DE2249927A1 - EXTENDABLE BOOM - Google Patents

Description

PATENT LAWYERS. 8902 Goggirgen near Augsburg on October 11th, 1972

von-Eichendorrf-Strasse 10

dr.ing. E. LiEBAU 2249927

_, _,, «, ^. / ~ I ICDAl I Our sign D 88 95

DIPL. ING. Previous year L-IClD AU (please specify in response)

Your sign

Del Mar Engineering Laboratories 6 901 Imperial Highway

Los Angeles, California / USA

Extendable boom

The invention relates to the construction of an extendable Boom that is used to move material and / or personnel to a desired one remote from the base part To bring point. The base part can, if necessary, be on a truck or similar mobile device are located and the boom can be used to carry out repairs on street lights or buildings, Carry out maintenance work on electrical and telecommunications equipment or carry out tree surgery etc .. ".

Extendable booms of this type have heretofore generally been equipped with telescoping pipe systems or had cantilever designs as described in U.S. Patent 3,470,981 or pending application Ser. No. 5 7,471 (July 23, 1970) der

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Applicant are described. Such extendable booms, with suitable drive and control devices provided and attached to mobile substructures, have long been used as lifting platforms, hoists, aircraft loading devices etc. have been used and were often built as pictorially in the cited publications shown; Scissor braces running parallel to each other were used, which were connected to each other by crossbars were connected in order to achieve synchronous movement of the scissor elements.

According to the usual designation for extendable booms a "field" consists of two pairs of supports (one pair of supports on each scissor brace) and each pair of supports is rotatably placed on top of one another in the middle of the carrier, so that two parallel scissor-like structures are created. Normally, the two scissor structures are arranged on opposite sides of the boom in such a way that that the inner beams of the structural elements are parallel to one another; the same applies to the outer carriers. at In practice, the two pivot points can be reached by a rod extending from one pivot point to the other be connected, whereby the two structural elements are held together. More fields are the boom added by placing the respective lower end of each such construction element at the respective upper end of the immediately construction element underneath is attached »Since each element works like a pair of scissors, If the lower ends of the beams are moved towards each other in the field at the very bottom, so will the upper ones Beam ends moved against each other. This effect is transmitted through all fields, whereby the boom in extended or extended in the direction in which it was rotated and raised. Each side of the boom forms thus a concertina gate that opens with the concertina gate

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the other side of the boom cooperates.

The known extendable booms work quite satisfactorily, if you have to bring people or equipment vertically upwards from the ground to working height. If the boom is raised at an angle to the horizontal, satisfactory results can also be achieved. However, it has been shown that as soon as the load on the work platform or in the basket is not arranged centrally so that it acted evenly on the concertina bars on both sides of the boom, or if so the truck chassis was not horizontal, certain to the side. Loads or forces acted on the boom and tried to squeeze one of the concertina bars while the other tended to get longer. The result this process is at least dangerous and possibly fatal for one at the far end of the boom working person because the boom tries to twist and can collapse because the twisted one Boom cannot withstand the load caused by the weight it lifts.

To ensure the joint movement of the two concertina bars and to prevent the boom from twisting, so far you have the internal beams of each field interconnected by torsion bars attached to the inner beams at or near both ends of the beams became. However, it has been shown that such torsion bars are not suitable, 'the inclination of a concertina gate to extend and the other concertina gate to collapse and the outer girders to leave to eliminate the alignment line if at the Aus senende an extended boom a relatively large

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Load was attached asymmetrically.

It was also found that the torsion bars attached between the inner beams of each field even become one even less desirable state - in addition to the occurrence of a certain twist. Applying a unbalanced load leading to the collapse of the concertina gate on the pressure side and can lead to expansion on the side of the boom exposed to tension, is carried out by the torsion bars, which exert torsional moments in every case, are balanced; the torsional moments, however, lead to the fact that the entire boom construction turns around its longitudinal axis turn looking. With a boom with only a few fields, this phenomenon is not very important because the angle of rotation communicated to the boom is quite small. As the number of fields increases, so does the boom rotation however, it closes quickly around its longitudinal axis, which reduces the exit length of the boom is limited. In the worst case, when extending a very long boom of this type in the case of asymmetrical loading, the person basket at the end of the boom rotates 180 ° around the boom axis turn, which of course has disastrous consequences.

Since such a concertina boom is relatively simple to be built and maintained, it would be very desirable To have a boom that can withstand unbalanced loads without twisting and becoming unstable.

The invention relates to a construction that can be applied to an extendable concertina arm, in order to prevent the boom from being around his when a load is placed asymmetrically on the boom arms Axis twisted. In particular, the invention relates to a construction that is used in such booms with the aim

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can be used to distribute an asymmetrical load between the cantilever arms or scissor bars uniformly so that equal within the fields and opposite moments are created, thereby eliminating their tendency to collapse or expand will. The goal can be achieved by reducing the induced torques, and the instability under certain circumstances Cause boom failure, be switched off.

In a preferred embodiment of the invention, the inner and outer beams are each Field connected to each other by torsion bars attached to the corresponding beams on the opposite side of the field are fortified "

The preferred embodiment of the device includes torsion bars that connect the external girders in each field of the two concertina structures, as well as similar torsion bars that serve to connect the internal beams. The ones on the outside girders attached torsion bars have a torsion spring force that is practically equal to that of the internal ones Support of each field connecting torsion bars is. Regardless of whether the bars are rigid or not, it is important that their spring action is practically the same. The invention is thus applicable to "rigid" and "non-rigid" torsion elements.

As a result, those in each field are from the torsion bars The torques generated by the external beams are the same as and opposite to those generated by the torsion bars of the internal ones Beams generated, eliminating unbalanced torques and rotation of the boom will·

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Another advantage of the invention is that you now have a single drive system for the extension the boom can get along; this drive is located in the middle between the two concertina structures and causes the extension and retraction of the boom »Since the extendable boom has become more stable in this way, a system can be provided with which lifting, Extending and rotating the boom around the base part is controlled independently, whereby the basket or the work » work platform must be precisely aligned at the end of the boom can.

You can thus use booms designed according to the invention, to move people and equipment at a much greater distance from the boom's supporting platform. Even more important is the fact that the people and / or equipment on the work platform or in the cage of the boom are secured to an extent that could not be reached with the known devices, because that Attaching an unbalanced load does not lead now more about twisting the boom, which could give rise to failure or an accident.

From the following description there is the further advantage that the torsion bars on the inner and external girders of successive fields as attached at a convenient, even distance · Ladder rungs can serve when a worker because of a functional error differently the basket on an extended boom could not leave.

Other features, advantages, forms and embodiments of the invention will become apparent to those skilled in the art without further ado.

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from the description below and the graphic Illustration of the preferred embodiment of the invention. The drawings show:

Fig, I is a perspective view of an extendable Boom according to the invention, the boom being mounted on and facing a truck is brought into an extended position;

FIG. 2 is a perspective view of a section of the boom shown in FIG. 1 on a larger scale with more details of the control of the boom;

Figure 3 is an isometric view of four fields of one such an extendable boom in a partially extended position;

4 shows a sectional view of a field of an inventive Boom, sectioned on the line IV-IV in Fig. 3; '

FIG. 5 shows a similar sectional view as in FIG. 4, but in section on the line V-V in Figure 3;

6 shows a side view of two fields of a boom according to FIG. 1 in the collapsed state.

According to * FIG. 1, a base part 13 is on a vehicle 11 arranged on which a total of 15 designated extendable boom is located. In the special representation 1 shows the boom 15 two concertina grids, in the present case with seven fields, of which

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each consists of two carrier groups 17 and 19. Each carrier group 17 contains an external carrier 21 and an inner carrier 23, while each carrier group 19 has an outer carrier 25 and an inner Has carrier 27. The inside beams 2 3 and run parallel to one another, likewise the outer supports 21 and 25 are parallel to one another. Two at a time opposing carrier groups 17 and 19 thus form a field, and if a number of fields in the manner of In Fig. 1 drawn arrangement are assembled, as the drawing clearly shows, on each side the boom formed a concertina gate.

At the outer end of the boom is at the ends of a pair of parallel end beams 31, which from the seventh Go out (last) field and hold a basket or work platform 29 suspended. When using the boom the basket 29 hangs vertically downwards from the supports 31 under the action of gravity. If necessary, can a control panel 33 can be attached to the basket, from which the worker located in the basket can determine the position of the Basket can affect; a similar control panel, not shown, can be attached to the truck 11.

1 and 2 show particularly clearly that the base part 13 carries a platform 37 on which a drive 39 for the elevation angle, an extension drive Ul and a rotary drive 4 3 are provided. If necessary, a battery pack 19 can also be accommodated on the platform 37 that can feed the drives 39, m and 4 3 for elevation, extension and rotation.

The drive 3 9 for the elevation and the extension drive 41 can be used as independent screw jacks or hydraulic

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Lische lifting devices be formed, but they can if necessary to be confirmed individually so that the boom can be controlled better. As rotary drive 43 For example, an electric motor can serve as a pinion 45 drives; when the motor is fixedly attached to the platform 37, the pinion meshes with one on the base part 13 attached ring gear 47 to set the platform and thus the boom in rotation. Regardless of the type of the drive for the rotary movement of the boom but this drive can also be operated by itself to control the control to improve the boom.

The drive 39 for the survey is connected at one end to a cross member 51 between perpendicularly crossing Guide rail pairs 5 3 and 55 is attached. The guide rails are on the platform 37 in the pivot points 5 9 and 61 pivotally mounted so that when actuated of the drive 3 9 for the elevation of the force exerted on the cross member 51 up the guide rail pairs 5 3 and 55 can pivot. Fig. 1 shows the guide rails in a central position, which is after the start of actuation of the Elevation drive adjusts. In Fig. 2, however, the pairs of guide rails are approximately ver = by the drive 39 tically directed. Of course, the drive 39 also controls the lowering of the boom, which, for example, comes in handy horizontal position can be lowered.

A comparison of FIGS. 1 and 2 with one another also shows that, as mentioned, the rotary drive 43 can be used for itself can, for example, by a switching element on the control panel 33 or one provided on the floor, which has the same effect Switching element is actuated to bring the platform 37 in any desired direction and thus also the boom

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to turn in that direction.

In Fig. 2 it is also drawn that the carrier on the opposite sides of the first field through centrally arranged bolt 63 are connected to one another. The extension drive 41 engages in the middle of the bolt 63 » and the bolt is with its ends in bearings in the inner beams 23 and 27 and the outer ones Supports 21 and 25 added. Since the bolt 6 3 is connected to all beams of this field by bearing points, the bolt is triggered when it is triggered by the extension drive 41 will not strive to rotate relative to the drive 41, but will be the pivot point on both Push the sides of the field up. That has because of the The method of operation of the device to be described below means that the upper ends of the inner like the outer carrier on both sides of the field to move towards each other like scissors. Of course leads this to the fact that the boom is extended because the lower ends of the rotatable carrier group in the second field are brought together and in turn the upper ends of the rotatable carrier in the second field towards one another move. A comparison of FIG. 2 with FIG. 6 clearly shows that the boom is extended in this way, so that the extended state shown in FIG. 1 results.

The pivot connection point of the bolt 63 with the beams on both sides of the first field and thus the pivot connection point of the two carriers are movable with the aid of rollers 71, which from the pivot points on both Sides of the field protrude. The rollers 71 cooperate with the parts of the rails 5 3 and 55, which in the Axial direction of the boom run. The rollers 71 can therefore shift in the axial direction, but in

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no other level.

On the other hand, the lower ends of the four girders of the deepest field are provided with rollers 73 which cooperate with those sections of the rails 5 3 and 55 which are perpendicular to the axial extension direction of the boom. In other words, the rollers 73 can move freely in a direction perpendicular to the extension axis of the boom, but are unable to move in any other plane relative to it. The movement of the different sections of the first field of the boom when driven by the Aus drive inr ich do g ¹ II is strictly limited to paths in predetermined planes. The movement of every other carrier field is correspondingly limited, because the movement of each field is precisely controlled by the movement of the field immediately below it «

Fig. 2 shows that the outer beams 21 and 25 of the first field by one at the lower beam ends attached torsion bar 75 are connected. According to Fig. 1, the lower ends of the inner carrier of the first field connected to one another in a corresponding manner by a torsion bar 77 arranged between them.

The torsion bars 75 and 77 are like the other torsion bars described below on the opposite one another Brackets attached to maintain the spacing between the brackets, similar movement of opposite one another To ensure support in each field and the forces exerted on each field in its support evenly to distribute. Near the upper ends of the girders of the first field, the outer girders are again through

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a torsion bar 79 and the internal beams connected by a torsion bar 81. The rotating bars 75, 77, 7 9 and 81 thus strengthen the first field and distribute the moments in it.

As can be seen in FIG. 2 for the second field, two torsion bars 83 and 85 connect the internal beams 23 and 27, while a second group of torsion bars 87 and 89 connect the outer beams together. In other words: the outer beams in each field, starting with the second field, are for the specified one Purpose linked in the manner shown. Each staff thus ensures maintenance of the distance between the girders of the two concertina arms and distributed in the manner indicated above to the Fields acting torques in practically equal proportions.

It should be remembered that in the known devices only the internal supports of each field are attached to their upper and lower ends are connected to each other, while there was no connection between the outer beams. The invention thus represents a system in which forces and moments are distributed so that a rotation of the boom around its axis cannot occur.

This can be seen clearly from Figs. 3 to 5, if for example Lateral loads A act on the outer end of the girder, for example through asymmetrical loading the working platform or the basket 29 or by the action of gravity on the basket in non-horizontal Position parked vehicle 11, a reaction force B a? Is generated at the lower end of the boom. The forces A and B thus exert a torque on the boom that

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must be compensated by the forces C and D. Fig. 3 shows clearly that the forces C the concertina arrangement, consisting of the carrier arrangement 17, to be pressed together and at the same time trying to stretch the concertina arrangement consisting of the carrier group 19. In other words: the internal beams in each group 17 try to rotate in the opposite direction Clockwise, the inner beams in group 19 simultaneously rotate clockwise (the directions each related to the figures). These tendencies of rotation are shown in FIGS. 4 and 5 by the arrows E and F indicated.

Since the inner beams are connected to each other by the torsion bars 8 3 and 85, whereby their rotation in opposite directions are avoided, a torque G, clockwise, i.e. opposite to the Rotational tendency of the carrier, acting, introduced on each internal carrier of the assembly 17 and the same and opposing torque R is applied to the interior girders of each bay in the concertina structure 19 introduced. That in the seer arrangement 17 acting torque G deflects this arrangement in the direction indicated by the arrow J, while at the same time the torque H acts on the arrangement 19 in order to deflect it in the direction indicated by the arrow K. Therefore, taking into account the direction of the arrows J and K in FIG. 3, it follows that the entire boom extension strives to rotate around its central axis Z in the counterclockwise direction (seen from above) to twist.

This is the situation that exists with the known constructions. In other words: the ones inside

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Torsion bars connecting girders prevent one concertina from stretching while the other contracts, but as a result causes the entire boom to rotate about its axis, creating a dangerous Situation arises, which should now be understandable because of the force analysis provided above.

Under the load conditions described above, the outer girders 21 of the concertina gate 17 are looking for one Clockwise rotation (arrow L in Fig. 5) and the outer carrier 25 of the concertina gate 19 seek to produce a counterclockwise rotation (arrow M in FIG. 4). These tendencies to rotational movements can be counteracted by the torsion bars 87 and 89, which generate a torque N (Fig. 5) that in the direction acts counterclockwise on the carrier 21, and a torque P (Fig. H), the clockwise on the Carrier 25 acts.

If the torsion bars 83, 85, 87 and 89 are chosen so that their torsional spring forces are equal and the sum the torsion spring force of any pair of torsion bars connecting the internal girders is equal to the sum of the Is the torsional spring force of any pair of torsion bars that connects the associated pair of external beams, the twist of the overall arrangement is canceled. With In other words: with the same spring forces, the torques introduced by the rods 8 3 and 85 are the same and opposite to the torques introduced by the rods 87 and 8 9. As a result, the torques are on the entire carrier assembly is balanced and any tendency of the assembly to rotate about an axis is eliminated. In other words: the torque indicated by the arrow Z in FIG. 3 is precisely compensated by

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a torque that is exactly the same as that indicated by the arrow but acts in the opposite direction.

Another advantage of the invention is that the Use of the torsion bars connecting the inner and outer beams of each field is a satisfactory one Allow use of the simple Aus Sir drive 41, to extend both concertina gates of the boom because the torsion bars 83, 85, 87 and 89 enable the scissor bars to to resist the forces C and D, so that equal forces at the ends of the bolt 63 with respect to its center point, on which the extension drive 41 acts, are balanced. This naturally increases the weight and reduced the cost of the whole facility. In other words, the invention provides a construction with which the possible twisting of the boom with asymmetrical loading can be avoided, by using rigid components as a connection between the external girders of the two scissor bars are, the rigid components are comparable in their rigidity with similar components that the inner carrier of the scissor lattice texle with each other associate. As a result, equal and oppositely directed torques in each field become more unsymmetrical in the case Stress generated, thereby avoiding the occurrence of unbalanced torques within each field.

Another advantage of the invention is the possibility that a person in the basket is at significantly extended boom in the event that a malfunction occurs, climb down from the boom by using the torsion bars of each field as a ladder rungs and thus the safety of their own person-

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considerably enlarged.

The invention thus shows a novel and advanced embodiment of an extendable boom; the progress is expressed through an increase in operational safety and the elimination of the possibility of a malfunction or damage to the system.

Patent claims :

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Claims (1)

Claims 1 »Extendable boom with two parallel to each other Concertina bars, characterized by a number of fields with two in parallel outer supports (21, 25) extending to one another, two inner ones extending parallel to one another Carriers (23, 27), by a pivot bearing, each of which has an external and an internal carrier each of the two field sides connects and through at least one of the internal beams (23, 27) and through at least one of the external supports (21, 25) rigidly connecting to one another and transmitting torsional forces Furnishings. 2. Boom according to claim 1, by a along the axis of the boom (15) acting means (41) which The concertina gate extends or retracts. 3 »Boom according to claim 1, characterized by a mount that serves as a holder for the boom _t as well as independently operated drives for the elevation (39), the turning (H3) and the extension ( ¹ H) of the boom« 4 * device to avoid twisting one out two scissor bars existing retractable release vessels§ 309816/0880 characterized by at least one between the inner ones Supports (23, 27) of each field of the boom and at least one between the outer ones Supports (21, 25) of each field of the boom (15) running, torsional forces transmitting device * 5. Device according to claim 4, characterized in that at least one of the torsion forces transmitting devices, which connects the internal beams (23, 27) and at least one of the torsion forces transmitting devices, which connects the external beams (2125), are designed so that their torsion spring forces are practically the same. 6 _t device according to claim 1, characterized »by a supporting element, by a guide element attached to the supporting element and by a movement limiting device which is arranged on the lower section of the boom and accommodated in the guide element for joint action. 7. Device according to claim 6, characterized by a drive device mounted on the support element for the extension of the boom as well as by rotating aids attached to the boom within the lowest Field and in operative connection with the drive for extending the boom to move the movement limiting device inside the guide element when the drive for extending the boom is retracted 309816/0880 is switched. Device according to Claim 4, characterized by a support element, one arranged on the support element Movement drive for the boom and through to that Auxiliary devices attached to the support element to control the movement of the lowest section of the boom when the boom is extended by the drive mechanism * Extendable boom, characterized by a support element, two parallel to each other, on the support element attached concertina gate with an internal beam and an external beam in each section of the boom and by means of a device that prevents the boom from rotating about its center line passing through it, which device auxiliary devices for the transmission of torsional forces between the 'inner Supports for each field of the boom as well as auxiliary devices for transmitting rotational forces between the outer ones Has supports each field of the boom. 10. Boom according to claim 9, characterized in that the support element consists of a platform (37), one pivotable on the platform (37) attached rigid guide (53, 55) and one on the lower span of the boom (15) attached device that is in the rigid guide (5 3, 55) reaches in, looks at it. 309816/0880 11. Boom according to claim 9, characterized by a means (43, 45, 47) arranged on the platform (37) for independently changing the rotational position of the boom (15) relative to the platform (37). 12, boom according to claim 9, characterized by a device (39) arranged on the platform (37) for independent change of the elevation angle of the boom (15) opposite the platform (37). 13. Boom according to claim 9, characterized by a Device (11) arranged on the platform (37) for the independent extension and retraction of the boom. 14, boom according to claim 13, characterized in that the extension and retraction device consists of a single drive (41) and a device that the exerts the force supplied by the individual drive along the center line extending through the boom. 15, extendable boom, characterized by two concertina bars, each of which has a number of internal supports (23, 27), a number of external supports (21, 25), a first pivot bearing that has an internal support connects with an external carrier in the middle, and has a second pivot bearing that each internal beam connects to at least one external beam at their ends and an 3098 16/0880 - 21 - 224B927 direction that has a parallel and equal movement of the two concertina bars and from one first, moment-transmitting device between opposing inner beams and one located on one of the concertina gates second, torque-transmitting device between opposite one of the concertina gates external girders located " 16, boom according to claim 15, characterized in that the first and the second torque-transmitting device consist of rigid rods (83, 85, 87, 89) which are attached to the associated carriers are attached and are located between the first and the second pivot bearing. 303816/0880 Blank page