IL103233A

IL103233A - Energy absorbing device

Info

Publication number: IL103233A
Application number: IL10323392A
Authority: IL
Original assignee: Sintram Ltd
Priority date: 1992-09-21
Filing date: 1992-09-21
Publication date: 1994-10-07
Also published as: WO1994007051A1; AU5162193A; IL103233A0

Description

AN ENERGY ABSORBING DEVICE SI TRAM C: 15643 15643sin.trm 1-9032 20sep92 FIELD OF THE INVENTION The present invention relates to a device for absorbing impact energy.

BACKGROUND OF THE INVENTION Energy absorption devices are known in the art. U.S. Patent 5,074,391, to the present applicant, describes one which utilizes a body, formed of a billet of ductile material and a crushable sleeve, which is forced against a die during impact.

PCT patent application PCT/US/90/06421, also to the present applicant, describes an improved energy absorption device which utilizes a cage inside of which is a die against which the body of crushable sleeve and/or billet of ductile material is forced. During impact, the crushable sleeve is crushed against the outer side of the die and is forced between the bars of the cage while the billet is forced through the die and deformed thereby.

It has been discovered that after impact, the body is not easily removed from the cage and die apparatus. To do so requires a large expenditure of force.

The disclosures of U.S. Patent 5,074,391 and PCT/US/90/06421 are incorporated herein by reference.

SUMMARY OF THE INVENTION It is an object of the present invention to provide improved energy absorption devices.

It is a further object of the present invention to provide an energy absorption device which is relatively easy to disassemble after impact.

There is therefore provided, in accordance with a first preferred embodiment of the present invention, an energy absorbing device including a) a deformable and crushable body arranged along a longitudinal axis operative to receive an axial impact force at a first end thereof along the longitudinal axis and to transmit the axial impact force axially therethrough to a second end thereof and b) disassemblable energy converting apparatus arranged adjacent the second end of the body for deforming and crushing the body upon receipt of the axial impact force thereby to convert energy from the axial impact force to mechanical energy.

Additionally, in accordance with the first preferred embodiment of the present invention, the disassemblable energy converting apparatus includes a) a base having a plurality of bars, b) a ring mountable on the base and having a plurality of spacers equal in number to the plurality of bars, c) a top attachable to the base and d) a die mountable within the base.

Moreover, in accordance with the first preferred embodiment of the present invention, the body is formed of a crushable sleeve. Alternatively, the body is formed of a ductile billet surrounded by a crushable sleeve.

There is also provided, in accordance with a second preferred embodiment of the present invention, an energy absorbing device including a) a body formed of at least two crushable sleeves arranged along a longitudinal axis operative to receive an axial impact force at a first end thereof along the longitudinal axis and to transmit the axial impact force axially therethrough to a second end thereof and b) energy converting apparatus arranged adjacent the second end of the body for deforming 103233/2 and crushing the body upon receipt of the axial impact force thereby to convert energy from the axial impact force to mechanical energy.

Additionally, in accordance with the second preferred embodiment of the present invention, the energy converting apparatus includes a) an outer cage having a plurality of first bars, b) at least one inner cage each having, at one end thereof, a plurality pf second bars equal in number to the plurality of first bars and having an inclined surface at a second end thereof and c) a die. The die is mountable within the innermost one of the at least one inner cage, and the at least one inner cage is mountable witjiin the outer cage.

Moreover, in accordance with the second preferred embodiment of the present invention, the body can include a ductile billet.

Finally, in accordance with the preferred embodiments of the present invention, the axial impact force is a tensile force or a compressive force.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be understood and appreciated more fully from the following detailed description taken in conjunction with the drawings in which: Fig. 1A is a schematic cut section of an energy absorption device which can be disassembled, constructed and operative in accordance with a first preferred embodiment of the present invention; · Fig. IB is an isometric exploded illustration of elements of the device of Fig. 1A; Fig. 2 is a schematic cut section of the device of Fig. 1 after impact; Fig. 3 is an exploded cut section view of the device of Fig. 1 during disassembly; Fig. 4 is a schematic cut section view of an improved energy absorption device utilizing more than one crushable sleeve, constructed and operative in accordance with a second preferred embodiment of the present invention; and Fig. 5 is an exploded illustration of the elements of the crushing end of the device of Fig. 4. it 103233/3 DETAILED DESCRIPTION OF PRESENT INVENTION Reference is now made to Figs. 1 - 3 which illustrate an energy absorption device which can be disassembled, constructed and operative in accordance with the first embodiment of the present invention. Figs. 1A, IB and 2 illustrate the device before and after impact, respectively, and Fig. 3 illustrates the disassembly of the device after impact.

The energy absorption device typically comprises a body having an impact surface 12 at one end and an energy converting apparatus 14, which can be disassembled, at the other end. The body can be formed of a crushable sleeve 10, as shown in Fig. 1A, or it can be- formed of a ductile billet surrounded by a crushable sleeve, as described in PCT application PCT/US/90/06421.

Energy converting apparatus 14 typically comprises a cage 16 and a die 18 which sits therein. Energy converting apparatus 14 is operative to convert the impact force to mechanical energy by crushing, deforming and/or extruding the body in a manner similar to that described in PCT application PCT/US/90/06421. For the example of Figs. 1 - 3 wherein the body includes only a crushable sleeve 10, when impact surface 12 receives an impact, the crushable sleeve 10 impacts the die 18 which directs the sleeve 10 towards the cage 16. The impact forces the crushable sleeve 10 against bars 20 (Fig. 2) of cage 16 which causes the sleeve 10 to break into strips 19 (Fig. 2) which exit the apparatus 14 between the bars 20.

In accordance with one embodiment of the present invention, cage 16 is comprised of a base 22 having the bars 20 formed therein in a fork-like manner and having threads 24 formed on an outside thereof, a ring 26, having spacers 27 formed therein, which sits on the bars 20 to maintain the spacing therebetween, and a top 28 in the form of a nut which screws onto base 22 above ring 26. Top 28 serves both to hold the cage 16 together and to support body 10.

Fig. IB presents an isometric, exploded view of the cooperation of base 22 and ring 20. 103233/2 It will be appreciated that a lower portion of base 22 can be formed in a ring 29 to which the bars 20 are attached. The ring 29 enables the ductile billet, if it forms part of the body, to extrude therethrough.

The device of Fig. 1A is assembled by placing the ring 26 on the base 22 and thereafter, screwing top 28 onto base 22. The die 18 is then placed within cage 16 and the crushable sleeve 10, to which is attached impact surface 12, is placed around die 18 within cage 16. If the body is formed of a ductile billet surrounded by a crushable sleeve, the body is placed on the die 18, within cage 16.

The effects of impact are shown in Fig. 2. The strips 19 of the crushable sleeve 10 extend through the spaces between bars 20, making apparatus 14 and the sleeve 10 a single unit, which, in the prior art described in the Background of the Invention, could not be disassembled. However, in accordance with the present invention and as shown in Fig. 3, the device can be disassembled and apparatus 14 reused.

After impact, the impact surface 12 is removed from the crushable sleeve 10. The top 28, which slides easily around a portion 30 of the crushable sleeve 10 which has not yet been crushed, is unscrewed from the base 22 and is slid towards the non-crushed end of the crushable sleeve 10.

The base 22, which is now free to move, is pulled away from the strips 19 in a direction noted by arrow 32. The die 18, which, in the embodiment shown in Figs. 1A and 2, is no longer constrained, is then removed from within the crushable sleeve 10, in the direction noted by an arrow 34. For the embodiment with the ductile billet, the impact causes the billet to be extruded through die 18. Thus, in order to release the die 18, the billet must be cut and drilled out of die 18.

It will be appreciated that because the base 22 and the top 28 are separatable, after impact the crushed sleeve 10 can be removed from the energy converting apparatus 14.

It is noted that the method of separation can be produced by any suitable means, where threading is shown herein as one example. Other means of separation include a snap-fit device, locking pins, etc.

Reference is now made to Figs. 4 and 5 which illustrate an energy absorption device utilizing more than one crushable sleeve .

The device typically comprises a body formed of at least two crushable sleeves 40 and 42 , an impact surface 44 , and an energy converting apparatus 5 · As in the previous device, the body can also include a billet of ductile material.

The apparatus 45 typically comprises one outer cage 50 , a plurality of inner cages 2 , where only one inner cage 52 is shown in Figs. 4 and 5 . and a die 5^ similar to but typically smaller than die 18 described hereinabove.

It will be appreciated that inner sleeve 42 has an outer diameter smaller than the inner diameter of outer sleeve 40 . It will further be appreciated that, in order to firmly hold both sleeves 40 and 42 , impact surface 44 includes a protrusion 46 locatable within inner sleeve 42 .

Outer cage 50 is a single element similar to cage 16 in the assembled state. As in cage 16 , it comprises a plurality of bars 60 between which the outer sleeve 40 can be pushed. The bottom of outer cage 50 , similar to cage 16 , is a ring 56 , integrally formed with the bars 60 , through which a ductile billet can be extruded.

Inner cage 52 comprises upper and lower portions. In the lower portion, it comprises a plurality of bars, labeled 62 , between which the inner sleeve 42 can be pushed. The bars 62 are integrally formed with a ring 63 and are typically thinner than bars 60 . The upper portion is shaped like die , having an inclined outer surface 64 operative to deflect the outer sleeve 40 between bars 60 of outer cage 0 .

Die 54 is hollow and has an inclined surface 66 operative to deflect the inner sleeve 42 between bars 62 of inner cage 52 . If the ductile billet is included in the body, the inner diameter of die 5 is reduced, thereby to cause extrusion of the billet as it passes therethrough.

Typically, the bars 62 are aligned with bars 60 such that the spaces between the bars are aligned together to enable the crushed inner sleeve 42 to exit the cages 50 and 52 after it has been crushed by its corresponding cage 52. Arrows 70 and 72 indicate the flow of the crushed material.

Alternatively, the bars 62 of the inner cages 52 can be misaligned with the bars 60. This increases the amount of impact force the device can absorb since, in this alternative embodiment, the inner sleeve 42 is crushed first by the inner cage 52 and afterwards by the outer cage 50.

It will be appreciated that the device of Figs. 4 and 5 is operative to absorb high impact energy levels due to an extensive contact area providing extensive friction and thereafter crushing.

If desired, the device shown in Figs. 4 and 5 can be designed to be disassembled as shown with respect to Figs. 1 - 3.

It will be appreciated that the devices shown herein are shown receiving a compressive axial impact force. The devices can also operate upon receiving a tensile impact force provided by pulling a tensile element, such as rod or wire, which extends through the device as shown in detail in the PCT application PCT/US/90/06421.

It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather the scope of the present invention is defined only by the claims which follow:

Claims

1. An energy absorbing device comprising: a deformable and crushable body arranged along a longitudinal axis operative to receive an axial impact force at a first end thereof along said longitudinal axis and to transmit said axial impact force axially therethrough to a second end . thereof ; and ^ disassemblable energy converting means arranged adjacent said second end of said body for deforming and crushing said body upon receipt of said axial impact force thereby to convert energy from said axial impact force to mechanical energy.

2. An energy absorbing device according to claim 1 and wherein said disassemblable energy converting means comprises: a base having a plurality of bars; a ring mountable on said base and having a plurality of spacers equal in number to said plurality of bars; a top attachable to said base; and a die mountable within said base.

3. · An energy absorbing device according to any of the previous claims and wherein said body is formed of a crushable sleeve .

4. An energy absorbing device according to either of claims 1 or 2 and wherein said body is formed of a ductile billet surrounded by a crushable sleeve.

5.. An energy absorbing device according to any of the previous claims and wherein said axial impact force is one of the following group: a tensile force, a compressive force. 103233/2

6. An energy absorbing device comprising: a body formed of at least two crushable sleeves arranged along a longitudinal axis operative to receive an axial impact force at a first end thereof along said longitudinal axis and to transmit said axial impact force axially therethrough to a second end thereof; and energy converting means arranged adjacent said second end of said body for deforming and crushing said body upon receipt of said axial impact force thereby to convert energy from said axial impact force to mechanical energy.

7. An energy absorbing device according to claim 6 and wherein said energy converting means comprises: an outer cage having a plurality of first bars; at least one inner cage each having, at one end thereof, a plurality of second bars equal in number to said plurality of first bars and having an inclined surface at a second end thereof; and a die, wherein said die is mountable within said an innermost one of said at least one inner cage, and said at least one inner cage is mountable within said outer cage.

8. An energy absorbing device according to either of claims 6 or 7 and wherein said body additionally includes a ductile billet.

9. An energy absorbing device according to any of claims 6 8 and wherein said axial impact force is one of the following group: a tensile force, a compressive force. or the Applicant, C:15643 1-9032