US3809250A

US3809250A - Telescopic apparatus

Info

Publication number: US3809250A
Application number: US00351284A
Authority: US
Inventors: J Pilch
Original assignee: Ware Machine Works Inc
Current assignee: Ware Machine Works Inc
Priority date: 1973-04-16
Filing date: 1973-04-16
Publication date: 1974-05-07
Anticipated expiration: 1991-05-07

Abstract

Telescopic apparatus adapted for use with graders, trenchers or backhoes, loaders, lifters and the like which include an earth moving implement, dipperstick, hook or other tool, attachment or the like. The apparatus includes a first support which is adapted to be supported in relation to the ground. The boom includes a first longitudinally extending part which is pivotally associated with the first support for substantially vertical swinging movement relative thereto and a second longitudinally extending part which is slidable relative to the first part. It also includes longitudinally reciprocable means, such as an hydraulic cylinder and ram, and means for connecting one end thereof to the first part. A first arcuate member, such as a sheave or sprocket is rotatably mounted on the other end of the longitudinally reciprocable means substantially in alignment with its longitudinal centerline and a second arcuate member is rotatably mounted on said first longitudinally reciprocating means in spaced longitudinal relationship from said first arcuate member and from said first longitudinally reciprocable means and substantially in alignment with the longitudinal centerline thereof. First elongate flexible means, such as a chain or cable, is passed over the first arcuate member, one end thereof is connected to the first part and the other end is connected to the second part adjacent to its inner end. Second elongate flexible means is passed over the second arcuate member, one end thereof is connected to the first part and the other end thereof is connected to the second part at a locality towards the outer end thereof. A device or tool of the type described above is associated with the outer end of the second part. The second part and the attached device or tool are moved longitudinally relative to the first part upon actuation of the longitudinally reciprocable means, thereby facilitating the grading, digging, loading and/or lifting with the device. According to a preferred embodiment, the apparatus also includes another longitudinally reciprocable means for swinging the first part substantially vertically relative to the ground, one end of this means being pivotally connected to the first support and the other end being pivotally connected to the first part.

Description

[451 May 7,1974

[ TELESCOPIC APPARATUS [75] Inventor: John S. Pllch, Ware, Mass.

[7.3] Assignee: Ware Machine Works, Inc., Ware,

Mass.

22 Filed: Apr. 16,1973 211 Appl. No.: 351,284

Primary Examiner-Robert J. Spar Assistant ExaminerJohn Mannix [5 7] ABSTRACT Telescopic apparatus adapted for use with graders, trenchers or backhoes, loaders, lifters and the like which include an earth moving implement, dipper stick, hook or other tool, attachment or the like. The apparatus includes a first support which is adapted to be supported in relation to the ground. The boom includes a first longitudinally extending part which is pivotally associated with the first support for substantially vertical swinging movement relative thereto and a second longitudinally extending part which is slidable relative to the first part. It also includes longitudinally reciprocable means, such as an hydraulic cylinder and ram, and means for connecting one end thereof to the first part. A first arcuate member, such as a sheave or sprocket is rotatably mounted on the other end of the longitudinally reciprocable means substantially in alignment with its longitudinal centerline and a second arcuate member is rotatably mounted on said first longitudinally reciprocating means in spaced longitudinal relationship from said first arcuate member and from said first longitudinally reciprocable means and substantially in alignment with the longitudinal centerline thereof. First elongate flexible means, such as a chain or cable, is passed over the first arcuate member, one end thereof is connected to the first part and the other end is connected to the second part adjacent to its inner end. Second elongate flexible means is passed over the second arcuate member, one end thereof is connected to the first part and the other end thereof is connected to the second part at a locality towards the outer end thereof. A device or tool of the type described above is associated with the outer end of the second part. The second part and the attached device or tool are moved longitudinally relative to the first part upon actuation of the longitudinally reciprocable means, thereby facilitating the grading, digging, loading and /or lifting with the device.

According to a preferred embodiment, the apparatus also includes another longitudinally reciprocable means for swinging the first part substantially. vertically relative to the ground, one end of this means being pivotally connected to the first support and the other end being pivotally connected to the first part.

l7 Claims, 11 Drawing Figures 3309.250 SHEEI 3 0f 4 PATENTEDIAY 1:914

ow m2? om ow 1 TELESCOPIC APPARATUS BACKGROUND OF THE INVENTION This invention relates to telescopic apparatus for use with graders, trenchers or backhoes, loaders,lifters or the like which include an earth moving implement, dipperstick, hook or other tool, attachment or the like associated with the remote end of a boom.

Certain embodiments of such apparatus have ineluded a boom or dipperstick which includes two longitudinally extending parts which are slidable relative to each other and an earth moving implement associated with the outer end of one of those parts. In addition, means has been provided for causing one of said parts to be moved longitudinally relative to the other part to facilitate grading, digging and/or loading. Such apparatus are disclosed in my US. Pat. Nos. 3,140,000 dated July 7, 1964; 3,536,217 dated Oct. -27, 1970; and 3,653,131 dated Apr. 4, 1972 and also in the following U.S. Pat. Nos.:

Inventor Number Date 2,784,855 March 12, I957 Acker 2,984,373 May 16, 1961 Przybylski 3,298,548 Jan. 17, 1967 Long et al.

A further object of the invention is to provide such an apparatus in which the boom may be swung vertically relative to the ground.

A further object is to provide such an apparatus which is economical to manufacture and which may be easily serviced.

Other objects and advantages of the invention will be apparent to persons skilled in the art from the following description taken in conjunction with the ac-' companying drawings.

SUMMARY OF THE INVENTION necting one end thereof to the first part.

A first arcuate member, such as a sheave, sprocket or the like, is rotatably mounted on the other end of the first longitudinally reciprocable means, substantially in alignment with its longitudinal centerline. A second arcuate member is rotatably mounted on said other end of the first longitudinally reciprocable means in spaced longitudinal relationship from the first arcuate member and from the first longitudinally reciprocable means centerline thereof.

First elongate flexible means, such as a chain or cable, is passed over the first arcuate member, one end thereof is connected to the first part and the other end is connected to the second part adjacent to its inner end. Second elongate flexible means is passed over the second arcuate member, one end thereof is connected to the first part and the other end thereof is connected to the second part at a locality towards the outer end thereof.

An earth moving implement, dipperstick, crane, hook or other tool, attachment or the like, hereinafter collectively referred to as a device, is associated with the outer end of the second part. The second part and the attached device are moved longitudinally relative to the first part upon actuation of the longitudinally reciprocable means, thereby facilitating the grading, excavating, loading, or other action of the device.

According to a preferred embodiment, the apparatus also includes another longitudinally reciprocable means for swinging the first part substantially vertically relative to the ground, one end of this means being pivotally connected to the first support and the other end being pivotally connected to the first part.

In one embodiment, the first longitudinally extending part comprises an elongate slot extending through one wall thereof and one end of the first elongate flexible means is connected to a member which is' attached to the second part and which extends through the slot.

In another embodiment, the first longitudinally extending part comprises a second elongate slot extending through one wall thereof, located towards the outer end of the first part from the endv of the first elongate 'slot and with its longitudinal centerline substantially in alignment with the first elongate slot. This second slot is adapted to receive the means for supporting one end of means for rotating a dipperstick of a backhoe about its pivotal connection to the boom during at least a portion of the relative longitudinalmovement of the first and second longitudinally extending parts. It may also receive the means for connecting the other end of the second elongate flexible means to the second part during a portion of said movement. I

In the preferred embodiment, the first longitudinally reciprocable means and the first and second arcuate members are located exteriorly of the first-longitudinally extending part.

In one embodiment, the longitudinally reciprocable means comprises an hydraulically operable cylinder and ram which are located adjacent to one wall of the first part.

The apparatus also preferably comprises another longitudinally reciprocable means for swinging the first part substantially vertically relative to the ground, means for pivotally connecting one end of this reciprocable means to the first support and means for pivotally connecting the other end of this means to the first part.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view showing a grader ernbodying this invention with the longitudinal centerline of the parts which support the grader blade generally parallel to the ground line;

FIG. 2 is a plan view looking at the top of the elements shown in FIG. I;

FIG. 3 is a side elevational view showing the parts which support the grader blade positioned with their longitudinal centerline moved downwardly towards the ground line and the parts which support the grader blade in an extended position from the position of FIG.

FIG. 4 is a side elevational view showing the parts which support the grader blade positioned with their longitudinal centerline inclined at an angle to the ground line rather than generally parallel to it as shown in FIG. 3;

FIG. 5 is a section on the line 55 of FIG. 2;

FIG. 6 is a perspective view of portions of the longitudinally reciprocable means for moving the parts which support the grader blade longitudinally relative to each other;

FIG. 7 is a view looking at the end of the outer one of the parts which support the grader blade.

FIG. 8 is a side elevational view showing the outer end of the boom, the dipperstick and the bucket of a trencher or backhoe embodying this invention;

FIG. 9 is a plan view looking at the top of the elements shown in FIG. 8;

FIG. 10 is a side elevational view of a crane or lifter embodying this invention; and

FIG. 11 is a plan view looking at the top of the elements shown in FIG. 10.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The Embodiment Shown in FIGS. 1 to 7 of the Drawings Referring now more particularly to the drawings,

wherein similar reference characters designate corresponding parts throughout, the invention relates to telescopic apparatus adapted for use with graders, trenchers or backhoes, loaders, lifters and the like which include an earth moving implement, dipperstick, hook or other tool, attachment or the like associated with the remote end of a boom.

In FIGS. 1 to 7 of the drawings, a grader is shown in which the earth moving implement is a grader blade 10 pivotally connected at 11 to the remote end of a boom 15 which in turn is pivotally connected at to a first support 21 for substantially vertical swinging movement relative to the ground.

The first support is slidably supported for movement up and down relative to a second support 22 by longitudinally reciprocable means 23 in a manner to be described in detail below.

The second support is supported by a third support (not shown) by substantially vertical pivots (not shown) which pass through orifices 25 in the plates 26 which are welded to the side. plates 22A of the second support.

The second support is movable about said substantially vertical pivots in a substantially horizontal direction relative to the third support by a pair of hydraulically reciprocable means (not shown) as disclosed in my said copending application Ser. No. 235,262 filed Mar. 16, 1972 and in my US. Pat. No. 3,042,236 dated July 3, 1962 to which reference is made herein.

tions 218 which are slidable between the guide members 22B.

The first support 21 is moved up and down substantially vertically relative to the second support 22 by the longitudinally reciprocable means 23 which comprises an hydraulic cylinder 23A and ram 238, the cylinder being connected to an hydraulic system by conduits which are not shown.- The upper end of the cylinder 23A is pivotally connected to the side members 22A by a pin 23C (FIGS. 1 and 2). The ram 23B is pivotally connected to the first support 21 by the pin 23D which passes through an extension of the ram and through the enlarged portions 213 of the support.

The first support is shown in an elevated position in FIG. 4, in one lowered position in FIG. 1 and in a further lowered position in FIG. 3.

The means for swingably moving the boom substantially vertically relative to the ground and to the first support comprise the longitudinally reciprocable means 30, the ram 30A of which is pivotally connected at 31 to the first support 21 and the cylinder 30B of which is pivotally connected by the pin 32 to the

members

35A and 358, the lower ends of which are secured to the first or outer longitudinally extending part of the boom 15. i

The grader blade is rotated about the pivot 11 by the longitudinally reciprocable means which comprises the cylinder 45A and ram 45B. The cylinder is pivotally connected between the lugs by the pin 51, the lugs being attached to the second or inner part 60 of the boom 15 near its outer end. The ram 458 is pivotally connected between the lugs 10A which are secured to the grader blade 10.

The second longitudinally extending part 60 of the boom is slidable within and relative to the first longitudinally extending part 40. The meansfor moving or sliding the second longitudinally extending part relative to the first longitudinally extending part comprises longitudinally reciprocable means, which in the embodiment illustrated, comprises the cylinder 65A and the ram 65B. The cylinder 65A is connected to the hydraulic system by hoses 65C. The cylinder 65A is mounted between the

members

35A and 35B above the top wall of the first part 40 as shown in FIGS. 1 and 5. One end of the cylinder 65A is pivotally secured between the lugs 65D which are secured to the first part 40 of the boom. The end of the ram 65B is secured to a pair of spaced plates 65E as shown in FIG. 6.

A first arcuate member 75, which may be a sheave, sprocket or similar means, is rotatably mounted between the plates 65E by a pin A. It will be noted that it is substantially in alignment with the longitudinal centerline of the first longitudinally reciprocable means 65A, 6513.

A second arcuate member 76, which also may be a sheave, sprocket or similar means, is rotatably mounted between the plates 65E by a pin 76A. It will be noted that the arcuate member 76 is in spaced longitudinal relationship from the first arcuate member 75 and from theouter end of the ram 658 of the first longitudinally reciprocable means and substantially in alignment with the longitudinal centerline thereof.

First elongate flexible means 80, which may be a cable, chain or similar means, passes over the first arcuate member 75. It has one end connected to the lug 80A which is secured to the first part 40 by means of the member 358. The other end of the flexible means 80 is connected to the lug 808 which is secured to the top wall of the second part 60 near itsinner end. The lug 80B extends upwardly through the longitudinal slot 40A (FIG. 2), provided in the top wall of first part 40.

The side walls of the first part are held together in spaced relationship by

the'lugs

40C and 40C and the

bolts

40B and 40B, 40C and40B being located adjacent to the outer end of the first part and the

lugs

40B and 40C being located inwardly from the outer end of the boom. The bolt 403 also serves to form one end of the slot 40A. Consequently as the second part 60 of the boom is moved outwardly relative to the first part 40 of the boom, the outward movement is arrested or stopped when the lug 808 contacts the bolt 408' as shown in FIG. 4.

Second elongate flexible means 90, which may be a chain, cable or similar means, passes over the second arcuate member 76. It has'one end connected to the outer member 40 by the longer lug 40C and its other end connected to the second part 60 by the pin 91 which extends between the lugs 50as shown in FIG. 2. It will be noted that the pin 91 is located at a locality towards the outer end of the second part.

A second elongate slot 40E (FIG. 2) extends through the top wall of the first part 40 and its extends from the bolt 403' to the bolt 403 with its longitudinal centerline substantially in alignment with the first elongate slot 40A. This second elongate slot is for use in the embodiment shown in FIGS. 8. and 9 of the drawings as will be explained below.

The first longitudinally reciprocable means and the first and second arcuate members are located exteriorly of said first part so they are readily accessible for servicing.

In operation, the operator can control the hydraulic system of the vehicle to operate all of the hydraulically reciprocable means by means of control levers which are not shown. 4

In operation, when it is desired to slide or move the second part 60 longitudinally with respect to the first part 40, the ram 658 is retracted into the cylinder 65A and the elongate flexible means in cooperation with the arcuate means pulls the second part 60 into the first part 40 and during such movement, the lug 80B traverses the longitudinal slot 40A in a direction from left to right looking at the drawings.

When it is desired to slide or move the second part 60 longitudinally outwardly relative to the first part 40, hydraulic fluid is admitted to the cylinder 65A so that the ram 658 moves from right to left looking at the drawings and the elongate flexible means-causes the lug 808 to move from right to left in the slot 40A and this causes the second part 60 to move from right to left.

Since the arcuate members are of the same diameter, the elongate flexible means remain tight at all times.

The right-hand portion of the boom 15 may be moved upwardly and downwardly relative to the second support 22 by controlling the flow of hydraulic fluid to the cylinder 23A.

may be omitted, the right hand end of the first part 40 of the boom may be pivotally connected to the support 22 and the ram 30A may be pivotally connected to the support 22, thus eliminating the support 21 and the hydraulically reciprocable means 23 as is well known in the art and as is shown in my US. Pat. Nos. 3,042,236, 3,140,000 and 3,536,217. With such a construction the support 22 becomes the first support referred to in claims 1 and 16.

THE EMBODIMENT SHOWN IN FIGS. 8 AND 9 OF THE DRAWINGS A boom, dipperstick and bucket of a trencher or backhoe are shown in FIGS. 8 and 9 of the drawings.

Most of the boom elements of this embodiment are similar to the corresponding elements of the boom of the first embodiment and corresponding-numerals have been applied to such elements in FIGS. 8 and 9.

The trencher or backhoe comprises a dipperstick which is attached to the member 103 which is pivotally connected at 101 to the outer end of the second part 60. The longitudinally reciprocating means 45' comprises a cylinder 45A and a ram 458' which are strong enough to rotate the dipperstick 100 about the pivot 101. Because the cylinder 45A and ram 458' are longer than the cylinder 45A and ram 458 of the first embodiment the lugs 50' are located farther inwardly from the outer end of the second part 60 and the bolt 40B of the first embodiment is omitted. The ram 458' of the longitudinally reciprocable means 45 is pivotally connected at 102 to the member 103 and the cylinder 45 is pivotally connected to the pin 51' which extends between the outer ends of the lugs 50'. The bucket 105 is pivotally connected at 106 to the outer end of the dipperstick.

Link 107 is pivotally connected at l08to the bucket. Link 109 is pivotally connected at 110 to the dipperstick.

The longitudinally reciprocable means 112 comprises an hydraulic cylinder 1 12A and a ram 1 128. The cylinder 112A is pivotally connected at 113 to the member 103 and the ram 1128 is pivotally connected at 111 to the

links

107 and 109. The cylinder 112A is connected to an hydraulic system by conduits which are not shown.

The relative longitudinal movements of the first and second parts of the boom are effected by the cylinder 65A, ram 658,

arcuate members

75, 76 and first and second elongate

flexible means

80, 90. However because of the length of the cylinder 45A and ram 458' and the spacing of the lugs 50' from the outer end of the second part 60 the bases of the'lugs 50 enter the second longitudinal slot 40E when the second part is moved a substantial distance inwardly relative to the first part 40 as shown in FIGS. 8 and 9. Since the lugs 50' support the pin 91 to which one end of the second elongate flexible means 90 is attached, the lower portions of these lugs form part of the means for connect ing that end of said flexible means to the second part and the slot 45E is adapted to receive them during at least a portion of the relative longitudinal movement of THE EMBODIMENT SHOWN IN FIGS. 10 AND 11 OF THE DRAWINGS A boom and a hook of a crane or lifter are shown in FIGS. 10 and 11.

The boom elements are similar to the corresponding elements of the boom of the first embodiment and corresponding numerals have been applied to them;

However the boom is shown pivotally connected at 115 to the second support 22. In addition the third longitudinally reciprocable means 116 is located below the boom rather than above it. It comprises the hydraulic cylinder, 116A and ram 1168, the hydraulic cylinder being connected to an hydraulic system by conduits which are not shown.

The cylinder 116A is pivotally connected at 117 to the second support 22 and the ram 116B is pivotally connected at 118 to lugs 119 which are secured to the first part 40 of the boom.

The relative longitudinal movement of the first and second parts of the boom are effected in the same way as in the first embodiment by the cylinder 65A, ram 658,

arcuate members

75, 76 and first and second elongate

flexible means

80, 90.

In this third embodiment the support 21 and the hydraulically reciprocable means 23 of the first embodiment have been omitted, the first part 40 has been pivotally connected to the support 22at 115 and the hydraulically reciprocable means 116 has been pivotally connected to the support 22 at 117. Thus in this third embodiment the support 22 becomes the first support" referredto in claims 1 and 16.

The hook 120 is pivotally secured at 121 to the end of the second part 60. The second elongate flexible means 90 is secured to the second part 60 at a locality near its outer end by the lug 122. One end of the first elongate flexible means 80 is secured to the first part by the member 123 and its other end is secured to the inner end of the second part by the member 80B as in the first embodiment.

While three desirable embodiments of the invention have been shown and described, it is to be understood that this disclosure is for the purpose-of illustration only and that various changes in shape, proportion and arrangement of parts as well as the substitution of equivalentelements for those herein shown and described may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

I claim:

1. Telescopic apparatus comprising a first support adapted to be supported in relation to the ground,

a first longitudinally extending part pivotally associated with said first support for substantially vertical swinging movement relative thereto,

a second longitudinally extending part which is slidable relative to said first part,

first longitudinally reciprocable means,

means for connecting one end of said first longitudinally reciprocable means to said first part,

a first arcuate member,

means for rotatably mounting said first arcuate member on the other end of said first longitudinally reciprocable means, substantially in alignment with its longitudinal centerline,

first elongate flexible means passing over said first arcuate member,

means for connecting one end of said first elongate flexible means to said first part,

means for connecting the other end of said first elongate flexible means to said second part,

a second arcuate member,

means for rotatably mounting said second arcuate member on said other end of said first longitudinally reciprocable means in spaced longitudinal relationship from said first arcuate member and from said first longitudinally reciprocable means and substantially in alignment with the longitudinal centerline thereof,

second elongate flexible means passing over said second arcuate member,

means for connecting one end of said second elongate flexible means to said first part,

means for connecting the other end vof said second elongate flexible meansto said second part and a device associated with the outer end of said second part, whereby said second part and said device are moved longitudinally relative to said first part upon actuation of said first longitudinally reciprocable means.

2. Apparatus according claim 1 wherein said first part comprises a first elongate slot extending through one wall thereof and said means for connecting the other end of said first elongate flexible means to said second part comprises a member which is attached to said second part and extends through said slot.

3. Apparatus according to claim 2 wherein said first part comprises a second elongate slot extending through one wall thereof, located towards the outer end of said first part from the end of said first elongate slot and with its longitudinal centerline substantially in alignment with said first elongate slot.

4. Apparatus according to claim 3 which also comprises a dipperstick, means forpivotally connecting the dipperstick to the outer end of said second part, second longitudinally reciprocable means, means for pivotally connecting one end of said second longitudinally reciprocable means to said dipperstick and means for pivotally connecting the other end of said longitudinally reciprocable means to said second part, wherein said second slot is adapted to receive said latter means during at least a portion of the relative longitudinal movement of said first and second parts.

5. Apparatus according to claim 3 wherein said second slot is adapted to receive said means for connecting the other end of said second elongate flexible means to said second part during at least a portion of the relative longitudinal movement of said first and second parts.

6. Apparatus according to claim 1 wherein said first longitudinally reciprocable means and said first and second arcuate members are located exteriorly of said first part.

7. Apparatus according to claim 1 wherein said first longitudinally reciprocable means comprises an hydraulically operable cylinder and ram which are located adjacent to one wall of said first part.

8. Apparatus according to claim 1 wherein said first arcuate means comprises a sheave.

9. Apparatus according to claim 1 wherein said second arcuate means comprises a sheave.

10. Apparatus according to claim 1 wherein said first arcuate means comprises a sprocket.

l 1. Apparatus according to claim 1 wherein said second arcuate means comprises a sprocket.

12. Apparatus according to claim 1 wherein said first elongate flexible means comprises a chain.

13. Apparatus according to claim 1 wherein said second elongate flexible means comprises a chain.

14. Apparatus according to claim 1 wherein said first elongate flexible means comprises a cable.

15. Apparatus according to claim 1 wherein said second elongate flexible means comprises a cable.

16. Apparatus according to claim 1 which also comprises third longitudinally reciprocable means for swinging said first part substantially vertically relative to the ground, means for pivotally connecting one end of said third longitudinally reciprocable means to said first support and means for pivotally connecting the other end of said third longitudinally reciprocable means to said first part. i

17. Apparatus according to claim 15 wherein said first longitudinally reciprocable means is positioned at least partially within said means for pivotally connecting said other end of said third longitudinally reciprocable means to said first part.

Claims

1. Telescopic apparatus comprising a first support adapted to be supported in relation to the ground, a first longitudinally extending part pivotally associated with said first support for substantially vertical swinging movement relative thereto, a second longitudinally extending part which is slidable relative to said first part, first longitudinally reciprocable means, means for connecting one end of said first longitudinally reciprocable means to said first part, a first arcuate member, means for rotatably mounting said first arcuate member on the other end of said first longitudinally reciprocable means, substantially in alignment with its longitudinal centerline, first elongate flexible means passing over said first arcuate member, means for connecting one end of said first elongate flexible means to said first part, means for connecting the other end of said first elongate flexible means to said second part, a second arcuate member, means for rotatably mounting said second arcuate member on said other end of said first longitudinally reciprocable means in spaced longitudinal relationship from said first arcuate member and from said first longitudinally reciprocable means and substantially in alignment with the longitudinal centerline thereof, second elongate flexible means passing over said second arcuate member, means for connecting one end of said second elongate flexible means to said first part, means for connecting the other end of said second elongate flexible means to said second part and a device associated with the outer end of said second part, whereby said second part and said device are moved longitudinally relative to said first part upon actuation of said first longitudinally reciprocable means.

4. Apparatus according to claim 3 which also comprises a dipperstick, means for pivotally connecting the dipperstick to the outer end of said second part, second longitudinally reciprocable means, means for pivotally connecting one enD of said second longitudinally reciprocable means to said dipperstick and means for pivotally connecting the other end of said longitudinally reciprocable means to said second part, wherein said second slot is adapted to receive said latter means during at least a portion of the relative longitudinal movement of said first and second parts.

11. Apparatus according to claim 1 wherein said second arcuate means comprises a sprocket.

16. Apparatus according to claim 1 which also comprises third longitudinally reciprocable means for swinging said first part substantially vertically relative to the ground, means for pivotally connecting one end of said third longitudinally reciprocable means to said first support and means for pivotally connecting the other end of said third longitudinally reciprocable means to said first part.