Dual/slipper shock mount

A shock absorber mount is described as having two pressed fittings which are mounted in end-to-end relationship. Each insert has two rigid, radially spaced cylindrical sleeves which are separated by a resilient rubber insert. The inner sleeve of the vertically lowermost fitting, when the fittings are properly mounted on, for example, an automobile frame, extends upwardly beyond the associated outer sleeve and is coated with rubber to enter a hollow bore formed by the inner sleeve of the upper fitting. The extension allows the lower fitting to initially absorb an upwardly applied axial force until it moves into shock absorbing relation with the upper fitting. The extension also acts to bolster the radial shock absorbing characteristics of the upper fitting to provide improved shock absorbing characteristics of the mount; namely, low axial shock absorption and high radial shock absorption.

BACKGROUND OF INVENTION 
The invention relates to a shock dampening mount which employs resilient 
elastomeric cushions, especially a mount which is positioned between a 
conventional shock absorber and an automobile frame. Two important 
parameters for designing such a mount are, 1) a low axial rate of shock 
absorption to control noise and vibration entering the passenger 
compartment, and 11) a high radial rate of shock absorption to provide 
better vehicle handling. The invention successfully incorporates both of 
these parameters. 
Briefly stated, the invention is in a shock absorbing mount which comprises 
two pressed metal/elastomeric parts which are mounted together in 
end-to-end relation. Each part has a pair of concentric cylindrical metal 
sleeves which are radially spaced about a vertical axis when the parts are 
vertically disposed in stacked relation. A resilient elastomeric insert is 
secured between each pair of metal sleeves. The inner sleeve of the 
vertically lowermost part extends beyond the outer sleeve thereof for 
slidable receipt in the bore formed by the hollow inner sleeve of the 
vertically uppermost part. The extension of the inner sleeve of the lower 
part is covered with rubber which can be coated with a substance to 
decrease the friction between the rubber on the extended lower inner 
sleeve and the inner sleeve of the upper part. The parts are designed so 
that the lower part will move axially upward a short distance before 
engaging the top part to provide the lowest possible axial rate of shock 
absorption. Further, the lower sleeve extension buttresses or reinforces 
the upper part to increase the rate of shock absorption in a radial 
direction. 
These two parts like those of copending application Ser. No. 07,590,762, 
filed Oct. 1, 1990 are simplistic in design, so that they are easily 
assembled and inexpensive to manufacture.

DETAILED DESCRIPTION OF DRAWING 
With reference to the drawing, there is shown a shock absorbing mount 5 for 
securing a conventional shock absorber 6 to an automobile frame 7. The 
mount 5, when assembled in vertical relation as represented in FIG. 1, 
comprises a metal mounting plate 8 which is secured to the adjacent 
automobile frame 7, the plate 8 having a vertically disposed, hollow 
cylindrical housing 9 for receiving a pair of upper and lower pressed 
metal/elastomeric parts or fittings 10, 11 which surround the upper shaft 
12 of the shock absorber 6, and which are held there in the housing 9 by a 
pair of vertically spaced metal washers 13, 14 and lock nut 15. 
The upper pressed fitting 10 comprises a pair of concentrically disposed 
rigid cylindrical sleeves 16, 17, which are radially spaced by an annular 
insert 18 which is composed of any suitable resilient elastomeric 
material, e.g. rubber. The upper end 19 of the outer sleeve 17 is curved 
or flared outwardly to rest on the adjacent, upper curved end 20 of the 
housing 9 to limit travel of the upper pressed fitting 10 in the direction 
of the lower pressed fitting 11. The upper, radially outermost end 21 of 
the rubber insert 18 is matingly curved to rest atop the outwardly curved 
end or flange 19 of the outer sleeve 17. An annular rubber collar 22, 
integral with the rubber insert 18, is formed atop the insert 18 and 
flange 21, and is provided with a corrugated outer end 23 for engaging the 
upper metal washer 13, depending on the transitional design parameters 
desired between the upper washer 13 and abutting upper pressed fitting 10. 
The vertically lowermost end 24 of the rubber insert 18 is provided with 
an inwardly directed void or cavity 25, which is formed by opposing 
sidewall sections 26, 27 which are tapered and converge in the direction 
of the upper washer 13. The inner sleeve 16 of the upper pressed fitting 
10 is shorter than the outer sleeve 17 and is composed of either metal or 
plastic and, in this instance, is formed of plastic to enhance slippage 
between the upper and lower pressed fittings 10, 11, as will become 
apparent from the description of the lower pressed fitting 11. 
The lower pressed fitting 11 also has a pair of rigid, radially spaced, 
concentric inner and outer cylindrical metal sleeves 30, 31 between which 
is a rubber insert 32. The lower inner sleeve 30 is substantially longer 
than the lower outer sleeve 31 to form an inner sleeve extension 33 which 
extends beyond the upper rim 34 of the lower outer sleeve 31. The inner 
sleeve extension 33 is covered by a thin layer 35 of rubber which is 
integral with the rubber insert 32. The rubber coated sleeve extension 33 
is designed to be slidably received in the bore 36 formed inside the 
hollow inner plastic sleeve 16 of the upper pressed fitting 10. To further 
enhance slippage between these two parts, the outer cylindrical rubber 
surface 37 of the sleeve extension 33 can be coated with any suitable 
material which further reduces the coefficient of friction between the 
upper plastic sleeve 16 and the lower sleeve extension 33. The lower end 
38 of the lower outer sleeve 31 is flared radially outwardly to form an 
annular flange which engages the adjacent lower end 39 of the housing 9 to 
limit travel of the lower pressed fitting 11 in the direction of the upper 
pressed fitting 10. The lower end 40 of the lower rubber insert 32 is 
matingly curved to rest against the lower curved flange 38 of the lower 
outer sleeve 31. A corrugated rubber collar 41 is also provided at the 
lower end 42 of the lower rubber insert 32 to engage the adjacent lower 
metal washer 14 which, in this instance, is a conventional jounce bumper 
43 which includes a cylindrical rubber shock absorber 44 and surrounding 
dust tube 45, and which is not a part of the invention. The lower rubber 
insert 32 is provided with an annular void or cavity 46 which extends 
inwardly of the insert 32 from the upper end 47 of the insert 32 closest 
the upper pressed fitting 10. The thickness of the sidewalls 48, 49 
forming the cavity 46, may vary, as best seen in FIG. 2. 
The shock absorbing mount 5 is designed such that the lower pressed fitting 
11 will move a predetermined axial distance, e.g. 3 millimeters, before it 
encounters or engages the upper pressed fitting 10. Thus, it can be 
appreciated by those skilled in the art that the initial shock vertically 
imposed axially upwardly against the shock absorber mount 5, will be 
absorbed entirely by the slideable lower pressed fitting 11 to minimize 
shock absorption in an axial direction in accordance with the 
aforementioned first important design parameter. The lower, outer sleeve 
extension 33 within the bore 36 of the upper pressed fitting 10, acts to 
bolster or reinforce the radial shock absorbing capabilities of the upper 
pressed fitting 10 as it coacts with the lower pressed fitting 11, to 
maximize the radial shock absorbing characteristics of the mount 5 in 
accordance with the second design parament outlined above. 
Thus, there has been described a mount which has a unique sleeve extension 
which allows axial slippage between the pressed, shock absorbing fittings 
of the mount, as well as increases the radial shock absorbing 
characteristics of the fittings. It is believed that this unusual design 
and interaction of the fittings optimises the two import design 
characteristics desired in a mount of this type; namely, a low shock 
absorption in an axial direction and a high shock absorption in a radial 
direction. 
The shock absorbing rate of the mount can be adjusted or tuned by varying 
the composition of the rubber insert, or by varying the size, location, or 
geometric shape of the cavities in the rubber insert, or by varying the 
size or geometric shape of the sleeves to which the rubber units are 
secured.