Patent Description:
The present disclosure relates generally to a linear guide mechanism for a reciprocating container forming apparatus, and more particularly, to a self-lubricating linear guide bushing for reciprocating canning and bottling machinery.

Canning and bottling machinery in the food and beverage industry utilize a rotating carousel that includes multiple housings secured thereto, each of which has a ram (e.g., shaft) with one or more cam-followers attached thereto. The carousel, the housings and the cam-followers rotate around a stationary cam that engages each of the cam-followers. The rotation of the carousel causes the cam-followers to transmit the rotary motion into linear sliding rams. These rams move at high speed and perform various forming functions on aluminum, tin, plastic, composites, polymers, or steel. The guide bushings are in place to guide each ram through its stroke and to keep the ram concentric with the housing. Such operation involves high friction between the ram and housing, which generates heat, wear, or slop. Some bushings according the conventional art wear <NUM> inches or more in a six-month period and need to be replaced due to loss of concentricity with the shaft. Rams according to the conventional art rely on greased bronze for reducing friction and wear. However, the greases can contaminate the containers that the food or beverages are contained in. Additionally, bronze bushings are relatively heavy and require significant power dissipation of the machinery in use. Typically, alternatives to bronze bushings cannot withstand high-speed sliding interfaces and high temperatures generated by the sliding. The high-speed sliding can lead to overheating and premature failure of bushings. <CIT> discloses a linear guide mechanism according to the preamble of claim <NUM>.

Thus, there is a need for an improved linear guide bushing that overcomes the foregoing problems.

According to the invention, there is a linear guide mechanism for a reciprocating container forming apparatus. The linear guide mechanism includes a housing having an inside housing surface that defines a bore extending through the housing coaxial with a longitudinal axis. A shaft is disposed at least partially in the bore and is reciprocatably (i.e., back and forth oscillatory motion) and linearly moveable in the bore along the longitudinal axis. The shaft has an exterior shaft surface. A self-lubricating liner is disposed in the bore between the inside housing surface and the exterior shaft surface. The self-lubricating liner has an inside liner surface that is in sliding engagement with the exterior shaft surface of the shaft. The self-lubricating liner has an exterior liner surface and the linear guide mechanism comprises another self-lubricating liner spaced apart from the self-lubricating liner.

In some embodiments, the self-lubricating liner is adhered to the inside housing surface. In some embodiments, the linear guide mechanism further includes a bushing disposed in the bore. In some embodiments, the bushing has an exterior bushing surface and an inside bushing surface. In some embodiments, the exterior bushing surface is secured to the inside housing surface. In some embodiments, the exterior liner surface is secured to the inside bushing surface. In some embodiments, the self-lubricating liner has an annular configuration. In some embodiments, the bushing has an annular configuration. In some embodiments, the self-lubricating liner has a dynamic coefficient of friction of <NUM> to <NUM> when contact pressure between the inside liner surface and the exterior shaft surface is less than <NUM> ksi (i.e., kilopounds per square inch) and a relative speed between the inside liner surface and the exterior shaft surface are up to <NUM> to <NUM> inches per second. In some embodiments, the self-lubricating liner is configured to withstand temperatures of up to <NUM> to <NUM> degrees Fahrenheit.

In some embodiments, the self-lubricating liner includes polytetrafluoroethylene mono-filament fibers interwoven with support fibers encapsulated in a resin. In some embodiments, the support fibers are selected from the group consisting of fiberglass, Dacron®, polyester, cotton, Nomex®, Kevlar® and combinations thereof. In some embodiments, the resin is selected from the group consisting of polyester, epoxy, phenolic, urethane, polyimide, polyamide, acrylics, cyanoacrylates, silicones, polysulfides, anaerobics, and elastomeric adhesives. In some embodiments, the self-lubricating liner has a predetermined axial length configured to maintain the contact pressure between the inside liner surface and the exterior shaft surface at less than <NUM> ksi.

In the invention, the linear guide mechanism further includes another self-lubricating liner spaced apart from the self-lubricating liner. In some embodiments, the linear guide mechanism further includes another bushing spaced apart from the bushing. In some embodiments, the bushing includes at least one of an aluminum alloy, a titanium alloy, a bronze alloy, a beryllium alloy, and a magnesium alloy. In some embodiments, the bushing includes a lattice or honeycomb structure. In some embodiments, the lattice or honeycomb structure is manufactured by a three-dimensional (3D) printing process. In some embodiments, the bushing includes a groove extending axially along the inside bushing surface and radially outward towards the exterior bushing surface. In some embodiments, the groove radially terminates between the inside bushing surface and the exterior bushing surface. In some embodiments, the groove extends into the self-lubricating liner. In some embodiments, the groove is configured to receive an anti-rotation device. In some embodiments, the groove is configured to convey a coolant medium. In some embodiments, the self-lubricating liner is configured to sustain wear of less than seven thousandths of an inch after continuous linear sliding operation of the shaft in the self-lubricating liner for one year.

Any of the foregoing embodiments may be combined.

Referring now to the Figures, which are exemplary embodiments of the invention, and wherein the like elements are numbered alike:.

As shown in <FIG>, a linear guide mechanism <NUM> for a reciprocating container forming apparatus is provided. The linear guide mechanism <NUM> includes a housing <NUM> having an inside housing surface 12E that defines a bore <NUM> extending through the housing <NUM> coaxial with a longitudinal axis L. In some embodiments, as shown in <FIG>, a shaft <NUM> is disposed at least partially inside the bore <NUM> and is reciprocatably (i.e., back and forth oscillatory motion) and linearly moveable in the bore <NUM> along the longitudinal axis L. The shaft <NUM> has an exterior shaft surface 30E.

Two self-lubricating liners <NUM>, each having an annular configuration, are disposed in the bore <NUM> between the inside housing surface 12E and the exterior shaft surface 30E. The self-lubricating liners <NUM> are spaced apart from each other. Each self-lubricating liner <NUM> has an inside liner surface 40E that is in sliding engagement with the exterior shaft surface 30E of the shaft <NUM>. Each self-lubricating liner <NUM> has an exterior liner surface 40F. In other embodiments, there are more than two self-lubricating liners <NUM>.

The linear guide mechanism <NUM> further includes a bushing <NUM>, which has an annular configuration and is disposed in the bore <NUM>. The bushing <NUM> has an exterior bushing surface 20F and an inside bushing surface 20E. The exterior bushing surface 20F is secured to the inside housing surface 12E. The exterior liner surface 40F is secured to the inside bushing surface 20E. In some embodiments, the bushing <NUM> is press fit into the housing <NUM>. In some embodiments, each axial end of the bushing <NUM> is axially aligned with an axial end of a respective self-lubricating liner <NUM>. In some embodiments, the self-lubricating liners <NUM> are disposed entirely inside the bushing <NUM>. The position of the self-lubricating liners <NUM> as shown in <FIG> is advantageous for maintaining functional stiffness of the bushing <NUM> for alignment and positional tolerance, while serving to reduce the frictional drag on the shaft <NUM>. The surface area of the inside liner surface 40E influences the contact pressures experienced by the self-lubricating liners <NUM>.

In some embodiments, several smaller bushings <NUM> are installed instead of one large bushing <NUM>, e.g., to control the contact area of the self-lubricating liners <NUM> or to reduced system weight. For example, referring to the embodiment of <FIG>, the linear guide mechanism <NUM> includes two bushings <NUM> spaced apart from one another. In some embodiments, the bushings <NUM> and the self-lubricating liners <NUM> are of the same length. In some embodiments, one of the bushings <NUM> is axially aligned with one of the self-lubricating liners <NUM>, and the other bushing <NUM> is axially aligned with the other self-lubricating liner <NUM>. In other embodiments, more than two bushings <NUM> spaced apart from one another are used.

Some embodiments of the linear guide mechanism <NUM> lacks the bushing <NUM>. For example, in <FIG>, there is no bushing <NUM>. Instead, the self-lubricating liner <NUM> is adhered directly to the inside housing surface 12E.

As shown in <FIG>, in some embodiments, the bushing <NUM> has a groove <NUM> extending axially along the inside bushing surface 20E and radially outward towards the exterior bushing surface 20F. The groove <NUM> radially terminates between the inside bushing surface 20E and the exterior bushing surface 20F. In some embodiments, the groove <NUM> has rounded ends. In some embodiments, the groove <NUM> extends into the self-lubricating liner <NUM>. In some embodiments, the groove <NUM> is configured to receive an anti-rotation device. For example, in some embodiments, the groove <NUM> is a keyway used for an anti-rotation device to keep the shaft <NUM> from rotating in the housing <NUM>. In some embodiments, the groove <NUM> is configured to convey a fluid such as a coolant medium or lubricant. In some embodiments, the bushing <NUM> also has a lip <NUM> for receiving or compressing a seal.

The self-lubricating liner <NUM> is able to withstand heat generated from loading and movement conditions. Referring to <FIG>, in some embodiments, the self-lubricating liner <NUM> includes polytetrafluoroethylene mono-filament fibers 80A, 80B interwoven with support fibers 80C, 80D encapsulated in a resin <NUM>. In some embodiments, the polytetrafluoroethylene mono-filament fibers 80A, 80B include micro, nano, etched, or Torey® flock fibers cut at <NUM>-<NUM> lengths. In some embodiments, the support fibers 80C, 80D include fiberglass, Dacron®, polyester, cotton, Nomex®, Kevlar®, or combinations thereof. In some embodiments, the resin <NUM> includes polyester, epoxy, phenolic, urethane, polyimide, polyamide, acrylics, cyanoacrylates, silicones, polysulfides, anaerobics, elastomeric adhesives, or other suitable resins. In some embodiments, the self-lubricating liner <NUM> includes additives for enhancing composite performance.

In some embodiments, the self-lubricating liner <NUM> has a predetermined axial length configured to maintain contact pressure between the inside liner surface 40E and the exterior shaft surface 30E at less than <NUM> ksi. In some embodiments, the self-lubricating liner <NUM> has a radial thickness of <NUM>-<NUM> inches in the original as installed state, before operation. In some embodiments, the self-lubricating liner <NUM> has a dynamic coefficient of friction of <NUM> to <NUM> when contact pressure between the inside liner surface 40E and the exterior shaft surface 30E is less than <NUM> ksi and a relative speed between the inside liner surface 40E and the exterior shaft surface 30E is <NUM> to <NUM> inches per second. In some embodiments, the self-lubricating liner <NUM> is configured to withstand temperatures of up to <NUM> to <NUM> degrees Fahrenheit. In some embodiments, the self-lubricating liner <NUM> is capable of maintaining concentricity tolerances of the shaft <NUM> relative to the self-lubricating liner <NUM>. Specifically, in some embodiments, the self-lubricating liner <NUM> wears less than seven thousandths of an inch in one year of continuous linear sliding operation of the shaft <NUM> within the self-lubricating liner <NUM>. Seven thousandths of an inch represents about <NUM>-<NUM> percent of the original thickness of the liner <NUM>.

In some embodiments, the bushing <NUM> includes at least one of an aluminum alloy, a titanium alloy, a bronze alloy, a beryllium alloy, and a magnesium alloy. In some embodiments, the bushing <NUM> includes a lattice or honeycomb structure. In some embodiments, the lattice or honeycomb structure is manufactured by a 3D printing process. In some embodiments, the bushing <NUM> is lightweight to help minimize the weight of the linear guide mechanism <NUM>. Minimizing the weight reduces the power needed to run the machine having the linear guide mechanism <NUM>. In some embodiments, minimization of the weight of the linear guide mechanism <NUM> is achieved by: using lightweight materials such as aluminum or titanium that without the self-lubricating liner <NUM> would have undesirable friction and wear performance; incorporating weight reduced geometries such as honeycomb 3D printed materials that would otherwise not be appropriate for a sliding bushing; or integrating the bushing <NUM> and the housing <NUM> into a single component in which the self-lubricating liner <NUM> is applied directly to the housing <NUM> to reduce potential tolerance stack-up.

<FIG> shows various examples of lattice structures suitable for making up the bushing <NUM>. In one example, a lattice structure <NUM>" has support members <NUM>". The distribution of the support members <NUM>" is such that there is a higher concentration of the support members <NUM>" at a first end 30A" than at a second end 30B". That is, the spaces <NUM>' between the support members <NUM>" increase in volume moving from the first end 30A" to the second end 30B". In the same manner, in some embodiments, the distribution of support members <NUM>" making up the bushing <NUM> is such that there is a higher concentration of the support members <NUM>" at locations in the bushing <NUM> where stress is likely to be high. For example, in some embodiments, there is a relatively high concentration of the support members <NUM>" in the bushing <NUM> proximate the interface between the bushing <NUM> and the self-lubricating liner <NUM>.

In another example shown in <FIG>, lattice structure 30Q3 is made up of randomly arranged or pseudo-randomly arranged support members 32Q3. Similarly, in yet another example, lattice structure 30Q4 is made up of randomly arranged or pseudo-randomly arranged support members 32Q4. Other examples of lattice structures include lattice structure 30Q5, lattice structure 30Q6, and lattice structure 30Q7. In various embodiments, the bushing <NUM> is made up of any one or any combination of any two or more of lattice structure <NUM>", lattice structure 30Q3, lattice structure 30Q4, lattice structure 30Q5, lattice structure 30Q6, and lattice structure 30Q7.

The linear guide mechanism <NUM> according to the present disclosure has the advantage of providing for a grease free assembly, which helps to reduce grease related issues like contamination adhesion or food contamination. The linear guide mechanism <NUM> according to the present disclosure is capable of withstanding speeds and heat generated in sustained canning and bottling operations.

Claim 1:
A linear guide mechanism (<NUM>) for a reciprocating container forming apparatus, the linear guide mechanism (<NUM>) comprising:
a housing (<NUM>) having an inside housing surface (12E) that defines a bore (<NUM>) extending through the housing (<NUM>) coaxial with a longitudinal axis (L);
a shaft (<NUM>) disposed at least partially in the bore (<NUM>) and being reciprocatably and linearly moveable in the bore (<NUM>) along the longitudinal axis (L), the shaft (<NUM>) having an exterior shaft surface (30E); and
a self-lubricating liner (<NUM>) disposed in the bore (<NUM>) between the inside housing surface (12E) and the exterior shaft surface (30E), the self-lubricating liner (<NUM>) having an inside liner surface (40E) that is in sliding engagement with the exterior shaft surface (30E) of the shaft (<NUM>) and the self-lubricating liner (<NUM>) having an exterior liner surface (40F), characterised in that the linear guide mechanism further comprises
another self-lubricating liner (<NUM>) spaced apart from the self-lubricating liner (<NUM>).