RU140990U1 - LABORATORY STAND FOR DETERMINING STRENGTH TAKING INTO ACCOUNT STILL Friction in Pointed Joints - Google Patents

Abstract

A laboratory bench for determining forces taking into account rest friction in pointed joints, consisting of an open ring rod, in which the upper end is connected with a fixed rotary hinge, the other end of the rod, starting with its three-quarter length, is directed vertically upward and also connected with a fixed rotary hinge, a rectangular beam is located inside the rod, touching the rod with pointed edges, the lower of which is located at the intersection of the vertical diameter with the rod, the upper point is scannia is located at the intersection of the diametrical line with the rod, forming a constant angle with the beam, which is half the angle formed by the vertical diametrical line and the perpendicular dropped from the center of the open ring rod to the beam direction, characterized in that the inner part of the open ring rod is equipped with a set pads with the possibility of hard fixing and removing them from the rod, and each of the pads has its own coefficient of rest friction.

Description

The utility model relates to laboratory equipment and can be applied in educational laboratories in theoretical and applied mechanics of technical universities, technical schools and technical schools.

There is a well-known stand for considering forces taking into account rest friction with external forces applied to it (Collection of tasks for term papers in theoretical mechanics: A manual for technical universities. - 7th ed., Revised. - M .: Integral-Press, 2001, p. 37, Fig. 34, Var. 25) the initial position of the supports and the lengths of the links of which are determined by the corresponding dimensions a , b, α, consisting of an open ring rod, whose upper end is connected with a fixed rotary hinge, the other end of the rod, starting from three quarters of its length, right it is vertically upward and also connected with a fixed rotary hinge; a rectangular beam is located inside the rod, touching the rod with pointed edges, the lower of which is located at the intersection of the vertical diameter with the rod, the upper contact point is located at the intersection of the diametrical line with the rod, forming a constant with the beam an angle that is two times smaller than the angle formed by the vertical diametrical line and the perpendicular dropped from the center of the open ring rod to the direction br sa.

The main disadvantage of the known stand is that it has a constant coefficient of rest friction in pointed joints, which does not allow students (students) to conduct educational research, both theoretical and experimental, to identify the dependence of the support reaction values on changes in the rest friction coefficient.

The problem the utility model aims to solve is that at the inner part of an open annular rod it is possible to change the static friction coefficients and provide students with scientific research, both theoretical and experimental, to identify the dependence of the support reaction values on the change in the static friction coefficient.

The technical result is achieved by the fact that in the laboratory bench for determining forces taking into account rest friction in pointed joints, consisting of an open ring rod, in which the upper end is connected with a fixed rotary hinge, the other end of the rod, starting with its three quarter length, is directed vertically up and also connected with a fixed rotary hinge, a rectangular beam is located inside the rod, touching the rod with pointed edges, the lower of which is located at the point of intersection of the vert diameter of the rod with the rod, the upper point of contact is located at the intersection of the diametric line with the rod, forming a constant angle with the beam, which is half the angle formed by the vertical diameter line and the perpendicular dropped from the center of the open ring rod to the beam direction, according to our proposal, the inner part of the open ring rod is equipped with a set of pads with the possibility of hard fixing and removing them from the rod, and each of the pads has its own coefficient of friction peace.

This design of the laboratory bench allows you to change the lining with the corresponding coefficients of rest friction on the inner part of the rod and to determine the reaction of the pointed supports, which provides for scientific research.

In FIG. The scheme of the stand is presented.

The laboratory bench for determining the forces, taking into account the rest friction in the pointed joints, consists of an open BDCAE ring rod, the upper end of which is connected to the fixed rotary hinge B. The other end of the rod, starting from its three quarter length, is directed vertically upward at point A and is also connected with a fixed rotary hinge E. Inside an open ring rod there is a squared beam CD, touching the rod with pointed edges. The lower contact point C is located at the intersection of the vertical diameter BC with the open ring rod. The highest point D of contact is located at the intersection of the diametrical line DOF with the rod, forming a constant angle a with the beam, which is half the angle 2α formed by the vertical diameter line BOC and perpendicular OK, omitted from the center O of the open ring rod to the direction of the beam CD. The inner part of the open annular rod is equipped with a set of pads 1 with the possibility of hard fastening and removing them from the rod, and each of the pads has its own coefficient of rest friction.

The laboratory stand works as follows.

With constant given parameters (adhesion coefficient), bond reactions can be determined only for these parameters. The methodology of theoretical calculations is given in the above literature (see an example of the assignment, p. 39-41). In this case, research is not possible.

In the proposed laboratory bench to the inner surface of the open annular rod, you can attach the pad 2 of constant thickness with the possibility of hard fastening and removal from the rod. There is a set of pads with different adhesion factors. Each pad has its own coefficient of friction of rest (clutch), for example, 0.10, 0.20, 0.30, 0.40, 0.45, etc.

The alternate installation of pads with different adhesion coefficients on the inner part of the rod helps to determine the corresponding bond reactions. This ensures the conduct of scientific research, both theoretical and experimental, to find the dependence of the magnitude of the reactions of bonds on the values of the coefficient of adhesion.

Thus, the proposed laboratory bench ensures the implementation of the tasks posed by the utility model.

Claims (1)

A laboratory bench for determining forces taking into account rest friction in pointed joints, consisting of an open ring rod, in which the upper end is connected with a fixed rotary hinge, the other end of the rod, starting with its three-quarter length, is directed vertically upward and also connected with a fixed rotary hinge, a rectangular beam is located inside the rod, touching the rod with pointed edges, the lower of which is located at the intersection of the vertical diameter with the rod, the upper point is scannia is located at the intersection of the diametrical line with the rod, forming a constant angle with the beam, which is half the angle formed by the vertical diametrical line and the perpendicular dropped from the center of the open ring rod to the beam direction, characterized in that the inner part of the open ring rod is equipped with a set pads with the possibility of hard fixing and removing them from the rod, and each of the pads has its own coefficient of rest friction.

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