Strap coupler

July 6, 1965

3,192,584

Η. E. PAPE

STRAP COUPLER

Filed April 17, 1963

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United States Patent Office

3,192,584

Patented July 6, 1965

3,192,584 STRAP COUPLER

Harry E. Pape, Norwood, Pa., assignor, by mesne assignments, to EMC Corporation, San Jose, Calif., a corporation of Delaware

Filed Apr. 17,1963, Ser. No. 273,706 3 Claims. (CI. 24—16)

This invention relates to a device for securing together overlapping ends of a strap, tape or the like used for banding boxes, bales, and other packages.

It is an object of the invention to provide a strap coupler or seal which can be applied to overlapping strap | ends without the use of tools.

I Another object of the invention is to provide a strap L coupler which may be applied with speed and facility.

“ A further object of the invention is to provide a strap coupler in the form of a sleeve so arranged as to permit a pair of strap ends to be pushed therethrough in opposite directions in overlapping relation and which then prevents withdrawal of the overlapping strap ends.

A still further object of the invention is to provide a self-locking strap coupler in the form of a sleeve through which a pair of strap ends may be pushed in opposite directions and which is so arranged that the first strap' end may be pushed therethrough from either side of the sleeve.

Still another object of the invention is to provide a self-locking strap coupler which will permit the strap to be tightened about an object after it has been engaged with the coupler.

Other and further objects, features and advantages of the invention will become apparent as the description of preferred embodiments thereof proceeds.

Referring how to the drawing:

FIG. 1 is a longitudinal mid-section through the coupler and showing the manner of inserting the first end of a strap therethrough;

FIG. 2 is a longitudinal mid-section through the coupler showing the same fully engaged with overlapping ends of a strap which is under tension;

FIG. 3 is a perspective view of one of the elements of the coupler made in accordance with one embodiment of the invention;

FIG. 4 is a perspective view showing the coupler in use;

FIG. 5 is a perspective view of one of the elements of the coupler made according to a modification of the invention; and

FIG. 6 is a broken away mid-section through one end of a coupler made in accordance with another modification of the invention.

&gt; The coupler comprises a main body or member 10 ' molded of high strength non-brittle resinous material.

I A number of suitable resins are available for forming member 10, probably the least expensive one having the desired characteristics of high tensile strength and resiliency being polypropylene. Nylon is also suitable for this purpose and since, as will presently appear, lubricity is at times desirable, polytetrafluoroethylene may be used. Other resins which readily suggest themselves for this purpose include polyesters, polyacrylonitriles, cellulose esters and ethers and the like. Member 10 is in the form of a sleeve and has a multi-walled passageway 11 extending therethrough, the lower wall of the passageway being indicated at 12 and the upper wall at 13.

A strap gripping element or device preferably formed of spring steel is generally indicated at 14 and shown in FIG. 3. Element 14 comprises an enlarged flat portion 15 which is embedded or molded within the resinous body 10 and a second portion in the form of a tab 16 extending outwardly and bent back toward flat portion 15. As shown in FIGS. 1 and 2, tab 16 slopes inwardly from the adjacent end of passageway 11 toward wall 12 and an edge 17 of the end of the tab is located just far enough away from wall 12 to permit a pair of overlapping strap ₅ ends to pass between said edge and said wall.

Also embedded within member 10 is a second element generally designated at 18 which is similar in all respects to element 14. Element 18 has a strap engaging edge 19 extending toward wall 13 of passageway 11 with just enough space between edge 19 and wall 13 to permit overlapping strap ends to pass therebetween.

In using the coupler, a strap 20 is passed about a box, bale or other package 21 to be bound and one end 22 of the strap is inserted through the passageway 11. In FIG. 1, strap end 22 is shown being introduced through the passageway from left to right and in order to guide the strap past tab 16, that is to prevent the end of the strap from being caught behind the inner face of the tab, the space behind the tab is filled with the resinous 20 material forming the main body member 10 and a curved face 23 serves to direct the end of . the strap down and past the end of the tab. The space behind the tab of gripping element 18 is also filled in by the resin of main body 10 to provide a curved guiding face 24 so that the 23 strap end 22 may be passed through the passageway from right to left if desired, just as easily as from left to right. After strap end 22 is thus extended easily completely through the passageway, the second end 25 of the strap is shoved through from the opposite end of the passage30 way in overlapping relationship with end 22.

It is contemplated that the present coupler will find its greatest utility in connection with extruded polymeric straps such as polypropylene and nylon, which have recently been introduced and are used for reinforcement 35 and closure purposes in much the same manner as the well-known steel straps. These new resinous straps are stiff enough so that the end 25 can be shoved through the passageway 11 in overlapping relationship to end 22 even though the fit is so snug that the edge 17 of tab 16 offers 40 some resistance and then additional resistance is offered as the end 25 squeezes through between strap end 22 and wall 13 in the vicinity of edge 19 of gripping device 18.

Preferably edges 17 and 19 of the gripping devices are quite sharp and when an attempt is made to with45 draw the ends of the strap, edges 17 and 19 dig into the surfaces of the strap ends and a slight movement of the strap ends in the direction of withdrawal is sufficient to flex the tab portions of the gripping device from the positions shown in FIG. 1 to the positions shown in FIG. 2, 50 whereupon the overlapping ends of the strap are wedged against the walls of passageway 11 and withdrawal is prevented. Tab 16 of element 14 and the corresponding tab of element 18 are only as wide as passageway 11 and walls 12 and 13 of the passageway are stepped outward 55 as indicated at 12' and 13' respectively toward the ends of the passageway, so that the tabs are thus free to flex. Thus, while the strap may be tightened by pulling on the end 25 after both ends have been threaded through the coupler, it does not become disengaged from the coupler 60 due to the tension of the strap about the package. To assure the digging in of edges 17 and 19 the second strap end must fit snugly and to facilitate the sliding of the strap through the passageway, walls 12 and 13 are made as smooth as possible. This sliding action is further θ³ facilitated when member 10 is molded of polytetrafluoroethylene, which has a lubricating or slippery characteristic.

Instead of forming elements 14 and 18 of spring steel „0 they may be rigid so that instead of the tab portions flexing with respect to the imbedded portions, the resionous body yields to permit some slight flexing of the elements

3,193,584 as a whole. This structural arrangement depends upon proper selection of the resin employed for molding the main body member 10. A further slight modification is to provide the gripping edges 17 and 19 with teeth or serrations but this will have a tendency to decrease the overall holding power of the coupler by possibly damaging the strap.

The main body 10 of the coupler has side walls 26 and 27, see FIG. 4, and the wedging action of the tab portions of the strap gripping elements 14 and 18 places these side walls under tension. In order to relieve the resinous material of these tensile stresses, the construction shown in FIG. 5 may be resorted to.

In FIG. 5 is shown a substantially rectangular metal sleeve 28 having inwardly directed tabs 29 and 30 extending respectively from walls 31 and 32. Walls 31 and 32 are inter-connected by side walls 33 and 34. Walls 31 and 32 correspond to the enlarged flat portions of elements 14 and 18 and tabs 29 and 30 correspond to the tabs of elements 14 and 18. In forming the complete coupler, sleeve 28 is molded within a resinous body similar to body member 10 of the previously described embodiment of the invention and in cross-section this modified coupler has the same appearance as shown in FIGS. 1 and 2. The side walls 33 and 34 of sleeve 28 are embedded within resinous side walls similar to side walls 26 and 27 and it is the metal side walls 33 and 34 which primarily support the load when the coupler side walls are placed under tension due to the wedging action of tabs 29 and 30 produced in response, to attempted withdrawal of the overlapping strap ends from the coupler.

A further slightly modified form of coupler is illustrated in FIG. 6 wherein the main resinous body is indicated at 10'. The strap receiving passageway is designated at 11', said passageway having a lower wall 12 and an upper wall 13. A strap gripping element 14' is embedded within the resinous body and is provided with a tab 16' extending toward wall 12 of the passageway. A portion of a strap gripping element 18' is indicated in this figure and it will be understood that the unshown left-hand end of the coupler bears the same relationship to the righthand end as is the case with the coupler of FIG. 1. Curved face 23' serves to direct the strap end introduced from the left past the back face of tab 16'. This embodiment of the invention differs from that of FIG. 1 in that the lower wall 12 of passageway 11' slopes upward as shown at 40 toward the right-hand end of the passageway. With this arrangement, should gripping element 14' come loose from the resionous body of the coupler, tab

16' cannot move out of passageway 11' and will therefore continue to hold the overlapping strap ends against the upwardly sloping surface 40. The gripping element 14' therefore does not need to have an enlarged portion similar to portion 15 of gripping element 14 but may be simply made of uniform width throughout.