CA1059554A - Energy absorbing cellular matrix for vehicles with plural working zones - Google Patents
Energy absorbing cellular matrix for vehicles with plural working zonesInfo
- Publication number
- CA1059554A CA1059554A CA261,414A CA261414A CA1059554A CA 1059554 A CA1059554 A CA 1059554A CA 261414 A CA261414 A CA 261414A CA 1059554 A CA1059554 A CA 1059554A
- Authority
- CA
- Canada
- Prior art keywords
- matrix
- cells
- wall means
- walls
- tapering
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Vibration Dampers (AREA)
Abstract
ENERGY ABSORBING CELLULAR MATRIX FOR
VEHICLES WITH PLURAL WORKING ZONES
Abstract of the Disclosure Soft face bumper for vehicles incorporating a resil-ient energy absorbing cellular matrix molded from plastic material in which the walls of longitudinally extending cells taper from minimum thicknesses at opposite ends thereof to a maximum thickness at a parting line intermediate the ends.
With double tapered walls, each cell has at least two sepa-rate working zones which preferably deflect simultaneously to optimize energy absorption. With draft angle of the cell walls effectively reduced by this construction a savings in weight, material and molding cycle time is provided.
VEHICLES WITH PLURAL WORKING ZONES
Abstract of the Disclosure Soft face bumper for vehicles incorporating a resil-ient energy absorbing cellular matrix molded from plastic material in which the walls of longitudinally extending cells taper from minimum thicknesses at opposite ends thereof to a maximum thickness at a parting line intermediate the ends.
With double tapered walls, each cell has at least two sepa-rate working zones which preferably deflect simultaneously to optimize energy absorption. With draft angle of the cell walls effectively reduced by this construction a savings in weight, material and molding cycle time is provided.
Description
**********
This invention relates to absorption of impact energ~
and more particularly to a resilient energy absorbing matrix for vehicles having longitudinally e:~t~nding cells formed from a lattic~ork of intersecting walls which taper from an inter-mediate parting line to the outer and inner ends of the cells to provide a new and improved energy management medium.
Prior to the present invention soft face energy absorbers for vehicle application such as for front and rear bumpers have been made from resilient plastic materials and injection molded to have longitudinally extending cells. The cells of these energy absorbers as usually installed are gen-erally parallel to the longitudinal axis of the vehicle. On impact of sufficient magnitude the walls of these cells twist and buckle to absorb impact energy. on removal of the impact load the cell walls gradually recover toward tlleir original configuration, usually with no apparent damaga. Generally the ~r . .
. . . . . . . . . . . . . .
~ -- .
;.. . . ~ . . . . ..
.
lOS9SSq~
cells of these prior energy absorbers have walls with a draft angle which taper from a minimum thickness at one end of the cells to a maximum thickness of the other end of the cells.
In cross-section, the walls of each cell have a wedge ox triangle-like formation. This construction results from the draft of the mold cores to facilitate ejection of the cellular matrix from the mold. In such an energy absorbing construction the thinner wall portion of the cells tend to deflect and knee-over before the thick wall portions of the cell so that in most impact situations only a limited portion of the impacted cells are worked to absorb impact energy. Generally the thick wall portions of the impacted cells remain undeflected and, there-fore, ineffective for energy absorption.
In this invention the energy absorber is molded with a split core mold, i.e., with mold cores extending from both sides and meeting at a parting line, to provide a multicelled energy absorbing matrix. The walls of the cells of this matrix taper from a minimum thickness at either end thereof to a maximized thickness at the parting line intermediate the ends of the cells. The cross-sectional configuration of such walls is generally diamond shaped so that longitudinally extending inner and outer portions of each cell of the matrix as deter-mined by the parting line form separate working zones which buckle on impact. While the walls forming one zone may have a thickness and draft angle different from the walls of the other zone for tailoring the energy absorbing capability of the matrix, it is generally the object of this invention to provide a new and improved energy absorber with generally parallel open cells which deflect from both ends on impact so that more effective use is made of the energy absorbing abili~y of multi-.. - , . - .
1055~554 celled mediums. By appropriately changing the core heights in the mold, the working zone depths of the cells can be changed from equal to unequal zones to meet design and energy management requirements. With the cells having walls which progressively reduce in thickness from a maximized inter-mediate thickness, a new and improved energy absorber cellu-lar construction is provided which has reduced weight and increased efficiency as compared to prior art multicelled units. With the double tapered cellular walls, a new and improved multicelled and molded energy absorbing unit is provided which can be readily formed and easily removed from the mold in a short cycle time. This invention provides for saving in material and production costs. Additionally, this invention provides for increased design flexibility with added numbers of variable parameters such as having double wall thicknesses, two draft angles and two core heights.
These and other features, objects and advantages of this invention will be more apparent from the following detailed description and drawing in which: ~ -FIGURE 1 is a perspective view, with parts broken away, of the preferred embodiment of this invention.
FIGURE 2 is an enlarged view of a portion of FIGURE
1. .
FIGURE 3 is a cross-sectional view taken along line ; 3-3 of FIGURE 2.
FIGURE 4 is a plot of force versus deflection illustrating operation of this invention.
Turning now in greater detail to the drawing, there is diagrammatically shown in FIGURE 1 a vehicle bumper assem-bly 10 having a resilient energy absorbing matrix 12 formed ~o595~4 from a suitable thermoplastic material such as a blencled olefin. The matrix 12 has a plurality of longitudinally extending and generally parallel cells 14 open throughout their length which are formed by a latticework of inter-secting horizontal and vertical]y extending walls 16 and 18. As best shown in FIGURES 2 and 3 the horizontal and vertical walls 16 and 18 of the cells 14 taper from a maximum thickness at a centralized split or dividing line 20 intermediate the ends thereof to a minimized thickness at their respective outer and inner ends. Thus, horizontal walls 16 have a maximum thickness at split line 20 and taper fr~ this line to a minimum thickness on the outer and inner ends 24 and 26 respectively. Vertical walls 18 have a maximum thickness at the split line 20 and taper from this line to a minimum thickness at their respective inner and outer ends 28 and 30. With this tapered construction, each cell will have outer and inner deflecting zones Zl and Z2 illustrated best in FIGURE 3.
In the preferred embodiment of the invention shown in FIGURE 1, the matrix 12 has an arcuate outer end surface but this surface may be styled to have other configurations as desired. Preferably, the inner and end surface of matrix 12 is flat to seat against a substantially rigid backing beam 32 which is suitable secured to the side rails of a frame of a vehicle which is not shown. Additionally any suitable fastener means may be employed to secure the energy absorbing matrix to the bumper beam. For example, some of the cells 14 can be modified and formed with integral end walls for receiving fastener means such as described in copending United States Patent No. 3,926,463 to DeWayne A. Landwehr et al for Energy Absorbing Cellular Grid for Vehicles issued December 16, 1975. ~lso, to provide a finely finished vehicle appearance a resilient plastic facia 36 may be employed to cover the matrix as described in the above-identified application. Attachment of the facia to the vehicle body work and to the matrix 12, if desired, can be any suitable fastener means.
In operation, assuming the energy absorbing unit is impacted at a low vehicle speed, such as 5mph, the inner and outer wall portions of the cells in the impact area will simultaneously deflect to absorb im-pact energy. With both inner and outer zones deflecting, energy absorbing efficiency is improved as compared to prior art units having cell walls that taper in thickness ;
progressively from one end to the other. This is illus-trated in the force versus deflection plots of FIGURE 4.
Full line curve C represents the force deflection curve of the cellular matrix of this inventioh and it will be -seen that with both zines Zl and Z2 active the ideal square wave force deflection curve D is approached. The energy managed by resilient media is the work done in deforming or compressing the media and, in the case of this invention is represented by the area under curve C. This area is larger than the area under dashed-line curve-E which represents the force deflection of prior art cellular energy absorbing media. Accordingly, there is increased energy absorption potential with this invention with im-proved efficiency as compared to conventional prior art medai with longitudinally extending cells. After removal of the impact load, the cell walls of this invention gradually recover toward their original configuration so that the facia is filled out and backed for subsequent impact loads.
~0$~55~
If desired, the thickness of the Wall9 ~f the cells 14 could be varied to have two different wall thicknesses.
For example, the outer end 30 of the vertical walls 18 may have a thickness greater than the corresponding thickness of the inner end 28. With similar provisions being made for the horizontal walls 16, it will be appreciated that the inner zone Z2 will be of a thinner wall construction as compared to outer zone Z~. With such an arrangement zone Z2 will buckle and deflect at a diferent rate than the outer zone Zl Accordingly, this construction provides new and improved means for tailoring the matrix to absorb impact energy at predeter-mined rates. If desired one zone such as Z2 could be thick walled to have much greater resistance to deflection so that zone Zl would buckle before any appreciable deflection in zone Z2- Thus, a one-piece two-stage energy absorbing matrix is provided for added protection in the event of high speed impacts. While the split line 20 has been shown in the center of the energy absorbing matrix, it can be readily varied to be at any position inwardly or outwardly with respect to the illustrated locationO This requires two different core heights for each cell in forming the split line at other than a central location. In any event tailoring and styling flexi- -bility provided by the dual tapered cells provides increased design potential. This lighter weight cellular construction further improves molding cycle time since the cooiing period after initial in~ection of heated material into the mold is much shorter by virtue of the thinner outer and inner wall portions of each cell.
While a preferred embodiment has been shown and described for purposes of illustrating this invention, other 105~5~
embodiments embodying the concepts of this inVentiGn may be adopted by thos~ skilled in the art, such as falls within the scope of the appended claims.
:;~
.
i''' , , . .
~ ' .
.:
:.,.
.~:
....
'~'":' , ...
','.'`.' ' .
. :- . . .
This invention relates to absorption of impact energ~
and more particularly to a resilient energy absorbing matrix for vehicles having longitudinally e:~t~nding cells formed from a lattic~ork of intersecting walls which taper from an inter-mediate parting line to the outer and inner ends of the cells to provide a new and improved energy management medium.
Prior to the present invention soft face energy absorbers for vehicle application such as for front and rear bumpers have been made from resilient plastic materials and injection molded to have longitudinally extending cells. The cells of these energy absorbers as usually installed are gen-erally parallel to the longitudinal axis of the vehicle. On impact of sufficient magnitude the walls of these cells twist and buckle to absorb impact energy. on removal of the impact load the cell walls gradually recover toward tlleir original configuration, usually with no apparent damaga. Generally the ~r . .
. . . . . . . . . . . . . .
~ -- .
;.. . . ~ . . . . ..
.
lOS9SSq~
cells of these prior energy absorbers have walls with a draft angle which taper from a minimum thickness at one end of the cells to a maximum thickness of the other end of the cells.
In cross-section, the walls of each cell have a wedge ox triangle-like formation. This construction results from the draft of the mold cores to facilitate ejection of the cellular matrix from the mold. In such an energy absorbing construction the thinner wall portion of the cells tend to deflect and knee-over before the thick wall portions of the cell so that in most impact situations only a limited portion of the impacted cells are worked to absorb impact energy. Generally the thick wall portions of the impacted cells remain undeflected and, there-fore, ineffective for energy absorption.
In this invention the energy absorber is molded with a split core mold, i.e., with mold cores extending from both sides and meeting at a parting line, to provide a multicelled energy absorbing matrix. The walls of the cells of this matrix taper from a minimum thickness at either end thereof to a maximized thickness at the parting line intermediate the ends of the cells. The cross-sectional configuration of such walls is generally diamond shaped so that longitudinally extending inner and outer portions of each cell of the matrix as deter-mined by the parting line form separate working zones which buckle on impact. While the walls forming one zone may have a thickness and draft angle different from the walls of the other zone for tailoring the energy absorbing capability of the matrix, it is generally the object of this invention to provide a new and improved energy absorber with generally parallel open cells which deflect from both ends on impact so that more effective use is made of the energy absorbing abili~y of multi-.. - , . - .
1055~554 celled mediums. By appropriately changing the core heights in the mold, the working zone depths of the cells can be changed from equal to unequal zones to meet design and energy management requirements. With the cells having walls which progressively reduce in thickness from a maximized inter-mediate thickness, a new and improved energy absorber cellu-lar construction is provided which has reduced weight and increased efficiency as compared to prior art multicelled units. With the double tapered cellular walls, a new and improved multicelled and molded energy absorbing unit is provided which can be readily formed and easily removed from the mold in a short cycle time. This invention provides for saving in material and production costs. Additionally, this invention provides for increased design flexibility with added numbers of variable parameters such as having double wall thicknesses, two draft angles and two core heights.
These and other features, objects and advantages of this invention will be more apparent from the following detailed description and drawing in which: ~ -FIGURE 1 is a perspective view, with parts broken away, of the preferred embodiment of this invention.
FIGURE 2 is an enlarged view of a portion of FIGURE
1. .
FIGURE 3 is a cross-sectional view taken along line ; 3-3 of FIGURE 2.
FIGURE 4 is a plot of force versus deflection illustrating operation of this invention.
Turning now in greater detail to the drawing, there is diagrammatically shown in FIGURE 1 a vehicle bumper assem-bly 10 having a resilient energy absorbing matrix 12 formed ~o595~4 from a suitable thermoplastic material such as a blencled olefin. The matrix 12 has a plurality of longitudinally extending and generally parallel cells 14 open throughout their length which are formed by a latticework of inter-secting horizontal and vertical]y extending walls 16 and 18. As best shown in FIGURES 2 and 3 the horizontal and vertical walls 16 and 18 of the cells 14 taper from a maximum thickness at a centralized split or dividing line 20 intermediate the ends thereof to a minimized thickness at their respective outer and inner ends. Thus, horizontal walls 16 have a maximum thickness at split line 20 and taper fr~ this line to a minimum thickness on the outer and inner ends 24 and 26 respectively. Vertical walls 18 have a maximum thickness at the split line 20 and taper from this line to a minimum thickness at their respective inner and outer ends 28 and 30. With this tapered construction, each cell will have outer and inner deflecting zones Zl and Z2 illustrated best in FIGURE 3.
In the preferred embodiment of the invention shown in FIGURE 1, the matrix 12 has an arcuate outer end surface but this surface may be styled to have other configurations as desired. Preferably, the inner and end surface of matrix 12 is flat to seat against a substantially rigid backing beam 32 which is suitable secured to the side rails of a frame of a vehicle which is not shown. Additionally any suitable fastener means may be employed to secure the energy absorbing matrix to the bumper beam. For example, some of the cells 14 can be modified and formed with integral end walls for receiving fastener means such as described in copending United States Patent No. 3,926,463 to DeWayne A. Landwehr et al for Energy Absorbing Cellular Grid for Vehicles issued December 16, 1975. ~lso, to provide a finely finished vehicle appearance a resilient plastic facia 36 may be employed to cover the matrix as described in the above-identified application. Attachment of the facia to the vehicle body work and to the matrix 12, if desired, can be any suitable fastener means.
In operation, assuming the energy absorbing unit is impacted at a low vehicle speed, such as 5mph, the inner and outer wall portions of the cells in the impact area will simultaneously deflect to absorb im-pact energy. With both inner and outer zones deflecting, energy absorbing efficiency is improved as compared to prior art units having cell walls that taper in thickness ;
progressively from one end to the other. This is illus-trated in the force versus deflection plots of FIGURE 4.
Full line curve C represents the force deflection curve of the cellular matrix of this inventioh and it will be -seen that with both zines Zl and Z2 active the ideal square wave force deflection curve D is approached. The energy managed by resilient media is the work done in deforming or compressing the media and, in the case of this invention is represented by the area under curve C. This area is larger than the area under dashed-line curve-E which represents the force deflection of prior art cellular energy absorbing media. Accordingly, there is increased energy absorption potential with this invention with im-proved efficiency as compared to conventional prior art medai with longitudinally extending cells. After removal of the impact load, the cell walls of this invention gradually recover toward their original configuration so that the facia is filled out and backed for subsequent impact loads.
~0$~55~
If desired, the thickness of the Wall9 ~f the cells 14 could be varied to have two different wall thicknesses.
For example, the outer end 30 of the vertical walls 18 may have a thickness greater than the corresponding thickness of the inner end 28. With similar provisions being made for the horizontal walls 16, it will be appreciated that the inner zone Z2 will be of a thinner wall construction as compared to outer zone Z~. With such an arrangement zone Z2 will buckle and deflect at a diferent rate than the outer zone Zl Accordingly, this construction provides new and improved means for tailoring the matrix to absorb impact energy at predeter-mined rates. If desired one zone such as Z2 could be thick walled to have much greater resistance to deflection so that zone Zl would buckle before any appreciable deflection in zone Z2- Thus, a one-piece two-stage energy absorbing matrix is provided for added protection in the event of high speed impacts. While the split line 20 has been shown in the center of the energy absorbing matrix, it can be readily varied to be at any position inwardly or outwardly with respect to the illustrated locationO This requires two different core heights for each cell in forming the split line at other than a central location. In any event tailoring and styling flexi- -bility provided by the dual tapered cells provides increased design potential. This lighter weight cellular construction further improves molding cycle time since the cooiing period after initial in~ection of heated material into the mold is much shorter by virtue of the thinner outer and inner wall portions of each cell.
While a preferred embodiment has been shown and described for purposes of illustrating this invention, other 105~5~
embodiments embodying the concepts of this inVentiGn may be adopted by thos~ skilled in the art, such as falls within the scope of the appended claims.
:;~
.
i''' , , . .
~ ' .
.:
:.,.
.~:
....
'~'":' , ...
','.'`.' ' .
. :- . . .
Claims (4)
1. A vehicle bumper comprising a resilient one-piece matrix of plastic material for absorbing vehicle impact energy, said matrix having a plurality of longitudinally extending cells having a polygonal cross section disposed adjacent to each other, said cells being formed by a plurality of substantially thin, flat and angularly disposed walls which intersect one another to form polygonal open cell spaces therebetween which extend un-interrupted between opposite ends of said matrix, a first number of said walls being laterally spaced from each other and tapering from a minimal thickness at opposite ends thereof to a maximum thickness in a plane between the ends thereof, a second number of said walls being vertically spaced from each other and inter-secting said first number of said walls and further tapering from a minimal thickness at opposite ends thereof to a maximum thickness in said plane, a substantially rigid support for said matrix adapted to engage one end of said cells and provide a backing for said matrix to thereby permit said cells to flex from both ends in response to the application of an impact load directed onto the other end of said cells to thereby absorb impact energy.
2. A vehicle bumper comprising a resilient one-piece matrix of plastic material for absorbing energy of an impact load applied thereto, said matrix having a plurality of longi-tudinally extending cells disposed adjacent to each other, said cells being formed by a plurality of substantially thin, flat wall means which intersect one another to form polygonal open spaces therebetween which extend uninterrupted from inner and outer extremities of said matrix, a first number of said wall means being laterally spaced from each other and tapering from a minimal thickness at opposite ends thereof to a maximum thickness in a predetermined plane between the forward and rearward ends of said matrix, a second number of said wall means being angularly disposed with respect to said first number of said wall means and vertically spaced from each other and also tapering from a minimal thickness at opposite ends thereof to a maximum thickness in said predetermined plane between the forward and rearward ends thereof, a support for said matrix adapted to engage one end of said cells at the inner extremity of said matrix and provide a backing for said matrix to thereby permit said matrix to deflect from both ends in response to the application of an impact load thereto to thereby absorb impact energy.
3. A vehicle bumper comprising a resilient one-piece matrix molded from plastic material for absorbing energy of an impact load applied thereto, said matrix having a plurality of generally parallel and longitudinally extending cells disposed adjacent to each other, a number of said cells being formed by a plurality of substantially thin, flat wall means which intersect one another to form polygonal open spaces therebetween which extend uninterrupted between inner and outer extremities of said matrix, a first number of said wall means being laterally spaced from each other and tapering from minimal thickness at opposite ends thereof to a maximum thickness on a parting line in a plane extending laterally of and between the ends of said cell means, a second number of said wall means being angularly disposed with respect to said first number of said wall means and vertically spaced from each other and also tapering from minimal thicknesses at opposite ends thereof to a maximum thickness on said parting line, said cells having deflecting zones extending longitudinally from either side of the parting line to the inner and outer extremities of said matrix, a support for said matrix adapted to engage and support one end of said cells at the inner extremity of said matrix to thereby permit said matrix to deflect from both extremities in response to the application of an impact load thereto to thereby absorb impact energy.
4. A vehicle bumper comprising a resilient one-piece matrix of plastic material for absorbing vehicle impact energy, said matrix having a multiple number of uninterrupted open cells extending longitudinally of said matrix and between opposite extremities thereof, said cells being formed by angularly disposed thin, flat wall means which intersect one another to form polygonal open spaces therebetween, a first number of said wall means being laterally spaced from each other and tapering from a minimal thickness at opposite ends thereof to a maximum thickness in a predetermined plane between the forward and rearward ends of said matrix, a second number of said walls being vertically spaced from each other and disposed at a predetermined angle with respect to the first number of said wall means, said second number of said wall means tapering from a minimal thickness at opposite ends thereof to a maximum thickness at said predetermined plane between said forward and rearward ends of said matrix, a support for said matrix adapted to engage one end of said cells and provide a backing and support for said matrix to thereby permit said matrix to flex from at least two separate deflection zones provided by said cells on opposite sides of a parting line formed by said predetermined plane in response to the application of an impact load thereto.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US65335076A | 1976-01-29 | 1976-01-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1059554A true CA1059554A (en) | 1979-07-31 |
Family
ID=24620493
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA261,414A Expired CA1059554A (en) | 1976-01-29 | 1976-09-17 | Energy absorbing cellular matrix for vehicles with plural working zones |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1059554A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4762352A (en) * | 1985-11-29 | 1988-08-09 | Honda Giken Kogyo Kabushiki Kaisha | Synthetic resin bumper assembly |
| US4773685A (en) * | 1986-01-20 | 1988-09-27 | Stamicarbon B.V. | Bumper |
-
1976
- 1976-09-17 CA CA261,414A patent/CA1059554A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4762352A (en) * | 1985-11-29 | 1988-08-09 | Honda Giken Kogyo Kabushiki Kaisha | Synthetic resin bumper assembly |
| US4773685A (en) * | 1986-01-20 | 1988-09-27 | Stamicarbon B.V. | Bumper |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1045183A (en) | Energy absorbing cellular matrix for vehicles | |
| US3926463A (en) | Shock absorbing buffer assembly | |
| US4671550A (en) | Bumper beam | |
| US6485072B1 (en) | Bumper system for motor vehicles | |
| US4904008A (en) | Molded one-piece bumper | |
| EP2237991B1 (en) | Tray energy absorber and bumper system | |
| CN100488812C (en) | Bumper beam and bumper assembly including a bumper beam | |
| US6371540B1 (en) | Bumper beam for motor vehicles | |
| EP1888378B1 (en) | Bumper assembly with energy absorber | |
| CN101353060B (en) | Energy-absorbing vehicle hood assembly with cushion inner structure | |
| CN101090842A (en) | Bumper system with energy absorber | |
| JPS62128852A (en) | Bumper made of synthetic resin for automobile | |
| JP2008513260A (en) | Bumper assembly including energy absorbing member with vertical translational crush lobe | |
| US20060131931A1 (en) | Energy absorbing vehicle fender | |
| US20060113825A1 (en) | Energy absorbing vehicle fender | |
| CA1059554A (en) | Energy absorbing cellular matrix for vehicles with plural working zones | |
| US20060125289A1 (en) | Energy absorbing vehicle fender | |
| US6857690B2 (en) | Protective structure for vehicles | |
| CN210652995U (en) | Energy absorption box for electric vehicle | |
| KR101313667B1 (en) | Crash box having low weight and improved impact absorbtion ability | |
| US3692345A (en) | Composite bumpers | |
| CN108482491B (en) | Three-section front end structure for flexible leg type collision | |
| JPS60222345A (en) | Instrument panel | |
| JPH0133404Y2 (en) | ||
| CN216734166U (en) | Automobile front anti-collision beam |