US2973941A

US2973941A - Self-braking winch

Info

Publication number: US2973941A
Application number: US757014A
Authority: US
Inventors: Thomas T Lunde
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-08-25
Filing date: 1958-08-25
Publication date: 1961-03-07
Anticipated expiration: 1978-03-07

Description

March 7, 1961 -r. 1-. LUNDE SELF-BRAKING WINCH 2 Sheets-Sheet 1 Filed Aug. 25, 1958 IN V EN TOR. 77/0/1445 7." L [mp5 A Tram/gr 2 Sheets-Sheet 2 Filed Aug. 25, 1958 INVEN TOR.

THOMAS 77 L UNDE ATTORNEY United States Patent SELF-BRAKING WINCH Thomas T. Lunde, 233 Cervantes Blvd., San Francisco, Calif.

Filed Aug. 25, 1958, Ser. No. 757,014

Claims. (Cl. 254-186) This invention relates generally to self-braking winches, and more particularly to a winch having a rope drum designed to brake itself after the rope or cable carried thereon has been fully played out or'discharged.

Modern hand or power winches generally are provided with braking means associated with the drum upon which the hoisting rope or cable is wrapped. Such braking means may serve to control the speed of rope drum rotation, todecelerate the rope drum to a complete stop after the rope or cable carried thereon has been discharged, or to prevent rotation of the rope drum and hold it in a particular position. Various types of friction or magnetic brakes are most generally used for this purpose and these devices are relatively expensive and complicated.

The present invention contemplates a winch having a simple inexpensive braking means, which may be generally applied to most winches, whereby the momentum of the rotating rope drum itself is utilized to decelerate and stop the drum after the full length of rope carried thereon has been played out or discharged.

The principal object of this invention, therefore, is to provide a winch having a simple and inexpensive means for smoothly decelerating and halting the rotation of its rope drum at such time as the rope wound thereon has been fully played out or discharged.

A further object of this invention is to provide a rope drum braking means which does not impose excessive bending forces upon the rope as the rotation of the rope drum is halted.

Another object of this invention is to provide a rope drum braking means that is self contained and generally applicable to various types of winches.

The foregoing and numerous other objects and advantages of this invention will be more apparent from the following detailed description when considered in connection with the accompanying drawings and the appended claims. a

'In the drawings:

Fig. l is an end elevational view of a winch embodying features of the present invention;

Fig. 2 is a side elevational view of the winch; and

Fig. 3 is a sectional view through the winch rope drum taken along line 3-3 of Fig. 2.

Referring to the drawings more in detail wherein like numerals have been employed to designate similar parts throughout the various figures, a typical hand winch is illustrated and referred to generally as 1. It will be observed in Figs. 1 and 2 that the winch is provided with a hand wheel 2 which is geared through

spur gears

3 and 4 to the rope drum 5. The hand wheel shaft 6 is provided with a ratchet 7 and pawl 8 to prevent reverse rotation of the rope drum under load. These are wellknown features of the prior art winch designs.

The winch described herein is provided with a release lever 9 pivoted from the winch frame 10 on a shaft 11. On this same shaft 11 is mounted a single tooth pinion ice 12, the single tooth of which engages the ratchet 7. The release lever 9 at about its middle is connected by means of a spring 13 to the pawl 8. It will be observed in Fig. 1 that by moving the release lever 9 in a clockwise direction, the single tooth pinion 12 rotates the ratchet 7 in a counterclockwise direction while at the same time the spring 13 urges the pawl 8 to disengage from the ratchet 7. In this manner the ratchet 7 and pawl 8 may be completely disengaged by moving the release lever, and when the release lever has moved sutfioiently in a clockwise direction, the tooth of the single tooth pinion 12 disengages from the ratchet 7. The rope drum 5 then is unrestrained and free to rotate so long as the release lever 9 and the spring 13 maintain the ratchet 7 and pawl 8 is disengagement. v

The present invention contemplates a winch which wil rotate freely to discharge the rope carried thereon and which through its own momentum will decelerate and. stop the rope drum rotation after the full length of rope has been discharged. For this purpose a sheave arrangement is provided on the winch rope drum to cause the rope or cable to spool back upon the drum as hereinafter described.

It will be observed in Fig; 3, that the rope drum 5 has been divided into two similar halves by a center plate 1'5 welded to the center of the drum spool 16 so that separate 8 cables or ropes 14a and 14b may be wound simultaneously on each half of the spool 16. Each rope 14a and 1412, respectively, is atfixed to the center plate 15 by means of a plurality of clips 17 such as the Crosby clips I illustrated herein. The end of each cable or rope is centered on a half-sheave 18 also welded to the center plate 15 and the ends are held firmly in such position ,by the clips 17. The half-sheaves 18 are mounted diametrically opposite each other on opposite sides of the center' 7 plate 15 with their respective centers located on the same center line of the drum substantially as shown in Fig. 3.

The half-sheaves 18 are fabricated by cutting in half an ordinary steel sheave familiar to those skilled in this art. At such time as the ropes carried on the spool 16 U have been fully discharged or played out and the spool momentum causes the spool to continue rotating, these half-sheaves 18 function to redirect the ropes 180 with respect to the direction of rotation of the drum 5 so that the ropes wrap around the half-sheaves 18 and start spooling back on the drum spool 16 in the direction opposite that in which they previously had been wound on the spool. The redirection of the ropes is illustrated vfor.

rope 14a in dotted lines on Fig. 3.

It willbe seenthat when the rope begins to spool back 7 ion the spool 16 aforce in opposition to the angular momentum of the rotating drum 5 is developed by the weight of the discharged ropes alone or by the weight of the ropes and their connected loads which decelerate the drum smoothly to a complete stop. Moreover, the ropes or cables are not damaged in the reversal since rather than bending sharply in a small radius, they are guided by the half-sheaves 18 through a bend having the radius of the half-sheaves, in the selected embodiment several times the radius of the rope.

This concept is particularly adapted for operating dump-gates of a bottom-dump barge, more fully described in co-pending application No. 756,198, now Patent No. 2,927,550, wherein the dump-gates by reason of their own weight and the weight of lading upon them are designed to fall free to the open position, simultaneously unwinding cables interconnected between the dump-gates and a winch adapted for subsequently raising the dump-gates. In such an installation as the dump-gates reach the fully open position the rope on the winch drum is played out and the momentum of the drum causes the drum to continue rotating. The drum over-travels and proceeds to rewind the rope directed by the half-sheaves 18 in the opposite direction on the drum spool 16. The weight of the gates imposes a braking torque on the drum thus snubbing it to a smooth halt with absolutely no shock'to the drum or its associated gearing. This invention has functioned well even during tests conducted in dry dock where the dump-gates attain maximum possible momentum at the end of their opening motion since in such tests the normal cushioning water resistance is not present.

While specific structural features have been disclosed herein, it should be understood that this invention is capable of modification and changes that may be apparent to those skilled in this art without departing from the scope of the invention. By way of example, the invention need not be used with two ropes as disclosed herein, but has equal utility with only one rope or with more than two ropes. It will also be obvious that the guide sheaves may be made integrally with the drum, rather than being separate elements secured to the drum. Further, the guide sheave 18 need not he used to guide the rope upon rewinding to the same portion of the spool as that from which it has been unwound. Neither is' it necessary that the winding faces of the spool be cylindrical as shown, for other forms of developed surfaces are useful for certain purposes. It will further be apparent that the load need not be a hanging load, but that this device is equally useful for horizontal and angular loads. Other and different alternatives will further suggest themselves to persons skilled in the art upon an understanding of this specification. Therefore, this invention is not to be limited by this description but is defined by the appended claims.

I claim:

1. A self-braking winch comprising in combination a rigid frame; a rope drum including a rope spooling surface rotatably mounted on said frame; a length of rope carried on said drum and having one end afiixed thereto; means for rotating said drum so as to wind said rope thereon; means for disengaging said rotating means and for releasing said drum to rotate in response to an external load connected to said rope; and means for directing said rope to rewind on said drum immediately after said rope has unwound therefrom, said means overlying said rope spooling surface and directing said rope to rewind in a direction opposite that in which it had previously been wound, thereby decelerating the rotation of said drum.

2.. A self-braking winch comprising in combination a rigid frame; a rope drum including a rope spooling surface rotatably mounted on said frame; a length of rope carried on said drum and having one end affixed thereto; means for rotating said drum so as to wind said rope thereon; means for disengaging said rotating means and for releasing said drum to rotate in response to an external load connected to said rope; and guide means mounted on said drum and. spaced radially outwardly from and overlying said rope spooling surface; said guide means engaging said rope after said rope has been unwound from said rope spooling surface, and directing said rope immediately to rewind on said rope spooling surface in a direction opposite that in which it had previously been wound, thereby decelerating the rotation of said drum.

3. A self-braking winch comprising in combination a rigid frame; a rope drum including a rope spooling surface rotatably mounted on said frame; a length of rope carried on said drum and having one end affixed thereto; means for rotating said drum so as to wind said rope thereon; means for disengaging said rotating means and for releasing said rope drum to rotate in response to an external load connected to said rope; and an arcuate member mounted on said drum and spaced radially outwardly from and overlying said rope spooling surface, said arcuate member engaging said rope after said rope has been unwound from said rope spooling surface, and directing said rope immediately to rewind on said rope spooling surface in a direction opposite that in which it had previously been wound, thereby decelerating the rotation of said drum.

4. In a winch having a rotatable rope drum including a rope spooling surface carrying a rope wound thereon with one end afiixed to the drum and having said drum designed to rotate without restraint and unwind said rope in response to an external load connected to said rope, means for decelerating the rotation of the said rope drum after said rope has unwound therefrom comprising an arcuate member mounted on said drum and spaced radially outwardly from and overlying said rope spooling surface, said member engaging said rope after said rope has unwound from said rope spooling surface and directing said rope immediately to rewind on said rope spooling surface in a direction opposite that in which it had previously been wound.

5. A self-braking rope drum for a winch comprising in combination a rope-carrying spool, a rope wound thereon with one end aflixed thereto, a flange extending outwardly from the axis of said spool and perpendicular thereto, and a guide member mounted on said flange, spaced outwardly from said axis of rotation overlying said spool and aligned to engage said rope after said rope has been unwound from said spool so as to direct said rope immediately to rewind on said spool in the reverse direcltion with respect to the angular velocity of said spoo References Cited in the file of this patent UNITED STATES PATENTS