US3780974A - Device for the fixing,being combined with slow lowering,of the sliding pole of a portable motion picture screen stand - Google Patents

Abstract

A device for the locking and slow lowering of the sliding pole of a portable motion picture screen stand, which is characterized by mounting a sliding pole into a hollow supporting pole so that the former can go up and down along the inside of the latter supporting piece is fixed to a hole which is provided at the upper part or at an appropriate part of the hollow supporting pole and a lever is hinged to said supporting piece by an axis. In addition, the lower end of said lever projects from the outside of the hollow supporting pole by the force of a spring and the inside of the lever comes in contact with the outside of the sliding pole with the upper and lower points of contact which are provided at about even distance from the axis and which have a dent therebetween.

Description

United States Patent Takahashi 1 DEVICE FOR THE FIXING, BEING COMBINED WITII SLOW LOWERING, OF THE SLIDING POLE OF A PORTABLE MOTION PICTURE SCREEN STAND [76] Inventor: Sasuke Takahashi, 34/ l 1,

Yasunakacho-6-chome, Yao City, Prefecture of Osaka, Japan 22 Filed: Dec. 27, 1971 21 Appl. No.: 212,001

30 Foreign Application Priority Data 2,628,854 2/1953 Gardner 248/411 Dec. 25, 1973 Dumais 248/171 Primary Examiner-Marion Parsons, Jr. Attorney-E. F. Wenderoth et al.

[57] ABSTRACT A device for the locking and slow lowering of the sliding pole of a portable motion picture screen stand, which is characterized by mounting a sliding pole into a hollow supporting pole so that the former can go up and down along the inside of the latter supporting piece is fixed to a hole which is provided at the upper part or at an appropriate part of the hollow supporting pole and a lever is hinged to said supporting piece by an axis. In addition, the lower end of said lever projects from the outside of the hollow supporting pole by the force of a spring and the inside of the lever comes in contact with the outside of the sliding pole with the upper and lower points of contact which are provided at about even distance from the axis and which have a dent therebetween.

3 Claims, 3 Drawing Figures PATENTEDnm 09m 3.780.974

INVENTOR.

Sasuke Takahashi @ZMAAS WIS DEVICE FOR THE FIXING, BEING COMBINED WITH SLOW LOWERING, OF THE SLIDING POLE OF A PORTABLE MOTION PICTURE SCREEN STAND The present invention relates to a device for the locking and slow lowering of the sliding pole of a portable motion picture screen. According to the invention, a sliding pole is mounted into a hollow supporting pole so that the former can go up and down along the inside of the latter. A supporting piece is fixed to a hole which is provided at the upper part or at an appropriate part of the hollow supporting pole and a lever is hinged onto said supporting piece by an axis. In addition, the lower end of said lever projects from the outside of the hollow supporting pole by the force of a spring and the inside of the lever comes in contact with the outside of the sliding pole with theupper and lower points of contact which are provided at about even distances from the axis and which have a dent therebetween.

Conventional locking devices for a portable motion picture screen stand are apt to cause the sudden drop of the sliding pole, which may damage the screen stand and the screen surface.

According to the device of the present invention, the principle of a lever is applied in the following way. When the sliding pole is released from a fixed raised position/another holding force is given to it immediately after such release, and when the sliding pole is released again from the second force a still further holding force is applied immediately after such release. Thus, the locking and the releasing of the sliding pole are repeated alternately by a very light operation of a lever and at the same time the sliding pole moves downwardly under its dead load at very short intervals.

The invention will now be described with particular reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a portable motion picture screen stand made in accordance with the present invention;

FIG. 2 is a magnified vertical section showing the essential parts of the present device; and

FIG. 3 is a horizontally cross-cut plane view of said essential part.

A sliding pole 2 is mounted in a hollow supporting pole 1 so that the former can move up and down along the inside of the latter. A supporting piece 4 is fixed to a hole 3 provided on one side of the upper part of said hollow supporting pole l. A lever 6 is hinged onto said supporting piece 4 by an axis 5. The lower end 8 of said lever 6 is made to project from the outside of the hollow supporting pole 1 by the force of a spring 7. The inside of the lever 6 is made to contact one side of the sliding pole 2 with the upper and lower points of tances from the axis 5. Case 9 has a built-in spring for the automatic winding of screen 10 and'hook 11 holds the screen in its opened position.

When the point of contact A or A on the inside of the upper part of the lever 6 contacts the sliding pole 2, the latter is forced against the hollow supporting pole l and is locked at that position. lf the point of contact A or A is removed from the sliding pole 2 by pushing the lower end 8 of the lever 6 the sliding pole 2 moves down rapidly. However, it is possible to make the sliding pole 2 move slowly under its dead load by repeatedly pushing the lower end 8 of the lever 6 intermittently.

Thus, the device of the present invention has the advantages that its operation is simple and that it can wind up the screen into the case safely while automatically preventing the screen surface from being damaged by friction. It is of course possible to change the design of the present device so far as such change does not deviate from the spirit of the present invention.

What I claim is:

l. A device for locking and slowly lowering the sliding pole of a portable motion picture screen comprising a sliding pole telescopically mounted in a hollow supporting pole so that said sliding pole is adapted to move up and down along the inside of said hollow supporting pole, said hollow pole having a hole in a side wall thereof and a supporting means securely mounted on said hollow supporting pole adjacent said hole, a lever pivotally mounted on said means by an axle, said lever having a lower and an upper end, said upper end having first and second spaced apart contact points thereon, said points being positioned on the side of said lever and facing said hole and said sliding pole exposed therein, said first point being positioned above said axle and said second point being positioned below said axle, spring means forcing said lower end of said lever outwardly away from said hollow supporting pole and simultaneously forcing said first contact point to press against said sliding pole through said hole for holding said sliding pole against downward movement, said second contact point being adapted to contact said sliding pole through said hole for holding said sliding pole against downward movement when said lower end of said lever is firmly pressed.

2. The device of claim 1 wherein said hole and said supporting means are located near the upper end of said supporting pole.

3. The device of claim 1 wherein said first and second contact points are equidistant from said axle and wherein a dent is located between said first and second contact points.

Claims (3)

1. A device for locking and slowly lowering the sliding pole of a portable motion picture screen comprising a sliding pole telescopically mounted in a hollow supporting pole so that said sliding pole is adapted to move up and down along the inside of said hollow supporting pole, said hollow pole having a hole in a side wall thereof and a supporting means securely mounted on said hollow supporting pole adjacent said hole, a lever pivotally mounted on said means by an axle, said lever having a lower and an upper end, said upper end having first and second spaced apart contact points thereon, said points being positioned on the side of said lever and facing said hole and said sliding pole exposed therein, said first point being positioned above said axle and said second point being positioned below said axle, spring means forcing said lower end of said lever outwardly away from said hollow supporting pole and simultaneously forcing said first contact point to press against said sliding pole through said hole for holding said sliding pole against downward movement, said second contact point being adapted to contact said sliding pole through said hole for holding said sliding pole against downward movement when said lower end of said lever is firmly pressed.

2. The device of claim 1 wherein said hole and said supporting means are located near the upper end of said supporting pole.

3. The device of claim 1 wherein said first and second contact points are equidistant from said axle and wherein a dent is located between said first and second contact points.

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