US2400358A

US2400358A - Snubber for hoists

Info

Publication number: US2400358A
Application number: US500107A
Authority: US
Inventors: Earl B Lear
Original assignee: Cleveland Pneumatic Tool Co
Current assignee: Cleveland Pneumatic Tool Co
Priority date: 1943-08-26
Filing date: 1943-08-26
Publication date: 1946-05-14
Anticipated expiration: 1963-05-14

Description

May 14, 1945. E. B. 'LEAR' I SNUBBER FOR HOISTS Filed Aug. 26, 194:5

\ 2 Sheets-Sheet 1 v N R o W A INVENTOR EAR; B. LEAR B stantially on line 2--2 of Fig. 1.

Patented May 14, 1946 [SNUBBER roa nois'rs Earl B.'Lear,.Gariield Heights, Ohio, asslgnor to The Cleveland, Pneumatic Tool Company, Cleveland, Ohio, a corporation'of Ohio Application August 20, 1943, Serial No. 500,107

9Cla'ims. (c1. ts-7'7) The present invention relates broadly to winding apparatusor hoists and} more particularly, to an improved snubber'mechanism' for the same.

The primary object of the invention resides in the provision of novel snubbing means for a winding reel or the like which will-prevent backlash and tangling of thecable being wound thereon.

A further object of the invention is to provide a snubbing mechanism which may form a part of the friction member or brake of the winding reel or may be attached thereto in a manner to prevent backlash and tangling of the cable being wound on said 'reel.

tion snubber or" brake, which is normally orcontinuously'applied for preventing backlash, is autothe gear casing I8. A tie rod It extends longitudinally through the upper end of the bearing supports l3, ,and I5, whileother tie rods and 2| extend on opposed sides of .the hoist a through ears extending laterally of said bearing brake drums rotate with their respective winding a reels. Eachpof the brakedrums has. associated matically released upon actuation of the clutch from a more complete examination of this speciilcation. 1 a

. In the drawings which illustrate the invention: Fig. 1 is a side elevational view of winding apparatus embodying the invention.

Fig. 2 is a transverse sectional view taken sub- Fig. 3 is a partial side elevation illustrating the snubber and releasingmember.

Fig. 4'is a partial side elevationof the apparatusshowninFigJ. v H

Fig. 5 is a transverse sectional view similar to Fig. 2 but illustrating a modified form of friction device. a v Fig.6 is ade tailed sectional view of the'tension means for supporting one end of the'frlction band. Referring to the drawings for a more detailed description thereof, there is shown a hoist generally designated by the reference numeral ehaving the improved snubbing means embodied therein.

The hoist comprises, in general, a frame shaving thereon a driving motor In and a pair of rotatable winding reels II and l2. The frame 9 in-' therewith a friction device 24 which encircles, or partially encircles, such brake drums.

The friction'device-.24, i i'll,this instance, comprises a brake band 25 havingfriction lining-26 for cooperation wlththe surfacefof the brake drum. It is to be understood that the

brake drums

22 and 23 are each providedwith a friction devicefof the character described, but for purposes-of illustration, only one suchdevice has been shown in the drawings at Fig. 2. .One end ofthe brake band25 is anchored to the frame Sas bymeans of the eye bolt 21. which is surrounded by a'compression spring 28 hearing at one end against the eye of I the bolt 21 and at its other end against the frame 9. The other .end of the brake band' 25fhas a loop terminal-.25 connected'to an ear 30 forming a part of the frame 9. The eye bolt 21 is associated with a brake operating mechanism generally designatedby the reference numeral 3| which comprises a .plate 32 bolted to the frame 9 which carries an operating lever 33, one end of which is in engagement with the teeth of a rack 34. The lever. 33 acts as a pedal to be depressed by the foot of the operator of the hoist for pulling the end of the:brake band secured to the eye bolt into firm engagement with the surface of the brake drum against the tension'of spring 28 to lock'thedrum against rotation," and said brake band is thereby operated independently of the snubber mechanism to be hereinafter more fully described.=

end of the band 35 has riveted or otherwise secured thereto an L -shaped plate 36 through which extends an eye bolt 3'! carried by and projecting vertically from the tie rod 20: The upper portion ofthe eye bolt 31 carries a compression spring 38 which is disposed between the nut 39 and the p1ate-36 and acts-on the eye bolt so as to continuouslyexert a pull on the band 35, tending to apply the snubber to the brake drum 22 through the friction band 25'. The other end of the band 35 OFFICE carries a looped terminal 48 adapted to receive one end M of a U-shaped connector 42. The terminal 48 is secured to the end M by meanspf a cotter key or the like 43. As shown in Fig. 2 of the drawings, the U-shaped clamp 42 is bowed so as to extend around the outer periphery of the tie rod 2|, and its opposite end 44 is disposed in an opening formed in a lever 45 by means of which the band 35 is held and released from operative engagement with the band 25. One end of the lever 45 is formed as shown at 45' to fit around the tie rod 28 and with the U-shaped clamp 42 is so designed that when said lever is in the locked position shown in full lines in Fig. 2, it is just past the center axis of the tie rod 2|. Slight pressure only is required to swing the lever back beyond center to carry it to the 'dotted line position illustrated in Fig. 2 at which the lever 45 will pull the band against the tension of the spring 38 to firmly lock band 35 in engagement with the brake band 25. The lever 45 is moved to the dotted line position when occasion demands manual unwinding of the cable from the drum. As is understood, raising the lever 45 will release the snubber band 35 and friction band from braking contact with the drum, thus permitting the cable to be freely unwound.

The hoist 8 is provided adjacent each of the

brake drums

22 and 23 with a

clutch drum

46 and 41, respectively, these clutch drums being rotat able on the shaft I6. Extending laterally of each clutch drum is a plate 48 whichis disposed beneath the L-shaped plate 36, as more particularly shown in Fig. 4 of the drawings. As will hereinafter appear, the plate 48 acts, upon actuation of the clutch mechanism, to release the snubber so that the cable can be freely wound on the cable reels II and I2. A friction device 49 is associated with each of the clutch drums and encircles, or partially encircles, the same. The plate 48 is carried by and extends laterally of said device 49. Each clutch drum carries one or more spindles 50 on which the planet gears 5|, usually employed in hoists of this kind, are rotatably mounted. As shown in Fig. 2, each of the brake drums has an internal gear or ring gear 52 therein which is connected with a drive pinion 53 of the shaft I6 by means of the planet gears 5|. When the winding reel I2 is to be rotated, the clutch drum 41 is retarded or held stationary by the friction device 49, and this prevents the idler gears 5i from revolving about the pinion 53 and causes them to rotate on their spindles 58 to transmit torque from the pinion to the ring gear 52. The resulting rotation of the ring gear 52 causes rotation of the brake drum 23 and the winding reel I2 connected thereto. When the winding reel I2 is to :e slowed or stopped, the clutch drum 41 is released and permitted to rotate, at which time the gears 5I travel idly around the shaft I6.

The friction devices 49 associated with the

respective clutch drums

46 and 41, each comprises a band or the like 58 having suitable friction lining or shoes for cooperation with the drum surfaces and having ends 54 and 55 adapted to be drawn together by the lever 56 and link 51 when. the friction device 49 is to be applied to the clutch drum 41. The friction device 49 is disposed around the clutch drum 41 so as to be capable of limited circumferential shifting with the clutch drum when the friction device is applied or tightened against the surface of the drum. This limited shifting of the friction device is utilized in loosening the snubber band 35 through the plate 48, that is by pressure exerted against L-shaped plate 36 to compress spring 38.

The snubber bands 35 are normally applied or .held in engagement with their respective brake bands 25 when the lever 45 is in the full line position shown in Fig. 2 so as to hold the winding reels against unintentional or excessive rotation which would cause backlash or tangling of the cable. When one of the winding reels II or I2 is to be rotated, its respective clutch lever 56 is actuated to apply the friction device 49 to the

clutch drum

46 or 41 to retard or stop said clutch drum. As explained above, this results in the winding reel being driven from the shaft I6 through the gears 5|, 52, and 53. When the friction device 49 is tightened against its clutch drum, it is immediately carried or shifted circumferentially by the clutch drum, and such movement is transmitted by the plate 48 to the spring held end of the snubber band 35 in a direction to compress the spring 38 and release the snubber from its engagement with the brake band 25. The release of the snubber 35 permits the winding reel I2 to be freely driven for the desired winding operation. When the winding reel I2 is to be stopped, the clutch lever 56 is swung in the opposite direction to release the friction device 49, whereupon, the spring 38 immediately applies or tightens the snubber band 35 against the brake band 25, and the action of the brake band against the brakedrum 23 will prevent over-running of the windin reel which would cause backlash and tangling of the cable. In addition to applying the snubber 35 against the brake band 25, the spring 38 also acts throughithe plate 48 to return the friction device 49 of the clutch means to its initial position.

In Fig. 5 of the drawings, it will be observed that the brake band 25 and its brake actuating means have been dispensed with, and the snubber band I35 is provided with a friction lining I36 which is in direct engagement with the surface of the brake drum I23. One end of the snubber band carries a plate I36 through which extends an eye belt I31 carried by the tie rod I28. The compression spring I38 is supported between the plate I36 and a bolt I39. The other end of the snubber band I35 is connected'with an actuating lever I45 through the U-shaped clamp MI in the manner previously described in connection with the illustration of Fig. 2. Upon operation of the clutch friction device through the lever 56, the snubber band 35 acts directly against the surface of the brake drum I23 to prevent over-running of the winding reel and thus preclude possibility of tangling'of the cable. This form of the invention is to be employed with those devices which do not use a brake operating mechanism of the type shown in Fig. 2.

It will be seen from the foregoing description and the accompanying drawings that there has been provided an improved winding apparatus or hoist in which a snubber for the winding reel is automatically released upon actuation of the clutch controlling the winding operation and is automatically reapplied upon realease of the clutch. It will be seen also that this automatic snubbing'action is obtained through the use of simplified apparatus utilizing the circumferential shifting of the friction device of th clutch means for actuating the snubber.

Although the foregoing description is necessarlly of a detailed character, in order to completely set forth the invention, it is to be understood that the specific terminology is not intended to be restrictive or. confining and, it is to be further understood that various rearrangements of parts and modifications of structural detail may I be resorted to without departing from the scope or spirit of the invention as herein claimed.

I claim: 1. In apparatus of the character described, a base frame, longitudinally spaced bearing supports extending vertically from said frame, a tie rod on each side of said bearing supports and v g with one of said drums arjc adapted to be applied thereto to'retard rotation of said one drum, a.

friction device associated with the second drum to retard rotation thereof, a member carried by and extending vertically of one of said tie rods, an

L -sh'aped plate secured to one end of said second drum friction device and slidablylheld on said member, a tension spring on said vertically exextending longitudinally therethrough, a pair of said second friction device to the other of said tie rods, and means interconnecting said friction devices so that the release of said one friction device automatically causes the application of the other friction device to its drum.

2. In apparatus'of the character described, a

base frame, longitudinally spaced bearing supports extending vertically from, said frame, a tie rod on each side of said bearing supports and extending longitudinally therethrough, a pair of adjacent drums rotatably carried by said frame within said supports, a friction device associated with one of said drumsand adapted to be applied thereto to retard rotation of said one drum, a friction device associated with the second drum to retard rotation thereof, a member carried by and extending vertically of one of said tie rods, means projecting from one end of said second drum friction device and slidably held on said member, means for placing said projecting means under tension, means for releasably attaching. the other end of'said second friction device to the other of said tie rods, and means interconnecting said friction devices so that the release of said one friction device automatically causes the ap-.

piication of the other friction device to its drum.

ports extending vertically from said frame, a tie rod oneach side of said bearing supports and extending longitudinall therethrough, a pair of adjacent'drums rotatably carried by said frame within said supports, a friction device associated tending member for exerting pressure on said L- shaped plate, a clamp carried by the other end of said second drum friction device and associated with the other of said tie rods, a lever carried by said clamp for manually releasing said second drum friction device from its drum, and means interconnecting said friction devices so that the release of said one friction device automatically causes the application of the other friction device to the drum independently of said lever.

5. In apparatus of the character described, a base frame, longitudinally spaced bearing supports extending vertically from said frame, a tie rod on each side of said bearing supports and extending longitudinally therethrough, a pair of adjacent drums rotatably carried by said frame within said supports, a friction device associated with one of said drums and adapted to be applied thereto to retard rotation of said one drum, a friction device associated with the second drum to retard rotation thereof, a member carried by and extending vertically of one of said tie rods, an L-shaped plate secured to one end of said second drum friction device and slidably held on said member, a tension spring on said vertically extending member for exerting pressure on said L- shaped plate, a clamp connected to the other end of said second friction device, said clamp being substantially U-shaped and bowed intermediate its ends to surround the other of said tie rods, a lever carried by said clamp for manually releasing said second drum friction device from its drum, and means interconnecting said friction devices so that the release 'of said one friction device automatically causes th'e application of the other friction device to the drum independently of said lever.

6. In apparatus of the character described, a frame comprising end members, two parallel tie rods one on each side of said frame connecting said end members, a shaft journaled in said end members, a brake drum rotatably mounted on said shaft between said tie rods, a snubber band extending over said drum between said tierods,

a "manually operable means for releasably connectwith one of said drum and adapted to be applied thereto to retard rotation of said one drum, a friction device associated with the second drum and adapted to be manually operated to'retard rotation thereof, a band disposed concentric to said second friction device and having pressure contact therewith, means for attaching said band to said first named tie rods, and means intercom necting said friction devices so thatthe release of one friction device automaticall causes the application of said band to the other friction device and its drum.

ing one end of said band to'one of said tie rods, and means connected with the other tie rod for anchoring the opposite end of said band.

7. In apparatus of the character described, a frame,'two parallel tie rods one on each side of said frame, a brake drum rotatably mounted between said tie rods, 8, snubber band extending over said drum between said tie rods, means for attaching one end ofthe band to one of said tie rods, resilient means connected with the other tie rod for exerting a pull on the opposite end of the band, and means on said last named end adapted to be moved in opposition to said resilient ply braking pressure to said drum or to permit free rotation of the drum, a snubber band mount ed exteriorly of said brake band, and means for contracting or expanding said snubber band to cause said brake band to trict-ionally engage or release said drum.

9. In apparatus of the character described, a rotatably mounted brake drum, a brake band substantially surrounding said drum, means for contracting or expanding said brake band to apply braking pressure to said drum or to permit free rotation oi the drum, a snubber band mounted exteriorly of said brake band, means for automatically contracting said snubber band, means responsive to drum rotation in one dime-- tion for expanding said snubber band, and manual means for disabling said snubber band.

EARL B." LEAR.