US3768166A

US3768166A - Drawing instruments

Info

Publication number: US3768166A
Application number: US00251617A
Authority: US
Inventors: P Elliott
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-05-08
Filing date: 1972-05-08
Publication date: 1973-10-30
Anticipated expiration: 1990-10-30

Abstract

A drawing instrument is provided with integral legs joined at one end which may be pinned together on a co-acting pivot center at the joined end and which may further include rotatable journal elements mounted to the legs for adjustment of the legs by threaded shafts associated with a thumbwheel.

Description

United States Pate 11 1 El i t 1 1 01:11. 30, 1973 1 DRAWING INSTRUMENTS 3,208,149 9/1965 Zachs 33 157 [76] lnvent or: Phillip Mitchell Elliott, 411 N. 7th FOREIGN PATENTS OR APPLICATIONS SL1 Park 63101 356,998 8/1922 Germany 33/153 A 22 Filed; May 8, 1 2 176,441 10/1906 Germany...

467,610 10/1928 Germany 33/154 F [21] Appl. No.: 251,617

Primary Examiner-Harry N. Haroian 521 1U.s.c|...' 33/27 B, 33/153 R, 33/154 F ArwmeyMichael Kovac [51] Int. Cl B43l 9/20 [58] Field of Search 33/27-B, 154 F, 152 B, 57 ABSTRACT 33/153 A A drawing instrument is provided with integral legs [56] References Cited joinedat one end which may be inned together on a co-actlng pivot center at the oined end and which UNITED STATES PATENTS may further include rotatable journal elements 2,297,999 10/1942 Eubanks 33/154F mounted to the legs for adjustment of the legs by 313-275 3/1885 Barber 1 33/154 F threaded shafts associated with a thumbwheel. 2,557,500 6/1951 Fairbanks... 33/22 B 953,026 3/1910 Evans 33/152 B 117 Claims, 15 Drawing Figures DRAWING INSTRUMENTS SUMMARY OF THE INVENTION In the manufacture of drawing instruments such as compasses for todays markets, it has been a practice to produce different compasses for specific market requirements. The professional market requires a very precise instrument which is relatively costly as compared with the inexpensive and precise instrument that is currently available for the school market. As is well known, compasses for the school market do not require the durability or operating features of the compasses used for the professional market; however, there has been little success in producing a relatively inexpensive compass which gives good operation and adjustment features over a reasonable period of time for the school market. Also, while compasses for the professional market do provide the durability and operating features that are necessary, they are nonetheless more expensive than is desired.

Accordingly, it is an object of the present invention to provide a new and improved drawing instrument for the school and/or professional market.

Another object of the present invention is to provide a drawing instrument such as a compass which is relatively inexpensive in comparison to prior artdesigns.

A still further object of the present invention is to provide a drawing instrument such as a compass which, in addition to the aforementioned objects, is durable and has good operating characteristics.

These and other objects and advantages of the present invention are attained by providing a drawinginstrument including a spring bow section and integral legs depending therefrom, the legs being pinned together on a co-acting pivot center immediately adjacent the spring bow section. The drawing instrument may further include rotatably mounted journal elements associated with the legs which cooperate with a thumb-wheel having oppositely threaded shafts which threadably engagethe rotatable mounted journal elements.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sideelevational viewof one form of drawing instrument which is constructed in accordance with the teachings of the present invention;

FIG. 2 is an end elevational view of the instrument shown in FIG. 1 as viewed from the right-hand side thereof;

FIG. 3 is an end elevational view of the instrument shown in FIG. I as viewed from the left-hand side thereof;

FIG. 4 is a fragmentary enlarged perspective view of the upper portion of the instrument depicted in FIGS. l-3;

FIG. 5 is an enlarged fragmentary sectional view of the frangibly connected pivot pin associated with the drawing instrument of FIGS. 1-4;

FIG. 6 is a fragmentary sectional view, on a slightly smaller scale, illustrating the assembly of the pivot pin to the drawing instrument;

FIG. 7 is a side elevational view of the drawing instrument illustrated in FIGS. 1-6 including all the components thereof;

FIG. 8 is a side elevational view of a modified form of drawing instrument including all components thereof;

FIG. 9 is a side elevational view of the drawing instrument depicted in FIG. 8 prior to the assembly of all the components thereof;

FIG. 10 is a side elevational view of yet another modified form of drawing instrument illustrating the manner of injection molding a plurality of components together;

FIG. 11 is an end elevational view of the modified form of compass shown in FIG. 10;

FIG. 12 is an enlarged fragmentary perspective view depicting a frangibly connected journal element which is associated with the modified compass shown in FIGS. 10-11;

FIG. 13 is an enlarged exploded end elevational view of the frangibly connected journal element area of the compass shown in FIGS. 10-12;

FIG. 14 is an enlarged fragmentary end elevational view of the releasable locking means for the elongated marking element associated with the compass design of FIGS. 10-13;

FIG. 15 is an enlarged exploded side elevational view of the releasable locking area shown in FIG. 14 of the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS While the drawing instrument shown in the drawings is representative, as it will be apparent that the various designs illustrated may also be used for divider instruments and other compass designs with or without a thumb-wheel adjustment, as may be desired.

Reference isfirst made to tlie embodiment shown in FIGS. 1-7 of the drawings. It will be seen from FIGS. 1-3 that the compass 10 is integrally molded from suitable plastic material as a one-piece compass body having a stem or handle 12, a spring bow section 14 and integral legs 16-18 depending from the spring bow section 14. The stem 12 is centrally located of the spring bow section 14 to facilitate proper balanced and manipulative movement of the compass 10. The spring bow section 14 has a generally inverted U-shaped configuration which is connected to the

integral legs

16, 18 so as to normally urge them apart from one another as is illustrated in FIG. l. I

On the insideof each

leg

16, 18 in the area of juncture with the spring bow section 14, there are

ear portions

20, 22 respectively which are capable of interfitting with one another. Specifically, and as best seen in FIGS. 1 and 4-6, the

ear portions

20, 22 are provided with

mating openings

24, 26 respectively into which a pivot pin 28 is driven when the

mating openings

24, 26 of the

ear portions

20, 22 respectively are aligned with one another. This is achieved by closing the normally urged apart

legs

16, 18 until the

mating openings

24, 26 are aligned at which point the pivot pin 28 may be driven into the openings. The assembly of the pivot pin 28 relative to the

mating openings

24, 26 is best illustrated in FIG. 6 of the drawings.

It will be noted, as best seen in FIGS. 2 and 4-5, that the pivot pin 28 is initially frangibly connected to the ear portion 20 by a thin connecting web 30. This construction facilitates the molding of the compass body and permits the pivot pin 28 to be properly positioned for assembly through the

mating openings

24, 26 when aligned with one another. A simple blow from a hammer separates the pivot pin 28 from the ear portion 20 and allows it to be inserted within the

mating openings

24, 26 respectively.

It will be noted, particularly from FIG. 5 of the drawings, that the mating opening 26 is smaller than the mating opening 24 and has a lead-in portion 32 which tapers inwardly from the opening 24 to the opening 26. The dimensions of the

openings

24, 26 relative to the pivot pin 28 is such that the pivot pin has a forced fit relationship with respect to the mating opening 26 while having a loose fitting relationship to the mating opening 24. This is important because the pivot pin 28 must be securely retained in the

ear portions

20,22, and yet provide relative rotating movement of the

ear portions

20,22 and the

corresponding legs

16, 18 with respect to one another. This is made possible by the loose fitting relationship of the pivot pin 28 relative to the mating opening 24 and the forced fitting relationship of the pivot pin 28 relative to the mating opening 26 of the

ear portions

20, 22 respectively. Thus, there is provided a tightly secured pinned hinge axis for the compass pin when the aforementioned assembly is made.

It will be noted that complementary shaped

portions

34, 36 are provided on the inside of the

compass legs

16, 18 for receiving the

cars

20, 22 respectively when the pivot pin 28 is assembled through the

mating openings

24, 26 thereof. These complementary shaped portions facilitate predetermined rotary or hinging movement of the

ear portions

20, 22 and

corresponding legs

16, 18 relative to one another.

Each of the

legs

16, 18 includes an

upper segment

38, 40 respectively which extends downwardly and outwardly from the spring bow section 14 and

lower leg segments

42, 44 respectively which extend downwardly and inwardly from the

upper leg segments

38, 40 respectively. These leg configurations aid in permitting complete closing of the

legs

16, 18 while allowing a greater amount of lead or other marking element to be mounted in the compass, as will become apparent. Each of the

legs

16, 18 also includes an

opening

46, 48 respectively for receiving rotatably mounted journal elements as will be described below.

The configuration of leg 16 is best illustrated in FIG. 2 of the drawings. There, it will be seen that the upper and

lower leg segments

38, 42 respectively are offset from one another as at 50, in addition to their having the inclination shown in FIG. 1 of the drawings. Further, the lower leg segment 42, while being downwardly and inwardly directed relative to the upper leg segment 38 as shown in FIG. 1, is also configured to taper or incline from the offset portion 50 to the lower free end thereof where the spiral pin 52 is provided. This construction of the leg 16 conserves on material and provides the arrangement that is desired.

In FIGS. 1 and 3 of the drawings, of the leg 18 is best shown. In addition to the inclination of the upper and

lower leg segments

40, 44 with respect to one another, the leg 18, as best seen in FIG. 3 of the drawings, has a slight bow from the top to the bottom thereof. The leg 18 is also provided with an elongated slot 54 which extends throughout the entire height of the lower leg segment 44 for receiving lead or other marking element which is much longer than is normally possible. The elongated slot 54 traverses a flexible wing element 56 which is attached to the lower segment 44 of the leg 18 and is capable of being moved into and out of locking engagement relative to the lead or marking element (not shown). Aligned

openings

58, 60 are provided in the flexible wing 56 and lower segment 44 of the leg 18 for reception of a locking element, as will presently be described.

Reference is now made to FIG. 7 of the drawings which shows a completely assembled compass 10 including a thumb-wheel 62 with oppositely threaded

shafts

64, 66 which are threadably associated relative to the rotatably mounted

journal elements

68, 70, and a bolt element 72 which extends through the opening 58 of the wing element 56 into the opening 60 of the lower leg segment 44. The rotatably mounted journal element 68, are mounted within the

openings

46, 48 of the

legs

16, 18 respectively and include threadable openings (not shown) which respectively engage the oppositely threaded

shafts

64, 66 associated with the thumb-wheel 62. Thus, as the thumb-wheel is rotated the oppositely threaded

shafts

64, 66 threadably engage the rotatably mounted

journal elements

68, 70 for moving the

legs

16, 18 relative to one another. The

legs

16, 18 are pivotally mounted or hinged about the pivot pin 28 which provides a tightly pinned joint for the

legs

16, 18 yet also provides through the spring bow section 14 a damping spring force. This construction provides a stable arrangement with respect to both spreading and closing forces that may be applied to the

legs

16, 18 so that the legs are precisely held at whatever radius is set while drawing. This is important since the compass 10 can thus resist any push or pull forces imposed on the leg 18 carrying the marking element during drawing. The tightly pinned joint for the

compass legs

16, 18, coupled with the damping spring force against the

legs

16, 18, maintains the

legs

16, 18 in the position which has been preset by the thumb-wheel 62.

In order to provide complete closing of the

compass legs

16, 18 the inside of the

legs

16, 18 are provided as at 74, 76 with complementary configured and sized cut-out sections for receiving the thumb-wheel 62. The bolt element 72 is designed to engage the flexibly mounted wing element 56 for moving the wing element 56 into and out of locking engagement relative to the piece of elongated lead or other marking element positioned in the elongated slot 54.

Reference is now made to the other embodiments of the invention herein disclosed where like parts are identified by the same reference numerals with alphabetical suffixes being used in consecutive ordr to distinguish from the various embodiments.

In the embodiment illustrated in FIGS. 8-9, the compass 10a is similar to the compass 10 shown in FIGS. 1-7 with the exception of the generally centrally located beam or projection 78 which is integrally attached to the spring bow section 14a in the area of the stem 12a, but on the opposite side thereof. The beam or projection 78 includes at the lower end thereof an elongated opening 80 which is adapted to cooperate with the mating openings 24a, 26a of the

interfitting ear portions

20a, 22a. The beam or projection 78 is adapted to be positioned between the

interfitting ears

20a, 22a such that when the legs 16a, 18a are closed to bring the mating openings 24a, 26a into alignment with one another, the mating openings 24a, 26a will also be aligned with the elongated opening 80 in order that the pivot pin 28a can be assembled through the mating openings 24a of the interfitting ear 20a, the elongated opening 70 of the beam or projection 78, and the mating opening 26a of the interfitting ear 22a.

This construction causes the pivot pin 28a to move substantially vertically within the elongated slot 80 during opening and closing of the legs 16a, 18a without any lateral or horizontal movement thereof. Thus, the tightly pinned joint of the compass legs 16a, 18a can be further restrained against any horizontal or lateral movement of the legs 16a, 18a that is not caused by the thumb-wheel 62a moving the legs 16a, 18a toward and apart from one another, as may be desired.

Reference is now made to the compass embodiment b illustrated in FIGS. 10-15 of the drawings. From the discussion that is to follow, it will be seen that the compass 10b has been constructed in order to provide integral molding of a number of the elements of the compass as a whole.

Thus, it can be seen from FIGS. 10-11 that the compass 10b includes a stem 12b with integral compass legs 16b, 18b, each of which have frangibly connected journal elements 68b, 70brespective1y. In addition to the flexible wing 56b construction at the lower end of leg 18b, thethumb-wheel 62b with oppositely threaded

shafts

64b, 66b are integrally connected to the bolt element 72b and are arranged to be integrally molded relative to the remainder of the compass body. The construction and arrangement of the above described parts makes it possible to provide for simple two-plate injection molding without side cores. Further, as only several additional parts will be required to provide an operating compass as will be seen, the construction is quite economical.

It will be noted that each of the legs 16b, 18b have a T-shaped construction wherein the

upper leg segments

38b, 40b are inverted relative to the

lower leg segments

42b, 44b. Specifically, the

cross bar

82, 84 of the T- shaped legs 16b, 18b is on the inside of the compass legs 16b, 18b in the

upper leg segments

38b, 40b while being arranged on the outside of the legs 16b, 18b in the

lower leg segments

42b, 44b. Similarly, the foot or

extension

86, 88 of the T-shaped construction of the legs 16b, 18b is on the inside of the legs in the

lower leg segments

42b, 44b while being arranged on .the outside 1 of the legs in the upperleg segment 38b, 40B. The T- shaped construction of the legs 16b, 18b minimizes the use of material and yet: provides a strong and durable leg construction.

Each of the journal elements 68b, 70b are frangibly connected to the journal mounts 90, 92 respectively which are integrally molded in the T-shaped leg construction in the vicinity of the juncture of the

upper leg segments

38b, 40b with the

lower leg segments

42b, 44b. This is best illustrated in FIGS. 10-13 of the drawlngs.

The specific construction of the journal elements and their relationship to the journal mounts can best be understood by referring to FIGS. 12-13 of the drawings which illustrate the journal element 70b relative to the journal mount 92 of the compass leg 18b. As can be seen, the journal 70b is integrally attached within the journal mount 92 at 94. Thus, in separating thejournal element 70b from the journal mount 92b by a hammer blow or the like, the journal element 70b is designed to be properly positioned within the journal mount 92. It will be seen that the journal element 70b includes an end opening 96 for receiving the nut element 98 therein. When the nut element 98 is mounted in the end opening 96, as can be seen in FIG. 13 of the drawings, the threaded opening 100 of the nut element 98 communicates with the side opening 102 of the journal element 70b which also communicates with the slot 104 formed in the journal mount 92 of the leg 18b when the journal element 70b is assembled relative to the journal mount 92. Thus, the threaded shaft 66b associated with the thumb-wheel 62b can be positioned through the slot 104 of the journal mount 92, and the side opening 102 of the journal element 70b for threaded engagement with the threaded hole 100 of the nut element 98 positioned within the end opening 96 of the journal element 70b.

The result is that in assembling the thumb-wheel 62 with its threaded

shafts

64b, 66b to the journal elements 68b, 70b of the legs 16b, 18b respectively, it is only necessary to frangibly disconnect the journal elements 68b, 70b and position the journal elements 68b, 70b within their respective journal mounts 90, 92, and then insert separate nut elements within the journal elements for threaded engagement with the threaded

shafts

64b, 66b associated with the thumb-wheel 62b. Similarly, it is a relatively simple matter to assemble the bolt element 72b to the leg 18b for releasable locking engagement with an elongated marking element (not shown) which is received within the elongated slot 54b. This is best seen in FIGS. 14-15 of the drawings where the leg 18b is provided with an opening 106 which receives a separate nut element 108 having a threaded hole 110 which threadably engages the bolt element 72b for moving the flexible wing element 56b into and out ofreleasable locking engagement relative to an elongated marking element (not shown) positioned within the elongated slot 54b.

The FIGS. 10-15 embodiment thus utilizes a mini mum number of separate parts and conserves on material to provide an economical, yet good operating compass. All of the parts except for the three nut elements used with the two journal elements 68b, 70b and the bolt element 72b and a separate spiral pin for attachment to the lower end of leg 16b, can be integrally molded together as best illustrated in FIG. 10 of the drawings. g j l From the foregoing, it will now be appreciated that the herein disclosed embodimentsof the present invention provides a new and improved drawing instrument which can be used for the school and/or professional market. Some of the features shown in the various embodiments may be combined or used separately, as may be desired. Thus, the spring bow section 14 shown in the FIGS. 1-9 embodiments may be used in the FIGS. 10-15 embodiment if desired. Similarly, the T-shaped construction of the legs shown in the 10-15 embodiment may be usedwith or without the frangibly connected journal elements in the FIGS. 1-9 embodiment. Accordingly, it will thus be apparent that the present invention contemplates many design possibilities without sacrificing durability or good operating characteristics.

I claim:

1. A drawing instrument including a spring bow section and integral legs depending therefrom which are normally urged apart by the spring bow section, said legs being pinned together immediately adjacent the spring bow section by common pivot means when the toward and away from one another about the common pivot means.

2. The device as defined in claim 1 wherein the interfitting ear portions are each received within complementary shaped portions in the vicinity of the common pivot means.

3. The device as defined in claim 1 wherein the common pivot means further includes a pivot pin which is associated with the interfitting ear portions.

4. The device as defined in claim 2 wherein the pivot pin is at least initially integral with one of the interfitting ear portions.

5. The device as defined in claim 3 wherein the pivot pin when assembled to the interfitting ear portions engages one of said interfitting ear portions in forced fitting relationship and the other of said interfitting ears in loose fitting relationship.

6. The device as defined in claim 3 wherein the pivot pin is mounted for movement within a substantially vertically directed elongated opening formed in a generally centrally located integral projection depending from the spring bow section.

7. The compass as defined in claim 1 wherein the means for moving the legs toward and away from one another includes a thumb-wheel with oppositely threaded shafts which threadably engage rotatably mounted journal plate elements associated with the legs.

8. The device as defined in claim 7 wherein each of the legs is provided with a cutout section which is complementarily configured and sized relative to the thumb-wheel for receiving the same therein when the legs are in close proximity to one another.

9. The device as defined in claim 1 wherein each of said legs includes upper segments which extend downwardly and outwardly from the spring bow section and lower segments which extend downwardly and inwardly from the upper segments.

10. The device as defined in claim 9 wherein at least one of the lower segments on said legs includes an elongated slot which extends throughout the entire height thereof for receiving an elongated marking element.

11. The device as defined in claim 10 including means associated with the elongated slot for releasably locking an elongated marking element therein.

12. The device as defined in claim 11 wherein the means for releasably locking the elongated marking element includes a flexible wing attached to the lower segment of the leg agjacent the elongated slot which is capable of being moved into and out of locking engagement relative to the elongated marking element.

13. The device as defined in claim 16 wherein the flexible wing is moved by a bolt element which extends through the wing element and engages a nut element mounted to the lower segment of the leg on the other side of the elongated slot.

14. The device as defined in claim 7 wherein the rotatably mounted journal elements are initially integrally connected to the legs.

15. The device as defined in claim 14 wherein the rotatably mounted journal elements have an end opening for receiving a nut element therein and a side opening which communicates with the hole of the nut element and a slot formed in the leg element for receiving one of threaded shafts associated with the thumb-wheel.

16. The device as defined in claim 9 wherein each of the legs have a T-Shaped construction.

17. The device as defined in claim 20 wherein the T- Shaped construction of said legs is inverted on said upper and lower segments of each leg.

Claims

1. A drawing instrument including a spring bow section and integral legs depending therefrom which are normally urged apart by the spring bow section, said legs being pinned together immediately adjacent the spring bow section by common pivot means when the spring bow section is placed under compression, said common pivot means including interfitting ear portions provided on said legs, and means for moving the legs toward and away from one another about the common pivot means.

17. The device as defined in claim 20 wherein the T-Shaped construction of said legs is inverted on said upper and lower segments of each leg.