US3848706A

US3848706A - Lift apparatus

Info

Publication number: US3848706A
Application number: US00421713A
Authority: US
Inventors: R Darwent
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1973-12-03
Filing date: 1973-12-03
Publication date: 1974-11-19
Anticipated expiration: 1991-11-19
Also published as: CA999817A

Abstract

Lift apparatus for mounting in a structure having spaced guide rails, including a platform mounted for guided movement in the structure via guide elements which coact with the guide rails, and including safety devices which operate on the guide rails. The safety devices are suitable for a brake on a construction platform, or as a governor operated safety on an elevator car. The safety devices each include a circular cam, an actuating arm pivotally mounted coaxial with the circular cam, and a roller on the actuating arm which follows the circular cam when the actuating arm is pivoted to its actuated position, to engage the associated guide rail.

Description

United States Patent Darwent Nov. 19, 1974 LIFT APPARATUS [75] Inventor: Richard H. Darwent, Hopatcong, Primary Exami',1er EVOn Blunk NJ Assistant Exammer.lames L. Rowland Attorney, Agent, or FirmD. R. Lackey [73] Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa.

Filed: Dec. 3, 1973 Appl. No.: 421,713

US. Cl. 187/86, 188/189 Int. Cl B66b 5/18 Field of Search 187/80, 81, 86, 87, 88,

References Cited UNITED STATES PATENTS [57] ABSTRACT Lift apparatus for mounting in a structure having spaced guide rails, including a platform mounted for guided movement in the structure via guide elements which coact with the guide rails, and including safety devices which operate on the guide rails. The safety devices are suitable for a brake on a construction platform, or as a governor operated safety on an elevator car. The safety devices each include a circular cam, an actuating arm pivotally mounted coaxial with the circular cam, and a roller on the actuating arm which follows the circular cam when the actuating arm is pivoted to its actuated position, to engage the associated guide rail.

7 Claims, 4 Drawing Figures PATENTEL F13V19|974 SHEET 10; 3 3,848,706

RELEASE 22 FIG. I

PATENTE-U nav 1 91974 sum 2 or 3 LIFT APPARATUS BACKGROUND OF THE INVENTION I. Field of the Invention:

The invention relates to lift apparatus, such as elevator systems, including construction platforms for use in the construction of elevator systems.

2. Description of the Prior Art:

During the construction of an elevator system, it is common to install a work platform in the hoistway to transport construction personnel and equipment to the various floors and penthouse of the associated building. The construction platform requires a simple, rugged brake for holding a selected position on the guide rails, and it would be desirable to provide a brake which may be easily modified to operate as a Type A (instantaneous) safety, as identified in American National Safety Standard Code For Elevators (ANSI Al7.1- 1971), for use in elevator systems having a rated speed of not more than 150 feet per minute. It is desirable for this type of safety to set in as short as time as possible after actuation, so the speed and energy of the car will be lower, stopping the car in a shorter distance. Thus, it would be desirable to provide a new and improved Type A safety for elevator systems, which has the advantage of setting with minimal delay when governor actuated, and which may be easily adapted for function as a brake for an elevator construction platform.

SUMMARY OF THE INVENTION Briefly, the present invention is new and improved lift apparatus which includes a new and improved brake for a construction platform, which operates from guide rails to be subsequently used for an elevator car. The brake may be modified to be actuated by a governor rope, and as such functions as a new and improved Type A safety for elevator systems, which sets very quickly after actuation.

The brake for the construction platform operates on the guide rails, and includes a mounting member having a back up plate and a circular cam attached thereto, which are disposed such that they are spaced from different opposed side guide surfaces of a guide rail. An actuating arm is pivotally mounted coaxial with the circular cam, with the outer end of the actuating arm carrying a shaft mounted roller. In the brake application, the actuating arm is biased to the set position in which the roller is forced up the circular cam until it engages the adjacent side guide surface of the guide rail. A predetermined clearance is deliberately provided between the inside diameter of an opening through the roller and the outside diameter of the shaft on which the roller is mounted, such that the actuating arm merely positions the roller and does not carry any load.

The brake may be modified for use as a new and improved safety for elevator systems by operating the arm with the governor rope. The circular cam reduces the distance the roller must travel when the safety is actuated, compared with the use of a straight incline, while maintaining the same rail clearance. The shorter travel distance of the roller allows the safety to set in a slightly shorter time after actuation, so the car speed and energy should be lower when the roller engages the rail. The circular cam also reduces the overall height of the safety, reducing the size and weight of the safety.

BRIEF DESCRIPTION OF THE DRAWINGS The invention may be better understood, and further advantages and uses thereof more readily apparent, when considered in view of the following detailed description of exemplary embodiments, taken with the accompanying drawings, in which:

FIG. 1 is an elevational view of a new and improved construction platform which includes a brake constructed according to the teachings of the invention;

FIG. 2 is an partially exploded perspective view of the brake shown in FIG. 1;

FIG. 3 is a diagrammatic view of an elevator system which may employ the brake shown in FIGS. 1 and 2 as a new and improved safety; and

FIG. 4 is a perspective view of a safety constructed according to the teachings of the invention, which may be used with the elevator system shown in FIG. 3.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawings, and FIG. 1 in particular, there is shown a new and improved construction platform 10 which includes a guiding system and safety brake constructed according to the teachings of the invention. The platform 10 is installed in the hatch or hoistway of an elevator system during the installation thereof, and uses the two spaced elevator car guide rails, such as guide rail 12, to coact with in performing the guiding and braking functions.

Platform 10 includes a frame 11 having a base 14 for supporting personnel and equipment to be vertically transported through the hoistway, which is connected to the lift means 16 via any conventional roping arrangement. The lift means 16 may be a temporary hoist. The frame 11 includes a lower guide and safety arrangement 18 supported from the base 14 by a plurality of structural members, such as

members

20 and 22. Each side of the frame 11 which faces a guide rail, such as guide rail 12, includes two spaced

angle members

24 and 26, with the space 28 between them being selected to receive the nose 30 of the guide rail 12 with a predetermined clearance.

Cross members 32 and 34, secured to

members

20 and 22, and similar cross members on the opposite side of the frame 11, support the lower guide assembly and safety arrangement 18.

The guide system of platform 10 includes upper and

lower guide elements

40 and 42 which coact with the guide rail 12, and upper and lower guide elements, similar to guide

elements

40 and 42, which coact'with the other guide rail. The guide elements of a construction platform must not occupy the space immediately adjacent to the face guide surface of the guide rails, as vertical plumb lines are disposed in this space in order to align the rails and brackets.

The the guide and safety assembly 18, on each side of the movable work platform 10 includes a safety brake device, such as safety brake device 110, which is shownin a partially exploded perspective view in FIG.

2. Safety brake device in the platform application shown in FIG. 1 is not used as an automatic safety, but its construction lends itself for use as a new'and improved governor operated Type A (instantaneous) safety in an elevator system, as will be hereinafter described.

1 12.mounted on the cross members '32 and 34. A'backup plate member 114 and a circular cam member 116 are fixed to base 112 in predetermined spaced relation. The circular cam member is a tubular cylindrical member having an opening 117 which extends between its ends. The back-up plate 1 14 is located to provide about 0.060 inch clearance between one of its sides and the side guide surface 54 of guide rail 12. The circular cam 116 is disposed adjacent to but spaced from the other side guide surface 52 of the guide rail 12.

An actuating arm 118 having first and

second ends

119 and 121 is pivotally mounted on base 112, with the pivot axis being concentric with the centerline 120 of the circular cam 116. Actuating arm 118 is joumaled to one end of a shaft member 122, such as via bearings shown generally at 124, and the other end of shaft 122 is disposed through the opening 117 in cam member 116 and fixed to the mounting base 112. Shaft

members

126 and 128 each have one end fixed to the actuating arm 118 and their other ends extend outwardly from arm 118 in spaced relation from opposite sides of shaft 122 such that they both enter opening 117 with a predetermined small clearance between their outside diameters and the inside diameter of opening 117. This arrangement enables the actuating arm 118 to pivot about the shaft 122, with the

shafts

126 and 128 providing guides on the inside diameter of the opening 117 which limit the amount shaft 122 can bend. This arrangement substantially reduces the size of the bearings required for the application. An alternative construction would be to fix the shaft 122 to the actuating arm 118 and to journal the other end of the shaft into the mounting base 112.

A shaft member 130 is fixed adjacent to end 121 of actuating arm 118, and a roller 132 having an opening 134 therein is telescoped over the shaft 130 and retained thereon, such as with a flexible C-washer (not shown), which is snapped into groove 136 adjacent the outer end of the shaft 130. It is important that the outside diameter of shaft 130 be smaller than the inside diameter of the opening 134 in roller 132, which arrangement enables the actuating arm 118 and shaft 130 to position the roller 132, but to remain free of load, as will be hereinafter explained. A shaft diameter of 0.38 inch and an inside diameter of 0.5 inch for opening 134, for a total clearance of 0.120 inch, have been found to be satisfactory.

The outisde diameter of cam 116, the location of cam 116 on the mounting base 112, the spacing 138 between the centerlines of

shaft members

122 and 130,

and the diameter of roller 134, are all selected such that a counterclockwise pivotal movement of shaft 118 about axis 120 will force roller 132 about the outside surface of the circular cam until the roller engages the side surface 52 of the guide rail 12. This engaged position of roller 132 is shown in phantom in FIG. 2. The roller 132 is forced between cam 116 and the guide rail 12, and the guide rail is forced against the back-up plate 114, providing a braking force which operates upon the rail 12. The clearance between the shaft 130 and inside diameter of roller 132, as hereinbefore pointed out, is made sufficient such that all forces are transmitted between the cam 116, roller 132, rail 12, and back-up plate 114, isolating the shaft 130 and the arm 118 from load.

In the application of the safety brake 1 to the construction platform 10, the brake is normally set, with the actuating arm biasing roller 132 against rail 12 to hold the platform 10 to the guide rails. The brake is released when it is desired to move the platform via the connected hoist apparatus.

FIG. 1 illustrates suitable means 140 for biasing the brake 110 to its set position against the rail 12. Means 140 includes a compression spring member 142, a spring seat 144 which is fixed to the mounting base 112, a shaft member 146 which is operated by the spring 142, and means coupling the shaft 146 to the end 1 19 of actuating arm 118, such as a shaft 148 fixed adjacent to end 119 of arm 118, a collar 149 disposed about shaft 146, with the collar having outwardly extending portions with openings therein for receiving shaft 148, and means for securing the collar to the shaft 146, such as

nuts

150 and 152. A washer member 154 is disposed over end of shaft 146 which extends through the spring 142, with the washer member 154 providing a spring seat. Nuts 156 are threadably engaged with shaft 146 to compress the spring 142 and exert a downward force on shaft 146 which urges the actuating arm 1 18 counterclockwise to position the roller 132 against the guide rail 12. When it is desired to release the brake 110, the shaft 146 is pulled upwardly, such as via a release wire 160, overcoming the spring bias and pivoting arm 118 clockwise to disengage roller 132 from the rail.

The brake 110 illustrated with the construction platform 10 also has advantages when used as a Type A safety for an elevator system. FIG. 3 is a diagrammatic illustration of an elevator system which may utilize the brake 110 as a Type A safety. Elevator system 170 includes an elevator car 172 and a counterweight 174 suspended in the hoistway 173 of an associated building or structure 175, via opposite ends of cables or ropes 176 which are reeved over a traction sheave 178. Traction sheave 178 is driven by a suitable elevator drive motor (not shown). A centrifugal force governor 180 is driven by a governor rope 182 connected to new and improved safety brake 110 mounted on the elevator car 172. The safety brake 110 includes substantially identical safeties at either end of the safety channels 183, which safeties are interconnected by a flexible link 185. The safety brake is referred to with a reference numeral 110' in this embodiment, since it is slightly modified compared with the embodiment of the brake wherein it is used with the construction platform, as will hereinafter be described. The loop of governor rope 182 passes about a pulley 184 located at the bottom of the hoistway 173. The safety 110' operates on

guide rails

186 and 188, from which the elevator car 172 is guided.

As the elevator car 172 travels up and down the hoistway 173, the rope 182 drives the governor at a speed proportional to the speed of the elevator car. If the car speed exceeds a predetermined value during its downward travel, the governor 180 grasps the governor rope 182. The resultant relative movement between the rope 182 and the elevator car 172 actuates the safety 110'.

FIG. 4 is a perspective view of safety 110. Since the safeties at either end of the safety channels 183 are similar, only the safety at the end which is connected to the governor rope 182 is shown. Like reference numerals in FIGS. 2 and 4 refer to like components, and will not be described again in detail. Like reference numerals except for a prime mark indicate that the component has been modified for the elevator application of the safety.

The base 112 has mounting

lugs

190 and 192 fastened to the back side thereof, and the safety 110 is mounted for pivotal movement by a king pin 194 disposed through the openings in the lugs. The king pin 194 has its ends joumaled to the safety channels.

Since the safety 110' is set when the elevator car is moving downwardly and the governor rope 182 is grabbed by the governor 180, the actuating arm 118 is modified to apply the rope force adjacent to end 121 of the actuating arm 118', and the end 119 does not include any means for pivoting the actuating arm. The rope 182 is secured to the outer surface of actuating arm 118 by any suitable means, such as by a U-shaped strap l96held by a pair of threaded shaft and nut combinations 198. The rope 182 is fastened to actuating arm 1 18 with the actuating arm in the unactuated position. As long as the governor 180 does not grab the governor rope 182, the safety 110 will maintain this unset condition. When the governor grabs the governor rope, the relative motion between the downwardly moving elevator car and the governor rope will pull the actuating arm 118' upwardly, forcing roller 132 about the circular cam 116 and into engagement with the guide rail 186. Frictional engagement between the roller 132 and guide rail 186 drives the roller further up the cam 1165, providing a wedging effect which forces the rail into the back-up plate 114. All of the braking forces are transmitted through-the cam 116, roller 132, rail 186, and back-up plate 114, with little or no force being applied to the actuating arm 118. Thus, the actuating arm 118 merely positions the roller in its set position, and, due to the clearance between the outside diameter of shaft 130, and the inside diameter of the roller 132, there are no forces transmitted to the actuating arm.

The safety 110 has many advantages in the elevator application. The circular cam 116 makes it possible to reduce the vertical height of the jaw assembly compared with the construction which uses an inclined plane, while maintaining the same rail clearances. Further, the distance the roller 132 travels when it is actu-- ated is less than the actuating distance used with inclined plane type safeties, allowing the disclosed safety to set quicker Thus, the car speed and energy of the car will be less when the safety engages the rail, allowing the car to be stopped in a shorter distance. The safety is manufactured from simple shapes, which are rugged yet easily machined and fabricated.

The cam member 116 is referred to in the specification as a circular cam, because it is most easily machined and fabricated in this shape. However, it is to be understood that only a portion of its cross-sectional configuration need follow the arc of a circle, i.e., the portion to be traversed by the roller 132 between its unactuated and set positions.

I claim as my invention:

1. Lift apparatus comprising:

a structure including first and second spaced guide rails, each of said guide rails having first and second opposed side guide surfaces,

and first and second safety devices carried by a platform which operative on said first and second guide rails, respectively,

each of said safety devices including a back-up plate, and a cam member having a circular portion, said back-up plate and cam member being disposed adjacent to but spaced from the first and second side guide surfaces, respectively, of a guide rail, an actuating arm, means pivotally mounting said actuating arm coaxial with the circular portion of said cam member, and a roller carried by said actuating arm,

said actuating arm, when pivoted about a predetermined angle, directing said roller about the circular portion of said cam member into engagement with the second side guide surface of its associated guide rail, said actuating arm and roller having a predetermined clearance between their engaging surfaces selected to enable the actuating am to position the roller against the guide rail while being isolated from forces generated between the engaging cam member, roller, guide rail and back-up plate.

2. The lift apparatus of claim 1, wherein each of the safety devices includes bias means, said bias means biasing the actuating arm to its actuated position with the roller against the second side surface of the guide rail, and means for overcoming the bias means to pivot the actuating arm to its unactuated position and release the roller from its position against the guide rail.

3. The lift apparatus of claim 2, wherein the cam member is a cylindrical member having first and second ends and an opening which extends between its ends, and the means pivotally mounting the actuating arm coaxial with the cam member includes a shaft member fixed to the mounting base and extending coaxially outward through the opening in the cylindrical cam member with its outwardly extending end journaled to the actuating arm.

4. The lift apparatus of claim 3, including guide members fixed to the actuating arm which extend into the opening of the cylindrical cam member immediately adjacent the inner surface thereof, to guide the pivotal movement of the actuating arm from the inner surface of the cylindrical cam member.

5. The lift apparatus of claim 1, including means interconnecting the actuating arms of the first and second safety devices, and actuating means connected to the actuating arm of one of the first and second safety devices, said actuating means being operative to pivot the actuating arms in unison and direct the rollers of the first and second safety devices into engagement with the first and second guide rails, respectively.

6. The lift apparatus of claim 1, wherein the platform includes an elevator car, and including a governor device including a governor rope which moves with the car until an overspeed condition is detected, means interconnecting the actuating arms of the first and second safety devices, and means connecting the governor rope to the actuating arm of one of the safety devices.

7. The lift apparatus of claim 1, including a mounting base, and means fixing the cam and back-up plate to the mounting base.

Claims

1. Lift apparatus comprising: a structure including first and second spaced guide rails, each of said guide rails having first and second opposed side guide surfaces, and first and second safety devices carried by a platform which operative on said first and second guide rails, respectively, each of said safety devices including a back-up plate, and a cam member having a circular portion, said back-up plate and cam member being disposed adjacent to but spaced from the first and second side guide surfaces, respectively, of a guide rail, an actuating arm, means pivotally mounting said actuating arm coaxial with the circular portion of said cam member, and a roller carried by said actuating arm, said actuating arm, when pivoted about a predetermined angle, directing said roller about the circular portion of said cam member into engagement with the second side guide surface of its associated guide rail, said actuating arm and roller having a predetermined clearance between their engaging surfaces selected to enable the actuating arm to position the roller against the guide rail while being isolated from forces generated between the engaging cam member, roller, guide rail and back-up plate.