US 266107 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
(No Model.) 2 Sheets-Sheet 1.
R. M. CURTISS.
BLBGTRIG-SAPBTYYDEVIGB POR BLEVATORS. N0.266,107. Patented Oct. -17, 1882.
n. PETERS, Pmnnimogmvm. wnnmlxw. uA c.
. 2 Sheets-Sheet; 2Q
Patented Oct. 17. 1882.
R. M. CURTISS. ELECTRIC SAFETY DEVICE ECR ELEVATCRS. No. 266,107.
. Y ja'vemww M Q5,
'III Il UNITED STATES PATENT OFFICE.
ROBERT M. CURTISS, OF BROOKLYN, NEV YORK.
ELECTRIC SAFETY DEVICE FOR ELEVATORS.
SPECIFICATION forming part of Letters Patent No. 266,107, dated October 17, 1882. v
.To all whom it may concern:
Be it known that I, RoBERT M. CURTISS, of Brooklyn, Kings county, New York, have invented certain new and useful Improvements in Safety Devices for Elevators or Hoists, of which the following is a specification.
My invention relates to safety appliances connected with the movable car or cage of elevators and with the hoisting machinery operating it, whereby the safety-catches of the car will be released against the guides to uphold the car in case the hoisting-cable or any part of the hoisting machinery should become strained or broken, or in case the cable should become vslacked by the jamming of the car during the descending movement, even though no break or injury may have occurred in the machinery.
In a former patent issued to nie June 3,1879, No. 216,024, I employed an electric circuit passing through the cable and including an electro-magnetic detent in the car, which controlled the safetycatches, so arranged that on the breaking or straining of the cable the electric circuit would become broken, the magnetic detent relaxed, and the catches thereby instantly released to uphold the car. My present invention embodies this system, and is an improvement on my former patent. In my present improvement I extend a frangible electric conductor through the parts of the hoisting engine or machinery which are subjected to the working strain, and this conductor may also be continued through the hoisting-cable to the magnetic detent which controls the safety-catches, the conductor being of course arranged in a normallyclosed circuit constantly energized by a battery or other electric source, so that if any part of the hoisting apparatus becomes strained or broken-such as thecable or thepistomcylinder,shafts,sheaves, or bear ings of the hoistingengine-the frangible conductor which traverses these parts will become simultaneouslybroken, thus instantly which the car is suspended passes loosely through a socket in the hanger on top of the car, and a collar or shoulder fixed to the end of the cable seats against the under side of the socket, and thus suspends the car, and the electrical circuit is so arranged as to pass through the contact-faces of said collar and socket, so that in case the cable should ever become slacked during the descending movement by the jamming of the car in the guides these contact-faces will become relaxed or separated, thereby breaking the electric circuit and releasing the catches so as to safely sustain the car, and thus prevent the possibility of its becoming released and plunging down the shaft during the slack in the cable, as has frequently occurred heretofore with great damage.
My invention therefore consists mainly in the features here outlined, and also embodies several minor features in the special construction and arrangement of parts, as hereinafter fully set forth.
1n the drawings, Figure 1 presents a sectional elevation of an ordinary elevating apparatus, including the car, hoisting-en gine, &c., provided with my safety appliances. In this ligure the lioisting-engine is presumed to be ot' the hydraulic kind, arranged horizontally at the base ofthe shaft, the piston of the engine being arranged to operate a series of movable sheaves of a compound pulley, over which the cable passes in loops and extends to the car in the well-known manner, which it is unneeessary to describe in detail. Any other kind of hoisting-engine, however, may of course be employed. Fig. 2 is an enlarged detail view of the top of the car to which the cable connects, and which is provided with the suspensory electric contacts, which separate on the slacking of the cable, and which also carries the safety catches or pawls to engage with the guides, and the electro-magnetic deten't which holds them out otengagement while the circuit is closed and releases them when the circuit is broken. Fig. 3 is a detail of the suspensory contacts by which the cable connects with the car, showing the contacts separated, as occurs when the cable slacks. Fig. Ll. is a detail of the safety-catches in plan view. Fig. 5 presents a sectional elevation of a vertical ICO form ot' hoisting-engine, showing my safety electric circuit applied thereto in a somewhat different manner from Fig. 1, the car being omitted in this view. Fig. Gis a plan view of the under side of the car in Fig. 1, showing the arrangement of'saf'ety-catches and electromagnetic detent thereon. Fig. 7 is a similar view with the mechanism slightly modified. Fig. S is a perspective view of an ordinary hoisting-drum ot' a winding-engine, showing my safety electric circuit applied to the shaft and cables thereof.
Referring to Figs. 1, 2, and 6, l have shown the car as provided with safety-catches a a b b, of ordinary form, respectively at the top and bottom, which, when released, will engage with the usual ratchcts, c, on the guides d to sustain the car, but ofcourse either the top or bottom set of catches may be used alone, it' preferred.
In Fig. 1, e indicates a battery or other suitable source ot' electricity, one pole of which connects by the wire f to a conducting-strip, f', which extends along the cross-head guides of the hoisting-engine, and is insulated therefrom. A brush,g, which is carried bythe crosshead or piston-rod of the engine, bears on this conductor, and from this brush an insulated wire, g', extends through the piston-rod into the piston-head, being laid in a suitable bore or groove therein, and returning similarly through the rod, as shown by the dotted line, connects to a second brush, h, which is carried by the cross-head and bears upon a second insulated conductor-strip, t,parallel with the other one. From the conductor-strip h a wire, It, extends and passes around the journal-box ofthe ixed sheaves of the engine, and thence connects to the fixed end of the hoisting-cable t'. The circuit thence continues through the hoisting-cable, either directly through the mass of the cable or through an insulated wire embodied therein, and the current thus Hows toward the top ot' the car, as indicated by the arrows. Now, the' suspending or car end of the cable passes loosely through a socket, j', in the suspending loop or bail j, which rises from the top of the car, and the extremity ot' the cable is tixed in the holder or collar lc, which seats against the under side of the socket of the bail j, so that the car is thus suspended by the contact of the collar lc with the base of the socket j. Now, these suspcnsory contacting faces' are arranged in the electric circuit, for, as shown in Figs. l and 2, the current, in passing from the collar on the end of the cable, passes through the contacting face on4 the base ot' the socket, and a continuing circuitwire, l, extends from this face, and, descending to the bottom ofthe car, as seen in Fig. 1, connects with the end of the coils ot' an electromagnet, m', on the bottom of the car, as seen best in Fig. 6. From the opposite end of these magnet-coils the circuit is continued by a wire, l', up through the opposite side of the car, as seen in Fig. l, and connects with one end of a second electro-magnet, m, arranged on the top of the car, (shown also in Fig. 2,) and from the opposite end of this magnet a Wire, Z, leads to a brush, n, on the top of the car, which brush bears on a conducting-strip, n', which extends up along the guides d, and by which the current returns to the opposite pole of the battery by the wire n, which is connected to the base ot' the strip n', thereby completing the circuit.
Now the upper safety-catch or pawl-spring, a, is tlexed and held out ot' engagement, as shown best in Fig. 2, by the winding cfa cord, o', around the middle of a small winding or setting drum, 0, Figs. 2 and 4, which drum is held stationary by the grasp ot' double brakebands o, which are tightened by the depression ofthe lever q. When the lever q is thus depressed it is there held by a detent-hook on an elbow-lever, p, which forms the armature, or is connected with the armature, of the magnet m in a manner similar to what is shown in my former patent. It will hence be seen that lwhile the magnet is energized by a closed circuit its attraction will hold the parts in the set position shown, thereby holding the safety-catches out of engagement; but if the circuit becomes broken the magnet will become inactive, and thus release the parts and allow the catches to spring into engagement. In a similar manner the catches or bolts h b on the under side ofthe car (see Fig. 6) are held out ot' engagement against the stress of springs b b by the grasp of a forked lever, b, which embraces collars on the meeting ends ot' the bolts, and this forked lever is held in its engaging position by the armature -detent p, which is retained by the attraction ofthe magnet m', when in a closed circuit, in the same manner as that just described, so that on the breaking ot' the circuit the bolts b b will be released to engage with the guides, as will be readily understood.
It will therefore be seen that by my invention the entire elevating apparatus is, so to speak, enveloped in an electric safety web or circuit, which traverses all parts or most ot' the parts which are subjected to the working strain and wear, so that in the event ofany of these parts breaking-for instance, if the piston -head should become separated from the rod or the rod severed, the cross-headdetached or broken, the shaft or journal-boxes ot' the sheaves severed, or the frame-work of the engine fractured, or the cable rent-this electric circuit will become simultaneously broken and the safety-catches instantaneously released, and the car thus held safely in the guides, before any damage could result to the occupants by such break or injury.A This invention hence presents a notable safety device, for it has ot'ten happened that while the cable has remained uninjured some part ot' the hoistingengine has broken, and thus allowed the car to fall, while its cable and safety-catches remained unimpaired, for the common safetycatches act only by a great relaxation or breaking ot' the cable, and where there is suilicicnt ICO IIO
strain oii the cable to keep the safety-catches out, yet not sufficient to stop or retard the car, as would be the case with a break in the engine, the safety-catch will not act and the car will fall disastroiisly, as has occurred on several occasions. This, however, is completely prevented by my improvement, for by its means a break in any working part of the hoistingengine, as well as in the cable, will release the clutches and sustain the car with electrical quickness and certainty.
It will be noted on reference to Fie'. 1 that the circuit also passes up through each side of the car from the bottom, and that the circuit controls safety-catches both on the top and bottom of the car. Hence, it' the car should break apart in any manner, as not uncommonly happens, say if the top part should become torn away from the bottom, or vice versa, the circiiit-wires will in either case become broken and the saiety-catches'on the bottom ofthe car instantly released, thus safely sustaining the door of the car and the passengers which may be in the car. Now, on the other hand, although no pait of the hoisting appa.- ratns should break, assume that during the descending movement the car should become jammed in the guides from any cause,the cable would then of course continue to be paid out by the retiirn-stroke of the engine, and .thus form an extensive slack, and it' the car should during this slack become again loosened in the guides it would suddenly plunge downward or fall, and thus be likely to do great damage. It will be seen, however, that my invention completely provides against the chance of this accident, for if any slack forms in the cable during the descent ofthe car the collar 7c on the end of the cable (see Figs. 2 and 3) will separate or recede from the under side of the socketj', and thus break the electric circuit, and thereby release the catches and preventthecarf'rom falling,thusprovidingagainst accidents under almost all circumstances.
In Fig. 2 the suspensory contacts are shown in contact, but are represented as separated in Fig. 3 by the formation ot' slack in the cable. In order to insure the certain separation ot' these contacts on the formation of slack, a strong spring, lo, fixed at one endto the cable and at the other end to the suspending-bailj, tends constantly to pull the collar-ed end ofthe cable away from the socketj, which it will do as soon as the cable becomes relieved ot' the weight of the car. The weight of the slack cable would of course ot' itself tend to separate the contacts; but the spring k assists this action and renders it more certain, as will be understood.
It may be noted that, if desired, the downward motion of the collar on the end of the cable when the. cable becomes slacked might be arranged to close an electric circuit normally open, which when so closed would energize an electro-magnet to release the safetycatches, this being simply a reverse modication of that shown but I prefer the close-circuit arrangement sct forth.
In Fig. l the cable may, if desired, be omitted from the electric circuit and the circuit completed through the conductor-strips on the guides; or, again, the conductor-strips on the guides may be dispensed with, and the circuit may then be advanced and returned through the cable by advancing and returning wires insulated from each other, as shown in my former patent, and alsoillustrated in Figs. 3 and 5 of the present drawings. In Fig. 5 the current iiows from one pole of the battery to a conducting-rod, r,on which slides an arm which projects from the cross-head, through which arm the current passes and descends through one piston-rod, thence crosses through or above the piston-head, rises through the second piston-rod, thence passes through the shaft of the movable sheave to a second brush carried by asecond arm on the cross-head, and bearing on a second conductingrod, r', and from this rod the current tiows through an insulated wire in the cable, passes through the magnet m or m', or both, and returns through another wire in the cable, as indicated by arrows. which return wire, as indicated by s in Fig. 5, is extended from the hxed end of the cable, passes across the upper head of the enginecylinder, down along one side of the cylinder, across the bottom head, up the opposite side of the cylinder, and thence connects to the opposite pole ot' the battery, thus completing the circuit. The circuit-wires should ofcourse be covered or insulated throughouttheircoiirse, and insulation should be introduced wherever necessary to insure the passage of the current, as described and indicated. rlhe circuit is preferably continued through the piston-rods by means of insulated wires laid in grooves cut therein and covered up flush with the cylindrical surface of the rods. The circuit wires or conductors which traverse the parts of the car and hoisting machinery which are liable to become broken or fractured by the working strain should be stretched upon and fastened along the parts of the car or machinery along the couise of the circuit, and while sufficiently large to convey the necessary current these wires should be sufficiently fragile so as to become easily broken by any stretch. stra-in, or fracture in the parts of the car or machine on which they are fastened. By this means l insure the breaking of the circuit and the releasing ofthe safety-catches, as described, when any dangerous stretch, strain, or fracture occurs in the car or machinery, although no actual break may have yet occurred, thus forming a most vigilant and valuable guard for the prevention of damage to the car or'its contents.
In Fig. l I have represented an incandescent electric lamp, t, in the safety-circuit to light the car, and this may be extinguished and thrown out of circuit, when desired, by a switch, which will thus cut the lamp ont of ac- ICO IOS
tion without breaking the safety-circuit. The lamp, however, is preferably placed in a separate circuit. which can be advantageously coinpleted by brushes carried by the car bearing on conducting-strips on the guides, similar to what is shown atn a in Fig. l.
Fig. 7 shows a slight modification of the mechanism ot' Fig. 6 on the under side of the car. In this case the safety-bolts b b connect by clamps to crank-pins on a brake-disk, o, on which a brake-baud is tightened by a lever, q, and held by the armature-detent, saine as in Fig. 2.
Fig. 8 shows one way of applying my electric safety-circuit to an elevator which operates the car from a winding-drum. In this case two parallel cables are supposed to be used. rIhe two poles of the battery connect with two brushes, which bear upon insulated conducting-rings u a on the projecting end of the drum-shaft. Insulated wires extend through the shaft from the respective rings, and connect respectively with the fixed ends of the two cables, the circuit passing thence through a wire in one cable, through the detent-magnets on the car, as before described, and thence returning through t-he wire in the other cable, as indicated by the arrows.
I do not of course confine myself to the precise mechanical constructions shown in which my invention is embodied, as the mechanical form of the parts might be varied considerably without departing from the principle. I would also remark that I prefer to have the magnets which control the detents and safety-catches arranged upon the car, as shown; vet the magnets might be arranged apart from the car, but operatively connected with the catches on the car, if desired.
It will be seen that the conductor-stripsf h and brushes g h in Fig. l form an extensible or movable conductor between the portion of the circuit in the movable part of the machine a-nd the fixed parts. Any other form of extensible conductor might of course be used between these parts-for instance, a spiral spring or a toggle-loop of wire whose slack would be taken up at the middle by a pulley-weight.
Instead ofthe conductors being iu the form of continuous or solid wires traversing the parts of the car or motor, which are liable to become broken, the conductor may be in the form of sectional strips, bearing on each other and adapted to become separated, so as to break the circuit when the parts traversed become broken; but a continuons fragile conductor is preferable.
A close hood or cover, i/is placed over the detent mechanism at the top ofthe car to proteetit from dust or injury. The mechanism at the bottom of the car may be similarly covered.
What I claim isl. The combination, with a hoisting or elevating apparatus, of a frangible or separable electric conductor traversing portions of the hoisting machine or motor which are subjected to the working strain or wear, and arranged in a closed electric circuit including an electromagnetic detent which controls safetycatches arranged to uphold the car, whereby the breaking of the parts of the motor so traversed will break the electric circuit, and thereby relax the magnetic detent and release the safety-catches to uphold the oar, substantially as herein set forth.
2. In an elevating apparatus, the combination, with an engine constructed with a working cylinder and a pistou operatively connected with the car through the intervention ot'a pulley and cable, or their equivalent, of a fran gible or separable electrical conductor traversing the piston rod or other working parts of the engine, a closed electric circuit in which said conductor is included, an electro-magnet forming part of said circuit and arranged to control Vsafety-catches to uphold the car, so arranged that on the breaking ofthe electric circuit the said magnetacts to release the catches to sustain the car, substantially as herein shown and described.
3. In a hoisting apparatus, the combination, with uthe car and the hoisting-cable or equivalent t'rom which the car is suspended, and with safety catches to uphold the car, of an electric circuit passing through the contacts by which the car is suspended from the cable, and an electro-magnet in said circuit arranged to control the safety-catches, whereby the slacking` of the cable will separate said contacts, break the circuit, and release the safetycatches, substantially as herein set forth.
4. In an elevator, the combination, with the car and the hoisting-cable from which the same is suspended, and with safety-catches arranged to uphold the car when released, ot' an electricjcireuit and a magnet in said circuit controlling the safety-catches, with the end of the cable arranged loosely in the suspendin g-socket on the car and capable of play therein when slacked, and so connected with said electric circuit that the relaxation ormovemcnt of the cable end in the suspending-socket will make or break said circuit, and thereby operate said magnet so as to release the catches and sustain the car, substantially as herein set forth.
5. The combination, with an elevator car or platform provided with safety catches arranged to uphold the car when released, of a frangible or separable electric conductor traversing the car or portions of the car, and arranged iu a closed electric circuit, with an electro-magnet in said circuit arranged to control said satety-catches, whereby the breakin g or straining ofthe car will break thc electric circuit and release the safety-catches, and thereby hold or sustain the broken car, substantially as herein set forth.
ROBERT M. CURTISS.
JNO. E. GAVIN, GHAs. M. HIGGINS.