US3811514A

US3811514A - Pressure fluid operated tool

Info

Publication number: US3811514A
Authority: US
Inventors: K Karden; J Blomberg; H Elmessaar
Original assignee: Atlas Copco AB
Current assignee: Atlas Copco AB
Priority date: 1971-09-17
Filing date: 1972-09-14
Publication date: 1974-05-21
Anticipated expiration: 1991-05-21
Also published as: DE2245242B2; BR7206413D0; AU462346B2; SE355983B; ZA726083B; FR2154036A5; GB1354648A; AU4645672A; DE2245242A1; DE2245242C3; IT965312B; NL7212469A

Abstract

A pneumatic tool has a control valve with a cup-shaped elastomeric valving element disposed in a socket to cover a channel leading from the socket. The forward end of an air inlet forms the socket. The peripheral wall of the elastomeric element can be deformed by means of a radial rod to form between the elastomeric element and the socket a passage from the inlet to the channel.

Description

United States Patent Blomberg et al.

PRESSURE FLUID OPERATED TOOL Inventors: Jarl Joel Blomberg, Nacka; Heino Elme'ssaar, Lidingo; Karl Gosta Karden, Nacka, all of Sweden Atlas Copco Aktiebolag, Nacka, Sweden Filed: Sept. 14, 1972 Appl. No.: 289,162

Assignee:

Foreign Application Priority Data Sept. I7, 1971 Sweden 11827/71 US. Cl. 173/65 1m. Cl. B25d '17/14,E21 7/00 Field of Search 404/13;; 1o4/13, 14;

References Cited UNlTED STATES PATENTS 7/l960 Doedon 173/59 1451 May21, 1974 Sears 173/64 Lear 173/64 Primary Examiner-Geo. V. Larkin Attorney, Agent, or Firm-Flynn & Frishauf [5 7] ABSTRACT 29 Claims, 8 Drawing Figures Iiijiii'ii) Pmmmmm m4 318111514 SHEET 1 BF 2 Fig. I

PRESSURE FLUID OPERATED TOOL This invention relates to a pressure fluid operated tool of the kind that includes a control valve. As examples of such tools can be mentioned chipping hammers, nut runners, screw drivers, grinding machines and blowing nozzles. Usually,'the control valve in such tools is a poppet valve or a slide valve, and with such a valve it can be difficult to moderate the flow of pressure fluid, especially when a very limited air flow is desired.

In certain tools, two or more separate valve functions are needed. In a chipping hammer, for instance, one control is needed for the impact motor and one control for the separate steady blowing for the removal of the cuttings or chips on the surface being worked. Normally, two separate poppet valves are used for this purpose; an expensive and cumbersome solution.

It is an object of the invention to provide for an improved valve function in pressure fluid operated tools by means of a simple and inexpensive control valve which, furthermore, permits a plurality of valve functions, and to this end the invention has'been given the characteristics stated in the claims.

The invention. will be further described with reference to the accompanying drawings which show a chipping hammer as-an embodiment of the invention. FIG.

1 is a longitudinal section through the chipping hammer; FIG. 2 is a modified form of the back head and the control valve of the chipping hammer. FIG. 3 is an enlarged longitudinal section, taken along line 33 in FIG. 4, through the valving element of the control valve, the valving element being the same as in FIG. 1. FIG. 4 is a cross section along line 4--4 in FIG. 3. FIGS. 5 and 6 are also cross sections along line 4-4 in FIG. 3 but they show the valving element deformed to permit compressed air to pass on the outside thereof.

FIG. 7 is a section along line 77 in FIG. 80f a valving element which is a modification of that shown'in FIG. 3. FIG. 8, finally, is a cross section along line 88 in FIG. 7.

The chipping hammer shown in FIG. 1 has a housing in two parts; the forward part 12 containing an impact motor 50 and the rear part 13 containing a control valve 15. The impact motor 50 has a hammer piston 16 controlled by a disc valve 17 which supplies compressed air alternately to the working chamber formed at the rear of the piston and to a channel 18 leading to the working chamber formed in front of the'piston so as to provide for the reciprocating movement of the piston. These working chambers vent alternately to an exhaust channel 20 during the reciprocation of the hammer piston. In the front end of the tool, a chisel 21 is inserted and held by a retainer 22 so that the hammer piston will strike the end face 23 of the chisel during its reciprocation.

Through a fitting 24, compressed air is supplied axially to an inlet 25, the forward portion of which forms a socket 26 for a cup-shaped elastomeric valving element 27. A channel 28 leads from the peripheral wall of the socket 26 to a cylindrical chamber 29 from which compressed air can be supplied through a channel 30 to the rear side of the disc valve 17 and to the forward side of the disc valve-through a channel 31 indicatedby dotted lines in FIG. 2. Another channel 32 leads from the peripheral wall of thesocket 26 to the exhaust channel 20.

The valving element 27 is molded for instance in polyurethane rubber as a one-piece element and it has a cylindrical wall 33 (FIG. 3) and a flat bottom 34 with an excentrically placed axially extending cylindrical heel 35. The valving element 27 is hollow so that its peripheral surface 33 is forced against the socket 26 not only by its own spring action but also by the air pressure to close the two

channels

28, 32. Axially, the valv-' ing element 27 is held in place by being forced against the bottom 45 of the socket 26 by virtue of the air pressure. Associated with the

channels

28, 32, there are

rods

36, 37 which are slidable in respective

radial bores

48, 49. By means of

handles

38, 39 pivotably mounted on fixed

pivots

40, 41, these

rods

36, 37 can be individually forced inwardly to deform the cylindrical wall 33 of the valving element so that axial compressed air passages to the

channels

28, 32 are formed between the valving element 27 and its socket 26. In FIG. 5 is shown the deformation of the valving element 27 when the rod 36 is forced somewhat inwardly by means of the handle 38 so that a restricted axial passage is formed, and in FIG. 6 the valving element is shown in the form it takes up when the rod 36 is forced fully inwardly so that the impact motor operates with full pressure. In the embodiment of FIG. 1 the longitudinal axis 54 of the channel 32 intersects atan acute angle a with the-axis of the socket 26. The same condition exists for channel 28 in FIG. 1.

Turning of the valving element 27 is prevented by means of the heel 35 so that two

feathers

42, 43, integral with the valving element, will always be located

adjacent therods

36, 37 to increase theclosing force of the valving element and axially stiffen the latter.

The valving element 27 can be replaced in a very simple way. After screwing off a bushing 44 in which the fitting 24 is screwed, one can blow out the valving element by supplying compressed air backwardly through the channel 20, andthen another valving element can be forced down through the inlet 25 and into the socket 26. To ensure the blowing-out of the valving element, there is a narrow channel 47 between the channel 20 and the bottom 45 of the socket.

In FIGS. 7 and 8, a valving element is-shown which has an additional axial stiffener in the form of a U- shaped wire 46 inserted in the valving element from the underside thereof. In the embodiment of FIGS. 7 and 8, the U-shaped wire 46 extends through

bores

51, 52 in the wall portions of the valving element 27- in the vicinity of the

stiffening features

42, 43. The wire 46 can be used with or without the

stiffening feathers

42, 43. The bottom of the U-shaped wire 46 is in a recess 53 in the bottom of the valving element 27 so that the bottom surface of valving element "27 is flat.

In FIG. 2, the valving element 27 is conical .instead of cylindrical. This form permits the channel 28 to be parallel with the inlet 25.

What we claim is:

. l. A pressure fluid operated tool having a control valve that comprises a valving element in the form of a hollow elastomeric body which is open towards a pressure fluid inlet and disposed in a socket abutting against the peripheral wall of said socket, a channel which opens flush with said wall ofsaid socket and leading from said wall of said socket, the axes of said socket and channel having an angle therebetween of less than said hollow elastomeric body covering the channel opening and isolating said channel opening from said inlet, means located upstream of said channel opening and arranged to deform the peripheral wall of the elastomeric body in a direction substantially transverse to said peripheral wall of said socket so as to form between the elastomeric body and the socket a substantially axial pressure fluid passage from said inlet to said channel.

2. A tool as defined in claim 1 in which the elastomeric body is axially supported by a supporting surface against which it is forced by the pressure fluid acting on 3. A tool as defined in claim 2 in which the elastomeric body is cup-shaped.

4..A tool as defined in claim 3 in which the support surface comprises the bottom of the socket, the bottom of the elastomeric body abutting against the bottom of the socket.

5. A tool as defined in claim 4 in which the socket is rotation-symmetrical and co-axial with said inlet.

6. A tool as defined in claim 5 in which the socket is cylindrical.

7. A tool as defined in claim 1 in which the elastomeric body is provided with axially oriented'stiffening means associated with said means for deforming the elastomeric body.

8. A tool as defined in claim 7 in which the elastomeric body and socket are provided with engaging means to prevent turning of the elastomeric body in said socket.

9. A tool as defined in claim 8 in which said means to prevent turning of the elastomeric body comprises an eccentrically disposed axial heel on said elastomeric body mating with a corresponding recess in the bottom of the socket.

10. A tool as defined in claim 7 wherein said stiffening means comprises a metallic member stiffening at least a wall portion of the elastomeric body.

11. A tool as defined in claim 10 wherein said metallic member is within the wall portion being stiffened.

12. A tool as defined in claim 1 in which said means for deforming the peripheral wall of the elastomeric body comprises a substantially radially disposed rod which is slidable in a bore that ends in the socket upstream of the center of the opening of said channel and which is displaceable in its longitudinal direction.

13. A tool as defined in claim 12 in which an operating handle in the form of a lever is arranged for displacing said rod.

14. A tool as defined in claim 1 in which a plurality of channels lead from the peripheral wall of the socket and a means for deforming the elastomeric body is associated with eachchannel for selectively communicating said plurality of channels with said inlet. I

15. A tool as defined in claim 14 comprising a pressure fluid driven impact motor to which one of said channels leads, another channel leading to the fore portion of the tool so as to provide for the cleaning by blowing of the work-piece. v

16. A tool as defined in claim 15 in which said means for deforming the elastomeric body comprises two rods mounted diametrically opposite each other and slidable in their longitudinal direction in respective bores that end in the socket upstream of the center of the openings of the respective channel openings.

l7 Atool as defined in claim 1 wherein said peripheral wall of said socket defines a substantially cylindrically shaped socket and the elastomeric body is substantially cylindrically shaped.

18. A tool as defined in claim 1 wherein said peripheral wall of said socket defines a substantially conically shaped socket and the elastomeric body is substantially conically shaped.

19. A pressure fluid operated tool having an elongated housing, said housing including a back head, a motor in said housing, a central longitudinal blind bore in said back head, an inlet comprising a hose fitting at the outer rear end of said bore, the blind end of said bore forming a socket for a valving element in the form of a hollow elastomeric body, said hollow elastomeric body abutting against the peripheral wall of said socket and being open towards the hose fitting, a channel which opens flush with said wall of said socket and leading from said wall of said socket to said motor, said hollow elastomeric body covering the channel opening and isolating said channel opening from said inlet, means arranged to deform the peripheral wall of the elastomeric body in a direction substantially transverse to said peripheral wall of said socket so as to form between the elastomeric body and the socket a substantially axial pressure fluid passage from said inlet to said channel.

20. A tool as defined in claim 19 in which the elastomeric body is cup-shaped and is supported by a supporting surface' against which his forced by the pressure of fluid acting on it.

21. A tool as defined in claim 19 in which the elastomeric body is provided with axially oriented stiffening means associated with said means for deforming the elastomeric body. I

22. A tool as defined in claim 21 in which the elastomeric body and socket are provided with engaging means to prevent turning of the elastomeric body in said socket.

23. A tool-as defined in claim 19 in which said means for deforming the peripheral wall of the elastomeric body comprises a substantially radially disposed rod which is displaceable in its longitudinal direction.

24. A tool as defined in claim 23 in which said rod is slidable in a bore that ends in the socket upstream of the center of the opening of said channel.

25. A tool as defined in claim 19 in which the axes of the socket and the channel intersect in an acute angle.

26. A tool as defined in claim 19 in which a plurality of channels lead from the peripheral wall of the socket anda means for deforming the elastomeric body is as sociated with each channel for selectively communicating said plurality of channels with said inlet.

27. A tool as defined in claim 19 wherein said peripheral wall of said socket defines a substantially conically shaped socket and the elastomeric body is substantially conically shaped.

28. A tool as defined in claim 1 wherein the axes of said socket and said channel intersect at an acute angle.

29. A tool as defined in claim 1 wherein the axes of said socket and said channel are substantially in parallel with each other.

Claims

1. A pressure fluid operated tool having a control valve that comprises a valving element in the form of a hollow elastomeric body which is open towards a pressure fluid inlet and disposed in a socket abutting against the peripheral wall of said socket, a channel which opens flush with said wall of said socket and leading from said wall of said socket, the axes of said socket and channel having an angle therebetween of less than 90*, said hollow elastomeric body covering the channel opening and isolating said channel opening from said inlet, means located upstream of said channel opening and arranged to deform the peripheral wall of the elastomeric body in a direction substantially transverse to said peripheral waLl of said socket so as to form between the elastomeric body and the socket a substantially axial pressure fluid passage from said inlet to said channel.

2. A tool as defined in claim 1 in which the elastomeric body is axially supported by a supporting surface against which it is forced by the pressure fluid acting on it.

3. A tool as defined in claim 2 in which the elastomeric body is cup-shaped.

4. A tool as defined in claim 3 in which the support surface comprises the bottom of the socket, the bottom of the elastomeric body abutting against the bottom of the socket.

6. A tool as defined in claim 5 in which the socket is cylindrical.

7. A tool as defined in claim 1 in which the elastomeric body is provided with axially oriented stiffening means associated with said means for deforming the elastomeric body.

14. A tool as defined in claim 1 in which a plurality of channels lead from the peripheral wall of the socket and a means for deforming the elastomeric body is associated with each channel for selectively communicating said plurality of channels with said inlet.

15. A tool as defined in claim 14 comprising a pressure fluid driven impact motor to which one of said channels leads, another channel leading to the fore portion of the tool so as to provide for the cleaning by blowing of the work-piece.

17. A tool as defined in claim 1 wherein said peripheral wall of said socket defines a substantially cylindrically shaped socket and the elastomeric body is substantially cylindrically shaped.

20. A tool as defined in claim 19 in which the elastomeric body is cup-shaped and is supported by a supporting surface against which it is forced by the pressure of fluid acting on it.

21. A tool as defined in claim 19 in which the elastomeric body is provided with axially oriented stiffening means associated with said means for deforming the elastomeric body.

23. A tool as defined in claim 19 in which said means for deforming the peripheral wall of the elastomeric body comprises a substantially radially disposed rod which is displaceable in its longitudinal direction.

26. A tool as defined in claim 19 in which a plurality of channels lead from the peripheral wall of the socket and a means for deforming the elastomeric body is associated with each channel for selectively communicating said plurality of channels with said inlet.