EP1672126B1

EP1672126B1 - Pinned boom for earth moving machines equipped with a hydraulic apparatus for the insertion and for the extraction of junction pins.

Info

Publication number: EP1672126B1
Application number: EP05020075A
Authority: EP
Inventors: Gabriele Rossetti
Original assignee: PMI Padana Macchine Industriali SpA
Current assignee: Volvo Construction Equipment AB
Priority date: 2004-12-14
Filing date: 2005-09-15
Publication date: 2009-12-30
Anticipated expiration: 2025-09-15
Also published as: ATE453761T1; EP1672126A3; ITPR20040090A1; DE602005018593D1; EP1672126A2

Abstract

A hydraulic apparatus for the insertion/extraction of pins on pinned booms of earth moving machines comprises at least one hydraulic cylinder (4) whose rod (5) is operatively connected with at least one pin (3) to be inserted/extracted in order to associate/disassociate a base boom (1) of the machine with respect to a second boom (2) or accessory boom. Said at least one hydraulic cylinder (4) is applied internally and not in overhang on the pinned base boom (1) or on a part of the machine.

Description

The present invention relates to a pinned boom for an earth moving machine, such as hydraulic excavators, with the aim of rendering rapid, safe and economical the use of pinned booms by an operator for coupling various equipment items, in particular for coupling a base boom comprised in the machine with excavation booms or demolition booms, or other types of booms, all of these booms being of pinned type.
According to a first technique known in the prior art, the pins are inserted/extracted manually, with enormous time expenditure and considerable personnel costs. The operator must be assisted by another person throughout the operation, which requires a sizeable physical effort in the presence of an injury hazard, in consideration of the weight of the pins to be handled and of the force needed for their insertion/extraction.
According to a second technique known in the prior art, hydraulic cylinders are used to insert/extract the pins, according to two different procedures.
One procedure provides for a mechanical joint and a single pinning, which is achieved by means of two opposite cylinders, positioned externally to the boom and with the rods serving as a pin.
In addition to having a considerable bulk, this forces the cylinders to work in overhang, with very high stresses and with a tendency to acquire play, with the consequent rapid wear and the (costly) need to replace both cylinders, and not a simple, economical pin.
A second procedure provides for using a cylinder which actuates two half-pins by means of leverage mechanisms, but in this case too the cylinder with the pins work in overhang with the same problems as the first procedures.
FR 2 340 466 discloses a pinned boom, wherein a single cylinder is arranged to operate two co-axially arranged half-pins. The cylinder and the half-pins are arranged internally in the boom. More specifically, the half-pins are movable relative to one another in opposite directions between a first state, in which they are at a small distance from each other for disconnection of the boom parts, and in a second state, in which they are at a larger distance from each other for connection of the boom parts.
EP 0 615 023 discloses a pinned boom, wherein two half-pins are co-axially arranged internally in the boom. The half-pins are movable relative to one another in opposite directions via a hydraulic cylinder function between a first state, in which they are at a small distance from each other for disconnection of the boom parts, and in a second state, in which they are at a larger distance from each other for connection of the boom parts.
An object of the present invention is to eliminate the aforesaid drawbacks making available a pinned boom adapted for insertion and extraction of pins, which is safer and more economical and which allow a longer duration of the hydraulic cylinders.
Said object is achieved by the pinned boom according to claim 1.
This and other characteristics shall become more readily apparent from the following description of a preferred embodiment, illustrated purely by way of non limiting example in the accompanying drawings in which:

Figures 1 and 2 show a lateral view of the apparatus with the boom in two different operative positions;
Figures 3 and 4 show the cylinder in a cross section A-A of Figure 2 at a pin, respectively in condition of inserted pin and of extracted pin;
Figure 5 shows a perspective view of a detail of the apparatus with the pin extracted from the boom.

With reference to the figures, the reference number 1 schematically designates a base boom mounted on an earth moving machine, such as an excavator.
To the base boom 1 is associated, in the illustrated example, a pinned excavation boom 2 with two positions (straight as in Figure 1 or bent as in Figure 2), which, however, can be any boom or pinned equipment able to be associated to the base boom 1.
The association between the excavation boom 2 and the base boom 1 is accomplished by means of pins 3 and in particular by means of an upper pin 3a and of a lower pin 3b.
Each pin, in its motion of insertion and extraction in corresponding holes present in the booms and aligned at the time of the insertion/extraction, is associated to a corresponding actuator, which in the illustrated case is a hydraulic cylinder 4 and more specifically an upper hydraulic cylinder 4a and a lower hydraulic cylinder 4b.
As shown in Figures 3, 4 and 5, each cylinder 4 is provided with a rod 5 whose end is rigidly connected by means of a bridge bracket 6 to the pin 3, in such a way that the extension of the rod corresponds to the complete extraction of the pin from the booms (Figure 4 and 5) with the possibility of removing the excavation boom 2 or accessory boom relative to the base boom 1, whilst the retraction of the rod corresponds to the insertion of the pin into the booms (Figure 3) with consequent fastening of the booms.
The insertion/extraction of the pins is thus achieved by operating the rods of the cylinders fastened thereto which, by means of a control positioned in the booth or otherwise in a control unit, allow a rapid insertion/extraction of said pins in mechanically perfect fashion, thanks also to the fact that mechanical abutments, not illustrated, are present, which allow a correct alignment of the holes 7 of the pins present on the base boom 1 and on the excavation boom 2.
Originally, the hydraulic cylinders 4 are positioned internally to the booms or otherwise to the frame of the machine and do not work in overhang as in the prior art, with considerable operative advantages, such as a better reliability and longer working life, thus reducing costs for the replacement of worn cylinders.
Moreover, with the apparatus according to the present invention the insertion/extraction of the pins takes places with a single person, with execution times more than halved with respect to manual technology, without any injury hazard or physical effort for the operator.

Claims

Pinned boom for an earth moving machine, wherein the pinned boom comprises a hydraulic apparatus for the insertion and the extraction of at least one pin, wherein the hydraulic apparatus being of the type comprising at least one hydraulic cylinder (4) whose rod (5) is operatively connected with said at least one pin (3) whose insertion and extraction respectively associate or disassociate a base boom (1) with respect to a second boom (2) or accessory boom, wherein said at least one hydraulic cylinder (4) is applied internally in the pinned base boom (1) characterised in that the pin (3), when inserted, spans the whole boom's (1,2) width.
Pinned boom as claimed in claim 1, wherein mechanical abutments are present for a correct alignment of holes (7) present on the base boom (1) and on the second boom (2) for the pins (3).
Pinned boom as claimed in claim 1, wherein to each cylinder (4) is associated only one pin (3) and to each pin (3) is associated a corresponding unique cylinder (4).