US2719608A

US2719608A - Elevator counterweight guide clamp safety

Info

Publication number: US2719608A
Application number: US321660A
Authority: US
Inventors: Callaway Lillian
Original assignee: WATSON ELEVATOR Co Inc
Current assignee: WATSON ELEVATOR Co Inc; WATSON ELEVATOR COMPANY Inc
Priority date: 1952-11-20
Filing date: 1952-11-20
Publication date: 1955-10-04
Anticipated expiration: 1972-10-04

Description

Oct. 4, 1955 c. R. CALLAWAY ELEVATOR COUNTERWEIGHT GUIDE CLAMP SAFETY 5 Sheets-Sheet l Filed Nov. 20, 1952 w K r as w TA N m P m m N o T 7 lv w L4,,

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Oct. 4, 1955 c. R. CALLAWAY ELEVATOR COUNTERWEIGHT GUIDE CLAMP SAFETY 5 Sheets-Sheei 2 Fiigd Nov. 20, 1952 emx m EI

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Q? INVENTORF f C LARENCE. R. CALLAWAy. omusgv By Lmmw CALLAWAYI ExEeu-rmx By HT'TOENEY /riL Oct. 4, 1955 c. R. CALLAWAY ELEVATOR COUNTERWEIGHT GUIDE CLAMP SAFETY 5 Sheets-Sheet 3 Filed Nov. 20, 1952 INVENTOR. CLARNCE R. CALLAWAY, Dscnszo By L.\L\-IAN CALLAWAY. Exicp-rfilx HTTOEA/EV 4, 1955 c. R. CALLAWAY 2,719,608

ELEVATOR COUNTERWEIGHT GUIDE CLAMP SAFETY CLARENCE. R. CALLAWAY, Dscuszu ayLuu/w CALLAWAY, ExEcuTmX M LSQWLW ATTOEA/E) C. R. CALLAWAY ELEVATOR COUNTERWEIGHT GUIDE CLAMP SAFETY Oct. 4, 1955 5 Sheets-Sheet 5 Filed Nov. 20, 1952 INVENTOR.

mm H AQ N ET P u .1 7 WI on MY MM m saw Wu United States Patent Ofiice ELEVATOR COUNTERWEIGHT GUIDE CLAMP SAFETY Clarence R. Caliaway, deceased, late of Fort Myers, Fla.,

by Lillian Callaway, executrix, Fort Myers, Fla., ass'ignor'to Watson Elevator Company, Inc., New York, N. Y., a corporation of New York Application November 20, 1952, Serial No. 321,660 9 Claims. 01. 187-30 This invention relates to elevator counterweight. guide clamp safeties, and more particularly to an improved flexible guide clamp safety for an elevator counterweight.

In copending application .of Clarence R. Callaway, Serial No. 313551, filed October 7,jl9 52,there is shown an improved elevator car flexible guide clamp safety in which the elevatorcar is brought to an emergency stop by applying braking action upon the guide rails in the event the elevator exceeds a predetermind sped of downward movement. This prevents an elevator from dropping if the cables suspending the elevator should part for any reason.

Elevator cars are fitted with counterweights to balance the weight of the car. If the counterweight suspension cable should part by accidental means, the counterweight would 'be allowed to drop. Frequently elevators are installed in tall buildings such that the elevator shaft is located above an occupied space or area. Unless some means .are provided for braking .free descent of acounterweight there exists serious danger that the counterweight will crash through .the .bottom of the elevator shaft into the occupied area and cause damage to lifeand property.

The flexible guide clamp safety, as shown .in said .620- pending application of Clarence R. Callaway, is-too bulky for installation as a safety for a counterweight which usually occupies a-restricted cross-sectional area.

Safety devices for stopping counterweights in event of their excessive downward speed :are known to .the .art.

These :devices usually take the form of .a spring=actuated brake adapted to clamp the guide rails which serve to guide the counterweight. If the clamping pressure exercised by the spring is'too weak, the counterweight will not be brought toastop; If the clamping pressure .is too great, the clamp may seize the guide rails, .and .if-the energy .is sufiiciently great, .carrythem away with attendantdamage to apparatusand injury to persons.

One object of this invention is to provide aflexible guide clamp safety for counterweights for elevatorcars in :which heavy spring pressure maybe employed and yet insure that the icounterweight brought to -a-stop;in sucha gradiual manner as to avoid injury either-topersons or property. I

Another .object iofithis invention ,is to .provide la flexible guide :clamp safety for eounterweights whichimay The :installed'withina reduced cross-sectional area.

A furtherobject of this'invention .isto provide a=flexi- Figure 2.

Patented Oct. 4, 1955 A further object of this invention is to provide a counterwei ght flexible guide clamp safety 'having clamping jaws which will align themselves correctly with the guide rails at all 'times independent of imperfections in the guide rails. In general this inv'ention contemplates the provision of a pair of jaw -levers biased to a fixed position by a stout spring. The spring acts against the stop and there 'isnorma'lly -no pressure against the clamping jaws. Adjacent the guide -r'ails there 'is positioned a pair of wedgeshaped clamping jaws adapted to be moved into engagernent with the guide rails when it is desired to brake the counterweight. Between 'eac'h pair comprising one of the jaw levers and one-ofthe wedge-shaped jaws there is provided aplurality of balls disposed in a'ball carrier. Means tofpos'ition the ball carrier correctly with respect to the jaws in all positions is provided. The wedging action between the guide rails and the jaw levers tends to cam the ends of the jaw levers inwardly, that is, toward each other. This motion will cam a thrust-transmitting 'carn member-against the action of the spring, the thrust being transmitted through the balls. The arrangement is such that when the clamping jaws have reached their limit of motion a constant retarding force will be exercised upon thegu'id'e rails by the springswh'ich bias the cams which earn the jaw levers. The balls will insure that the wedgeshaped clamping jawsalways align themselves properly with the surfaces of the guide rails since the thrust is being transmitted through spherical surfaces.

In the accompanyingdrawings which form part of the instant specification and which are to be read in conjunction therewith and in-whichlike reference numerals are used to indicate like parts in the'various views:

Figure 1 is "an elevation of a counterweight mounted Lon a pair of'guide rails equipped with a 'flex'ible guide show the construction.

Figure '3 is a side 'elevation'ta'ken along the line 3-3 of Figure '4 is a sectional view drawn on'an'enlariged" scale taken along the line 4+4 of Figure 2.

Figure 5 is-a sectional view drawn'on an enlarged'scale taken along the line 5-5 of'Figure 2.

Figure '6 is-a sectional vie Figure 7 is a sectional perspective view viewed generally along the line 7 7 of Figure 2 with partsbroken away and parts in section. I

, 'Figure8 is a sectional view drawn on an enlarged scale taken along the line"8-"8 of Figure 1.

More particularly, referring now 'to the drawings, the counterweight indicated generally by the reference numeral 10 is suspended from ca'bles12 secured to a coun- 'terweight frame 14 by means of 'a bracket 16. The

Me guide clamp safety :for elevator connterweights by a frame 22 Whlch 18 secured to the bottomof which a constant retarding :force will be appliedeven though the counterweight is traveling at high speed.

Another object ofthis invention is to provide axflexible guideclamp safety forcounterweights-which insures -the alignmentof the 'clamping jaws with the guide rails at all times.

to'a sudden'stopw'ith its attendant danger.

counterweight frame 14 is positioned between a pair of guide rails 18 having a generally T-shaped cross-sectional "area. The counterweight frame 14 carries a plurality of weights 20. This guide clamp'safety-assembly 'is carried iwhich is governed by a governing device asis Well-known to the art. A tail rope 26 is attached to the governor rope by a-friction clamp (not shown). The arrangement is such that if the t counterweight moves downwardly at a speed in excess of that to which the governor is set,

there will 'bel-a tug #upon-the tail rope 26 in the direction drawn'on an enlarged scale takenalong the line 66 of Figure 2. i

of the arrows shown in Figure 1. The end of the tail rope 26 is secured to an arm 30 which is carried by a crank plate 32. This plate is pivotally mounted about a shaft 34 carried. by the counterweight-frame 14. A lever 36 is pivotally carried by the frame 14 about shaft 38. An adjustable link 40 connects one 'end of crank plate 32 to one end of the lever 36. The other end of lever 36 is connected by link 42 to a shiftable member 44 formed in the shape of a U having a pair of

arms

54 and 56. As can be seen by referenceto Figure 8,-the arm 54 of the member 44 carries a flange 48. and the arm 56 of the member 44 carries a flange 46. These flanges are positioned in a pair of

guideways

50 and 52 carried by the counterweight frame 14.

The frame 14 carries a bell crank 58 pivoted about a shaft 60. An adjustable link 62 connects the crank plate 32 with the bell crank 58 and a right-hand link 42 is connected to a right-hand shiftable member 44 identical in construction to that shown in Figure 8 for the left-hand shiftable member 44.

When there is a tug upon the tail rope 26, the right-hand end of arm 30 will be pulled upwardly, rotating the crank plate 32 in a counterclockwise direction, as viewed in Figure 1. This will rotate the lever 36 in a clockwise direction and the bell crank 58 in a counterclockwise direction. The clockwise rotation of the lever 36 will pull the left-hand link 42 upwardly and the counterclockwise rotation of the bell crank 58 will pull the right-hand link 42 upwardly. Thus, an upward pull of the tail rope 26 will pull both shiftable members 44 upwardly.

The lower portion of arm 54 of each shiftable member 44 carries a link 70 pivoted thereto by a pin 72. Pivoted to each arm 56 by pin 74, a link 76 is provided. The lower ends of these links'are attached to the clamping jaws which will be described more fully hereinafter.

Referring now to Figures 2 and 3, the guide clamp safety frame 22 carries a pair of vertically positioned pins 80 around which are pivotally mounted a pair of clamping

levers

82 and 84, there being one pair of clamping levers for each of the pins 80. Since the construction is symmetrical for both guide rails 18, the construction with reference to one of the clamping lever assemblies will be described. The lever 84 is formed with a lever jaw 86 which is disposed to one side of the flange 17 of the guide rail 18 and spaced therefrom, as can readily be seen by reference to Figure 2. The lever 82 is provided with a lever jaw 88 which is disposedon the opposite side of the flange 17 symmetrical with the lever jaw 86. Each

lever

82 and 84 is bifurcated, as can readily be seen by reference to Figure 3. A disk 90 is positioned within the area formed by the lever arms. The disk carries a shaft 92 around which stout helical spring 94 is positioned. One end of the spring rests against the disk 90. A second disk 96 is provided with an aperture so that it may pass over the shaft 92 to a position against the other end of the spring 94, as can readily be seen by reference to Figure 3. Secured to the disk 96 by bolts 98, a cam 100 is provided. This cam is adapted to coact with the lower bifurcations of the

levers

82 and 84, as will be pointed out more fully hereinafter. Similarly secured to the disk 96 by bolts 102, an upper earn 104 for coaction with the upper bifurcations of the

levers

82 and 84 is provided. The inner end of lever 82 carries a pair of rollers 106 adapted to rotate about pins 108. One of the rollers is positioned on the upper bifurcation of lever 82, and the other of the rollers is positioned on the lower bifurcation of lever 82. Similarly, the inner end of lever 84 carries a pair of rollers 110 mounted for rotation about pins 112. One of the rollers 110 is carried by the upper bifurcation of lever 84 and the other of the rollers 110 is carried by the lower bifurcation of lever 84. A plurality of spacer disks 114 are positionedbetween the

cam members

100 and 104 and the disk 96 in order to enable the cams 184 and to be correctly positioned with a proper compression of spring 94. The

position of the cams is controlled by the nut 116 which is mounted on the threaded end of shaft 92. The disk 96, the spacer members 114 and the cams and 104 are adapted to slide as a unit upon the shaft 92. Securing the nut 116 upon the shaft compresses the spring and at the same time moves the cams to the right, as viewed in Figures 2 and 3, against the action of the right-hand spring 94. This will permit the inner ends of the

levers

84 and 82 to move inwardly, that is, toward the transverse center line of the assembly. It will be observed that each of the

cams

100 and 104 is provided with a pair of cam surfaces 118 and 120. The cam surfaces 120 are adapted to coact with rollers 106, while the cam surfaces 118 are adapted to coact with rollers 110. If the nut 116 is unscrewed on shaft 92 the spring 94 moves the cams to the left, as viewed in Figures 2 and 3, camming the inner ends of the

levers

82 and 84 outwardly, thus bringing the

lever jaws

88 and 86 more closely adjacent the flange 17. Since the nut 116 limits the action of the spring 94, the inner ends of the

levers

82 and 84 will be free to move outwardly. A pair of stop members are provided to prevent this. A stop member 122 is adapted to limit the outward position of the inner end of lever 84. The stop member 124 is adapted to limit the outward position of the inner end of lever 82.

It will also be observed that the

lever jaws

86 and 88 cannot be moved away from the flange 17 without moving the inner ends of the

levers

82 and 84 inwardly. Such inward motion would cause the rollers 106 and 110, acting through the cam surfaces 120 and 118, to move the disc 96 to the right against the action of spring 94. In this manner, the

jaws

88 and 86 are spring loaded to take an outward thrust by a very compact spring arrangement occupying a comparatively small cross-sectional area. It will also be observed that due to the fact that the length of the lever arm of each lever from its pivot pin 80 to the end of the lever jaw is short with respect to the length of the lever arm from the pivot pin 80 to the roller pins which carry the rollers. In this manner the force of spring 94 is greatlymultiplied so that a'comparatively small spring will exercise a large thrust. The mechanical advantage of the levers can also bemultiplied by the correct angle of the cam surfaces 118 and 120. If the inclined surfaces extend 45 with respect to a vertical plane passing through the roller pins, no mechanical advantage is obtained. By disposing the cam surfaces at, a more obtuse angle than/15 with this plane the mechanical advantage of the spring is increased, as will be well'understood by those skilled in the art.

Referring now to Figure 4, the frame 22 below the lever and spring assembly carries a stub shaft on one side of the flange 17 and a stub shaft 132 on the other side of flange 17; A bracket 134 is provided with two downwardly directed

flanges

136 and 138. The flange 136 is provided with a pin 138' around which a lever 140 is pivoted. Similarly, the flange 138 is provided with a pin 142 around which a lever 144 is pivoted. A link 146 is pivotally secured by pin 148 to the end of lever 144. The other end of link 146 is pivotally connected to a wedge-shaped clamping jaw 1S0 disposed on one side of the flange 17. A second clamping jaw 152 is disposed on the other side of the flange 17. This clamping jaw is connected by link 154 to the end of lever 140 by means of'pin 156. The clamping jaw is connected at its upper end to the link 76 and is supported thereby. The clamping jaw 152 is connected to the lower end of link 70 and is supported thereby. The stub shaft 130 pivotally supportsa lever by pin to the other end of lever 144. The other end of lever 158 is connected by pin 162 to a link 164 which supports a ball carrier 166 which is disposed between the leverv jaw 88 and'the clamping jaw 150. The ball carrier supports a'plurality of balls 168 through which thrust is adapted to be transmitted from the clamping jaw to the lever jaw. In a similar manner a lever170 is pivoted 158. One end of this lever is connected empress about stub shaft 132. neiend'of this -'l ever is connected by pin 172 to a link 174 which isconr'rected to and supports a ball carrier 176%provided-with -balls 178, The other end of lever 170 istzorrnectedfby pin 171*itio the otherendoflever140. (I w The construction can more clearly be seen by refer-- ence to Figure 7. It will bezobservedthat the length'of the lever arm from stub shaft 130 to pinaifll is twice :the length of the lever arm from "stub shaft 130 10 :pin 162. The linkage is actuated, as pointed :out ab'ove, by the upward motion of the member whichzmoves link76 upwardly, thus moving the wedge shap'edlclamping Ejaw 150 upwardly. This motion'rotates-the lev'er 144. Since the end of lever i144 is connected'lto the end ;of. lever'1'58 by pin 160, the lever 158 will'irotatesin the same .direc- I tion as lever 14'4. 'Theupward'rnotiomof link 164, however, will be through half the amplitude of the upward motion of link 148 due to the 'iconstruetiomof the linkage. It will be observed that theclarnpingzjaw 150 in the unclamped position shown in Figure 7 has its upper end about the midpoint of the 'le'ver'ja'w 88. -It will also be observed that the upper portion of the ball carrier 166 is disposed about half way between the top of the clamping jaw and the top of the'l'everjawffwhen the parts 'are in clamping position, itis advantageoust hat the "leverj'aw, the ball carrier and the wedge-shaped clamping jaw have their midpoints in substantial alignment. To accomplish this, the ball carrier must travel through half the amplitude of the travel of the wedge-shaped clamping jaw. The linkage which has just been described accomplishes this. When the

links

70 and 76 pull the wedge-shaped

clamping jaws

150 and 152 upwardly half the distance traveled by the clamping jaws will be traversed by the ball carriers. The construction just described maintains the parts in their proper relationship and precludes sliding displacement of the ball carrier so that the thrust will be transmitted through all of the balls when the flexible guide clamp safety is in the clamping position.

In operation, when the elevator counterweight descends at a speed in excess of that determined by the governor rope 24, the tug upon the tail rope will lift the arm 30 and rotate the crank plate 32 in a counterclockwise direction. This will rotate the lever 36 in a clockwise direction and the bell crank 58 in a counterclockwise direction, thus lifting the members 44 through the links 42. This will lift both wedge-shaped

clamping jaws

150 and 152 upwardly through

links

76 and 70. The upward motion of the clamping

jaws

150 and 152 will lift the

ball carriers

166 and 176 upwardly together with their

balls

168 and 178 through half the distance which the clamping jaws travel, thus bringing the clamping jaws and the ball carriers in horizontal alignment with the

lever jaws

86 and 88. Due to the wedge-shaped configuration of both the lever jaws and the clamping jaws the clamping jaws will be cammed inwardly to grip the lateral surfaces of the flange 17 of the guide rail 18. This, of course, will occur at both sides of the counterweight. In this motion the ends of the lever jaws will be moved outwardly, that is, away from each other. This motion will bring the inner ends of the lever jaws toward each other. Since the rollers 106 and 110, carried by the lever jaws, are in engagement with the

inclined surfaces

120 and 118 of the

cams

104 and 100, the inward motion of the inner ends of the

levers

82 and 84 can take place only by camming the cam members and their supporting disk 96 outwardly from the center of the assembly against the action of the spring 94. Thus the clamping pressure upon the guide rail flanges will be the spring pressure multiplied by the mechanical advantage of the cam and lever transmission. This spring pressure is more than ample to bring the counterweight to a smooth stop. The braking pressure will be substantially constant and there is no danger of gripping the rails or of welding the wedge-shaped clamping blocks to the guide rail flanges. The spherical thrust surfaces afforded by the balls in the ball carriers permit the alignment of the clamping jaws with the guide rail flanges and accommodate for any variations in the orientation of the guide rail flange 'surfaces along the guide rail. In this manner a constant predetermined clamping pressure is applied to provide a constant retarding force which will bring the counterweight to a smooth 'and rapid stop. The spherical bearing surfaces permit the jaws to align themselves at all times. The linkageconstraining the'ba'lllca rr ierto travel at half the speed of the clamping jaws insures the cor- -rect positioning of the ball carriers and the clamping correct positioning of the 'ball carriers with'r'espect to the stationary lever jaws and -:the movable wedge-shaped jaws at all positions. Adequate-mesilient clamping pressureiis provided in a comparatively small cross-sectional area. The clamping pressure can be readily adjusted by the initial compression upon the springs by the use of the spacer plates between the cams and the disk which carries them; All danger of seizing the rail by the clamping jaws and freezing them thereto is eliminated. The clamping jaws can be readily released by moving the arm 30 downwardly, thus pushing the shiftable members 44 downwardly and constraining the clamping jaws to move downwardly away from the clamping position.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the appended claims. It is further obvious that various changes may be made in details within the scope of the claims without departing from the spirit of this invention. It is therefore to be understood that this invention is not to be limited to the specific details shown and described.

This invention ,having been described, what is claimed is:

1. In an elevator counterweight guide clamp safety assembly, a counterweight, a guide rail for the counterweight, a frame carried by the counterweight, a pair of levers carried by the frame pivoted intermediate their ends, a rod carried by the frame extending generally in the same direction as the levers, a cam having a pair of camming surfaces carried by the rod for movement therealong, a spring positioned about the rod having one end thereof abutting the frame and its other end abutting the cam, one of said camming surfaces contacting the inner end of one of the levers and the other of the camming surfaces contacting the inner end of the other of said levers whereby. to cam the inner lever ends outwardly and the outer lever ends inwardly, means carried by the rod for limiting the movement of the cam axially thereof, the outer lever ends being disposed on opposite sides of the guide rail and spaced therefrom, a bearing element carrier positioned between one outer lever end and the guide rail, another bearing element carrier positioned between the other outer lever end and the guide rail, bearing elements carried by the carriers, a clamping ,block positioned between one carrier and the guide rail,

another clamping block positioned between the other carrier and the guide rail, linkages connecting the respective carriers and clamping blocks and means responsive to a predetermined speed of descent of the counterweight for lifting the clamping blocks whereby to clamp the guide rail therebetween, the construction being such that the clamping thrust will move the outer ends of the levers 7 away from each other against the action of the spring.

2. An elevator counterweight guide clamp safety assembly as in claim 1, in which the outer lever ends are formed with surfaces which lie along planes diverging from each other in a downward direction, the bearing elements being adapted to engage said surfaces.

3. An elevator counterweight guide clamp safety assembly as in claim 1, in which the inner lever ends are provided with rollers, said rollers engaging the cannning surfaces.

4. An elevator counterweight guide clamp safety assembly as in claim 1, in which the bearing elements comprise balls.

5. An elevator counterweight guide clamp safety as sembly as in claim 1, in which said clamping blocks are wedge-shaped.

6. An elevator counterweight guide clamp safety assembly as in claim 1, in which each said linkage comprises a first lever pivoted intermediate its ends on said frame, a second lever pivoted intermediate its ends on said frame, means for pivotally connecting one pair of lever ends to each other, means for connecting the other end of the first lever to a clamping block and means for connecting the other end of the second lever to a carrier, the length of the lever arms being such that the carrier will be moved through half the distance that a clamping block is moved.

7. An elevator counterweight guide clamp safety assembly as in claim ,1, in which each of said pair of levers is bifurcated at its inner end.

87 An elevator counterweight guide clamp safety assembly as in claim 1, including means for varying the compression of said spring.

9. An elevator counterweight guide clamp safety assembly as in claim 1, in which said means responsive to a predetermined speed of descent of the counterweight for lifting the clamping blocks includes a tail rope, a lever pivotally carried by the counterweight frame intermediate its ends, means for securing the tail rope to one end of the lever, a second lever pivoted on the counterweight frame intermediate its ends, a link connecting one end of the second lever with the other end of the first lever and links connecting the other end of the second lever with the clamping blocks.

References Cited in the file of this patent UNITED STATES PATENTS