The present invention relates generally to clamping devices, and more particularly to a sliding-head pin clamp having a clamping mechanism configured to be positioned at four 90-degree-opposed positions, as well as a locking mechanism having a pilot-operated check valve integrated into a body of the pin clamp and configured to selectively retain the clamping mechanism in a clamped position.
Pneumatically operated clamps are used in a variety of industries for securing objects in a position for various purposes. In automobile manufacturing, for example, stamped metal body parts are assembled on a pallet, wherein various pre-fabricated individual initial components or other parts of an automobile body are positioned on the pallet and clamped in place. Once clamped, the individual initial components are welded together, therein generally defining the automobile body. A typical pallet has at least four clamping locations (e.g., one clamping location is assigned to each of four corners of the automobile body), wherein at least one pin clamp apparatus is precisely affixed to the pallet at each clamping location via a riser (e.g., a weldment having precise dimensions).
Accordingly, once clamped in place by the pin clamps, the precise positioning of the individual initial components of the automobile body is assured at an initial station along an assembly line, and subsequent positioning and welding of subsequent components to the automobile body can be further generally assured, assuming the pin clamp(s) retain their clamping force as the automobile body progresses along the assembly line. Once assembly of the automobile body is complete, the pin clamps release the automobile body from the pallet for subsequent assembly, such as for painting and final assembly.
Conventionally, the pallet is referenced at a hardened steel position on the pallet, and the risers (and associated pin clamps) are further referenced to the hardened steel position. Typically, the pin clamps are pneumatically operated, wherein initial clamping of the pin clamps is performed at the initial station by pneumatic pressure. In order to maintain the precise positioning of the automobile body along the assembly line, the pin clamps at the four corners must typically remain clamped until assembly of the automobile body (often referred to as a “white body”) is finished. However, once the initial components are positioned and welded at the initial station, pneumatic pressure is removed from the pin clamps so that the pallet can be transferred to subsequent welding and assembly stations. Pneumatic pressure is typically not reintroduced to the pin clamps until the white body is completely assembled, which is when the white body is unclamped from the pallet and ready for the subsequent assembly process. Conventionally, the white body is held in place by the clamping pins during the absence of pneumatic pressure via complex mechanical components within the clamping pin apparatus, such as cams, gears, or other mechanisms.
During initial setup and/or day-to-day operation in the assembly process, it is also sometimes necessary to modify an orientation of the pin clamps for various reasons, such as to permit access for robots to enter areas of the automobile body otherwise blocked by a pin clamp. Conventionally, a pin clamp is configured to be initially secured to the riser, whereby the orientation and referencing of the pin clamp with respect to the hardened steel position on the pallet is accurately measured. Conventional pin clamps have been provided that can clamp a workpiece with respect to a mounting surface of the pin clamp, or in a position that is 180-degrees opposed to the initial position. As such, when clamping is desired at positions other than the initial or 180-degree opposed position of the pin clamp, the riser is typically modified or changed, and the pallet is referenced again, at significant cost and consumption of time. Such a change can cause many problems, especially when a large number of pallets are involved (e.g., 800-1000 pallets are not uncommon in an assembly line). Furthermore, customized risers can be quite expensive, where the customized riser is designed to provide specialized location capabilities.
Further, in order to provide a rotation of 90 degrees in a conventional pin clamp, a time and cost-intensive reconfiguration of the fixture or pallet would typically be required. Conventionally, a riser is mounted to the pallet wherein a reconfiguration or rotation of the conventional pin clamp could require a different riser (e.g., a customized E-W replacing a N-S riser) to be placed on the pallet. Such a change can cause many problems when a large number of pallets are required. Customized risers are typically very expensive, where the riser is designed to provide specialized location capabilities. The present invention utilizes a standard riser North American Automotive Manufacturing (NAAM) riser.
The present disclosure provides a novel sliding head locking pin clamp, wherein an orientation of a clamping member is configured to be readily adjustable in one of four 90-degree opposed positions. In accordance with on exemplary aspect, a sliding head locking pin clamp is provided having a housing with a housing bore extending axially therethrough along a first axis. An end cap has an end cap bore extending therethrough along the first axis, wherein the end cap is operably coupled to a first end of the housing.
According to one example, a shaft has a shaft bore extending through the shaft along the first axis, wherein an outer diameter of a first end of the shaft generally defines a first portion of a locating pin. The first portion of the locating pin is in axial sliding engagement with at least a first portion of the end cap bore. The shaft has a shaft hole extending radially through the shaft along a second axis, wherein the second axis is perpendicular to the first axis. The shaft further has a shaft guide rod generally fixedly positioned in the shaft hole.
A piston is further coupled to the shaft and is in sliding engagement with the housing bore to linearly translate the shaft between a first axial position and a second axial position along the first axis. A slider has a slider hole extending radially therethrough, wherein the shaft guide rod is in linear sliding engagement with the slider hole, therein providing a linear translation of the slider with respect to the shaft along the second axis between a first radial position and a second radial position. The slider has a rod member extending through a first end of shaft bore and comprising a tip having an engagement lip, wherein the tip of the rod member generally defines a second portion of the locating pin. A cam follower also extends radially from the slider.
A cam block has a cam block bore extending into the cam block along the first axis, wherein the cam block comprises a cam channel defined in a sidewall of the cam block bore. A portion of the slider is configured to reside within the cam block bore and wherein the cam follower is in sliding engagement with the cam channel. In the first axial position and first radial position, the first and second portions of the locating pin are configured to pass through a locating hole of a workpiece. In the second axial position and second radial position, the rod member is configured to clamp the workpiece between the engagement lip and the end cap. The first radial position and second radial position are governed by the sliding engagement between the shaft guide rod and the slider hole, and the sliding engagement between the cam follower and the cam channel upon the linear translation of the shaft between the first axial position and second axial position.
In accordance with another exemplary aspect, a check valve is associated with the housing, wherein the check valve is configured to selectively maintain a pneumatic pressure associated with one of a first axial side and a second axial side of the piston when a source of pneumatic pressure is removed from the one of the first axial side and second axial side of the piston.
The present disclosure will be described with reference to the drawings wherein like reference numerals are used to refer to like elements throughout. It should be understood that the description of these aspects are merely illustrative and that they should not be taken in a limiting sense. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be evident to one skilled in the art, however, that the present disclosure may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate description of the present disclosure.
Referring initially to FIGS. 1 and 2A-2B, a sliding head locking pin clamp 100 is provided in accordance with one exemplary aspect of the disclosure. In one example, a housing 102 is provided having a housing bore 104 extending axially into the housing, therein defining a first axis 106. The housing 102, for example, is illustrated in further detail
According to one example, a shaft 114 is provided in the sliding head locking pin clamp 100 shown in FIGS. 1 and 2A-2B.
A piston 134, for example, is further generally fixedly coupled to the shaft 114. The piston 134, for example, is in sliding engagement with the housing bore 104 and configured to linearly translate the shaft 114 between a first axial position 136A and a second axial position 136B along the first axis 106, illustrated in cross-section in
According to another example, as illustrated in FIGS. 1 and 2A-2B, a rod member 144 extends through the shaft bore 116 at the first end 118 of the shaft 114 and comprises a tip 148 having an engagement lip 150, as illustrated in greater detail in
A cam block 156 is further provided having a cam block bore 158 extending into the cam block generally along the first axis 106. The cam block 156 comprises at least one cam channel 160 defined in a sidewall 162 of the cam block bore 158, as illustrated in greater detail in
Accordingly, in the first axial position 136A and first radial position 142A of
It is noted that the at least one cam channel 160 of the cam block 156 of FIGS. 1 and 8A-8C, for example, further allow at least a portion of the locating pin 124 to first translate perpendicularly to the first axis 106, as illustrated in the intermediate position of
In accordance with another exemplary aspect of the disclosure, it is understood that order to provide a rotation of 90 degrees in a conventional pin clamp, a time and cost-intensive reconfiguration of the fixture or pallet would typically be required. Conventionally, a riser is mounted to the pallet wherein a reconfiguration or rotation of the conventional pin clamp could require a different riser (e.g., a customized E-W replacing a N-S riser) to be placed on the pallet. Such a change can cause many problems when a large number of pallets are required. Customized risers are typically very expensive, where the riser is designed to provide specialized location capabilities.
The present invention provides 90 degrees of rotation for the pin clamp 100 (e.g., South, East, North, and West, as illustrated in
In one example of the present disclosure, in order to change direction of clamping of the pin clamp 100 illustrated in
In accordance with another example, a position sensor (not shown) is operably coupled to the housing 102, wherein the position sensor is configured to sense a position of the piston 134 with respect to the housing.
According to another example, as illustrated in
In another example, the present invention maintains clamping force on the workpiece via the pilot-operated check valve 182 that is integrated into the pin clamp 100. The pilot-operated check valve 182 is thus embedded in the pin clamp 100, wherein any pressure held by the pilot-operated check valve is retained in a volume within the housing 102 of the pin clamp. Pneumatic pressure that is applied to the pin clamp 100 (e.g., approximately 80 psi) is retained by the pilot-operated check valve 182. In the present embodiment, the pin clamp 100 is configured to clamp down onto a workpiece (e.g., the white body) with approximately 300 pounds of force, but greater or lesser clamping forces are contemplated. In a conventional clamp, if a catastrophic force, such as a robot accidentally colliding with the workpiece, the conventional pin clamps could potentially be moved a little bit. However, as soon as the catastrophic force ends, the pin clamp would go back to its original clamping.
In the present example, since the pin clamp 100 is pilot-operated, when the clamping is released by pressure on an opposing port, the clamp disengages the workpiece. The check valve 182 generally holds the pneumatic pressure in the cylinder, whereas in conventional pin clamps, the pressure in the cylinder can be compressed (e.g., the piston can move) based on how much force is applied. Alternatively, many complex mechanisms have been used to lock the pin in place, where the number of parts can go up to 50 parts. Since MTBF is halved each time you add a part, every additional part added can decrease the life expectancy of the pin clamp. On the contrary, the present invention has very few parts, is relatively simple, has a lower cost, and significantly higher reliability than conventional pin clamps.
The circuitry for the pilot-operated check valve, for example, is integral to the body or housing 102 of the pin clamp 100. In one example, all pneumatic circuitry is internal to the housing 102, wherein porting goes through the body. In one example, a conventional pilot-operated check valve 182 is provided in the housing 102, wherein a circlip retains the valve in the housing. Porting can be drilled or otherwise machined into the housing, wherein a ball can be pressed into the housing to seal a hole. Further, porting to a pneumatic source can be provided on any side of the housing, wherein the pneumatic circuitry can be sealed by a pipe plug.
Another option for the pilot operated check valve is to place the check valve 182 in a valve stack (not shown) external to the pin clamp 100. Preferably, however, the check valve 182 is integral to the housing, which can be formed from a solid piece of aluminum, An external valve and/or seals could fail if the check valve were in the valve stack, so the check valve being integral to the body is preferable.
During clamping, the pilot operated check valve provides pneumatic pressure through a first port (e.g., at a first end of the cylinder) and the pneumatic pressure forces the piston one direction to clamp the locating pin, and the pressure is contained in the cylinder until another port is actuated by pneumatic force. To unclamp, pneumatic pressure is provided to the opposite end of the cylinder, wherein the pneumatic pressure is also directed to a third port associated with the check valve. The check valve thus disables the check port, and the air can return. The check valve is generally transparent (e.g., not seen) by the end user, and thus, exposure of any external circuitry is minimized. In the present disclosure, said circuitry is integral to the valve and housing of the pin clamp, thus further not necessitating additional parts.
Although the disclosure has been shown and described with respect to certain aspects, equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described components (systems, devices, assemblies, etc.), the terms used to describe such components are intended to correspond, unless otherwise indicated, to any component which performs the specified function of the described component (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure that performs the function in the herein illustrated exemplary aspects of the disclosure. In addition, while a particular feature of the invention may have been disclosed with respect to only one of several aspects, such feature may be combined with one or more other features of the other aspects as may be desired and advantageous for any given or particular application. Furthermore, to the extent that the term “includes” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising.”
This application claims priority to and the benefit of U.S. Provisional Application Ser. No. 62/001,235 which was filed May 21, 2014, entitled “SLIDING HEAD LOCKING PIN CLAMP”, the entirety of which is hereby incorporated by reference as if fully set forth herein.
Number | Date | Country | |
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62001235 | May 2014 | US |