Pneumatic impact wrench

Abstract

The invention discloses a pneumatic impact wrench, comprising an air motor, an air intake mechanism, a striking mechanism and a striking shaft. The air motor rotates to the striking mechanism through a rotor output, and the striking mechanism drives the striking shaft to form a rotational motion. The pneumatic impact wrench also comprises a fixed torque mechanism, which comprises a rotating block, a fixed torque spring and an ejector pin. In normal operation, the rotating block rotates with the rotating drum under the action of inertia. When the torque at the end of the striking shaft reaches a set value, the rotating speed of the rotating drum decreases, and the rotating block rotates relative to the rotating drum under the action of inertia, and drives the positioning pin to be relatively positioned. At this time, the ejector pin falls into the pinhole of the positioning pin under the action of the axial spring and undergoes axial displacement, and drives the air intake cap to move, and at this time, the air intake cap closes the air inlet of the air intake mechanism. The resistance of the spring can be adjusted by adjusting the nut. The greater the spring force, the greater the torque output by the striking shaft.

Description

Technical Field

[0001] The invention relates to the technical field of pneumatic wrenches, and in particular to a pneumatic impact wrench with a torque-fixing function. Background Art

[0002] Pneumatic impact wrenches use high-pressure gas (usually 6.2Kgf) to drive the pneumatic motor mechanism to rotate, and then output to the striking mechanism through the rotor, and the striking mechanism drives the striking shaft to form a reciprocating forward and backward and rotating motion. It is widely used in municipal construction, metallurgy, building assembly / manufacturing, railways, shipbuilding, automobiles, and chemicals. However, existing pneumatic impact wrenches generally do not have a torque setting function and need to manually control the output torque. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a pneumatic impact wrench with a fixed torque function and convenient output torque adjustment.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: a pneumatic impact wrench, including an air motor, an air intake mechanism, a striking mechanism and a striking shaft. The air motor rotates to the striking mechanism through a rotor output, and the striking mechanism drives the striking shaft to form a rotational motion. It also includes a fixed torque mechanism, which includes a rotating block, a fixed torque spring and an ejector pin. The rotating block is arranged on the striking mechanism through a pin shaft parallel to the axis of the air motor. A positioning pin perpendicular to the pin shaft is arranged on the rotating block, and a pinhole is arranged on the positioning pin. The ejector pin is arranged along the axis direction of the air motor, one end of which is located at the positioning shaft, and the other end extends out of the air inlet of the air intake mechanism, and the end is provided with an air intake cap for In order to close the air inlet, an axially arranged spring is also mounted on the ejector pin, and a protrusion is arranged on the outer peripheral surface of the ejector pin. The spring always contacts the protrusion to give the ejector pin an axial thrust, which pushes the ejector pin toward the locating pin; the torsion spring is arranged perpendicular to the pin shaft, one end of the torsion spring is connected to the rotating block, and the other end is connected to the striking mechanism through an adjusting nut, and the adjusting nut is used to adjust the compression degree of the spring and thus adjust the spring elastic force; the rotating block rotates with the striking mechanism under the action of inertia, and when the rotation speed of the striking mechanism suddenly decreases, the rotating block rotates relative to the striking mechanism, and the ejector pin falls into the pinhole under the action of the axial spring and undergoes axial displacement, at which time the air inlet cap closes the air inlet of the air inlet mechanism.

[0005] Furthermore, a limiting column is provided on the striking mechanism, and an axial sliding groove is provided on the positioning pin. The limiting column slides along the sliding groove relative to the positioning pin and limits the position of the positioning pin.

[0006] Furthermore, the striking mechanism includes a rotating drum, a rotor and two striking blocks located in the rotating drum. A connecting shaft is provided at the end of the rotating drum to connect to the pneumatic motor or the reduction mechanism. The rotor is driven to rotate by the rotating drum. Two notches are provided on the rotor. The ends of the striking blocks are located in the notches. The inner side wall of the striking block is curved, and the outer side wall cooperates with the inner wall of the rotating drum. A rotating shaft passing through the striking block is also provided on the striking block. The rotating shaft rotates synchronously with the rotating drum, and the striking block can swing around the rotating shaft; two protrusions are provided on the striking shaft, and the striking block can drive the protrusions to rotate, thereby driving the striking shaft to rotate.

[0007] Furthermore, a buffer spring is provided axially between the end of the positioning pin and the striking mechanism.

[0008] From the above technical solution, it can be seen that the present invention has the following advantages: the output torque can be quickly and conveniently set by the rotating block, the fixed torsion spring and the adjusting nut. When the output torque reaches the set value, the air inlet cap closes the air inlet and the pneumatic motor stops rotating. The adjustment control is convenient. The elastic force of the spring is set by the adjusting nut. The greater the elastic force of the spring, the greater the displacement of the positioning pin and the corresponding torque. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present invention will be further described below in conjunction with the accompanying drawings.

[0010] Figure 1 is a cross-sectional view of the present invention;

[0011] Figure 2 A diagram showing the connection relationship between the striking mechanism and the fixed-twist mechanism in the present invention;

[0012] Figure 3 The schematic diagram of the fixed torque mechanism in the present invention. DETAILED DESCRIPTION

[0013] The specific implementation modes of the present invention are described in detail below with reference to the accompanying drawings.

[0014] like Figure 1 , Figure 2 and Figure 3The pneumatic impact wrench of the present invention comprises a housing 1, in which an air motor 3, an air intake mechanism 5, a striking mechanism and a striking shaft 21 are arranged. The air motor 3 rotates to the striking mechanism through the rotor output, and the striking mechanism drives the striking shaft to form a rotational motion, wherein the air motor and the air intake structure are conventional technical means adopted in the technical field, and will not be described in detail here. The striking mechanism comprises a rotating drum 22, a rotor 25 and two striking blocks 23 located in the rotating drum, the end of the rotating drum 22 is provided with a connecting shaft connected to the air motor or the reduction mechanism, the rotor 25 is driven to rotate by the rotating drum, and two notches are arranged on the rotor, the end of the striking block 23 is located in the notch, the inner side wall of the striking block 23 is a curved surface, and the outer side wall cooperates with the inner wall of the rotating drum, and a rotating shaft 24 passing through the striking block is also arranged on the striking block, the rotating shaft 24 rotates synchronously with the rotating drum, and the striking block can swing around the rotating shaft; two protrusions are arranged on the striking shaft, and the striking block can drive the protrusions to rotate, thereby driving the striking shaft to rotate. This striking mechanism is a structure adopted by the present invention. Of course, the striking mechanism can also adopt other commonly used methods in the technical field, and the working principle of the striking mechanism will not be described in detail here. The present invention focuses on the fixed torque function, and its specific structure is as follows.

[0015] The present invention is equipped with a fixed torque mechanism, which includes a rotating block 43, a fixed torque spring 44 and a pin 41. The rotating block 43 is arranged on the rotating cylinder 22 of the striking mechanism through a pin 42 parallel to the axis of the air motor.

[0016] The locating pin 45 of the straight pin shaft 42 and the pinhole on the locating pin 45; the ejector pin 41 is arranged along the axial direction of the pneumatic motor, one end of which is located at the locating shaft and the other end extends out of the air inlet of the air inlet mechanism, and the end is provided with an air inlet cap 52 for closing the air inlet 51. The ejector pin 41 is also provided with an axially arranged spring 48, and a protrusion is provided on the outer peripheral surface of the ejector pin. The spring 48 always resists the protrusion and gives the ejector pin an axial thrust, which pushes the ejector pin 41 toward the locating pin; the torsion spring 44 is arranged perpendicular to the pin shaft 42, one end of the torsion spring 44 is connected to the rotating block 43, and the other end is connected to the rotating drum 22 of the striking mechanism through an adjusting nut 49, and the adjusting nut 49 is used to adjust the compression degree of the spring and thus adjust the spring elasticity, and the adjusting nut is arranged on the rotating drum 22.

[0017] The torque fixing principle of the torque fixing mechanism is as follows. During normal operation, the rotating block 43 rotates with the drum under the action of inertia. When the torque at the end of the striking shaft reaches a set value, the rotating drum speed decreases, and the rotating block 43 rotates relative to the drum under the action of inertia, and drives the positioning pin 45 to be relatively located. At this time, the ejector pin falls into the pinhole of the positioning pin under the action of the axial spring and axially displaces, and drives the air intake cap to move, and at this time, the air intake cap closes the air intake of the air intake mechanism. The resistance of the spring can be adjusted by adjusting the nut. The greater the spring elastic force, the greater the torque output by the striking shaft.

[0018] In addition, a limiting column 47 is provided on the striking mechanism, and an axial sliding groove is provided on the positioning pin 45. The limiting column 47 slides along the sliding groove relative to the positioning pin and limits the position of the positioning pin. The limiting column can limit the stroke of the positioning pin to prevent the positioning pin from being disengaged from the ejector pin. A buffer spring 410 is also provided along the axial direction of the positioning pin between the end of the positioning pin and the striking mechanism.

Claims

1. A pneumatic impact wrench, comprising an air motor, an air intake mechanism, a striking mechanism and a striking shaft, wherein the air motor rotates to the striking mechanism through a rotor output, and the striking mechanism drives the striking shaft to form a rotational motion, and further comprises a fixed torque mechanism, wherein the fixed torque mechanism comprises a rotating block, a fixed torque spring and an ejector pin, wherein the rotating block is arranged on the striking mechanism through a pin shaft parallel to the axis of the air motor, and a positioning pin perpendicular to the pin shaft is arranged on the rotating block, and a pinhole is arranged on the positioning pin; the ejector pin is arranged along the axis direction of the air motor, one end of which is located at the positioning shaft, and the other end extends out of the air inlet of the air intake mechanism, and the end is provided with an air intake cap for closing the air inlet, and the ejector pin is provided with a pinhole; A spring arranged axially is also provided, and a protrusion is provided on the outer peripheral surface of the ejector pin. The spring always abuts against the protrusion to give the ejector pin an axial thrust, and the thrust pushes the ejector pin toward the positioning pin. The torsion spring is arranged perpendicularly to the pin shaft, and one end of the torsion spring is connected to the rotating block, and the other end is connected to the striking mechanism through an adjusting nut, and the adjusting nut is used to adjust the compression degree of the spring and thus adjust the spring elastic force. The rotating block rotates with the striking mechanism under the action of inertia. When the speed of the striking mechanism suddenly decreases, the rotating block rotates relative to the striking mechanism, and the ejector pin falls into the pinhole under the action of the axial spring and undergoes axial displacement. At this time, the air inlet cap closes the air inlet of the air inlet mechanism. The striking mechanism is provided with a limiting column, and the positioning pin is provided with an axial sliding groove, and the limiting column slides along the sliding groove relative to the positioning pin to limit the position of the positioning pin; The striking mechanism comprises a rotating drum, a rotor and two striking blocks located in the rotating drum. A connecting shaft is provided at the end of the rotating drum to connect to an air motor or a reduction mechanism. The rotor is driven to rotate by the rotating drum. Two notches are provided on the rotor. The ends of the striking blocks are located in the notches. The inner side wall of the striking block is curved. The outer side wall matches the inner wall of the rotating drum. A rotating shaft passing through the striking block is also provided on the striking block. The rotating shaft rotates synchronously with the rotating drum, and the striking block can swing around the rotating shaft. Two protrusions are provided on the striking shaft. The striking block can drive the protrusions to rotate, thereby driving the striking shaft to rotate. A buffer spring is also arranged along the axial direction between the end of the positioning pin and the striking mechanism.

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