US2703633A - One-way brake - Google Patents

Description

March 8, 1955 D. c. GRAY 2,703,633

ONE-WAY BRAKE Filed Dec. 27, 1948 2 Shee'ts-Sheet 1 /Z FJE. 2 I 6 Q 1H; i 0' :q a

i/vvE/vmQ DONALD C. GRAY ATTOIQ/VEY March 8, 1955 D. c. GRAY ONE-WAY BRAKE 2 Sheets-Sheet 2 Filed Dec. 27, l948 I I 1/! I IIlIl/l/ II DONALD o GRAY B) ATTOQNEY United States Patent ONE-WAY BRAKE Donald C. Gray, Rose Township, assignor to American Hoist & tion of Delaware Ramsey County, Minn., Derrick Co., a corpora- This invention has relation to a material handling apparatus constituted as a hoist, and particularly to braking means for controlling operations thereof.

An object of the invention is to provide a simply constructed, efficient, novel and improved hoist which will incorporate features and characteristics adapted to render the hoist reliable in operation.

A further object is to provide a material handling apparatus wherein will be incorporated desirable and improved features and characteristics novel both as individual entities of the material handling apparatus and in combination with each other.

And a further object is to provide a hoist constructed and operative in the manner as hereinafter set forth.

With the above objects in view, as well as others which will appear as the specification proceeds, the invention comprises the construction, arrangement and combination of parts as now to be fully described and as hereinafter to be specifically claimed, it being understood that the disclosure herein is merely illustrative and intended in no way in a limiting sense, changes in details of construction and arrangement of parts being permissible as long as within the spirit of the invention and the scope of the claim which follows.

In the accompanying drawings forming a part of this specification:

Fig. 1 is a plan view of a material handling apparatus made according to the invention;

Fig. 2 is a side elevational view of the material handling apparatus as it would appear from the bottom of the sheet in Fig. 1;

Fig. 3 is an enlarged side elevational view disclosing cooperating elements, one stationary and the other rotatable, of the material handling apparatus as said elements would appear when removed from said apparatus;

Fig. 4 is a vertical sectional view, on a scale larger than in Fig. l and smaller than in Fig. 3, taken on line 4-4 in Fig. l; and

Fig. 5 is an exploded view, on a scale larger than in Fig. 3, disclosing elements of the material handling apparatus in perspective.

With respect to the drawings and the numerals of reference thereon, a base for the material handling apparatus is constituted as spaced apart side frame members, denoted and 11, respectively.

The side frame members 10 and 11 suitably and conveniently support brackets indicated 12 and 13, respectively, which in turn rotatably support a drum shaft 14 of the material handling apparatus.

A drum 15 of the material handling apparatus, in adjacent relation to the side frame member 11 and in spaced relation to the side frame member 10, is suitably and conveniently fixed upon the drum shaft 14 in a manner forming no part of the present invention, and a usual cable on the drum 15, for a boom or the like, is represented 16.

A housing 17, adjacent to and rigid with the side frame member 10, between this side frame member and the drum 15, is adapted to contain a bath of oil.

A worm gear 18 fixed, as at 19, on the drum shaft 14 meshes with a worm 20 integral or rigid with a drive shaft 21 situated in the housing 17 and rotatably supported in spaced apart bearings, indicated 22 and 23, respectively, provided by said housing. The construction and arrangement are such that the bearings 22 and 23 preclude longitudinal movement of the drive shaft 21, and said drive shaft is coupled, as at 24, with the actuated 2,703,633 Patented Mar. 8, 1955 shaft 25 of a motor 26 to be driven thereby, desirably in either direction. The end of the housing 17 opposite the motor 26 in cludes an opening 27 covered by a removable closure member 28 for said housing, and a wall 29 of said housing, also providing the bearing 23, adjacent the closure member 28, rigidly supports, as at 30, a disc element or bushing 31 disposed about and in perpendicular relation to the drive shaft 21 in such manner as to permit free rotation of said drive shaft while said disc element or bushing is retained stationary. The construction and arrangement are such that the disc element or bushing 31 is retained up against the surface of the wall 29 opposite the worm 20 and adjacent the closure member 28.

A thrust element or plate 32, situated at the side of the disc element or bushing 31 opposite the wall 29 and adjacent the closure member 28, is fixedly supported upon the adjacent end portion of the drive shaft 21 in contiguous relation to said disc element or bushing 31. As disclosed, the thrust element or plate 32 is constituted as a flange portion 33 in parallel, contiguous relation to the disc element or bushing 31 and an annular portion 34, at the side of said flange portion opposite said disc element or bushing, snugly slidable on the drive shaft 21. The thrust element or plate 32 is fixed by a key 35 against turning movement relative to said drive shaft, and a nut 36 on an external thread 37 upon the adjacent end portion of the drive shaft is adapted to be turned down against the end of the annular portion 34 of the thrust element or plate 32 thus to cause the flange portion 33 of said thrust element or plate to be retained against the disc element or bushing 31.

The thrust element or plate 32, fixed upon the drive shaft 21 to rotate therewith, includes a smoothly polished working or rubbing surface 38, at the side of the flange portion 33 of said thrust element or plate adjacent the disc element or bushing 31, which lies in a plane passed pler faendicularly through the longitudinal axis of said drive 5 1a 1.

The disc element or bushing 31, rigid with the wall 29 of the housing 17, includes spaced apart, smoothly polished working or rubbing surfaces 39, at the side of said disc element or bushing adjacent the thrust element or plate 32, which lie in a single plane parallel with the plane including the working or rubbing surface 38, and

spaced apart radial grooves between working or rubbing surfaces 39 which are adjacent each other are each indicated 40.

In the illustrated embodiment of the invention, the radial grooves 40 are equally spaced circumferentially about the disc element or bushing 31, and said radial grooves are substantially alike. Each is bounded or defined at one of its sides by a radially extending surface 41 disposed interiorly of said disc element or bushing in perpendicular relation to the plane of its working or rubbing surfaces 39 as disclosed, and at its other side by a radially extending surface 42 disposed interiorly of said disc element or bushing in gradually sloping relation to the plane of said working or rubbing surfaces 39. Stated otherwise, the bounding or defining surface 41 of each radial groove 40 constitutes a steep drop off from one of the working or rubbing surfaces 39 providing therewith a scraping or knife edge 43 extending the full length of the corresponding radial groove, and the bounding or defining surface 42 of each radial groove slants gradually from one of said working or rubbing surfaces 39 interiorly of the disc element or bushing 31 in such manner that the working or rubbing surfaces of said disc element or bushing and the exterior edge portions of said bounding or defining surfaces 42 merge smoothly into each other along the full lengths of the radial grooves. As shown, said radial grooves have depth less than a measurement representing one-half the thickness of the disc element or bushing 31, the interior edges of the steep drop off and gradually sloping surfaces 41 and 42 meet at the bottoms or bases of said radial grooves, and the gradually sloping surfaces 42 all extend away from the steep drop off surfaces 41 of the corresponding radial grooves in the same direction circumferentially of said disc element or bushing.

Cables such as 16 are employed as parts of material handling apparatuses of the general character as hereinbefore illustrated and described to elevate and lower booms, or the like, and/or loads carried thereby. It is highly desirable that no braking action be applied to the actuating mechanisms, including drums such as 1.5, of hoists during intervals of accomplishment of load elevating operations, and that bra-king action be applied to said actuating mechanisms during intervals of accomplishment of load lowering operations, thus to limit drift.

As is well known, the thrust reaction of a load upon the actuating mechanism of a hoist is in a single direction, and is proportional to the weight of the load. In the disclosure as made, the thrust reaction is toward the left in Fig. 4 of the drawings, in direction to cause the smooth working or rubbing surface 38 of the thrust element or plate 32 to be urged into pressing engagement against the smooth working or rubbing surfaces 39 of the disc element or bushing 31.

The construction and arrangement will be such that the thrust element or plate 32 will be rotated, together with the driving shaft 21 as a unit in response to actuation of the motor 26, to cause the working or rubbing surface 38 of said thrust element or plate to be successively slid over the Working or rubbing surface 39 of the disc element or bushing 31 in direction from the steep drop off surface 41 toward the gradually sloping surface 42 of each radial groove 40 during intervals of accomplishing load elevating operations, and to cause said working surface 38 to be successively slid over said working or rubbing surfaces 39 indirection from the gradually sloping surface 42 toward the steep drop off surface 41 of each radial groove during intervals of accomplishing load lowering operations.

The disc element or bushing 31 and the thrust element or plate 32 will be immersed, orpartially immersed, in the bath of oil contained in the housing 17, and when said thrust element or plate 32 is rotated during the accomplishment of load elevating operations, its sliding movement over said disc element or bushing 31 and its radial grooves, in direction from the steep drop off surface 41 toward the gradually sloping surface 42 of each radial groove, will cause buildup of wedges of oil, in the radial grooves 40 and between the thrust element or plate and the disc element 'or bushing. In practice, these wedges of oil separate the working or rubbing surface 38 of the thrust element or plate 32 and the working or rubbing surfaces 39 of the disc element or bushing 31 and cause friction to be reduced to minimum, or a very low, value, depending upon the thrust reaction value, the rate of rotation of said thrust element or plate, etc. the thrust element or plate 32 is rotated during the accomplishment of load lowering operations, its sliding movement over said disc element or bushing 31 and its radial grooves, in direction from the gradual sloping surface 42 toward the steep drop off surface 41 of each '5 radial groove, will cause the scraping or knife edges 43 to wipe or scrape off much of the oil from the working or rubbing surface 38 into the radial grooves 40 so that there will be only a so-called greasy film and high frictional contact between the working or rubbing surfaces 39 and said working or rubbing surface 38. The thrust reaction of the rotatable element 32 against the stationary element 31, itself proportional to the hoist load, will develop a friction torque at the locations of engagement of the working or rubbing surfaces 38 and 39 which is proportional to said hoist load.

It is possible by selected use of materials suitable to be employed in the manufacture of elements such as 31 and 32, and/or by varying proportions of said elements, to obtain friction torque between the surfaces 38 and 39 of greater or less value, as may in particular instances be considered desirable. Actually, the construction and arrangement can be such that the friction torque has value When i sufficient to cause a hoist load to be bodily suspended, thus to make it necessary to employ the motor to drive the load down.

Attention is called to the fact that a thrust element such as 32 could include radial grooves such as 40 in its surface engaged against a disc element such as 31 in an instance when the thrust element engaging surface of the disc element was a-contin-uous surface such as 38. Stated otherwise, the positions of the elements 31 and 32 could be reversed, with the disc element 31 fixed upon the driving shaft 21 to be rotatable therewith, the thrust element 32 rigid with the wall 29, and the surfaces 38 and 39 in adjacent, engaged relation. In such event, the disc elernent 31 would be rotated to cause the working or rubbing surfaces 39 of said disc element to be slid over the working or rubbing surface 38 of the thrust element in direction to cause said working or rubbing surface 38 to be moved from the steep drop off surface 41 toward the gradually sloping surface 42 of each radial groove 40 during load elevating operations, and to be moved from the gradually sloping surface 42 toward the steep drop off surface 41 of each radial groove during load lowerin g operations.

The disc and thrust elements 31 and 32, as well as parts assembled therewith, are fully enclosed, offer substantially no torque in the elevating direction, which would if present assert itself against the hoisting operations, and, in cooperation with each other, are adapted to provide torque in the lowering direction in amount sutficient or requisite to prevent drift, or even to make necessary power actuation lowering of a load.

What is claimed is:

A brake structure comprising a first thrust element in fixed relation to a bearing support and having a Working surface, and a second thrust element rigidly supported upon a shaft rotatably mounted in said bearing support and including a working surface perpendicular to the longitudinal axis of said shaft and adjacent to and lying in a plane parallel to the working surface of said first thrust element to be pressingly engaged against the working surface of the first thrust element in response to end thrust created by reason of a load upon and tending to rotate said shaft, one of said thrust elements including circumferentially spaced, internally disposed liquid rccciving grooves in contiguous relation to its working surface and extending radially of said shaft each bounded at one of its sides by a drop off surface cooperating with the working surface of the thrust element having said liquid receiving grooves to provide a scraping edge at the location of jointure between said drop off and working surfaces and at its other side by a surface sloping relative to the Working surface with which said liquid receiving grooves are contiguous and merging into said last mentioned working surface.

References Cited in the file of this patent UNITED STATES PATENTS 1,092,015 Bryant Mar. 31, 1914 1,738,308 Munier Dec. 3, 1929 1,829,825 Freeman et al Nov. 3, 1931 1,892,940 'Erdahl Ian. 3, 1933 1,971,515 Transue Aug. 28, 1934 2,053,398 Kingsbury Sept. 8, 1936 2,085,815 McCollum July 6, 1937 2,106,862 Wheeler Feb. 1, 1938 2,202,137 Brown May 28, 1940 2,274,427 Miller et al Feb. 24, 1942 2,461,675 Berg Feb. 15, 1949 2,583,140 'Else Jan. 22, 1952 FOREIGN PATENTS 579,061 Germany June 1, 1933

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