PRESS

Abstract: A press effectively reinforced for increasing precision in working and significantly reduced in noise during the operation thereof without requiring a special external device and extremely increasing the total weight thereof. It is provided with a reinforcing member (13, 14, 15, or 18) secured to a required place on each of side frames (10) composing either side of a frame (2) so as to restrict cut-open deformation of the frame (2) at the recessed part of a C-shaped side thereof.

Description: The invention relates to a press machine having a frame in C-shape in side elevational view, in which a bolster is mounted on a bed of a lower jaw portion of the frame, a slide and a driving system for driving the slide are mounted on an upper jaw portion thereof and at least one reinforcing member is fixedly secured to each side frames forming both sides of the frame at at least one predetermined place so as to suppress the deformation of flare of the opening of the frame. A press machine of this kind is known from the JP-Y2 62-13759. A prior art example of press machines of this kind is shown in Fig. 1. A frame 2 of the press machine 1 is C-shaped in side elevational view, and its lower jaw portion has a bed 4 supported thereon, whilst its upper jaw portion has a slide 5 and a driving unit for driving the slide 5 supported thereon. The arrangement is made such that when the slide 5 is lowered by rotation of a main spindle,a workpiece to be punched, not shown, on a lower die 7 mounted on a bolster 4a resting on the bed 4 is punched by an upper side (punch) 6 fixedly secured to the slide 5. In Fig. 1, reference numeral 3 denotes a front side plate of the frame, and 8 a side frame. In the above-mentioned prior art press machine, (1) to suppress or reduce the vibration of the frame or the level of noise generated by the press, a vibration damping material is mounted on the surface of the frame, for example, or (2) the whole press machine is surrounded by a box to isolate the noise. (Refer, for example, to "Examples of Measures for controlling Noise generated by Press Machines", collection of leactures and thesis on technique presentation conferences issued by Japanese Noise Control Engineering Society, P141, Sept., 1989) Further, as shown in Figs. 2 and 3, as a further alternative,(3) a piece of L-shaped reinforcing plate-shaped member 9 is mounted on the inner surface of each of side frames 8. Out of the prior arts, in case a vibration damping material is mounted on the surface of the frame as in the case (1), because of the need of using the material whose thickness is at least equal to or more than that of the frame, if the thickness of the frame is 22 mm, for example, then the total thickness of the frame and the vibration damping material becomes about 50 mm, thus causing an increase in the weight of the entire press machine, giving disadvantages in terms of cost and practicality. Further, in case the whole press machine is surrounded by a box as in the case (2), there were problems on press operation, cost and in terms of its occupying much working space in factories. Still further, in case of the alternative (3), because of the construction wherein a piece of plate-shaped member is fixedly secured to each of side frames 8 as the reinforcing member thereof, the reinforcing effect for preventing the opening formed between the upper and lower jaws of the frame from flaring was limited. Further, this prior art reinforcing member 9 is mounted on the side frame so as to extend upwards from the upper jaw portion, however, only a small loading is applied to this portion, and therefore its efficiency as a reinforcing member was low. The present invention has been made in view of the above-mentioned circumstances in the prior art, and for its principal object to provide a press machine which is effectively reinforced so as to improve the working accuracy of finished products without installing any special device on the outside thereof and without increasing extremely the weight of the entire press machine, and which is capable of reducing appreciably the level of noise generated by the machine in operation. To achieve the above mentioned object, the invention is characterized in that the reinforcing member has substantially the same shape as a substantially inverted trapezoidal through-hole formed in the rear, upper portion of each of said side frames and has the same thickness as the latter and is fixedly secured to the upper side surface of an upper jaw portion of each of the side frames. In a press machine 1 as shown in Fig. 1, when a slide 5 is lowered by rotation of a main spindle to allow an upper die (punch) 6 fixedly secured to the slide 5 to punch a workpiece to be punched, not shown, on a lower die 7 mounted on a bolster 4a resting on a bed 4, a frame 2 of the press machine 1 is subjected to a resistance to shearing of the workpiece so that a big magnitude of force is exerted on the frame 2, which tends to flare the opening formed between the upper and lower jaws of the frame. The workpiece is then cracked and broken suddenly. This breaking of the workpiece causes release of the loading therefrom, thus generating shock, which is propagated to the entire press machine, thereby generating noise and vibration. Further, when the force is exerted on the frame 2, which tends to flare the opening formed between the jaws thereof, a misalignment occurs between the upper die 6 and the lower die 7, thereby giving an adverse effect to the accuracy of finished products. Fig. 4 is a graph showing the relationship between punching load and noise (breakthrough noise). As shown by this graph, the lower the punching load, that is, the smaller the amount of deformation or flare of the opening of the frame 2 when the press machine is subjected to the resistance of shearing of the workpiece, the lower the level of noise becomes. In case of the C-shaped frame, the amount of deformation of notched portion of the upper jaw portion is the biggest. Consequently, if a reinforcing plate is fixedly secured to this upper jaw portion so as to eliminate the notched portion, then the above-mentioned amount of deformation or flare of the opening of the frame 2 is reduced, thus reducing the breakthrough noise. Further, as another means for reducing the level of the breakthrough noise, it is considered to remove noise generating portions. As a result of experiments, it was found out that the noise generated by the rear, upper portion of the side frames is 20 % of the noise generated by the entire press machine and this portion is the principal noise generating source. Therefore, the breakthrough noise is reduced by removing this portion. The foregoing reveals that if the amount of deformation or flare of the opening of the frame of the press machine is suppressed the noise level can be reduced, and the accuracy of finished products can be improved. The present invention has been made on the basis of this finding. According to the present invention, there is provided a press machine, characterized in that the reinforcing member has substantially the same shape as a substantially inverted trapezoidal through-hole formed in the rear, upper portion of each of the side frames and has the same thickness as the latter, and is fixedly secured to the upper side surface of an upper jaw portion of each of the side frames. Another reinforcing member may be an L-shaped plate member corresponding to the configuration of a zone which extends from the leading end of the lower jaw portion to the uppermost portion of the innermost upright wall of the recess, and at least two pieces of reinforcing members are superposed and fixedly secured to the zone on the inner surface of each of the side frames. Another reinforcing member may be a substantially rectangular plate member, and is fixedly secured by means of bolts or by plug welding to the inner surface of each of the side frames at a plurality of places. According to the present invention incorporating the above-mentioned aspects, the following advantage is obtained. The press machine is effectively reinforced so as to improve the working accuracy of finished products without the need for installing any special device on the outside thereof and without increasing extremely the weight of the entire press machine, and is capable of reducing appreciably the level of noise generated by the machine in operation. Stating in brief, since each of the side frames is reinforced by at least one plate member at at least one suitable place, the deformation of the frame or flare of the opening formed between the upper and lower jaws of the frame which tends to occur in operation is reduced, thereby reducing vibration, and hence, the noise caused thereby, and also improving working accuracy of finished products. The above-mentioned and other objects, aspects and advantages of the present invention will become apparent to those skilled in the art by making reference to the following description and the accompanying drawings in which preferred embodiments incorporating the principles of the present invention are shown by way of examples only. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic, overall perspective view showing a prior art press machine which is C-shaped in side sectional view; Fig. 2 is a schematic, side elevational view showing a prior art example of reinforcement of a side frame; Fig. 3 is a sectional view taken along line III - III in Fig. 2; Fig. 4 is a graph showing the relationship between the punching load and the noise; Figs. 5, 6 and 7 are schematic interior side elevational views showing first, second and third embodiments of the present invention; Fig. 8 is a sectional view taken along line VIII - VIII in Fig. 7; Figs. 9A nad 9B are plan views showing reinforcing members used in the embodiment shown in Fig. 7; Figs. 10 and 11 are schematic interior side elevational views showing a fourth embodiment of the present invention and its variant example; Figs. 12 and 13 are fragmentary sectional views showing two examples of reinforcing members for use in the embodiments shown in Figs. 10 and 11 which are fixedly secured to the side frames; and Fig. 14 is a graph showing the result of vibration damping experiments conducted in relation to the embodiments shown in Figs. 10 and 11. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Several embodiments of the present invention will now be described in detail below with reference to the accompanying drawings. (Figs. 5 to 14) First of all, the first embodiment of the present invention will be described with reference to Fig. 5. Further, in this embodiment, the same component parts as those of the prior art example shown in Fig. 1 are denoted by the same reference numerals, and the description thereof is omitted herein. Each of the left and right side frames 10 of a press machine 1 has a substantially inverted trapezoidal through-hole 11 formed in the rear, upper portion thereof. Further, each of the side frames 10 has a notched portion 12 formed above the upper jaw portion on the front side thereof. A piece of reinforcing plate 13 which is of a shape closing the side of the notched portion 12, for example, substantially inverted trapezoidal is fixedly secured by welding to the notched portion 12. As this reinforcing plate 13, the member which is cut out from the side plate 10 to form the through-hole 11 is used as it is. By dint of the above-mentioned construction, the area of the rear, upper portion of the side frame 10, which is a principal noise and vibration generating portion, is reduced, thereby reducing the noise and vibration generated in this portion. Further, the notched portion 12 formed above the upper jaw portion which is subjected to a high loading is reinforced by the reinforcing plate 13 so that the amount of flare of the opening formed between the upper and lower jaws of the side frames 10 is reduced by about 10 % as compared with the prior art example, thereby reducing the breakthrough noise. The second embodiment of the present invention will be described with reference to Fig. 6. A vertically extending reinforcing plate 14 comprised of a strip-shaped plate member is fixedly secured to each of the left and right side frames 10 forming both side walls of the frame of a press machine along the rear edge of the inner surface thereof. When the length, height and the thickness of the side frame 10 are denoted by L, H and T, the width W of the reinforcing plate 14 is 0.08L (W = 0.08L), and the thickness t of the plate 14 (which is the dimension of the plate 14 in a direction at right angles to the side frame 10) is 1.5T (t = 1.5T). Further, the height h₁ of the reinforcing plate 14 at the upper end thereof is 0.77H (h₁ = 0.77H), and the length h₂ of the plate 14 in the direction of the height thereof is 0.48H (h₂ = 0.48H). Stating an example of the above-mentioned dimensions, L = 1250 mm, T = 55 mm, H = 2210 mm, h 1 = 1702 mm, h 2 = 1061 mm. By dint of the above-mentioned construction, the deformation of the frame in the transverse direction was reduced by about 10 % as compared with the prior art example. Next, the third embodiment of the present invention will be described with reference to Figs. 7 to 9B. An L-shaped reinforcing member 15 is fixedly secured to the inner surface of each of the side frames 10 so as to extend from leading end of a lower jaw portion 10a of the C-shaped member to the top of a press operation zone 10b having a height ℓ which corresponds to the height of the innermost upright wall of the recess. This reinforcing member 15 is comprised of a first reinforcing member 16a and a second reinforcing member 16b which are superposed and fixedly secured in two layers. These reinforcing members 16a and 16b are formed as shown in Figs. 9A and 9B, respectively. When the height of the press operation zone of the side frame 10 is denoted by ℓ, the widths W₁ and W₂ of the reinforcing members 16a and 16b are as follows. W 1 = 1/2 ℓ, W 2 = 1/3 ℓ The ratio of the thickness t₁ of the reinforcing member 16a to the thickness t₂ of the reinforcing member 16b is as follows. t 1 : t 2 = 1 : 2.2 Stating one example of the actual dimensions of the reinforcing members 16a, 16b, ℓ = 450 mm, W₁ = 225 mm, W₂ = 150 mm, t₁ = 32 mm, and t₂ = 70 mm. In the above-mentioned construction, the frame is reinforced by the first and second reinforcing members 16a and 16b to withstand the loading exerted thereon, which tends to flare the frame. Further, the fourth embodiment of the present invention and the variant example thereof will be described with reference to Figs. 10 to 14. Figs. 10 and 11 each show only one of side frames. A substantially rectangular plate member 18 (or members 18) is (are) fixedly secured to the inner surface of the side frame 10 which is C-shaped in side view. There are two examples of arrangement of the plate member 18 (or members 18). In one example as shown in Fig. 10, a plurality of plate members 18 each having a small area are fixedly secured to the side frame at a plurality of places, whilst in another example as shown in Fig. 11 a single piece of plate member 18 having a large area is fixedly secured to the side frame 10 with the longer side thereof extending in the vertical direction. Further, a piece of plate member 18 whose thickness is about one-tenth of that of the side frame 10 or a plurality of separate plate members 18 are fixedly secured in a single layer to the side frame 10. Alternatively, a plurality of superposed plate members 18 each having the same thickness are fixedly secured in the form of one-piece or separate pieces to the side frame 10 as shown in Figs. 12 and 13. Further, in respect of fixing means, the superposed plate members 18 are fixedly secured by means of bolts 19 to the side frame 10 at a plurality of places as shown in Fig. 12, or they are fixedly secured by plug welding 20 to the side frame 10 at a plurality of places as shown in Fig. 13. It is adequate that the total area of the bolts 20 or the plug welded joints is about 5 to 6 % of the surface area of the plate member(s) 18. In the above-mentioned construction, when vibration is propagated to the side frame 10, the side frame 10 will vibrate together with the plate member 18 (or members 18) fixedly secured thereto. At that time, because both the side frame 10 and the plate member 18 (or members 18) have different natural frequencies and both the members 10 and 18 are fixedly secured at a plurality of places, and held only in contact with each other in the remaining portions, the above-mentioned vibration causes the members 10 and 18 to strike or chafe against each other in the contact portions. Such striking or chafing energy will give a vibration damping effect so that the above-mentioned vibration energy is absorbed, thereby suppressing the vibration. Experimental results on the degree of the above-mentioned damping of vibration are shown in Fig. 14. In this drawing, reference characters "a" indicate the result obtained in case only side frames 14 mm thick are provided, black dots indicate the result obtained in case plate members are fixedly secured by plug welding to each of side frames, white dots indicate the result obtained in case plate members are fixed by means of bolts to each of side frames, and X marks indicate the result obtained in case prior art vibration damping materials were used. As is apparent from this graph, the construction according to the present invention could provide nearly the same vibration damping effect as that obtained by the construction using the prior art vibration damping material. The foregoing description is merely illustrative of preferred embodiments of the present invention, and the scope of the present invention is not to be limited thereto. It will readily occur to those skilled in the art many changes and modifications of the present invention without departing from the scope of the present invention.

Claims: A press machine having a frame in C-shape in side elevational view, in which a bolster is mounted on a bed of a lower jaw portion of the frame (2), a slide and a driving system for driving the slide are mounted on an upper jaw portion thereof, and at least one reinforcing member (13) is fixedly secured to each side frames (10) forming both sides of the frame (2) at at least one predetermined place so as to suppress the deformation of flare of the opening of the frame (2), characterized in that the reinforcing member (13) has substantially the same shape as a substantially inverted trapezoidal through-hole (11) formed in the rear, upper portion of each of said side frames (10) and has the same thickness as the latter and is fixedly secured to the upper side surface of an upper jaw portion (10b) of each of the side frames. A press machine as claimed in claim 1, characterized in that another reinforcing member (15) is an L-shaped plate member corresponding to the configuration of a zone which extends from the leading end of the lower jaw portion to the uppermost portion of the innermost upright wall of the recess, and at least two pieces (16a,16b) of reinforcing members are superposed and fixedly secured to said zone on the inner surface of each of the side frames. A press machine as claimed in claim 1, characterized in that another reinforcing member (18) is a substantially rectangular plate member, and is fixedly secured by means of bolts (19) or by plug welding (20) to the inner surface of each of said side frames at a plurality of places. A press machine as claimed in claim 3, characterized in that said rectangular plate member is divided into a plurality of plate members (18) each having a small area.

Inventors: EJIMA KIKUO TECHNICAL INSTITUT, HONDA SHIGEKI TECHNICAL INSTIT, IMAMURA KAZUYA TECHNICAL INSTI, NISHIHARA YOSHITAKA AWAZU FACT, NISHIKAWA KENJI TECHNICAL INST, SAMEJIMA TAIRO TECHNICAL INSTI, SATO HIROHIDE AWAZU FACTORY OF, SUDA HIROYASU TECHNICAL INSTIT, SUZUKI KAZUHISA TECHNICAL INST, EJIMA, KIKUO, TECHNICAL INSTITUTE OF, HONDA, SHIGEKI, TECHNICAL INSTITUTE OF, IMAMURA, KAZUYA, TECHNICAL INSTITUTE OF, NISHIHARA, YOSHITAKA, AWAZU FACTORY OF K. K., NISHIKAWA, KENJI, TECHNICAL INSTITUTE OF, SAMEJIMA, TAIRO, TECHNICAL INSTITUTE OF, SATO, HIROHIDE, AWAZU FACTORY OF KABUSHIKI KAISHA, SUDA, HIROYASU, TECHNICAL INSTITUTE OF, SUZUKI, KAZUHISA, TECHNICAL INSTITUTE OF
Applicants: KOMATSU MFG CO LTD, KABUSHIKI KAISHA KOMATSU SEISAKUSHO
Application year: 1991
Main classification: B30B15
IPC codes: B30B15