US1159563A

US1159563A - Safety device.

Info

Publication number: US1159563A
Application number: US71784012A
Authority: US
Inventors: William D Baldwin; Griffith John
Original assignee: Otis Elevator Co
Current assignee: Otis Elevator Co
Priority date: 1912-08-30
Filing date: 1912-08-30
Publication date: 1915-11-09
Anticipated expiration: 1932-11-09

Description

W.'D. BALDWIN & G. JOHN.

SAFETY DEVICE.

APPLICATPON FILED (5.30. 1912.

Patented Nov. 9, 1915. 5 SHEETS-SHEET l.

( 3 LUVCEBS W. D. BALDWIN (3L G. JOHN. smw DEVICE.

APPLICATION FILED AUG-30, 1912. 1 159 53,, Patented Nov. 9, 1915.

5 SHEETSSHEET 2.

W. D. BALDWIN & G. JOHN.

SAFETY DEVICE.

APPLICATION FILED' AUG. 30. 1912.

Patented Nov. 9, 1915.

5 SHEETS-SHEET 3.

w. 0. BALDWIN- & JOHN.

SAFETY DEVICE.

APPLICATION FILED-AUG. 30. 1912.

5 1 m4 IT 9n H 4 08 NH am es m LAW. a P

"Z; ju M W. D. BALDWIN & G. JOHN.

SAFETY DEVICE. 19159953 APPLICATION FILED AUG. 30. I912. Patented NOV. 9 1915.

5 SHEETSS HEET 5.

WITNESSES. mm a am yum 16M entra n snares Parana cannon.

WILLIAM n. BALDWIN, on NEW YORK, Ann GRIFFITH JOHN, or YONKERS, new YORK,

ASSIGNORS TO OTIS ELEVATOR COMPANY, OF JERSEY CITY, NEW JERSEY, A COR- PORATION OF NEW J ERSEY.

sarnrv nnvIcE.

Specification of Letters Patent.

Patented Nov. Q, 1915.

Application filed August 30, 1912. Serial No. 717,840.

, T all whom it may concern Be it known that we, WILLIAM D. BALD- WIN, a citizen of the United States, and GRIFFITH JOHN, a subject of the King of Great Britain, residing, respectively,in New York, in the county of New York and State of New York, and*Yonk"ers, -county ofWestchester, and State of New York, have in vented anew and useful Improvement in Safety Devices, of which the following 1s aspecification.

Our invention relates toimprovements in safety devices for elevators and more particularly to that-type of safety device or brake in which gripping jawscarried by the -car or counterweight or both are adapted to grip the stationary vertical guide ralls or their equivalent in the hatchway.

One object of the invention is the provision of a safety device which will operate with varyin power.

Another 0 ject is the provision of a safety device which may. be controlled electrically and mechanically.

A further object is the provision of a safety device which will-operate to retard and stop an elevator-in the event of excessive speed with a predetermined braking power which braking power may be substantially increased should the speed further increase or the hoisting cables part.

Other objects of the invention will appear hereinafter, the novel combinations of elements being pointed out in the appended claims.

In the accompanying drawings, Figure 1 represents an electric elevator system containing an embodiment of our invention; Fig. 2 is a bottom plan view of the safety device carried by the elevator car; Fig. 3 is a similar view of the safety device carried by the counterweight of Fig. 1; Fig. 1 is a modification; Fig. 5 is a further modifica tion; Fig. 6 is a view of an elevator car equipped with the modified safety device shown in Fig. 5; -Fig. 7 is an electric elevator installation in which both the car and counterweight are equipped with the safety device shown in Fig. 5.

In Fig. 1 is shown an elevator car 0 and a counterbalance weight W which are connected to, and suspended from, the hoisting cables II. A motor M is associated with the cables II, and operates to move the car and connected counterweight over the vertical guide rails G.G. The motor M may be of any desired type such as steam, hydraulic, GlBCtIlC'OI' other suitable power, but for purposes of illustration we show a direct drive electric elevator of the traction type. The motor and the idler or tension sheave I may be mounted upon the overhead beams B as shown, or located in any other suitable place as desired. Secured to the bottom of the car and counterweight are clamp jaw safeinwardly extending arms of the clamps 22 between which are located the wedges 88. In Fig. 2 these wedges are carried upon solenoid cores 7'7 which are surrounded by magnet windings '12-12 located in the magnet frames 11 secured to the channel beams 15-15. Under normal conditions the magnet windings 12-12 are energized from a suitable source of electrical energy and the cores 77 are drawn inwardly against the action of the springs 9-9 which are located between the magnet frames and the collars 10'-10, respectively, thereby releasing the safety clamps 22 from the guide rails. Other cores such as 6-6 are surrounded by the magnet windings 1212 and are rigidly secured to the right and left hand screwthreaded rods 55, respectively, These rods are threaded into the hubs of the safety drum 4. and are supported in bearings 1313 secured to the channel beams 1515, and are prevented from turning by means of feathers 16 16 or other suitable device.

It will be observed that when the magnet windings 1 212 are energized, the cores 77 will move into contact with the cores 6-6, respectively, and. the safety clamps will move into released position. If, however, these magnets be deenergized by interrupting the electrical circuit therethrough, the springs 99 wili apply the safety clamps with a predetermined pressure. Furthermore-if the drum I be rotated in the lot are

proper direction, the threaded rods 5-5 will be moved outwardly thereby moving the cores 6-6 against the cores 77, respectively, and forcing the wedges 88 between the rollers 14--14, to increase the gripping power of the clamp jaws on the guide rails. From the foregoing it is seen that the mag nets effect an electrical means for operating the safety device, while a rotation of the safety drum 4 efiects the operation of the safety by mechanical means. Each of these means acting alone will operate the safety device or they may act concurrently and intermittently, the operation of one means in no way interfering with the operation of the other. The power exerted by the drum and screw mechanism may be limited and regulated by the weight attached to the tension sheave 21, or by the number of turns of the governor rope around the drums 4L and 1, or by both. Since the governor rope is not made fast to the drums, but merelyin frictional engagement therewith, it will slip upon the tension exerted upon the governor rope reaching a predetermined value less than what. would injure or unduly strain the rope. For instance, after full power has been exerted, to tighten the clamps on the guides, the car, by reason of the heavy load, may continue to move a short distance farther, tending to place an excessive strain on the rope. prevent breakage of the rope, therefore,

- we arrange the apparatus so that the rope may slip.

The magnets 12-12 have ample power to resist the action of the springs 9-9 when the magnets are energized with the cores 6 and 7 in contact with each other, and if desired they may be sufficiently powerful to effect the release of the clamp jaws after the same have been applied by the electrical means. In some cases, we prefer to arrange the magnets so that they will normally overpower the tension springs 99 only when the cores are substantially in contact, but will not have sufficient power to effect the release. of the clamp jaws after the same have operated. In this instance the release of the clamp jaws is effected by mechanical means operable from the car and comprising a pair of levers 52-52 pivoted to the chan-' nel beam 15 and adapted to be actuated by means of flexible cables 5353 connected to a small winding drum -54. The latter is provided with a square socket 55 which re ceives the squareend of a wrench carried in the car. Springs, such as 56-56 maintain the levers 52-52 out of engagement with the collars 1010 upon the cores 7-'7, respectively, and prevent the levers from in terfering with the operation of the safety device. After the magnets have been deenergized and the wedges 88 moved outwardly by the springs 99, the winding In order to.

drum 5 1 may be rotated, thereby swinging the levers toward the center and moving the cores back to their original position. A circuit being again closed to the magnets l212, the latter will maintain the safety clamps in released position and the springs 5656 will move the levers into their noninterference position, as shown.

As before pointed out, the safety device carried by the counterweight, and shown in Fig. 3,-is similar in certain respects to that just described, but is without the electrical features. That is to say, the right and left hand screw-threaded rods 5'-5' are connected directly to the wedges 8-8, and are prevented from turning by means of the pin-and slot connections 17 -17 or other suitable arrangement. One end of the safety drum 4 is supported for rotation in the bearing 13, while the other end is tapered and engages a corresponding taper formed in the left hand bearing 18. A spring 19 forces the drum into frictional engagement with the tapered portion of the bearing 18, thereby forming a retarding device or friction brake tending to prevent the drum from rotating.

Turning now to Fig. 1, it will be observed that an endless safety cable 19is wrapped several times about the drums 4 and 4, of the car, and counterbalance safety devices,

respectively, and leads up over a guide pill-- ley 20 at the top of the hatchway and is maintained under a predetermined tension by means of a weighted sheave 21 arranged in suitable guides at the bottom of the hatchway. A centrifugal governor 23 is driven by the hoisting motor through the bevel gearing 24, and controls a pair of electrical contacts 25 which are normally in electrical engagement with each other, but become separated by the governor whenever the motor, and consequently the elevator car, exceeds a predetermined speed in either direction. The electric contacts 25 are connected .in series with the contacts of a safety or emergency switch 25 in the elevator car and this circuit controls the circuit through the electromagnets 1212 on the safety device and potential switch 26. VVhile'it is practical to connect the governor contacts, safety switch 25 and safety magnets 1212 in series across a suitable source of electrical energy, we prefer the arrangement shown in Fig. 1, since this arrangement possesses certain advantageous features. The control of the elevator is effected from a manual switch 27 in the car, the handle of which may be moved to one side or the other to energize one of the reversing switches- 28-29, to complete a circuit to the armature and field of the hoisting motor M, the armature and field terminals being shown at 30 and 31, respectively. A starting resistance is shown at 32 which resistance is automatically cut nmates out or short-circuited by means of an accel crating magnet 33 in the usual manner.

We have not shown the customary electric brake for the motor, since the same would only confuse the drawing and forms no part per se of our invention. v

The potential switch 26 comprises a pair of contacts and 36 which are connected through a main line switch 34 to the positive and negative mains, and respectively. In order therefore to enable the elevator to be operated, it is necessary manually to close the contacts of the potential switch, whereupon the said switch will remain closed providing the main line potential is not too low, since itsmagnet Winding is self-hold- -ing. The circuitof this magnet may be traced from the positive main at the contact 38, through the winding of the potential switch, governor contacts 25, emergency switch 25, and, by way of the

contacts

39 and 36 to the negative main. The circuit to the magnets l2-12 of the safety device may be traced from the positive main, through the

contacts

35 and 37, terminals 22, conductors 40 and 41,

contacts

39 and 36 to the negative main. From the foregoing, it is seen that the potential switch will remain closed so long as the. motor does not attain excessive speed and provided the emergency switch 25 remainsolosed. Furthermore, as long as the potential switch is closed the magnets-of the safety device will be energized and the gripping jaws will remain in normal released position. Should the motor attain excessive speed, the governor will interrupt the self-holding cir cuit of the potential switch and the latter will open its contacts, thereby open circuiting the magnets of the safety device and the latter will operate to retard and stop the car. The emergency switch in the car may be operated at any time to effect the same result, while any undue fall of potential in the supply circuit will permit the potential switch to open and apply the safety clutches.

In order to effect a driving connection between the elevator apparatus and the safety cable 19, we have provided! the friction brake or clutch associated with the drum 4' of the counterweight safety device. Under normal running conditions the safety cable travels with the car and counterweight, and at the same speed, and the safety drums 4;

and l on the car and counterweight, respectively, will not rotate. If however, the hoisting cables should part or the driving sheave on the motor be broken or the elevator machinery become disarranged so as to permit the car or counterweight to fall or have a movement relatively to thatof the safety cable 19, the drums 4 and 4 would rotate in a direction to move outwardly their respective screw threaded rods to ef feet the application of the clamping jaws to the guide rails to retard and stop the car and counterweight. Forinstance, let us suppose that the car and counterweight are at rest, and thehoisting cables should part. The car and counterweight will at once'tend to fall,'and exert a downward pull upon the opposite leads of the safety cable. As the counterweight moves downwardly, the corresponding lead of the safety cable is carried along with it, due to the fact that the drum t is not free to turn, hence the safety .drum 4 on the car will be rotated in an anticlockwise direction to apply the car safety. The car itself will also move downwardly which movement in itself will tend to rotate the safety drum 4 in the same direction. As soonas the clamping jaws on the car have engaged the corresponding car guide rails, the drum 4 meets with a rapidly increasing resistance opposing its turning movement. which soon becomes of greater function, i. 6., in the event of excessive speed, the governor automatically effects the operation of the safety device by electrical means and with a predetermined pressure which pressure is regulated by the tension of the springs 99. While the hoisting cables remainintact, the braking power should be moderate and just sufficient to retard and stop the unbalanced load, which, by'means of our invention is efficiently accomplished by means of; the springs. In case the hoisting machinery should become disabled or the cables part, it is desirable substantially to increase the braking power, since the load is no longer partially or wholly balanced but represents dead weight. This we acoomplish by means of the right and left screw mechanical safety device as already described. One valuable feature associated with the electrical safety device is that when the elevator is out of service and the main line open at the switch 34, the springs will apply the clamping jaws to the guides to maintain the car stationary,and, since in all likelihood this switch will be opened at least once every day, for instance at ni ht, the safety device is periodically called into play, which enables one readily to ascertain. whether or not the safety device is in good operative condition. Elevator safety devices are, as a rule, not called into action for long periods of time, and by reason of disuse they are very apt to become disabled from various causes and refuse to perform their functions when the time comes.

It will be observed that the mechanical safety device operates to retard and stop both car and counterweight, while the electrical device is applied to the car safety alone. Under certain conditions it may be desirable toequip the car and counterweight with both electrical and mechanical safeties. This may readily be done with the apparatus shown in Fig. 1 by merely substituting the safety device shown in Fig. 2 for the device on the counterweight shown in Fig. 3 and connecting the magnets of both devices in series. This arrangement is substantially that shown in Fig. 4, a description of which will now be given.

Referring to Fig. 4 it willbe seen that the combined electrical and mechanical safety device shown in Fig. 2 is applied to both the car and counterweight. The electromagnets of each of these safety devices may be connected in series with each other and in series with the governor switch and the emergency switch on the car, the electrical energy for maintaining both safety devices in normal released position being supplied from the positive and negative mains designated by and extends the full length of the hatchway and is driven from the car by means of the usual releasing carrier 42. A governor clamp 46 of any desired construction is controlled by.

the governor 23 and while the same permits the cable to run freely under normal conditions of car speed it will operate to clamp the cable against movement in either direction should the car speed become excessive. The opposite leads of the governor cable-are connected to other cables 44-44 which in turn are Wrapped about the drums 4 and 4 of the car and counterweight safeties, respectively, and made fast thereto. The governor itself is driven by the cable 19 and controls both the electrical and mechanical safety devices through the contacts 25 and clamp 46, respectively. It is desirable to have the governor effect the opening of the contacts before the car has reached a speed suflicient to operate the clamp .46. Thus if the car attains a predetermined speed the electrical safety will act, and, if for some reason the car should further increase its speed the clamp 46 will immediately operate to apply the mechanical safety no matter what direction the car maybe traveling. The handle 50 in the car is connected by a cable to the safety drum which arrangement enables one in the car to apply the mechanical safety device at any time. Under ordinary conditions the operation of the electrical safety alone will be sufficient to retard and stop both car and counterweight, but in event of that failing, the mechanicallyop The governor cable 19 eratedsafety will effect a powerful and positive stop under all conditions of load and speed. Should the cables part or the ma' chinery become disabled so as to permit the car and counterweight to fall, both mechanical'safeties will at once operate to stop both car and counterweight.

Referring to Figs. 5 and 6 it will be seen that the device therein shown is'a combined mechanical and electrical safety mechanism, in which we propose to utilize cams for effecting the application of the safety clamps instead of the right and left screws, of Figs. 2 and 3. The arrangement may be carried upon the car and counterweight or both, and comprises a pair of cams 60 and 61 of substantially spiral form secured upon a vertical shaft 62, which shaft also carries-the operating sheave or drum 63 (Fig. 6). These cams are similar in construction and are arranged adjacent each other and 180 apart.

Cam rollers 59-59 are adapted to be in' rolling contact with the cams 60 and 61, respectively, and are placed upon opposite sides of the shaft 62. Each of the rollers, such as 59, is carried in a bracket 58 formed integral with a magnet frame 11 and boss 57, the latter being hollowed out so as to avoid unnecessary weight and acts as a support and guide for the roller 59 and connected parts. A guide bracket 13 embraces the boss 57 and is secured to the channels 15-45 by bolts or other suitable fastening. The magnetcore 7 extends into the solenoid magnet 12 and carries upon one end the wedge 8 which effects the application of the clamping jaws 2-2 upon the guide rail G, by forcing apartthe rollers 14-14. A spring 9 tends to move the core 7 outwardly to operate the safety device, but is normally kept from doing so by reason of the mag'net'12 which maintains the core 7 in close contact with a corresponding fixed core 6 formed integral with the magnet frame 11. The operating sheave 63 (see Fig. 6) has wrapped about it several turns of the governor cable 19 which is actuated at car speed through the medium of the releasing carrier 42 and runs up over the governor 23 and down around a tension sheave 21. The governor controls the cable gripping clamps 46' and a pair of contacts 25, which contacts, together with an emergency switch 25 in the car, are connected in series with the magnets 1212 across the terminals of a supply circuit at the main line switch 34. The end of the shaft 62 is squared, so as to receive the socket of a wrench 64 in the car by means of which the safety device may be operated by hand at any time or may be reset after having been operated.

The operation of the device just described is effected automatically by the governor when the car attains too high a speed, the governor operating to separate the contacts 25, thereby interrupting the circuit of the magnets 12-12, and permitting the cores 7-7 to move outwardly under the action of the springs 9-9, thereby setting up the clamping jaws on .the guide rails with a' pressure depending upon the tension of these springs. Should, for any reason, this operation fail to retard the car, a further increase in car speed enables the governor to trip the governor clamps -46, thereby disconnecting the governor cable from the car at the releasing carrier i2 and causing the continued downward motion of the car to rotate the sheave 63 and shaft 62, together with the cams 60 and 61. The cams will rotate in a left hand or anticlockwise direction, and, -royving to the spiral form of the same, will gradually and powerfully -move outwardly the rollers 59 59, thereby moving outwardly the magnet frames l111, and compressing the springs 99. Acontlnua- V tion of the movement eventually carries the core 6 into contact-With the core 7, and the action thereafter is positive and of great power being limited by the friction of the governor cable about the sheave 63 which may readily be predetermined as before pointed out in connection with the apparatus shown in Fig. 1.

It will be observed'that in certain respects the operation of the cams is preferable to that of the right and left screws of Figs. 2 and 3, for the reason that it is a simple matter to design the cams so as quickly to effect the actuation of the clamping jaws immediately the governor rope is gripped by the governor clamps, and thereafter to efiect a slower and more powerful grip action. The action of the right and left screws is necessarily less prompt and requires more time to actuate the jaws than does the cam mechanism, since the pitch of the screws cannot well be varied beyond certain practical lim-- its, which have been determined by experiment and the results shown in actual use. While the cam actuated safety is a complete operative device in itself, its value is greatly enhanced by reason of the cooperation between it and the electrically operated safety. For example, the governor is preferably adjusted to operate the electrical safety before the mechanical safety, and thus the elevator car is subjected to a-certain predetermined brake action tending to bring the same to rest. Ifthe hoisting cables remain intact the safety device is merely required to arrest the unbalanced load, and the clamping power of the safety device effected by the spring alone is suflicient to accomplish this result. If, however, the hoisting cables should part, it is of course obvious that a greater braking power must be brought to bear in order to arrest the unbalanced car and whatever load it may be carrying. The mechanical safety device 'of the safety device is immediately effective before the car has had time to attain a dangerous speed.

It will be further observed that in the operation of the combined mechanical and electrical safety device, no time is wasted in taking up lost motion in any of the parts. As soon as the magnets 1212 become dee'nergized and the springs 9-9 have moved the core 7 outwardly, the operation of the cams carries the magnet, frames 11 outwardly, thereby compressing the springs and increasing the braking power of the clamp-jaws. This braking power continues to increase until finally the cores 6' and 7 are brought in actual contact with each other, and the further rotation of the cams effects a further and positive outward movement of the cores 77 and their attached wedges which effects a very powerful brake action to arrest the car under the most severe conditions of speed and load. The governor may be adjusted so 'as to effect a successive operation of the electrical and mechanical actuating devices, as described, or if desired their operation may be effected simultaneously, or the governor may actuate the cams before the circuit of the magnets is interrupted. This selective feature is of value since the proper sequence of operation is made optional and may be arranged so as to effect the best results in practice. We have provided means for doing this, the said means comprising the adjustable lower governor contact 25 which is spring pressed and has a predetermined movement toward its coacting upper contact. I

The magnets of Fig. 5 may be made sufficiently powerful to effect the release of the safety device, by merely closing the circuit through their respective windings, or they maybe made justsufficiently powerful to retain the cores in contact when the same are brought together by other means. In this last instance, we provide the arrangement alreadyrdescribed in connection with Fig. 2, and comprising the levers 52-52, cables 53-53 and winding drum 54. This arrangement is merely typical, since it is obvious that various other mechanical contrivances could just as well be used to effect the desired result.

From the foregoing it will be seen that an elevator system containing an embodiment of our invention is amply protected against excessive speed or falling. When the conditions are such that it is only necessary to retard and stop an unbalanced load, the safety device will operate with the neces sary power .to eflect the desired result. Should the conditions be such that it is required to retard and stop a load in excess of the unbalanced load, the power of the safety device maybe increased to an amount sufficient to meet these requirements, hence ample provisionis made by a safety device constructed according to our invention for taking care of every contingency that may arise during the operation of the elevator or while the same is at rest.

It is obvious thatone skilled in the art may make various changes in the details of construction and arrangement of parts without departing from the spirit and scope of our invention, and we desire therefore not to be limited to the precise construction disclosed.

What we claim is 1. In an elevator, the combination of a safety device, and electrical and mechanical automatically operable means, operable independently of each other for efiecting the actuation of the safety, the mechanical means being operable independently of the speed of the car. i

2. In an elevator, the combination of a safety device, speed-controlled electrical mechanism for actuating said device with a predetermined pressure, automatic mechanical means independent of the speed of the elevator for operating said device with increased pressure, and manual means for controlling said electrical mechanism.

3. In an elevator, the combination of a safety device, a governor, electrical means controlled by the governor for operating said device with a predetermined pressure, and separate mechanical means for effecting the automatic operation of the said device with increased pressure independent of the speed of the elevator.

4. In an elevator, the combination of a safety device, automatic means for actuating said device with a predetermined pressure, .and independent automatic means operable independently of the speed of the elevator for increasing said pressure.

5. In an elevator, the combination of a safety device, electrically controlled auto: matic means for actuating said device with a predetermined pressure, and independent automatic means operable independently of the speed of the elevator for increasing said pressure.

6. In an elevator, the combination of a safety device or clutch, of a spring for operating said clutch with a predetermined pressure, an automatically operated electroresponsive device controlling said spring, and automatic means independent of said spring operating means for actuating said clutch with increased pressure independent of the speed of the car.

7. In a safety device for elevators, the combination of a car, guides therefor, a brake device for the car, electrically con- 8. In a safety device for elevators, the

combination of a car, guides therefor, a clamping device carried on the car and adapted to engage said guides, a spring for operating the clamping device with a moderate pressure, electroresponsive mechanism controlling said spring, automatic means for controlling said mechanism, and separately operated -means arranged automatically to increase the pressure of the clamping device on the guides, said last named means being independent of the speed of the car.

9. In a safety device for elevators, the combination of a car, guides therefor, a clamping device on the car adapted to coact with said guides, electrically controlled spring mechanism for automatically operating the clamping device with a moderate pressure, and a screw independently operable for operating the said clamping device independently of said. spring mechanism and with increased pressure, said screw operable independently of the speed of the car.

10. 'In a safety device for elevators, the combination of a car and counterweight, a safety clamping device for the car,a safety clamping device for the counterweight, and mechanical and electrical operative connections between both of said clamping devices.

11. In an elevator, the combination of a car and counterweight, a safety device on said car, a safety device on the counterweight, and a speed controlled mechanical connection between said devices whereby the operation of one of the said devices is dependent upon that of the other.

12. In an elevator, the combination of a car and counterweight, a safety device on. the car, a safety device on the counter weight, and a governor controlled cable connecting said devices, substantially as described. v

13. In an elevator, the combination of a car and counterweight, a safety device on the car, a safety device on the counterweight, and a single operating'means comprising a. speed governor for both of the said devices.

14. In an elevator, the combination of a car and counterweight, safety clamping devices for both car and counterweight',-and a running rope adjacent the car and counterweight arranged to effect the operation of said safety devices upon excessive car speed.

15. In an elevator, the'combination of a car and connected counterweight, a safety device on the car and a safety device on the counterweight, a. drum associated with each safety device for actuating the same, a runtion of one of said drums, the operation of which places a further tension upon said running rope to effect the operation of the other of the said drums.

16. In an elevator, the combination of a 'car and counterweight, suspension cables therefor, safety clamps on said car and counterweight, a speed controlled, running cable connected to and arranged to actuatesaid safety clamps, and means for placing a tension on said running cable to actuate the safety clamps with a predetermined power when the ,tension on the suspension cable is varied beyond predetermined limits.

17. In a safety device for elevators, the combination of a car, guides therefor, a brake device for the car, means for applying the brake to the guides with a limited pressure, additional means automatically to increase the pressure of the brake on the guides, and means within the car for elec- 'trically controlling the application of and resetting the said first named means for ap plying the brake.

18. In a safety device for elevators, the

combination of a car, guides therefor, gripping jaws carried on the car and adapted to clamp the guides, a spring for operating the gripping jaws, an electro-magnetic device controlling said spring, a cam. device foreffecting the operation of the gripping jaws, and means controlled by the speed of the car for operating said electro-magnetic and cam devices to effect the actuation of said gripping jaws. I In an elevator, the combination of a car, guides therefor, a clamping device on the car adapted to engage the guides to retard and stop the car, electrically-controlled spring-actuated mechanism for operating said clamping device, cam mechanism for operating said device, and means for effecting the successive operation ofboth of the said operating mechanisms.

20. In an elevator, the combination of a car, guides therefor, a clamping device on the car adapted to engage the guides to retard and stop the car, electrically-controlled springactuated mechanism for operating said clamping device, cam mechanism for operating said device, and a single means for effecting the operation of both of the said operating mechanisms.

of two subscribing witnesses.

21. In an elevator,'the combination of a car, guides therefor, a clamping device on the car adapted to engage the guides to retard and stop the car, electrically-controlled spring-actuated mechanism for operating said clamping device, cam mechanism for operating said device, and means controlled by the speed of the car for effecting the-operation of both of the said operating mechanisms.

22. The combination with an elevator, of a car and counterweight a safety device carried upon the car, a safety device carried upon the counterweight, a running rope connecting said safety devices, and means on one of the said devices for driving said rope arranged that upon the fracture in the connection between the car and counterweight the running rope is operated by the counterweight to apply thecar safety device, the operation of which co-acts with the said rope to actuate the safety device on the counterweight, substantially'as described.

23..Ihe combination of an elevator car, a counterweight connected to the car, safety clamps on said car and counterweight, a running cable connected to and arranged to actuate said safety clamps, and means for placing a tension on said running cable to actuate the safety clamps with a predetermined pressure when-the tension on the suspension cable is varied beyond predetermined. limits.

24. The combination with an elevator car, of a counterweight connected. with the car, safety clamps carried on the car and counterweight, electrical and mechanical means for actuating said clamps, and automatic means for controlling both said electrical and mechanical means.

- 25.- The combination with an elevator car,

of safety devices carried on the car, electromagnetic apparatus for maintaining said devices in normal and inactive position, and automatic and manual means for controlling a circuit to said electro-magnetic apparatus,

and a cam controlled by the speed of the car for effecting the operation of the said safety devices independently of the said electro-magnetic apparatus.

In testimony whereof, we have signed our names to this specification in the presence W. D. BALDWIN. Witnesses:

THos. WV. LOG N, M. M. RIoKAnD. GRIFFITH JOHN. Witnesses:

C. BLINN,

C. NIENnoRFF.

lot