The present invention relates to multi-directionally swept beams and also roll-forming apparatus and methods for forming multi-directionally swept beams and structural members, such as can be used as bumper reinforcement beams, vehicle frames, and non-linear structural members. The present invention further relates to beams and structural members made by same. The present invention is not limited to only bumper reinforcement beams and/or vehicle frames, nor is it limited to apparatus and methods for forming/constructing only these components.
Roll-forming can be a particularly cost-effective way of producing elongated beams and structural members (channel-shaped and tubular), since roll-forming is capable of mass-producing high volumes with relatively lower cost tooling and longer lasting tooling (as compared to stamping dies, especially when high-strength materials are being formed that will quickly wear out stamping dies). However, roll-forming has limitations, such as a limited ability to form non-linear products.
Several ways are known for forming sweeps and curved elongated structural members. For example, see Sturrus U.S. Pat. No. 5,092,512, Sturrus U.S. Pat. No. 5,454,504, and Lyons Published Application U.S. 2006/0277960 which disclose ways of imparting a sweep(s) into a continuous beam made of high-strength material, where the beam has a strength and shape suitable for use as a bumper reinforcement beam. However, these processes are limited to forming beams swept to form one-directional concave shapes. These processes are not capable of forming a beam with alternating (back-and-forth) sweeps, where the alternative sweeps are in opposite directions away from a roll-formed centerline.
Notably, the difficulties of consistently sweep-forming beams and structural members into non-linear shapes is greatly increased as the size and bending moment of a structural beam increases, such as when the beam has a tubular cross section of greater than 50 mm×50 mm, and/or when the sheet material has a high strength (e.g., greater than about 60 KSI tensile strength up to 220 KSI tensile strength), and/or when the swept curvature is relatively sharp such as defining a radius of less than 1500 mm, and/or when sheet thicknesses are greater than 2 mm, . . . especially for combinations of the above.
In one aspect of the present invention, a roll form apparatus includes a roll former with rolls for forming a sheet of steel material into a structural beam defining a longitudinal line. The apparatus further includes a sweep station in-line with the roll former, where the sweep station includes a sweep-forming device for selectively sweeping the structural beam in a first direction away from the longitudinal line and in a second direction opposite the first direction away from the longitudinal line while continuously operating the roll former.
In another aspect of the present invention, a sweep station is provided for sweeping sections of a beam away from a longitudinal line defined by the beam. The sweep station includes a main frame, and a sweep-forming device including a subframe operably supported on the main frame for movement to a first position to sweep a first section of the beam in a first direction away from the longitudinal line and for movement to a second position to sweep a second section of the beam in a second direction away from the longitudinal line, the second direction being on a side opposite the first direction.
In another aspect of the present invention, a method of roll-forming comprises steps of: roll-forming a sheet of material into a continuous beam defining a longitudinal line; and during the step of roll-forming, sweeping a first section of the continuous beam in a first direction away from the longitudinal line and sweeping a second section of the continuous beam away from the longitudinal line in a second direction different than the first direction.
In a narrower aspect of the present invention, the method includes forming a frame incorporating the beam with first and second oppositely swept sections.
In a narrower aspect of the present invention, the beam forms a bumper reinforcement beam and/or a vehicle frame component.
In a narrower aspect of the present invention, an energy-absorbing bumper-mounting bracket is attached to the beam at an end of the beam.
In a narrower aspect of the present invention, the beam is tubular and has a cross-sectional dimension in a direction of the bend that is at least about 25 mm. Further, the material strength is preferably at least about 60 KSI tensile strength, for providing a high strength-to-weight ratio.
An object of the present invention is to provide a beam, either channel-shaped or tubular, made from steel sheet material (or having similar or greater tensile strength) and with a cross section of substantial size (such as 2 inches or more in a direction of bending), where the beam is swept back-and-forth in opposite directions from a roll-formed centerline during the roll forming process.
An object of the present invention is to provide an apparatus and method capable of sweeping a beam of substantial material strength and cross-sectional beam strength in a back-and-forth pattern including swept sections curved in opposite directions from a roll-formed centerline.
An object of the present invention is to construct a frame using the beam components with back-and-forth sweeps as noted above.
An object of the present invention is to provide internal and/or external stabilizers in a roll-forming apparatus to allow the apparatus to make increasingly sharp sweeps in a beam while maintaining dimensional accuracy and consistency of the beam's cross section.
These and other aspects, objects, and features of the present invention will be understood and appreciated by those skilled in the art upon studying the following specification, claims, and appended drawings.
A roll form apparatus 30 (
An exemplary bumper reinforcement beam 34 (
Notably, the center section 37/38, defines a single plane with ends 35 and 40, but the center section 37/38 is bent to a misaligned position relative to the ends 35 and 40 as part of the roll-forming and sweeping operation. The center section 37/38 can additionally be reformed in a secondary operation to position the center section 37/38 rearward as well as below the aligned ends 35 and 40 (with top and bottom surfaces maintained in a horizontal orientation, when in the vehicle-mounted position.) This allows use of a single cross beam (34) to support a hitch (and trailer tongue) (see hole 34′ for receiving a ball hitch), yet allows proper height and fore-aft position of the hitch relative to the vehicle frame. Further, it allows all of the orthogonal walls of the beam (34) to be optimally oriented in horizontal and vertical positions for supporting weight.
A variety of different frame and structural components can be made using the concepts incorporated into the shape of the beam 34. For example,
More specifically in regard to the roll form apparatus 30 (
The sweep station 32 is attached in-line at an end of the roll former 31, and includes sweeping rolls for selectively sweeping/deforming the continuous beam 33 in either of opposing directions from the longitudinal centerline of the continuous beam 33. A cutoff device 57 receives the bilaterally swept beam 33 and cuts it at selected locations relative to the bends formed in the bilaterally swept beam 33 to achieve beam segments 34 having a desired length, and with the swept sections contained at strategic locations along the beam segments 34. The illustrated bilaterally swept beam segment 34 includes sections 35-40 (
The sweep station 32 (
The subframe 63 is operably supported for double-pivoting-and-translating movement by adjustable support structure that engages bearing structures 80 and 100 on the frame 60 as shown by
In particular, the adjustable support structure (
Two of the spacers 83′ form a wedging-type stop for limiting upstream movement of the plate-like guide-following slide member 85. When both plate-like guide-following slide members 85 and 86 are in their seated upstream position (
Two pair of hydraulic actuators 91 (
As noted above, the adjustable support structure further includes a bottom bearing structure 100 (
As shown by
In the first position of
Testing has shown that the present sweep station 32 can deform the continuous beam 33 to a sweep of 1000 mm radius in either selected direction when forming material having a tensile strength of 190 KSI and a cross sectional tubular beam of about 70 mm×70 mm. Further, sweep station 32 is variably controlled by the controller 77 such that the curvature of the sweep can be made constant for a particular section of the beam 33, or can be made to be constantly changing along a particular section of the beam 33, or can be made into a combination of linear and sweeps. Further, the sweeps can be made such that the beam 34 cut from the continuous beam 33 can be symmetrical and can include aligned end sections (see
As discussed previously, an exemplary vehicle frame 110 (
In particular, the right half of the vehicle frame 110 shown in
The left half of the vehicle frame 110 (
The vehicle frame 110 also includes cross members 125, 126 and 127 that extend between the side frame members 111 and rigidly interconnect same. The cross members 125 and 126 are tubular beams (or can be open channels), and include one or more bi-directional bends to meet their dimensional requirements. End flanges are formed on the cross members to matably engage the respective side frame members and to facilitate welding attachment. Also, if desired, crush initiators and/or energy management devices can be incorporated into the cross members 125 and/or 126 and/or 127.
In some circumstances, it may be desirable to provide increasingly sharply curved sweeps that “challenge” the ability of the above sweep station 32. In such event, auxiliary equipment can be added to the sweep station further enhance its ability to provide a dimensionally accurate and consistent sharply curved sweep. Three basic types of such auxiliary equipment are contemplated, including (1) additional downstream external support attached to a downstream side of the sweep station 32 (e.g., a trailing roller or rollers) that engage the continuous beam 33 (called an “external stabilizer”), (2) an upstream external support (called an upstream bend stabilizer or “bridge support”) engaging the beam 33 immediately ahead of the rollers 64, 65, and/or an (3) an internal stabilizer 142 (illustrated as an “internal mandrel chain” connected together in a snake-like manner) (see
The upstream support (called an upstream bend stabilizer or “bridge support”) (
By supporting the beam 33 immediately adjacent an upstream side of the sweep station 32, a dimensional accuracy of the beam 33 can be greatly increased. The reason is because the beam's walls are stabilized and supported to prevent undesired bending and deformation from “counteractive bending forces.” Counteractive bending forces (as used herein) are reactive forces that cause upstream deformation on the beam 33 in a direction away from the bend direction. These reactive forces are caused by the beam 33 acting like a teeter-totter as it is forced to deform around a bending roller (e.g., roller 64). Specifically, the beam's strength and resultant stresses on the beam 33 cause an upstream portion of the beam 33 (for example, 1 to 5 inches ahead of where the beam 33 touches the bending roller 65) to bend in a direction away from the bending roller (64).
It is contemplated that the upstream external support can be located on a single side of the beam 33, but it is contemplated that upstream external supports will likely be positioned on both sides of the beam 33 so that the beam walls are supported regardless of which direction the beam 33 is being swept. (i.e., The upstream external support would stabilize the walls of the beam 33 regardless of whether the beam 33 is being deformed around roller 64 in a first direction of sweep, or is being deformed around roller 65 in a second (opposite) direction of sweep.)
The internal stabilizer 142 (
The illustrated upstream-most first segment 160 is elongated (such as 3-4 inches) and includes apertures for receiving a pin 153 that connects the chain 151 (and block 160) to a loop on the anchor rod 152. The first segment 160 is held in a stationary position located upstream of the pinch point between the rollers 64 and 65. The second segment 161 is also elongated (such as about 4-6 inches) which assists in it staying aligned with the line direction of the roll forming process. The second segment 161 is also held in a stationary position located upstream of the pinch point between the rollers 64 and 65. The segment 161 is followed by several shorter segments 162 (each about an inch or two long) and an elongated last trailing segment 163 (elongated to about 2-3 inches). The segments 162 form a stacked line of blocks/mandrels extending past the pinch point between the rollers 64 and 65, and the segment 163 is located downstream of the rollers 64 and 65. A length of the segments 160, 161 and 163 helps keep their alignment with the continuous beam 33 being formed. The movement of segments 162 and 163 follow a shape caused by the rollers 64 and 65 as the rollers 64 and 65 are moved to different positions (see
Each segment 161-162 has a through-hole, and segments 160 and 163 have a structure for connection to opposite ends of the links of the chain 151. The chain 151 extends through the segments 161-162 and connects the segments 160-163. Each segment 160-163 is structurally made and interconnected in a way to allow rotation in either direction from side to side. Specifically, each segment 161-163 has a joint formed by a narrowed upstream-facing cylindrically-shaped nose and a mating downstream-facing cylindrical recess, so that they abut to form a rotational bearing surface that allows rotation of the snake-like internal mandrel in either direction. It is contemplated that different chains can be used to secure the internal mandrel components together. The illustrated chain 151 includes flat links 155 and transverse pins 156 that interconnect in a manner similar to a bicycle chain or motorcycle drive chain for engaging a sprocket. The illustrated links 155 are flat and each have a figure “8” shape (see
A modified roll forming apparatus 30A (
The apparatus 30A (
In sweep station 32A, the plate-like extendable slide members 85A and 86A (
A front of the slide members 85A and 86A are secured together by a tie rod 210A. The tie rod 210A is adjustable in length so that as the rollers 64A, 65A are adjusted toward each other to engage the beam 33A, the tie rod 210A can also be adjusted. When the slide member 85A is moved downstream, the tie rod 210A causes the large end 88A of the slide member 85A to rotate along a downstream arcuate path around axis 69A during extension. The formed inner surface 204A is shaped to accommodate this movement of the slide member 85A . . . allowing the inner surface 204A to avoid interference from the spacer 83A′ and/or 83A.
An adjustment mechanism (
It is noted that the “sweep limiter” chain (94) is eliminated in the present sweep station. Instead, a potentiometer or sensor system is attached between a stationary part of the sweep station 32A and the subframe 63A. The potentiometers 215A are connected to the controller 77 for controlling the actuators 91A . . . which in turn control a position of the sub-frame 32A and bending rollers 64A, 65A so that the beam 33A is given a particular desired sweep radii (i.e., longitudinal curvature). The potentiometers 215A also operate to sense when (if) the sweep station is “over-extended” in a downstream direction. Specifically, a potentiometer 215A (
Various modifications are made to various components for handling the high stresses generated in the present sweep station. Also, modifications are made to increase efficiency of operation. For example, the apertures 220A in the side end plates 66A and other plates of the subframe 63A allows an operator to see into the sweep station, allowing better control since one can see what is happening within the sweep station. Also, the anchoring stanchion 200A is designed for optional handling of stress and for handling a great amount of stress without failure or unacceptable deformation.
It is to be understood that variations and modifications can be made on the aforementioned structure without departing from the concepts of the present invention, and further it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise.
This application claims benefit under 35 U.S.C. §119(e) of provisional application Ser. No. 61/043,541, filed Apr. 9, 2008, entitled MULTI-DIRECTIONALLY SWEPT BEAM, ROLL FORMER, AND METHOD, the entire contents of which are incorporated herein in their entirety.
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