US1720840A - Hoist controller - Google Patents

Description

July 16, 1929.' v A E JOHNSON 1,720,840

HoIs'T CONTROLLER Filed DBC. 29, 1927 2 Sheets-SheetA l gnwnto@ July 16, l929- A. E. JOHNSON 1.720.840

HoIsT COTROLLER Filed Deo. ze, 1927 2 sheets-sheet 2 Patented July 16, 1929.

UNITED STATES ALFRED E. JOHN SON, OF DENVER, COLORADO.

HOIST CONTROLLER.

Application filed December 29, 1927. Serial No. 243,458.

This invention relates to improvements in hoist controllers of the type described and claimed in my copending application 226,774, liled October 17, 1927.

It is the object of this invention to produce a simplified form of controller of the type above described.

In mines of different kinds where hoists are employed for the purpose of raising material from a lower to a higher level, and for transporting men from and to the mine, it is necessary to provide the hoist with a vmechanical controller that will make it necessary for the engineer to reduce the speed of the hoist as it approaches the landing place and which will automatically stop the hoist if the speed is eX- cessive at the ends of the travel, or, if the engineer should fail to cut off the power when the cage reaches either the upper or the lower landing.

In controllers of this type it is desirable that the speed at which the hoist may be started from its position of rest shall not operate the controller as to do so would slow down the 5 speed of the hoist without adding anything to the safety and it is therefore one of my objects to provide a hoist controller that shall permit a quick get-away from either the upper or the lower landing. It is apparent that the speed at which the cage is traveling during the intermedi-ate part of its path can be quite high without introducing aniy dangerous condition and that it is the speed at the ends of the cage travel that must be controlled to certain limits in order to provide for a safe landing or stoppage. In the application to which reference has been made, a speed responsive device such as a centrifugal governor' has been provided for the purpose of operating the controller whenever excessive speeds are attained, and in addition to this, cams are provided which automatically change the speed limit as the cage approaches the ends of its travel.

It is the object of this invention to simplify the construction of this type of controller so as to obviate the necessity of a centrifugal governor and also to dispense with the floating lever which is employed in the construction described in the application above identified.

My improved construction can be best described and will be most readily understood if reference is had to the accompanying drawings on which the invention has been illustrated, and in which Fig. 1 is a side elevation of my improved controller, parts thereof being broken away and other parts shown in section, so as to more clearly disclose the invention;

Fig. 2 is a vertical diametrical section of the dashpot, which constitutes the speed responsive device employed in this improved construction Fig. 3 is a view looking into the casing of gie controller in the direction of arrow 3 in 4 is a section taken on line 4 4, Fig. 3; Iiig. 5 is a section taken on line Fig. 3; anc

Fig. 6 is a View similar to that shown in F ig. 3 and illustrates a slightly modified form of construction.

In the drawing numeral 1 represents a base .which is adapted to be secured to a supporting surface 2 and held in place thereon by means of bolts 3 or other suitable means. This base has a central hub 4 to which the lower end of the vertical tubular support 5 is threadedly connected. Secured to the upper end of support 5 is a casing which has been indicated in its entirety by reference numeral 6. This casing has a bottom member 7 two vertical sides 8 and 9 and a curved upper end 10, which joins the upper ends of the sides 8 and 9 in the manner shown in Fig. 3. The bottom 7 is provided with a circular hub portion 11, which has an Opening for the reception of the upper end of tubular member 5. Sides 8 and 9 are provided with bearings 12 in which the shaft 13 is journalled. This shaft is held against longitudinal movement by means of collars 14, or other equivalent means. Secured to one end of shaft 13, is a sprocket wheel 15, which is connected to some movable portion of the hoist mechanism by means of a sprocket chain which has not been shown. The end 16 of the casing is provided with a cylindrical hub portion 17 that has a cylindrical opening for the reception of the shaft 1S. A worm gear 19 is secured to shaft 18 so as to rotate about the axis of this shaft. A worm 20 is secured to shaft 13 and cooperates with worm gear 19 so as to rotate the latter whenever the shaft is rotated. The gear ratios between the hoist mechanism and the worm gear 19 are selected in such a way that worm wheel 19 will make somewhat less than a complete revolution as the cage of the hoist travels from its upper to its lower landing. In the example shown in Fig. 3, the full line position of the parts may be sup- CII posed to indicate the uppermost position of the cage, while the dotted line position of the cranlr pin 2l indicates the lowermost position of the cage. This is of importance in the operation of this device and reference will therefore be made to this feature of the construction as the description proceeds.

Connected to the end of shaft 13 opposite from that to which the sprocket wheel. l is connected. is a friction clutch comprising' two stationary disks 22 and 23, one of which is located on either side of a njrooved pullev 24C. rllhis pulley is freely rotatable on the shaft but can be clamped against rotation whenever disk 28 is moved towards dish 22 with sufficient force. This is accomplished b v the following;v mechanism. Disk 22 is held to the shaft by means of nuts 25 and 2G and is prevented from rotatingby means of tl e noncircular section 27 of the shaft which cooperates with a corres] iondin;l v shaped opening in this disk. Dish 23 is slidable to a limited extent and is held against rotation bv means of a spline which is located in the groove A collar 29 is held against longitudinal and also against rotary movement by means of a pin 30. This collar has two diametrically located slots within which the cam ends of the levers 8l are located. These levers arel pivoted at 32, and are provided at their free ends with pulleys or rollers 33. Collar 34 is Slidahly secured to the shaft and is provided with two cylindrical sections 35 of different diameters. When the parts are in the position shown in Fig. 3, the clutch is inoperative, but if the collar 34 is moved towards the left so as to force the cylindrical section of the larger diameter between the rollers, levers 3l will be spread apart so as to clamp the l`arooved pulley 24 between the adjacent surfaces of disks 22 and 23. hein 36 has one end secured to the pulley 2li and the other end secured to one end of line 86 whose other end is pivotally attached to the outer end of lever 3T. Lever 37 is non-rotatably secured to one end of shaft 3S that is mounted for rotation in a bearino' 39 and which has a lever l0 non-4 rotatably secured to its other end. A rod ll is pivoted to the outer end of lever l0 and extends to a brake mechanism indicated as a whole by numeral 4.2. which controls the rotation of drum 48 which in the illustration reoresents the hoistingmechanism. lt is now apparent that if shaft l?) is rotated from the hoist and if dislr 24C is clamped in the manner explained, the chain 36 will be rolled about pulley 2e and will operate to set the brake mechanism so as to produce a force tendingr to stop the hoist.

For the purpose of controlling the operation of the friction clutch, l have provided a mechanism which will now be explained.

lever 44; has its upper end pivotally connected at l5 to a sleeve @t6 that is slidably secured to the bolt el?. This bolt is provided withva shoulder 48 which serves as one abutment for the spring 9. The center portion of lever lll is connected with a groove in the sleeve 34e by means of a bolt 50. It is now apparent that by moving,` lever le inwardly or outwardly about its pivot 45, that the sleeve 34C will be mov-ed in a corresponding direction and therefore if lever la is moved outwardly with sufficient force7 the cylindrical surface 35 which has the larger diameter will be forced between the rollers 33, thereby making the clutch operative. Jlittention is called to the fact that the lower end of lever ist is bent inwardly so as to form an inclined section 5l, in the manner shown in Fig. 3. A lever 52 extends through an opening 53 in the side 9 of the casing. This lever is provided with a hook portion 5st which embraces the inclined end 5l. A roller is pivotally attached to the lever 52 and normally engages the inner surface of the inclined end 5l in the manner shown. lfor the purpose of holding the lever la against the spring Li9 and the roller 55, a bolt 5G has been pivotally attached to lever 44 and is provided with a spring- 57 that is under compression and tends to move this lever towards the side 9 of the casing. rhe other end of the lever 52 abuts the inside of the vertical side member 8 and is therefore held against longitudinal movement. in order to guide the inner end of lever 52, a plate 5S has been secured to side 8 by means-of screws 59 and this plate is provided with a slot GO within which the end of lever 52 can slide. er pin 6l is pivotally attached to the lever 52 and projects into the upper open end of a tubular casing- 62. A spring G3 is located within this casing and has its upper end in contact with the shoulder. 64. A cap is threadedly connected with the lower end of tubular member 63 and is provided with an adjusting screw 65 that projects upwardly and carries a flange G'Zthat serves as an abutment for the lower end of the spring G3. By means of bolt- 66 the tension in spring 63 can be` adjusted so as to secure the best operation. Lever 52 is provided near its inner end with an upwardly extendingl lugl 68 whose upper end 69 is bent at right angles in the manner shown in Fig. 4. Part 69 is provided with a threaded opening for the reception of an adjusting screw 70. Secured to the upper side of bottom 7 is a lug 7l which is provided with a bearing for the reception of a rotatable shaft 't' 2. Secured to the inner end of shaft 7 2 is a cam 73. This cam is located directly beneath the lower end of screw 70 so that the latter may be moved upwardly or permittedI to move downwardly when the cam is rotated. A handle le is secured to the outer end of shaft 72 and serves as a means for rotating the shaft.

lNhen the handle 7% is in the full line position shown in Fig. 3, the inner endof lever 52 is in its lowermost position. By rotating handle 74 from the full line to the dotted line position, the inner end of lever 52 will be raised owing to the fact that the end of screw will be resting on a portion of the cam farther removed from the center of shaft 72. A weight 75 is supported from the inner end of lever 52 by means of a bolt 76 and serves to maintain the lower end of screw 70 against the'cam surface. Attention is called at this point to the fact that the inner end of lever 52 is provided with a pin 77 that is normally out of contact with but which will make contact with the two electrical contact members 78 whenever the handle 74 is rotated to dotted line position. Contact members 78 form a switch which controls a signal lamp 79 located on the top of the controller' and which therefore indicates the position of lever 52. Under normal operations of the controller, lever 52 and handle 74 occupy the position indicated in full lines in Fig. 3. But when the hoist is to be used for handling men, handle 74 is moved to dotted line position, whereby the speed at which the controller will function, is reduced in a mann-er which will hereinafter be more fully described.

The means employed for controlling the position of the lever 52 and for controlling the friction clutchcomprises a hollow cylindrical member 80, which has its lower end closed by means of a plug 81. This plug is provided with spaced downwardly extending ears 82 which are perforated for the reception of the bolt 83, by means of which connection is made to the lever 52. The upper end of cylindrical member 80 is closed by means of a plug 84. Plugs 81 and 84 are provided with circular recesses 85 which serve to receive the ends of the inner cylinder 86. rThis cylinder has an outside diameter somewhat less than the inside diameter of the cylindrical member 80 so as to leave an annular chamber 87, and is also provided with a plurality of spaced openings 88. A piston 89 is slidably mounted within the cylinder 80 and has attached to it a hollow piston rod 90 which extends outwardly through an opening in the center of plug 84. Piston 89 has a central opening 91 which is in axial alignment with the tubular piston rod 90. This piston is also provided with one or more openings 92, whose lower ends are enlarged in the manner indicated at 93 so as to form a recess for the reception of a steel ball 94 that serves as a check valve and is held in place by means of a plate- 95. A gage 96 is attached to cylindrical member 80 and has a glass 97 whose interior is in communication with the annular space 87 so that the level of the oil within this annular space can be determined by inspection. The inner surface of the upper end of piston rod 90 is threaded for the reception of a plug 98. This plug is provided with a knurled head 99 by means of which it can be rotated and with a lock nut 100 by means of which it can be securely held against accident-al rotation. A rod 101 is secured to plug 98 and extends downwardly, terminating in a conical point 102, a portion of which projects into the opening 91.. By rotating plug 98, rod 101 can be moved upwardly or downwardly so as to control the effective area of opening 91. The outer surface of piston rod 90 is threaded near its upper end in the manner indicated. A head 103 is provided with a threaded opening 104 which cooperates with the threaded upper end of piston rod 90 and is held against accidental rotation by means of a lock nut 105. Head 103 has a in which the knurled head 99 is located, and is also provided with an outwardly extending perforated projection 107 through which t-he pivot pin 21 extends.

It will be observed from Fig. 2 that piston 89 can be moved quite freely in an upward direction as any oil or other fluid will pass downwardly through the openings 90 or inwardly through openings 88 in cylinder 86. 1f this piston is moved downwardly, however. balls 94 will prevent oil from flowing up` wardly through the openings 90 and after this piston has passed the lowermost of openings 88, oil can only pass upwardly through the central opening 91. By adjusting the position of the valve member 101, the rate at which oil can flow upwardly through opening 91 can be adjusted to any extent desired.

Let us now assume that the parts are in the position shown in Fig. 3 and that shaft 13 is rotated so as to cause the disk 19 to rotate in clockwise direction. As disk 19 rotates, piston 89 will be moved upwardly within the cylinder 86, until crank pin 21 passes through a plane extending through the center of pivot 83 and the axis of shaft 18. As the disk 19 rotates, pin 21 will now descend and therefore move the piston 89 downwardly. It is apparent that the up and down move-ment of the piston 89 is very slow near the dead center of the parts and that it increases in speed the farther the crank pin 21 moves away from the`dead center, and therefore the rate at which the piston moves is the greatest when the parts are in such position that the axis of the piston rod 90 makes an angle of ninety degrees with a radius passing through the crank pin 21. It will be observed that this relationship of the parts takes place when the crank pin is some distance below the horizontal plane passing through the axis of shaft 18. The parts are so adjusted that this position is reached by the crank pin as the cage approaches within a short distance of the end of its travel and therefore the controller is more sensitive to speed variation at the ends of the cage travel than at any intermediate point. The position of the valve rod 101 rectangular opening 106 with-` llO is so adjusted that the resistance offered to the movement of piston 89 is not sufhcient to overcome the action of spring 63 when the cage approaches the landing place at the proper speed. But, if the engineer fails to reduce the speed near the ends of the cage travel, the resistance offered to the movement of the piston will be suiiicient to move lever 52 downwardly and this will cause the roller to travel downwardly along the inclined end 51 of lever 44 thereby moving the latter outwardly so as to spread the cam levers 31 apart and cause the clutch to become operative, thereby applying the brake in the manner previously described. Rod 41 which connects the brake mechanism 42 to the movable arm 40, can be extended in the manner indicated by reference numeral 108, so as to control a switch 109 that will disconnect the power supply whenever the brake `is applied.

Attention is Called at this point to spring 49, which will yield so that if the speed near the ends of the travel should be very excessive and therefore the force applied to lever 52, very large, the lever 44 will not be bent or broken, as the upper end will move inwardly due to the yielding of spring 49.

ln Fig. 6 I have shown a slightly modified form of construction in which the crank pin 21 has been omitted from dish 19 and in lieu of this pin two cam members 110 have been provided. These cam members are formed on the outer ends of arms 112 that are secured to the shaft 18 and held in place thereon by means of set screws 113. By means of the set screws the arms 112 may be adjusted rotarily about shaft 18. 1n this modilic'ation the inner end of lever 52 is pivoted at 114 to a bracket 115 that extends inwardly from side 8 ofthe casing. Bracket 116 projects inwardly from side 8 and is provided with a pivot 117 to which the lever 118 is pivoted. The other end of this lever is pivoted at 119 to the head 107 that is secured to the tubular piston rod of the dashpot. The lower end closure of the cylinder 8 is pivoted to lever 52 at 83. A downwardly extending'rod 120 is pivoted to lever 118 at 121 and carries a spring 122. r1`he upper end of this spring abuts the lower end of a nut 123 and its lower end abuts the washer 124 that rests on the upper end of the tubular member 125 whose lower end is attached to lever 52 at 128. Spring 122 is under compression and tends to move lever 118 upwardly about its pivot. The strength of this spring is sufficient to move the piston 89 upwardly in the dashpot cylinder unless it is opposed by the action of the cams 110 and 111. A roller 127 is pivoted to lever 118 and is located in the path of the cam surfaces so that it will be engaged by the latter at predetermined positions of the disk 19. Lever 44 has been constructed in a slightly different manner from that shown and described in Fig, 1, the

main difference being that instead of having the inclined end 51, a spring 128 has been provided. rlhis spring has an inclined portion 51 that corresponds to the inclined end 51 in Fig. 3. This spring is secured to the leverby means of .a clamp 129, in such a way th at its position may be moved vertically with respect to the lever. This forms an adjustment that is taken advantage of in adjusting the operation of the controller to suit different installations. On account of the yielding nature of spring 128, spring 49 has not been employed in this construction. nstead of the mechanism comprising cam 73 and handle 74 which is employed in Fig. 3 for the purpose of changing the controller so that it will operate at lower speeds when handling men, another mechanism has been provided in the embodiment shown in Fig. 6. A rotatable sleeve 130 is lsecured to the pin 47 and is provided at one end with a cam surface 131 that cooperates with the pin 132 which is carried by the ripper end of lever 44. A handle 133 is provided for rotating hub 139. Itis evident that the farther the upper end of lever 44 is moved away from side 9 the shorter the outward movement of the lower end of the lever must be in order to operate the friction clutch, and therefore whenever the hoist is used for handling men, the cam 131 is rotated so as to move the upper end of lever 44 outwardly, while normal operation requires the corresponding end of the lever to be as close to the side 9 as this cam will permit.

rEhe sprocket wheel 15is connected with some movable part of the hoist mechanism, such as the shaft that rotates the drum, and the gear ratios are so calculated that disk 19 will rotate more than one hundred eighty and less than three hundred sixty degrees as the cage travels from its lowermost to its uppermost position. rlhe cams 110 and 112 are so adjusted that they will engage the roller 127 when the cage approaches within a short distance of the end of travel, and will move the lever 118 downwardly. The dashpot is so adjusted that if the speed of the hoist is properly controlled by the engineer and gradually reduced as the cage nears the ends of its travel, the friction clutch will not be operated but if the speed is too high for safety the force exerted by the dashpot will move lever 52 downwardly and thereby move the lower end oflever 44 outwardly so as to make the friction clutch operative and thereby stop the hoist.

Attention is called to the fact that in this construction floating levers are not employed as both levers 44 and 52 rotate about fixed pivots during the operation.

l want to call particular attention to the fact that I employ a dashpot for the purpose of obtaining a force that varies with the speed of the hoist. A. dashpot is simpler construction than a centrifugal governor and can be more readily adjusted so as to produce the required force. It will also be observed with the constructions above described there is no speed control during the center of the cage travel and this permits the cages to travel very fast between landings so that the capacity of the hoist will not be reduced by the controller mechanism. lVhere a centrifugal governor is employed, this is liable to function at any part of the cage travel and therefore the engineer must be very careful to keep the speed low during the entire travel of the cage.

Since the force which is used for moving the clutch members into operative position is produced by the action of the dash pot and since the two parts of the dash pot are never positively interconnected, but are connected by means of a fluid that can escape through an opening, there cannot be as sudden application of the brake as would be the case if the force were applied by an nonyielding mechanism.

Although the fluid controlled speed responsive device has been designated by the term dash pot, I desire to have it understood ythat I do not want to be limited to the exact construction shown, as this is merely illustrative of such a fluid controlled device.

Having described the invent-ion what is claimed as new is l. A hoist controller comprising, in combination, a shaft, a normally inoperative clutch secured to one end of the shaft, a rotatable crank, means for rotating the crank when the shaft rotates and means comprising a dashpot for rendering the clutch operative when the rotatable crank has reached a predetermined speed.

2. A hoist controller comprising, in combination, a support provided with bearings, a shaft rotatably mounted in the bearings, a crank disk rotatably secured to the support, means for rotating the cran-k when the shaft rotates, a normally inoperative brake mechanism, and means comprising a fluid controlled speed responsive device for operating the brake mechanism when the crank a predetermined speed.

3. A hoist controller comprising, in combination, a support provided with spaced bearings, a shaft rotatably mounted in said bearings, a crank rotatably secured to the support, means for rotating the crank when the shaft rotates, a normally inoperative clutch connected with one end of the shaft, a fluid controlled speed responsive device comprising a cylinder and a piston, means for securing one of said parts with the crank and means for operatively connecting the other part of the speed resposive device with the clutch.

4. A hoist controller comprising, in combination, a casing having spaced side walls, a bearing in each side wall, a shaft rotatably reaches mounted in said bearings, a crank disk rotatably secured to the casing, said disk having a crank pin, means for rotating the crank disk Whenever the shaft is rotated, a lever located to one side of the disk, means for holding one end of the lever against movement, the other end of the lever being free to move, a clutch secured to the shaft, said clutch comprising a member rotatably secured to the shaft and two opposed members nonrotatably secured to the shaft, a two-part dashpot comprising a cylinder movable, one of said parts being pivoted to the crank pin and the other to the lever and means operated by movement of the lever in one direction for clamping the rotatable part of the clutch to the shaft.

5. A hoist controller comprising a rotatable shaft, a brake mechanism and a speed responsive device for controlling the opera-- t-ion of the brake, said device comprising a fluid controlled mechanism having two relatively movable parts, one of which is connected with and moved by a movable element whose movement is controlled by the rotation of the shaft and the other of which is connected with the brake control mechanism.

6. A hoist controller comprising, in combinationa rotatable shaft, a movable member, means for moving said member at a rate corresponding to the rate at which the shaft rotates, a brake mechanism and afluid controlled speed responsive device for controlling the operation of the brake mechanism, said device comprising two relatively movable parts, one of which is connected with the movable member so as to be moved thereby and the other with the brake mechanism.

7. A hoist controller comprising, in combination, a support, a shaft rotatably supported thereby, al clutch having relatively rotatable parts, one of which is rotated by the shaft, a brake mechanism, means connecting the brake mechanism with the other part of the clutch, a fluid controlled speed responsive device comprising two relatively movable parts, means for moving one of said parts at a rate proportional to the rate at which the shaft rotates and means attached t-o the other part for operating the clutch when the speed of the shaft exceeds a predetermined value.

8. A safety device for hoists comprising, in combination, a shaft adapted to be rotated at a speed proportional to the speed of the hoist, means for applying a brake to the hoist, said means comprising a clutch having one part rotated by the shaft and another part connected with the brake and a fluid controlled speed responsive device having two relatively movable members, one of which is moved at a rate corresponding to the rate at which the shaft rotates and the other of which is operatively connected with a movable part of the clutch.

9. A safety device adapted to apply a and a piston, which are relatively llO brake to a rotating part of a hoist comprising, in combination, a shaft adapted to be rotated by the hoist, a clutch mechanism comprising two relatively rotatable parts, one of which is rotated by the shaft, the other being normally stationary and connected with the brake, a two part fluid controlled speed responsive device having two relatively movable parts, one of which is movedrelative to the other at a speed corresponding to the speed of the shaft and means comprising one part of the speed responsive device for moving the parts of the clutch into operative engagement.

10. In a hoist having a rotatable drinn and a brake for applying a retarding force to the drum, means for applying the brake when the speed of the drum exceeds a predetermined value, said means comprising, in cembination, a shaft rotated at a speed that corresponds to the speed of the drum, a normally inoperative clutch comprising a rotatable part connected with the shaft so as to be rotated thereby and a normally stationary part connected with the brake, a fluid controlled speed responsive device having two relatively movable parts, means for moving one of the parts relative to the other at a speed corresponding to the speed of the shaft, the other part of the speed responsive device` forming a portion of a means for moving the clutch parts into operative position when the speed of rotation of the shaft exceeds a predetermined amount.

11. A safety device for a hoist having a rotatable drum and a cage comprising, in combination, a movable member, means for moving said member at a speed corresponding to the speed of the hoist cage, a brake mechanism adapted to stop the rotation of the drum, a clutch mechanism comprising two relatively movable parts, one of which is connected with the brake mechanism and the other of which is connected with the movable member so as to be moved thereby and means comprising a fluid controlled speed responsive device extending between the movable member and the clutch for moving the later into operative position when. the movable member is moved at a speed in excess of a predetermined limit.

12. A safety device for a hoist having a rotatable drum and a cage comprising, in combination, a movable member, means for mov; ing said member at a speed corresponding to the speed of the hoist cage, a brake mechanism adapted to stop the rotation of the drum, a clutch mechanism comprising two relatively movable parts, one of which is connected with the brake mechanism and the other of which is connected with the movable member so as to be moved thereby, means comprising a fluid controlled speed responsive device extending between the movable member and the clutch for moving the latter into operative position when the movable member is moved at a speed in excess of a predetermined limit and means for moving the clutch members into operative position when the movable member reaches a position corresponding to the end of the cage travel.

13. A controller for use with hoists, comprising, in combination, a fluid controlled speed responsive device adapted to be operatively connected to the hoist so as to be responsive to the speed of the hoist, and means for applying a brake to the hoist when the speed exceeds a predetermined value, said means comprising a movable member, means for moving the member whenever the hoist moves a clutch having two relatively movable parts, means for moving one of said parts whenever the hoist moves and means controlled by the speed responsive device for moving the clutch members into operative engagement when the hoist exceeds a predetermined speed.

14. A controller for use with hoists having a drum and a brake mechanism, comprising, in combination, a fluid controlled speed responsive device having two relatively movable parts interconnected by a fluid, means for connecting one of said parts to the hoist so that it will be moved at a speed corresponding to the speed of the hoist, a clutch comprising two relatively movable parts, means for connecting one of the clutch parts to the other part of the speed responsive device, a brake mechanism operatively associated with the hoist, means for connecting the brake mechanism with the other clutch part and means comprising the speed responsive device for moving the two parts of the clutch into operative position when the speed of the hoist exceeds a predetermined value.

15. A controller for use with hoists having a drum and a brake mechanism, comprising,

vin combination, a fluid controlled speed responsive device having two relatively movable parts interconnected by a fluid, means for connecting one of said parts to the hoist so that it will be moved at a speed corresponding to the speed of the hoist, a clutch comprising two relatively movable parts, means for connecting one of the clutch parts to the other part of the speed responsive device, a brake mechanism operatively associated with the hoist, means for connecting the brake mechanism with the other clutch part, means comprising the speed responsive device for connecting the two parts of the clutch when the speed of the hoist exceeds a predetermined value and means for connecting the two parts of the clutch when the hoist approach-es within a predetermined distance from its limit of travel.

16. A controller for use with hoists having a cage movable between an upper and a lower landing, a drum connected with ythe cage by means of hoisting cables and a brake mechanism for stopping the rotation of the drum comprising, in combination, a shaft mounted for rotation, means for rotating the shaft when the drum is rotated, a clutch mechanism carried by the shaft, said mechanism Comprising a member rotatable on the shaft, another member rigidly secured to the shaft so as to rotate therewith and means slidable longitudinally of the shaft for forcing the rotatable clutch member towards the other clutch members, a floating lever having an intermediate portion pivotally Connected With the slidable clutch member, the upper end of said lever being movably supported, and

means for moving the floating lever so as to make the clutch operative whenever the speed of the hoist exceeds a predetermined value, said means comprising a speed responsive fluid controlled device having two relatively movable parts one of which is connected with means that moves it at a rate corresponding to the speed of the hoist and the other of which is operatively connected With the floating lever.

In testimony whereof I ailix my signature.

ALFRED E. JOHNSON.

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