Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16H—GEARING
  • F16H21/00—Gearings comprising primarily only links or levers, with or without slides
  • F16H21/04—Guiding mechanisms, e.g. for straight-line guidance

Definitions

• This invention relates to apparatus for providing accurate linear motion and in particular apparatus for providing accurate linear motion in machinery and other apparatus.
• apparatus for providing accurate linear motion In many machines and apparatus it is necessary to provide accurate linear movement of parts. This has proven to be most difficult and expensive.
• known linear bearings which must have low friction qualities and provide substantial accuracy add greatly to the cost of machines such as lathes and the like.
• the object of the present invention is to provide apparatus that is relatively inexpensive and of simple construction in providing for accurate linear motion.
• the invention provides a linear motion apparatus for providing linear motion comprising: a base member having a pair of spaced pivot points providing left and right pivot points respectively; a left rotating member pivotably connected to the left base pivot point, said left rotating member having a left member pivot point at the end thereof opposite to its connection to the base member; a right rotating member pivotably connected to the right pivot point of the base member, said right rotating member having a right member pivot point at the end thereof opposite to its connection to the base member; a joining member pivotably connected at its opposite ends to both the left rotating member at the left member pivot point and to the right rotating member at the right member pivot point whereby when the left rotating member rotates about the left base pivot point in a clockwise direction the right rotating member rotates about the right base pivot point in an anticlockwise direction and a point on the joining member midway between the left member pivot point and the right member pivot point describes a substantially straight line locus.
• the invention provides a linear motion machine having two linear motion apparatus arranged in mirror image including coupling means to couple the midway points of the joining members together whereby both apparatus rotate in sympathy and are prevented from moving independently of each other.
• FIGS 1a, 2a and 3a illustrate one form of linear motion apparatus according to an embodiment of the invention
• FIGS. 1b , 2b and 3b illustrate one form of transfer means according to an embodiment of the invention
• Figure 4 shows a linear motion machine having two linear motion apparatus and one embodiment of coupling means according to the invention.
• Figure 5 shows a similar linear motion machine to that shown in Figure 4 but having a coupling means according to another embodiment of the invention.
• the apparatus of the present invention includes a base means preferably in the form of a base member 11, such as a base bar.
• the base member 11 may form part of the machine in respect of which linear motion is desired and which will be explained more particularly below.
• the base member 11 includes a pair of spaced apart base pivot points.
• the spaced apart base pivot points will be referred to as a left base pivot point 15 and a right base pivot point 16 respectively. It will be appreciated, of course, that the geographical location of the pivot points is not material to the present invention.
• the apparatus of the present invention includes a left rotating member 12 pivotably connected to the left base pivot point 15.
• the left rotating member 12 may be of any suitable configuration and is preferably in the form of a bar.
• the left rotating member 12 has a left member pivot 17 at the end opposite to its connection to the base member 11.
• the apparatus includes a right rotating member 13 pivotally connected to the right pivot point 16 of the base member 11.
• the right rotating member 13 is in the form of a bar.
• the right rotating member 13 includes a right member pivot point 17 at its end opposite to its point of Preferably the distance between the left base pivot point 15 and the left member pivot point 18 is substantially equal to the distance between the right member pivot point 17 and the right base pivot point 16.
• the apparatus includes a joining member 14 pivotally connected at its opposite ends to both the left rotating member 12 at the left member pivot point 18 and to the right rotating member 13 at the right member pivot point 17 and so arranged that when the left rotating member 12 rotates on its left base pivot point 15 in a clockwise direction the right rotating member 13 will rotate on its right base pivot point 16 in an anticlockwise direction. That is to say when one member rotates anticlockwise the other will rotate clockwise and vice versa.
• the apparatus above described may be duplicated, one such apparatus being provided in a substantially mirror image of the other and positioned so that the lines of linear movement of the respective reference points are spaced apart and preferably in parallel.
• Embodiments of a linear motion machine having two apparatus in mirror image are shown in Figures 4 and 5. In this arrangement the respective reference points
• FIG. 19 and 19' in Figures 4 and 5 may each be provided as a reference pivot point.
• Coupling means are provided so that the respective apparatus are coupled together whereby both apparatus rotate in sympathy and are prevented from moving independently of the other. Any suitable, coupling means may be provided for this purpose.
• the coupling means may comprise a connection between the apparatus which ensures that they must move together and are not capable of any free independent movement.
• the coupling means may include a connection which may enable movement of one apparatus to move the other and includes drive means to ensure that independent movement does not occur.
• the drive means may include gearing, belting systems or any other suitable means.
• a pair of reference arms may be provided each pivotably mounted to a respective reference pivot point.
• first or left reference arm 36 and the other the second or right reference arm 37 For convenience the arm associated with a first one of the apparatus or the left apparatus of Figure 5 will be termed the first or left reference arm 36 and the other the second or right reference arm 37.
• a support member may be pivotably mounted to each reference arm.
• each support member 39, 40 is coupled to the midpoint of the respective reference arm as shown in Figure 5.
• the free end of each support member 39, 40 is held or mounted against movement. It has been found that as the reference points 19 and 19' move further from the midpoint above referred to any deviation from the accurate linear movement of one reference point will be compensated by a complementary deviation from the accurate linear movement of the other reference point.
• a pair of reference arms 34, 34' may be provided each pivotably mounted to a respective reference pivot point 19, 19' and joined together at a common linear point 35 so that they extend at an angle to each other.
• the angle between the reference arms is about 90o.
• the two sections of the apparatus will be identical but in mirror image the construction of parts may be varied desired and satisfactory results obtained.
• the lines of linear movement of the respective reference points be in substantial parallel. Satisfactory results can be obtained where those lines are disposed at an angle. In this event the line of movement of the linear point will accurately bisect the angle between the lines of movement of the respective reference points and compensate for any deviation from the accurate linear movement thereof in view of the complementary nature of the apparatus.
• the bars that make up the various components of the apparatus may be of any suitable shape and form.
• the bars may be made of any material such as aluminium or other metal.
• Any suitable pivot points may be provided but in the preferred arrangement these are provided by bearings or bushes of plastics or other material.
• transfer means may be provided.
• the transfer means of the present invention includes a reference member 22 pivotally connected to the reference point 19 on the joining member or where a duplicated apparatus is provided the reference member is connected to the linear point 35.
• the reference member is connected substantially at a point midway of its length to the reference point 19, 19' or linear point 35.
• the transfer means also includes a linear member 23 mounted in parallel with the reference member 22 by means of a pair of parallel link members 24, 25.
• One link member 24 ispivotally connected at one of its ends to an end of the reference member 22 and at its other end to the linear member 23.
• the other link member 25 is pivotally connected at one of its ends to the other end of the reference member 22 and at its other end to the linear member 23.
• the transfer means includes support means.
• the support means is in the form of a support member 21 or in the form of a part of the machine or the like in relation to which the apparatus is employed.
• the support means is 'fixed in relation to the base means.
• the support means may include a pair of spaced apart support pivot points 32, 33 hereinafter referred to as a left support pivot point 32 and a right support pivot point 33. Again the references to left and right should not be taken as restricting on the present invention.
• the transfer means may include a pair of parallel stay members, a left stay member 26 and a right stay member 27.
• the left stay member 26 is pivotally connected at one end to the left support pivot point 32 and at its other to one of the link members 25, preferably at a point midway along the length of the link member although this is by no means essential.
• the right stay member 27 is pivotally connected to the right support pivot point 33 and to the other link member 24.
• the apparatus of the present invention has a wide number of uses where the provision of an accurate linear motion is required.
• the apparatus has application in connection with lathes, with grinding machines, with radial arm saws, with milling machines, with planers, with metal 'working machines, in general, with cranes, with earth moving equipment, with hacksaws, and with various types of optical equipment.
• more than one apparatus according to the invention may be applied to any particular use. For example where additional rigidity is called for one or more sets of apparatus may be located along the length of the intended line of linear motion.
• a particular advantage of the present invention is that the apparatus provides great accuracy at low cost and in a simple manner.
• the known linear bearings can be dispensed with.
• a particular advantage is that there are no exposed surfaces where abrasion can occur and contaminants collect.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Transmission Devices (AREA)

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• 1981
  • 1981-11-19 EP EP19810903091 patent/EP0065530A1/de not_active Withdrawn
  • 1981-11-19 WO PCT/AU1981/000166 patent/WO1982001755A1/en not_active Ceased

Non-Patent Citations (1)

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