US2859928A - Lifter strap for aircraft barriers - Google Patents

Description

Nov. 11, 1958 J. E. SNOW LIFTER STRAP FOR AIRCRAFT BARRIERS 2 Sheets-Sheet 1 Filed Dec. 19, 1955 INVENTOI.

Nov. 11, 1958 J. E. SNOW LIFTER STRAP FOR AIRCRAFT BARRIERS 2 Sheets-Sheet 2 Filed Dec. 19, 1955 gi 3242x279 I United rates Patent 2,859,928 LIFTER STRAP FOR AIRCRAFT BARRIERS John E. Snow, Fairborn, Ohio, assignor to Acme Precision Products, Inc., Dayton, Ohio, a corporation of Ohio Application December 19, 1955, Serial No. 553,817 Claims. (Cl. 244-110) My invention relates to that class of devices known as aircraft barriers and more particularly to the means for lifting the arresting cable into engagement with the aircraft. As described in my co-pending application Serial Number 481,591, filed January 13, l955, now Patent Number 2,770,431, the arresting cable which engages the moving aircraft is flung into the air by. means of lifter straps attached to an actuator strap that is engaged by the nose wheel of the aircraft.

The adjustment of the lifter straps heretofore known has presented difficulties because the litfer strap has been formed of one continuous piece of nylon from the actuator strap to the grommet fastened to the runway. It was bent and fastened by button clips to enfold the arresting cable in such a manner that it would fling the arresting cable into proper position upon the aircraft crashing the barrier. In practice I have provided two actuator straps and two lifter straps but they were merely for safety and not required for operation. While no failures due to malfunction of the lifter strap have been experienced, the awkward arrangement of the lifter strap fastening means has presented practical difficulties and delays in assembling the barriers foruse. One of these difliculties arises from the fact that after each engagement of the barrier by an aircraft when the barrier was reassembled, it is necessary to fasten the snap clips of the actuator straps into position and it takes considerable time since there were six buttons to snap on each lifter strap. Another difficulty presented by the button clips is that due to the continuous aircraft traffic over the equipment as it lays on the runway when not in use, the snaps tended to break loose and then upon the barrier being crashed, these worn snaps would not offer the positive resistance to opening which is required for the satisfactory functioning of the arresting cable or they would release prematurely causing unstable performance. Another disadvantage is that some of these buttons were torn at the separating of the lifter strap and some of the metal became disengaged from the lifter strap and entered the engine intakes.

The principal object of my invention is to provide a two-piece lifter strap which is severable at a predetermined pull on the lifter strap.

It is a further object of my invention to provide a twopiece lifter strap that can be quickly and easily installed around the arresting cable.

It is a further object of my invention to provide a twopiece lifter strap which forms a separable loop around the While there may be as many lifter straps as desired, each strap is formed of two pieces of material as set forth below.

My means of accomplishing the foregoing object may be apprehended more readily by having reference to the accompanying drawings in which:

Figure 1 is a vertical perspective view of my two-piece lifter strap in position;

Figure 2 is a perspective view showing my lifter strap just after contact of the actuator straps by an aircraft;

Figure 3 is a perspective view similar to Figure 2 but later in the operation;

Figure 4 is a perspective view showing the arresting cable snapped in the air by my invention;

Figure 5 is a detail perspective view showing my means of attaching one end of the actuator straps to a shear pin;

. and

arresting cable and is releasably attached to the runway. V

The loop is formed by one piece being longer than the other and being folded around the arresting cable and attached at one of its ends to an actuator strap and at its other end to the runway by a grommet, while the shorter piece is attached to another actuator strap and is sewed to the longer piece in such a manner that both pieces form the loop around the arresting cable.

It is a still further object of my invention to provide a two-piece lifter strap that i calibrated to separateupon the exertion of a predetermined pull.

Figure 6 is a perspective view of the two-piece lifter strap as used with a single actuator strap.

Similar numerals refer to similar parts throughout the specification as shown in the drawings.

Unlike my eo-pending application referred to above, it is a necessary part of my preferred embodiment of this invention to employ at least two actuator straps. I believe my invention is practical employing a single actuator strap or a plurality of actuator straps but I prefer the double actuator strap for this invention.

I provide a pair of actuator straps 2 and 3. I prefer to use nylon webbing but of course any woven synthetic or organic material could be employed. In practice I prefer to employ nylon webbing with a break strength of approximately l0,000 pounds. As is well known, a plurality of lifter straps connect the actuator straps 2 and 3 to the arresting cable 20. My lifter strap (I shall describe only one'), indicated generally as 4, is formed of two pieces of material 6 and 8 of unequal lengths. For reasons that are apparent to those skilled in the art, I prefer that the pieces 6 and 8 are also made of nylon. I provide that one end of the pieces 6 and 8 are folded over the actuator straps 2 and 3 and form thereby loops 5 when, sewed as at 10. In order to prevent lateral movement I:

provide that the loops 5 are sewed to the actuator straps: 2 and 3 as shown at 7.

As shown in the drawings, the piece 6, being the longer, is folded under the arresting cable 20 and is fastened to the runway R by the usual grommet 12. I provide that the grommet 12 will pull out of the plate in the runway upon a pull of approximately 250 pounds. The lack in the piece 6 is formed into an outside loop 14 and may be tack-stitched lightly as at 15 to hold its form. I provide a snap fastener 18 for orientation of the arresting cable 20 but this snap fastener 18 is not the equivalent of the snap fasteners 26 I provided in the co-pending application referred to above. Also for convenience I provide for a tack-stitch 16 as shown. The button or snap fastener 18 is used for the sole purpose of snapping the lifter strap 4 around the cable 20 in a manner to prevent the lifter strap 4 from being inadvertently turned inside out when placed around the cable. It serves no purpose in properly releasing the cable 20 when a predetermined load is placed on the snap 18. The snap 18 may be a glove type or lock type fastener. On the other hand, the snap fasteners 26 in my above identified copending patent serve the purpose of releasing the cable 30 when the proper load is placed upon the fasteners. On my present lifter The piece 8 is sewed adjacent its end with stitching 9 to the piece 6 just short of the loop 14 as shown. Since the loop thus formed around the arresting cable 20 is required to be of a predetermined length so that the actu- Piatented Nov. 11, 1958 main stanchions (not shown), I providethatthe ends 22 and 24-0f the actuator straps 2 and 3 are bent back and sewed to form loops 26 and 23 as shown in Figure 5. The loop 26 may be pressed inside the loop 28 and placed over a finger 36 which is pivoted on a yoke 32 by a rivet 34. I provide that the yoke 32 is bifurcated into prongs 36 and 33. These prongs 36' and 38 have holes 42 and 44 as shown. After the loops 26 and 28 are placedover the finger 3% the finger is raised into position between the prongs 36 and 38, so that the hole 40 in the finger 3% is in register with holes 42 and 44 in the prongs 36 and 38. Into these holes 40, 42, and 44, I insert a shear pin 46 with a breaking point of approximately 3,000 pounds. While I have described one such arrangement, it is understood both ends of the actuator straps 2 and 3 are so mounted.

It will be clear to those skilled in the art that the success of my invention resides in the control I achieve over the separation of the pieces 6 and 8 since itis the lifter straps which fling the arresting cable into the air. Accordingly, as set forth above, I have found in practice that the stitching 9 being composed of four rows of five-cord nylon with a breaking strength of 40 pounds sewed in approximately 4/: inch rows and cross stitched provides a satisfactory tear which is comparable to the separation of the button clips 26 heretofore employed and are much more satisfactory and consistent. While the stitching would pull out with the exertion of approximately 100 pounds direct pull on the sewing, it takes approximately 1,500 pounds to shear the threads in the tearing motion accomplished by my invention. The force necessary to accomplish this tearing of the threads results in an increased snap force being imparted to the arresting cable in its upward travel.

In Figure 3 I have indicated the position of the lifter strap just before the two pieces 6 and 8 tear apart. In this figure I have shown the position of the two pieces 6 and 8 just prior to the tearing of the stitches 9 which is clearly shown in Figure 4. It will be seen from Figure 3 that the lifter strap has already lifted the arresting cable some distance off the runway R and it will bev clear to those skilled in the art that the inertia due to the raising of this heavy wire rope of great mass accomplishes the tearing of the stitching in the manner set forth above. This permits the material surrounding the cable to be free to impart additional snap effect to the arresting cable thus increasing the velocity of its travel T above the runway.

In Figure 4 I have shown the position of the actuator straps 2 and 3 subsequent to engagement by the forward part of the aircraft. By this time the button 18 has pulled apart and the piece 6 has been torn loose from the'piece 8 at the threads 9 and the tack-stitching 15 has also torn loose. At this point, the arresting cable 20 has been flung into the air to a height of T. Due to the stitching being very accurately gauged, I have found in practice that this form of lifter strap produces an even better control and is of a more economical construction than the lifter straps heretofore in use.

Figure 6 shows the arrangement employing a single actuator strap 50. In this figure the same reference numerals with a prime added have been applied as in Figs. 1-5 to all parts other than the actuator strap 50, since these parts are in fact identical to those shown in the previously described figures. Here, however, both of the loops pass around the single actuator strap. Operation of thismodification is otherwise the same as above described.

While I have described my invention somewhat in detail, I do not intend to be limited to the particular config:

uration shown in the drawings.

What I regard as new and desire to protect by Letters Patent is:

l. A lifter strap for aircraft barriers, said lifter strap releasably attached to an aircraft runway and normally connecting a pair of stretched actuator straps to an arresting cable, said actuator straps adapted to be engaged by the forward part of a moving aircraft, said lifter strap. including releasable means connecting said actuator straps with said arresting cable and releasable upon a predeterm-ined pull on said lifter strap by said actuator straps being engaged by the forward part of a moving aircraft, said releasable means comprising at least two pieces of flexible material of unequal lengths, each piece attached at one of its ends of a separate one of said actuator straps, the longer of said pieces being releasably attached at its other end to said aircraft runway, and the shorter piece being severably attached adjacent its other end to said longer pieceintermediate the ends of said longer piece forming thereby a severable loop around said arresting cable. I 2. A lifter strap for aircraft barriers, said lifter strapreleasably attached to an aircraft runway and normallyconnecting a pair of stretched actuator straps to an arresting cable, said actautor straps adapted to be engaged by the forward part of a moving aircraft, said lifter strap including releasable means connecting said actuator straps with said arresting cable and releasable upon a predetermined pull on said lifter strap by said actuator straps being engaged by the forward part of' a moving aircraft, said releasable means comprising at least two pieces of flexible material of unequal lengths, each piece attached atone of its ends to a separate one of said actuator straps, the longer of said pieces being releasably attached at its other end to said aircraft runway, and the shorter piece being sewed adjacent its other end to said longer piece intermediate the ends of said longer piece forming thercf by a severable loop around said arresting cable.

3. A lifterstrap for aircraft barriers, said lifter strap releasably attached to an aircraft runway and normally connecting a pair of stretched actuator straps to an arresting cable, said actuator straps adapted to be engaged by the forward part of a moving aircraft, said lifter strap including releasable means connecting said actuator straps with said arresting cable and releasable upon a predetermined pull on said lifter strap by said actuator straps being engaged by the forward part of a moving aircraft, said releasable means comprising at least two pieces of woven synthetic or organic material such as nylon Wehbing of unequal lengths, each piece attached at one of its ends to a separate one of said actuator straps, the longer of said pieces being releasably attached at its other end to said aircraft runway, and the shorter piece being severably attached adjacent its other end to said longer piece intermediate the ends of said longer piece forming thereby a severable loop around said arresting cable.

4. A lifter strap for aircraft barriers, said lifter strap releasably attached to an aircraft runway and normally connecting a stretched actuator strap to an arresting cable, said actuator strap adapted to be engaged by the forward part of a moving aircraft, said lifter strap including releasable means connecting said actuator strap with said arresting cable and releasable upon a predetermined pull on said lifter strap by said actuator strap being engaged by the forward part of a moving aircraft, said releasable means comprising at least two pieces of flexible material of unequal lengths, each piece attached at one of its ends to said actuator strap, the longer of said pieces being releasably attached at its other end to said aircraft runway, and the shorter piece being severably attached adjacent its other end to said longer piece intermediate the ends of said longer piece forming thereby a severable loop around said arresting cable.

5. In a system for engaging an aircraft moving over a runway, stretched actuator strap means adapted to be supported across said runway above the surface thereof, an arresting cable normally resting adjacent said runway below said actuator strap means with the system in readiness to engage an aircraft, lifter strap means connecting said actuator strap means with said cable and releasable upon a predetermined pull exerted on said actuator strap means due to engagement thereof with the forward part of an aircraft, said lifter strap means including at least two separate members of flexible strap material at one end thereof together forming a loop around said cable, severable means of predetermined strength securing said members of strap material to each other providing for breaking of said loop under controlled conditions to impart a lifting force to said cable prior to release thereof from said lifter strap means, said lifting force operating to raise said cable for engagement with a rearward part of the aircraft, and a connection of greater strength than said severable means between said lifter strap means and said actuator strap means.

References Cited in the file of this patent American Society of Naval Engineers Journal, vol; 61, No. 2, May 1949, p. 330.

UNITED STATES PATENT OFFICE Certificate of Correction Patent No. 2,859,928 November 11, 1958 John L. Snow It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 25, for litfer read -1ifter; column 2, line &8, for lack read s1aok; column 4;, line 16, for of a separate read to a separate; line 27, for actautor read -actuator-.

Signed and sealed this 28th day of April 1959.

Attest: H T. B. MORBOW, ROBERT C. WATSON,

Attesting Ofiicer. Commissioner of Patents.

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