Patent Publication Number: US-3874210-A

Title: Apparatus for producing a corrugated leaf spring

Description:
4 ilnrted States tent 11 1 1111 3,874,210 Hayashi et a1. 1 1 Apr. 1, 1975 [54] APPARATUS FOR PRODUCING A 464,403 12/1891 Turpin 72/168 CO G LEAF SPRING 483,192 9/1892 White 72/168 I 1,015,429 1/1912 Fahrney 72/196 [751 Inventors: Jumchl Hayashl, Akl; Tatiakl 1,617,069 2/1927 McLaughlin 72/196 Kobayashi, Hiroshima, both of 2,963,048 12/1960 Smith 140/ 105 Ja an 3,712,101 1/1973 Bemrose et a1. 72/465 [73} Assignee: T0y0 Kogyo Co., Ltd.,  
  Hiroshima, Japan Primary E.ranziner-Lowell A. Larson Filed: Dec. 1973 Attorney, Agent, or FzrmFleit &amp; Jackson [21] Appl. No.: 421,763  
 [57] ABSTRACT 1 1 Foreign Application Priority ata Apparatus for producing a corrugated leaf spring hav- Dec. 8, 1972 Japan 47-123799 ing a sideward curvature. Said apparatus includes a pair of intermeshing bevel gears each carrying a bev- [52] US. Cl 72/168, 72/196, 72/465 eled forming roller. The beveled forming rollers have [51] Int. Cl 821d 13/04 complementarily shaped waved contours between [58] Field of Search 72/167, 168, 196, 465; which a spring blank is introduced. One of the rollers 140/105 is mounted on the associated bevel gear through resilient means so as to accommodate any variation in [56] References Cited thickness of the blank.  
  UNITED STATES PATENTS 237,610 2/1881 Scherb 72/465 4 Clams 4 Drawmg F&#39;gures APPARATUS FOR PRODUCING A CORRUGATED LEAF SPRING The present invention relates to an apparatus for producing a corrugated leaf spring having a widthwise curvature. More particularly, the present invention relates to an apparatus for producing such a leaf spring by means of a pair of beveled forming rollers.  
  In a rotary piston type engine having a substantially triangular rotor disposed for rotation in a trochoidal cavity defined in a casing, curved side seals are disposed between the side surfaces of the rotor and the adjacent inner surfaces of the casing substantially along the curvature of the rotor periphery. For this purpose, the rotor is provided in the side surfaces with annular grooves for receiving such side seals. In order to force the side seals into sealing contact with the adjacent surfaces of the casing, corrugated leaf springs are disposed behind the seals.  
  Hithertofore, such a corrugated leaf spring has been produced through separate steps of providing widthwise curvature in a spring blank and thereafter providing a waved or corrugated form therein. The wave forming or corrugating process has been accomplished by pressing operation which requires expensive preformed punch and die. In the wave forming process using the pressing operation, non-uniform residual stress distribution is produced and an increased labour is required for eliminating deformations which appear after heat treatment due to the existence of the nonuniform stress distribution.  
  The present invention has an object to provide an apparatus which can eliminate the aforementioned problems of prior art.  
  A further object of the present invention is to provide an apparatus which can provide widthwise curvature and corrugation through one step.  
  According to the present invention, there is provided an apparatus for producing a corrugated leaf spring having a widthwise curvature, said apparatus comprising a pair of co-operating bevel gears, and a pair beveled forming rollers having complementarily shaped waved contours and co-operating with each other to form a nip therebetween, one of said forming rollers being secured to one of said bevel gears and the other of said forming rollers being mounted on the other of said bevel gears through yieldable means. A guide means may be provided for guiding a spring blank into the nip of the forming rollers. Preferably, said other forming roller is mounted on said other bevel gear through spherical bearing means so that the roller can be inclined with respect to the bevel gear, and resilient means is provided between the bevel gear and the forming roller so that the roller is held perpendicularly to the axis of the bevel gear.  
  The above and other objects and features of the invention will become apparent from the following descriptions of embodiments of the invention taking reference to the accompanying drawings, in which:  
  FIG. 1 is a perspective view of the apparatus in accordance with one embodiment of the present invention;  
  FIG. 2 is a sectional view of the apparatus shown in FIG. 1;  
  FIG. 3 is a sectional view showing another embodiment of the present invention; and  
  FIG. 4 is a perspective view of a corrugated leaf spring produced by the apparatus of the present invention.  
  Referring to the drawings, particularly to FIGS. 1 and 2, the apparatus shown therein includes a pair of rotating units 1 and 2 which include rotatable shafts 3 and 4, respectively. The rotating unit 1 has a bevel gear 5 and a beveled forming roller 6. The bevel gear 5 is secured to the shaft 3 through a key 3a or other suitable means, while the forming roller 6 is mounted on the shaft 3 through spherical bearing means 8 and 9 for inclination within a limited angle with respect to the shaft 3. Between the bevel gear 5 and the forming roller 6, there are disposed resilient springs 7 for maintaining the roller perpendicularly to the axis of the shaft 3.  
  The rotating unit 2 has a bevel gear 10 secured to the shaft 4 by a key 4a or other suitable means. A beveled forming roller 12 is secured to the bevel gear 10 by means of bolts 19 with the intervention of a restraining element 11 and shims 18. Another restraining element 13 is secured to the forming roller 12 at the side opposite to the element 11. As shown in FIGS. 1 and 2, the bevel gears 5 and 10 mesh with each other, and the forming rollers 6 and 12 have complementarily formed waved contours as shown by 14, 15, 16 and 17. A guide member 21 is provided for guiding a spring blank A to the nip of the forming rollers 6 and 12. The restraining elements 11 and 13 have-peripheral portions extending into the opposite sides of the nip of the forming rollers 6 and 12 so as to restrain the spring blank A from escaping sidewardly from the nip.  
  In operation, one of the shafts 3 and 4 are driven in the direction shown by arrow and a spring blank A is introduced through the guide member 22 into the nip of the beveled forming rollers 6 and 12. As the blank A is passed through the nip, it is applied with a widthwise curvature and at the same time with a corrugated form. Thus, a spring as shown in FIG. 4 is obtained.  
  The spherical bearing means 8 and 9 and the resilient springs 7 allows the forming roller 6 to incline when the thickness of the blank A varies so as to accommodate any variation in thickness of the blank A. Thus, it is possible to prevent the forming stress from increasing beyond an allowable level.  
  FIG. 3 shows another embodiment of the present invention. In this embodiment, the rotating unit 1 has a leaf spring 20 secured to the shaft 3, and a beveled forming roller 6 is secured to the leaf spring 20.  
  The invention has thus been shown and described with reference to specific embodiments, however, it should be noted that the invention is not limited to the structural details of the illustrated embodiments but changes and modifications may be made without departing from the scope of the appended claims.  
 We claim:  
  1. An apparatus for producing a corrugated leaf spring having a widthwise cu.rvature, said apparatus comprising: first and second cooperatmg bevel gears; first and second beveled forming rollers mounted on the respective first and second bevel gears, said first and second forming rollers serving to shape said corrugated leaf spring, having waved contours, and cooperating with each other to form a nip therebetween; means for securely mounting said first forming rolleron said first bevel gear; and yieldable means for mounting said second forming roller on said second bevel gear.  
 said second forming roller is secured to said second bevel gear through leaf spring means.  
  4. An apparatus in accordance with claim 1 in which means is provided for preventing a spring blank from being displaced sidewardly from the nip of the forming