Description:
BACKGROUND OF THE INVENTION
The present invention relates to aerial platforms for supporting workmen at positions remote from a supporting vehicle.
Aerial platform apparatus has come into wide-spread use for supporting workmen at positions remote from the ground, usually at a position elevated substantially above ground level. Such apparatus have conventionally included a motor vehicle on which is mounted an extensible boom, the boom being rotatable about a vertical axis, and pivotable about a horizontal axis for luffing movement. Suitable power means were provided for effecting the rotational and luffing movements of the boom, as well as the extension and retraction of the boom, hydraulic cylinders being preferred for the boom luffing and extension movements. The operations of the boom, to thereby effect movement of the workmen in the platform, could be effected both from the platform, and at ground level. The platforms were provided with a floor, and upstanding walls in order to provide safety for the workmen carried on the platform.
The prior art contains a number of proposals with regard to improvements on the basic aerial platform apparatus as described hereinabove. Thus, a number of proposals have been made for moving the work platform in a horizontal plane relative to the end of the boom. In one such proposal, a pair of platforms were mounted on opposite sides of the boom at the outer end thereof, and each platform could be moved through a substantial arc, in the case of one platform through an arc of substantially 90°, while in the case of the other platform, movement could be effected up to about 135°. With regard to this latter, side-mounted platform, it could move between a position at the front of or forwardly of the boom, in an arc towards the rear of the noted substantially 135°. However, in this construction, it was not possible to move one platform from a position on one side of the boom to a position on the other side of the boom.
In another construction, intended primarily for use as a crane in an orchard, the platform was mounted on a pivot lying forwardly of the end of the boom, which was non-extensible, and rotation of the platform relative to the boom was effected through an arc of approximately 90° by means of a hydraulic cylinder operating a cable trained over pulleys.
In another proposal of the prior art, intended primarily for use in picking fruit, the boom was provided with a pair of platforms mounted on vertical pivots, and capable of motion through approximately 45°, movement being effected by a crank provided on the platform for operating a gear system.
In another proposal intended for use primarily in connection with providing a support for a workman splicing cables, the platform was carried by an L-shaped arm or bracket having a horizontal arm underlying the workman's platform, and a vertical arm extending upwardly therefrom and being connected to a pivot pin extending horizontally to one side of the boom, and connected to a fitting at the end of the boom. In this construction, the basket could rotate through 180°, at one side of the boom.
In addition, there has been provided overhead maintenance apparatus providing a vertical column on which was mounted a platform rotatable about the axis of the column, or about an axis parallel to and to one side of the column, but in such construction, there was no boom which was capable of luffing motion.
All of the above prior art constructions, while providing some flexibility for the positioning of the platform and the workmen thereon, were nevertheless somewhat deficient in the degree of flexibility provided for the positioning of the platform and the workmen. This was particularly true where certain operations were to be performed. For example, it is now known to be desirable to utilize aerial platform apparatus for supporting workmen to perform work along the length of a structure, such as a building, of a substantial distance. Such work includes painting the side of a building, or even the installation of exterior wall panels, which may be provided in conventional size, such as four feet by eight feet. The prior art constructions of aerial platform apparatus were not suitable for such work, unless there was an undesirably large amount of movement of the vehicle, in order that the platform and the workmen carried thereby be placed in different operative positions relative to the building or other structure being worked on.
SUMMARY OF THE INVENTION
The aerial platform of the present invention includes a vehicle having an extensible boom mounted thereon for swinging movement in vertical and horizontal planes, at the free end of the boom fly section there being a connector which is pivoted at the end of the fly section on a horizontal pivot. The connector at its outer end is in the form of a semi-cylindrical housing having a vertical axis. A rotary hydraulic motor is carried in the housing, having a part fixed to the housing and a second part rotational relative to the first part extending above the housing, with a platform support structure attached to the latter part of the rotary motor. A shaft extends downwardly from the bottom of the housing, coaxial with the axis of the rotary motor, and a bracket arm extends from the support and is journalled on this shaft. The platform is carried by the support, and includes a floor which is of rectangular plan form. The support and platform may be rotated through substantially 180°, by the rotary motor, from extreme positions of the platform which are at either side of the boom. In the central or neutral position, the mid-point of one long side of the platform is forwardly or outwardly of the axis of the rotary motor, and is, like the axis of the rotary motor, on an extension of the boom longitudinal axis. The diameter of the semi-cylindrical housing is at least as great as the width of the connector. Movement of the connector in a vertical plane about its pivot causes similar movement of the platform, to thereby maintain the floor of the platform horizontal during luffing movement of the boom, this being accomplished by master and slave cylinders which effect simultaneous, equal and opposite movement of the connector as the boom is luffed.
Among the objects of the present invention are to provide an aerial platform apparatus having greater flexibility of the workman-supporting platform. A further object of the present invention is the provision of an aerial platform apparatus which provides a greater operating range for the platform and the workmen thereon, without movement of the vehicle.
Yet another object of the present invention is provide an aerial platform apparatus of greater flexibility, which is of strong construction, while being economical, and not requiring either unusual materials or construction techniques.
Other objects and many of the attendant advantages of the present invention will be clearly understood from the following specification and claims, and the drawings appended hereto and forming a part hereof.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a plan view of an aerial platform apparatus in accordance with the present invention.
FIG. 2 is an elevational view, with parts broken away, of a portion of the apparatus shown in FIG. 1.
FIG. 3 is a cross-sectional view taken on the line 3--3 of FIG. 2.
FIG. 4 is an enlarged elevational view of a portion of the structure shown in FIG. 2.
FIG. 5 is a plan view of the end portion of the boom and platform of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, wherein like or corresponding reference numerals are used for like or corresponding parts throughout the several views, there is shown in FIG. 1 an aerial platform apparatus generally designated 10, and including a wheeled vehicle 12 of conventional engine-powered and steerable construction. The vehicle 12 includes outriggers 14, one of which is shown in FIG. 1, and gearing 15, shown schematically and of conventional construction, for rotating a boom 20 about a vertical axis. At its outer end, the boom 20 carries a workman-supporting platform 60. As shown in FIG. 1, the boom 20 may be rotated about a vertical axis, and may also be extended and retracted, so as to position the platform 60 at different places along a wall W. In the example herein illustrated, the wall W is a part of a building under construction, and it is necessary for the workmen to perform various tasks on the wall, or in connection with the construction of the wall, such as painting it or applying panels of wall-forming material to a basic structure. As is generally indicated by the showing in FIG. 1, the platform 60 may occupy a position somewhat forwardly of the front of the vehicle 12, wherein one side of the platform is closely adjacent one side of the boom 20, to an opposite position wherein that side of the platform is adjacent the opposite side of the boom 20. As will be understood, in some instances it may be possible to position the vehicle 12 closer to the wall W, and in that instance a greater range of positions of the platform 60 along the wall W can be effected.
Referring now to FIG. 2, there is shown a base 16 which is rotatable about a vertical axis, as by the aforementioned gearing system 15. Extending upwardly from this base is a boom support 18, typically in the form of a pair of spaced apart, generally vertically extending plates having between them a boom luffing cylinder 19 which is operated by hydraulic fluid from a suitable pump in conventional manner to raise and lower the boom 20. At its upper rear end, the boom support 18 has pivotally connected to it about a horizontal pivot the boom 20 which is an extensible boom of known configuration, and having three telescopic sections 20 A, 20 B and 20 C. Telescopic movement of the sections relative to each other is effected by suitable power means, such as hydraulic cylinders, not shown. A support generally designated 22 is secured to the end of the fly section 20 C, and a horizontal pivot pin 23 pivotally connects a connector 30 to the support 22, and hence to the boom 20. The connector 30 carries a rotary hydraulic motor generally designated 40, to which is connected a platform support structure 50, which latter carries the platform 60.
In order to maintain the platform 60 level during luffing movement of the boom 20, the boom 20 is provided at its rear with an ear 24 to which is connected the piston rod of a master cylinder 25, having the cylinder itself pivotally connected to the boom support 18. The aforementioned support 22 has a portion thereof extending above the boom 20, to carry a slave cylinder 26. Hydraulic lines L-1 and L-2 interconnect the master cylinder 25 and the slave cylinder 26, so that as the boom luffing cylinder 19 raises the boom, the master cylinder 25 will be actuated, and will in turn actuate the slave cylinder 26, to impart simulatneous, equal and opposite rotational movement of the connector 30 about the pivot pin 23, relative to the rotational movement of the boom 20 about its pivotal connection with the boom support 18.
As may be seen in FIGS. 2 and 3, the support 22 at the end of the fly section 20 C is in the form of a pair of spaced plates 22A and 22B, parallel to each other, and lying in vertical planes. The pivot pin 23 passes through the plates 22A and 22B forming the support 22, and also through plates 31 and 32 forming parts of the connector 30. The plates 31 and 32 are in vertical planes, and lie inwardly of the plates 22A and 22B of the support 22. At the right hand or forward end, the connector 30 terminates in a housing 33 which has a vertical axis, and which is in the form of a cylinder, although a completely cylindrical housing is not required and is shown herein as being utilized for purposes of strength. In practice, a semi-cylindrical housing could be utilized. The plates 31 and 32 are joined to the housing 33, and a plate 34 (see also FIG. 4) lies along the top surfaces of the plates 31 and 32, plate 34 terminating in a semi-cylindrical formation, or flange 34A having a slightly greater radius than that of the housing 33. A flange 41 of the motor 40 overlies the plate 34, and bolts 42 secure the motor 40, through flange 41, to the plate 34, and hence to the connector 30. As will be seen, the diameter of the structure including the housing 33 and the flange 34A of plate 34 is at least as large as the width of the connector 30, as determined by the spacing of the plates 31 and 32, to thereby permit full 180° rotation of the platform 60, from one side of the boom and connector 30 to the other side thereof.
Referring now to FIGS. 2 and 4, a platform support structure 50 is provided, which is generally in the form of a hollow, somewhat pyramidal housing including spaced side plates 51 and 52, the latter of which is shown broken away in FIG. 4, an inclined rear plate 53 and a front plate 54. A horizontal plate 55 extends between the aforesaid plates forming the pyramidal platform support structure 50, and is provided with opening in which is positioned the rotary fluid motor 40. The motor 40 is provided with a second flange 43 which underlies the plate 55, and is secured to it by an annular series of bolts 44. The flange 43 is rotational relative to the flange 41, so that when fluid is supplied to the rotary motor 40, the upper part thereof, including the flange 43, will rotate about the axis of the motor 40, which is coincident with the housing 33, while the part of the motor 40 to which the flange 41 is connected remains stationary. It will thus be seen that the rotary motor 40 provides power for rotating the platform 60. As will be seen in FIGS. 3 and 4, the left hand portion of the housing 33 is provided with an opening 35 through which pass hydraulic lines L-3 and L-4 for supplying hydraulic fluid to the motor 40, which is of known construction. As will be understood, the controls for the motor 40 are provided on the platform 60, and duplicate controls may also be provided at ground level.
The platform support 50 will be seen to have the side plates 51 and 52 thereof terminate at a level somewhat below the horizontal plate 55, and above the flange 41, except for portions of these plates lying adjacent to the front plate 54, which portion is designated 52A in FIG. 4 and which may be seen to extend downwardly to a point below the bottom of the connector 30. A bracket 56 extends rearwardly from the lower portion of the platform support 50, being journalled on a shaft 36 which is coaxial with the motor 40. The shaft 36 is carried by a lower plate 37 of the connector 30 and by an annular plate 38 which is secured to the plate 37 by fasteners 39.
Referring again to FIG. 2, it may be seen that the platform support 50 has the platform 60 secured thereto at connecting points 57A and 57B, which may take the form of bolts or the like. Mounted within the platform support structure 50, and accessible to workmen on the platform 60 are the aforementioned controls, designated 59, for control of the platform, including the boom, by the workmen on the platform 60.
Referring now to FIG. 5, there may be seen the support 22 including the spaced plates 22A and 22B, with the slave cylinder 26 therebetween, having the piston rod 26A thereof pivotally connected to a pivot pin 27 secured in the connector 30, which apparatus serves to transfer motion from the slave cylinder 26 to the connector 30, for maintaining the platform 60 level. The plate 34 at the upper part of the connector 30 may be seen, we well as the platform support structure 50. As is clearly shown in FIG. 5, the platform 60 is preferably of rectangular plan form, and in the central or neutral position shown in full lines in FIG. 5, the platform support 50 is connected to the mid-portion of a long side of the rectangular platform 60 and an axis of the platform is in line with the axis of the boom 20. Preferably, the length of the platform is something over 8 feet, so as to accommodate certain building materials which have a length of 8 feet, on the platform. As is further shown in FIG. 5, the platform 60 may be moved between two extreme positions relative to the boom 20, one position having a side of the platform adjacent the left side of the boom 20, and substantially parallel thereto, and the other position being substantially adjacent the right side of the boom 20, and substantially parallel thereto. Thus, the axis of the platform, referred to above, will be substantially perpendicular to the axis of boom 20 in the two positions shown in phantom lines in FIG. 5. It will be appreciated, however, that with the construction shown, slightly more than 180° of rotation in the horizontal plane, about the axis of the motor 40, may be accomplished. As will be appreciated, the axis of rotation of the platform 60 is external of the platform, being the axis of the rotary hydraulic motor 40, and shaft 36.
In use, equipment to be used by the workmen may be placed on the platform, and the workmen may then board the platform, after the vehicle 12 has been positioned adjacent the location of the work, such as the wall W in FIG. 1. Assuming that the task to be performed is the placing of facing panels on an exterior wall, the vehicle 12 will have been maneuvered as close as possible to the wall W, and with a number of panels carried on the platform 60, the initial positioning of the platform 60 may be such that it lies substantially adjacent the right side of the boom 20. As panels are assembled onto the building structure, the boom 20 and platform 60 are moved, but not the vehicle 12, until a position is reached where the platform 60 is substantially adjacent the left side of the boom 20. In that event, relative to the boom 20, the platform will have moved through substantially 180°, from one side of the boom 20 to the other side thereof, while at all times the workmen on the platform 60 will have been in position to perform their work of assembling the facing panels to the building.
The aerial platform apparatus herein disclosed provides great flexibility for positioning of an aerial platform relative to the work, or to a structure on which work is to be performed. Further, the apparatus herein disclosed provides for the maintenance of the work platform in level condition, no matter what is the angle of inclination of the boom. The construction herein disclosed is strong, yet is economical and does not require any special materials or assembly techniques.
It will be obvious to those skilled in the art that various changes may be made without departing from the spirit of the invention and therefore the invention is not limited to what is shown in the drawings and described in the specification but only as indicated in the appended claims.