JPH04231138A - Rivet-fixing tool - Google Patents

Abstract

PURPOSE: To prevent the actuation of a rivet tool on an overpressure having a possibility of receiving damage by selecting an operating air pressure so as to close the inlet side of a poppet valve when this pressure exceeds the max. pressure. CONSTITUTION: The intensity of a spring means 28 shifts a rod assembly by depression of a trigger 12 and moves a push rod 18 existing in an advance position from an upper position to a lower position, insofar as the operating air pressure is below the max. pressure. The inlet side of the poppet valve 30 is thereby opened. When the operating air pressure exceeds the max. pressure, the pressure is so selected as to overcome the spring and to close the inlet side of the poppet valve by shifting the push rod from the advance position to a retraction position. As a result, the inlet side of the valve stays sealed and the outlet side keeps a tool chamber connected to a discharge conduit and consequently, the tool may be prevented from being actuated by the overpressure having the possibility that the tool is damaged.

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION This invention relates to rivet setting tools that rely on air pressure as the motive force.

0002

BACKGROUND OF THE INVENTION Riveting tool operators generally understand that the speed of a rivet tool is a function of the supplied air pressure, and therefore operators tend to increase air pressure to increase work efficiency. be. However, such tools are designed to operate within a selected pressure range, and operating beyond this range will result in rapid wear of the mechanism.

It is therefore an object of the invention to prevent the rivet tool from operating beyond the permissible pressure range. Other objects and advantages of the invention will become apparent from the following description of the specification and the accompanying drawings, which illustrate a presently preferred embodiment employing the principles of the invention in accordance with the instructions of the patent laws.

0004

DESCRIPTION OF THE PREFERRED EMBODIMENTS A rivet setting tool 10 includes a shaped trigger 12 that is rotatable about a trigger point 13 and has a camming surface 14 along its bottom surface. This cam surface is engageable with a displaceable molded cam follower in the form of a cylindrical rod holder 16. Push rod 18 that can be displaced up and down within the vertical bore 17 of the rod holder 16
is retained by a retaining pin 19 placed in a suitable slot 20 provided therein. An inner and outer spring 28 is installed in a compressed state between the pushrod head 24 and the rod holder bottom shoulder 26. The ends of the slot 20 define fully retracted and fully extended positions of the pushrod relative to the rod holder 16.

[0005] Below this pressure regulator assembly,
A conical face dual acting poppet valve 30 is provided which is supported within a suitable bore 32. This bore 32 communicates with a bore 34 in which a pressure regulator assembly is installed. In normal operation, trigger 1
2 is released (position shown), pressurized inlet air from an external source entering poppet valve bore 32 below the poppet valve through opening 36 forces lower valve seal 38 to the closed position, causing pressure regulator Raise the assembly and return the trigger to its de-energized position. Air from the tool room will then flow to the exhaust port 44 through the conduit 40 and the open exhaust side of the poppet valve. During normal operation, when the trigger is pulled, the pressure regulator assembly is lowered, sealing the upper valve seal 46 against the valve body 48 and opening the inlet side to allow supply air to flow through conduit 40 and into the tool chamber.

The strength of the spring 28 is such that when the trigger is depressed to energize the system, if the inlet air pressure exceeds a certain specified pressure, the spring will compress and force the rod against the stationary push rod 18. - It is selected so that the holder 16 can be displaced downward. The inlet side of the valve will therefore remain sealed and the outlet side will continue to connect the tool chamber with the exhaust conduit, thus preventing the tool from operating with excessive pressure that could result in damage.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a portion of a rivet tool constructed in accordance with the teachings of the present invention.

2 is a view similar to FIG. 1, but showing the valve in an open position; FIG.

[Explanation of symbols]

10 Rivet fixing tool 12 Trigger 13 Trigger point 14 Cam surface 16 Rod holder 17 Vertical bore 18 Push rod 19 Holding pin 20 slots 24 Head part 26 Bottom shoulder 28 Spring 30 Poppet valve 32 Boa 34 Boa 36 Opening 38 Lower valve seal 40 Conduit 44 Exhaust port 46 Upper valve seal 48 Valve body

Claims (1)

[Claims] 1. A two-way poppet valve that alternately connects an air line from a tool room to an inlet line and an exhaust line, the poppet valve including a body and a spool assembly having upper and lower valve seals, and a release position. a trigger displaceable between a depressed position and a cam surface; and a retractable rod assembly disposed between the trigger and the spool assembly and displaceable between an up and down position. a rod assembly including a pushrod having a head and rod holder means supporting the pushrod and selectively movable between an advanced position and a retracted position relative to the pushrod; spring means disposed in compression between the head of the pushrod and the rod holder means to maintain the pushrod in the advanced position and resist displacement of the pushrod to the retracted position; and the strength of the spring means is such that, as long as the operating air pressure is less than a maximum pressure, depression of the trigger displaces the rod assembly to move the push rod from the forward position to the upper position. to the lower position,
Thereby, the inlet side of the poppet valve is opened, but when the operating air pressure exceeds the maximum pressure, pressure overcomes the spring and displaces the push rod from the advanced position to the retracted position, causing the poppet valve to A rivet fixing tool, characterized in that the rivet fixing tool is selected to close the entrance side of the rivet.