Overspeed safety device for rotary tools

Claim 2

In a rotary tool including a housing, a rotary air motor, an inlet port for admitting operating air to the motor, and a safety valve controlling air flow through the port to the motor, a trip releasably supporting the valve in an open normal position, the valve being constantly biased against the trip in a closing direction, the trip being located at a predetermined radial distance from the axis of the motor, trip actuating means carried by the motor having response to a predetermined centrifugal force developed by the motor to move outwardly in a path of rotation in which the trip is located so as to cause the latter to be upset and as a consequence release its support from the valve, and the housing having first and second internal shoulders; wherein the safety valve is a leaf spring anchored at one end upon the first shoulder and having an opposite end resiliently movable from a position lying closed over the port to the open normal position; and wherein the trip is a pin having a bottom end releasably seated upon the second shoulder and having an upper end normally abutting an undersurface of the leaf spring between the ends of the latter and supporting the leaf spring in its open position.

Claim 3

In a rotary tool including a rotary air motor, an inlet port for admitting operating air to the motor, a first valve located to one side of the port normallY controlling air flow through the port to the motor, a centrifugal governor carried by the motor regulating operation of the valve in response to development of a predetermined speed level of the motor, a resilient air shut-off safety valve located to the opposite side of the port having a first position in which it is closed over the port, a releasable trip normally stressing the safety valve from its closed position to a reverse open normal position, and trip actuating means carried by the motor having response to a predetermined centrifugal force developed by a higher level of speed of the motor to upset the trip and as a consequence release its stressing effect from the safety valve, including a housing having an internal shoulder, wherein the safety valve is a leaf spring anchored at one end to the shoulder and having an opposite free end which in the first position of the safety valve lies closed over the port, and including a second internal shoulder of the housing, wherein the trip is a pin having a bottom end releasably seated upon the latter shoulder and having an upper end abutting an undersurface of the safety valve between the ends of the latter.

Claim 4

In a rotary tool including a rotary air motor, an inlet port for admitting operating air to the motor, a first valve located to one side of the port normallY controlling air flow through the port to the motor, a centrifugal governor carried by the motor regulating operation of the valve in response to development of a predetermined speed level of the motor, a resilient air shut-off safety valve located to the opposite side of the port having a first position in which it is closed over the port, a releasable trip normally stressing the safety valve from its closed position to a reverse open normal position, and trip actuating means carried by the motor having response to a predetermined centrifugal force developed by a higher level of speed of the motor to upset the trip and as a consequence release its stressing effect from the safety valve, including a housing having an internal shoulder, wherein the safety valve is a leaf spring anchored at one end to the shoulder and having an opposite free end which in the first position of the safety valve lies closed over the port, and including a second internal shoulder of the housing, wherein the trip is a pin having a bottom end releasably seated upon the latter shoulder and having an upper end abutting an undersurface of the safety valve between the ends of the latter.

Claim 5

In a rotary tool as in claim 2, wherein the second shoulder has a shallow depression, the pin has a rounded detent bottom end releasably seated in the depression and has a rounded top end abutting the undersurface of the safety valve.

Claim 6

In a rotary tool as in claim 3, wherein the rounded top end of the pin is in the form of a ball, the housing has an internal wall providing a hole the wall of which presents a bearing surface to the ball end of the pin, the ball being of a greater diameter than the pin.

Claim 7

In a rotary tool as in claim 4, wherein an upper end surface of the wall surrounding the port defines a seat for the safety valve, the free end of the safety valve is adapted to engage in its closed position upon the seat, and the trip pin has a set position in which its ball end abuts the safety valve at a level above that of the seat at which level the valve is deflected away from the seat.

Claim 8

In a rotary grinding tool including a rotary air motor having a rotor shaft adapted at a lower end for attachment to a grinding wheel, an inlet port for admitting live air to the motor, a first valve controlling air flow through the port to the motor, a speed governor attached to an upper end of the shaft responsive to development of a predetermined level of centrifugal force by the motor to regulate operation of the valve; a safety valve having one position in which it is closed upon the port shutting off air flow to the motor, and having a normal open position raised from the port allowing live air flow through the port to the motor, a releasable trip pin normally stressing the safety valve from its closed position to its open position, the valve being adapted upon release of the trip pin to return to its closed position, and flyweight tripping means carried by the governor having response to a predetermined higher level of centrifugal force developed by the motor to release the trip pin from the safety valve and as a consequence release its stressing force from the latter, wherein the safety valve is a leaf spring fixed at one end upon an internal shoulder of the housing of the tool and having an opposite free end movable to and from closing relation to the port; wherein the trip pin is disposed in parallel relation to the axis of the governor and in radial spaced relation thereto, and the flyweight tripping means comprises a spring fixed at one end to a body member of the governor and having a free end to which a weight is attached.

Claim 9

In a rotary grinding tool including a rotary air motor having a rotor shaft adapted at a lower end for attachment to a grinding wheel, an inlet port for admitting live air to the motor, a first valve controlling air flow through the port to the motor, a speed governor attached to an upper end of the shaft responsive to development of a predetermined level of centrifugal force by the motor to regulate operation of the valve; a safety valve having one position in which it is closed upon the port shutting off air flow to the motor, and having a normal open position raised from the port allowing live air flow through the port to the motor, a releasable trip pin normally stressing the safety valve from its closed position to its open position, the valve being adapted upon release of the trip pin to return to its closed position, and flyweight tripping means carried by the governor having response to a predetermined higher level of centrifugal force developed by the motor to release the trip pin from the safety valve and as a consequence release its stressing force from the latter, wherein the safety valve is a leaf spring fixed at one end upon an internal shoulder of the housing of the tool and having an opposite free end movable to and from closing relation to the port; wherein the trip pin is disposed in parallel relation to the axis of the governor and in radial spaced relation thereto, and the flyweight tripping means comprises a spring fixed at one end to a body member of the governor and having a free end to which a weight is attached.