US2951549A

US2951549A - Aerial ladder

Info

Publication number: US2951549A
Application number: US404462A
Authority: US
Inventors: Holan James Howard; Herman J Troche
Original assignee: J H HOLAN CORP
Current assignee: American LaFrance LLC; J H HOLAN CORP
Priority date: 1954-01-18
Filing date: 1954-01-18
Publication date: 1960-09-06
Anticipated expiration: 1977-09-06

Description

Sept 6, 1950 J. H. HOLAN ETAL 2,951,549

AERIAL LADDER Filed Jan. 18, 1954 7 Sheets-Sheet l Zhu/fw fors Sept 6, 1950 H. HOLAN ET AL 2,951,549

AERIAL LADDER Filed Jan. 18, 1954 '7 Sheets-Sheet 2 Sept. 6, 1960 J. H. HOLAN ET AL AERIAL LADDER 7 Sheets-Sheet 5 Filed Jan. 18, 1954 Sept 6 1960 J. H. HOLAN ET AL 2,951,549

AERIAL LADDER Filed Jan. 18, 1954 7 Sheets-Sheet 4 Sept 6, 1960 4 J. H. HOLAN ET AL 2,951,549

y i AERIAL LADDER Filed Jan. 18, 1954 '7 Sheets-Sheet 5 Sept. 6, 1960 Filed Jan. 18, 1954 J. H. HOLAN ET AL 2,951,549

AERIAL LADDER 7 Sheets-Sheet 6 /53 [50 /52f T ,/56 O Sept 5 1950 J. H. HOLAN ET AL 2,951,549

AERIAL LADDER IHIII AERIAL LADDER James Howard Holan, Rocky River, and Herman J. Troche, Fairview Park, Ohio, assignors to J. H. H olan Corporation, Cleveland, Ghio, a corporation of Ohlo Filed Jan. 18, 1954, Ser. No. 404,462

1 Claim. (Cl. 182-66) This invention relates to an aerial extension ladder for a utility vehicle or the like which is swingable and tiltable with reference to the vehicle for obtaining access to over head traffic lights, street lamps and similar objects. The invention is more particularly directed to the unitary mounting of such ladder on a vehicle support along with fluid pressure actuated mechanism for automatically effecting the ladder movements in accordance with the selective operation of la iluid pressure control system.

The design and construction of a vehicle having an aerial ladder of the type indicated requires consideration of many factors, including ilexibility of movement within the limited space of the vehicle in an ecient and `safe manner. Independent operation of various mechanisms for effecting different ladder movements requires constant attention by an operator and inherently'results in a lack of coordination between the respective movements. Accordingly, it is a principal object of this invention to provide a highly flexible aerial ladder for a vehicle which can be automatically moved to different positions relative to the vehicle in an efficient and coordinated manner` Briefly, in accordance with this invention there is provided a wheeled vehicle having an aerial ladder movably mounted on a common support along with suitable mechanism for automatically elevating, extending, and rotating the ladder. The mechanism may be selectively actuated by fluid pressure which is supplied from a control system integrally carried by the ladder mounting. In one embodiment, the source of pressure is provided by an engine driven pump carried by the ladder mounting while another embodiment utilizes a power take-olf arrangement from the vehicle drive to operate a pump for supplying iluid pressure to the control system.

In the drawings:

Fig. l is a rear view of a motor vehicle having an aerial ladder extended in working position;

Fig. 2 is a side View of thevehicle illustrating the aerial ladder in its carrying position on the vehicle;

Fig. 3 is an enlarged rear view of the ladder mount;

Fig. 4 is `a side view of the ladder mount, illustrating a portion of the ladder and its elevating mechanism;

Fig. 5 is a sectional view taken along the lines 5-5 in Fig. 3;

Fig. 6 is a side View of the ladder mount illustrating an an embodiment utilizing a power take-olf fromY the vehicle drive;

Fig. 7 is a partial sectional View of the top of the ladder mou'nt taken along the line 7--7 in Fig. 6;

Fig. 8 is a partial sectional view of the nested ladder sections taken along lines 8 8 in Fig; 4 to illustrate the ladder extension mechanism;

Fig. 9 is a sectional view taken along the lines 9-9 in Fig; 8 to show the disposition of the ladder extension cables about the drum;

Fig. 10 is a side view of the forward end of the nested ladder;

Fig. 11 is la partial perspective view of a portion of United States Patent the ladder mount illustrating the mechanism operating levers;

Fig. l2 is a diagrammatic illustration of a uid pressure control system for operating the ladder;

Fig. 13 is a sectional view of the multiple plunger throttling valve for the control system of Fig. 12; and

Fig. 14 is a sectional View of -a check valve having an emergency release for the elevating portion of thecontrol system.

Referring now to Figs. 1 and 2 of the drawings, there is shown a motor vehicle having a truck body portion with an aerial ladder operatively supported in working position to provide access to some overhead object as in Fig. 1 or otherwise supported in carrying position as in Fig. 2. The ladder is of the extendable type comprising a pair of relatively movable ladder sections which coact in telescoping relation with each other in the customary manner and, for purposes of description, the lower section 12 will be referred to as the base ladder section and the extended section 13 will be. referred to as the fly section.

The base section 12 of the ladder is operatively supported on a column 15 which is optimumly located on the truck body 10 in such manner that the extensible ladder can be elevated in a vertical plane and the entire ladder assembly can be rotated on a vertical axis relative to the truck body. The column 15 is preferably tubular in form and projects upwardly from a pedestal base 16 that is rigidly secured to the foor of the truck body through a marginal flange 17. The column 15 rotatably supports a sleeve 18 which carries the ladder and a frame carriage 30.

The ladder mounting is shown in greater detailin Figs. 3 and 4 of the drawings as including upper and lower sleeve bearings 19 and 2t) for rotatably supporting the sleeve 18 on the column 15 and at the same time distributing the load stresses `along a considerable length of the column. The column has a circumferential groove 21 adjacent the top which receives a locking stud 22 carried by the sleeve 18 topermit locking the sleeve and its assembly in xed position onthe column. The upper end of the sleeve 18 carries a ladder supporting yoke 23 having spaced upwardly projecting arms 24 and 2.5 forming a trunnion cradle for receiving `a pivot shaft A26 whose extremities support the lower end of the base ladder section 12. This arrangement permits the ladder to Abe tilted in a vertical plane about its lower end in a manner to be hereinafter more fully described.

The frame carriage 30, which is carried by the rotatable sleeve 18 is constructed with side plates 31 and 32 separated by

transverse steps

33, 34 and 35 to provide access from the truck `body upwardly to the ladder at the top of the column. The carriage 30 has other supporting platforms upon which are mounted mechanisms for positioning the carriage and the ladder. In their preferred form, the positioning mechanisms are intended to be hydraulically actuated from a source of hydraulic pressure which, in the embodiment shown in Figs. 3 and 4 is integrally supported on the carriage frame and includes a reservoir 36 of hydraulic uid such as oil or the like and an engine driven pump 37 mounted on a platform 38. ln Fig. 3 the motive power takes the form of a combustion engine 40 which is also mounted on the platform 38 along with a fuel tank 41 and starting cable 42 and has its drive shaft 43 operatively coupled to the pump 37. The pump is connected between the reservoir land the various hydraulically operated mechanisms through suitable oil lines in accordance with the control ysystem to be hereinafter more fully described in conjunction with Figs. 12 through 14 of the drawings.

One positioning mechanism operates to rotate the sleeve 18 and its superstructure assembly on the column 15 and side rails of the ladder base section 12 (Fig. 8).

2,951,549 l Y f includes a conventional hydraulic motor 50 mounted on the platform 38. The motor 50 is intended to drive a wor-m shaft 51 through a sprocket arrangement including the sprocket belt 52 and the spaced

sprocket wheels

53 and 54. As best shown in the planular view of Fig. 5, the worm shaft 51 engages a worm gear 55 which is keyed or otherwise lixedly supported on the column 15 at the -lower extremity of the sleeve 18. Returning to Figs. 3 and 4, it is seen that the sleeve 18 has an annular liange 56 which coacts through the lower sleeve bearing 20 and against a thrust washer 57 supported on the worm gear 55 for rotation on the column 15 in response to driving Vengagement between the driven worm shaft 51 carried by the carriage 30 and the fixed worm gear 55. Since the carriage 30 and the ladder are each carried by the sleeve 18, they -will rotate with the sleeve whenever the motor t) is operated. p

`Another one of the positioning mechanisms is a hydraulically driven winch for extending the fly section 13 yof the ladder relative to the base ladder section 12. The winch takes the form of a cable drum 60 mounted on a shaft 61 suitably journalled in

end bearings

62 and 63 `carried by

side brackets

64 and 65 of the corresponding One extremity of the shaft 61 extends into a speed changing gear box 59 for driving engagement with a worm shaft 66 that is driven by another hydraulic motor 67, which, in turn, is powered by means of hydraulic iluid being supplied through suitable lines in the control system of Fig. 12. The extension hydraulic motor 67 and its speed changing mechanism are mounted on a platform portion 68 of the bracket 65 and are adapted to be tilted with the ladder for driving coaction with the cable drum 60 in any tilted position of the ladder.

The cable drum 60 carries a cable 69 that extends about a vcable sheave 70, which is rotatably mounted on the -ladder pivot shaft 26, and then loops about an upper pulley 71 (Fig. 10). The ends of the cable 69 are reversely wound about the cable drum 60 on either side of a separator 72 and then are secured to the ily section 13 to extend and retract the fly section relative to the base ladder section 12 in the customary manner whenever the extension motor 67 is operated.

An additional feature of this invention resides in the provision of a device for engaging and holding the ladder ily section 13 in fixed retracted position against the base section 12. This device takes the form of a pair of arms 73 each of which is ilxedly attached to one of the side rails of the lower ladder Section y12 and sloped in a forward direction so that they will engage the rear curved surface of -the fly section truss rod 75 when the y section 13 is in retracted position as shown at the top of Fig. 4. In its preferred form, each arm 73 is provided with a resilient pad 76 of rubber or the like which will wedge into semi-locking position against the curved rear portion of the fly section truss rod to prevent relative movement and rattling between the sections in their carrying position.

Referring again to Fig. 4 of the drawings, it will be seen that the platform 38 also has a bracket arm 79 which Vpivotally supports the lower extremity of a ladder elevating mechanism in spaced Vrelation froml the ladder pivot axis. The elevating mechanism includes a cylinder 80 having its lower closed extremity pivoted to the arm 79 and a piston 81 having its eX-ternalend pivotally coupled to a lever ar-m 82 on a cross member 83 extending between side brackets 64`and 65 carried by the base ladder section 12. The piston 81 is intended to be hydraulically positioned axially within the cylinder 80 by means `of hydraulic pressure to provide a lift for elevating the ladder about its pivot axis to any working position in a vertical plane. g

As hereinbefore noted, the hydraulically actuated mechanisms for rotating the ladder assembly about the supporting column and for extending and elevating the ladder are intended to be selectively actuated by means of the control system shown in Figs. 12 through 14. This system includes a multiple plunger throttling valve which has a central control block provided with

slide valve plungers

91, 92 `and. 93 that are movable within the control block to apply or remove hydraulic iluid from the pump 37 to the respective operating mechanisms in accordance with the operation desired. As best shown in Figs. 3 and 4 of the drawings, the control block 90 is positioned on an upper carriage platform extending forwardly from the top access step 35 and the plungers are provided with

operating levers

96, 97 and 98 which can be manually operated from the truck body 10. It will be noted that each of the operating levers has a pivotal connection to the corresponding valve plunger and has an apertured extremity projecting below such pivotal connection through slots in the access step 35 for rotation about a iixed bar 99.

One of the operating levers 98, corresponding to the actuation of the lift piston 81, has its upper extremity extending through a slot in a guide bracket 101 mounted on the carriage side plate 32 and includes mechanism intended to operate as a dead-man control. This arrangement is best shown in perspective in Fig. 1l of the `drawings where the guide bracket slot 100 is shown as having an enlarged central portion 102 for receiving the extremity 1013 of a spring biased locking sleeve 104. The sleeve extremity 103 has a greater dimension than the guide slot 100 and, when aligned with the enlarged portion 102, will be pressed into locking engagement therein by the spring 104. The locked position of the operating lever 98 corresponds to the neutral position of the corresponding valve plunger 93 and prevents any inadvertent operation of the lift piston 81 as will be hereinafter more fully described.

The embodiment, shown and described in Figs. 3 and 4 of the drawings, is provided with a self-contained source of power, such as the combustion engine 40, which is carried by the carriage 30 to drive the pump 37 and provide the necessary fluid pressure in the hydraulic control system. In this embodiment, the entire carriage assembly, including the power source and all the operating mechanism, rotates as a unit with the ladder and the sleeve 18 on the column 15 to provide an extremely flexible aerial l ladder which is easily controlled for rapid and accurate spotting of workmen and tools. In practice, the entire ladder assembly can be rotated through a full 360 sweep and elevated to an infinite number of tilted positions to a maximum limit determined by the lift piston extension. All of the movements, including the ladder extension, are hydraulically powered from a balanced support which serves the further purpose of housing the complete hydraulic system and power source.

In Figs. 6 and 7 of the drawings, there is shown an alternative arrangement where, instead of an integral power source such as a combustion engine mounted on the carriage assembly, the hydraulic control system is coupled to a suitable power take-off from the motor vehicle drive. As best shown in Fig. 6, the power takeoif includes hydraulic uid lines which extend centrally through the tubular column 15 from a pump 37A which is mounted on a bracket below the iloor of the truck body for driving coaction with a coupling to the take-off drive shaft 111.

Since the entire ladder mounting assembly, including the hydraulically actuated positioning mechanisms, rotate as a unit about the supporting column 15, it is necessary to provide a swivel iitting 1'12 for the fluid supply line `as shown in Fig. 7. With the power take-olf arrangement slrown in Fig. 6, the pedestal base 16 may be utilized as the hydraulic fluid reservoir with a suitable access fitting 114 and the return fluid line 121 can Vcommunicate with the reservoir in the base 16 through the tubular column 15 for rotation with the ladder mountlng assembly. g This arrangement permits full 360 rotation of the entire bladder mounting assembly without interference from hydraulic liuid lines `which are connected to |a remotely located pump coupled to the vehicle drive.

`Referring now to Figs. l2 and 13 of the drawings, there is diagrammatically shown in Fig. 12 a preferred hydraulic fluid control system `and in Fig. 13 a cross sectional View of the central control block 90 illustrating the manner in which the

slide valve plungers

91, 92 and 93` apply fluid pressure from the pump 37 to the respective hydraulically powered ladder positioning mechanisms. Referring particularly to Fig. 13, it is seen that the Valve plungers are intended to be axially positioned in the control block and are spring-biased at their inner extremity to maintain a neutral position. The block 90 is provided with an inlet 115 at one end and an outlet L16 Iat the other end connected by an irregular central passage 117 through the block which will permit fluid pressure to pass `when all of the Valve plungers are in a neutral position. The block includes access ports 122 through 127 paired on opposite sides of the central passage 117 for each plunger so that the ports of each pair can be alternately coupled to the lluid pressure in the central passage 117 or to the surrounding discharge passage 118. Such alternate coupling may be accomplished by counter-boring each of the valve plungers between axially spaced transverse apertures 130 which can be positioned to apply or remove Huid pressure from the access ports of the control block.

The operation of the valve plungers in the control block 90 will be more conveniently described in connection with the control system shown in Fig. 12 of the drawings which includes, in vaddition to the control block 90, the reservoir 36, the pump 37, the hydraulic rotation and

extension motors

50 and 67, the hydraulic lift S0, S1 and suitable control and check valves. The main shutoif valve 140 permits hydraulic fluid to pass from the reservoir 36 to the pump 37, which is driven by the engine 40 or bythe power take-off of Figs. 6 and 7, to apply fluid pressure to the supply line 120 and thence to the control block inlet 115. When each of the

valve plungers

9,1, 92 and 93 are in their neutral position, the central passage 117 `is open through the block 90 and the hydraulic fluid will ow through the block and the return line 121 to the reservoir 36 to complete the circulatory system. As best shown in Fig. 13, the control block 90 carries a relief valve 142 which operates to prevent the building up of excess uid pressure. Thus, for example, whenever the ow to any one of the hydraulic mechanisms is terminated, the excess pressure acting on the enlarged piston area will position the relief valve 142 against the spring bias 143 to by-pass the fluid from central passage 117 to the outer `discharge passage 118 for return to the reservoir 36.

The rotation motor 50 is coupled by

suitable lines

145, 146 to the paired access ports 122, `123 of the first valve plunger 91 which can be positioned to the left or right to apply hydraulic iluid pressure for rotating the motor in either direction, thereby causing rotation of the entire ladder mounting assembly in either direction on the supporting column 115. No `additional relief lines are necessary for the rotation drive, since it operates for a full 360. Of course, if the fluid operating pressure exceeds the maximum allowable pressure, the main relief valve 142 in the control block 90 would open and release such pressure to protect the rotation drive.

The hydraulic winch and ladder extension motor 67 is similarly coupled through

ylines

148, 149 to the paired -access ports of 124, 125 of the second valve plunger 92 and is protected on either side by

suitable check valves

150, 151 and a relief line 152 which includes a conventional relief valve 153 and check valve 154 establishing communication with the return line 121 to the reservoir 36. The relief valve 153 will be set for a predetermined safe release of the ladder when the load exceeds a safe limit.

The lift piston cylinder is coupled across the last valve plunger 93 through lines `155, 156 and flow control valve 157 and check valve 158. To elevate the ladder, the valve plunger 93 is positioned to the right to permit fluid pressure to be applied through access port 126 to the line leading to the flow control valve 157 and thence through the check valve 158 to the lift cylinder 80. The flow control valve 157 may be of any conventional type, while the check valve 158 is preferably of the type shown in Fig. 14 of the drawings. As hereinbefore noted in connection with Fig. 1l of the drawings, the lift operating lever 98 includes a dead-man control arrangement which automatically positions and locks the corresponding valve plunger 93 in a neutral position once the latter has been elevated to the desired angle. Retraction of the elevated ladder is -accomplished through the same path which elevated the ladder by moving the operating lever 98 to position the valve plunger 93 to the left. This places the lift cylinder inlet line 155 in communication with the return line 121 and, although the lift cylinder 80 is normally isolated from the return line 121 by check valve 158, the same position `of the valve plunger 93 applies fluid pressure through access port 127 and line 156 to the underside of the check valve piston 160 which operates against the ball-check 159' to open the return path for the Huid pressure in the lift cylinder 80. The lift piston 81 and ladder are then automatically retracted from their elevated position under the influence of the ladder load. The line 156 is preferably connected to the relief line 152 and the check valve 158 includes an emergency release for the ladder in the form of a hand-operated press-rod 163 which can be manually positioned to engage the piston 160 to open the ball check 159.

Thus, there has been provided an extremely exible aerial ladder having hydraulically powered movements which may be automatically controlled for rapid and -accurate spotting of workmen and tools. The hydraulic pump may be powered by an engine integral with the ladder mounting or by a truck mounted power take-olf to operate a rotation drive through an unlimited swing, to elevate the ladder through an infinite number of positions in its working range, and to drive a ladder extension winch. All of the movements are accomplished by operating a conveniently located multiple plunger throttling valve in a control system provided with pre-set relief lines 'and valves for safe operation.

We have shown and described what we consider to be the preferred embodiments of our invention, along with suggested 4modified forms, and it will be obvious to those skilled -in the art that other changes and modilications may be made without departing from the scope of our invention `as defined by the appended claim.

We claim:

An aerial ladder comprising `in combination, an extension ladder having a base section and telescoping ily section, a vertical column, a sleeve removably mounted on said column in encircling telescoped relation therewith `and adapted for rotation with respect to said column, means secured to t-he upper end of said sleeve supporting `a horizontal pivot shaft thereon, said shaft pivotally supporting the lower end of said ladder base section for tilting movement of the ladder in a vertical plane, a frame carriage mounted on said sleeve for rotation therewith, a iluid pressure actuated reciprocal type lift mechanism carried by said carriage and coacting between said carriage and the base ladder section to tilt the ladder in a vertical plane about said lower end, a iluid pressure actuated drive mechanism coacting between said oolumn and said sleeve for rotating said sleeve with respect to said column, said last mentioned drive mechanism including a gear xed to and circumscribing said column and disposed in separable meshing rel-ation with a drive gear carried by said carriage and movable therewith, said drive gear being .drivingly coupled to a reversible, rotary type fluid pressure .actuated motor .actuated winch mechanism carried by said ladder base section land coacting with the ladder ily section to extend or retract said i'ly section, said winch mechanism including 1a divided cable drum disposed beneath said ladder base section in parallel extending but longitudinally spaced relation to said pivot shaft, a reversible rotary type uid pressure actuated motor unit carried by said ladder base section, speed change means carried by said Iladder base section and operatively coupling said last mentioned motor unit to said drum for rotation of said drum in either direction, a pulley rotatably carried by said pivot shaft and a second pulley rotatably mounted at the outer `end of said ladder base section, a cable having each of its ends yoperatively secured to a respective one of the divided portions of said drum and being wound about said drum in a reverse direction with respect to one another, said cable extending about said pulleys and being operatively secured to said fly section whereby said ily section may be extended and retracted with respect to said ladder base section .upon actuation of said last mentioned motor unit in predetermined directions, a source of -uid pressure for operating said ladder lift mechanism, said drive mechanism and said winch mechanism, said source being completely carried by said sleeve Iand associated carriage for rotation therewith ,and including a reservoir for actuating lluid, an internal combustion motor power unit and a pump driven by said last mentioned power unit, manually operated control Avalve means mounted on said carriage and coupled to said pump for selectively controlling the -application of fluid pressure to each of said last mentioned mechanisms, and means for maintaining said sleeve and associated carriage and ladder in interlocked rela-tion with respect to said column and `against upward movement of said-sleeve with respect to ,said column, said last mentioned means comprising an axially movable stud member carried by said sleeve, said stud member extending transverse to the vertical axis of said column and .projecting into 1a circumferential groove in said column to vertically interlock said sleeve to said column, said stud member being retractable from said groove l:whereby said sleeve and associated carriage and ladder may be readily lifted upwardly as a unit from said column.

References Cited in the tile of this patent UNITED STATES PATENTS 139,689 Pine June 10, 1873 983,212 Dahill Ian. 31, 191-1 1,186,604 LHefureux Apr. 20, 1915 1,283,640 Blatzer -f-.. Nov. 5, 1918 2,238,665 Troche Apr. 1-5, 1941 2,614,743 Arps Oct. 21, 1952 2,635,430 Hodges Apr. Z1, 1953 2,654,524 Humpal et al. n n Oct. 6, 1953 2,663,150 Dolch i Dec. 22, 1953 2,742,216 Arps L; Apr. 17, 1956