The subject of the invention is a motion conversion device that realises the

mechanical conversion between rotary and reciprocating motions with the option to switch this conversion on/off, that is, in a reversibly switchable manner.

Conversion between rotary and reciprocating motions is used in many situations, in a wide variety of applications; accordingly, a large number of solutions exist for it.

Some of these are presented in the 1974 "Motion conversion devices" slide series, part of a series of educational films created by the Ministry of Labour http://dia.osaarchivum.orq/public/index.php?fs=3146 ; as well as in

Peter Horvath: A mechatronika alapjai (Fundamentals of mechatronics) (Szechenyi University, Gyor, 2006) Chapter 8.2., Classification of motion transmission mechanisms (pages 146 - 151 ), where motion transmission mechanisms between rotary-rotary and linear-linear motions are referred to as transmitters, while those between rotary and linear motions as converters.

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Table 8.1 Classification of motion transmission mechanisms

Transmitter rotary- rotary cogwheel pair, chain drive, belt drive, friction drive, Maltese cross

linear-linear lever transmission

Converter rotary-linear spindle-nut, rack and pinion, sinusoidal mechanism According to this classification the solution proposed in the invention is of a design suitable for both the transmitter and converter functions, selecting between those at will.

During work processes the subsequent use of tools which perform rotary / linear motion is often necessary. Most often this requires the alternating use of several machines, or fitting onto /disassembling from the same machine a motion converting adapter. Another known solution is the use of multifunctional tools (such as the drill bit, which also "saws" in the direction perpendicular to its rotation axis), which however, typically require compromises in terms of each of their functions to be suitable for this.

In order to reduce inconveniences, time requirements, and costs, and at the same time guarantee the quality of work, a device capable of generating different forms of motion without replacement or fitting is needed.

Our goal was to create such a device, based on the idea that by altering the constraints that define the operation of the motion converter we can alter its functioning in a reversible manner.

The essence of the solution given by the invention is described in the main claim of the patent application, while some of its advantageous design elements in the additional claims.

The invention is presented in more detail in the following drawings.

The drawings depict:

Figure 1 shows the sketch of a possible design of the device proposed by the invention;

Figure 2 shows the device shown in Figure 1 , rotated by 90 degrees;

Figure 3 shows the sketch of the device from Figure 1 in switched mode;

Figure 4 shows the device shown in Figure 3, rotated by 90 degrees;

Figure 5 shows the sketch of another possible design of the device proposed by the invention

Figure 6 shows the sketch of the device from Figure 5 in switched mode;

Figure 7 shows the lengthwise section of a manual tool containing the device shown in Figure 6; Figure 8 shows an enlarged detail of Figure 7;

Figure 9 is the spatial depiction of the detail from Figure 8, with exploded details.

The device proposed by the invention consists of a rotor (1 ), the part that performs reciprocating motion (2), the motion conversion device connected to them, the mechanism that connects and separates the elements that provide the mechanical constraint - and thereby switches between rotary and reciprocating motions - and in the case of the design example of the manual tool, from the universal chucks.

During the transformation between forms of motion it is often the case that reciprocating motion has to be converted into continuous rotary motion, or vice versa. To realise this, a constraint has to be established between the actuator and the element being moved, which exists continuously during their motion, and can be referred to as an internal constraint.

If the actuator is subject to a constraint which only permits rotation or linear motion, with an opposing constraint acting on the element being moved, which only permits linear motion or rotation - which we can call external constraints - then the possible movement of the actuator is transformed into the possible movement of the element being moved.

In most motion conversion mechanisms the direction of linear motion with respect to the rotary motion is radial. Examples for this include the traditional crank mechanism, as well as eccentric solutions, most of which have a radial design.

In figures 1 - 4 we have outlined an arrangement in which the rotor (1 ) and the part performing reciprocating motion (2) are arranged with parallel axes, ideally with a common axis along axle 10. In Figures 1 - 2 the wheel (14) rotates around a fixed axle (1 1 ), and the rod attached to it (15) moves the part performing reciprocating motion (2). Rotary motions are shown by the arrows 13, reciprocating motions by the arrows 12. If, however, we secure the wheel (14) against rotation, while permitting the rotation of the support frame (16) around axle (10), all parts shown in Figures 3 - 4 will rotate, and reciprocating motion will cease. A more balanced structure than this example can be created using a constraint path mechanism.

In motion conversion mechanisms based on a constraint path the internal constraint is provided by a power transmission element guided along a constraint path. It is evident that if the axes of the rotary and linear motions are identical, then the contact point between the constraint path and the power transmission element will move along the surface of a cylinder. (Obadovics: Matematika (Mathematics) (Muszaki konyvkiado, 1974., pages 347-348)

The definition of constraint path can be found in professional literature, see e.g. "Muszaki lexikon" (Technical encyclopedia) (Akademiai Kiado, 1972) Volume 2, page 496.

In Figures 5 - 6 parts with a shape of a solid of revolution are arranged along parallel axes (ideally a common axis), with a constraint path mechanism (23) between the outer part (20) and the inner part (21 ) and a power transmission element (25) fitted into a groove (24), which forces the inner part (21 ) - which is secured against rotation with an element that blocks due to its form (7) - to perform the reciprocating motion shown by arrow 12 when the outer part (20) rotates according to arrow 13. If, however, blocking against absolute rotation is altered to blocking against relative rotation with respect to the outer part (20), that is, the inner part (21 ) is secured to the outer part (20), then with the blocking element shown in Figure 6 all components will rotate and the reciprocating motion towards the outer part will cease.

In Figures 7 - 9 we present how this can be realised, taking the example of a hand tool constructed with the described constraint path mechanism.

The battery (28) built into the housing (29) operates the motor (27), which rotates the outer part (20) around the axle (6). In the example shown, the inner part (21 ) is secured to the outer part (20) by the element that blocks due to its form (7), which is led through the slot of the groove (26) and connected to the pawls (8). If, however, the blocking element (7) is moved to position 9 using the switching ring (22), then by connecting to the pawls (8) secured to the housing (19) it will secure the unit against relative rotation with respect to the housing (19), and the inner part (21 ) will perform reciprocating motion. As a result, the desired function can be achieved and switched by a part located on an accessible point of the machine's housing and switchable with a single movement, which is connected to 4 function switching units, allowing practical switching to the desired form of motion from the outside.

As can be seen, the drive can perform either rotary or reciprocating motion, and its power supply may be provided from any type of source.

The area of application of the invention can be piston- or eccentric systems or systems that require the conversion of motion, which wish to develop this conversion further and use it to drive a drilling-, grinding-, de-burring, polishing- or any other rotary tool. This presents a possible further area of application: works performed using any known tool designed for reciprocating motion, such as reciprocating saws, rasps, or tools used for polishing or evening out uneven surfaces using reciprocating motion.

For holding the tools, the tried and tested solutions can be used, but when using tools with a unique end profile, securing only the tool appropriate for the operation, securing against inadvertent switching or switching between operating modes for the fitted tool are also possible.

With an appropriate design our invention can also be used regardless of the direct external environment, for example in vacuum or underwater, where lightweight and versatile tools are needed.

If the constraint path is realised along the shaft of the motor, even less material is required, with a simpler design and lower production cost, while maintaining quality. In this case, certain parts no longer need to be produced and reciprocating motion can be achieved by connecting a single element that blocks rotation to the machine.