CA2473403A1 - Excavation bucket - Google Patents

Description

EXCAVATION BUCKET
The present invention relates to excavation buckets and more particularly, relates to excavating buckets which include an impact actuator assembly.
Excavating buckets are wel! known in the art and are designed to excavate hard soils and the like. One such excavating bucket is shown in U.S. patent No. 6,574,891 wherein the bucket includes a bucket body, a moveable head, a moveable floor mounted between the moveable head and an impact actuator provided between and mounted to the bucket body and the moveable head.
Other arrangements are shown in the art and thus, one may have reference to U.S. patent No. 4,625,438 which teaches an excavating bucket having a leading edge provided with a row of individually pneumatically driven digging teeth.
Each digging tooth is connected to a pneumatic hammer that that reciprocates the tooth at high speed. Since each tooth is connected to an individual pneumatic impact hammer, the total weight of the excavating bucket is much higher than the weight of a conventional bucket which is a disadvantage when fihe arm of the machine carrying the bucket is fully extended.
It is an object of the present invention to provide an impact excavating bucket which is of relatively simple design with a stable floor and reciprocating teeth which are easily interchangeable.
According to the present invention, there is provided an excavation bucket having an impact actuator assembly in association with a fixed tool guide, or nosepiece.
In the bucket of the present invention, and contrary to the above described arrangement, the nosepiece is securely attached to the bucket rather than being

2 moveable. The teeth or other tools are moveable within the nosepiece by use of an impact actuator assembly as will be discussed in greater detail herein below.
It will be understood that although the present invention will be described with respect to a plurality of teeth, other tools may be utilized and to this end, reference may be had to U.S. Patent 6,574,891, the teachings of which are incorporated herein by reference.
Having thus generally described the invention, reference will be made to the accompanying drawings illustrating an embodiment thereof, in which:
Figure 1 is a top plan view of an excavator bucket with one actuator assembly and fitted with abutments arrangement;
Figure 2 is similar to figure 1, except the nosepiece has been Gutted to see its internal components;
Figure 3 is a cross-sectional side view of an excavator bucket with one actuator assembly and fitted with abutments arrangement;
Figure 4 is an exploded perspective view of an excavation bucket;
Figure 5 is an exploded rear perspective view of the bucket of Figure 1 and Figure 5A is a detail thereof;
Figure 6 is a front perspective view of the bucket of figure 1, with some elements removed so to show internal components;
Figure 7 is a rear perspective view of the bucket of figure 1, with some elements removed so to show the abutment members arrangement;

3 Figure 8 is a rear perspective view of the bucket without abutment members, with some elements removed to facilitate the representation;
Figure 9 is a top plan view of the actuator; Figure 9A being an exploded view thereof;
Figure 10 is a front perspective view;
Figures 11 and 12 are perspective views of the bucket with the top cover removed;
Figures 13 and 14 are similar views as Figures 11 and 12 showing a bucket with two impact actuator assemblies and two independent nosepieces;
Figure 15 is an exploded perspective view of an excavation bucket with two impact actuator assemblies and two independent nosepieces;
Figures 16 and 17 are perspective views of buckets with two impact actuator assemblies, one common nosepiece and sharing the same dividing wall; and Figures 18 and 19 show two different options for removable wear bushings into the nosepiece.
Referring to the drawings in greater detail and by reference characters thereto, there is illustrated in Figures 1, 2 and 3 an excavating shovel which is generally designed by reference numeral 10. In this respect, shovel 10 is similar to that shown in U.S. Patent No. 5,574,891, Shovel 10 has a floor 12, a back wall 14, side walls 16 with mounting brackets having apertures 20 therein for securement purposes.

4 Depending upon its use and its width, each shovel 10 is fitted with one ar more impact actuator assemblies 26 (refer to figures 13 to 17 for different arrangements). When used in series (more than one per shovel 10), each impact actuator assembly 26 is mounted side by side, separated by internal walls.
Upon the specific design of the shovel, the multiple impact actuator assemblies may share the same dividing internal wall 24.
Each one of the impact actuator assemblies 26 are provided with a pair of lateral walls 22, positioning spacers and a rear plate 39 to house an impact actuator assembly 26. As may be seen in the drawings, impact actuator 26 is provided with a rear cushion 28, center cushions 30 and front cushion 32. A cover 34 is secured to the interior wall 22 to enclose the impact actuator assembly 26. Cover 34 is secured to the lateral wall 22 by means of screws 36. Similarly, a front wall 38 is secured to the lateral wall 22 by screws 40.
Each one of the impact actuator assemblies 26 also includes an actuator head which functions as an anvil. One end of the anvil fits into its actuator while the other end (wider) hits the end of tool pins 48 (number of tool pins undetermined, min of 1, no max). Tools pins 48 are mounted in a nosepiece 44 which is secured to the bucket floor 12 and to the bucket side walls 16 or lateral walls 22. To this end, nosepiece 44 rnay by welded thereto. In turn, tool pins 48 are moveable within slots or guides 45 farmed in nosepiece 44. Tool pins are retained in position by a backing rod 60. In a multi actuator impact assembly's application, there is no specific rule for specifying the quantity of nosepieces 44. Each ane of the impact actuator assembly 26 within a shovel 10 may have its own nosepiece 44, as well as one nosepiece 44 may guide tools pins 48 for more than one impact assembly 26, with no limitation in size nor number of tools pins 48 being guided.
Similarly, the tool locking mechanism may have one or more rod 60 to secure all of the tools pins 48. Each rod 60 may serve one or many nosepiece 44.

Referring to figures 6 and 9, each one of the impact actuator 26 has 2 hydraulic connections 66 (inlet and outlet), one grease connection 68 for its anvil wear bushing, and one connection 70 for compressed air used for actuator seal in a underwater use. Every line connecting the actuators run from inside the bucket up

5 to outside connectors 67-69-71, therefore allowing the operation and basic maintenance of the impact actuator unit from the outside (no cover removal).
Each one of the impact actuator assemblies 26 could be totally independent of each other, in terms of operation and motion. In such a case, the actuators 26 are not interconnected. The tools pins 48 driven by one assembly are totally free from the other assemblies. The hydraulic connections are independent. However, actuators 26 of different assemblies may be hydraulically interconnected. In such a case, the tools work in phase. Similarly, actuator could share common gas chamber (to reduce space).
Application 1- Hard soil, with long anvil 42 and abutment members 54. As may be best seen in Figure 5 and 7, there are provided a plurality of recesses 56 within nosepiece 44. Each recess 56 has a spring member 52 mounted therein. One end of spring 52 seats on end wall of recess 56 while the other end thereof seats against an abutment member 54. The abutment member 52 is secured in place with a abutment screw 50. As seen in Figure 7, abutment member 54 extents slightly beyond the end wall 58 of the nosepiece 44. During normal operation in hard soil, pressure is always applied against the tools pins, thus to the anvil 42.
The course of the anvil 42 is short and as long as the hard material is not broken, the pressure on the tools pins 48 will prevent the anvil 42 of hitting the inner wall surface 58 of the nosepiece 44. However, when the hard material is broken, the pressure at the tip of the tools pins 48 is nil and the anvil 42 is pushed against the nosepiece 44. With the abutment arrangement, we now control the impact force of the anvil 42 on the nosepiece 44 after a pressure release on the tools pins 48.
With the proper spring tension adjustment of the abutments 54, the deceleration of the anvil 42 is controlled so that the impact is minimized and set as desired.
The

6 resistance of spring member 52 will also ensure that actuator head 42 is returned to its position for the next stroke.
Application 2- Hard soil. with long anvil 42 only (no abutment members 54).
Refer to F~ure 8. In this option of impact actuator arrangiement, they are no abutment members 52, s~prinas 52 and screws 50 secured into the nosepiece 44. The normal os'eration in hard soil is similar to application 1 described above.
The difference is when the hard material is broken and the pressure at the tip of the tool sins 48 is n I the anvil 42 will directly hit the inner face of the nosepiece 58.
The impact force will not be controlled.
Application 3- Hard soil, with short anvil 42. In this option of impact actuator arrangement, the design is such as even with the actuator piston in its full extended position (out of actuator 26), the anvil 42 will not be pushed against the nosepiece inner wall 58. The anvil 42 free space is longer that the piston stroke.
Consequently, when hard material is broken, the pressure release of the tips of the tools pins 48 will not make the anvil 42 to hit the inner wall of the nosepiece 58.
There are no damageable impacts on the nosepiece 44. In the case of material removal with no pressure on the tools pins 48 (for example: clay), this application may not be suitable since less vibration is generated to the bucket walls.
Application 4- Clay, Impact vibration. This application refers to a situation where we have a bucket full of material (example: clay) sticking to the inner surfaces and therefore difficult to clean out. Any of the three applications described above could be used for clay removal. The vibration generated to the shovel 10 by the each one of the impact design will ease the extraction of clay out of the shovel 10.
Referring to application 1, the abutment arrangement 54 allows to operate the impact actuator 26 with not load on the tools pins 48, and to control the impact of the anvil 42 onto the inner nosepiece wall 58, such as generating enough vibration to force the clay (or other material) out of the bucket. Similarly, application 2 can also be used with no load on the tool pins 48 but without controlling the impact.

The direct impact of the anvil 42 with the nosepiece 44 will generate more vibration that application 1. The impact force will be absorbed by the welds of the nosepiece 44 to the shovel 10. Application 3 will also generate vibration to the shovel 10 (less than the two previous applications). The impact will be absorbed by internal components of the impact actuator 26.
Application 5- Clay, vibrating cover. Without limitation to the previous application (no 4), the impact actuator assembly 26 may be fitted with a mechanical mechanism, making the actuator cover 34 (or part of it), to move longitudinally with the anvil 42. The back and forth motion of the moveable cover (or part of it) will facilitate the disengaging of soil packed in the bucket body 10.
Because of very abrasive applications, the nosepiece 44 and specially its guiding holes 45 wilt require the use of appropriated harden material. As other alternatives, removable wear bushings 64 may be used (refer to Figures 18 and 19).
It will be understood that the above described embadiment is for purposes of illustration anly and that changes and modifications may be made thereto without departing from the spirit and scope of the invention.

Claims