GB2044879A

GB2044879A - Drive mechanism for converting rotary to reciprocating motion and vice versa

Info

Publication number: GB2044879A
Application number: GB7911085A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1979-03-29
Filing date: 1979-03-29
Publication date: 1980-10-22
Also published as: GB2044879B

Abstract

A drive transfer mechanism, for the conversion of rotary motion to reciprocal motion and vice versa, comprises a rotatable plate 1 and a reciprocatable piston 5 connected together by a connecting rod 3 at points of connection 6, 7 both eccentric to the axis of rotation of the plate 1. The plate 1 or the piston 5 can be the driven member, the other being driven through the connecting rod 3. As shown, a tatooing needle incorporates the drive mechanism. <IMAGE>

Description

SPECIFICATION Drive transfer means and application thereof This invention relates to a drive transfer mechanism and to an application thereof.

Mechanisms for the transfer of rotational drive to reciprocating motion and vice versa are known but in many instances the mechanisms are complex in construction and are not adapted to miniturisation and the mounting of the drive in a substantially 'in line' construction.

It is an object of the present invention to provide a drive transfer mechanism adapted to convert rotary drive to reciprocating motion and vice versa which mechanism is simple in construction, capable of miniturisation and can be mounted in a substantially 'in line' construction.

Accordingly, the present invention provides a drive transfer mechanism comprising a driven or drivable reciprocating member connected to a driven or drivable rotary member, wherein the reciprocal member is a piston or plunger and the rotary member is a rotatable plate, the reciprocating and the rotary member being connected together by a connecting rod provided with universal joints at each connecting end and having points of connection to the plate and to the piston or plunger each eccentric with regard to the axis of rotation of the plate and drive means for the rotary or for the reciprocating member.

The eccentric connection of the connecting rod to the plate and piston (or plunger) can be achieved in various ways. Thus, for example, the connecting rod can extend from an eccentric mounting on the plate to a transverse extension on the piston provided with a universal joint for connection of the rod to the extension and in this manner the piston itself can be mounted axially of the drive to the rotatory plate giving a truly 'in line' arrangement.

In another embodiment of the drive mechanism of the invention the connecting rod can extend from an eccentric mounting on the plate directly to the piston which can itself be mounted eccentrically with respect to the axis of the drive means for the rotatory member.

This arrangement produces an 'off line' construction which can be of use where the construction of the device embodying the drive mechanism does not require a completely 'in line' disposition.

The principal of the invention can also be applied to drive means in which the rotatory plate is inclined at an angle to the axis of the piston or plunger and the connecting rod is attached eccentrically to the plate with respect to the axis of rotation of the plate.

The drive mechanism of the invention operates in all its embodiments by the relative displacement of the points of connection of the connecting rod produced by the rotation of the plate and the 'shortening' of the rod as it moves into a position in which the connecting points reach the point of maximum displacement from one another. This 'shortening' of the rod produces in the piston a reciprocating motion directly in proportion to the rotation of the plate. Where the piston is the driven member, the reciprocation of the piston produces a corresponding rotation of the plate.

It is preferred that the piston or plunger be so mounted that it is not capable of rotation; indeed, this is an essential feature of the embodiment of the invention in which the connecting rod extends between an eccentric mounting on the plate and a mounting on an extension on the piston.

Ball and socket joints are suitable for the universal joints at the ends of the connecting rods.

The drive means for the rotary plate or for the piston or plunger can be any conventional means, for miniturised equipment incorporating the drive means of the invention, electrical drive through gearing is preferred.

The drive means of the invention is suitable for use with any device where it is desired to transfer rotary drive to reciprocating motion, or vice versa.

One specialised device in which the drive means of the invention has proved to be of particular value is an automatic tattoo needle.

In addition to the so-called cosmetic use of tattooing, the principle is also used to a great extent in medical laboratories where animals used in the testing of drugs are coded by tattooing to ensure that a correct record of the course of any experiment can be assured.

Specifically, mice and rats used in such experiments are usually tattooed in the tail region so that they may be readily identified throughout the experiment.

Presently existing tattooing devices are cumbersome and non-aesthetic resulting from the use of drive means which makes it impossible to design an apparatus which is efficient in use and in appearance. Such conventional drive means include solenoid drive and drive by way of pulleys. In both cases the final instrument is clumsy and/or heavy.

Using the drive mechanism of the present invention it is possible to design a tattooing device which is effective, of convenient size and weight and has an appearance more in keeping with the scientific instruments used in the laboratory.

The basic principal of any tattooing device is the reciprocation of a needle acting in an ink reservoir so that the intermittent puncturing of the skin by the needle loaded with ink results in the build up of a design related to the movement of the needle over the skin.

The drive mechanism of the invention is ideally suited for incorporation into such a device since the drive can be mounted substantially 'in line' and can be made on the small scale necessary for the incorporation into a hand held device.

Accordingly, the present invention also provides a tattooing device which comprises, serially arranged, drive means, a shaft rotata ble by the drive means, a plate fixedly mounted on the shaft, a connecting rod fixed by universal joints to the plate and to a reciprocal piston or plunger, the connecting rod being fixed to the piston or plunger and to the plate at positions eccentric with respect to the axis of rotation of the plate, a second connecting means connected axially of the piston or plunger and a tattooing needle attached axially to the second connecting means, which needle acts in an ink reservoir, or is provided with inking means. The whole device is, of course, mounted in a suitable housing.

It is preferred to use a small electric motor as the drive means in the tattoo device of the invention, the motor may drive the plate direct or through gearing.

The invention is further illustrated by the accompanying drawings in which Figure 1 represents diagrammatically one embodiment of the drive mechanism of the invention; Figure 2 represents another embodiment of the drive mechanism of the invention, and Figure 3 represents the incorporation of a drive mechanism according to the invention into a tattooing device.

Referring now to Figs. 1 and 2 of the drawings, a rotatable plate (1) is driven by a motor (not shown) by way of shaft (2). Plate (1) is connected by connecting rod (3) to an extension (4) fixedly mounted on piston (5).

The connecting rod (3) is mounted on to plate (1) and extension (4) by universal joints (6) and (7) respectively. Rotation of the plate (1) with the piston (5) held against rotation but capable of reciprocal motion causes relative displacement of the universal joint (6) with respect to joint (7) with the resulting 'shortening' of the connecting rod (3) and reciprocation of the piston (5).

In Fig. 2, the plate is angled with respect to the axis of the piston (5) and, again, rotation of the plate results in the relative displacement of the joints (6) and (7) reciprocation of the piston. In this embodiment the piston need not be held against rotation.

Referring now to Fig. 3, the motor is connected by shaft (2) to rotatable plate (1) which is connected by connecting rod (3) provided with universal joints (6) and (7) to extension (4) of piston (5). Piston (5) is connected by a second connecting rod to tattooing needle (9) which acts in an ink reservoir (10).

Action of the drive means (motor) results in the rotation of the shaft, reciprocation of the piston (5) and of the needle (9) which in use punctures the skin and carries into the skin ink from the reservoir (10).

Claims

1. A drive transfer mechanism comprising a driven or drivable reciprocating member connected to a driven or drivable rotary member, wherein the reciprocal member is a piston or plunger and the rotary member is a rotatable plate, the reciprocating and the rotary member being connected together by a connecting rod provided with universal joints at each connecting end and having points of connection to the plate and to the piston or plunger each eccentric with regard to the axis of rotation of the plate and drive means for the rotary or for the reciprocating member.

2. A drive mechanism as claimed in claim 1, wherein the connecting rod extends from an eccentric mounting on the plate to a transverse extension on the piston or plunger which is mounted axially of the shaft.

3. A drive mechanism as claimed in claim 1, wherein the connecting rod extends directly between the piston or plunger and an eccentric mounting on the plate and the plate is mounted for rotation at an angle to the axis of the piston or plunger.

4. A drive means as claimed in claim 1, wherein the connecting rod extends between an eccentric mounting on the plate and to the piston or plunger which is positioned 'off line' with respect to the axis of the shaft but parallel thereto.

5. A drive mechanism as claimed in claim 1, substantially as described with reference to Figs. 1 and 2 of the accompanying drawings.

6. A tattooing device which comprises drive means connected to a drive transfer mechanism as claimed in any of the preceding claims, a connecting means from the piston or plunger of the drive transfer means and, connected thereto, a tattooing needle acting within an ink reservoir or provided with inking means.

7. A tattooing device as claimed in claim 6, substantially as described with reference to Fig. 3 of the accompanying drawings.