US2784855A - Boom mechanism for digging machines - Google Patents

Description

CLJ

A. w. ACKER 2,784,855

March 12, 1957 BOOM MECHANISM FOR DIGGING MACHINES Filed Sept. l5, 1954 United States BOOM MECHANISM FOR DIGGING MACHINES Alvin W. Acker, Topeka, Kans., assignor to Henry 'Manufacturing Company, Inc., Topeka, Kans., a cor- :poration of Kansas Application September 15, 1954, Seria] No. 456,161

3 Claims. (Cl. 214-438) -vision -o'f a boom mechanism of the class described wherein the length of the boom is automatically increased as it is lowered to its digging position, and decreased as it is raised to its dumping position. This provides for the digging of holes, ditches or the like -t-o a greater depth below the level on which the digging machine is positioned, without at the same time increasing the height of the machine when the 'boom is raised to its dumping position.

'Many similar machines are dangerously top-heavy when the `boom is raised, exerting great stresses on the boom mountings, and being apt to tip over, especially when being transported `over roads at substantial speeds. The arrangement also requires less pow-er to operate the boom, since the boom length, and consequently the moment arm of the load carried thereby, is steadily decreased as the load is raised. The arrangement also permits the digging of vertical-walled holes closer to the digging machine and hence within full View of the operator, since the boom is relatively short when the digging depth is shallow, and progressively lengthens as the depth increases.

Another `object is the provision of a boom mech- -anism of the character described wherein both the raising and lowering of the boom, as well as the lengthening and shortening thereof, is accomplished by a single power unit.

Other objects are extreme simplicity and economy of construction, efficiency and dependability of operation, and adaptability for use with many pre-existing types of digging machines.

With these objects in View, as well as other `objects which will appear in the course of the specification, reference will be had to the drawing, wherein:

Fig. 1 is a side elevational View of Va 'boom mechanism for digging machines embodying the present invention,v

showing lthe `boom and related parts in a raised position in solid lines and in a lowered position in dotted lines, and showing the4 digging bucket in various positions in dotted lines.

Fig. 2 is lan enlarged sectional view taken on line I-Il of Fig. l.

Like reference numerals apply to similar parts throughout the several views, `and the numeral 2 applies to a frame `of any suitable construction which is customarily mounted on a tractor or other supporting vehicle. Said frame may also :be raised a'bove the ground for transportation, -or lowered against the ground, which is indicated at 4, -for added stabilization and support. Said mounting and elevating means, however, form no part of Jthe present invention and `are not here shown. A boomatent 2,784,855 Patented Mar. l2, 1957 supporting standard 6 is carried in a vertical position by frame 2. Said standard is axially oscillat-able on bearing members 8 carried by frame `2, Kand suitable means may be carried by the frame foroscill'ating said standard. However, this feature forms `no part of the present invention and said oscillating means is not shown.

The boom 10 comprises an inner end section `12, and an outer end section 14 telescoped slidably over section 12. Said boom sections are non-circular in cross-sectional shape (square as shown) in order to prevent relativerotation thereof. The inner end Iof sectionlZ is pivotally Iattached lat 16 to a bracket 18 welded or otherwise fixed to standard 6. A hydraulic boom cylinder 20 disposed beneath and parallel to the beam is pivoted `at 22 to a bracket 24 fixed to boom section 12. Said hydraulic cylinder is provided with a piston 26 movable therein, and a piston rod 23 fixed to `said piston and extending forwardly from said cylinder, the outer end of said piston rod being pivoted at 30 to `a bracket 32 weld-ed or otherwise fixed to bo'om`sec'tion 14. Cylinder 2t) is double-acting, the piston 26 therein being movable in either direction by `the delivery of pressure fluid selectively to the hydraulic connections 3dand 36 at either end thereof. A rigid link 38, I-shaped in cross-sectional contour, is pivoted at one end to bracket 32 at 40, and at its `opposite vend to bracket 4Z at 44, bracket 42 `being welded or otherwise fixedvto standard 6 in spaced apart relation below bracket 1S.

A bucket arm 46 is provided intermediate its ends with a bracket 46 fixed thereto, said bracket 'being pivoted `at Si) to the outer end of boom section `M. A bracket 52 is fixed to the upwardly extended end of said bucket arm, and is pivoted at 54s to a piston rod 56 which is attached to a piston 58, movable in a double-acting hydraulic cylinder 66 having hydraulictconnections 62 and `64 xat the ends thereof. Sai-d cylinder is pivoted at 66 `to a 'bracket 63 fixed to boom `section 14 at the inner end thereof.

A :bucket or shovel 76 which opens toward boom `10 is pivoted adjacent its: open side, at '72, to the downwardly extended end of bucket arm 46. A toggle link 74 is pivoted at one end to bucket 70 at the back or closed side thereof, as 'at '76, and at its `opposite end is piV-oted at 78 to one end of link 3%, the `opposite end of link 80 being pivoted at 32 to bucket arm 46 in spaced apart relation above bucket pivot 72. A piston rod 84 is pivotally connected `at 78, and is fixed to a piston. 86 movable in a double-acting hydraulic cylinder 88 provided with hydraulic connections 90 and 92, said cylinder being pivoted at 94 to bracket 52 at the upper end of the bucket arm. The axes of all of the pivots 16, 22, 36, 40, 44, 5t), 54, 66, '72, 76, 78, 82 and 94 are parallel yand generally horizontal. The hydraulic system for energizing each of the cylinders 2t), 66, and 88 is conventional, and is not here shown. ln general, the system comprises suitable pumping and valving means mounted on frame 2 and driven by the engine of the tractor or `other vehicle 4supporting said frame, through suitable driving connections.

ln operation, hydraulic cylinder S8 serves to pivot the bucket 70 with respect to bucket arm 46, acting through toggle-linkage 741-80. Said toggle linkage serves to provide a greater pivotal arc for the bucket with less movement of the hydraulic piston, thus permitting the use of Ia shorter cylinder and promoting economy. Cylinder 60 serves to pivot bucket arm @i6 relative t-o the boom. To lower the boom, iluid is fed to cylinder 20 through fluid connection 36, thereby extending piston rod 28 and lengthening `the boom. Simultaneously, `the piston rod action, acting through link 38, will lower ythe boom pivotally. ln essence, the boom, standard 6?, yand link 38 form a triangular structure, the leg of said triangle formed by standard 6 be fixed and the leg formed by the 'boom being of adjustable length. Thus when the length of the boom is increased `or decreased by cylinder 20, the angularity of the boom Iand link relative to the fixed leg must change. Y

Conversely, when fluid is delivered to cylinder through connection 34, the boom is simultaneously raised and shortened. It is `of course obvious that the actual digging movement `of bucket may be the component result of simultaneous operation of all three cylinders.

Certain advantages of this boom mechanism are believed clear. For example, when starting the digging of v a hole at `ground level, the boom is relatively short, and the bucket is therefore relatively close to standard 6 and hence to the machine operator. As the depth of the hole increases, the length Iof the boom is correspondingly increased. Thus a vertical-walled hole may 'be dug closer t-o the stand-ard, and hence in better po-sition to be viewed by the operator, than would be the case if the boom were of 'a xed length corresponding to the depth ot' the hole to be dug. Also, as the boom is raised and shortened, the moment arm of `the load carried thereby is decreased, thereby decreasing the power necessary to raise the boom and promoting ease of handling. When the boom is fully raised to its dumping or transporting position, its upward extension is at ya minimum. This decreases or eliminates the topheavy nature of many machines of this type.

From an examination of the dotted line position of the boom in Fig. 1, it will be apparent that as the boom reaches its lowermost position, it approaches parallelism with link 38. If it were Iallowed to reach actual parallelism, then -cylinder 20 could not raise the boom, since the lifting force would then 'be axial in link 3S, or dead center. To prevent this, and preserve an `operating angularity between the boom and link 38, piston rod 28 is so proportioned in length that piston Z6 will reach the limit of its travel at the `forward end of cylinder 20, thus arresting the downward movement of the boom, while link 38 is still disposed Iangularly to the boom. if desired, `other stop means could be employed. Also, it is apparent that the degree of extension 1or retraction `of the boom vfor `any given angular movement `thereof depends on the vertical spacing Ibetween pivots 16 and 44, `and could thus lbe altered by setting the bracket 42, which carries pivot 44, at different distances `below bracket 18, or `the setting thereof could be adjustable. These as well as other minor changes or" structure land operation could be made without departing from the spirit of the invention as defined by the scope of the appended claims.

What is claimed as rnew and idesired to be protected by Letters Patent is:

l. In a digging machine, a boom supporting member, a boom comprising a plurality of sections longitudinally movable relative to each other, one end section of said boom being pivoted to said supporting member, digging members carried operatively by the other end section of said boom, a rigid member pivoted at one end to said other Vboom section and at its opposite end to said supporting member in spaced apart rel-ation lbelow said boom pivot, and power means interconnecting the end sections of said boom and operable to extend or retract said boom, whereby said boom is selectively raised `or lowered.

2. In a digging machine, a boom supporting standard, a 'boom comprising inner and outer end sections slidably telescoped for relative longitudinal movement, said inner end section being pivoted to said standard, digging members carried -operatively by said out end section, a hy draulic ram attached at its end respectively to said inner and outer boom sections whereby said boom may be extended or `retract-ed, and a rigid link pivoted at one end to said outer boom section and at its opposite end to said standard at a point spaced below the pivotal connection of said boom to said stand-ard, `whereby said `boom is lowered `as it is extended and raised as it is retracted by said hydraulic ram.

3. The structure as s-et forth in Vclaim 2 wherein said digging members comprise =a bucket arm pivoted to said outer boom section, power means operative t-o pivot said bucket arm, la bucket pivoted to said bucket `arm 'and opening toward said boom, and power means operable to pivot said bucket on said arm.

References Cited in the tile of this patent UNITED STATES PATENTS 2,456,491 Collins Dec. 14, 1948 2,678,741 Pilch M May 18, 1954

Images