US3688930A

US3688930A - Extensible dipper stick for backhoe

Info

Publication number: US3688930A
Application number: US130888A
Authority: US
Inventors: John F Shumaker
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-04-05
Filing date: 1971-04-05
Publication date: 1972-09-05
Anticipated expiration: 1989-09-05
Also published as: CA951280A

Abstract

A telescoping backhoe dipper stick assembly comprising inner and outer tubular members having a fluid ram interconnecting the members for lengthening and shortening the dipper stick. The outer tubular member is connected to a backhoe boom while the bucket is connected to the free end of the inner tubular member. A support bracket encircles the outer tubular member and is fixedly secured to the inner tubular member adjacent the free end, with the support bracket defining a fixed pivot for one end of a fluid motor and the opposite end of the fluid motor cooperating with the bucket. The support bracket has hose guide means extending rewardly to prevent the flexible hoses from becoming caught during extension and retraction of the tubular member. The support bracket thus moves with the inner tubular member to maintain the fixed pivot a predetermined distance from the pivot point between the bucket and the inner tubular member.

Description

United States Patent Shumaker [451 Sept. 5, 1972 54] EXTENSIBLE DIPPER STICK FOR BACKHOE [72] Inventor: John F. Shumnker, 802 Sheafier Drive, Mount Pleasant, Iowa 52641 [22] Filed: April 5, 1971 211 App]. No.: 130,888

Related U.S. Application Data [63] Continuation-impart of Ser. No. 19,161, March [52] U.S. Cl ..214/141 [51] Int. Cl. ..E02f 3/74 [58] Field of Search ..2l4/l38, 141

[56] References Cited UNITED STATES PATENTS 3,140,000 7/1964 Pilch ..214/l38 R 3,390,794 7/ 1968 McMullen et a] ..2l4/ 138 R 3,445,015 5/1969 Sampo et al. ..'...2l4/l4l X Primary Examiner-Philip Arnold AttorneyDressler, Goldsmith, Clement & Gordon ABSTRACT A telescoping backhoe dipper stick assembly comprising inner and outer tubular members having a'fluid ram interconnecting the members for lengthening and shortening the dipper stick. The outer tubular member is connected to a backhoe boom while the bucket is connected to the free end of the inner tubular member. A support bracket encircles the outer tubu lar member and is fixedly secured to the inner tubular member adjacent the free end, with the support bracket defining a fixed pivot for one end of a fluid 'motor and the opposite end of the fluid motor cooperating with the bucket. The support bracket has hose guide means extending rewardly to prevent the flexible hoses from becoming caught during extension and retraction of the tubular member. The support bracket thus moves with the inner tubular member to maintain the fixed pivot a predetermined distance from the pivot point between the bucket and the inner tubular member.

17 Claims, 8 Drawing Figures Patented Sept. 5, 1972 5 Shuts-Sheet 1 Patanted Sept. 5,1912 3,688,930

3 Shuts-Sheet 5 FIG.8

EXTENSIBLE DIPPER STICK FOR BACKIIOE REFERENCE TO RELATED APPLICATIONS.

This application is a continuation-in-part of my application Ser. No. 19,161, filed Mar. 13, 1970.

BACKGROUND OF THE INVENTION stick attachment for such devices.

In earth working implements, such as backhoes, it has become customary to provide an extensible and retractable dipper stick assembly which has one end of a supporting member pivoted to a free end of the boom while the extensible member pivotally supports a bucket. The dipper stick assembly is extended and retracted by a fluid ram and the extensible member supports a second fluid ram which cooperates with the bucket for pivoting the bucket about the free end of the second element. One such type of dipper stick assembly is shown in Pilch US. Pat. No. 3,140,000 in which an outer member is pivoted to the boom and an inner member is telescoped within the outer member and has the bucket pivoted to the free end thereof. In such an arrangement it is necessary to provide a slot in the outer member to accommodate connection of the fluid ram to the inner member. The problem with such a construction is that the slot in the outer portion or member weakens the entire assembly thereby reducing the load capacity of the machine.

An alternate to the Pilch construction disclosed in the above mentioned patent is disclosed in US. Pat. No. 3,390,794 which contemplates an extension member extending from the free end of the inner member and slidably guided on the outer member. While this arrangement eliminates the need for the slot in the outer member, the mechanism requires a large number of parts which necessarily increase the cost of the entire dipper stick assembly.

Thus, there still remains a need for a simple and inexpensive mechanism for supporting the one end of a fluid ram which pivots the bucket on an extensible and retractable dipper stick assembly.

SUMMARY OF THE INVENTION The present invention contemplates a digging mechanism adapted for connection to a vehicle and including a boom pivotally supported at one end on the vehicle with a dipper stick assembly pivotally connected to the opposite end of the boom. A bucket is pivoted to the free end of the dipper stick assembly and a bucket fluid ram extends between the dipper stick assembly and the bucket for pivoting the bucket on the dipper stick assembly. The dipper stick includes an outer tubular member pivoted at one end on the free outer member and moves with the inner member. In the illustrated embodiment, the support means is in the form of a sleeve or ring encircling the outer tubular member and has an opening therein which corresponds in cross-sectional configuration to the cross-sectional configuration of the peripheral surface of the outer member. The ring has first and second arms integral end of the boom and telescopingly receiving an inner therewith and extending along opposite sides of the polygonal outer member with the free ends of the respective arms extending towards the bucket connected to the inner member by the pivot pin which also supports the one element of the drive means.

According to another aspect of the invention, the support means orencompassing ring also has integral hose support means that prevent the hoses from becoming entangled or caught on the free end of the outer tubular member as the inner tubular member is extended and retracted. The modified version of the assembly having the hose support means also includes anti-friction plates on the outer surface of the outer member for engagingthe inner surface of the ring. In addition, the peripheral surface of the inner member has a plurality of narrow elongated circumferentially spacedwear strips engaging the inner surface of the outer member.

The support means of the present invention for the remote end of the fluid ram can be formed as a single element at only a nominal cost while still allowing for the use of an integral outer member pivoted on the boom and an inner member telescoped in the free end of the outer member. Such an arrangement considerably increases the load capacity of the dipper stick assembly without appreciably increasing the weight of the overall assembly.

DETAILED DESCRIPTION OF THE SEVERAL VIEWS OF DRAWINGS FIG. 1 discloses a fragmentary side elevational view of a vehicle having a backhoe, incorporating the present invention, supported on one end thereof;

FIG. 2 is an enlarged side elevational view of the dipper stick assembly forming part of the backhoe and constructed in accordance with the present invention;

FIG. 3 is a vertical sectional view taken along lines 3-3 of FIG. 2;

FIG. 4 is a fragmentary side elevational view similar to FIG. 2, showing the dipper stick assembly in its extended position;

FIG. 5 is an enlarged fragmentary plan view of the dipper stick assembly shown in FIGS. 2 and 4;

FIG. 6 is a side elevational view of a slightly modified form of the dipper stick assembly;

FIG. 7 is a view similar to FIG. 6 showing the assembly in the extended position; and

FIG. 8 is a vertical sectional view taken along line 8-8 of FIG. 7.

DETAILED DESCRIPTION While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail two specific embodiments, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiments illustrated.

Referring first to FIG. 1, there is shown a vehicle mounted backhoe having the dipper stick assembly constructed in accordance with the invention incorporated therein. The backhoe assembly includes a swing tower l pivotally supported by pins 12 upon the vehicle or tractor frame for pivotal movement about a vertical axis.

A rigid boom 14 is supported on the swing tower for pivotal movement about a horizontal axis defined by a pin 16 and the pivotal movement is controlled by a fluid ram 18. For this purpose, the fluid ram has one end pivoted by a pin 20 to the swing tower l0 and the opposite end thereof pivoted by a pin 22 to the rigid boom 14 at a point spaced from the pivot pin 16.

The outer end of the boom 14 has a dipper stick assembly 26 pivoted thereon by a pin 28 with the dipper stick assembly 26 being pivoted about the horizontal axis defined by pin 28 through a further hydraulic fluid ram 30 having one end pivoted on a bracket 32 fixed to the rigid boom 14 and the opposite end pivoted by a pin 34 to the dipper stick assembly 26 at a point spaced from the pivot pin 28.

The dipper stick assembly 26 is constructed in accordance with the present invention and will now be described, with particular reference to FIGS. 2 through 5. The dipper stick assembly 26 of the present invention includes an outer rectangular member 40 having the web portion of a U-shaped support bracket 42 fixedly secured to one end thereof, as by welding. The spaced legs of the U-shaped bracket 42 have aligned apertures for receiving the pivot pin 28 aswell as the pin 34. The rectangular or polygonal tubular member 40 is closed at one end by a plate 44 and telescopingly receives an inner tubular member 46 within the open end thereof. The inner tubular member 46 has a rectangular or polygonal cross-sectional configuration substantially identical to but smaller than the cross-sectional configuration of the outer tubular member and is adapted to be extended and retracted by drive means or an extension fluid ram 48. The extension fluid ram or motor 48 includes a cylinder 50 having its head end pivoted at 52 at a location adjacent the closed end of the outer tubular member. The cylinder 50 has a piston rod 52 extending therefrom which is connected through a pin 54 to the inner tubular member adjacent the free end thereof. Thus, extension and retraction of the piston rod 52 through the supply of pressured fluid to the head and rod ends of the cylinder 50'from a source (not shown) will extend and retract the inner tubular member 46 relative to the outer tubular member 40.

The inner tubular member 46 has a bucket 58 vention, the first element or cylinder '64 is supported for movement with the inner tubular member 46 and at all times has a portion thereof in overlapping relation with the outer tubular member 40. The support means or bracket means for the remote end of the first element of the fluid ram 62 completely encompasses the outer tubular member 40 and likewise at all times encompasses the overlapping portions of the inner and outer tubular members. In this manner, the bracket or support means for the cylinder 64 further adds to the rigidity of the

telescoping members

40 and 46 even when the telescoping members are in the completely extended position.

The support or bracket means of the invention includes a support portion or ring 72 which has an inner opening that corresponds in cross-sectional configuration to the cross-sectional configuration of the polygonal outer tubular member 40. The ring or sleeve 72 has a pair of ears or lugs 74 extending from the upper horizontal wall thereof and respectively receive the pins 76 of a trunion 78 to pivotally support the cylinder 64. Preferably, the inner surface or opening of the sleeve or ring 72 has spaced anti-friction pads 80 to reduce the wear on the adjacent surfaces during relative movement thereof.

The bracket means 70 further includes first and second arms 82 with one end of each of the arms being integral with the forward end of the'ring or sleeve 72. The arms are located on opposite sides of the outer tubular member 40 and extend from the supportportion 72 towards the bucket 58 with the opposite free ends of the respective arms being in juxtaposed relation to the inner tubular member throughout its length. The opposite free ends of the respective arms 82 are interconnected with the inner tubular member by the pivot pin 54 defining the connection for the piston rod 52 to the inner tubular member.

To complete the operative connection of the fluid ram or motor 62 to the bucket 58, the piston rod 66 is operatively connected to the bucket through linkage means 86 consisting of

links

88 and 90, respectively, having their adjacent ends pivotally connected to the free end of the piston rod 66 through a pin 92. The opposite end of the link 88 is connected by a pin 94 to the bucket 58 at a point spaced from the pivotal connection 60. According to another aspect of the present invention, the opposite end of the link 90 is connected to the inner tubular member by the pivot pin 54 so that the fluid ram 48, the arms 82 and the respective links 90 are all connected to the inner member by a common connection. This arrangement necessitates the formation of only one pair of openings in the inner tubular member for connecting all of the respective parts thereto which considerably increases the integrity of the entire unit in its assembled condition. Also, connecting the links 90 to the inner tubular member by a connection which also forms the connection for the arms 82 will result in further rigidity of the entire assembly. With this arrangement, the bracket means 70 define spaced connection points for the bucket tilting a pair of transversely spaced anti-friction rollers 100 supported at axially spaced points on a shaft 102 which is in turn supported for rotation on lugs I04 carried by the respective tubular members.

A slightly modified form of dipper stick assembly is shown in FIGS. 6-8 and in most respects is similar to the construction disclosed and described in connection with FIGS. 1-5. The modified form of the invention utilizes another type of anti-friction means between the inner and outer tubular members as well as between the cylinder support ring and the outer tubular member. In addition, the cylinder support means further includes hose guide means that prevent entanglement of the hoses leading to the bucket fluid ram.

Referring to FIGS. 6 and 7, the dipper stick assembly 26a again includes an outer tubular member 40a, an

. inner tubular member 460 that are extended and retracted relative to each other by a fluid ram 48 (FIG. 8). The outer tubular member 40a is again connected to the boom 14 by a pair of plates 120 (one being shown) fixedly secured to opposite sides of the tubular member 40a and extending below the lower surface thereof.

The plates 120 have apertures for receiving the pivot pins 28 and 34 for the boom 14 and the fluid ram 30.

The bucket 58 is again pivotally supported on the outer end of the inner tubular member by a pivot pin 60 and is pivoted between two extreme positions by hydraulic linkage including the fluid ram 62 having its piston rod 66 operatively connected to the bucket through the compound linkage 86.

The cylinder 64 of the fluid ram 62 is again supported for movement with the inner tubular member 46a by bracket or support means that includes a ring 122 encompassing the outer tubular member and having an inner opening that substantially corresponds in cross-sectional configuration to the cross-sectional configuration of the polygonal outer tubular member 400. The ring has a pair of upstanding ears 124 that extend from the upper horizontal wall and respectively receive the pins 76 of the trunion 78 that pivotally supports the cylinder 64.

The bracket or support means further includes a pair of arms 126 (one being shown in FIGS. 6 and 7) that are integral with the forward edge of the ring 122 and are pivotally connected to the outer end of the inner tubular member through the pivot pin 54 that defines the pivotal connection for the piston.52 and links 90 to the inner tubular member. In addition, the arms 126 have upstanding integral projections 128 that define knock out stops for the cooperative connection between the piston rod 66 and the bucket 58. For this purpose, the upwardly extending projections 128 are located in the path of movement of pin 92 that interconnects

links

88, 90 and the piston rod 66.

According to another aspect of the present invention, the support or bracket means shown in FIGS. 6-8, further includes hose supporting or guide means integral with the ring or sleeve 122 and extending away from the free end of the inner tubular member 46a; The

its downwardly directed legs located on opposite sides of the outer tubular member to assist in guiding the cylinder support means while the tubular members are extended and retracted.

The channel member has a pair of rings 144 connected thereto adjacent the end 142 and the rings are located along the outer edges of the channel member, as more clearly shown in FIG. 8. Flexible hoses 146 extend through the center opening in each of the rings and respectively have one end in communication with opposite ends of the cylinder 64. The opposite ends of each of the flexible hoses 146 are connected through a coupling 148 to one end of substantially rigid conduits 150 that areheld in substantially fixed positions relative to the opposite sides of the boom 14 by brackets 152 (only one being shown).

The rings 144 and brackets 152 are arranged such that the portion of the hoses 146 between the rings and brackets are at all times located on opposite sides of the outer tubular member 46a, more specifically the plates 120.

In the modified embodiment of FIGS. 6-8, the antifriction rollers have been eliminated and the anti-friction means between the inner and outer tubular members consists of a plurality of narrow elongatedwear strips 150 secured to the outer periphery of the inner tubular member 46a at circumferentially spaced locations with the exposed surfaces of the wear strips engaging the inner surface of the outer tubular member. The wear strips 150 are preferably formed of aluminum and are welded or otherwise fixedly secured to the inner tubular member. In addition, the support for the ring 122 is in the form of upper and lower wear plates 152 that are welded to the upper and lower sides of the outer tubular member and are in extended engagement with the upper and lower portions of the wall defining the opening in the ring.

The operation of the modified form of the invention is substantially identical to that described in connection with the embodiment of FIGS. 1-5. However, certain features incorporated into the modified form of the invention have the advantage of considerably increasing the service life of the fluid rams 50 and 62. An inspection of FIG. 6 shows that the rear edge of the ring or sleeve 122 engages the forward edge of the plates 120 to define the fully retracted position for the

tubular members

40a and 46a. In this position, the piston rod 52 is not completely fully retracted within the cylinder 50. Also, in the extended position, the support ring 122 engages the rear edge of a fixed stop that is bolted or otherwise secured to the upper forward edge of the outer tubular member. Again, in its fully extended position, the fluid ram 48 is not fully extended, or stated another way, the pistonconnected to the piston rod 52 has not bottomed out against the rod end of the cylinder 50. This arrangement considerably increases the service life of the fluid ram 40a.

Likewise, the fluid ram 62 also is not in the fully retracted and fully extended positions when the bucket is in the extreme pivoted positions. This is accomplished by engaging the knock out stops 128 with the pin 92 before the piston rod 66 is fully retracted in the cylinder 64. In its extended position, the hydraulic linkage, more specifically the link 90, engages the pivot pin 60 along its forward edge and defines the maximum pivoted position for the bucket before the piston, connected to the piston rod 66, bottoms out against the rod end of the cylinder 62.

In both embodiments of the present invention, the dipper stick assembly has all the attendant advantages of having completely closed integral inner and outer tubular members that are telescoped relative to each other while the bucket tilting means is substantially entirely supported by the inner tubular member through the use of a single integral bracket. The single integral bracket also has hose guide means forpositively guiding the hoses for the tilt fluid ram while the tubular members are moved relative to each other. As can be appreciated from an inspection of the drawings, the sin- .gle bracket may readily be formed without the necessity of machining various elements to close tolerances and the bracket provides an integral connection between opposite ends of the fluid ram 62.

lclaim:

l. A digging mechanism adapted for connection to a vehicle comprising a boom; a dipper stick pivotally connected to one end of said boom; a bucket pivotally connected to a free end of said dipper stick and a fluid ram having extensible and retractable elements respectively cooperating with said dipper stick and said bucket for pivoting said bucket on said dipper stick, the improvement of said dipper stick including an outer tubular member pivoted to said boom; an inner tubular member telescoped within said outer tubular member and having said bucket pivoted on the free end thereof; drive means for extending and retracting said inner member relative to said outer member; and support means for one of said elements, said support means encompassing said outer member and connected to said inner member whereby said support means moves with said inner member.

2. A digging mechanism as defined in claim 1, in which said support means comprises a sleeve encircling said outer tubular member, said sleeve having an opening corresponding in configuration to the peripheral surface of said outer member.

3. A digging mechanism as defined in claim 2, in which the connection to said inner member includes an arm extending beyond an end of said outer tubular member and in juxtaposed relation to said inner tubular member and means for interconnecting said arm and said inner tubular member.

4. A dipper stick having first and second telescoping members, one of said members adapted to be pivoted on one end of a boom and the other of said members having a bucket pivoted on the free end thereof; and fluid motor means having first and second elements for pivoting said bucket, the improvement of bracket means connected to said other of saidmembers and having a support portion surrounding said one of said members, with one of said elements connected to said support portion,,the other of said elements cooperating with said bucket whereby said support portion moves with said other of said members during telescoping movement of said members.

5. A dipper stick as defined in claim 4, in which said members are polygonal in cross-sectional configuration; and said support portion has a corresponding cross-sectional configuration.

6. A dipper stick as defined in claim 5, in which said bracket means includes an arm extending from said support portion towards said bucket, said arm being connected to said other of said members adjacent said free end.

7 A dipper stick as defined in claim 4, in which said one of said members is an outer polygonal tubular member and said other of said members is an inner polygonal tubular member, and in which said dipper stick includes a cylinder and piston rod within said members and respectively having free ends connected to said outer and inner tubular members, the further improvement of said support portion comprising a corresponding polygonal ring surrounding said outer tubular member and said bracket means including first and second arms fixed to said ring and extending towards said bucket, said arms having free ends connected to said inner tubular member whereby extension and retraction of said piston rod will cause said ring to move with said inner tubular member.

8. A digging mechanism adapted for connection to a vehicle and comprising a boom; a dipper stick assembly including an outer, rectangular tubular member pivotally connected at one end to said boom, an inner, rectangular tubular member telescoped in said outer tubular member, and a first fluid ram within said tubular members and having opposite ends respectively connected to said outer and inner tubular members for extending and retracting said inner tubular member; a bucket pivotally supported on the outer end of said inner tubular member; bracket means including first and second arms located on opposite sides of said tubular members and having opposite ends, one end of said arms being connected to said inner tubular member adjacent said outer end, and a ring encompassing said outer tubular member and integral with said opposite ends of said arms; and a second fluid ram having one end supported on said ring and an opposite end operatively connected with said bucket for pivoting said bucket whereby said ring will support said second ram a predetermined distance from the pivot for said bucket and said support will move with said inner tubular member.

9. A digging mechanism as defined in claim 8, including the further improvement of antifriction means on the opposite overlapping ends of said tubular members, said antifriction means respectively engaging a juxtaposed surface of the adjacent tubular member.

10. A digging mechanism as defined in claim 8, including the further improvement of linkage means pivoted on said opposite end of said second ram to said inner tubular member and said bucket at points spaced from the pivotal connection between said bucket and said inner tubular member; and in which said first fluid ram, said one end of said arms and'said linkage means are connected to said inner member by a common connection.

11. A digging mechanism as defined in claim 8, further including a channel member extending from said ring and having a free end terminating adjacent said one end of said outer member when said members are in a retracted'position; and hose receiving rings connected to said free end of said channel member.

12. A digging mechanism as defined in claim 8, further including a limit stop secured to said outer tubular member adjacent its opposite end, said limit stop being disposed in the path of movement of said ring during extension of said inner member and defining the maximum extended position for said inner member.

13. A digging mechanism as defined in claim 8, in which said arms have integral projections disposed in the path of movement of said operative connection between said bucket and said second fluid ram for limiting the extent of retraction of said second fluid ram.

14. A digging mechanism as defined in claim 8, including the further improvement of anti-friction means between said tubular members consisting of narrow elongated wear strips secured to the outer periphery of said inner tubular member at circumferentially spaced locations; and wear plates on the outer periphery of said outer tubular member engaging an inner surface of said ring.

15. A digging mechanism as defined in claim 8, in which said first fluid ram is between fully extended and retracted positions when said tubular members are in their fully extended and fully retracted positions and said second fluid ram is between fully extended and retracted positions when said bucket is in either of two extreme positions.

16. A digging mechanism as defined in claim 2, further including hose guide means integral with said sleeve and extending away from said free end of said inner tubular member.

17. A dipper stick as defined in claim 4, in which said bracket means includes a hose supporting means connected to said support portion, said hose supporting means extending away from said bucket having hose receiving rings on the free end thereof.

Claims

1. A digging mechanism adapted for connection to a vehicle comprising a boom; a dipper stick pivotally connected to one end of said boom; a bucket pivotally connected to a free end of said dipper stick and a fluid ram having extensible and retractable elements respectively cooperating with said dipper stick and said bucket for pivoting said bucket on said dipper stick, the improvement of said dipper stick including an outer tubular member pivoted to said boom; an inner tubular member telescoped within said outer tubular member and having said bucket pivoted on the free end thereof; drive means for extending and retracting said inner member relative to said outer member; and support means for one of said elements, said support means encompassing said outer member and connected to said inner member whereby said support means moves with said inner member.

4. A dipper stick having first and second telescoping members, one of said members adapted to be pivoted on one end of a boom and the other of said members having a bucket pivoted on the free end thereof; and fluid motor means having first and second elements for pivoting said bucket, the improvement of bracket means connected to said other of said members and having a support portion surrounding said one of said members, with one of said elements connected to said support portion, the other of said elements cooperating with said bucket whereby said support portion moves with said other of said members duriNg telescoping movement of said members.

7. A dipper stick as defined in claim 4, in which said one of said members is an outer polygonal tubular member and said other of said members is an inner polygonal tubular member, and in which said dipper stick includes a cylinder and piston rod within said members and respectively having free ends connected to said outer and inner tubular members, the further improvement of said support portion comprising a corresponding polygonal ring surrounding said outer tubular member and said bracket means including first and second arms fixed to said ring and extending towards said bucket, said arms having free ends connected to said inner tubular member whereby extension and retraction of said piston rod will cause said ring to move with said inner tubular member.

10. A digging mechanism as defined in claim 8, including the further improvement of linkage means pivoted on said opposite end of said second ram to said inner tubular member and said bucket at points spaced from the pivotal connection between said bucket and said inner tubular member; and in which said first fluid ram, said one end of said arms and said linkage means are connected to said inner member by a common connection.

11. A digging mechanism as defined in claim 8, further including a channel member extending from said ring and having a free end terminating adjacent said one end of said outer member when said members are in a retracted position; and hose receiving rings connected to said free end of said channel member.