US1076539A

US1076539A - Extension-tower.

Info

Publication number: US1076539A
Application number: US68003512A
Authority: US
Inventors: John L Ackley
Original assignee: Individual
Current assignee: Individual
Priority date: 1912-02-26
Filing date: 1912-02-26
Publication date: 1913-10-21
Anticipated expiration: 1930-10-21

Description

J. L. AGKLEY. EXTENSION TOWER. APPLICATION FILED P31126, 1912.

Patented 0G13. 21, 19.13.

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ATTORNEY J.L.AGKLBY. EXTENSION TOWER. APPLICATION FILED FEB.26, 1912.

lg@ Patented 001.21, 1913.

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k.) @E 1 Nb Q1 Q\ cnlnn Q o) Gbz\\ S (t v W z\ 5 @C @o m 1 N, \f l 1..' E' N m I m 1 I b` I S N INVENTOR, WITNEssEs .19 U] ma( BY o] j ATTORNEY WITNESSES J. L. ACKLEY. EXTENSION TOWER. APPLIGATION FILED Plaze, 1912.

Patented 00L 2i, 1913.

4 SHEETS-SHEET 3.

ATTORNEY WITNESSES J. L. AGKLEY.

EXTENSION TOWER.

APPLICATION FILED IEB.26, 1912.

Patented Oct. 21, 1913.

4 SHEETS-SHEET 4.

ATTORN EY nn'rrno s'rnfrns engem, onnion.

JOHN L. AGKLEY, or PENN veit, New YORK.

XTniisIoN-frownn intense.

i Specification of Letters Batent. Application filed ebrnery 26, lil-1e. Serial No. 680,035.

To 'al/Z whom it may concern.'

Be it known that l, Jcniv L. Acnnnv, a 'Citizen of the United States, residing at Penn Yan, in the county of Yates and State of New York, have invented a new and neeful ExtensionTower, of whichthe followthe net designed to receive persons from otherwise inaccessible points in buildings Without the necessity of an extended fall to the net.

Y While the invention in sement its pan tieulars is not limited to a portable struc; tuie, nor to a fire escape, the description of the invention Will be largely directed to the invention es embodied in e ille escape, and to this end the invention comprises suitable automobile truck on which there' is mounted a frame provided with corner posts capable of being extended on telesooped., these corner posts carrying :t 'suitable net, which latter by the extension 'of the corner posts may be brought in easy jumping distance to the point from which it is desirable to rescue a person or persons, whereby the extent of tall ina he so reduced that there is no danger of iniury to the person landing in the net.

By. the present invention provision is made for the elevation or lowering of the tower by the propellin povvei of the ant-omobile truck through evic'es n liioh may be controlled at will, `sind in addition to the het there may be provided/ a supplemental.

border net movable into position as the tower is elevated .to increase the spread of the net, whereby any extended j'uinp by the person to be rescued in order to reaeh the net is avoided, while thenet extension is so nrranged that a persen lending on the extension Will be directed into the :nain body of the netl from vvhinliaecldental escape is inipossible.

When the devine is employe-d in nonne@v tion with a 'nre esea'pe en appropriate ninnbe extended or telescoped` ber of separate but operatively connected telescoping devices are provided to 'carry the net 'or' other means for receiving the perf sons, but 'when the invention is employed for some other purposesa sinle one of the telesoo ing devices may be suiiici'en't.

Wlii e in the drawings there is shown a practical embodiment of the invention, and from the drawings talen in connection with the accom anying specilication of which the drawin orm a part, there may be obtained a 'comp ete understanding 'oi the invention, tliela ter is by no means yconnned 'to 'any Astrict conformity With the showing of the drawings, for it susceptible oi various changes and modifications Without making any material depaitnve from the salient few tures of the invention.

in the drawings -Figure l is a sideeievn'tion of a portion ci in automobile truck with the invention applied in the torni of e fire escape. Fig. 2 is a plan view of the structure shovvn in Fig. l, some prts oi the Atruck being omitted. Fig. 3 is a section on the line 3 3 0i Fig. l ont drawn to a larger sca-le. liig. ,4 is a section on the line l- 4 of Fig. l but drawn to n larger scale. Y Fig. 5 is an elevation of the structure of Fie. e as viewed from Ithe right bend lside tiereoi with some parts broken aivay 'and partsin section on the line Fig. (i is a section on the line 6- -b oi Fig. 4. Fig. 7 is a rearl elevation of the device 'oi Fig. l. Fig. 8 is an elevation oi the iront end of the automobile trncl; shown in Figa' l with some parts omitted. l

Referring to the drawings, there is shown a frame 1 which may be oi general rectangular sha-pe, and this frame is citrrled by Wheels 2, 3, through the intermediary of springs Ltan-d Afront and rear cradles 5, e, respectively, saidI 'cradles being vconnected by a. pivot 7 to a suitable portion of the frame i, en that by mechanism te be describedI the franse 1 may be rockedlon a longitudinal axis coincident withv the pivots 7 With respect to-the Wheels 2 and 3. The mnner oi supporting the frame 'l is not material to the resent invention and nenne no special -detailed desoription. thereof is deemed necessary, and the shovving of the dravvings may be taken es typic Y i any supporting means fei- ,th'e neme i, 4nfljiether portable or not. l

in the drawn-gein@ trame 1 is provided other- 5-5 of Fig'. 4...

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`with tnthed arts e et' epprepriate peinte, i

"and these arcs are engaged by pinions 9 on commonly employed in automobile trucks,

and the engine is assumed to be coupled to a drive shaft 12 which may extend longitudinally of the frame 1 andl is connected by a universaljoint 13 to a continuation 14 extended to reversing gear typified by a casing 15, and as such reversing and speed changing gear may follow the usual practice in automobiles, no attempt has been .made to illustrate any such gearing further than to show its outer casing. From .the gearing typified by the casing 15 the power shaft is continued to the rear axle 16 of the truck, which axle is assumed to drive the wheels 2. The power shaft 14 at an appropriate point carries a bevel gear 17, and spaced from the bevel gear 17 is another bevel gear 18 also mounted on the power shaft.

The frame 1 carries two journal frames 19 and 2O in which is mounted a countershaft 21Ihaving suitable bearings in the journal frame 20 and also in the journal frame 19, the shaft between these frames including a universal coupling 22, so that the end of the shaft mounted on the frame 19 may be moved wit-h'relation to the portion of the shaft mounted in the frame l20. The end of the shaft' mounted in the frame 19 carries a bevel gear wheel 23 designed to mesh with either pinion 17 or 18, but not both at the same time, and for this purpose the end of t-he shafti 21 carrying the gear wheel 23 is provided with a bearing 24 on l,the frame 19 in which 1t may be moved about the uni.- versal coupling 22 to carry the gear wheel 23 into mesh with either pinion 17 or 18.

The adjustable end of the .shaft 21 is con-4 nected by a link 25 to an arm 26 on a rock shaft 27 traversing the frame 1 and at one end provided with an operating lever 28 by means of-"which the shaft 27 maybe rocked in. one direction or gear wheel 23.

The shaft 21 extends beyond' one side of theframe 1 and there carries a gear "wheel 29, which in turn meshes with another gear wheel 30 on a counter-shaft 3 1 extending transversely of the framev 1 vand suitably journaled thereon. The shaft 31 carries a the other to shift the bevel pinion 32 meshing with another bevel pinion 33 on one end of a shaft 34 extendmg lengthwise of the frame, adjacent one 'bearing carried by the frame 20. That end of the shaft 34 remote from the pinion 33 carries another bevel pinion 35 meshing with a bevel pinion 36 on a shaft 37 traversing the frame 1 near what may be termed the rear end of the frame and suitably journaled therein.

The gear wheel 30 on the shaft-31 is suitably shaped to form one member of a clutch, while mounted on the shaft 31l are clutch shoes 38 in operative relation to theclutch portion of the gear 30, the shoes 38 being carried by toggles 39 in turn connected to a sleeve 40 keyed to the shaft 31 and controlled by a yoke 41 carried by a lever 42 whereby the sleeve 40 may be shifted lengthwise of the shaft 31. `The sleeve 40 also carries other clutch shoes 43 by toggles 44 and these clutch shoes are iny operative relation to a clutch member 45 secured to afixed part of the apparatus, as will hereinafter appear, wherefore the clutch member 45 and the clutch shoes 43 constitute a brake for a purpose which will also presently appear. The parts are so proportioned that when the sleeve 40 is in an intermediate position the

clutch shoes

38 and 43 are both inactive and may, rotate with the shaft 31, or the latter may be at rest while the gear wheel 30 is rotating.

When the gear wheel 23 is in engagement with one of the pinions 17 or 18, say the pinion 17, and the prime mover of the automobile is in motion, the shaft 21 is rotated in one direction and the

gear wheels

29 and 30 participate in such rotative movement. If, now, the clutch shoes 38 bemoved into engagement with the clutch portion of the gear wheel 30, the rotative movement of the gear 30 is impartedto the shaft 31 and through the intermediary of the shaft 34 to the shaft 37. If the gear wheel 23 engages the pinion 18 instead of thepinion 17, the direction of rotation of the shaft '21 is reversed and the direction of rotation ofthe parts driven by the shaft 21 is also reversed.- 1f the gear wheel 23 be placed in an intermediate position between the pinions 17 and 18, then no power is .transmitted from the prime mover to the shaft 21. If a force be applied to the shaft 31 tending to rotate the same when unooupled from the gear 30 this force may be vresisted by. moving the brake shoes 43 into engagement with the fixed brake member 45 and the rotation of the shaft 31 may be slowed or stopped, in accordance with the braking force. The two shafts l31 and 37 are so connected by the intermediate shaft 34 that they will rotate in the same direction.

Mounted at suitable points on the frame 1, and in the particular showing of the drawings near the rear ends of the side members of the frame and at other points toward the front of the side members of the frame, are posts 46 each composed of spaced

side members

47, 48, joined at appropriate interv-als by spacing straps 49, the` post therefor' being a hollow structure and it is to the side member 48 of this post that the brake member is secured, as by brackets 50, to one of which one end of the lever 42 is pivoted, the other end of this lever being connected to one end of a pair 0f oined links 51, the other end of which joined links is pivoted to the side member 48 of the post 46. The lever 42 is urged constantly in one direction by a. contract-ile spring 52 linterposed between and connected to the lever and the post 46. Extending transversely of the links 51 at their point of connection and in underriding relation to these links is a lever 53 at one end carried pivotally by a bracket 54 and at the other end provided with a suitable handle whereby the lever may be readily manipulated. Connected to the links 51 at their junction point is one end of a chain orother like member 55, the other end of which is connected tol one end of a lever 56 pivoted to the side member 48 at a higher point than the lever 53, the lever 56 answering a-purpose lto be hereinafter explained. l

Housed with-in the post 46 are telescoping members57, 58, respectively, each made up of side plates and connecting yokes, which latter will be referred to as needed in the following description, it being understood that. the

members

57 and 58 are of hollow construction to fit one within the other and while only two telescoping membersare disclosed inthe drawings for the sake of simplicity of illustratiom it will be understood that any number of these telescoping members may be employed, the post 46 being appropriately enlarged where more telescoping members are employed. The lower end of the post 46 is traversed by the shaft 31 and within the post this shaft carries a sprocket wheel 59 having a hub 60 on one side thereof, the sprocket wheel being dis placed to one side of the-center line of the post.v Mounted on the shaft 31 as a pivot is a yoke 61 in straddling relation to the sprocket wheel 59 and the hub 60, and the yoke carries one end of an arm 62 extending upwardly through the post 46, it being understood that the post 46 is in operation substantially upright. The other or upper end 'of the arm 62 is formed with a yoke 63 between the ends of which there extends a shaft 64 on which is mounted a' lsprocket wheel 65 and a pinion 66, the sprocket wheel and pinion moving together.` Fast to the yoke 64 is another yoke 67 extending from the yoke 64 in a direction substantially perpendicular thereto for a purpose which will presently appear. Extending around the

pinions

59 and 65 is a sprocket chain 68 so that when the shaft 31 is' rotated the pinion i 59 being also rotated, motion is transmitted to the pinion 66 through the chain 68 and sprocket pinion 65.

Extending longitudinally of the telescoping member 58 about midway between the sides thereof is a rack bar 69 fast at what constitutes the upperI end of the rack bar to a yoke 7 0 constituting one of the means for holding the side plates of the telescoping member 58 in spaced relation. Near the lower end the rack bar 69 is fast to another cross piece or yoke 71 connected at its ends to the side plates of the telescopin'g member 58 and it will be understood that, as many of these cross pieces or yokes as may be necessary are employed, short telescoping members needing fewer of these cross pieces than long ones, and in the showing of the drawings the telescoping members are purposely made quite short in order that the scaleof illustration may be sufficiently large to be legible. The lower end 72 of the rack 69v is thinned so that the teeth approach the rear face of the rack for a purpose which will presently appear. The rear face of the thinned portion 62, that is, the face remote from the teeth, is recessed, as indicated at 73 and within this recessed portion there is secured a spring 74 which. may be a flat spring made fast at one end to the rack bar and at the other end this spring carries a pin 75 projecting through the rack bar into the space between two adjacent teeth. This recess adjacent the pin 75 is provided with a shoulder 76 spaced from the end ofv the spring carrying the pin. v

rl`he telescoping' member 57 is provided with a rack bar 77 made fast at the ends to yokes 78 serving as spacers for the side plates of the telescoping member 57 and the toothed side of the rack bar 77 engages or is closely adjacent to, the rear face of thc rack bar 69, this rear face being the face remote from the teeth of the rack bar. The member 58 has an extension 79 above the upper end of the rack bar 69 and the member 57 has an extension 80 above the upper end of the rack b'ar 77. Fastto another yoke member 78 of the, memberJ 57 is one end of a spring 81, the other end -of which is formed with a tooth 82 so positioned as to engage the rear face of the rack bar 69 and when the latter has traveled a sufficient distance to bring the recess 73 into coincidence with the tooth 82 the latter will snap into said recess into the path of the shoulder 76 to be engaged thereby, so that then a f urther elevating movement of the telescoping 'member 58 will carry the telescoping mem- .66 passes from engagement with the rack 69 into engagement with the rack 77. On

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the return movement of the parts a tooth of the pinion 66 engages the pin 75 and forces the spring 74 in a direction to in turn force the spring 81 so that its tooth 82 is without the recess 73 and then the rack bar 69 may drop without further engagement with the spring 81.

The telescoping member 58 is provided at suitably7 spaced points with brackets 83 between which there extends a bar 84 in position to engage the yoke 67 and so hold the pinion 66 in engagement with the rack bar 69 while the bar 84 is in engagement with the yoke 67. The telescoping member 57 is provided with spaced brackets 85 carrylng a bar 86 nearer the center line of the telescoping` structure than is the bar 84, but the upper end of the bar 86 bends outwardly with a gentle curve, as indicated )at 87, until coincident with the bar 84.

lVhile the telescoping section 57 is being raised by t-hepinion66, the bar 84 maintains the engagement of the pinion with the rack har G9 until thelgently curved'portion 87 of the bar 86 is reached andthis is so located thatl it coincides at the time with the thinned portion 72 of the rack bar 69 and as the telescoping, section 57 then begins to rise the cam action of the portion 87 serves to torce the pinion 66 into engagement with the thinning portion of the rack bar 69 and ultimately into engagement withtlie ,rack har 77, there holding it, and ot course when the parts are telescoped instead of projected the reverse action takes place.

Fast to the end 79 of the telescoping section 58 is a finger 88 having one end in position to engage that arm of the lever 56 remote from the one connected to the chain 55 as the parts approach the telescoped posi-- tion` whereby the lock of the links 51 is broken and the lever 42 is moved by the action of the spring 52 until the clutch shoes 88 are loosened from the gear 30 and the shatt- 81 therefore ceases to rotate because uncoupled Jfrom the bar, and the parts remain 1uiescent in the telescoped posit-ion.

The upper ends of the telescoping mem hers 58 are designed to carry between them a net 89 which may be in the nature of a life net. such as is employed in connection with lire ghting apparatus, and by projecting the. telescoping members this net may be carried to a suliciently high/point above the ground or other support for the apparatus to bring` the net within easy jumping distance of endangered persons in case of a tire, and when the endangered persons have landed in the net theapparatus may be lowered and such persons removed. To'

brace the struct-ure the telescoping members wherever necessary may be joined by conV necting beams 90, so that the tendency of the impact of the saved person on landing in the net to collapse the telescoping members toward a common point is resisted.

It frequently happens that the spread of the net as defined by the telescoping corner posts upholding it is insufficient, wherefore each sect-ion 58 on the extension 79 thereof carries an arm 91 which may be soformed as to straddle the end 79, and is carried by an arborr92 traversing the extension 79 at one end havingl fast thereto a mutilated gear pinion 98. Fast to the fixed post 48 is an upright rack 94 in the path of the teeth of the pinion 93, so that as the section .58 is lowered. to its telescoping position the pinion 98 is given a partial turn by the rack 94. The movement of the pinion is sulficient to rock the arm 91 from a pendent p0- ,sition which it assumes when the parts are telescoped to a positionsomewhat higher than the horizontal, and as this vlast named position is approached a pawl 95 pivoted on the upper end of the extension 79 ofthe sectionl 58 and normally engaged by the rack 95 drops until a tooth 96 on thepawl falls into a notch 97 in the gear or pinion 93, thereby locking the latter against rotation in either direction, the arm 91 then being in the elevated position. /Vhen the parts are lowered to the telescoping position the free end of the pawl is engaged by the rack 94 and the tooth 96 is lifted ontI of the notch 97 just as the rack 94 engages the gear or pinion 93. 1n order that the paWl 95 may move promptly toward the gear 93, the pawl is controlled by a spring 98 tending to move it toward the gear or pinion 98. The arms '91 carry net sections 99 so disposed that when the arms are in the elevated position these sections will constitute continuations of the net 89 around the margins thereof and the outer edges of these marginal nets being more elevated than the inner edges the body of a person landing on the marginal nets will b e directed toward the main net- 89 and so protected from injury. Since the structure is elevated by power, it is desirable that when the full elevation is reached the power should be thrown offaw tomatically, and for this purpose the bracket 85 has attached thereto, or is continued as lug 100 so positioned that when the member 57 has reached the upper limit of its travel this lug engages the lever 5,6 o-n the end of which the chain 55 is attached and lifts this end of the leverl to throw the clutch shoes 38 out of engagement with the gear 30 and throw the brake shoes 43 into engagement with vthe brake member 45, by the spring 52 the m0- mentum of the parts being suiicient to cause the slight movement necessary after the power has been cut off. I

lf it be assumed that the parts are in the position shown in Fig. 1 whenthe structure is to be used as a life net support has been Lonate@ positioned with reference to the endangered persons, the truck engine is not stopped, but is allowedv to run continuously and the lever 28 is operated to throw the gear 23 into engagement with the proper one of the plnions 17 or 18. Now the gear wheel 3() ismoving in the proper direction and the lever 53 is manipulated to pullthe links 51 in a direction to force the clutch shoes 38 into engage-K ment with the gear 30. The shaft 31 begins to rotate and through` the connections already described and in the manner already described causes the member 58 to rise, to be followed by the member 57,- and this continues unless previouslyystopped by a manipulation of the lever 53'fby hand, until the lng 100 engages the lever 56, thus pulling up on the joined ends of the links 51 and causing the movement of the clutch shoes 38, out of engagement with the gear 30 and the brake shoes 43 into engagement with lthe brake wheel 45, thereb arresting `further upward movement wit out, however, the necessity of stopping the "engine, vIf the parts 'are not to be elevated to so great anv extent a manipulation of the Alever 53 by hand Vwill stop the elevating movement 'at anypoint desired. lf it now be wished to lower the structure, 'the lever 28 is moved in a direction to reverse the rotation of the gear 30 and then lthe lever 53 is moved inthe direction to straighten the links 51, thus again coupling the shaft 31 to the gear 30, but the latter now rotating in a direction opposite. from that `first considered will cause a re versal of movement of the parts until the' telescoping is completed and at the last portion of the telescoping action the finger 88 engages the lever 56 and once more breaks the alinement of the links 51, but this movement need only be sufiicient to release the clutch shoes 38 from the gear 30, so that movement of the lever 53 in a direction to again-clutch the shaft 31 tothe gear 30 need be but slight. i l

It is evident that when' the invention is employed in connection with other structures than fire escapes a single telescopingl rial, and for this purpose a single telescop-vv ing structure will usually be suiiicient, al-. though this does not preclude the use of more telescoping structures where greater strength andfrigidity is desired. 0f course, in cases where the invention is used simply -as an elevator, the portable feature may be ployed, and while that section which is pro jected to the highest point will be constructed asis the sectio'n'in 58 and that section which is projected to the least height will be constructedas is the section 57, intermediate' 'sect-ions will each be provided with a rack bar 69 and an adjiisting-bar 86 for the pinion 66, so that as a section approaches the upper range of its movement with respect to the pinion 66 the latter will be forced into engagement with the ,next' succeeding rack bar as already described.

Whilethe rack'bars are shown as occupying a considerable portion of the thickness of the structure in the drawings, it will be understood that in practice theymre not made so bulky in proportion to the other 'parts as indicated in the drawings, and that any suitable means may be employed for` nesting the rack bars `so that they occupy less' space.`

What lis claimed is v l 1. An extension tower comprising a series of telescoping elements 'each inner onel being provided with a rack bar in front of the rack bar of the next larger element, an actuating pinion for the rack bars, and means for moving the pinion into andout of engagement with thegrack bars succes-v sively.

2. An extension tower comprising a ser1es of telescopmg elements, each inner one being provided' with a rack bar in front of the rack bar of the next larger element, an actuating pinion for the vrack bars, and means for movingthepinion into aiid .out

of engagement with the rack bars succesltively, the teeth of a -rack bar at what constitutes the lower end. thereof approaching the teeth of the next succeeding rack bar which said first-named rack bar overlies.

3. An extension structure comprising a series of telescopin members each provided with a rack bar, t e rack bar of an inner member overlying the rack bar' of a next `successive larger member with the 'teeth at the end constituting the lower end of the rack bar approaching the teeth of the rack bar which fit overlies, a pinion common to all the rack bars and adaptedto engage them successively; and means carried by a larger',

telescoping section for forcing'the pinion" into engagement with an underlying rack bar on passing lfrom a precedlng overlying one.

"prising a relatively fixed hollow member,

with the rack bar carried by said section [inner section, the pinion being 'provided' 55,

other telescoping members movable into and out of the fixed member and with relation one to the other and each provided withy a rack bar With that of an inner member overlying that of the next outer vmember,V the rack bar of an inner member having the toothed portion which constitutes its lower end approaching the toothed portion of the rack bar it overlies, a pinion carried by the relatively stationary member in position to engage theteeth of the rack4 bars and movable bodily in a'direction substantially perpendicular to Ethe movement of the rack bars, andv means carried by each telescoping section for causing a bodily movement of the pinion into engagement.

on its passage from the rack bar of the next preceding inner section.

6. A telescoping extension structure comprising a relatively fixed hollowA member, other telescoping members movable into and out of the fixed member and withrelatio one to the otherand each provided with a rack bar with that of an inner member overlying that of the next outer member, the rack bar of an inner member having the toothed portion-which constitutes its lower end approaching the toothed portion of the rack bar it overlies, a pinion carried by the relatively stationary member in `position to engage the teeth of the rack bars and movable bodily in a direction substantially perpendicularY to the movement of the rack bars, and means carried by each telescoping section for causing av bodily movementu ot the pinion into engagement with the rack bar carried by said section on its passage from the rack bar of the next preceding with a supporting' arm vpivotally mounted inthe relatively fixed section, and driving means for the pinion extending from the) pivot pointgof the arm to said pinion.

7. A telescoping extension structure comprising a relativeiy fixed hollow member, other telescoping members movable into and out of the fixed member and with relation4 `one to the other and each provided with a rack bar with that of an inner member overlying 'that of the next outer member, the

track bar ofv an inner member having the toothed portion which constitutes its lower end approaching the' toothed portion of the rack bar it overlies, a pinion carried by the relatively stationary member in position to engage the teeth of the rack bars and movable bodily in a direction substantially perpendicular to the movement of the rack bars, and means carried by each telescoping section for causing a bodily movement of the.

.pinion into engagement with the rack bar carried by said section on its passage from the rack bar of the next preceding inner sec- ;tion, an outer telescoping section being provided with a catch forengaging the next inner Sectio-n on the projection of the inner section at the limit of its projection to cause "the participation of the next outer section in the projecting movement of the Said in ner section.

8. A telescoping extension structure comprising a relatively fixed hollow member,

vother telescoping members movable int-o and out of the'ixed member and with relation one to the other and each provided with a rack bar with that of an inner member overlying that of the next outer member, the rack bar of an inner member having the toothed portion whichconstitutes its llower end approaching the toothed portion of the rack bar it overlies, a -pihion carried by the relatively stationary member in position to engage the teeth of 'the rack bars and movable bodily in a direction substantially perpendicular to the movement ofthe rack bars, and means carried by each telescoping section for causing a bodily movement of the pinion into engagement with the rack bar carried by said section bn .itspassage from the rack bar. of' the -nextpreceding inner section, anouter telescoping section being provided with a catch for engaging the next inner section on the projection of vthe inner section at the vlimit of its projection to cause the participation of the next outer section :in the'projecting movement of the said innervsection, saidatch comprising a spring member having a constant tendency toward the rack bar of the next inner section and said rack bar being provided with an elastically constrained pin in the path of the teeth of the pinionand in position to disengage the elastically constrained member from the said rack bar.

9.` An'extension tower comprisinga series .of telescoping members, power means for projecting the telescoping members and including coupling mea-ns, an operating member for the coupling means having a normal tendency toward the uncoupled position and provided with locking means for holding it 1n the active position, a pivoted yarm connected tothe .coupling means, andspaced i members carried by different telescoping members in position to move .the pivoted ries of telescoping incassa arm in a direction to release the operating member toits normal tendency at the limits of both projection and retraction of the telescoping members.

10. A n ei'tension tower comprising'a series of telescoping members, power means for projecting the telescoping members and including coupling means, an operating member for the coupling means having a normal tendency toward the uncoupled position and provided with locking means for holding it in the active position, a pivoted arm connected to the coupling` means, and spaced members carried by different tele'- scoping members in position to move the pivoted arm in a direction to release the operating member vto its` normal tendency at the limits of both projection and retraction of the telescoping members, said coupling means being'provided with manuallyoperable means constituting the` sole means for.

and retraction of the telescoping members to.

cause the release of the clutch member to its normal tendency.

, 12. An. extension tower comprising a semembers, 4power means for project-ing and retracting the telescoping members and including a clutch structure, an operating member for the clutch structure having a normal tendency in a di- 'rect-io'n to move the clutchstructure to the unclutched position and there maintain it, means connected to the operating member for the clutch structure and movable to re lease the clutch structure to its normal tend# ency, and stop members carried bythe. upper and lower telescoping members in position to engage the last named means to move it in the same direction at both extremes of projection and retraction of the telescoping members to cause the uncoupling ot' said telescoping members from the power means at said extremes of movement.

13. An extension tower comprising a relatively fixed member and telescoping members movable successively into and out of the fixed member,l actuating means for the telescoping members, power means for the actuating .means, a clutch interposed be'n tween the power means and the actuating means for coupling the power means to and uncoupling the power means trom the actui ating scoping members actuation, a

means, a lever controlling the clutch, a toggle locking and actuating means for the lever, another lever connected to the toggle and movable to flex the toggle, and stop members carried by the inner and outer telelast-named-lever to flex the toggle at the respectivelimits of extension and retraction of the telescoping members.

"14. An extension tower comprising a relativelyffixed member,-telescoping members movable intoand out of the fixed'l member, a shaft carried by the fixed member near the lower end thereof when the said fixed member is in operative position, a clutch carried by the shaft, means for actuating the shaft through the clutch, actuating vmeans shaft, an operating toggle member controlling the clutch lever, and means for lexing the toggle to uncouple the clutch at the' extremes of moven ment of the telescoping members in either direction.

15. An extension tower having a relatively fixed member and telescoping members carried thereby, a rack carried in position to engage the by the tor the telescoping members loperated by the l lever for the clutch, a

fixed member, a pinion carried by one of the ,telescoping members, a pawl carried by the telescoping member having the pinion and movable into and out of locking engagement with the pinion, and an arm actuated by t-he pinion when engaged by the rack.

16'. An extension tower having a relatively xed member and telescoping members carried thereby, a rack carried by the fixed member, a pinion carried by one of the telesco-ping members`,.a pawl carried by the telescoping member having the pinion and movable into and out of locking engagement with the pinion, and an arm acf tuated by the pinion when engaged by the rack, said rack being located in the path of the pawl to `disengage the same from the pinlion when the latter is engaged by the rac r.

17. il. life net structure comprising a suitable support, spaced telescoping members carried thereby, connections between said telescoping members for their simultaneous life net extending between and carried at the corners by the telescoping members, rockable arms carried and actuated by the telescoping membersiand extend- .ing outwardly therefrom at substantially bisecting relationto the corners of the lite net, and nets carried by the rockable armsl supplemental toand in surrounding relation to the outer edges of the life net.

18. A life net structure comprising a suitable support, spaced telescoping members carried thereby, means for the simultaneous actuation of the telescoping members, a life net extending between the telescoping'members and at the corners connected to respective telescoping members, other nets in surroundingrelation to the {irstnamed net and exterior to the telescoping 'members and supporter thereby, and

an elevated position Iwhen the members are expanded, means and 'the telescopmg members having telescoping ooacting connections for causing the stated scoping structures, and netsearried by the` rockable arms in position to.the exterior. and

.supplementalto the main net, the telescop-v ing members and arms being provided With coacting parte for moving the arms and nets carried thereby to a substantially pendent position when the telescoping members are retracted and to elevate the arms and spread the nets carried thereby When the telescoping members are projecte 20. In a life net structure, a series of supporting members, interconnecting means therefor for operating the telescoping members simultaneously, a net extending 'between and carried at the corgners bythe meansformoving the` last named nets to a ypendent position when ythe telescoping members are retracted and said last-named..

telescoping members, a rocker arm extending outwardly from each telescoping member in :a direction to define substantially the same angle to each ofthe two adjacent sides of the respective 'port-ion of the life'net, nets carried by the rocker arms exterior tothe rst-named net and Wholly .surrounding the latter, means for. raising thereoker arms from'the normally pendent positionr to anupwardly extending position to Spreadthe supplemental nets, and meansfor locking i the rocker armsf-.in the elevated position.

21. A life net structure comprlsing a' Wheeled Vehicle,

,45 spaced cradles carried thereby, a frame Vpivotally mounted at' the front and rear onsaid cradles, rackseg-l ments carried by the frame, pinions engaging the racks, an operating shaft carried by the cradles and in turn carrying the pmions,

spaced expansible andretractile supports carried by the frame at the forward and and 'extending between said supports, and actuating means for the supports also -carried by the frame.V l

, In testimony, that claim vthe foregoing as my, own, I have hereto affixedmy signaturein the presence of two witnesses.

l JOHN L.`ACKLEY. Witnesses;

` f E. B. REED,

- F. M. MCNIFF.

vrear portions thereof, a life net mounted on 55