JPH01101783U

JPH01101783U -

Info

Publication number: JPH01101783U
Application number: JP19845187U
Authority: JP
Priority date: 1987-12-25
Filing date: 1987-12-25
Publication date: 1989-07-10

Description

[Brief explanation of the drawing]

第１図〜第６図は本考案の一実施例を示すもの
で、第１図はピストンが進動を開始するときの状
態を示す油圧ブレーカの縦断面図、第２図はピス
トンが進動端へ移動した状態を示す油圧ブレーカ
の縦断面図、第３図はピストンが退動を開始する
ときの状態を示す油圧ブレーカの縦断面図、第４
図はピストンが退動端へ移動した状態を示す油圧
ブレーカの縦断面図、第５図は切換弁の拡大縦断
面図、第６図イ，ロ，ハはそれぞれ操作弁の切換
動作を説明する第１図のＸ―Ｘ線拡大断面図、第
７図は従来のピストンストローク切換機構の要部
断面図である。１……シリンダ、３……ピストン、６……下受
圧面、８……高圧室、１０……主パイロツト室、
１１，１２……副パイロツト室、１８，１９，２
０……切換流路、２１……切換弁、２９……変圧
室、４０……操作弁、Ｂ……油圧ブレーカ。 Figures 1 to 6 show an embodiment of the present invention. Figure 1 is a longitudinal sectional view of the hydraulic breaker showing the state when the piston starts moving, and Figure 2 shows the state when the piston starts moving. FIG. 3 is a vertical cross-sectional view of the hydraulic breaker showing the state when the piston starts to retreat; FIG.
The figure is a vertical cross-sectional view of the hydraulic breaker showing the state in which the piston has moved to the retraction end, Figure 5 is an enlarged vertical cross-sectional view of the switching valve, and Figures 6 A, B, and C each explain the switching operation of the operating valve. FIG. 1 is an enlarged cross-sectional view taken along the line X--X, and FIG. 7 is a cross-sectional view of essential parts of a conventional piston stroke switching mechanism. 1... Cylinder, 3... Piston, 6... Lower pressure receiving surface, 8... High pressure chamber, 10... Main pilot chamber,
11, 12... Sub-pilot room, 18, 19, 2
0...Switching flow path, 21...Switching valve, 29...Transforming chamber, 40...Operation valve, B...Hydraulic breaker.

Claims

[Scope of utility model registration request]

The cylinder equipped with the switching valve has a high pressure chamber into which high pressure oil is fed to pressurize the pressure receiving surface of the piston to move the piston backward from the moving end, and the switching valve to move the plunger of the switching valve backward from the moving end. a main pilot chamber communicating with a variable pressure chamber formed in the valve body of the valve;
At least one sub-pilot chamber is formed between the high-pressure chamber and the main pilot chamber, and a switching flow path communicating between the main pilot chamber and the sub-pilot chamber is opened or shut off. A piston stroke switching device in a hydraulic breaker equipped with an operating valve that is operated to change the moving end of a pressure receiving surface.