US1727432A

US1727432A - Elevator safety

Info

Publication number: US1727432A
Authority: US
Publication date: 1929-09-10
Anticipated expiration: 1946-09-10

Description

Sept. 10, 1929. F. HYMANS 1,727,432

ELEVATOR SAFETY APPLIANCE Filed Aug. 17. 1926 2 Sheets-Sheet 1 Sept. 10, 1929. F. HYMANS 1,727,432

ELEVATOR SAFETY APPLIANCE Filed Aug. 1']. 1926 2 Sheets-Sheet 2 M H W-M INVENTOR BY A x,

Patented Sept. 10, 1929.

UNITED STATES PATENT OFFICE.

FREDERICK HYMANS, OF YONKERS, NEW YORK, ASSIGINOR TO OTIS ELEVATOR COM- PANY, OF JERSEY CITY, NEW JERSEY, A CQRPORATION OF NEW JERSEY.

ELEVATOR SAFETY APPLIANCE.

Application filed August 17, 1926. Serial No. 129,777.

The invention relates to safety appliances and particularly to safety appliances forelevators.

In elevator operation, it sometimes happens that, owing to faulty operation or' other reason, the elevator car runs past a terminal landing. If th'e caris descending under Such circumstances it may be'brought to rest by a buffer placed in the bottom of the hatchway, in but its counterweight at this time is ascending and this counterweight, bein strained by any force other than its own weight, may run into the overhead work before coming to rest, thus' resulting in damage to the elevator apparatus. If the car is ascending under such circumstances it may strike the overheadwork'causinginjury to the elevator apparatus and possible harm to passengers. This liability of damage is 'aug- 2o mented in high rise elevators, where, with the car passing the upper'terminal landing, there is a long line of descending hoisting ropes pulling down on the counterweight side of the hoisting drum and urging the car upwardly. At this time there is'but a short line of hoisting ropes onv the car side of the hoisting drum and these ropes are moving upwardly. Taking the moving system as a whole, the weight of the counterweight hoist-- ing ropes, their kinetic energy, the kinetic energy of the car and that of the hoisting ropes above the car, constitute factors urging the car upwardly whereas the factors opposing this motion may be merely the weight of the car together with that of the hoisting ropes above the car. Furthermore, in systems where a traction drive is employed, in the event that the elevator motor continues to operate, the tractive effort of the hoisting drum will be transmitted to the hoisting ropes owing to the stress in the hoisting ropes at each side of the drum. This will also tend to cause the car to continue in its upward movement.

The principal object of this invention, therefore, is to prevent under the above circumstances the downwardly moving hoisting ropes from assisting in the movement of the upwardly moving body, whether this body be the car or the counterweight.

One feature of the invention isIthe provision of a safety appliance which operates to grip the hoisting ropes when the counterweight descends below a predetermined point. Another feature of the invention is thepr0 vision of asafty appliance which operatesv apparent from the specification, taken in connection with the accompanying drawings wherein one embodiment of theinvention is illustrated. i 7

In the drawings:

Figure 1 is a schematic representation of a typical elevator system illustrating the adaptation of the safety appliance to both the car and the counterweight;

Figure 2 is a plan view of a rope clamp taken along the line 2-2 of Figure 1;

Figure 3 is a view in partial section taken along line 3,-3.o'f Figure 2; I

Figure 4 is an end view of Figure 3 shown in half section along the-line 44of Figure 3 Figure 5 is 'a wiring diagram illustrating the manner in which the safety appliances may cooperate with an elevator control system, and

Figure 6 is a fragmental representation of an arrangement similar to Figure 1 but with the operating levers at the top of the elevator hatchway.

Referring to Figure 1, the hoisting ropes 3, only one rope being seen in this figure, pass over the hoisting drum 4 and connect the car 1 to the counterweight 2. The motor 5 drives the drum 4 through suitable gearing mounted in the housing 6, thus effecting the raising and lowering of the car and counterweight. An electromagnetic brake 7 is applied to the motor shaft between the motor and the gear housing 6 forthe purpose of bringing the motor, and therefore the car and counterweight to a stop. Compensating ropes 8, connected at one end .to the car 1, pass under the compensating sheave 10 and at their other end are connected to the counterweight 2. The car butter is designated 11, while the counterweight buffer is designated 12. The upper limit switch 9 and the lower limit switch 19 positioned in the hatchway are arranged to be actuated upon overtravel' of the car by a cam 149 carried by the car. Thecontacts 169 of limit switch 9 and contacts '170 lim t wit ema niin engageme t ex.- cept when held separatedhy the cam .149. The car and counterweight guide rails are not shown for convenience of illustration.

According to the preferred arrangement, a cam 13 is secured to theconnterweiglit 21 A lever 14 is pivotally mounted, as on the shaft 18,-ne'ar-the bottom "of the hatchwayand carries a roller 15 'onone arinztheiteof. fThej roll er"1 5'-is;positioi' ied to'be e iigag'edby the earn 13. Dhe' remaining arm 'of 'leverfl'fextends upwardly and is formed with alcatchf l'ti at its upper-end. Catch-"16 ext-endspvei abutin'e'nt 47 secured to l-the lower' end of a lever 20. Lever 203s fulcruined "(iii the shaft p0 si'tione'din' the '*hatchway"-A rope 22 has its lower end'atta'ched to the lever -by the yoke23 'and pin-Q4; The upper portion of this rope extends over. sheaves 139 and 49pm s'itioned in tlie hatchway and is similarly atta 'ched to a lever"25 of'a rope clamp 26. The' rope clamp :26 ;i s"ar ra ng'ed near the top of theelevator hatchway, being'supported as on the I-beams 27 and securedtheret'o clips 159. This rope clamp is arranged to grip the s 'ies rqpe' i l ed ng e t e rum to the co interweighgat a point near the 4.

The constructionithe ropeclamp 26 illustrated in Figures 2, 3 and'4, 1 This'clamp p s a in 28 he n we sp ed. end parts 29- and '3qfconn'ected 'by two side plates 31"and'32. "The 'end'parts' ar of simiar co u t on and a edns l 't's eta-top and bottom portio i i.coiiriec ted; Central portion. The central portions are formed wlth grooves 33'and 34 a t theirsides; The

side plates

31 and 32 are of the same construction andhave tongues 35 and 36 fitting 1n the

grooves

33 and 34 of the end par'ts. Screws 39 extend through-the side plates and are threaded into the. end partsand serve to hold the end parts and the side platesconstituting the housing 28 together.

Lever 25, at a point intermediate its ends, is pivotally mounted on a shaft .37. Shaft 37 extends throughlugs38 40 formed on the top of end partz30'qf'the rope clamp housing and is retained in place as bycotter pins. The arm of thelever 25,:to1iwhich the op 2 a ta h ca es w defle t for cooperating with two fixed contacts, these pairs of cooperating contactsfbeing designated 41 and 42 The other a'rm of thelever 2 5 is widened for the greater part of" its lengthandis formed with an opening 43, the sides ofthe opening be'ing designated44 and 45. The ends of these sides'that'are farther from the pivotal shaft 37 are joined by a yoke 46. A Weight 47 straddles the yoke 46, being retained thereon by a set screw 48. Side 44 is formed with a bearing 50, having a bearing cap 51. Bearing cap 51 is secured to side 44 by' screws 52. Side is also formed with a bearing 53, having a bearing cap 54 secured to that side by screws 55. Adjacent the side 44 tandzwithin-the. opening 43 there:i .p itioned an equalizingban capable f. w g g in a vertical plane. This equalizing-bar has I a'pivotalstud projecting outwardly from its central portion and extending through the provided near the ends of the equalizing-bar 56'. fr djacent'the side45 and within the opening 43 'tliere'is also positioned'an equalizingbar 61 capable of swinging in a vertical plane. Tliis equaliaing bar has a pivotal stud 62 projecting outwardly from its central portion and'extending through the bearing 53. Circular ap rt resee and are provided near the nd i 'oifftlie'equ alizing bar 61. A cross- Bit-i165 'isjpo's'itionedlwithin the opening 43 has cylindrical end'portions extending K T 91 21 .?apertures 58 and 63 of equalizing- 56'land 61, Cross-bar 65 is retained in position with'respect to the equalizing-bars byj'tlh' e use jof cotter pins positioned at the extremitiesfof the cylindrical end portions. 'l lhif's tjoss'l)a1f t of rectangular cross-section excefftfiorfthos'f portions where it extends th'lfough'theequalizing bars and is provided wi t' h'an aperture 66 midway of its length. A-

yo}; jisipivot ally connected to the crossbar; means "of a pin '68 extending throilgliftheaperture 66 and the bifurcated end "o;f"" th'e yoke. cotter pin extends thi'gughpin 68 fat-each side of the yoke thereretainin'g thispin in place. The lower end of the yoke'67 'is formed into a tongue 70.1 Tongue 70'fits within the forked end of Stud 71 and is pivotally connected therewith inean's of a pin 72. 'The lower portion of the stud is threaded into a wedge 73 positioned within the clamphousing 28.

Cross 'bar' 75, of the same construction as the cross-bar 65, also is positioned within the-opening 43 and has cylindrical end orti'ons extending through apertures 60 an 64 ofthe equalizing-bars. Cross-bar 75 is likewise connected at its midpoint to a yoke 76. Yqke 76 is pivotally connected to the forked end of, astud 77. The lower end of the stud 77 is threaded into a wedge 78 positioned this recess a clamp 69 is retained as by means of a dove-tailed connection 89 between the wedge and clamp. Clamp 69 may swivel within recess 74 about a vertical axis extending

midway'between Wedges

73 and 78. The gripping face 82 of the clamp 69 is formed with grooves 85 and 86 that are concentric with and extend parallel to the hoisting ropes. Wedge 78 is of the same construction as wedge 73. The clamp 80 within wedge 78, as in the case of clamp 69, is free to swivel about a vertical axis extending midway between

wedges

73 and 78. Likewise the gripping face 83 of the clamp 80 is formed with grooves 87 and 88 that are concentric with and extend parallel to the hoisting ropes. The inclined face of the wedge 73 is designated 90. This face engages the inclined face 91 of a wedge 92.

Wedge 92 rests on the bottom portion of end part 29 of the rope clamp housing. Wedge 92 has a stud 79 projecting therefrom. This stud extends through the central portion of end part 29 and has a nut 157 and a lock nut 158 threaded on the end thereof. A compression sp ing 93 surrounds the stud 79 and extends between the wedge 92 and the central portion of the end part 29 of the housing. The inclined face of the wedge 78 is designated 94. This face engages the inclined face 95 of a wedge 96. Wedge 96 is of the same construction as the wedge 92 and rests on the bottom portion of end part 30 of the rope clamp housing. The stud 99 projecting from wedge 96 has a nut 160 and a lock nut 16], on the end thereof. A compression spring 97 is likewise interposed between the wedge 96 and the central portion of the end part 30.

' 100 is pivotally mounted, as on the shaft 101,

near the bottom of the hatchway and carries a roller 102 on one arm thereof. The roller 102 is positioned to be engaged by the cam 98.

The remaining arm of the lever 100 extends upwardly and is formed with a catch 103 at its upper end. Catch 103 extends over an abutment 104 secured to the lower end of a lever 1-05. Lever 105 is fulcrumed on the shaft 106 positioned in the hatchway. A rope 107 has its lower end attached to the lever 105 by the yoke 108 and pin 110. The upper portion of the rope 107 extends over sheaves 109 and 111 positioned in the hatchway and is attached to a lever 112 of a rope clamp 113. Lever 112 carries two contacts for cooperating with two fixed contacts, these pairs of cooperating contacts being designated and 116. Rope clamp 113 is arranged near the top of the elevator hatchway, being supported on I-beams 114 and secured thereto by clips 119. This rope clamp is arranged to grip the hoisting ropes, leading from the drum 4 to the car, at a point near the drum 4. -Rope clamp 113 is of the same construction as rope clamp 26 and therefore would appear to require no further explanation. v i

Referring to the wiring diagram of Figure 5, no attempt is made to show the coils and contacts'of the various electromagnetic switches in their associated positions, a straight diagram being employed wherein the coils and contacts of the various switches are separated in such manner as to render the circuits involved relatively simple. Also the parts of other switches and apparatus are separated in the interest of simplifying the diagram. For a clearer understanding of the invention, the stationary contacts of the switches are illustrated in cross section. It is to be understood that the control system illustrated is chosen merely for convenience of description.

The diagram shows a system comprising an elevator motor 5 and a car switch designated as a whole by the numeral 117 for controlling the operation of the motor. The motor 5 comprises the armature 118, series field winding 120, and the separately excited field winding 121. Stopping resistance 122 is provided for the motor armature 118. The release coil for the elevator motor electromagnetic brake 7 (see Figure 1) is designated 123. A double pole knife switch 124 is used for connecting the system to the

supply mains

125 and 126. In order to suit the type of diagram employed, the blades of this switch are shown separated. 127 is the safety switch in the car. Discharge resistances for the elevator motor field windings, and for the electromagnetic brake, together with the various door and gate contacts have been omitted to simplify the description.

The electromagnetic switches have been designated as follows:

A-potential switch,

Bup direction switch,

Cdown direction switch.

Throughout the description which follows, these letters, in addition to reference numerals, will be applied to the parts of the above enumerated switches. For example, contacts 13 145 are contacts on the up direction switch, while actuating coil A 128 is the coil that operates the potential switch. The electromagnetic switches are shown in their deenergized positions. 7

Upon the closing of knife switch 124 the potential switch actuating coil A 128 is energized, the circuit for such coil being from the left hand blade of switch 124, line 138, by way of line 130 through safety switch 127 in the, car, by way of line 131 through contacts 169 of limit switch 9, through contacts 41 and 115 of the safety appliances, through coil A 128, through the other contacts 42 and 116 of the safety appliances and through contacts 170 of limit switch 19. The potential switch, .upon operation, causes the engagement of contacts A 132-and A 133 preparing the circuits forthe-motor and the electromagnetic brake release coil. The condition of the circuits so far described might be termed normal. 1

The operation of the system is as follows:

Assume that the car is at rest at a lower terminal landing 59 (see Figure 1). In this positionof the car the cam 98 carried by the car is-above the roller 102 and does not engage this roller.- In order to start the car in the. up. direction, the operator moves the can switch into t;he position where its contact segment 134 bridges contacts 135 and Upon the. contact segment engaging contact 136, a circuit is completed tor the actuating coil B 137 of the up direct-ion switch. This circuit may be traced frem the left-hand blade of switch. 124, by way of line 138 and line 130, through safety switch 127,

contacts

135 and 136 of the ca r switch, by way of line 140, through contacts C 141 and (101i B 137, by way of line 142 to the right-hand blade of switch 124. Upon operation of the up direction switch in response to the encrgization of its actuating coil B 137, contacts B 143 and H.144 separate and contacts B 145, B 146' and B 147 engage. The separation of contacts B 143 breaks the circuit leading from the car switch down feed contacts 148, contacts B 143. and the corresponding down direction switch contacts G 1 11 serving as electrical interlocks. The separation of contacts B 144 and the engagement of contacts B 145 and B. 146 completes a circuit for the motor armature. This, circuit may be traced from the left-hand blade of switch 124, by way of line 138. through contacts A 132, by way of line 150 through contacts B 145 and contacts C 151, by way of line 152 through armature 118, back to line 138 through. contacts B 146 and series field winding 120, by way of line 142 through contacts A 133, to the right-hand blade of switch 124, Starting resistance and the accelerating switch for the motor armature have been omitted to simplify the description. The engagement of contacts B 145 also completes a, circuit for the brake release coil 123. This circuit may be traced from the left-hand blade of switch 124, by way of line 138 through contacts A 132, by way of line 150 throughcont-act's B 145, by way of line 154 through a portion of the stopping resistance 122, by way of line 155 through brake release coil-123, by way by way of line 155 through contacts B 147 by' way of line 15.6 through Winding 121, by way of line 142 through contacts A 133 to the right-hand blade of switch 124.

The brake release coil 123 being energized and current being su iiplied to the elevatormotor armature and field windings, the elevator motor starts, causingthe car to ascend- Assume that the car approaches the upper terminal landing 129 (see Figure 1) and the operator centers the car switch in order to stop. The disengagement of contact 136 and contact segment 134 breaks the circuit.- for the actuating coil B 137 thus permitting the direction switch to drop out tobreak the circuit for the motor armature and field windings and to cause the application ofthe brake T to stop the car. With the car at the upper terminal landing the counterweight cam 13- abcve the roller 15 carried by the lever 14 and does not engage this roller.

Under certain conditions of operation as for example should the operator fail to center the car switch and should the limit switches fail to function the car may run past the upper terminal landing to: the extent of causing the cam 13 to strike the roller 15. Roller 15 then rides outwardly along the inclined surface of the cam. This outward movement. of the roller 15 causes lever 14 to swing about its pivotal shaft 18 in a counterclockwise direction as viewed in Figure 1. Should the downward movement of the counterweight be above a predetermined amount,

the roller 15 will move outwardly to the extent of causing the catch 16 on lever 14 to disengage the abutment 17 on the lower end of lever 20. Lever 20 is now free to swing upwardly, releasing the tension in rope 22. lVeight 47 is thus permitted to fall turning lever 25 about its pivotal shaft 37. The turning of lever 25 at first causes the separation of the pairs of cooperating

contacts

41 and 42. These contacts on separating deenergize the actuating coil A 128 of the potential switch and the potential switch drops out to break the circuit forthe motor armature and field windings and to cause the application of the brake 7. causes the frame 81, pivotally carried thereby, to move downwardly, carrying with. it the

wedges

73 and 78. These wedges slide inwardly along the inclined faces 91 and 95' of the

wedges

92 and 96 respectively. Continned downward movement of the lever 25 will cause the vertical grooves in the oppos- The turning of lever 25 also ing faces of the

clamps

69 and 80 carried by the

wedges

73 and 78 to contact with and grip the hoisting ropes 3. The hoisting ropes, owing to their kinetic energy at this time,

are passing down through the rope clamp and hence assist in the continued downward movement of the

wedges

73 and 78. Farther downward movement of the

wedges

73 and 78 is accomplished by compressing the

springs

93 and 97. These springs thus yield causing the hoisting ropes to be gripped between the

clamps

69 and 80 with a force increasing in magnitude as

wedges

73 and 78 move down ward within the housing 28. Should the

wedges

73 and 78 move to the extent of engaging the'bottom of the housing, 28, no further deflection of the

springs

93 and 97 can take place and the gripping force of the

clamps

69 and 80 upon. the hoisting ropes thereafter is constant depending upon the strength of the springs.

The ,kinetic energy of. the portion of the hoisting ropes extending downwardly from the rope clamp 26 to the counterweight is thus diss' ated and these ropes are brought to rest. n the event that the counterweight has not been brought to rest by the butler 12, or by engagement with the bottom of the hatehway as in the case where a buffer is not employed, the kinetic energy of the counter weight is likewise caused to be dissipated. With the rope clamp 26 carrying the pull of that portionof the hoistingiropes extending below this clamp, the pull of this portion of the ropes on the drum 4 and on the car ceases.

in Figure 1, should the potential switch fail to drop out for any reason so that the motor '5 continues to operate, thetractive effort of the drum 4 upon the hoisting ropes .leading to the car is reduced'to a negligible quantity and the hoisting drum s'lides'with respect to these ropes, so that the continued rotation of the motor does not tend to raise the car.

As has been previously indicated,

wedges

73 and 78 are connected'by yokes to the midpoint of the cross-bars constituting a part of the frame 81. Since the cross-bars are carried by the ends of the equalizing-bars, at equal distances from the pivotal. supports of the equalizing-bars, it follows that the wedges 73 and 78gare'connecte'd to the frame 81 at equal distances from such pivotal supports. The downward force applied to one of these wedges is' therefore always equal to the downward force applied to the other. One wedge may move downwardly .at a different rate of speed from that of the other. caused as by a difference in strength of the compression springs 93 and 97. Nevertheless. owing to the equalizing of the forces acting upon the the bufier 11.

wedges, they move in a vertical path and do not deflect the hoisting ropes. Inasmuch as the

clamps

69 and 80 are tree to swivel within the

wedges

73 and 78 these clamps apply equal retarding forces to the separate hoisting ropes. By adjusting the

nuts

157, 158 and 160, 161 the

springs

93 and 97 may be placed under no initial compression or under any initial compression that may be desired, depending upon the requirements of the particular installation. An initial vertical adjustment of the

wedges

73 and 78 may be obtained by turning studs 71 and 77 with respect to the wedges. The maximum retarding force that may be applied by the rope clamp to the hoisting ropes will depend upon the strength of the

springs

93 and 97. This maximum force exists when the

wedges

73 and 78 rest upon the bottom of the rope clamp housing 28. By choosing springs of appropriate strength any desired retarding force may be obtained.

To operate the elevator car in the down dirrection the operator positions the car switch so that its contact segment 134 bridges contacts 164.- and 148. The actuating coil C 165 of the down direction switch being energized, contacts C 1 11 and G 151 are separated and contacts C 166. C 167 and C 168 are engaged.

Current now flows through the motor armaated for causing the car to run. past the landing 129,, the car may continue past landing 59 to such an extent that cam 98 strikes the roller 102 carried by the lever 100. Should the car continue in its course a'predetermined extent, the lever 100 will release lever 105 in same manner, that rope clamp 26 operated,

causing the separation of the pairs of coopcrating contacts 115 and 116. the dropping out of the-potential switch. the breaking of the current to the motor armature and field windings and the application of the brake as before. The car will be brought to rest by That portion of the hoisting ropes extending between the rope clamp 113 and the elevator car will be retarded and finally supported by the rope clamp. The counterweight thus relieved of the pull due to the hoisting ropes will come to rest with gravity retardation and without striking the upper limit of the hatchway.

The safety appliances may be reset manually. For example. if the safetv appliance actuated by cam 13 has operated. it may be I reset by raising the rope clamp lever 25." -Initial movement of this lever causes the

clamps

69 and 80 to release the hoisting ropes. Further movement of the lever 25 causes the reengagement of the pairs of cooperating

contacts

41 and 42. The system may now be started in operation to cause the disengagement of the counterweight cam 13 from the roller 15 of the lever 14. Thereupon the lever 14 may be swung so that its patch 16 again engages the abutment 17 on lever 20 thus completing the resetting operation.

For convenience of illustration the rope clamps are shown for operating upon two hoisting ropes but it is to be understood that they are equally as well adapted for operation upon any number of hoisting ropes. For example when four hoisting ropes are employed, certain portions, such as the Wedges n prings, f. ach op lamp, a up i a e r h two addi ional rop s In such case the dimensions of the housing, frame, and weighted lever tor each rope em a e made with a te accommo a t g ea e shutte ee Sa ety epphahe aet ated hv ea n 1 on the counterwweight may; asreadily be ache e y a cam. ehthe tar as it approac th ppe lim t of. the hatehwey y merely Placing e rol er 15 .ah conne ted mec h sm i the peth i tra of the cam. carr e by h e L heivise the sa ety apeha nc th edby hm. on he i av he actuated by aga n on the counterweight. Such n art ns iheht s illu trated n Figure 6,

AS m ny hahg s. cou d. he made i th above iqh. and .ihehy apparently Wi ly difier ht embodiments hi this inv iehfe' ld hie-made W thout depa t ng om t s op e s ft, t i intendedthat a1 matterv ntain d, in. the abo e escg ptioh, o

h hfii t'h aee xh .enyihg dre v-mgsshal be nt pret as im ing Sense-r Wh Si h 6 :i .2, f Ah ele a r system compris ng, a ca an e h te weishtih he hhtehveyya riv s h e. hhie ihg ropes connected toth r n c un rw ig t and. pass ng o er sai ngee e a d m an ionerated by th i ustt t ve. ahd n t in e r' is t1 or ae hs upon. he hei t-i g p s to use th stepp ng he car n it w d. t av ith su stan ia ly gravity retardation,v

2. elevator. system. comprising, two

mo e bodies i he. hat h-way, hoistin p s e he hg sa mo able hed es, m an or pp ng the escend ng bo y, fo r p s h i t g r p s, nd. actui y h ndi g b dy as t c m t rest for. causing theapplication of the gripping means. e

3. An elevator system comprising, two movable bodies int-he hatchway, a plurality of hoisting ropes connecting said movable bodies, and a safety appliance mounted in the hatchway comprising means for gripping all of said hoisting ropes with equal pressures, and means for normally retaining said gripping means in its inoperative position, said retaining means being arranged to be actuated by one of the movable bodies to cause the ap' plication of the gripping means.

4. An elevator system comprising, two oppositely movable bodies in the hatchway, hoisting ropes connecting said movable bodice, and a safety appliance comprising a hoisting rope gripping means mounted near the top of the hatchway and a connected releasing mechanism mounted in the hatchway, said releasing mechanism being adapted to be operated by the descending body as it comes to rest to cause the operation of the hoisting r pe gr pp g ans,

5. elevator system comprising, two oppositely movable bodies in the hatchway, hoisting ropes connecting said movable bodie s, a buffer engaged to stop the descending body as itreaches its lower limit of travel, a cam mounted on said descending body, a rope. clamp mounted near the top oi the hatchway and comprising a housing with cooperating wedges ther in and actuating means tor causi s-said wedges to rip o ing reres above the descending body, releasing means connected with said actuating means and comprising a device in the path of travel of said can], said cam striking said device, upon the stopping of the descending body, and causing the releasing means to release the actua ing m ns, and efi e th epe tion of the rope clamp.

for raising and lowering the car and counterweight, a brake for the motor, a hufl'er for the .car, a buffer for 118 counterweight, a safety appliance for gripping the hoisting ropes supporting the'o unter e gh and for 68118- hg e deene giza ion. of h or a d h appl cation of the b t tke to stop themotor, said counterweight causing the operation of sa s f y pp i eein the e nt ha it buffer s mpressed a pre e m n d m n a an ad nal afe y appl a e o g ip- P gthe hoist g op s supp rting h ear n for caus ng t dee g z tion of th m er and th hp-p ieat en of th b ake to s ep th m r, said causing t e ope a-- tion of said additional safety appliance in the en t t s hufi r is compr sed a pred eri ed amo n 7- I an elevato sy em, a m v b eody in the hatehway, a hoisting drum positioned in the upper portion. of the hatchway, hoistpe ex nd ng f m sa h i in drum o s i m ab e. bo y, nd. mean m un d i the hatchway near the hoisting drum for gripping the hoisting ropes said means being operable by said body as it descends,

8. In an. elevator installation, the combination of a drum, means to rotate the drum, a cable passing over the drum, a load connected to the cable on each side of the drum, the

Weight of said cable and load normally causing a frictional engagement between the cable and drum sufiicient to drive the cable in either direction that the drum rotates, and means actuated by a downwardly traveling part of the device, as a load approaches its lower limit of travel, to render the drum drive ineffective, even though the weight of the long reach of cables is suflicient to normally cause traction enough to continue the drive.

9. In an elevator installation, the combina tion of a drum, means to rotate the drum, a cable passing over the drum and having a reach depending at each side thereof, a load connected to each reach, the engagement between the drum and cable being so constructed that the latter will be frictionally driven when the weight supported at one side of the drum differs from the weight supported at the other side thereof by less than a predetermined ratio, and means actuated by either load, as it approaches its lower limit of travel, to render the drive ineffective by disturbing said ratio.

10. In an elevator installation, the combination of a drum, means to rotate the drum, cables passing over the drum and provided at each end with a load, gripping means located above the normal limit of elevator travel. a tripping device near the lower limit of elevator travel and engageable by one of the loads as it approaches its lower limit of travel, and means connected to the tripping device for causing said gripping means to grip the cables when the tripipng device is so engaged.

In testimony whereof, I have signed my name to this specification.

FREDERICK HYMANS.