US3589013A

US3589013A - Beam compass

Info

Publication number: US3589013A
Application number: US868994A
Authority: US
Inventors: Miquel Angel Rivera Colon
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-10-24
Filing date: 1969-10-24
Publication date: 1971-06-29
Anticipated expiration: 1988-06-29

Abstract

A trammel head assembly, characterized by the provision of improved locking means for rigidly locking the trammel body to a scale upon which it is slidably mounted. More particularly, the means for locking the trammel body to the triangular scale comprises a yoke member having a transverse portion extending longitudinally completely through said opening, and a pair of parallel leg portions that extend integrally from the ends of said transverse portion within corresponding grooves contained in the ends of said trammel body. Screw means connected with said body are arranged to engage the ends of said leg portions to laterally displace said yoke means in a locking direction relative to the scale.

Description

United States Patent [72] Inventor Miquel Angel Rivera Colon 625 Artico SL, Puerto Nuevo, PR. 00920 [211 App]. No. 868,994 [22] Filed Oct. 24, 1969 [45] Patented June 29, 197] [54] BEAM COMPASS 7 Claims, 4 Drawing Figs.

[52] US. Cl 33/27 [5| Int. CL t B43l 9/04 [50] Field oISearch 33/27 (C), 158. 159, 160. I73 [56] References Cited UNITED STATES PATENTS 365,031 6/l887 Trout 33/158 648,576 5/1900 Taylor 33/158 Primary Examiner- Leonard Forman Assistant Examiner-Charles E. Phillips Attorney-Scrivener, Parker, Scrivener and Clarke engage the ends of said leg portions to laterally displace said yoke means in a locking direction relative to the scale.

PATENTED JUH29l97l 3,589,013

6, lmml 26 INVENTOR MIGUEL ANGEL RIVERA COLON BEAM COMPASS As evidenced by the US patents to Hansdorfer No. 447,642 and Nelson No. 1,219,141, it is known in the patented prior art to provide dividers or scribing means of the trammel type including a trammel head that is mounted for sliding movement upon a scale or ruler. Furthermore, as shown by the Zurcher US. Pat. No. 2,974,416, it is known to provide trammel apparatus of the type referred to above that is adapted for use with a triangular scale. The present invention was developed to provide an improved trammel head especially designed for use in connection with a triangular scale of the type having a longitudinal groove in each of the three scale faces.

The primary object of the present invention is to provide an improved trammel head having an opening for slidably receiving a triangular scale, and locking means for locking the head to the scale. The invention is characterized in that the locking means includes a yoke having a transverse portion that ex tends longitudinally through the opening, and parallel leg portions that are slidably guided in vertical grooves contained in the ends of the body, respectively. Screw means are provided for displacing said yoke in the locking direction to force the transverse portion into the corresponding groove in the scale, the yoke being accurately guided by the grooves in which the yoke leg portions are received.

A more specific object of the invention is to provide a trammel head of the type described above, wherein the yoke means has a U-shaped configuration, the ends of the yoke leg portions including inwardly directed stop projections that limit the extent of downward movement of the yoke in the locking direction. The screw means for displacing the yoke in the locking direction include a screw member secured at one end with the trammel body between the ends of and parallel with the yoke leg portions, and a nut member threadably connected with the screw means and adapted to engage the ends of the yoke leg portions for displacing the yoke in the locking direction.

Other objects and advantages of the invention will become apparent from a study of the following specification when viewed in the light of the accompanying drawing, in which:

FIGS. 1 and 2 are exploded and end elevation views, respectively, of the trammel body;

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2; and

FIG. 4 is a perspective view illustrating a pair of trammel heads mounted on a triangular scale or rule.

Referring now to the drawing, the trammel head 2 includes a triangular body 4 having a triangular opening 6 for slidably receiving a triangular scale 8 in any ofits three l20-displaced positions of orientation. Secured at one end to and extending downwardly from the apex portion of the trammel body is a selected scribe means (such as a pin 10 or a pencil 12, as shown in FIG. 4). Referring to FIG. 3, the pin 10 has a threaded upper shank portion that is secured in a correspond ing bore in the lower apex portion of the trammel body. When not in use, the pin may be enclosed by a protective removable cover 14.

in accordance with the present invention, improved means are provided for locking the trammel body at a selected position on the scale. To this end, yoke means 18 are provided having a transverse portion 18a that extends longitudinally through the body opening 6, and a pair of

parallel leg portions

18b, 18c integral with the ends of said transverse portion. The leg portions are slidably received in corresponding

vertical grooves

4b, 4c, respectively, contained in the ends of trammel body 4 intermediate the upper apices thereof, whereby the yoke 18 is accurately guided in the vertical plane containing the scribe means 10 as shown in FIG. 2. At their upper ends. the leg portions 18b and 18: are provided with inwardly directed top projections 180' that limit the downward extent of movement ofthe yoke means in the locking direction.

On each of the three faces of the triangular scale 8 is provided a longitudinal groove 20 as is conventional in the art. in

order to displace the yoke means downwardly to force the transverse portion 18a into frictional locking engagement with the adjacent groove 20, screw means are provided that include a vertical screw member 22 secured at its lower end to the central upper portion of body 4 between the

yoke leg portions

18b and 18c, said screw member extending upwardly and having threadably connected thereto a knurled nut 26 the lower surface of which is adapted to engage the upper surfaces of the free extremities of the leg portions 118k and 180. Thus when the scale is assembled within the body opening 6 and the nut 26 is tightened to displace the yoke 18 downwardly, the rounded lower extremity of the transverse portion 18a is forced within the longitudinal groove 20 to frictionally lock the trammel to the scale.

In order to permit accurate positioning of the trammel head on the scale, preferably the body 4 is formed of a transparent material (such as a suitable synthetic plastic material) and is provided on each of the wall surfaces ofthe triangular opening 6 with indicia lines 30 that are visible when the trammel head is assembled on the scale. While the yoke and nut members may be formed of any suitable rigid metallic or nonmetallic material, preferably these components are also formed of a suitable transparent synthetic plastic: material. The scale 8, which is a conventional drafting scale commonly used by architects, draftsmen and engineers, normally has a length of 6, l2, 18 or 24 inches and is generally formed of metal, wood or a synthetic plastic material.

To use the trammel apparatus as a beam compass, the trammel body carrying the pin 10 is adjusted to a position opposite the zero indicia on the selected scale, whereupon the righthand trammel body is positioned at a given spaced distance as indicated by the desired scale indicia visible therethrough. Following tightening of the nuts to functionally lock the trammel bodies to the scale, the pencil l2 and scale 8 can be swung in an are about the pin 10.

While in accordance with the provisions of the Patent Statutes the preferred form and embodiment of the invention has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made in the apparatus described without deviating from the inventive concept.

What I claim is:

l. A trammel head adapted for concentric slidable mounting upon a scale, comprising a trammel body containing an opening for receiving a scale;

and means for releasably locking said trammel body to said scale, comprising a yoke member having a transverse portion extending longitudinally completely through said opening, and a pair of parallel leg portions each of which is integral at one end with opposite ends ofsaid transverse portion, respectively, said leg portions being slidably received in parallel-opposed grooves contained in said trammel body, respectively, and screw means cooperating with the other ends of said leg portions for effecting coplanar displacement of said yoke member in a locking direction to effect frictional locking engagement between said transverse portion and said scale. 2. A trammel head as defined in claim 1, wherein said yoke member is generally U-shaped and includes adjacent the extremities of said leg portions on the adjacent surfaces thereof inwardly directed projection means adapted to cooperate with the external surfaces of said body member to limit the extent of movement of said yoke member in the locking direction.

3. A trammel head as defined in claim 2, wherein the opening contained in the trammel body is generally triangular, and further wherein the lateral surface of the transverse portion of said yoke member remote from said trammel body is rounded for locking cooperation within a corresponding longitudinal groove contained between two apices of a triangular scale.

4. A trammel head as defined in claim 2, wherein said screw means comprises a screw member coplanar with both said trammel body and said yoke member, said screw member being connected at one end with said trammel body and extending outwardly from the external surface thereof parallel with and arranged between said leg portions, and a nut member threadably connected with said screw member and arranged for engagement with the extremities of said leg portions to displace said yoke member in the locking direction.

5. A trammel head as defined in claim 4, wherein said trammel body is generally triangular and includes external surfaces generally parallel with the corresponding wall surfaces of said triangular opening.

6. A trammel head assembly as defined in claim 5, wherein said trammel body includes scribe means contained in the plane of and extending outwardly from one apex portion of said body, and further wherein said yoke means, said screw member and said scribe means are contained in a vertical central plane that extends midway between the other two apices of said trammel body.

7. Trammel apparatus including, in combination,

a triangular scale including in each of the three faces thereof a groove extending longitudinally substantially the full length thereof;

a trammel head mounted for sliding movement on said scale, said head including a triangular body containing a triangular opening corresponding with the cross-sectional configuration of and slidably receiving said scale; and

means for locking said trammel head to said scale, comprising a yoke having a transverse portion extending longitudinally through said opening, and a pair ofleg portions integral with the ends ofsaid transverse portion and slidably received in corresponding parallel grooves contained in the ends of said body, respectively, and screw means con nected with said body for cooperation with said leg portions to displace said yoke in a direction to force said transverse yoke portion into function-locked engagement with the corresponding groove is said scale.

Claims

1. A trammel head adapted for concentric slidable mounting upon a scale, comprising a trammel body containing an opening for receiving a scale; and means for releasably locking said trammel body to said scale, comprising a yoke member having a transverse poRtion extending longitudinally completely through said opening, and a pair of parallel leg portions each of which is integral at one end with opposite ends of said transverse portion, respectively, said leg portions being slidably received in parallel-opposed grooves contained in said trammel body, respectively, and screw means cooperating with the other ends of said leg portions for effecting coplanar displacement of said yoke member in a locking direction to effect frictional locking engagement between said transverse portion and said scale.

2. A trammel head as defined in claim 1, wherein said yoke member is generally U-shaped and includes adjacent the extremities of said leg portions on the adjacent surfaces thereof inwardly directed projection means adapted to cooperate with the external surfaces of said body member to limit the extent of movement of said yoke member in the locking direction.

7. Trammel apparatus including, in combination, a triangular scale including in each of the three faces thereof a groove extending longitudinally substantially the full length thereof; a trammel head mounted for sliding movement on said scale, said head including a triangular body containing a triangular opening corresponding with the cross-sectional configuration of and slidably receiving said scale; and means for locking said trammel head to said scale, comprising a yoke having a transverse portion extending longitudinally through said opening, and a pair of leg portions integral with the ends of said transverse portion and slidably received in corresponding parallel grooves contained in the ends of said body, respectively, and screw means connected with said body for cooperation with said leg portions to displace said yoke in a direction to force said transverse yoke portion into function-locked engagement with the corresponding groove is said scale.