Patent Description:
There are several types of apparatus that can be employed for industrial and structural uses in order to absorb energy, such as from a transmitted load. For example, high cycle blow molding apparatus employ mold or die halves which can "bounce" as a consequence of opening and closing the dies, i.e., principally the impact of closing the dies. Such bounce can produce defects in the molded product resulting in increased scrap, additional maintenance and increased downtime of the blow molding apparatus. Consequently, the throughput/efficiency of the blow molding apparatus is adversely impacted. To alleviate difficulties associated with the foregoing, conventional shock absorbers have been employed to convert the impact energy of the bounce as dissipated heat.

More specifically, these shock absorbers typically include at least one piston assembly, which is disposed within an enclosed cavity or housing, and coupled to the machine under load. In operation, a transmitted shock or impact load creates: (i) movement of the piston assembly, (ii) a change in pressure of a contained incompressible hydraulic fluid in the cavity, and (iii) flow through at least one orifice that results in conversion of the applied kinetic energy to heat. The force of the transmitted shock or impact load is reduced by the shock absorber, thereby lowering the transmitted load from other parts of the machine or other attached structure.

For proper operation, shock absorbers as described above require at least one dynamic seal interposed between the moving parts to prevent fluid leakage, and/or the ingestion of air into the hydraulic cavity of the housing. Inasmuch as blow molding or other apparatus routinely undergo a high number of cycles, it is common for the dynamic seals to fail prematurely, requiring costly repair and maintenance. Additionally, the replacement of either the hydraulic seals, or the entire shock absorber assembly, can adversely impact manufacturing schedules or other time-critical events for the purpose of repairing and/or replacing the affected assemblies. It will be appreciated that avoiding down-time for such high throughput machines is an ongoing and important goal. An elastic-walled hydraulic mounting for automobile engines of <CIT> is designed to absorb low frequency high amplitude engine vibration whilst transmitting high frequency low amplitude support vibration. It has primary and secondary cells containing hydraulic fluid. Part of the cell walls may be of rubber and a bleeding orifice communicates between the cells. The mounting comprises a hollow unit which is traversed axially by a vertical bolt and subdivided by a horizontal metal diaphragm plate. The top of the bolt attaches to an engine bracket, and external flanges at diaphragm level attach to the chassis. Metal cones with rubber rings form the top and bottom of the unit resp. and inclined plates from the diaphragm form the side walls. The second fluid chamber of <CIT> is incorporated with a volume accommodating a medium restricted by a second limiting device. An intermediate component is arranged between the first and second fluid chambers and has at least one shock absorbing aperture through which medium can flow from the first fluid chamber into the second and vice versa. The shock absorber of <CIT> has a base with a central reservoir containing hydraulic fluid. The fluid container has a central column with a central to receive a needle valve. The outside of the column is fitted with a cone made from elastic material. The top of the absorber has a cover plate over a cylinder in the base. The needle valve is fixed to the underside of the plate and the outside of the cone is fixed to the inside of the inner cylinder.

It is, therefore, desirable to provide an effective and reliable shock absorbing apparatus which mitigates the need for dynamic seals and the failure modes associated therewith. Furthermore, it will be appreciated that there is a competing and prevalent need to reduce complexity, improve reliability, and lower associated costs of such high cycle, dynamic shock absorbing apparatus.

The shock absorbing apparatus according claim <NUM> is characterized by two pin members disposed in axial relation on opposite sides of the plate and movable disposed in relation to the at least one orifice, in which transmitted loads acting on the flexible housing on either side of the plate cause movement of the two pin members relative to the at least one orifice to create a variable orifice diameter.

In at least one version, the flexible housing can be defined by at least one elastomeric section bonded to at least one support plate. In at least one embodiment, a pair of housing portions are provided, each having at least one elastomeric section bonded to a mounting plate and a striker plate, respectively. In one version, a single orifice is defined in a center plate although this number can be suitably varied and sized to enable damping characteristics to be suitably tuned.

Two shaped pin members are provided to define a variable orifice diameter wherein the pin members can be defined by a tapered configuration that effectively reduces the flow area when one of the pin member is moved into the orifice while under load. In addition and according to at least one embodiment, at least one spring can be provided within the defined housing to provide an additional biasing force along with the restoring force provided by the flexible elastomeric housing and also to prevent a compressive set.

According to another embodiment, the herein described shock absorbing assembly can be configured to receive impact or shock loads at respective ends of the defined flexible interchangeable according to a housing, and in which a biasing spring can be provided in each fluidic chamber in the housing interior such that the adjacent fluid chamber and accumulation chambers are symmetric.

The method for manufacturing a shock absorbing apparatus without requiring sliding hydraulic seals, comprising:.

In one version, the fluidic chambers can be defined using a fixed plate that is disposed within the interior of the flexible housing, in which the fixed plate further includes the at least one orifice. One or more orifice holes can be sized and configured for a desired damping level when fluid is caused to pass therethrough.

Each end of the defined housing, in at least one version, can include at least one striker or contact plate that is axially aligned at an end of the flexible housing with the defined orifice that is configured to effect damping in response to an applied load.

Two pin members are added to the interior of the housing, the pin members could have a tapered configuration that can be translated axially into and out of the orifice based on loading conditions, and thereby creating a variable orifice diameter. For example and according to one version, the pin member is assembled using fasteners to the striker plate and reduces the effective flow area when moved into the orifice. In at least one version, a pair of tapered pin members can be provided, each of these members being axially and symmetrically aligned with one another.

In addition, at least one spring can also be optionally included within the interior of the housing and more specifically within each of the defined fluidic chambers in order to additionally provide a biasing or restoring force along with the elastomeric material of the housing and/or to prevent compression of the herein described apparatus.

Advantageously, the herein described shock absorbing apparatus is simpler and easier to assemble than prior known versions based on a fewer number of required parts. The herein described shock absorbing apparatus performs reliably, but without requiring reciprocating piston assemblies and associated hydraulic sliding seals. As a result, the herein described apparatus has a longer overall service life as compared to prior designs, and particularly in working environments that are usually characterized by frequent or high loading cycles.

In addition, the herein described apparatus is relatively easy and inexpensive to manufacture as compared to prior art versions. For example, aspects of the housing can be injection molded according to at least one version. In addition, the herein described apparatus is simple in terms of assembly and also for purposes of mounting to a specified structure or machine that is under load for purposes of shock absorption.

For manufacturing purposes, the same mold can be used with various durometer/hardness properties of elastomer to provide stiffness variation. Similarly, different orifice sizes can utilize the same plate "blank". This allows the same components and manufacturing process/tools to be used for multiple applications of the herein described apparatus.

An embodiment will be described in detail, with reference to the following figures, wherein like designations denote like members.

The following relates to an embodiment of a shock absorbing apparatus that relies upon at least one elastomeric element or membrane to define a highly flexible housing containing a hydraulic fluid that can be attached to a structure or machine under load. The apparatus reliably reduces transmitted shock loads from other parts of a machine or other structure.

In the embodiment, the shock absorbing apparatus reduces transmitted shock loads without the requirement for sliding dynamic seals to move a hydraulic fluid through a damping orifice and/or separate spring biasing elements to return the elastomeric membrane to its original shape/configuration for subsequent work cycles. As such, the hydraulic shock absorbing apparatus of the present disclosure is particularly advantageous for use in environments characterized by high cyclic loading such as, for example, blow molding apparatus for fabricating plastic containers/bottles. It will also be readily apparent that the shock absorbing apparatus described herein can be employed for nearly any application that requires impact and/or shock load absorption.

For background purposes, reference is made to <FIG> which depicts a typical shock absorbing apparatus <NUM> comprising a piston assembly <NUM> disposed within, and supported by, a cylinder <NUM> containing a hydraulic damping fluid <NUM>. More specifically, the piston assembly <NUM> includes a piston head <NUM>, at one end, disposed within, and acting against, the hydraulic damping fluid of the hydraulic cylinder <NUM>, and a cylindrical piston rod <NUM>, at an opposing end, connected to the piston head <NUM>.

In operation, the piston assembly <NUM> moves with, and is responsive to, a transmitted impact or shock load of the blow molding apparatus while the cylinder <NUM> is attached to a fixed support, or another portion, of a machine. More specifically, the transmitted shock or impact load causes axial movement of the piston assembly <NUM>, including the piston head <NUM> against the hydraulic fluid, pressurizing same and causing movement of the fluid though at least one defined orifice <NUM> to an accumulator <NUM>. This movement results in a reduction in transmitted force to the remainder of the connected structure as the energy of the shock load is dissipated over the stroke of the unit, i.e., as heat generated by the shearing action of the hydraulic fluid. The piston assembly <NUM> is configured to move axially in a reciprocating fashion in response to the transmission and cessation of load while a biasing coil spring <NUM> stores a portion of the kinetic energy of the piston assembly <NUM> as potential energy in the coil spring <NUM>. With each cycle, the impact load displaces the piston head <NUM> so as to force the damping fluid through the damping orifice <NUM> in the piston head <NUM>. With the cessation of the impact load, the coil spring <NUM> is operative to return the piston assembly <NUM> of the shock absorbing apparatus <NUM> to its initial or original position. To prevent leakage of the contained pressurized hydraulic fluid during movement of the piston head <NUM>, a dynamic (frictional) seal <NUM> is provided. Under conditions typified by high cyclic loading, this dynamic seal <NUM> is prone to failure. Consequently, shock absorbing apparatus of the prior art require frequent replacement which adversely impacts throughput and machine efficiency.

Referring to <FIG> and <FIG>, a shock absorbing apparatus <NUM> in accordance with an exemplary embodiment is defined by a flexible housing <NUM> that is made substantially from a fluid-impermeable elastomeric material. According to this specific embodiment, the shock absorbing apparatus <NUM> is defined by a pair of housing portions <NUM>, <NUM>, as well as an orifice plate <NUM>. Each of the housing portions <NUM>, <NUM> are commonly defined by a section <NUM> of an elastomeric material of suitable shape, in this instance circular, and in which each elastomeric section <NUM> has an outer periphery <NUM> that is bonded to the inner peripheral edge of a mounting plate <NUM>. It will be understood that the shape assumed for the mounting plates <NUM> and elastomeric sections <NUM> is exemplary and other configurations could be contemplated.

An inner periphery <NUM> of each elastomeric section <NUM> is further bonded to a striker plate <NUM>. When assembled, each of the bonded elastomeric sections <NUM> of the housing portions <NUM>, <NUM> form a complementary and substantially C-shaped configuration in which the mounting plates <NUM> each extend radially from the elastomeric section <NUM> and in which the striker plate <NUM> forms the center of each outwardly bowed housing portion <NUM>, <NUM>. In this embodiment, each of the housing portions <NUM>, <NUM>, including the elastomeric material section <NUM>, are identical. It should be noted, however, that each housing portion <NUM>, <NUM> could be configured with different material characteristics. For example, the thickness, shape and or material of the elastomeric sections of the first and second housing portions <NUM>, <NUM> can be varied from one another in order to produce different responses under load. In the described embodiment, the flexible elastomeric sections may be fabricated from a rubber material, including natural rubber, fluoroelastomer, fluorosilione, silicone, EPDM, butyl rubber, nitrile rubber and the like. The flexible elastomeric material employed therein may have a shear modulus greater than about <NUM> bar (<NUM> × <NUM><NUM> psi), a bulk modulus greater than about <NUM> bar (<NUM>×<NUM><NUM> psi), a maximum elongation greater than about <NUM>% from an original size/length, and a durometer of between about between about thirty (<NUM>) to about seventy (<NUM>) on a Shore A hardness scale.

Each mounting or support plate <NUM> according to this embodiment is formed as a substantially planar section made from a suitable metal, plastic or elastomeric material, provided each of the plates can provide structural support. In at least one version, each of the mounting plates <NUM> could also be made from an injection molded plastic. The mounting plates <NUM> are defined by an inner peripheral end and an opposing outer peripheral end with a circular opening being formed at the center of each mounting plate <NUM> which is bounded by the inner peripheral edge of the mounting plate <NUM>. An annular groove <NUM> is formed on an opposing surface of each mounting plate <NUM> at the peripheral inner end relative to the bonded elastomeric section <NUM>. The bonding of the elastomeric sections <NUM> to the striker and base plates <NUM>, <NUM> can utilize adhesives, activated during the molding process, or as a post-molding standalone agent that creates or otherwise creates a durable fluid-tight seal. According to this embodiment, the annular groove <NUM> of each housing portion <NUM>, <NUM> is configured to receive an O-ring <NUM> or other form of static sealing member.

The striker plates <NUM> are made from a durable material, such as a thermoset wear-resistant plastic and are commonly defined by a substantially cylindrical configuration. Each striker plate <NUM> is sized to substantially correspond with the thickness of the solid elastomeric section <NUM> and includes a center through opening <NUM> sized to receive a fastener <NUM>, such as a counter sunk fastener, the fastener <NUM> having a length that extends into the interior <NUM> of the housing <NUM> when attached, as shown in <FIG>. Each of the two mounting plates <NUM> and the sandwiched orifice plate <NUM> are defined by an aligned series of mounting holes <NUM> which are exterior to the formed flexible housing <NUM>. The mounting holes <NUM> enable attachment of the flexible housing <NUM> to a structure or machine (not shown) using fasteners (not shown). It should be noted that this embodiment depicts striker or impact plates <NUM> as part of each housing portion <NUM>, <NUM>. Alternatively, only one of the housing portions can be provided with a striker or impact plate <NUM>.

The orifice plate <NUM> according to this exemplary embodiment is defined by a planar member made from plastic, metal, composite or other durable material that is sized and configured to extend through the interior of the defined housing <NUM> with the outer end of the orifice plate <NUM> being sized to complement the mounting plates <NUM>, including the mounting holes <NUM>. At least one orifice <NUM> formed at substantially the center of the orifice plate <NUM> is axially aligned according to this embodiment with the through openings <NUM> of the striker plates <NUM>, when assembled. The orifice plate <NUM> divides the hollow interior <NUM> of the housing <NUM> into adjacent substantially hemispherical chambers <NUM>, <NUM> that are fluidically interconnected by the defined orifice <NUM>. In the context used herein, "fluidically" means a fluid connection, or the type of connection, between two portions, cavities or chambers of the hydraulic shock absorbing apparatus, i.e., that the cavities are in fluid communication. Though only a single orifice <NUM> is provided according to this embodiment, one or more orifice(s) can be suitably provided and sized in order to effectively tune the amount of damping required. According to this embodiment, the orifice plate <NUM> further includes a pair of outwardly extending annular rings <NUM> radially exterior to the housing <NUM> that are sized and configured to fit within corresponding grooves <NUM> which are formed within the inner facing side of a corresponding mounting plate <NUM> to further retain the assembly <NUM> in a press fit. Following the above described press fit assembly of the housing portions <NUM>, <NUM>, a quantity of hydraulic fluid <NUM> can be added to the hollow interior <NUM> of the housing <NUM>. According to this embodiment, the hydraulic fluid <NUM> can be added to the through opening <NUM> formed in one of the striker plates <NUM>, forming a sealable fill port, and prior to attaching the fastener <NUM>.

According to this specific embodiment and still referring to <FIG> and <FIG>, at least one pin member <NUM> can be optionally disposed within the hollow interior <NUM> of the defined housing <NUM>. More specifically and according to this exemplary embodiment, a pair of hollow pin members <NUM> can optionally be provided, each pin member <NUM> having a conical tapered configuration defined by a distal end opening <NUM> having a first diameter and a proximal end opening <NUM> having a second diameter that is larger than the first diameter. According to this exemplary embodiment, the pin members <NUM> each include a proximal opening <NUM>, <FIG>, that receives the extending end of fasteners <NUM> at each end of the housing <NUM>. When positioned in the manner shown in <FIG>, the application of a transmitted axial load <NUM> to the housing <NUM> will cause the pin members <NUM> to be moved into the orifice <NUM>, thereby reducing the effective flow area and creating a variable orifice diameter.

In addition, a pair of springs <NUM> can be optionally provided in the hollow interior <NUM> and aligned with the orifice <NUM> and the striker plates <NUM> in order to provide a biasing or restoring force in addition to that of the elastomeric housing <NUM>. In this embodiment, each of the springs <NUM> are mounted between the striker plate <NUM> and the orifice plate <NUM> in each respective fluidic chamber <NUM>, <NUM> with the pin member <NUM> extending through the center of the spring <NUM>. According to this specific embodiment and when assembled, the springs <NUM> are axially aligned with the orifice <NUM>, as well as the center openings <NUM> of each striker plate <NUM> and with the spring ends being in engagement between a striker plate <NUM> and the orifice plate <NUM> in each defined fluidic chamber <NUM>, <NUM>.

Fasteners (not shown) from a machine or other structure, such as threaded or other forms of fasteners, secure the herein described optional assembly through the aligned openings <NUM> of the mounting plates <NUM> and the sandwiched orifice plate <NUM>, thereby fixedly attaching the assembly to a structural component.

In operation and still referring to <FIG> and <FIG>, the herein described shock absorbing apparatus <NUM> can be disposed between respective die portions of a blow molding machine (not shown) and mounted using fasteners attached through the aligned holes <NUM> of the mounting plates <NUM> and the orifice plate <NUM>. As attached, one of the striker plates <NUM> is aligned in relation to the movable die portion (not shown) of the machine. As the die is closed, the die engages the striker plate <NUM> as depicted by arrow <NUM>, generating a compressive load against the flexible elastomeric housing <NUM> and more specifically the elastomeric section <NUM> of the housing <NUM>. This causes an inward deformation of the flexible housing <NUM>, resulting in the hydraulic fluid <NUM> contained in the first fluidic chamber <NUM> to be pressurized and forced through the orifice <NUM> and into the adjacent second fluidic chamber <NUM> with the optional tapered pin member <NUM> also being advanced into the orifice <NUM> based on the application of load.

Claim 1:
Shock absorbing apparatus (<NUM>) comprising:
a flexible housing (<NUM>) substantially formed from at least one fluid-impermeable elastomeric section (<NUM>) and defining an interior,
a plate (<NUM>) disposed within the interior of the housing (<NUM>) and having at least one orifice (<NUM>), the plate (<NUM>) creating adjacent chambers containing a hydraulic fluid that are fluidically connected by the at least one orifice (<NUM>);
at least one mounting plate (<NUM>) for connecting the housing (<NUM>) to a structure that is under load in which transmitted loads acting on the flexible housing (<NUM>) from the structure cause a pressurized hydraulic fluid to move between the adjacent chambers through the at least one orifice (<NUM>) to provide shock absorption;
in which the shock absorbing apparatus (<NUM>) is characterized by two pin members (<NUM>) disposed in axial relation on opposite sides of the plate (<NUM>) and movable disposed in relation to the at least one orifice (<NUM>), in which transmitted loads acting on the flexible housing (<NUM>) on either side of the plate (<NUM>) cause movement of the two pin members (<NUM>) relative to the at least one orifice (<NUM>) to create a variable orifice diameter.