A ball-type preform loading head

Abstract

The present invention discloses a ball-type preform loading head, which includes an inner core shaft with a screw hole provided on one end face, an outer core shaft coaxially sleeved on the inner core shaft, a ball guide sleeve, a wave spring, a lower ball ring, a tapered sleeve, a washer, a screw and balls; the ball guide sleeve is a stepped shaft and includes a main body with a central through hole, a first transition section, a diameter section and a second transition section, and the main body ends at the second transition section; a kinematic pair is formed between the inner peripheral surface of the central through hole and the outer peripheral surface of the inner core shaft; the side surface of the tapered sleeve is opposite to the second transition section; the part of the outer core shaft located on the side of the ball guide sleeve forms an upper ball ring opposite to the lower ball ring; the balls are located in the space surrounded by the tapered sleeve, the ball guide sleeve, the lower ball ring and the upper ball ring; the wave spring is sleeved on the ball guide sleeve between the two ball rings; the distance from the maximum protruding point of the ball exposed from the through hole to the outer surface of the ball ring is ≤ 0.75 mm. The present invention has the advantages of accurate and uniform loading.

Description

Technical Field

[0001] The present invention belongs to the technical field of blow molding machines, and particularly relates to a ball-type preform loading head. Background Art

[0002] The production process flow of beverage bottle blow molding generally includes five main steps: blank feeding after blank sorting → preform loading and heating → preform unloading into the mold → mechanical stretching and pre-blowing → blow molding. In the preform loading and heating process, the preform loading head is one of the important components for the smooth realization of the preform loading and heating process. Under the mechanical action of the outer core shaft rod and the inner core shaft rod, the preform is loaded onto the preform loading head and enters the heating furnace. When the preform passes through the heating area, it is heated to 90 - 115 degrees Celsius, unloaded after about 20 seconds of heating, and then sent into the blow molding cavity for blow molding.

[0003] The clamping methods of the loading head include outer clamping method and inner clamping method. For example, the outer clamping type loading head is adopted in the patent document CN203267195U, but it is basically not used in the industry at present. The inner clamping method is generally adopted in the industry at present. For example, the spring + elastic sheet type of the inner clamping method is disclosed in the patent document CN204123668U, and the O-ring + elastic sheet type of the inner clamping method is disclosed in the patent document CN208324180U, etc.

[0004] The loading head adopting the inner clamping method will have the following problems during operation:

[0005] 1) The problem of reduced elasticity and stiffness of the spring caused by long-term heating;

[0006] 2) The problem of rubber aging and shortened service life of the O-ring caused by long-term heating;

[0007] 3) The problem of uneven tension force acting on the movable elastic sheet by the spring or O-ring and poor coaxiality. Summary of the Invention

[0008] In order to solve the above existing problems, the present invention provides a ball-type preform loading head.

[0009] The ball-type preform loading head of the present invention includes an inner core shaft with a screw hole provided at one end face, an outer core shaft coaxially sleeved on the inner core shaft from top to bottom at the screw hole end, a ball guide sleeve, a wave spring, a lower ball ring, a tapered sleeve, a washer, a screw matching with the screw hole at the bottom of the washer, and balls;

[0010] The ball guide sleeve is a stepped shaft, including a main body with a central through hole, a first tapered transition section, a diameter section, and a second tapered transition section sequentially arranged on the main body, and the main body ends at the second tapered transition section; the inner peripheral surface of the central through hole and the outer peripheral surface of the inner core shaft form a kinematic pair in the up and down direction;

[0011] The tapered side surface of the tapered sleeve faces the second tapered transition section;

[0012] The inner ring surface of the lower ball ring forms an annular flat-bottomed groove along the circumferential direction. The two groove walls of the groove are formed as V-shaped inclined walls. The distance from the top of the upper inclined wall in the upward direction to the bottom of the groove is greater than the distance from the bottom of the lower inclined wall in the downward direction to the bottom of the groove. A protrusion is formed on the top of the upper inclined wall towards the ring central axis as a retaining ring, and a number of through holes for the balls to protrude out of the ring are uniformly arranged at the bottom of the groove;

[0013] An inner cylindrical groove for inserting the main body of the stepped shaft is coaxially provided on the inner side of the lower end of the outer core shaft with the inner core shaft. The outer side forms a positioning surface perpendicular to the axis. The middle part protrudes from the positioning surface to form an upper ball ring having the same structural shape as that of the lower ball ring after being turned over up and down. The top of the upper inclined wall of the upper ball ring faces the main body of the stepped shaft to form a tapered side surface in the same direction as the tapered side surface of the second tapered transition section, and serves as the tapered side surface of the outer core shaft;

[0014] The balls are located in the space surrounded by the tapered sleeve, the ball guide sleeve and the lower ball ring, and in the space surrounded by the tapered side surface of the outer core shaft, the ball guide sleeve and the upper ball ring;

[0015] The wave spring is located between the upper ball ring and the lower ball ring and is sleeved on the ball guide sleeve.

[0016] When the inner core shaft is axially pulled relative to the central through hole, the balls are clamped by the lower ball ring and the tapered sleeve, and the balls are clamped by the upper ball ring and the tapered side surface of the outer core shaft, and the balls protrude out of the ring; when the inner core shaft is axially lowered relative to the central through hole, the balls are clamped by the lower ball ring, the second tapered transition section and the tapered sleeve, and the balls are clamped by the upper ball ring, the first tapered transition section and the tapered side surface of the outer core shaft, and the balls are located inside the ring.

[0017] In order to effectively carry out tensioning, the distance from the maximum protruding point of the ball protruding from the through hole to the outer surface of the ball ring ≤ 0.75 mm.

[0018] Advantageous effects: The present invention adopts a ball-type tensioning method instead of the conventional spring + shim type and O-ring + shim type. The balls uniformly distributed in the upper and lower layers of ball rings directly contact the inner hole of the preform. The force on the inner hole of the preform is consistent and uniform. The coaxiality of the preform being clamped and the loading head is consistent, so that the tensioning degree of the loaded preform is fixed firmly. When the preform rotates, it is stable and will not tilt or shake, and the operations of loading and unloading the preform are accurate; by making the distance from the maximum protruding point of the ball protruding from the through hole to the outer surface of the ball ring ≤ 0.75 mm, effective tensioning can be carried out. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural view of the ball-type preform loading head according to an embodiment of the present invention;

[0020] Figure 2 For Figure 1 structural schematic diagram of the expansion of the ball-type preform loading head;

[0021] Figure 3 structural schematic diagram of the ball guide sleeve;

[0022] Figure 4 longitudinal sectional schematic diagram of the lower ball ring;

[0023] Figure 5 longitudinal sectional schematic diagram of the ball-type preform loading head according to the embodiment of the present invention;

[0024] Figure 6 schematic diagram of the loading head entering the preform when the inner core shaft and the outer core shaft descend simultaneously;

[0025] Figure 7 schematic diagram of the inner core shaft lifting and tightly clamping the preform;

[0026] Figure 8 schematic diagram of the inner core shaft descending to release the preform;

[0027] Figure 9 schematic diagram of the loading head disengaging from the preform after the inner core shaft and the outer core shaft are lifted simultaneously;

[0028] Figure 10 diagram of the position of the loading head in the preform plug component;

[0029] 1. Outer core shaft; 11. Cylindrical groove; 12. Positioning surface; 2. Inner core shaft; 3. Ball; 4. Ball guide sleeve; 41. Main body; 42. First tapered transition section; 43. Diameter section; 44. Second tapered transition section; 45. Central through hole; 5. Lower ball ring; 6. Cone sleeve; 7. Washer; 8. Screw; 9. Wave spring; 10. Upper ball ring. Detailed implementation manners

[0030] The technical solution of the present invention will be described in detail below through embodiments, but the protection scope of the present invention is not limited to the described embodiments. Embodiment

[0031] The present invention provides a ball-type preform loading head, which includes an inner core shaft 2 with a screw hole provided at one end surface, an outer core shaft 1 coaxially sleeved on the inner core shaft 2 from top to bottom at the screw hole end, a ball guide sleeve 4, a wave spring 9, a lower ball ring 5, a cone sleeve 6, a washer 7, a screw 8 located at the bottom of the washer 7 and mating with the screw hole, and a ball 3.

[0032] The ball guide sleeve 4 is a stepped shaft, including a main body 41 with a central through hole 45, a first conical transition section 42, a diameter section 43 and a second conical transition section 44 arranged in sequence on the main body 41, and the main body 41 ends at the second conical transition section 44; the inner circumference of the central through hole 45 and the outer circumference of the inner core shaft 2 form a moving pair in the up and down directions.

[0033] The conical side of the conical sleeve 6 is opposite to the second conical transition section 44. The inner ring surface of the lower pin ring 5 forms an annular flat-bottomed groove along the annular direction, and the two groove walls of the groove are formed into eight-shaped inclined walls. The distance from the top of the upper inclined wall in the upward direction to the groove bottom is greater than the distance from the bottom of the lower inclined wall in the downward direction to the groove bottom. A protrusion is formed at the top of the upper inclined wall toward the center line of the ring as a retaining ring for pin positioning, and a number of through holes for pins 3 to be exposed outside the ring are evenly arranged at the bottom of the groove. The inner side of the lower end of the outer core shaft 1 is coaxial with the inner core shaft 2 to form a cylindrical groove 11 for the stepped shaft body 41 to be inserted, and the outer side forms a positioning surface 12 perpendicular to the axis, and the middle part protrudes the positioning surface 12 to form an upper pin ring 10 with the same structural shape as the lower pin ring 5 after being turned upside down. The bottom end of the outer core shaft 1 forms a conical side in the same direction as the conical side of the second conical transition section 44 toward the stepped shaft body 41.

[0034] The pin 3 is located in a space surrounded by the cone sleeve 6, the pin guide sleeve 4 and the lower pin ring 5, and in a space surrounded by the cone side of the outer core shaft 1, the pin guide sleeve 4 and the upper pin ring 10. When the pin 3 is exposed from the through hole, the maximum protrusion point of the pin 3 is 0.75 mm away from the outer surface of the pin ring.

[0035] The wave spring 9 is located between the upper pin ring 10 and the lower pin ring 5 and is sleeved on the pin guide sleeve 4 .

[0036] All of the above components are made of stainless steel.

[0037] In the actual process of loading a preform with a bottle mouth diameter of 20.25 mm, first, the outer core shaft 1 is put on the inner core shaft 2, and the pins 3 are installed on the upper pin ring 10 included in the outer core shaft 1, and then the pin guide sleeve 4 is put on, and the wave spring 9 is put on the pin guide sleeve 4, and then the upper and lower pin rings 5 ​​are put on the inner core shaft 2, and after the pins 3 are installed, the cone sleeve 6 is put on, and then the washer 7 is placed on the bottom of the cone sleeve 6, and the screw 7 is inserted into the screw hole of the inner core shaft 2 to tighten, and then the pin type preform loading head is obtained. The inner core shaft 2 of the loading head can be lifted and lowered relative to the pin guide sleeve 4, but cannot rotate. The specific number of pins 3 loaded is determined according to the bottle mouth size and the pin diameter, and the loading head with different numbers of pin ring through holes is selected for use. In this embodiment, 7 pins are loaded.

[0038] Then the preform loading starts. Under the action of an external mechanism (cam), the outer mandrel 1 (including the upper ball ring 10) and the inner mandrel 2 descend and insert into the preform. When the lower positioning surface 12 of the outer mandrel 1 (including the upper ball ring 10) contacts the upper end surface of the inner diameter of the preform mouth, the descent stops at the set stroke to achieve axial and radial positioning. Then the inner mandrel 2 starts to lift under the action of the external cam, driving the ball guide sleeve 4 and the tapered sleeve 6 to lift upward to the set height. During the lifting process, the inclined surface of the upper half of the ball guide sleeve 4 pushes the balls 3 in the upper ball ring 10 radially outward, and the balls 3 contact the inner hole of the preform to achieve tightening. The balls 3 in the lower ball ring 5 are pushed radially outward by the tapered sleeve 6, and the balls 3 contact the inner hole of the preform to achieve tightening. Thus, the loading of the preform is completed.

[0039] The initial state of preform unloading is the preform loading state of the previous step. When starting to unload, the inner mandrel 2 starts to descend to the set stroke under the action of the external cam. During the descent of the inner mandrel 2, it drives the ball guide sleeve 4 and the tapered sleeve 6 to move downward, and the balls 3 in the upper and lower layers of ball rings retract radially inward, and the balls 3 are disengaged from contact with the inner hole surface of the preform. Then the inner mandrel 2 and the outer mandrel 1 (including the upper ball ring 10) are lifted simultaneously to disengage from the preform, achieving the unloading of the preform.

[0040] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as a limitation of the present invention itself. Various changes in form and detail may be made without departing from the spirit and scope of the present invention defined by the appended claims.

Claims

1. A ball-type preform loading head, characterized in that, It includes an inner core shaft with a screw hole provided at one end face, an outer core shaft coaxially sleeved on the inner core shaft from top to bottom at the screw hole end, a ball guide sleeve, a wave spring, a lower ball ring, a tapered sleeve, a washer, a screw matching with the screw hole at the bottom of the washer, and balls; The ball guide sleeve is a stepped shaft, including a main body with a central through hole, a first tapered transition section, a diameter section, and a second tapered transition section sequentially arranged on the main body, and the main body ends at the second tapered transition section; a kinematic pair in the up and down direction is formed between the inner peripheral surface of the central through hole and the outer peripheral surface of the inner core shaft; The tapered side of the tapered sleeve faces the second tapered transition section; The inner ring surface of the lower ball ring forms an annular flat-bottomed groove along the circumferential direction, and the two groove walls of the groove are formed as octagonal inclined walls. The distance from the top of the upper inclined wall in the upward direction to the groove bottom is greater than the distance from the bottom of the lower inclined wall in the downward direction to the groove bottom. A protrusion is formed as a retaining ring towards the ring central axis at the top of the upper inclined wall, and a number of through holes for the balls to protrude out of the ring are uniformly arranged at the groove bottom; A cylindrical groove for inserting the main body of the stepped shaft is coaxially provided in the inner side part at the lower end of the outer core shaft and the inner core shaft, a positioning surface perpendicular to the axis is formed on the outer side part, and an upper ball ring with the same structural shape as the structure of the lower ball ring after being turned over up and down is formed by the middle part protruding from the positioning surface. The bottom end of the outer core shaft forms a tapered side facing the tapered side of the second tapered transition section towards the main body of the stepped shaft; The balls are located in the space surrounded by the tapered sleeve, the ball guide sleeve, and the lower ball ring, and in the space surrounded by the tapered side of the outer core shaft, the ball guide sleeve, and the upper ball ring; The wave spring is located between the upper ball ring and the lower ball ring and is sleeved on the ball guide sleeve; The above components are all made of stainless steel.

2. The ball-type preform loading head according to claim 1, characterized in that, The distance from the maximum protruding point of the ball protruding from the through hole to the outer surface of the ball ring ≤ 0.75 mm.

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