System, device and method employing machine-readable symbol reader and shield

Machine-readable symbol reader systems including one or more shields are provided. One example machine-readable symbol reader system includes a conveyor system to convey objects bearing one or more machine-readable symbols past a first region that is transmissive to light. The system includes a machine-readable symbol reader having a housing, a window formed in the housing, and at least one optical sensor received in the housing and having a field of view that extends outward of the window, at least the window of the machine-readable symbol reader positioned relatively below the conveyor system with the field of view aligned with the first region of the conveyor system. The system can further include a shield having a frame with a plurality of apertures that are transmissive to light, the shield positioned relatively below the first region and positioned relatively above the window of the machine-readable symbol reader.

BACKGROUND

1. Technical Field

The present disclosure generally relates to machine-readable symbol readers and systems employing such readers, and in particular relates to shields to protect a window of a machine-readable symbol reader.

2. Description of the Related Art

Machine-readable symbols encode information in a form that can be optically read via an appropriately configured machine-readable symbol reader or scanner. Machine-readable symbols take a variety of forms, the most commonly recognized form being the linear or one-dimensional barcode symbol. Other forms include two-dimensional machine-readable symbols such as stacked code symbols, and area or matrix code symbols. These machine-readable symbols are typically composed on patterns of high and low reflectance areas. For instance, a barcode symbol may comprise a pattern of black bars on a white background. Also for instance, a two-dimensional symbol may comprise a pattern of black marks (e.g., bars, squares or hexagons) on a white background. Machine-readable symbols are not limited to being black and white, but may comprise two other colors, and/or may include more than two colors (e.g., more than black and white).

Machine-readable symbols are typically composed of elements (e.g., symbol characters) which are selected from a particular machine-readable symbology. Information is encoded in the particular sequence of shapes (e.g., bars) and spaces which may have varying dimensions. The machine-readable symbology provides a mapping between machine-readable symbols or symbol characters and human-readable symbols (e.g., alpha, numeric, punctuation, commands). A large number of symbologies have been developed and are in use, for example Universal Product Code (UPC), European Article Number (EAN), Code 39, Code 128, Data Matrix, PDF417, etc.

Machine-readable symbols have widespread and varied applications. For example, machine-readable symbols can be used to identify a class of objects (e.g., merchandise) or unique items (e.g., patents). As a result, machine-readable symbols are found on a wide variety of objects, such as retail goods, company assets, and documents, and help track production at manufacturing facilities and inventory at warehouses or in stores (e.g., by scanning items as they arrive and as they are sold). In addition, machine-readable symbols may appear on a display of a portable electronic device, such as a mobile telephone, personal digital assistant, tablet computer, laptop computer, or other device having an electronic display. For example, a customer, such as a shopper, airline passenger, or person attending a sporting event or theater event, may cause a machine-readable symbol to be displayed on their portable electronic device so that an employee (e.g., merchant-employee) can read the machine-readable symbol via a data reader to allow the customer to redeem a coupon or to verify that the customer has purchased a ticket for the event.

Machine-readable symbol readers or data readers are used to capture images or representations of machine-readable symbols appearing on various surfaces to read the information encoded in the machine-readable symbol. One commonly used machine-readable symbol reader is an imager- or imaging-based machine-readable symbol reader. Imaging-based machine-readable symbol readers typically employ flood illumination to simultaneously illuminate the entire machine-readable symbol, either from dedicated light sources, or in some instances using ambient light. Such is in contrast to scanning or laser-based (i.e., flying spot) type machine-readable symbol readers, which scan a relative narrow beam or spot of light sequentially across the machine-readable symbol.

Imaging-based machine-readable symbol readers typically include solid-state image circuitry, such as charge-coupled devices (CCDs) or complementary metal-oxide semiconductor (CMOS) devices, and may be implemented using a one-dimensional or two-dimensional imaging array of photosensors (or pixels) to capture an image of the machine-readable symbol. One-dimensional CCD or CMOS readers capture a linear cross-section of the machine-readable symbol, producing an analog waveform whose amplitude represents the relative darkness and lightness of the machine-readable symbol. Two-dimensional CCD or CMOS readers may capture an entire two-dimensional image. The image is then processed to find and decode a machine-readable symbol. For example, virtual scan line techniques for digitally processing an image containing a machine-readable symbol sample across an image along a plurality of lines, typically spaced apart and at various angles, somewhat like a scan pattern of a laser beam in a scanning or laser-based scanner.

Reading a symbol typically employs generating an electrical signal having an amplitude determined by the intensity of the collected light. Relatively less reflective or darker regions (e.g., bars or other marks) may, for example, be characterized or represented in the electrical signal by an amplitude below a threshold amplitude, while relatively more reflective or lighter regions (e.g., white spaces) may be characterized or represented in the electrical signal an amplitude above the threshold amplitude. When the machine-readable symbol is imaged, positive-going and negative-going transitions in the electrical signal occur, signifying transitions between darker regions and lighter regions. Techniques may be used for detecting edges of darker regions and lighter regions by detecting the transitions of the electrical signal. Techniques may also be used to determine the dimensions (e.g., width) of darker regions and lighter regions based on the relative location of the detected edges and decoding the information represented by the machine-readable symbol.

Some implementations employ a conveyor system (e.g., driven conveyor belt) to move objects bearing machine-readable symbols past a field of view of a machine-readable symbol reader. Such implementations are commonly found at retail checkout or point of sales locations (e.g., grocery store or supermarket checkout counters) and in package sorting systems (e.g., postal or courier distribution centers).

BRIEF SUMMARY

Machine-readable symbol readers typically include a housing that encloses and protects various components of the reader, for instance optical components, a scan engine and/or optical sensor (e.g., CCD array, CMOS image sensor). A window in the housing allows the reception of light by various components of the reader. For example, light reflected or fluoresced from a machine-readable symbol can enter the reader housing through the window. An optical sensor detects the light and produces a representative signal. Circuitry, for instance a processor, processes the representative signal to read the symbol. Components enclosed within the housing can optionally illuminate the machine-readable symbol (e.g., flood illumination, laser or flying spot of light) via the window in the housing.

In some readers, the window includes a glass pane or other transparent or translucent barrier placed across the window opening. The glass pane or other barrier prevents the entry of objects or contaminants into the reader housing. However, contaminants (e.g., dust, dirt, or smudges) can collect on the glass pane and obscure or otherwise inhibit the transmission of light through the window, thereby reducing the accuracy of the reader and requiring periodic cleaning of the glass pane.

Furthermore, glass panes are typically fragile or otherwise susceptible to damage. For example, items (e.g., objects that have fallen from a conveyor system) contacting the glass pane with sufficient force will break or otherwise damage the glass pane. A broken glass pane may require repair or replacement of the pane or the entire reader. Other transparent or translucent barriers, for instance acrylic or polycarbonate barriers may be subject to damage such as marring when struck by falling items. This can adversely affect of the optical characteristics of the transparent or translucent barrier.

In some implementations, a machine-readable symbol reader may be located relatively below a conveyor system that conveys objects bearing machine-readable symbols from a first location to a second location. A machine-readable symbol reader reads each machine-readable symbol as the conveyor system conveys the corresponding object past a field of view of the reader. However, in such a configuration it is possible that one or more of the objects may fall off of the conveyor system during movement. Falling objects or other environmental items that contact the machine-readable symbol reader may damage the reader. Consequently, it is desirable to protect the window of the reader from damage.

It may be possible to place an additional glass or plastic cover in front of the window. However, these items are also susceptible to collection of contaminants, resulting in multiple layers of contaminants between the reader and the symbol and reducing the accuracy of the reader. Therefore, these items may require frequent replacement or cleaning, resulting in additional labor and parts cost. Furthermore, a glass cover is typically insufficient to effectively protect the window against large or heavy objects.

A machine-readable symbol reader system may be summarized as including: a conveyor system to convey objects bearing one or more machine-readable symbols between a first location and a second location past a first region that is transmissive to light; a machine-readable symbol reader having a housing, a window formed in the housing, and at least one optical sensor received in the housing and having a field of view that extends outward of the window, the window transmissive to at least some wavelengths of light, at least the window of the machine-readable symbol reader positioned relatively below the conveyor system with the field of view aligned with the first region of the conveyor system; and a shield having a frame with a plurality of apertures that are transmissive to light, the shield positioned relatively below the first region and positioned relatively above the window of the machine-readable symbol reader.

The shield may include a grate. The shield may include a metal grate. The frame of the shield may include at least one of a plurality of bars or a plurality of wires. Each of the plurality of bars may have a longitudinal axis that is perpendicular to a direction of conveyance in which the conveyor system conveys objects. Each of the plurality of apertures may extend across an entirety of the window in at least one direction to form a plurality of unobstructed optical planes between the first region of the conveyor system and the window. The plurality of apertures may collectively have a first surface area, any portions of the frame that obstruct light may collectively have a second surface area, and the first surface area may be greater than or equal to the second surface area. The shield may be physically coupled to the machine-readable symbol reader. The shield may be integral to the housing and may extend across the window. The window may have a first set of dimensions including at least a first length and a first width, the shield may have a second set of dimensions including at least a second length and a second width, the second length may be at least equal or greater than the first length and the second width may be at least equal or greater than the first width, and the shield may extend across the window.

The machine-readable symbol reader system may further include a blower physically coupled to the shield, the blower may be positioned to cause a circulation of fluid across the window. The conveyor system may include at least a first conveyor assembly and a second conveyor assembly, and the first region of the conveyor system may include a discontinuity between the first conveyor assembly and the second conveyor assembly. The shield may have an upper face, and the shield may be positioned with the upper face at an angle with respect to a direction of gravity. The shield may include one or more components that are selectively electrically energizable to generate heat to defog the window of the machine-readable symbol reader.

A shield to protect a component of a machine-readable symbol reader system, the component having an area and a first set of dimensions including at least a first length and a first width, the shield may be summarized as including: a frame having a plurality of apertures through which light passes, the frame having a second set of dimensions, the second set of dimensions including at least a second length and a second width, the second length at least equal or greater than the first length and the second width at least equal or greater than the first width, the shield positionable relatively above the component to provide a plurality of unobstructed optical planes through the shield to the component while encompassing the area of the component.

The component may be a window of a machine-readable symbol reader. The component may be a mirror. The component may be a housing of a machine-readable symbol reader. The frame of the shield may include at least one of a plurality of metal bars or a plurality of metal wires. The shield may further include one or more components that are selectively electrically energizable to generate heat.

A method of protecting a component of a machine-readable symbol reader system that includes a machine-readable symbol reader having a housing, optical sensor in the housing, and a window transmissive to at least some wavelengths of light, the method may be summarized as including: positioning the machine-readable symbol reader under a portion of a conveyor system to provide the optical sensor with a field of view through the window of objects carried on an upper surface of the conveyor system; and positioning a shield comprising a frame with a plurality of apertures above the component and below the upper surface of the conveyor system, the apertures which pass light through the frame.

Positioning a shield may include positioning the shield above a mirror and below the upper surface of the conveyor system. Positioning a shield may include positioning the shield above the window and below the upper surface of the conveyor system. Positioning a shield may include positioning the shield having a plurality of bars or wires to encompass the window. Positioning a shield may include positioning the shield having a plurality of parallel bars or wires to encompass the window. The shield may be integral to a blower, and positioning the shield above the window may include positioning the blower such that the shield is above the window and below the upper surface of the conveyor system. Positioning the shield above the window and below the upper surface of the conveyor system may include one of physically coupling the shield to the conveyor system or physically coupling the shield to the machine-readable symbol reader. The method may further include electrically energizing one or more parts of the shield to generate heat to defog the component.

DETAILED DESCRIPTION

FIG. 1shows a machine-readable symbol reader system100, according to at least one illustrated embodiment. The system100includes a conveyor system102, a machine-readable symbol reader110, and a shield116.

The conveyor system102conveys objects (e.g., object122) bearing one or more machine-readable symbols (e.g., machine-readable symbol124) between a first location105and a second location107. The conveyor system102conveys objects past a first region108that is transmissive to light. As an example, as shown inFIG. 1, the conveyor system102includes a first conveyor assembly104and a second conveyor assembly106. The first region108that is transmissive to light can, for example, take the form of a discontinuity between the first conveyor assembly104and the second conveyor assembly106. Thus, for example, object122bearing machine-readable symbol124passes across the first region108as object122transits from the first location105to the second location107via the first conveyor assembly104and the second conveyor assembly106.

The machine-readable symbol reader110can be any device capable of reading (e.g., detecting and/or decoding) machine-readable symbols (e.g., PDF417, Code 128, etc.). For example, the machine-readable symbol reader110can be an imaging-based symbol reader, a laser-based symbol reader, or other types of machine-readable symbol readers.

The machine-readable symbol reader110has a housing112that encloses one or more components of the machine-readable symbol reader110. A window114in the housing112is transmissive to at least some wavelengths of light. Generally, the window114is designed and/or positioned relative to the housing112to enable various components received within the housing112to transmit or receive light. For example, light reflected or fluoresced from a machine-readable symbol enters the reader housing112via the window114. The machine-readable symbol reader110may actively illuminate the machine-readable symbol, or may rely on illumination in the ambient environment to illuminate the machine-readable symbol.

An optical sensor received within the housing112detects the light and produces a representative signal. Circuitry, for instance a processor, processes the representative signal to read the symbol. Components enclosed within the housing112can illuminate the machine-readable symbol (e.g., through flood illumination or laser scanning) via the window114, as well.

In some implementations, the window114includes a glass pane or other transparent or translucent barrier placed across the window opening. The glass pane or other barrier can prevent the entry of objects or contaminants, including fine contaminants such as dust or moisture into the reader housing112.

The machine-readable symbol reader system100further includes a shield116positioned to protect at least the window114of the housing112from falling items or debris.

The shield116has a frame117with a plurality of elements118(only one called out) which form a plurality of apertures119(only one called out) that are transmissive to light. The shield116prevents items (e.g., objects falling from the conveyor system102) larger than a defined size (i.e., dimensions of the apertures119) from passing through the shield116.

In some implementations, the shield116takes the form of a grate (e.g., a metal grate). The grate can be shaped as a grill or a grid. In some implementations, the shield116includes a plurality of bars210and/or a plurality of wires or cables310, as will be discussed further with respect toFIGS. 2 and 3respectively. The spacing between the elements118of the frame117of the shield116is set to assure that items likely to damage the machine-readable symbol reader will not pass through the shield116. For example, an item's likelihood of causing damage may be related to density and size or volume and/or type of material (e.g., metal, cardboard, plastic), and the presence or absence of sharp edges or points. The spacing of the elements118may be set to form apertures119with dimensions sufficiently small to prevent the passage of items likely to cause damage, while not overly obscuring a field of view of the machine-readable symbol reader110.

As shown inFIG. 1, the machine-readable symbol reader is positioned relatively below the conveyor system102. The optical sensor received within the housing112captures an image of a field of view that extends outward of the window114. In particular, as shown inFIG. 1, the field of view is aligned with the first region108of the conveyor system102.

The shield116is positioned relatively above the window114and relatively below the conveyor system102. The shield116can be positioned at various distances from the window114.

The machine-readable symbol reader110reads one or more machine-readable symbols present on an object as the object passes over the first region108. In particular, light reflected or fluoresced from a machine-readable symbol passes through the first region108, the apertures119of the shield116, and the window114to reach the optical sensor of the machine-readable symbol reader110. Thus, the shield116protects the window114from environmental hazards (e.g., falling objects or other items) without interfering with the reading or illumination of symbols by the reader110. In particular, in some implementations, the shield116is positioned so that illumination (e.g., laser beam, flood light) can pass through at least one aperture of the shield116and reach the first region108.

In some implementations, conveyor assemblies104and106are conveyor belt assemblies, as shown inFIG. 1. In other implementations, the conveyor system102includes different conveyors in addition or alternatively to belt-based assemblies104and106. For example, conveyor system102can include roller conveyor assemblies, slat conveyor assemblies, wire mesh conveyor assemblies, chutes, and/or other machines or structures for moving objects. In some implementations, the conveyor system102includes only a single conveyor assembly.

Furthermore, althoughFIG. 1shows conveyor assemblies104and106at a same relative height, in some implementations, the assemblies104and106are at different heights, orientations, angles, or directions relative to each other. For example, in some implementations, conveyor assembly106is at a lower relative height than conveyor assembly104, so that the objects more easily transition over the discontinuity between assemblies104and106.

In addition, althoughFIG. 1shows the first region108as a discontinuity between assemblies104and106, such discontinuity is provided as an example only. The conveyor system102can include a first region108that is transmissive to light that has other, different structures. For example, the first region108that is transmissive to light can take the form of an aperture formed within a single conveyor assembly (e.g., an aperture formed between spaced rollers of a roller conveyor assembly), a portion of a conveyor assembly that is transmissive to light (e.g., a clear plastic or glass window embedded within a conveyor assembly), or many other structures. Furthermore, in some implementations, a guide that is transmissive to light is placed in the discontinuity between assemblies104and106.

The housing112of the machine-readable symbol reader110can be formed from various materials or combinations of materials including metals, plastics, rubbers, or other materials. The housing112can be continuous or formed from multiple components that are physically coupled. In some implementations, a user interface (not shown) or other interactive features or components is located on the exterior of the housing112to allow convenient operation. In some implementations, the housing112provides access to various ports or interfaces for permitting electrical or communicative coupling of the machine-readable symbol reader110to other machines or power sources.

The optical sensor of the machine-readable symbol reader110can be a wide range of image sensing devices for converting an optical image (or another wavelength in the electromagnetic spectrum) into an electrical signal. For example, the optical sensor can be a digital sensor, such as a charge-coupled device (CCD) sensor or complimentary metal-oxide semiconductor (CMOS) sensor, both of which can form a one-dimensional or two-dimensional array of pixels, which together constitute an electronic representation of the image. Each pixel location stores data indicative of the light intensity at that location of the image. The light intensity data for each pixel represents a color (e.g., red-green-blue) or monochrome intensity (e.g., grayscale).

In some implementations, in response to receiving an instruction from a controller (not shown), the optical sensor captures or acquires one or more images of the field of view. After the optical sensor has been exposed to light emanating from the field of view, data from all the pixels is sequentially read out in a selectable pattern (which may be row-by-row, sub-region by sub-region, or some other pattern). Optionally, an analog-to-digital converter converts the pixel intensity data to digital form. Other functions or outputs can be performed in addition or alternatively to such pixel intensity data.

In some implementations, the machine-readable symbol reader110further includes an optional illumination source (not shown) to actively illuminate the field of view. The illumination source can be any suitable source of light, such as one or more light emitting diodes (LEDs), flash strobes, incandescent or fluorescent lamps, or halogen bulbs. The illumination source generates light having one or more wavelengths. Alternatively, the machine-readable symbol reader110relies on light from the ambient environment.

One or more illumination drivers or controllers can optionally be provided. The illumination driver applies signals to the illumination source to, for example, strobe the illumination source at desired times or to light the illumination source constantly for a period of time. The illumination source is omitted in certain embodiments. The illumination source can be mounted within the housing112of the machine-readable symbol reader110(e.g., behind window114) or may be mounted external to the housing, such as on an exterior surface of the housing112or remotely located from the machine-readable symbol reader110. For example, the illumination source can be mounted to a separate stand and positioned some distance from the machine-readable symbol reader110.

The optical sensor and the illumination driver connect to the controller, which may be, for example, one or more of a processor, microprocessor, controller, microcontroller, digital signal processor (DSP), graphical processing unit (GPU) or the like (generally “processor”). The connection may be via a bus or other communication mechanism, such as direct connections of a serial, parallel, or other type. The controller generally controls and coordinates the operation of other devices to which it is connected, such as one or more of the optical sensor, the illumination driver, and an audio/visual (A/V) driver.

The A/V driver drives one or more audio devices, such as a buzzer, speaker, or other audible indicator, to produce an audible “beep” or other indication when a machine-readable symbol is successfully read. In addition, or alternatively, the A/V driver drives an LED or other visual indicator device when a machine-readable symbol has been successfully read. Other devices or subsystems, such as a cash register or electronic scale, can also be connected to the controller. Moreover, the controller and/or the bus can interface with other controllers or computers, such as a cash register system or checkout terminal.

In some implementations, the machine-readable symbol reader110includes a memory, which may be implemented using one or more standard memory devices. The memory devices can include, for instance, RAM, ROM, and EEPROM devices, and can also include magnetic or optical storage devices, such as hard disk drives, flash memory, CD-ROM drives, and DVD-ROM drives. The machine-readable symbol reader110may also include an interface coupled to an internal data storage, such as a hard disk drive, flash memory, an optical disk drive, or another memory or drive. The interface may be configured for external drive implementations, such as over a USB, IEEE 1194, Ethernet, and/or RS232 connection.

According to one implementation, any number of program modules are stored in the drives and the memory, including an operating system (OS), one or more application programs or modules, such as instructions to be implemented, and data. Any suitable operating system may be employed. The data can include one or more configuration settings or parameters, or can include image data from the optical sensor and decoded machine-readable symbol data.

The machine-readable symbol reader110can also include or interface with one or more power supplies, which provide electrical power to the various components of the machine-readable symbol reader110via power connections.

Machine-readable symbol readers according to other implementations may have less than all of these components, may contain other components, or both. For example, in some implementations, the machine-readable symbol reader110is a fixed scanner, such as an on-counter scanner or in-counter scanner, or a portable scanner, such as a handheld scanner. In addition, the machine-readable symbol reader110can include a radiofrequency identification (RFID) reader or interrogator and/or or a magnetic stripe reader. Such may be particularly useful when employed as a point-of-sale (POS) terminal.

In some implementations, the machine-readable symbol reader110transmits the decoded machine-readable symbol data to a host or another device (e.g., a computer, a point-of-sale terminal, a point-of-sale computer system, or a cash register). The reader110can transmit the data in a point-to-point manner or via broadcast over a wired or wireless network. The host (or another device) can present data, prompts, and otherwise communicate with a user via one or more display devices. For example, the host (or another device) may present the decoded data to the user via a display, such as the object type (e.g., product type) corresponding to the scanned machine-readable symbol and data associated with the object type (e.g., a price of the product). The data associated with the object type can be encoded in the machine-readable symbol or accessed from a local or remote database based upon the object type. By way of another example, the host (or another device) can cause the decoded data to be recorded on a processor-readable medium. As another example, the host (or another device) can instruct a printer to print the object type and data corresponding to the object type (e.g., print the product type and associated price on a receipt). The machine-readable symbol reader110can also store the decoded machine-readable symbol data in the local memory. For example, if the machine-readable symbol reader110is operating in a portable mode or the host is unavailable, the decoded data can be buffered by the machine-readable symbol reader110for later transmission in a batch mode. Additionally, the machine-readable symbol reader110may acknowledge that machine-readable symbol data has been successfully decoded, such as by sounding a beep customarily associated with machine-readable symbol readers.

In some implementations, as shown inFIG. 1, the shield116is freestanding, or otherwise not physically coupled to either the machine-readable symbol reader110or the conveyor system102. For example, the shield116is held in place or supported by a stand or pedestal. In other implementations, the shield116is coupled to the conveyor system102or other components of the system100.

In some implementations, the shield116heats the window114or other adjacent structures that are transmissive or reflective of light (e.g., one or more mirrors) to prevent fogging. For example, an electrical voltage can be placed across one or more metallic or resistive components of the shield (e.g., resistive heating elements) to provide heating.

The window114has a first set of dimensions including at least a first length and a first width. The shield116has a second set of dimensions including at least a second length and a second width. In some implementations, the second length is at least equal or greater than the first length and the second width is at least equal or greater than the first width. For example, as shown inFIG. 1, the shield116has a width and length that are greater than the width and length of the window114. Therefore, the shield116encompasses the entirety of the window114. The shield116can have any suitable depth or thickness.

In some implementations, each of the plurality of apertures within the shield116(e.g., aperture119) extends across an entirety of the window114in at least one direction to form a plurality of unobstructed optical planes between the first region108of the conveyor system102and the window114. As an example, as shown inFIG. 1, each aperture of the shield116extends across an entire width of the window114to form a plurality of unobstructed optical planes in the horizontal direction relative to the reader112. Thus, for example, the aperture119has a width that is greater than or equal to the width of the window114. However, in other implementations, the unobstructed optical planes are formed in directions other than horizontal relative to the reader112(e.g., vertical or diagonal relative to the reader).

The shield116has an upper face that intercepts objects falling from the conveyor system102. In some implementations, the shield116is positioned with the upper face at an angle with respect to the direction of gravity. Therefore, the upper face of the shield116redirects objects that fall from the conveyor system102away from the shield116and machine-readable symbol reader110, rather than allowing the objects to come to rest upon the upper face.

Although a single machine-readable symbol reader110is depicted inFIG. 1, some implementations of the present disclosure include a plurality of machine-readable symbol readers within the same system or configuration. The plurality of machine-readable symbol readers can be located adjacent to each other (e.g., in an array or other grouping) or can be placed at different positions to, for example, have different fields of view. In such implementations, a single shield116can be positioned to protect some or all of the plurality of machine-readable symbol readers or a plurality of shields can be respectively provided and positioned to protect respective ones of such plurality of machine-readable symbol readers.

In addition, although the machine-readable symbol reader110is located below the conveyor system102inFIG. 1, the present teachings can be applied to other configurations as well, including systems in which the machine-readable symbol reader110is not positioned below a conveyor system. For example, the shields and other aspects of the present disclosure can be applied to systems in which the machine-readable symbol is located above or level with a conveyor system, mounted to a movable structure or vehicle (e.g., a forklift), or used in environments where the machine-readable symbol reader may be exposed to debris travelling at a significant speed (e.g., outdoor environments). Furthermore, aspects of the present disclosure can, in addition to machine-readable symbol readers, be applied to provide shields for other devices that include a window or other aperture transmissive to light such as, for example, certain cameras, laser scanning devices, or other optical devices.

FIG. 2shows a shield200including a frame201with a plurality of bars, according to at least one illustrated embodiment. As shown inFIG. 2, the frame201includes a first side support202, a second side support204, an upper support206, and a lower support208. The supports202-208are pieces of metal, plastic, or other materials. In other implementations, the frame201does not include the upper and lower supports206and208.

The first side support202is physically coupled to the upper support206and the lower support208. Likewise, the second side support204is physically coupled to the upper support206and the lower support208. In some implementations, one or more of welding, fasteners (e.g., screws, bolts, pins, etc.), adhesive, or other coupling means provide the physical connections between respective supports202-208. In other implementations, the supports202-208are a single continuous structure formed using, for example, molding techniques or expanded metal techniques.

The shield200includes a plurality of bars210, such as, for example, bars210a,210b, and210c. The bars210can be metal bars or consist of other materials (e.g., plastics). The bars210can be cylindrical, as shown inFIG. 2, or can have other cross-sectional shapes including rectangular, oval-shaped, wing-shaped, slat-shaped, or other non-geometric cross-sectional shapes. The bars210can be identical to each other or non-identical. In some implementations, as shown inFIG. 2, the bars210are parallel to each other. However, in other implementations, the bars210are not parallel to each other. The bars210of the shield200can be of any thickness. The bars210can be solid or can be hollow such as pipes or tubes to provide shields of lighter weights.

Although not depicted inFIG. 2, in some implementations, the shield200includes one or more beams that provide additional support for the plurality of bars210at various locations. As an example, in some implementations, one or more beams extend from upper support206to lower support208(e.g., across a rear side of the bars210at a position equidistant from first side support202and second side support204) and provide additional support to the bars210. The beams can be physically coupled to the bars210or not physically coupled to the bars210.

The plurality of bars210respectively form a plurality of apertures. The apertures are transmissive to light. For example, bar210aand bar210bform an aperture216therebetween. Likewise, bar210band210cform an aperture218therebetween. As yet another example, bar210cand lower support208form an aperture220therebetween. The spacing between the bars210is set to assure that items likely to damage the machine-readable symbol reader will not pass through the shield200.

The plurality of apertures collectively have a first surface area. Any portions of the frame201that obstruct light collectively have a second surface area. In some implementations, the first surface area is greater than the second surface area. Therefore, the shield200provides protection against damaging items while a majority of its surface area is transmissive to light. In other implementations, the first surface area is less than the second surface area to provide increased protection.

In some implementations of the present disclosure, the shield200is positioned so that a longitudinal axis of each of the plurality of bars210is perpendicular to a direction of conveyance in which a conveyor system conveys objects bearing machine-readable symbols. As an example, referring again toFIG. 1, the shield116includes a plurality of elements118, similar to shield200ofFIG. 2. Conveyor system102conveys objects from location105to location107and past first region108. As shown inFIG. 1, the shield116is positioned so that the longitudinal axis of each of the plurality of elements118is perpendicular to such direction of conveyance.

FIG. 3shows a shield300including a frame301with a plurality of wires, according to at least one illustrated embodiment. The frame301includes a first side support302, a second side support304, an upper support306, and a lower support308. The supports302-308can be pieces of metal, plastic, or other materials. In other implementations, the frame301does not include the upper and lower supports306and308.

The first side support302is physically coupled to the upper support306and the lower support308. Likewise, the second side support304is physically coupled to the upper support306and the lower support308. One or more of welding, fasteners (e.g., screws, bolts, pins, etc.), adhesive, or other coupling means provide the physical connections between respective supports302-308. In other implementations, the supports302-308are a single continuous structure formed using, for example, molding techniques.

The shield300includes a plurality of wires or cables (i.e., plurality of twisted wires)310, such as, for example, wires310a,310b,310c, and310d. The wires can take the form of cables, metal wires, or can include other materials (e.g., metal wires with a plastic coating). The wires or cables310can be identical to each other or non-identical. In some implementations, as shown inFIG. 3, the wires310are parallel to each other. However, in other implementations, the wires310are not parallel to each other.

Although not depicted inFIG. 3, in some implementations, the shield300includes one or more beams that provide additional support for the plurality of wires310at various locations. As an example, in some implementations, one or more beams extend from upper support306to lower support308(e.g., across a rear side of the wires310at a position equidistant from first side support302and second side support304) and provide additional support to the wires310. The beams can be physically coupled to the wires310or not physically coupled to the wires310.

The plurality of wires310respectively form a plurality of apertures that are transmissive to light. For example, wire310and wire310bform an aperture318therebetween. Likewise, wire310band wire310cform an aperture320therebetween. As yet another example, wire310dand lower support308form an aperture322therebetween. The spacing between the wires310is set to assure that items likely to damage the machine-readable symbol reader will not pass through the shield300.

In some implementations, the shield300is positioned so that a longitudinal axis of each of the plurality of wires310is perpendicular to a direction of conveyance in which a conveyor system conveys objects bearing machine-readable symbols. The frame301can maintain the wires310at various levels of tension.

FIG. 4shows a machine-readable symbol reader system400, according to at least one illustrated embodiment. The system400includes a conveyor system402and a machine-readable symbol reader410. A shield416is physically coupled to the machine-readable symbol reader410.

The conveyor system402conveys objects (e.g. object422) bearing one or more machine-readable symbols (e.g., machine-readable symbol424) between a first location405and a second location407. The conveyor system402conveys objects past a first region408that is transmissive to light. The conveyor system402can be the same as or similar to the conveyor system102ofFIG. 1.

As shown inFIG. 4, the conveyor system402includes a first conveyor assembly404and a second conveyor assembly406. The first region408that is transmissive to light can, for example, take the form of a discontinuity between the first conveyor assembly404and the second conveyor assembly406. Thus, for example, object422bearing a machine-readable symbol424passes across the first region408as the object422transits from the first location405to the second location407via the first conveyor assembly404and the second conveyor assembly406.

The machine-readable symbol reader410can be any device capable of reading (e.g., detecting and/or decoding) machine-readable symbols (e.g., PDF417, Code 128, etc.). For example, the machine-readable symbol reader410can be an imaging-based symbol reader, a laser-based symbol reader, or other types of machine-readable symbol readers. The machine-readable symbol reader410can be the same as or similar to the machine-readable symbol reader110ofFIG. 1.

The machine-readable symbol reader410has a housing412. The housing412encloses one or more components of the machine-readable symbol reader410. A window414in the housing412is transmissive to at least some wavelengths of light. Generally, the window414is designed and/or positioned relative to the housing412to enable various components received within the housing412to transmit or receive light. For example, light reflected or fluoresced from a machine-readable symbol enters the reader housing412via the window414. The machine-readable symbol reader410may actively illuminate the machine-readable symbol, or may rely on illumination in the ambient environment to illuminate the machine-readable symbol.

An optical sensor received within the housing412detects the light and produces a representative signal. Circuitry, for instance a processor processes the representative signal to read the symbol. Components enclosed within the housing412can illuminate the machine-readable symbol (e.g., through flood illumination or laser scanning) via the window414, as well.

In some implementations, the window414includes a glass pane or other light transmissive barrier placed across the window opening. The glass pane or other barrier can prevent the entry of objects or contaminants (e.g., dust, moisture) into the reader housing412.

The machine-readable symbol reader system400further includes a shield416physically coupled to the machine-readable symbol reader410. The shield416prevents items larger than a defined size (e.g., objects falling from the conveyor system402) from passing through the shield416.

The shield416has a frame417with a plurality of elements418(only one called out) which form a plurality of apertures419(only one called out) that are transmissive to light. For example, as shown inFIG. 4, the shield416has an aperture419.

In some implementations, the shield416includes a grate (e.g., a metal grate). The grate can be shaped as a grill or a grid. In some implementations, the shield416includes a plurality of bars210. For example, the shield416can be the same as or similar to shield200ofFIG. 2. In some implementations, the shield416includes a plurality of wires310. For example, the shield416can be the same as or similar to shield300ofFIG. 3. The spacing between the elements418of the frame417of the shield416is set to assure that items likely to damage the machine-readable symbol reader will not pass through the shield416. For example, an item's likelihood of causing damage may be related to density and size or volume and/or type of material (e.g., metal, cardboard, plastic), and the presence or absence of sharp edges or points. The spacing of the elements418may be set to form apertures419with dimensions sufficiently small to prevent the passage of items likely to cause damage, while not overly obscuring a field of view of the machine-readable symbol reader410.

As shown inFIG. 4, the machine-readable symbol reader410is positioned relatively below the conveyor system402. The optical sensor received within the housing412captures an image of a field of view that extends outward of the window414. In particular, as shown inFIG. 4, the field of view is aligned with the first region408of the conveyor system402.

The shield416is physically coupled to the machine-readable symbol reader410. In some implementations, the shield416is integral to the housing412of the reader410. For example, the shield416can be embedded within the housing412. In other implementations, one or more of welding, fasteners (e.g., screws, bolts, pins, etc.), adhesive, or other coupling means mount the shield416to the housing412. For example, the shield416can be an after-market addition to the reader410. The shield416can be positioned at various distances from the window414.

The machine-readable symbol reader410reads one or more machine-readable symbols present on an object as the object passes over the first region408. In particular, light reflected or fluoresced from a machine-readable symbol passes through the first region408, the apertures of the shield416, and the window414to reach the optical sensor of the machine-readable symbol reader410. Thus, the shield416protects the window414from environmental hazards (e.g., falling objects) without interfering with the reading or illumination of symbols by the reader410. In particular, in some implementations, the shield416is positioned so that illumination (e.g., laser beam, flood light) can pass through at least one aperture of the shield416and reach the first region408.

In some implementations, conveyor assemblies404and406are conveyor belt assemblies, as shown inFIG. 4. In other implementations, the conveyor system402includes different conveyor types in addition or alternatively to belt-based assemblies404and406. For example, conveyor system402can include roller conveyor assemblies, slat conveyor assemblies, wire mesh conveyor assemblies, chutes, and/or other machines or structures for moving objects. In some implementations, the conveyor system402includes only a single conveyor assembly.

Furthermore, althoughFIG. 4shows conveyor assemblies404and406at a same relative height, in some implementations, the assemblies404and406are at different heights, orientations, angles, or directions relative to each other. For example, in some implementations, conveyor assembly406is at a lower relative height than conveyor assembly404, so that the objects more easily transition over the discontinuity between assemblies.

In addition, althoughFIG. 4shows the first region408as a discontinuity between assemblies404and406, such discontinuity is provided as an example only. The conveyor system402can include a first region408that is transmissive to light that has other, different structures. For example, the first region408that is transmissive to light can take the form of an aperture formed within a single conveyor assembly (e.g., an aperture formed between spaced rollers of a roller conveyor assembly), a portion of a conveyor assembly that is transmissive to light (e.g., a clear plastic or glass window embedded within a conveyor assembly), or many other structures. Furthermore, in some implementations, a guide that is transmissive to light is placed in the discontinuity between assemblies404and406.

The housing412of the machine-readable symbol reader410can be formed from various materials or combinations of materials including metals, plastics, rubbers, or other materials. The housing412can be continuous or formed from multiple components that are physically coupled. In some implementations, a user interface (not shown) or other interactive features or components is located on the exterior of the housing412to allow convenient operation. In some implementations, various ports or interfaces for permitting electrical or communicative coupling of the machine-readable symbol reader410to other machines or power sources are formed within the housing412.

The window414has a first set of dimensions including at least a first length and a first width. The shield416has a second set of dimensions including at least a second length and a second width. In some implementations of the present disclosure, the second length is at least equal or greater than the first length and the second width is at least equal or greater than the first width. For example, as shown inFIG. 4, the shield416has a width that is greater than the width of the window414. Therefore, the shield416encompasses the entire width of the window414.

In some implementations, each of the plurality of apertures419within the shield416extends across an entirety of the window414in at least one direction to form a plurality of unobstructed optical planes between the first region408of the conveyor system402and the window414. As an example, as shown inFIG. 4, each aperture419of the shield416extends across an entire width of the window414to form a plurality of unobstructed optical planes in the horizontal direction relative to the reader412. However, in other implementations, the unobstructed optical planes are formed in directions other than horizontal relative to the reader412(e.g., vertical or diagonal relative to the reader).

The shield416has an upper face that intercepts objects falling from the conveyor system402. In some implementations, the shield416is positioned with the upper face at an angle with respect to the direction of gravity. Therefore, the upper face of the shield416redirects objects that fall from the conveyor system402away from the shield416and machine-readable symbol reader410, rather than allowing the objects to come to rest upon the upper face.

FIG. 5shows a machine-readable symbol reader500with a shield506integral thereto, according to at least one illustrated embodiment. The machine-readable symbol reader500can be any device capable of reading (e.g., detecting and/or decoding) machine-readable symbols. For example, machine-readable symbol reader500can be the same as or similar to the machine-readable symbol reader110ofFIG. 1.

Machine-readable symbol reader500has a housing502that encloses one or more components of the reader500. A window504in the housing502is transmissive to at least some wavelengths of light.

The shield506is physically coupled to the machine-readable symbol reader500. In particular, as shown inFIG. 5, the shield506can be integral to the reader housing502and can extend across the window504.

As shown inFIG. 5, the shield506includes a plurality of bars, including, for example, bars508and510. The bars can be metal bars or can be formed of other materials. The bars of shield506can be the same as or similar to the bars210of shield200ofFIG. 2. In some implementations, shield506includes a plurality of wires in addition to or alternatively to the plurality of bars. For example, the wires can be the same as or similar to the wires310of shield300ofFIG. 3.

The shield506includes a plurality of apertures that are transmissive to light. For example, bars508and510form an aperture512therebetween.

As shown inFIG. 5, the plurality of bars of the shield506are embedded within the housing502. More particularly, each bar has a least a first end portion that is embedded within a first portion514of the housing502adjacent to a first side of the window504and a second end portion that is embedded within a second portion516of the housing502adjacent to a second side of the window504. The second side of the window504is opposite the first side of the window504. A center portion of each bar that is not embedded within the housing502extends across the window504.

FIG. 6shows a machine-readable symbol reader600, according to at least one illustrated embodiment. A shield606is carried by or mounted to the reader600.

The machine-readable symbol reader600can be any device capable of reading (e.g., detecting and/or decoding) machine-readable symbols. For example, machine-readable symbol reader600can be the same as or similar to the machine-readable symbol reader110ofFIG. 1.

Machine-readable symbol reader600has a housing602that encloses one or more components of the reader600. A window604in the housing602is transmissive to at least some wavelengths of light.

A shield606is physically coupled to the machine-readable symbol reader600. In particular, as shown inFIG. 6, the shield606is mounted to the housing602in front of the window604. One or more of fasteners (e.g., screws as shown inFIG. 6), welding, adhesive, or other coupling means mount the shield606to the reader600. Thus, in some implementations, the housing602has one or more recesses for respectively receiving the one or more fasteners.

As shown inFIG. 6, the shield606includes a first side support608and a second side support610. The first and second side supports608and610are positioned at opposite sides of the window604and are respectively physically coupled to the housing602using one or more fasteners.

The shield606further includes a plurality of bars, including, for example, bars612and614. The bars can be metal bars or can be formed of other materials. The bars of shield606can be the same as or similar to the bars of shield200ofFIG. 2. In some implementations, shield606includes a plurality of wires in addition to or alternatively to the plurality of bars. For example, the wires can be the same as or similar to the wires of shield300ofFIG. 3.

The shield606includes a plurality of apertures that are transmissive to light. For example, bars612and614form an aperture616therebetween.

FIG. 7shows a machine-readable symbol reader system700, according to at least one illustrated embodiment. The system700includes a conveyor system702, a machine-readable symbol reader710, and a blower716. A shield720is physically coupled to the blower716.

The conveyor system702conveys objects (e.g., object724) bearing one or more machine-readable symbols (e.g., machine-readable symbol726) between a first location705and a second location707. The conveyor system702conveys objects past a first region708that is transmissive to light. The conveyor system702can be the same as or similar to the conveyor system102ofFIG. 1.

As shown inFIG. 7, the conveyor system702includes a first conveyor assembly704and a second conveyor assembly706. The first region708that is transmissive to light can, for example, take the form of a discontinuity between the first conveyor assembly704and the second conveyor assembly706. Thus, for example, object724bearing a machine-readable symbol726passes across the first region708as the object724transits from the first location705to the second location707via the first conveyor assembly704and the second conveyor assembly706.

The machine-readable symbol reader710can be any device capable of reading (e.g., detecting and/or decoding) machine-readable symbols (e.g., PDF717, Code 128, etc.). For example, the machine-readable symbol reader710can be an imaging-based symbol reader, a laser-based symbol reader, or other types of machine-readable symbol readers. The machine-readable symbol reader710can be the same as or similar to the machine-readable symbol reader110ofFIG. 1.

The machine-readable symbol reader710has a housing712. The housing712encloses one or more components of the machine-readable symbol reader710. A window714in the housing712is transmissive to at least some wavelengths of light. Generally, the window714is designed and/or positioned relative to the housing712to enable various components received within the housing712to transmit or receive light. For example, light reflected or fluoresced from a machine-readable symbol enters the reader housing712via the window714. The machine-readable symbol reader710may actively illuminate the machine-readable symbol, or may rely on illumination in the ambient environment to illuminate the machine-readable symbol.

An optical sensor received within the housing712detects the light and produces a representative signal. Circuitry, for instance a processor, processes the representative signal to read the symbol. Components enclosed within the housing712can illuminate the machine-readable symbol (e.g., through flood illumination or laser scanning) via the window714, as well.

In some implementations, the window714includes a glass pane or other light transmissive barrier placed across the window opening. The glass pane or other light transmissive barrier can prevent the entry of objects or contaminants into the reader housing712.

The system700further includes a blower716. The blower716causes circulation of a fluid (e.g., air) across the window714. Thus, the blower716can include a fan or other components for causing the movement of at least one fluid. In some implementations, the blower716blows the fluid out of a vent718. The vent718directs the circulation of fluid across the window714.

The blower716can be stationary or can have components that periodically rotate. In some implementations, the blower716is physically coupled to the machine-readable symbol reader710. For example, the reader710rests upon the blower716. In other implementations, brackets respectively hold the reader710and the blower716adjacent to each other. The blower716can have many shapes or designs different than the example shape shown inFIG. 7.

The machine-readable symbol reader system700further includes a shield720physically coupled to blower716. The shield720prevents items larger than a defined size (e.g., objects falling from the conveyor system702) from passing through the shield720.

The shield720has a frame721with a plurality of elements722(only one called out) which form a plurality of apertures723(only one called out) that are transmissive to light. The shield720prevents items (e.g., objects falling from the conveyor system702) larger than a defined size (i.e., dimensions of the apertures723) from passing through the shield720.

In some implementations, the shield720includes a grate (e.g., a metal grate). The grate can be shaped as a grill or a grid. In some implementations, the shield720includes a plurality of bars210. For example, the shield720can be the same as or similar to shield200ofFIG. 2. In some implementations, the shield720includes a plurality of wires310. For example, the shield720can be the same as or similar to shield300ofFIG. 3. The spacing between the elements722of the frame721of the shield720is set to assure that items likely to damage the machine-readable symbol reader will not pass through the shield720. For example, an item's likelihood of causing damage may be related to density and size or volume and/or type of material (e.g., metal, cardboard, plastic), and the presence or absence of sharp edges or points. The spacing of the elements722may be set to form apertures723with dimensions sufficiently small to prevent the passage of items likely to cause damage, while not overly obscuring a field of view of the machine-readable symbol reader710.

As shown inFIG. 7, the machine-readable symbol reader is positioned relatively below the conveyor system702. The optical sensor received within the housing712captures an image of a field of view that extends outward of the window714. In particular, as shown inFIG. 7, the field of view is aligned with the first region708of the conveyor system702.

The shield720is physically coupled to the blower716. The blower716is positioned so that the shield720is placed in front of the window714. In some implementations, the shield720is integral to the blower716. In other implementations, one or more of welding, fasteners (e.g., screws, bolts, pins, etc.), adhesive, or other coupling means mount the shield720to the blower716. For example, the shield720can be an after-market addition to the blower716. The shield720can be positioned at various distances from the window714.

The machine-readable symbol reader710reads one or more machine-readable symbols present on an object as the object passes over the first region708. In particular, light reflected or fluoresced from a machine-readable symbol passes through the first region708, the apertures723of the shield720, and the window714to reach the optical sensor of the machine-readable symbol reader710. Thus, the shield720protects the window714from environmental hazards (e.g., falling objects) without interfering with the reading or illumination of symbols by the reader710. In particular, in some implementations, the shield720is positioned so that an illumination (e.g., laser beam, flood light) can pass through at least one aperture of the shield720and reach the first region708.

In some implementations, conveyor assemblies704and706are conveyor belt assemblies, as shown inFIG. 7. In other implementations, the conveyor system702includes different conveyor types in addition or alternatively to belt-based assemblies704and706. For example, conveyor system702can include roller conveyor assemblies, slat conveyor assemblies, wire mesh conveyor assemblies, chutes, and/or other machines or structures for moving objects. In some implementations, the conveyor system702includes only a single conveyor assembly.

Furthermore, althoughFIG. 7shows conveyor assemblies704and706at a same relative height, in some implementations, the assemblies704and706are at different heights, orientations, angles, or directions relative to each other. For example, in some implementations, conveyor assembly706is at a lower relative height than conveyor assembly704, so that the objects more easily transition over the discontinuity between assemblies.

In addition, althoughFIG. 7shows the first region708as a discontinuity between assemblies704and706, such discontinuity is provided as an example only. The conveyor system702can include a first region708that is transmissive to light that has other, different structures. For example, the first region708that is transmissive to light can take the form of an aperture formed within a single conveyor assembly (e.g., an aperture formed between spaced rollers of a roller conveyor assembly), a portion of a conveyor assembly that is transmissive to light (e.g., a clear plastic or glass window embedded within a conveyor assembly), or many other structures. Furthermore, in some implementations, a guide that is transmissive to light is placed in the discontinuity between assemblies704and706.

The housing712of the machine-readable symbol reader710can be formed from various materials or combinations of materials including metals, plastics, rubbers, or other materials. The housing712can be continuous or formed from multiple components that are physically coupled. In some implementations, a user interface (not shown) or other interactive features or components is located on the exterior of the housing712to allow convenient operation. In some implementations, various ports or interfaces for permitting electrical or communicative coupling of the machine-readable symbol reader710to other machines or power sources are formed within the housing712.

The window714has a first set of dimensions including at least a first length and a first width. The shield720has a second set of dimensions including at least a second length and a second width. In some implementations of the present disclosure, the second length is at least equal or greater than the first length and the second width is at least equal or greater than the first width. For example, as shown inFIG. 7, the shield720has a width that is greater than the width of the window714and a length that is greater than the length of the window714. Therefore, the shield720encompasses the entire width and length of the window714.

In some implementations, each of the plurality of apertures723within the shield720extends across an entirety of the window714in at least one direction to form a plurality of unobstructed optical planes between the first region708of the conveyor system702and the window714. As an example, as shown inFIG. 7, each aperture of the shield720extends across an entire width of the window714to form a plurality of unobstructed optical planes in the horizontal direction relative to the reader712. Thus, for example, the apertures723have a width that is greater than or equal to the width of the window714. However, in other implementations, the unobstructed optical planes are formed in directions other than horizontal relative to the reader712(e.g., vertical or diagonal relative to the reader).

The shield720has an upper face that intercepts objects falling from the conveyor system702. In some implementations, the shield720is positioned with the upper face at an angle with respect to the direction of gravity. Therefore, the upper face of the shield720redirects objects that fall from the conveyor system702away from the shield720and machine-readable symbol reader710, rather than allowing the objects to come to rest upon the upper face.

FIG. 8shows a machine-readable symbol reader system800, according to at least one illustrated embodiment. The system800includes a conveyor system802and a machine-readable symbol reader810. A shield816is positioned to protect a mirror830.

The conveyor system802conveys objects (e.g. object822) bearing one or more machine-readable symbols (e.g., machine-readable symbol824) between a first location805and a second location807. The conveyor system802conveys objects past a first region808that is transmissive to light. The conveyor system802can be the same as or similar to the conveyor system102ofFIG. 1.

As shown inFIG. 8, the conveyor system802includes a first conveyor assembly804and a second conveyor assembly806. The first region808that is transmissive to light can, for example, take the form of a discontinuity between the first conveyor assembly804and the second conveyor assembly806. Thus, for example, object822bearing a machine-readable symbol824passes across the first region808as the object822transits from the first location805to the second location807via the first conveyor assembly804and the second conveyor assembly806.

The machine-readable symbol reader810can be any device capable of reading (e.g., detecting and/or decoding) machine-readable symbols (e.g., PDF817, Code 128, etc.). For example, the machine-readable symbol reader810can be an imaging-based symbol reader, a laser-based symbol reader, or other types of machine-readable symbol readers. The machine-readable symbol reader810can be the same as or similar to the machine-readable symbol reader110ofFIG. 1.

The machine-readable symbol reader810has a housing812. The housing812encloses one or more components of the machine-readable symbol reader810. A window in the housing812is transmissive to at least some wavelengths of light. Generally, the window is designed and/or positioned relative to the housing812to enable various components received within the housing812to transmit or receive light. For example, light reflected or fluoresced from a machine-readable symbol enters the reader housing812via the window. The machine-readable symbol reader810may actively illuminate the machine-readable symbol, or may rely on illumination in the ambient environment to illuminate the machine-readable symbol.

An optical sensor received within the housing812detects the light and produces a representative signal. Circuitry, for instance a processor processes the representative signal to read the symbol. Components enclosed within the housing812can illuminate the machine-readable symbol (e.g., through flood illumination or laser scanning) via the window, as well.

In some implementations, the window includes a glass pane or other light transmissive barrier placed across the window opening. The glass pane or other barrier can prevent the entry of objects or contaminants (e.g., dust, moisture) into the reader housing812.

The machine-readable symbol reader system800further includes a shield816that is positioned to protect a mirror830of the system300. The shield816prevents items larger than a defined size (e.g., objects falling from the conveyor system802) from passing through the shield816. The shield816can be positioned at various distances from the mirror830.

The shield816has a frame817with a plurality of elements818(only one called out) which form a plurality of apertures819(only one called out) that are transmissive to light. For example, as shown inFIG. 8, the shield816has an aperture819.

In some implementations, the shield816includes a grate (e.g., a metal grate). The grate can be shaped as a grill or a grid. In some implementations, the shield816includes a plurality of bars210. For example, the shield816can be the same as or similar to shield200ofFIG. 2. In some implementations, the shield816includes a plurality of wires310. For example, the shield816can be the same as or similar to shield300ofFIG. 3. The spacing between the elements818of the frame817of the shield816is set to assure that items likely to damage the machine-readable symbol reader will not pass through the shield816. For example, an item's likelihood of causing damage may be related to density and size or volume and/or type of material (e.g., metal, cardboard, plastic), and the presence or absence of sharp edges or points. The spacing of the elements818may be set to form apertures819with dimensions sufficiently small to prevent the passage of items likely to cause damage, while not overly obscuring a field of view of the machine-readable symbol reader810.

As shown inFIG. 8, the machine-readable symbol reader810is positioned relatively below the conveyor system802. The optical sensor received within the housing812captures an image of a field of view that extends outward of the window. In particular, as shown inFIG. 8, the field of view is aligned with the first region808of the conveyor system802via reflection by the mirror830according to an optical path832.

More particularly, the mirror830reflects light to redirect the optical path832associated with the field of view of the machine-readable symbol reader810. In particular, the mirror830can redirect light reflected or fluoresced from a machine-readable symbol (e.g., symbol824) towards the window of the machine-readable symbol reader810. Likewise, the mirror830can redirect illumination light emitted by the machine-readable symbol reader810(e.g., laser beam or flood light) towards the first region808, as illustrated by the optical path832. The mirror830can be any type of mirror or other optically reflective device including, for example, a metal-coated mirror, a dielectric mirror, or other such devices.

Thus, the machine-readable symbol reader810reads one or more machine-readable symbols present on an object as the object passes over the first region808. In particular, light reflected or fluoresced from a machine-readable symbol passes through the first region808and the apertures of the shield816, is reflected by the mirror830, and passes through the window to reach the optical sensor of the machine-readable symbol reader810. The light reflected or fluoresced from a machine-readable symbol may or may not pass through the apertures of the shield816after reflection by the mirror, depending on the location of such components.

Thus, the shield816protects the mirror830from environmental hazards (e.g., falling objects) without interfering with the reading or illumination of symbols by the reader810via the optical path832. In particular, in some implementations, the shield816is positioned so that illumination (e.g., laser beam, flood light) can pass through at least one aperture of the shield816and reach the first region808.

In some implementations, conveyor assemblies804and806are conveyor belt assemblies, as shown inFIG. 8. In other implementations, the conveyor system802includes different conveyor types in addition or alternatively to belt-based assemblies804and806. For example, conveyor system802can include roller conveyor assemblies, slat conveyor assemblies, wire mesh conveyor assemblies, chutes, and/or other machines or structures for moving objects. In some implementations, the conveyor system802includes only a single conveyor assembly.

Furthermore, althoughFIG. 8shows conveyor assemblies804and806at a same relative height, in some implementations, the assemblies804and806are at different heights, orientations, angles, or directions relative to each other. For example, in some implementations, conveyor assembly806is at a lower relative height than conveyor assembly804, so that the objects more easily transition over the discontinuity between assemblies.

In addition, althoughFIG. 8shows the first region808as a discontinuity between assemblies804and806, such discontinuity is provided as an example only. The conveyor system802can include a first region808that is transmissive to light that has other, different structures. For example, the first region808that is transmissive to light can take the form of an aperture formed within a single conveyor assembly (e.g., an aperture formed between spaced rollers of a roller conveyor assembly), a portion of a conveyor assembly that is transmissive to light (e.g., a clear plastic or glass window embedded within a conveyor assembly), or many other structures. Furthermore, in some implementations, a guide that is transmissive to light is placed in the discontinuity between assemblies804and806.

The housing812of the machine-readable symbol reader810can be formed from various materials or combinations of materials including metals, plastics, rubbers, or other materials. The housing812can be continuous or formed from multiple components that are physically coupled. In some implementations, a user interface (not shown) or other interactive features or components is located on the exterior of the housing812to allow convenient operation. In some implementations, various ports or interfaces for permitting electrical or communicative coupling of the machine-readable symbol reader810to other machines or power sources are formed within the housing812.

The mirror830has a first set of dimensions including at least a first length and a first width. The shield816has a second set of dimensions including at least a second length and a second width. In some implementations of the present disclosure, the second length is at least equal or greater than the first length and the second width is at least equal or greater than the first width. For example, as shown inFIG. 8, the shield816has a width and a length that is greater than the width and the length of the mirror830. Therefore, the shield816encompasses the entire area of the mirror830.

In some implementations, each of the plurality of apertures819within the shield816extends across an entirety of the mirror830in at least one direction to form a plurality of unobstructed optical planes between the first region808of the conveyor system802and the mirror830. As an example, as shown inFIG. 8, each aperture819of the shield816extends across an entire width of the mirror830to form a plurality of unobstructed optical planes in the horizontal direction relative to the mirror830. However, in other implementations, the unobstructed optical planes are formed in directions other than horizontal relative to the mirror830(e.g., vertical or diagonal relative to the mirror).

The shield816has an upper face that intercepts objects falling from the conveyor system802. In some implementations, the shield816is positioned with the upper face at an angle with respect to the direction of gravity. Therefore, the upper face of the shield816redirects objects that fall from the conveyor system802away from the shield816and mirror830, rather than allowing the objects to come to rest upon the upper face.

In addition, althoughFIG. 8depicts shield816positioned to protect mirror830, in some implementations, the shield816can be positioned to protect both the mirror830and the machine-readable symbol reader810simultaneously. In other implementations, an additional shield (e.g., similar to shield816) can be positioned to protect the machine-readable symbol reader810while shield816protects mirror830.

FIG. 9is a flow chart diagram showing a method900of protecting a machine-readable symbol reader, according to at least one illustrated embodiment. The method begins at902.

At902, a machine-readable symbol reader is positioned under a portion of a conveyor system to provide an optical sensor with a field of view through a window of objects carried on an upper surface of the conveyor system. As an example, as shown inFIG. 1, the machine-readable symbol reader110is positioned under a portion of the conveyor system102to provide the optical sensor of the reader110with a field of view through window114of objects carried on the upper surface of the conveyor system102. As another example, as shown inFIG. 8, the machine-readable symbol reader810is positioned under a portion of the conveyor system802to provide the optical sensor of the reader810with a field of view via optical path832of objects carried on the upper surface of the conveyor system802.

Referring again toFIG. 9, at904a shield comprising a frame with a plurality of apertures is positioned above a component of the machine-readable symbol reader system and below the upper surface of the conveyor system, the apertures which pass light through the frame. The component can be a mirror. As an example, as shown inFIG. 8, the shield816is positioned above the mirror830and below the upper surface of the conveyor system802. The apertures819of the shield816pass light through the shield816.

Referring again toFIG. 9, in other implementations, the component above which the shield is positioned can be a window of a machine-readable symbol reader. As an example, as shown inFIG. 1, the shield116is positioned above the window114and below the upper surface of the conveyor system102. The apertures119of shield116pass light through the shield116.

Referring again toFIG. 9, in some implementations, positioning the shield at904includes positioning a shield having a plurality of bars or a plurality of wires to encompass the window. As another example, in some implementations, positioning the shield at904includes positioning a shield having a plurality of parallel bars or a plurality of parallel wires to encompass the window.

In further implementations, the shield is integral to a blower and positioning the shield at904includes positioning the blower such that the shield is above the window and below the upper surface of the conveyor system. As an example, as shown inFIG. 7, the shield720is physically coupled to the blower716and the blower716is positioned such that the shield720is above the window714and below the upper surface of the conveyor system702.

Referring again toFIG. 9, in some implementations, positioning the shield at904includes one or more of physically coupling the shield to the conveyor system or physically coupling the shield to the machine-readable symbol reader. For example, one or more of welding, fasteners (e.g., screws, bolts, pins, etc.), adhesive, or other coupling means can physically couple the shield to the conveyor system and/or the machine-readable symbol reader.

Those of skill in the art will recognize that many of the methods or algorithms set out herein may employ additional acts, may omit some acts, and/or may execute acts in a different order than specified.

The various embodiments described above can be combined to provide further embodiments. Aspects of the embodiments can be modified, if necessary, to employ systems, circuits and concepts of the various patents, applications and publications to provide yet further embodiments.