US2947430A - Hoist cable equalizer assembly - Google Patents

Description

K SCHNE 60 ASSEMBLY 19 HOIST CABLE EQUALIZER 2 sh ets- 1 Filed Aug, 30, 1955 N V EN TOR. Kmez. sfllvslptz B Y 'm m 4/ ATTORNEYS 1960 K. SCHNEIDER 2,947,430

HOIST CABLE EQUALIZER ASSEMBLY Filed Aug. 30, 1955 2 Sheets-Sheet 2 I Zl/I/l/I/ 171/14 FIG. 5.

INVENTOR.

. I A 42 4,7 K43 Salve/0:2

w wrm ATTORNEYS United States Patent M HOIST CABLE EQUALIZER ASSEMBLY Karl Schneider, Milwaukee, Wis., assignor to Harnischfeger Corporation, Milwaukee, Wis., a corporation of Wisconsin Filed Aug. 30, 1955, Ser. No. 531,525

9 Claims. (Cl. 214135) This invention relates to improvements in hoist cable blocks and paritcularly to a hoist cable block which equalizes the tension in multiple lines of cable reeved therethrough.

The hoist cable block of the present invention is particularly adapted for use in a power excavator having a dipper which has a non-linear path of movement. Multiple lines of hoist cable are connected to the block for simultaneous winding on the hoist drum. But for the tension equalizing features of the block of the present invention, the non-linear movement of the dipper would impose unequalized tension on the respective hoist cable lines.

The equalizing block of the present invention is pivotally connected to the dipper bail for oscillation of the block on one axis, the sheave or sheaves about which the hoist lines are reeved having axes of oscillation transverse to the axis on which the block is pivoted to the dipper bail. Accordingly, the pivotal movement of the block on one axis and the oscillation of the sheaves on their transverse axes provides for universal relative movement between the cable lines and the dipper regardless of non-linear dipper movements and the tension in each line will inherently equalize.

The device of the present invention is particularly useful in hoist apparatus utilizing two sets of paired cable lines or parts. For such apparatus I provide a block having dual axially spaced sheaves disposed on axes of oscillation transverse to the axis of oscillation of the block with respect to the dipper. The pivotal mounting of the block to the dipper equalizes tension as between the respective cable pairs and the oscillation of the respective sheaves equalizes tension as between the cable parts or lines in each cable pair.

In this connection, my specific block and sheave structure in which outflanged shoulders on the sheaves bear on complementary shoulders formed on the block housing wall is regarded as novel. This structure eliminates need for sheave axles, the sheaves being retained in the block housing by removable keepers having shoulders complementary to the sheave shoulders. Removal of the keepers facilitates reeving the cable lines about the sheaves as the sheaves are readily bodily removed from the block and the cables manipulated therethrough.

In the drawings:

Fig. 1 is a fragmentary perspective view on a reduced scale showing the block of my invention incorporated in a power excavator.

Fig. 2 is an enlarged perspective view of an equalizer block embodying my invention, ears on which the block is mounted to the dipper bail being shown fragmentarily.

Fig. 3 is a view partly in elevation and partly in section taken through a block embodying the invention and illustrating how a keeper and sheave may be removed to facilitate reeving cable about the sheave. I

Fig. 4 is a fragmentary front elevation of the apparatus shown in Fig. 1, portions of the housing wall being brokenaway to expose internal construction details.

r 2,947,430 Patented Aug. 2, 1960 elevation of an equalizer block of my invention in the extreme upper position of the dipper in which the bumper shoe engages the periphery of the boom pulleys.

Fig. 6 is a plan view of the equalizer block per se, the bumper shoe being removed.

Fig. '7 is a view similar to Fig. 5 showing a modified embodiment of the invention.

As best shown in Fig. 1, the power excavator is conventionally provided with a boom 10 on which a dipper 11 is mounted by means of a dipper stick 12 for its conventional non-linear movements with respect to the boom.

,The boom 10 is provided with ears 13 to which suspension lines indicated collectively by reference character 14 support the boom in tension and are connected to a gantry (not shown) on the frame of the excavator.

The upper end or point of the boom is provided with a cross shaft or axle 15 on which double grooved pulleys or sheaves 20, 21 are mounted. Sheave 20 has grooves 16, 17 and sheave 21 has grooves 18, 19 (see Fig. 4). About the respective sheave grooves 16 through 19 are bent four parts or lines 22, 23, 24 and 25 of cable. The lines are arranged in cable pairs 22, 24 and 23, 25. The respective cable pairs have end loops reeved through cable block 26 which is pivotally mounted on pin 27 to spaced ears 28 on the dipper bail 29.

The respective cable pairs have their otherwise free ends connected to the hoist drum within the excavator cab for simultaneous winding thereon. Accordingly, the cable lines 22 25 function in the manner of a single tension member. Accordingly, it is desirable that the load be divided equally in the respective lines to avoid placing excessive tension on any one line.

Provision for multiple cables which act in the manner of a single cable is particularly desirable where the weight of the dipper and its load is high. The diameter of the boom point sheaves should be at least twenty-four times the cable diameter. Accordingly, to avoid using relatively inflexible large diameter hoist cables, and to keep the diameter of the sheaves 20, 21 reasonably small, the number of lines of cables over which the load is divided is multiplied as aforesaid.

Cable lines 22 and 24 are parts of the same length of cable and have a common loop reeved about hoist block sheave 32. Cable lines 23 and 25 are parts of another length of cable and have a common loop reeved about hoist block sheave 33. The hoist block 26 comprises housing walls having fore and aft cavities or sockets 35, 36 in which the respective sheaves 33, 32 are disposed. The housing wall above the respective cavities is open or slotted to admit the paired lines of cable about their respective sheaves.

The inner surfaces of the housing walls about cavities 35, 36 are provided with inwardly projecting arcuate bearing shoulders 37 which are complementary with outflanged arcuate shoulders 38 formed on the respective sheaves 32, 33. While the respective shoulders 37, 38 may be formed at right angles to the side walls of the block and sheave, I prefer to form the shoulders at slight complementary angles or tapers as shown. Accordingly, the sheaves will be axially self-centering. As best shown in Fig. 5 the axes A-A and BB respectively of sheaves 32, 33 are obliquely related to more closely align the cable parts with the grooves of the boom point sheaves when the dipper is close to the boom point.

The axes of oscillation of the sheaves 32, 33 is transverse to the axis of pin 27 on which the housing may pivot as a whole with respect to the dipper 11. Pivotal movement of the housing on pin 27 equalizes tension as between the respective sets of cable pairs 22, 24 and 23, 25. Oscillation of the respective sheaves 32, 33 on their respective axes of oscillation will equalize the tension as between the respective lines in each cable pair. Accordingly, regardless of the position of the dipper within the range of its movement at the end of the dipperstick 12,

tension-onithe hoist, cables-will be equalized. Shoulders 37' are arcuately-discontinuous below the horizontal-center, line of the block cavities andthe housing wall.- is open beneath the cavities 35, 36 to permit vided with cars 43 having apertures 44 to receive the mounting pins 45-which removably/mount the keepers in assembled position; the ends of the rods 45 engaging suitable apertures 46- provided in the skirt 47 of the hoist block housing.

The sheaves 32, 33 do not have axles in the conventional sense inasmuch as all bearing engagement between the sheaves and the block housing is provided by the interengagement of the sheave shoulders 33 with the housing wall shoulders 37 and keeper shoulders 42. Disassembly of the sheaves 32, 33 from the housing is eflected simply by removing keeper pins 45 and withdrawing the sheaves through the open ends of their respective cavities. x Inasmuch as the pulleys 16-19 are necessarily axially spaced on their common axle shaft 15, and the cable lines 22-25 correspondingly spaced, as best shown in Fig. 4, I desirably laterally space the axes of oscillation of the sheaves 32, 33. As best shown in Fig. 6, the respective axes;A-A- and B-B-of sheaves 32 and 33 are laterally ofiset a distance 56 equal to the axial spacing between pulley grooves 16 and 17. Accordingly, when the dipper islifted-to its extreme uppermost position, the lines 22-25 are substantially aligned with the pulley and sheave grooves, notwithstanding the pulley ofiset aforesaid.

The manner of reeving the respective cables about their hoist sheaves is best illustrated in Fig. 3. Keeper 41 is simply removed from the block, thus permitting the sheave 32to'be; withdrawn from its cavity 36. The looped end of a cable pair is then inserted through the slot 48, completely through and beyond the cavity 36'and engaged inthe grooved periphery of the sheave. The cable pair is then drawn upwardly to restore the sheave to itsposition withinthe cavity 36 and the keeper secured by its pin 45 to close the bottom of the cavity 36.

To preclude abrasion of the cable strands 22-25 on any part of the hoist block assembly, particularly when the block is proximate the boom point sheaves as shown in Fig. 5, the walls of the block housing adjacent the path of movement of the cable lines into sockets 35, 36 are flared outwardly as shown at 49 in Figs. 2 and 4. Accordingly, the cable parts enter the sockets through tapered'or funnel-shaped ports.

To preclude contact shock damage to the block 26 or boom point sheaves 20, 21, I may optionally provide the block embodiment shown in Figs. 1 through 6 with a bumper shoe 52 pivotally mounted on pin 53 to car 51 on the top of the block 26. The shoe has spaced cars 50 embracing block ear 51 and has a concave face 54 which may engage the axially extended contact flanges 57 of the boom point sheaves 29, 21 when the cables are fully wound in. The bumper shoe 52 may be provided with a transversely extending rod 55 having axial extent sufficient to laterally engage the forward cable pair 23, 25 to preclude the bumper shoe from flopping forwardly to a position whereits concave face 54 might not properly engage the sheave flanges 57. The rod 55 has substantial axial extent beyond the cable lines 23, 25 to preclude the lines from slipping around the rod ends when the cable Iinesareslaked.

The modified block shown in Fig. 7 is very similar to the embodiment previously described and the same reference characters are applied to identical parts. The difference between the two embodiments is primarily in the structure of the bumper shoe and its connections to the block housing.

The upstanding bumper shoe connecting ear 60 on the block housing 59 is somewhat vertically elongated and is provided with two vertically spaced laterally extending removable pins6-1, 62. Both of thesepins normally engage apertures in the paired bumper shoe cars 63" which embrace the car 66. When both pins are engaged in their respective ear apertures, the face 64 'of the bumper shoe will be held in relatively fixed relationship with the block housing 59. The incline of shoe face 64 is such that in this fixed position the shoe face will always engage the flanges 57 of the boom point sheaves in substantially full face contact when the cables are fully woundin; Unlike the bumper shoe 52 of the embodiment of the invention Shown in Figs. 1 through 6, the shoe 64 of the device shown in Fig. 7 is not free to oscillate on its mounting.

The top and bottom margins 65 and 66 of the shoe face are flared as shown to insure smooth engagement with the flanges 57 on the boom point sheaves regardless of minor variations in the position of the block .at the time of initial contact.

The shoe face 64 is also provided along its lower margin 66 with a reversely curved abutment flange 67 which normally engages a complementary contactledge 68 formed on the housing at one side of the block. As hereinafter pointed out, removal of pin 62 permits oscillation of the shoe 64 about pin 61 to swing abutment flange 67 away from ledge 68.

The shoe is also provided with a hollow tubular pin 71 which may be integrally cast with the shoe and about the same distance beyond the ears 63 as pin 55 shown in Fig. 4. The tubular pin 71 lies between the respective cable pairs 22, 24 and 23, 25.

There may be a tendency for the hoist cable equalizer block to slide on its shoe 64 around the periphery of the boom point sheaves 20, 21 after the shoe makes initial contact with the sheave flanges 57, if tension on the cables is maintained. This movement tends to cramp the freely oscillatory shoe 52 of the embodiment of the invention shown in Figs. 1 through 6 against sheave 32. Because of its control ledge 68 and abutment flange 67, this cannot happen in the structure of Fig. 7 and for that reason the Fig. 7 embodiment is preferred.

If the equalizer block is slid partly around the periphery of the boom point sheaves, the approximate direction of dipper bail pull may be along line 72. Accordingly, the block 59 tends to oscillate the block toward the sheaves. This condition will load the contact ledges 68 and the equalizer block will be braced'against such oscillatory tendency. At the same time any oscillation as does occur will engage lines 23, 25 of the forward cable pair against the hollow cable retainer pin 71. The tension in lines 23, 25 helps to maintain pressure of the upper part of the bumper shoe 64 against the sheave flanges 67 and opposes the tendency of the block to oscillate.

In its illustrated position bumper shoe 64 blocks reeving access to the sheave socket 36. in order to remove this obstruction pin 62 may be withdrawn and bumper shoe 64 oscillated about pin 61 to give access to opening 48 to socket 36. The looped end of cable pair 22, 24 may then be reeved about sheave 32 as shown in Fig. 3. As soon as the cable is reeved, however, the bumper shoe is restored to its position in which its abutment flange-67 engages contact ledge 68 and pin 62 is replaced.

I claim:

1. In an excavator having hoist drum means, a boom with four substantially coaxial boom point sheaves arranged in axially spaced closely adjacent sheave pairs, and a dipper movable with respect to said boom and boom point sheaves, the combination, of two sets of .cable pairs J mnr. r

having two lines each, the respective lines of each cable pair being bent over respective sheaves of each pair of boom point sheaves and connected to said hoist drum for simultaneous winding thereon, a hoist equalizer block and means mounting said block on the dipper for pivotal movement about one axis, said block having dual sheaves mounted thereon for oscillation on ares transverse to the axis of pivotal movement of the block and transverse to the axis of the boom point sheaves, one cable pair being reeved about one block sheave in non-running relation thereto and the other cable pair being reeved about the other block sheave, the axes of both block sheaves being within the bight of both cable pairs, the oscillation of said block sheaves about their axes equalizing tension as between cable lines in each cable pair and the oscillation of the entire block about its pivotal mounting on the dipper equalizing tension as between the respective cable pairs.

2. The device of claim 1 in which the grooves of the boom point sheaves for each set of cable pairs are axially spaced, the axes of the dual sheaves in the block being correspondingly laterally spaced whereby the respective cable lines will align with their respective boom point sheave grooves and hoist block sheaves in all positions of the dipper.

3. In a hoist block having sleeves and sockets for reception of said hoist block sheaves, said sheaves being provided near their outer peripheries with arcuate hearing shoulders, said hoist block comprising walls about said sockets and having complementary bearing shoulders engaged with the sheave shoulders, said block having end openings to admit the cable pairs about said sheaves, said block shoulders being discontinuous about said sheaves opposite the cable pair admission openings whereby said sheaves may be slid laterally out of said block in the course of reeving the cable pairs about said sheaves.

4. The device of claim 3 in which said hoist block is provided with removable keepers having shoulders complementary to the sheave shoulders and means for removably mounting the keepers to close said block sockets and to center the sheaves therein in a position defined by the shoulders on the hoist block wall and the opposed shoulders on the keepers.

5. In a hoist cable equalizer block assembly comprising a sheave housing having a socket and a sheave removably disposed within said socket, the improvement for rotatably supporting said sheave from near its periphery in said socket and leaving the central portions of the sheave otherwise unsupported and comprising arcuate bearing shoulders near the periphery of said sheave, the housing having walls about said socket provided with complementary bearing arcuate shoulders engaged with the sheave shoulders, said shoulders comprising bearings on which the sheave is oscillatable in said housing, said housing having a slot opening into said socket for reception of a cable reeved about said sheave, said hoist block being provided with a removable keeper having shoulders complementary to the sheave shoulders and means removably mounting the keeper to close the block socket and to center the sheave in said socket in a position defined by the shoulders on the hoist block wall and the opposed shoulders on the keeper.

6. In a device of the character described, a hoist block comprising a housing having a sheave socket, a sheave rotatably mounted therein, and a contact ledge, a bumper shoe having an abutment, and means connecting said shoe to said housing with the abutment engaged with the ledge whereby the abutment is in bracing relation to the ledge.

7. The device of claim 6 in which said connecting means is releasable whereby said shoe may be moved to disengage said abutment from said ledge to provide access to said socket.

8. In an excavator having boom point sheaves, a dipper, a hoist block connected to the dipper and cables bent about the boom point sheaves and reeved through the hoist block, the combination with said hoist block of a bumper shoe mounted on the block for contact with the boom point sheaves when the cables are drawn in, said shoe being inclined with respect to the cables and having an abutment, said block having a contact ledge engaged with said abutment to brace the block, said shoe being further provided at a point spaced from said abutment with means against which said cables may bear to maintain pressure of the shoe against the sheaves.

9. The device of claim 8 in which said means comprises a rod mounted on the shoe and extending laterally therefrom for engagement with said cables.

References Cited in the file of this patent UNITED STATES PATENTS 805,096 Russell Nov. 21, 1905 2,218,412 Ball Oct. 15, 1940 2,300,374 Turner Oct. 27, 1942 2,347,456 Beckwith Apr. 25, 1944 2,498,321 White et a1. Feb. 21, 1950 2,546,683 Young Mar. 27, 1951 2,579,888 Watt Dec. 25, 1951 2,734,718 Minor Feb. 14, 1956 FOREIGN PATENTS 631,978 Germany July 4, 1936

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