tke 3 february2007art

February 2007 | ELEVATOR WORLD | 59

Continuing Education: Rope Gripper

Installation and Adjustment of the Hollister-Whitney Rope GripperTM

by Walt Glaser

HistoryThe Rope Gripper from Hollister-

Whitney is a commonly used emer-gency brake for geared traction ele-vators in North America. There aretens of thousands already installedand working, with thousands moreinstalled every year. Elevator mechan-ics need to understand this importantsafety device – how it is installed, howit works and how to make sure itkeeps working properly.

The Rope Gripper was developedby Hollister-Whitney and its sistercompany GAL Manufacturing in thelate 1980s. A series of elevator acci-dents pointed out the need for abackup device to be deployed if thedriving machine of a traction eleva-tor became somehow disengaged fromthe machine brake. In these cases, be-cause the counterweight is often heav-ier than the car, the elevator wouldoften move up. Hollister-Whitneywas quick to recognize this poten-tially dangerous situation and developthe proper device to prevent it.

Learning ObjectivesAfter reading this article, youshould have learned about u the history of and code require-

ments for elevator emergencybrakes.

u the principle behind the RopeGripperTM emergency brake.

u the components and basic operation of the Rope Gripper.

u proper mounting of the brakeunit and pump unit.

u Rope Gripper control circuits.u testing and inspection proce-

dures for the Rope Gripper.

Code RequirementsIn 1990, the CSA B44 standard

was the first to codify a requirementfor an elevator emergency brakesuch as the Rope Gripper. This cameafter a directive was issued in 1988in the province of Ontario, whereseveral accidents had occurred. In2000, the ASME A17.1 code (nowharmonized with B44) added theemergency-brake requirements. Theseare contained in the current ASMEA17.1 and CSA B44 codes in section2.19, and provide an extra measureof protection against two potentiallylife-threatening situations.

Although there are many require-ments that an elevator emergencybrake must conform to, its primarypurpose is to protect against 1) as-cending car overspeed and 2) unin-tended car movement with doorsopen. The applicable code rules forthese are found in ASME A17.1/CSAB44 sections 2.19.1 and 2.19.2, re-spectively. This article will delvedeeper into the code requirements inlater sections.Why a Rope Brake?

There are other elevator emer-gency brakes, but the rope brake iseffective and widely accepted.

Sheave Brakes – devices to arrestthe rotation of the driving sheavehave been available as emergencybrakes. The major drawbacks ofthese designs are that they are veryhard on other machine components(specifically the sheave itself), andthere is the potential to stop thesheave without stopping an ascend-ing car (i.e., given enough momentum,the ropes could slip traction whenthe drive sheave is suddenly stopped).

This article is part of ELEVATOR WORLD’s

Continuing Education program. Elevator-industry

personnel required to obtain continuing-education

credits can receive one hour of credit by reading

the article and completing the assessment exami-

nation questions found on page 111.

For this article and more continuing-education

opportunities, visit www.elevatorbooks.com

Value: 1 contact hour

Continued

EDUCATION PROGRAM

CERTIFIEDELEVATOR TECHNICIAN

NATIONAL ASSOCIATION OF ELEVATOR CONTRACTORS

®

Approved by NAEC for CET

Approved by NAESA for QEI

60 | WWW.ELEVATOR WORLD | February 2007

Continuing Education: Rope Gripper Continued

Bidirectional Safeties – These de-vices work a lot like traditional downdirectional safeties, but are capableof deploying – grabbing the rails tostop the car – in both directions.Bidirectional safeties can be effectivein protecting against ascending caroverspeed, as they can be set using atraditional centrifugal governor. Pro-tection against unintended car motionis a little more difficult to accomplishwith bidirectional safeties. However,some newer designs do.

A rope brake can safely, quickly,effectively, repeatedly and economi-cally protect against both situationswithout any damage to equipment.Barring catastrophic rope failure, inwhich case safeties will set, there isno potential to stop the ropes with-out stopping the car.Rope Gripper Overview

Rope Gripper consists of two com-ponents: a pump unit and a brakeunit (See Figure 1).

The pump unit consists of apump, valve and control circuits thatare used to open the brake unit andtrigger its activation. The pump com-presses the springs and opens themovable shoe on the brake unit toaccommodate the elevator ropes andput the Rope Gripper into the “ready”(“running”) position.

The brake unit is the device thatactually clamps the elevator ropes tostop elevator movement. It uses acombination of a hydraulic cylinderand springs to push a rotating shaftup a stationary power cam, whichapplies pressure to the elevatorropes. The brake unit also has a so-lenoid assembly that is used to holdthe movable shoe in the “ready” (open)position, and it applies the movableshoe when a fault signal is receivedfrom the elevator controller.

The Rope Gripper is opened hy-draulically (with a pump and valve)but held open electrically. It is trig-gered by the loss of electricity (of thesolenoid assembly) and activatedmechanically by way of springs, rotating shaft and power cam. Figure 1


The Rope Gripper activation signalscome from the elevator control. It is theresponsibility of the control manufac-turer to provide the proper and nec-essary circuitry to operate this devicein a manner that is code compliant.Understanding Basic Operation

The Rope Gripper comes pre-adjusted from the factory. It is unlikelythat a mechanic will need to adjust itin the field. Still, a mechanic needsto understand how it operates andhow to make sure it is functioningproperly.

The most common mistake wesee with Rope Gripper setup relatesto a basic misunderstanding. The RopeGripper uses hydraulics (a pump) toopen it into the “ready” (“loaded”)position, but it is held open electri-cally. Once a Rope Gripper reachesthe proper open position, the Brake-Ready micro-switch contact will openand turn off the pump. The pumpshould run just long enough to getthe latch hook past the trigger, andthen it should shut off. The hydraulicpressure will slowly bleed off untilthe trigger and latch are resting to-gether. At this point, the trigger andlatch are engaged and the hydraulicportions could be disconnected withno effect. If/when the hydraulicpressure is improperly used to holdthe Rope Gripper open, it quickly re-sults in leaky seals and/or brokencylinders.

When properly adjusted, the Brake-Ready micro switch will turn off thepump when the trigger and latch areengaged, and while there is still ap-proximately a 1/32-inch clearancebetween the rotating cam and thebottom of the cam slot.

Anytime the Rope Gripper pumpsthe movable shoe into the open po-sition, the mechanic needs to lookfor two things:1) The solenoid assembly latches –

electricity to the solenoid plungeris designed to hold the shoes open(Figures 2 and 3).

Figure 2

Figure 3

Continued


Figure 5

Figure 4


2) The Brake Ready micro switchturns off the pump (Figure 4).The Rope Gripper is triggered and

will grip the ropes when a fault is de-tected or when there is loss of power(Suggested Control Circuits section).There is a manual mode available forthe pump unit so that during a pro-longed power outage, the Rope Gripperbrake unit can be manually openedto facilitate releasing any trappedpassengers. When placed in themanual mode, power is removed fromthe machine or elevator brake.Proper Mounting

A mechanic needs to understandthe tremendous forces that will beexerted on the Rope Gripper brakeunit. By code (ASME A17.1/CSA B44section 2.19.4), the supports for theRope Gripper must be able to with-stand the same forces and stressesas the machine, machine beams andbed plates. This is a crucial issue.(See Figure 5 for several typicalmounting configurations for thebrake unit.) If you don’t have com-plete structural/stress analysis, agood rule of thumb is to use thesame support for the Rope Gripperbrake unit that is used for the ma-chine, i.e., if the machine is suppliedon 6-inch I-beams, mount the RopeGripper brake unit on 6-inch I-beams.If the machine is through-bolted on afloor plate, do the same for the RopeGripper brake unit.

Note that the overspeed protec-tion from the emergency brake is onlyrequired by code in the up direction.This being said, most of the time it isconsidered desirable to trigger theRope Gripper if overspeed is detectedin either direction. When consideringmounting configurations, under-stand that extreme forces will be ap-plied in both directions.

Due to space constraints, you mayneed to get inventive with themounting of the brake unit. On somegearless machines or basement trac-tion sets, the mounting of the brakeunit will be a challenge. Hanging the

Figure 6

Figure 7


brake unit upside down from the un-derside of the machine-room floor isan option. Sometimes, the brake unitwinds up being horizontal betweentwo sheaves on a basement machine.For a special application, you maywant to contact Hollister-Whitney.Mounting the Brake Unit

Make sure that security set screwsare in place and holding the rotatingshaft in the “ready” position (movableshoe open) as shown in Figure 6.Brake units are shipped this way.

Remove the four snap rings andthe two connecting arms shown inFigure 7.

Remove the movable shoe assem-bly. Place the brake unit into positionon its mounting structure and, withthe angle bolts loosened, align thebrake unit so that the ropes are incontact with the stationary shoe lin-ing from top to bottom and centeredside to side. It is important that theropes barely touch the stationaryshoe lining, and that the contact

Continued

eheinrichs

Text Box

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Text Box


is even over the entire contact area.Misalignment can cause unevenand/or excessive lining wear.

Securely tighten the mountingbolts and the angle bolts.

Double check alignment after thebrake unit is tightened into final po-sition. Readjust if necessary.

Replace the movable shoe assembly,making certain that the chamfered cor-ners of the connecting arms face in(toward the brake unit) and replace the

connecting arms and their snap rings.Make sure that the snap rings seatproperly into the groove on the shaft.Mounting the Pump Unit

Mounting the pump unit is mucheasier – only two requirements: 1) itneeds to be fixed in place, right-sideup, and 2) it needs to be within hosereach of the brake unit. Extra hoselength can be obtained if necessary.

It is important to remove theshipping cap on the top of the

pump unit and insert the dipstickstrapped to the inside of the pump-unit enclosure. DO NOT OPERATETHE ROPE GRIPPER UNTIL THESHIPPING CAP HAS BEEN RE-MOVED. Check the oil level – oilshould be at least 1 inch up onthe dipstick.Suggested Control Circuits

The Rope Gripper is a dumb device.Its function is a result of signals fromthe elevator control. (See attached sug-gested circuits for the control of theRope Gripper in Figure 8.) Any timethe Rope Gripper is activated, poweris removed from the elevator machineand brake.

The Rope Gripper is designed sothat it can and will automaticallyreset if it is triggered due to simpleloss of power. On resumption ofpower, the pump unit will start andreturn the brake unit to the open andready position.

By code, when the Rope Grippersets due to a detected fault (over-speed or unintended motion withdoors open), it must be manuallyreset. A mechanic must correctthe fault before the Rope Gripperis reset and be sure he knowswhat the elevator is going to dowhen the ropes are released. If afault has been detected, there isvery likely some sort of failure ofthe machine brake. Very often,the Rope Gripper is the only thingkeeping the car from moving. Ifthe Rope Gripper is reset with-out correcting the problem thatcaused the fault, it is very likelythat the car will take off – mostlikely in the up direction. This isa potentially dangerous situation.A mechanic needs to understandthis and be prepared to react.Test and Lining Wear-in

Check for proper trigger and latchsetup (Figures 2 and 3). Starting withthe Rope Gripper held open with thesecurity screws (like it was shipped),do the following:

Figure 8

Must be made when doors are opened in door zone

Must be made outside of door zone

Suggested Control Circuits

Governor overspeed switch (GOS)

GRC1

GRC2

DZC1

DZC2

RG1

RG2

DZ1

DZ2

Other circuits Ground

Ground

RG1 RG2

DZ1 DZ2

RG1 RG2

RG1 RG2

DZ1 DZ2

6 amps

Gripperpower supply

120 VAC power supply



Figure 9

u Flip the off/on switch to the onposition. The latch should engagethe trigger mechanism and elec-trically hold the movable shoe inthe open (ready) position. If thesolenoid does not activate, checkthe controller wiring.

u After the solenoid has activated,remove the security set screws. Ifthe connecting arms move up thecam when the security set screwsare removed, the latch did nothold, and it will be necessary tomanually return the brake unit tothe ready position. To do this,place the valve in the Pump Unitinto the manual mode (Figure 9)and use the hand pump to reopenthe brake unit. If the wiring hasbeen corrected, when it reachesthe ready position, the solenoidwill activate and the latch willhold the brake unit in the readyposition.

u Security set screws must be com-pletely removed in order to operatethe Rope Gripper. Store them insidethe pump unit. Security set screwsshould always be in place whenperforming maintenance on orworking on an opened Rope Gripper.

Basic Function Testu Check to make sure that while the

valve is in the manual mode, themanual-mode micro switch con-tact is open and the car is pre-vented from running.

u Check to make sure that with thevalve in the automatic position andthe off/on switch in the on position,the Rope Gripper is in the “ready”position (not clamping the ropes).

u Move the off/on switch into theoff position. This should: 1) acti-vate the Rope Gripper and clampthe ropes and 2) open the contactson the “elevator can run” microswitch, which removes powerfrom the elevator motor and ma-chine brake. Continued

Lining Wear-inIdeally, when linings are properly

worn in, you should see: 1) there isapproximately a 1/16-inch groovedepth in the lining of both the sta-tionary and movable shoe liningsand 2) the rotating shaft and con-necting arms should have movedaround the bottom corner of thepower cam and stopped approxi-mately 1/2 inch up the cam.u Run the car in the slow speed from

top to bottom and wipe down theropes – remove dirt, oil and grease.

u Jump terminals RG5 to RG6 – thiswill close the gripper on the ropesbut still allow the car to run.

u With the off/on switch in the offposition, run the car slowly upand/or down. The Rope Gripperwill exert light pressure on theropes, and the linings will begin towear in. As linings wear, the rotat-ing shaft will begin to move in itsslot, and will turn the corner andbegin to move up the power cam.

u For Models 620, 622, 624 and 625– Once the rotating shaft hasturned the corner on the powercam, stop the car and remove thejumpers from RG5 and RG6. Theconnecting arms (rotating shaft



ends) should have moved upwardapproximately 1/2 inch duringlining wear-in.

u For Model 626 – To be effective,the groove depth needs to be about1/16-inch deep. Sometimes youcan make several trips with the carwhile setting the Rope Gripper andget a groove depth of about 1/16inch, though the rotating shaft hasstill not made the turn and startedup the power cam. If this happens,once you have sufficient groovedepth, remove the jumpers fromRG5 and RG6 and then remove theshim (lining-wear spacers) frombetween the shaft support blockand movable shoe (Figure 7). NOTE:Anytime it is necessary to work ona Rope Gripper in the open posi-tion, a mechanic must first rein-stall the security set screws. Hav-ing removed this shim, the rotatingshaft should have moved approxi-mately 1/2 inch up the power cam.

Adjusting for Lining WearLinings are 1/4-inch thick when

new. Linings must be replacedwhen the groove depth reaches3/16 inch (1/16-inch wear re-maining on each pad). (See nextsection, Replacing Brake Linings.)

As the linings wear, the rotatingshaft will continue to move furtherup the power cam. Near its travellimit, it will open the contact in the“excessive wear” micro switch (Figure4) and the Rope Gripper will not au-tomatically reset. If this occurs be-fore the groove depth is 3/16 inch,you can adjust the gripper to put itback in service. To do this:u With the off/on switch in the off

position, set the valve for manualoperation (Figure 9) and pump thebrake unit into the ready position.

u Install the security set screws (Fig-ure 6) so that they are holding therotating shaft in position.

u Remove the lining-wear spacerfrom behind the shaft support blockon the movable shoe assembly andreinstall the spacer between theshaft support block and the mov-able shoe itself (Figure 4).

u Set the valve back into the auto-matic mode (Figure 9).

u Put the off/on switch in the on po-sition.

u Remove the security set screws(Figure 6).

u Confirm that the rotating shaft willmake the turn and travel approxi-mately 1/2 inch up the power cam.

Replacing Brake Liningsu With the off/on switch in the off

position, set the valve for manualoperation (Figure 9) and pump thebrake unit into the ready position.

u Install the security set screws sothat they are holding the rotatingshaft in position (Figure 6).

u Remove old brake-lining assem-blies by loosening the liningmounting screws (Figure 10).

u Install new brake linings and re-place their mounting screws.

u Set the valve back into automaticmode (Figure 9).

u Put the off/on switch in the on po-sition.

u Remove the security set screws.u Follow the procedure found ear-

lier under “Lining Wear-in.”u Confirm that the rotating shaft will

make the turn and travel approxi-mately 1/2 inch up the power cam.

Figure 10


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Hollister-Whitney Rope Gripper

Figure 11

Test & Inspection Figures 11 and 12 are test and in-

spection check sheets for Rope Gripper installations. Assuming thatthe mounting was done properly, fol-lowing the check sheet will ensurethat your installation is workingproperly and is code compliant.

Walter Glaser, executive vice president of GAL

Manufacturing, vice president of Hollister Whitney

Elevator Corp. and president of Elevator Compo-

nents Industries Inc. of Canada, is active in the

everyday affairs of all three companies. With a

background in electrical and mechanical engineer-

ing, Glaser has been involved in many product

designs. His electrical designs include elevator

control systems, door-operator control systems

and a disc-brake monitor. Glaser’s mechanical

designs include elevator disc brakes, governors,

safeties and other devices. With 45 years of expe-

rience in the elevator industry, Glaser holds several

U.S., Canadian and British patents, authors frequent

technical articles in the industry and is generally

recognized as the inventor of the Rope Gripper.Continued



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Hollister-Whitney Rope Gripper

Figure 12

Learning-Reinforcement QuestionsUse the below learning-reinforcement questions to study for the Continuing Education Assessment Exam available online at www.elevatorbooks.com or on page 111 of this issue.

u What are the two primary things an elevator emergency brake must protect against? u How does the Rope Gripper differ from sheave brakes and bidirectional safeties? u What are the components of the Rope Gripper and how are they installed? u When is a manual reset required with the Rope Gripper? u How is the Rope Gripper tested and adjusted?

1. Elevator emergency brakes are required to protectagainst:a. Failure of the traditional safety.b. Unintended motion and ascending car overspeed.c. Catastrophic rope failure.d. Overweighted elevator cars.

2. The Rope Gripper has been used as an elevator emer-gency brake since the:a. Late 1960s.b. Late 1970s.c. Late 1980s.d. Late 1990s.

3. The Rope Gripper consists of:a. A brake and a solenoid unit.b. A safety and a pump unit.c. A brake and a pump unit.d. A governor and a brake unit.

4. The Roper Gripper is opened and put into the readystate using:a. A hydraulic pump.b. Electricity.c. Springs and cams.d. All of the above.

5. The Rope Gripper is held in the open and ready posi-tion using:a. A manual check valve.b. Electricity and a solenoid.c. Springs and cams.d. All of the above.

6. The signal to activate the Rope Gripper comes from:a. Control circuits on the pump unit.b. The elevator control.c. The “elevator can run” micro switch on the brake

unit.d. A solenoid on the pump unit.

7. Manual reset of the Rope Gripper is required when it isactivated due to:a. Unintended motion with doors open.b. Loss of power.c. Up direction overspeed.d. A and B.e. A and C.

8. Shoes must be replaced when the groove depthreaches:a. 1/2 inch.b. 3/16 inch.c. 1/16 inch.d. 3/8 inch.

9. Security screws for the Rope Gripper:a. Hold the Rope Gripper in the open position.b. Provide extra backup for Rope Gripper operation.c. Fasten the Rope Gripper to its mounting structure.d. Must be in place during normal operation.

10. The brake unit on the Rope Gripper must be mounted:a. So that it can withstand the same stresses as the

machine.b. With the ropes touching the stationary shoe.c. Within hose reach of the pump unit.d. All of the above.

11. When the test switch is turned to the “off” position, theRope Gripper should:a. Activate and clamp the ropes.b. Remove power from the driving machine and brake.c. Electrically release the solenoid.d. All of the above.

ELEVATOR WORLD Continuing EducationAssessment Examination Questions

Instructions: u Read the article “Installation and Adjustment of the Hollister-Whitney

Rope Gripper” (page 59) and study the learning-reinforcement questions. u To receive one hour of continuing-education credit, answer the assessment

examination questions found below online at www.elevatorbooks.com or fillout the ELEVATOR WORLD Continuing Education Reporting Form found over-leaf and submit by mail with payment.

u Approved for Continuing Education by NAEC for CET.


Continuing Education: Rope Gripper

tke 3 february2007art

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