US3842652A

US3842652A - Screw press

Info

Publication number: US3842652A
Application number: US00319683A
Authority: US
Inventors: T Yonezawa; T Inuki
Original assignee: Nippon Steel Corp
Current assignee: Nippon Steel Corp
Priority date: 1971-12-28
Filing date: 1972-12-29
Publication date: 1974-10-22
Anticipated expiration: 1991-10-22
Also published as: GB1359390A; DE2263857A1; DE2263857C3; IT973008B; DE2263857B2

Abstract

A screw press is provided comprising a frame, a saddle fixed relative to the frame and a slider element adapted to be driven into abutment with the saddle by operation of a screw shaft which is arranged to threadedly engage the frame and which has the slider element mounted at an end thereof. Rotation of the screw shaft to impart thereto a force driving the slider element into engagement with the saddle is effected by electric motor means which include a stator and a rotor, with the rotor being arranged as a flywheel of the press fixedly mounted upon the screw shaft. The stator is arranged to be fixed relative to the rotor and as the driving force imparted to the shaft during operation of the press causes the rotor to move in directions axially of the screw shaft, the stator is constrained to move therewith by slots formed in the frame which extend in directions parallel to the axis of the screw shaft.

Description

United States Patent [191 Yonezawa et al.

[ 51 Oct. 22, 1974 SCREW PRESS [75] Inventors: Toshiya Yonezawa; Tadahiko Inuki,

both of Kitayshu, Japan [73] Assignee: Nippon Steel Corporation, Tokyo,

Japan [22] Filed: Dec. 29, 1972 [21] Appl. No.: 319,683

[30] Foreign Application Priority Data Dec. 28, 1971 Japan 46-471280 Dec. 28, 1971 Japan 46-471281 Dec. 28, 1971 Japan 46-471279 52 us. Cl 72/454, 100/289, 310/96 [51] Int. Cl B2lj 9/18 [58] Field of Search 72/454; 100/289; 310/96 [56] References Cited UNITED STATES PATENTS 2,997,945 8/1961 Coton 100/289 3,418,860 12/1968 Hany 3,626,222 '12/1971 Dischler 310/96 FOREIGN PATENTS OR APPLICATIONS 1,300,829 8/[969 Germany 72/454 Primary Examiner--C. W. Lanham Assistant ExaminerGene P. Crosby Attorney, Agent, or Firm-Toren, McGeady and Stanger [57] ABSTRACT A screw press is provided comprising a frame, a saddle fixed relative to the frame and a slider element adapted to be driven into abutment with the saddle by operation of a screw shaft which is arranged to threadedly engage the frame and which has the slider element mounted at an end thereof. Rotation of the screw shaft to impart thereto a force driving the slider element into engagement with the saddle is effected by electric motor means which include a stator and a rotor, with the rotor being arranged as a flywheel of the press fixedly mounted upon the screw shaft. The stator is arranged to be fixed relative to the rotor and as the driving force imparted to the shaft during operation of the press causes the rotor to move in directions axially of the screw shaft, the stator is constrained to move therewith by slots formed in the frame which extend in directions parallel to the axis of the screw shaft.

5 Claims, 5 Drawing Figures iliih t: In:

SCREW PRESS The present invention relates to a screw press used in forming the material to be formed by forging.

As a forming equipment by forging the material to be formed, for example, a fluid-pressure press such as a hydraulic press is generally known. Also it is well known that a screw press is used as forming by forging can be done easily with simple structure with quite low production cost as compared to other types of presses.

In the drawings: FIG. l'is a view in front elevation of a conventional FIG. 2 is a view in front elevation of a first embodiment of the present invention with portions cut away and partially in section;

FIG. 3 is a plan view of the embodiment of FIG. 2 with portions cut away and partially in section;

FIG. 4 is a partial front elevation showing a modification of the embodiment of FIG. 2; and

FIG. 5 is a view in front elevation of another embodiment of the present invention.

An example of a conventionally known screw press will be explained referring to the drawings.

In FIG. 1, l is a machine frame, and a saddle 4 having a hammer part 3 is provided at the base portion of the machine frame 1. A slider element 5 also having a hammer part 3' is insertedly fitted with guide pieces 6 provided at the inner side of the machine frame 1 in a freely slidable manner. 7 is a flywheel insertedly attached to the upper end of a screw shaft 8 which is made to go through the upper part of the machine frame I, and the lower end of the screw shaft is insertedly positioned into the above-mentioned slider 5 in a freely rotatable manner. And the screw shaft 8 having male screw provided thereon is insertedly fitted with a female screw part 9 provided at the upper part of the machine frame 1 in a freely movable manner up and down (refer to FIG. 2). Friction disks 10 are insertedly fitted with a driving shaft 11 in such a manner as being positioned near the outer side plane of the abovementioned flywheel 7. A bearing 13 is provided at the upper part of a bracket 12 provided at the upper outside of the machine frame I, and supports the driving shaft 11 in a horizontal direction. A V-pulley 14 is insertedly attached to one end of the driving shaft 11, and a V-pulley 15 is insertedly fitted to the shaft of an electric motor, thus having V-shape belt 16 wound around them. A rotating direction change over lever 17 for the abovementioned flywheel 7, has its upper end insertedly positioned at the driving shaft 11, while its center part is held with a pin in place at a support piece 18 provided at the bracket 12 in a freely tilting manner.

When forming by forging is done by a screw press I composed as mentioned above, first an electric motor is started to rotate the friction, disk 10 insertedly fitted with the driving shaft 11. Next the lever 17 is operated to push the friction disk 10 for lowering the screw shaft against the flywheel, then the flywheel 7 is driven by the friction power between the friction disk 10 and the flywheel 7. Therefore, the screw shaft 8 connected to said flywheel is rotated by the rotating force of the flywheel 7 to lower the slider 5 provided at the lower end of the screw-shaft, thus the material to be formed placed on the saddle 4 is stricken. After striking, the change over lever 17 is quickly operated in a reverse direction to release the pressing of the friction disk 10, which is to lower the screw shaft, against the flywheel 7, then contrary to the time of lowering, the friction disk 10, which is to elevate the screw shaft, is pushed against the above-mentioned flywheel 7, making said flywheel 7 rotate in a direction reverse to that in lowering the screw shaft by friction, thus elevating the screw shaft 8.

As has been explained above in a conventional screw press large friction disks 10 are provided at the upper part of a press, and these friction disks are pushed against the flywheel of the press and rotated, to rotate the screw shaft which is connected to said flywheel by driving force through friction, then the material to be formed is forged with the mold provided at the lower part of the screw shaft by up and down movement of the screw shaft 8. Also in a conventional type screw press, the driving power transmitted to the flywheel through friction disks is determined by the coefficint of friction of friction material such as leather, etc., placed over the contacting plane of the flywheel and by the pushing power of the friction disk. Therefore in order to transmit large driving power, large pushing power and large coefficient of friction are required. However, as the pushing power becomes large, slip is caused because of the difference in speed between the friction disk and the flywheel at the time of acceleration, etc., and as great volume of heat is generated by this slip, there is a certain limit for said pushing power of the friction disk.

Further, since the acceleration, reduction and damping function of the flywheel are all determined by the pushing power of the friction disk and the change over control, etc. of the friction disk being pushed, very delicate adjustment is necessary, largely depending on skill by experience of an operator, thus there are such disadvantages that the workmanship in operation and handling largely affects the forge-forming operation and the maintenance of the press, etc. Also as has been explained in the description of the set-up, the fact that large friction disk is rotated at high speed over the screw press constitutes big fear and risk in operational safety.

Under thecircumstances, the present invention is intended to obtain a screw press in which the operation and control of the flywheel can be done automatically without depending on manual operation yet securing proper control, with quite safe equipment arrangement.

Now, examples of the present invention shall be explained in detail referring to'the drawings.

Example .1

- In FIG. 2 and FIG. 3, 1 is a machine frame, and a saddle 4 having a hammer part 3, is provided at the base part within the machine frame. A slider element 5 also having a hammer part 3 is insertedly fitted with guide pieces 6 provided at the inner side of the abovementioned machine frame 1 in a freely slidable manner. A flywheel 7 made of conductive metal is insertedly attached to the upper end of the screw shaft 8 which is made to go through the upper part of the machine frame. Further, the lower end of said screw shaft 8 is insertedly provided at the above-mentioned slider 5 in a freely rotatable manner.

The above-mentioned screw shaft 8 having male screw provided thereon is insertedly fitted with a female screw part 9 provided at the upper part of the machine frame 1 in a freely movable manner up and down. Linear motors l9 face against the side plane of the above-mentioned flywheel 7, and a plural number of the same are provided with certain gaps in a radial manner around the screw shaft 8. Said linear motors 19 are integrally provided with a support frame 20 which is insertedly fitted with the screw shaft 8 at the upper or lower portion of said flywheel 7 in such manner that said screw shaft is freely rotatable. A fixed frame 21 is provided at the upper part of the machine frame 1, and has guide grooves 22 facing against each of the support frames 20 to which said linear motors 19 are provided and also as having the forward end parts of the support frame 20 insertedly fitted therewith in a freely slidable manner. 23 is a checking piece such as screw cover.

Now, the function of the present invention having the above-mentioned set-up shall be explained in details. First when forming by forging is done, as the linear motors 19 are electrified, said linear motors l9 rotate the flywheel 7 to either right or left direction as shown by arrows in H6, 3. Therefore along with the rotating movement of said flywheel 7 the screw shaft 8 being connectedly provided with said flywheel will rotate integrally with the flywheel, and is for instance screwed downward. At this time the support frames 20 to which linear motors 19 are integrally provided descend along the guide grooves 22 of the fixed frames 21 corresponding to the descending of the screw shaft 8. Further the support frames 20 will, by the insertedly fitting with the guide grooves, hold the linear motors 19 at fixed positions without being rotated following the rotating action of the flywheel 7, also supporting such reaction as accompanying with the rotation of the flywheel 7. As mentioned above, the linear motors 19 will have up and down movements commonly made together with the flywheel 7 through the support frame 20, thereby the motors can always secure proper position against said flywheel thus insuring sure driving. Further, as the screw shaft 18 descends, the material to be formed placed on the hammer part 3 of the saddle 4 is stricken by the hammer part 3' of the slider provided at the lower end of the screw shaft 8.

The control of the screw shaft descending point is done by hitting a limit switch 24 provided at'the side part of the machine frame with a striker 25 provided at the slider 5. That is, as the striker 25 hits the limit switch 24, the phase with which current is supplied to the linear motors 19 is changed over giving rotating force in a reverse direction to the flywheel 7, thus elevating the flywheel 7 through the screw shaft 8. The upper limit of the slider 5 is detected by a limit switch 26, giving a braking force to the linear motors 19 to stop the mold at the predetermined position. By repeating the above-mentioned action continuous forging can be done.

FIG. 4 shows a modification of the above-mentioned example. Thatis the linear motors 19 are so provided as facing against the upper plane of the flywheel, and when the support frame to which linear motors 19 are integrally provided is provided under the flywheel 7, the linear motors 19 are naturally so provided as facing against under plane of the flywheel. As has been explained above, the present invention has such a set-up that linear motors are used as a driving means for the flywheel, and the linear motors are made to follow the up and down movement of the flywheel along the guide grooves of the fixed frame, and said linear motors are automatically controlled to provide smooth action of the acceleration, reduction and damping the flywheel. Therefore'the present invention does not call for man power as in the conventional equipment, thus delay in production, inadequate forming or troubles in driving system, etc. in forge-forming operation and equipment maintenance which accompany with manual operation can be eliminated, and at the same time fear in operation in safety can be removed, thus it has very great effectin improving productivity and safety.

Example 2 In FIG. 5, 201 is a machine frame, 204 is a saddle having a hammer part 203 being provided at the base part of said machine frame. 205 is a slider element also having a hammer part 203' and is insertedly fitted with guide pieces 206 provided at inner side of said machine frame 201 in a freely slidable manner. 207 is a flywheel made of conductive metal and is insertedly attached to a screw shaft 208 which is made to go through the upper part of the machine frame, and the lower end of said screw shaft 208 is insertedly provided at the abovementioned slider 205 in a freely rotatable manner. The thickness of the side plane of the flywheel 207 should have at least such value as equal to or more than the up and down movement distance of the screw shaft 208. The above-mentioned screw shaft 208 having male screw provided thereon is insertedly fitted with a female screw part 209 provided at the upper part of the machine frame in a freely movable manner up and down. 219 are linear motors and plural number of the same are provided with certain gaps facing against the side plane of the above-mentioned flywheel 207 in a radial manner around the screw shaft 208. 220 is a fixed frame provided at the upper part of the machine frame 1, and the above-mentioned linear motors 219 are fixedly provided at the fixed frame in such manner that the motors 219 are always positioned within the up and down movement range of the above-mentioned flywheel.

The function of the above example having such set up as mentioned above shall be explained in detail.

First when forge-forming is done, as the linear motors 219 are electrified, the linear motors 219 rotate the flywheel 207 either to right or left direction. Therefore, the screw shaft 208 connectedly provided with the flywheel 207 rotates integrally with the flywheel 207 along the rotating movement of the flywheel 207, thus screwed downward. As mentioned above even when the flywheel 207 is gradually descended the linear motors 219 are fixedly provided at the fixed frame 220 within the up and down movement range of the flywheel 207, therefore the motors are always facing against the side plane of the flywheel 207, thus the flywheel 207 can be continuously driven. Further, as the screw shaft 208 descends, the material to be formed placed on the hammer part 203 on the saddle 204 is stricken by the hammer part 203 of the slider 205 provided at the lower end of the screw shaft 208.

The control of the descending point of the screw shaft is done by hitting a limit switch 221 provided at the side of the machine frame with a striker 222 provided at the slider 205. That is, as the striker 222 hits the limit switch 221, the phase with which current is supplied to the linear motors 219 is changed over, giving rotating force to reverse direction to the flywheel 207 elevating the flywheel 207 through the screw shaft 208. The upper limit of the slider 205 is detected by another limit switch 223, giving braking froce to the linear motor 219 stopping the same at a predetermined position. By repeating the above-mentioned action continuous forging can be done.

As described above, in the present example such a flywheel is provided as having the thickness of side plane at least corresponding to the up and down movement distance of the screw shaft, and linear motors are provided at a fixed frame as a driving device for the flywheel in such a manner as being positioned within the range of up and down movement of the abovementioned flywheel, thereby said linear motors are made always to face against the flywheel regardless the up and down movement of the flywheel, and are automatically controlled, further the press has such arrangement and set up that the acceleration, reduction and damping function of the flywheel can be done smoothly, thereby same effect as in Example 1 can be obtained.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

We claim:

1. A screw press comprising, in combination, a frame, a saddle fixedly mounted relative to said frame, a slider element adapted to be driven into abutment with said saddle, a screw shaft rotatable about a fixed axis and having said slider element operatively connected thereto, said shaft being threadedly engaged upon said frame to impart a driving force to said slider element upon rotation of said shaft about said axis, electrical motor means including a stator and a rotor connected to produce a driving force for said press,

said rotor being arranged as a flywheel of said press and being fixedly mounted upon said screw shaft to rotate therewith, and means mounting said stator for movement relative to said frame in directions parallel to said axis but constraining said stator to prevent rotative movement thereof about said axis, whereby said stator and said rotor move together in a fixed relationship relative to each other in directions parallel to said axis during rotation of said shaft.

2. A press according to claim 1 wherein said mounting means comprise a support element having said stator fixedly mounted thereupon and extending between said screw shaft and said frame, means freely rotatively connecting said support element to said screw shaft but preventing relative axial motion therebetween, slot means formed in said frame extending parallel to said axis, and slot engaging means formed on said support element and arranged for sliding engagement with said slot means.

3. A press according to claim 1 wherein said rotor comprises a generally disc-shaped configuration having an outer peripheral surface and wherein said stator is located adjacent said peripheral surface and spaced radially therefrom to provide an interspacing clearance therebetween.

4. A press according to claim 1 wherein said rotor comprises a generally disc-shaped configuration having a planar surface arranged perpendicularly to said axis and extending radially therefrom, and wherein said stator is located adjacent said planar surface and spaced therefrom axially of said screw shaft to provide an interspacing clearance therebetween.

5. A press according to claim 1 wherein said stator comprises a plurality of segmental stator elements arranged symmetrically relative to said rotor about said axis.

Claims

1. A screw press comprising, in combination, a frame, a saddle fixedly mounted relative to said frame, a slider element adapted to be driven into abutment with said saddle, a screw shaft rotatable about a fixed axis and having said slider element operatively connected thereto, said shaft being threadedly engaged upon said frame to impart a driving force to said slider element upon rotation of said shaft about said axis, electrical motor means including a stator and a rotor connected to produce a driving force for said press, said rotor being arranged as a flywheel of said press and being fixedly mounted upon said screw shaft to rotate therewith, and means mounting said stator for movement relative to said frame in directions parallel to said axis but constraining said stator to prevent rotative movement thereof about said axis, whereby said stator and said rotor move together in a fixed relationship relative to each other in directions parallel to said axis during rotation of said shaft.