US3380309A

US3380309A - Mechanical linkage

Info

Publication number: US3380309A
Application number: US535797A
Authority: US
Inventors: Douglas S Chisholm
Original assignee: Dow Chemical Co
Current assignee: Dow Chemical Co
Priority date: 1966-03-21
Filing date: 1966-03-21
Publication date: 1968-04-30
Anticipated expiration: 1985-04-30

Description

April 1953 D. s. CHISHOLM 3,380,309

MECHANICAL LINKAGE Filed March 21,. 1966 2 Sheets-Sheet l INVENTOR. 0009/06 6: C/I/S/w/m April 30, 1968 D. s. CHISHOLM 3,380,309

MECHANICAL LINKAGE Filed March 21, 1966 2 Sheets-Sheet :4

I N VE N TOR Daug/as 6. C/uLS/ra/m United States Patent 3,380,309 MECHANECAL LINKAGE Dougias S. Chishoim, Midland, Mich, assignor to The Dow Chemical Company, Midland, Mich, a corporation of Delaware Filed Mar. 21, 1966, Ser. No. 535,797 7 Claims. (Cl. 741) This invention relates to an improved mechanical linkage. It more particularly relates to an improved mechanical linkage capable of positioning a point on a predetermined curved line or surface.

Frequently in the construction of buildings having curved surfaces it is desirable to provide a guide or a tool which is readily positionable on or adjacent to the building structure in such a manner that the required design is adhered to. In cases of circular or spherical structures this is readily accomplished, for example, by pivoting an arm on the center of the desired structure. However, oftentimes it is desirable to generate structures wherein there is no ready access to the center. For example, in a spherical or spheroidal dome often a suitable geometric center is not available or in the case of a dome having an elliptical cross sectional configuration the centers of generation may be remote and inaccessible such as being positioned well within the earth. Oftentimes it is desired to support a construction unit such as a bricklaying machine or the like at the end of a boom or arm and position the terminal portion of the boom in such a manner that it serves as a guide and determines the final form of the structure. Such a technique is particularly advantageous when buildings are constructed from strips or portions of synthetic resinous foam which are adhered together to form the desired configuration.

It is an object of this invention to provide an improved mechanical linkage adapted to position an arm on a desired curved surface.

A further object of this invention is to provide a mechanical linkage for the multiplication or division of motion.

A further object of this invention is to provide an apparatus for the positioning of an operating mechanism in a guided pattern capable of generating a dome-like surface.

These benefits and other advantages in accordance with the present invention are achieved in an apparatus for the multiplication of linear motion comprising a frame, the frame having a first end and a second end, a first wheel disposed adjacent the first end, a second wheel disposed adjacent the second end, a movable support, first and second movable wheels aifixed to the movable support, the movable support being slideably positionable along the frame, a motion transmitting means extending from a point adjacent the first end of the frame about the first movable wheel, from the first movable wheel to the first wheel, about the first wheel, from the first wheel to the second wheel and about the second wheel, from the second wheel to the second movable wheel, about the second movable wheel and to a location generally adjacent to the second end of the frame.

Further features and advantages of the present inven tion will become more apparent from the following specification when taken in connection with the drawing wherein:

FIGURE 1 is a schematic representation of the operation of apparatus in accordance with the invention;

FIGURE 2 is a schematic representation of an alternate embodiment of the invention;

FIGURES 3 and 4 depict a compact arrangement of apparatus employing a principle of the apparatus of FIG- URE 2; and

FIGURE 5 is a schematic representation of an operat- 3,38%,309 Patented Apr. 30, 1968 ing apparatus such as is depicted in FIGURES 3 and 4 particularly adapted for tracing curved surfaces.

In FIGURE 1 there is schematically depicted an apparatus which is generally designated by the reference numeral 10. The apparatus 10 comprises a frame or support 11 having a first end 12 and a second end 13. A first wheel 15 is pivotally affixed to the first end 12 of the frame 11. A second wheel 16 is pivotally afifixed to the second end 13 of the frame 11. A movable wheel support 17 is slideably disposed on the frame 11 and adapted to move between the first and

second ends

12 and 13, respectively. The support 17 carries a first movable wheel 18 and a second movable wheel 19. By the term wheel is meant a pulley gear, sprocket gear drum or the like. A motion transmitting means 21 such as a sprocket chain, cable or belt is affixed to the first end 12 of the frame 11 at location 22. Motion transmitting means 21 extends from location 22, about the wheel 18, from the wheel 18 to the wheel 15, about the wheel 15 and toward the second end 13, about the wheel 16 and toward the wheel 19, about the wheel 19 to location 24 generally adjacent the second end 13 of the frame 11. A point P is disposed upon the movable wheel support 17. A second point P is disposed on the motion transmitting means 21 which extends between the

wheels

15 or 16. Motion of the support 17 causes the point P to be moved a given distance whereupon the point P will be moved twice the distance the support 17 is moved. Thus, by moving the point P the point P is caused to move a distance twice that which the point P was moved. Similarly, if motion is applied to the point P and it is moved a given distance, the point P will be moved one-half of that distance. Thus, the apparatus 10 provides motion multiplication or division by a factor of 2.

In FIGURE 2 there is illustrated an alternate embodiment of the invention generally designated by reference numeral 25. The apparatus 25 comprises a frame 26 having first end 27 and second end 28. First, second and

third wheels

29, 30 and 31 are disposed adjacent the first end 27 and pivotally mounted thereon and adapted to retate about generally parallel axes. Third, fourth and

fifth wheels

33, 34 and 35, respectively, are pivotally mounted on the second end 28 of the frame 26 and are adapted to pivotally rotate about generally parallel axes. A movable support 36 is disposed slideably adjacent the frame 26 and then disposed intermediate the first and

second ends

27 and 28. The support 36 carries a plurality of wheels, the 7th, 8th, 9th and

10th wheels

37, 38, 39 and 40, respectively. A motion transmitting means 41 such as a belt, cable or sprocket chain extends between the first and fourth wheels, about the fourth wheel to the ninth wheel, about the ninth wheel to the fifth wheel, about the fifth wheel to the tenth wheel, about the tenth wheel to the sixth wheel, about the sixth wheel to the third wheel, about the third wheel to the eighth wheel, about the eighth wheel to the second wheel, about the second wheel to the seventh wheel, about the seventh wheel to the first wheel and to the fourth wheel. Advantageously, a tensioning means 43 such as a spring is disposed within the motion transmitting means of 41 and adapted to maintain tension thereon. A portion of the motion transmitting means 41 is secured to the frame at a location 44. A point P is disposed 0n the wheel carrier 47 and the point P is disposed on the motion transmitting means 41 which extends between the first and fourth wheels. Movement of the point P toward the second end of the frame for a distance d causes the point P to move a distance 4d toward the first end 27 of the frame 26, thus providing a constant factor of 4. Thus, in essence the apparatus 25 provides a pantographic arm with a constant ratio of 4.

In FIGURES 3 and 4 there is schematically depicted a practical arrangement of the motion transmitting configuration of the FIGURE 2 and is generally designated by the reference numeral 5%. The apparatus 59 comprises a frame 5 having a first end 52, a second end 53. A shaft is disposed adjacent to the first end 52 and supports first, second and

third pulley wheels

57, 58 and 59, respectively. A shaft 60 is disposed adjacent to the second end 53 and supports fourth, fifth and

sixth wheels

61, 62 and 63, respectively. A movable wheel support 65 is disposed between the first and

second ends

52 and 53 for frame 51. The pulley support 65 supports a first shaft 67 which carries seventh and eighth wheels 69 and 70, respectively. A second shaft 71 carries the ninth and tenth wheels 72 and 73, respectively. A motion transmitting means such as a belt, cable or sprocket chain 75 passes about the wheels in the manner as demonstrated in PEG- URE 2 and operating means 76 is afiixed to the motion transmitting means 75 extending between the first and fourth wheels and an actuating means 77 is aiiixed to the support 65. A pivot 78 is affixed to the first end 52 and frame 51.

In FIGURE 5 there is a schematic representation of an apparatus 89 having a motion multiplication means 50 as illustrated in FIGURES 3 and 4 pivotally ailixed by its first end 52 and pivot 78 to a rotatable support 81. The support 81 is pivotally aiiixed to a base 82 by means of a pivot 83 having an axis of rotation which is in a plane normal to the axis of rotation of the pivot 78. Beneficially, a support or guide wheel 84 is affixed to the support 81 and adapted to engage the base 82. A template 85 is affixed to the base 81 generally adjacent to the pivot 78. The base 85 has an edge 86 which defines a desired curve and is adapted to engage the actuating means 77 of the apparatus 50 and cause the operating means 76 to be positioned along the frame 51 in proportion to the displacement of the actuating means 77 caused by the edge or model surface 86. Thus, the apparatus by rotation of the apparatus 50 about the pivot 78 and rotation of the base about the pivot 83 permits the operating means 76 to be positioned on a curved surf-ace of generation four times the size of the surface of generation of the edge 86.

Beneficially either of the embodiments of the apparatus in accordance with the present invention are advantageously employed for such applications as the construction of buildings having generally circular cross sections, for the rotation of radiating devices such as those emitting high energy ionizing radiation about a center remote from the apparatus. Also beneficially, such radiation devices as radar antennas are rotated without the necessity of providing large circular tracks or bearings.

As is apparent from the foregoing specification, the apparatus of the present invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. For this reason, it is to be fully understood that all of the foregoing is intended to be merely illustrative and is not to be construed or interpreted as being restrictive or otherwise limiting of the present invention, excepting as it is set forth and defined in the hereto appended claims.

What is claimed is:

1. An apparatus for the multiplication of linear motion comprising a frame, the frame having a first end, a second end, a first wheel disposed adjacent the first end, a second wheel disposed adjacent the second end, a movable support, first and second movable wheels affixed to the movable support, the movable support being slideably positionable along the frame, a motion transmitting means extending from a point adjacent the first end of the frame about the first movable wheel, from the first movable wheel to the first wheel, about the first wheel, from the first wheel to the second wheel, about the second wheel, from the second wheel to the second movable wheel and to a location generally adjacent the second end of the frame.

2. The apparatus of claim 1 wherein the motion transmitting means is resiliently secured to the frame.

3. The apparatus of claim 1 wherein a plurality of wheels are fixed rotatably to the first end and a like number of wheels are atfixed to the second end; a number of movable wheels mounted on a slideable support and disposed intermediate the wheels on the first and second ends wherein the linear motion transmitting means primarily interconnects slideable wheels adjacent the first end and slideable wheels adjacent the second end with the wheels of the first end and the second end, respectively, by passing about at least a portion of the periphery thereof and the linear motion transmitting means extending between not more than two wheels of the first end and of the second end.

4. The apparatus of claim 3 including a support; a pivot pivotally securing the first end of the frame to the support; and means to slideably position the movable support in a predetermined pattern.

5. The apparatus of claim 4 wherein the support is pivotally supported to rotate about an axis generally normal to the axis of the pivot securing the first end of the frame to the support.

6. The apparatus of claim 5 wherein the movable support has affixed thereto a follower, a template positioned adjacent the frame, the template having an edge which engages the follower and thereby positions the movable support in a predetermined manner.

7. The apparatus of claim 1 wherein a separating means is affixed to the linear motion transmitting means at a location wherein the linear motion transmitting means extends between a wheel of the first end and a wheel of the second end.

No references cited.

FRED C. MATTERN, In, Primary Examiner.

C. J. HUSAR, Assistant Examiner.