JP2013180786A - Pump cylinder for liquid ejector and liquid ejector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pump cylinder, which contributes to a reduction in weight while having a required strength by providing a plurality of rigid ribs on a thin body part.SOLUTION: A pump cylinder has a large-diameter cylindrical head part 4 having a collar 6 formed on the periphery thereof, a middle-diameter cylindrical body part 10 extended downward from the lower end of the head part 4, a small-diameter cylindrical leg cylinder part 18 extended from an inward flange 16 attached to the inner surface lower end of the body part 10, and a ventilation hole 11 formed at an upper part of the body part 10. The cylindrical wall of the body part 10 is formed with a small thickness, compared with the head part 4, and a plurality of rigid ribs 12 having an equal height are vertically provided at equal intervals on the whole outer circumferential surface of the body part 10 to extend substantially over the vertical length of the body part 10.

Description

  The present invention relates to a pump cylinder for a liquid ejector and a liquid ejector incorporating the pump cylinder.

  This type of pump cylinder has a large-diameter cylindrical head with a collar around it, and a medium-diameter cylindrical body is attached to the lower end of the inner surface of the body from the lower end of the head. It is known that a small-diameter cylindrical leg tube portion is suspended from the inward flange and is formed with a substantially uniform wall thickness as a whole (Patent Document 1).

JP 2003-95361 A

  When the pump cylinder is simply made thinner and lighter for the purpose of reducing the weight of the conventional liquid ejector, the pump cylinder body swells outward due to a decrease in strength, or it slides up and down due to sliding with the piston. There was a possibility of causing deformation. If it does so, it may have a bad influence on the seal location of the internal peripheral surface of the trunk | drum of a pump cylinder, and the operating member of a liquid ejector, and the stroke of an operating member, and a function may be impaired.

  There is a method of adding a rigid rib as a method of reinforcing the pump cylinder. However, if a size and number more than necessary are added, the object of weight reduction cannot be achieved. Depending on the size of the ribs, sink marks may be generated, which adversely affects the function.

A first object of the present invention is to provide a structure of a pump cylinder that has a required strength and contributes to weight reduction by attaching a plurality of rigid ribs to a thin body portion.
The second object of the present invention is to adjust the size of the rigid rib so as not to cause sink marks on the inner peripheral surface of the body of the pump cylinder.
The third object of the present invention is to provide a liquid ejector that is reduced in weight by employing the pump cylinder.

The first means has a large-diameter cylindrical head 4 having a collar 6 around it. From the lower end of the head 4, the medium-diameter cylindrical trunk 10 and the trunk 10 In the pump cylinder which has a small diameter cylindrical leg tube part 18 suspended from an inward flange 16 attached to the lower end of the inner surface, and has a vent hole 11 in the upper part of the body part 10,
The cylindrical wall of the body part 10 is formed thinner than the head part 4, and a plurality of equal-sized rigid ribs 12 are provided over the entire outer peripheral surface of the body part 10 over almost the entire vertical length of the body part 10. Vertically set at intervals,
The height h at which the rigid rib 12 protrudes in the radial direction of the body portion 10 is made smaller than the circumferential distance r _α between the rigid ribs 12,
In addition, the circumferential width t _L of the rigid rib 12 is set to be equal to or less than half the radial thickness t ₁ of the cylindrical wall of the body portion 10.

  This means proposes that the body portion 10 of the pump cylinder 2 shown in FIG. 1 is thinner than the head portion 4, and that a plurality of vertical rigid ribs 12 are provided on the entire outer peripheral surface of the body portion 10. Since the body portion 10 is a portion where a later-described operating member 40 urged by a spring comes into sliding contact, if the strength is insufficient, the body portion 10 may be stretched and deformed by the spring force. Therefore, the longitudinal deformation ribs 12 are countered against the extension deformation by the longitudinal rigid ribs 12 arranged at equal intervals as shown in FIG.

Further, in this means, the relationship between the height h of the rigid rib 12 and the distance r _α between the rigid ribs 12 is expressed by Formula 1, and the width t _L of the rigid rib 12 and the body portion 10 other than the rigid rib forming portion. It is proposed that the relationship with the thickness t _{1 of the above} is expressed by Formula 2. If the height h of the rigid rib 12 is equal to or greater than the distance between the rigid ribs, it is difficult to contribute to the weight reduction of the pump cylinder 2, and the width t _L of the rigid rib 12 is This is because if the thickness exceeds half, the risk of sink marks in the body 10 increases.
[Formula 1] h <r _α
[Equation _{2] t L ≦ t 1/} 2

The second means is a liquid ejector,
A pump cylinder 2 for a liquid ejector as a first means, an operating member 40 having a cylindrical piston that can move up and down the inner surface of the body 10 of the pump cylinder 2, and a lower half of the operating member 40 And a spring 52 interposed between the lower part of the pump cylinder 2.

  As shown in FIG. 4, this means proposes a liquid ejector incorporating the pump cylinder 2 described above.

According to the invention relating to the first means, since the plurality of rigid ribs 12 are provided vertically on the body 10 of the pump cylinder, the body 10 can be slimmed (thinned) without reducing the strength of the pump cylinder 2.
According to the invention according to the first aspect, it is so arranged smaller than the distance r _alpha rigid rib 12 between the height h of the rigid ribs 12, which contributes to weight reduction.
Further, according to the invention relating to the first means, since the circumferential width t _L of the rigid rib 12 is set to be equal to or less than half the radial thickness t ₁ of the cylindrical wall of the body portion 10, sink marks are generated on the inner peripheral surface. This can reduce the risk of occurrence.
According to the invention relating to the second means, since the pump cylinder of the first means is employed, a lightweight liquid ejector can be provided without impairing functionality.

It is a half sectional view of a pump cylinder for liquid ejectors concerning an embodiment of the present invention. It is a bottom view of the pump cylinder of FIG. It is a cross-sectional view of the principal part of the pump cylinder of FIG. It is a longitudinal cross-sectional view of the liquid ejector containing the pump cylinder of FIG. FIG. 2 is an explanatory diagram of a design method of the pump cylinder of FIG. 1, in which FIG. 1A is a transverse section of the pump cylinder, and FIG. 1B is a partially enlarged view of the transverse section. FIGS. 6A and 6B are explanatory diagrams of a pump cylinder that is in proportion to FIG. 5, in which FIG. 5A is a transverse cross section of the pump cylinder, and FIG. It is a half sectional view of a pump cylinder which is a reference example of the present invention. It is a half sectional view of a conventional pump cylinder. It is a cross-sectional view of a conventional pump cylinder.

  A liquid ejector including a pump cylinder 2 according to an embodiment of the present invention will be described with reference to FIGS. For the convenience of explanation, explanation will be given starting from a conventionally known part.

  As shown in FIG. 4, the liquid ejector includes a pump cylinder 2, a mounting member 20, a retaining member 26, a valve mechanism 36, an operating member 40, and a spring 52. Each of these members can be formed of a synthetic resin unless otherwise specified.

  The pump cylinder 2 includes a large-diameter cylindrical head 4, a medium-diameter cylindrical body 10, and a small-diameter cylindrical leg cylinder 18.

  The head 4 has a flange 6 protruding from the outer peripheral surface of the lower half 4a, and a retaining protrusion 8 is provided around the outer peripheral surface of the upper half 4b. A packing 7 is attached to the lower surface of the flange 6.

  The trunk portion 10 hangs down downward from the lower end portion of the head 4. A vent hole 11 is opened at the upper portion of the body portion 10, and an inward flange 16 that also serves as a valve seat is attached to the lower end of the inner peripheral surface of the body portion 10. An annular raised portion is provided on the inner peripheral portion of the upper surface of the inward flange 16.

  The leg tube portion 18 hangs from the inner peripheral portion of the lower surface of the inward flange 16. The leg tube portion 18 is a tube portion for fitting the suction pipe P.

  The mounting member 20 is a member for mounting the pump cylinder 2 on the mouth and neck of a container body (not shown). The mounting member 20 protrudes inwardly from the upper end of the mounting cylinder 22 for screwing onto the outer surface of the mouth-and-neck portion, and projects from the top of the flange-shaped top wall 23 to the upper end surface of the mouth-and-neck portion. Are provided so that the flange 6 and the packing 7 of the pump cylinder 2 can be clamped.

  The retaining member 26 is fitted from the inner peripheral portion of the lower surface of the ring-shaped top wall 28 to the double cylindrical retaining cylindrical portion 30 and from the outer peripheral portion of the lower surface to the outer cylindrical portion 32 from the lower surface portion between them. The combined tube portions 34 are respectively suspended. The fitting cylinder 34 is fitted on the outer surface of the upper half 4b of the head 4 of the pump cylinder 2. Further, the retaining cylinder part 30 is inserted into the pump cylinder 2.

  The valve mechanism 36 is a cylindrical body having a top shape and a lower end having a large diameter, and is attached in the lower part of the body portion 10 of the pump cylinder 2. A valve plate is attached to the inner surface of the lower end portion of the cylinder so as to be movable up and down, and a suction valve 38 is formed by the valve plate and the inward flange 16.

  The operating member 40 has a cylindrical stem 44 raised from a cylindrical piston 42 in which the inner surface of the body portion 10 is fitted so as to be movable up and down, and a nozzle head 46 is attached to the upper end portion of the stem 44. In the illustrated example, a connecting pipe portion 48 that hangs down from the top wall rear surface of the nozzle head is fitted to the upper end portion of the stem 44. The connecting pipe portion 48 communicates with the nozzle 50. A discharge valve 45 is formed in the upper portion of the stem 44. Further, the outer peripheral wall 47 of the nozzle head 46 is screwed into the outer cylinder portion 32 of the retaining member 26.

  The spring 52 is interposed between the lower part of the valve mechanism 36 and the lower part of the operating member 40.

  According to the above configuration, when the outer peripheral wall 47 of the nozzle head 46 is screwed off from the outer cylindrical portion 32 of the retaining member 26 after the liquid ejector is attached to the mouth and neck portion of the liquid container, the elastic force of the spring 52 causes the nozzle to The head 46 is raised. By raising and lowering the nozzle head 46, the liquid can be sucked into the pump cylinder 2 from the liquid container via the suction valve 38, and the liquid can be ejected from the nozzle 50 via the discharge valve 45.

In the present invention, thereby forming a thin torso 10 of the pump cylinder 2, as shown in FIGS. 2 and 3, for the entire outer peripheral surface of the body portion 10, a plurality of and presence equal distance r _alpha A rigid rib 12 is provided vertically. The plurality of rigid ribs 12 are formed so as to extend over substantially the entire vertical direction of the body portion 10 with the same length. Further, in the illustrated example, the thickness of the body portion 10 other than the portion where the rigid rib is formed is smaller than the thickness of the head portion 4 and the leg tube portion 18.

The height of the rigid rib 12 h is preferably smaller than the distance r _alpha rigid ribs 12 each other shown in FIG. Otherwise, the weight of the pump cylinder 2 may increase instead.

The circumferential width t _L of the rigid rib 12 is preferably less than or equal to half the thickness t ₁ of the body portion 10 excluding the rigid rib forming portion. By doing so, it is possible to reduce the risk of sink marks on the inner peripheral surface of the trunk portion 10.

[Example]
{Conventional example}
The procedure for thinning the pump cylinder according to the present invention will be described with reference to a specific example. FIG. 8 shows an example of a conventional pump cylinder. Its thickness t ₀ of the barrel is 1.2 mm, the weight of the body is 2.6 g, the total weight of the pump cylinder is assumed to be 5.0 g.

{Comparison}
It is assumed that the thickness of the trunk portion is reduced without attaching a rigid rib (see FIG. 7). For example, if the thickness t ₁ of the barrel and 0.75 mm, the weight of the body is 1.49 g, and the total weight of the pump cylinder becomes 3.46 g. However, this causes a problem that the strength of the body portion is insufficient, and for example, the body portion bulges outward or extends upward due to sliding with the piston.

{Example}
Therefore, as shown in FIGS. 1 to 4, it is considered that a rigid rib 12 is attached to the outer peripheral surface of the body portion 10. The maximum thickness t _max of the body portion 10 is [the thickness t ₁ of the body portion other than the location where the rigid rib is attached] + [the height h of the rigid rib]. The thickness t ₁ of the body portion is set to 0.75 mm which is the same as the above-mentioned comparison, and is set to 0.4 mm, for example, so that the maximum thickness of the body portion 10 does not exceed the thickness of 1.2 mm of the conventional example. The number of rigid ribs 12 is 25 as shown. The material of the pump cylinder 2 can be PP (polypropylene), for example. As a result, the weight of the body 10 was 1.63 g, and the total weight of the pump cylinder 2 was 3.59 g. Thereby, it becomes lighter than a conventional product and can secure strength.

A method of designing a pump cylinder in which a rigid rib 12 having a width t _L is attached to a body portion 10 having a thickness t ₁ from a configuration of a conventional pump cylinder having a body portion having a thickness t ₀ will be described with reference to FIGS. This will be described with reference to FIG.

FIG. 6 is a cross-sectional view of the pump cylinder when t ₁ + t _L > t ₀ and a partially enlarged view thereof. In the drawing, the range height h of the rigid rib 12 satisfies Equation 1 (h <r _α), also width t _L of the rigid ribs 12, respectively in the range satisfying Equation _{2 (t L ≦ t 1/} 2) The size is close to the upper limit. However, in this case, depending on the number of the rigid ribs 12, the cross-sectional area of the pump cylinder becomes excessively large.

On the other hand, in the example of FIG. 5, the width t _L of the rigid rib 12 does not exceed the width (t ₀ -t ₁ ) obtained by thinning the body of the pump cylinder. In other words, the following equation holds.
[Formula 3] t ₁ + t _L <t ₀

By using Formula 3 and Formula 1 (h <r _α ) described above, it is possible to reliably reduce the weight of the pump cylinder. Then, by adjusting the degree to which the height h of the rigid rib 12 is made smaller than r _α , a required amount of weight reduction that can easily realize the weight reduction of the pump cylinder can be achieved.

Further, the ratio of the thickness before and after the body portion 10 of the pump cylinder 2 is thinned is a = t ₁ / t ₀ . In the case of thinning the pump cylinder 2 from the form of FIG. 8 to FIG. 1, a = 0.75 / 1.2 = 0.625. If the range in which thinning is performed in a common sense is expressed as Equation 3 using a with 1 <a ≦ 0.5, t ₁ + t _L <a ⁻¹ × t ₁ , the following equation is obtained.
[Formula 4] t _L <(a ⁻¹ −1) × t ₁ (where a is a constant and 1 <a ≦ 0.5)
It is possible to design the configuration of the pump cylinder C so as to satisfy the condition of this equation.

2 ... Pump cylinder 4 ... Head 4a ... Lower half 4b ... Upper half 6 ... Hut 7 ... Packing
8 ... Projection ridge 10 ... Body 11 ... Vent 12 ... Rigid rib
16 ... Inward flange 18 ... Leg tube
20 ... Mounting member 22 ... Mounting tube 23 ... Flange-shaped top wall
26 ... Retaining member 28 ... Ring top wall 30 ... Retaining cylinder part 32 ... Outer cylinder part 34 ... Fitting cylinder part
36… Valve mechanism 38… Suction valve
40 ... Actuating member 42 ... Cylindrical piston 44 ... Stem 45 ... Discharge valve
46 ... nozzle head 47 ... outer circumferential wall 48 ... connecting tube portion 50 ... nozzle 52 ... distance P ... suction pipe between the spring h ... rigid rib height r _alpha ... rigid ribs
t ₁ ... trunk thickness t _L ... rigid rib width

Claims (2)

It has a large-diameter cylindrical head (4) with a collar (6) around it, and a medium-diameter cylindrical trunk (10) from the lower end of the head (4), A pump having a vent hole (11) in the upper part of the body (10), each of which has a small-diameter cylindrical leg tube (18) suspended from an inward flange (16) attached to the lower end of the inner surface of (10) In the cylinder,
The cylindrical wall of the body (10) is formed thinner than the head (4), and the entire height of the body (10) is approximately equal to the entire length of the body (10). A plurality of rigid ribs (12) are vertically arranged at equal intervals,
The height (h) at which the rigid rib (12) protrudes in the radial direction of the body portion (10) is made smaller than the circumferential distance (r _α ) between the rigid ribs (12),
The circumferential width (t _L ) of the rigid rib (12) is less than half the radial thickness (t ₁ ) of the cylindrical wall of the body (10), and the pump cylinder for a liquid ejector . A pump cylinder (2) for a liquid ejector according to claim 1, an actuating member (40) having a cylindrical piston in the lower half part capable of moving up and down the inner surface (10) of the pump cylinder (2), A liquid ejector comprising a spring (52) interposed between a lower half portion of an operating member (40) and a lower portion of a pump cylinder (2).