GB2362371A

GB2362371A - Bucket with improved breakout force

Info

Publication number: GB2362371A
Application number: GB0011814A
Authority: GB
Inventors: Gary Miller; Ronald Keith Miller
Original assignee: MILLER WELDING ENGINEERS Ltd
Current assignee: MILLER WELDING ENGINEERS Ltd
Priority date: 2000-05-16
Filing date: 2000-05-16
Publication date: 2001-11-21
Anticipated expiration: 2020-05-16
Also published as: GB2362371B; GB0011814D0

Abstract

A bucket 10 for attachment to a coupler 41 of a digger or excavator has at least the front connecting pin 25 positioned within the confines of side plates 1a so as to provide a lower overall height thereby increasing the brake out force. Preferably both coupling pins 25, 27 are so positioned (Figs 3, 5 or 8).

Description

2362371 1 BUCKET WITH IMPROVED BREAKOUT FORCE This invention relates to a

bucket for a mechanical digger and, in particular, to a bucket designed for attachment to a operating arm of a mechanical digger using a coupler especially a coupler of the type disclosed in our U.K. Patent Application No. 0003267.2.

Buckets for use with mechanical diggers can be of various different sizes and widths but in almost all cases, the bucket comprises: a pair of spaced side plates, each of which has a leading edge and an at least partially convex arcuate trailing edge, which has a first or lower part extending rearwardly from a bottom part of the leading edge, and rearwardly thereof, a second or rear part, and forwardly and above the rear part, a third or upper part, a front of which is joined to an upper region of the leading edge; an at least partially arcuate base plate extending between said first and second parts of the at least partially convex arcuate trailing edges of the said side plates to define a bottom and a rear of the bucket, and also extending between upper regions of the side plates to define the upper internal confines of the bucket; a pair of parallel spaced bucket pin support plates on the top of the bucket located above that part of the base plate defining the upper internal confines of the bucket; and further strengthening plates extending between the side plates, in their upper regions externally of the base plate, and respective ones of the pair of spaced bucket pin support plates, which bucket pin support plates are located in a central area of the upper region of the bucket, and support a front bucket pin and a rear bucket pin disposed to the rear of the front bucket pin. A plurality of spaced, hardened teeth may be secured to a front, lower leading edge of the base plate.

A bucket as described above is hereinafter referred to as a bucket of the type described.

Until fairly recently, buckets for mechanical diggers were secured directly to the operating arm of the mechanical digger by means of the front bucket pin which is removable to allow connection between the bucket and the operating arm, and a ram associated with the operating arm of the digger for pivoting the bucket was connected to the bucket via the rear bucket pin which was also removable. In such an arrangement, it was normally necessary for the operator of the mechanical digger to dismount from his cab, remove the two bucket pins then get back into his cab and manipulate the operating arm of the digger to a position 2 such that it could be connected to the bucket, then dismount from the cab again, insert the front bucket pin in the aligned apertures in the bucket pin support plates and an aperture on the free end of the operating arm, and then subsequently to connect the ram to the bucket after perhaps getting back into the cab, manipulating the operating arm to align the apertures for the rear bucket pin in the bucket pin support plates and an aperture on the free end of the ram, and then inserting the rear bucket pin in place and locking the pins in position as necessary.

More recently, however, it has become more commonplace to fit a coupler to the operating 10 arm of the digger, thereby allowing the operator of the digger to connect the bucket to the operating arm without having to dismount from his cab, merely by manipulating the operating arm of the digger so that a forward facing U-shaped hook arrangement on the front lower end of the coupler could be hooked around the front bucket pin, the bucket then being partially lifted off the ground so as to swing the rear bucket pin into a position which allows the rear bucket pin to be clamped by a further clamping arrangement on the rear underside of the coupler.

Vnifle such a largely automatic pickup of the bucket using the coupler has proved extremely satisfactory for the excavator operator, it has resulted in reduced digging efficiency of the mechanical digger. This is because the distance between the front pivot pin on the bucket and the front edge of the base plate of the bucket or, if the bucket is fitted with teeth, the front edge of the digging teeth has been increased due to the presence of the coupler. As it will be appreciated, when the bucket is connected to the operating ann of the mechanical digger with a coupler, the thus connected bucket will be pivoted relative to the operating arm not about the front bucket pin but about the front pivot pin connecting the coupler to the operating arm of the digger. This means that when the ram is activated to pivot the bucket about its pivotal support on the operating arm, a greater force will have to be applied through the ram to achieve the same breakout force with the bucket than would be the case when the bucket is directly pivotally connected to the operating arm by its front pivot pin.

The present invention seeks to overcome this problem and provide a bucket for a mechanical digger which can be connected to the operating arm of the mechanical digger 3 using a coupler but without there being a reduction in breakout force for a given force from the ram to cause the bucket to pivot about its connection to the operating arm.

According to one aspect of the present invention, we provide a bucket of the type described 5 wherein for a predetermined bucket width and bucket volume, the ratio of the distance between the centre of the front bucket pin and the leading edge of the arcuate base plate or a plurality of digging teeth attached thereto, and the distance between the centres of the two bucket pins is greater than said ratio on a prior art bucket of said predetermined width and volume.

According to another aspect of the present invention, we provide a bucket of the type described, wherein, for a predetermined bucket width and bucket volume, the moment arm about the front bucket pin provided by a leading edge of the arcuate base plate or a plurality of teeth secured thereto, is less than the equivalent moment arm on a prior art bucket of the same predetermined width and volume.

According to a flirther aspect of the present invention, we provide a bucket of the type described wherein, for a predetermined bucket width and bucket volume, the distance between the leading edge of the arcuate base plate or of a plurality of teeth attached thereto and the bucket front pivot pin is less than the equivalent distance on a prior art bucket of the same width and volume.

In prior art buckets, the bucket pins are supported on a pair of spaced bucket pin support plates located in a central area of an upper region of the bucket and upstanding beyond the third or upper parts of the spaced side plates of the bucket. In the bucket of the present invention, the front and rear bucket pins are located in bucket pin support plates which are located substantially within the confines of the third or upper parts of the spaced side plates of the bucket, thus resulting in a bucket having a lower or more squat profile than a bucket of the prior art but having the same bucket width and volume. Because of the lower or more squat profile of the bucket of the present invention, it is necessary, in order to achieve the same bucket volume, to increase the depth of the bucket, that is the dimension between the leading edge of the side plates of the bucket and the rear of the bucket defined by that 4 portion of the base plate extending between the second parts of the pair of spaced side plates.

Several embodiments of bucket for a mechanical digger according to the present invention are now described by way of example, with reference to the accompanying drawings in which:

FIGURE 1 is a side elevation of a prior art bucket of a given width and volume attached to the operating arm of a mechanical digger by a coupler;

FIGURE 2 is a view similar to Figure 1 of the same width and volume as that of Figure 1, but showing a bucket according to the present invention attached to a coupler (but omitting the operating arm); FIGURE 3 is a view similar to Figure 2 and showing a second embodiment of bucket according to the present invention and of the same width and volume as that of Figure 1; FIGURE 4 shows the bucket of Figure 2 without the coupler; FIGURE 5 shows the bucket of Figure 3 without the coupler; FIGURE 6 shows the bucket and coupler as shown in Figure 2 superimposed over the prior art bucket and coupler of Figure 1;

FIGURE 7 is a rear perspective view of a modified version of the bucket of Figure 4; and FIGURE 8 is a view similar to Figure 3, showing a preferred embodiment of the invention.

Referring now to Figure 1, the bucket shown therein has two spaced side plates, only one of which is shown at 1, the side plate having a leading concave arcuate edge 3 (which could be straight) and a convex arcuate trailing edge 5. The trailing edge 5 has a rear arcuate part 4 which is connected to the leading edge 3 by a lower part 7 extending rearwardly from a bottom part of the leading edge 3 and is connected to the upper region of the leading edge 3 by an upper part 9 having an elbow therein as shown at 11. A base plate 13 extends between the lower part 7 of the two side plates 11 and the rear arcuate parts 4 of the side plates 1, and an upper region 15 of the base plate 13 extends between upper regions of the side plates 1 but spaced from the upper parts 9 thereof, the upper region 15 extending via an elbow 17 to an upwardly extending part 19 which terminates just short of the upper ends of the leading edges 3 of the side plates 1. At least one pair of strengthening plate 21 is provided above the upper region 15 of the base plate 13, as shown, each strengthening plate 21 is of generally L-shaped construction and is welded to the inner face of the upper region of the side plate 1 but spaced inwardly a few centimetres from its outer edge, including the outer edge of the elbow 19. Two parallel spaced bucket pin support plates 23 are welded to the upper region 15 of the base plate 13 and the strengthening plates 21, instead of extending completely across the width of the bucket between the two side plates 1, only extend inwardly from the inner face of the upper region of the respective side plate 1 to their adjacent bucket pin support plate 23. A front bucket pin 25 is supported within a forward aperture formed in each of the plates 23 and a rear bucket pin 27 is located in a rear aperture in the two plates 23, all in known manner.

Also shown in Figure I is the lower end of a support arm 31 of a mechanical digger and the lower end of a ram 33. The ram is in fact extended downwardly by means of a ram extension member 35 which is pivotally connected by a pivot 37 to the ram 33, the pivotal connection 37 being held outwardly away from the operating arm 31 by means of a spacer link 39 which itself is pivotally connected at one end to the operating arm 31 and at its opposite end to the pivot 37.

As can clearly be seen from Figure 1, the bucket is connected to the operating arm 31 and ram 33 by a coupler 41 which has a front pivot pin 43 pivotally connecting it to a lower end of the operating arm 31 and a rear pivot pin 45 pivotally connecting it to a lower end of the ram extension member 35. A generally forwardly extending U-shaped hook-like aperture 45 is provided on a lower leading edge of the coupler 41 and a downwardly extending inverted U-shaped jaw 49 is provided on the lower rear edge of the coupler.

6 When it is desired to pick up the bucket, the operator of the mechanical digger activates the operating arm 31 so that the hook-like aperture 45 is hooked around the front bucket pin 25 and then farther activates the mechanical digger using the ram 33 so that the inverted Ushaped jaw 49 overlies the rear bucket pin 27. A hydraulically operated latch or the like is then activated to lock the rear bucket pin 27 within the U-shaped jaw 49. Once locked in position, the excavator operator can then dig with the bucket in conventional manner, although it will be noticed that the bucket, instead of being pivotally attached to the operating arm 31 of the mechanical digger by means of its front bucket pin 25, is pivotally attached thereto by means of the front pivot pin 43 of the coupler. The relative distances between the tip of a plurality of teeth 47 secured to the leading edge of the base plate 13 and the respective pins 25 and 33 are shown as being 1413 units and 1675 units in the drawing. The angle defined by lines joining the tip of the teeth 47 and the front bucket pin 25 in the one case, and joining the centres of the bucket pins 25,27 is 100'. This is also the angle between a line joining the coupler pins 43, 45 and a line joining the tip of the teeth 47 and the front coupler pin 43. This means that the breakout force of the bucket, that is the force necessary to dig by pivoting the bucket about the pin 43 by extension of the ram 33 is reduced for a given down force provided by the ram 33 relative to the breakout force if the bucket was directly secured to the operating arm 3 1, i.e. the coupler 41 was not used. The relative breakout forces will depend, in the one case on the measurements rn and r and, on the other, by the measurements M and R (and on the above mentioned angles).

The buckets according to the present invention as shown in Figures 2 to 8 overcome this disadvantage.

In the construction shown in Figure 2, parts which are identical to those shown in Figure 1 are given the same reference numerals, whereas similar parts are given the same reference numerals followed by the letter a. Referring to Figure 2, the bucket has a pair of spaced side plates I a having an arcuate convex leading edge 3a and a partially arcuate convex trailing edge 5a. The partially arcuate trailing edge 5a has an arcuate rear part 4a which is connected to the leading edge 3a by a first or lower part 7a, a part 6 of which is straight (and hardened) and a farther part 8 of which is slightly curved, and the upper portion of the partially arcuate trailing edge extends forwardly thereof as shown at 9a, and then downwardly via an elbow 11 a to join the upper end of the concave leading edge 3 a. As is 7 apparent from Figure 7, a forward section 10 of the side plate 1 shown at 10 is somewhat thicker than a rearward section 12. The boundary between the sections 10 and 12 may be straight as shown at 14 in Figure 7, or arcuate as shown at 16 in Figure 2. As is readily apparent from both Figure 2 and Figure 7, the two end plates I a are connected together in a similar manner to the prior art construction shown in Figure 1 by a base plate 13a, largely in the same manner as in the prior art construction. However, the upper region 15a of the base plate is substantially longer than the upper region 15 of the prior art construction, although it does terminate in an upturned portion 19a, as in the prior art construction.

Also as in the prior art construction, a pair of spaced bucket pin support plates 23a are welded to the rear face of the upper part of the arcuate portion of the base plate 13a and to its upper region 15a. At their upper foremost ends 24 which are curved (see Figure 7), the two bucket pin support plates 23a are located within the confines of the upper regions of the side plates la, i.e. the arcuate portions 24 do not project outwardly beyond the elbows lia of the side plates la. As can clearly be seen in both Figure 2 and Figure 7, a strengthening plate 21 a is welded to a rear region of the upper region 15a of the base plate 13a as shown at 26, each of the plates 21a extending between upper regions of the side plates 1 a and their adjacent bucket pin support plates 23 a. At its uppermost end, each of the plates 21 a is downtumed, as shown at 28, the downtumed portion being connected to the remainder of the plate 21a by an elbow 30. A further strengthening plate 32 also extends between respective side plates and bucket pin support plates la and 23a respectively, as shown in Figure 2, to stiffen up that region of the bucket. As is clearly apparent from both Figures 2 and 7, a rear bucket pin 27 extends between the two bucket pin support plates 23a and a front bucket pin 25 is also provided. This front bucket pin 25 is fixed, e.g. welded in position, and, as is clearly apparent from both Figures 2 and 7, is located within the confines of the side plates 1 a. This is perhaps even more clearly illustrated in Figure 4. In accordance with the present invention, the distance between the centre of the pivot pin 43 on the coupler 41 and the tip of the teeth 47 shown in Figure 2 comprises 1413 units, as distinct from 1675 units, as shown in the prior art construction of

Figure 1. This is because of the location of the bucket pin 25a.

It should be noted that the width and the volume of the bucket shown in Figures 2 and 4 is identical to the width and the volume of the prior art bucket of Figure 1. In order to

8 achieve this, it is necessary for the distance D of the bucket of the invention, i.e. its depth, to be considerably greater than the distance d of the prior art bucket shown in Figure 1. it will also be noticed that the distance H, i.e. the distance from the centre of the bucket pin 25a to the tip of its bucket teeth, is substantially less than the distance h, i.e. the distance from the bucket prior art pin 25 to the tip of the bucket teeth. Because of these relative dimensions, the moment arm M of the tip of the teeth 27 of the bucket of the invention about the pivotal connection of the bucket via its coupler pivot pin 43 is substantially less than the moment aim m of the tip of the teeth 47 of the prior art bucket about its pivotal connection 43 to the operating arm 3 1. This means that for a given operating force applied to the bucket of the invention by the ram 33, the reaction force at the teeth 47 will be less than the reaction force provided at the teeth 47 of the prior art construction of Figure 1.

In the embodiment shown in Figures 3 and 5, the bucket has the same volume as that of Figures I and 2 and parts similar to those of Figure 2 are identified with the same reference numeral followed by b. It can be seen that the portion 15b of the bucket base plate which defines the upper confines of the bucket, instead of being straight as shown at 15a in Figure 2, is kinked as shown at 15b. The principal difference between this construction of bucket according to the invention and that of Figure 2 is that the rear upper external face of the bucket is boxed in by strengthening plates 34 which replace the plates 21a. The geometry of the moment arms of the bucket is otherwise similar to that of Figure 2, although its internal contour, i.e. vertical section through the bucket differs somewhat (deeper from top to bottom and not quite so deep from the tip of its teeth to its rear end 15b).

It will be noticed from a comparison between Figures 1 and 2 that the bucket pin 25 of the prior art construction is spaced rearwardly from the tip of the teeth 47 considerably more than is the case of the bucket pin 25a. In other words, p is substantially greater than P. In the Figure 3 construction, P' is even less than the dimension P shown in Figure 2 and this means that the moment arm M- is considerably less than the moment arm M. This means that the bucket shown in Figure 3 is even more efficient than that shown in Figure 2. It will also be noticed that x = x' and R > r.

9 Referring now to Figure 8, parts similar to the parts shown in Figure 3 have the same reference numerals, but supplemented by a c. This bucket, because of the presence of plates 34c has a "closed top". It is the most efficient of all the buckets of the invention; although the bucket has the same width and volume as the bucket shown in Figures 3 and 5, it has a full curved upper portion 18 of the base plate 13c. The efficiency of the bucket is because of the geometry of the pins 25c,27c and pins 43c,45c, which provide for angles V and 8 of 100' and 103' respectively, and a distance between the tip of the teeth 47c and the centre of the coupler front pin 43c of only 1387 units. This is even less than the distance between the tip of the teeth 47 and the front bucket pin 25 in the prior art coupler of Figure 1 of 1413 units (where angle 8 is 100').

It is preferred that, in each of the buckets of the present invention, both bucket pins 25a,27a; 25b,27b and 25c,27c are welded in position. This then means that the buckets have to be used with a coupler, and a dedicated bucket/coupler system is thus provided. In all these constructions, because of the relatively small distance between front coupler pin and the tip of the bucket teeth 47, it is not possible for the tip of the teeth 47, when the bucket is in a "tucC position, to touch the cab of the excavator, which can occur with some prior art bucket and coupler combinations.

It will of course be understood that the present invention has been described above purely by way of example, and modifications of detail can be made within the scope of the invention.

Claims

1. A bucket of the type described wherein, for a predetermined bucket width and bucket volume, the ratio of the distance between the centre of the front bucket pin and the leading edge of the arcuate base plate or a plurality of digging teeth attached thereto, and the distance between the centres of the two bucket pins is greater than said ratio on a prior art bucket of said predetermined width and volume.

2. A bucket of the type described, wherein, for a predetermined bucket width and bucket volume, the moment arm about the front bucket pin provided by a leading edge of the arcuate base plate or a plurality of teeth secured thereto, is less than the equivalent moment arm on a prior art bucket of the same predetermined width and volume.

3. A bucket of the type described, wherein, for a predetermined bucket width and bucket volume, the moment arm about the front bucket pin provided by a leading edge of the arcuate base plate or a plurality of teeth secured thereto, is less than the equivalent moment arm on a prior art bucket of the same predetermined width and volume.

4. A bucket according to claim 1, 2 or 3, wherein the front and rear bucket pins are located in bucket pin support plates which are located substantially within the confines of the third or upper parts of the spaced side plates of the bucket, thus resulting in a bucket having a lower or more squat profile than a bucket of the prior art but having the same bucket width and volume.

5. A bucket for a mechanical digger, substantially as hereinbefore described with reference to Figure 2 and 4 or 3 and 5 or 7 or 8 of the accompanying drawings.

6. A bucket and coupler combination, substantially as hereinbefore described with reference to Figure 2 or Figure 3 or 8 of the accompanying drawings.