Metal deforming – With means to drive tool – Including screw-actuated tool support
Patent
1988-01-28
1989-11-21
Jones, David
Metal deforming
With means to drive tool
Including screw-actuated tool support
72466, 83631, 100289, B21D 2200, B21J 910
Patent
active
048813990
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to mechanical engineering and more specifically to a double-action screw press.
The present invention may be most efficiently used in press-forging and particularly in closed-die forging.
The present invention may be used advantageously for producing precision parts of a complicated configuration from ordinary and difficult-to-form metals and alloys for gear pumps, gears, couplings, stepped shafts, T-pieces, cross-pieces, gas-turbine engines, fuel feed control equipment, etc.
Parts are conventionally worked by using a method of closed-die forging in which cylindrical blanks are deformed in one stroke. In using double-action screw presses for closed-die forging, an elastic collision of the dies takes place when the outer slide approaches the extreme bottom position, due to which the outer slide together with the top die rebounds upwards, thereby causing an opening of the joint between the dies. At the moment when the outer slide rebounds, the inner slide with the press tool secured thereon starts to move downwards at an increased speed and deforms the blank with the joint between the dies open. This leads to splashing of the metal out of the dies and, as a rule, results in spoilage.
PRIOR ART
Attempts to solve the problem associated with braking the outer slide when it approaches the extreme bottom position, i.e. to reduce the speed of the outer slide so that the moment the press tool dies start to close, this speed equals or is close to zero, resulted in the development of a double-action screw press according to USSR Inventor's Certificate No. 854,470, cl. B30B 1/18 published in the Bulletin "Discoveries, Inventions, Industrial Designs, Trade Marks" No. 30, 1981.
The known screw press comprises a frame with guideways and a first screw installed for rotation along the longitudinal axis of the frame. One end of the screw is kinematically associated with slides and the other end thereof is rigidly coupled with a flywheel rotated by any known drive. Disposed in the guideways coaxially with the first screw is an outer slide incorporating two intercommunicated spaces. One of them, the lower space that faces the press tool, accommodates an inner slide while the other space houses a carrying element which is essentially a nut body in engagement with the first screw. The nut body is rigidly coupled with a hollow screw in the inner space of which the first screw is freely disposed. The hollow screw is in engagement with a nut rigidly coupled with the inner slide.
The known press is provided with a mechanism for braking the outer slide when it approaches the extreme bottom position. This mechanism comprises a traverse installed for movement along the longitudinal axis of the press in the guideways secured on the press frame, and at least two elastic elements rigidly installed on the frame above the outer slide when it is in the extreme top position. A threaded hole is made in the traverse. On the side facing the flywheel, the nut body is provided with a thread opposite in direction relative to the thread of the screw. The threaded portion of the nut body is in engagement with the threaded hole in the traverse.
When the outer slide approaches the extreme bottom position the nut body moves the traverse along its guideways. The traverse interacts with the elastic elements.
The double-action screw press of the known design has a low efficiency because of the energy losses in overcoming the frictional forces arising in the nut body-to-traverse threaded joint when the outer slide approaches the extreme bottom position, as the inner slide moves for accomplishing the process of deformation and as the inner slide returns into the initial position relative to the outer slide.
A rise of the energy losses in the threaded joint is explained by the fact that the joint has a constant and large area of contact between the nut body and the traverse which leads to an increase in the resisting moment to rotation of the nut body in the traverse.
In addition, the provision of the thread
REFERENCES:
patent: 4590787 (1986-05-01), Trimborn
Bocharov Jury A.
Bovykin Igor V.
Lunkov Evgeny S.
Myakinenkov Vladimir I.
Nosov Anatoly P.
Experimentalny nauchno-issledovatelsky institut kuznechno-presso
Jones David
Moskovskoe Vyschee tekhnicheskoe uchilische imeni N.E.Baumana
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