EDGE PROTECTOR TRIM STRIP

Abstract: A trim strip for a projecting edge part of an automobile body and the like is designed to require a low installation force and a high removal force. The trim strip includes a generally U-shaped body (22) of polymeric material surrounding a semi-rigid carrier (26). One or more inwardly extending gripper fins (30, 34) is disposed on each of the two arms of the U-shaped body and extends inwardly towards the base of the U. At least one of the gripper fins (34) has a layer of high coefficient of friction material (38) substantially only on the end and is shaped so that during installation of the strip, the high coefficient of friction material retracts to minimize installation resistance. On removal of the trim strip, the high coefficient of friction material is urged into more intimate contact with the flange to maximize resistance to removal.

Description: E5GE PROTECTOR TRIM STRIP This invention relates in general to edge protector trim strips and more particularly to an edge protector trim strip having improved installation and retention characteristics compared to prior art trim strips. An early example of edge protector trim strips may be found in F.J. Lansing U.S. Patent No. 3,198,689. Such trim strips are commonly employed to seal the edges of metal panels or plates of doors, door frames or other projecting" edge parts of the interiors of automobile bodies and the like and strips of the type shown in the Lansing patent as well as improvements thereon have become extremely widely employed for such purposes. A p_rsistenc problem attending the use of such strips has been to provide a strip which requires only a reasonable force to install while at the same time providing great resistance to removal. Trim strips of the type with which this invention is concerned are normally manufactured in indefinite lengths and have a generally U-shaped cross-section, are resiliently deformable and capable of bending and are normally manufactured of rubbery or plastic material strengthened by a metallic or equivalent carrier located inside the rubbery or plastic material. The strips are held in place on the flange by means of grippers or fins extending inwardly from the arms of the U towards the base of the U the grippers or fins being deformable and made of rubber or plastic material. Examples of such prior art trim strips are shown in U.S. Patents Nos. 4,092,813; 4,232,081; 4,188,765; 4,015,814; 3,685,231; 3,545,157 and 3,167,825. These patents show various combinations of hard and soft grippers or fins within a U-shaped profile and various combinations of large and small fins on one side or the other of the interior of such profiles. It has been recognized, specifically in Patent No. 4,092,813, that providing a fin or gripper of a soft material which functions as an antisliding surface improves the retention characteristics of the trim strip. It is claimed in the patent that the ratio of the force needed to apply the trim strip to a flange to the force required to remove it is about 1:2. While the trim strip shown in this " patent was a significant improvement over the art at the time it was made, the current requirements for installation and retention forces and particularly for retention forces exceed those which can be provided by any of the prior art trim strips. It has heretofore been believed that increased retention characteristics could only be achieved by increasing the amount' of anti-sliding material on the grippers or fins of a trim strip, or by increasing the stiffness of the metal carrier within the trim strip or both. For example, where wire carriers are employed, increasing the guage of the wire used to knit said carrier from 0.030" to 0.036" has been proposed. It has been determined that such changes only mini umly increase the retentive capacity of such trim strips, and that they Increase the installation force as well. Additionally, increasing the stiffness of the metal carrier of such trim strips decreases the flexibility of the strip as a whole, and reduces the capability of the strip to conform to sharp radius corners. Still further, increasing the stiffness of the metal -carrier increases the weight of the strip as well as the cost thereof. Accordingly, it is an object of this invention to provide an edge protector trim strip having a significantly improved ratio of installation force to retention force. It is a further object of this invention to provide an edge protector trim strip that is flexible and retains the capability of following contours including sharp bends or corners. It is still another object of this invention to provide an edge protector trim strip that can be manufactured using substantially the same methods and equipment as prior art trim strips. It is another object of this invention to provide a trim strip which resists the leakage of water between the strip and the flange to which it is mounted. Briefly stated and in accordance with a presently preferred embodiment of this invention, an edge protector trim strip having a body of generally U-shaped cross-section is formed of polymeric material such as rubber or plastic and stiffened by a semi-rigid carrier. One or more grippers or fins extends from each of the arms of the U inwardly therefrom towards the base of the U. At least one of said grippers or fins has a layer of high coefficient of friction material substantially only on the end thereof. The fin on which the layer of high coefficient of friction material is located is shaped so that during installation of the strip, only a limited portion of such layer contacts the flange on which the strip is mounted. Preferably, the gripper or fin to which the high coefficient of friction layer is attached is cam-shaped or curved so as to ride on the leading edge of the flange and thereby, to at least partially retract on installation of the trim strip to reduce the area of contact between the high coefficient of friction layer and the flange. The fin is preferably designed to urge the high coefficient of friction material into a larger area of contact with the flange on removal of the trim strip, and increase the pressure between the high coefficient of friction layer and the flange thereby greatly increasing the force required to remove the trim strip from the flange. While the best prior art trim strips have provided ratios of insertion forc " to removal force of one to four, the trim strip of this invention yields ratios as high as one to seven or one to eight or greater. While the novel features of the invention are pointed out with particularity in the appended claims, the invention itself together with further objects and advantages thereof may be " more fully understood by reference to the following detailed* description thereof taken in connection with the accompanying drawing in which: Figure 1 is an sectional view of an edge protector trim strip in accordance with a preferred embodiment of this invention; Figure 2 is a sectional view of the edge protector trim strip of Fig. 1 mounted on a metal flange; and Figure 3 is a sectional view of the edge protector trim strip of Fig. 1 mounted on a metal lange. Referring now to Figure 1, an edge protector trim strip 10 has a generally U-shaped body portion 12 including first and second legs 16 and 18 connected by a base 22. As can be seen from Fig. 1, the strip may have a sealing member 50 attached to or integral with the arm 18 to provide a combined edge protector, trim and sealing strip, which can form a seal with the periphery of a door of the vehicle when the latter is closed. Alternatively, the sealing member 50 may be in the form of a separate member applied to the periphery of the door. Body 12 is preferably formed principally of a resilient plastic or rubbery material such as rubber or polyvinyl chloride or TPR having a durometer in the range of 60-80 as measured on the Shore A hardness scale. Body 12 may be extruded over a semi-rigid " carrier 26 of known construction such as a U-shaped knitted wire carrier or a U-shaped stamped metal carrier, each of conventional design and often times used in edge protector trim strips of this type. In accordance with the present invention, one arm 18 of body 12 has one or more inwardly projecting minor fins extending from the inner surface of the arm 18 towards base 22. Preferably, minor fins 30 are formed of the same plastic or rubbery material as body 12 and may conveniently be formed along with body 12 by extrusion. Preferably, sealing member 50 is softer than body 12 as is well known. Opposite leg 16 of body 12 has a major fin 34 projecting therefrom towards base 22 of body 12. Preferably, major fin 34 is formed from the same plastic or rubbery material as body 12 and minor fins 30 and includes, adjacent to the tip thereof, a layer of high coefficient of friction material 38 which is substantially restricted to the inner end portion of fin 34. Preferably, the high coefficient of friction layer 38 is formed from rubber or other material having both a high coefficient of friction and good -$ - sealing characteristics wi h respect to a flange on which the trim strip of this invention is mounted. In this way, a seal is formed between the trim strip and the flange that prevents water from leaking around the end of the flange. Layer 38 and sealing member 50 may be formed o£ the same material, preferably rubber, thereby reducing the number of materials that are co-extruded to two. Fin 34 is shaped, and layer 38 is located thereon so that when a trim strip is installed on a flange, the leading edge of the trim strip displaces fin 34 and reduces the area of contact be ' tween layer 38 and the side of the flange. Preferably, fin 38 is cam-shaped as shown to permit a relatively large layer or layer of high coefficient of friction material to be used while at the same time limiting the surface area of the layer or layer that contacts the flange during installation to less than the entire surface of such bead, and preferably a minor portion thereof. It will be appreciated that while a curved fin 34 is preferred, a straight fin and preferably a straight tapered fin can accomplish the same function. Preferably, when a straight tapered fin is employed, a smaller layer of high coefficient of friction material is placed on the fin and is located close to the end of the fin. " By utilizing one or more resilient, but not particularly high coefficient or friction, minor fins 30 and a single major fin 34 in combination with a small layer of high coefficient of friction material 38 on the major fin 34, a trim strip is provided with a unique combination of ease of- installation and high retentive force. Additionally, because minor fins 30 do not have a particularly high coefficient of -7- friction, a plurality of such fins may be employed to signi icantly improve the seal between the trim strip and the flange while retaining the desired installation and retention charac eristics. Referring now to Figure 2, the trim strip of Figure 1 is shown as installed o a metal flange 40. As trim strip 10 is forced onto flange 40, minor fins 30 and major fin 34 retract to a slightly bent over position as shown in Figure 2. Preferably, minor fins 30 do not exhibit a particularly high coefficient of friction and do not significantly impede the installation of the trim strip onto flange 40 with the U-shaped hollow center portion of the trim strip receiving the flange. Major fin 34 and high coefficient of friction layer 38 thereon which contacts flange 40 during installation tend to resist the insertion of flange 40. However, because fin 34 is resilient, it is readily pushed back and does not impart a substantial amount of pressure at' the point of contact between layer 38 and flange 40. In this way, insertion of the flange into the trim strip may be accomplished with a force on the order of 15 newtons. As trim strip 10 is pulled from the flange minor fins 30 offer little resistance to removal, but continue to urge flange 40 against a high coefficient of friction layer 3S of raa or fin 34. Bead 38 grips the surface of flange 40 tightly thereby increasing the pressure on fins 30 as more force is exerted on trim strip 10, more and more of the surface of layer 30 comes into contact with the flange. It is important that fins 30, unlike the soft fins used in Patent No. 4,092,813, resist such forces to maintain the increasingly large area of contact between layer 38 and the opposite surface of flange 40. In this way, as can be clearly seen by reference to Figure 2, flange 40 is substantially locked into place and removal forces in excess of 100 newtons are required to pull the trim strip off the flange. It is the use of relatively firm low coefficient of friction minor fins 30 that allows a small layer of high coefficient of friction material to securely lock the trim strip onto flange 40. Because only a small layer of high coefficient of friction material Is necessary, the insertion force required to install the trim strip is significantly reduced from prior art trim strips while, surprisingly, removal force is increased. Although other trim strips have achieved either low insertion force or great resistance to removal, none has achieved the combination thereof in a manner even approaching that achieved by this invention. Eggert Patent No. 4,092,813 employed a plurality of relatively high friction, but soft gripper fins in place of Applicant's relatively hard low friction fins 30 and additionally employed a major fin having substantially the entire inner surface thereof covered with a high coefficient of friction soft material in place of Applicant's fin 34. Unfortunately, the resistance to installation on a flange exhibited by the prior art trim strip was higher than desirable while at the same time the resistance to removal was lower than desirable. This is believed to be due to the large area of contact between the high coefficient of friction material forming the three small fins and the inner surface of the large fin. The high coefficient of friction material on such fins contacts the flange over a significantly wider area than is the case with Applicant's invention. This, coupled with the inability of the soft fins to provide the resistance to removal provided by Applicant's relatively stiff. fins 30 increases the insertion force and decrease the removal force. While the invention has been shown in connection with a presently preferred embodiment thereof, it will be recognized by those skilled in the art that certain modifications and changes may be made thereto without departing from the true spirit and scope of the invention. For example, while three minor fins 30 have been illustrated, it will be understood that the number of such fins is not critical and may be reduced or increased as desired. Further, while only a single major fin 34 is required, an additional major fin may be employed, recognizing that the same will at least slightly increase both the insertion force and the retention force of the trim strip. . Accordingly, it is intended that the •invention includes these and other modifications and changes as fall within the true spirit and scope thereof.

Claims: - 10 - Clai ms : 1. In an edge protector trim strip including a resilient body of substantially U-shaped con iguration surrounding a semirigid carrier and including first and second leg portions joined by a base portion, the improvement comprising: at least one fin extending from the inner surface of each leg generally towards said base portion of said body, the average durometer of each of said fins being substantially equal and said fins having a first coefficient of friction; and a layer of relatively higher coefficient of friction material adjacent only the end of one of said fins. 2. The trim strip of claim 1 wherein said fins comprise the same material as the body portion of said trim strip. 3. The trim strip of claim 2 wherein said layer of relatively high coefficient of friction material comprises a layer of material having a durometer of less than the durometer of said fin. 4. The trim strip of claim 3 comprising three fins extending from said one leg of said body portion and one fin extending from said other leg of said body portion, said layer of relatively high coefficient of friction material disposed adjacent only said one fin. 5. In an edge protector trim strip for mounting on a flange, a locking fin comprising a resilient body portion and a layer of high coefficient of friction material on the end of said body portion, said fin shaped so that on installation of said trim strip onto said flange, the end of said fin carrying said layer is at least partially de-flected by said flange to reduce the area of - 11 - contact between said layer and said flange. 6. The edge protector trim strip of claim 5 wherein said fin is cam-shaped. 7. The trim strip of claim 6 wherein said layer is disposed substantially only on the end of said fin so that on installation, said flange contacts said fin below said layer to deflect said in. 8. A trim strip comprising; a substantially U-shaped resilient body having first and second leg portions and a base portion; a semirigid carrier within said body; a locking fin fixed adjacent an inner surface of one of said leg portions characterized by a shape such that when said strip is installed on a flange, at least the end of said fin is deflected out of engagement with said flange; and a layer of relatively high coefficient of friction material disposed on said end of said fin. 9. The strip of claim 8 wherein said fin comprises a cam-shaped fin. 10. The trim strip of claim 8 wherein said fin comprises a tapered fin and said layer is disposed substantially only at the end of said fin. 11. The trim strip of claim 8 further comprising one or more fins on the inner surface of the other of said legs. 12. The trim strip of claim 8 wherein said body and said fin comprise a first elastomer and said layer comprises a second elastomer of lower durometer than said first elastomer. 13. The trim strip of claim 8 wherein said body and said fin comprise a first elastomer and said layer comprises a second elastomer of higher - 12 - coefficient of friction than said first elsatomer. 14. The trim strip of claim 11 wherein said body and said fin comprise a first elastomer and said layer comprises a second elastomer of higher coefficient of friction than said first elastomer.

Inventors: JACKSON WINTON W JR, RYBA ROBERT M, JACKSON, WINTON, W., JR., RYBA, ROBERT, M.
Applicants: SCHLEGEL CORP, SCHLEGEL CORPORATION
Application year: 1985
Main classification: B60R13
IPC codes: B60J10, B60R13