SU480543A1 - Portable saw - Google Patents

Description

meters D, 1.45-1.55 times. The centers of the handles are located on the main central axis of inertia Xi of the frame symmetrically to its center of gravity.

The vertical main central axes of inertia of OiZi and Oz and Z2 of the frame and the engine are aligned with the axis of the cylinder of the engine.

The work of the suspension frame saws as follows.

The motor 1 generates spatial oscillations that are transmitted through the elastic elements 7, 8 and 9 to the frame with handles. The coincidence of the main central axes of inertia X, Y and Z and Xi, YI and Zj of the gas tank frame with the main central axes of rigidity of the spring system 7, 8, 9 and 13, 14 and 15 eliminates the coherence of spatial oscillations of the frame, gas tank and engine which narrows the spectrum of the natural frequencies of the system. The gas tank, elastically attached to the middle turns of the springs 7, 8 and 9, plays the role of a mechanical low-pass filter with transmission zero in the resonance region and, absorbing the energy of spatial frame oscillations, provides a greater degree of vibration isolation in the resonance frequency band coinciding with the saw operating modes when felling and cutting trees.

Since the lengths of the working parts of each spring are 1.45-1.55 times its average diameter, springs 7, 8 and 9 and 13, 14 and 15 acquire the property of equal stiffness, which makes it possible to further narrow the spectrum of the natural frequencies of the system.

Two-stage vibration isolation using a low-pass filter provides an increase in the total stiffness of the suspension spring without degrading the vibration-isolating effect.

Due to the arrangement of springs in the same plane at equal distances from the center of gravity of the frame and at equal angular intervals, as well as the symmetrical arrangement of the handles relative to the center of gravity of the frame, uniform load on each spring during operation is obtained, which leads to easier controllability and increase spring reliability.

The coincidence of the main central axes of inertia 02Z2 and OiZ of the frame and engine with the axis of the engine cylinder eliminates additional angular oscillations of the engine relative to the frame.

Subject invention

A portable motor-saw, including a motor with a saw, a rack, a gas tank and a frame with control handles, is connected with a rack of three spaced at equal angular intervals and equidistant from the center of the frame of the frame by helical coil springs, the axes of which intersect in the center of the plate of the frame the ends of the springs are rigidly fixed on the engine rack and on the frame, and a gas tank is rigidly attached to the middle turns of the springs, in order to increase the spatial vibration isolation of the handles on the working mode max, the gas tank is attached to the middle turns of the springs by means of two additional coil springs, the axes of which are located perpendicular to the axes of the springs connecting the frame and the engine, and the length of the working part of each of the additional springs is 1.45-1.55 times its length medium diameter.