CN203408028U

CN203408028U - Anti-cheating visual chart

Info

Publication number: CN203408028U
Application number: CN201320304483.5U
Authority: CN
Inventors: 吴善锁
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-05-13
Filing date: 2013-05-13
Publication date: 2014-01-29
Anticipated expiration: 2023-05-13

Abstract

The utility model discloses an anti-cheating visual chart. The anti-cheating visual chart comprises a base frame, E blocks, rotary shafts, gears and synchronous belts, and is characterized in that the gears are driven by ratchet mechanisms; each rotary shaft is connected to the back surface of a central point of the corresponding E block; each gear is sleeved onto the corresponding rotary shaft; the gears which are sleeved onto the rotary shafts of the E blocks in the same row are connected by the corresponding synchronous belt into a whole body; each ratchet mechanism comprises a ratchet wheel with eight equally-spaced wheel teeth, a rotary spring, a stirring rod and a positioning sheet which is fixed on the base frame. According to the anti-cheating visual chart, the opening direction of each E block can be accurately and conveniently regulated, the phenomenon that a testee obtains a false visual value through memorization is prevented, and a test result is more scientific and more accurate.

Description

Anti-cheating visual acuity chart

Technical field

This utility model relates to a kind of instrument that vision is used of measuring, and is a kind of anti-cheating visual acuity chart specifically.

Background technology

Tradition visual acuity chart is the fixing leaflet of version, often measure and watch and can make measured remember to test the direction of block, even, in order to reach certain vision, measured can adopt the mode of reciting visual acuity chart to obtain false vision value, causes the mistaken diagnosis of the side of test, erroneous judgement.Chinese utility model ZL 201120564106.6 discloses a kind of anti-memory visual acuity chart for this reason, comprise pedestal and discoid test block, test center, the block back side is provided with cylindrical plunger, pedestal is provided with through hole, although can prevent that by rotary test block measured is by memory cheating, but the defect of this patent also clearly: 1, melancholy sight line can be done in the disk sideline of discoid test block, and impact test effect, particularly to the test of the less test block of several row below; 2, operation inconvenience, the direction of each test block changes to be needed to go to turn with hands, is not only time-consumingly also difficult to very align direction.

Summary of the invention

The purpose of this utility model is to provide a kind of anti-cheating visual acuity chart, and this visual acuity chart is easy and simple to handle, can science, reflect exactly the vision of the measured.

The technical solution adopted in the utility model is: a kind of anti-cheating visual acuity chart, comprise base frame, E block, rotating shaft, gear and Timing Belt, and it is characterized in that described gear is driven by ratchet mechanism.

The described E block central point back side is connecting rotating shaft, and in rotating shaft, cover has gear, and the gear set specifications model of overlapping in described same row E block rotating shaft is identical, and is connected by Timing Belt, and described ratchet mechanism is located in the E block rotating shaft on the most close base frame right side.

Described ratchet mechanism comprises with the ratchet of eight equidistant gear teeth, the spring that circles round, stirs bar and be fixed on the spacer on base frame.

This utility model can accurately regulate the opening direction of E block easily, prevents that measured from obtaining false vision value by memory, makes test result more scientific, accurate.

Fig. 1 is vivid schematic diagram of the present utility model.

Fig. 2 is this utility model internal structure schematic diagram.

The specific embodiment

Below in conjunction with drawings and Examples, this utility model is described in further detail.

Referring to Fig. 1 and Fig. 2, a kind of anti-cheating visual acuity chart, comprises base frame 1, E block 2, rotating shaft 3, gear 4, Timing Belt 5.The gear set specifications model of overlapping in described same row E block rotating shaft is identical, and the E block rotating shaft on described the most close base frame right side is provided with ratchet mechanism.Described ratchet mechanism comprises ratchet 6 with eight equidistant gear teeth, convolution spring 8, stirs bar 7 and be fixed on the spacer 9 on base frame.

During use, stir bar 7, drive ratchet 6, gear 4 and E block 2 to rotate together, often pull out and stir bar, whole row E block just rotates 45 degree, and this utility model is easy and simple to handle, can prevent that measured from obtaining false vision value by memory.

Originally illustrate is not to restriction of the present utility model; this utility model is not limited to above-mentioned giving an example, and those skilled in the art, in essential scope of the present utility model; the variation of making, remodeling, interpolation or replacement, all should belong to protection domain of the present utility model.

Claims

1. an anti-cheating visual acuity chart, comprise base frame, E block, rotating shaft, gear and Timing Belt, it is characterized in that described gear is driven by ratchet mechanism, the described E block central point back side is connecting rotating shaft, in rotating shaft, cover has gear, the gear set specifications model of overlapping in the rotating shaft of same row E block is identical, and is connected by Timing Belt, and described ratchet mechanism is located in the E block rotating shaft on the most close base frame right side.

2. according to a kind of anti-cheating visual acuity chart claimed in claim 1, it is characterized in that: described ratchet mechanism comprises with the ratchet of eight equidistant gear teeth, the spring that circles round, stirs bar and be fixed on the spacer on base frame.