US3756637A

US3756637A - Snap track

Info

Publication number: US3756637A
Application number: US00204620A
Authority: US
Inventors: T Wildi
Original assignee: LAB VOLT Ltd
Current assignee: LAB VOLT Ltd
Priority date: 1971-12-03
Filing date: 1971-12-03
Publication date: 1973-09-04
Anticipated expiration: 1990-09-04
Also published as: CA974037A

Abstract

A snap trac comprising a track adapted to be secured to a supporting surface and having at least one side flange bent upwardly at a predetermined acute angle from the plane of the supporting surface, and a leaf spring also secured to the supporting surface and projecting upwardly from the plane of the supporting surface at an angle slightly less than the angle of the flange of the track. A base adapted to support an object is provided with a dovetail slot and has one wall of such slot arranged to engage the flange of the track and the other wall thereof arranged to engage the leaf spring so as to be firmly snapped on the track and against the supporting surface by the force of the leaf spring acting on such other wall of the dovetail slot in the base.

Description

United States Patent [191 Wildi [451 Sept. 4, 1973 [54] SNAP TRACK 3,253,251 5/1966 Norden 339/198 GA 66 9 [75] Inventor: Theodore Wildi, Quebec City, 3259876 7/19 Nome 339/1 8 GA Quebec Canada Primary Examiner-William H. Schultz [73] Assignee: Lab-Volt (Quebec) Limited, Quebec, A rney-Raymond A. Robic Canada [5 7] ABSTRACT [22] Filed Dec. 1971 A snap trac comprising a track adapted to be secured [21] Appl. No.: 204,620 to a supporting surface and having at least one side flange bent upwardly at a predetermined acute angle [52] Us. Cl 287/189 36 M 248/223 339/198 GA from the plane of the supporting surface, and a leaf [51] Int CL Fmm 13/00 spring also secured to the supporting surface and pro- [58] Fieid "248/73 jecting upwardly from the plane of the supporting sur- 339/l9"8- M 36 face at an angle slightly less than the angle of the flange of the track. A base adapted to support an object is pro- [56] References Cited vided with a dovetail slot and has one wall of such slot arranged to engage the flange of the track and the other UNITED srliATEs PATENTS wall thereof arranged to engage the leaf spring so as to 3,175,031 3/1965 Remer 248/223 X be snapped on the track and against the supportgz k ing surface by the force of the leaf spring acting on such u 3,239,182 3/1966 Blanz 248/223 (her wall of the doveta Slot the base 2,754,974 7/1956 Larson 248/223 UX 7 Claims, 4 Drawing Figures 20 ll J! b i L I V SNAP TRACK This invention relates to a snap track for mounting objects, and more particularly for mounting electrical and mechanical components in electrical work.

Educational bread-boarding often requires the mounting of components such as switches, resistors, relays, pneumatic plungers, hydraulic pumps, and fluidic components etc., on a flat base. The mounting means is influenced by the weight of the components, by the forces which may act on them, and the ease with which they may be added or removed from a set up. Accordingly, in the known mounting means, the mounting has been done by using bolts, peg-boards, meshed fabric, clamps and so forth.

It is the object of the present invention to provide a snap track permitting to hold a number of compoennts firmly in place without the use of bolts or other similar fastening means.

It is a further object of the invention to provide a snap track permitting sliding movement of the components on the track while they are still firmly retained in place.

The snap track, in accordance with the invention, comprises a track adapted to be secured to a supporting surface and having at least one side flange bent upwardly at a predetermined acute angle from the plane of the supporting surface, and a leaf spring also secured to the supporting surface and projecting upwardly at an angle slightly less than the angle of the flange. A base is adapted to be mounted on the supporting surface and has a dovetail slot therein, one wall of which is sloped by the same angle and adapted to contact the flange, and the other wall which is adapted to contact the leaf spring so as to be snapped firmly on the track and against the supporting surface by ,the force of the leaf spring acting on such other wall of the dovetail slot in the base.

The track and the leaf spring may be of any desired length for mounting a number of bases thereon. The above mounting permits the base to slide on the track while being firmly retained in place. However, if it is required to hold the base at a predetermined position, slots may be provided along the flange of the track and a corresponding ridge inside the undercut portion of the base so as to prevent-sliding of the base on the track.

The above-described bread-boarding system offers the following advantages:

l. The components can easily be added or removed from the experimental set up. I

2. The components cannot he accidentally shaken loose or knocked out of their support.

3. The components are mechanically held in such a way that they always lie flat and hard against the supporting surface. I I

4. The components are mechanically held so that there is only one degree of freedom (they may slide along the track) and all other tolerances are held to close limits. This feature is particularly important where individual components must be mechanically linked by levers, by gears, by pistons or by other means.

The invention will now be disclosed with reference to a preferred embodiment thereof and to the accompanying drawings in which:

FIG. 1 illustrates a perspective view of a snap track in accordance with the invention;

FIG. 2 illustrates how a base is secured to the snap track;

FIG. 3 illustrates a section through the snap track of FIG. 1 as well as forces acting on the base when it is secured to the snap track; and

FIG. 4 illustrates an alternative embodiment of the snap track.

Referring to FIG. 1 of the drawings, there is shown a supporting surface in the form of a plate 10 upon which is mounted a track 12 having upwardly bent flanges 14. A leaf spring 16 is positioned underneath track 12 and both the track and the leaf spring are secured to the plate 10 by screws 18. Of course, other means of securing the track and the leaf spring to the plate 10 could be used.

The flange 14 is bent at a predetermined acute angle from the plane of the plate 10, such as approximately 45. However, it is to be understood that such angle may vary as will be discussed more fully in the latter part of the description.

The leaf spring 16 also projects upwardly from the plane of the plate 10 by a predetermined angle which is less than the angle of flange 14 for reasons which will also be disclosed latter.

A base 20 upon which may be secured a component 22 is designed so as to snap on track 12 and against plate 10. The base 20.comprises a dovetail slot 24 the width of which is slightly larger than the width of the track 12. The walls 26 of the dovetail slot 24 are sloped the same angle as the flanges l4of the track 12 for a reason which will be disclosed latter. The length of the plate 10, the track 12 and the leaf spring 16 are as long as desired for mounting plural bases 20.

Referring to FIGS. 2 and 3, it will be shown how the base 20 is snapped on track 12 and against plate 10, as well as the nature of the forces and the torques which come into play when the base is in place. FIG. 2 shows the method of inserting the base on the track. A horizontal manual force F is exerted on the base against the action of leaf spring 16 until the edge 28 of the dovetail slot 24 of the base falls over the tip 30 of the track. The base then snaps firmly into place owing to the torques and forces produced by the spring 16. Thus, as illustrated in FIG. 3, the force Fl exerted by the spring can be resolved into two components F2 and F3 acting in the respective directions shown. Force F3 drives the wall 26 of the dovetail slot of the base 20 against the flange 14.0f the track. Force F2 produces a torque F2d2, with corner 32 of the base 20 as the. axis of rotation. This torque causes face of the base to press hard against plate 10. The downward pressure F4 is equal to F2d2/dl.

Therefore, the mechanical forces act in such a way that the base 20 must lie flat against plate 10, and also against flange 14 of the track. The base 20 is therefore always accurately located with respect to plate 1 0 and track 12, possessing only one degree of freedom, which is along the track.

The forces which hold the base can be increased by increasing the strength of the spring, or by varying the dimensions D1 and D2.

The angle of the flange 14 with the base 10 is preferably about 45 in the embodiment disclosed so as to permit the leaf spring 16 to project upwardly by an angle slightly less than 45 under no load condition.

When the base is snapped in position on the plate 10 the leaf spring 16 will be bent upwardly by approximately 45 so that the components F2 and F3 of the force Fl have significant values to ensure that the base is driven hard enough against the flange 14 of the track by the component F3 of the force and against the face 34 of the base by the torque produced by the component F2.

It is also to be understood that various modifications may be made to the above-disclosed track without departing from the scope of the present invention. For example, the track need not to have two side flanges 14 because, in fact, only one side flange 14 opposite the spring is required. In fact, the flange on the spring side acts only as a mechanical back-up protection in case the base is subjected to violent blow on the spring side. In addition, the track does not have to extend the full width of the dovetail slot 24 of base 20. As a matter of fact the track could have a single flange 14 adapted to bear on one sidewall of the dovetail slot 24 of base whereas the spring 16 could be separately secured to the plate so as to contact the other sidewall of the dovetail slot.

The above-disclosed embodiment permits movement along the track while the base is firmly maintained on the plate. However, movement along the track can be prevented by providing slots 38 located along the flanges of the track at appropriate points as illustrated in FIG. 4 of the drawings. Ridges 36 are provided on base 20 to mesh with the slots.

Although the track 12 has been disclosed as being secured to a plate 10, it is to be understood that it may be secured to any supporting surface upon which it is desired to mount electrical or mechanical components.

The base, the track and the plate or supporting surface may be made of electrically conductive material and the arrangement will provide good electrical contact to establish a common electrical ground for the component mounted on the base.

I claim:

l. Snap track means comprising:

a. a supporting plate;

b. a track having a main portion secured to said supporting plate and an integral rigid flange along one of its lateral edges, said flange being inclined upwardly and outwardly from said main portion and making a predetermined angle with respect to the said supporting plate;

0. a leaf spring having one edge fixed with respect to said supporting plate and track and having a portion extending parallel with said track flange on the side of said main portion away from said track flange; said spring portion bending upwardly and outwardly with respect to said track main portion and making an angle, with said supporting plate, less than said track flange predetermined angle;

d. a rigid base to be secured on said supporting plate,

said base having a dovetail slot along one flat surface thereof, said dovetail slot defining apair of reentrant flanges inclined toward one another and making an angle with said one surface of said base substantially equal to said track flange predetermined angle, and wherein said reentrant flanges are separated from one another a distance smaller than the distance between said track flange and said spring portion, whereby in use one of said reentrant flanges is applied against said leaf spring portion while the other reentrant flange stands over said track flange, said base is pushed laterally against the bias of said leaf spring until said other reentrant flange passes completely over said track flange, said base is made to sit squarely on said supporting plate through said flat surface and said other reentrant flange and track flange are snapped in mutual abutting engagement by the bias of said leaf spring acting on said one of said reentrant flanges.

2. Means as claimed in claim 1, wherein said track has a length substantially greater than that of said slot whereby to allow the mounting thereon of more than one base.

3. Means as claimed in claim 1, wherein said track flange predetermined angle is approximately 45.

4. Means as claimed in claim 3, wherein said track has a second rigid flange on the side of said main portion away from said first track flange and between the latter and said spring portion, whereby to serve as a stop for said spring portion and reentrant flange acting thereon in case of excessive transverse movement of said base against said leaf spring portion, the angle of said second rigid flange being 45 in a direction away from said first rigid flange.

5. A snap track as defined in claim 4, wherein slots are provided along the flanges of said track and wherein corresponding ridges are provided inside the dovetail slot in said base for preventing sliding of the base when snapped on the track.

6. A snap track as defined in claim 1, wherein said base, said track and said plate are made of electrically conductive material and in good electrical contact to establish a common electrical ground for said object.

7. Snap track means comprising:

a. a generally flat elongated supporting plate;

b. an elongated track having a main flat portion secured to said flat supporting plate and an integral rigid straight flange along one of its lateral edges, said flange being inclined upwardly and outwardly from said main portion and making an angle of approximately 45 with respect to the said flat supporting plate;

. a leaf spring having an edge fixed with respect to said supporting plate and track and having an elongated spring portion extending from said fixed edge parallel with said track flange on the side of said main portion away from said track flange; said spring portion curving upwardly and outwardly with respect to said track main portion and generally making an angle, with said supporting plate, less than 45;

(1. a rigid base having a flat undersurface, said base to be removably secured on said supporting plate and having a dovetail slot along said flat undersurface, said dovetail slot defining a pair of reentrant flanges having straight inner faces inclined toward one another and making an angle with said flat surface of said base of approximately 45, and wherein said reentrant flanges are separated from one another a distance smaller than the distance between said track flange and said spring portion;

. said track having a second rigid flange on the side of said main portion away from said first track and between the latter and said spring portion, said second rigid flange being inclined upwardly and outwardly from said main portion and making an angle of approximately 45 in a direction away from said first rigid flange, whereby in use on said flat supporting plate through said flat surface and said other reentrant flange and track flange are snapped in mutual abutting engagement by the bias'of said leaf spring acting on said one of said reentrant flanges.

18 i I. i I

Claims

1. Snap track means comprising: a. a supporting plate; b. a track having a main portion secured to said supporting plate and an integral rigid flange along one of its lateral edges, said flange being inclined upwardly and outwardly from said main portion and making a predetermined angle with respect to the said supporting plate; c. a leaf spring having one edge fixed with respect to said supporting plate and track and having a portion extending parallel with said track flange on the side of said main portion away from said track flange; said spring portion bending upwardly and outwardly with respect to said track main portion and making an angle, with said supporting plate, less than said track flange predetermined angle; d. a rigid base to be secured on said supporting plate, said base having a dovetail slot along one flat surface thereof, said dovetail slot defining a pair of reentrant flanges inclined toward one another and making an angle with said one surface of said base substantially equal to said track flange predetermined angle, and wherein said reentrant flanges are separated from one another a distance smaller than the distance between said track flange and said spring portion, whereby in use one of said reentrant flanges is applied against said leaf spring portion while the other reentrant flange stands over said track flange, said base is pushed laterally against the bias of said leaf spring until said other reentrant flange passes completely over said track flange, said base is made to sit squarely on said supporting plate through said flat surface and said other reentrant flange and track flange are snapped in mutual abutting engagement by the bias of said leaf spring acting on said one of said reentrant flanges.

3. Means as claimed in claim 1, wherein said track flange predetermined angle is approximately 45*.

4. Means as claimed in claIm 3, wherein said track has a second rigid flange on the side of said main portion away from said first track flange and between the latter and said spring portion, whereby to serve as a stop for said spring portion and reentrant flange acting thereon in case of excessive transverse movement of said base against said leaf spring portion, the angle of said second rigid flange being 45* in a direction away from said first rigid flange.

7. Snap track means comprising: a. a generally flat elongated supporting plate; b. an elongated track having a main flat portion secured to said flat supporting plate and an integral rigid straight flange along one of its lateral edges, said flange being inclined upwardly and outwardly from said main portion and making an angle of approximately 45* with respect to the said flat supporting plate; c. a leaf spring having an edge fixed with respect to said supporting plate and track and having an elongated spring portion extending from said fixed edge parallel with said track flange on the side of said main portion away from said track flange; said spring portion curving upwardly and outwardly with respect to said track main portion and generally making an angle, with said supporting plate, less than 45*; d. a rigid base having a flat undersurface, said base to be removably secured on said supporting plate and having a dovetail slot along said flat undersurface, said dovetail slot defining a pair of reentrant flanges having straight inner faces inclined toward one another and making an angle with said flat surface of said base of approximately 45*, and wherein said reentrant flanges are separated from one another a distance smaller than the distance between said track flange and said spring portion; e. said track having a second rigid flange on the side of said main portion away from said first track and between the latter and said spring portion, said second rigid flange being inclined upwardly and outwardly from said main portion and making an angle of approximately 45* in a direction away from said first rigid flange, whereby in use one of said reentrant flanges is applied against said leaf spring portion while the other reentrant flange stands over said track flange, said base is pushed laterally against the bias of said leaf spring until said other reentrant flange passes completely over said track flange, said base is made to sit squarely on said flat supporting plate through said flat surface and said other reentrant flange and track flange are snapped in mutual abutting engagement by the bias of said leaf spring acting on said one of said reentrant flanges.