US797931A - Safety device for elevators. - Google Patents

Description

No. 797,931. PATENTED AUG. 22, 1905- F. H. BABGOOK'.

SAFETY DEVICE FORBLEVATORS. APPLICATION FILED FEB. 9. 1005.

ELEVATO FL.

Inventor.

Attorney mmiw. 5 annual 00., FDDTO-LIMOGRAFMRS. wwumton. l1 (2.

UNITED STATES PATENT OFFICE.

SAFETY DEVICE FOR ELEVATORS.

Specification of Letters Patent.

Patented Aug. 22, 1905.

Application filed February 9, 1905. Serial No. 244,934.

To all whom, it may concern:

Be it known that I, FRANK H. BABCOGK, a citizen of the United States, residing at Butler, in the county of Butler and State of Pennsylvania, have invented a new and useful Safety Device for Elevators, of which the following is a specification.

This invention relates to automatic regulators for controlling the descent of elevators and other hoists, and has for its principal object to provide means for automatically retarding the downward movement of the loadcarrier with a view of preventing accidents in case of damage to the hoisting mechanism.

A further object of the invention is to provide a regulating means in which the load or weight automatically adjusts the mechanism to an extent proportioned to the load or weight.

With these and other objects in view, as will more fully hereinafter appear, the'invention consists in certain novel features of construction and arrangement of parts hereinafter fully described, illustrated. in the accompanying drawings, and particularly pointed out in the appended claims, it being understood that various changes in the form, proportions, size, and minor details of the structure may be made without departing from the spirit or sacrificing any of the advantages of the invention.

In the accompanying drawings, Figure 1 is an elevation, partly in section, of a safety device constructed in accordance with the invention. Fig. 2 is a transverse sectional view of the same on the line 2 2 of Fig. 1. Fig. 3 is a sectional plan view of one of the dash-pots on the line 3 3 of Fig. 1. Fig. 4 is a detail sectional view illustrating a modification of the invention.

Similar numerals of reference are employed to indicate corresponding parts throughout the several figures of the drawm s.

The device forming the subject of the present invention is intended to be applied to elevators, hoists, and the like for the purpose of controlling the speed of descent of the elevator in case of accident or in case of breakage of the ordinary hoisting-cables, although in some cases the apparatus itself may be employed as the hoisting mechan- 1sm.

At the top of the elevator-shaft is arranged a suitable supporting-platform 10, on which is mounted a frame 11 that is provided with sockets 12, generally two in number. In these sockets are placed blocks 15, formed of rubber or some similar yieldable material, each provided with a passage 16, which at its lower end communicates with a valved nipple 17, that is carried by the platform or frame.

Seated on the rubber blocks or cushions are the lower ends of vertical cylinders 18, that are provided with openings 19 in communication with the openings 16, and in each of these cylinders is a trunk-piston 20, working up and down in the cylinder, and the latter forming a dash-pot for controlling the speed of movement of said piston.

Secured to each of the cylinders is a frame 21, that is guided in part by the main frame 11. The frame 21 is provided with bearings for the reception of a horizontal shaft 23, that is provided at its opposite ends with cranks 24, that are connected by rods 25 to the pistons, said cranks being preferably arranged diametrically opposite to each other, so that while one piston is moving in one direction the second piston will be moving in the opposite direction.

On the shaft is a loosely-mounted drum 26, that is divided by an annular flange 27 into two winding-surfaces, one of which, 28, serves to receive'a flat belt or similar sus pending device 29, while the other windingspace 30 has a helical groove for the reception of a cable 31, the latter extending over a suitable guiding-sheave 32 and carrying at its opposite end a suitable weight 33. The lower end of the strip 29 is connected to the elevator-cage or other load-carrier, and as the latter descends the weighted cable 31 will be wound upon the drum, and as the elevator moves upward the strap 29 will be wound, while the weight 33 will descend.

Secured to the shaft are one or more ratchet-wheels 34, and one or both ends of the drum serve as supports for pivoted pawls of transversely -extending ribs 37, throu h which and through the opposite sides of t e piston extends a pin 38, arranged to receive the inner end of the pitman-rod, and the latter fits between the two ribs 37 and is held from displacement.

During the upward movement of the elevator the weight 33 will descend and through the medium of the cable 31 will turn the drum 26 in one direction and will wind the strap 29 thereon, and during this movement the pawls 35 will click over the ratchetwheels 34 without turning the shaft. On downwardmovement the pistons will be re ciprocated in the cylinders, and the elevator may descend at a rate of speed determined by the previous adjustment of the nipples 17. Should the hoisting-cables break or the elevator accidentally fall from any other cause,

the whole weight of the elevator and its load will be imposed on the springs and the yieldable blocks 15, whereupon said blocks will be compressed, and the diameter of each of the passages 16 will be contracted to an extent proportioned to the load, so that the heavier the load the greater the resistance to the passage of the air to and from the cylinder, and if the load is exceedingly heavy the assage will be entirely closed and the e evator brought to a stop. This is found highly advantageous in that it is much more dangerous for a heavy-loaded carriage or elevator to descend rapidly than a light load, and as the resistance in all cases is sufficient to prevent downward movement of the elevator at such speed as to injure either the elevator or its contents no injury can result from the descent of either a light or heavy load; but where a large quantity or weight or many passengers are in the car the speed is retarded in proportion to the load and any acceleration of the speed from acquired momentum is prevented.

It is obvious that various other pressurecontrolled means may be employed for regulating the area of the passage, as, for instance, in Fig. 4 I have shown the socket members in the form of cylinders 12, that contain glycerin or other liquid which is forced under pressure through a pipe 40, lead ing to a valve mechanism 41, and as the pressure on the liquid increases the valve will be gradually closed, so that the resistance to the passage of air to and from the dash-pots will a be increased in proportion to the load.

It is obvious that the resistance of the rubber blocks may be increased by embedding suitable helical or other springs therein or by surrounding the block proper by helical springs.

Having thus described the invention, what is claimed is 1. In a safety appliance for elevators and the like, means for retarding the descent of the load, and means automatically adjustable by the weight of the load for controlling the resistance of such retarding means.

2. In a safety appliance for elevators and the like, a dash-pot for controlling the speed of descent of the load, and means adjustable automatically by the weight of the load for governing the resistance offered by said dashpot.

3. In a speed-controlling device for elevators and the like, a dash-pot having a by-pass or opening, and means controlled by the weight of the load for governing the area of such bypass or opening.

4. In a safety appliance for elevators and the like, a dash-pot having an opening through which fluid is pumped during the descent of the load, and means controlled by the weight of the load for automatically adjusting the area of the opening.

5. In a safety appliance for elevators and the like, a dash-pot, and a compressible member having a fluid-passage in communication with the dashpot, said compressible member being subjected to the weight of the load, and serving as it yields and expands to alter the effective area of the opening.

6. In a speed appliance for elevators or the like, a frame having a socket, a block of compressible material arranged therein and provided with a fluid-passage, a dash-pot having an opening in communication with the passage and resting on the block, a shaft, a winding-drum mounted on the shaft, a flexible connecting member extending between the elevator and the winding-drum, a crank carried by the shaft, and a piston connected to the crank.

7. In a safety appliance for elevators and the like, a frame having a pair of sockets, blocks of compressible material disposed in said sockets and provided with fluid-pas sages, dash-pots resting on said blocks and provided with openings in communication with the passages, valved nipples also communicating with said passages, an auxiliary frame guided by the main frame and secured to said dash-pots, a shaft mounted on the auxiliary frame, a ratchet-wheel rigid with the shaft, cranks secured to said shaft, pistons connected to the cranks, awinding-drum loose on the shaft, a pawl carried by the windingdrum and engaging the ratchetwheel, a flexible winding member extending between the elevator and the winding-drum, and a second flexible winding member also connected to the drum and provided with a counterweight.

In testimony that I claim the foregoing as my own I have hereto affixed my signature in the presence of two witnesses.

FRANK II. BABCOOK.

Witnesses:

J. H. JooHUM, Jr., FRANK S. APPLEMAN.

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