RU220636U1 - Working body of the cleaver - Google Patents

Abstract

The utility model relates to devices for splitting wood and can be used in industrial equipment and hand tools. The working body of the cleaver is wedge-shaped in the area of the cutting edge located at the intersection of the cheeks. Part of the cheek surfaces is made of a protruding cylindrical shape, the beginning of which is 20...50 mm away from the cutting edge. The axes of the cylindrical surfaces of the cheeks are parallel to the cutting edge and located on the opposite side relative to the plane of symmetry of the working body. The design of the device is created taking into account the characteristics of splitting timber. The use of the device increases the service life of the tool and reduces the cost of its production.

Description

The utility model relates to devices for splitting wood and can be used in industrial equipment and hand tools in the production of process chips, firewood for boiler houses, etc.

The prerequisites for creating a useful model are the features of the wood splitting process, which includes two successive stages - cutting and splitting (Borisov A.Yu. Improving the technology of processing aspen wood into roofing material, taking into account natural and production conditions: dissertation ... candidate of technical sciences: 05.21 .01.-Petr.SU, Petrozavodsk, 2017, Fig. 3.13). At the cutting stage, the movement of the working body of the cleaver occurs in proportion to the acting force, in accordance with Hooke's law. When the critical penetration depth is reached, an advanced crack is formed and the splitting stage begins, while an increase in the length of the crack is accompanied by a decrease in the applied force. Thus, an effective working body of the splitting ax should provide easy cutting in the first stage and productive splitting in the second.

As a result of the analysis of the current level of technology, similar devices were found that are similar in technical essence and the achieved result. They are kinematic mechanisms, the operating mode of which changes during operation.

The working body of a splitting ax is known (RF Patent No. 208918, B27L 7/06, B26B 23/00, publ. 01/21/2022), containing a group of splitting-expanding elements with wedge-shaped ends of symmetrical shape forming a single line of the cutting edge. At the splitting stage, the cutting edge line has the shape of a broken line and the splitting-expanding elements push the edges of the crack apart.

The disadvantage of the device is that the cutting-in stage of the device in question is not designed to achieve an advanced crack, since the existing inertial masses (loads weighing 0.05 kg or more) almost immediately transfer the device to the splitting mode, before the formation of an advanced crack. As a result, at the plunge stage, a violation of the geometry of the cutting edge will occur, leading to a decrease in the efficiency of the tool. Moreover, due to the plasticity of wood in the direction across the grain, groups of elements that make up the cutting edge can perform cutting in different planes and thereby prevent splitting.

A known splitting wedge with expanding levers (US Patent No. 3865163, A47J 49/02, B27L 7/00, publ. 02/11/1975), containing a wedge-shaped blade of symmetrical shape and two hingedly connected U-shaped levers with a swing axis lying in the splitting plane and parallel to the cutting edge. During the first stage of work, the blade cuts into the timber and an advanced crack is formed. At the second stage, the levers rest against the upper edges of the crack and split the timber, turning around an axis.

The disadvantage of the tool is its complex design containing massive levers. At the splitting stage, most of the effective force applied to the tool is lost when projected onto a plane perpendicular to the splitting plane. The return of the levers to their original position occurs due to gravity and this does not ensure sufficient reliability of the device. Chips formed during the destruction of timber can get between the moving parts of the mechanism and disrupt its operation.

The prototype of the utility model is a prefabricated cleaver (US Patent No. 4044808, A47J 4/02, B26B 23/00, B27L 7/00, publ. 08/30/1977), containing a head part with a cutting edge and two levers connected by a hinge. When cutting the head part to a depth sufficient to form an advanced crack, the levers rest against the outer edges of the crack and push them apart until the timber is completely destroyed. After the splitting stage is completed, the arms are returned to their original position using springs or magnets.

The disadvantage of the prototype is its complex design containing several moving parts. In addition, part of the acting force is spent on overcoming the return force of the spring or magnet. The holes in the head into which the levers return may become clogged with wood chips and prevent the tool from working properly. The operation of the cleaver is complicated by the need for periodic lubrication of the lever axes.

It should be noted that all the considered analogues and the prototype have a common positive property due to the fact that parts of the levers abutting the upper edges of the crack move along the trajectories of cylindrical surfaces of a protruding shape. The latter allows you to effectively move the edges of the crack apart.

The purpose of the utility model is to create a high-performance and reliable tool for splitting wood, taking into account the features of the process of splitting wood before and after the formation of an advanced crack.

The technical result of the utility model is to create an easy-to-use design of the working body of the cleaver that does not contain moving parts, ensuring effective splitting.

The result is achieved by the fact that the working body of the cleaver has a symmetrical shape, wedge-shaped in the area of the cutting edge located at the intersection of the cheeks; part of the cheek surfaces is made of a protruding cylindrical shape. In this case, the beginning of the cylindrical shape of the surfaces is removed from the cutting edge by 20...50 mm. The axes of the cylindrical surfaces of the cheeks are parallel to the cutting edge and located on the opposite side relative to the plane of symmetry of the working body.

The essence of the utility model is illustrated by drawings and a photo of a prototype, which shows:

figure 1 - cross-section of the working body of the cleaver perpendicular to the plane of symmetry (splitting);

figure 2 - view A of the working body of the cleaver in figure 1;

Fig. 3 is a photo of a general view of a splitting ax created on the basis of a utility model;

Fig.4 - photo of the splitting ax Fig.3 from the side opposite the handle.

The working body of the cleaver is made symmetrically relative to the splitting plane AA. In the area of the cutting edge 1, the working body has a wedge-shaped shape. Part of the surfaces of the cheeks 2, 3 is made of a protruding cylindrical shape 4, 5. The axes of the cylindrical surfaces of the cheeks 6, 7 are located on the opposite side relative to the plane of symmetry of the working body. The beginning of the cylindrical shape of the cheek surfaces is removed from the cutting edge at a distance “a” of 20...50 mm. The specified value ensures guaranteed formation of an advanced crack at the cutting-in stage of the working element and effective splitting at the final stage of splitting.

The production of the proposed tool is possible by cutting, forging or casting.

Tests of a prototype splitting ax with a head mass of 2.5 kg (Fig. 3, Fig. 4) confirmed the successful solution of the task.

At the cutting stage, the wedge-shaped part of the working body of the cleaver easily penetrates the timber to a depth of 20...50 mm (depending on the type of timber, humidity, etc.) until an advanced crack forms. Then splitting occurs with the movement of the edges of the crack along the generatrices of the cylindrical surfaces of the cheeks 4, 5. The design of the device takes into account the requirements for the tool that change during the splitting cycle. Easy penetration before the formation of an advanced crack and effective splitting at the final stage.

The use of a utility model increases the service life of the tool and reduces the cost of its manufacture.

Claims (1)

The working body of the cleaver is symmetrically shaped, wedge-shaped in the area of the cutting edge located at the intersection of the cheeks, characterized in that part of the cheek surfaces is made of a protruding cylindrical shape, the beginning of which is 20...50 mm away from the cutting edge, and the axes of the cylindrical surfaces of the cheeks are parallel to the cutting edge and located on opposite sides relative to the plane of symmetry of the working body.