US 2685801 A
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D. TIDSH MAN SHEAVE TREAD Aug. 10, 1954 Filed Feb. 28, 1952 HMAN m n mnbrwm E lo V Nm w hA N D Patented Aug. 10, 1954 UNITED STATES PATENT OFFICE 'SHEAVE TREAD David Tishman, Goose Neck Point, N. J. Application February 28, 1952 Serial No. 273,910
1 Claim. 1 This invention relates to sheaves adaptable for cable pulley services and particularly to the tread disposed on the sheave for providing the proper traction with the cable.
Specifically, my invention is an improvement over the sheave known in the industry as the "Neenan type sheave. The Neenan type sheave provides tractive tread composing a mass of fiber rope ends made up into a series of bundles, and treated with tar. The rope ends are placed radially on their respective ends within the channel of the sheave and they are compacted into a hardened tractional tread by compressing the tarred ropes between opposite plates of the sheave.
There were certain inherent disadvantages in utilizing rope for the sheave tread, which were sought to be overcome by the industry. One major disadvantage was the necessity of grooving the rope ends after installation to provide a cable trough, which operation required the use of a special device for the purpose. Another disadvantage resulted in the necessity for removing and replacing the entire tread when only a portion of the tread was damaged or worn, for instance by a cable which was tauter'than its neighboring cable. This, of course, was expensive in material and labor, as well as time consuming in performance of replacement. Another disadvantage with the rope tread was that it was not always impervious to the lubricant carried by the sheave cables, therefore, accelerating deterioration of the tread. The compactness of the tread rope ends was not always uniform since the rope was, of necessity, inserted in bunches and the bunches were compacted with previously installed bunches by manual means. Another disadvantage was that the fibrous rope itself was not as durable a material as might be desired; and still another disadvantage of the rope was the objectionable shedding of rope dust when wear by the cables commenced.
It is the object of my invention to overcome each of the above-mentioned disadvantages by providing a plurality of tread members adaptable for the Neenan type sheave which are easily and separably replaceable, made from a material impervious to cable lubricants, extremely durable, non-shedding, and having preformed grooves on its upper end thereof, to guide and space the cables.
In accordance with my invention there is provided in combination with a sheave having a retaining drum and a locking plate mounted on one side thereof to form substantially a U- shaped channel with the drum, a plurality of tread members radially disposed in juxtaposition on the periphery of the drum and securely mounted within said channel by means of the locking plate. Each of the tread members is a solid, unitary member, shaped to extend the complete lateral length of the channel. The sides of the tread member are shaped to conform with the engaging sides of the channel, and each of the tread members is positioned on its bottom end and radially with respect to the drum axis to completely cover the periphery of the drum.
The above-mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, in which:
Figure 1 is an end view of a sheave, showing part in vertical cross-sectional view;
Figure 2 is a perspective view of a single tread member; and
Figure 3 is a side view of a sheave, part of its edge being broken away to show the radial disposition of the tread members on the periphery of the sheave.
Referring to Fig. 1, there is illustrated a sheave comprising a body portion I, a sleeve or bushing 2, having formed therein a shaft bore 3. A series of spokes are provided for carrying at their outer ends a retaining drum 5. On one side of the drum there is provided a shoulder 6. The inner wall of shoulder B is tapered inwardly at l to form a portion of the retaining channel for the peripheral tread 8. On the opposite side of the drum there is provided a locking gate 9 With a shoulder I 0, also having a tapered inner wall II. The locking plate together with the retaining drum form a channel substantially in the shape of a U, for retaining the tread 8.
The tread portion 8 of the sheave, which forms the basis of my invention, is comprised of a plurality of tread members 12 (Fig. 2). Each tread member has tapered side walls l3 to conform with the tapered walls 1, H of the sheave. The top portion [4 of the tread member I2 is provided with grooves IE to properly separate the sheave cables (not shown). The lateral walls I6 are slightly tapered toward the axis of the drum so that when the plurality of tread members are placed in juxtaposition (Fig. 3), and radially disposed on the periphery of the sheave, they form a continuous and circular surface.
The tread members l2 are preferably made from a durable oil-impervious, partially hard- In placing the tread "members 12" on"'th'e"'pe-" riphery of the drum 5 locking plate 9 is loosened from the portion of the sheave. The tread members are then positioned radially with respect-tow the drum axis on their respective bottom ends on the periphery of the drum. The locking"-plate":
9 is then properly secured on the drum by. meansm of tightening the bolts l8 and nuts I9 "unipressing the tread members. virtue of their tapered sides [3 conforming with The tread membersqzbyin theitapered shoulders I are-thereby retained :sea
curely the channel.
Thus it can readilybe seen that if :one or-morew; tread members'are damaged, they maybe easilym replaced with a .minimum of! time i and material, a
While I have described above'the principlesofc-my invention in connection. with specific ape paratus, .it is .to .be. clearly understood -thatrth-is description is made-only byway-of example and not. as .a limitation totthe scope of my invention as set fo'r-th in-the objects thereof and :in the ac companying claim:
What I claim is:
A sheave comprising a retaining drum, locking plates mounted on either side thereof forming substantially a U-shaped channel with the drum, the sides of the channel extending angularly with respect to the base and the lateral distance therebetween increasing toward said base, a plurality of tread members radially disposed in juxtaposition on the periphery of said drum and securely mounted" W-ithin' said channel by means 0f the locking plates, each of said tread members being a solid, unitary member of oil-impervious resilient material and shaped to extend the complete lat- 1 eralwlength of said channel, the top end of said member having a plurality of spaced grooves capable ofguiding a correspondin number of sheave cables,:the.sides of each of said members being angularly shaped to conform with the engagingsides of said channel and the circumferential length of said tread member being small relativevtoiits-lateral lengthy whereby -:each ofzthe tread .mem-bersfis rpositioned' on-'-itsibottom iend 'i and i-i'radially with irespect: to :thedrum axisxto'ti' completely cover the?peripherylof-sai'd' drumzi References Gited in the -file--of 1 this patent- UNITED 'STATES :PATENTS Number Name Date. R'f15fl37 Neenan'"; Dec. 25,1923: 387,024 Walker Ju1y31,'.1888" 9565051 Donaldson; Apr.26','191'0 2,605,978 Allard"; Aug. j5, 1952""