US 3484905 A
Description (OCR text may contain errors)
Dec. 23, 1969 R. EBERHARDT BUNDLE T I E Filed Aug. 8, 1968 /N VENTO: Rober fberzard f cffy United States Patent O 3,484,905 BUNDLE TIE Robert Eberhardt, 4142 W. Newport Ave., Chicago, Ill. 60641 Filed Aug. 8, 1968, Ser. No. 751,137 Int. 'CL B65d 63/00 U.S. Cl. 24-16 9 Claims ABSTRACT OF THE DISCLOSURE A flexible tie for a bundle of electrical conductors or the like. The tie is molded in one piece of a resilient, yet generally Shape-retaining plastic composition. At one end of the tie is a head having an aperture to admit a strap part extending from the head in order that the device may be looped around the bundle. Within the aperture is a resilient finger having an active edge to engage one of a plurality of teeth on the strap in order that the device may be locked in position about the bundle. The construction is such that more reliable engagement is obtained without the use of metal inserts or other expedients and by means which allows molding of the device in one piece in a simple, inexpensive mold.
The invention relates to a tie as set forth in the abstract and having the several objects and advantages mentioned therein.
Bundle ties of the class aforesaid are used in large quantities, and are usually in the form of a strap having an apertured head at one end including means for nonslip engagement with the strap, e.g. a pawl and teeth. Sometimes the tie has means for attaching the same and its therein-held conductors to a fixed supporting surface, and the invention tie may, alternatively, be so characterized. Regarded commercially, price is an important consideration, so that the user is encouraged, in the interest of a reliable and workmanlike installation, to use more, rather than fewer ties.
It has been known to provide a tie of the type here considered which employs a metal blade to serve as a pawl to prevent slipping of the tie following its securement` about the bundle. However, the placement of a plurality of such blades in the customary multiple-cavity mold is expensive and time-consuming. Further, since the mold is operated with the parting line in a vertical plane there exists the constant hazard of the blades dropping out or falling into a position whereat damage may occur to the mold as it is closed. As a concomitant, careful inspection of the piece parts, and the attendant expense, adds to the ultimate price. Moreover, there is the chance of the metal insert being dislodged or falling out in shipment and other handling.
The present invention employs a novel form of freestanding pawl formed integrally with the tie and which is so constructed and arranged as to define, with the aperture in the head .of the tie, a space narrower than the thickness of the strap. Since the plastic composition is choser;` to be resilient, the Strap, upon being bent and passed through the aperture may displace the pawl and, when pulled tight, one of the teeth thereon is engaged by the pawl to preclude reverse movement of the strap.
In a modified form the tie is provided with a projection adjacent the opening in the head which is so constructed as to constitute a gusset at that corner of the looped tie which Would otherwise be a right angle. It has been found that, in the absence of a projection of this Character, the conductor or conductors located at this corner tend to force the strap away from the pawl.
Other objects and advantages of the invention will become apparent from the ensuing description which, taken "ice With the accompanying drawing, discloses a preferred form in which the principles of the invention may be embodied in practice.
In this drawing:
PIG. 1 is a perspective view of a bundle tie incorporating the principles of the invention;
FIG. 2 is a side view of the same in its useful position, but no conductors are indicated;
FIG. 3 is an enlarged plan view of the head end of the tie;
FIG. 4 is a cross section taken on the line 4-4 of FIG. 3;
FIG` 5 is a cross section taken on the line 5 5 of FIG. 4; and
FIG. 6 is a cross section similar to that of FIG. 4 but with the free end of the Strap engaged by the pawl.
Regarded in its broad aspects the invention comprehends a tie for the purpose referred to which is molded in one piece of a resilient, yet generally shape-retaining plastic composition. The device includes a strap and a head at one end thereof. The head has a rectangular through opening, defining a frame, from one wall of which a pawl extends into the opening in cantilever fashion, the pawl having a strap-engaging edge adapted to abut a mating face of one of a plurality of teeth formed on the strap. The pawl is secured only at its base in order that the distal end thereof may flex readily as the strapis drawn past but will exert substantial force normal to the face of the strap in order that, upon releasing the tension applied when drawing the strap through the aperture, the selected tooth will be reliably engaged and loosening of the tie precluded. The pawl is essentially rhombohedral, one face being at the basal end where the pawl is united to the frame, and the remainder thereof being free-standing for enhanced tooth-engaging action. Preferably the aperture is provided with a strut or ledge extending transversely thereof with which the pawl is united and which serves the dual purpose of providing a rigid base for the pawl and to rigidify the aperture.
Reverting to the drawing there is shown, FIG. 1, a tie in accordance with the invention comprising an elongated strap 10 terminating at one end in a head 11. Since the device is to be comparatively rigid in order to effect its looking function, and yet be resilient to conform to the bundle being tied, the use of nylon is preferred. Obviously, other plastic compositions of similar characteristics may be substituted, e.g. polyethylene or polyvinylchloride. The Strap has a plurality of spaced teeth 13 shown, by Way of example, as having a right-angled triangular cross section with the '*vertical" face normal to the longitudinal axis of the strap and the hypothenuse face lgently sloped for ready passage past the pawl. Although such teeth are shown with the apex 15 thereof fiush with the principal face 17 of the strap, it will become apparent that the apices may be above or below such face. The end 18 of the strap is desirably provided with a tapered leading end to facilitate admission thereof into the aperture of the head.
This aperture 19 extends through the head, the rear face 21 being uninterrupted and the front face 22 having a strut or ledge 24 extending from one side face 25 of the aperture to the opposite face 25. The pawl is essentially rhombohedral and includes a basal plane 27 (indicated 'by a 1broken line) merged with the ledge 24, and such basal end is shorter than the ledge whereby to' define spaces 29, 29 at each side of the pawl. Stated otherwise, the pawl is cantilevered so that it may fiex throughout its length. The amount of flexure, it will be noted, is virtually zero at the plane 27 and increases progressively to a maximum at the corner 32 Whereat the pawl engages the tooth.
It -will be noted that the space A between the sharp distal edge 32 of the pawl and the confronting face 21 of the aperture 19 is desirably slightly less than the distance B measured from the root of a tooth 13 and the flat side of the Strap, namely, 0.032 as compared to 0.035. Thus, it is assured that, when the tie is in its active, locked condition, there is full engagement between the edge 32 of the pawl and the face 34 of the then-active tooth. Further, that the face 36 of the pawl is normal to the face 17 of the Strap, When engaged, so that this entire face is disposed in full abutment with the face 34 of the tooth, for maximum gripping eificiency.
It will also be seen that the teeth 13 are bounded on both sides by marginal ribs 41, 41. In the example, the width D of the edge 32 of the pawl is Ma and the dimension E between the ribs is %2". Thus, the pawl is not only reliably seated in a left-andright sense (FIG. 6) but in a lateral Sense also.
Desirably, the entrance to the aperture 19 is chamfered as indicated at 46 to facilitate threading of the Strap thereinto. Further, it is preferred that the dimension F of this aperture be only slightly greater than the width G of the Strap to avoid cocking of the latter and to insure full abutment of the pawl with the then-engaged tooth. In the illustrative case dimension F is 1%4" and G is 3/1 The walls of the aperture 19 and the ledge 24 are so constructed and arranged as to have greater resistance to yielding when the strap is engaged than the force against the pawl by the reaction of the bundle of wires or other components being restrained.
In devices of the general class herein referred to it has been found that, when the bundle is tied, those conductors in the corner (FIG. 2) adjacent the head tend to be crowded and therefore subjected to injury. Moreover, such crowding may tend to detract from the engagernent between the pawl and tooth. To alleviate this condition a gusset construction is introduced. For example, this may take the form of a pair of triangular projections 51, 51 or a single projection equivalent to the pair. This additional feature lends more or less smooth continuity to the interior of the loop formed when the tie is in its useful position and enables the components of the bundle to distribute themselves more uniformly. Further, by reason of its proximity to the head and the integral construction of the device, the head and the base of the pawl are lent additional rigidity.
1. A one-piece bundle tie of resilient, but generally shape-retaining material adapted to be looped upon itself in adjustable self-locking relation comprising: a strap portion having a plurality of transverse teeth spaced longitudinally thereof, a head at one end of said portion, said head having an aperture therethrough to pass the Strap, a ledge extending into said aperture from a wall thereof, said ledge having a face transverse to the plane of the Strap when the Strap is passed through the aperture, a pawl of essentially rhombohedral configuration carried by said ledge, one face of the pawl being co-planar with said ledge face and extending into said aperture, one of the sharp edges of the rhombohedral configuration extending into the path of the strap to engage a selected one of said teeth when the tie is secured around the bundle.
2. The device in accordance with claim 1 in which one of the active faces of the pawl which defines said one sharp edge is in substantially full abutment with the co- Operating face of the selected tooth when the tie is looped about the bundle,
3. The device in accordance with claim 1 in which the ledge extends between a pair of opposite walls of the aperture and the width of the pawl measured in the sarne direction as the longitudinal extent of the ledge is less than said extent, one face of the pawl constituting the tooth-abutting face and the opposite face merging into the ledge. v
4. The device in accordance with claim 1 wherein said one pawl face is shorter than said co-planar face of the ledge to provide Separation of the lateral faces of the pawl from the faces of the aperture confronting the same, whereby the pawl is free to fiex over substantially the'l entire length thereof measured from said one sharp edge.
5. The device in accordance with claim 1 wherein the teeth have a locking face normal to the longitudinal axis of the Strap and the cooperative face of the pawl is normal to the axis of the aperture whereby said cooperative face and tooth-locking face, when in locking condition, are in face-to-face abutment.
6. The device in accordance with claim 1 wherein said teeth are below the principal surface of the Strap and the inter-tooth spaces are bounded at their ends by marginal portions of the Strap.
7. A one-piece bundle tie of resilient, but generally shape-retaining material adapted to be looped upon itself in adjustable self-locking relation comprising: a Strap portion having a plurality of transverse teeth spaced longitudinally thereof, a head at one end of said portion, said head having an aperture therethrough, said aperture having a rectangular cross section defined by opposite side Walls and rear and front walls, said Strap extending out- Wardly from said front wall, a pawl of substantially rhombohedral configuration extending into the aperture, the basal end of said pawl being carried by a part of the. front wall, the acutely-angled distal edge of the pawl confronting the interior face of said rear wall, the lateral faces of said pawl being separated along their entire extent from the two opposite side walls of the aperture.
8. The device in accordance with claim 7 wherein the teeth have a locking face normal to the longitudinal axis of the Strap and the cooperative face of the pawl is normal to the axis of the aperture whereby said cooperative face and tooth-locking face, when in locking condition, are in face-to-face abutment.
9. A plastic bundle tie adapted to be looped upon itself in adjustable self-locking relation comprising: a Strap portion having a plurality of transverse teeth spaced longitudinally thereof, a head at one end of said Strap, said head having an aperture to receive the looped-over strap portion to define a space for reception of the bundle, means carried by said head to engage a selected tooth to lock the device about the bundle, said tie having a projection extending from the side of the strap to be disposed within the loop when the tie is around the bundle, said projection having a cross section in a plane parallel to the longitudinal axis of the Strap which is substantially a right-angled triangle, the Vertical face of the projection being substantially normal to said Strap and positoned to lie adjacent to the toothed face when the tie is around the bundle, the sloping face of the projection being substantially 45 in order that, when the tie is looped, the space defined by said sloping face and by the Strap at its intersection with the head has a substantially continuous interior boundary, said projection being secured to the strap head so as to provide a rigid base for the pawl and to rigidify the aperture.
References Cited UNITED STATES PATENTS 2,979,794 4/1961 Bartolo 24-17.1 3,368,247 2/1968 Orban 24-16 3,376,004 4/1968 Goldman 24-16 X DONALD A. GRIFFIN, Primary Examiner