US3690409A

US3690409A - Level winding winch mechanism and heavy-duty drive therefor

Info

Publication number: US3690409A
Application number: US769326A
Authority: US
Inventors: Albert Brauss
Original assignee: SPIDER STAGING Inc
Current assignee: SPIDER STAGING Inc
Priority date: 1968-10-21
Filing date: 1968-10-21
Publication date: 1972-09-12
Anticipated expiration: 1989-09-12
Also published as: GB1249405A; JPS5231097B1

Abstract

A level winding winch mechanism for a suspending staging that includes a frame having an upper portion and a lower portion with a fairlead fixed on the upper portion and a rotatable winch pivotally mounted on the lower portion. The pivot for the winch is below the winch drum axis of rotation. As the wire rope passing through the fairlead approaches an end of the winch drum, that end of the winch drum will be pivoted toward an imaginary vertical perpendicular line between the fairlead and the winch drum. Thus the angle between the wire rope, as it approaches an end of the drum, and the imaginary perpendicular line is kept to a minimum, the effect of which is to maintain the ''''fleet angle'''' at approximately 90* . Also the pivot is remotely spaced from the winch drum axis of rotation to reduce the angle through which the winch drum must pivot and thus allow the use of winch drums of long lengths which would otherwise strike the frame of the staging when pivoted. A pivot control using a primary spring and a secondary spring energized only after the wire rope reaches a predetermined point on the winch drum is provided to counteract the increase in leverage when an extra long winch drum is used. A low temperature-high capacity drive arrangement for a winch on a suspended staging. A pair of worms are driven through spur gears from a common pinion spur gear on a motor shaft. The worms engage two worm gears fixed on a common shaft. A beveled pinion gear is also fixed to an end of the worm gear. The beveled pinion gear meshes with a beveled ring gear which is secured to the winch drum. The distribution of the loading between the worms reduces the operating temperature of the drive arrangement for compliance with the rigid safety requirements for suspended staging. Oil from the worms is splashed against a vertical fin extending down from the top of the worm gear casing. The fin guides the oil into a trough through the walls between the spur and worm gear casing for lubricating the driven spur gears.

Description

United States Patent Brauss Sept. 12, 1972 1 LEVEL WINDING WINCH MECHANISM AND HEAVY-DUTY DRIVE THEREFOR [72] Inventor: Albert Brauss, Redmond, Wash.

[73] Assignee: Spider Staging, Inc., Seattle, Wash.

221 Filed: Oct-21, 1968 211 Appl. No.: 769,326

[52] US. Cl. ..l82/142, 187/27, 254/186, 267/60 [51] Int. Cl ..E04g l/l8 [58] Field of Search...l87/20, 27; 182/142; 242/158; 262/60, 168; 254/187, 186

[56] References Cited UNITED STATES PATENTS 2,998,094 8/1961 Fisher ..182/l42 3,297,312 l/l967 Hines ..267/60 Primary Examiner-Harvey C. I-lornsby Attorney-Graybeal, Cole & Barnard 57 ABSTRACT through the fairlead approaches an end of the winch drum, that end of the winch drum will be pivoted toward an imaginary vertical perpendicular line between the fairlead and the winch drum. Thus the angle between the wire rope, as it approaches an end of the drum, and the imaginary perpendicular line is kept to a minimum, the effect of which is to maintain the fleet angle at approximately 90. Also the pivot is remotely spaced from the winch drum axis of rotation to reduce the angle through which the winch drum must pivot and thus allow the use of winch drums of long lengths which would otherwise strike the frame of the staging when pivoted.

A pivot control using a primary spring and a secondary spring energized only after the wire rope reaches a predetermined point on the winch drum is provided to counteract the increase in leverage when an extra long winch drum is used.

A low temperature-high capacity drive arrangement for a winch on a suspended staging. A pair of worms are driven through spur gears from a common pinion spur gear on a motor shaft. The worms engage two worm gears fixed on a common shaft. A beveled pinion gear is also fixed to an end of the worm gear. The beveled pinion gear meshes with a beveled ring gear which is secured to the winch drum. The distribution of the loading between the worms reduces the operating temperature of the drive arrangement for compliance with the rigid safety requirements for suspended staging. Oil from the worms is splashed against a vertical fin extending down from the top of the worm gear casing. The fin guides the oil into a trough through the walls between the spur and worm gear casing for lubricating the driven spur gears.

7 Claims, 7 Drawing Figures PATENTEDsEP 12 me SHEET .3 [1F 3 WMQWAL LEVEL WINDING WINCH MECHANISM AND HEAVY-DUTY DRIVE THEREFOR BACKGROUND OF THE INVENTION 1. Field of the Invention This invention pertains to winch mechanisms and more particularly relates to an improved level winding winch mechanism for exceptionally long winch drums on a suspended staging and to a drive unit for rotating the winch drum.

2. Description of the Prior Art Heretofore one type of winch mechanism for suspended staging has employed a pivot point which is located above the axis of rotation of the winch drum and about which the winch may pivot. This arrangement has performed satisfactorily for nominal sized winch drums, that is, drums not exceeding about 16 inches in length and having a capacity of approximately 1,000 feet of /16 inch diameter wire rope, for example. Such a pivot arrangement is disclosed in the U.S. Pat. to Fisher No. 2,998,094, issued Aug. 29, I961.

With the increasingly higher elevations of modern buildings, for which the suspended staging is used, it is necessary to increase the wire rope carrying capacity of the winch drums. The capacity is increased in part by lengthening the drum to about 21 inches. Increasing the capacity of the'winch drum by increasing its length presents two serious problems: (1) The angle with which the wire rope meets the surface of the drum (fleet angle) as the wire rope approaches an end of the drum becomes smaller, that is, varies from the optimum approach angle of 90, and as a result increases the possibility of non-uniform winding of the wire rope on the drum. (2) When using an extra long winch drum the wire rope acts through a longer lever arm and exaggerates floppingf of the drum about its pivot. In addition, high modern buildings call for increased running time and heavier suspended platforms and make desirable transmissions of greater load capacity at increased speed. I

The angle of approach of the wire rope with respect to the surface of the drum is commonly called the fleet angle". As is explained in more detail in the aforesaid Fisher patent, the'fleet angle is optimumally 90 to the drum surface as, for example, in the condition when the wire rope is directly beneath the fairlead of the staging frame.

SUMMARY OF THE INVENTION This invention is directed to overcoming the aforementioned problems encountered with increased capacity and length of the winch drum. As to the first problem, the fleet angle is kept close to 90, by shifting the ends of the drum axially while the cable is being wound or unwound. Preferably shifting is obtained by pivoting the winch about a pivot point located below the axis of rotation of the winch drum. Then, with reference to an imaginary vertical perpendicular line through the fairlead which corresponds to a fleet angle of 90, the end of the drum which the wire rope is approaching is pivoted or shifted toward said imaginary perpendicular line to decrease the angle between the wire rope and the imaginary perpendicular line and thus to increase the fleet angle of the wire rope and the surface of the drum. The problem is additionally compensated for by placing the pivot point at a more remote distance from the drum axis of rotation.

To alleviate the second problem, a pivot control mechanism is provided to apply a variable resistance in opposition to the pivotal action of the winch to counteract the increase in lever arm as the wire rope approaches the end of an extra long drum. A primary resistance is continually increased until the wire rope reaches a predetermined point along the length of the drum, for example, three-fourths of the distance across the length of the drum, and then a constantly increasing secondary resistance is added to the primary resistance to counteract the increased leverage. The pivot control prevents flopping of the drum about the pivot as the wire rope is wound or unwound from the drum.

The problem of increased load is overcome by using a double worm drive with each worm sharing in the load distribution. In addition, a unique oil distribution arrangement is provided which transfers oil onto a fin in the top wall of the worm gear housing where it flows into the spur gear housing and is distributed onto the spur gears.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view from a lower aspect of a single-suspension power driven staging, incorporating a high capacity winch unit characterizing the present invention;

FIG. 2 is a side view of a portion of the equipment illustrated in FIG. 1 with parts broken away for clarity;

FIG. 3 is a fragmentary section of a tilt control assembly incorporated in the equipment illustrated in FIG. 2;

FIG. 4 is a fragmentary plan view of the equipment illustrated in FIG. 1;

FIG. 5 is a cross'sectional view of a portion of the drive unit used in the equipment shown in FIG. 1, taken along the line 5-5 of FIG. 4 and with parts broken away for clarity;

FIG. 6 is an end elevation of the equipment shown in FIG. 5 and partly in cross-section as taken along the line 6-6 of FIG. 5;

FIG. 7 is an elevation view of the drive unit partly in section as taken along the line 7-7 of FIG. 6 and with parts broken away for clarity.

DESCRIPTION OF THE PREFERRED EMBODIMENTS With respect to a general description of the staging equipment incorporating a preferred embodiment of the invention, the staging comprises a frame 10 having an upper portion 12 and a lower portion 14. The upper portion includes an operators cage C having a deck D and mounting a fixed mast or tripod T having at the top thereof a wire rope guide or fairlead F. Wire rope R is led through the fairlead from a mounting on top of the building from which the staging is suspended. A winch unit W is mounted below the deck D in the lower portion of the frame and includes a power driven winch drum WD around which the wire rope is wound.

As is readily understood and as described in the aforesaid Fisher U.S. Pat. No. 2,998,094, this type of equipment is operator controlled and is designed to be suspended from a single wire rope along the side of a building, antenna structure, stack or the like. The

operator selectively can control up and down movement of the staging while riding in the cage C by means of an electric control panel P. It is important on this type of equipment, where safety and reliability of operation are required, that the wire rope R be wound onto and from the winch drum WD evenly and smoothly.

With reference to FIG. 1 the staging details are in many respects quite similar to those of the staging disclosed in the aforesaid Fisher U.S. Pat. No. 2,998,094 with the upper portion 12 of the frame 10 serving to support the operator and the tripod T providing a support for the fairlead F. The fairlead in the instant application includes three case-hardened pins, not shown, that guide the wire rope as it passes through the tripod. A tension holder 17 is fixed to the tripod just below the fairlead and includes two sets of vertically spaced rollers I8, 20. The wire rope R passes between the sets of rollers and one set is movable toward the other by a handle 21 to hold the wire rope and keep it from forming loose coils on the drum when the staging platform is rested on the ground. When the handle is released the rollers serve as additional low friction guides to position and reduce wear on the wire rope R.

As is best shown in FIGS. 1 and 2, the lower portion 14 of the staging frame I is provided with a rectangular bottom frame 22 which includes pairs of spaced lower and

upper cross braces

24 and 25, respectively. Each of the four cross braces is provided with a support plate 26 which mount two vertical braces 27 joining the lower and upper cross braces. An I-beam 28 is secured between each support plate 26 and vertical brace 27. As shown in FIG. 1 the I-beam is provided with two sets of vertically downwardly extending pin-mounting brackets 30 which are apertured to receive a pivot pin 32. Thus, two pivot pins are provided at spaced distances along the I-beam 28. Mounted for free pivotal movement on each pivot pin is a pivot block 34 that is formed integrally on each of two sets of webs or arms 36. The webs are spaced from one another to provide a central opening 38 which surrounds the I-beam 28 and are secured at their upper ends to a winch mounting plate 40. A support block 41 mounts a right hand, as viewed in FIG. 2, bearing block 42 and is fixed, as by welding, to the winch mounting plate. A left hand bearing block 44 is fixed to the other end of the winch mounting plate. The bearing blocks rotatably mount an axle 46 on which the winch drum WD is rigidly secured. An electric motor M and suitable driving gear, to be later described, are also secured to the winch mounting plate 40 for rotating the winch drum. The motor M is a suitable reversible electric motor or, in the alternative, may be an air motor or an internal combustion engine as disclosed in the aforesaid Fisher US. Pat. No. 2,998,094. The motor and drive gearing are suitable to rotate the winch drum at the desired speed to provide a vertical staging climbing rate of approximately 18 feet per minute. l-Iigher or lower speeds may, of course, also be obtained depending on the safety requirements and the type of service to which the staging is being employed.

As the wire rope R winds from end to end on the winch drum WD the drum will tend to flop or rock on the pivot pins 32 each time the wire rope R passes the vertical center line of the pivot pins. A tilt control assembly 50 is provided to dampen the intensity of this rocking action. As is best shown in FIGS. 2 and 3 the tilt control assembly 50 includes a cylinder 51 that is pivotally secured to the bottom frame 22. A control rod 52 is slidably received in a stepped-diameter abutment tube 53. A small collar or stop tube 53a of a soft metal, such as aluminum, is positioned on the control rod 52 at one end of the abutment tube 52 and serves as a positive stop to limit the pivotal movement of the winch unit W in one direction. The tilting of the winch unit W in the other direction is limited to a lesser degree by washer 59 resting on a tube 58 that is fixed to the cylinder 51. This is to compensate for the effect of the lay of the wire rope which is discussed later. The abutment tube 53 has an enlarged portion 53b that acts as a spring abutment for a secondary spring 54. A primary spring 55 circumscribes the control rod and abutment tube and engages a pair of spaced upper and lower washers 56a and 56b, respectively, secured to the control rod by adjustable nuts 57. The washers each engage a clip ring 58 secured in grooves in the ends of the cylinder 51. The free end of the control rod 52 is pinned for pivotal movement to the support block 41 on the right-hand end of the winch mounting plate 40. As may be readily seen in FIG. 2, pivotal movement of the winch unit w to the left about the pivot pins 32 will pull the control rod 52 against the lower washer 56b to compress the primary spring 55 against the upper washer 56a. As the winch unit continues to pivot toward the left the secondary spring 54 engages the upper washer 56a and is compressed against the enlarged portion 53b of the abutment tube 53. The secondary spring 54 engages the upper washer 56a only after the primary spring has undergone considerable compression and thus acts to immediately increase the resistance against further pivotal movement of the winch unit. This feature is important since the extra long length of the drum WD causes the wire rope R to move further out from the pivot point (pivot pins 32) of the winch unit and this substantially increases the lever arm and torque acting to pivot the winch unit. As the lever arm increases the secondary spring becomes engaged to counteract the increased torque and thus keeps the pivotal movement under control in all position. The stop tube or collar 53a engages the upper washer 56a when the unit has pivoted the maximum limit desired and prevents further pivoting in that direction. The stop tube may be easily replaced with a stop tube of a larger or smaller length to vary the pivotal limits.

Pivot movement of the winch unit W to the right, as viewed in FIG. 2, is also controlled. Pivotal movement in this direction will first compress the primary spring 55 between the upper and lower washers 56a and 56b and then will compress the secondary spring 54 as the pivotal movement continues. Finally the washer 59 will engage the tube 58 to prohibit further movement.

The pivotal movement of the winch drum WD with respect to the fairlead F is best shown in FIG. 2. In FIG.

2 an imaginary, vertical perpendicular line x has been drawn downward from the fairlead F to a horizontal plane y that passes through the center line or axis of rotation of the winch drum WD when the winch drum is in the horizontal position. With the drum horizontal the imaginary perpendicular line x and the plane y are at right angles with the wire rope as shown in FIG. 2

being vertically beneath the fairlead. The wire rope actually engages the drum or previously made coils on the drum on a tangent at plane y and-thus the fairlead is not directly above the drum. For the purpose of describing this invention, however, the angles discussed will be with reference to FIG. 2 it being assumed that the location of the fairlead with respect to the tangency of the rope on the drum may vary somewhat without affecting the operation of the device. It should also be noted that the fairlead is not over the center of the drum as viewed in FIG. 2. This is due to the fact that the lay of the individual strands of wire rope causes the wire rope to slip more easily when approaching one end of the drum than the other. It is for this reason that the movement of the winch unit W to the right is smaller than to the left which is accomplished by letting washer 59 contact tube 58. In the embodiment shown, for example, the right-hand end of the winch drum is spaced a further distance from fairlead and the imaginary perpendicular line x than the other. As shown in phantom lines in FIG. 2 the wire rope, indicated by phantom line R, has reached the right-hand end of the winch drum WD and in so doing has caused the winch unit W to pivot about the'pivot pins 32. As is readily seen the right-hand end of the winch drum has shifted to the left toward the imaginary perpendicular line x. Thus the angle between the imaginary perpendicular line x and the wire rope R in the phantom position is less than if the drum had been fixed. This, of course, causes the angle between the wire rope and the plane y, i.e., the fleet angle", to more closely approach the 90 right angle that is considered most desirable for winding the wire rope onto the winch drum.

It should be noted that other means for shifting the ends of the winch drum, such as a rack and pinion or the cam-type pivot shown in the Fisher US. Pat. No. 2,998,094, may also be used.

The pivot point of the drum WD in the preferred embodiment is approximately 18% inches below the axis of rotation of the drum. The length of the drum is 21 inches and the distance of its axis below the deck D and fairlead F are respectively about 8% and 70 inches.

In reaching the position indicated by the phantom line R at the end of the winch drum WD it can be seen that the lever arm, that is, the axial distance along the drum between the pivot pins 32 and the point at which the wire rope is wound on the drum, has steadily increased. As the electric motor M applies a constant tension on the wire rope the increase in this lever arm tend to increase the torque of the winch unit about the pivot point or pins 32. When the wire rope reaches the approximate location indicated by the reference character 70, which may vary to some degree, the secondary spring 54 in the tilt control assembly 50 comes in to play and provides an additional constantly increasing resistance to overcome and balance this increase in torque. Consequently a smooth pivotal movement of the winch unit about the pins 32 is maintained and flopping is eliminated.

The driving arrangement that permits distribution of the loading and improved oil lubrication for the enlarged, high capacity type winch unit W on the staging described is best shown in FIGS. 4-7. A drive unit includes three interconnected housings, namely, a spur gear housing 76, a worm gear housing 78 and a ring gear housing 80. As best shown in FIG. 7 a common vertical wall 82 interconnects the spur gear housing and the worm gear housing. A top wall 84, (FIG. 6), covers the worm gear housing and is provided with an oil transfer blade or fin 86, for a purpose to be later described, that terminates above a hollow tube 87 mounted in the common vertical wall 82 and passing into the spur gear housing. The tube 87 is cutaway to form a trough to catch the oil flowing from the fin 86.

The motor M is bolted to the spur gear housing 76 and includes an output shaft 90 having a spur pinion gear 91 keyed thereto. The pinion gear 91 drives a pair of spaced spur gears 92 which are keyed to a pair of rotatably mounted worm shafts 94. Each worm shaft includes a worm 96 which meshes with a worm gear 97 fixed on a common shaft 98. The common shaft is rotatably mounted in suitable hearings in the end walls of the worm gear housing 78. One end of the common shaft 98 extends into the ring gear housing 80 and has keyed to its free end a suitable bevel pinion 102. The bevel'pinion meshes with a bevel ring gear 104 that is keyed to the axle 46 of the winch drum WD. As is readily seen the loading of the worm gears is distributed between the two worms 96. Thus the dual worm gears reduce the tangential pressure and sliding friction between the worm gears and the worms to produce a substantial reduction in temperature rise and an increase in load capacity.

Oil dippers 110, made of any suitable material, such as synthetic, oil resistant rubber, include a plurality of peripherally spaced cups 112 which dip into an oil reservoir 114, common to the spur and

worm gear housings

76 and 78, and fling the oil onto the worms 96. The oil dippers are a supplementary lubricating feature and assist in oil distribution.

As is best shown in FIG. 6, the reservoir 114 is at the same level in each housing due to free flow through a port 116 in the common wall 82. The worm gears 97 and spur pinion gear 91 are lubricated by dipping into the reservoir and one worm and one spur gear are lubricated by direct transfer of the oil from the respective worm gear or spur pinion gear. For example, if the spur pinion gear is rotating clockwise, as viewed in FIG. 5, the left-hand spur gear will receive most of the oil carried from the reservoir 114 by the pinion. The righthand spur gear is lubricated by oil passing through the tube 87 that flows onto the pinion 91 and thus directly onto the right-hand spur gear. An additional reservoir 120 is provided in the ring gear housing to lubricate the ring gear 104 and the beveled pinion gear 102. As is thus readily apparent all parts of the driving gearing are effectively lubricated at all times. To still further increase cooling the worm gear housing 78 is provided with a plurality of fins 122 that dissipate heat generated into the surrounding ambient air.

It will be readily apparent that the motive power may be varied without effecting the principles of the invention. Likewise, it is of course to be kept in mind that the tolerable fleet angle variation in a specific installation depends to some extent on the nature of the cable or wire rope being used and the lay or wrap of the wire rope. It is well known that a given wire rope, for example, has a characteristic greater or lesser tendency to bunch or gap (slip) than other similar wire ropes and demands correspondingly greater or lesser control of fleet angle variation. Further, it is also well known that a given tendency to bunch or gap often exerts itself to a greater extent at one end of the winch drum more than at the other end, and it would be readily understood that the degree of compensation for the fleet angle variation contemplated by the present invention can be adjusted to maximize compensation where most needed. I

Having consider in detail the specific construction and operation of a preferred embodiment of the invention, various other modifications thereof will readily occur to those skilled in the art, within the spirit and scope of the following claims.

What is claimed is:

l. A winch mechanism for a suspended, power driven staging, comprising:

a staging frame having upper and lower portions;

an elongate winch drum mounted on said frame and having spaced ends and a central rotation axis between aid ends;

a fairlead fixed to said staging frame upper portion and positioned along an imaginary vertical line extending perpendicularly of said winch drum axis of rotation when in a horizontal position;

flexible rope means coiled around said winch drum;

means mounting said winch drum for rotation about said rotation axis;

movable means supporting said winch drum mounting means for enabling movement of a winch drum end towards said imaginary vertical line as said rope means coils toward said winch drum end; said movable supporting means comprising pivot means spaced below said winch drum axis of rotation; and a stop means for limiting said winch drum end movement toward said imaginary vertical line after a. predetermined amount of movement is obtained. 2. The winch mechanism defined by claim 1 further including a control assembly for resisting movement of I said drum end toward said imaginary vertical line.

3. The winch mechanism defined by claim 1 further including a control assembly for resisting tilting movement of said drum.

4. The winch mechanism definedby claim 3 wherein said control assembly includes primary resistance means for applying a constantly increasing force and secondary resistance means. operable when said drum rotation axis exceeds a predetermined angle.

5. The winch mechanism defined by claim 4 wherein said primary and secondary resistance means are compression springs.

6. The winch mechanism defined by claim 1 wherein the distance between said pivot means and said winch drum is greater than the half-length of said winch drum.

7. The winch mechanism defined byclaim 6 wherein said winch drum half-length is about 10.5 inches and said distance between said pivot means and said axis of rotation is about 18.5 inches.

Claims

1. A winch mechanism for a suspended, power driven staging, comprising: a staging frame having upper and lower portions; an elongate winch drum mounted on said frame and having spaced ends and a central rotation axis between aid ends; a fairlead fixed to said staging frame upper portion and positioned along an imaginary vertical line extending perpEndicularly of said winch drum axis of rotation when in a horizontal position; flexible rope means coiled around said winch drum; means mounting said winch drum for rotation about said rotation axis; movable means supporting said winch drum mounting means for enabling movement of a winch drum end towards said imaginary vertical line as said rope means coils toward said winch drum end; said movable supporting means comprising pivot means spaced below said winch drum axis of rotation; and stop means for limiting said winch drum end movement toward said imaginary vertical line after a predetermined amount of movement is obtained.

2. The winch mechanism defined by claim 1 further including a control assembly for resisting movement of said drum end toward said imaginary vertical line.

4. The winch mechanism defined by claim 3 wherein said control assembly includes primary resistance means for applying a constantly increasing force and secondary resistance means operable when said drum rotation axis exceeds a predetermined angle.

7. The winch mechanism defined by claim 6 wherein said winch drum half-length is about 10.5 inches and said distance between said pivot means and said axis of rotation is about 18.5 inches.