, corresponding to the conditions shown in Figs 6a and 6c respectively;
a Figs 8a,8b are cross-sections of a hole-punching arrangement, for making a through-hole in l:he web of the I-beam produced as to in Fig 6c;
m Fig 9 is a view of a headrest-support-tube, shown prior to final iz forming;
i3 Figs lOa,lOb,lOc are cross-sections of a tooling arrangement for i4 ring-bead-locking the headrest-support-tube of Fig 9 into is the through-hole in the web of the I-beam.
is m The apparatuses shown in the accompanying drawings and described is below are examples which embody the invention. It should be i9 noted that the scope of the invention is defined by the zo accompanying claims, and not necessarily by specific features of 2i exemplary embodiments.
z3 Fig 1 shows an automobile seat 20, having a seat frame piece 23.
2a In this case, the seat frame piece 23 made from a length of 2s extruded I-section aluminum. The seat frame piece is bent 2s generally into an inverted U-shape, as shown, in which the z7 horizontal rail 24 of the U-shape forms the horizontal top rail ze of the seat.
3o The headrest 25 of the seat 20 .is formed with two pegs 26, which 3i protrude downwards, as shown. ~.rhe pegs engage into support tubes 3z 27, which are integral with the frame of the seat. The support 33 tubes 27 are fixed firmly to the horizontal rail 24, and in fact 34 the support tubes pass through holes 28 in the web 29 of the I-3s section that forms the rail 24 (see Fig 2).
3~ The invention is concerned with the manner of attaching the 3e support tubes 27 into the holes 28 in the web 29 of the 39 I-section. Usually, headrests are adjustable as to vertical ao position, and the adjustment is effected by moving the headrest, 4i with its two pegs 26, vertically up or down within the tubes 27.
1 The designer can provide a plastic sleeve 30, which is inserted z into the support tube to provide a bearing for guiding the pegs 3 for up/down adjustment movement. The designer can provide the a pegs with detents (not shown), which interact with the plastic s sleeves 30, or with the tubes 27, in order to define some s vertical positions to which the headrest might be set. It is usually necessary to align the plastic sleeve orientationally a with respect to the tube, and the plastic sleeve can be moulded 9 with a tongue for engagement with a notch 32 (Fig 5) in the tube, to for this purpose.
lz In order to manufacture the seat frame, with the headrest support 13 tubes 27 attached, first the tubes are formed with a single first 14 swaged-out ring 34. The tube in this state is as shown in Fig 2.
is The swaged-out ring 34 is formed by pressing the ends of a plain l length of tubing axially, and confining the walls thereof le everywhere but at the place where the ring is to be formed. It 19 may be noted that this first operation is carried out on the tube zo when only the tube itself is present, i.e in the absence of any zl other components. The operation of forming the first ring is of zz low labour content, and can be easily automated.
za The job of attaching the tube 27, with its first swaged-out ring z5 34, into the hole 28 in the web 29 of the I-section, can also be zs fully automated, as can the job of swaging the first ring into z~ the tube. This may be compared with the job of welding a bracket ze onto the frame piece, and then locating a tube into holes in the zs bracket, and then welding the tube to the bracket, in which the 30 labour content is inevitably high.
3z Fig 3 shows the tube 27, with its first swaged-out ring 34;
s3 resting in a die 35. The seat frame piece 23 has been placed 3a over the tube 27, with the web 29 resting against the first ring 3s 34. A punch 36 is advanced, and a hole 37 in the punch slides 3s over the upper portion of the tube 27. When the end of the hole 3~ 38 bottoms against the end 39 of the tube 27, further movement of 3a the punch causes the upper portion of the tube to be compressed.
3s A recess 40 in the punch allows the metal of the tube to expand 40 outwards, in response to the axial force, with the result that al the action of the punch causes a second ring 42 to be formed in 1 the tube.
z s Fig 4 shows the situation when the punch and die are (almost) 4 closed fully together. It will be seen from Fig 4 that the web s 29 is not contacted by either the die 35 or the punch 36 during 6 the operation of swaging out the second ring 42. At the very end of the operation, the designer might provide that the web is in a fact subjected to a squeeze between the punch and die, as a s coining phase to ensure everything is straight; but in general, to throughout the pressing stages indicated in Figs 3 and 4, the web l 29 floats. As the pressing operation is nearing completion, the lz press forces also act on the first ring 34, and cause that to be 13 consolidated and even coined.
is The hole 28 in the frame piece is a clearance fit over the is diameter of the tuba 27, and so the frame-piece is not held in position, during the Fig 4 operation, by being held by a tight is fit on the tube 27. Therefore, the frame-piece 23 does need to is be held -- at least loosely -- to prevent tipping thereof.
zo However, that kind of holding is simple enough -- at least when zl compared with securing the components in welding jigs.
zz z3 It is important, during the Fig 4 pressing operation, that the z4 web 29 remain resting in close touching contact with the first zs ring 34. In an automated system, the designer should ensure that z6 the components are presented properly to each other for the z~ operation. Seat-frame-pieces can include bends and twists, and ze be of an awkward shape, but the designer can provide the holding-zs clamps etc to accommodate whatever shape the seat-frame-pieces so are in. The designer can decide whether to insert the head-rest-31 support-tubes into the seat-frame-piece before or after the seat-3z frame-piece is bent and twisted to its final shape.
34 The designer should ensure that, whatever the configuration of 35 the components, the web can and does rest properly (i.e in firm 3s abutment) against the first ring during the operation of pressing the second ring: if there were to be some clearance between the 3a web and the first ring during pressing, the final joint would be 3s significantly less tight and secure. The ideal is that the web 4o should be under some degree of residual compression after the al punch and die have separated, even if only slightly, and that can 1 only happen if the web remains cleanly in abutment against the z first ring throughout the pressing operation.
4 In an alternative, the die and punch set may be arranged with a s subsidiary actuable member, which loads the web tightly against s the first ring while the forming of the second ring is taking place.
a s It is important also that the clearance between the hole 28 in to the web and the diameter of the tube 27 be taken up during the l pressing operation. The force that causes the metal of the tube lz to swell out to form the second ring 42, of course also causes 13 the metal to swell out to fill the clearance at the hole 28.
i4 Generally, the filling of the hole 28 is so good that any is crannies etc caused by burrs or other malformations arising from is the punching of the hole 28, are filled completely and tightly.
la The manner as described above of attaching the headrest support 19 tubes to the seat frame provides a very secure attachment, which 2o is amply able to accommodate the forces and abusive forces zl encountered in automotive seating equipment. The material costs 22 are somewhat reduced, and the labour costs are very much reduced, 23 as compared with what has to be done in the conventional tasks of z4 welding the tubes to the frames.
zs It is conventional for the frames of automobile seats to be made z~ from steel tubing. The head-rest-support-posts can be attached za into a tubular-steel seat-frame in the manner as will now be 29 described.
31 Figs 6a,6b,6c are views directed axially along the length of the 3z seat-frame-tube 50, and show three stages in the preparation of 33 the seat-frame-tube. Figs 7a,7c are views corresponding to Figs 34 6a,6c in the direction of arrows 7-7 of Fig 6a.
ss In Fig 6a, the seat-frame-tube 50 has been gripped on its outside 3~ diameter between two dies 52x,52y. The dies are dimensioned to 3a grip the seat-frame-tube at two spaced locations 53,54. The dies 3s 52x,52y are shaped so as not to directly grip the seat-frame-tube 50 in the recess 55 between the locations 53,54.
1 Once the dies 52x,52y are in contact, and the seat-frame-tube 50 2 is firmly held, the two formers 56x,56y are advanced. At first, 3 the seat-frame-tube 50 is flattened, as shown in Fig 6b. As the 4 upper and lower zones 57x,57y of the tube walls are forced together, the left and right side-zones 58L,58R are forced apart, s and these zones of the walls come into contact with the sides 59L,59R of the recess 55.
a s The formers 56x,56y are advanced until they bottom against the io two thicknesses of the wall-zones 57x,57y, as shown in Figs 11 6c,7c. The wall-zones 58L,58R are formed to the shape as shown iz by virtue of their confinement by the sides 59L,59R of the recess i3 55. It will be noted that this manner of forming the seat-frame-i4 tube produces a localised shape which is similar to that of an I-is beam. The web 60 of the I-beam shape is derived from the wall-is zones 57x,57y, and the flanges 62L,62R of the I-beam are derived from the folded wall-zones 58L,58R.
is ~s It is noted that the seat-frame-tube 50 is not simply squashed zo flat. The operations as described produce a configuration that zi is much stronger and more rigid than a flattened tube. The 22 flanges 62L,62R, being tall (i.e the height of the flanges is 23 equal to several thicknesses of the walls of the tube), are 2a crucial to the rigidity of the tube against bending forces, which 25 of course is an important consideration in a seat frame.
2~ A hole 63 for receiving the head-rest-support-tube is punched in 2a the web 60 of the seat-frame-tube, in the manner as shown in Figs is 8a,8b. A die-button 64 is brought into contact with one side of 3o the web 60. A punch 65, carried in a stripper 67, is advanced, 3i and pierces the hole 63 in the web. The die-button 64 and the 32 stripper 67 are dimensioned to hold the web 60 to its desired 33 shape during the disruption caused by the punching operation and 34 subsequent stripping of the web from the punch 65.
36 The head-rest-support-tube 68 that is to be secured into the hole 3~ 63 in the web 60 is shown in Fig 9. The head-rest-support-tube 3a 68 is of steel, and includes an upper section 69, in which is cut 39 a notch 70, a first ring-bead 72, and a lower section 73, the ao bottom section 74 of which is swaged down to a slightly smaller 41 diameter than the rest of the head-rest-support-tube. The inside 1 diameter of the bottom section 74 is dimensioned to be a tight z location-fit on the peg 26 of the head-rest, and the reduced 3 outside diameter of the bottom section 74 ensures an easy 4 placement of the head-rest-support-tube 68 into the hole 63 in s the web 60 of the seat-frame-tube 50.
The manner of installing the head-rest-support-tube 68 into the a hole 63 is illustrated in Figs lOa,lOb,lOc. The head-rest-9 support-tube is first positioned into a punch unit 75. The top to end 76 of the head-rest-support:-tube abuts against a shoulder 78 11 of the punch 79, and the already-formed first ring-bead 72 abuts lz against the bottom face of the punch-holder 80.
14 As shown in Fig 10b, the head-rest -support-tube passes through is the hole 63, and the tapered bottom end of the head-rest-support-16 tube enters the recess 82 in the die 83. As the punch 75 and die 1~ 83 approach, the bottom end of the head-rest-support-tube abuts la against the bottom of the recess 82. From then on, further 19 approaching movement of the punch and die are reacted as an zo axially-directed compressive force on the head-rest-support-tube.
zl The compressive force is enough the cause the walls of the head-zz rest-support-tube to buckle outwards, whereby the second ring-23 bead 84 is formed. Approaching movement of the punch and die z4 continues until the. condition of Fig lOc is reached.
zs zs The punch and die are then withdrawn, and the seat-frame-tube 50, z~ with the head-rest-support-tube 68 now firmly attached, can be ze transferred to the next stage in the manufacture of the seat.
3o The manner of attaching the head-rest-support -tube into the seat-31 frame-tube ensures that the web 60 is structurally unitary with 3z the head-rest-support-tube. The first and second ring-beads 33 72,84 grip the web between them, providing a secure base for 34 resisting abusive forces from any direction, which might tend to 3s disrupt the attachment.
By forcing the punch unit 75 and the die 83 hard together 3e (Fig lOc) the amount of spring-back upon release can be made very 39 small, whereby the compressive grip on the web is still firmly 4o present upon release.
l0 1 The head-rest-support-tube might be subjected to forces tending 2 to rotate it, during use of the: automobile, and it is important 3 that rotation forces are resisted. If rotation of the head-rest-4 support-tube were to be permitted, the movement might cause the s attachment to rattle or work loose. Accordingly, the designer s might prefer to make the hole 63 in the web slightly non-circular. In fact, given the f act that the hole occupies a large s area of the tube, it is all toc> easy for the hole 63 to be non-circular in any event. The operation of forming the second ring-lo bead 84, however, ensures that the head-rest-support-tube adapts 11 itself completely to whatever out-of-roundness there might be in 12 the hole 63, which helps to ensure freedom from rotation of the is head-rest-support-tube.
is The attachment system as described is very strong, as compared is with the conventional welded construction, but apart from that 1~ clear advantage, the attachment system provides excellent and is repeatable accuracy. Now that accuracy of alignment of the two is head-rest-support-tubes can be relied upon, the design of the 2o head-rest detents can be free of the compromises needed with the 21 conventional welded attachment; designing a detent is a matter of 2z making sure the force to move the head-rest pegs against the 23 detent is neither too light nor too heavy, and the more 24 accurately the components can be positioned, the easier it is to 2s ensure the correct force.
2~ Not only is the attachment system as described very strong, and 2a accurate, but the system also lends itself to full automation.
2s The attachment system is in keeping with the kinds of operations so that have to be carried out on seat-frame-tubes, such as bending, sl piercing, etc, and the machinery for automating such operations 32 is already commonplace. The similarity of those frame-tube 33 operations with the operations required in the attachment system 34 will be clear: the dis-similarity of the frame-tube operations 3s with the conventional welding attachment system, is even more ss clear.
l0a "The expressions upper, lower, horizontal, vertical, etc, as used in this specification, should not be interpreted to mean that the invention only applies when the actual physical components used in operating the invention are orientated in only that way.
Rather, the expressions should be taken as referring to those directions when the components are represented on paper, which is oriented accordingly."
Claims (4)
- CLAIM 1. Procedure for preparing the top-rail of an automobile seat frame for the attachment thereto of a headrest-support-tube, wherein the top-rail comprises a hollow metal seat-tube, and the procedure includes the following steps:
providing a die-set, and securing the seat-tube therein, oriented in a horizontal sense;
wherein the die-set includes formers, which are so shaped that, when the formers are brought together in a vertical direction, the formers squeeze opposed upper and lower zones of the wall of the seat-tube together, to form a walls-touching-area of the top-rail;
wherein the formers are so shaped that, when the formers are brought together in a vertical direction, left and right side-zones of the seat-tube walls remain clear of the former in the vertical sense, and the left and right side-zones of the seat-tube wall are thereby not squeezed together in the vertical sense, but are left substantially upstanding;
forcing the formers together, whereby the subsequent cross-sectional configuration of the upstanding left and right side-zones of the seat-tube wall, in relation to the walls-touching-area of the seat-tube wall, is that of an I-beam, having left and right side-flanges and a web straddling therebetween;
after the upper and lower portions of the seat-tube wall have been squeezed together, over the walls-touching-area of the seat-tube, the step of then making a hole right through the walls-touching-area, the through-hole being through both the upper and lower zones of the seat-tube wall;
and inserting the headrest-support-tube in the through-hole. - Claim 2. Procedure of claim 1, wherein the formers are so structured, and are so arranged in the punch and die set, that the walls-touching-area of the top-rail is localised to a zone of the top-rail that is marginal to the headrest-support-tube, and the remainder of the seat-tube beyond the said marginal zone remains substantially un-compressed.
- Claim 3. Procedure of claim 2, including the step of making the through-hole by punching.
- Claim 4. Procedure of claim 3, wherein the die-set includes a hole-punch for punching the through-hole, and the hole-punch is located concentrically inside one of the formers.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GBGB9708394.3A GB9708394D0 (en) | 1997-04-25 | 1997-04-25 | Securement of head rest support into automobile seat frame |
| GB9708394.3 | 1997-04-25 |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2235636 Division CA2235636C (en) | 1997-04-25 | 1998-04-23 | Securement of head rest support into automobile seat frame |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2328857A1 CA2328857A1 (en) | 1998-10-25 |
| CA2328857C true CA2328857C (en) | 2002-09-17 |
Family
ID=10811339
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2328857 Expired - Fee Related CA2328857C (en) | 1997-04-25 | 1998-04-23 | Securement of head rest support into automobile seat frame |
| CA 2235636 Expired - Fee Related CA2235636C (en) | 1997-04-25 | 1998-04-23 | Securement of head rest support into automobile seat frame |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2235636 Expired - Fee Related CA2235636C (en) | 1997-04-25 | 1998-04-23 | Securement of head rest support into automobile seat frame |
Country Status (1)
| Country | Link |
|---|---|
| CA (2) | CA2328857C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2370811A1 (en) | 2002-02-06 | 2003-08-06 | Bill Frenke | Seat frame structure and method for forming |
-
1998
- 1998-04-23 CA CA 2328857 patent/CA2328857C/en not_active Expired - Fee Related
- 1998-04-23 CA CA 2235636 patent/CA2235636C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2328857A1 (en) | 1998-10-25 |
| CA2235636C (en) | 2002-10-15 |
| CA2235636A1 (en) | 1998-10-25 |
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| Date | Code | Title | Description |
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| EEER | Examination request | ||
| MKLA | Lapsed |