Removable counterweight mounting mechanism

Abstract

A construction machine having a platform rotatable thereon and supporting a boom is disclosed herein. A counterweight is removably secured to the platform by mounting means that includes a pair of bearing hangers received in recesses in the counterweight with removable pins extending through counterbores in the counterweight and openings in the bearing hangers. Adjustable positioning means on the platform engage the counterweight to accurately align the counterbores and the openings. The construction machine also includes hydraulic rams that are carried by the platform and have hooks on extensible elements which receive permanent cross pins located in the recesses so that the hydraulic rams can be utilized to raise and lower the counterweight with respect to the platform.

Description

BACKGROUND OF THE INVENTION

Many construction machines, such as excavators, have a boom which is pivotally supported about a horizontal pivot axis on a turntable or platform which in turn is rotatable about a vertical axis on a support vehicle. Since the load that is supported on the outer end of the boom will tend to tip the vehicle, it is customary to incorporate counterweights which are attached to the platform on the side opposite that of the boom to counteract the weight of the load.

Many of these construction machines are designed to be transported over roadways from one location to another. Because of the legal weight limitations placed on roadways, it has become necessary to support the counterweight on the machine in a manner to permit removal and transportation by a separate vehicle. For this purpose, various types of removable counterweights have been proposed and examples of these are shown in Lonngren, U.S. Pat. No. 3,251,479 and Grider, U.S. Pat. No. 3,375,021.

Most of the support mechanisms that are in existence today for removable counterweights require various types of complicated linkage mechanisms and/or numerous bolts and other type of hardware for holding the counterweight in a fixed position on the platform. Many of these devices require accurate alignment of various openings for receiving the bolts or pins which makes it difficult because the counterweight is usually formed from some type of casting material which is normally not flat and smooth. This in many instances requires machining of the counterweight after it has been formed which increases the overall cost of the unit.

SUMMARY OF THE INVENTION

According to the present invention, a counterweight is supported on a platform with a minimum number of parts that are readily removable and access to these parts is available from the side of the counterweight so that there is little probability of the counterweight inadvertently falling onto a person while it is being removed. The supporting mechanism for the counter-weight includes primary support means consisting of a pair of hangers that are supported on the platform of a construction machine, such as an excavator, having a boom pivoted on the platform or turntable. The respective hangers are received into recesses in the counterweight and the counterweight has counterbores extending from opposite end walls across the recesses while the bearing hangers have openings which are aligned with the counterbores by adjustable positioning means so that support pins can readily be inserted and removed with a minimum amount of effort. The hangers and counterbores are positioned so that the removable pins are located between the platform and the center of gravity for the mass of the counter-weight so that the counterweight tends to swing towards the platform to its finally fixed position. The counterweight can be held in this fixed position by one or more removable bolts.

The counterweight can readily be removed from the machine by hydraulic rams that are connected to the platform and have hooks on the ends of the extensible elements which are capable of being received into the recesses and receive permanent pins located in the recesses so that the counterweight can be raised and lowered by the hydraulic rams. However, once the counterweight is in the connected position, the hydraulic rams form no part of the support for the counterweight on the platform.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 shows a side elevational view of a construction machine, such as an excavator;

FIG. 2 is an enlarged end view, as viewed along line 2--2 of FIG. 1 showing the counterweight and part of the support structure;

FIG. 3 is a vertical section as viewed along line 3--3 of FIG. 2;

FIG. 4 is a fragmentary vertical section as viewed along line 4--4 of FIG. 2; and

FIG. 5 is a fragmentary sectional view as viewed along line 5--5 of FIG. 3.

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 a preferred embodiment of the invention, 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 embodiment illustrated.

FIG. 1 of the drawings discloses a construction machine 10, such as an excavator, which may have the present invention incorporated therein. The excavator may be of the type disclosed in U.S. Pat. No. 3,680,722, assigned to the assignee of the present invention.

Excavator 10 includes a vehicle or support 12 for supporting a turntable 14, which is rotatable about a vertical axis. Turntable 14 has a boom 16 pivotally supported for movement about horizontal pivot pin 18 and the outer end of boom 16 supports an excavating device 20.

As was indicated above, because the center of gravity of the load supported by boom 16 is located a substantial distance from the center of turntable or platform 14, it is customary to secure a counterweight at a position approximately 180.degree. from the boom connection so that the boom extends in one direction while the counterweight extends in an opposite direction with respect to the center of the platform.

According to the present invention, the counterweight is removably supported on the platform or turntable in such a manner that it can readily be removed from the platform and lowered onto a transport vehicle so that the counterweight and construction machine can be transported separately.

The primary support for the counterweight on the platform consists of a pair of pins that are accessible from the side of the counterweight so that the unit can easily be removed. The pins are positioned so that the weight of the counterweight will tend to swing or pivot the counterweight about the pins towards the platform. Additional secondary securing means may then be used to prevent any swinging movement of the counterweight during use of the implement.

Referring again to FIG. 1, there is shown a counterweight 30 that is supported on platform 14. For this purpose, platform 14 (FIG. 3) has a substantially vertical portion 32 defining a substantially vertical wall 34 having a pair of transversely spaced horizontally extending arms 36 at the upper end thereof. A pair of brackets or bearing hangers 38 extend from vertical wall 34 at transversely spaced locations and each of the bearing hangers has an opening 40 therein. Openings 40 may have bushings 42 located therein for supporting a pin that will be described later.

Brackets 38 are received into transversely aligned recesses 44 that extend from one corner of counterweight 30. Counterweight 30 also has a pair of bores 46 which extend from the respective end walls 48. As shown in FIG. 5, bores 46 each have an enlarged portion 50 adjacent end wall 48 and a reducing portion 52 which extends across recess 44 and has a tapered portion therebetween. Recesses 44 have outwardly tapering wall portions 45 at the upper ends for a purpose that will be described later.

The primary support means for counterweight 30 also includes removable pin means that are received into bores or counterbores 46 and extend through openings 40 in hangers 38. According to one aspect of the invention, removable pin means 54 are designed to substantially reduce the weight required to be manipulated during removal and attachment of counterweight 30 to turntable 14. It will be appreciated that the size of the pins must be substantial in order to support the large mass that is embodied in the counterweight. For example, the pins may be on the order of two to three inches in diameter so that a long pin, several feet in length, would be extremely heavy and difficult to manipulate. To overcome this problem, each removable pin means 54 has a first portion or pin 56 that is substantially equal in diameter to the diameter of reduced portion 52 of the counterbore 46 so as to produce a tight fit in counterbore 46 as well as in bushing 42 that forms part of opening 40. However, the remainder of the removable pin means 54 is substantially smaller in size and acts as a handle portion 58. Since the handle portion 58 does not support any of the weight and thus is not a functional part of the support, handle portion 58 can be formed from a thin rod and have a gripping portion at the outer end thereof. Preferably, removable pin means 54 is releasably retained in counterbore 46 by suitable latch means (not shown) to prevent inadvertent removal during operation of the vehicle.

The primary support means so far described is sufficient to support the entire weight of the counterweight in a substantially fixed position with respect to turntable 14. An inspection of FIG. 3 reveals that the removable pin means 54, more specifically the pin portion 56, is located adjacent one upper inner corner of the counterweight, as viewed with respect to the turntable 14. This will locate the center of gravity of the counterweight outside or to the right, as viewed in FIG. 1, of support means consisting of brackets or hangers 38 and movable pin means 54. Thus, the counterweight will tend to swing or pivot against vertical wall 34 and be held there by the weight or mass of the counterweight.

To further insure that the counterweight does not swing about the movable pin 56, it is desirable to have secondary support means or releasable bolt means between the counterweight and the platform. While any number or type of bolt means may be utilized, two have been illustrated in the preferred embodiment. Each releasable bolt means 60 (FIGS. 4 and 5) consists of a bolt 62 which extends through an enlarged opening 64 adjacent the lower end of vertical wall 34 with a nut 66 and a washer 68 at the outer end of bolt 62. Bolt 62 extends through a slot 70 extending from bottom wall 72 of counterweight 30.

According to another aspect of the invention, counterweight mounting means also includes adjustable positioning means to accurately position the counterweight with respect to the platform or turntable. It will be appreciated that when the counterweight is formed, which is usually done by a casting operation, the exact dimensions and configurations are sometimes difficult to control. For example, the side walls 74 and top wall 76, as well as bottom wall 72 and end walls 48 may not be flat and smooth. This therefore creates problems in accurately aligning openings 40 with respect to counterbores 46 so that removable pin means 54 may be inserted. In most prior art devices, to accomplish this, the operator must continuously manipulate counterweight 30, which is a large mass, until the opening and counterbore are finally aligned. The adjustable positioning means eliminates this problem by defining an accurate fixed position of the counterweight with respect to the platform so that pin means 54 may readily be inserted.

As shown in FIGS. 4 and 5, adjustable position means 80 consists of first and second studs 82 and 84 that respectively, extend through a horizontal wall on arm 36 positioned above top wall 76 of counterweight 30 and vertical wall 34 adjacent the upper end thereof. Studs 82 and 84 have lock nuts 86 thereon so that the position of the free end of the respective studs can be accurately controlled. The free ends of the studs are adapted to engage top wall 76 and side wall 74 of counterweight 30 at a location in close proximity to counterbores 46. Thus, when the counterweight is moved into a position where the walls engage the free ends of studs 82 and 84, openings 40 are accurately aligned with the reduced portion 52 of counterbore 46.

The mounting means for counterweight 30 also incorporates separate means for raising and lowering counterweight 30 with respect to platform or turntable 14. In many instances, the counterweight is removed and mounted at a remote location where the only equipment available is the vehicle itself. To compensate for this feature, many of the prior art units have developed elaborate schemes whereby the counterweight may be removed from the platform or turntable and supported on the vehicle frame so that the turntable can be rotated and the boom utilized for removing the counterweight and transferring it to a transport vehicle. These devices have become extremely complicated, adding to the overall cost of a removable counterweight.

Thus, according to another aspect of the present invention, the mounting means for counterweight 30 also incorporates separate fluid ram means for raising and lowering the counterweight with respect to the turntable. In the illustrated embodiment, the fluid ram means consists of first and second fluid rams 90 that each have cylinders or first elements 92 mounted by trunions 94 on arms 36 so that the fluid rams are aligned with the respective recesses 44 in counterweight 30. The respective cylinders or first elements have piston rods or second elements 96 movable relative thereto with the free ends of piston rod having hooks 98 supported thereon.

As indicated above, fluid rams 90 are aligned with recesses 44 so that at least the piston rods 96 can extend into the recesses. Hooks 98 are adapted to receive pins 100 that extend across recesses 44. These pins are preferably permanently mounted within the counterweight during the casting operation. Thus, the open hooks 98 and the permanent pins 100 again eliminate the need for accurate alignment of the counterweight with respect to the cylinder before the two can be interconnected.

Summarizing the present invention, the unique primary and secondary support means for the counterweight has a number of advantages. First of all the primary support means consists of two removable pins which are readily accessible from the sides or opposite ends of the counterweight so that these may be removed without the operator being underneath the counterweight. Furthermore, the removable toggle bolts 60 can be loosened and pivoted downwardly before the primary support means are removed. This means that the counterweight is fully supported even after the removable bolt means 60 are removed. Also, the primary and secondary support means are the only support for the unit during the operation of the vehicle so that there is no weight or load placed on the fluid ram 90 except when the counterweight is removed or attached.

The adjustable positioning means 80 eliminates the need for any machining operation to insure that the various parts of the counterweight are accurately positioned with respect to platform 14. The relative point contact between the two position adjusting means 80 can easily be adjusted the first time the counterweight is mounted onto platform 14 and thereafter, this accurate alignment for the counterweight with respect to platform 14 remains the same.

Claims

What is claimed is:

1. In combination with a machine having a rotatable platform mounted thereon with a boom pivotally supported for movement about a horizontal pivot on said platform; a counterweight; means defining a recess in said counterweight; a permanent pin extending across said recess; means mounted on said platform for engaging said permanent pin; a bearing hanger on said platform adapted to be received in said recess, said hanger having an opening, said counterweight having end walls with a bore extending from one end wall across said recess, said bore having an enlarged portion adjacent said one end wall and a reduced portion extending across said recess; and removable pin means received into said bore and extending through said opening in said hanger for supporting said counterweight on said platform, said removable pin means including a pin portion corresponding in size to said reduced portion and a handle portion of a different size connected to said pin portion.

2. The combination as defined in claim 1, in which said bore and said removable pin means are located on said counterweight to be positioned between said platform and the counterweight center of gravity so that said counterweight will swing toward said platform when supported by said removable pin means.

3. The combination as defined in claim 2, further including releasable bolt means between said counterweight and said platform for holding said counterweight in a fixed position with respect to said platform.

4. The combination as defined in claim 1, further including adjustable positioning means on said platform, said adjustable positioning means being located so that said bore and said opening are aligned when said counterweight engages said positioning means.

5. The combination as defined in claim 1, further including a second bearing hanger secured to said platform and having an opening therein, said bearing hangers being transversely spaced from each other and in which said counterweight has a second recess aligned with said second bearing hanger and a second bore having an enlarged portion extending from the other end wall and a reduced portion extending across said recess, a second permanent pin extending across said second recess with said means mounted on said platform engaging both permanent pins; and a further removable pin means identical in construction to said removable pin means received in said second bore and extending through said opening in said second bearing hanger.

6. The combination as defined in claim 5 in which said means mounted on said platform includes first and second fluid rams respectively aligned with said recesses, each fluid ram having a first element connected to said platform and a second element, each second element having a hook, said permanent pins being positioned to be received into said hooks on said second elements.

7. The combination as defined in claim 6, in which said platform has a substantially vertical wall with said bearing hangers extending from said vertical wall and said counterweight has a vertical wall extending generally parallel to said vertical wall on said platform, further including adjustable positioning means on said platform and engaging said vertical wall of said counterweight to accurately position said counterweight with respect to said platform.

8. The combination as defined in claim 7, in which each bore has a tapered portion between said enlarged portion and said reduced portion.