US2995823A

US2995823A - Tau-square holder

Info

Publication number: US2995823A
Application number: US822113A
Authority: US
Inventors: Casey E Bowen
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-06-22
Filing date: 1959-06-22
Publication date: 1961-08-15
Anticipated expiration: 1978-08-15

Description

Aug- 15, 1961 c. E. BOWEN 2,995,823

T-SQUARE HOLDER Filed June 22, 1959 2 Sheets-Sheet 1 54555/ ,Hon/EM,

Aug. 15, 1961' c. E. BOWEN 2,995,823

T-SQUARE HOLDER Filed June 22, 1959 2 Sheets-Sheet 2 United States Patent Oce '2,995,823 Patented Aug. 15, 1961 2,995,823 T-SQUARE HOLDER Casey E. Bowen, 520 El Segundo Bldg., Compton, Calif. Filed June 22, 1959, Ser. No. 822,113 3 Claims. (Cl. 33-80) The present invention relates generally to the field of lrafting accessories, and more particularly to a T-square lolder by means of which a conventional T-square may 7e clamped in any desired position on a drafting board vith complete assurance that the elongate rigid portion hereof projecting from the T-square head will at all .imes be in a truly normal position relative to that edge aortion of the board slidably engaged by the head.

Although theoretically the elongate drawing edge porion of a T-square of the structure above mentioned would be normally disposed relative to the edge of the lrafting board contacted by the head, in actual practice .his is not always so. Frequently, and particularly if :he T-square has an elongate straight edge defining mem- :er affixed to the head, relative movement between the read and this member occurs unless the T-square is unuly heavy. Also, occasionally during use the at straight :dge of the head is not in full abutting contact with an edge portion of the drafting board, and as a consequence :he elongate portion of the T-square 'is inaceurately posiioned relative to the drafting board whereby errors creep into the work on the board.

To eliminate the disadvantages of the T-square above described, drafting machines have been designed and marketed in the past wherein two rulers in normal juxtaposition to form an L are at all times maintained in paraltel relationship to edge portions of the drafting board by a. parallelogram linkage mechanism. However, while drafting machines of this type have been found quite satisfactory, they are expensive, heavy and cumbersome to use, and require the utmost care when removed from a. drafting board and stored.

A major object of the present invention is to provide an inexpensive T-square holder that is of extremely simple mechanical structure and when removably mounted on a drafting board, will maintain a T-square in a true normal position relative to two edge portions of the drafting board between which the T-square extends, with the T- square and holder being adapted to be manually moved as an integral unit on the drafting board to any desired position thereon.

A further object of the present invention is to provide an improved T-square holder that is not only adapted to provide the operational advantages above mentioned, but one which may be used with T-squares having elon` gate portions of varying thickness as well as being useable on drafting boards that likewise may be of any thickness within a predetermined range.

Still another object of the invention is to supply a T- square holder which may be actuated to clamp the T- square in a desired position by a simple flick of the linger, and the T-square can be released from the clamped position by substantially the same operation but in a reverse direction.

These and other objects and advantages of a preferred and certain alternate forms of the present invention will become apparent from the following description thereof, and hom the accompanying drawings in which:

` FIGURE 1 is a conventional drafting board on which a T-square is slidably mounted and held in a clamped position thereon by the use of the preferred form of the invention;

FIGURE 2 is a top plan view of the preferred formA of the invention showing a portion of a T-square extending therethrough;

FIGURE 3 is an end elevational view of the holder shown in FIGURE 2;

FIGURE 4 is a vertical cross-sectional View of the holder and T-square taken on line 4-4 of FIGURE 2;

`FIGURE 5 is an exploded perspective view of the T-square holder shown in FIGURES 1-4 inclusive;

FIGURE 6 is a top plan View of rst alternate form of the holder;

FIGURE 7 is a vertical cross-sectional view of the first alternate form of the holder taken on line 7--7 of FIGURE 6;

FIGURE 8 is a top plan view of a second alternate form of holder; and,

FIGURE 9 is a vertical cross-sectional view of the second alternate form of holder taken on line 9-9 of FIGURE 8.

'Ihe preferred form of the T-square holder A, as can best be seen in FIGURE 1, is mounted for slidable movement on one edge portion of a drafting board B to which a sheet of drawing paper C may be affixed by conventional means. A T-square D having a head E and an elongate rigid member F projecting therefrom rests on the drawing board with a straight edge portion of the head abutting against one edge portion of the board and the member F projecting through the holder A.

A handle G forms a part of the holder A, which handle when in the upwardly extending position shown in FIG- URE 3, permits the T-square D and holder A to be shifted along the drafting board B to a desired position thereon. When the desired position is reached, handle G is pivoted downwardly to the substantially horizontal position shown in FIGURE 3, and as a result thereof the T-square is immovably clamped to the drawing boar-dB. If the head E of the T-square D is in full abutment with an edge portion of the board B as such clamping action takes place, the rigid member F will be normally disposed relative to two parallel and laterally separated edge portions B' and B" of the drafting board B.

T-square holder A, as best seen in FIGURES l to 5 inclusive, includes a housing 10 dened by an inverted elongate concave shell 12 that is adapted to be disposed above an edge portion of board B. First and second

parallel end pieces

14 and 16 respectively, preferably formed as integral portions of shell 12, close the ends thereof. A slot 18 extends upwardly in rst end piece 14 (FIGURE 5).

A rectangular flange 20 depends from the outer p0rtion of shell 12. An elongate longitudinally extending opening 22 is formed in ange 20 that is slightly longer than the width of the elongate member F of T-square D that projects therethrough. The height of opening 22 is slightly greater than the thickness of member F, as can best be seen in FIGURE 4. Two longitudinally separated, vertically extending slots 24 are formed in ange 20 below opening 22, and are adapted to have screws 26 extend therethrough. Each screw 26 includes a head 28 and a threaded shank 30. An elongate guide 32 of L-shaped transverse cross section is provided, comprising normally disposed tirst and

second legs

34 and 36 respectively. Two tapped bores 37 are formed in leg 34 that are spaced longitudinally the same distance as slots 24. Bores 37 are threadedly engaged by shanks 30 of screws 26.

vBy vertically adjusting and then tightening the screws 26 in slots 24, guide 32 can be rigidly maintained in a position relative to flange 20 where the interior `face of second leg 36 snugly but slidably engages the lower surface 38 of the drawing board B.

An elongate pressure-applying member K that is actu extending exterior surface, but' the transverse cross section thereof is ofY non-circular configuration. A first end I prion of the body 40 develops into a longitudinally projecting extension 42 thatis pivotally disposed within the confines of slot 18. The outer end of extension 42 develops into the'upwardly projecting handle G. The second end surface 44 of body 40 is at and positioned normally relative to the longitudinal axis of the body. Thensecond end surface 44 of body 40 slidably and rotatably engages the interior surface of the second end piece 1'6. VAtrthe junction thereof, extension 42 and body 40 define a'generally annulus-shaped at surface '45 that is in rotatable and slidable engagement with the interior surface of the first en dY piece 14, as best seen in FIG- URE 2.

The use of the preferred form of the invention is extremely simple. Screws 26 are loosened, and the guide 32 slidably moved on ange 20 to a position where the upper surface of second leg 36 snugly and slidably confacts-the l'owersurface of drawing board B, when the elongate portion `F of T-square D resting on drafting board B is projected Ythrough opening 22, as shown in vFIGURE- 4. The head E of the T-square is placed in full sliding contact with the edge portion B of the board BE Screws Y26 are then tightened to hold guide 32 in the posit-ionv described above. Handle G is pivoted to the upwardly extending position shown in FIGURE 3, whereby the T-square 'D and holder A may be slid longitudinally alongA the drawing board to the desired position. Thereafter handle G may be moved manually in either of; two possible directions to pivot the pressure-applyingy bodyy 40 relative to housing 10. Due to the non-circular cross sectionv of body 40, such pivotal movement forces housing 10, iiange 20, and guide 32 upwardly relative to drawing board portion B", with the second leg 36 and b ody 40 pressure-engaging board B and T-square member -F respectively with sufficient force to hold the T- square D in the desired position on board B.

When it is desired to move the T-square yD on the board B', handle G is simply pivoted from the locking position shown in phantom line in FIGURE 3 to the upright position shown in solid line in the same figure. This movementof handle G permits housing and second leg 3,6 to move downwardly suficiently relative to drafting` board B that no appreciable pressure is applied to T- square Dor the under side of the drafting board whereby the T-square "D and holder A can be slidably moved as an integral unit to a new position thereon. After placement of T-square D and holder A in the new Aposition they may be re-locked in fixed position relative to the drafting board B by manually pivoting handle G into a substantially horizontal position as previously described. A first alternate form of the invention is shown in EIGURES 6 and 7, which is utilized in the same manner as the preferred form and differs structurally therefrom only insofar as that portion thereof situated above the T-square D. Accordingly, the structural elements of the iirst alternate form of the invention below the T- square D are identified by the same numerals used in the description of the preferred form, but to which a prime has `been added.

l 'Ihe first alternate form of the invention includes an inverted semi-cylindrical shell 50, the ends of which are closedz by two identical end pieces 5,2 and `54. A transverse slot 5,6 is formed in the central upper portion of shell 50, as can best be seen in FIGURE 6. An elongate pressure-exerting member 58 is removably disposed within the confines of s hell`50. Member 58 has two identical

circular end surfaces

60 and 62 that are parallel and positioned adjacent the interior surfaces of end pieces 52 and 54 respectively, which are also in parallel relationship. Y

'3A bossr64 extends upwardly from member 58 through slot 56. Boss 64 is slidably movable in slot 56 to permit 4 axial pivotal movement of member 58 within shell 50. A tapped bore 66. extends downwardly in boss 64 and is threadedly engaged by a screw 68 which has a head 70 of greater diameter than the width of slot 56, and thereby prevents member 58 Lfrom-slipping therefrom.

Member 58 is formed withtwo diametrically opposed, longitudinally extending, convex curved exterior cam surfaces 58a and SSb that slidably and rotatably engage the upper surface of T-square. D and the interior surface of shell 50 when member SS- is pivoted. This pivotal movement of member 58 applies a downward force to T- square D and exerts an upwardly directed force on the lower surface of drafting board B through second leg 32 to the extent that the T-square D is removably locked at a desired position on the board.

The second alternate form of the invention shown in FIGURES 8 and 9 is structurally the same as the preferred form below that thereof through which the T- square D extends. The elements comprising the lower structural portion of the second alternate form of the invention are accordingly identified by the same numerals used in designating corresponding parts of the preferred form but to which a double prime has been added.

In FIGURES 8 and 9 it will be seen that an inverted semi-cylindrical housing 70 is provided that is defined by a shell 72 which is closed by identical end pieces 74 and 76. lWhen this second alternate form of the invention is used housing 70 is located above the edge portion B" of the drafting board B. The outer longitudinally extendingedge portion of housing 70 is joined to, or formed as an integral part of flange 20.'. A central downwardly extending tapped bore 78 is formed in shell 72. A screw 80 having a large knurled head 82, threaded shank 84, and downwardlyV extending Unthreaded extension 8S is rotatably supported in Abore 78.

In FIGURES 8 and 9 it will be seen that an elongate pressure applying member 86 is provided that has a curved exterior longitudinal surface. Member 86 has two identical parallel end surfaces 88 and 90 that are positioned adjacent interior parallel surfaces of the end pieces 74 and 76 respectively. A centrally disposed recess 92 is formed in member 86 that is engaged by extension 85. When screw 8l] is rotatedto cause extension to move downwardly relative to housing 70, a downwardly directed force is applied to T-square D by the member 86, and an upwardly directed force is exerted.y

`against the lower surface of drafting board B by the leg 32.". The forces so applied result in the T-square D being removably clamped to the drafting board B in the same manner as in the preferred and iirst alternate forms of the invention.

It will be obvious to those skilled in the art that various changes may be made in my invention without departing from the spirit and scope thereof, and thereforethe invention is not limited by that which is shown in the drawings and described in the specification, but only as indicated in the appended claims.

I claim:

l. A cramping device for holding a T-square having a head from which an elongate rigid member projects at a desired position on a drafting board having iirst and second laterally separated parallel edge portions, comprising: an inverted elongate concave shell; iirst and second parallel end pieces that close the ends of said shell, said. rst end piece having a slot extending upwardly therein; a ange that depends from the outer side portion of saidy shell, which iiange has an opening formed therein that is slightly wider than the width of said elongate member to permit apart of said elongate member to extend therethrough and slightly deeper than the thickness. of said elongate member; an elongate guide of L-shaped transvers cross section; means for adjustably supporting said guide from sad flange; an elongate pressure-apply- 3 are disposable adjacent the interior surfaces of said first and second end pieces when said pressure-applying member is situated in said shell; said pressure applying member having an extension that projects through said slot in said rst end piece and is rotatable relative thereto; and means rigidly connected to said extension and disposed exterior-ly of said shell that is operable by the hand of a user when resting on said shell for pivoting said pressureapplying member in said shell to a position where said elongate member of said T-square and second board edge portion are frictionally gripped between said pressureapplying member and said guide to prevent movement of said T-square relative to said board until said hand operated means is actuated to pivot said pressure-applying member to a position where said elongate member and second board edge portion are not frictionally gripped.

2. A clamping device as defined in claim l wherein said hand-operated means is an elongate handle that extends outwardly from said extension and normal thereto.

3. A clamping device for holding a T-square having a head from which an elongate rigid member projects at a desired position on a drafting board having iirst and second laterally separated parallel edge portions, comprising: an inverted elongate concave shell; rst and second parallel end pieces that close the ends of said shell, a

flange that depends from the outer side portion of said shell, which ange has an opening formed therein that is slightly wider than the Width of said elongate member and slightly deeper than the thickness of said elongate member to permit a part of said elongate member to extend therethrough an elongate guide of L-shaped transverse cross section; means for adjustably supporting said guide from said flange; an elongate pressure-applying member of generally elliptical transverse cross section that has rst and second flat parallel end portions that are disposable adjacent the interior surfaces of said iirst and second end pieces when said pressure-applying member is situated in said shell; hand-operated means extending upwardly from said pressure-applying member through a transversely disposed slot formed in the upper portion of said shell for rotating said pressure applying member in said shell.

References Cited in the tile of this patent UNITED STATES PATENTS 1,121,512 Krause Dec. 15, 1914` 1,130,926 Peck Mar. 9, 1915 FOREIGN PATENTS 326,069 Germany Sept. 22, 1920 UNITED STATES PATENT OEEICE CERTIFICATE OF CORRECTION Patent No, 2,995 823- August 15, 1961 Casey E. Bowen It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below..

Column 4, line 59, for "campingn read clamping Signed and sealed this 19th day of December 1961.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer l Commissioner of Patents