Title:
ELASTICALLY FLEXIBLE FASTENER
United States Patent 3806998
Abstract:
An elastically flexible fastener is provided with separable fastening structure carrying flanges having respective shoulder ribs which normally project to a spacing greater than the spacing between inside surfaces of slider walls and deflectable toward one another to be received between the slider walls and in retaining engagement with slider shoulder structures. Assembly of the slider with the fastener is adapted to be effected by snapping the slider into position by relative transverse assembly movement wherein the slider shoulder structures deflect the fastener shoulder ribs inwardly until the slider shoulder structures have cleared the ribs, whereupon the ribs snap resiliently into engagement with the slider shoulder structures.
US Patent References:
Slide fastener
Roehrl - January 1952 - 2581604
Slide fasteners
Hawley - January 1963 - 3074137
Slide fastener
Zimmerman - July 1966 - 3259951
Slide fastener of the extruded type
Koutnik - November 1953 - 2658250
EXPANSIBLE CARRYING CASE
Dyke - May 1969 - 3443671
Slide fastener
Roehrl - January 1952 - 2581604
Slide fasteners
Hawley - January 1963 - 3074137
Slide fastener
Zimmerman - July 1966 - 3259951
Slide fastener of the extruded type
Koutnik - November 1953 - 2658250
EXPANSIBLE CARRYING CASE
Dyke - May 1969 - 3443671
Application Number:
05/150329
Publication Date:
04/30/1974
Filing Date:
06/07/1971
View Patent Images:
Export Citation:
Assignee:
Minigrip, Inc. (Orangeburg, NY)
Primary Class:
Other Classes:
24/427
International Classes:
A44B19/16; B65D33/25; A44B19/10; A44B19/10
Field of Search:
24/21C
US Patent References:
| 3634913 | HINGED FLEXIBLE STRIP CLOSURE | January 1972 | Ausnit |
Primary Examiner:
Gelak, Bernard A.
Claims:
I claim
1. A flexible fastener of the kind having separably interlocking complementary profiled fastening structure adjacent to free edges of flange portions, and a fastener closing and opening slider of generally U-shape straddling said free edges and having side walls along said flange portions each provided with an inwardly projecting slider flange the improvement comprising
2. A flexible fastener of the kind having separably interlocking complementary profiled fastening structure adjacent to free edges of flange portions, and a fastener closing and opening slider of generally U-shape straddling said free edges and having side walls along said flange portions each provided with an inwardly projecting slider flange, the improvement comprising
3. A fastener according to claim 2, in which said shoulders normally extend relatively divergently to the associated flange portions and are moved into alignment with said free flange edges but facing in the opposite direction when in engagement with said shoulder structures.
4. A flexible fastener of the kind having separably interlocking complementary profiled fastening structures adjacent to free edges of flange portions from which the fastening structures project toward one another, and a slider of generally U-shape assembled with the fastener and having side walls each provided with an inwardly projecting shoulder flange on the free marginal portion of the side wall, comprising:
5. A flexible fastener of the kind having separably interlocking complementary profiled faening structure and a fastener closing and opening slider of generally U-shape having a back plate and spaced side walls each provided with a single inwardly projecting slider flange, and wherein:
6. A flexible fastener according to claim 5, in which said ribs are thicker than the inwardly extending length of said slider shoulder flanges so that the inner edges of said shoulder flanges will remain spaced from the adjacent outer sides of said lower flange portion sections.
7. A flexible fastener according to claim 5, wherein the inwardly deflected lower flange sections engage with the fastening structure and thpreby assist in maintaining said ribs in retaining engagement with said slider flange shoulder surfaces.
8. A flexible fastener according to claim 5, wherein said ribs are partially separated from said lower flange sections so that said lower flange sections can be freely flexed away from the ribs at the separations without tending to displace the ribs from said slider flange shoulder surfaces.
9. A flexible fastener according to claim 5, wherein said rib surfaces provide said cam faces.
10. A flexible fastener according to claim 5, wherein said slider flange lower surfaces provide said cam faces.
11. A flexible fastener according to claim 5, wherein said cam faces are provided by both said rib surfaces and said slider flange lower surfaces.
12. A flexible fastener according to claim 5, wherein said ribs have shoulder surfaces which are complementary to and in the retaining engagement with said slider flange surfaces engage flat against the slider flange shoulder surfaces.
1. A flexible fastener of the kind having separably interlocking complementary profiled fastening structure adjacent to free edges of flange portions, and a fastener closing and opening slider of generally U-shape straddling said free edges and having side walls along said flange portions each provided with an inwardly projecting slider flange the improvement comprising
2. A flexible fastener of the kind having separably interlocking complementary profiled fastening structure adjacent to free edges of flange portions, and a fastener closing and opening slider of generally U-shape straddling said free edges and having side walls along said flange portions each provided with an inwardly projecting slider flange, the improvement comprising
3. A fastener according to claim 2, in which said shoulders normally extend relatively divergently to the associated flange portions and are moved into alignment with said free flange edges but facing in the opposite direction when in engagement with said shoulder structures.
4. A flexible fastener of the kind having separably interlocking complementary profiled fastening structures adjacent to free edges of flange portions from which the fastening structures project toward one another, and a slider of generally U-shape assembled with the fastener and having side walls each provided with an inwardly projecting shoulder flange on the free marginal portion of the side wall, comprising:
5. A flexible fastener of the kind having separably interlocking complementary profiled faening structure and a fastener closing and opening slider of generally U-shape having a back plate and spaced side walls each provided with a single inwardly projecting slider flange, and wherein:
6. A flexible fastener according to claim 5, in which said ribs are thicker than the inwardly extending length of said slider shoulder flanges so that the inner edges of said shoulder flanges will remain spaced from the adjacent outer sides of said lower flange portion sections.
7. A flexible fastener according to claim 5, wherein the inwardly deflected lower flange sections engage with the fastening structure and thpreby assist in maintaining said ribs in retaining engagement with said slider flange shoulder surfaces.
8. A flexible fastener according to claim 5, wherein said ribs are partially separated from said lower flange sections so that said lower flange sections can be freely flexed away from the ribs at the separations without tending to displace the ribs from said slider flange shoulder surfaces.
9. A flexible fastener according to claim 5, wherein said rib surfaces provide said cam faces.
10. A flexible fastener according to claim 5, wherein said slider flange lower surfaces provide said cam faces.
11. A flexible fastener according to claim 5, wherein said cam faces are provided by both said rib surfaces and said slider flange lower surfaces.
12. A flexible fastener according to claim 5, wherein said ribs have shoulder surfaces which are complementary to and in the retaining engagement with said slider flange surfaces engage flat against the slider flange shoulder surfaces.
Description:
This invention relates to elastically flexible fasteners and method of assembling sliders therewith and is more particularly concerned with an arrangement in which the slider is adapted to be assembled with the fastener by a relative transverse maneuver as compared to conventional endwise assembly.
In my U.S. Pat. No. 3,426,396, I have disclosed a slider which is adapted to be assembled with a fastener by relative transverse assembly maneuver, but wherein the slider has flexible side walls to enable clearance of inwardly projecting shoulders along free edges of the slider walls to clear past the body of the fastener into engagement with generally undercut shoulders on the fastener strips and wherein such shoulders are nroamlly conformed to seat on the shoulder structures or noses on the slider walls. Such an arrangement is excellent where the fastener strips are of the multi-interlocking rib and groove type in which the fastener strips assemble together into a substantially solid mass. In such an arrangement after the slider has been assembled with the fastener excellent retention of the slider against displacement from the fastener by forces acting in a transverse separating direction is attained.
However, there are types of elastically flexible fasteners in which there is not the relatively solid body backing, so that after the slider has been mounted on the fastener, there may be a tendency for the slider to separate or come off of the track due to undue flexibility in the area of the shoulder means on the fastener which thus can yield inwardly and slip off of the shoulder or nose structure on the slider walls. It is to the alleviation and solving of this problem that the present invention is particularly directed.
An important object of the present invention is to provide a new and improved elastically flexible fastener expecially equipped for efficient assembly with a slider assembled therewith by a relative transverse maneuver.
Another object of the invention is to provide a separable elastically flexible fastener having new and improved means for retaining cooperation with a slider.
A further object of the invention is to provide a new and improved separable elastically flexible fastener having novel shoulder means thereon for secure interengagement with shoulders on a slider.
Still another object of the invention is to provide a new and improved method of assembling a separable elastically flexible fastener and a slider.
Other objects, features and advantages of the invention will be readily apparent from the following description of a preferred embodiment thereof, taken in conjunction with the accompanying drawing, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts embodied in the disclosure, and in which:
FIG. 1 is a transverse sectional view through a separable elastically flexible fastener embodying features of the invention;
FIG. 2 is a similar view of the fastener illustrating the method of assembling a slider therewith; and
FIG. 3 is a similar sectional view of the fastener showing the slider fully assembled therewith.
By way of example, a separable elastically flexible fastener of the type generally represented by the disclosure in U.S. Pat. No. 3,347,298 has been depicted in the drawing and includes (FIG. 1) a rib element part 5 separably receivable in a groove element part 7. These parts are integrally carried respectively on inner faces of and between aligned lower and upper sections of spaced generally parallel flange portions 8 and 9, which are of generally the same thickness. While the flange portions 8 and 9 may be fastener strips adapted to be secured in a suitable manner to flexible walls of a reclosable container, these flanges may be the actual integral marginal portions of such walls. In any event, the separably interlocking complementary profiled fastening structure and the flange portions 8 and are adapted to be integrally extruded from suitable synthetic plastic material providing an elastically, resiliently flexible construction.
For separable interlocking of the rib element 5 with the groove element 7, the rib element is of generally arrow-shape in transverse cross section including a head 10 comprising interlock shoulder hook portions 11 and 12 generally convergently related to provide a cam ridge 13 generally aligned with a stem flange 14 by which the head is connected in spaced relation with respect to the supporting flange portion 8. At their surfaces nearest the connecting stem flange 14, the shoulder portions 11 and 12 define reentrant angles therewith providing interlock hooks engageable with interlock hook flanges 15 and 17 respectively of the groove element 7. Said hook flanges generally converge toward one another and are spread open to receive the head 10 therebetween when said head is pressed into said groove element 7 until the head is fully received in a groove 18 of said groove element 7 generally complementary to the head and within which the head is interlocked by interengagement of the head shoulder hook portions 11 and 12 and the groove hook flanges 15 and 17. Trhough this arrangement, as indicated, the head and groove elements 5 and 7 are adapted to be interlockingly engaged by being pressed together and to be separated when forcably pulled apart, as by means of a generally U-shaped slider 19 (FIGS. 2 and 3).
By preference, the slider 19 is of the kind described din my U.S. Pat. No. 3,426,396, including a flat back plate 20 adapted to run along free edges 21 on the upper ends of the sections of the flange portions 8 and 9 as shown in the drawing. Integrally formed with the back plate 20 and extending in the same direction (downwardly as shown) therefrom are respective coextensive side walls 22 with an intermediate spreader finger 23 extending in the same direction as the side walls at one end of the slider. It will be appreciated, of course, that the side walls 22 are in the form of panels which are laterally divergent from a narrower end of the slider where the flange portions 8 and 9 are in the nearest approach to one another with the profiled interlocking complementary fastening structure fully interengaged, to a maximum width at the opposite end of the slider where the separating finger 23 is located, and the fastening structure rib and groove elements separated thereby. Thus, a movement of the slider 19 along the elastically flexible fastener in one direction causes the fastener to be closed and movement of the slider along the fastener in the opposite direction causes the fastener to be opened.
In order to retain the slider 19 against transverse displacement from the fastener, that is, against displacement away from the edges 21, the slider walls 22 are each provided with an inwardly projecting shoudler structure 24 flange adapted to engage respective shoulder ribs 25 and 27 on respectively outer sides of the lower sections of the flange portions 8 and 9. In a desirable arrangement, the shoulder flanges 24 are inwardly projecting nose flange formations on the terminal or free end portions of the side walls 22 having respective substantially flat shoulder surfaces 28 which extend generally perpendicularly inwardly from the inner surfaces of the side walls 22 and face toward and are parallel with the inner surface of the body plate 20 and against which generally complementary confronting shoulder surfaces 29 on the shoulder ribs 25 and 27 are engaged in the assembly. Although the shoulder flanges 24 may be provided at either end of the slider 19, a preferred location is at the narrow end where maximum assurance against unintentional pulling of the slider away from the fastener is had because the fastener is fully closed and closely confined by the slider walls 22. This is also desirable where the fastener does not have additional nose flanges located on the separating finger that engage under the fastener parts 5 and 7 at the wider end of the slider.
Substantial improvement in retention of the slider 19 on the fastener is attained by having the shoulder ribs 25 and 27 constructed and arranged to be biased firmly into the reentrant angle defined by the respective shoulder surface 28 and the adjacent inner wall surface of the slider. To this end, the ribs 25 and 27, when not in engagement with the slider, normally project to a spacing which is greater than the spacing between the inside surfaces of the slider walls 22 at least adjacent to the shoulder flanges 24. When the slider is transversely moved over the fastener, the ribs are compressively deflected inwardly toward one another to be finally received in outwardly thrusting relation between the slider walls and in retaining engagement with the slider shoulder structures.
The ribs are so designed that their outward thrust, when engaged by the slider walls, is not great enough to impair the movement of the slider along the fastener. The desirable construction of the shoulder ribs 25 and 27, for this purpose, is as shown in FIG. 1, wherein said ribs are progressively slanted from their fastener strip flange portions to their respective shoulder surfaces 29, so that in each instance said surface is normally at an angle calculated to engage firmly and uniformly with the confronting slider shoulder surface 28 when the angle A is flattened out to become substantially parallel with the engaging surface of the associated slider side wall 22, as best seen in FIG. 3. Advantageously, the progressive thickening of the ribs 25 and 27 toward the shoulders 29, and the consequent progressive resilient stiffening given to the shoulders increases up to the required limit the outward thrust pressure under compression in the full assembly, as the mass of material in the shoulders tends to spring back toward normal.
A further advantage of having the shoulder ribs 25 and 27 slanted along the angles A, generally away from the edges 21 is that in applying the slider 19 to the fastener by transverse assembly, the shoulder flanges 24 can without undue resistance press the ribs 25 and 27 inwardly toward one another, as shown in FIG. 2 until the shoulder surfaces 28 have cleared and receive the rib shoulder surfaces 29. To facilitate this action, the surfaces of the shoulder flanges 24 which face in the opposite downward direction relative to the shoulder surfaces 28 are desirably formed to provide lead-in respective slanting cam surfaces 30 which may be rounded as shown. At the ends where the slider side walls 22 have their greatest resiliency, passage of the shoulder structures 24 past the shoulder ribs 25 and 27 is further eased by expansible yielding of this part of the slider walls in response to resistance to pressing of the shoulder ribs inwardly beyond the respective normal planes of the inner surfaces of the slider side walls. Additional means to ease the assembly interengagement is afforded by respective relief slots 31 extending into the rib shoulders 29 aligned with the normal adjacent surface of the respective flange portion 8 or 9. These longitudinal slots 31 are also advantageous during the extrusion molding of the strips to avoid pulling-in deformation of the rib structure due to shrinkage in the setting or curing of the material.
Another feature in avoiding undue resistance to movement of the slider 19 into assembly with the fastener, comprises having the shoulder rib structures 25 and 27 located on the lower sections of the flange portions 8 and 9 below the complementary profiled fastening structure parts so as to permit relative inward displacement of the lower sections of the flange portions 8 and 9 in the rib areas thereof under and toward the fastening structure parts with some clearance. For example, as indicated in FIG. 1, the clearance afforded for this purpose is represented by the angular lines B. In the normal, undefomed condition of the fastener strip flange portions 8 and 9, the angles which are represented by the lines B and extending from the same point on the outer surfaces of the flange portions 8 and 9 as the angles A, are greater than the angles A, considered with respect to the flange portion outer surfaces, so that as the rib areas of the flange portions are deflected inwardly toward one another generally about axes at the convergence of the angles A and B there will be minimum pressure against the fastening structure profiles during assembly, and until the shoulder ribs have snapped into their interlocking relation with the slider on the fastener, the rib areas of the flange portions 8 and 9 while remaining inwardly deflected will remain free from pressing against the adjacent profiled fastening structure, thus avoiding excess pressure against the slider walls and enabling easy normal functioning of the slider along the length of the fastener. This relationship is enhanced by having the shoulder ribs 25 and 27 respectively of less thickness than clearance spacing between the fastening structure 5, 7 and the inner sides of those lower sections of the flange portions 8 and 9 carrying the shoulder ribs.
Although the slider 19 may be molded from a semi-hard plastic, wherein the side walls 22 are stiffly resiliently flexible at least sufficient to enable spreading apart of the terminal portions of the side walls when the shoulder structures 24 are moved transversely in engagement with the flange portions 8 and 9 past the profiled engaged fastening structure and the ribs 25 and 27, it may be desirable to form the slider 19 from metal as a die casting or molding, or to mold the same from a hard synthetic plastic material such as one of the thermo-setting materials. Where the profiled fastening structure of the fastener is of the type particularly selected for illustrative purposes herein, there is enough yieldability in the connecting web flange 14 and adjacent portions of the fastening structure to enable sufficient elastic deformation while moving the slider shoulder flanges 24 past the fastening structure along the flange portions 8 and 9 for transverse relative assembly movement, even though the shoulder flanges 24 do not yield during the assembly action.
After full assembly of the slider 19 with the fastener has been effected, not only does the resilience of the mass of the shoulder ribs 25 and 27 and the contiguous area of the flange portions 8 and 9 function to maintain a firm interlocked relation to the shoulder flanges 24 of the slider, but the adjacency of the inner surfaces of the flange portions 8 and 9 to the adjacent portion of the groove element 7 also serves to impede back-off of the shoulder ribs, because to escape the shoulder flanges 24, the deflection of the flange portions 8 and 9 must be to the extent of causing compression of the adjacent portion of the hook element 7 as shown in FIG. 2, thus adding the resistance to deformation of that portion of the element 7 to the resistance to deflectional deformation of the flange portions 8 and 9 and the ribs 25 and 27. In addition, by reason of the partial separation of the ribs 25 and 27 by the slots 31, even though compressively closed in the assembled relationship of the parts, the shoulder ribs can remain in their interlocking relation to the slider shoulder flanges 24 while permitting free deflectional yielding of the flange lower sections of the portions 8 and 9 below the ribs to a substantial extent as indicated in dash outline, for example, in FIG. 3 without affecting the shoulder ribs. Pulling forces on the flange portions 8 and 9 are also more effectively resisted because of the separation effected by the slots 31 because the shouldering portions of the ribs by compressing against the shoulder flanges 24 develop increasing resistance to release from the shoulder portions as the pulling force increases.
An additional advantage of ribs 25 and 27, is, that if properly designed, when they are in assembled relationship with the slider, they keep the lower part of the flanges 8 and 9 away from slider shoulder structure inner edge tips 32 and 33, which have a tendency to cut the flanges when moved back and forth in normal use. This can be accomplished by having the ribs thicker than the width of the shoulder structures. As shown, the lower slanting surfaces 30 of the slider flanges 24 extend generally outwardly from the respective inner edges 32 and 33.
It will be understood that variations and modifications may be effected without departing from the spirit and scope of the novel concepts of this invention.
In my U.S. Pat. No. 3,426,396, I have disclosed a slider which is adapted to be assembled with a fastener by relative transverse assembly maneuver, but wherein the slider has flexible side walls to enable clearance of inwardly projecting shoulders along free edges of the slider walls to clear past the body of the fastener into engagement with generally undercut shoulders on the fastener strips and wherein such shoulders are nroamlly conformed to seat on the shoulder structures or noses on the slider walls. Such an arrangement is excellent where the fastener strips are of the multi-interlocking rib and groove type in which the fastener strips assemble together into a substantially solid mass. In such an arrangement after the slider has been assembled with the fastener excellent retention of the slider against displacement from the fastener by forces acting in a transverse separating direction is attained.
However, there are types of elastically flexible fasteners in which there is not the relatively solid body backing, so that after the slider has been mounted on the fastener, there may be a tendency for the slider to separate or come off of the track due to undue flexibility in the area of the shoulder means on the fastener which thus can yield inwardly and slip off of the shoulder or nose structure on the slider walls. It is to the alleviation and solving of this problem that the present invention is particularly directed.
An important object of the present invention is to provide a new and improved elastically flexible fastener expecially equipped for efficient assembly with a slider assembled therewith by a relative transverse maneuver.
Another object of the invention is to provide a separable elastically flexible fastener having new and improved means for retaining cooperation with a slider.
A further object of the invention is to provide a new and improved separable elastically flexible fastener having novel shoulder means thereon for secure interengagement with shoulders on a slider.
Still another object of the invention is to provide a new and improved method of assembling a separable elastically flexible fastener and a slider.
Other objects, features and advantages of the invention will be readily apparent from the following description of a preferred embodiment thereof, taken in conjunction with the accompanying drawing, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts embodied in the disclosure, and in which:
FIG. 1 is a transverse sectional view through a separable elastically flexible fastener embodying features of the invention;
FIG. 2 is a similar view of the fastener illustrating the method of assembling a slider therewith; and
FIG. 3 is a similar sectional view of the fastener showing the slider fully assembled therewith.
By way of example, a separable elastically flexible fastener of the type generally represented by the disclosure in U.S. Pat. No. 3,347,298 has been depicted in the drawing and includes (FIG. 1) a rib element part 5 separably receivable in a groove element part 7. These parts are integrally carried respectively on inner faces of and between aligned lower and upper sections of spaced generally parallel flange portions 8 and 9, which are of generally the same thickness. While the flange portions 8 and 9 may be fastener strips adapted to be secured in a suitable manner to flexible walls of a reclosable container, these flanges may be the actual integral marginal portions of such walls. In any event, the separably interlocking complementary profiled fastening structure and the flange portions 8 and are adapted to be integrally extruded from suitable synthetic plastic material providing an elastically, resiliently flexible construction.
For separable interlocking of the rib element 5 with the groove element 7, the rib element is of generally arrow-shape in transverse cross section including a head 10 comprising interlock shoulder hook portions 11 and 12 generally convergently related to provide a cam ridge 13 generally aligned with a stem flange 14 by which the head is connected in spaced relation with respect to the supporting flange portion 8. At their surfaces nearest the connecting stem flange 14, the shoulder portions 11 and 12 define reentrant angles therewith providing interlock hooks engageable with interlock hook flanges 15 and 17 respectively of the groove element 7. Said hook flanges generally converge toward one another and are spread open to receive the head 10 therebetween when said head is pressed into said groove element 7 until the head is fully received in a groove 18 of said groove element 7 generally complementary to the head and within which the head is interlocked by interengagement of the head shoulder hook portions 11 and 12 and the groove hook flanges 15 and 17. Trhough this arrangement, as indicated, the head and groove elements 5 and 7 are adapted to be interlockingly engaged by being pressed together and to be separated when forcably pulled apart, as by means of a generally U-shaped slider 19 (FIGS. 2 and 3).
By preference, the slider 19 is of the kind described din my U.S. Pat. No. 3,426,396, including a flat back plate 20 adapted to run along free edges 21 on the upper ends of the sections of the flange portions 8 and 9 as shown in the drawing. Integrally formed with the back plate 20 and extending in the same direction (downwardly as shown) therefrom are respective coextensive side walls 22 with an intermediate spreader finger 23 extending in the same direction as the side walls at one end of the slider. It will be appreciated, of course, that the side walls 22 are in the form of panels which are laterally divergent from a narrower end of the slider where the flange portions 8 and 9 are in the nearest approach to one another with the profiled interlocking complementary fastening structure fully interengaged, to a maximum width at the opposite end of the slider where the separating finger 23 is located, and the fastening structure rib and groove elements separated thereby. Thus, a movement of the slider 19 along the elastically flexible fastener in one direction causes the fastener to be closed and movement of the slider along the fastener in the opposite direction causes the fastener to be opened.
In order to retain the slider 19 against transverse displacement from the fastener, that is, against displacement away from the edges 21, the slider walls 22 are each provided with an inwardly projecting shoudler structure 24 flange adapted to engage respective shoulder ribs 25 and 27 on respectively outer sides of the lower sections of the flange portions 8 and 9. In a desirable arrangement, the shoulder flanges 24 are inwardly projecting nose flange formations on the terminal or free end portions of the side walls 22 having respective substantially flat shoulder surfaces 28 which extend generally perpendicularly inwardly from the inner surfaces of the side walls 22 and face toward and are parallel with the inner surface of the body plate 20 and against which generally complementary confronting shoulder surfaces 29 on the shoulder ribs 25 and 27 are engaged in the assembly. Although the shoulder flanges 24 may be provided at either end of the slider 19, a preferred location is at the narrow end where maximum assurance against unintentional pulling of the slider away from the fastener is had because the fastener is fully closed and closely confined by the slider walls 22. This is also desirable where the fastener does not have additional nose flanges located on the separating finger that engage under the fastener parts 5 and 7 at the wider end of the slider.
Substantial improvement in retention of the slider 19 on the fastener is attained by having the shoulder ribs 25 and 27 constructed and arranged to be biased firmly into the reentrant angle defined by the respective shoulder surface 28 and the adjacent inner wall surface of the slider. To this end, the ribs 25 and 27, when not in engagement with the slider, normally project to a spacing which is greater than the spacing between the inside surfaces of the slider walls 22 at least adjacent to the shoulder flanges 24. When the slider is transversely moved over the fastener, the ribs are compressively deflected inwardly toward one another to be finally received in outwardly thrusting relation between the slider walls and in retaining engagement with the slider shoulder structures.
The ribs are so designed that their outward thrust, when engaged by the slider walls, is not great enough to impair the movement of the slider along the fastener. The desirable construction of the shoulder ribs 25 and 27, for this purpose, is as shown in FIG. 1, wherein said ribs are progressively slanted from their fastener strip flange portions to their respective shoulder surfaces 29, so that in each instance said surface is normally at an angle calculated to engage firmly and uniformly with the confronting slider shoulder surface 28 when the angle A is flattened out to become substantially parallel with the engaging surface of the associated slider side wall 22, as best seen in FIG. 3. Advantageously, the progressive thickening of the ribs 25 and 27 toward the shoulders 29, and the consequent progressive resilient stiffening given to the shoulders increases up to the required limit the outward thrust pressure under compression in the full assembly, as the mass of material in the shoulders tends to spring back toward normal.
A further advantage of having the shoulder ribs 25 and 27 slanted along the angles A, generally away from the edges 21 is that in applying the slider 19 to the fastener by transverse assembly, the shoulder flanges 24 can without undue resistance press the ribs 25 and 27 inwardly toward one another, as shown in FIG. 2 until the shoulder surfaces 28 have cleared and receive the rib shoulder surfaces 29. To facilitate this action, the surfaces of the shoulder flanges 24 which face in the opposite downward direction relative to the shoulder surfaces 28 are desirably formed to provide lead-in respective slanting cam surfaces 30 which may be rounded as shown. At the ends where the slider side walls 22 have their greatest resiliency, passage of the shoulder structures 24 past the shoulder ribs 25 and 27 is further eased by expansible yielding of this part of the slider walls in response to resistance to pressing of the shoulder ribs inwardly beyond the respective normal planes of the inner surfaces of the slider side walls. Additional means to ease the assembly interengagement is afforded by respective relief slots 31 extending into the rib shoulders 29 aligned with the normal adjacent surface of the respective flange portion 8 or 9. These longitudinal slots 31 are also advantageous during the extrusion molding of the strips to avoid pulling-in deformation of the rib structure due to shrinkage in the setting or curing of the material.
Another feature in avoiding undue resistance to movement of the slider 19 into assembly with the fastener, comprises having the shoulder rib structures 25 and 27 located on the lower sections of the flange portions 8 and 9 below the complementary profiled fastening structure parts so as to permit relative inward displacement of the lower sections of the flange portions 8 and 9 in the rib areas thereof under and toward the fastening structure parts with some clearance. For example, as indicated in FIG. 1, the clearance afforded for this purpose is represented by the angular lines B. In the normal, undefomed condition of the fastener strip flange portions 8 and 9, the angles which are represented by the lines B and extending from the same point on the outer surfaces of the flange portions 8 and 9 as the angles A, are greater than the angles A, considered with respect to the flange portion outer surfaces, so that as the rib areas of the flange portions are deflected inwardly toward one another generally about axes at the convergence of the angles A and B there will be minimum pressure against the fastening structure profiles during assembly, and until the shoulder ribs have snapped into their interlocking relation with the slider on the fastener, the rib areas of the flange portions 8 and 9 while remaining inwardly deflected will remain free from pressing against the adjacent profiled fastening structure, thus avoiding excess pressure against the slider walls and enabling easy normal functioning of the slider along the length of the fastener. This relationship is enhanced by having the shoulder ribs 25 and 27 respectively of less thickness than clearance spacing between the fastening structure 5, 7 and the inner sides of those lower sections of the flange portions 8 and 9 carrying the shoulder ribs.
Although the slider 19 may be molded from a semi-hard plastic, wherein the side walls 22 are stiffly resiliently flexible at least sufficient to enable spreading apart of the terminal portions of the side walls when the shoulder structures 24 are moved transversely in engagement with the flange portions 8 and 9 past the profiled engaged fastening structure and the ribs 25 and 27, it may be desirable to form the slider 19 from metal as a die casting or molding, or to mold the same from a hard synthetic plastic material such as one of the thermo-setting materials. Where the profiled fastening structure of the fastener is of the type particularly selected for illustrative purposes herein, there is enough yieldability in the connecting web flange 14 and adjacent portions of the fastening structure to enable sufficient elastic deformation while moving the slider shoulder flanges 24 past the fastening structure along the flange portions 8 and 9 for transverse relative assembly movement, even though the shoulder flanges 24 do not yield during the assembly action.
After full assembly of the slider 19 with the fastener has been effected, not only does the resilience of the mass of the shoulder ribs 25 and 27 and the contiguous area of the flange portions 8 and 9 function to maintain a firm interlocked relation to the shoulder flanges 24 of the slider, but the adjacency of the inner surfaces of the flange portions 8 and 9 to the adjacent portion of the groove element 7 also serves to impede back-off of the shoulder ribs, because to escape the shoulder flanges 24, the deflection of the flange portions 8 and 9 must be to the extent of causing compression of the adjacent portion of the hook element 7 as shown in FIG. 2, thus adding the resistance to deformation of that portion of the element 7 to the resistance to deflectional deformation of the flange portions 8 and 9 and the ribs 25 and 27. In addition, by reason of the partial separation of the ribs 25 and 27 by the slots 31, even though compressively closed in the assembled relationship of the parts, the shoulder ribs can remain in their interlocking relation to the slider shoulder flanges 24 while permitting free deflectional yielding of the flange lower sections of the portions 8 and 9 below the ribs to a substantial extent as indicated in dash outline, for example, in FIG. 3 without affecting the shoulder ribs. Pulling forces on the flange portions 8 and 9 are also more effectively resisted because of the separation effected by the slots 31 because the shouldering portions of the ribs by compressing against the shoulder flanges 24 develop increasing resistance to release from the shoulder portions as the pulling force increases.
An additional advantage of ribs 25 and 27, is, that if properly designed, when they are in assembled relationship with the slider, they keep the lower part of the flanges 8 and 9 away from slider shoulder structure inner edge tips 32 and 33, which have a tendency to cut the flanges when moved back and forth in normal use. This can be accomplished by having the ribs thicker than the width of the shoulder structures. As shown, the lower slanting surfaces 30 of the slider flanges 24 extend generally outwardly from the respective inner edges 32 and 33.
It will be understood that variations and modifications may be effected without departing from the spirit and scope of the novel concepts of this invention.