US3057494A

US3057494A - Excavating apparatus

Info

Publication number: US3057494A
Application number: US790182A
Authority: US
Inventors: Vaino J Holopainen; James F King
Original assignee: WAIN ROY CORP
Current assignee: WAIN ROY CORP
Priority date: 1959-01-30
Filing date: 1959-01-30
Publication date: 1962-10-09
Anticipated expiration: 1979-10-09

Description

1962 v. J. HOLOPAINEN ETAL 3,05

EXCAVATING APPARATUS Filed Jan. 50, 1959 3 Sheets-Sheet 1 FIG. I.

llVl/E/VTORS VAl/VO J. HOLOPA/NE N JAMES KIA/6 ATTORNEY Oct. 9, 1962 v. J. HOLOPAINEN ETAL 3,057,494

EXCAVATING APPARATUS Filed Jan. 50, 1959 5 Sheets-Sheet 2 VMUW7J HULORAHWDV JMMESE'KM@ Arron/) Oct. 9, 1962 v. J. HOLOPAINEN ETAL 3,057,494

EXCAVATING APPARATUS Filed Jan. 50, 1959 3 Sheets-Sheet 5 INVENTORS VA//v0 J. HOLOPA/NEN JAMES E KING B) a j Aha/ma atent 3,057,494 Patented Oct. 9, 1962 3,057,494 EXtTAVATiNG APPARATUS Vaino J. Holopainen, Rutland, and James F. King, Princeton, Mass, assignors to Wain-Roy Corporation, Hubbardston, Mass, a corporation of Massachusetts Filed Jan. 30, 1959, Ser. No. 790,182 11 Claims. (Cl. 214-138) This invention relates to an excavating apparatus, and more particularly to a backhoe, or the like, for attachment to a tractor.

'It has become common practice to apply an excavating apparatus, such as a backhoe or the like to one end of a tractor. Such apparatus usually consists of a number of articulated arms actuated by hydraulic cylinders. This type of apparatus is subject to a number of difficulties; one of the difliculties experienced is that encountered because of the fact that the cylinders are exposed to contact by stones and boulders encountered during the digging operation and by engagement with the side of a truck or other apparatus with which the backhoe is being used. Other drawbacks lie in the lack of a rugged construction for performing some of the operations. Also, some of the designs used are rather expensive to manufacture. These and other shortcomings of the prior art devices have been obviated in a novel manner by the present invention.

It is, therefore, an outstanding object of the present invention to provide an excavating apparatus composed of articulated arms which are actuated by hydraulic cylinders, wherein the cylinders are protected from damage.

Another object of the invention is the provision of a backhoe having a novel manner of adjusting the angularity of the stabilizers relative to the main body of the attachment.

A further object of the invention is the provision of a backhoe having a novel and useful geometrical arrangement of the elements.

A still further object of this invention is the provision of a rugged and simple manner of bringing about swinging action of a backhoe relative to its support.

It is another object of the instant invention to provide an excavating apparatus which is simple and rugged in construction, which may be inexpensively manufactured, and which is capable of a long life of useful service with a minimum of maintenance.

Although the novel features which are believed to be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, the mode of its operation and the manner of its organization, may be better understood by referring to the following description, taken in connection with the accompanying drawings forming a part thereof, in which:

FIG. 1 is a perspective view of apparatus embodying the principles of the present invention,

FIG. 2 is a side view of the invention with portions broken away for clarity of presentation,

FIG. 3 is an enlarged perspective view of a portion of the invention, and

FIG. 4 is an enlarged perspective view of another portion of the invention.

Referring first to FIG. 1, the excavating apparatus, indicated generally by the reference numeral 10, is shown in use with a tractor 11 of the ordinary farm type. The apparatus consists of a housing 12 which is directly connected to the frame of the tractor and contains a control box 13 from the top of which projects valve handles 14. integrally fastened to the outer portion of the housing 12 is a vertically-elongated support member 15 which is capable of swinging relative to the housing 12 about a vertical axis. Also attached to the housing 12 on its opposite sides are stabilizers 16 and 17. Attached to the support member 15 for pivotal movement about a horizontal axis is a boom 18. Attached to the boom at a position somewhat removed from its outer end is a dipper stick 19, having a bucket 21 pivotally attached to its lower end. A boom cylinder 22 of the double-acting hydraulic type is attached at one end to the lower part of the support member 15 and the other end is pivotally attached to an intermediate portion of the boom 18 by means of a pivot pin 23. It will be understood that for the purposes of this description the expression cylinder is used in its popular sense, i.e., as designating an actuator consisting of a cylinder and a piston. A second double-acting hydraulic dipper stick cylinder 24 is connected at one end to the outer end of the boom 18 and at its other end to an intermediate portion of the dipper stick 19 by means of a pivot pin 25. A third doubleaoting hydraulic bucket cylinder 26 is connected at one end to an intermediate portion of the dipper stick 19 and at the other end to the bucket 21 at a point considerably spaced from the point of attachment of the dipper stick thereto.

FIG. 2 shows particularly well the inter-relationship of the boom, dipper stick, and bucket with their respective cylinders. The boom 18 is shown as being of a triangular form and as being hollow, at least a portion of the boom cylinder 22 residing within the boom. Generally speaking, the boom 18 is formed with triangularly-shaped side walls 27 joined by

edge walls

28 and 29 on two long sides of the triangle only. The third, short side, designated by the reference numeral 31, is open to receive the cylin der 22. At the apex of the triangular sides 27 opposite the edge 31 the edge walls 28 and 29' terminate some distance from the apex to permit the boom to receive one end of the cylinder 24 and the pivot pin 32 associated therewith. The apex of the boom 18 defined by the edge '31 and the edge Wall 28 is fastened to the support member 15 by means of a horizontal pivot pin 33. The lower end of the boom cylinder 22 is fastened to the lower end of the support member 15 by means of a horizontal pivot pin 34.

The dipper stick 19' also is provided with side walls 35 of a generally triangular shape. However, it should be noted that one of the sides is not entirely straight and, as a matter of fact, is provided with a break. The two side walls are joined by edge walls 36 and 37, the edge wall 37 extending almost entirely along the side of the side Walls 35 and terminating just short of the lower apex which is attached to the bucket 21 by means of a pivot pin 38. The edge wall 36 terminates just short of the apex occupied by the pivot pin 38 in the same way, but terminates in the upper direction a considerable distance from the upper apex. The dipper stick is provided with an open edge 39 for reception of the cylinder 24 and also is provided with the supplemental open edge 41, thus permitting the two side walls 35 to embrace the upper part of the boom 18' and to pivotally attached thereto by means of a pivot pin 42. The upper part of the edge wall 37 is provided with a pair of cars 43 to which the upper end of the cylinder 26 is connected by means of a pivot pin 44. The other end of the cylinder 26 is connected to the bucket 21 by means of a pivot pin 45. The boom cylinder 22, the dipper stick cylinder 24, and the bucket cylinder 26 are provided with suitable piping arrangements, not shown, which are connected with a source of hydraulic fluid, also not shown, through valves which are actuated by the valve handles 14 in the usual manner. The dimensions of the boom 18 and the dipper stick 19 are dictated by the amount of swing desired in these elements, the distance between the edge walls being selected so that the cylinders will have sufficient room to swing within the boom and the dipper stick during operation of the apparatus.

In FIG. 3 is shown the means by which the support member is capable of swinging movement about the housing 12. In this view it will be seen that the boom 18 and the cylinder 22 are positioned toward one side of the tractor 11 and the support member 15 is at a right angle to the position shown in FIG. 1. Horizontal cars 46 and 47 extend from the housing 12 and are connected to the support member 15 by a pivot pin 48. Similarly, ears 49 and 51 extend horizontally from the housing and are connected to the upper part of the support member 15 by means of a pivot pin 52. The

pivot pins

48 and 52 are vertically aligned to define a vertical hinge axis for the support member 15.

Bars

53 and 54 extend from the lower portion of the support member 15 and embrace the lower end of the boom cylinder 22 and are connected thereto by means of the pivot pin 34. Similarly,

ears

55 and 56 extend from the upper part of the support member 15 and are connected to the lower end of the boom 18 by means of a pivot pin 33. An ear 57 extends laterally from the mid-portion of the support member 15 and is connected by a pivot pin 58 to

parallel links

59 and 61 which are joined by a rivet 62, and, therefore, act as a single link. The other ends of the

links

59 and 61 are connected by a pivot pin 63 to the outer end of a piston rod 64 forming part of a single-acting swing cylinder 65 which is enclosed within the housing 12. A fulcrum plate 66 extends laterally across the inner side of the support member 15 and extends a considerable distance from either side. It will be understood that another set of ears, links, piston rod and swing cylinder are mounted on the other side of the support member for swinging in the other direction.

Referring next to FIG. 4, wherein is shown the particular construction of the stabilizers, the stabilizer 16 is shown as attached to the housing 12 and as comprising a bracket 67 which is attached to the housing 12 by means of vertical pivot pins 68, thus permitting the swinging of the whole unit forwardly and backwardly. The bracket 67 is bifurcated and is provided with two legs 69 and 71 through the outer extremities of which extends a pin 72 which extends through the end of the stabilizer 16 for swinging of the stabilizer about a horizontal pivot. Also extending through the legs 69 and 71 is a pivot pin 73 by which a double-acting hydraulic stabilizer cylinder 74 is attached at its upper end to the bracket 67. The bracket 67 is also provided with a horizontal car 75 which normally resides between two horizontal cars 76 and 77 extending laterally from the housing 12. The ears are provided with vertical apertures 78 and 79 and the car 75 is provided with similar apertures. A locking pin 81 extends through the apertures in the ears to hold the ears 75 in a fixed position in alignment with either the apertures 78 or the apertures 79. It will be understood, of course, that more than two such locating apertures could be used.

The operation of the excavating apparatus of the invention will now be readily understood in view of the above description. When the tractor 11 has been located in a suitable position to perform the excavating operation desired, oil under pressure is admitted to the stabilizer cylinders 74 to move the stabilizers 16 and 17 downwardly into the earth. This is done by manipulation of the proper valve handle 14 to admit pressure oil to one side of the cylinder 74 and to permit oil to drain from the other side of the cylinder to a reservoir. In this condition most of the weight of the apparatus in the tractor is carried on the stabilizers rather than on the rear wheels of the tractor. Then, by manipulation of the proper valve handles 14, the whole apparatus can be swung from side to side by means of the swing cylinders 65, the boom can be moved up and down by means of the boom cylinder 22, the dipper stick can be swung about the pivot pin 42 by means of the dipper stick cylinder 24 and the bucket can be swung about the pivot pin 38 on the lower end of the dipper stick by means of the bucket cylinder 26. As is shown in FIG. 2, the swinging of the boom and dipper stick to extended positions, such as are shown in dotted lines, causes the cylinder 22 to swing within the boom 18 and the dipper stick cylinder 24 to swing within the dipper stick 19. The inner cavity of the boom and of the dipper stick are selected of such a size as to permit the cylinders to have such swinging motion as is necessary to produce the action desired. It will be noted that, during this swinging action, the boom cylinder 22 and the dipper stick cylinder 24 are fully protected from engagement with the sides of the excavation, with structural elements associated therewith, with a truck which may be present, or with large boulders which might tend to strike the cylinders and make their operation less effective.

The operation of the swing mechanism, which is best shown in FIG. 3, is quite simple. As the piston rod 64 is drawn into the cylinder 65, the

links

59 and 61 pivot about the pivot pin 58 and strike the edge of the fulcrum plate 66. This produces a rotative force on the support member 15 about the pivot pins 48 and 52 and tends to swing the boom 18 and the boom cylinder 22 toward a forward position. As the swinging continues, the

links

59 and 61 will eventually leave the fulcrum plate 66 and the connections between the cylinder 65 and the pivot pin 58 will be in a straight line through the links and the piston rods 64. This movement can be continued until the boom 18 occupies an opposite position from that shown in the drawing; that is to say, until the boom extends longitudinally from the tractor in the direction of the observer of the drawing rather than away from the observer. The reverse swinging action, of course, takes place because of a similar swing cylinder associated with the other side of the support member 15.

The adjustment of the stabilizers 16 is almost self-evident from an inspection of FIG. 4. By removing the locking pin 81, the stabilizer and its cylinder 74 is free to swing about the pivot pin 68. This can be continued until the aperture in the ear 75 aligns itself along with another set of apertures in the ears 76 and 77 at which time the locking pin 81 may be re-inserted through the apertures to lock the stabilizer in a different position of angularity with respect to the housing 12 and to the entire excavating apparatus. This adjustment of the stabilizer may be brought about when it is deemed necessary by the particular excavating job being performed. Under certain digging conditions it may be desirable to have the stabilizers extend at right angles to the length of the tractor, while in others they may extend definitely rearwardly of the tractor at a considerable angle to the lateral position.

While certain novel features of the invention have been shown and described and are pointed out in the annexed claims, it will be understood that various omissions, substitutions, and changes in the forms and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention.

The invention having been thus described, what is claimed as new and desired to secure by Letters Patent, is:

1. An excavating apparatus, comprising a supporting member adapted to be attached to a vehicle, a boom attached at one end to the supporting member for swinging movement about a horizontal axis, a tubular dipper stick attached at one end to an intermediate part of the boom for swinging movement about a horizontal axis, a bucket attached to the other end of the dipper stick for swinging movement about a horizontal axis, a double-acting hydraulic boom cylinder connected at one end to the supporting member at a part thereof spaced from the attachment of the boom thereto and at the other end to an intermediate portion of the boom, a double-acting hydraulic dipper stick cylinder having a substantial portion lying in the interior of the dipper stick, said dipper stick cylinder being connected at one end to the other end of the boom and at the other end to an intermediate part of the dipper stick, and a double-acting hydraulic bucket cylinder connecting an intermediate part of the dipper stick to a part of the bucket substantially spaced from the attachment of the dipper stick thereto.

2. An excavating apparatus, comprising a supporting member adapted to be attached to a vehicle, a boom attached at one end to the supporting member for swinging movement about a horizontal axis, a dipper stick having a hollow triangular conformation having a long closed side, a long partially-closed side, and a short open side, the dipper stick being attached at an apex adjacent the open side to an intermediate part of the boom for a swinging movement about a horizontal axis, a bucket attached to the other end of the dipper stick for swinging movement about a horizontal axis, a double-acting hydraulic boom cylinder connected at one end to a supporting member at a part thereof spaced from the attachment of the boom thereto and at the other end to an intermediate portion of the boom, a double-acting hydraulic dipper stick cylinder connected at one end to the other end of the boom and at the other end extending into the interior of the dipper stick through the said open side and pivotally connected to an intermediate part of the dipper stick, and a doubleacting hydraulic bucket cylinder connecting an intermediate part of the dipper stick to a part of the bucket substantially spaced from the attachment of the dipper stick thereto.

3. An excavating apparatus, comprising a supporting member adapted to be attached to a vehicle, a boom of hollow triangular conformation having two long closed sides and a short open side, the boom being attached at an apex adjacent the said open side to the supporting member for swinging movement about the horizontal axis, a dipper stick of a hollow triangular conformation having a long closed side, a long partially-closed side, and a short open side, the dipper stick being attached at an apex adjacent the said open side to an intermediate part of the boom for swinging movement about a horizontal axis, a bucket attached to the other end of the dipper stick for swinging movement about a horizontal axis, a double-acting hydraulic boom cylinder connected at one end to the supporting member at a part thereof spaced from the attachment of the boom thereto and having its other end extending into the interior of the boom through the said open side and pivotally connected to an intermediate portion of the boom, a double-acting hydraulic dipper stick cylinder connected at one end to another apex of the boom and having its other end extending into the interior of the dipper stick to the said open side and pivotally connected to an intermediate part of the dipper stick, and a double-acting hydraulic bucket cylinder connecting an intermediate par-t of the dipper stick to a part of the bucket substantially spaced from the attachment of the dipper stick thereto.

4. An excavating apparatus, comprising a housing adapted to be attached to a vehicle, a supporting member swingably attached to the housing, a boom attached at one end to the supporting member to a swinging movement about a horizontal axis, a tubular dipper stick attached at one end to an intermediate part of the boom for swinging movement about a horizontal axis, a bucket attached to the other end of the dipper stick for swinging movement about a horizontal axis, a double-acting hydraulic boom cylinder connected at one end to the supporting member at a part thereof spaced from the attachment of the boom thereto and at the other end to an intermediate portion of the boom, a double-acting hydraulic dipper stick cylinder connected at one end to the other end of the boom and at the other end to an intermediate part of the dipper stick, the dipper stick cylinder having a substantial portion lying within the dipper stick, a double-acting hydraulic bucket cylinder connecting an intermediate part of the dipper, stick to a part of the bucket substantially spaced from the attachment of the dipper stick thereto, a stabilizer attached to the '6 housing at each side of the attachment of the supporting member thereto, each stabilizer being connected to the housing for adjustment about a vertical axis, and means associated with the housing and each stabilizer to lock the stabilizer in a selected position of adjustment.

5. An excavating apparatus, comprising a housing adapted to be attached to a vehicle, a suporting member swingably attached to the housing, a boom attached at one end to the supporting member for swinging movement about a horizontal axis, a hollow dipper stick attached at one end to an intermediate par-t of the boom for swinging movement about a horizontal axis, a bucket attached to the other end of the dipper stick for swinging movement about a horizontal axis, a double-acting hydraulic boom cylinder connected at one end to the supporting member at a part thereof spaced from the attachment of the boom thereto and at the other end an intermediate portion of the boom, a double-acting hydraulic dipper stick cylinder connected at one end to the other end of the boom and at the other end to an intermediate part of the dipper stick, the dipper stick cylinder having a substantial portion residing within the dipper stick and a double-acting hydraulic bucket cylinder connecting an intermediate part of the dipper stick to a part of the bucket substantially spaced from the attachment of the dipper stick thereto, an ear extending laterally from an intermediate portion of the supporting member at a position spaced substantially from the axis of swinging attachment to the housing, a swing cylinder mounted in the housing, a link connecting the ear to the cylinder which is pivotally connected to both, and a fulcrum plate extending later-ally from the support member for engagement by the link on occasion.

6. An excavating apparatus, comprising a housing adapted to be attached to a vehicle, a supporting member swingably attached to the housing, a boom attached at one end to the supporting member for swinging movement about a horizontal axis, a dipper stick of a hollow triangular conformation having a long closed side, a long partially-closed side and a short open side, the dipper stick being attached at an apex adjacent the said open side to the intermediate part of the boom for swinging movement about a horizontal axis, a bucket attached to the other end of the dipper stick for swinging movement about a horizontal axis, a double-acting hydraulic boom cylinder connected at one end to the supporting member at a part thereof spaced from the attachment of the'boom thereto and at the other end to an intermediate portion of the boom, a double acting hydraulic dipper stick cyl inder connected .at one end to the other end of the boom and having its other end extending into the interior of the dipper stick through the said open side and pivotally connected to an intermediate portion of the dipper stick, and a double-acting hydraulic bucket cylinder connecting an intermediate part of the dipper stick to a part of the bucket substantially spaced from the attachment of the dipper stick thereto, and a stabilizer attached to the housing at each side of the attachment of the supporting member thereto, each stabilizer being connected to the housing for adjustment about a vertical axis and means associated with the housing and each stabilizer to lock the stabilizer in a selected position of adjustment,

7. An excavating apparatus, comprising a housing adapted to be attached to a vehicle, a sup-porting member swingably attached to the housing, a boom attached at one end of the supporting member for swinging movement about a horizontal axis, a dipper stick of a hollow triangular conformation having a long closed side, a long partially-closed side, and a short open side, the dipper stick being attached at an apex adjacent the said open side to an intermediate part of the boom for swinging movement about a horizontal axis, a bucket attached to the other end of the dipper stick for swinging movement about a horizontal axis, a double-acting hydraulic boom cylinder connected at one end to the supporting member at a part thereof spaced from the attachment of the boom thereto and at the other end to an intermediate portion of the boom, a double-acting hydraulic dipper stick cylinder connected at one end to the other end of the boom and having its other end extending into the interior of the dipper stick through the said open side and pivotally connected to an intermediate part of the dipper stick, and a double-acting hydraulic bucket cylinder connecting an intermediate part of the dipper stick to a part of the bucket substantially spaced from the attachment of the dipper stick thereto, an ear extending laterally from the intermediate portion of the supporting member at a position spaced substantially from the axis of swinging attachment to the housing, a swing cylinder mounted in the housing, a link connecting the ear to the cylinder which is pivotally connected to both, and a fulcrum plate extending laterally from the support member for engagement by the link on occasion.

8. An excavating apparatus, comprising a housing adapted to be attached to a vehicle, a supporting member swingably attached to the housing, a boom of hollow triangular conformation having two long closed sides and a short open side, the boom being attached at an apex adjacent the said open side to supporting member for swinging about a horizontal axis, a dipper stick of a hollow triangular conformation having a long closed side, a long partially-closed side, and a short open side, the dipper stick being attached at an apex adjacent the said open side to an intermediate part of the boom for swinging movement about the horizontal axis, a bucket attached to the end of the dipper stick for swinging movement about a horizontal axis, a double-acting hydraulic boom cylinder connected at one end to the supporting member at a part thereof spaced from the attachment of the boom thereto and having its other end extending into the interior of the boom through the said open side and pivotally connected to an intermediate portion of the boom, a double-acting hydraulic dipper stick cylinder connected at one end to another apex of the boom and having its other end extending into the interior of the dipper stick through the said open side and pivotally connected to an intermediate part of the dipper stick, and a doubleacting hydraulic bucket cylinder connecting an intermediate part of the dipper stick to a part of the bucket substantially spaced from the attachment of the dipper stick thereto, and a stabilizer attached to the housing at each side of the attachment of the supporting member thereto, each stabilizer being connected to the housing for adjustment about a vertical axis, and means associated with the housing and each stabilizer to lock the stabilizer in a selected position of adjustment.

9. An excavating apparatus, comprising a housing adapted to be attached to a vehicle, a supporting member swingably attached to the housing, a boom of hollow triangular conformation having two long closed sides and a short open side, the boom being attached at an apex adjacent the said open side to the supporting member for swinging movement about the horizontal axis, a dipper stick of a hollow triangular conformation having a long closed side, a long partially-closed side, and a short open side, the dipper stick being attached at an apex adjacent the said open side to an intermediate part of the boom for swinging movement about a horizontal axis, a bucket attached to the other end of the dipper stick for swinging movement about a horizontal axis, a doubleacting hydraulic boom cylinder connected at one end to the supporting member at a part thereof spaced from the attachment of the boom thereto and having its other end extending into the interior of the boom through the said open side and pivotally connected to an intermediate portion of the boom, a double-acting hydraulic dipper stick cylinder connected at one end to another apex of the boom and having its other end extending into the interior of the dipper stick through the said open side and pivotally connected to an intermediate part of the dipper stick, and a double-acting hydraulic bucket cylinder connecting an intermediate part of the dipper stick to a part of the bucket substantially spaced from the attachment of the dipper stick thereto, an ear extending laterally from an intermediate portion of the supporting member at a position spaced substantially from the axis of swinging attachment to the housing, a swing cylinder mounted in the housing, a link connecting the ear to the cylinder which link is pivotally connected to both, and a fulcrum plate extending laterally from the supporting member for engagement by the link on occasion.

10. An excavating apparatus, comprising a housing adapted to be attached to a vehicle, a supporting member swingably attached to the housing, a boom of hollow triangular conformation having two long closed sides and a short open side, the boom being attached at an apex adjacent the said open side to the supporting member for swinging movement about a horizontal axis, a dipper stick of a hollow triangular conformation having a long closed side, a long partially-closed side, and a short open side, the dipper stick being attached at an apex adjacent the said open side to an intermediate part of the boom for swinging movement about a horizontal axis, a bucket attached to the other end of the dipper stick for swinging movement about a horizontal axis, a double-acting hydraulic boom cylinder connected at one end to the supporting member at a part thereof spaced from the attachment of the boom thereto and having its other end extending into the interior of the boom through the said open side and pivotally connected to an intermediate portion of the boom, a double-acting hydraulic dipper stick cylinder connected at one end to another apex of the boom and having its other end extending into the interior of the dipper stick through the said open side, and pivotally connected to an intermediate part of the dipper stick, and a double-acting hydraulic bucket cylinder connecting an intermediate part of the dipper stick to a part of the bucket substantially spaced from the attachment of the dipper stick thereto, a stabilizer attached to the housing at each side of the attachment of the supporting member thereto, each stabilizer being connected to the housing for adjustment about a vertical axis, and means associated with the housing and each stabilizer to lock the stabilizer in a selected position of adjustment, an ear extending laterally from an intermediate portion of the supporting member at a position spaced substantially from the axis of swinging attachment to the housing, a swing cylinder mounted in the housing, a link connecting the ear to the cylinder which link is pivotally connected to both, and a fulcrum plate extending laterally from the support member for engagement by the link on occasion.

11. An excavating apparatus, comprising a supporting member adapted to be attached to a vehicle, a boom attached at one end to the supporting member for swinging movement about a horizontal axis, a tubular dipper stick attached at one end to an intermediate part of the boom for swinging movement about a horizontal axis, a bucket attached to the other end of the dipper stick for swinging movement about a horizontal axis, a doubleacting hydraulic boom cylinder connected at one end to the supporting member at a part thereof spaced from the attachment of the boom thereto and at the other end to an intermediate portion of the boom, a double-acting hydraulic dipper stick cylinder connected at one end to the other end of the boom and at the other end to an intermediate portion of the dipper stick, the dipper stick cylinder having a substantial portion lying within the dipper stick and a double-acting hydraulic bucket cylinder connecting an intermediate part of the dipper stick to a part of the bucket spaced from the attachment of the dip per stick thereto.

(References on following page) References Cited in the file of this patent 2,846,094

UNITED STATES PATENTS 2,216,070 Ekbom et a1. Sept. 24, 1940 3 1 2,450,152 Miller Sept. 28, 1948 5 2,764,306 Dorkins Sept. 25, 1956 2,801,012 Lederer July 30, 1957 2,831,589 Way Apr. 22, 1958 10 Pilch Aug. 5, 1958 Slate Aug. 12, 1958 Lapsley Nov. 18, 1958 Walker Apr. 7, 1959 OTHER REFERENCES Preliminary Operators Manual OM-U 11301U For the John Deere 50 and 5/1 Backhoes, pp. 10 and 11.