FR2519575A1 - PERCUSSION TOOL - Google Patents

Abstract

A. PERCUSSION TOOL CONSISTING OF A PECE CASE WITH A BORE IN WHICH IS MOUNTED A BELT INTENDED TO CREATE A SHOCK, AND A FRONT CYLINDER INCLUDING AN ANVIL AND A SCISSOR RECEIVER INTENDED TO RECEIVE A PLURALITY OF SCISSORS AMOUNTED COAXIALLY IN RELATION TO THE OTHER. B. BOX 1 INCLUDES A PARTIALLY REDUCED EXTERNAL CIRCUMFERENCE TO MAKE A REDUCED DIAMETER PART 32. A THICKNESS PART 36 IS MOUNTED ON THE REDUCED DIAMETER PART. THE THICKNESS PART 36 PROJECTS RADIALLY INTO THE INTERIOR FROM A PROTECTIVE SHEATH 35 MOUNTED ON THE EXTERNAL CIRCUMFERENCE OF THE BOX 1 SO AS TO BE ABLE TO MOVE IN THE AXIAL DIRECTION. BUFFER SPRINGS 37 ARE INTERPOSED RESPECTIVELY BETWEEN THE TWO ENDS OF THE THICKNESS PART 36 AND THE TWO ENDS OF THE PART OF THE REDUCED DIAMETER 32, A RETURN SPRING 11 IS PROVIDED TO RECALL THE ANVIL 13. THE SCISSOR RECEIVER 7 AND THE BELIER 2 ARE INTERPOSED BETWEEN A FRONT FACE OF THE ANVIL 13 AND A SPRING SEAT 5 PROVIDED AT THE FRONT END OF THE FRONT CYLINDER 4. C. APPLICATION: PERCUSSION TOOL FOR CUTTING STONE, FOR EXAMPLE.

Description

The present invention relates to a percussion tool for

  so much of shredding or grinding the surface of a piece

  metal, stone or other It relates in particular to a perfection-

  percussion tool of the type in which the striking is effected by the action of compressed air while the return

  under spring elastic force for the purpose of

next strike.

  Known percussion tools have a disadvantage in

  they cause operator fatigue because their use

  during the strike operation is always accompanied by

of vibrations.

  In view of this drawback of known percussion tools, the provision of

  of the present invention is intended to absorb the

  shocks that would otherwise be transmitted to an axially

  The present invention makes it possible to minimize the creation of

  this poses a problem for known tools, thanks to a handle attached to the outer circumference of the body of

  the tool and springs attached to the handle.

  The present invention also relates to a shock absorber for a percussion tool used to cut by splintersor to grind the surface of a workpiece, for example metal or stone.

  When the cutting operation is done by hand, the operation

  holding the percussion tool, the front end of which carries a chisel driven by an action of an engine or compressed air to strike the surface of a part

  and cut by the tip of the chisel, the shocks coming from the

  the shocks coming from the surface of the part are transmitted both to the operator's hands These shocks transmitted accelerate the fatigue or cause an interruption of the blood circulation of the operator This problem constitutes a

  disadvantage of percussion tools of the prior art.

  Given this defect of the tools of the prior art, the device according to the present invention is intended to absorb shocks

  transmitted to the body of the percussion tool by the presence of res-

  spells Absorbed shocks are transmitted to a protective sheath through a handle attached to the outer circumference of the body

  of the tool and springs attached to this handle.

  An embodiment of the present invention is hereinafter described by way of example with reference to the accompanying drawings in which: Figure 1 is a sectional view of the impact tool prior to the striking operation; Figure 2 is a sectional view of the impact tool after the striking operation, part partially broken away; Figure 3 is a plan view of the overall construction of the tool; Figure 4 is a sectional view along the line A-A of Figure 3;

  FIG. 5 is an elevational view taken from the end of

  rear mite; and FIG. 6 is an elevational view, partially in

cut, showing the lever lowered.

  We will first describe an embodiment of the present

  invention with reference to Figures 1 and 2.

  A cylindrical housing 1 constitutes the body of the tool to be

  A ram 2 is mounted so that it can move forwards under the action of compressed air. The ram 2 can reciprocate in a cylindrical bore 3 excavated axially in the housing 1 A front cylinder 4 is fixed on the

  front part of the housing 1 in alignment with the axis of the bore 3.

  The front cylinder 4 has its front end bent radially inward to form a spring seat 5 while providing

  a large opening 6 in the center of this seat 5.

  A scissor receiver 7 has a substantially C-shaped longitudinal section. The receiver 7 comprises a bottom pierced with ten holes 8 or more, traversed by the scissors 10.

  all have a head-shaped base 9 Between the underside

  7 of the scissor receiver 7 and the spring seat 5 is interposed with a return spring 11 which urges the receiver 7

  backward (that is to the right on the drawing).

  An anvil 13 is interposed between the open face of the receiver.

  7 and the front face of the housing 1 The anvil 13 is mounted in the front cylinder 4 so as to be able to move

  alternative The shock of the ram 2 mounted in the bore 3 is supported

  according to the same principle as that of an equilibrium ball, by the anvil 13 so that the live force of the ram 2 is transmitted.

  scissors 10 A part, of reduced diameter, 13 has provided for the ex-

  front end of the anvil 13, is pushed into the receiver 7, when the receiver back, and strikes directly on the heads 9 scissors, when the scissors 10 back on the other side,

  the anvil 13 comprises a rear portion 13b in the form of adhesive

  intended to stabilize the directional position of the

  me 13 A blind hole 15 is dug in the ram 2 since

  the back of it The ram 2 includes a sensitive part-

  intermediate member pierced with radial air intake holes 16 and a larger diameter rear end 18 connected to the

  intermediate portion by a portion 17 forming a shoulder.

  This portion 17 comes into contact with a stop 19 forming corresponding shoulder formed in the intermediate portion of the bore 3 The bore 3 is larger in the radial direction to

the back of the stop 19.

  A rear member 20 is attached to the rear end of the housing.

  A valve chamber 21 is provided in the rear member and comprises a control spool 23 provided with a rod 22 which protrudes outwardly from the intermediate portion of the rear member 20. air 24 is provided at the rear end of the rear member 20 and a channel 25 provides communication between the air inlet 24 and the other

  end of the rear member 20 through the chamber of sou-

  Pope 21 air supply channels 26 are provided axially-

in the case 1.

  A shoulder 30 is provided substantially at one end of the

  housing 1 A shoulder 31 is formed at the front part of the body

  The housing 1 comprises a circumferential surface

  exterior of which a part of reduced diameter 32 is

  located between the two shoulders 30 and 31.

  A protective sheath 35 covers the circumferential surface

  outside of the front cylinder 4, the housing 1 and the rear organ

  20 and comprises an inner circumference having a thickened portion 36 which cooperates with the reduced diameter portion 32 The thickened portion 36 is shorter than the portion of reduced diameter 32 Buffer springs 37 are interposed respectively between the thickened portion 36 and the shoulders 30 and 31 to urge the casing 1 and the protective sheath 35 one by

  relative to each other in the axial direction.

  The valve stem 22, comprising an upper end bearing a roller 39 pivoting, projects from a C 38 part provided on the rear part of the sheath 35 A control lever is articulated on both sides of the rear part of the sheath 35 Vent holes 41 open into the part

  the largest of the bore 3 and occupy symmetrical positions

  In this embodiment, these discharge ports 41 communicate, via the rear member 20, with

  the outside of the body of the percussion tool.

  We will now describe the functioning of this mode of

lisation.

  The compressed air supplied from the outside arrives at the air intake 24 of the rear member 21 The ends of the scissors 10 are applied to the surface 50 of a workpiece When the lever is pressed 40 to open the control valve 23, the compressed air passes through the communication channel 25 and the air supply channels to gain the interior of

the bore 3.

  If the percussion tool is then directed downward, the

  bind 2 comes to occupy its left position, looking at the drawing, thanks to its own weight If the air acts on the shoulder 17 of the ram 2, it moves to the right (that is to say

  backwards), looking at the drawing.

  When the air supply channels 26 and the air intake holes 16 approach the state where they are communicated between

  them, the compressed air comes out of the holes 16 to penetrate to the in-

  inside the blind hole 15, which has the effect of increasing the

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  pressure in this hole 15, that is to say the pressure acting

  on the back of the ram 2 As a result, the ram 2 is thrown forward to strike the anvil 13

  ram 2 is transmitted to the scissors receiver 7 via

  1 to project the receiver 7 forward to strike the heads 9 of the scissors 10 passing through the scissor receiver so that the scissors 10 can perform size operations by splinters, etc. When the ram occupies its position before, the blind hole 15

  is in communication with the discharge ports 41, by means of

  intermediate the air intake holes 16, so that the return spring 11 moves the receiver 7 backwards However, the shoulder portion of the ram 2 is subjected to the pressure of

  compressed air in a similar way to the condition just described.

  write, so that it recoils under the action of compressed air in order to

the next strike operation.

  During this operation, the shock created when the ram 2 hits the receiver 7 via the anvil 13, and the shock created when the ends of the scissors 10 hit the surface of the workpiece 50 are transmitted to the housing 1. shocks are transmitted as low vibrations by the springs 37 to the

  protective sheath 35 covering the circumferential surface ex-

  1 of the casing 1 so as to be able to move in the axial direction. Thanks to this arrangement, the fatigue of the operator holding the

  protective sheath 35 is reduced.

  We will now describe a second embodiment of the device according to the invention, namely a damper for

  percussion tool, with reference to Figures 3 to 6.

  A first lever 2 is articulated on the rear part of a casing 1 and at the same time serves as a handle.

  the handle 2 to open a control valve 3, air

  coming from the outside springs from an air inlet 4 and

  crosses a control valve 3 to gain a food channel.

  5, made in the housing 1, to project forward a ram 7 mounted in a cylindrical bore 6 extending

  in the axial direction in the housing 1.

  A scissors-holder 3 is axially movable by the open side of a pressure chamber 12 formed in the housing 1 which has an opening at its forward end. An anvil 14 is mounted at the rear of the scissors holder 13. so that it can move in the axial direction Thus, when the ram 7 hits the anvil 14 and it advances to hit the scissor holder 3, a chisel (not shown) mounted in the chisel holder 13 can

  perform a sizing operation by its tip.

  A reduced diameter portion 20 is made at a substantially middle portion of the outer circumference

  of the housing 1 Shoulders 21 and 22 are formed on the circumference

  1, at the two ends of the reduced diameter portion 20, two notched grooves 24 are hollowed out in the rear part of the housing 1 in which the first lever 1 is mounted by means of a pin 25. Protective sheath 35 is mounted on the outer circumference of the casing 1 so as to be able to move in the axial direction. The sheath 35 has a thickened portion 26 which protrudes radially inwardly from the inner circumference of the sheath 35. a longer length

  in the axial direction as that of the diameter portion

  20 of the previous housing 1, so as to fit into the

reduced diameter 20.

  Elastic elements 27 and 27 ', such as return springs for example, are interposed elastically between the

  two ends of the reduced diameter portion 20 and the two ex-

  trenches of the thickened part 26, respectively A tamper-evident sleeve

  pon 28, a strong shock-absorbing action is mounted with

  the elastic element 27 on the side of the opening 11.

  A notched portion 29 is formed at one end of the rear portion of the protective sheath 35 to allow the

  control valve 3 to pass through a second lever 37 coagis-

  with the first lever 2 comprises an articulated rear end

  pinned against a pin 31 on supports 30 which protrude, on both sides, the rear end of this portion 29 The first lever 2 is mounted in the second lever 37 which, in turn, can

  move in the axial direction with the protective sheath 35.

  The operation of this second embodiment of the present invention

  This invention is described below.

  As seen in FIG. 6, when the first and second levers 2 and 37 are depressed, they move downwardly against the force of an elastic spring 3a which is part of the control valve 3 The control valve 3 opens so that compressed air from the outside enters abruptly into

  the bore 6 to project forward the ram 7 which comes frap-

  For the scissors holder 13 via the anvil 14 Thus, the surface of the workpiece is cut and finished by the tip of the chisel

carried by the scissors holder 13.

  The shock created when the ram hits the scissor carrier through the anvil and the shock transmitted from the surface of the workpiece by the chisel are both transmitted first to the casing 1. However, the operator in his hand the

  protective sheath 35 which is mounted on the outer circumference

  the casing 1 so as to be able to reciprocate. These shocks are not therefore transmitted directly

  in the hands of the operator More precisely, because the

  elastic members 27 and 27 'and the buffer sleeve 28 are interposed respectively between the two ends of the thickened portion 26, the thickening of which protrudes radially inwards on the inner circumference of the protective sheath 35, and the two ends of the reduced diameter portion 20 formed in the housing, the axial shocks, which would otherwise be transmitted to the housing 1, are substantially absorbed by the elastic members

  27 and 27 'so that they are transmitted only in the form of

  vibrations in the hands of the operator holding the sheath

35.

  As already mentioned, according to the present invention, the thickened portion 26, the thickening of which extends radially inwardly from the inner circumference of the sheath.

  protection 35, is provided on the outer circumference of the

  tier 1 so that it can move in the axial direction and is

  mounted on the reduced diameter portion 20 formed on the circumference

  The elastic elements 27 and 27 'are respectively sandwiched between the two ends of the housing.

  the thickened portion 26 and the two ends of the diagonal portion

  As a result, the steep axial shocks that would otherwise be transmitted to the housing 1 are

  absorbed by the elastic members 27 and 27 'before being

  put in protective sheath 35 Even if the operator holds the

  sheath 35 during splinter size operations, it will undergo

  less fatigue allowing him to do a better job.

  It goes without saying that many modifications can be made to the device described and represented without

depart from the scope of the invention.

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Claims (6)

  1 percussion tool comprising a casing drilled with a bore   cylindrical geometry in which is mounted a ram intended to create a shock, and a front cylinder comprising an anvil and a scissor receiver for receiving a plurality of scissors fixed co-axially with respect to each other, characterized in that furthermore includes:   the housing (1) has a partial outer circumference-   decreased to make a smaller diameter part (32)   a thickened portion (36) mounted on the portion of diameter   duct (32) and extending radially inwardly from a protective sheath (35) mounted on the outer circumference of the casing (1) so as to be movable in the axial direction of the buffer springs (37) being interposed respectively between both ends of the thickened portion (36) and both ends of the reduced diameter portion (32); and a return spring (11) for recalling the anvil (13);   the scissors receiver (7) and the ram (2) being interposed between a front face of the anvil (13) and a spring seat (5)   provided at the front end of the front cylinder (4).   2 Shock absorber for use in a compression tool   characterized in that it comprises a cylindrical bore (3) in which is mounted a ram   (2) for creating a shock and a pressure chamber (6) containing   an anvil (14) and a scissors-holder (13) mounted together   axially in a housing (1); said housing (1) comprising a partially diminished outer circumference for making a portion of reduced diameter (20);   a thickened portion (26) mounted on the reduced diameter portion (20) and projecting radially inwardly from   a protective sheath (35) mounted on the outer circumference   re housing (1) so as to be able to move in an axial direction; and   elastic elements (27, 27 ') being respectively interposed   between two ends of the thickened part (26) and the   two ends of the reduced diameter portion (20).   3 impact tool according to claim 1 or 2, characterized   in that a rear member (21) is fixed on the housing (1) and comprises closing means (22) for supplying compressed air to a surface of the ram (2) in operation in order to animate the latter of an alternative movement to create a shock.   4 impact tool according to claim 3, characterized   in that the housing (1) and the protective sheath (35) are cy-   lindrical and are held in relation to each other by   the rear member (20) screwed into the housing (1).   Impact tool according to claim 1 or 2, characterized   Iridescent in that the ram (2) comprises a portion of diameter   in communication with a fluid under pressure during a   return and comprising an opening (16) for   fl uid the fluid under pressure to reverse the direction of displacement   ram (2) and to create a shock on the anvil (13).   Impact tool according to claim 5, characterized   in that the fluid under pressure passes through axial and radial channels pierced holes in the housing (1).   Impact tool according to claim 3, characterized in that it further comprises an evacuation orifice (41) intended   to evacuate the compressed air supplying the ram (2) in order to impose rhyme a movement back.