GB1597744A

GB1597744A - Highspeed hammers

Info

Publication number: GB1597744A
Application number: GB1533478A
Authority: GB
Original assignee: VORONWZH SP KONSTRUKE BJURO KU
Current assignee: VORONWZH SP KONSTRUKE BJURO KU
Priority date: 1978-04-19
Filing date: 1978-04-19
Publication date: 1981-09-09

Description

(54) IMPROVEMENTS IN OR RELATING TO HIGH-SPEED HAMMERS (71) We, VORONEZHSKOE SPETSIALNOE KONSTRUKTORSKOE BJURO KUZNECHNO-PRESSOVYKH MASHIN I AVTOMATICHESKIKH LINY, a Corporation organised and existing under the laws of the Union of Soviet Socialist Republics, of ulitsa Solnechnaya, 31-a Voronezh, U.S.S.R. do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to high speed anvilless hammers.

According to the present invention there is provided a high-speed anvilless hammer comprising a bed, guides provided on said bed, a frame supported on resilient means and mounted in said bed guides, a hammer head arranged to carry a working tool at its lower end, a die block mounted underneath said working tool, a drive for driving the hammer head axially towards the die block, said drive comprising a power chamber arranged to contain a working fluid, and a power cylinder with a piston including a piston rod, said cylinder being arranged for connection to a source of pressure fluid so that the piston can be moved to a lower position, said piston causing compression of the working fluid in the power chamber during such movement, the hammer head being mounted for reciprocating movement within a central bore of the piston rod and being subjected to a downwards force under the action of the pressure of the working fluid, a mechanism for releasably retaining the hammer head in an initial upper position during downwards movement of the piston, the stroke of said piston exceeding the distance between the die block and the lower end of said piston rod, whereby, when the piston is in a lowermost position, a closed zone is formed around said hammer head between said piston rod and the surface of said die block, in which zone deformation of a workpiece is effected by the working tool under the action of the compressed working fluid when the hammer head is released by the retaining mechanism, and means for returning the hammer head to its initial upper position after its working stroke.

In a preferred embodiment, the hammer head is guided in the piston rod by means of a bushing, the length of which exceeds the stroke of the hammer head.

Preferably, the means for returning the hammer head to its initial position comprises a flange mounted on the end of the piston rod so as to extend underneath an end face of the hammer head and to lift same when the piston is raised after the working stroke.

This arrangement permits the tool to be quickly withdrawn from contact with hot deformed metal, thereby increasing the durability of the tool and decreasing the duration of the working cycle of the hammer.

Preferably, provision is made for means for preventing axial rotation of the piston rod, in the form of guiding elements mounted on the frame and arranged to mate with guiding surfaces provided on the flange.

This arrangement improves the positioning of the working tool relative to the die.

An embodiment of the invention will now be described by way of example only, with reference to the accompanying diagrammatic drawing, the sole figure of which is a longitudinal sectional of the hammer according to the invention.

The high-speed anvilless hammer shown in the drawing comprises a bed 1 secured to a foundation (not shown). Mounted in guides 2 of the bed 1 and supported on resilient means 3 is a frame 4, the upper portion of which accommodates a power chamber 5 filled with a working fluid, for example an inert gas. Mounted in the power chamber 5 is a power cylinder 6, the latter being rigidly connected to the frame 4. The cylinder 6 accommodates an annular piston 7. By means of seals 8 and 20, the piston 7 separates the chamber 5 from a space 9 above the piston. A passage 10 connects the space 9 above the piston through a valve (not shown) to an external source of pressure fluid, preferably a liquid under pressure. The above-piston space 9 is bounded from above by an insert 26 so that the piston 7 is reciprocable within the annular space defined between the cylinder 6 and the insert 26.

The piston 7 includes a tubular piston rod 11 which has a central bore with a bushing 12 installed therein. The bushing 12 has, in cross section, a shape which prevents relative rotation between the piston rod and the bushing. A hammer head 13 has a working tool 14 attached to the bottom end thereof and is slidable within the bushing 12.

The hammer head 13 is held in an initial upper position by a hammer head retention mechanism 15 located within the insert 26.

The length of the bushing 12 is greater than the stroke of the hammer head 13.

Rigidly secured to the end of the piston rod 11 is a flange 16 provided with guiding surfaces 16a which may have the cross sectional shape of a prism, a circle, or an ellipse, for example. The flange extends 16 underneath the end face of the hammer head 13 for the purpose of retaining it before a blow and lifting it into the initial position after a blow. The guiding surfaces of the flange 16 mate with guides 17 of the frame 4.

The stroke H of the piston 7 exceeds the distance H, between the flange 16 and the die block 18 which comprises sectional dies 19 and is mounted in the lower portion of the frame 4. Alternatively the die block 18 may comprise solid dies. The stroke of the .hammer head 13 is less than the distance Hl.

Provided in the bottom portion of the frame 4 is a fluid cylinder 21 with a piston 22 and a piston rod 23. Passages 24 for supplying fluid (for example thin mineral oil) to the cylinder 21 are also provided in the bottom portion of the frame 4. The cylinder 22 serves to draw the dies 19 together and move them apart. The rod 23 of the piston 22 sealed relative to the frame 4 by the provision of seal 25.

The hammer operates as follows:- Liquid under pressure is delivered through passage 10 into the space 9 above the piston 7. The pressure of the liquid moves the piston 7 down together with the piston rod 11 and the flange 16. During the downward travel of the piston 7 the hammer head 13 is held in its initial upper position by the mechanism 15, and the working fluid in the chamber 5 becomes compressed.

When the piston 7 is in the lowermost position, the piston rod 11 presses, via the flange 16, against the die block 18 or a sheet blank (not shown). The interior of the piston rod 11 in conjunction with the die block 18 forms an enclosed zone within which deformation of the blank is subsequently effected.

Thereafter, the mechanism 15 is actuated to release the hammer head 13. The hammer head 13 disengages from the mechanism 15 and, under the action of the potential energy of the compressed working fluid contained in the chamber 5, strikes the blank situated in the die block 18. The liquid is forced from the space 9 through a valve (not shown) and the passage 10 by the pressure of the working fluid contained in the chamber 5. The piston 7, acting through the flange 16, returns the hammer head 13 together with the tool 14 into the initial position. The hammer head 13 with the tool 14 is held in the initial position by the mechanism 15 and also by the flange 16.

The deformed blank is removed from the die block 18 and thereafter the hammer is ready to strike again.

The high-speed anvilless hammer described is suitable for high-speed forming of parts from metals and alloys difficult to deform.

In the hammer described, the zone in which the blow imparted is isolated or enclosed by the tubular piston rod, whereby hammer operating noise is decreased considerably and the safety of hammer operation is improved.

The construction described permits the use of a hammer head having a small mass which enables a significant increase on the blank deformation rate and accurate control of Kinetic energy required for forming blanks.

The provision of a hammer head guide in the piston rod permits accurate positioning of the working tool in relation to the die block, which enhances the quality of stampings and prolongs the life of the tool.

Since the stroke of the piston exceeds the distance between the die block and the lower end of the piston rod, the piston rod is pressed against the die. The hammer can be used for stamping of sheet stock, for finishing working of metals and for forging blanks in sectional dies.

The hammer permits an increase in the extent of metal deformation, the depth of drawing stampings, and the working life of the dies.

WHAT WE CLAIM IS: 1. A high-speed anvilless hammer comprising a bed, guides provided on said bed, a frame supported on resilient means and mounted in said bed guides, a hammer head arranged to carry a working tool at its lower end, a die block mounted underneath

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

cylinder 6 accommodates an annular piston 7. By means of seals 8 and 20, the piston 7 separates the chamber 5 from a space 9 above the piston. A passage 10 connects the space 9 above the piston through a valve (not shown) to an external source of pressure fluid, preferably a liquid under pressure. The above-piston space 9 is bounded from above by an insert 26 so that the piston 7 is reciprocable within the annular space defined between the cylinder 6 and the insert 26.

The piston 7 includes a tubular piston rod

11 which has a central bore with a bushing

12 installed therein. The bushing 12 has, in cross section, a shape which prevents relative rotation between the piston rod and the bushing. A hammer head 13 has a working tool 14 attached to the bottom end thereof and is slidable within the bushing 12.

The hammer head 13 is held in an initial upper position by a hammer head retention mechanism 15 located within the insert 26.

The length of the bushing 12 is greater than the stroke of the hammer head 13.

Rigidly secured to the end of the piston rod 11 is a flange 16 provided with guiding surfaces 16a which may have the cross sectional shape of a prism, a circle, or an ellipse, for example. The flange extends 16 underneath the end face of the hammer head 13 for the purpose of retaining it before a blow and lifting it into the initial position after a blow. The guiding surfaces of the flange 16 mate with guides 17 of the frame 4.

The stroke H of the piston 7 exceeds the distance H, between the flange 16 and the die block 18 which comprises sectional dies

19 and is mounted in the lower portion of the frame 4. Alternatively the die block 18 may comprise solid dies. The stroke of the .hammer head 13 is less than the distance Hl.

Provided in the bottom portion of the frame 4 is a fluid cylinder 21 with a piston 22 and a piston rod 23. Passages 24 for supplying fluid (for example thin mineral oil) to the cylinder 21 are also provided in the bottom portion of the frame 4. The cylinder 22 serves to draw the dies 19 together and move them apart. The rod 23 of the piston 22 sealed relative to the frame

4 by the provision of seal 25.

The hammer operates as follows:- Liquid under pressure is delivered through passage 10 into the space 9 above the piston 7. The pressure of the liquid moves the piston 7 down together with the piston rod 11 and the flange 16. During the downward travel of the piston 7 the hammer head 13 is held in its initial upper position by the mechanism 15, and the working fluid in the chamber 5 becomes compressed.

When the piston 7 is in the lowermost position, the piston rod 11 presses, via the flange 16, against the die block 18 or a sheet blank (not shown). The interior of the piston rod 11 in conjunction with the die block 18 forms an enclosed zone within which deformation of the blank is subsequently effected.

Thereafter, the mechanism 15 is actuated to release the hammer head 13. The hammer head 13 disengages from the mechanism 15 and, under the action of the potential energy of the compressed working fluid contained in the chamber 5, strikes the blank situated in the die block 18. The liquid is forced from the space 9 through a valve (not shown) and the passage 10 by the pressure of the working fluid contained in the chamber 5. The piston 7, acting through the flange 16, returns the hammer head 13 together with the tool 14 into the initial position. The hammer head 13 with the tool 14 is held in the initial position by the mechanism 15 and also by the flange 16.

The deformed blank is removed from the die block 18 and thereafter the hammer is ready to strike again.

The high-speed anvilless hammer described is suitable for high-speed forming of parts from metals and alloys difficult to deform.

In the hammer described, the zone in which the blow imparted is isolated or enclosed by the tubular piston rod, whereby hammer operating noise is decreased considerably and the safety of hammer operation is improved.

The construction described permits the use of a hammer head having a small mass which enables a significant increase on the blank deformation rate and accurate control of Kinetic energy required for forming blanks.

The provision of a hammer head guide in the piston rod permits accurate positioning of the working tool in relation to the die block, which enhances the quality of stampings and prolongs the life of the tool.

Since the stroke of the piston exceeds the distance between the die block and the lower end of the piston rod, the piston rod is pressed against the die. The hammer can be used for stamping of sheet stock, for finishing working of metals and for forging blanks in sectional dies.

The hammer permits an increase in the extent of metal deformation, the depth of drawing stampings, and the working life of the dies.

WHAT WE CLAIM IS: 1. A high-speed anvilless hammer comprising a bed, guides provided on said bed, a frame supported on resilient means and mounted in said bed guides, a hammer head arranged to carry a working tool at its lower end, a die block mounted underneath

said working tool, a drive for driving the hammer head axially towards the die block, said drive comprising a power chamber arranged to contain a working fluid, and a cylinder with a piston including a piston rod, said cylinder being arranged for connection to a source of pressure fluid so that the piston can be moved to a lower position, said piston causing compression of the working fluid in the power chamber during such movement, the hammer head being mounted for reciprocating movement within a central bore of the piston rod and being subjected to a downwards force under the action of the pressure of the working fluid, a mechanism for releasably retaining the hammer head in an initial upper position during downwards movement of the piston, the stroke of said piston exceeding the distance between the die block and the lower end of said piston rod, whereby, when the piston is in a lowermost position, a closed zone is formed around said hammer head between said piston rod and the surface of said die block, in which zone deformation of a workpiece is effected by the working tool under the action of the compressed working fluid when the hammer head is released by the retaining mechanism, and means for returning the hammer head to its intitial upper position after its working stroke.
2. A hammer as claimed in claim 1, in which the hammer head is guided for reciprocating movement in the piston rod by means of a bushing mounted in the central bore of the piston rod, the length of the bushing exceeding the stroke of the hammer head.
3. A hammer as claimed in Claim 1 or Claim 2, in which the means for returning the hammer head to its initial position comprises a flange mounted on the end of the piston rod so as to extend underneath a lower end face of the hammer head, the flange being engagable with the lower end face of the hammer head to lift the hammer head upon upwards movement of the piston under the action of the compressed working fluid.
4. A hammer as claimed in Claim 3 further comprising means for axial rotation of the piston rod, said means comprising guiding elements provided on the frame and arranged to mate with guiding surfaces provided on the flange.
5. A high-speed anvilless hammer substantially as hereinbefore with reference to the accompanying drawings.