JPS6212963Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a tape measure in which a spiral spring is compressed when the scale is pulled out, and the scale is rewound by its restoring force.

This type of tape measure has a case divided into two parts,
It is screwed in several places around it,
There is one that is screwed to one central shaft that protrudes from one side of the case. The former has the advantage of being able to reduce the diameter of the central shaft, but has the disadvantage of being subject to design constraints because it requires providing several support shafts for screwing around the case. Also, the latter has the advantage of being able to design freely, but the diameter of the central axis becomes larger,
Since the unwinding spring is long, the diameter of the drum is also large, which results in an increase in the size of the entire case.

This idea was devised with the aim of eliminating the above-mentioned drawbacks of the conventional technology.The design was made free by screwing the center shaft, and the unwinding spring was minimized by reducing the diameter of the center shaft. The reason for this is that the drum and case can be made smaller by being shorter.

However, in this device, a drum 3 on which a scale 2 is wound is housed in a case 1, an unwinding spring 4 is housed in the drum 3, and the unwinding spring 4 is compressed when the scale 2 is pulled out. In the tape measure in which the scale 2 that has been pulled out is rewound by its restoring force, a two-part case body 1 forming the case 1 is provided.
A central shaft 5 with a relatively small diameter is provided protrudingly from one side 1a of a and 1b, and a central shaft 5 with a relatively small diameter is provided at an eccentric position (approximately 1/3 of the diameter) from the tip to a depth of approximately 1/2 of the width of the unwinding spring 4. Cut depth 6
is formed to lock the narrow base end 4' of the unwinding spring 4 in the notch 6, and a screw is inserted at an eccentric position of the central shaft 5 so that a part of the circumferential side is continuous with the notch 6. A hole 7 is formed to have approximately the same depth as the notch 6, and a female screw hole 8 of a slightly smaller diameter is connected to the lower end of the hole 7, and a tap screw 10 is inserted through a countersunk hole 9 drilled in the other split case body 1b. The gist of the present invention is a structure of a tape measure characterized by being fastened to the female threaded hole 8. In the illustrated embodiment, the split case body 1
An annular bearing groove 11 is formed in a, and an annular protrusion 12 provided on the lower side of the drum 3 is fitted into the bearing groove 11, so that the drum 3 can rotate smoothly.

Since this device has the above-mentioned configuration, when tightening the case 1, the countersunk hole 9 of the split case body 1b is
The tap screw 10 inserted therethrough passes through the screw insertion hole 7 provided in the central axis 5 of the other split case body 1a, reaches the female threaded hole 8, and its tip end is screwed into the female threaded hole 8. Therefore, since no unreasonable external force is applied to the tip of the center shaft 5, there is no risk of damage due to screwing as in the conventional case.Moreover, the center shaft 5 is reinforced with the tap screw 10 acting as a shaft, and the center shaft 5 is Since the base end of the unwinding spring 4 is wound around the outside of the shaft 5, the notch 6 is also reinforced, so that the diameter of the central shaft 5 can be made as small as possible. Therefore, the length of the unwinding spring 4 can be significantly shortened, which is very economical, and the diameter of the drum can also be reduced, making it possible to downsize the entire case. Furthermore, in this invention, since the case is screwed at one point on the central axis, the assembly work is easy and the design can be made into a desired shape.

[Brief explanation of the drawing]

The drawings show an embodiment of the tape measure according to this invention, in which Fig. 1 is a side view, Fig. 2 is a side view showing the lid open state, and Fig. 3 is an enlarged cross section taken along line A-A in Fig. 1. FIG. 4 is a sectional view of the divided case body. 1...Case, 1a, 1b...Divided case body,
2... Scale, 3... Drum, 4... Rewinding spring, 4'... Narrow base end, 5... Central axis, 6...
Notch, 7...Screw insertion hole, 8...Female screw hole, 9...
...Countersunk hole, 10...Tap screw.

Claims (1)

[Scope of utility model registration request] A drum 3 on which a scale 2 is wound is housed in a case 1, and an unwinding spring 4 is housed inside the drum 3. When pulling out the scale 2, the unwinding spring 4 is compressed, and its restoring force causes the drawer to be pulled out. In this tape measure, a relatively small-diameter center shaft 5 is provided protruding from one of the two halves of the case body 1a, 1b forming the case 1, and its eccentric position (diameter A notch 6 having a depth of approximately 1/2 of the width of the unwinding spring 4 is formed from the tip at the narrow base end 4' of the unwinding spring 4 in the notch 6. A screw insertion hole 7 is formed at an eccentric position of the central shaft 5 to have approximately the same depth as the notch 6, and a part of the circumference is continuous with the notch 6, and a hole with a slightly smaller diameter is provided at the lower end of the screw insertion hole 7. A tape measure characterized in that threaded holes 8 are arranged in series, and a tap screw 10 inserted through a countersunk hole 9 bored in the other split case body 1b is tightened into the female threaded hole 8.