Backhoe Mounting Assembly

1. Field of the Invention

The present invention is directed to skid steer vehicles and more particularly to a mounting assembly for securing a backhoe to a skid steer loader.

2. Description of the Prior Art

One of two patents directed specifically to the mounting of a backhoe implement on a skid steer vehicle is U.S. Pat. No. 3,732,996 issued to James J. Bauer on May 15, 1973 and assigned to the assignee of the present invention. The backhoe mounting assembly shown therein is coupled to the frame of the vehicle as well as an implement carrier pivotally mounted on the boom lift arms of the vehicle. In the U.S. Pat. No. 3,732,996 the backhoe mounting assembly is pinned to the frame at a pair of vertically spaced connections provided at the forward end of the frame. The backhoe is substantially supported by the frame in this application and the implement carrier can be disengaged from the backhoe when the backhoe is mounted on the vehicle.

The second U.S. Pat. No. 3,984,016 issued to Patrick Kuhn on Oct. 5, 1976 and assigned to the assignee of the present invention discloses another means of mounting a backhoe. In particular, the mounting means of the U.S. Pat. No. 3,984,016 utilizes the implement carrier and the boom lift arms of the vehicle as more than a mounting and demounting means for the backhoe. Specifically, the device set forth in the U.S. Pat. No. 3,984,016 utilizes the lift arms of the skid steer vehicle as a support means for the backhoe, thereby providing greater mobility of the skid steer vehicle when the backhoe is mounted thereon.

However, it is recognized that there are certain disadvantages in the backhoe mounting assemblies of both of the aforementioned patents. For example, in both of the prior art devices the backhoe mounting assembly includes an operator's space disposed outside the skid steer vehicle. It would be more economical and more advantageous to utilize the operator's compartment of the skid steer vehicle as the operating module of the backhoe. Such an arrangement would place the operator within the confines of the overhead guard overlying the operator's compartment of the skid steer vehicle as well as eliminate the need for an extra operating seat mounted on the backhoe. Such an arrangement offers more protection to the operator and makes the backhoe less bulky, less complex and less expensive.

Unlike the prior art, the present invention defines a separate backhoe mounting frame which operates as an intermediate connection between the vehicle and the backhoe. That is, in each of the prior art patents discussed the backhoe and its mounting assembly was a self-contained unit, with various modifications made in the skid steer vehicle to accommodate the mounting thereon of the backhoe assembly. In the present invention a separate backhoe mounting frame is provided. Thus, the vehicle can remain standard with a first set of standard mounting surfaces between the vehicle and the mounting frame and a second set of standard mounting surfaces between the mounting frame and the backhoe attachment. If minor modifications are required in the backhoe mounting frame to accommodate any change in the design of the basic backhoe, the mounting frame can be modified without changing the skid steer vehicle or the connecting points between the vehicle and the mounting frame.

The present invention provides a backhoe mounting assembly, including a backhoe mounting frame secured to a skid steer loader, said mounting frame in turn mounting and securing a backhoe thereon. The skid steer loader may be similar to the vehicle disclosed in U.S. Pat. No. 3,866,700 issued to James J. Bauer on Feb. 18, 1975 and assigned to the assignee of the present invention. In the present invention the backhoe mounting frame is secured to the vehicle at an upper mounting point by a backhoe mounting bracket specially mounted on the vehicle and at a lower mounting point by an implement carrying apparatus carried at a forward end of the boom lift arm assembly of the vehicle. The sequence associated with the mounting of the backhoe mounting assembly onto the vehicle is similar to that shown in FIGS. 7, 8, 9, and 10 of U.S. Pat. No. 3,984,016 and described in columns 3 and 4, lines 62 to 68 and lines 1-24 of that patent. To the extent that they further the understanding of the present invention, the above-mentioned portions of the U.S. Pat. No. 3,984,016 are herein incorporated by reference. In addition, the seat rails supporting the operator's seat have been extended to enable the backhoe operator to move substantially forward in the operator's compartment to oversee the operation of the backhoe.

The backhoe mounting frame comprises a base structure which is slightly less wide than the distance between the boom arms and slightly higher than the fender of the vehicle. Hand rails provided on the frame extend above the base generally to the height of the skid steer vehicle. However, the base is relatively short from front to rear as viewed from the side of the vehicle. Extending rearwardly from an upper portion of the base is a beam which engages the mounting bracket provided on the skid steer vehicle at the upper mounting point of the frame. A locking mechanism provided on the mounting bracket engages the beam of the mounting frame to lock it in place at the upper mounting point. A lateral projection of the mounting beam extends outwardly to engage an upper side of the boom lift arm so as to immobilize the lift arm. The mounting frame also includes a lower member provided on the base which includes means for engaging the implement carrying apparatus of the boom assembly of the skid steer loader at the lower mounting point of the frame. A protective strut provided at the lower end of the mounting frame engages the implement carrying apparatus so as to lock out the tilt cylinder associated therewith. Associated coupling means secure the backhoe to the mounting frame to complete the assembly.

A more detailed description of the specific embodiment of the present invention is set forth below. Such description, when considered with the accompanying drawings, should enable the reader to have a clearer understanding of the present invention. The drawings may be briefly described as follows:

FIG. 1 is a side elevational view of a skid steer loader having the backhoe mounting assembly secured in place and the backhoe mounted thereon, the forward portion of the backhoe being broken away for clarity and because it does not form a part of this invention;

FIG. 2 is a schematic view showing portions of the backhoe mounting assembly in their relative positions on the vehicle, the general outline of the vehicle being shown in phantom lines;

FIG. 3 is a side elevational view wherein the schematic representation of the vehicle shown in FIG. 2 is represented in slightly smaller scale and the backhoe mounting frame with the backhoe connected thereto is shown as mounted in place on the vehicle.

FIG. 4 is an enlarged side elevational view of a lower mounting point for the connection between the mounting frame and the vehicle, with portions thereof removed for clarity.

FIG. 5 is an end elevational view, looking to the left of the backhoe assembly set forth in FIG. 3, the backhoe itself being removed from the assembly for clarity; and

FIG. 6 is a sectional view taken along the lines 6--6 of FIG. 2.

A skid steer vehicle for mounting the preferred embodiment of the present invention thereon is shown in FIG. 1 and comprises the following parts as set forth below.

The skid steer vehicle 10 includes a body portion or frame 12 having uprights or stanchions 14 mounted at the rear thereof on opposite sides of the body portion 12. An engine (not shown) is mounted on the frame 12 at the rear of the vehicle 10 between the uprights 14, and the engine is protected by a rear enclosure including the rear door 16. The engine propels the vehicle as well as provides power for a hydrostatic drive means which controls the wheels of the vehicle. The drive means for the vehicle may take the form of the means set forth in the above-mentioned U.S. Pat. No. 3,866,700 or similar and includes hydrostatic motors driving separate chain and sprocket drives for independently controlling sets of wheels 18 provided on opposite sides of the vehicle 10. Independent hydrostatic controls for each set of drive wheels 18 permits the skid steer operation of the vehicle 10.

The skid steer vehicle 10 includes a boom assembly 20 comprising a pair of boom lift arms 22 pivotally mounted on respective uprights 14 at their upper ends on mounting points 24. The boom lift arms extend downwardly from the uprights 14 to overlie the front wheels 18 of the vehicle and extend downwardly forward thereof. Hydraulic lift cylinders 24 on opposite sides of the vehicle are pivotally mounted between each upright 14 and a respective lift arm 22 and are used to raise and lower the boom lift arms 22 for loading applications. The lift arms 22 have mounted at a forward end thereof an implement carrying apparatus 25 which can carry a variety of implements but in the present application carries a backhoe mounting frame 29. The apparatus 25 (FIGS. 3 and 4) includes a generally triangular upper edge 25a and a downwardly sloping lower edge 25b. A mechanically actuated wedge 27 is provided adjacent the lower edge 25b. A tilt cylinder 28 is disposed between the boom assembly 20 and the apparatus 25. A cross-tube 25c extends the width of the apparatus 25 and cooperatively engages the frame 29 as will be described below. The vehicle 10 also includes an operator's compartment enclosed by an overhead guard 30. The operator's compartment contains a seat 32 (FIG. 2) as well as operating levers 34 for controlling the opposite sets of wheels 18 of the skid steer vehicle for propelling the vehicle.

The backhoe mounting assembly 35 includes the mounting frame 29 as well as mounting hardware secured to the skid steer vehicle. For example, the skid steer vehicle 10 includes seat rails 36 which are bolted to the frame as at forward bolt locations 37a and rear bolt locations 37b. The rails 36 are substantially longer than the standard seat rails for the vehicle, enabling the operator to move the seat to the forward part of the operator's compartment to oversee the operation of the backhoe when it is secured thereto. Mounted on the vehicle frame at opposite sides thereof are symmetric mounting brackets 38, only one of which will be described in detail. The mounting bracket 38 is a somewhat Z-shaped bracket having a first relatively straight base portion 39 which bolts to the inside of a front portion 15 of the frame 12 of the vehicle. A step portion 40 of the bracket 38 extends outwardly laterally to overlie a top fender or flange 17 of the frame 12. The step 40 of the bracket 38 is interposed between the flange 17, of the frame 12 and a lower flange 31a of a side wall 31 of the overhead guard 30. A mounting assembly 42 holds the side flange 17, the step portion 40 and the flange 31a of the overhead guard 30 in assembled relation. An upper leg 44 of the Z-shaped mounting bracket 38 extends generally perpendicularly from the flange 17. Laterally spaced from the upper leg 44 is a second upper leg portion 46. The upper leg portions 44 and 46 and mounting bracket 38 are held in assembled spaced relation by a lower pin 48 and upper pin 50. Pivotally mounted on the upper pin 50 is a locking mechanism 52 connected to the lower pin 48 by a spring 54.

The mounting assembly 42 comprises a rubber cushion 56 having a center opening 57 and an outside groove 58. The outside groove 58 fits into an opening provided in the flange 17 of the body portion 12. Step portion 40 has an opening therein which loosely receives the cushion 56, and a washer 59 is provided between the lower flange 31a and the rubber cushion 56. End washers 60 and 61 provided at opposite ends of the assembly 42 provide contact surfaces for the nut and bolt combination 62a, 62b which completes the assembly 42.

The mounting frame 29 is best seen in FIGS. 1, 3 and 4. The mounting frame 29 has a base portion 63. The base portion 63 includes a pair of laterally spaced vertical beams 64 which are generally disposed adjacent the inner edges of respective lift arms 22 of the vehicle and aligned with the mounting brackets 38 provided on the vehicle frame. Provided at the respective upper ends of the beams 64 are rearwardly extending support beam 65 which are generally perpendicular to the vertical beams 64. Beams 64 and 65 are channel shaped members fixedly secured together at their respective intersections. A cross-angle 66 secures the laterally spaced beams 64 together at a forward upper portion thereof.

Provided at the rear end of each channel 66 is a pin 67 which engages a slot 68 provided in each mounting bracket 38. The pins 67 comprise an upper mounting point for the frame 29 on the vehicle 10. Each locking member 52 has a slot 70 therein which complements the slot 68 provided on the mounting bracket 38. The outer edge of slot 70 is defined by an extension 71 of the locking member 52, the extension having an inner concave surface 71a and an outer convex surface 71b. Engagement of the pin 67 with the surface 71b of the extension 71 moves the member 52 out of the way to permit the pin 67 to be received in the slot 68. The member 52 can then be closed to retain the pin 62 in fixed relation with the mounting bracket 38. Each pin 67 has a lateral extension 72, best seen in FIG. 5, which extends outwardly of the member 66 to engage an upper surface of a respective boom lift arm 22, so as to prevent the arm from being raised when the mounting frame 28 is mounted on the vehicle 10.

A rear plate 69 of the base 63 includes a pair of downwardly sloped edges 69a and 69b adapted for engagement with the implement carrying apparatus 25 at a lower mounting point of the frame 29 on the vehicle 10.

The frame 29 includes an access ladder having a pair of side rails 73 and 74, enabling an operator to mount and de-mount the vehicle. The rail 73 is provided at the rear end of the mounting frame 29 and is slanted toward the vehicle 10. The rail 73 has a lower end 73a attached to a lower portion of the base 63 of the mounting frame 29 and a vertical section 73b. The upper end of the rail 73 is overlapped to form a U-shaped section 73c having an inner rail 73d which extends downwardly to abut the top surface of the beam 66. The front rail 74 of the mounting frame 29 is an elaborately bent piece of tubing which includes a base portion 74a which curves rearwardly to abut the rail 73 at a lower end to form a bottom step for the ladder 72. A vertical extension 74b of the rail 74 forms a companion rail 74b for the rail 73b of the ladder 72. A lateral extension 74c of the rail 74 extends generally horizontally above the front of the mounting frame 29. A continuous section 74d of the rail 74 extends rearwardly generally in alignment with the channel 66 located on the left hand side of the vehicle. The terminal portion 74e of the rail 74 bends downwardly to abut the channel 66 in general alignment with the rail section 73b adjacent the opposite channel 66. A strut 76 extends from a forward end of the left channel 66 to a forward end of the rail section 74d to support the upper end of the rail 74. In addition to bottom step 74a, the ladder includes steps 77 and 78 secured between opposite vertical sections 73b and 74b. The step 77 is merely a piece of rail extending between the rail section 73b and 74b to provide a foothold for the Bobcat operator. However, the step 78 is a generally wider section mounted between the bottom edge of the channel 66 and the side rails 73b, 74b to form a relatively wide top step of the ladder.

The mounting frame 29 provides means for securing the backhoe 80 to the vehicle 10. Respective clevises 81 and 82 of the backhoe 80 engage projections or plates 83 and 84 of the mounting frame 29. Corresponding holes in the backhoe clevises 81, 82 and the frame mounting plates 83, 84 enable pins 85, 86 to be inserted in place to secure the backhoe 80 to the mounting frame 29 at an upper mounting point. Lower backhoe tabs 87, 88 are inserted between corresponding brackets 89 and 90 of the mounting frame 29. Pins 91 and 92 pass through openings in the brackets 89 and 90 and corresponding openings in the tabs 91, 92 to secure the backhoe 80 to the mounting frame 29 at a lower mounting point. The brackets 89 and 90 include rearwardly directed struts 89a and 90a for a purpose described below.

The backhoe 80 may be mounted on the mounting frame 29 as follows:

Brackets 81 and 82 of the backhoe are aligned with plate 83 and 84 of the frame 29 with the pins 85 and 86 thereafter being mounted in place to secure the backhoe 80 to the frame 29 at the upper mounting point. At the lower mounting point tabs 87 and 88 of the backhoe 80 are inserted into brackets 89 and 90 and the respective pins 91 and 92 are inserted in place to secure the backhoe 80 to the frame 29 at the lower mounting point.

With the backhoe 80 mounted on the frame 29, the backhoe assembly 35 may be secured to the vehicle 10 as follows. With lift arms 22 in the fully lowered position shown in FIG. 1 of the drawing, the vehicle 10 may be moved forward until the implement carrying apparatus 25 engages the rear plate 69 of the base 64 of the mounting frame 29 as best shown in FIG. 3. At the lower mounting point the upper triangular edge 25a of the implement carrying apparatus 25 is received under the upper rear edge 69a of the plate 69. The upper edge 25a of the apparatus 25 engages the upper edge 69a of the plate 69, and the tilt cylinder 28 is retracted to rotate the lower edge 25b of the apparatus 25 into engagement with lower edge 69b of the plate 69.

With the mounting assembly engaged at the lower mounting point the tilt cylinder 28 is engaged to rotate the assembly 25 slightly to urge the pins 67 on respective beams 66 into the slots 68 in respective mounting brackets 38 at the upper mounting point. As each pin 67 is urged rearwardly the thrust of the pin 67 urges the locking member 52 upwardly and forces the pin 67 further into the slot 68 on the mounting bracket 38. When the pin 67 has been urged fully to the rear of the slot 68 the locking member 52 has been pushed upwardly and out of the way. The member 52 then is snapped down by the force of the spring 54 to overlie the pin 67 and firmly hold the pin 67 in the slot 68 provided in the mounting bracket 38 and the slot 70 provided at an inner edge of the locking member 52. With the mounting frame in place on the vehicle 10, lateral extensions 72 of the pins 67 prevent the lift arms 22 of the boom assembly of the vehicle 10 from being raised since the pins 67 are firmly locked in the brackets 38 which are themselves mounted on the vehicle frame 12.

The struts 89a and 90a mounted at a lower end of the base 64 extend rearwardly to engage the cross-tube 25c of the implement carrying apparatus 25 to prevent the tilt cylinder 28 from being further extended. The wedge 27 associated with the apparatus 25 is actuated to slide into an opening on the edge 69b to secure the implement carrying apparatus 25 to the base 64 at the lower mounting point. With the backhoe assembly 35 firmly mounted on the vehicle 10 the seat 32 may be moved to an extreme forward position of the rails 36 to permit the vehicle operator to operate the backhoe 80 within the confines of the envelope provided by the overhead guard 30 of the skid steer vehicle 10.

Thus the present invention provides a new and novel means of securing a backhoe to a skid steer vehicle, the attachment means permitting the vehicle operator to control the device while he is within the confines of the envelope of protection provided by the overhead guard. The backhoe assembly of the present invention further provides a distinct backhoe mounting frame permitting uniformity of connections between the backhoe and mounting frame and standardizing vehicle hardware for backhoe operations. Although we have defined a specific embodiment for the present invention it should be understood that equivalent elements can be substituted for the specific structure recited herein without altering the scope of the invention as defined. The present invention is limited only by the scope and content of the claims set forth below.