US1134753A

US1134753A - Appliance for elevator safety devices.

Info

Publication number: US1134753A
Application number: US66193111A
Authority: US
Inventors: David L Lindquist
Original assignee: Otis Elevator Co
Current assignee: Otis Elevator Co
Priority date: 1911-11-23
Filing date: 1911-11-23
Publication date: 1915-04-06
Anticipated expiration: 1932-04-06

Description

D. L. LINDQUIST.

APPLIANCE FOR ELEVATOR SAFETY DEVICES.`

APPLICATION FILED Nov. 23. I9II.

1,1 3%753, Patented Apr. 6, 1915.

Il@- gg 3D w 5v e Q f THE NcRRls PETERS E0.A PHLETQLITHO.4 WASHINGTON. n

DAVID L. LINDQUIST, 0F YONKERS, NEW YORK, ASSIGrNOR T0 OTIS ELEVATOR,

COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OIE NEW JERSEY.

APPLIANCE FOR ELEVATOR SAFETY DEVICES.

Application filed November 23, 1911. Serial No. 861,931.v

To all whom imag concern Be it known that I, DAVID L, LINDQUIs'r, a subject of the King of Sweden, residing at Yonkers, in the county of Westchester and State of New York, have invented a new and useful Improvement in Appliances for Elevator' Safety Devices, of which the following is a specification. p

My invention relates to elevator safety devices and has for one of'its objects lthe provision of a simple and efficient friction hitch or clamping appliance coperating with the governor cable of anelevator and adapted primarily to prevent an excessive strain from being placed upon the safety cables and co-acting parts when the safety device is called into action. i

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

The elevator safety device in general use at the present time, an example of which is known as the Ellithorpe safety has proven to be very satisfactory for elevators of .moderate speed and rise, but at the present day when it is nothing unusual for an elevator car to travel to a great height at a normal speed of over 600 feet per minute a condition arises in connection with the operation of the safety device which is of serious import and which must be met in order that the safetyv device may be infallible in its operation regardless of the speed and distance of travel of the elevato-r car. The above-mentioned type of safety device comprises a cable drum located under the floor of the car and adapted when actuated to move outwardly a pair of wedges or toggle levers carried upon the ends of right and left hand threaded rods. These wedges or toggle levers effect the operation of corresponding clamp jaws which engage the guide rails of the elevator and the retarding action set up by the frictional engagement of the jaws on theA rails brings the elevator car to rest. The rotation of the safety drum is effected by means of a cable coiled about the drum and connected to another cable which runs with the car during the normal operation thereof and which is substantially locked against movement by means of a speed governor when Specification of Letters Patent.

PatentedApr. 6, 1915.-

the car attains a predetermined speed iny eX- f cess of the' normal. Asfsoon as the clamps controlledby the governor grasp the cable to apply the safetydevice this cable is `retarded and no longer runs at the same speed as that of the car and the relative movement of the carv with respect to the cable causes the safety drum to'be rotated and the gripping clamps will be set up on the guide railsl and the car retarded and finally stopped. During the interval of time required to set the clamping jaws on the guide rails the governor cable will in most cases come to rest or at least have its speed substantially reduced although the car is still traveling at a high speed, After the jaws are once set up onthe guides it is seen that they can move no further andthe safety drum willl cease to rotate consequently the drum cable cannot further be pulled 0E. The velocity of the car isnow suddenly imparted tothe governor cable, which as before pointed out has been by this time substantially brought to rest by the iclamps controlled by the governor, and it is clearly seen that this velocity which may be and frequently is over` limits whenthe speed of the car is not tool high and when the inertia of the governor cable, or what amounts to practically the same thing, the height of car travel, is not too great, it is readily seen that some provision must be made to take care of this strain where thecar travels to a considerable height at high speed. Where the car travel is in the neighborhood of 600 ft. at a normal'car speed of GOO ft. per minute, the governor cable weighs approximately 7:20 pounds. Now at the instant of operation of the safety the car may reach a speed of 800 feet'or more per minute, and when it is considered that the governor cable weighing 720 pounds must be accelerated instantly from Zero to 800 ft. per minute which condition is further augmented by the frictional engagement of the governor clamps on the governor cable which amounts to approximately 800 pounds retarding force in addition to the inertia of the cable itself, it is readily seen that the strain suddenly placed upon the governor cable is of great magnitude and the same has been the means of causing the cable to break. My invention is for the purpose of overcoming this great strain and protecting the cables and other apparatus under all conditions met in practice.

Broadly speaking my invention comprises an adjustable spring pressed friction hitch or cable clamp which is introduced between the end of the cable wound upon the safety drum and the governor cable which permits of a relative shipping movement therebetween under excessive strain thereby relieving the cables associated with the safety device from all danger of breakage.

My invention is shown on the drawing accompanying this specification in whichi Figure 1 represents in elevation an elevator system embodying my invention; Fig. 2 is a sectional view of my friction cable clamp; Fig. 3 is a side view in part section of Fig. 2; Fig. et is a sectional plan view of Fig. 2 taken on the broken line a--a,' Fig. 5 is a plan view in part section of a supporting clamp used to attach the cable clamp shown in Fig. 2 to the car; Fig. G is a diagrammatic plan view in section of a safety device used for stopping the car in case of excess speed.

Like characters of reference denote similar parts in all the figures.

Referring to the drawing, the elevator car is designated by C and is suspended from the hoisting cables 1 which lead up over the overhead sheaves 2-2 carried in brackets secured to the beams 3 and which lead to any desired power driven hoisting mechanism such as an electric or other motor. To the bottom of the car is secured what is generally known as the safety plank l which carries the rail gripping jaws and their operating connections shown in detail in Fig. 6. rlhe safety drum is designated by the numeral 5 and has wound upon it a cable 6 which is guided by a pair of sheaves 7 and is connected by means of a leaded clevis 8 to the clamping device 9. rEhe latter is yieldingly secured to the car by means of a friction clamp 11 which is illustrated in detail in Fig. 5. The endless governor rope 10 leads up and over the governor sheave 1Q. located at the top of the hatchway and passes around a weighted sheave 13 located at the bottom of the hatchway. The weighted sheave 13 is for the purpose of maintaining the governor rope under a tension and its movement in an upward direction is limited by means of the guides 14. The governor shown is the well known Otis type of governor and operates upon excessive speed to raise the rod 15 thereby rotating the geared clutch members 1t3-16 so that they clamp the governor cable 10 and tend to bring it to rest. lt should be noted that the clutch members 16-16 are not intended to jam the cable 10 so that it is positively held against movement but they are arranged so as to engage and clamp the cable 10 with a predetermined pressure which is regulated by the tension placed upon the spring 17 which bears against one of the clutch members 16, said member being arranged so that it has a small bodily movement away from the opposite clutch member under pressure of the governor cable.

l will now give a brief description of the Ellithorpe safety device shown in Fig, G. The cable drum 5 is threaded upon a pair of oppositely threaded rods 18-18 which are carried by the supports 19-19 secured to and forming a part of the safety plank il. rfhe outer ends of these rods are connected by toggle levers 20-20' to corresponding clamping jaws S21-21 which normally move freely over the guide rails 2x2- i2 when the elevator is in its normal running condition. lf by reason of excessive car speed the drum 5 be rotated, the threaded rods 18-18 are screwed outwardly thereby causing the gripping jaws to be closed upon the guide rails and thus act as a powerful brake to eifect the retardation and iinal stopping of the car. The drum is rotated by means of the cable 6 which heretofore was always rigidly connected to the governor cable 10 so that as soon as the governor acts and the cable 10 is substantially held against movement the continued movement of the car causes the cable 6 to be unwound from the safety drum thereby rotating the latter and effecting the application of the safety clamps to the guide rails. As l have already pointed out the danger of having a rigid connection between the safety drum cables and the governor cable, I will now describe my invention as shown in detail in Figs. 2, 3, a and 5, which will obviate the danger. The device comprises a metal sliding hitch 23 of substantially cylindrical form the upper part of which is hollowed out and contains a conical split bushing 26. Surrounding this bushing and inverted with respect thereto is another conical bushing 27 which is not split. A tension spring 28 is adapted to bear against the top of the bushing 27 and against a hollow plug 30 which is threaded into the upper part 24 of the hitch 9 and which may be screwed down against the spring QS with any desired amount of pressure and locked in place by means of the lock nut 32. The interior of the hollow plug 30 is screw threaded and contains a sleeve 29 which is also threaded and which is screwed down hard against the conical bushing 26 and locked in position by means of the lock nut 3l.

The purpose of the sleeve 29 is to prevent the conical bushing26 from being moved upwardly Vuponthe governor cable and Y jamming the latter against'movement therethrough. The governor cable passes loosely through the sleeve 29 but is gripped by the split bushing 26 with a power depending upon the tension placed upon the spring 28. It may be observed that the spring forces the bushing 27 over the split bushing26 and since these bushings are conical in formthe pressure exerted by the spring tends to contact the split bushing and cause the latter to grasp the cable. The governor cable after leaving the bushing 26 continues through a flared orifice 25 and is deflected from a vertical position by a roller 33 carried upon a stud 3a which passes through the hitch member and is riveted at either end. The governor cable passes over another roller 33 mounted similar to the first roller and is againdeected so as tov pass through a flared opening37 at the lower end 36 of the hitch member. Intermediate the rollers.33*33 a clevis 8 is secured by means of a vrivet 35 each end of which is rounded over so as to form a pair of button heads 38-38. In order that the governor cable maytravel with the car it is necessary to. provide a connection therebetween, furthermore this connection must be yielding in its nature so that the governor cable may be disconnected from the car when the governor operates otherwise there can be no relative movement between the governor cable and the car and the safety drum would not be rotated. This yielding connection I have shown in detail in -F ig. 5 and the same comprises a pair of hinged members 39-39 pivoted at 40 to a bracket 41 which is rigidly secured to the oar at any suitable place thereon. Each of the hinged members 39 is provided with a spherical recess 42 which normally contains the button headed ends of the rivet 35 and the hinged members are urged toward each other by means of a tension spring 43 whose tension may be regulated to the required amount by means of the adjusting nuts 4:4. This arrangement forms a simple and practical means for effectinga yieldable connection between the car and friction hitch 9 and the tension of the spring 43 may be regulated so as to vary the pullnecessary to separate the connection between the car and the friction hitch. y It will be observed that the rollers 33 33 serve a double function, that is they not only tend to introduce a frictional retardation between' the hitch 9, and the governor cable owing tothe double deflection of the latter but they also serve to'VV guide the governor cable awayfrom the clevis 8 so that there will be no interference therebetween when the safety device operates and the hitch 9 slides along thecable. j

In view of the foregoing description, the operation of my invention is almost, if not quite, self explanatory. It will be readily seen that when the governor rotates at a speed in excess of what. it was set for, the clutch members ofthe governor will grasp the governor cable and pull it loose from the yielding connection on the car. Aj pull is now exerted upon the cable 6 land the safety drum will be rrotated thereby until the grippingjaws have moved up against the rails whereupon the drum will cease to rotate. By this time the governor has brought the governor cable substantially torest and since the car is still traveling at high speed a sudden jerk is given to the governor cable, this jerk beingresisted by reason of the inertia of the governor cable which is now'at -rest and'by reason of the grip of the governor clutch von the cable. It is at once seen that this jerk may beof such magnitude as to break the governor cable or the safety cable or both and itnow becomes apparent whereiu'the great practical value of myfrictionhitch comes in.. As soon as this jerk comes on the cable the frictionhitch 9 permits of a relative movement or slipping between thesafety drum cable and the governor cable and since this friction may be adjusted to any desired amounty the strain placed upon the `cables may be regulated at will and all danger of breakage of cables obviated without diminishingthe efliciency of the car brake or gripping j awsv in the least or lessening their retarding power.

My invention'maybe Vconsidered in one sense as a. buifer device or shock absorber since'it not only relieves the safety cables and all the apparatus associated therewith fromexcessive strains and shocks under all conditions of operation, but at thesame time` there is v-no danger ,of having the gripping jaws of the safety device set up too hard on the guide rails which -w'ould tend to effect an excessive retardation of the 'car and cause the same to be brought up too suddenly which 'of course is most undesirable. It is readily seen that `the retardation Yof the car due to the action of the clamping jaws on the guide rails may be varied by adjusting the tension of the spring 28 of the friction hitch. ,For example `we will assume that this tension is of such an amount that thepull required to slide the hitch along the` governor cable is about 700 pounds, it havingl been demonstrated in practice that a pullfof 700 pounds on the safety drum cable is ample to effect ay satisfactory Stop of the elevator car under average conditions of load and speed. If now the safety device operates, it is seen that iio iso

after the safety drumhas been rotated to the extent of its movement, and the clamping jaws have been set up hard on the rails any increase in pull on the safety drum cable will act to increase the grip of the clamping jaws von the guide rail until a maximum pull of substantially .700 pounds is placedupon the drum cable and this pull cannot exceed 700 pounds byany appreciable amount since any tendency to increase it is counteracted by reason of the friction hitch sliding upon the governor cable.

I have shown and described myiinvention in connection with an elevator safety device of well known type for they reason that it is particularly adapted to such use and also for use with elevator safety devices in general, but it will be observed .that the same may be used without changing its principle of operation or evenits structure for many other purposes wherever it is desirable to form an adjustable yielding connection between a plurality of parts whether the same be cables, or other flexible members.

` What I claim as new and desire to have protected by Letters Patent of the United States `is l. The combination with an elevator safety device, of a governor cable, asafety actuating cable, and a yielding connection therebetween.

"2. vThe combination with anelevator safety device, of a governor cable, a safety actuatingk cable, and an adjustable yielding connection therebetween.

3. r)The combination with an elevator safety device, of aL governor cable, a hitch yieldingly secured uponsaid cable, and a safety actuating :cable fastened at one end to said hitch.

if. The combination with an elevator-safety device, of gripping jaws adaptedto engage the guide rails, a drum arranged to effect-the operation ofsaid jaws, a cablewound about said drum, means for effecting a pull on said cable, and a yielding connection between said cable and means.

5. yIn an elevator, the combination of a car, a safety device carried uponthe car, an actuating cable associated with said safety device, a governor cable'connected to saidA actuating cable, and means for permitting a relative motionv between said cables.

6.' In an elevator the combination of a car, a safety device carried by the car, means for effecting theoperation of said safety device, a governor and governor cable, a clutch operated by the governor and adapted yieldingly to engage the governor cable upon excessive speed of the car, a friction hitch secured to .said governor cable, and a connection between said friction hitch andL said safety device operating means.

`7. The combination with an elevator safety device, of means for applying said device, a governor cable, a friction hitch between said applying means and said cable, and spring pressed means for regulating the traction of said hitch to any predetermined amount.

8. In anelevator safety device, the combination of an actuating cable, a governor cable,a friction .hitch arranged on the governor` cable,and secured to said actuating cable, said'hitch comprising an expanding bushing surrounding the governor cable, and means for effecting a contraction of said expanding bushing.

9. Inan elevator safety device, the combination of an actuating cable, a governor cable, a friction hitch arranged on the governor cable and secured to said actuating cable, said hitch comprising an expanding bushing .surrounding the governor cable, means'for effecting a contraction of said bushing, and means for controlling the power of said last named means.

'10. In an elevator, the combination of a safety device, a governor cable, a friction hitch carried by said cable, said hitch comprising an expansible bushing in contact with said cable, an additional bushing surrounding said expansible bushing and arranged to effect a. contraction thereof, a spring bearing against said additional bushing, means for'regula-ting the tension of said spring, and an operative connection between said safety device and said hitch.

1l. In an elevator, the combination of a safety device, a. governor cable, a hitch carried'upon said cable, spring pressed means for causing said hitch frictionally to engage saidv cable, vrmeans for effecting a deflection in said cable to increase the frictional engagement of said hitch and cable, and an operative connection between said hitch and said safety device.

12. The combination with an elevator car, of asafety device for effecting a retardation of said car upon excessive speed, and frictional means for regulating said retardation to any predetermined amount.

13.' The combination with an elevator, of gripping Yjaws adapted to engage the guide rails, a safety'drum, operating means between the safety drum and gripping jaws, a

cable connected to the drum and arranged to effect the operation of said drum, and means for effecting a' predetermined pull on said cable regardless of the load and speed of the car.

14. In an elevator, the combination of a car, a retarding device carried upon the car, a governor cable normally running with the car, a drum, a drum cable connected to the retarding device; automatic means for effecting a movement of said governor cable relative to that of the car to effect the application of said retarding device, and means associated with said governor cable for limiting the amount of retardation of said device.

`15.'In an elevator, thefcombination of a 130 car and guide rails therefor, a safety device comprising clamping jaws adapted to engage the guide rails, automatic means for effecting the operation of said jaws,v and rictional means for regulating the gripping power of said jaws to any predetermined amount.

In testimony whereof, I have signed my name to this specification in the presence of two subscribing witnesses.

DAVID L. LINDQUIST.

Witnesses:

W. 'I-I. BRADY, EDGAR W. SMITH.

C'opies of thisipatent may be obtained for ve cents each, by addressing the Commissioner of Patents,

Washington, D. C.