US 3730463 A
A damping arrangement for preventing mechanical shocks from being transmitted to the supporting foot portions of apparatus mounted on a foundation located at any area of the earth's surface susceptible to earthquakes includes a two-part resilient mounting. The lower part of the mounting is rigidly fixed to the foundation and the upper part, to which the foot portion of the apparatus is attached, is connected with the lower part by means of a self-centering annular rubber body and a support plate which is guided for movement in any horizontal direction on the lower part by means of a low-friction type bearing placed therebetween in the form of a floating ring-shaped ball bearing retainer.
Claims available in
Description (OCR text may contain errors)
United States Patent 1191 Richard  SHOCK ABSORBING MOUNTINGS FOR APPARATUS  Inventor: Robert Richard, Zurich, Switzerland  Assignee: Aktiengesellschaft Brown, Boveri &
Cie, Baden, Switzerland 22 Filed: Apr. 20,1971
21 Appl. N0.: 135,664
 Foreign Application Priority Data May 6, 1970 Switzerland ..6791/70  References Cited UNITED STATES PATENTS 3,263,954 8/1966 Baratoff ..248/358 R 3,638,377 2/1972 Caspe ..152/167 3,146,979
9/1964 Keetch ..248/24X [4 1 May 1, 1973 2,014,643 9/1935 Bakker ..52/167 X FOREIGN PATENTS OR APPLICATIONS 826,879 l/1960 Great Britain ..248/358 R I Primary ExaminerJ. Franklin Foss Attorney-Pierce, Scheffler & Parker [5 7] ABSTRACT A damping arrangement for preventing mechanical shocks from being transmitted to the supporting foot portions of apparatus mounted on a foundation located at any area of the earths surface susceptible to earthquakes includes a two-part resilient mounting. The lower part of the mounting is rigidly fixed to the foundation and the upper part, to which the foot portion of the apparatus is attached, is connected with the lower part by means of a self-centering annular rubber body and a support plate which is guided for movement in any horizontal direction on the lower part by of v a low-friction type bearing placed therebetween in the form of a floating ring-shaped ball bearing retainer.
3 Claims, 4 Drawing Figures PATENTEB 11m 3,730,463
sum 1 BF 3 Fig. 1
PATENTEDHAY Hm 3,730,463
SHEET 2 BF 3 Fig.2b
PATENTEDHAY Hm 3,730,463
SHEET 3 OF 3 Fig. 3
SHOCK ABSORBING MOUNTINGS F OR APPARATUS The present invention relates to an improved damping arrangement for preventing mechanical shock movements of apparatus, which is adapted to be introduced between a foundation connected with the earth and a foot portion of the apparatus such as a machine or the like and particularly for switching apparatus that is to be mounted in locations which are susceptible to earthquakes. For the installation in earthquake susceptible areas of switching apparatus provided with pillar type insulators resiliently mounted on a foundation, it is known from Swiss Pat. No. 430,823 to provide, between the lower end of the pillar insulator and the base, an insert having two flanges between which are arranged spring elements in an asymmetrical manner. By means of such an arrangement the pillars cannot be dangerously deflected at their upper ends but are capable of oscillating to some extent about their center of gravity.
The primary object of this invention is to obviate these oscillations and prevent horizontal shock stresses from whatever direction such as occur, for example, with earth tremors from being transmitted to the apparatus. In accordance with the invention, this result is achieved in that in the lower part of the damping arrangement that is connected to the foundation, is guided the upper part connected to the foot of the apparatus, the guiding arrangement including a low-friction type bearing placed between the upper and lower parts in the form of a preferably floating ring-shaped ball bearing retainer which supports the weight of the upper part on the lower part and which permits horizontal movement of the upper part in any direction, and that a self-centering annular damping element is arranged between the lower and upper parts to restore the upper part to its initial position after the shock force terminates.
The foregoing, as well as other objects and advantages inherent in the invention will become more evident from the following detailed description of one suitable embodiment of the invention and from the accompanying drawings wherein:
FIG. 1 shows the damping arrangement in sectional elevation;
FIGS. 2a and 2b illustrate diagrammatically two different characteristic positions of the damping arrangement of FIG.1; and
FIG. 3 illustrates the damping arrangement installed in an electric switch of the compressed gas type.
With reference now to FIG. 1, the damping arrangement is designated in general by the reference numeral 1. It comprises a lower part designated generally by numeral 2. The lower part 2 is formed in two half sections 2a, 2b which are rigidly interconnected by means of screws 3. The lower part 2 is also provided with attachment holes, not illustrated, for connection with the foundation. Furthermore, the lower sections 2a, 2b are so constructed that they define a recess 4 in which is located an annular support plate 5 which is connected by means of a screw 7 to the central hub portion 6a of an inverted cup-shaped upper part 6 which is connected with the foot portion 9 of the apparatus which is not depicted in further detail in this view and is designated by a chain dot line. The connection between the foot portion 9 and the inverted cup-shaped upper part 6 is established by means of a bolt 8 which is threaded and a nut. A low friction bearing in the form of a ring-shaped ball bearing retainer 10 is provided at the upper and also. the lower side of the annular plate 5, one side of each race being in rolling contact with the corresponding side of the plate 5 and the other side being in contact with a stationary flat bearing ring 11. The bearing rings 11 are inserted into the sections 2a, 2b with the interposition of elastic rings 12 which are themselves located, in a resiliently stressed condition, in corresponding grooves in the sections 2a, 2b and provide for continuous contact of plate 5 with the balls of the ball retainers 10. It will be noted from FIG. 1 that the ball retainers 10 are seated in stepped portions 4a of the recesses 4, these stepped portions having a diameter somewhat larger than that of the ball retainers 10 so as to permit the latter to float, i.e. to have a limited degree of movement in any horizontal direction within the confines of the recessed portions 4a in which they are seated, along with movement of the upper part 6 in the event that shock forces occur. Maximum horizontal displacement of plate 5 is determined by the diameter of the recess 4 in relation to that of the plate 5.
The centering damping element 13, 13a is located between the cup-shaped upper part 6 and the lower section part 2b. Element 13 is constituted by an annular rubber body to the end surfaces of which are connected, e.g. by vulcanization, metallic limit rings 13a. The section 2a is provided with a central bore which is sealed by an insert 14. The ends of the clamping member 13, are secured to the lower section part 2b and the upper part 6.
With reference now to FIGS. 2a and 2b, corresponding parts have been given the same reference numerals as in FIG. 1. FIG.2a shows the normal relative self-centering position of the upper part 6 on the lower part 2 in the absence of any external forces. Should there occur however, for example, as indicated by the arrow 15, a horizontal movement of the earth,as a result of earth tremors, which is transmitted through the foundation to the part 2 connected therewith, then the position shown in FIG. 2b will result. It is assumed that a maximum deflection a has occurred between the central axes of the lower and upper parts 2 and 6. The rubber body 13 can deform and, as a result of the rolling friction between the parts 2 and 6 in any horizontal direction, accompanied by some horizontal displacement of the floating ball bearing retainer rings 10 in the same direction as depicted in FIG. 2b, practically no force is transmitted from the foundation to the apparatus, i.e. to the apparatus foot 9. Once the external force has ceased, the apparatus is returned automatically to the normal centralized rest position shown in FIG. 2a, by the restoring force built up in the self-centering resilient damping element 13 as the movement occurred. Any movement of the upper part 1 in a vertically upward direction on the lower part 2 is prevented by the presence of the upper bearing ball ring 10 which is in constant engagement between the upper side of support plate 5 and the upper bearing ring 1 1.
FIG. 3 illustrates an application of the damping arrangemen't l in the support of a compressed gas switch 16 which is provided with foot portion that are connected to the foundation 17, by means of the damping arrangement in accordance with FIG. 1.
The improved shock-absorbing support can also be employed to advantage for protecting machine apparatus from other types of stresses, for example, those resulting from high winds, towing forces and other shocks. By appropriately dimensioning the centering damping element 13, the latter can easily be adapted to the stress and the weight of the apparatus.
1. In a shock absorbing mount for absorbing horizontally directed shock forces in any direction and particularly those resulting from earthquakes, the combination comprising an upper part to which is adapted to be secured the apparatus to be protected against the shock forces, said upper part including a depending hub portion terminating in a circular support plate, and a lower part adapted to be secured to the ground, said lower part being constituted by upper and lower sections joined together and providing a circular recess into which said support plate extends, said recess including an upper bearing ring seated in said upper section and a lower bearing ring seated in said lower section, an upper ring of bearing balls disposed between said upper bearing ring and the upper side of said support plate, a lower ring of bearing balls disposed between said lower bearing ring and the under side of said support plate,
said upper and lower rings of bearing balls serving to prevent any displacement of said support plate in a vertical direction and also providing a low-friction bearing enabling horizontal movement of said lower part in any direction in response to earth shocks while said upper part remains virtually motionless, and an annular member of resilient material surrounding said hub portion of said upper part in radial spaced relation thereto, the upper and lower ends of said resilient annular member being respectively secured to said upper and lower parts thereby to provide a self-centerin g action of said upper part on said lower part after said shock forces terminate.
2. A shock absorbing mount as defined in claim 1 wherein each said bearing ring has associated therewith a resilient ring seated in a groove in said recess provided in said lower part, and each said resilient ring contacts the face of said bearing ring opposite to that which contacts the appertaining ring of bearing balls.
3. A shock absorbing mount as defined in claim 1 wherein each said ring of bearing balls is located in a portion of said circular recess having a larger diameter than the ball ring thereby enable relative transverse movement as between said ball ring and said lower part.