US3301480A

US3301480A - Slide rule cursor

Info

Publication number: US3301480A
Application number: US481641A
Authority: US
Inventors: Muller Friedrich
Original assignee: Dennert and Pape Aristowerke KG
Current assignee: Dennert and Pape Aristowerke KG
Priority date: 1964-08-29
Filing date: 1965-08-23
Publication date: 1967-01-31
Anticipated expiration: 1984-01-31
Also published as: DK108994C; GB1039127A; DE1264828B

Description

Jan. 31, 1967 F. MULLER ,301,480

SLIDE RULE CURSOR Filed Aug. 23, 1965 2 Sheets-Sheet l H wllllliilmauyfl L 1mg;

IIIAVIVil INVENTOR d rr'aj r- F. MULLER Jan. 31, 1967 INVENTOR fiea rxy h United States Patent assignor Hamburg- The present invention relates to a slide rule cursor comprising at least one transparent plate which at two oppositely located substantially parallel edges is respectively provided with guide bars. These guide bars have those sides thereof which face each other designed as guiding surfaces for engagement with the slide rule, while one of said guide surfaces is equipped with spring means for engagement with the slide rule.

Slide rule cursors of this type as heretofore known have said spring means formed by a flat elongated metal tongue which is connected to one of the guide bars. The assembly and connection of such metal spring means to the respective guide bar necessitates a special operation and in addition thereto requires a certain amount of care in order to assure that the marks on the curs-or will run parallel to those on the graduated scale.

It is, therefore, an object of the present invention to provide a slide rule cursor in which the provision of the spring means on the respective guide bar will be greatly simplified.

It is another object of this invention to provide a slide rule cursor as set forth above, which will not require a special assembly operation for arranging the spring means on the respective guide bar.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawings, in which:

FIG. 1 is a transverse section through a slide rule cursor according to the present invention. I

FIG. 2 is a top view of the slide rule cursor of FIG. 1,

however, with the upper reading window removed therei from.

FIG. 3 is a section along the line III-III of FIG. 1 but with the upper window mounted thereon.

The slide rule cursor according to the present invention is characterized primarily in that the spring means on the guide bars of the cursor do not represent separate elements connected to the respective guide bar by screws or other fastening means but form a single integral piece with the respective guide bar. In other words, when the guide bar is produced the spring means is either worked out of the guide bar by a cutting operation or the like or the spring means is simultaneously molded with the respective guide bar. In this 'way, no special assembly and aligning operations are necessary for the spring means thereby greatly simplifying the manufacture of the slide rule cursor. Moreover, there is no danger that the spring means get-s loose with regard to the guide bar.

Referring now to the drawings in detail, the slide rule cursor shown therein is intended for two-sided slide rules. It is for this reason that the slide rule cursor, generally designated 10, has two reading windows 11 and 12 held at the required distance from each other, in conformity with the thickness of the slide rule, by substantially

parallel guide bars

13 and 14 at the side portions of the windows. Since the ends of two-sided slide rules are in the vast majority of cases provided with cross bars, the cursor cannot be mounted on the slide rule by slipping it on from one end. For this reason, slide rules of this type are provided with means which permit the taking 011 of one of the reading windows. With the specific slide rule cursor according to the present invention, the reading window 12 is detachably connected to guide bar 14. To this end, guide bar 14 has at least one bore 19 therethrough in which is arranged a collar-shaped resilient means 20. In contrast to heretofore known arrangements of the type involved in which a ring was provided with a slit and in-- jected into a bore, means 20 in bore 19 according to the present invention is formed merely by a metal-free collar-shaped constriction of relatively short axial length, which make-s it possible to detachably receive and lock a stud 23 in a push button-like manner, as shown in FIG. 3, according to which push button 23 extends through a bore 12a in window 12 and has its lower end 23b snapped in collar-shaped resilient means 20. The same type of snap fastener is employed at both ends of window 12 to connect it to both of

bars

13 and 14. The guide bar 14 is of the customary shape. In order to assure a precise support of the slide rule cursor along the sides of the slide rule, the ends only of guide bar 14 are designed as guiding surfaces 22, whereas the adjacent surface area 21 between sliding and guiding surfaces 22 is recessed so as not to contact the slide rule when the cursor is mounted thereon. As will be seen from the drawing, especially FIG. 3, reading window 11 is connected to

guide bars

13 and 14 by means of

screws

24 and 25 respectively engaging correspondingly threaded

bores

26 and 27 in the guide bars. FIG. 3 shows guide bar 14 but guide bar 13 is identical thereto with respect to the fastening of the reading windows to the bars. According to a particularly advantageous embodiment of the present invention, one of the reading windows may be made of one and the same piece with one of the guide bars, for instance, guide bar 14 so that no screw connection between the window 11 and the guide bar 13 is necessary.

In order to assure that the cursor be as evenly supported as possible on the body of the slide rule, it is advisable to provide the cursor with spring means, generally designated 15, said spring means preferably comprising two

tongues

16, 16a having their free ends extending in opposite directions, i.e. in the approximate transverse direction of the cursor while being located slightly be neath the top and bottom surfaces of the guide bar 13.

Tongues

16, 16a preferably extend from the center portion of the guide bar 13 while confining with each other an obtuse angle. Preferably, the free ends of the tongues are provided with foot-shaped surfaces located parallel to the direction of displacement of the cursor. The free ends of the resilient tongues extend slightly beyond the adjacent external end surfaces of guide bar 13 in the direction toward the guide bar 14.

The guide bars of the cursor may be of any suitable material which has adequate anti-friction properties as for instance a plastic material produced by the polymerization of anhydrous formaldehyde with about 1500 formaldehyde units to the molecule. Such a material is known, for instance, under the trademark Delrin produced and marketed by Du Pont. Also material such as the material known under the trademark Teflon is suitable for the guide bars according to the invention.

The spring means 16, 16a may be molded simultaneously with and of the same material as guide bar 13. However, if desired, the spring means 16, 16a together with the guide bar 13 may first be molded as a single solid piece whereupon slits 17 are machined into the thus It is, of course, to be understood that the present invention is, by no means, limited to the particular arrangement shown in the drawings but also comprises any modifications within the scope of the appended claims.

-What I claim is:

1.v A slide rule cursor which includes: at least one transparent plate forming a sight window, first rail means arranged adjacent to one end face of said plate and provided with a guiding surf-ace for sliding engagement with one side surface of a slide rule, and second rail means of polymer plastic material arranged adjacent to the other end face of said plate opposite said first nail means so that one side of said second rail means faces said first rail means, said second rail means having a guiding surface at each end facing said firs-t rail means, said second rail means having a slot extending from inwardly of each guiding surface :laterally and at an angle to the surface toward the center of said rail means, said slots defining tongues forming an obtuse angle between said guiding surfaces on the side of said second rail means facing said first rail means with their ends closer to said first rail means than said guiding surfaces, so that said tongues will resiliently engage the side of said rule under tension when 4, in position on said rule, and a second plate fixed to the opposite sides of said rail means.

2. A slide rule according ,to claim 1, in which said second plate is detachably secured to said rail means by a resilient snap fastener at each end.

References Cited by the Examiner UNITED STATES PATENTS 1,021,484 3/1912 Richardson 235- 2,173,459 9/1939 van Doormaal 235-70 2,334,725 11/1943 Perkins 235 7o.2 2,486,748 11/1949 Koenig 235-70 2,968,438 l/l96l Bachmann et al 23570.2 3,047,222 7/196'2 Kasmann 235 70.2 3,195,813 7/1965 Hart 235 FOREIGN PATENTS 583,637 12/1946 GreatBritain.

RICHARD B. WILKINSON, Primary Examiner.

LOUIS J. CAPOZI, Exa'miner.

JAMES G. MURRAY, Assistant Examiner.

Claims

1. A SLIDE RULE CURSOR WHICH INCLUDES: AT LEAST ONE TRANSPARENT PLATE FORMING A SIGHT WINDOW, FIRST RAIL MEANS ARRANGED ADJACENT TO ONE END FACE OF SAID PLATE AND PROVIDED WITH A GUIDING SURFACE FOR SLIDING ENGAGEMENT WITH ONE SIDE SURFACE OF A SLIDE RULE, AND SECOND RAIL MEANS OF POLYMER PLASTIC MATERIAL ARRANGED ADJACENT TO THE OTHER END FACE OF SAID PLATE OPPOSITE SAID FIRST RAIL MEANS SO THAT ONE SIDE OF SAID SECOND RAIL MEANS FACES SAID FIRST RAIL MEANS, SAID SECOND RAIL MEANS HAVING A GUIDING SURFACE AT EACH END FACING SAID FIRST RAIL MEANS, SAID SECOND RAIL MEANS HAVING A SLOT EXTENDING FROM INWARDLY OF EACH GUIDING SURFACE LATERALLY AND AT AN ANGLE TO THE SURFACE TOWARD THE CENTER OF SAID RAIL MEANS, SAID SLOTS DEFINING TONGUES FORMING AN OBTUSE ANGLE BETWEEN SAID GUIDING SURFACES ON THE SIDE OF SAID SECOND RAIL MEANS FACING SAID FIRST RAIL MEANS WITH THEIR ENDS CLOSER TO SAID FIRST RAIL MEANS THAN SAID GUIDING SURFACES, SO THAT SAID TONGUES WILL RESILIENTLY ENGAGE THE SIDE OF SAID RULE UNDER TENSION WHEN IN POSITION ON SAID RULE, AND A SECOND PLATE FIXED TO THE OPPOSITE SIDES OF SAID RAIL MEANS.