US 2533520 A
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Patented Dec. 12, 1950 UNITED STATES PATENT OFFICE LIFESAVING NET William B. Shimp, Columbus, Ohio Application May 14, 1946, Serial No. 669,593
My invention relates to a life saving net. It has to do, more particularly, with a life saving net of the type used in fire-fighting which will be held by firemen and into which a person from above can jump in an emergency.
The most common type of life saving net now in use consists of a circular metal frame and a canvas net or disc-shaped section of canvas which is attached to the frame by a series of circumferentially -spaced shock absorbers. The frame is usually made in four sections, the adjacent ends of the sections being hinged, and locking means being provided for the hinges. This makes it possible to fold the net into overlapping quarter segments.
One of the objects of my invention is to provide a life saving net which will afford the softest and easiest possible landing for a person jumping into it, thereby lessening danger of injury to such person and to the men who hold the net.
Another object of my invention is to provide a net mechanism in which easiest possible landing is attained by constructing the net mechanism to provide the closest possible approximation of reverse acceleration (deceleration) of a freely falling body so that a body striking the net will immediately meet with minimum resist ance to take the initial shock, and, thereafter, with continually increasing resistance until the energy of the falling body is completely neutralized and it comes to rest.
Another object of my invention is to provide a life saving net in which novel cushioning means is provided for cushioning the initial impact of the falling body with the net.
Still another object of my invention. is to provide a life saving net of the general type indicated which includes novel and improved shock absorbing units for attaching the canvas net to the frame.
According to my invention, I provide a life net mechanism of the general type indicated and consisting of a circular frame supporting a canvas net by a series of circumferentially spaced shock absorbers. Above the main canvas net or disc I provide an impact cushioning pad which is spaced above the main disc and is secured to the frame by suitable relatively easily yieldable means. Since the pad is spaced above the main disc and is supported by easily yieldable means,
it will serve to cushion the initial impact of the falling body before the weight thereof is applied to the main disc. The main canvas disc is supported on the frame by shock absorbers, using 2 Claims. (01. 227-46) the differential leverage principle which apply the maximum leverage on a spring at the moment of impact and relatively less leverage on the spring in succeeding moments after the impact. Thus, the shock absorbers will offer the least resistance to movement, or fall, of the falling body during the first time unit after impact, and relatively increased resistance to movement 'in succeeding time units until equilibrium is reached. The preferred embodiment of my inventionis illustrated in' the accompanying drawingwherein similar characters of reference designate corresponding parts and wherein: Figure 1 is a plan view, partlybroken away, of my life net mechanism.
Figure 2 is a plan view of one of the shock absorbers showing it in normal condition.
Figure 3 is a plan view of the shock absorber showing its condition after a body has fallen into the net and it has been actuated. Figure 4 is a perspective view of the shock absorber and associated parts. Figure 5 is a perspective view showing the net in partially folded condition.
Figure 6 is a sectional view taken along line 5-5 of Figure 1. v
With reference to the drawing, I have illus-' trated a life net which comprises mainly, the annular frame I, a main disc 2 of canvas sup.-.v
ported on the frame by means of a plurality of circumferentially spaced shock absorbers 3, and a quilted pad s of disc form which is spaced slightly above disc 2 and is attached to the frame i by the radially extending circumferentially spaced springs 5.
The frame is made in the usual manner in four arcuate sections. Each section is formed from a tube 6 of annular cross-section and of arcuate outline. The adjacent ends of the tubes 6 are hinged together by a hinge structure 1 which is of the usual self-locking type. Each of the shock absorbers 3 is attached to the frame i by means including a, col'iar 8. The collars 8 are held in proper circumferentially spaced relationship by, means of spacer tubes 9 which are of the same arcuate outline as the tubes 5' and which slip over such tubes. These spacers 9 are disposed between the adjacent collars 8 and the ends thereof engage such collars and keep them in proper positions circumferentially of the frame. Spacers 9 also serve as non-pinch hand grips.
The edges of discs 2 and 4 are spaced from frame I. In this space the shock absorbers s cross-heads l4. Similarly, the outer ends of the inner lever arms 10 are pivoted to the opposite ends of the cross-heads M by means of theip'ivot pins IS. The inner ends of the inner-lever arms,
II! are pivoted by a pivot pin I6 to a bifurcated web attaching member l1. Theim osseheads flk have a rod IB extending through openings formed therein so that the cross-heads can be moved axially ofv the rod. The rod is disposed substanti'ail-y chordal to frame and"tange'riti'al"to the edges-of discs 2 and 4; Stop nuts warem vide'd on the ends of the rod l8 forlimitingoutward movement of the'cross heads"om-the rod and prevent axial displacement of the-"rods from the cross-heads. "Between the cross' h'e'ads Min surrounding relationshipto'the rodilB'is a; compressionspring 20. "This spring normally tends to keepthe' cross-heads 1'4 spaced apartintheir outermostpositions on the red, as shownifiFiE- uresiiand 4. "l lowe'ver, as'shown ifiFigure'Tfi', an ,i-l'iw aide 151111 On the member '11 Will cause the cros's h'ead's 14 to move" towards each otnertand compressthespringifl;
Each of the members I liisprovided. witha loop 21 .at-its inner side, Through this loop is. passed a web or strap .ZZ-which is preferably of leather and extends radially-of the canvas disc .2'. This web iszfirmlyattachedio. the :canVas-disc: '2 by means of rivets. 23.o r@other suitable fastening devices; vThus; .itwill be apparent that the disc 2 is yieldingly attached to theframe I by means of the shock absorbers .3.
The quilted pad orsdisc li is.attached.to-the frame Lin spaced relationship above the disc-2 by means of the springs 5, as previously.indieated.
'Jlheiasprings are merelycomparativelyrlightrtensionsprings. One-tend iofi-ieachspring 5 is: an-
chored-.tothei'collar 8 by'means of. an :upstanding'iiliig'; 24'" whichsisnintegral with theacol-larv 8. The otherxendizof thespring' 5 isz'anchored 3001a web'attaching, member 25. This member .251has asleep; 2 6 throu h: which; a web; tor .stitapz'ifl-uis passed. The 'web -"or.. strap:. 2T :is; preferably of leather and is attached to the pack ktbyirivetsifl or otirersu'rtable means.
lm theleuse nf thisme't, it'ivilllbeheldlin :the usual manner by a- 'crew of amen whoi'will the spacers" 9. The shtick absorbersl will: harm,
4 [0 when they are in their initial positions, as shown in Figure 2. As the attaching member I! is pulled towards the center of the frame I, this resistance to the compression of the spring is increased. Thus, a maximum of leverage on the springs 20 is applied at impact time and relatively less leverage is applied on the springs in succeeding time units. Consequently, thi allows thewgreatest movement. or. .fall, .of the falling bodyrduringthefirst time unit after' impact, and relatively less movement in succeeding time units until equilibrium is reached. This constitutes a close approximation of reverse acceleration of a xir-eelyialling body, and. an improvement on all previously used life nets.
"'The' ne'tm'ay be folded up in quarter segments 4 ini theausu'al manner, as indicated in Figure 5.
The shock absorbers 3 are outside the area of the canvas and facilitate, this folding operation. Since the shock absorbers are positioned beyond the canvas and not"beneathit thereisless danger ofthe shock-absorbersdamaging the" canvas;- Also,-since the shock absorbers are disposed'clo'se tn*the'" frame I; there-is-lessdangenof iniiury to the person fallingintd-themet. Becauseofthe arrangement "of the springs= =2Eiand" associated partsofthe shockabsorberssubstantially tangent-ial-to the canvas rather than radiallyyas -in pr'ior'ar't devices; longer springs'can be used"- and greater travel of the web or strap a'ttaching'devices willv be permitted. Consequently, the can'- vasWill be permitted to flex to a greater extent; The 'shock absorbers arefreeto shift and adjust themselves to the direction of the force" ofthe impact caused byrthe body landing: dfice'nter. When'thecanvaslias be'enreli'e'ved of the weight, the'shock absorbers willquickly .return to their original condition. 7
'SThel'ife net which I have proividedwill provide i'oi-"the easiest possible landing, inasmuchas a body. striking the netlmeetsr immediately, with minimum resistance and thereafter with continually increasing resistancauntil the energy of the falling. body is completely neutralized sandl it comes to rest. Asia corollary. to ltheabove, the body will .falL-through the maximum distancein thezfirstitimel unit after strikirigthenet (impact time) and through relatively lessxdis tancesin each? succeeding .time unit until: equilibrium is reached.- and the bodyeis at rest. My netwillsdeliver a minimum of shocketo (1)--the-=falling-body, (mi-the merrwho hold the net, and -.(3)-=the .net mechanism itself.
vVarious' other; advantages-will =be apparent from the preceding description}:thendrawingrand; the tel-lowing; claims;
i-Havingr:thusrdescribed: my invention, what: I clainnis':
1 lfi A life saving .n'et comprising an-J: annular frame, a net of annular form having its'1 edge spaced :frcm the frame; av pluralitymf -eircQimf erentially spaeed shcck absonbingunits disposed in :said space-, 'ariehoringbraekets-mountedan the frameand arichoringbrackets 'car-rie'd "by the net for connecting said unit's to the name and met, each of saidzniiits ocmprising' a irod'dispcsed sub stantialiy: chordal #to the frarna a ocmpres'sion spring-surrounding"the: od; a-pain of cro'ss' -hea'ds assc'ciatedwith the 'r'od 'ferJnnVemen-t towards and awayfrom --ea"eh l other and engaged by the spring, a pair or outer" levers h-aving their outer ends pivoted =tothe cro'ss 'h'e'ads and their inner ends pivoted to eachotl'ier-and to'saida-richoring bracket "mounted =-on"the" frame= and associated therewith, a pair of inner levers having their outer ends pivoted to the cross-heads and their inner ends pivoted to each other and to the anchoring bracket connected to the net and associated therewith, an impact cushioning pad of 5 circular outline supported slightly above said net and having its edge spaced from the frame, and means for yieldingly attaching said pad to the frame, said means including radially extending tension springs extending over the associated shock absorbing units, each of said springs having its outer end connected to said anchoring bracket mounted on the frame and its inner end connected to an anchoring bracket attached to said pad.
2. A life saving net according to claim 1 wherein the anchoring brackets on the frame comprise collars surrounding a main frame member and which are held in spaced relationship thereon by means of spacer members surrounding said main frame member.
WJLLIAM B. SHIMP.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS