DYNAMIC BALANCING DEVICE FOR PRESS

Abstract: The present invention relates to a dynamic balancing device for a press. For avoiding the complexity of the structure of a prior art device of this kind, the structure thereof is changed such that a connecting rod is provided to fit in an eccentric member of a crankshaft, a link is provided to be journalled on one end thereof to a head of a larger diameter of said connecting rod, a pair of balance weights are provided on both ends of and close to the center of said crankshaft in a manner movable to substantially oppose to the direction of a slide of the press, a pair of levers is provided to be connected on one end thereof to each balance weight and to be journalled on an inter­ mediate point along the length thereof to a frame of the press, and the other end of each lever of the pair is journalled to the other end of said link.

Description: Detailed Description of the Invention: This invention relates to a dynamic balancing device for a press. In the prior art dynamic balance in inertia force is kept between a slide which moves up and down and a crank mechanism which rotates with eccentricity within a press by providing balance weights to move relative to the crankshaft or the slide via gears, levers or links. But this inevitably makes the whole structure complex and large, presenting a difficulty. An object of this invention is to obviate such defects of the prior art and to provide a dynamic balancing device for a press which is simple in construction and which can effectively use void spare within the frame of a press by connecting the upper end of a connecting rod which connects an eccentric member of a crankshaft and a slide with a balancing weight by links and levers. This invention will now be described referring to embodiments shown in drawings. FIG. 1 is a vertically sectioned frontal view of essential portions of a press for which an embodiment of this invention is applied. FIG. 2 is a sectional view cut at the line II-II of FIG. 1. FIG. 3 is a sectional view cut at the line III-III in FIG. 2. In FIG. 1, a crankshaft 2 is rotatably provided in a frame 1 of a press and eccentric members 3,3 are formed at two locations along the crankshaft 2. On one end of the crankshaft 2 is mounted a fly wheel 4 having a clutch. The rotation of the fly wheel 4 which is driven by a motor (not shown) is transmitted to the crankshaft 2 via the clutch. On the other end of the crankshaft 2 is provided a brake 5. Connecting rods 6,6, are engaged in a freely rotatable manner with the eccentric members 3,3 of the crankshaft 2 on one end having a large diameter while spherical members provided on the other ends of the connecting rods 6,6 are connected to a sliding member 7 of the press. The crankshaft 2 is provided with balancing weights 8,8 which keeps dynamic balance against the eccentric members 3,3. FIGs. 1, 2 and 3 show the structure of an embodiment of this invention wherein the head of a connecting rod of a larger diameter or the upper portion thereof is connected to a link 10 at the lower end thereof with a pin 9 parallel to the crankshaft 2. The upper end of a link 10 is forked into two. A pair of levers 13,13 are journaled on the upper portion of the frame 1 with a supporting axes 12,12 which are parallel to the crankshaft 2. The levers 13,13 are connected on one end thereof with the upper end of the link 10 with a pin 11. An eccentric bush 14 is interposed between the pin 11 and said one end of one of the levers 13 of said pair. This eccentric bush 14 is used to prevent the system comprising the links and levers which are connected by the pin 11 from being rocked. In FIGs. 2 and 3, if attention is focused on the movement of the pin 11, the locus of the pin 11 forms an arc determined by an arm of the left side lever 13 and the right side lever becomes interlocked to the left side lever by the function of the eccentric bush 14. Therefore, an eccentric bush 14 may be provided respectively on both levers 13,13. On the other end of each lever 13 is fixed respec­ tively pins 15,15 which are parallel to the supporting axes 12. A pair of balance weights 16,16 are provided on both forward and rearward sides (or lefthand and righthand sides in FIG. 2) of the crankshaft 2, the balancing weights being connected to pin 15 of the lever 13 on the upper end thereof. Each of the balance weights 16,16 is bored to have a hole 17 extending vertically, through which is engaged a guide pin 18 fixed upward on the frame 1 in a manner to allow up and down movement of the weight via a ball joint 19. The above described structure is provided for each connecting rod 6,6, of the pair. The operational effect will now be described. As the crankshaft 2 rotates, the slide 7 of the press is made to move vertically via the connecting rod 6. When the link 10 which is connected to the connecting rod 6 with a pin 9 moves up and down, the pin 11 moves in an arc around the supporting axis 12 of the lever 13 on the side the pin is directly connected. The other lever 13 connected via the eccentric bush 14 follows the pin 11 to smoothly swing as the center distance between the eccentric bush 14 and the supporting axis 12 changes by the revolving movement of the eccentric bush 14 in arc around the pin 11. As the levers 13,13 swing in this manner, the pin 15 swings in an arc around the supporting axis 12. The balance weight 16 connected to the pin 15 follows the movement of the pin 15 to move up and down with its head swinging forward and rearward of the press as it is connected to the guide pin 18 via the ball joint 19. As the pair of balance weights 16,16 swing symmetrically in respect of the plane including the shaft center of the crankshaft 2, no vibration in the horizontal direction is caused. As is obvious from the foregoing description, according to this invention, as balance weights are connected to the larger diameter head portions of connect­ ing rods via links and levers, the balancing structure becomes simplified and compact. Balance weights therefore may be provided to oppose to slides in the space within the frame of a press, thereby enabling effective use of the space. This invention can achieve practical effect and merits as above mentioned.

Claims: A dynamic balancing device for a press which is characterized in that a connecting rod is provided to fit in an eccentric member of a crankshaft, a link is provided to be journalled on one end thereof to a head of a larger diameter of said connecting rod, a pair of balance weights are provided on both ends of and close to the center of said crankshaft in a manner movable to substantially oppose to the direction of a slide of the press, a pair of levers is provided to be connected on one end thereof to each balance weight and to be journalled on an inter­ mediate point along the length thereof to a frame of the press, and the other end of each lever of the pair is journalled to the other end of said link.

Inventors: IMANISHI, SHOZO, SATO, MITSUO
Applicants: AIDA ENGINEERING LTD.
Application year: 1985
Main classification: B30B15
IPC codes: B30B15