Fluid buffer for elevators

May 8, 1956

2,744,587

W. BECK

FLUID BUFFER FOR ELEVATORS

Sheets-Sheet 1

Filed Sept. 27, 1952

<img file="US2744587A_D0001.tif" />

<img file="US2744587A_D0002.tif" />

May 8, 1956 w. beck 2,744,587

FLUID BUFFER FOR ELEVATORS Filed Sept. 27, 1952 3 Sheets-Sheet 2

<img file="US2744587A_D0003.tif" />

5¼

<img file="US2744587A_D0004.tif" />

<img file="US2744587A_D0005.tif" />

May 8, 1956

2,744,587

W. BECK fluid buffer for elevators

Filed Sept. 27, 1952

Sheets-Sheet 3

<img file="US2744587A_D0006.tif" />

<img file="US2744587A_D0007.tif" />

United States Patent Office

2,744,587

Patented May 8, 1956

2,744,587

FLUID BUFFER FOR ELEVATORS ⁵

Walter Beck, Rock Island, DI., assignor to Montgomery Elevator Company, a corporation of Illinois

Application September 27,1952, Serial No. 311,901 ₁₍₎

Claims. (CI. 187—67)

This invention relates to improvements in fluid eleva- 15 tor buffers and particularly to improvements in construction which reduce the cost, facilitate the servicing and improve the operation of such buffers.

For many years, fluid buffers have been used as safety devices with elevators. Basically, such buffers comprise 20 a fluid filled cylinder with a piston movable therein. The buffer is placed at the bottom of the elevator pit in such a position that the piston rod will· be contacted by the descending elevator cage or counterweight. If all of the other safety devices, such as friction brakes and limit 25 switches, should fail and the elevator or the counterweight descend into the pit, its fall will be arrested and the shock of stopping will be cushioned by the oil damped piston. In the usual installation, two buffers are provided, one for the cage and the other for the counter- ³θ weight. Generally, these buffers also include a fluid reservoir surrounding the cylinder and a rather complex head casting which serves as an auxiliary reservoir and which provides means for guiding the piston rod. The complexity of this head casting makes it difficult and ³⁵costly to manufacture.

One object of my invention is to provide an improved: fluid elevator buffer. Another object is to provide such' a buffer in which the reservoir is provided with a substantially planar closure member of substantially the same ⁴⁰area as the reservoir, so as to avoid the need for a casting with a closed top and a partially closed bottom, with the resulting complexity of coring the casting. Yet another object is to provide a buffer in which the cylinder in which the piston travels is shorter than the surrounding ^4£* reservoir, and the member on top of the reservoir is provided with positioning means which engage the cylinder. Still·’another objects is to provide such a buffer with a filler tube attached to the reservoir and having the point of filling below the top of the cylinder.

Further objects and advantages will become apparent from the following specification and from the drawings in which: :

Fig. 1 is a side elevation of a lever type elevator buffer showing the elevator cage at ground level; ⁵⁵

Fig. 2 is a side elevation, similar to Fig. 1, but showing the elevator cage after it has descended into the pit, with the buffer in fully depressed position;

Fig. 3 is an enlarged sectional view taken as indicated along the line 3—3 in Fig. 4, with the spring guide member removed for added clarity;

Fig. 4 is an end elevation of the buffer, viewing Fig. 1 from the right, with some portions in section;

Fig. 5 is a fragmentary sectional view taken as indicated along the line 5—5 of Fig. 4; and

Fig. 6 is a diagrammatic sketch showing the relative movement of the lever and the yoke.

In the embodiment illustrated in the drawings, the invention is shown in connection with a lever type buffer as opposed to a straight-line, or standard type buffer. As will become evident, either type of buffer may be used. The straight-line buffer is generally installed in locations where the depth of the elevator pit is not critical. The lever type buffer was designed for use in situations where for some reason, such as where a building is built on bed rock, it is impractical or impossible to dig a pit deep enough to accommodate a standard buffer which may be almost 11 feet long in extended position and have a stroke of 4½ feet. A representative lever buffer may be less than 3 feet long, have a piston stroke of 7 inches and a lever arm movement of 2½ times the piston stroke.

Referring now to Fig. 1, the elevator cage 10 is shown with its floor 11 flush with the ground 12; and a lever type buffer, indicated generally at 13, is shown in a pit 14 beneath the elevator cage in its normal or raised position. Details of the elevator construction are omitted for the sake of simplicity.

The buffer 13 is provided with lever means 15 which is so positioned that if the other safety devices, such as friction brakes, motor speed governors, electro-magnetic brakes and limit switches, fail to operate and the cage 10 descends below the ground level 12, it strikes the lever means 15 so that its descent is arrested by the buffer and it comes to rest in the position shown in Fig. 2.

Referring now to Figs. 4 and 5, it will be seen that the lever type buffer 13 has a base consisting of a pair of upright channel members 16, and a transverse channel member 17. The base also includes a pair of upright extending legs 18 to which the lever means 15 are pivotally attached.

A reservoir 19 is secured to the transverse channel member 17 and extends upwardly therefrom. As shown here, this reservoir is cylindrical in shape; but it could take other forms, such as a rectangle. The top of the reservoir 19 is fitted with a closure member 20, which is sealed thereto by means of studs 21 welded to the reservoir and nuts 22. The closure member 20 has roughly the same cross sectional area as the reservoir, and is substantially planar. The closure member is provided with a downwardly extending positioning boss 23 which extends into the reservoir and is provided with a plurality of radial positioning fins 23«.

The manner in which the closure member 20 is fitted to the reservoir 19 should be noted particularly. In the past, these buffers have been constructed with the various parts threaded together, and as the diameters involved were rather large, the reservoir possibly being 8 inches in diameter, it was extremely difficult to maintain the desired standards of length or overall dimensions in the finished product. In the buffer shown, the abutting surfaces of the reservoir and the closure member are finished with a relatively high degree of accuracy, and the parts are then bolted together. This method of construction is now followed throughout, as will be seen.

A cylinder 24 is mounted on a block 25 inside the reservoir. The upper end 26 of the cylinder is spaced below the closure member 20, and engages the positioning fins 23«. The top of the cylinder is open to the reservoir through the cavities 36 between the fins. A plurality of apertures 27 are provided in the wall of the cylinder 24 communicating between the reservoir and the interior of the cylinder. The function of these apertures and the reason for the particular arrangement used will be explained later. A piston 28 is movable longitudinally in the cylinder, and the piston rings 29 provide a seal between the piston and the walls of the cylinder. A hollow, tubular piston rod 30 is affixed to the piston 28 and extends upwardly through a bore 31 in the closure member 20 and boss 23. The end surfaces of the piston rod and the abutting shoulder of the piston are finished with a high degree of accuracy and the parts are held together by means of pins 32. The upper end of the

2,744,587 of the elevator motors and control circuits as long as the' buffer is depressed.

After a defect has been remedied, the elevator mechanism may be raised from the pit and the buffer will resume its normal position, by virtue of the bias of the spring 41. The vent channel 51 will now be open, facilitating the recovery operation. The switch 61 will also return to its normal position, allowing the resumption of normal operation.

While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims.