CN1020981C - Improvements in magnetic tape cassettes - Google Patents

Abstract

An improved loose limiter of cassette is provided. A pre-tension is added on the polypropylene loose limiter of the invention, due to using the polypropylene, a separated bearing material is not requested to be casing pressed on the loose limiter.

Description

Improvements in magnetic tape cassettes

The application is that the sequence number of on March 25th, 1987 application is the 030698(United States Patent (USP)) part of application case continues.

The invention relates to the general tape cassete of a kind of videocassette recorder, particularly about the loose limiter of tape cassete.

Generally comprising a loose limiter in the tape cassete, in VHS tape cassete and " β " tape cassete, is respectively swiping sheet shape and detent shape limiter, and loose limiter is to tape preloading, so that tape is unlikely unexpected loose.Loose limiter must add enough tension force in advance to tape, but does not also allow to produce excessive friction simultaneously, otherwise can cause overload and excessive wearing and tearing.Limiter was made with metal or polyester material in the past, but they must overlap and press polytetrafluoroethylene floor, to obtain desired friction characteristics.This method has two shortcomings, and at first, teflon is very expensive, and has increased extra manufacturing process.In addition, be used for to loose the cementing agent that teflon is fixed on the swiping sheet inevitably to spill polluting tape.What Sai Tuo (Saito) disclosed in the US4290567 patent is exactly an example of this configuration.A loose limiter of Sai Tuo invention has one to take back curved free end, makes with the elastoplast band, and it contains charcoal, and graphite or other can produce the material of low frictional factor at free end.Like this, Sai Tuo has just saved the teflon supporting material in this embodiment.

The invention relates to a kind of improvement of tape cassete, the loose limiter in the particularly this tape cassete.

The purpose of this invention is to provide a kind of swiping sheet of making by the monolithic elastic plastic material or the loose limiter of detent formula.

Loose limiter with polypropylene is made can obtain desired friction characteristics and mechanical property.Use this material not additional support band or high-abrasive material.Therefore just avoid expending the additional materials that there is accessory problem in those.

Brief Description Of Drawings:

Fig. 1 is the backplan of expression upper cartridge body interior shape.

Fig. 2 is the partial top view of expression lower box body interior shape.

Fig. 3 is the axis side view of expression lower box body.

Fig. 4 is the planimetric map that is illustrated in a plurality of loose limiters that form on the continuous plastic sheet.

Fig. 5 is the axis side view of the rolled-up loose limiter of finishing of expression.

Fig. 6 is the plan view of the independent loose limiter that scales off of the continuous sheet from Fig. 4 and Fig. 5.

Fig. 7 is the lateral elevational view that amplify at the loose limiter top of Fig. 6.

Fig. 8 is the planimetric map with another embodiment of the similar loose limiter of Fig. 4.

Fig. 9 is the single loose limiter that separates from sheet material shown in Figure 8.

Figure 10 be the expression loose another embodiment of limiter with Fig. 4 and 8 similar views.

Figure 11 is the plan view of the single loose limiter that downcuts from sheet material shown in Figure 10.

The total outside drawing of tape cassete is illustrated on Fig. 1-3, and tape cassete comprises upper cartridge body 10 and lower box body 12, and upper cartridge body comprises pair of windows 14 and a reel spring 16, and projection 18 is passed out the inside surface that hole on spring is fixed on spring upper cartridge body.This spring has one section archwise structure, as shown in the figure, the back shaft 20 of its end contact reel of tape 22, reel of tape is contained on the lower box body 12 rotationally.Perforate 24 is used for holding unshowned video recorder tape reel driving shaft on lower box body.Tape 26 and extends on another reel from a reel by the access portal in tape guide 28 and the tape cassete on reel 22.

Present narration loose limiter of the present invention it is to be noted that swiping sheet that " loose limiter " speech both had been used for describing the VHS tape cassete herein also is used for describing the tape detent of " β " tape cassete.Fig. 1 and Fig. 2 show the swiping sheet 50 that adopt a VHS tape cassete and it, one end of swiping sheet 50 is clipped on the bracket 52 that forms on the upper cartridge body 12, a groove is arranged on the bracket, one end of swiping sheet just is inserted in the inside, and pile 54 further tightens up swiping sheet 50, the other end roof pressure tape 26 of swiping sheet, force tape to contact with pin 56, tape is clamped in swiping sheet 50 and sells between 56, and tape is formed necessary friction, to keep tape not loose by accident.

The detail drawing of swiping sheet 50 is shown in Fig. 8 and 9, and each swiping sheet is rectangle basically, comprises a center pit 58 and an otch 60, forms a leg 62, and the groove of leg and bracket 52 matches.Fig. 8 represents a plurality of swiping sheets made from continuous plastic sheet coiled material or sheet material.These swiping sheets form along one side of sheet material, and connect together with continuous plastics brace 64, along defiber 66 single swiping sheet are sheared then.

A kind of replacement form 68 of Figure 10 and 11 expression swiping sheets, the swiping sheet of this form has the hinged joint window 72 of a hole 70 and three openings, and this window can wrap on the pile 54 shown in the image pattern 2, keeps the location further to make swiping sheet 68.The swiping sheet of this form also has advantage, promptly can reduce the offal that produces in process of production.

Fig. 3 has represented the lower box body 74 of " β " tape cassete, casting has a pair of loose limiter bearing 76 on the lower box body 74, the loose limiter that is used in " β " tape cassete is a tape detent 78, two detents are arranged in each tape cassete usually, one end of detent is contained on the bearing 76, the other end has a bending part 80, as Fig. 3 and Fig. 7 finding.Broken line 82 contact tapes, there is a slight fillet at the broken line place, to reduce the wearing and tearing of tape.Fig. 4 and Fig. 5 are illustrated in a plurality of " β " tape detent 78 that forms on the continuous plastic sheet, and C type otch 84 separately forms swiping sheet 86 to the tape detent, and C type otch can be fixed on detent on the box body.Single detent is sheared on 88 along separator bar 90 from plastic plate.

Can find polypropylene applicable to various types of loose limiters, this material has enough rigidity, tape imposed Necessary Tensility or to preload.Need not additional teflon or other area supporteds simultaneously and just can possess desired friction parameter.Polypropylene has enough " memory ", suitable spring rate to be provided and can at high temperature to remain unchanged.From the angle of chemistry, it can not damage tape.The loose limiter of polypropylene scales off from the coiled material blank, can directly be assembled in the tape cassete, and this has just saved one manufacturing process of additional one second area supported.Because do not need cementing agent, this also causes the rotten possibility of tape with regard to having been avoided owing to the diffusing leakage of cementing agent.

In view of disclosing and described the preferred embodiments of the present invention, that makes therefrom changes the scope that shape does not exceed claim of the present invention.

Claims (2)

1, a kind of loose limiter, be applicable in the tape cassete of box body pattern with a pair of rotatable reel of dressing, wherein, tape is on reel, and between two dishes, extend, box body comprises that a loose limiter bracket and guiding tape pass the guidepost of box body internal channel opening, this loose limiter is made of the piece plastic diaphragm, this loose limiter has the overall shape of rectangle, and this loose limiter is fixed in this bracket along its first edge, and its second edge stretches out the formation cantilever from this bracket, thereby surface restraint tape along this second edge, the diaphragm of this loose limiter and shape make it possible to provide enough " memory " thereby give loose limiter suitable spring rate, it is characterized in that

Described loose limiter is made by polypropylene.

2, loose limiter as claimed in claim 1 is characterized in that this loose limiter is self inflection, thereby forms a broken line, and this limiter contacts tape along this broken line.

Images