Title:
Vertical hoist assembly
United States Patent 3908801


Abstract:
A vertical hoist car assembly such as would be used in a large power plant chimney, a silo, a dam structure, or the like, is disclosed. The assembly includes a ladder shaped guide track having parallel side rails interconnected by longitudinally spaced rungs. A service car is arranged to be moved on the guide track and is provided with upper and lower wheels arranged to engage the side rails. The service car has an opening in its floor sized for personnel to enter or leave the car. A hinged door covers the opening during normal operation of the car. In the event of a power failure or some other problem when the service car is unable to move and is at some point intermediate the ends of the guide track, the operator may open the floor door and leave the car and descend down the ladder shaped guide track.



Inventors:
POHLMAN JOE C
Application Number:
05/450561
Publication Date:
09/30/1975
Filing Date:
03/13/1974
Assignee:
VERTICAL TRANSPORT COMPANY
Primary Class:
Other Classes:
182/103, 182/112, 187/372, 187/376, 188/189
International Classes:
B66B5/04; B66B5/22; B66B11/02; (IPC1-7): B66B5/24
Field of Search:
187/1,2,6,8,12,13,14,80,81,85,86,87,88,89,90 182
View Patent Images:
US Patent References:
3282383Free-fall safety brake1966-11-01Chasar
3177543Safety locking device1965-04-13Fountain
2618361Safety mechanism for elevators1952-11-18Zindt
2561514Strand brake1951-07-24Houseman
2326046Elevator safety apparatus1943-08-03McCormick
2249900Extension ladder and elevator1941-07-22Honig
2232890Derrick elevator1941-02-25Stillwagon
1163239N/A1915-12-07Iron
0519118N/A1894-05-01
0478169N/A1892-07-05
0455536N/A1891-07-07
0303337N/A1884-08-12



Primary Examiner:
Blunk, Evon C.
Assistant Examiner:
Rowland, James L.
Attorney, Agent or Firm:
Bogdon, Paul
Claims:
I claim

1. A vertical hoist car assembly for use in upwardly tapering structures and for travelling along a generally upright course therein, comprising

2. A vertical hoist car assembly as set forth in claim 1 including overspeed safety means on said service car operative with said braking means for activating said braking means into braking engagement with said side rails when said service car exceeds a predetermined downward speed.

3. A vertical hoist car assembly as set forth in claim 2 wherein said overspeed safety means is operatively connected with said safety cable to sense the speed of said service car.

4. A vertical hoist car assembly as set forth in claim 1 whereby the floor of said service car is generally flat; and wherein said door is a generally flat plate member pivotally arranged to open upwardly and to close in a generally coplanar relationship to said floor.

5. A vertical hoist car assembly as set forth in claim 1 wherein said suspension means includes at least two cables fixed at opposite corner regions of the top portion of said service car; said braking means includes first and second brake shoe assemblies, each fixed to a side section of said service car; each brake shoe assembly having an upwardly extending rod, a brake shoe connected with said rod, a pressure biased lever connected with said rod urging said brake shoe into braking engagement with said side rail; and wherein one each of said levers is connected to a said cable such that when said cable is under tension said brake shoe is disengaged from said side rail.

6. A vertical hoist car assembly as set forth in claim 1 wherein said wheels are arranged to engage the outer side surface areas of said service car is prevented from lateral movement with respect to said track means.

Description:
BACKGROUND OF THE INVENTION

In various types of tall structures such a power plant chimneys, hydroelectric power station dams, and the like, a vertical hoist service car installation is provided for travel of personnel from the bottom to the top of the structures. Typical of such a service car installation is that described in U.S. Pat. No. 3,517,775 issued to Roy E. Meyer. It is necessary that an alternative way for operating personnel to descend from the service car be provided in these tall structures in the event that the service car becomes inoperable, such as would occur for example during a power failure or where a suspension cable breaks. Various alternate descent arrangements have been devised all of which have proven to be inadequate or undesirable in some manner. In power plant chimneys fixed ladders are mounted on the inner wall with horizontal platforms being spaced within the chimney at longitudinal intervals. Because of the tapered construction of the chimneys the ladders are generally not close enough to the service car for easy and safe transfer of the personnel from the car to the ladder. However, if the service car is stopped near a platform the operator only need step out of the car and onto the platform and then onto the fixed ladder. On the other hand, if the car stops mid-way between platforms, the operator must first lower himself onto the next lower platform. Various boatswain's chair-type rope and pulley arrangements which hook to the service car are available for the operator to lower himself onto a platform. These lowering arrangements are generally cumbersome in their respective operations and not altogether safe. In their operations, the lowering arrangements allow the operators to descend vertically from the service car. Since the chimneys are tapered the operator would have to swing over to the next lower platform. In some cases the operator might have to swing a substantial and unsafe distance to the platform. Compounding this dangerous condition is the fact that most chimneys have intermittent lighting inside causing poor visibility, and should there be a power failure there would be no light at all.

The present invention overcomes the above noted deficiencies as well as others, in alternative descent arrangements by providing a vertical hoist car assembly which includes as part of its makeup a quick, efficient, and safe way for an operator to leave a stopped service car to descend therefrom. By virtue of the present invention, an operator merely hooks himself onto a safety cable, goes through an opening in the floor of the service car, gets onto a ladder which serves normally as the guide tracks for the car, and descends on the ladder as quickly as he is able to. The following summary gives a more specific description of the present invention.

SUMMARY OF THE INVENTION

The present invention provides a vertical hoist car assembly for travelling along a generally upright course which preferably comprises: elongated track means having a ladder construction of two generally parallel side rails interconnected by a plurality of transversely extending longitudinally spaced rungs; support means for supporting the track means in an upright manner on an upright surface, such as a chimney wall; a service car for moving along the upright course, the car having upper and lower wheels arranged and constructed to engage the side rails of the track means, the car having a floor at the lower end portion thereof with the floor being provided with an opening sized for ready entrance and exit by operating personnel, and a door covering the opening; suspension means, such as cables, for suspending the car on the track; and power means for supporting the suspension means and for lifting and lowering the car.

In its preferred form the present invention includes a safety cable extending between the upper and lower end regions of the track. The safety cable is arranged so that an operator who is descending on the ladder track may easily clamp a safety belt onto the cable. The preferred form of the invention also includes brakes which are arranged to engage the side rails of the guide tracks. The brakes are operable with the suspension cables and are arranged to be disengaged from the side rails when the suspension cables are under tension and to engage the side rails in the event either suspension cable loses tension as would happen when a cable breaks. An overspeed device is also provided on the preferred form of this invention, and is arranged to activate the brakes when a predetermined downward speed of the service car is exceeded.

Various other advantages, details, and modifications of the present invention will become apparent as the following description of a present preferred embodiment thereof proceeds.

BRIEF DESCRIPTION OF THE DRAWING

In the accompanying drawings I have shown a present preferred embodiment of the present invention in which:

FIG. 1 is a front elevation view of a vertical hoist car assembly embodying the present invention;

FIG. 2 is a side elevation view of the assembly of FIG. 1;

FIG. 3 is an enlarged sectional view looking along the lines III--III of FIG. 1 and showing in more detail the track-engaging wheels of the invention;

FIG. 4 is an enlarged sectional view looking along the lines IV--IV of FIG. 1 and showing in more detail the doors of the invention;

FIG. 5 is an enlarged front elevation view of the braking assembly of this invention with parts removed to show details of construction;

FIGS. 6 and 7 are enlarged front elevation and plan views of the brake shoe arrangement of the braking assembly shown in FIG. 5;

FIG. 8 is an enlarged plan view of the cable lever and arrangement of the braking assembly shown in FIG. 5 with certain parts deleted for clarity of illustration;

FIG. 9 is a front elevation view of the overspeed trip linkages of FIG. 5;

FIG. 10 is a vertical sectional view looking along the line X--X of FIG. 9 and FIG. 11 is a vertical sectional view looking along the lines XI--XI of FIG. 5.

Referring now to the drawings, there is represented in FIGS. 1 and 2 a vertical hoist car assembly 10 of the type which would be installed in an electric generating power plant chimney. The vertical hoist car assembly 10 is used for ascending along the inner surface of the tapered chimney wall 12 so that operating personnel may maintain, inspect, and/or service the chimney, stack, or other auxiliary equipment found within the chimney structure. As is well known, power plant chimneys, which may range from between 750 feet and 1,250 feet in height, are provided with regularly longitudinally spaced horizontal work platforms and one or more permanently fixed ladders extending along the inner walls of the chimney. The work platforms might be spaced anywhere from 120 feet to 200 feet apart and are sized to accommodate work personnel.

The vertical hoist car assembly 10 includes an elongated track 14 extending along and spaced from the wall 12 from the top to the bottom floor of the chimney. The track 14 is in the form of a ladder which includes a pair of generally parallel and elongated generally square cross-section shaped side rails 16 and 18 interconnected by means of a plurality of transversely extending and longitudinally spaced rungs 20. The track 14 is supported by a series of angle shaped brackets 22, shown clearly in FIG. 3 fixed to the wall 12 by means of an anchor bolt 24. Pads 26 secured at one end to the inner surface of side rails 16 and 18 are secured as by welding or the like at their other ends to the brackets 22.

The side rails 16 and 18 are spaced in such a manner as to accurately guide the ascent and descent of hoist service car 30 which includes a rigid box shaped framework 32 upon which is attached peripheral screening 34 defining enclosed sides of the car. The framework 32 is constructed to form an upper chamber 36 which houses certain equipment to be described later, and a lower chamber 38 sized to accommodate operating personnel. The lower chamber 38 is provided with a floor section 40 having a centrally located large opening 42 therethrough sized for entrance and exit by an operator. The opening 42 as shown in FIG. 4 is normally closed by a hinge mounted door 44. The framework 32, floor 40, and opening 42 are so constructed and arranged such that an operator may conveniently leave the car 30 through the opening 42 and step onto the rungs 20 of the track 14 to descend therealong. Normal entrance and exiting of lower chamber 38 of the car 30 is made through a hinged upright door 46 provided on the side of the car as shown in FIGS. 2 and 4.

The car 30 is guided on track 14 along the side rails 16 and 18 by upper and lower wheel assemblies 50 and 52, respectively. FIG. 3 shows the arrangement of lower wheel assemblies 52 which are essentially the same as that of the upper wheel assemblies 50. Each lower wheel assembly 52 includes a pair of grooved wheels 54 mounted with their axes of rotation at an angle to each other on an angled bracket 56 fixed to a lower side edge portion of the framework 32 of car 30. The wheels 54, as shown in FIG. 3, are shaped and arranged to engage and roll along the inner and outer side edges of the side rails 16 and 18. The upper wheel assemblies 50 are similarly constructed and arranged.

The car 30 is suspended and driven along the tracks 14 by a power drive assembly which includes a pair of cables 60 attached at one of their ends to brake levers, shown in FIG. 5, and located at an upper region of the framework 32 (the brake levers will be described more fully hereinafter), and from those points extend upwardly around idler sheaves 62 which are mounted for rotation on identical angle iron shaped brackets 64 extending radially inwardly from the upper end of chimney wall 12 and secured thereto by means of bolt assemblies embedded in the wall. From the sheaves 62 the cables 60 extend downwardly adjacent the wall 12 through guide sheaves 68 shown in FIG. 3 mounted for rotation on plates 70 fixed to brackets 22. U-shaped keeper bars 72 are supported on the mounting shafts 71 of the guide sheaves 70 to keep the cables 60 in their vertical positions. The cables 60 are reeved around idler sheaves 74, one of which is shown in FIG. 2, mounted for rotation in supports 76 fixed to the floor surface. From idler sheaves 74 the cables 60 extend generally horizontally around a traction drive machine 78 mounted on the floor surface for rotation about a horizontal axis. The cables 60 extend generally horizontally from traction drive machine 78 to a floor mounted idler sheave 80 and thence upwardly to the car where they are secured to lower end regions of the framework 32. An electrically powered traction reversible drive motor 82 is operatively connected with traction drive machine 78 and provides the necessary drive force for raising and lowering the car 30 along the guide track 14. The operation of drive motor 82 is controlled by the operator in the service car 30 by activating the appropriate controls mounted therein. Control signals are transmitted to drive motor 82 through cable 85 wound around recoil reel 83 which is constructed to pay out and wind up the cable 85 depending on the direction of movement of the service car 30.

A safety cable 84 extends between the ends of the guide track 14 and is fixed at its upper end to a bracket 86 secured to the uppermost rung 20 of the guide track and at its lower end to a bracket 88 secured to the lowermost rung 20 of the guide track. A spring-type tensioning device 90, is secured between the floor and the lower end of the safety cable 84 for the purpose of adjusting the tension on the safety cable. An operator who has a need to leave the car 30 through the opening 42 in the floor 40 and descend on the rungs 20 may clamp a safety belt to the safety cable 84 to insure his safe descent. An added function of the safety cable 84 is to serve to transmit the speed of the car 30 to an overspeed device which will be more fully described hereafter.

A braking system is provided to stop the car 30 in the event one or both of the cables 60 breaks or otherwise loses tension, or in the event the car exceeds a predetermined downward speed (i.e. overspeeds). The braking system includes a pair of identical brake assemblies 94 each as shown in FIGS. 5-7 having a housing 95 containing sliding wedge shaped brake shoe 96 with a series of teeth on its inner edge surface. The brake shoe 96 is arranged to translate upwardly and downwardly along an angular path defined by the angularly arranged surface 97 formed inside of the housing 95. The housings 95 are secured to the framework 32 of car 30 in a manner such that the toothed edge of the brake shoes 96 are disposed adjacent the front surface surface of the side rails 16 and 18. Thus, when the brake shoes 96 are moved upwardly they will engage the side rails 16 and 18 to stop the descent of the car 30. Each brake shoe 96 is connected to an upwardly extending pull rod 100 with both rods being fixed, as clearly shown in FIGS. 5 and 9 at their upper ends to horizontally arranged braking levers 102 both of which levers are pivotally secured at their outer ends to the floor 104 of the upper chamber 36 of car 30. The inner ends of the braking levers 102, that is the ends towards the center of the floor 104, are arranged within the confines of a pair of upwardly extending parallel guide bars 106 fixed to floor 104 as clearly shown in FIGS. 9 and 10. Pin 105 joins the inner ends of braking levers 102 with the pin being arranged within lower slots 107 formed in the guide bars 106. The brake shoes 96 are arranged within housing 95, and their weights are such that the shoes, if not urged upwardly by some external force, would drop to the lowermost position of the housing 95 and be disengaged from the side rails 16 and 18. Accordingly, the upward urging of the braking levers 102 would result in the brake shoes 96 being drawn into braking engagement with the side bars 16 and 18. For this purpose, the braking levers 102 are connected as shown in FIG. 10 at their inner ends to the lower end of an elongated actuator shaft 108, the pin 105 securing the shaft and levers. A pin 109 is fixed to the upper end of the actuator shaft 108 the pin in turn being disposed to fit in an upper slot 110 through the upper end portion of guide bars 106. An overspeed actuator unit 111 is fixed to an intermediate portion of the actuator shaft 108 and is arranged within intermediate slots 112 through the guide bars 106. The overspeed actuator unit 111 is in the form of a finger which extends outwardly of the left guide bar 106 as shown in FIG. 10, the finger being arranged to be engaged by an overspeed trip arm as will be more fully described hereinafter. Cable trip arm assemblies 114 are connected to the upper end portion of the actuator shaft 108, each assembly including an arm 115. The inner ends of the arms 115 have fixed thereto an I member 117 each of which I member has a longitudinal slot 118 arranged to extend coextensively with upper slots 110 of the guide bars 106. Pin 109 extends transversely through slots 110 and 118 to secure the guide bars 106, actuator shaft 108, and trip arms 115 in upward and downward slidable relationship with each other. As shown in FIGS. 5-7, the brake shoes 94 are disengaged from side rails 16 and 18. In the disengaged relationship, the trip arms 115 position the I members 117 so that the pin 109 is at the lowermost position of the slots 118 in the I members. When the trip arms 115 are pivoted upwardly the I members 117 will engage the pin 109 to urge the actuator shaft 108 upwardly, thus pivoting the brake levers 102 upwardly thereby moving the pull rods 100 and brake shoes 94 upwardly to engage the side rails 16 and 18. The trip arms 115 are placed under an upwardly directed force by a pair of compression actuators 120 which include a plunger arm 121 fixed at the respective upper ends to intermediate sections of lift cranks 122 which have their inner ends fixed to rotatable shafts 123 supported in vertical members 124 and 125 fixed at their lower ends to floor 104 of the upper chamber 36. The outer ends of trip arms 115 are fixed to intermediate sections of the rotatable shafts 123. Thus, when the lift cranks 122 are urged downwardly the rotatable shafts 123 will rotate the trip arms 115 upwardly to ultimately cause the brake shoes 94 to engage the side rails 16 and 18. The plunger arms 121 are under a downwardly directed force transmitted to it by compression springs arranged within housings 125 which are fixed in position to support members 126 secured to floor 104 of upper chamber 36.

As shown in the drawings the support cables 60 are connected to the trip arms 115 through the lift cranks 122 and thereby the weight of car 30 acting on the cables results in the trip arms being pulled upwardly against the downward forces of the compression actuators 120 thus disengaging the brake shoes 94. In the event that either or both support cables 60 break either or both of the compression actuators 120 will cause one or both trip arms 115 to rotate downwardly resulting in the engaging of both brake shoes 94 with the side rails 16 and 18. In other words, if one support cable breaks both brake shoes 94 are caused to engage. Similarly, if both cables break both brake shoes would engage.

An emergency overspeed actuator 130 is provided and includes a rotatable overspeed governor 132 of common and wellknown construction mounted centrally on floor 104. The speed of travel of the car 30 is transmitted to the governor 132 by the safety cable 84 which is reeved around the governor through idler sheaves 134 and 136 mounted on the car 30 in the manner shown in FIGS. 5, 8, and 11. The governor 132 has flyweights 138 which are arranged to move radially outwardly as the speed of the car 30 increases. A rotatable and normally stationary trip arm 140 is arranged to be engaged by a flyweight 138 at the overspeed radial position of the extended flyweight. Thus, when a predetermined downward speed of the car 30 is exceeded the flyweights 138 will travel radially outwardly to engage and move trip arm 140 to thence engage the overspeed actuator unit 111 connected to actuator shaft 108 thereby to move the actuator shaft upwardly causing brake shoes 94 to engage the side rails 16 and 18. Thus, the emergency overspeed actuator 130 provides insurance for braking the car 30 in the event of any malfunctions that would cause downward overspeed of the car 30.

It should now be clearly apparent how the present invention provides the advantages of safety in a vertical hoist car assembly as delineated in the introductory portion of this description. It should be further apparent that those safety advantages are provided by a simple arrangement of elements. This is true especially in the braking system of the invention as compared with braking systems heretofore used in vertical hoist car assemblies.

While I have shown and described a present preferred embodiment of this invention, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied within the scope of the following claims.