Background of the Invention
When measuring the girth of compressible objects, it is desirable to maintain a uniform tension upon a tape or the like that is extended about the object. For example, when measuring human limbs as part of a weight reduction program, meaningful dimensional comparisons can be made only if measurements are taken with a uniform applied tension on the measuring tape.
Heretofore mechanisms have generally been constructed incorporating coil springs or the like. The springs are deformed depending upon the tension applied to the measuring tape. With the spring compressed a predetermined amount, the tension on the tape can be readily determined.
The main drawback with the prior art apparatus is that they are relatively complicated in construction and generally require the assembly of numerous interacting elements. Also, ease of handling has not particularly aided accurate readings to be obtained.
The present invention is specifically directed to overcoming these prior problems.
Summary of the Invention
The present invention is an instrument for measuring the girth of compressible objects and comprises a flexible tape for extension about an article to be measured, and a tension reading member. The tension reading member comprises first and second sections and a flexible, bendable hinge portion interconnecting the same and permitting relative movement between the sections.
The first section is secured with the end of the tape. The first section is controlled by grasping and drawing the tape with one hand. The second section is drawn by applying a force with the other hand oppositely that on the tape, deforming the hinge portion and shifting the second section relative to the first section. The relative positions of the first and second sections indicates the degree of tension applied to the tape.
It is the principal object of the present invention to provide a simplified mechanism for uniformly tensioning a measuring tape.
In a preferred form of the invention the tension reading member is fabricated as a single-piece in a substantially flat configuration and from a resilient material. The portion interconnecting the first and second sections has a reduced cross-sectional area which permits relative flexure of the first and second sections substantially in the plane of the member. The member can thus be simply molded as from plastic or the like and, because of its minimal thickness, is an unobtrusive apparatus.
To take readings from the tension reading member, a pair of elongate edges are defined on each of the first and second sections and arranged substantially parallel and adjacent to each other. At least one readily visible indicating mark is included adjacent each edge, which marks align at a predetermined tension. Measurements under consistent tension can be made rapidly by consistently aligning the indicating marks through successive measurements.
In a preferred form of the invention an opening is defined in the tension reading member through which the tape is extensible. The opening is preferably U-shaped, with a straight edge defined transverse to the length of the tape, upon which edge the tape is guided as it is drawn taut about an object.
One of either the first or second sections has a cutout, with the other of either the first or second sections having an arm which is extensible within the cutout. In a preferred form, a pair of stops protrude into the opening and engage an expanded portion of the arm to prevent overextension as might damage the flexible hinge portion interconnecting the first and second sections.
To facilitate grasping of the tension reading member, the second portion is formed with two diverging edges defining an expanded portion which can be conveniently maintained between the thumb and finger of the user. This assures that a positive grip is maintained as the second section is manipulated. Also the arrangement of parts is such that drawing the tape taut exerts only even pull on the tension reading member avoiding off-center forces which might make handling more difficult.
Brief Description of the Drawings
FIG. 1 is a sectional perspective view of a measuring instrument constructed in accordance with the present invention with the measuring tape drawn to a predetermined tension and illustrative manipulation shown fragmentally;
FIG. 2 is a top sectional view of the measuring instrument in FIG. 1;
FIG. 3 is an elevated sectional view of the measuring instrument with the measuring tape in a relaxed state;
FIG. 4 is an elevated side view of the measuring instrument.
Detailed Description of the Drawings
A preferred form of the invention is illustrated in FIGS. 1-4 and comprises generally a flexible measuring tape 10, with graduations along its length, and a substantially planar tension reading member, indicated generally at 12. The tape itself is generally of material not subject to appreciable nor significant elongation under the force magnitudes employed.
The tension reading member 12 comprises a first and second sections, 14 and 16 respectively, interconnected by a flexible bendable hinge portion 18 having a reduced cross-sectional area, transverse to the length of the tape, that permits relative flexing of the first and second sections 14, 16 in the plane of the member 12. The flexible hinge portion is only bendable within the elastic limits of the material of which the member 12 is molded or made. Flexibility as related to the hinge portion is meant to describe the fact that bending of the material is concentrated in the hinge 18 area with the ability of the material to spring back to its original position upon release of tension on the tape 10. In a preferred form, the member 12 is fabricated as a single piece from a material that is rigid enough to maintain the first and second sections in relatively fixed relationship, yet which is deformable at the hinge 18 under a predetermined force, with the hinge dimensions and material chosen accordingly.
A U-shaped opening 20 is provided in the member and defines a straight edge 22 transverse to the length of the tape 10. The end of the tape is extended around the first section 14 and over the edge 22 and doubled back and secured as by rivets 21. The tape 10 slides over the edge 24 as it is drawn through the opening and tightened about an article. The width of the opening 20 is chosen to minimize binding of the tape with the opposing edges of the opening 20 when drawn through as in FIGS. 1 and 2. The curved bottom edge 24 of the opening serves to guide the tensioned tape toward the edge 22 so that the tape is consistently positioned when the measurements are taken. An inverted triangular mark 26 is situated immediately above the top of the edge 22 and aligns with the graduations on the tape to clearly indicate the desired measurement.
The first section 12 has an arm 28 extending substantially parallel to the length of the tape 10. A U-shaped cutout 30 in the second section 16 opens toward the first section 14 and receives the arm 28. The upper edge 32 of the arm 28 is substantially parallel to the edge 34 of the second section 16 defining the cutout 30.
To take a measurement, the tape is extended about an article (not shown) and outwardly through the opening 20. The second section is grasped between the thumb and index finger on one hand, as illustrated in FIG. 1, and the tape drawn taut by the other hand. To accommodate the one hand on the member 12, the upper and lower edges 36,38 of the second section 16 diverge towards one side defining an expanded head 40 which prevents the hand from slipping when the tape is tightened. The tape is tensioned by exerting opposing forces on the tape and the second section, thereby deforming the hinge portion 18 and shifting the arm 28 from the relaxed position in FIG. 3 towards the left, relative to the cutout, as in FIG. 1. It may be observed that the tape connection through the rivets 21 places the pull on the tape centrally aligned with the resistant force of a person's thumb and finger retention applied to the section 16. No skewing force is applied to impede accurate readings in any position about any limb of a patient.
A pair of indicating marks 42, 44 extend respectively from the first and second sections and into the space 46 therebetween. Consistant tension can be applied to the tape by aligning the marks 42,44 as successive measurements are taken. Additional marks can be provided on either of the first and/or second sections if different tensions are desired. With the marks 42,44 aligned, the measurement is clearly indicated by the lower mark 26 above the tape 10.
To prevent overstressing of the hinge 18, a stopping arrangement 48 is constructed by a cooperative arrangement of the first and second sections. The arm 28 is expanded at its end as to form a T-shape. Extending from opposite edges of, and into the cutout are a pair of stops 49 integrally constructed with the second section. The stops abut the expanded end 50 of the arm preferably before the hinge is stressed beyond its elastic limit.
The horizontal edges 52, 54 of the arm end 50 and stop, respectively, maintain the arm substantially centered and guide the arm within the cutout. The edge 56 of the cutout serves as a stop for the vertical edge 58 at the end of the arm. The arrangement of the stop 49, the expanded arm end 50 and the edge defining the cutout, prevents overextension of the hinge 18 in all directions in the plane of the tension reading member 12.
The foregoing description was made for purposes of clarifying the operation of the invention, with no limitations to be derived therefrom. The scope of the invention is to be ascertained from the appended claims.