US2025241A - Safety appliance for elevators - Google Patents

Description

Dec. 24, 1935. R. P. HOOKS I SAFETY APPLIANCE FOR ELEVATORS Filed Feb. 5, 1935 '2 Sheets-Sheet 1 grvuQ/WM R. P Hooks,

Dec. 24, 1935.

R. P. HOOKS Filed Feb. 6, 1955,

' awe/whom R. P. HO0I S,

Patented Dec. 24, 1935 UNITED STATES PATENT OFFICE SAFETY APPLIANCE FOR ELEVATORS Application February 6, 1935, Serial No. 5,278

12 Claims.

This invention relates to improvements in elevators, especially to safety devices for elevators, and its objects are as follows:

First, to provide multiple brakes and catch devices respectively for exercising a brake action against the rails of an elevator car and for moving against and gripping the sides of the elevator well.

Second, to provide a linkage by which the brakes and catch devices are positively connected so that they will work in unison immediately upon the breaking of the cable, or upon a slackening of the cable as, for example, when the operator at the hoist pays out cable at a rate in excess of the lowering speed of the car and thereby sets up a condition which may become dangerous.

Third, to so coordinate the rail brakes and well side catch devices that the latter are depended upon for the greatest gripping force against the sides of the well, these catch devices being depended upon for the main sustaining function, thereby protecting the rails from becoming unduly scored and worn by the brakes.

Fourth, to provide the rack arm of each catch device with an eccentrically pivoted shoe which, because of its eccentricity, will turn outwardly an increasing extent when its contact with the adjacent side of the well once begins thereby to increasingly dig into the side of the well, the rack arm itself being simultaneously turnable into engagement with a detent on the car that will hold the arm to a given degree of extension so that it cannot come back as long as the weight of the car depends upon this and the other catch de-- vices.

Fifth, to actuate the suspension head and the foregoing linkage by separate springs of which the first springs are a little weaker than the latter springs, said first springs being solely intended to move the head independently of the car upon a cable breakage in order to release the linkage for its operation, the second springs then insuring the operation of the linkage to cause the multiple brakes and catch devices to work.

Sixth, to make the rack arms .which carry the catch devices, act as governors of the brakes, causing the brakes to grip the guide rails lightly in case the arms have only a short distance to go before the catch devices take hold of the well wall, and to grip the rails more heavily if said arms have a greater distance to go.

In the drawings:--

Figure 1 is a side elevation of an elevator car, particularly showing the multiple brakes and catch devices in their inoperative positions during the running condition of the car.

Figure 2 is a central vertical section of the same car, illustrating internal parts more in detail.

Figure 3 is a detail sectional view of the top 5 part of the car, showing how the suspension head has moved relatively to the car upon cable breakage.

Figure 4 is a front elevation of the car, the parts being in the same positions as in Figure 1. Figure 5 is a horizontal section taken on the line 5-5 of Figure 1.

Figure 6 is a horizontal section taken on the line 6t of Figure 2.

Figure 7 is a detail sectional view of the bottom part of the car, this view being read in connection with Figure 3 because of its illustration of the extension of the catch device upon a cable breakage.

The herein disclosed safetyappliance is primarily intended for mine elevator cars, but it is not confined to that use because it can be employed on other types of elevators. Also, the i1- lustration of the car in Figures 1 and a is not necessarily adhered to, because the car can be manufactured in any form, size and design without affecting the installation or working of the invention in the least.

Referring now to the drawings, the cable I is firmly attached at the car end to an eye 2 which is fixed at 3 to what is herein known as a suspension head 4. The eye 2 and head 4 can be made in one piece, but generally the two will be riveted or otherwise secured together. The head 4 consists of an upright, cross-sectionally non-circular bar which is capable of vertical motion with respect to the elevator car.

At its lower end it is shouldered at 5. The resulting reduced end 6 is inserted through a central hole in a saddle I. The end 5 can be threaded so that when a nut 8 is screwed home against the underside of the saddle the latter will be rigidly and permanently attached to the bar, so that the bar and saddle constitute one piece which serves as the suspension head. The extremities V of the saddle are curved downwardly, and the downward curvatures have slots 9.

A head bar l0 goes across the top of the elevator car. The car is generally designated H. The head bar has a central hole E2 to match the cross section of the suspension bar t, and it is in this hole that the suspension bar is movable relatively with respect to the car ll. Springs l3 (Fig. 4) have'their ends attached to points of connection on the two bars. These are contraction springs, and their tendency is to pull the suspension bar 4 downwardly. This tendency is prevented as long as the weight of the car ll hangs on the cable I, but when the cable breaks, or becomes unduly slack, the springs [3 will act to move the suspension bar 4 through the head bar l0, and move the saddle 1 downwardly toward the interior of the car.

The elevator car will be of any desired construction, as has been indicated before, but for the purpose of the present illustration it includes top plates I4, a floor structure I5, supporting angle irons l6, rail guides ll, braces l8 and plates IS. The top plates !4 are triangular. The ends of the head bar It! are secured to them in a spanning position (Fig. 4) near their apex (Fig. 2). The plates l9 come immediately below the top plates M. The plates H! are secured at 20. to flange parts 2| of the guides l1, and since the flange parts are secured to the top plates l4 at 22 it'follows that the two kinds of plates and the 'flange parts comprise an integral structure. This is also. true at the bottom because the flange parts are secured to, the floor structure at 23.

A pair of parallel trip shafts 24 is journaled at the top of the car ll, their ends going through the top plates i4 and the flan e. parts 2|. These provide a double bearing for the shafts. At their centers said shafts have studs 25 which extend upwardly through the slots 9 of the saddle 1. The studs taper slightly toward their free ends. They are cross-sectionally non-circular, but not necessarily so. They are held in a position to point upwardly (Fig. 2) by thebridge pieces 26 of the saddle 1, which bridge pieces define the lower ends of the slots 9, as long as the car ll remains suspended from the cable I. But when the cable. breaks, the suspension head 4. goes down, and the studs 25 to go with it so that they point in diverging directions; (Fig.7 3).. 7

On eachouter. end of the shafts 24' there is a brake arm 21 which extends from the brake presently described. Because of the fact that, each brake and each: catch device, and the linkage connecting the brakes and the. catch devices is identical ineach of the four instances, the description is confined to a single system for the present, but corresponding, reference characters are applied throughout to. corresponding parts.

Consider the safety appliance at. the right. The brake arm 21 has a heel 28 which is perpendicular to the top edge of; the arm, and when, the latter stands in the horizontal position (Fig. 1), as it does when the safety appliance is at rest, the heel 28 clears the rail 29, (Fig. 6) so that it does not rub against the rail. This heel is part of a brake 38, and the brake 30 is one of. the multiple brakes referred to before. This curves away eccentrically from the shaft 24. In other'words, the brake 30 is eccentric to its pivotal axis. Its face istoothed at 3!.

The free end of the arm 21 is pivoted to a rod 32 which reaches down and is pivoted to a crank 33. This crank is secured to one outer end of what is herein conveniently termed a catch shaft 34. The catch shaft has another crank 35 (Fig. 2). This crank has a rack arm 36 pivotally connected to it. The previously mentioned linkage comprises the rod 32, crank 33, catch shaft 34, crank 35 and rack arm 36.

Digressing for a moment from the previously adopted sin le description of one of the safety appliances, there is a pair of the catch shafts 34 in substantially identicalrelationship to the bottom of the car II as are the trip shafts 24 with respect to the top of the car. The shafts 34 are journaled on the floor structure, and they have double bearing in the floor structure and in the flange parts 2|, their ends protruding as in the instance of the shafts 24.

Now reverting to the single description: The arm 36 has a rack surface 31 on one side. The rack surface is on top. The rack arm goes through a slot 38 in a member 39 which is part of the floor structure l5. It also goes through a slot 40 in the angle iron IS. The top of that slot is formed into a heavy tooth or detent 4i, and in order that the detent may have sufiicient strength, the angle iron l6 may either be thickened along its top corner, or reinforced with an extra cross bar, in order to enable the detent to take the heavy strain which will be imposed upon it in stopping the car.

The rack 31 is intended to then engage the tooth 4| and prevent the rack arm 36 from slipping back through the slot 40. For the purpose of said engagement the arm 3.6 is vertically turnable on the pivot 42. which connects it with the crank 35... At its freeqand' outer end the rack arm 36. carries a catch device 43.. Its toothed face 44 is struck on a curve which is eccentric to the pivot 45 which connects the catch device and the arm- The arm has an outwardly slanting rest 46 which. is abutted by the heel 41 of the catch device when in its final position against the side of the elevator well 48 (Fig. 7).. The point of the catch device 43 digs in as shown, and it is this point which takes the main strain of supporting the car ll upon a cable breakage.

A spring 49 pulls down. upon the rod 32 so as to perpetually tend to turn the linkage 32-46 and engage the catch device 43 with: the wall 48. This tendency is prevented by thestud 25 and the saddle l of the suspension head as long as the car remains suspended from the cable. But when the cable breaks, the spring 49 is free to act. One end of it is anchored to the flange part 2|, or some other convenient. part of the car H. The other end of the spring is connected with a turnbuckle 50 which, in. turn, is connected to the rod 32. The purpose of the turnbuckle is to enable adjustment of the tension of the spring 49. The tension of thisspring is greater than the tension of a single one of the springs l3 (Fig. 4). The latter are merely intended to insure gravitation of the suspension headv upon a cable breakage. Upon the spring 49 (and its companions) rest the duty of moving the entire safety appliance into operative position.

The operation is readily understood. As long as the cable I- (Fig. 1) remains intact, the weight of the car II holds the parts in the positions in Figs. 1 and 2. The heels 28 of the brake arms 2'! clear the rails 29 on opposite sides of the car (Fig. 6). The catch devices 43 are in as far as they will go, virtually being housed by the floor structure 15. They are, far enough in to avoid any. possibility of contacting the wall of the well 48.

Assume that the cable I breaks. Gravity cannot be depended upon to move the suspension head 4 relatively to the car ll because the two parts, having the same momentum, might stay in the original position in Figure 2. The springs Ii; insure the relative movement; and that will be a downward movement of the suspension head 4 with respect to the car IL As the suspension head moves downwardly (Fig. 3) the bridge pieces 26 ofthesadd-le 1 recedefrom the studs 25.

Since the latter work under. thetension of the springs 49, which tension is constantly applied to the linkage 32-36, it follows that the studs 25 will go with the saddle. There is a unitary action of the trip and catch shafts 24, 34. The brake arms 21 will be turned downwardly (dotted lines, Fig. 3) and the catch devices will be projected into wall engaging positions (Fig. '7). The catch devices 43 must traverse a greater space before they can act than do the brakes 30.

These brakes, being of eccentric form, will immediately work against the rails 29, setting up a braking action, and the degree of braking action will depend on the amount of extension of the arms 36. The brakes 30 will be applied lightly if the arms 36 have only a short distance to go before the catch devices 43take hold, but will be applied heavily if the arms have a greater distance to go. But the braking action will not be to that extent as to excessively damage the rail surfaces. Before that can occur the curved faces of the catch devices 43 will have reached the wall When that happens there will be a simultaneous turning of the rack arms 36 and catch devices on their respective pivots 42, 45. The rack surface 31 will move across the detent 4| with a ratchet action and finally interlock and hold the rack arm towhatever position it may be extended with respect to the car. The catch devices will turn until their heels 41 abut the rests 45. Their points will dig far enough into the wall 48 to provide an adequate anchorage for the car. It has been pointed out that the catch devices 43 provide the main support. The brakes 33 also have a friction grip on the rails 29, thus balancing the holding function of the safety appliance, but the grip of the brakes 3B is not so great as to damage the rails.

I claim:-.

1. A safety appliance for an elevator car which has guides to run on rails, said appliance consisting of multiple brakes to engage the rails with a braking action, catch devices to dig into the walls of an elevatorwell, and linkage positively connecting the multiple brakes and catch devices so as to make them work in unison.

2. A safety appliance for an elevator car which has guides to run on rails, said appliance consisting of multiple brakes adjacent to the rails, catch devices in position to engage the walls of an elevator well, and linkage positively connecting said brakes and catch devices, said linkage turning the brakes into gripping positions against the rails and projecting the catch devices into digging positions into the walls of said well.

3. A safety appliance for an elevator car having guides to run on rails in an elevator well, said appliance consisting of multiple brakes adjacent to the rails, catch devices retracted from the wall of the well during the running condition of the car, and linkage positively connecting the brakes and catch devices to cause simultaneous operation upon breakage of a cable by which the car is carried, said brakes exercising an immediate braking effect on the rails because of their adjacency thereto, the catch devices engaging the well wall as soon as projected across the space from the car to the wall.

4. A safety appliance for an elevator car having guides to run on rails and an elevator well, said appliance consisting of multiple brakes at the top of the car, catch devices for the bottom of the car, linkage positively connecting the brakes and catch devices, a suspension head and means by which it is related directly with the multiple brakes to keep' the brakes and catch devices from working as long as a connected cable remains intact, and means including springs connected with the linkage simultaneously working the brakes and catch devices upon a cable breakage, the brakes gripping the rails at the top of the car and the catch devices digging into the well wall opposite to the bottom of the car.

5. A safety appliance for an elevator car to work in an elevator well, said appliance consisting of a detent in a rigid position with respect to the car, a catch device which is retracted from the well wall while the car is in running condition, and linkage which is worked to project the catch device into a digging-in position against the Well wall, said linkage including a crank, a rack arm carrying the catch device and being pivoted on the crank to turn when the catch device engages the wall, said arm having a rack surface to engage the detent and lock the catch 20- device in its extended position, and mutually coacting means on the arm and catch device then holding the catch device so that it will not turn.

6. A safety appliance for an elevator car to work in an elevator well, said appliance consisting of linkage which is operated upon the breakage of a cable suspending the car, a catch device carried by a part of said linkage and projected into a digging-in position against the well wall when the linkage is operated, and means by which 30 said linkage part is then interlocked with the car.

7. A safety appliance for an elevator car to work in an elevator well, said appliance consisting of a linkage and a spring by means of which the linkage is made to work upon the breakage of a suspending cable, said linkage including an arm which is projected toward the well wall by operation of the linkage, said arm having a rest, a catch device pivoted to the arm adjacent to 40 the rest and turning upon its pivot by the initial engagement with the wall until it abuts the rest when the point of the catch device digs into the wall, and fixed detent means with which the arm interlocks when projected so as to firmly hold 45 the catch device in its dug-in position.

8. A safety appliance for an elevator car to work in an. elevator well, a linkage and means by which it is operated upon the breakage of a suspending cable, said linkage including an arm which is projected from the car by said operation, a catch device carried by the arm and contacting the well wall, and means by which the arm is interlocked with the car by a turning of the arm resulting from said contacting of the catch device.

9. A safety appliance for an elevator car having guides to run on rails in an elevator well, a suspension head to which a cable is connected, said head consisting of a bar and a saddle which 60 has its extremities directed downwardly and virtually slotted to provide a bridge piece, a head bar forming part of the car through which the weight of the car is imposed on the saddle during suspension, a brake and a shaft to which it is attached, a stud on the shaft going vertically through the slot, said stud being held up by the bridge piece during suspension, means to shift the suspension head and saddle along the head bar toward said shaft upon a cable breakage thereby to displace the bridge piece from the stud, the slot then being advanced upon the stud so that the stud has room to move, and means to then turn the shaft so that the stud moves out- 75 wardlyin the slot and the brake moves into a gripping position against the rail.

10. Asafety appliance for an elevator car havingv guides to run on rails inv an elevator well, said car including a head. bar; a suspension head having a cable attached, to it. and being carried by the bar, multiple brakes and catch devices respectively to. engage the rail and the- Well wall, linkage connecting the. brakes and catch devices so as to make them workin unison, means. which keeps. the linkage from Working. as. longas. the cable remains. intact, a spring to move the. suspension head relatively to the head bar upon. a cable breakage so that the linkage. is not kept any longer from working, and a spring to then cause the linkage to work, said spring: being stronger than the spring of the suspension: head,

and further having means by which its tension can be adjusted.

11.. A safety appliance for an elevator car to work in an elevator well, a linkage and means by which it is operated by thebreakage: of a suswell, said applian'ce consisting of brake means on. the car near a rail, a catch device adapted to engagethe well. wall, and linkage carrying the catch device: and. connecting the catch device with the braleemeansysaid linkage applying the braking; means to the rail to adegree' in proportion to the distance necessarily traversed by the catch device for its. engagement with said wall. 29

ROBERT P. HOOKS.

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