1. Field of the Invention
The invention relates to a mount for reducing vibrations transmitted from a tool to a carrier vehicle, such as a tractor. More specifically, the mount isolates a tractor from the vibrations of a vibratory plow, or similar tool.
2. Description of the Prior Art
In the past, different approaches have been tried to minimize the transfer of vibrations from a tool to a carrier vehicle, such as a tractor. The vibrations generally tire out the tractor operator and cause the bolted parts of the tractor to come apart, necessitating re-tightening of these bolts. The wear on the tractor parts also increases. The vibrating tool, for example a plow, is generally mounted on a sub-frame having a vibrating means attached to the sub-frame. The sub-frame is held by vibration dampening means in a larger frame. Examples of this construction are shown in U.S. Pat. No. 5,526,590 (Palm et al.), U.S. Pat. No. 5,482,121 (Draney et al.), U.S. Pat. No. 3,746,100 (Hall et al.), U.S. Pat. No. 4,140,425 (Flippin) and U.S. Pat. No. 4,164,982 (Draney). These solutions all share the apparent disadvantage of excessive wear and tear on the vibration dampening means, due to the fact that the sub-frame is vibrating in all directions. This subjects the vibration dampening means to compression (tensile) and shear stress. Most vibration means are rubber pads (or similar material), and inherently much less suited to shear stress, as compared to tensile stress. The vibration dampening means therefor wear out excessively fast in these applications. Also, the efficiency of vibration damping is not high enough to properly dampen vibrations from reaching the tractor.
A further attempt to provide a vibratory plow construction with vibration dampening means is disclosed in U.S. Pat. No. 4,867,607 (Johnson et al.). This document discloses a pivotable part of the vibratory plow carrying frame. The frame elements are separated by air cushions (or resilient dampening means of other types), arranged to dampen vertical movement of the frame parts. This construction necessitates the use of extra frame parts, to achieve the pivoting of the frame, thus adding weight, complexity and cost to the construction. If solid rubber vibration dampers are used, they are objected to shear stress, which is detrimental to the life of such dampers.